A team led by Dr. Derrick Gibbings, a professor in the Department of Cellular and Molecular Medicine at the University of Ottawa and a member of the Eric Poulin Centre for Neuromuscular Disease, has now reported a two-part strategy that addresses both halves of the problem: getting antibody drugs across the barrier, and making them actually destructive once they arrive. The work, led by research associate Huishan Guo in the Gibbings laboratory, was published in the journal Nature Biomedical Engineering on 26 August 2026 under the title “Engineered autophagy receptors administered with extracellular vesicles eliminate pathological Tau and TDP-43.”

The delivery half of the solution relies on extracellular vesicles, tiny membrane-bound bubbles that cells naturally release into their surroundings. These vesicles ferry proteins, RNA and other cargo between cells as part of normal biology, and crucially, they have evolved ways of moving across the blood-brain barrier that synthetic drug carriers have not. The Ottawa researchers showed that extracellular vesicles can squeeze through the walls of blood vessels and enter the brain, carrying their molecular passengers with them. By loading therapeutic antibodies into or alongside these natural shuttles, the team found a way to dramatically raise the fraction of drug that reaches its target tissue, sidestepping the barrier that strands conventional antibody infusions in the blood.

Delivery alone, however, was never going to be enough. As Gibbings explains, antibodies raised against the pathological proteins behind Alzheimer’s disease, dementias and amyotrophic lateral sclerosis can bind their targets but cannot destroy them. “Normal antibodies can attach themselves to the disease-causing proteins in these diseases, but they can’t eliminate them and so aren’t as potent as they could be,” he says. In other words, a conventional antibody acts like a flag planted on a piece of debris, marking it for other systems to deal with, while the protein itself persists and continues to accumulate in the brain.

The second innovation therefore recruits one of the cell’s oldest housekeeping systems: autophagy. Often described as the body’s natural recycling plant, autophagy collects damaged or unwanted material inside the cell, engulfs it in a membrane sac and delivers it to the cellular machinery that breaks it down into small components the cell can reuse. The process is normally activated when cells are stressed or deprived of nutrients, and it is a fundamental mechanism by which cells clear their own molecular garbage. What the Ottawa team did was to hijack this disposal system and point it at the very proteins that drive neurodegeneration.

The researchers engineered antibodies that carry what the team describes as a baggage tag. When such an antibody binds a disease-causing protein, the tag recruits the autophagy machinery, directing the entire antibody-protein complex into the cell’s garbage disposal system for destruction. Rather than merely tagging pathological proteins and hoping something else clears them, these engineered molecules convert the immune recognition event into an active demolition order. The approach builds on a growing body of cell biology showing that autophagy receptors, the adaptor proteins that link cargo to the recycling machinery, can be repurposed to degrade specific targets on demand.

In cells and in mouse models, the strategy produced striking results. The team reported that engaging autophagy greatly improved the elimination of the proteins that cause Alzheimer’s disease, dementia and amyotrophic lateral sclerosis, and that the mice showed improvements in their disease symptoms. The pathological targets named in the published study, Tau and TDP-43, are two of the most notorious culprits in neurodegeneration. Tau tangles are a hallmark of Alzheimer’s disease and related dementias, while TDP-43 aggregates define the pathology of amyotrophic lateral sclerosis and frontotemporal dementia. A single platform capable of clearing both classes of proteins, and doing so through the cell’s own disposal route, represents a meaningful conceptual advance over approaches that only block or neutralize their targets.

The published work is described as a randomized controlled study performed in animals, and Gibbings is careful to frame it as a first step rather than a cure. Treating mice is one step, but an important one, on the road toward clinical trials and demonstrating benefits in patients, he notes. The history of neurodegenerative disease research is littered with therapies that looked powerful in animal models and failed to translate, which is precisely why the delivery component of this work may prove as consequential as the degradation component. A drug that cannot reach the brain cannot help the brain, no matter how elegant its mechanism.

There is nonetheless considerable momentum behind the underlying drug class. “There is a lot of enthusiasm for antibodies like these in industry, with many of the major pharma and biotech companies having invested billions of dollars in this space,” Gibbings says. “Many of these antibodies have been tried in patients in clinical trials but have shown minimal benefits to patients so far. We hope our new strategy to get these antibodies into the brain and eliminate their targets may be a key to making these drugs work for patients.” That framing captures the stakes: the molecules themselves are not new, but the combination of vesicle-based delivery and autophagy-directed destruction could finally give them the reach and the killing power they have lacked.

If the approach survives the long road to human testing, it could reshape how the field thinks about treating diseases of the central nervous system. Instead of designing ever-better antibodies and hoping a fraction of each dose crosses the barrier, researchers could pair existing recognition molecules with natural cellular transport systems and with the cell’s own recycling machinery. The Ottawa team’s results suggest that the barrier can be crossed, that pathological proteins can be actively destroyed rather than merely flagged, and that symptoms in animal models can improve as a result. For the millions of people living with ALS, Alzheimer’s, Parkinson’s and other dementias, that combination of delivery and destruction may be the key that turns decades of antibody investment into real therapeutic benefit.

Subject of Research: Engineered autophagy-recruiting antibodies delivered by extracellular vesicles to eliminate pathological Tau and TDP-43 in neurodegenerative disease models

Article Title: New drug-delivery method offers promise in fight against neurodegenerative diseases

Article References: New drug-delivery method offers promise in fight against neurodegenerative diseases. (n.d.). Original publication

Image Credits: AI Generated

DOI: Not provided

Keywords: neurodegenerative diseases, extracellular vesicles, autophagy, blood-brain barrier, antibody drugs, Tau, TDP-43, ALS, Alzheimer's disease, University of Ottawa, drug-delivery, method

The study, published in Nature Communications, enrolled eighteen patients with suspected normal pressure hydrocephalus, a neurological condition that already requires neurosurgery. These patients were undergoing ventriculoperitoneal shunt placement, a procedure in which a tube is implanted to drain excess cerebrospinal fluid. Because the surgery already involves passing through the parieto-occipital cortex, the surgeons were able to take a tiny rice-grain-sized core of brain tissue at the same time, with the patients’ informed consent. Before the operation, each participant received an intravenous infusion of isotopically labelled leucine, an amino acid that crosses the blood-brain barrier and becomes incorporated into newly synthesized proteins. By measuring how much of this label appeared in tau and amyloid-beta proteins extracted from the biopsy, the researchers could determine when those molecules were made.

This technique, known as stable isotope labelling kinetics, has been used before to measure protein turnover in cerebrospinal fluid, but never before has it been combined with direct sampling of living human brain tissue in this way. The result is a kind of molecular timestamp. Proteins carrying the heavy carbon signature of the labelled leucine were manufactured during the hours or days before surgery; proteins without it are older. The approach gives researchers something that post-mortem studies fundamentally cannot: a snapshot of disease biology in real time, at the very earliest stages of the Alzheimer continuum, before symptoms have fully declared themselves.

What the team found in those tiny biopsies was striking. Half of the samples contained amyloid-beta pathology, visible as cored plaques, diffuse deposits and, in one case, cerebral amyloid angiopathy, where amyloid accumulates in blood vessel walls. Tau pathology, the second hallmark, was present but limited, appearing mostly as neuritic threads and tau associated with plaques rather than the mature neurofibrillary tangles seen in end-stage disease. Crucially, the researchers showed that phosphorylated tau, specifically the pTau217 form that has become one of the most accurate blood-based biomarkers for Alzheimer disease, was physically concentrated within and around the amyloid plaques themselves. The signal decreased progressively with distance from the plaque centre, providing direct visual evidence in living human tissue that tau phosphorylation and amyloid deposition are spatially coupled.

This co-localization matters because it speaks to one of the central unanswered questions in Alzheimer research: how amyloid and tau interact to drive neurodegeneration. Dystrophic neurites, the swollen and damaged neuronal processes that surround plaques, contain phosphorylated tau and are associated with synaptic dysfunction. The new findings suggest that this periplaque tau pool, rather than the aggregated tau inside mature tangles, may be the source of the pTau217 that appears in cerebrospinal fluid and blood. That would explain why fluid levels of this biomarker track so closely with plaque burden, and it offers a mechanistic explanation for why amyloid-targeting antibodies such as donanemab, which specifically clears pyroglutamate-modified amyloid-beta, also slow the accumulation of tau pathology even though they have no direct effect on tau metabolism.

The isotope labelling also yielded a remarkable measurement of tau biology. Labelled leucine was detectable in newly synthesized tau protein within just over three hours of the infusion starting, demonstrating that tau is translated rapidly in the human brain. By modelling the decay of the isotopic signal across the cohort, the researchers estimated that the half-life of tau in brain tissue is approximately thirty-four days, broadly consistent with the roughly twenty-three-day turnover previously measured in lumbar cerebrospinal fluid. When the researchers stratified their samples by plaque status, they found that tau labelling was significantly higher in biopsy samples that contained amyloid plaques compared to those that did not, providing ex vivo support for the idea that amyloid pathology drives increased tau production.

