Utilizing engineered extracellular vesicles as delivery vectors in the management of ischemic stroke:a special outlook on mitochondrial delivery

Ischemic stroke is a secondary cause of mortality worldwide,imposing considerable medical and economic burdens on society.Extracellular vesicles,serving as natural nanocarriers for drug delivery,exhibit excellent biocompatibility in vivo and have significant advantages in the management of ischemic stroke.However,the uncertain distribution and rapid clearance of extracellular vesicles impede their delivery efficiency.By utilizing membrane decoration or by encapsulating therapeutic cargo within extracellular vesicles,their delivery efficacy may be greatly improved.Furthermore,previous studies have indicated that microvesicles,a subset of large-sized extracellular vesicles,can transport mitochondria to neighboring cells,thereby aiding in the restoration of mitochondrial function post-ischemic stroke.Small extracellular vesicles have also demonstrated the capability to transfer mitochondrial components,such as proteins or deoxyribonucleic acid,or their sub-components,for extracellular vesicle-based ischemic stroke therapy.In this review,we undertake a comparative analysis of the isolation techniques employed for extracellular vesicles and present an overview of the current dominant extracellular vesicle modification methodologies.Given the complex facets of treating ischemic stroke,we also delineate various extracellular vesicle modification approaches which are suited to different facets of the treatment process.Moreover,given the burgeoning interest in mitochondrial delivery,we delved into the feasibility and existing research findings on the transportation of mitochondrial fractions or intact mitochondria through small extracellular vesicles and microvesicles to offer a fresh perspective on ischemic stroke therapy.

Small extracellular vesicles derived from cerebral endothelial cells with elevated microRNA 27a promote ischemic stroke recovery

Axonal remodeling is a critical aspect of ischemic brain repair processes and contributes to spontaneous functional recovery.Our previous in vitro study demonstrated that exosomes/small extracellular vesicles(sEVs)isolated from cerebral endothelial cells(CEC-sEVs)of ischemic brain promote axonal growth of embryonic cortical neurons and that microRNA 27a(miR-27a)is an elevated miRNA in ischemic CEC-sEVs.In the present study,we investigated whether normal CEC-sEVs engineered to enrich their levels of miR-27a(27a-sEVs)further enhance axonal growth and improve neurological outcomes after ischemic stroke when compared with treatment with non-engineered CEC-sEVs.27a-sEVs were isolated from the conditioned medium of healthy mouse CECs transfected with a lentiviral miR-27a expression vector.Small EVs isolated from CECs transfected with a scramble vector(Scra-sEVs)were used as a control.Adult male mice were subjected to permanent middle cerebral artery occlusion and then were randomly treated with 27a-sEVs or Scra-sEVs.An array of behavior assays was used to measure neurological function.Compared with treatment of ischemic stroke with Scra-sEVs,treatment with 27a-sEVs significantly augmented axons and spines in the peri-infarct zone and in the corticospinal tract of the spinal grey matter of the denervated side,and significantly improved neurological outcomes.In vitro studies demonstrated that CEC-sEVs carrying reduced miR-27a abolished 27a-sEV-augmented axonal growth.Ultrastructural analysis revealed that 27a-sEVs systemically administered preferentially localized to the pre-synaptic active zone,while quantitative reverse transcription-polymerase chain reaction and Western Blot analysis showed elevated miR-27a,and reduced axonal inhibitory proteins Semaphorin 6A and Ras Homolog Family Member A in the peri-infarct zone.Blockage of the Clathrin-dependent endocytosis pathway substantially reduced neuronal internalization of 27a-sEVs.Our data provide evidence that 27a-sEVs have a therapeutic effect on stroke recovery by promoting axonal remodeling and improving neurological outcomes.Our findings also suggest that suppression of axonal inhibitory proteins such as Semaphorin 6A may contribute to the beneficial effect of 27a-sEVs on axonal remodeling.

