The clearest thread running through the collection concerns inflammation, and in particular whether modern diabetes drugs do more than lower glucose. In one of the largest analyses included, Alrasheed and colleagues pooled evidence from 40 randomized controlled trials covering 6,029 participants and found that glucagon-like peptide-1 receptor agonists, the drug class behind blockbuster therapies such as semaglutide, significantly reduced major inflammatory biomarkers, most notably C-reactive protein and tumor necrosis factor-alpha. That effect was observed beyond the drugs’ established glycemic control, supporting the idea that part of their cardiovascular benefit may stem from dampening chronic low-grade inflammation rather than from sugar lowering alone. The finding adds mechanistic weight to clinical observations that these agents protect organs in ways that glucose numbers cannot fully explain.

Inflammation in diabetes is not uniform, however, and a second study underscored just how heterogeneous the immune landscape can be at the moment of diagnosis. Tleumagambetova and colleagues examined the balance between interleukin-1beta, a potent pro-inflammatory cytokine, and its natural brake, the interleukin-1 receptor antagonist, in adults newly diagnosed with diabetes. They found lower circulating levels of the receptor antagonist and a higher pro- to anti-inflammatory ratio in individuals who tested positive for islet autoantibodies, markers more often associated with autoimmune forms of the disease. The result suggests that immunometabolic heterogeneity exists right from disease onset, meaning that two patients with identical glucose profiles may sit on very different inflammatory trajectories and may require different therapeutic strategies.

Hypoxia, the cellular response to low oxygen, provides another critical link between metabolic stress and organ damage. In a systematic review and meta-analysis, Su and colleagues examined peripheral blood levels of hypoxia-inducible factor-1alpha, or HIF-1alpha, a master transcriptional regulator switched on when cells sense oxygen deprivation. They found associations between elevated circulating HIF-1alpha and adverse metabolic indices reflecting pancreatic beta-cell dysfunction and insulin resistance. In a companion meta-analysis, the same team extended the analysis to HIF-1alpha alongside sirtuin 1, an NAD-dependent deacetylase central to cellular stress resistance, and vascular endothelial growth factor, the principal driver of new blood vessel formation, revealing altered hypoxic and vascular adaptive responses across diabetic complications.

The authors of the editorial caution, however, that these findings must be interpreted carefully. Circulating markers of hypoxic signaling do not necessarily mirror what is happening inside target tissues, where HIF-1alpha may behave very differently depending on cell type and disease stage. Distinguishing blood-borne signals from tissue-specific signaling is, they argue, an essential next step if researchers hope to understand whether the hypoxic response in diabetes is a protective adaptation that has gone awry or a direct contributor to pathology. The distinction matters enormously for drug development, because blindly activating or suppressing HIF-1alpha could do harm if the biology is misread.

At the cellular level, the collection homes in on mitochondria, the power plants whose dysfunction sits at the intersection of metabolic stress and organ injury. Tamaki and colleagues investigated bone morphogenetic protein 4, or BMP4, a signaling molecule previously associated with scarring and extracellular matrix production in diabetic nephropathy, the kidney complication that remains a leading cause of dialysis worldwide. They demonstrated that BMP4 stimulation led to downregulation of Parkin, a protein responsible for tagging damaged mitochondria for removal, and to impaired mitochondrial homeostasis in mesangial cells, the support cells of the kidney’s filtering units. Crucially, both ALK inhibition and Parkin overexpression ameliorated several of these mitochondrial abnormalities, extending BMP4’s role beyond matrix production into the realm of mitochondrial quality control.

Not every intervention tested in the collection produced clean answers, and that may be its most scientifically honest feature. Kubo and colleagues compared the selective lipid-lowering agent pemafibrate against the omega-3 fatty acid eicosapentaenoic acid in patients with both type 2 diabetes and hypertriglyceridemia. Pemafibrate achieved a greater reduction in malondialdehyde-modified low-density lipoprotein, a chemically altered cholesterol particle implicated in atherosclerosis. Yet urinary 8-hydroxy-2′-deoxyguanosine, a marker of oxidative damage to DNA, and high-sensitivity C-reactive protein did not differ significantly between the two treatments. The takeaway, according to the editors, is that oxidative stress is biologically heterogeneous, and that reading a single biomarker as a proxy for the body’s entire redox state invites misleading conclusions.

Nutrition and environment also emerge as modifiable levers. Wang and colleagues applied machine-learning approaches to dietary oxidative balance, the ratio of antioxidant to pro-oxidant components in the diet, and identified vitamin E, magnesium, and beta-carotene among the factors associated with renal impairment defined by the urinary albumin-to-creatinine ratio, a standard clinical measure of kidney damage. Exploratory experiments implicated AKT-related signaling, a central growth and survival pathway, as a possible mechanistic mediator. On the environmental front, Zhang and colleagues reported interactions between temperature, humidity, and tongue color in patients with diabetes, with the associations particularly pronounced among individuals with cardiovascular complications, hinting that environmental stress may interact with impaired microcirculatory adaptation in measurable ways.

The clinical stakes of these molecular networks are laid bare in two studies of established complications. Rashwan and colleagues, studying 387 patients with diabetic peripheral neuropathy, identified smoking, a history of foot ulceration or amputation, and advanced chronic kidney disease as the factors most strongly associated with loss of protective sensation, the deficits that precede the foot ulcers and amputations that make diabetes one of the leading causes of limb loss worldwide. Meanwhile, Srithongchai and colleagues reviewed the advanced glycation end-product and its receptor, the AGE-RAGE axis, as a pathogenic signaling network. Membrane-bound RAGE, they argue, serves as an interface connecting carbonyl and oxidative stress with inflammatory activation, while soluble RAGE isoforms may act as decoy receptors that blunt the damage. Importantly, the review reframes RAGE’s physiological function as the selective modulation of pathogenic signaling rather than indiscriminate receptor activity, suggesting that future therapies should aim for precision rather than blanket blockade.

Taken together, the ten contributions portray diabetic complications as products of an interconnected network operating across tissues and disease stages rather than the work of any single pathway. Metabolic overload, oxidative and carbonyl stress, inflammation, hypoxic responses, mitochondrial dysfunction, environmental influences, and impaired adaptive mechanisms all feed into one another, which is why changes in any individual molecular marker cannot be interpreted in isolation. The editors argue that future research should focus on defining the molecular switches that determine whether stress responses remain adaptive or turn pathogenic, on integrating complementary biomarkers across biological compartments, and on testing whether selective modulation of these pathways can translate into genuine prevention of organ injury. If successful, such mechanism-based strategies could move the management of type 2 diabetes beyond the glucose meter, toward treating the web of stress and inflammation that ultimately destroys organs.

Subject of Research: Oxidative stress and inflammatory pathways driving organ complications in type 2 diabetes

Article Title: Editorial: Oxidative stress and inflammation in type 2 diabetes: pathways to organ complications

Article References: Editorial: Oxidative stress and inflammation in type 2 diabetes: pathways to organ complications. (n.d.). https://doi.org/10.3389/fcdhc.2026.1976753

Image Credits: AI Generated

DOI: 10.3389/fcdhc.2026.1976753

Keywords: type 2 diabetes, oxidative stress, inflammation, GLP-1 receptor agonists, HIF-1alpha, mitochondrial dysfunction, diabetic nephropathy, RAGE, diabetic neuropathy, biomarkers, AGEs, diabetic complications

The study, led by Peipei Wu, Jingru Huan, and Chengliang Liu together with colleagues at Anhui Medical University, integrated bulk RNA sequencing with single-cell RNA sequencing to dissect pulmonary hypertension at unprecedented resolution. The rationale is elegant. Bulk RNA sequencing measures the average gene expression across a mixed tissue sample and has long been used to find differentially expressed genes in the disease, but lung vascular tissue contains many cell types, including endothelial cells, smooth muscle cells, and infiltrating immune cells, so the technique cannot say which cell is doing what. Single-cell RNA sequencing resolves that heterogeneity cell by cell, yet it is often limited by small sample sizes and shallow sequencing depth. Merging the two approaches allows researchers to pull robust disease-associated genes from the global transcriptomic landscape and then anchor them to specific cell types.

The team began with the single-cell side of the analysis, mining the public dataset GSE210248, which contains pulmonary vascular tissue from three pulmonary hypertension patients and three healthy controls. After rigorous quality control, in which cells with too few detected genes or excessive mitochondrial gene content were discarded, the researchers identified 19,582 genes and selected the top 1,500 highly variable ones for downstream analysis. Using principal component analysis and uniform manifold approximation and projection, a dimensionality-reduction technique that lets scientists visualize high-dimensional data in two dimensions, they clustered the cells into 14 distinct populations. These included smooth muscle cells, endothelial cells, fibroblasts, macrophages, monocytes, several T cell subsets, natural killer cells, B cells, dendritic cells, adipocytes, epithelial cells, and hematopoietic stem cells, painting a remarkably complete picture of the pulmonary vascular microenvironment.