In sharp contrast to tau, the amyloid-beta peptides in the insoluble plaque fraction showed no detectable isotope labelling at all, despite the researchers using assays sensitive enough to detect enrichment as low as 1.87 percent and validating their findings across two independent mass spectrometry laboratories. This absence is not a technical failure but a biological finding in its own right. It suggests that amyloid plaques are remarkably stable structures, built up over years or decades, that do not dynamically incorporate significant amounts of new amyloid-beta within the few-hour window of the labelling period. The plaques in these early-stage samples were chemically immature, containing less than forty percent isomerised amyloid-beta species, compared with roughly ninety percent isomerisation in post-mortem Alzheimer tissue, where plaques have had years to accumulate molecular damage.

That isomerisation clock is one of the most conceptually powerful tools to emerge from this work. Aspartate residues in amyloid-beta spontaneously convert from their native L-form to non-native isomeric forms over time, at a rate that can be used to estimate the age of a plaque. Previous work has suggested that around fifty percent isomerisation corresponds to a mean plaque age of roughly eight months, while eighty-five percent indicates an age of about four years. By quantifying these isomers in living tissue, the researchers could distinguish freshly formed, immature plaques from older, more established deposits. This kind of molecular dating has never before been possible in living human brain, and it opens the door to staging the disease biochemically rather than relying on crude measures of plaque quantity, which notoriously correlate poorly with cognitive symptoms.

The team also used matrix-assisted laser desorption ionization mass spectrometry imaging to map the chemical architecture of individual plaques at ten-micrometre resolution. This revealed a striking degree of spatial organization within single deposits. Amyloid-beta 1-40 and pyroglutamate-modified amyloid-beta species were concentrated in the dense plaque core, while amyloid-beta 1-42 and related C-terminal species were distributed more homogeneously across both the core and the diffuse periphery. This peptide-specific spatial segregation, previously observed only in mouse models and post-mortem tissue, confirms that pyroglutamate-modified amyloid sits at the growing edge of plaques and may be a key driver of plaque expansion, making it a particularly relevant target for immunotherapies like donanemab that are designed to clear exactly this modified species.

One further finding carries practical implications for how Alzheimer biomarkers are interpreted. The researchers compared tau profiles in ventricular cerebrospinal fluid, collected during shunt surgery directly from the brain’s fluid spaces, with those in lumbar cerebrospinal fluid collected from the lower spine. Ventricular fluid closely mirrored the tau peptide profile seen in brain tissue itself, while lumbar fluid showed a distinctly different pattern with reduced C-terminal abundance. The team attributes this partly to iatrogenic contamination, as the shunt insertion procedure inevitably releases intracellular brain proteins into the ventricular fluid. Even so, the observation that ventricular cerebrospinal fluid can serve as a surrogate for brain tissue chemistry is significant, particularly for normal pressure hydrocephalus patients, in whom amyloid pathology is common and brain biopsy during shunt surgery is already practised as a diagnostic adjunct by many specialists.

The study is a proof of principle, and the authors are careful to acknowledge its limitations. The cohort is small, the participants were recruited for a hydrocephalus indication rather than Alzheimer disease itself, and the biopsies came from a single brain region that may not represent disease burden elsewhere. The tau half-life estimate rests on a statistical model with sparse timepoints around the peak of the labelling curve. Even so, the conceptual advance is hard to overstate. For the first time, researchers have captured the molecular birth of Alzheimer pathology in living human brains, dated plaques by their chemistry, watched tau being synthesized in real time, and visualized the physical interface between the disease’s two hallmark proteins. The methods developed here should be applicable to other neurodegenerative conditions, and they promise to reshape how clinical trials of the future are designed, allowing therapies to be matched to the specific molecular stage of disease rather than to symptoms alone.

Subject of Research: Molecular characterization of amyloid and tau pathology in living human brain tissue using stable isotope labelling and mass spectrometry imaging

Article Title: Spatiotemporal characterization of Alzheimer disease pathology in living human brain tissue

Article References: Aslanyan, A., Mukherjee, S., Moncur, E. M., Szadziewska, A., He, Y., Kac, P. R., Coyle, R., Camporesi, E., Sato, C., Ghoshal, N., Barthélemy, N. R., Wood, J., Ge, J., Dulewicz, M., Koutarapu, S., Schwetye, K., Roberts, K. F., Murphy, E. C., Carletti, F., … Paterson, R. W. (2026). Spatiotemporal characterization of Alzheimer disease pathology in living human brain tissue. Nature Communications, 17(1), Article 9878. https://doi.org/10.1038/s41467-026-76494-4

Image Credits: AI Generated

DOI: 10.1038/s41467-026-76494-4

Keywords: Alzheimer disease, amyloid-beta, tau, stable isotope labelling, mass spectrometry imaging, normal pressure hydrocephalus, pTau217, pyroglutamate, protein turnover, biomarkers, brain biopsy, neurodegeneration

The story begins with exon 10 of the MAPT gene. Tau exists in the human brain as six isoforms, distinguished by whether they contain three or four microtubule-binding repeats, the so-called 3R and 4R forms. The inclusion or skipping of exon 10 determines which repeat is present, and the normal adult brain maintains a roughly balanced ratio of the two. When that ratio slips, the consequences can be devastating: mutations and splicing dysregulation around exon 10 are linked to a family of disorders including progressive supranuclear palsy, corticobasal degeneration, Pick’s disease, and frontotemporal dementia with parkinsonism linked to chromosome 17, as well as Alzheimer’s disease itself, where neurofibrillary tangles of tau accumulate inside dying neurons.

Scientists have known for years that exon 10 is governed by an intricate web of cis-acting sequence elements and trans-acting proteins. Previous work had implicated factors such as TDP-43, hnRNP A1, Rbfox3, and hnRNP C in controlling this splicing decision. The new study, led by Yaqiong Yu and colleagues with senior authors Tao Jiang and Deng Xiao, adds HuR, also known as ELAVL1, to that roster, and does so with a mechanistic depth that distinguishes it from a simple correlation. Using a combination of reporter assays, binding studies, and transcriptome-wide analyses, the team demonstrated that HuR does not merely associate with the MAPT pre-messenger RNA; it actively suppresses the inclusion of exon 10.

The mechanistic core of the finding lies in a specific structural domain of the HuR protein. HuR belongs to the embryonic lethal abnormal vision family of RNA-binding proteins and carries three RNA recognition motifs, or RRMs. Through systematic domain analysis, the researchers showed that the first of these motifs, RRM1, is critical for HuR’s splicing-inhibitory effect on exon 10. When this domain’s function was disrupted, the repressive effect was lost. This level of resolution matters because it converts a broad observation, that HuR touches tau RNA, into a testable molecular model in which a defined protein surface contacts a defined RNA target to alter a splicing outcome relevant to human disease.

Where exactly does HuR bind? The answer, according to the study, is a uridine-rich stretch of sequence located downstream of intron 9 in the MAPT pre-mRNA, immediately adjacent to the exon 10 region whose inclusion it represses. U-rich elements are a classic signature of ELAV-family protein binding, and genome-wide surveys have previously revealed that a large proportion of AU-rich elements across the human transcriptome sit within introns, where they can influence splicing as well as mRNA stability. The intronic location of the HuR binding site in MAPT fits this pattern neatly and provides a plausible physical mechanism: by occupying the downstream intron, HuR may interfere with the spliceosome’s recognition of the exon, tipping the balance toward skipping.

Perhaps the most intriguing aspect of the study is its demonstration that HuR does not work alone. The researchers found that HuR binds the U-rich region in MAPT together with a cohort of cooperating RNA-binding proteins: FUBP1, KHSRP, hnRNPD, hnRNPAB, hnRNPDL, and TIAL1. Splicing decisions in mammalian cells are rarely made by a single factor; instead, regulatory complexes assemble cooperatively on pre-mRNA, and the combined occupancy of activators and repressors determines the final output. The identification of this multi-protein assembly at the tau exon 10 locus suggests that the ratio of 3R to 4R tau is set by a network rather than a switch, with HuR functioning as one node whose influence depends on its partners.

Adding another layer of complexity, the team observed that HuR expression shows a negative relationship with the expression of several of these partners, including FUBP1, KHSRP, hnRNPD, and TIAL1. Such inverse expression patterns hint at cross-regulatory circuits among RNA-binding proteins, a phenomenon documented before in the hnRNP family, where auto- and cross-regulation help maintain proteostasis of the splicing machinery. If HuR and its co-factors restrain one another’s abundance, then perturbations that shift one factor, whether through aging, stress signaling, or disease processes, could ripple through the entire complex and reshape tau splicing in neurons. This systems-level view reframes tauopathies not as failures of a single gene but as failures of a regulatory network.

