Researchers treated U937 macrophage cells with 250 micromolar dimethyl itaconate, or DMI, for 48 hours. They then isolated exosomes from the treated cultures, characterized the vesicles and applied them to MCF-7 cells. Western blotting was used to measure proteins associated with epithelial–mesenchymal transition, including E-cadherin, N-cadherin, ZEB1/2, Slug, and Vimentin. Exposure to the DMI-derived exosomes, designated DMI-EXO, significantly increased N-cadherin, ZEB1/2, Slug, and Vimentin while reducing E-cadherin. Together, these protein changes were consistent with a shift in the cancer cells toward a more mesenchymal state.

The investigators also examined microRNAs associated with EMT regulation. Quantitative real-time PCR showed that DMI-EXO significantly reduced miR200C-5p and miR30C-5p, two of the EMT-suppressive microRNAs assessed in the study. No significant change was detected in miR-137 expression. The results connect altered microRNA abundance with the protein changes associated with EMT, although the experiments do not establish that either microRNA was the direct mechanism responsible for migration or invasion. The study also evaluated miR-638, but the supplied results do not report a specific change in that microRNA.

Functional assays showed that the DMI-EXO treatment affected the movement of MCF-7 cells. In the scratch wound-healing assay, treated cells closed the artificial gap faster than comparison cells. In a Transwell invasion assay, the DMI-EXO group developed a larger invaded area. These measurements support enhanced migration and invasion, respectively. By contrast, Annexin V/propidium iodide staining showed no significant alteration in apoptosis after DMI-EXO exposure. The findings therefore point to changes in motility and invasion rather than a detectable change in cancer-cell death as the principal response under the experimental conditions.

This work provides evidence that macrophage-derived extracellular vesicles can transmit a tumor-associated influence between immune cells and breast cancer cells. Itaconic acid is an immunometabolite involved in macrophage polarization within the tumor microenvironment, but its effects on cancer progression have remained debated. The present results suggest one possible route: DMI treatment alters what macrophages release in exosomes, and those vesicles then promote EMT-associated protein and microRNA patterns together with greater migration and invasion in recipient MCF-7 cells. The findings are nevertheless limited to an in vitro cell-culture model, one macrophage cell line, one breast cancer cell line, and specified treatment conditions. They do not show that dimethyl itaconate produces the same effects in intact animals or people, and they do not demonstrate improved outcomes for patients with breast cancer.

Subject of Research: Effects of dimethyl-itaconate-treated macrophage exosomes on EMT, migration, invasion, and apoptosis in MCF-7 breast cancer cells

Article Title: Exosomes derived from itaconate-treated macrophages promote epithelial–mesenchymal transition, migration, and invasion in MCF-7 breast cancer cells

Article References: Siahi, F. H., Yektaseresht, A., & Tabandeh, M. R. (2026). Exosomes derived from itaconate-treated macrophages promote epithelial–mesenchymal transition, migration, and invasion in MCF-7 breast cancer cells. Medical Oncology, 43(11), Article 348. https://doi.org/10.1007/s12032-026-03468-3

Image Credits: AI Generated

DOI: 10.1007/s12032-026-03468-3

Keywords: breast cancer cells, macrophage exosomes, dimethyl itaconate, epithelial–mesenchymal transition, cell migration, cell invasion, microRNAs, tumor microenvironment, in vitro research, Exosomes, derived, itaconate-treated

The study addressed an apparent contradiction in the biology of p75NTR, a member of the tumor necrosis factor receptor superfamily that regulates cell death, survival and differentiation in a context-dependent manner. Earlier experiments had associated the receptor with enhanced osteogenesis in some mesenchymal cell systems, while other studies reported inhibitory effects. The researchers examined p75NTR-knockout mice and ectomesenchymal stem cells, or EMSCs, isolated from the maxillofacial tissue of E16.5 embryos.

Knockout animals were smaller than their wild-type littermates and showed delayed skeletal development, with more cartilage and less mineralized bone. Micro-computed tomography also revealed reduced bone volume fraction, bone mineral density and trabecular number in the femur and mandible. The knockout phenotype was not confined to a single differentiation assay.

Flow cytometry showed that wild-type and knockout EMSCs expressed the mesenchymal stem-cell markers CD29, CD90 and Sca-1 at high frequencies while showing little expression of the hematopoietic marker CD45, supporting their characterization as mesenchymal stem-cell-like populations. However, knockout EMSCs displayed weaker multilineage differentiation than wild-type cells. After osteogenic induction, knockout cultures formed fewer calcium deposits, while adipogenic and chondrogenic assays showed fewer lipid droplets and cartilage nodules.

These observations placed the therapeutic work in the context of a broad developmental impairment associated with the loss of p75NTR. The researchers isolated extracellular vesicles by differential ultracentrifugation from cultures of wild-type and knockout EMSCs. Wild-type vesicles had a mean particle diameter of 142.6 ± 64.9 nanometres, and knockout-derived vesicles measured 150.5 ± 95.8 nanometres.

Transmission electron microscopy showed rounded or cup-shaped structures in both preparations. Both vesicle types contained the exosomal markers TSG101 and CD9 but lacked detectable calnexin, an endoplasmic-reticulum marker used as a negative control. Fluorescently labelled wild-type vesicles entered recipient EMSCs and accumulated in the perinuclear region at 12 and 24 hours.

In cell-culture assays, wild-type vesicles increased knockout-cell viability in a concentration-dependent manner; 50 micrograms per millilitre produced a 24% increase in viability over the control group on day five. At that dose, proliferation of treated knockout cells approached the wild-type level by day five, although the authors described the effect as a partial restoration of proliferative capacity. Alkaline phosphatase staining indicated stronger early differentiation, while Alizarin Red staining after 21 days showed more calcium-nodule formation.

At 50 micrograms per millilitre, the treated knockout cells expressed several osteogenic markers at levels similar to those of untreated wild-type cells. Conversely, vesicles derived from knockout EMSCs suppressed collagen I, alkaline phosphatase and Runx2 expression in wild-type cells. The reciprocal pattern shows that vesicle activity differed according to the donor cells’ p75NTR state, but the experiments did not identify which exosomal cargo was responsible.

To improve local retention and duration of treatment, the team encapsulated wild-type vesicles in the aqueous core of coaxial electrospun fibres. The shell combined silk fibroin and polycaprolactone, while the core contained polyvinyl alcohol and the vesicles. After screening several shell compositions and loading concentrations, the authors selected an SF/PCL ratio of 2:5 and a vesicle concentration of 10 milligrams per millilitre.

Scanning electron microscopy showed relatively uniform fibres in the selected formulation, with a mean diameter of 146.8 ± 27.6 nanometres before vesicle loading and 156.9 ± 40.5 nanometres afterward. Dual fluorescence confirmed that the vesicle-containing solution occupied the core of the fibres. Release followed a three-stage pattern, with an initial burst followed by more gradual delivery over 28 days.

By day 28, cumulative release reached 56.88 ± 2.01% for the selected formulation, and released vesicles were taken up by knockout EMSCs during culture. The membrane was biocompatible with knockout EMSCs: live/dead staining detected no dead cells after three days, and the exosome-loaded membrane accelerated proliferation from day three through day five. At seven and 14 days, alkaline-phosphatase activity was higher with the loaded membrane than with the unloaded membrane or control, while the loaded membrane group showed the highest observed activity.

At 21 days, the loaded membrane produced the greatest mineral deposition, and immunofluorescence showed stronger collagen I and osteopontin signals. RNA sequencing of knockout cells cultured under osteogenic conditions identified 186 upregulated and 90 downregulated genes in the loaded-membrane group compared with the unloaded membrane, using thresholds of absolute log2 fold change of at least 1 and adjusted p below 0.05. Pathway analysis highlighted PI3K/Akt signaling, while enriched biological processes included skeletal development, ossification and osteoblast differentiation.

Pharmacological experiments implicated both PI3K/Akt and ERK1/2 in the response. The loaded membrane increased phosphorylation of Akt and ERK1/2 and raised the measured spatial association between the two phosphorylated proteins. The PI3K activator 740Y-P further increased Akt phosphorylation and osteogenic outputs, whereas the PI3K inhibitor LY294002 reduced Akt phosphorylation, alkaline-phosphatase activity, mineralization and expression of osteopontin and osteocalcin.

The ERK inhibitor PD98059 reduced ERK1/2 phosphorylation without significantly changing Akt phosphorylation. Modulating PI3K/Akt produced corresponding changes in ERK1/2 phosphorylation. These results support a directional relationship in which PI3K/Akt influences ERK1/2 activation, but no genetic experiment was performed to establish the molecular link or distinguish direct from indirect effects.

In vivo, 8-week-old knockout mice received 3-millimetre cranial defects and were assigned to loaded-membrane, unloaded-membrane, free-vesicle or no-treatment groups, with wild-type mice serving as controls. Six male mice were included in each group at the four- and eight-week observation points, for 60 mice in the full study. Each loaded membrane contained 100 micrograms of vesicle protein; the free-vesicle group received repeated local injections, with the cumulative dose reaching 100 micrograms by the eighth injection.