Next came the question of who talks to whom. Using the CellChat tool, which infers communication networks from ligand-receptor expression patterns, the researchers mapped the interactions among all 14 cell types. Smooth muscle cells emerged as a dominant hub of intercellular communication. Endothelial cells interacted most strongly with T cells, epithelial cells with macrophages, and smooth muscle cells with dendritic cells. Among the specific ligand-receptor pairs mediating this crosstalk, two stood out: Annexin A1 binding to formyl peptide receptor 1, which mediates communication between smooth muscle cells and monocytes, and complement component 3 binding to its receptor C3AR1, which mediates smooth muscle cell-macrophage communication. These findings dovetail with growing evidence that immune-stromal paracrine loops drive pulmonary vascular remodeling. Notably, elevated plasma Annexin A1 has previously been linked to reduced survival in pulmonary arterial hypertension, and complement C3 sits at the intersection of all three complement pathways, coordinating endothelial activation, smooth muscle phenotype switching, immune cell recruitment, and platelet activation.

Because pulmonary artery smooth muscle cells are considered central players in the disease, the researchers then applied high-dimensional weighted gene co-expression network analysis, or hdWGCNA, specifically to the smooth muscle cell population. This method groups genes that rise and fall together across cells, revealing functional modules rather than single genes. With the soft threshold optimized to five to ensure a scale-free network, hierarchical clustering partitioned the smooth muscle transcriptome into eight co-expression modules, four of which, labeled M2, M6, M7, and M8, showed significant and specific enrichment in smooth muscle cells. Within these modules, S100A10, ANXA2, RPL13A, and RPL13 emerged as key network nodes. Gene Ontology analysis of the four module gene sets revealed strong enrichment in extracellular matrix organization, extracellular structure organization, and related processes, while Kyoto Encyclopedia of Genes and Genomes pathway analysis pointed to the TGF-beta signaling pathway, amino sugar and nucleotide sugar metabolism, and the HIF-1 signaling pathway, all well-established drivers of pulmonary vascular pathology.

With the single-cell landscape mapped, the team turned to the bulk side, pooling three independent transcriptomic cohorts from the Gene Expression Omnibus: GSE113439 with 15 patients and 11 controls, GSE53408 with 12 patients and 11 controls, and GSE117261 with 58 patients and 25 controls. After correcting batch effects across the datasets, they identified differentially expressed genes using a log fold-change threshold of 0.585 and an adjusted p value below 0.05. They then calculated the area under the receiver operating characteristic curve for each gene, a standard measure of diagnostic power, and retained 19 genes with an AUC above 0.7. Among these, MFGE8, a gene encoding milk fat globule-epidermal growth factor-8, achieved an AUC of 0.81 on its own, demonstrating strong standalone diagnostic performance.

To squeeze the most diagnostic value from these candidates, the researchers built multiple machine learning models, splitting the data into training and test sets at a 7:3 ratio. A partial least squares model performed best, achieving an AUC of 0.895, and it distilled the disease signature down to five hub genes: C1R, MFGE8, S100A11, PCOLCE2, and SFRP2. Critically, the model held up outside its training data. In two external validation cohorts, GSE15197 and GSE24988, the model achieved AUCs of 0.756 and 0.712 respectively, confirming that the five-gene signature generalizes across independent patient groups. The team also mapped the chromosomal locations of the five genes and probed their relationships with the immune microenvironment using the CIBERSORT algorithm, finding that S100A11 and PCOLCE2 correlated positively with M0 macrophages, SFRP2 with activated CD4 memory T cells and plasma cells, and MFGE8 with monocytes, consistent with its known role as a bridging molecule in phagocytosis.

Single-sample gene set enrichment analysis added another layer of biological insight. Comparing the HALLMARK pathway collection between patients and controls revealed that angiogenesis and epithelial-mesenchymal transition signatures were significantly upregulated in pulmonary hypertension, both closely tied to endothelial dysfunction and smooth muscle hypertrophy. Each hub gene carried its own pathway fingerprint: C1R was associated with xenobiotic metabolism and glycolysis, SFRP2 with epithelial-mesenchymal transition and coagulation, S100A11 with reactive oxygen species and IL-6/JAK-STAT3 signaling, and PCOLCE2 with oxidative phosphorylation. These associations underscore the metabolic reprogramming, from glycolysis to altered mitochondrial respiration, that sustains the hyperproliferative phenotype of pulmonary artery smooth muscle cells in the disease.

The most compelling part of the study is its experimental validation. The team cultured human pulmonary artery smooth muscle cells under normal oxygen or under 1 percent oxygen for 24 hours to mimic the hypoxic conditions of pulmonary hypertension. Reverse transcription quantitative PCR and western blotting showed that MFGE8, SFRP2, S100A11, and PCOLCE2 were all upregulated under hypoxia, with immunofluorescence confirming cytoplasmic localization. When the researchers silenced each gene with small interfering RNAs, both cell counting kit-8 assays and EdU incorporation assays showed that knocking down any of the four genes significantly inhibited smooth muscle cell proliferation. Digging deeper into mechanism, the team found that SFRP2 and S100A11 were positively correlated with HIF-1alpha, the master transcriptional regulator of the hypoxic response. Silencing either gene partially reduced HIF-1alpha protein levels, and, strikingly, overexpressing HIF-1alpha could partially rescue the proliferation slowdown caused by S100A11 or SFRP2 knockdown, placing these genes squarely within the hypoxia-driven growth circuitry of the diseased vasculature.

The authors are candid about the limitations. The analysis relies on publicly available datasets that, despite careful batch correction, still require validation in prospective cohorts. Subclustering of smooth muscle cells was not possible because too few cells were available, and the in vitro work was confined to acute hypoxia in a single cell type, leaving the genes’ effects on hemodynamics and right ventricular function untested in living animals. C1R, in particular, showed no differential expression under acute hypoxia, likely because it is expressed mainly by immune or endothelial cells or responds to chronic inflammatory rather than hypoxic signals. Even so, the study delivers a coherent new model of pulmonary hypertension in which smooth muscle cells act as central orchestrators of vascular remodeling, wired into the immune system through Annexin A1 and complement signaling and driven to proliferate by a hypoxia-HIF-1alpha axis involving MFGE8, SFRP2, S100A11, and PCOLCE2. If future work confirms these genes in patients, the five-gene signature could become both an early diagnostic blood test and a roadmap for the targeted therapies that pulmonary hypertension patients still desperately need.

Subject of Research: Integrative bulk and single-cell transcriptomic analysis of pulmonary hypertension identifying smooth muscle cell signaling hubs and diagnostic gene biomarkers

Article Title: Key genes and pathways of pulmonary hypertension identified by integrating bulk and single-cell RNA sequencing

Article References: Wu, P., Huan, J., Liu, C., Jin, H., Wang, R., Wang, Y., Cao, C., & Zhang, B. (2026). Key genes and pathways of pulmonary hypertension identified by integrating bulk and single-cell RNA sequencing. iScience, 29(11), Article 117846. https://doi.org/10.1016/j.isci.2026.117846

Image Credits: AI Generated

DOI: 10.1016/j.isci.2026.117846

Keywords: pulmonary hypertension, single-cell RNA sequencing, bulk RNA sequencing, smooth muscle cells, hdWGCNA, machine learning, HIF-1alpha, biomarkers, vascular remodeling, TGF-beta signaling, immune infiltration, diagnostic gene signature

Mesenchymal stem cells, or MSCs, are the workhorses of cell-based repair. Harvested from bone marrow or fat, they secrete factors that calm inflammation, encourage angiogenesis, and limit the destructive remodeling that follows a myocardial infarction. Yet clinical trials in ischemic heart disease have produced frustratingly inconsistent results, and the new study points to a likely culprit: senescence. Donor age and the replicative stress of the large-scale expansion needed to produce clinically useful cell numbers both push MSCs into a senescent state, robbing them of the proliferative capacity, migratory behavior, and paracrine output that make them therapeutic in the first place. The harsh, oxygen-starved environment of an infarcted heart can then induce premature senescence in the transplanted cells themselves, further eroding any benefit.

The researchers began with an epidemiological puzzle. Asprosin, encoded by the FBN1 gene that also produces the structural protein fibrillin-1, is known to rise with obesity, driving hepatic glucose release in younger organisms. But when the team measured circulating asprosin in aged mice, they found that despite significant age-related weight gain, levels failed to rise, and aged animals even developed the impaired glucose tolerance that young obese mice display alongside high asprosin. Public transcriptomic datasets revealed why: Fbn1 expression declines with age across a remarkable range of tissues, including white adipose tissue, heart, lung, skeletal muscle, and skin, with the attrition more pronounced in males. Western blotting confirmed matching reductions in asprosin protein in fat, heart, and muscle across young, middle-aged, and old mice.