The implications extend well beyond MAPT. When the researchers examined the broader consequences of altering HuR levels, they found that the protein regulates both the expression and the alternative splicing of genes involved in autophagy and apoptosis, the cellular self-cleaning and self-destruction pathways that are famously dysregulated in Alzheimer’s disease. Defective autophagy is thought to contribute to the accumulation of amyloid-beta and phosphorylated tau, while inappropriate apoptosis drives neuronal loss. The idea that a single RNA-binding protein sits upstream of splicing programs in both pathways positions HuR as a potential coordinator of several AD-relevant transcriptomic networks simultaneously, a convergence point where multiple disease processes might intersect.

This broader role is consistent with a growing literature on the ELAV family in the nervous system. HuR has been shown to control the RNA metabolism of glutaminase, to regulate age-related hearing loss in mice, and to interact with amyloid precursor protein in ways that promote apoptosis under amyloid-beta stress. Its cousin ELAVL4 has been implicated in splicing changes and glutamatergic dysfunction that precede neuron loss in cerebral organoids carrying MAPT mutations, and ELAVL2-family biology has been linked to neuroprotection in retinal ganglion cells. The new study slots neatly into this picture while adding something genuinely new: a direct, mechanistically resolved connection between HuR and the splicing event most tightly associated with tauopathy.

Therapeutically, the timing is notable. Antisense oligonucleotides targeting tau are already in clinical trials, with a phase 1b study of the MAPT-targeting agent MAPTRx in mild Alzheimer’s disease demonstrating that tau-directed RNA therapies can reach the nervous system safely. A splicing-factor approach would represent a different strategy: rather than reducing total tau, it would aim to restore the correct 3R-to-4R ratio by modulating the proteins that decide exon 10’s fate. The identification of RRM1 as the critical functional domain of HuR provides a concrete target for such efforts, whether through small molecules that disrupt the HuR-RNA interaction or through oligonucleotides that mask the U-rich binding site in intron 9. Similar splicing-correction approaches have already rescued mis-splicing in other genetic diseases, including sensorineural hearing loss and spinal muscular atrophy, proving the concept is feasible.

Caution is warranted, as it always is in this field. HuR is a multifunctional protein with hundreds of documented RNA targets, and global manipulation of its activity could produce unintended effects in cells throughout the body. The negative correlations between HuR and its co-factor expression, while suggestive, raise questions about cause and effect that will require longitudinal and cell-type-specific studies to resolve. Moreover, the study was conducted without human participants or animal subjects, so translating these molecular findings into living brains remains a substantial journey. Even so, the work delivers something Alzheimer’s research badly needs: a new, mechanistically grounded entry point into the splicing decisions that shape tau biology, and a reminder that the answers to neurodegeneration may lie not only in the proteins that misfold, but in the RNA editors that decide which versions of those proteins are made in the first place.

Subject of Research: The role of the RNA-binding protein HuR in regulating alternative splicing of MAPT and other Alzheimer's disease-related genes

Article Title: HuR modulates disease-relevant alternative splicing of MAPT and other Alzheimer's disease-related genes

Article References: Yu, Y., Liu, S., Ma, C., Tan, M., Min, L., Jiang, T., & Xiao, D. (2026). HuR modulates disease-relevant alternative splicing of MAPT and other Alzheimer's disease-related genes. Molecular Genetics and Genomics, 301(1), Article 202. https://doi.org/10.1007/s00438-026-02527-8

Image Credits: AI Generated

DOI: 10.1007/s00438-026-02527-8

Keywords: HuR, ELAVL1, MAPT, tau, alternative splicing, Alzheimer's disease, tauopathies, exon 10, RNA-binding proteins, autophagy, apoptosis, neurodegeneration

The modification in question is a phosphate group attached to the 65th amino acid of ubiquitin, a serine residue, producing what researchers abbreviate as pS65-Ub. This is not a random chemical accident. Phosphorylated ubiquitin at this exact position is the product of PINK1, a kinase enzyme famous for its role in mitochondrial quality control. When mitochondria are damaged, PINK1 accumulates on their outer membranes and phosphorylates ubiquitin there, launching a signaling cascade that tags the doomed organelles for removal by autophagy. Mutations in PINK1 cause early-onset Parkinson’s disease, which is why most research on pS65-Ub has historically focused on the Parkinson’s field. But the new work places this stress signal squarely inside the biology of Alzheimer’s disease, connecting cellular stress pathways with the propagation of pathological tau.

Previous studies had already established that pS65-Ub accumulates in Alzheimer’s brains and that its abundance rises alongside tau pathology. What remained unknown was whether the phosphorylated ubiquitin had any functional relationship to tau seeding, the process by which small aggregates of tau act as templates that corrupt normally folded tau molecules into the same misfolded shape. Seeding is widely regarded as the engine of disease progression in Alzheimer’s, because tau pathology does not remain static. It appears in restricted brain regions early in the disease and then spreads in a stereotyped pattern across the brain over years, a pattern that tracks closely with cognitive decline. Identifying which tau molecules are capable of seeding, as opposed to merely being present, has been a persistent technical challenge because the pathological and normal forms of the protein are chemically very similar.

To address this question, the Mayo team turned to postmortem human brain tissue from both female and male donors with Alzheimer’s disease, using a combination of biochemical fractionation, immunoprecipitation, and sensitive seeding assays. Their first key observation was that a subset of tau in the Alzheimer’s brain is covalently modified by pS65-Ub. In other words, the phosphorylated ubiquitin is not merely floating in the same cellular neighborhoods as tau; it is chemically bonded to tau molecules themselves, forming conjugates in which the stress signal and the pathological protein are physically linked. This covalent relationship is significant because it means the modification can serve as a specific tag that distinguishes one population of tau from all the rest.

The properties of this pS65-Ub-associated tau population turned out to be striking. When the researchers compared Alzheimer’s brain tissue with control tissue, they found that the tagged tau was elevated in the disease state. More importantly, it was enriched in the fractions of tau that are considered most pathological: tau that remains soluble rather than being locked into insoluble deposits, tau that migrates as high-molecular-weight oligomers rather than as single molecules, and tau that is hyperphosphorylated, the heavily modified state characteristic of disease. Soluble oligomeric tau is widely believed to be the toxic species in Alzheimer’s, more damaging to synapses and neurons than the large, insoluble fibrils that dominate the visible pathology under the microscope. The fact that pS65-Ub preferentially marks this soluble, oligomeric, hyperphosphorylated fraction suggested it might be pointing directly at the culprit.

The correlation data strengthened that suspicion considerably. Across the Alzheimer’s cases examined in the study, the levels of soluble pS65-Ub-associated tau tracked strongly with tau seeding activity measured from the same tissue samples. Seeding activity is typically quantified using biosensor cells, in this case tau-FRET biosensor cells developed in Marc Diamond’s laboratory, which fluoresce when internalized tau seeds induce intracellular tau to aggregate. The tight relationship between the amount of tagged tau and the measured seeding capacity implies that pS65-Ub is not an incidental passenger on pathological tau but a genuine marker of the seed-competent population. For a field that has struggled to distinguish dangerous tau from harmless tau in patient samples, this correlation is a potentially transformative analytical tool.

Causality, however, requires more than correlation, and the team designed experiments to test whether the tagged tau was functionally responsible for seeding. When they isolated tau species using antibodies against pS65-Ub, the captured material exhibited seeding activity in the biosensor assays, confirming that the tagged fraction contains active seeds. The complementary experiment was even more telling: when the researchers removed the pS65-Ub-associated material from Alzheimer’s brain extracts, the seeding activity of the remaining extract dropped markedly. Depleting the tagged tau did not merely reduce one component of the seeding signal; it substantially diminished the overall infectious-like capacity of the brain extract. Together, these gain-of-function and loss-of-function results argue that the pS65-Ub-tagged tau population accounts for a large share of the seeding activity present in Alzheimer’s brain tissue.

The conceptual implications of the study extend beyond Alzheimer’s disease itself. By demonstrating that a PINK1-derived stress signal is covalently attached to the tau population that propagates disease, the work draws a direct mechanistic line between cellular stress responses and the spread of protein misfolding. This suggests a model in which mitochondrial or proteostatic stress, by generating phosphorylated ubiquitin, becomes intertwined with the tau aggregation process, potentially marking tau molecules that have been processed through stressed quality-control pathways. Whether pS65-Ub conjugation actively promotes tau’s seeding competence or simply accumulates on tau that has already become seed-competent remains an open question, and answering it will be a priority for follow-up research. Either way, the stress signal serves as an enriched molecular feature of the population that matters most for disease progression.

From a translational standpoint, the findings open several concrete avenues. A biomarker capable of reporting on seed-competent tau would be invaluable for clinical trials, where measuring total tau or phosphorylated tau in cerebrospinal fluid and blood provides only a rough index of pathology burden rather than a readout of active disease mechanisms. If soluble pS65-Ub-associated tau can be detected in biofluids, it could serve as a pharmacodynamic marker indicating whether an experimental treatment is actually reducing the pool of propagation-competent tau. The modification also presents a potential therapeutic target: if the enzymes or pathways responsible for conjugating pS65-Ub to tau can be identified and modulated, it might become possible to interfere with the formation or stability of the seed-competent tau population itself. Additionally, antibodies raised against pS65-Ub, the same reagents used to deplete seeding activity in this study, could inform immunotherapy strategies aimed at selectively clearing the most dangerous tau species.