Micro-computed tomography at four and eight weeks showed greater mineralized bone in defects treated with the loaded membrane than in the other knockout groups. At eight weeks, its bone surface area was 31.91 square millimetres, compared with 20.45 for free vesicles and 20.03 for the unloaded membrane. Maximum load reached 4.188 ± 0.316 newtons, significantly above the free-vesicle and unloaded-membrane groups and not significantly different from the wild-type value of 4.057 ± 0.357 newtons.

Untreated knockout defects lacked sufficient mineralized tissue for reliable load testing. Histology was consistent with the imaging findings. By eight weeks, defects supported by the loaded membrane showed continuous bridging, thicker and more compact trabeculae, reduced inter-trabecular spaces and areas resembling lamellar bone, whereas the other treated groups retained incomplete bridging and fibrous tissue.

Collagen I and osteopontin staining was strongest after membrane-mediated delivery. Immunohistochemistry indicated increased phosphorylated Akt and ERK1/2 in the loaded-membrane group, together with higher ATF4 and Runx2 expression. Examination of the heart, liver, spleen, lungs and kidneys found no reported inflammation or pathological damage at eight weeks.

The experiments therefore support a preclinical cell-free strategy combining exosome-mediated signaling with local biomaterial delivery, but they do not establish efficacy in people. The small-animal model, male-only cohort, eight-week observation period, absence of long-term and large-animal safety data, and inability of the protein-based release assay to distinguish intact vesicles from degraded exosomal protein remain important limitations.

Subject of Research: Preclinical testing of exosome-loaded nanofibrous membranes for p75NTR-associated bone-regeneration deficiency

Article Title: EMSCs-derived exosomes rescue p75NTR −/− -mediated osteogenesis deficiency via PI3K/Akt/ERK1/2 signaling pathways

Article References: Ye, J., Jin, X., Huang, Y., Khup, P. L., Yu, Y., Cheng, M., Yuan, Q., Xu, D., Nie, X., & Cheng, G. (2026). EMSCs-derived exosomes rescue p75NTR−/− -mediated osteogenesis deficiency via PI3K/Akt/ERK1/2 signaling pathways. Materials Today Bio, 41, Article 103755. https://doi.org/10.1016/j.mtbio.2026.103755

Image Credits: AI Generated

DOI: 10.1016/j.mtbio.2026.103755

Keywords: p75NTR, extracellular vesicles, bone regeneration, osteogenesis, nanofibrous membranes, PI3K/Akt signaling, ERK1/2 signaling, cranial defects, ectomesenchymal stem cells, EMSCs-derived, exosomes, rescue

The strategy addresses several features of osteoporotic bone loss at once. Osteoporosis involves an imbalance in remodeling, in which bone resorption by osteoclasts can exceed new bone formation by osteoblasts. The condition is also associated with chronic low-grade inflammation and oxidative stress, while macrophages and other immune cells help determine the local inflammatory environment. The researchers therefore designed a delivery system intended to carry a gene-regulating cargo to relevant bone cells, reduce reactive oxygen species, and dampen inflammatory signaling. This was an experimental nanomedicine approach tested in cultured cells and a mouse model, not a clinical treatment.

For the gene-regulating component, the investigators used a miR-196b inhibitor. Previous evidence cited in the paper showed that miR-196b-5p can inhibit osteoblast differentiation and influence both osteogenic and osteoclastic processes, including signaling associated with Sema3a, Wnt/β-catenin and the RANKL/OPG system. In the engineered particles, the inhibitor increased expression of GATA6, a downstream target used to verify miR-196 inhibition. M2 macrophage-derived exosomes were selected as the carrier because they provide an extracellular-vesicle delivery platform with reported immunomodulatory and osteogenic properties. Platinum nanoparticles were added for their enzyme-like antioxidant activity. The system was thus designed to combine RNA regulation, reactive oxygen species scavenging and alteration of the local osteoimmune environment in a single carrier.

The researchers characterized the engineered vesicles using transmission electron microscopy, nanoparticle tracking analysis, Western blotting and cell-viability assays. The M2-derived exosomes had a typical cup-shaped structure and an average diameter of 118.0 ± 43.9 nm, while the targeted, co-loaded formulation measured 139.2 ± 48.8 nm. Electron microscopy indicated that loading and targeting modifications did not visibly disrupt the vesicular membrane or cause obvious aggregation. HSP90, TSG101 and CD9 were detected as exosomal markers. No significant cytotoxicity was observed after 24 or 72 hours in the tested cell systems. Platinum-containing formulations showed stronger scavenging activity for hydrogen peroxide, hydroxyl radicals and superoxide than unmodified exosomes or blank controls, supporting the intended redox-buffering function of the nanoparticles.

Targeting was tested both in cultured cells and in mice. The SDSSD peptide was selected because it binds periostin, a ligand associated with osteoblast targeting. Confocal microscopy showed that BT-modified exosomes were taken up preferentially by MC3T3-E1 osteoblast-lineage cells compared with RAW264.7 macrophages. After intravenous administration of fluorescently labeled particles, BT-Exos accumulated more strongly in femur sections than unmodified exosomes. Ex vivo imaging of the brain, heart, liver, spleen, lungs, kidneys, tibiae and femora likewise showed stronger skeletal fluorescence and reduced distribution in other organs for the targeted formulation. The authors interpret these findings as evidence of preferential bone accumulation, although the experiments did not establish the complete fate of the particles or the precise cellular route of uptake. The delivery advantage was therefore demonstrated under the study’s experimental conditions rather than as a general property of all exosome formulations.

In inflammatory cell assays, the components produced complementary effects. Platinum-containing formulations showed the greatest intracellular ROS-scavenging performance, while M2-derived exosomes reduced the expression of the pro-inflammatory cytokines interleukin-1β, interleukin-6 and tumor necrosis factor-alpha. Combining the exosome, platinum and miR-196 inhibitor produced the strongest overall reductions in cytokine expression, with quantitative reverse-transcription PCR agreeing with the fluorescence measurements. Comparisons of exosomes from M0, M1 and M2 macrophages also showed that M1 and M2 exosomes increased alkaline phosphatase activity and mineralization relative to controls, but only M2 exosomes significantly increased RUNX2 expression, the osteogenic transcription factor used by the researchers to justify the choice of carrier. These results support the rationale for using M2-derived vesicles, while not establishing that the formulation will produce the same effects in human bone tissue.

The targeted particles promoted osteoblast development in vitro. After seven days of osteogenic induction, the fully engineered formulation produced the strongest alkaline phosphatase staining; after 14 days, treated cultures showed greater calcium deposition by Alizarin Red S staining than controls. Western blotting showed progressively higher RUNX2 and ALP protein levels across the treatment groups, with BT-Exo-Pt-miR-196 inhibitor highest among them. Immunofluorescence measurements of osterix and osteocalcin followed the same pattern. Quantitative proteomics of MC3T3-E1 cells treated with BT-Exo-miR-196 inhibitor identified 605 up-regulated and 531 down-regulated proteins relative to control, with six biological replicates per group. Increased proteins included SP7, LRP5 and RUNX2, together with matrix-related proteins POSTN, BGN and LOX, while innate immune and cytokine-associated proteins including TBK1, P2RX7, C3, CGAS, TLR2, PTGS2 and ISG15 decreased. Pathway enrichment indicated changes involving mitochondrial and respiratory-chain proteins, extracellular matrix processes and immune signaling. These measurements are cellular and biochemical observations, not evidence of fracture healing in people.

Osteoclast formation was also reduced in laboratory cultures. Bone-marrow-derived macrophages exposed to osteoclast-inducing conditions developed fewer TRAP-positive multinucleated cells after treatment with the engineered formulations, and the untargeted co-loaded exosome produced the lowest osteoclastogenesis in that assay. Phalloidin staining showed weaker F-actin ring formation, while Western blot and gene-expression measurements showed lower levels of osteoclast-associated markers, including NFATc1, cathepsin K, MMP9 and TRAP. The untargeted result was not considered a contradiction: the SDSSD peptide binds periostin on osteoblasts and was not designed to bind osteoclast precursors. Its benefit in the animal model was therefore interpreted as preferential delivery to bone surfaces and remodeling regions rather than direct targeting of osteoclasts. In other words, the targeting strategy appeared useful for concentrating the therapy in the bone microenvironment, but the osteoclast cultures did not provide evidence that the peptide directly targets osteoclasts.

In the in vivo experiment, eight-week-old female C57BL/6 mice were assigned to sham-operated, ovariectomized, untargeted-treatment and targeted-treatment groups, with five animals per group. Treatments began two weeks after surgery and involved tail-vein injections every three days for six weeks. Each treatment dose contained 100 μL of PBS with 1.0 × 10^11 particles/mL, and the ovariectomy-only group received PBS on the same schedule. Micro-CT of the distal femur showed that ovariectomy reduced bone mineral density and trabecular bone volume fraction, increased trabecular separation and reduced trabecular thickness and number. Both nanoparticle treatments partially reversed these changes, but the targeted formulation produced the most pronounced preservation of trabecular architecture. H&E and Masson trichrome staining supported the imaging results by showing improved trabecular organization and matrix deposition. TRAP staining showed the least osteoclast-positive area after targeted treatment, while osteocalcin and osterix measurements indicated stronger osteogenic activity and cathepsin K staining indicated reduced osteoclast-associated activity. The experiment therefore showed improved preservation of bone structure and remodeling markers in this model, rather than complete restoration of a healthy skeleton or prevention of fractures.