The human evidence proved equally compelling. In a cohort of 95 normal-weight men, recruited with an a priori power calculation to control for the confounding effect of adiposity, fasting plasma asprosin showed a significant negative correlation with age, with a Spearman coefficient of -0.374. Aging, in other words, appears to override the adiposity-driven regulation that dominates asprosin levels in youth. Single-cell RNA sequencing data from mice, rats, and humans then revealed something unexpected: MSCs, not mature adipocytes, are the dominant FBN1-expressing cell type across fat, muscle, and bone marrow. Pseudotime trajectory analysis showed FBN1 expression falling steadily as multipotent progenitors commit to differentiated lineages, tying the hormone directly to stemness itself. Both chronically aged and acutely senescent MSCs, the latter produced by hydrogen peroxide treatment, showed coordinated declines in Fbn1 transcription, intracellular asprosin, and secreted asprosin.

To test whether asprosin actively governs senescence rather than merely tracking it, the team built CRISPR-Cas9 lentiviral vectors targeting the furin cleavage site within the Fbn1 gene, selectively ablating the hormone while preserving fibrillin-1’s structural role. Asprosin-deficient young MSCs proliferated poorly and, when challenged with hydrogen peroxide, accumulated in the G1 phase of the cell cycle, stained heavily for senescence-associated beta-galactosidase, lost clonogenic potential, and under high oxidative stress underwent increased apoptosis. The mirror-image experiment was more dramatic: overexpressing human asprosin in aged MSCs restored proliferation, pushed cells back into S phase, reduced senescence markers, and enhanced colony formation. Recombinant asprosin produced in human cells, at concentrations from 10 nanograms per milliliter up to 10 micrograms per milliliter without cytotoxicity, reproduced these effects across mouse bone marrow cells, mouse fat-derived cells, and human adipose-derived stem cells.

The mechanism traces through metabolism. Gene set enrichment analysis of asprosin-treated senescent MSCs showed activation of the PI3K-AKT and HIF-1 signaling pathways and a strong enrichment of glycolysis-related gene sets, with no change in oxidative phosphorylation. Seahorse metabolic flux assays confirmed that asprosin raised the extracellular acidification rate, basal glycolysis, and compensatory glycolytic capacity, while lactate production rose and was abolished by the glycolysis inhibitor 2-deoxyglucose. Asprosin upregulated the glucose transporter GLUT1 and rate-limiting enzymes including hexokinase 2 and the phosphofructokinases PFKL and PFKP. Pharmacological inhibition of AKT with MK2206 or of HIF-1alpha with KC7F2 blocked every one of these metabolic shifts, and either inhibitor, or 2-deoxyglucose, erased asprosin’s boosts to proliferation and migration. Notably, mTOR stayed inactive, indicating that asprosin works through a signaling route distinct from classical growth factor pathways. Intriguingly, the proangiogenic paracrine effect, driven by elevated VEGF-A and TIMP-1, depended on AKT-HIF-1 signaling but not on glycolysis itself.

That distinction between bioenergetics and gene regulation is where the study’s most novel layer emerges. Lactate, the end product of glycolysis, is now known to serve as a substrate for histone lactylation, a recently discovered post-translational modification in which lactate is covalently attached to lysine residues on histone proteins. The team showed that asprosin treatment increased global lysine lactylation and, specifically, lactylation of histone H3 at lysine 18, or H3K18la, in senescent MSCs, mirroring the effect of exogenous lactate. Blocking lactate production with sodium oxamate or inhibiting the p300 writer enzyme with A485 abolished both the H3K18la increase and the functional rejuvenation. CUT&Tag sequencing then mapped the epigenetic landscape: asprosin broadened H3K18la deposition genome-wide, and 70 percent of the genes it upregulated carried promoter-associated H3K18la marks. Among the targets were genes governing cell cycle progression and migration, and, critically, a network of DNA repair and replication fidelity genes, including Mcm8, Nucks1, Recql, Grwd1, and Foxp1, whose promoters gained H3K18la enrichment. When asprosin was knocked out, hydrogen peroxide-induced DNA double-strand breaks, marked by gamma-H2AX foci, worsened and repair faltered.

The therapeutic payoff came in a mouse model of acute myocardial infarction. Senescent MSCs transduced with an asprosin-overexpressing lentivirus, or with an empty vector, were injected into the infarct border zone. Immunofluorescent quantification on days 3 and 7 showed significantly higher retention of the asprosin-engineered cells. Over 28 days, mice receiving asprosin-overexpressing MSCs survived at higher rates than untreated infarct controls, while the empty-vector cells conferred no survival benefit. Echocardiography revealed improved left ventricular ejection fraction only in the asprosin group, which also showed reduced heart-to-lung and heart-to-body weight ratios, smaller fibrotic areas on Masson’s trichrome staining, and increased numbers of CD31-positive endothelial and alpha-SMA-positive smooth muscle cells in the peri-infarct zone, indicating robust new vessel formation.

The authors frame their intervention as a third way beyond existing anti-senescence strategies. Senolytics clear damaged cells, and NAD-boosting compounds offer generic metabolic support, but asprosin instead performs what they call functional reprogramming: it directly reverses the senescent state by activating a specific glycolysis-H3K18la axis, restoring a regenerative phenotype without deleting the cells or merely nourishing them. The team also showed that asprosin’s bioactivity depends on post-translational modifications present only in eukaryotic production systems, as bacterially derived protein failed to elicit the same transcriptional response, a caution for any future pharmaceutical development. Significant hurdles remain before clinical translation: the murine infarct model does not capture the comorbidities of human patients, lentiviral overexpression carries a theoretical insertional mutagenesis risk that local, cell-based delivery is designed to minimize, and the MSC-specific asprosin receptor has yet to be identified. Still, with efficacy demonstrated across species, tissue sources, and a broad safe concentration range, asprosin-engineered stem cells now stand as one of the most mechanistically complete rejuvenation strategies yet described, and a promising enhancement partner for the next generation of cardiac cell therapy.

Subject of Research: Asprosin-driven metabolic and epigenetic rejuvenation of senescent mesenchymal stem cells for cardiac repair after myocardial infarction

Article Title: Asprosin-driven metabolic-epigenetic rewiring attenuates mesenchymal stem cell senescence with therapeutic benefits for infarcted hearts

Article References: Zhang, Z., Wang, Z., Zhu, L., Chen, T., Chen, R., Wu, Z., Chen, J., Zhang, H., Wang, M., Liu, J., Hua, N., Hu, S., & Chen, Y. (2026). Asprosin-driven metabolic-epigenetic rewiring attenuates mesenchymal stem cell senescence with therapeutic benefits for infarcted hearts. Journal of Advanced Research, 88, 1055-1075. https://doi.org/10.1016/j.jare.2026.01.073

Image Credits: AI Generated

DOI: 10.1016/j.jare.2026.01.073

Keywords: asprosin, mesenchymal stem cells, senescence, histone lactylation, H3K18la, glycolysis, myocardial infarction, FBN1, epigenetics, cardiac repair, regenerative medicine, HIF-1alpha

The research, led by Taketo Ezaki and colleagues at Keio University, The Jikei University School of Medicine, and collaborating institutions across Japan, analyzed 66 tissue specimens from 33 glioblastoma patients. What makes the work exceptional is its longitudinal design. Japan is the only country where bevacizumab is approved for use at initial diagnosis, which allowed the team to collect neoadjuvant bevacizumab (neoBev) specimens—tumors removed after patients had already received the drug before surgery. The cohort included 15 bevacizumab-naive cases and 18 neoBev cases, alongside 33 refractory specimens gathered from salvage surgery and autopsy. Crucially, the refractory group included paired samples from the same patients at different treatment phases, enabling direct molecular comparison between the bevacizumab-responsive and bevacizumab-resistant states of individual tumors.

The team measured ANXA2 expression using quantitative real-time PCR on formalin-fixed paraffin-embedded tissue, normalizing against the housekeeping genes GAPDH and beta-actin and applying the comparative cycle threshold method. Protein localization was mapped with immunohistochemistry and triple-label immunofluorescence, staining for ANXA2 alongside the hypoxia marker hypoxia-inducible factor-1α (HIF-1α) and the stem cell marker CD133. The statistical centerpiece was a multivariate Cox proportional hazards model that adjusted for age, the number of temozolomide and bevacizumab cycles, extent of resection, and sex. Against this rigorous backdrop, one finding stood out with unusual clarity: high ANXA2 mRNA expression was an independent predictor of both shorter progression-free survival (hazard ratio 2.85, p = 0.028) and shorter overall survival (hazard ratio 3.12, p = 0.015).

The survival data became even more compelling when patients were stratified by both treatment and expression level. Within the neoBev group, patients with low ANXA2 expression achieved significantly longer progression-free survival than those with high expression (p = 0.034), and the same held true for overall survival (p = 0.004). In fact, the clinical benefit of neoadjuvant bevacizumab appeared to be restricted almost entirely to the low-ANXA2 subgroup. Among low-expressers, those treated with neoBev showed significantly longer progression-free survival than naive counterparts (p = 0.006). By contrast, the neoBev high-expression group fared significantly worse in overall survival than the naive high-expression group (p = 0.029), suggesting that elevated ANXA2 does not merely fail to respond to the drug—it actively counteracts its efficacy.