Important caveats remain. The study was conducted on postmortem tissue, which captures the end state of the disease and cannot by itself establish the temporal sequence of events leading to tau seeding in living patients. The work also focused on Alzheimer’s disease, and it will be worth examining whether pS65-Ub-associated tau plays a similar role in other tauopathies, such as progressive supranuclear palsy and corticobasal degeneration, where tau aggregates adopt different molecular conformations. Nevertheless, by identifying a disease-enriched, covalent molecular feature of the seed-competent tau population and demonstrating its strong association with seeding activity across human cases, the Mayo Clinic team has provided the Alzheimer’s research community with both a new analytical lens and a set of testable hypotheses. The study, published as an open-access article in Nature Communications with the DOI 10.1038/s41467-026-78418-8, reflects contributions from neuropathology and proteomics cores at Mayo Clinic and was supported by funders including the Florida Department of Health, the Alzheimer’s Association, the National Institutes of Health, and the Michael J. Fox Foundation for Parkinson’s Research, an apt reminder of how insights from Parkinson’s disease biology can illuminate the mechanisms of Alzheimer’s.

Subject of Research: Phosphorylated ubiquitin as a marker of seed-competent tau in Alzheimer's disease

Article Title: Serine-65 phosphorylated ubiquitin associates with soluble tau and seeding activity in Alzheimer’s disease

Article References: Yan, T., Hou, X., Watzlawik, J. O., Dickson, D. W., Fiesel, F. C., & Springer, W. (2026). Serine-65 phosphorylated ubiquitin associates with soluble tau and seeding activity in Alzheimer’s disease. Nature Communications. https://doi.org/10.1038/s41467-026-78418-8

Image Credits: AI Generated

DOI: 10.1038/s41467-026-78418-8

Keywords: Alzheimer's disease, tau, phosphorylated ubiquitin, PINK1, tau seeding, protein aggregation, neurodegeneration, biomarkers, postmortem brain tissue, oligomeric tau, cellular stress, Nature Communications

The scientific problem at the heart of the project is one of the most stubborn in modern medicine. Protein misfolding and aggregation are associated with Alzheimer’s disease, amyotrophic lateral sclerosis (ALS), some cancers and a range of other chronic and degenerative conditions. Yet many of the proteins involved have long been considered essentially undruggable, because they lack the stable three-dimensional shapes and well-defined binding pockets that most drug development strategies are built to exploit. When a protein does not hold still, designing a molecule to grip it becomes a formidable challenge.

Team SEEDS, whose full name is Sequence-to-disease: Environment-aware Ensembles of Disordered proteins at Scale, is co-led by Priyanka Joshi of Georgetown University and Chuankai (Kai) Zhou of the Buck Institute. The consortium unites expertise in protein science, artificial intelligence, computational modeling, cancer biology and neuroscience, drawing on researchers from nine academic institutions and seven industry partners. Its shared goal is to build a platform capable of mitigating diseases driven by misfolded proteins, moving the field from describing these molecules one at a time to predicting their behavior from their amino acid sequence and their surroundings alike.

The proteins under study are known as intrinsically disordered proteins, or IDPs. Unlike many proteins that fold into relatively fixed structures, IDPs constantly shift among many different conformations. Conditions inside the cell, including acidity, molecular crowding, metals, metabolites and chemical modifications, can influence which forms they adopt and how they behave. That flexibility allows IDPs to carry out important functions in healthy cells, but it also makes them extraordinarily difficult to understand and target when something goes wrong. Current techniques can capture snapshots of these proteins, often only after they have already clumped together, but researchers cannot reliably predict how they will behave as cellular conditions change, or when those changes begin to become harmful.

Artificial intelligence tools such as AlphaFold have transformed protein science by learning from decades of accumulated structural data, but the same wealth of information does not exist for intrinsically disordered proteins, which makes building predictive models far harder. SEEDS aims to help close that gap by developing new experimental and computational ways to study these molecules and by mapping their behavior at unprecedented scale. Crucially, the team plans to pair computational predictions with experimental measurements, testing protein behavior under varying conditions rather than relying on computer models alone.

Zhou framed the effort in explicitly preventive terms. The team aims to uncover the principles that determine when these proteins remain in healthy functional ensembles and when they begin to shift toward disease-associated states, he said, adding that the work could ultimately enable researchers to detect and potentially redirect harmful conformational changes before they lead to irreversible cellular damage. Central to that ambition is understanding how a protein’s environment shapes its behavior, since the same sequence can follow very different trajectories depending on the molecular company it keeps.

Joshi described the challenge with a question that brought the team together: can researchers recognize when a protein is headed in a harmful direction before it arrives, and if so, can they change its course? She compares the task to learning the grammar of a language. Scientists need to examine proteins at scale while also studying some closely enough to understand how their behavior shifts with context. By combining physics-guided artificial intelligence with experiments that test and refine the model’s predictions, the consortium hopes to uncover the molecular grammar connecting protein sequence and environment to behavior. The objective, in her words, is to catch the seed before it grows into disease.

SEEDS operates under ARPA-H’s BIOmolecular Grammar for protein Aggregation Modulation and Intervention (BIOGAMI) program, led by ARPA-H Program Manager Shannon Greene. BIOGAMI concentrates on the earliest stages of protein dysfunction, before misfolding or clumping inflicts lasting cellular damage. Within the consortium, two complementary research teams attack the problem from different directions. At the Buck Institute, SHIFT, short for Structural Characterization of Intrinsically Disordered Regions at Scale, will map the context-dependent shapes that disordered regions can take across a broad range of human proteins, revealing patterns that single-protein studies cannot capture. At Georgetown, INTREPID, the INTegRated Environment-aware Prediction Engine for Intrinsically Disordered Protein Pathology, will examine in depth how sequence and cellular environment affect the range of shapes a protein can adopt. Researchers there will combine high-throughput and high-resolution measurements, computation and artificial intelligence, focusing on tau, implicated in Alzheimer’s disease, and EWS::FLI1, implicated in Ewing sarcoma, studying both from purified systems through human tissue. Data from the two teams will be integrated to train foundation models designed to predict the context-dependent conformational ensembles of intrinsically disordered regions.

The consortium assembles a deep bench of specialists. At Georgetown, Joshi will work alongside Jeffrey Toretsky, whose research centers on Ewing sarcoma and the disordered EWS::FLI1 protein; R. Scott Turner, director of Georgetown’s Memory Disorders Program, who brings longitudinal clinical, imaging and biomarker expertise; Carlo Tornatore, who leads the neurology department at Georgetown and MedStar Health; Rodrigo Maillard, an expert in single-molecule biophysics; Steven Metallo, who studies small-molecule interactions with disordered proteins; Junfeng Ma, a specialist in mass spectrometry-based proteomics; and Mark Burns and Harshul Pandit, whose work includes preclinical models of tau pathology. At the Buck Institute, Zhou will be joined by Tara Tracy, who specializes in translational tauopathy research and therapeutic discovery, and Birgit Schilling, director of the Institute’s Proteomics and Metabolomics Center, with expertise in protein-protein interaction networks and mass spectrometry-based assays. Academic collaborators include principal investigators at the University of Maryland, Baltimore; the University of Maryland, Baltimore County; CIRMMP; Stanford University; the University of California, San Francisco; the University of Denver; and Memorial Sloan Kettering Cancer Center. Industry partners, among them Nautilus Biotechnology, Nanost, Emergente, Neuroene Therapeutics, Post Translational Medicines, Praio and Omphalos Lifesciences, contribute technologies spanning protein mapping, diagnostics, computational modeling and therapeutic development.

Leaders at both institutions emphasized the broader stakes of the initiative. Eric Verdin, president and CEO of the Buck Institute, said the project reflects how the institute approaches diseases of aging by moving beyond treating disease after it presents and working instead to prevent the earliest molecular changes that drive dysfunction, adding that SEEDS has the potential to create an entirely new framework for understanding, and someday intervening in, the chronic diseases of aging. Norman J. Beauchamp Jr., executive vice president for health sciences at Georgetown University, noted that the most difficult health challenges are rarely solved by one discipline or institution working alone, and that many diseases linked to these proteins have resisted the field’s best efforts while taking an enormous toll on patients and families. If the consortium can better predict when these proteins are headed toward disease and find ways to intervene, he suggested, researchers may change what is possible for patients and families. The research is funded in part by ARPA-H, and the views expressed by the participating institutions do not necessarily represent the official policies of the U.S. Government.