Small extracellular vesicles derived from human induced pluripotent stem cell-differentiated neural progenitor cells mitigate retinal ganglion cell degeneration in a mouse model of optic nerve injury

Several studies have found that transplantation of neural progenitor cells(NPCs)promotes the survival of injured neurons.However,a poor integration rate and high risk of tumorigenicity after cell transplantation limits their clinical application.Small extracellular vesicles(sEVs)contain bioactive molecules for neuronal protection and regeneration.Previous studies have shown that stem/progenitor cell-derived sEVs can promote neuronal survival and recovery of neurological function in neurodegenerative eye diseases and other eye diseases.In this study,we intravitreally transplanted sEVs derived from human induced pluripotent stem cells(hiPSCs)and hiPSCs-differentiated NPCs(hiPSC-NPC)in a mouse model of optic nerve crush.Our results show that these intravitreally injected sEVs were ingested by retinal cells,especially those localized in the ganglion cell layer.Treatment with hiPSC-NPC-derived sEVs mitigated optic nerve crush-induced retinal ganglion cell degeneration,and regulated the retinal microenvironment by inhibiting excessive activation of microglia.Component analysis further revealed that hiPSC-NPC derived sEVs transported neuroprotective and anti-inflammatory miRNA cargos to target cells,which had protective effects on RGCs after optic nerve injury.These findings suggest that sEVs derived from hiPSC-NPC are a promising cell-free therapeutic strategy for optic neuropathy.

Targeting capabilities of engineered extracellular vesicles for the treatment of neurological diseases

Recent advances in research on extracellular vesicles have significantly enhanced their potential as therapeutic agents for neurological diseases.Owing to their therapeutic properties and ability to cross the blood–brain barrier,extracellular vesicles are recognized as promising drug delivery vehicles for various neurological conditions,including ischemic stroke,traumatic brain injury,neurodegenerative diseases,glioma,and psychosis.However,the clinical application of natural extracellular vesicles is hindered by their limited targeting ability and short clearance from the body.To address these limitations,multiple engineering strategies have been developed to enhance the targeting capabilities of extracellular vesicles,thereby enabling the delivery of therapeutic contents to specific tissues or cells.Therefore,this review aims to highlight the latest advancements in natural and targeting-engineered extracellular vesicles,exploring their applications in treating traumatic brain injury,ischemic stroke,Parkinson's disease,Alzheimer's disease,amyotrophic lateral sclerosis,glioma,and psychosis.Additionally,we summarized recent clinical trials involving extracellular vesicles and discussed the challenges and future prospects of using targeting-engineered extracellular vesicles for drug delivery in treating neurological diseases.This review offers new insights for developing highly targeted therapies in this field.

The emerging role of mesenchymal stem cell-derived extracellular vesicles to ameliorate hippocampal NLRP3 inflammation induced by binge-like ethanol treatment in adolescence

Our previous studies have reported that activation of the NLRP3(NOD-,LRR-and pyrin domain-containing protein 3)-inflammasome complex in ethanol-treated astrocytes and chronic alcohol-fed mice could be associated with neuroinflammation and brain damage.Mesenchymal stem cell-derived extracellular vesicles(MSC-EVs)have been shown to restore the neuroinflammatory response,along with myelin and synaptic structural alterations in the prefrontal cortex,and alleviate cognitive and memory dysfunctions induced by binge-like ethanol treatment in adolescent mice.Considering the therapeutic role of the molecules contained in mesenchymal stem cell-derived extracellular vesicles,the present study analyzed whether the administration of mesenchymal stem cell-derived extracellular vesicles isolated from adipose tissue,which inhibited the activation of the NLRP3 inflammasome,was capable of reducing hippocampal neuroinflammation in adolescent mice treated with binge drinking.We demonstrated that the administration of mesenchymal stem cell-derived extracellular vesicles ameliorated the activation of the hippocampal NLRP3 inflammasome complex and other NLRs inflammasomes(e.g.,pyrin domain-containing 1,caspase recruitment domain-containing 4,and absent in melanoma 2,as well as the alterations in inflammatory genes(interleukin-1β,interleukin-18,inducible nitric oxide synthase,nuclear factor-kappa B,monocyte chemoattractant protein-1,and C–X3–C motif chemokine ligand 1)and miRNAs(miR-21a-5p,miR-146a-5p,and miR-141-5p)induced by binge-like ethanol treatment in adolescent mice.Bioinformatic analysis further revealed the involvement of miR-21a-5p and miR-146a-5p with inflammatory target genes and NOD-like receptor signaling pathways.Taken together,these findings provide novel evidence of the therapeutic potential of MSC-derived EVs to ameliorate the hippocampal neuroinflammatory response associated with NLRP3 inflammasome activation induced by binge drinking in adolescence.