The study also reported an initial biosafety signal. White blood cell, red blood cell and platelet counts did not differ significantly among the groups. Serum ALT, AST, blood urea nitrogen and creatinine remained within the reported ranges, and histological examination of the heart, liver, spleen, lungs and kidneys showed no obvious inflammatory infiltration, necrosis or structural damage. These findings support short-term tolerability in this mouse model, but they are not a comprehensive translational safety assessment. The exosomes are cell-derived biological products with possible batch variability, immunogenicity and manufacturing challenges, while the platinum nanoparticles are not enzymatically degraded and may persist in internal organs. Longer observation, dose-escalation studies, quantitative clearance analysis and tests for anti-exosome immune responses remain necessary. Overall, the findings identify an experimental strategy for coordinating bone formation, osteoclast suppression, oxidative-stress control and inflammatory modulation, but its efficacy and safety in humans remain untested.

Subject of Research: Experimental bone-targeted exosome delivery for ovariectomy-induced osteoporosis in mice

Article Title: Engineering exosomes-mediated RNA delivery regulates bone homeostasis and alleviates osteoporosis

Article References: Du, Y., Zhang, Y., Wang, Z., Jiang, H., Li, L., Liu, X., Zhou, P., Huang, X., Liu, J., Li, Z., & Li, Z. (2026). Engineering exosomes-mediated RNA delivery regulates bone homeostasis and alleviates osteoporosis. Materials Today Bio, 41, Article 103758. https://doi.org/10.1016/j.mtbio.2026.103758

Image Credits: AI Generated

DOI: 10.1016/j.mtbio.2026.103758

Keywords: osteoporosis, exosomes, miR-196b inhibition, bone targeting, platinum nanoparticles, osteogenesis, osteoclastogenesis, oxidative stress, nanomedicine, mouse model, Engineering, exosomes-mediated

To understand why this gap matters, it helps to appreciate what actually happens when a wound closes. The outermost layer of the skin, the epidermis, is restored through a process called re-epithelialization, which depends on keratinocytes, the dominant cell type of the epidermis, located at the wound edge. These cells must undergo a remarkable sequence of behaviors: they activate, detach from their neighbors, migrate across the wound bed, proliferate to replenish the migrating front, and then—critically—redifferentiate back into their mature state, reassembling cell junctions and restoring the layered barrier structures that keep microbes out and moisture in. Each stage of this choreography is vulnerable to disruption, and in diabetes, the high-glucose environment and its downstream pathological consequences interfere at nearly every step, which is why diabetic wounds so often stall in a chronic, non-healing state.

One of the review’s most important conceptual contributions is its argument about how this process should be described in the first place. For years, wound biologists have leaned on the framework of epithelial–mesenchymal transition, or EMT, a binary model in which epithelial cells are thought to convert wholesale into migratory, mesenchymal-like cells and then switch back. The authors contend that this binary picture does not accurately capture what keratinocytes actually do during repair. Instead, they argue, the phenomenon is better described as epithelial–mesenchymal plasticity, or EMP—a spectrum of transient, reversible, and stage-dependent phenotypic states rather than an all-or-nothing switch. This distinction is not merely semantic. If keratinocytes occupy a continuum of hybrid states during migration and then slide back toward full epithelial identity as the barrier reforms, then therapies must be evaluated not just for whether they speed up closure, but for whether they support the full, coordinated sequence of state changes, including the final redifferentiation and junction reassembly that produce a functional barrier.

Exosomes and other small extracellular vesicles have captured the imagination of wound-healing researchers precisely because they are nature’s own intercellular delivery vehicles. These lipid-enclosed nanoparticles carry proteins, lipids, and RNA molecules from their cell of origin to recipient cells, and in doing so they can reprogram the behavior of the cells they reach. In the context of diabetic wounds, the review explains, sEVs may support re-epithelialization through two broad routes. The first is direct: vesicles could act on keratinocytes themselves, influencing their repair programs—promoting migration, stimulating proliferation, and potentially guiding the redifferentiation and junction formation needed for barrier recovery. The second is indirect: vesicles derived from stem cells, immune cells, or other sources could remodel the hostile wound microenvironment, dampening chronic inflammation, encouraging new blood vessel growth, reducing oxidative stress, and improving the extracellular matrix scaffold on which migrating keratinocytes depend.

The indirect route is where the bulk of the experimental evidence currently sits, and this is the crux of the review’s critique. Most published studies of exosome or sEV therapy in diabetic wound models measure endpoints such as overall wound closure, histological re-epithelialization, angiogenesis, inflammatory marker changes, or collagen deposition. These outcomes are meaningful, and improvements in them justify continued enthusiasm for the approach. But they are, by their nature, downstream or parallel consequences of therapy. They do not tell researchers whether the vesicles actually engaged the keratinocyte plasticity program itself—whether they nudged cells through the EMP-associated state transitions, supported epithelial redifferentiation, and produced genuine, durable barrier recovery in diabetic wound keratinocytes. On that direct question, the authors find the evidence remains limited, and they are candid about the implications for how the field should interpret its own successes.

To bring analytical clarity to a literature of uneven depth, the review proposes a four-tier framework for grading the evidence. The highest tier is direct EMP evidence: studies that track the actual phenotypic state transitions of keratinocytes in diabetic wounds under sEV treatment. The second tier is functional keratinocyte evidence: demonstrations that vesicles measurably alter keratinocyte migration, proliferation, redifferentiation, or barrier-forming capacity, even if the full plasticity trajectory is not mapped. The third tier is indirect microenvironmental support: the well-populated category of studies showing improved inflammation, vascularization, oxidative balance, or matrix remodeling. The lowest tier is mechanistic inference, where benefits are observed but the cellular mechanism is assumed rather than demonstrated. This hierarchy gives researchers, reviewers, and clinicians a shared vocabulary for assessing how mature any given line of evidence really is—a tool the field has arguably lacked as publications on vesicle therapies have multiplied.

The review also confronts the practical and translational dimensions that will determine whether laboratory promise becomes bedside reality. Engineered vesicles—vesicles whose cargo or surface properties have been deliberately modified to enhance potency, targeting, or stability—represent one active frontier, offering the possibility of tailoring sEV therapies to specific stages of the repair sequence. Local delivery systems are another: because free vesicles can diffuse away, degrade, or be cleared rapidly from a wound bed, biomaterial-based depots, hydrogels, and scaffolds designed to retain and release vesicles at the wound site are being explored as ways to sustain therapeutic concentrations. Yet each of these strategies introduces its own questions about manufacturing consistency, dose standardization, safety, and regulatory classification, and the review treats evidence maturity and translational risks as inseparable from the biology itself.

The stakes of getting this right are considerable. A therapy that accelerates wound closure but leaves behind a fragile, poorly differentiated epidermis could set patients up for re-ulceration, the dreaded cycle that defines much of diabetic foot disease. Conversely, a therapy that genuinely guides keratinocytes through the full EMP arc—from activation and migration through redifferentiation and junction restoration—would address the fundamental cellular failure of chronic diabetic wounds rather than merely palliating the environment around it. This is why the authors insist that future studies move beyond wound-area measurements and incorporate readouts of keratinocyte state, epithelial stratification, and barrier function. The distinction between a closed wound and a healed one is, in diabetic skin, the difference between temporary reprieve and durable recovery.

For now, the review’s overall verdict is a calibrated one. Exosome and small extracellular vesicle therapies have earned their place among the most promising strategies for diabetic wound healing, with plausible mechanisms spanning direct keratinocyte support and broad microenvironmental remodeling. The multiple microenvironmental effects documented across preclinical studies are real and encouraging. But the field’s central claim—that these vesicles can deliberately guide the plasticity program that rebuilds the epidermal barrier—still rests more on inference than on direct demonstration. By naming the gap precisely, proposing a framework to close it, and mapping the engineering and delivery challenges ahead, the review offers the field something more valuable than another positive result: a clear picture of what must be proven before exosome therapy can be trusted to heal, and not merely close, the wounds of diabetic patients.

As vesicle-based therapeutics advance toward clinical testing, the EMP framework articulated in this review is likely to shape how the next generation of experiments is designed. Studies that track keratinocyte state transitions directly, validate functional barrier recovery, and report evidence maturity transparently will be the ones that determine whether exosome therapy fulfills its promise for the patients who need it most—those whose wounds have run out of options.

Subject of Research: Exosome and small extracellular vesicle therapy for diabetic wound re-epithelialization and epithelial–mesenchymal plasticity

Article Title: Exosome/sEV therapy for diabetic wounds: Promise and evidence gaps in re-epithelialization

Article References: Exosome/sEV therapy for diabetic wounds: Promise and evidence gaps in re-epithelialization. Original publication (Bibliographic details unavailable.)