Subject of Research: Prediction and intervention in intrinsically disordered protein misfolding linked to neurodegenerative disease and cancer

Article Title: Up to $51.7 million ARPA-H award backs Georgetown University and Buck Institute co-led “super team” to predict and intervene in harmful protein changes before disease begins

Article References: Up to $51.7 million ARPA-H award backs Georgetown University and Buck Institute co-led “super team” to predict and intervene in harmful protein changes before disease begins. (n.d.). Original publication

Image Credits: AI Generated

DOI: Not provided

Keywords: ARPA-H, protein misfolding, intrinsically disordered proteins, Alzheimer's disease, Ewing sarcoma, artificial intelligence, BIOGAMI, Georgetown University, Buck Institute, tau, EWS::FLI1, drug development

The choice of model organism is central to the study’s design. The team used Drosophila melanogaster flies genetically modified to express human amyloid-beta 42, the sticky peptide that aggregates into the plaques characteristic of Alzheimer’s disease. Although flies are distant from humans on the evolutionary tree, they share a remarkable proportion of their genes with people, and many of the molecular pathways implicated in neurodegeneration, including oxidative stress responses, cholinergic signalling, and tau phosphorylation cascades, are conserved. Fruit flies also live for only weeks, which means researchers can observe the full course of a neurodegenerative process and test interventions across the lifespan in a matter of days, something impossible in rodent or human studies. In this experiment, the Alzheimer-model flies were treated with the Caralluma extract for fourteen days before being assessed.

The behavioural results were the most visible evidence of benefit. Flies carrying the human amyloid-beta 42 gene typically show progressive deterioration in climbing ability, a standard measure of locomotor function in fly neurodegeneration research, as well as impaired grooming and deficits in learning assays. Treated flies performed significantly better across these measures and lived longer than their untreated counterparts. The researchers used an aversive phototaxis suppression assay to probe learning and memory, a test that measures a fly’s ability to suppress its natural attraction to light when that light is paired with an unpleasant stimulus. Improved performance in this assay suggests that the extract protected cognitive function, not merely motor capacity, although the authors are careful to frame these as preliminary findings in an invertebrate system.

Beneath the behavioural improvements, the biochemical data pointed to a familiar theme in neurodegeneration research: oxidative stress. The brains of Alzheimer-model flies suffer from an excess of reactive oxygen species that damage lipids, proteins, and DNA. The team measured malondialdehyde, a breakdown product of lipid peroxidation that serves as a marker of oxidative damage, and found it reduced in treated flies. At the same time, levels of the antioxidants glutathione and superoxide dismutase, two of the cell’s primary defences against oxidative injury, were increased. This shift in the balance between oxidative damage and antioxidant capacity is consistent with a neuroprotective effect and aligns with the known chemistry of many plant-derived polyphenols, which can act as antioxidants directly and can also induce the cell’s own antioxidant defence systems.

Perhaps the most pharmacologically interesting finding concerned acetylcholinesterase, the enzyme that breaks down the neurotransmitter acetylcholine. Cholinergic neurons in the brain are among the earliest casualties of Alzheimer’s disease, and the loss of acetylcholine contributes substantially to the memory impairment that defines the condition. Four of the currently approved Alzheimer’s drugs, including donepezil and galantamine, work by inhibiting acetylcholinesterase to keep acetylcholine available for longer in the synaptic cleft. In the treated flies, acetylcholinesterase levels were significantly reduced, suggesting that the extract may reproduce, at least partially, the mechanism of existing symptomatic therapies through a natural product mixture.

The molecular layer of the study focused on tau, the microtubule-associated protein whose pathological tangles inside neurons form the second hallmark lesion of Alzheimer’s disease alongside amyloid plaques. Quantitative analysis showed that the fly equivalent of the tau gene, dTau, was downregulated in extract-treated flies compared with untreated Alzheimer-model flies. Because tau pathology correlates more closely with cognitive decline than amyloid burden in human disease, any intervention that reduces tau expression or the signalling that drives tau phosphorylation attracts considerable attention. The researchers propose that the extract may be acting upstream of tau through pathways that connect amyloid toxicity to tau dysfunction.

To explore those upstream connections, the team turned to molecular docking, a computational technique that predicts how well small molecules fit into the binding pockets of target proteins. They focused on two enzymes with central roles in Alzheimer’s biology: glycogen synthase kinase-3, known as GSK3, and beta-secretase 1, known as BACE1. GSK3 is the major kinase that phosphorylates tau in the brain, promoting its aggregation into tangles, and it also participates in inflammatory and apoptotic signalling. BACE1 is the enzyme that performs the first cut in the production of amyloid-beta from its parent protein, making it a prime drug target for reducing amyloid generation. Docking simulations suggested that several phytochemicals present in the extract interact favourably with both enzymes, with catechin, a flavonoid found in many plants, showing the most promising predicted binding profiles against GSK3 and BACE1 alike.

The authors are explicit that docking is a hypothesis-generating tool rather than proof of mechanism. Predicted binding energies do not confirm that catechin or any other constituent of the extract actually inhibits GSK3 or BACE1 inside a living organism, and the extract is a complex mixture whose active components and their concentrations remain to be fully characterised. The study also did not directly measure amyloid-beta deposition or tau phosphorylation in the fly brains, so the link between the observed gene expression changes and the actual pathological lesions of Alzheimer’s disease remains to be established. Direct target validation, the authors note, together with assessment of amyloid and tau pathology and studies in mammalian models, will be required before any therapeutic relevance can be claimed.

Even with those caveats, the study fills a genuine gap. Caralluma dalzielii has a long history of traditional use for neurological complaints in the region where it grows across the Sahel and West Africa, yet it had never previously been evaluated in an experimental model of Alzheimer’s disease. Its close relative Caralluma fimbriata has been studied mainly for appetite suppression, and the genus as a whole remains underexplored relative to its chemical richness. Plants in this group produce an array of pregnane glycosides, flavonoids, and other secondary metabolites, and the new findings suggest that some of these compounds may act on multiple nodes of the Alzheimer’s disease network simultaneously, a polypharmacology that single-target drugs often lack.

The research also demonstrates the continuing value of the humble fruit fly in early-stage drug discovery. A complete behavioural, biochemical, and molecular evaluation of a natural product extract was accomplished in a model system that is inexpensive, rapid, and free of the ethical and logistical constraints of vertebrate studies, supported by funding from Nigeria’s TETFund institutional research programme. For a disease that affects tens of millions of people worldwide and for which approved therapies offer only modest symptomatic benefit, the pipeline of candidate compounds needs every accessible entry point. The Nigerian team’s results do not amount to a treatment, and no one should interpret them as a recommendation to seek out the plant itself. What they provide is a rigorous preliminary signal, generated through a transparent and reproducible workflow, that Caralluma dalzielii deserves a place in the queue of natural products being screened for Alzheimer’s drug discovery. If catechin and its neighbours in the extract can be isolated, validated against GSK3 and BACE1 in vitro, and tested in mammalian models of the disease, this Sahelian succulent may yet contribute more to modern medicine than its traditional reputation alone ever suggested.

Subject of Research: Neuroprotective effects of Caralluma dalzielii extract in a transgenic Drosophila model of Alzheimer's disease

Article Title: Targeting Alzheimer’s disease pathways with Caralluma dalzielii: behavioural, biochemical, and molecular evidence from a transgenic Drosophila melanogaster model

Article References: Ugwah-Oguejiofor, C. J., Hassan, E., Yakubu, D., Ahmed, A. H., Almustapha, Z., & Imam, M. U. (2026). Targeting Alzheimer’s disease pathways with Caralluma dalzielii: behavioural, biochemical, and molecular evidence from a transgenic Drosophila melanogaster model. BMC Complementary Medicine and Therapies. https://doi.org/10.1186/s12906-026-05637-3

Image Credits: AI Generated

DOI: 10.1186/s12906-026-05637-3

Keywords: Caralluma dalzielii, Alzheimer's disease, Drosophila melanogaster, amyloid-beta 42, tau, GSK3, BACE1, acetylcholinesterase, oxidative stress, catechin, phytochemicals, molecular docking

The nucleolus is the busiest manufacturing hub in the cell. It forms around clusters of ribosomal DNA repeats, where the enzyme RNA polymerase I transcribes them into precursor ribosomal RNA at a ferocious pace, producing the raw material for ribosome assembly. Because this transcriptional output consumes enormous cellular resources, the nucleolus doubles as a sensitive sensor of cellular well-being. When nucleolar function is disturbed, the structure disintegrates and stabilises the tumour suppressor p53, which can halt the cell cycle or trigger programmed cell death. Previous work had hinted that tau, conventionally viewed as a cytoskeletal protein, also shuttles to the nucleus and may interact with nucleolar components, but the consequences of tau pathology for nucleolar homeostasis remained poorly charted territory.

To map that territory, the team used two complementary cellular systems: human neuroblastoma-derived SH-SY5Y cells engineered to express mutant tau, and induced pluripotent stem cell neurons generated from patients carrying disease-associated MAPT mutations. The researchers focused on three mutations known to cause familial forms of frontotemporal dementia and related tauopathies: P301S, one of the most widely studied mutations in tau transgenic models; S305N, which alters a critical phosphorylation-sensitive region; and the splice-site mutation IVS 10+16, which disrupts the normal ratio of tau isoforms by promoting inclusion of exon 10. Across both models, the team found that tau localised to the nucleolus, and that the disease-associated mutations were consistently associated with greater accumulation of tau within this structure compared with cells expressing the normal protein.