Human neural stem cell-derived extracellular vesicles protect against ischemic stroke by activating the PI3K/AKT/mTOR pathway

Human neural stem cell-derived extracellular vesicles exhibit analogous functions to their parental cells,and can thus be used as substitutes for stem cells in stem cell therapy,thereby mitigating the risks of stem cell therapy and advancing the frontiers of stem cell-derived treatments.This lays a foundation for the development of potentially potent new treatment modalities for ischemic stroke.However,the precise mechanisms underlying the efficacy and safety of human neural stem cell-derived extracellular vesicles remain unclear,presenting challenges for clinical translation.To promote the translation of therapy based on human neural stem cell-derived extracellular vesicles from the bench to the bedside,we conducted a comprehensive preclinical study to evaluate the efficacy and safety of human neural stem cell-derived extracellular vesicles in the treatment of ischemic stroke.We found that administration of human neural stem cell-derived extracellular vesicles to an ischemic stroke rat model reduced the volume of cerebral infarction and promoted functional recovery by alleviating neuronal apoptosis.The human neural stem cell-derived extracellular vesicles reduced neuronal apoptosis by enhancing phosphorylation of phosphoinositide 3-kinase,mammalian target of rapamycin,and protein kinase B,and these effects were reversed by treatment with a phosphoinositide 3-kinase inhibitor.These findings suggest that human neural stem cell-derived extracellular vesicles play a neuroprotective role in ischemic stroke through activation of phosphoinositide 3-kinase/protein kinase B/mammalian target of rapamycin signaling pathway.Finally,we showed that human neural stem cell-derived extracellular vesicles have a good in vivo safety profile.Therefore,human neural stem cell-derived extracellular vesicles are a promising potential agent for the treatment of ischemic stroke.

Methods,Mechanisms,and Application Prospects for Enhancing Extracellular Vesicle Uptake

Extracellular vesicles(EVs)are considered to be a new generation of bioinspired nanoscale drug delivery systems due to their low immunogenicity,natural functionality,and excellent biocompatibility.However,limitations such as low uptake efficiency,insufficient production,and inhomogeneous performance undermine their potential.To address these issues,numerous researchers have put forward various methods and applications for enhancing EV uptake in recent decades.In this review,we introduce various methods for the cellular uptake of EVs and summarize recent advances on the methods and mechanisms for enhancing EV uptake.In addition,we provide further understanding regarding enhancing EV uptake and put forward prospects and challenges for the development of EV-based therapy in the future.

Extracellular vesicles for delivering therapeutic agents in ischemia/reperfusion injury

Ischemia/reperfusion(I/R)injury ismarked by the restriction and subsequent restoration of blood supply to an organ.This process can exacerbate the initial tissue damage,leading to further disorders,disability,and even death.Extracellular vesicles(EVs)are crucial in cell communication by releasing cargo that regulates the physiological state of recipient cells.The development of EVs presents a novel avenue for delivering therapeutic agents in I/R therapy.The therapeutic potential of EVs derived from stem cells,endothelial cells,and plasma in I/R injury has been actively investigated.Therefore,this review aims to provide an overview of the pathological process of I/R injury and the biophysical properties of EVs.We noted that EVs serve as nontoxic,flexible,and multifunctional carriers for delivering therapeutic agents capable of intervening in I/R injury progression.The therapeutic efficacy of EVs can be enhanced through various engineering strategies.Improving the tropism of EVs via surface modification and modulating their contents via preconditioning are widely investigated in preclinical studies.Finally,we summarize the challenges in the production and delivery of EV-based therapy in I/R injury and discuss how it can advance.This review will encourage further exploration in developing efficient EV-based delivery systems for I/R treatment.

Pathological and therapeutic effects of extracellular vesicles in neurological and neurodegenerative diseases