Why would this one protein carry such prognostic weight? The answer lies in its unusual dual role in tumor biology. ANXA2 sits upstream of the plasmin-MMP axis: it facilitates the activation of plasminogen, which in turn triggers matrix metalloproteinases MMP2 and MMP9, enzymes that degrade the extracellular matrix and clear the path for tumor invasion. At the same time, ANXA2 is deeply involved in angiogenesis, the very process bevacizumab is designed to suppress. It also participates in stemness, epithelial-mesenchymal transition, and hypoxia signaling. Unlike MMP2, MMP9, TIMP-1, or PAI-1, which each reflect a single component of matrix remodeling, ANXA2 functions as a hub connecting multiple invasion-related pathways, making it a potentially more reliable readout of the angiogenic-to-invasive transition that defines bevacizumab resistance.

The spatial analyses added a striking layer of biological detail. Immunohistochemistry revealed intense ANXA2 expression in the tumor vasculature and stroma at the glioblastoma leading edge—the invasive frontier where tumor cells fan out into surrounding brain tissue. Triple-label immunofluorescence showed ANXA2 co-localizing with HIF-1α, the master transcriptional regulator of the hypoxic response. This is mechanistically coherent: bevacizumab-induced vascular pruning creates hypoxic niches, and HIF-1α directly upregulates ANXA2 through a hypoxia-responsive element. ANXA2 can in turn stabilize HIF-1α, creating a positive feedback loop that sustains tumor progression under oxygen starvation. The team also found that ANXA2 activates STAT3 signaling, and the ANXA2-STAT3-oncostatin M receptor axis has previously been shown to drive the mesenchymal, highly invasive phenotypic changes characteristic of resistant glioblastoma.

One apparent paradox in the data deserves attention. When the researchers correlated ANXA2 expression with the cumulative number of bevacizumab cycles across the whole cohort, they found a significant negative relationship (Spearman’s r = −0.456, p = 0.009): more drug exposure was associated with lower ANXA2 expression, and patients receiving 11 to 20 cycles showed significantly reduced expression compared with those receiving 10 or fewer. The authors interpret this as a form of survivor bias. Patients who derive sustained benefit from bevacizumab continue receiving it for many cycles while maintaining low ANXA2 levels, whereas a subset of tumors with intrinsically high ANXA2 activity never respond well in the first place. In other words, the absolute ANXA2 level after drug exposure, rather than the population-wide trend, is what best reflects biological resistance and clinical outcome. Tumors that fail to suppress ANXA2 despite treatment appear predisposed to infiltrative escape and early resistance.

The study also probed whether conventional imaging could capture this biology, and the answer was largely no. Recurrence patterns on MRI—classified as contrast-enhancing T1 flare-up, T2 diffuse infiltration, or T2 circumscribed lesions—did not differ significantly in ANXA2 expression between treatment groups. Furthermore, radiological response assessed with the modified RANO 2.0 criteria, which incorporate both contrast-enhancing and FLAIR features, did not correlate significantly with survival. This dissociation between radiology and molecular pathology suggests that ANXA2-driven invasive adaptation operates below the resolution of standard imaging criteria, which are influenced by vascular density, blood-brain barrier integrity, edema, and other factors that obscure the underlying cellular behavior. A molecular biomarker may therefore detect resistance earlier and more faithfully than any scan.

The authors are candid about the limitations. The study was retrospective and not randomized, the sample size was modest, molecular profiling under the current WHO CNS5 classification—including IDH mutation status and MGMT promoter methylation—was not uniformly available, and the immunohistochemical analyses were qualitative rather than quantitatively scored. No functional validation experiments, such as ANXA2 knockdown in cell models, were performed, and the number of salvage surgical specimens was limited. The overall survival benefit of neoadjuvant bevacizumab itself requires further validation, and exploratory subgroup comparisons did not all retain statistical significance after correction for multiple comparisons. These caveats temper but do not erase the central signal, which survived multivariate adjustment and was consistent across paired, unpaired, imaging, and histological analyses.

Even so, the implications are substantial. If validated prospectively, ANXA2 could serve a dual clinical role: a predictive biomarker identifying which newly diagnosed patients will genuinely benefit from bevacizumab, and a therapeutic target whose suppression might prevent the infiltrative escape that currently undermines anti-angiogenic therapy. An ANXA2-guided strategy, in which biopsy-based expression testing directs treatment selection, would represent a meaningful step toward personalized neuro-oncology in a disease where treatment options remain desperately scarce. Recent work showing that lactylation-driven, USP4-mediated stabilization of ANXA2 maintains glioblastoma stem cells and radioresistance further suggests that drugging this pathway could attack multiple resistance mechanisms at once. For a tumor that has defeated nearly every therapeutic advance of the past two decades, a single protein that explains both prognosis and treatment failure is a lead worth chasing.

Subject of Research: Annexin A2 expression as a biomarker of bevacizumab resistance and infiltrative escape in glioblastoma

Article Title: Annexin A2 associated with bevacizumab resistance and infiltrative escape in glioblastoma

Article References: Annexin A2 associated with bevacizumab resistance and infiltrative escape in glioblastoma. (n.d.). https://doi.org/10.1007/s11060-026-05772-4

Image Credits: AI Generated

DOI: 10.1007/s11060-026-05772-4

Keywords: glioblastoma, Annexin A2, bevacizumab, drug resistance, biomarker, angiogenesis, tumor invasion, HIF-1alpha, hypoxia, neoadjuvant therapy, prognosis, neuro-oncology

The central obstacle the researchers set out to overcome is a vicious cycle linking low oxygen to drug resistance. Solid tumors, especially aggressive ones like triple-negative breast cancer, are chronically starved of oxygen because their hastily built blood vessels are irregular and dysfunctional. Oxygen can only diffuse about 100 to 200 micrometers from a functioning vessel, leaving tumor cores severely hypoxic. In this oxygen-poor environment, a transcription factor called hypoxia-inducible factor-1 alpha, or HIF-1α, becomes stabilized and switches on genes for ATP-binding cassette transporters—most notably P-glycoprotein, the efflux pump encoded by ABCB1. P-glycoprotein literally pumps chemotherapeutics like paclitaxel back out of the cell, rendering them useless. Blood transfusions and hyperbaric oxygen therapy can ease systemic hypoxia, but neither reliably relieves hypoxia inside the tumor itself.

Previous attempts to solve this problem have used hemoglobin-based oxygen carriers, since hemoglobin is the body’s natural oxygen transporter and can also catalyze the generation of reactive oxygen species. But free hemoglobin degrades rapidly, is dose-dependently toxic, and provokes systemic inflammation. Liposome-encapsulated hemoglobin improves stability, yet conventional formulations lack spatial precision, often pooling in the liver and spleen. The new study, led by Xunyi You and colleagues with senior author Ye Cao, took a different route: rather than relying on passive accumulation, the team attached their drug-loaded liposomes loosely to the surfaces of intact red blood cells—a strategy known as RBC hitchhiking.

The concept is elegantly physical. The liposomes bind to red blood cells through weak, reversible interactions such as van der Waals forces and electrostatic attraction, without being internalized. When the cell-liposome complexes are injected intravenously, they travel through the bloodstream until they squeeze through narrow capillaries. The shear forces in these tight passages mechanically scrape the nanoparticles off the red cell surfaces and transfer them to the capillary endothelium, dramatically increasing accumulation in the first capillary-rich organ downstream of the injection site. For drugs injected into a tail vein, that organ is the lung—precisely where triple-negative breast cancer metastasizes. The team’s earlier work had already shown that combining liposomes with RBC hitchhiking extends blood half-life and boosts pulmonary accumulation.

Building on that foundation, the researchers formulated liposomes from the phospholipid DPPC, the pH-sensitive lipid DOPE, and cholesterol, encapsulating both paclitaxel and purified hemoglobin in a single nanoparticle. The resulting LEHP particles measured between 100 and 200 nanometers in diameter with a polydispersity index below 0.2, indicating a highly uniform population, and transmission electron microscopy confirmed smooth, spherical structures. Paclitaxel encapsulation efficiency was 83.32 percent for hemoglobin-free liposomes and 58.27 percent for the hemoglobin-loaded version, the reduction likely reflecting the protein occupying space in the aqueous core. Critically, the hemoglobin inside LEHP showed a P50 of about 10.20 mmHg—substantially lower than the roughly 26.5 mmHg of normal adult hemoglobin—meaning a left-shifted oxygen dissociation curve and enhanced oxygen loading in the pulmonary circulation, with favorable release under the low-oxygen conditions of the tumor.