Using high-content imaging, an automated microscopy approach that quantifies features across thousands of cells, the researchers documented structural consequences of this mutant tau accumulation. Nuclei and nucleoli in cells expressing mutant tau were measurably enlarged, and key molecular markers drawn from all three canonical nucleolar sub-compartments, the fibrillar centre, the dense fibrillar component and the granular component, were upregulated. In a healthy cell, expansion of these compartments and elevation of their marker proteins generally signal increased biosynthetic demand rather than shutdown, and the pattern pointed the investigators toward a provocative conclusion: mutant tau appeared to be revving up the nucleolus rather than simply poisoning it.

Functional assays reinforced that interpretation. Quantitative PCR measurements indicated increased transcription from the ribosomal DNA repeats, and staining with a nucleolar RNA-selective dye revealed enhanced ribosomal RNA processing, both consistent with an elevated nucleolar biosynthetic output in mutant tau-expressing cells. In other words, the cellular protein-factory was running hotter than it should. But hyperactivity of this kind carries a cost. Alongside the signs of increased rDNA transcription, the team detected a suite of markers associated with nucleolar stress and cell death: stabilisation of p53, activation of the executioner caspases 3 and 7, and positive results in TUNEL assays, which flag the DNA fragmentation characteristic of apoptosis. Mutant tau-expressing cells were, in effect, working themselves to death.

The most therapeutically intriguing finding came when the researchers pharmacologically throttled back the nucleolar engine. By inhibiting RNA polymerase I, the enzyme responsible for transcribing ribosomal DNA, in the inducible SH-SY5Y model, they were able to attenuate caspase 3/7 activity. This result supports a functional link between the elevated rDNA transcriptional activity and the downstream apoptotic signalling, rather than the two phenomena merely co-occurring. If hyperactive ribosome biogenesis is genuinely contributing to cell death in mutant tau neurons, then RNA polymerase I emerges as a plausible point of intervention, a hypothesis that aligns with growing interest in nucleolar stress as a convergent mechanism across neurodegenerative diseases.

The study reframes tau in an unfamiliar light. For most of the modern era of dementia research, tau’s pathogenic identity has been tied to its misfolding and aggregation into paired helical filaments and neurofibrillary tangles, and to the toxic gain-of-function properties attributed to aggregated species. The new findings add a nuclear dimension to this picture, consistent with a body of recent evidence indicating that tau performs important roles within the nucleus and nucleolus, including reported interactions with DNA and effects on genome stability. If disease mutations perturb these nuclear functions early in the course of illness, nucleolar dysfunction could represent an upstream event that precedes, and potentially contributes to, the aggregation-centred pathology that dominates the late disease stage.

There are important caveats to keep in view. The experiments were conducted in cellular models, differentiated SH-SY5Y cells and iPSC-derived neurons, rather than in patient brain tissue or animal models, so the extent to which nucleolar hyperactivation operates in the living human brain with a MAPT mutation remains an open question. The authors also describe their work as identifying altered nucleolar homeostasis as a feature associated with mutant tau expression, a deliberately careful formulation that stops short of claiming causation for the broader disease process. The association between the mutations and increased nucleolar tau accumulation was consistent across the three variants examined, but the precise molecular mechanism by which mutant tau drives rDNA transcriptional hyperactivation, whether through direct effects on chromatin, on RNA polymerase I machinery, or on nucleolar stress pathways, has yet to be resolved.

Even with those limitations, the study opens several concrete lines of investigation. Nucleolar stress markers could serve as early biomarkers in cells derived from MAPT mutation carriers, potentially detectable before overt neurodegeneration. The finding that RNA polymerase I inhibition reduces caspase activation suggests that existing or in-development polymerase I inhibitors, some of which have been explored in oncology precisely because cancer cells depend on runaway ribosome biogenesis, might be repurposed or adapted for neurodegenerative contexts, though any such translation would need to reckon with the essential role of ribosome production in healthy neurons. The work also raises questions about whether other tauopathies, including sporadic Alzheimer’s disease, involve similar nucleolar perturbations even in the absence of MAPT mutations.

For a field that has poured enormous resources into anti-aggregation therapies with limited clinical success, the message that tau pathology may exert some of its damage through an entirely different cellular route is likely to resonate widely. The study, funded in part by the Rainwater Charitable Foundation, the Alzheimer’s Association, the Wellcome Trust and Alzheimer’s Research UK, was published open access, and its authors declare no competing interests. Whether targeting the nucleolus will ultimately yield new treatments for MAPT-linked frontotemporal dementia is far from settled, but the research makes a compelling case that the quiet factory at the heart of the nucleus deserves a far louder voice in conversations about how tau mutations kill neurons.

Subject of Research: Effects of MAPT tau mutations on nucleolar function and ribosomal DNA transcription in cellular models of frontotemporal dementia

Article Title: MAPT mutations are associated with rDNA transcriptional hyperactivation and nucleolar stress in cellular models

Article References: Muhammad, Z., Gu, Y., Kwairanga, S. H., Bailey, L. J., Khan, A., Nasser, M., Aljarrah, D., Barri, M., Arber, C., Wray, S., Serpell, L. C., Karch, C. M., & Maina, M. B. (2026). MAPT mutations are associated with rDNA transcriptional hyperactivation and nucleolar stress in cellular models. Translational Psychiatry. https://doi.org/10.1038/s41398-026-04484-7

Image Credits: AI Generated

DOI: 10.1038/s41398-026-04484-7

Keywords: tau, MAPT, nucleolus, rDNA transcription, nucleolar stress, frontotemporal dementia, Alzheimer's disease, RNA polymerase I, p53, apoptosis, iPSC neurons, tauopathies

The findings come from the Cortisol and Stress in Alzheimer’s disease cohort, known as Co-STAR, which recruited 124 patients visiting the Karolinska University Hospital memory clinic in Stockholm between 2014 and 2017. None of the participants had dementia; 56 were diagnosed with subjective cognitive impairment and 68 with mild cognitive impairment, making them a population in which the earliest biological changes of Alzheimer’s disease can be observed before overt decline. The participants averaged 61.5 years of age, and nearly 60 percent were women.

What makes the study technically distinctive is its reliance on cerebrospinal fluid, drawn by lumbar puncture as part of routine Swedish memory clinic assessment. The researchers measured three canonical Alzheimer’s biomarkers: beta-amyloid 42, the form of amyloid whose levels drop in spinal fluid as the protein is sequestered into plaques in the brain; total tau, which rises with neurodegeneration; and phosphorylated tau at position 181, which tracks the accumulation of tangled tau filaments. Samples were centrifuged, frozen at minus 80 degrees Celsius, and analyzed with sandwich ELISA, with statistical transformations applied to correct for skewness and outliers.

Stress was assessed in two complementary ways. The 10-item Perceived Stress Scale captured how overwhelmed participants felt during the previous month, while a 16-item inventory recorded stressful life events across the entire life course, from bereavements to prolonged family illness. The life-event measure was further subdivided into recent events occurring within five years, non-recent events, acute events with sudden onset, and chronic stressors of extended duration. Insomnia symptoms were scored from three items of the Karolinska Sleep Questionnaire covering difficulty falling asleep, repeated nightly awakenings, and premature morning awakening, yielding a total score from 0 to 15.

The central result was an interaction. In linear regression models adjusted for age, sex, education, sleep medication use, and depressive symptoms, insomnia and lifetime stressful life event exposure interacted significantly in relation to cerebrospinal fluid amyloid 42. Among participants with low insomnia scores, greater stressor exposure was actually associated with higher amyloid 42 levels. But among those with moderate to high insomnia, greater stress exposure tracked with lower amyloid 42 levels, the signature of greater amyloid deposition in the brain. Similar interaction patterns emerged for chronic stressors, acute stressors, and non-recent events, with the association fading again at very high insomnia scores, producing a non-linear curve that the authors mapped across the full insomnia spectrum.

Notably, the interaction appeared only for amyloid. Neither total tau nor phosphorylated tau showed any significant interplay with insomnia, a pattern consistent with prior research linking sleep disturbance to amyloid but not tau in middle-aged and older adults. Because amyloid accumulation is believed to occur earlier in the disease process than tau pathology, the authors suggest that the combined effects of stress and poor sleep may operate at the earliest stages of Alzheimer’s development, a window when prevention efforts could still alter the trajectory.

The mechanistic story the researchers assemble is a two-pronged attack on amyloid homeostasis. On the production side, animal studies indicate that chronic stress dysregulates glucocorticoid hormones, shifting the cleavage of amyloid precursor protein away from a benign pathway and toward the amyloidogenic one that generates beta-amyloid. On the clearance side, sleep is when the glymphatic system, the brain’s waste-flushing network, is most active, and insomnia impairs the removal of amyloid and tau. Stress therefore increases amyloid supply while insomnia throttles its disposal, and the combination may push amyloid availability past what either factor alone would produce.