Extracellular vesicles are released by all cell types and contain proteins,microRNAs,mRNAs,and other bioactive molecules.Extracellular vesicles play an important role in intercellular communication and in the modulation of the immune system and neuroinflammation.The cargo of extra cellular vesicles(e.g.,proteins and microRNAs)is altered in pathological situations.Extracellular vesicles contribute to the pathogenesis of many pathologies associated with sustained inflammation and neuroinflammation,including cance r,diabetes,hype rammonemia and hepatic encephalopathy,and other neurological and neurodegenerative diseases.Extracellular vesicles may cross the blood-brain barrier and transfer pathological signals from the periphery to the brain.This contributes to inducing neuroinflammation and cognitive and motor impairment in hyperammonemia and hepatic encephalopathy and in neurodegenerative diseases.The mechanisms involved are beginning to be unde rstood.For example,increased tumor necrosis factor a in extracellular vesicles from plasma of hype rammonemic rats induces neuroinflammation and motor impairment when injected into normal rats.Identifying the mechanisms by which extracellular vesicles contribute to the pathogenesis of these diseases will help to develop new treatments and diagnostic tools for their easy and early detection.In contrast,extra cellular vesicles from mesenchymal stem cells have therapeutic utility in many of the above pathologies,by reducing inflammation and neuroinflammation and improving cognitive and motor function.These extra cellular vesicles recapitulate the beneficial effects of mesenchymal stem cells and have advantages as therapeutic tools:they are less immunoge nic,may not diffe rentiate to malignant cells,cross the blood-brain barrier,and may reach more easily target organs.Extracellular vesicles from mesenchymal stem cells have beneficial effects in models of ischemic brain injury,Alzheimer's and Parkinson's diseases,hyperammonemia,and hepatic encephalopathy.Extracellular vesicles from mesenchymal stem cells modulate the immune system,promoting the shift from a pro-inflammato ry to an anti-inflammatory state.For example,extracellular vesicles from mesenchymal stem cells modulate the Th17/Treg balance,promoting the anti-inflammatory Treg.Extracellular vesicles from mesenchymal stem cells may also act directly in the brain to modulate microglia activation,promoting a shift from a pro-inflammatory to an anti-inflammatory state.This reduces neuroinflammation and improves cognitive and motor function.Two main components of extracellular vesicles from mesenchymal stem cells which contribute to these beneficial effects are transforming growth factor-βand miR-124.Identifying the mechanisms by which extracellular vesicles from mesenchymal stem cells induce the beneficial effects and the main molecules(e.g.,proteins and mRNAs)involved may help to improve their therapeutic utility.The aims of this review are to summarize the knowledge of the pathological effects of extracellular vesicles in different pathologies,the therapeutic potential of extra cellular vesicles from mesenchymal stem cells to recover cognitive and motor function and the molecular mechanisms for these beneficial effects on neurological function.

Mesenchymal stem cell-derived extracellular vesicles as a cell-free therapy for traumatic brain injury via neuroprotection and neurorestoration

Traumatic brain injury is a serious and complex neurological condition that affects millions of people worldwide.Despite significant advancements in the field of medicine,effective treatments for traumatic brain injury remain limited.Recently,extracellular vesicles released from mesenchymal stem/stromal cells have emerged as a promising novel therapy for traumatic brain injury.Extracellular vesicles are small membrane-bound vesicles that are naturally released by cells,including those in the brain,and can be engineered to contain therapeutic cargo,such as anti-inflammatory molecules,growth factors,and microRNAs.When administered intravenously,extra cellular vesicles can cross the blood-brain barrier and deliver their cargos to the site of injury,where they can be taken up by recipient cells and modulate the inflammatory response,promote neuroregeneration,and improve functional outcomes.In preclinical studies,extracellular vesicle-based therapies have shown promising results in promoting recove ry after traumatic brain injury,including reducing neuronal damage,improving cognitive function,and enhancing motor recovery.While further research is needed to establish the safety and efficacy of extra cellular vesicle-based therapies in humans,extra cellular vesicles represent a promising novel approach for the treatment of traumatic brain injury.In this review,we summarize mesenchymal ste m/stromal cell-de rived extracellular vesicles as a cell-free therapy for traumatic brain injury via neuroprotection and neurorestoration and brainderived extracellular vesicles as potential biofluid biomarkers in small and large animal models of traumatic brain injury.