Image Credits: AI Generated

DOI: Not provided

Keywords: exosomes, small extracellular vesicles, diabetic foot ulcers, wound healing, re-epithelialization, keratinocytes, epithelial-mesenchymal plasticity, epidermal barrier, regenerative medicine, stem cell therapy, drug delivery, Skin journal

The appeal of these vesicles lies in their biology. Because they carry a selective cargo of proteins, lipids and non-coding RNAs that mirror their parent cell, vesicles shed by diseased neurons act as molecular messengers of brain pathology. Their lipid bilayer protects this cargo from enzymatic degradation in the bloodstream, allowing long-term biobanking, while their membranes can fuse with biological barriers and slip across the blood–brain barrier into peripheral circulation. Once there, they can be harvested from a simple blood draw, cerebrospinal fluid, urine or saliva, turning what was once inaccessible central pathology into a minimally invasive liquid biopsy.

The review, which searched PubMed, Web of Science and Embase from database inception to January 2026, distilled roughly 26 studies into primary clinical biomarker evidence, supported by about 15 mechanistic investigations. Alzheimer’s disease features most prominently. Pathological amyloid-beta plaques and phosphorylated tau tangles begin accumulating 15 to 20 years before symptoms appear, making early detection critical. Longitudinal work by Kapogiannis and colleagues in the Baltimore Longitudinal Study of Aging showed that neuron-derived vesicles from people who later developed Alzheimer’s carried elevated p-tau181, p-tau231 and phosphorylated IRS-1, with a multiplexed model achieving an area under the curve of 0.896 in training and 0.800 in testing cohorts.

Subsequent studies strengthened the case. Jia and colleagues found that Aβ42, total tau and p-tau181 in immunoenriched plasma vesicles performed comparably to established cerebrospinal fluid biomarkers, with a combined validation AUC of 0.980 for distinguishing Alzheimer’s patients from healthy controls. Beyond the canonical toxic proteins, vesicle-borne synaptic proteins such as synaptopodin and synaptophysin decreased in both Alzheimer’s and frontotemporal dementia, and importantly correlated with cognitive scores, whereas Aβ42 and p-tau181 did not. A p-tau396 signal that rises in Alzheimer’s but stays at baseline in frontotemporal dementia offers a potential differential marker, while declines in the complement regulator CD59 in astrocyte-derived vesicles and shifts in lysosomal proteins such as cathepsin D point to neuroinflammation and endolysosomal dysfunction years before clinical onset.

Parkinson’s disease tells a parallel story built around α-synuclein, the protein whose intracellular aggregation defines the disorder. Jiang and colleagues reported that α-synuclein in serum neuron-derived vesicles was approximately two-fold higher in Parkinson’s patients than in controls, achieving an AUC of 0.86, and, strikingly, was already elevated in people with rapid eye movement sleep behavior disorder, a prodromal condition. Adding clusterin to form an α-synuclein-to-clusterin ratio pushed differential diagnostic accuracy to 0.980 against other proteinopathies and 0.940 against multiple system atrophy. A later meta-analysis confirmed elevated total α-synuclein across plasma vesicle studies, and proteomic profiling by Kitamura and colleagues identified vesicle-associated apolipoprotein A1 as strongly and negatively correlated with Hoehn and Yahr disease stage.

Non-coding RNAs add a second analytical dimension. In cerebrospinal fluid vesicles, a miR-153 and miR-409-3p combination reached an AUC of 0.990 for Parkinson’s discrimination, while a serum panel of miR-19b, miR-24 and miR-195 achieved 0.946. Bioinformatic screening by He and colleagues went further, mapping serum vesicle microRNAs onto Hoehn–Yahr stages: miR-374a-5p and miR-374b-5p rose across all active phases, miR-199a-3p fell specifically at stage II, miR-28-5p peaked at stage III, and miR-22-5p and miR-151a-5p diverged at stage IV, hinting at non-invasive molecular staging of a disease currently assessed largely by clinical examination.

The review extends this logic across the wider neurological spectrum. In acute ischemic stroke, vesicle SIRT2 achieved an AUC of 0.838, miR-134 correlated with both stroke severity scores and infarct volume, and miR-422a distinguished acute from subacute phases with an AUC of 0.957, while a five-circular-RNA brain-vesicle panel reached 0.921 with 95 percent sensitivity. In glioma, where tissue diagnosis currently requires surgery, vesicle EGFRvIII transcripts detected high-grade tumors with roughly 80 percent accuracy, and a three-circular-RNA signature distinguished high-grade astrocytoma from controls with perfect accuracy in a small single-center cohort. In multiple sclerosis, vesicle myelin oligodendrocyte glycoprotein rose during relapses, and a miR-122-5p and miR-196b-5p panel separated relapsing patients from remission with an AUC of 0.866. In Huntington’s disease, mutant huntingtin was detectable in plasma neuron-derived vesicles, and a combined model of tRF-Gly-GCC, miR-27a-3p and neurofilament light chain distinguished premanifest carriers with an AUC of 0.908. In amyotrophic lateral sclerosis, vesicle TDP-43 separated patients from controls with AUCs of 0.94 to 0.99 across two independent cohorts.

Yet the review is notably candid about the field’s unresolved problems. Signals overlap across diseases: miR-21 rises both in glioma and in the subacute phase of stroke, and neurofilament light chain climbs in Alzheimer’s, ALS, Huntington’s and stroke alike, suggesting these molecules may reflect shared processes such as neuroinflammation and axonal injury rather than specific entities. Attribution is equally thorny. The L1CAM immunocapture technique widely used to isolate neuron-derived vesicles from blood was challenged by Norman and colleagues, who found L1CAM mostly in soluble protein fractions, though a later single-vesicle study found L1CAM-positive vesicles co-expressing neuronal markers in 30 to 63 percent of cases. Blood vesicles are also overwhelmingly derived from blood cells and endothelium, so CNS signals may be diluted or confounded by peripheral contributions.

Standardization and validation gaps loom just as large. Pre-analytical factors such as fasting, platelet activation during venipuncture, hemolysis, lipoprotein contamination and freeze–thaw cycles can all distort vesicle measurements, and isolation techniques trade purity against yield. Although a systematic review of 471 vesicle-related clinical trials found that nearly half assess diagnostic applications, only 11 percent examined vesicle subpopulations, and reporting of isolation methods remains incomplete. Exceptional results, such as 100 percent accuracy in small cohorts, may reflect overfitting rather than clinical readiness. The authors point to the urinary ExoDx Prostate assay, which earned FDA Breakthrough Device Designation after prospective validation, as a template, and call for standardized MISEV2023-compliant workflows, covariate adjustment, and prospective multicenter validation before brain-derived vesicle panels can move from promising research candidates to clinically deployable diagnostics.

Subject of Research: Extracellular vesicles as liquid biopsy biomarkers for diagnosing central nervous system diseases

Article Title: Utility of extracellular vesicles in the diagnosis of central nervous system diseases

Article References: Wang, M., Yang, J., Gao, C., Qu, S., Mi, H., Guo, Y., Gui, T., & Gai, Z. (2026). Utility of extracellular vesicles in the diagnosis of central nervous system diseases. Frontiers in Neurology, 17, Article 1959745. https://doi.org/10.3389/fneur.2026.1959745

Image Credits: AI Generated

DOI: 10.3389/fneur.2026.1959745

Keywords: extracellular vesicles, liquid biopsy, blood-brain barrier, Alzheimer's disease, Parkinson's disease, biomarkers, neurodegenerative disease, stroke, glioma, multiple sclerosis, amyotrophic lateral sclerosis, exosomes

Extracellular vesicles are small, membrane-delimited particles released by virtually all cell types. Unlike soluble signaling molecules such as myokines, which have traditionally dominated models of muscle-to-organ communication, EVs carry complex cargo: proteins, lipids, nucleic acids, and metabolites that reflect the physiological state of the cell that produced them. When a muscle cell releases an EV, it is effectively exporting a molecular snapshot of its own condition. Recipient cells can take up these vesicles and alter their behavior in response, making EVs a sophisticated channel for interorgan dialogue rather than a one-way broadcast of isolated chemical messengers.

The review describes experimental evidence that muscle EVs enter the circulation. Using a myofiber-specific fluorescent reporter mouse, researchers demonstrated that vesicles released by skeletal muscle fibers reach the blood. Complementary work linked mechanical loading of muscle to the delivery of EV-associated microRNA-1 to white adipose tissue, where it promoted lipolysis. Within muscle itself, satellite cells, the resident stem cells responsible for repair, release vesicles that carry microRNA-206 to fibrogenic neighbors, restraining excessive scar tissue formation during muscle growth. These local interactions established the groundwork for asking whether muscle EVs could also act at a distance.

The clearest proof of concept for long-range EV signaling comes from the muscle-bone axis. In cell culture, vesicles from muscle cells were shown to promote osteogenic differentiation of bone precursor cells by delivering microRNA-27a-3p, which activates beta-catenin signaling. More strikingly, in vivo studies identified skeletal muscle-derived EVs that enter the circulation, home to bone, and are taken up by bone marrow stromal cells, where they deliver glycolytic enzymes such as lactate dehydrogenase A to boost energy metabolism and protect mice from disuse osteoporosis. Crucially, this communication channel is state-dependent: vesicles from atrophic muscle do the opposite, suppressing bone-forming activity in osteoblasts. Muscle-targeted blockade of EV generation in atrophic animals restored osteoblast function and alleviated bone loss, demonstrating that the same route can carry either supportive or destructive messages depending on the condition of the sending muscle.