The hitchhiking step itself proved remarkably gentle on the carrier cells. After optimizing the ratio of liposomes to red blood cells, confocal microscopy showed liposomes uniformly coating the erythrocyte membranes while preserving their native biconcave disc shape. The engineered cells maintained their CD47 expression—the “don’t eat me” signal that prevents clearance by the immune system—showed no significant increase in phosphatidylserine exposure, retained normal osmotic fragility profiles, and kept their deformability index unchanged, preserving the mechanical flexibility needed to squeeze through splenic sinuses and lung capillaries.

Inside tumor cells, the payload executes a coordinated attack on two fronts. First, delivered hemoglobin alleviates hypoxia, which destabilizes HIF-1α and removes the transcriptional activation of ABCB1, sharply downregulating P-glycoprotein and restoring the cell’s vulnerability to paclitaxel. Second, the iron released from hemoglobin fuels the Fenton reaction, converting hydrogen peroxide into highly reactive hydroxyl radicals. The team documented the three hallmarks of ferroptosis—an iron-dependent form of cell death driven by lipid peroxidation: elevated labile ferrous iron, surging lipid peroxides, and a collapse of mitochondrial membrane potential. Molecular analysis showed LEHP suppressing the antioxidant guardian GPX4 and its regulator Nrf2 along with the cystine transporter SLC7A11, while upregulating the transferrin receptor, driving NCOA4-mediated ferritinophagy to liberate stored iron, and boosting ACSL4 to supply polyunsaturated fatty acid substrates for membrane oxidation. When cells were pretreated with ferrostatin-1, a specific ferroptosis inhibitor, LEHP-induced cell death was profoundly reversed—confirming ferroptosis as the dominant killing mechanism, with a minor complementary contribution from apoptosis at high drug concentrations.

The DOPE lipid added a self-amplifying delivery trick. In the acidic lysosome, DOPE destabilizes membranes and releases hemoglobin; the liberated ferrous iron then generates radicals that attack the polyunsaturated fatty acids concentrated in the lysosomal membrane itself. That peroxidation increases membrane permeability, accelerating the escape of both hemoglobin and paclitaxel into the cytosol—a ROS-dependent positive feedback loop that the team observed as early as two hours after treatment. The researchers describe the net effect as “re-oxygenation injury”: chronically hypoxic cells, adapted to survive without oxygen, are suddenly overwhelmed by an oxygen influx that their antioxidant defenses cannot absorb, triggering a catastrophic oxidative collapse.

In vivo, the advantages compounded. In mice bearing 4T1 breast cancer lung metastases, RBC-hitchhiked liposomes produced a 2.7-fold increase in pulmonary fluorescence intensity and a 4.6-fold improvement in the lung-to-liver ratio compared with liposomes alone, with lung signals persisting up to 48 hours. In the therapeutic experiment, paclitaxel monotherapy failed to arrest tumor progression, and each partial strategy—hemoglobin without hitchhiking, or hitchhiking without hemoglobin—fell short on its own. Only the fully integrated RBC-LEHP platform achieved sustained regression: at the day 13 endpoint, pulmonary bioluminescence in the RBC-LEHP group was (7.70 ± 2.86) × 10⁴, roughly three orders of magnitude below the LEP group’s (2.19 ± 0.37) × 10⁷. Histology showed intact bronchial architecture and no edema or fibrosis in treated lungs, with no systemic toxicity in the heart, liver, spleen, or kidneys, and reduced Ki67 proliferation, CD31-marked microvessel density, and MMP2 and MMP9 metastasis markers.

Perhaps most strikingly, the treatment remodeled the tumor immune microenvironment, markedly increasing infiltration of CD4-positive and CD8-positive T cells and shifting the lung tumors from an immunologically cold state toward an inflamed, hot one. High-throughput proteomics of lung tissue confirmed the mechanism at the systems level: NCOA4 upregulation and GPX4 downregulation enforcing ferroptotic commitment, HIF-1α and P-gp suppression restoring chemosensitivity, and suppression of the epigenetic driver EZH2 and the pro-survival factor CEBPB dismantling the tumor’s transcriptional survival programs. The authors caution that some hepatic accumulation was observed at 24 hours, though without histological signs of liver damage, and that systemic immune responses in peripheral lymphoid organs remain to be profiled. Still, the study establishes a compelling template—targeted delivery, hypoxia alleviation, ferroptosis plus chemotherapy, tumor suppression—that could extend beyond breast cancer to any malignancy whose resistance is rooted in the oxygen-starved depths of the tumor.

Subject of Research: A biomimetic erythrocyte-hitchhiking liposome system delivering hemoglobin and paclitaxel to overcome hypoxia-driven chemoresistance in triple-negative breast cancer lung metastasis via ferroptosis

Article Title: Oxygen-augmented erythrocyte-liposome hybrids to overcome paclitaxel resistance in triple-negative breast cancer metastasis via enhanced ferroptosis

Article References: You, X., Zhu, K., Li, W., Wang, H., Zhong, R., Li, S., Liu, J., Wong, Y. S., Venkatraman, S. S., & Cao, Y. (2026). Oxygen-augmented erythrocyte-liposome hybrids to overcome paclitaxel resistance in triple-negative breast cancer metastasis via enhanced ferroptosis. Materials Today Bio, 41, Article 103705. https://doi.org/10.1016/j.mtbio.2026.103705

Image Credits: AI Generated

DOI: 10.1016/j.mtbio.2026.103705

Keywords: triple-negative breast cancer, ferroptosis, red blood cell hitchhiking, liposomes, tumor hypoxia, HIF-1alpha, P-glycoprotein, paclitaxel, drug resistance, lung metastasis, hemoglobin, nanomedicine

The research, led by Liang-rui Qin and Can Hu of the State Key Laboratory of Ultrasound in Medicine and Engineering at Chongqing Medical University, together with colleagues including corresponding authors Yong-hong Du and Dai-rong Li, focused on a deceptively straightforward therapeutic idea: deliver oxygen-generating capacity directly into the granuloma microenvironment. Catalase is an enzyme that breaks down hydrogen peroxide into water and molecular oxygen. By injecting catalase locally into tuberculous granulomas at defined stages of infection, the team hoped to relieve the hypoxia, the severe oxygen depletion, that characterizes these lesions and that has long been suspected of undermining both immune function and drug efficacy.

To test the concept, the researchers established a murine subcutaneous tuberculous granuloma model using Bacillus Calmette-Guérin, or BCG, the attenuated mycobacterial strain best known as the tuberculosis vaccine. Mice were divided into treatment groups receiving either catalase, cobalt chloride, a chemical that mimics hypoxia, or a saline control. Crucially, the interventions were timed: one group received treatment at day six after infection, representing an early stage of granuloma formation, while another received it at day twelve, when lesions were more established. The team then assessed outcomes using a battery of techniques including histopathology, immunohistochemistry, immunofluorescence, enzyme-linked immunosorbent assays, and lipidomics, an analytical approach that profiles the full repertoire of lipid species in tissue.

The baseline findings were sobering. As BCG infection progressed, the granulomas became progressively more hypoxic, and this deterioration was accompanied by vascular dysfunction, visible as reduced expression of CD31, a marker of endothelial cells, and alpha-smooth muscle actin, a marker of vascular mural cells. Collagen deposition increased, scarring the lesions and further restricting blood flow. Lipid accumulated within the tissue, and bacterial load, measured as colony-forming units, climbed in parallel. In other words, the granuloma behaves like a self-reinforcing vicious cycle: poor vasculature starves the tissue of oxygen, hypoxia damages vessels further and promotes fibrosis and fat buildup, and the worsening microenvironment favors bacterial persistence.

Against this backdrop, the results of early catalase intervention stood out sharply. When catalase was administered at day six, the treatment downregulated hypoxia inducible factor-1 alpha, the master molecular switch that cells activate under low oxygen, along with vascular endothelial growth factor, a signaling protein that hypoxic tissues produce to stimulate new but often dysfunctional blood vessel growth. With the hypoxic burden lifted, the vascular structure inside the granulomas improved, as did vessel permeability, potentially opening a window for drugs that would otherwise fail to reach the bacteria. Collagen and lipid deposition both declined, indicating that the fibrotic and metabolic deterioration of the lesion had been blunted.

Perhaps the most technically intriguing finding came from the lipidomics analysis. Early catalase treatment did not simply reduce lipid accumulation indiscriminately; it specifically reshaped the lipid profile of the granuloma. The phospholipid species phosphatidylserine 18:0/18:0 was downregulated, while multiple subtypes of phosphatidylinositol and phosphatidylethanolamine were upregulated. This specificity matters because mycobacteria are notorious lipid manipulators: they co-opt host lipid metabolism to build their own protective niches inside macrophages, and aberrant lipid handling within granulomas has been linked to bacterial persistence and lesion necrosis. The finding suggests that oxygen restoration does not merely improve tissue plumbing but actively recalibrates the metabolic landscape on which the bacteria depend.