Extracellular vesicles in anti-tumor drug resistance: Mechanisms and therapeutic prospects

Drug resistance presents a significant challenge to achieving positive clinical outcomes in anti-tumor therapy.Prior research has illuminated reasons behind drug resistance,including increased drug efflux,alterations in drug targets,and abnormal activation of oncogenic pathways.However,there's a need for deeper investigation into the impact of drug-resistant cells on parental tumor cells and intricate crosstalk between tumor cells and the malignant tumor microenvironment(TME).Recent studies on extracellular vesicles(EVs)have provided valuable insights.EVs are membrane-bound particles secreted by all cells,mediating cell-to-cell communication.They contain functional cargoes like DNA,RNA,lipids,proteins,and metabolites from mother cells,delivered to other cells.Notably,EVs are increasingly recognized as regulators in the resistance to anti-cancer drugs.This review aims to summarize the mechanisms of EV-mediated anti-tumor drug resistance,covering therapeutic approaches like chemo-therapy,targeted therapy,immunotherapy and even radiotherapy.Detecting Ev-based biomarkers to predict drug resistance assists in bypassing anti-tumor drug resistance.Additionally,targeted inhibition of EV biogenesis and secretion emerges as a promising approach to counter drug resistance.We highlight the importance of conducting in-depth mechanistic research on EVs,their cargoes,and functional ap-proaches specifically focusing on EV subpopulations.These efforts will significantly advance the devel-opment of strategies to overcome drug resistance in anti-tumor therapy.

Advances in extracellular vesicle-based combination therapies for spinal cord injury

Spinal cord injury is a severe insult to the central nervous system that causes persisting neurological deficits.The currently available treatments involve surgical,medical,and rehabilitative strategies.However,none of these techniques can markedly reverse neurological deficits.Recently,extracellular vesicles from various cell sources have been applied to different models of spinal cord injury,thereby generating new cell-free therapies for the treatment of spinal cord injury.However,the use of extracellular vesicles alone is still associated with some notable shortcomings,such as their uncertainty in targeting damaged spinal cord tissues and inability to provide structural support to damaged axons.Therefore,this paper reviews the latest combined strategies for the use of extracellular vesicle-based technology for spinal cord injury,including the combination of extracellular vesicles with nanoparticles,exogenous drugs and/or biological scaffold materials,which facilitate the targeting ability of extracellular vesicles and the combinatorial effects with extracellular vesicles.We also highlight issues relating to the clinical transformation of these extracellular vesicle-based combination strategies for the treatment of spinal cord injury.

Connecting cellular mechanisms and extracellular vesicle cargo in traumatic brain injury

Traumatic brain injury is followed by a cascade of dynamic and complex events occurring at the cellular level. These events include: diffuse axonal injury, neuronal cell death, blood-brain barrier break down, glial activation and neuroinflammation, edema, ischemia, vascular injury, energy failure, and peripheral immune cell infiltration. The timing of these events post injury has been linked to injury severity and functional outcome. Extracellular vesicles are membrane bound secretory vesicles that contain markers and cargo pertaining to their cell of origin and can cross the blood-brain barrier. These qualities make extracellular vesicles intriguing candidates for a liquid biopsy into the pathophysiologic changes occurring at the cellular level post traumatic brain injury. Herein, we review the most commonly reported cargo changes in extracellular vesicles from clinical traumatic brain injury samples. We then use knowledge from animal and in vitro models to help infer what these changes may indicate regrading cellular responses post traumatic brain injury. Future research should prioritize labeling extracellular vesicles with markers for distinct cell types across a range of timepoints post traumatic brain injury.

Mesenchymal stem cell-derived extracellular vesicles in skin wound healing:roles,opportunities and challenges

Skin wounds are characterized by injury to the skin due to trauma,tearing,cuts,or contusions.As such injuries are common to all human groups,they may at times represent a serious socioeconomic burden.Currently,increasing numbers of studies have focused on the role of mesenchymal stem cell(MSC)-derived extracellular vesicles(EVs)in skin wound repair.As a cell-free therapy,MSC-derived EVs have shown significant application potential in the field of wound repair as a more stable and safer option than conventional cell therapy.Treatment based on MSC-derived EVs can significantly promote the repair of damaged substructures,including the regeneration of vessels,nerves,and hair follicles.In addition,MSC-derived EVs can inhibit scar formation by affecting angiogenesis-related and antifibrotic pathways in promoting macrophage polarization,wound angiogenesis,cell proliferation,and cell migration,and by inhibiting excessive extracellular matrix production.Additionally,these structures can serve as a scaffold for components used in wound repair,and they can be developed into bioengineered EVs to support trauma repair.Through the formulation of standardized culture,isolation,purification,and drug delivery strategies,exploration of the detailed mechanism of EVs will allow them to be used as clinical treatments for wound repair.In conclusion,MSCderived EV-based therapies have important application prospects in wound repair.Here we provide a comprehensive overview of their current status,application potential,and associated drawbacks.