The muscle-brain axis is younger but advancing quickly. In defined culture systems, vesicles from muscle cells enhanced survival and neurite outgrowth of motor neuron-like cells. An engineered neuromuscular tissue model showed that innervation and glutamate stimulation increase EV release from muscle and alter exosomal microRNA cargo, and that the resulting vesicles boost neuronal network activity, dendritic branching, and axonal transport in hippocampal cultures. In a separate injury model, preconditioning exercise increased exosomal microRNA-484, derived mainly from skeletal muscle, which reduced neuronal ferroptosis after ischemic brain injury by suppressing the ACSL4 pathway. Muscle-derived exosomes were tracked to the ischemic penumbra and taken up by neurons, and blocking muscle production of the microRNA weakened the neuroprotective effect of exercise. In an Alzheimer’s disease mouse model, exercise-induced muscle EVs were taken up by microglia, promoting a disease-associated state that enhanced amyloid-beta plaque clearance through microRNA-378a-3p-mediated regulation of lipid metabolism.

Tumor cells appear to be listening as well. In vitro, vesicles from differentiated muscle cells were taken up by lung carcinoma cells and reduced their viability, proliferation, and migration while increasing markers of apoptosis, with proteomic analysis identifying decorin as an enriched cargo candidate. More directly, recent work in Drosophila and mouse cancer models showed that healthy skeletal muscle releases vesicles with tumor-suppressive activity, partly mediated by microRNA-7a-5p inhibition of TEAD1 signaling in tumor cells. Muscle cell-derived vesicles have also been shown to dampen inflammatory gene expression in cultured macrophages by increasing IRG1 expression and itaconate production, hinting at an immunoregulatory dimension to the system, though whether this occurs in distal tissues during aging remains untested.

Aging, the review argues, remodels this entire communication network at three levels: vesicle production, cargo composition, and downstream effects on recipient cells. In human primary muscle cells, vesicles from older donors showed altered proteomic and biochemical signatures, including enrichment of proteins tied to oxidative stress and DNA and RNA mutagenesis, even when basic vesicle parameters looked normal. In the bone axis, age-related shifts are well documented: a muscle-associated circulating vesicle population carries increased microRNA-34a with age, promoting senescence in bone marrow stromal cells, while vesicles from aged or atrophic muscle deliver microRNA-125a-5p, which suppresses the Sirt7-Sp7 osteogenic axis in osteoblasts. In the tumor axis, sarcopenic muscle secretes fewer vesicles with altered cargo, losing the protective microRNA-7a-5p signal, a decline traced to an age-sensitive NOTCH-SDC2 pathway that governs muscle EV biogenesis.

Exercise emerges as the most promising physiological countermeasure. In the Alzheimer’s model, swimming-induced muscle vesicles enhanced microglial plaque clearance and improved cognition, and vesicles engineered to overexpress microRNA-378a reproduced the cognitive benefit when administered directly, a proof of principle that protective exercise signals can be mimicked. Resistance training in older adults increased several circulating EV-associated microRNAs toward youthful levels, while in aged mice exercise restored NOTCH-SDC2 signaling, boosted vesicle release and microRNA-7a-5p cargo, and reduced tumor growth. Metabolic state matters too: overexpression of PGC-1alpha in human myotubes enriched vesicles with antioxidant-related messenger RNAs that enhanced protective responses in cultured endothelial cells, suggesting that donor-cell metabolism shapes cargo and function. Additional mechanistic leads include EV-associated mitochondrial DNA engaging cGAS-STING signaling in recipient cells, and stress-driven unfolded protein response pathways in muscle altering vesicle cargo, both flagged as priorities for future investigation.

The therapeutic implications cut in two directions. Protective vesicular signals that decline with age could be restored or mimicked, as the microRNA-378a experiment demonstrates. Maladaptive signals from aged muscle could be selectively blocked, as shown by cargo-directed interventions that preserved bone formation. But the authors caution that broad suppression of EV production is risky, since the same vesicles can carry beneficial cargo for bone, brain, and tumor defense. Rigorous methodology is also essential: different isolation techniques recover different mixtures of vesicles and non-vesicular material, and confirming that vesicles truly originate from muscle, reach the proposed recipient cells, and account for observed effects remains the central challenge. As the field matures, skeletal muscle-derived extracellular vesicles may prove to be not just biomarkers of aging, but rational intervention targets for the multi-organ decline that accompanies it.

Subject of Research: Skeletal muscle-derived extracellular vesicles as mediators of interorgan communication during aging

Article Title: Skeletal Muscle‐Derived Extracellular Vesicles in Interorgan Communication During Aging

Article References: Jiang, W., Chua, K., Young, J., Tan, E. K., & Tang, H.-W. (2026). Skeletal Muscle‐Derived Extracellular Vesicles in Interorgan Communication During Aging. Aging Cell, 25(10), Article e70773. https://doi.org/10.1111/acel.70773

Image Credits: AI Generated

DOI: 10.1111/acel.70773

Keywords: extracellular vesicles, skeletal muscle, aging, sarcopenia, muscle-bone crosstalk, muscle-brain axis, tumor suppression, microRNA, exercise, osteoporosis, Alzheimer's disease, exosomes

The scale of the problem is staggering. An estimated 2.21 in every 1,000 people worldwide live with chronic wounds, which typically persist for twelve to thirteen months and recur in as many as 60 to 70 percent of patients. Diabetic ulcers are among the worst offenders, and their origins lie in a fundamental breakdown of coordination. Normal wound healing unfolds in four precisely choreographed phases—hemostasis, inflammation, proliferation, and remodeling—and when any phase falls out of step, the entire repair program can stall. The new review, led by Keerthan Nayak and colleagues at Manipal Academy of Higher Education, maps how autophagy governs this choreography and where it goes wrong in diabetic and non-healing wounds.

At the molecular level, autophagy is a lysosome-dependent degradation pathway conserved across virtually all eukaryotic life. In its best-studied form, macroautophagy, a membrane structure called a phagophore expands to engulf cytoplasmic cargo, sealing it inside a double-membrane vesicle known as an autophagosome. This vesicle then fuses with a lysosome to form an autolysosome, where hydrolytic enzymes dismantle the contents. The process runs through a defined molecular assembly line: the ULK1 complex initiates the cascade, a class III PI3K complex containing Beclin-1 generates phosphatidylinositol-3-phosphate at the assembly site, and the ATG5-ATG12-ATG16L1 conjugation system drives lipidation of the protein LC3, expanding the autophagosome membrane. Final fusion with lysosomes depends on the small GTPase RAB7 and SNARE proteins.

What makes autophagy so relevant to wounds is the way it is switched on and off. Under nutrient-rich conditions, the pathway is suppressed by mTORC1, the mammalian target of rapamycin complex 1, acting through the PI3K-AKT signaling axis. When cells face the opposite conditions—hypoxia, oxidative stress, ATP depletion, nutrient scarcity, precisely the conditions inside an open wound—AMP-activated protein kinase, or AMPK, takes command. AMPK inhibits mTORC1 and directly phosphorylates ULK1 and Beclin-1 to ignite autophagy. In other words, the wound microenvironment is almost purpose-built to activate the very pathway that helps cells survive it.

The review details autophagy’s role in each phase of healing. During inflammation, pattern recognition receptors such as toll-like receptors and the NOD-like receptors NOD1 and NOD2 stimulate autophagy after sensing microbial invasion, promoting the engulfment and destruction of pathogens in a process called xenophagy. Autophagy also shapes the inflammatory signal itself: in macrophages, secretory autophagy promotes the release of the inflammatory messengers IL-1β and HMGB1, while the pathway helps steer macrophages from their pro-inflammatory M1 state toward the pro-repair M2 state. That switch, however, is context-dependent. In diabetic settings, advanced glycation end-products can drive autophagy toward harmful M1 polarization via IRF8, actually impairing wound closure.

In the proliferative phase, autophagy keeps the repair machinery moving. Hypoxia in the wound bed raises reactive oxygen species, which activate p38 and JNK MAPK signaling and trigger BNIP3-mediated autophagy in keratinocytes, facilitating their migration across the wound and accelerating re-epithelialization. Experiments comparing keratinocytes lacking the essential autophagy gene Atg7 with normal cells showed that autophagy-deficient cells are far more vulnerable to oxidative stress, accumulating DNA damage and slipping into premature senescence. Hypoxia-driven autophagy also preserves endothelial cell function and promotes angiogenesis, ensuring new blood vessels reach the healing tissue. During the final remodeling stage, autophagy regulates fibroblast differentiation into myofibroblasts, collagen maturation, and even the clearance of cells that would otherwise drive hypertrophic scarring.