Timing, however, proved to be everything. When catalase was given at day twelve, well after the granulomas had matured, the therapeutic benefit was markedly limited. The late-stage lesions, already entrenched in hypoxia, fibrosis, and lipid dysregulation, apparently could not be rescued by a single round of oxygen-generating enzyme therapy. Conversely, when the researchers injected cobalt chloride to chemically induce hypoxia, every pathological measure worsened: vascular markers fell further, collagen and lipid deposition increased, and the lesions deteriorated across the board. This reciprocal experiment strengthens the causal argument that hypoxia is not merely correlated with granuloma progression but actively drives it.

The implications for tuberculosis therapy are potentially significant. Current drug regimens for tuberculosis require months of multidrug therapy, and treatment failure is often attributed to poor drug penetration and the metabolically dormant state that bacteria adopt in hypoxic lesions. If restoring oxygenation can normalize granuloma vasculature and reverse the metabolic conditions that shelter persistent bacteria, catalase-based local oxygen therapy could, in principle, serve as an adjunct that makes existing antibiotics work better, rather than a replacement for them. The study’s authors note that their findings suggest a potential application prospect in animal models that more closely recapitulate human tuberculosis, an important caveat, since the subcutaneous BCG model, while tractable and ethically manageable, differs in key respects from pulmonary infection with virulent M. tuberculosis in humans.

Those caveats deserve emphasis. BCG is an attenuated organism, and the granulomas in this model form in the skin rather than the lung, where the architecture of human tuberculous lesions, including caseous necrosis and cavitation, presents additional barriers. The dosing, delivery route, and safety profile of local catalase administration would all need to be established in more faithful models before any translation toward patients could be contemplated. Nonetheless, the study offers a mechanistically grounded proof of concept that the pathological microenvironment of a granuloma is a druggable target in its own right, and that the window for intervening is early, before fibrosis and lipid derangement become irreversible.

What makes the work resonate beyond tuberculosis is its broader message about infectious disease: the battlefield matters as much as the combatants. Rather than attacking the bacteria directly, this approach remodels the tissue ecosystem in which the bacteria survive, targeting hypoxia signaling, vascular integrity, and lipid metabolism simultaneously. As researchers increasingly recognize that chronic infections are sustained by microenvironmental niches, strategies that restore normal tissue physiology, whether through oxygen-generating enzymes, vascular repair, or metabolic modulation, may complement the antibiotic arsenal in ways that new drugs alone cannot. For a disease that still kills well over a million people each year, even a modest improvement in drug penetration and bacterial clearance inside granulomas could translate into shorter cures and fewer treatment failures. The Chongqing team’s catalase experiments are an early step, but they point toward a reframing of tuberculosis therapy: treat the lesion, not just the microbe.

Subject of Research: Catalase-based local oxygen therapy targeting hypoxia and lipid metabolism in tuberculous granulomas

Article Title: Therapeutic effects of early catalase intervention in tuberculous granulomas: targeting hypoxia and lipid dysregulation

Article References: Therapeutic effects of early catalase intervention in tuberculous granulomas: targeting hypoxia and lipid dysregulation. (n.d.). https://doi.org/10.1186/s12879-026-14516-8

Image Credits: AI Generated

DOI: 10.1186/s12879-026-14516-8

Keywords: tuberculosis, granuloma, catalase, hypoxia, HIF-1alpha, oxygen therapy, BCG, lipidomics, vascular dysfunction, fibrosis, mouse model, BMC Infectious Diseases

Microglia are the sentinels of the central nervous system. In the healthy brain they patrol their territory with ramified processes, sampling the microenvironment for signs of danger. When ischemia strikes, they rapidly shift into an activated state, and for years researchers described this shift using a binary model: pro-inflammatory M1-like microglia that amplify tissue damage, and anti-inflammatory M2-like microglia that promote repair. The new review argues that this tidy dichotomy has outlived its usefulness. Single-cell sequencing studies have revealed a far richer spectrum of microglial subtypes, each with distinct transcriptional profiles, metabolic preferences, and functional consequences. Polarization, in this view, is not a switch but a continuum—a dynamic landscape of states that cells occupy, abandon, and re-enter as the post-stroke environment evolves.

At the heart of this transformation lies a profound metabolic reprogramming. Resting microglia rely primarily on oxidative phosphorylation, the efficient mitochondrial process that converts nutrients into ATP. After ischemia, however, oxygen and glucose scarcity forces a shift toward aerobic glycolysis, the same fermentative strategy that Warburg observed in cancer cells. This metabolic pivot is orchestrated in large part by hypoxia-inducible factor 1-alpha, or HIF-1α, which stabilizes under low-oxygen conditions and drives expression of glycolytic enzymes such as hexokinase 2. The result is a cell that burns glucose wastefully but rapidly, generating the biosynthetic intermediates and NADPH it needs to fuel an immune response—while simultaneously producing lactate and succinate as metabolic byproducts with signaling roles of their own.

The review pays particular attention to mitochondria, which are not merely passive casualties of ischemia but active participants in the inflammatory cascade. Under normal conditions, a network of mitochondrial quality control mechanisms—collectively termed MQC—keeps these organelles healthy. Mitochondrial dynamics, the constant fission and fusion of the network, allow damaged segments to be segregated. Mitophagy, guided by the PINK1-Parkin pathway, then removes severely compromised mitochondria before they can do harm. Ischemia disrupts this surveillance system. The mitochondrial permeability transition pore opens, membrane potential collapses, and the quality control machinery becomes overwhelmed. The consequence is the release of a battery of mitochondrial damage-associated molecular patterns: reactive oxygen species generated at the electron transport chain, fragments of oxidized mitochondrial DNA, and cardiolipin, a phospholipid normally confined to the inner mitochondrial membrane that becomes a potent danger signal when exposed to the cytosol.

These mitochondrial alarm signals converge on one of the most consequential immune complexes known: the NLRP3 inflammasome. NLRP3, a cytosolic pattern-recognition receptor, assembles with the adaptor protein ASC and procaspase-1 into a multi-protein platform that activates caspase-1. The review highlights how several metabolic and mitochondrial cues converge to trigger this assembly. Succinate, which accumulates during ischemia, can drive reverse electron transport through mitochondrial complex I, supercharging the production of mitochondrial reactive oxygen species. Oxidized mitochondrial DNA binds directly to NLRP3. Extracellular lactate and cytosolic cardiolipin provide additional priming and activation signals. Once assembled, the inflammasome executes its inflammatory program: caspase-1 cleaves pro-interleukin-1β and pro-interleukin-18 into their mature, secreted forms, and cleaves gasdermin D to release its N-terminal fragment, GSDMD-NT.

What happens next is where the review makes its most striking conceptual contribution. GSDMD-NT is not simply a bystander in inflammation—it migrates to the mitochondria and perforates both the inner and outer mitochondrial membranes, forming pores that further destabilize these organelles. This establishes a self-amplifying positive feedback loop: mitochondrial damage releases the signals that activate the NLRP3 inflammasome, and inflammasome activation inflicts further mitochondrial damage. In the ischemic brain, where microglia are already metabolically stressed, this loop can lock the cell into a hyperinflammatory state that persists long after the initial insult. The authors also note that activated mitochondrial DNA can engage the STING pathway, adding an interferon-mediated dimension to the inflammatory response and further entrenching the pro-inflammatory phenotype.

Crucially, the review insists that this axis cannot be understood without considering time. The authors stratify the MQC–metabolism–inflammation network into three temporal phases. In the hyperacute phase, within minutes to hours of vessel occlusion, energy failure and mitochondrial permeability transition dominate, and the earliest danger signals are released. In the subacute phase, spanning hours to days, microglial polarization reaches its peak, glycolytic reprogramming is fully established, and NLRP3-driven cytokine release shapes the evolving lesion. In the chronic phase, weeks to months later, a lingering population of chronically activated microglia sustains low-grade inflammation that interferes with tissue remodeling and repair. Each phase, the authors argue, presents distinct therapeutic windows and distinct molecular targets, and interventions that ignore this temporal structure are unlikely to succeed.

The review is also refreshingly candid about the translational bottlenecks that have stalled progress from bench to bedside. Numerous NLRP3 inhibitors and mitochondrial protective agents have shown promise in rodent models of stroke, yet clinical trials have repeatedly disappointed. One reason, the authors emphasize, lies in fundamental differences between mice and humans. The NLRP3 inflammasome and its regulatory feedback mechanisms differ in important ways between the two species, meaning that regulatory circuits mapped in mouse models must be interpreted with caution before being extrapolated to patients. The authors call for humanized models and bidirectional clinical validation to close this gap, alongside single-cell multi-omics approaches to map the full diversity of microglial subpopulations in the human ischemic brain, and metabolic flux analysis to quantify the actual thresholds at which metabolites such as succinate and lactate become pathogenic.