Small extracellular vesicles from hypoxia-preconditioned bone marrow mesenchymal stem cells attenuate spinal cord injury via miR-146a-5p-mediated regulation of macrophage polarization

Spinal cord injury is a disabling condition with limited treatment options.Multiple studies have provided evidence suggesting that small extracellular vesicles(SEVs)secreted by bone marrow mesenchymal stem cells(MSCs)help mediate the beneficial effects conferred by MSC transplantation following spinal cord injury.Strikingly,hypoxia-preconditioned bone marrow mesenchymal stem cell-derived SEVs(HSEVs)exhibit increased therapeutic potency.We thus explored the role of HSEVs in macrophage immune regulation after spinal cord injury in rats and their significance in spinal cord repair.SEVs or HSEVs were isolated from bone marrow MSC supernatants by density gradient ultracentrifugation.HSEV administration to rats via tail vein injection after spinal cord injury reduced the lesion area and attenuated spinal cord inflammation.HSEVs regulate macrophage polarization towards the M2 phenotype in vivo and in vitro.Micro RNA sequencing and bioinformatics analyses of SEVs and HSEVs revealed that mi R-146a-5p is a potent mediator of macrophage polarization that targets interleukin-1 receptor-associated kinase 1.Reducing mi R-146a-5p expression in HSEVs partially attenuated macrophage polarization.Our data suggest that HSEVs attenuate spinal cord inflammation and injury in rats by transporting mi R-146a-5p,which alters macrophage polarization.This study provides new insights into the application of HSEVs as a therapeutic tool for spinal cord injury.

tRNA^(Glu)-derived fragments from embryonic extracellular vesicles modulate bovine embryo hatching

Transfer RNA-derived small RNAs(tsRNAs)have been shown to be involved in early embryo development and repression of endogenous retroelements in embryos and stem cells.However,it is unknown whether tsRNAs also regulate embryo hatching.In this study,we mined the sequencing data of a previous experiment in which we demonstrated that the microRNA(miRNA)cargo of preimplantation embryonic extracellular vesicles(EVs)influences embryo development.We thus profiled the tsRNA cargo of EVs secreted by blastocysts and non-blastocysts.The majority of tsRNAs was identified as tRNA halves originating from the 5'ends of tRNAs.Among the 148 differentially expressed tsRNAs,the 19 nt tRNA fragment(tRF)tDR-14:32-Glu-CTC-1 was found to be significantly up-regulated in EVs derived from non-blastocysts.RT-qPCR assays confirmed its significant up-regulation in non-blastocyst embryos and their conditioned medium compared to the blastocyst group(P<0.05).Inhibition of tDR-14:32-Glu-CTC-1 by supplementing antagomirs to the conditioned medium improved embryo hatching(P<0.05).Transcriptomic analysis of embryos treated with tDR-14:32-Glu-CTC-1 antagomirs further showed differential expression of genes that are associated with embryo hatching and implantation.In summary,tDR-14:32-Glu-CTC-1 is up-regulated in non-blastocyst embryos and their secretions,and inhibition of tDR-14:32-Glu-CTC-1 promotes embryo hatching,while influencing embryo implantation-related genes and pathways.These results indicate that embryonic EVs containing specific tRFs may regulate preimplantation embryo development.

Extracellular vesicle-functionalized bioactive scaffolds for bone regeneration

The clinical need for effective bone regeneration in compromised conditions continues to drive demand for innovative solutions.Among emerging strategies,extracellular vesicles(EVs)have shown promise as an acellular approach for bone regeneration.However,their efficacy is hindered by rapid sequestration and clearance when administered via bolus injection.To address this challenge,EV-functionalized scaffolds have recently been proposed as an alternative delivery strategy to enhance EV retention and subsequent healing efficacy.This review aims to consolidate recent advancements in the development of EV-functionalized scaffolds for augmenting bone regeneration.It explores various sources of EVs and different strategies for integrating them into biomaterials.Furthermore,the mechanisms underlying their therapeutic effects in bone regeneration are elucidated.Current limitations in clinical translation and perspectives on the design of more efficient EVs for improved therapeutic efficacy are also presented.Overall,this review can provide inspiration for the development of novel EV-assisted grafts with superior bone regeneration potential.