The translational implications are where the review becomes genuinely provocative, because a growing arsenal of drugs and materials can now manipulate the pathway. Rapamycin, the classic mTORC1 inhibitor, accelerates healing and reduces scarring in rodent models, and mesenchymal stem cells primed with rapamycin release exosomes that enhance diabetic wound repair by promoting VEGF-driven angiogenesis and shifting macrophages toward the M2 phenotype. Metformin, the world’s most widely prescribed diabetes drug, activates AMPK; topical metformin gels raised markers of autophagy such as LC3B and Beclin-1 and improved collagen deposition and re-epithelialization in diabetic rats. Plant-derived compounds add to the list: resveratrol protects diabetic wounds by modulating PI3K/AKT/Nrf2 signaling and blocking ferroptosis, green tea’s epigallocatechin gallate restores impaired autophagic flux in high-glucose-treated keratinocytes through AMPK/ULK1, and curcumin’s protective effects in stressed fibroblasts vanish entirely when autophagy is blocked.

Biomaterials are emerging as perhaps the most elegant delivery solution. Zwitterionic sulfobetaine methacrylate hydrogels promote near-complete skin regeneration by dampening PI3K/AKT/mTOR signaling, while thermosensitive injectable hydrogels pairing zinc with metformin raised LC3 expression at the wound site and sped full-thickness skin repair. Electrospun chitosan nanofibers loaded with the antioxidant dihydromyricetin boosted autophagy-associated proteins including LC3-II, ATG5, and ATG7 while suppressing inflammation. Even strategies that inhibit autophagy have a place: PLGA microspheres releasing platelet-derived growth factor can suppress excessive autophagy in endothelial cells and fibroblasts, unleashing angiogenesis and granulation tissue formation. The common thread is localization—delivering the right modulator to the right cells at the right time, with minimal systemic exposure.

Yet the authors are candid about the obstacles standing between the laboratory and the clinic. Most autophagy-modulating compounds suffer from poor solubility, limited skin penetration, instability, and off-target effects that ripple through inflammation, cell proliferation, and angiogenesis. Rapamycin’s immunosuppression and metabolic side effects, for instance, mean even topical use demands caution. More fundamentally, much of the preclinical evidence rests on static marker readouts such as LC3 puncta or Beclin-1 levels, which cannot distinguish genuine autophagic flux from a blocked degradation step. The review calls for rigorous flux assays, including bafilomycin A1 inhibition and tandem fluorescent LC3 reporters, alongside well-controlled human trials that remain scarce. There are also open biological questions: whether chronic wounds fail at autophagy initiation or lysosomal clearance, which cell types to target at each phase, and whether selective pathways such as mitophagy and ER-phagy outperform general autophagy manipulation.

The bigger picture emerging from this synthesis is that autophagy is neither uniformly good nor bad for healing—it is a dial that must be tuned. Too little autophagy leaves cells unable to adapt to the hostile wound environment; too much, particularly in chronic diabetic wounds, can feed pathological inflammation and fibrosis. The authors argue the therapeutic goal should be restoring normal autophagic flux in the correct cells, wound type, and healing stage, ideally using smart biomaterials capable of controlled, sequential drug release. If that precision can be achieved, the humble cellular recycling system may finally deliver what millions of patients with non-healing wounds have been waiting for: a way to turn stalled, inflamed wound beds back into regenerating tissue.

Subject of Research: The role of autophagy in cutaneous wound healing and therapeutic strategies targeting it

Article Title: Rewiring autophagy to target cutaneous wound healing: investigation of molecular mechanisms to therapeutic interventions

Article References: Nayak, K., Banerjee, I., Nazerulla, F., Valame, A., Paul, M. K., Bhutia, S. K., Basu, D., & Mukhopadhyay, S. (2026). Rewiring autophagy to target cutaneous wound healing: investigation of molecular mechanisms to therapeutic interventions. Molecular Biology Reports, 53(1), Article 1751. https://doi.org/10.1007/s11033-026-12938-w

Image Credits: AI Generated

DOI: 10.1007/s11033-026-12938-w

Keywords: autophagy, wound healing, chronic wounds, diabetic ulcers, mTOR, AMPK, macrophage polarization, keratinocytes, angiogenesis, phytochemicals, biomaterials, exosomes

The modern story begins in the mid-1980s, when a series of papers challenged the assumption that radiation damage expressed itself only in the first divisions after exposure. Researchers demonstrated that lethal mutations and chromosomal aberrations could appear in distant progeny of irradiated cells, after many apparently normal divisions. Because the damage was lethal and non-clonal, it could not have been carried by the cells themselves; instead, the genome had become less able to eliminate or correct mistakes. This phenomenon is now known as radiation-induced genomic instability, or RIGI. The second pillar of NTE research came in 1992, when Nagasawa and Little exposed Chinese hamster ovary cells to such a low fluence of alpha particles that fewer than 1 percent of cell nuclei were directly traversed, yet sister chromatid exchanges appeared in roughly 30 percent of the population. Radiation-induced bystander effects, or RIBEs, were born: signals produced by irradiated cells could induce damage in unexposed neighbors.

Subsequent decades established the reality of bystander signaling using a suite of experimental protocols. Medium transfer experiments showed that culture medium harvested from irradiated cells could reduce the clonogenic survival of unirradiated recipients. Microbeam studies, in which single cells were targeted with counted particles, revealed that damage signals spread up to a millimeter away from the hit site. Transwell systems, in which irradiated and unirradiated cultures shared medium but not physical contact, confirmed that soluble factors were involved. Whole-animal models extended the phenomenon beyond the dish. Strikingly, the review documents that effects of this kind were recorded as early as 1968, when plasma from patients receiving X-ray therapy or total-body irradiation was shown to induce chromosomal aberrations in cultured lymphocytes from healthy donors, and again in 1977 with plasma from atomic bomb survivors. The phenomena were variously called indirect, abscopal, clastogenic or out-of-field effects, but all involved damage at sites in space or time that received no energy deposition.

How does a radiation hit in one cell produce DNA damage in another? The first mechanistic answer came from Little’s laboratory, which showed that gap junction intercellular communication, or GJIC, was involved in bystander signaling after alpha-particle irradiation. The inhibitor lindane suppressed the effect, and connexin proteins forming the junctions were upregulated in cultures exposed to ultra-low fluences. But GJIC could not explain medium transfer experiments, where the signal survived in culture medium for hours. The leading explanation there involved reactive oxygen species and reactive nitrogen species generated by direct irradiation, which induced secondary damage in surrounding cells. Yet ROS and NOS are short-lived, so they too could not fully account for medium transfer, which triggers apoptosis, calcium release, mitochondrial membrane depolarization and caspase activation in recipients. The review notes that no single magic factor was ever characterized; some experiments from the authors’ group suggested the bystander effect might actually arise from a loss of factors rather than active secretion, with serotonin naturally present in serum bound by irradiated cells and triggering downstream calcium release in recipients.

Mitochondria have emerged as central players in this signaling web. Lyng and colleagues reported mitochondrial membrane depolarization as a robust marker of bystander signaling, and altered energy production was documented in both targeted and non-targeted cells. Nugent and colleagues measured direct effects on mitochondrial DNA and increased mitochondrial mass in cells with functionally compromised mitochondria after both direct gamma radiation and bystander factors. A particularly striking line of work from the McMaster group established a connection between mitochondrial complex 1 function and radiation-induced UVA biophoton emission from directly irradiated cells. This ultraweak ultraviolet emission proved both necessary and sufficient to produce bystander effects in unirradiated cells held in separate flasks with no medium contact. In parallel, other researchers showed that irradiated cells release exosomes containing miRNAs and even mitochondrial DNA that can communicate information to bystander cells. Reconciling the two hypotheses, Le and colleagues extracted exosomes from cultures that had sat above tritium-irradiated flasks, where beta tracks could not reach them, and demonstrated that the purified exosome fraction induced mitochondrial damage and reproductive cell death in a completely separate set of cells, but only when UVA photons had not been blocked by a yellow cellophane filter.

Perhaps the most provocative claim in the review is that NTEs, long measured using endpoints seen as bad at the level of the individual cell, are actually protective. Bystander signaling can induce adaptive responses, in which signals from irradiated cells prime unirradiated neighbors to resist subsequent genotoxic insults through enhanced DNA repair, altered cell-cycle regulation, antioxidant responses and elimination of damaged cells by apoptosis. The review links this to the phenomenon of low-dose hypersensitivity and induced radioresistance, or HRS/IRR, a dose-response pattern in which cells show a steep response below about 100 mGy followed by a plateau and a shallower curve above roughly 0.5 Gy. Joiner’s group attributed the transition to a threshold dose above which DNA repair becomes inducible, involving PARP and ATR signaling. Collaborative experiments showed that bystander effects could be demonstrated in the HRS region of the dose-response curve but were neutralized when the dose applied in the bystander assay fell in the IRR range, suggesting that RIBE is a low-dose phenomenon that can be counteracted if DNA repair is induced, and that it may account for part of the enigmatic shoulder of the classical survival curve.

Dose and dose rate studies sharpen the picture. Experiments by the authors’ group and Prise’s group determined that NTEs are triggered by very low doses, around 2 to 3 mGy of low-LET radiation, and appear to saturate above 0.5 Gy. A survival curve reconstructed over seven log cycles of dose showed three distinct phases: below 2 mGy no bystander effect, between 2 and 500 mGy no difference between directly irradiated cells and cells receiving irradiated-cell conditioned medium, and above that a clear divergence where directly irradiated cells followed the classic dose response while medium-transfer cells showed no further increase in reproductive death. The calcium spike that Lyng identified as the first sign of bystander signaling was detected only when conditioned medium came from cells receiving 2 mGy or more, indicating a mechanistic threshold. Radiation quality adds further nuance: alpha particles, X-rays and gamma rays all produce bystander effects and genomic instability, but the evidence suggests that pure neutrons, when the gamma contamination is shielded out, do not produce NTE at low doses, a conclusion supported by zebrafish experiments in which robust gamma bystander signaling occurred but neutron exposure produced no effect.