Two testable hypotheses emerge from the framework. The first proposes that the strength and duration of the mitochondrial damage–inflammasome feedback loop determines whether microglia resolve toward a reparative phenotype or remain trapped in a chronic inflammatory state—suggesting that early stabilization of mitochondrial quality control could steer the entire trajectory of post-stroke inflammation. The second proposes that specific metabolite thresholds, rather than bulk shifts in metabolic pathway activity, are the critical determinants of NLRP3 activation, implying that precise quantification of metabolite flux in individual microglial subtypes will be essential for rational drug design. Both hypotheses lend themselves to direct experimental interrogation with the tools now available, from metabolomics to live imaging of mitochondrial dynamics.

For a field that has long treated metabolism, mitochondria, and inflammation as separate chapters of the stroke story, this integrated framework offers something genuinely new: a systems-level map of how the pieces fit together in space and time. If the hypotheses hold up, the implications extend beyond ischemic stroke to any neurological condition in which microglial metabolism and inflammasome activation run amok, from traumatic brain injury to neurodegenerative disease. The therapeutic challenge remains formidable—timing interventions to the right phase, achieving selectivity for pathogenic microglial states, and bridging the species divide—but the review provides a clear conceptual scaffold on which the next generation of experiments, and perhaps eventually therapies, can be built.

Subject of Research: Microglial metabolic reprogramming, mitochondrial dysfunction, and NLRP3 inflammasome activation in cerebral ischemia

Article Title: Metabolic reprogramming and polarization of microglia in cerebral ischemia: the roles of mitochondria and inflammasomes

Article References: Ding, Y., Li, N., Li, Q., Zhang, H., He, L., Gao, F., & Li, P. (2026). Metabolic reprogramming and polarization of microglia in cerebral ischemia: the roles of mitochondria and inflammasomes. Journal of Translational Medicine. https://doi.org/10.1186/s12967-026-08947-9

Image Credits: AI Generated

DOI: 10.1186/s12967-026-08947-9

Keywords: ischemic stroke, microglia, mitochondrial quality control, metabolic reprogramming, NLRP3 inflammasome, neuroinflammation, mitochondrial dysfunction, aerobic glycolysis, gasdermin D, single-cell sequencing, HIF-1alpha, neuroimmunology

The framework rests on a simple but powerful physiological observation. Every step of the oxygen cascade shows measurable age-related decline. Starting at roughly 21 percent of inspired oxygen at sea level, the partial pressure of oxygen drops sequentially across the alveoli, the arterial blood, the microcirculation, the interstitial space, and the mitochondria. In youth, this cascade is buffered by remarkable resilience: ventilation, cardiac output, capillary recruitment, and mitochondrial function adjust continuously to match oxygen supply with metabolic demand. With age, that adaptive capacity erodes at every level simultaneously. The authors emphasize that Oxygenaging is not simply a state of oxygen deficiency. Rather, it reflects a progressive loss of resilience in the mechanisms that maintain oxygen homeostasis, leaving older organisms increasingly vulnerable to mismatches between oxygen availability and energetic requirements — mismatches that compromise cellular function, tissue integrity, and physiological reserve.

The first step of the cascade, pulmonary gas exchange, deteriorates through well-characterized structural changes. Age-related loss of elastin fibers reduces lung elastic recoil, promoting premature closure of small airways, particularly in gravity-dependent regions of the lung. These poorly ventilated but still perfused units act as functional shunts, widening the alveolar-arterial oxygen gradient and increasing ventilation-perfusion heterogeneity — quantified by the log standard deviation of perfusion distribution, which rises from roughly 0.36 in younger adults to 0.47 in older individuals. Empirical reference equations established decades ago show that age is the single most robust predictor of arterial oxygenation, with arterial oxygen partial pressure falling by approximately 15 to 20 mmHg between mid-life and old age. The review also highlights a less appreciated mechanism: systemic iron deficiency, common in aging, mimics hypoxia at the pulmonary endothelium by inhibiting prolyl hydroxylase domain enzymes, exaggerating hypoxic pulmonary vasoconstriction and placing additional strain on the right ventricle.

The second step, central hemodynamics, compounds the problem. Oxygen delivery is the product of arterial oxygen content and cardiac output, and in aging the decline in maximal heart rate — dropping roughly 25 percent, from about 200 beats per minute in youth to about 150 in old age — becomes the dominant bottleneck on peak oxygen delivery. The aging system also fails to shift the hemoglobin-oxygen dissociation curve rightward at baseline to facilitate tissue oxygen unloading; because systemic 2,3-bisphosphoglycerate levels do not rise with healthy aging, tissues depend heavily on acute stressors such as the heat and acidosis of exercise — the Bohr effect — to release oxygen from hemoglobin. Combined with the flat upper plateau of the dissociation curve, which prevents healthy lung regions from over-compensating for failing ones, these deficits translate into a measurable drop in overall arterial saturation and a progressive constraint on systemic oxygen supply.

The third and arguably most consequential step occurs in the microvasculature. Maximal oxygen uptake, the integrated measure of the entire cascade, falls by approximately 10 percent per decade, limited both by reduced central delivery and by peripheral failure of oxygen extraction. Aging brings microvascular rarefaction, endothelial dysfunction with reduced nitric oxide bioavailability, and increased diffusion distances caused by fibrosis and diminished pericyte coverage. Even when bulk blood flow appears adequate, the aged microvasculature mounts a sluggish hyperemic response to exertion, failing to raise microvascular oxygen pressure precisely when the diffusion gradient into mitochondria is needed most. Notably, the authors point to a metabolic peculiarity of endothelial cells: they rely primarily on glycolysis rather than oxidative phosphorylation, and aging disrupts this specialization, crippling the migratory and proliferative machinery required for angiogenesis. This explains why simply supplementing oxygen may fail to rescue microvascular function in older tissues.

Organ-specific evidence grounds the framework in measurable clinical data. Near-infrared spectroscopy studies show regional cerebral oxygen saturation falling from roughly 69.8 percent in young adults to 62.7 percent in older adults, driven by pericyte degeneration, blood-brain barrier leakage, and uncoupling of endothelial nitric oxide synthase within the neurovascular unit. Renal BOLD-MRI reveals progressive medullary hypoxia as peritubular capillary rarefaction and tubulointerstitial fibrosis enlarge diffusion distances. In skin, transcutaneous oxygen measurements expose a blunted neurogenic vasodilatory response to thermal stress, reflecting extracellular matrix stiffness that mechanically limits vessel expansion. In skeletal muscle, phosphorus-31 magnetic resonance spectroscopy shows that post-exercise phosphocreatine recovery slows from about 37 seconds in young muscle to about 52 seconds in aged muscle, paralleled by reduced mitochondrial content, mild uncoupling via uncoupling protein 3, and instability of respiratory supercomplexes.

At the molecular level, the review describes how the hypoxia-inducible factor system — the ancient oxygen-sensing machinery conserved across metazoans — becomes maladaptive with age. In youth, prolyl hydroxylase domain enzymes use oxygen, alpha-ketoglutarate, and iron to tag HIF-1alpha for degradation, keeping the pathway exquisitely responsive to genuine hypoxia. With aging, declining NAD+ reduces SIRT1 activity and lowers von Hippel-Lindau expression, while accumulating succinate directly inhibits PHD catalytic activity. Both routes converge on the same outcome: stabilization of HIF-1alpha under normal oxygen conditions, a state the authors term chronic pseudohypoxia. This maladaptive activation suppresses mitochondrial biogenesis through the MYC-TFAM axis, impairs mitophagy through lysosomal dysfunction, and leaves a pool of damaged, reactive-oxygen-species-leaking mitochondria. The framework also intersects with iron biology — what the authors call Ferroaging — as an expanded labile iron pool catalyzes the Fenton reaction during reoxygenation, priming vulnerable cells for ferroptosis, an iron-dependent form of cell death.

The consequences ripple through metabolism and the genome. Hyperactive mTOR signaling in aging overrides HIF-1alpha’s normal metabolic brake, forcing cells to continue energy-consuming anabolic growth despite insufficient oxygen. HIF-1alpha-mediated suppression of lipolysis — the so-called lipid lock — promotes triglyceride accumulation and hepatic steatosis. Meanwhile, oxygen availability physically constrains the dioxygenase enzymes that govern the epigenetic clock: ten-eleven translocation enzymes and JmjC-domain histone demethylases all require oxygen as a co-substrate, so declining tissue oxygen pressure may directly accelerate the accumulation of aberrant methylation patterns characteristic of cellular senescence. Supporting this, the authors’ own recent work showed that intermittent hypoxia in old mice accelerated epigenetic age in lung, spleen, and heart by up to five months — an effect that reversed after return to normoxia. Hypoxia also reshapes the RNA splicing landscape, promoting intron retention and isoform switching that, when dysregulated by age-related transcriptomic noise, may generate aberrant proteins and neoepitopes that provoke immune surveillance.