Neuroinflammation offers a third converging pathway. Amyloid and inflammation feed each other in a vicious cycle: rising amyloid triggers inflammatory responses that in turn promote further amyloid production and plaque formation. Chronic stress, particularly through dysregulated cortisol secretion, is known to promote the release of pro-inflammatory markers, while chronic sleep deprivation in animal models increases neuroinflammatory signals that predict plaque accumulation. The authors also point to the hippocampus, a structure central to regulating the hypothalamic-pituitary-adrenal stress axis, which has been shown to shrink in chronic insomnia. A sleep-deprived hippocampus may be unusually vulnerable to stress-axis dysregulation, potentially explaining why lifetime stressor exposure, rather than current perceived stress, showed the strongest interactions.

The study also probed sex differences, given well-documented disparities in how men and women experience stress, sleep disturbance, and Alzheimer’s risk. When the analyses were stratified by sex, the direction of the interactions remained consistent in both groups, though statistical power was limited. Intriguingly, the overall association between stressful life events and amyloid 42 appeared to run in opposite directions in men and women, with greater stressor exposure tending toward higher amyloid 42 in men and lower levels in women. The authors urge caution here, but note that animal research and human imaging studies, including one finding that elevated cortisol was linked to greater amyloid deposition specifically in postmenopausal women, support the idea that sex hormones shape the physiological stress response in ways relevant to Alzheimer’s pathology.

The researchers are careful about the limits of their evidence. The design was cross-sectional, so reverse causation cannot be excluded: emerging brain pathology may itself disturb sleep and amplify perceived stress, particularly in a memory clinic population. Stress and insomnia were self-reported, leaving room for recall bias, and the sample of 124 was too small to confirm sex differences statistically. Longitudinal studies beginning before cognitive decline, ideally incorporating objective measures such as actigraphy and diurnal cortisol, are the necessary next step, though the authors caution that cortisol is itself altered by insomnia, complicating such designs. Still, the implications are striking. The 2024 Lancet Commission estimates that up to 45 percent of dementia cases could be delayed or prevented by addressing 14 modifiable risk factors, and this study adds a crucial nuance: risk factors do not act in isolation. Treating insomnia, a common and underdiagnosed condition in older adults, may matter most precisely for those carrying heavy burdens of life stress, suggesting that combination approaches to dementia prevention could outperform any single intervention.

Subject of Research: Interaction between insomnia symptoms and chronic stress exposure in relation to cerebrospinal fluid Alzheimer's disease biomarkers

Article Title: Insomnia symptoms and stress exposure interact in relation to Alzheimer’s disease biomarkers

Article References: Holleman, J., Kåreholt, I., Näsholm, M. S., Sørensen, C., Hagman, G., Aspö, M., Kivipelto, M., Solomon, A., & Sindi, S. (2026). Insomnia symptoms and stress exposure interact in relation to Alzheimer’s disease biomarkers. Journal of Neurology, 273(10), Article 560. https://doi.org/10.1007/s00415-026-14102-7

Image Credits: AI Generated

DOI: 10.1007/s00415-026-14102-7

Keywords: Alzheimer's disease, insomnia, chronic stress, beta-amyloid, tau, cerebrospinal fluid biomarkers, glymphatic system, stressful life events, memory clinic, dementia prevention, neuroinflammation, Karolinska Institutet

The Golgi apparatus is best known as the processing and dispatch center of the secretory pathway. Proteins manufactured in the endoplasmic reticulum pass through its stacked membrane cisternae, where they are chemically modified, most notably through glycosylation, the attachment of sugar chains, and then sorted to their correct destinations, whether the plasma membrane, secretory vesicles, or lysosomes. The organelle also manufactures key lipids such as sphingomyelin and glycosphingolipids, participates in autophagosome formation, and runs its own quality-control degradation pathways. In other words, the Golgi sits at the crossroads of protein and lipid homeostasis, which is precisely why its failure could ripple through nearly every cellular process implicated in neurodegeneration.

That failure is not hypothetical. Postmortem studies of Alzheimer’s brains have long revealed fragmented, atrophied Golgi structures in affected neurons. More strikingly, when researchers expressed the amyloid precursor protein Swedish mutant in cells, the Golgi fragmented, and restoring Golgi architecture by expressing the structural proteins GRASP65 and GRASP55 dramatically reduced amyloid-beta production. In induced pluripotent stem cell-derived neurons from patients with sporadic Alzheimer’s disease, the fragmented Golgi phenotype persisted and, crucially, appeared before amyloid and tau pathology developed, suggesting that Golgi breakdown may be one of the earliest cellular events in the disease rather than a late consequence of it.

The strongest new argument for the Golgi’s relevance comes from large-scale human data. When the authors surveyed genetic studies, a striking pattern emerged: multiple independent analyses keep nominating Golgi-related genes as Alzheimer’s risk factors. An RNA-sequencing analysis found that Golgi-related gene ontology terms were elevated both in patients and in people with high polygenic risk scores for the disease, particularly in the temporal cortex. An X-chromosome-wide association study identified SLC9A7, a sodium/proton exchanger concentrated in the trans-Golgi network that maintains the organelle’s acidity, as the only genome-wide significant risk locus. Because Golgi luminal pH governs protein modification, glycosylation, and trafficking, its disruption could derail amyloid precursor protein processing among many other consequences.

Other risk genes reinforce the same theme. SORL1 and SORCS1, both well-established genetic risk factors, encode sortilin-family receptors that shepherd the amyloid precursor protein back to the trans-Golgi network, keeping it away from the endosomes where amyloidogenic cleavage predominates. Adaptor protein 4 complex genes AP4M1 and AP4E1, flagged by enhancer mapping of genome-wide association loci, regulate the precursor protein’s delivery to endosomes. A protective variant in NSF, a gene essential for Golgi reassembly and vesicle fusion, was identified in whole-exome sequencing of patients lacking the ApoE4 allele, hinting that Golgi integrity itself may confer resilience. Machine learning analysis of European GWAS data proposed COG7, a subunit of the complex that maintains Golgi structure and glycosylation, as a new risk gene, and multiancestry proteomic analyses independently nominated COG7, the trans-Golgi metalloprotease CPD, and the retrograde trafficking proteins SNX1, SNX32, and STX6 as candidate causal proteins.

Proteomics adds a second layer of evidence. A landmark 2022 study of more than 500 human brain samples found that Golgi and protein transport module signatures were reduced in asymptomatic Alzheimer’s brains and diminished further in symptomatic cases, correlating with cognitive scores. Perhaps most intriguingly, the extracellular matrix protein repertoire, the matrisome, showed the most prominent proteomic changes in the disease that were invisible at the RNA level, implying that post-translational modifications are the real driver. Since matrix proteins such as proteoglycans and collagen are extensively processed and glycosylated within the Golgi before secretion, Golgi dysfunction offers a mechanistically coherent explanation for this transcriptome-proteome discordance, and matrisome proteins are known to colocalize with amyloid plaques.

A 2024 glycomics study sharpened the picture further by mapping the N-glycan landscape of Alzheimer’s brains. The most altered sugar structures, sialylated and highly branched forms, are built inside the Golgi, and the affected glycoproteins clustered at synapses and the cell surface. Glycoform signatures tied to disease status involved L1CAM and NPTX1, markers of synaptic plasticity and synaptic loss, as well as ATP1B1, a subunit of the sodium-potassium pump essential for neural signaling. Expression of several Golgi-resident glycosylation enzymes, including MAN2A1, MGAT1, and members of the B3GALT, B4GALT, ST6GAL, and ST8SIA families, was altered across multiple brain regions, consistent with a systematic breakdown of Golgi-dependent protein modification that could directly undermine synapses.

Lipid biology supplies a third pillar. The Golgi is the primary site of ceramide processing through glucosylceramide synthase, whose levels fall in Alzheimer’s brains in correlation with ceramide accumulation, a lipid that promotes amyloid-beta production, oxidative stress, and neuronal death. The Golgi-localized enzyme neutral sphingomyelinase 2 drives the secretion of extracellular vesicles that can spread pathological tau between cells; inhibiting it reduced tau propagation and neurodegeneration in mouse models, and neuronal deletion of the gene reduced amyloid-beta production. Meanwhile, the oxysterol-binding protein OSBP1, which exchanges cholesterol and PI4P between the trans-Golgi network and the endoplasmic reticulum at membrane contact sites, regulates cholesterol distribution, mitochondrial fission, and retrograde trafficking, and its knockdown increased amyloidogenic processing of the amyloid precursor protein, linking Golgi-managed cholesterol homeostasis directly to plaque biology.