Critics once dismissed NTEs as artifacts of cell culture, but the review assembles ample in vivo evidence. Cross-sex bone marrow transplant studies in mice demonstrated transmissible chromosomal instability in regenerating marrow. Abscopal effects in lung tissue after radiotherapy showed in vivo bystander responses, with the immune system implicated by Demaria and others. Bystander effects were found in serum from Chernobyl-affected populations as long as 20 years after the reactor explosion, and multigenerational genomic instability was documented in bank voles in the Belorussian Polessky reserve. Russian researchers showed that irradiated mice produce volatile signals causing chromosomal damage in unirradiated littermates, and the McMaster group extended inter-animal signaling to fish, earthworms, crickets and mice. Proteomic analysis of bystander fish revealed a protective proteome enriched in antioxidant and DNA repair proteins, which the directly irradiated fish conspicuously lacked, reinforcing the view that NTE signaling functions as an early-warning system coordinating population-level responses.

The implications ripple outward in several directions. For radiotherapy, especially new modalities such as FLASH protocols using ultra-high dose rates, out-of-field and abscopal effects raise questions about how bystander signaling plays out during treatment planning, and whether signals from the tumor ecosystem, including fibroblasts, immune cells and endothelial support vessels, could be exploited as biomarkers or therapeutic targets based on mitochondrial metabolism, the apoptotic cascade or serotonin receptors. For radiation protection, the review argues that NTEs are relevant to low-dose and chronic exposures because they involve signaling between and within populations of species in ecosystems, coordinating adaptation and evolution, concepts such as resilience, adaptation and historic dose. In the human protection field, however, BEIR and UNSCEAR reports merely suggest that no conclusions can be drawn about the relevance of NTE at this time. The authors conclude that imaging and therapy would both benefit from greater mechanistic understanding of NTE, and that these communication mechanisms are likely to be highly relevant to population responses to low-dose radiation at the level of cell, tissue and organism signaling.

Subject of Research: Non-targeted effects of radiation and DNA damage signaling

Article Title: Non-targeted effects and DNA: vulnerabilities at the interface

Article References: Mothersill, C., Rusin, A., & Seymour, C. (2026). Non-targeted effects and DNA: vulnerabilities at the interface. Frontiers in Oncology, 16, Article 1952660. https://doi.org/10.3389/fonc.2026.1952660

Image Credits: AI Generated

DOI: 10.3389/fonc.2026.1952660

Keywords: radiobiology, bystander effect, DNA repair, non-targeted effects, genomic instability, radiotherapy, radiation protection, mitochondria, exosomes, adaptive response, Non-targeted, effects

The review, led by Ruyue Wang and colleagues at Shanghai Mengchao Cancer Hospital and Shanghai University, centers on the pairing of plant-derived natural products, or PDNPs, with plant-derived extracellular vesicles, known as PDEVs. These vesicles are nanoscale particles wrapped in lipid bilayers, released by plant cells through several distinct biological routes. Far from being inert packaging, they carry a dense cargo of proteins, lipids, nucleic acids, and secondary metabolites that mirror the biochemistry of their parent plant. The authors contend that PDEVs act on two fronts simultaneously: as delivery vehicles that rescue poorly behaved plant drugs, and as intrinsic anticancer agents in their own right.

Understanding how these vesicles are made is central to exploiting them. According to their biogenesis, PDEVs fall into several subtypes, including exosomes of roughly 50 to 150 nanometers, microvesicles spanning 100 to 1,000 nanometers, migrasomes that can reach 3,000 nanometers, and apoptotic bodies larger than a micrometer. The dominant production route mirrors the endosomal pathway seen in animal cells: the cell membrane folds inward to form early endosomes, which mature into multivesicular bodies that either fuse with lysosomes for degradation or release their internal vesicles into the extracellular space. Plants add two unusual twists—a vacuole-mediated route that produces ectosomes, and a plant-specific organelle called EXPO, whose double membrane resembles an autophagosome and which releases single-membrane vesicles directly into the cell wall.

Harvesting these vesicles poses a challenge unique to plants: the cell wall. Researchers must first extract the apoplastic fluid that bathes the cell exterior, then purify vesicles from that complex mixture. Milling and juicing are fast and yield high volumes but drag in cellular debris; vacuum infiltration preserves vesicle integrity but suffers from low yield; enzymatic digestion of the wall delivers high purity at the cost of added enzyme contaminants. Downstream, ultracentrifugation remains the workhorse, but newer approaches—size exclusion chromatography, tangential flow filtration, immunoaffinity capture using the tetraspanin TET8 marker, and even charge-based methods such as electrophoresis-dialysis—are reshaping the field. No single technique yet maximizes yield, purity, and functional integrity at once, and the review stresses that combination strategies will likely define the standard going forward.

Once isolated, PDEVs tackle the pharmacokinetic failures of plant drugs head-on. Hydrophobic compounds such as curcumin, resveratrol, and quercetin typically dissolve at only microgram-per-milliliter levels in water, making therapeutically relevant blood concentrations nearly impossible to achieve. The amphipathic lipid bilayer of PDEVs solves this by embedding lipophilic molecules within the membrane while passively encapsulating water-soluble cargo in the aqueous core. Ginger-derived vesicles, for instance, have demonstrated longer circulation half-lives and lower immunogenicity than synthetic nanocarriers. Loading efficiency can be striking: sonication has achieved loading capacities of up to 94 percent for curcumin in ginger-derived vesicles, far surpassing passive co-incubation or electroporation, though the physical stress can deform vesicles and blunt their native bioactivity—a trade-off the review examines candidly.

Protection from degradation is equally critical. Orally administered plant compounds are typically destroyed by gastric acid and digestive enzymes before they reach the bloodstream, while intravenously injected molecules are rapidly cleared by the liver and reticuloendothelial system. The intact phospholipid bilayer of PDEVs acts as a physical shield: ginger-derived exosome-like nanoparticles have been shown to survive simulated gastric and intestinal fluids, delivering their payload intact to the colon. Ginseng-derived nanovesicles, meanwhile, persist in circulation for more than 48 hours after injection, a half-life that dramatically outperforms free drug. Some vesicles even display inherent targeting: mulberry-derived vesicles carry the lipid MGDG, which binds the ASGPR receptor on hepatocellular carcinoma cells, steering the payload selectively toward liver tumors.

Beyond delivery, PDEVs wage their own war on cancer. Bitter melon-derived vesicles overcame chemoresistance in oral squamous cell carcinoma by triggering reactive oxygen species accumulation and mitochondrial dysfunction. Centella asiatica-derived vesicles selectively induced ROS in HepG2 liver cancer cells while sparing normal hepatocytes. Grapefruit-derived vesicles co-inhibited the PI3K/AKT and MAPK/ERK signaling axes in melanoma cells, and garlic-derived vesicles cut Bcl-2 expression by roughly 60 to 65 percent while tripling p53 levels in lung and kidney cancer lines. Lemon-derived vesicles activate the TRAIL death-receptor pathway, a mechanism validated in chronic myeloid leukemia xenografts where pro-angiogenic factors such as VEGF-A, IL-6, and IL-8 also declined. The review notes, however, that context matters: citrus-derived vesicles that kill fibrosarcoma cells leave breast cancer MCF-7 cells untouched, and some vesicles even stimulate proliferation in healthy fibroblasts—a reminder that tumor selectivity is far from universal.

PDEVs also reshape the tumor microenvironment itself. Ginseng-derived vesicles reprogram pro-tumor M2 macrophages toward an anti-tumor M1 phenotype, restore exhausted T cell function, and suppress regulatory T cells through the arginine metabolic pathway. Artemisia annua-derived vesicles activate the cGAS-STING innate immune pathway, converting tumor-associated macrophages into a pro-inflammatory state that inhibits tumor growth. When combined with immunomodulatory plant compounds, the authors argue, these effects could be potentiated into a genuinely synergistic immunotherapy platform—something no synthetic nanoparticle can replicate, because the vesicle itself is pharmacologically active.

Early clinical signals are cautiously encouraging. Only five registered clinical trials involving PDEVs exist to date, but one phase I/II study (NCT01294072) demonstrated that plant-vesicle-mediated delivery increased curcumin accumulation in colon tumor tissue relative to normal mucosa, with an acceptable safety profile. In preclinical mouse models of colon and breast cancer, vesicle-encapsulated curcumin showed markedly improved bioavailability and tumor growth inhibition compared with free drug. Orange-derived vesicles boosted curcumin bioavailability five- to six-fold, while curcumin in turn enhanced the vesicles’ own antioxidant capacity—a bidirectional interaction that hints at deeper cooperative chemistry. Paclitaxel, whose current formulations require Cremophor EL and ethanol solvents that trigger severe allergic reactions, could likewise be reformulated in vesicles to enable oral administration and eliminate excipient toxicity.