Cell membrane vesicles derived from hBMSCs and hUVECs enhance bone regeneration

Bone tissue renewal can be enhanced through co-transplantation of bone mesenchymal stem cells(BMSCs)and vascular endothelial cells(ECs).However,there are apparent limitations in stem cell-based therapy which hinder its clinic translation.Hence,we investigated the potential of alternative stem cell substitutes for facilitating bone regeneration.In this study,we successfully prepared cell membrane vesicles(CMVs)from BMSCs and ECs.The results showed that BMSC-derived cell membrane vesicles(BMSC-CMVs)possessed membrane receptors involved in juxtacrine signaling and growth factors derived from their parental cells.EC-derived cell membrane vesicles(EC-CMVs)also contained BMP2 and VEGF derived from their parental cells.BMSC-CMVs enhanced tube formation and migration ability of hUVECs,while EC-CMVs promoted the osteogenic differentiation of hBMSCs in vitro.Using a rat skull defect model,we found that co-transplantation of BMSC-CMVs and EC-CMVs could stimulate angiogenesis and bone formation in vivo.Therefore,our research might provide an innovative and feasible approach for cell-free therapy in bone tissue regeneration.

Membrane vesicles derived from Streptococcus suis serotype 2 induce cell pyroptosis in endothelial cells via the NLRP3/Caspase-1/GSDMD pathway

Streptococcus suis serotype 2(S.suis 2)is a zoonotic pathogen that clinically causes severe swine and human infections(such as meningitis,endocarditis,and septicemia).In order to cause widespread diseases in different organs,S.suis 2 must colonize the host,break the blood barrier,and cause exaggerated inflammation.In the last few years,most studies have focused on a single virulence factor and its influences on the host.Membrane vesicles(MVs)can be actively secreted into the extracellular environment contributing to bacteria-host interactions.Gram-negative bacteria-derived outer membrane vesicles(OMVs)were recently shown to activate host Caspase-11-mediated non-canonical inflammasome pathway via deliverance of OMV-bound lipopolysaccharide(LPS),causing host cell pyroptosis.However,little is known about the effect of the MVs from S.suis 2(Gram-positive bacteria without LPS)on cell pyroptosis.Thus,we investigated the molecular mechanism by which S.suis 2 MVs participate in endothelial cell pyroptosis.In this study,we used proteomics,electron scanning microscopy,fluorescence microscope,Western blotting,and bioassays,to investigate the MVs secreted by S.suis 2.First,we demonstrated that S.suis 2 secreted MVs with an average diameter of 72.04 nm,and 200 proteins in MVs were identified.Then,we showed that MVs were transported to cells via mainly dynamin-dependent endocytosis.The S.suis 2 MVs activated NLRP3/Caspase-1/GSDMD canonical inflammasome signaling pathway,resulting in cell pyroptosis,but it did not activate the Caspase-4/-5 pathway.More importantly,endothelial cells produce large amounts of reactive oxygen species(ROS)and lost their mitochondrial membrane potential under induction by S.suis 2 MVs.The results in this study suggest for the first time that MVs from S.suis 2 were internalized by endothelial cells via mainly dynamin-dependent endocytosis and might promote NLRP3/Caspase-1/GSDMD pathway by mitochondrial damage,which produced mtDNA and ROS under induction,leading to the pyroptosis of endothelial cells.

From mesenchymal stem cells to their extracellular vesicles:Progress and prospects for asthma therapy

Asthma is a widespread public health concern,with an increasing incidence.Despite the implementation of current treatment strategies,asthma control,particularly for severe cases,remains suboptimal.Recent research has revealed the encouraging prospects of extracellular vesicles(EVs)secreted by mesenchymal stem cells(MSCs)as a viable therapeutic option for alleviating asthma symptoms.Therefore,the present review aims to provide an overview of the current progress and the therapeutic mechanisms of using MSC-derived EVs(MSC-EVs)for asthma treatment.Additionally,different administration approaches for EVs and their impacts on biodistribution and the curative outcomes of EVs are summarized.Notably,the potential benefits of nebulized inhalation of MSC-EVs are addressed.Also,the possibilities and challenges of using MSC-EVs for asthma treatment in clinics are highlighted.Overall,this reviewis intended to give newinsight into the utilization of MSC-EVs as a potential biological drug for asthma treatment.