The authors synthesize these threads into four candidate pathogenic mechanisms. First, Golgi fragmentation may disrupt the normal segregation of the amyloid precursor protein and its processing enzymes, increasing their contact and boosting amyloid-beta generation, possibly even within the Golgi itself. Second, impaired trafficking between the Golgi and the endolysosomal system would trap the precursor protein in endosomes while starving lysosomes of properly sorted enzymes, simultaneously raising amyloid production and lowering its clearance. Third, defective glycosylation would alter countless proteins, including the amyloid precursor protein itself, whose O-glycosylation influences its trafficking and cleavage. Fourth, lipid dyshomeostasis would feed back on Golgi membrane integrity, creating a self-reinforcing vicious cycle that also damages mitochondria and the endoplasmic reticulum. Upstream triggers, including aging, DNA damage, oxidative stress, and neuronal hyperexcitability, as well as amyloid-beta and tau themselves, can all induce Golgi fragmentation, closing the loop.

Therapeutically, the possibilities are still largely conceptual but tantalizing. Restoring Golgi structural integrity, for example through nonphosphorylatable GRASP55/65 variants, could in principle ameliorate multiple disease processes at once. More targeted options include nSMase2 inhibitors, which have already shown benefits in Alzheimer’s mouse models; overexpression of SORL1, which redirects the amyloid precursor protein to the Golgi and lowers amyloid-beta output; and reinforcement of glycosylation or lipid balance through COG7, glucosylceramide synthase, or OSBP1. The authors are candid about the caveats: causality between Golgi dysfunction and Alzheimer’s pathogenesis has not been rigorously established, most evidence comes from familial disease models rather than the sporadic form that accounts for roughly 90 percent of cases, and because the Golgi handles so much cellular traffic, interventions could carry pleiotropic side effects. Still, with anti-amyloid antibodies delivering only modest clinical benefit, the review makes a compelling case that keeping this cellular post office running smoothly may be one of the most underexplored strategies for halting the disease, and that the humble Golgi apparatus deserves a central seat at the Alzheimer’s research table.

Subject of Research: The role of Golgi apparatus dysfunction in Alzheimer's disease pathogenesis and therapy

Article Title: Golgi dysfunction in Alzheimer disease: from human multiomic signatures to therapeutic targets

Article References: Song, J., Lee, S.-J., & Mook-Jung, I. (2026). Golgi dysfunction in Alzheimer disease: from human multiomic signatures to therapeutic targets. Experimental & Molecular Medicine. https://doi.org/10.1038/s12276-026-01851-8

Image Credits: AI Generated

DOI: 10.1038/s12276-026-01851-8

Keywords: Alzheimer's disease, Golgi apparatus, amyloid-beta, tau, glycosylation, lipid metabolism, SORL1, trans-Golgi network, multiomics, neurodegeneration, endolysosomal trafficking, therapeutic targets

The evidence they marshal for the inadequacy of the current model is stark. Therapeutic efforts have long targeted the defining pathological features of dementia: the aggregation of misfolded proteins such as amyloid-β and tau, the loss of synapses, and the death of neurons. Recent drugs that effectively eliminate amyloid plaques from the brain confer only modest benefit, slowing disease progression by roughly 20 to 30 percent in a selected clinical trial population. The authors argue that this discordance between successful removal of the molecular target and minimal-to-modest improvement in functional outcomes raises a fundamental question. If clearing amyloid and tau does not rescue cognition, are these protein deposits truly the primary drivers of dementia, or are they downstream footprints of something deeper?

Their answer lies in metabolism. The human brain is an extraordinarily expensive organ to run. Although it accounts for only a small fraction of body weight, it consumes a disproportionate share of the body’s total energy, and it has essentially no reserve and minimal tolerance for fluctuation. Its function depends on the continuous, precisely regulated delivery and utilization of oxygen and metabolic substrates through a highly efficient and plastic vascular network. Even modest energy dysregulation, well within the range produced by common metabolic disorders, can create a chronic cerebral energy deficit. The immediate consequence is not cell death but the activation of stress-response mechanisms, including the unfolded protein response and the integrated stress response. These responses are initially compensatory, but over time they trigger a gradual erosion of synaptic function and neuronal network integrity.

The epidemiological evidence supporting a systemic view is substantial. Declining metabolic and vascular health across the life course closely parallels cognitive decline. Conditions that impair systemic energy homeostasis, particularly during midlife, including diabetes, hypertension, and dyslipidemia, are consistently associated with an increased risk of dementia, and they are also linked to both Alzheimer’s disease pathology and cerebrovascular damage. Conversely, factors associated with efficient energy production and delivery, such as physical activity and cardiovascular fitness, are among the most robust protective factors against brain aging and neurodegeneration. A healthy brain, the authors contend, requires the integrity of the physiological systems that regulate energy production and distribution throughout the body, not merely the absence of pathology within the brain itself.

Mechanistically, multiple aging processes converge on this energetic axis. Brain insulin resistance reduces the efficiency with which cells utilize available energy. Vascular dysfunction limits the delivery of oxygen and metabolic substrates to tissue. Chronic inflammation disrupts homeostatic signaling while simultaneously increasing metabolic demand. Together, these alterations create a state of energetic insufficiency that compromises neuronal function, impairs resilience to stress, and ultimately contributes to the development of dementia. The vascular system occupies a central position at this intersection, sitting precisely where systemic energy dysregulation meets neurodegeneration.

One of the most intriguing threads in the argument involves subtle signs of aging that seem, on the surface, unrelated to cognition. Deficits in sensorimotor function, such as slow gait, oculomotor impairment, and diminished olfaction, are early indicators of future cognitive decline. The authors suggest that these seemingly distinct aging phenotypes may share common systemic drivers, including inflammation, impaired lipid metabolism, vascular pathology, and compromised mitochondrial health. All are components of the system responsible for maintaining energy homeostasis, and that system progressively loses efficiency with age and disease, narrowing the margin within which organs can function. The brain, operating closest to that margin, is the first place the narrowing becomes clinically visible.

Chronic energy insufficiency also has downstream consequences for tissue maintenance and repair that may feed back into the problem. A sustained deficit in cellular energy availability promotes cellular senescence, impaired proteostasis, and remodeling of the extracellular matrix. Senescent cells alter the composition and physical properties of the extracellular environment, favoring fibrosis, collagen deposition, and cross-linking. These changes increase tissue stiffness, disrupt microvascular function, and impair perfusion and oxygen delivery, which in turn damages mitochondrial health and further erodes energy sufficiency. The authors describe this as a senescence-stiffening loop, a self-reinforcing cycle in which energy failure drives structural change and structural change deepens energy failure. Even the aging brain, generally considered less fibrotic than other organs, shows measurable changes in extracellular matrix composition, basement membrane thickening, and vascular stiffening, all of which contribute to impaired neurovascular coupling and reduced adaptability of cerebral blood flow.

This framework offers a potential resolution to one of the most stubborn paradoxes in Alzheimer’s research: why some resilient individuals with substantial neuropathology remain cognitively intact while others with far less pathology develop severe impairment. The authors propose that the difference may lie in the organism’s capacity to maintain energy homeostasis. Recent work supports this idea, showing that preserved mitochondrial bioenergetics distinguishes asymptomatic individuals from symptomatic ones in the presence of Alzheimer’s disease pathology. In other words, amyloid and tau may set the stage, but the body’s energetic resilience determines whether the play is performed. The defining features of dementia, from protein aggregation to synaptic loss to neuronal death, may represent downstream manifestations of prolonged energetic insufficiency in the most energy-dependent organ in the body.

The clinical implications, if the hypothesis is correct, are profound. Treating dementia by targeting isolated molecular features within the brain may be fundamentally misdirected, because a failing energy-regulation system cannot be rescued by correcting a single downstream lesion. Prevention and treatment must instead focus on preserving energetic resilience across the entire life course, maintaining the capacity to efficiently produce, distribute, and utilize energy. The consistent link between midlife metabolic and vascular health and preserved brain function into late life suggests that the brain may track the body’s ability to meet its energy demands decades before any cognitive symptom appears. That would reframe midlife blood pressure, glucose, and lipid control not merely as heart disease prevention but as dementia prevention.

The authors are careful to note what their argument does not claim. It does not imply that brain-specific processes are irrelevant, nor that all dementias are the same. Genetic forms of dementia and distinct neurodegenerative mechanisms clearly exist, and etiologically distinct forms may represent special cases within a broader framework in which systemic energetic failure is the dominant driver of late-life cognitive impairment. But the broader message is hard to dismiss: the brain, by operating at the very limits of energetic stability, is simply where the body’s slow systemic failure becomes impossible to ignore. If the hypothesis withstands experimental scrutiny, the search for dementia’s cure may move out of the brain and into the bloodstream, the vasculature, and the mitochondria that power every cell in the body.

Subject of Research: Systemic energy dysregulation as a proposed primary mechanism of dementia

Article Title: Is dementia really a brain disease?

Article References: Tian, Q., Walker, K. A., & Ferrucci, L. (2026). Is dementia really a brain disease?. PLOS Aging and Health, 1(3), e0000035. https://doi.org/10.1371/journal.page.0000035

Image Credits: AI Generated

DOI: 10.1371/journal.page.0000035

Keywords: dementia, Alzheimer's disease, energy metabolism, mitochondria, vascular health, brain aging, insulin resistance, inflammation, amyloid-beta, tau, cellular senescence, neurodegeneration