Significant obstacles remain before this vision reaches the clinic. The review identifies three core challenges: the absence of standardized isolation and characterization protocols, an incomplete mechanistic understanding of how PDNPs and PDEVs synergize at the molecular level, and a striking scarcity of long-term safety data. More than 80 percent of systemically administered plant nanovesicles accumulate in the liver and spleen, with less than 5 percent reaching intended target tissues, raising legitimate concerns about off-target hepatotoxicity and chronic immune stimulation. Batch-to-batch variability driven by plant cultivar, harvest season, and growth conditions further complicates reproducibility. The authors advocate a toxicology-first framework modeled on synthetic nanomedicine standards, alongside a Quality by Design roadmap spanning raw material standardization under GACP guidelines, scalable manufacturing through tangential flow filtration coupled with size exclusion chromatography, and a robust Chemistry, Manufacturing, and Controls package. If those pillars can be built in parallel, the review concludes, plant vesicles and plant drugs may finally fulfill their combined promise—moving from bench curiosity to bedside reality.

Subject of Research: Synergistic use of plant-derived natural products and plant-derived extracellular vesicles in cancer therapy

Article Title: Application of natural products combined with plant-derived extracellular vesicles in cancer therapy

Article References: Wang, R., Ren, M., Xu, Y., Sun, Y., & Xu, Z. (2026). Application of natural products combined with plant-derived extracellular vesicles in cancer therapy. Experimental Biology and Medicine, 251, Article 11329. https://doi.org/10.3389/ebm.2026.11329

Image Credits: AI Generated

DOI: 10.3389/ebm.2026.11329

Keywords: plant-derived extracellular vesicles, plant-derived natural products, cancer therapy, nanomedicine, drug delivery, curcumin, paclitaxel, tumor microenvironment, exosomes, biocompatibility, immunomodulation, clinical translation

The central problem is that spinal cord injury is not a single event but a cascading catastrophe. The initial mechanical trauma triggers a wave of secondary damage: runaway inflammation, oxidative stress, programmed cell death, excitotoxicity from excessive neurotransmitter signaling, formation of a glial scar that walls off regeneration, and a hostile extracellular environment that blocks axons from regrowing. Each of these processes has become a therapeutic target in its own right, yet traditional drugs struggle to reach the injured tissue at all. The blood-spinal cord barrier, a tight cellular gatekeeper that normally protects neural tissue, also excludes most systemically administered compounds. Drugs that do get through are often cleared rapidly, suffer from short half-lives, and spread into healthy organs where they cause toxic side effects. The result has been a long string of disappointing clinical trials.

Nanocarriers promise to change that calculus by acting as programmable couriers. The review systematically compares the major delivery platforms developed over the past ten years, including liposomes, polymeric nanoparticles, micelles, inorganic nanomaterials, nanozymes, exosomes, biomimetic carriers, nanohydrogels, and composite scaffolds. Each platform occupies a distinct niche. Liposomes, spherical vesicles built from lipid bilayers, can encapsulate both water-soluble and fat-soluble drugs and shield them from premature degradation. Polymeric nanoparticles offer tunable release kinetics, allowing a therapeutic payload to be dispensed over days or weeks rather than in a single burst. Micelles, self-assembled from amphiphilic molecules, excel at solubilizing hydrophobic drugs that would otherwise be unusable. Inorganic nanomaterials bring unique physical properties, such as magnetic guidance or imaging capability, that enable simultaneous diagnosis and treatment.

Two platforms stand out in the review for their preclinical promise: biomimetic carriers and multifunctional nanozymes. Biomimetic carriers take inspiration from nature by cloaking synthetic nanoparticles in cell-derived membranes, such as those from platelets, macrophages, or stem cells. This camouflage exploits the body’s own trafficking signals, allowing the particles to cross biological barriers, evade immune clearance, and home in on inflamed tissue with far greater precision than bare synthetic particles. In the context of spinal cord injury, where the injury microenvironment is saturated with activated immune cells, such biomimetic targeting can concentrate drugs exactly where secondary damage is unfolding. Nanozymes, meanwhile, are engineered nanomaterials that mimic the catalytic activity of natural enzymes. Multifunctional nanozymes can scavenge the reactive oxygen species that drive oxidative stress while simultaneously delivering neuroprotective drugs, effectively combining a therapeutic agent and a delivery vehicle in a single construct.

The review organizes therapeutic effects around seven major mechanisms, providing a framework that researchers can use to match carrier design to pathological need. The first is inhibition of inflammation, particularly through the regulation of macrophage and microglia polarization. After injury, these immune cells can adopt pro-inflammatory states that amplify tissue destruction or anti-inflammatory states that promote repair. Nanocarriers carrying polarizing agents can push this balance toward recovery. The second mechanism is antagonism of oxidative stress, where antioxidant payloads and nanozymes neutralize the free radicals that damage neurons and oligodendrocytes in the hours and days following trauma.

The third and fourth mechanisms involve regulation of programmed cell death and neuroprotection, and the promotion of axonal regeneration alongside myelin repair. Apoptosis and related forms of controlled cell death claim many neurons that survive the initial impact, so nanocarriers that deliver anti-apoptotic agents directly to endangered cells can preserve functional circuitry. Once cell survival is secured, the challenge shifts to rebuilding connections. Axons must regrow through damaged tissue, and the myelin sheaths that insulate them must be restored for signals to travel efficiently. Nanocarriers have been used to deliver growth-promoting factors and inhibitors of myelin-associated repulsive molecules, creating a permissive environment for regeneration.

The remaining mechanisms address the structural aftermath of injury. Glial scar and extracellular matrix remodeling target the dense meshwork of proteins and glial processes that physically blocks regenerating axons; nanotherapies can soften or reorganize this barrier rather than simply trying to push axons through it. Finally, vascular repair and blood-spinal cord barrier reconstruction recognize that recovery of the injury site’s blood supply and the restoration of barrier integrity are prerequisites for lasting functional improvement. Nanocarriers delivering angiogenic factors or barrier-stabilizing compounds address this vascular dimension, which earlier therapeutic strategies often neglected.

Beyond soluble drug delivery, the review highlights biomaterials that provide physical support to the injured cord. Nanohydrogels and composite scaffolds can be injected or implanted into the lesion cavity, where they serve double duty as drug depots and as three-dimensional substrates that guide growing axons. These materials can be engineered to degrade at controlled rates, releasing their payloads in sync with the temporal phases of secondary injury, from the acute inflammatory storm to the chronic scarring stage. This stage-matched delivery is a recurring theme in the review’s analytical framework: the authors argue that rational nanomedicine design should integrate carrier characteristics with the specific pathological mechanisms dominant at each phase of injury, rather than treating spinal cord injury as a uniform target.

Despite the enthusiasm, the review is candid about the bottlenecks standing between laboratory success and clinical reality. Long-term safety validation remains insufficient for most platforms, a serious concern for materials that may persist in neural tissue. Targeting efficiency is often low, meaning that only a fraction of an administered dose reaches the injury site. Significant discrepancies between animal models and human clinical pathology complicate the interpretation of preclinical results, since rodent contusion injuries do not fully recapitulate the heterogeneity of human trauma. Scaling up nanoparticle preparation from bench-top synthesis to reproducible, pharmaceutical-grade manufacturing poses its own engineering and regulatory challenges. These hurdles explain why, despite promising preclinical data, no nanocarrier therapy for spinal cord injury has yet completed successful clinical translation.

Looking forward, the authors identify several directions that could accelerate progress. Microenvironment-responsive smart delivery systems, which release their payloads only when triggered by the acidity, enzyme activity, or oxidative conditions characteristic of injured tissue, could dramatically improve specificity and reduce side effects. The integration of nanotechnology with stem cell therapy and neuromodulation strategies could combine regenerative cell sources with precisely timed molecular support and electrical stimulation. Perhaps most importantly, the establishment of standardized evaluation systems across laboratories would make it possible to compare platforms fairly and build the robust safety and efficacy datasets that regulators require. If those pieces come together, the mechanism-driven framework laid out in this review could serve as the blueprint for turning a decade of nanocarrier innovation into the first effective treatments for a condition that medicine has long considered untreatable.

Subject of Research: Nanocarrier-based targeted drug delivery for spinal cord injury treatment

Article Title: Smart nanocarriers and biomaterials for targeted drug delivery in spinal cord injury: molecular mechanisms and translational perspectives

Article References: Han, W., Qi, P., Li, J., Min, L., Li, H., & Yin, H. (2026). Smart nanocarriers and biomaterials for targeted drug delivery in spinal cord injury: molecular mechanisms and translational perspectives. Frontiers in Bioengineering and Biotechnology, 14, Article 1973263. https://doi.org/10.3389/fbioe.2026.1973263

Image Credits: AI Generated

DOI: 10.3389/fbioe.2026.1973263

Keywords: spinal cord injury, nanocarriers, drug delivery, biomimetic carriers, nanozymes, blood-spinal cord barrier, glial scar, axonal regeneration, liposomes, exosomes, nanohydrogels, neuroprotection