The framework’s most provocative implications are therapeutic. The authors survey emerging gerotherapies that deliberately modulate the oxygen cascade: intermittent hypoxia, which in carefully dosed protocols activates neurotrophic BDNF-TrkB signaling and enhances motor recovery after spinal cord injury; hyperbaric oxygen therapy, which exploits the hyperoxic-hypoxic paradox — the rapid pressure drop from over two atmospheres back to sea level — to trigger HIF-1alpha signaling without true hypoxia, with preliminary reports of telomere elongation exceeding 20 percent in immune cells and clearance of senescent T cells; and intermittent hypoxic-hyperoxic training, which alternates low and high oxygen to drive mitophagy-based mitochondrial selection. The authors caution, however, that the hormetic dose-response curve likely shifts with age: interventions beneficial in young organisms may prove toxic in frail older adults whose NRF2-mediated antioxidant buffering is compromised. Sex differences, frailty, and individual variability in hypoxic ventilatory response further narrow the therapeutic window. Their prescription for the field is rigorous: define therapeutic windows tailored to biological rather than chronological age, monitor real-time biomarkers of oxidative stress and mitochondrial function during therapy, and conduct randomized controlled trials stratified by frailty status. Oxygen-sensing pathways, they argue, represent a high-leverage gerotherapeutic target — one that could help decouple chronological age from biological decay and chart a roadmap toward extending human healthspan.

Subject of Research: Age-related decline in the oxygen transport cascade and its role in the biology of aging

Article Title: Oxygenaging: A Physiological Framework for Geroscience

Article References: Donega, S., Fishbein, K. W., Dominelli, P., Herman, A. B., de Cabo, R., Gorospe, M., & Ferrucci, L. (2026). Oxygenaging: A Physiological Framework for Geroscience. Aging Cell, 25(9), Article e70664. https://doi.org/10.1111/acel.70664

Image Credits: AI Generated

DOI: 10.1111/acel.70664

Keywords: Oxygenaging, geroscience, oxygen cascade, HIF-1alpha, mitochondrial dysfunction, microvascular rarefaction, pseudohypoxia, ferroptosis, hyperbaric oxygen therapy, intermittent hypoxia, epigenetic aging, Aging Cell

The research, led by scientists at the Stazione Zoologica Anton Dohrn in Naples, Italy, set out to address a glaring gap in comparative physiology. Intertidal bivalves are famous for their tolerance of hypoxia and reoxygenation, but the cellular and molecular mechanisms behind that tolerance remain largely unexplored, particularly in the nervous system. This is a critical blind spot, because neural tissue is among the most metabolically active in any animal, demanding a continuous supply of oxygen to sustain ion gradients, neurotransmitter cycling, and the electrical signaling that underpins behavior. In humans, even brief interruptions of cerebral oxygen flow cause devastating damage, which makes the mussel’s nonchalance all the more intriguing.

To build a foundation, the team first performed a detailed histochemical characterization of each ganglion of the mussel’s nervous system, mapping out the architecture of the cerebro-pleural ganglia, pedal ganglia, and visceral ganglia, along with the commissures and connectives that link them. Using molecular markers, they charted the distribution of catecholaminergic, peptidergic, and serotonergic neurons, identifying populations of cells that produce dopamine-like catecholamines, the neuropeptide FMRFamide, and serotonin. This anatomical atlas provided the necessary roadmap for asking which parts of the mussel brain respond when oxygen disappears and returns.

The pedunculate pedal ganglia emerged as a focal point of the response. Histochemical analysis showed that catecholaminergic, peptidergic, and serotonergic neurons distributed within the pedal ganglia contribute to the homeostatic response to hypoxia and the subsequent reoxygenation phase. In practical terms, this means that the mussel’s nervous system does not simply shut down and ride out the stress passively; instead, specific neurochemical signaling systems modulate their activity in a coordinated way as conditions change. Neuroplasticity of this kind, the authors conclude, represents one important component of a broader, integrated set of strategies that the animal deploys to adapt to fluctuating oxygen.

But neurochemical remodeling is only part of the story. To probe deeper, the researchers turned to transcriptomics, sequencing the messenger RNA landscape of the pedal ganglia under normoxic, hypoxic, and reoxygenation conditions. This unbiased approach generated a catalog of candidate adaptive genes whose expression shifts in response to oxygen stress, spanning multiple biological processes. Among the most prominent functional categories were the regulation of cellular homeostasis, the control of programmed cell death, the regulation of cell proliferation, and, perhaps unsurprisingly, mitochondrial biology. Mitochondria are the cellular power plants where oxygen is consumed, and they are also the primary source of the reactive oxygen species that spike dangerously when oxygen suddenly returns after a period of scarcity.

Several of the genes flagged by the analysis belong to pathways that will be familiar to anyone who studies hypoxia biology. The hypoxia-inducible factor pathway, centered on the transcription factor HIF-1α and its regulators, including prolyl hydroxylase domain-containing protein 2 and the von Hippel–Lindau tumor suppressor, is the canonical oxygen-sensing machinery of animal cells. The transcriptomic data also pointed to genes involved in antioxidant defense, mitochondrial electron transport, and even an alternative oxidase, a mitochondrial enzyme that allows some invertebrates to keep electrons flowing through their respiratory chains in ways that sidestep the reactive oxygen bursts typical of standard respiration. Genes connected to apoptosis regulation, including components of tumor necrosis factor receptor signaling, suggest that the mussel brain actively manages the decision between cell survival and cell death during stress.

Markers of cell proliferation, such as proliferating cell nuclear antigen, added another dimension. Their presence hints that the mussel nervous system may maintain or even replenish its cellular components in response to stress, a form of structural plasticity that complements the neurochemical changes. Taken together, the transcriptomic results paint a picture of a nervous system that engages a coordinated transcriptional program, adjusting everything from energy metabolism to life-and-death decisions at the single-cell level, in order to preserve function through cycles of oxygen withdrawal and restoration.

The team then asked whether microRNAs, the small regulatory RNAs that fine-tune gene expression after transcription, might orchestrate these responses. MicroRNAs are powerful post-transcriptional regulators in virtually every animal lineage, and they have been implicated in hypoxic responses in mammals. Using small RNA sequencing, the researchers identified a suite of mature microRNAs expressed in the pedal ganglia, including microRNAs that appear to be entirely novel to science. However, when they compared the miRNA profiles across hypoxia and reoxygenation conditions, they found no significant changes. This negative result is itself informative: it suggests that post-transcriptional regulation mediated by microRNAs plays, at most, a secondary role in how the mussel nervous system copes with fluctuating oxygen, leaving transcriptional regulation and neurochemical plasticity as the primary levers of adaptation.

The study represents the first comprehensive look at the molecular and cellular regulatory mechanisms that allow the nervous system of M. galloprovincialis to adapt to natural oxygen fluctuations. Its significance extends well beyond molluscan curiosity. As climate change warms the oceans and coastal waters experience increasingly frequent and severe hypoxic events, understanding how resilient species maintain neural function under oxygen stress becomes a matter of ecological urgency. Mussels are ecosystem engineers, forming reefs that shelter entire communities, and their capacity to withstand deoxygenation shapes the fate of these habitats. Moreover, the conserved pathways uncovered in this work, from HIF signaling to mitochondrial alternative oxidases, offer comparative insights that may one day illuminate how mammalian brains, including our own, could be better protected against ischemia and reperfusion injury.

There is also a humbling evolutionary lesson embedded in the data. The molecular tools the mussel deploys, including oxygen sensors, mitochondrial safeguards, apoptotic gatekeepers, and modulatory neurotransmitters, are not exotic inventions. They are variations on themes shared across the animal kingdom, tuned by natural selection in an environment where oxygen comes and goes with the tides. What the Naples team has shown is that resilience is not a single trait but an orchestra: neurochemical flexibility in defined ganglia, a shifting transcriptomic program governing homeostasis, death, proliferation, and mitochondria, and a microRNA layer that, in this context, appears to hold steady while the rest of the system adapts. As hypoxic waters spread across the world’s coastlines, the lowly Mediterranean mussel may prove to be one of the best teachers we have about how nervous systems endure the thin line between suffocation and recovery.

Subject of Research: Neural and molecular adaptations of the Mediterranean mussel Mytilus galloprovincialis to hypoxia and reoxygenation stress.

Article Title: Effect of hypoxia and reoxygenation on the nervous system of the Mediterranean mussel Mytilus galloprovincialis

Article References: van Gelderen, T. A., D’Aniello, E., Macina, A., D’Aniello, S., Gallo, A., Carrella, S., & Mirra, S. (2026). Effect of hypoxia and reoxygenation on the nervous system of the Mediterranean mussel Mytilus galloprovincialis. BMC Biology. https://doi.org/10.1186/s12915-026-02731-3

Image Credits: AI Generated

DOI: 10.1186/s12915-026-02731-3

Keywords: hypoxia, reoxygenation, Mytilus galloprovincialis, nervous system, neuroplasticity, pedal ganglia, transcriptomics, microRNAs, mitochondria, HIF-1alpha, intertidal bivalves, marine biology