Mesenchymal stem cells use extracellular vesicles to outsource mitophagy and shuttle microRNAs

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 nano-carriers 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.

Idiopathic pulmonary fibrosis microenvironment: Novel mechanisms and research directions

Idiopathic Pulmonary Fibrosis (IPF) is a progressive interstitial lung disease marked by increasing dyspnea and respiratory failure. The underlying mechanisms remain poorly understood, given the complexity of its pathogenesis. This review investigates the microenvironment of IPF to identify novel mechanisms and therapeutic avenues. Studies have revealed that various cell types, including alveolar epithelial cells, fibroblasts, myofibroblasts, and immune cells, are integral to disease progression, engaging in cellular stress responses and inflammatory regulation via signaling pathways such as TGF-β, Wnt, mTOR, and ROS. Non-coding RNAs, particularly miRNAs, are critical in IPF and may serve as diagnostic and prognostic biomarkers. Regarding treatment, mesenchymal stem cells (MSCs) and their extracellular vesicles (EVs) or non-vesicular derivatives offer promise by modulating immune responses, enhancing tissue repair, and inhibiting fibrosis. Additionally, alterations in the lung microbiota are increasingly recognized as a contributing factor to IPF progression, offering fresh insights into potential treatments. Despite the encouraging results of MSC-based therapies, the precise mechanisms and clinical applications remain subjects of ongoing research. This review emphasizes the significance of the IPF microenvironment and highlights the need for further exploration to develop effective therapies that could enhance patient outcomes.

Regulation of synaptic mitochondria by extracellular vesicles and its implications for neuronal metabolism and synaptic plasticity

Mitochondrial metabolism in neurons is necessary for energetically costly processes like synaptic transmission and plasticity. As post-mitotic cells, neurons are therefore faced with the challenge of maintaining healthy functioning mitochondria throughout lifetime. The precise mechanisms of mitochondrial maintenance in neurons, and particularly in morphologically complex dendrites and axons, are not fully understood. Evidence from several biological systems suggests the regulation of cellular metabolism by extracellular vesicles (EVs), secretory lipid-enclosed vesicles that have emerged as important mediators of cell communication. In the nervous system, neuronal and glial EVs were shown to regulate neuronal circuit development and function, at least in part via the transfer of protein and RNA cargo. Interestingly, EVs have been implicated in diseases characterized by altered metabolism, such as cancer and neurodegenerative diseases. Furthermore, nervous system EVs were shown to contain proteins related to metabolic processes, mitochondrial proteins and even intact mitochondria. Here, we present the current knowledge of the mechanisms underlying neuronal mitochondrial maintenance, and highlight recent evidence suggesting the regulation of synaptic mitochondria by neuronal and glial cell EVs. We further discuss the potential implications of EV-mediated regulation of mitochondrial maintenance and function in neuronal circuit development and synaptic plasticity.

Mesenchymal stem cell-derived exosomes: a novel therapeutic frontier in hematological disorders

Mesenchymal stem cells (MSCs) are multipotent stromal cells valued for their immunomodulatory and regenerative properties, positioning them as a cornerstone of regenerative medicine. Their derived exosomes small extracellular vesicles laden with bioactive molecules such as proteins, lipids, and nucleic acids have emerged as critical mediators of MSC therapeutic effects. This review systematically explores the biology of MSC-derived exosomes, detailing their biogenesis, molecular composition, and pivotal roles in hematopoiesis, inflammation, and immune regulation. In hematological disorders, including leukemia, lymphoma, and myelodysplastic syndromes, these exosomes exhibit significant therapeutic potential by modulating the tumor microenvironment, enhancing hematopoietic recovery, and suppressing malignant cell proliferation. Notable findings include their ability to induce cell cycle arrest in leukemia cells via the p53 pathway and to reduce chemoresistance through targeted signaling mechanisms, such as the IRF2/INPP4B axis. However, clinical translation is hindered by several challenges, including the standardization of isolation techniques such as ultracentrifugation which are costly and susceptible to contamination as well as difficulties in optimizing large-scale production and ensuring long-term safety and efficacy. Despite these obstacles, MSC-derived exosomes offer a promising, cell-free therapeutic alternative that minimizes risks such as immune rejection and tumorigenicity associated with whole-cell therapies. Future research must prioritize the refinement of isolation and production protocols, the development of precise delivery strategies, and the execution of comprehensive safety evaluations to unlock their full clinical potential in treating hematological disorders and beyond. This review integrates recent advancements to provide a clearer understanding of their multifaceted contributions and highlights the critical gaps that remain.

Targeting mitochondrial transfer as a promising therapeutic strategy

Despite the primary impression of mitochondria as energy factories, these organelles are increasingly recognized for their multifaceted roles beyond energy production. Intriguingly, mitochondria can transfer between cells, influencing physiological and pathological processes through intercellular trafficking termed 'mitochondrial transfer.' This phenomenon is important in maintaining metabolic homeostasis, enhancing tissue regeneration, exacerbating cancer progression, and facilitating immune modulation, depending on the cell type and microenvironment. Recently, mitochondrial transfer has emerged as a promising therapeutic target for tissue repair and antitumor therapy. Here, we summarize and critically review recent advances in this field. We aim to provide an updated overview of the mechanisms and potential therapeutic avenues associated with mitochondrial transfer in various diseases from the perspective of different donor cells.

Mitochondria-derived vesicles: A promising and potential target for tumour therapy

Mitochondria-derived vesicles (MDVs) participate in early cellular defence mechanisms initiated in response to mitochondrial damage. They maintain mitochondrial quality control (MQC) by clearing damaged mitochondrial components, thereby ensuring the normal functioning of cellular processes. This process is crucial for cell survival and health, as mitochondria are the energy factories of cells, and their damage can cause cellular dysfunction and even death. Recent studies have shown that MDVs not only maintain mitochondrial health but also have a significant impact on tumour progression. MDVs selectively encapsulate and transport damaged mitochondrial proteins under oxidative stress and reduce the adverse effects of mitochondrial damage on cells, which may promote the survival and proliferation of tumour cells. Furthermore, it has been indicated that after cells experience mild stress, the number of MDVs significantly increases within 2-6 h, whereas mitophagy, a process of clearing damaged mitochondria, occurs 12-24 h later. This suggests that MDVs play a critical role in the early stress response of cells. Moreover, MDVs also have a significant role in intercellular communication, specifically in the tumour microenvironment. They can carry and transmit various bioactive molecules, such as proteins, nucleic acids, and lipids, which regulate tumour cell's growth, invasion, and metastasis. This intercellular communication may facilitate tumour spread and metastasis, making MDVs a potential therapeutic target. Advances in MDV research have identified novel biomarkers, clarified regulatory mechanisms, and provided evidence for clinical use. These breakthroughs pave the way for novel MDV-targeted therapies, offering improved treatment alternatives for cancer patients. Further research can identify MDVs' role in tumour development and elucidate future cancer treatment horizons.

Megakaryocytes transfer mitochondria to bone marrow mesenchymal stromal cells to lower platelet activation

Newly produced platelets acquire a low activation state, but whether the megakaryocyte plays a role in this outcome has not been fully uncovered. Mesenchymal stem cells (MSCs) were previously shown to promote platelet production and lower platelet activation. We found that healthy megakaryocytes transfer mitochondria to MSCs, which is mediated by connexin 43 (Cx43) gap junctions on MSCs and leads to platelets at a low energetic state with increased LYN activation, characteristic of resting platelets with increased LYN activation, characteristic of resting platelets. On the contrary, MSCs have a limited ability to transfer mitochondria to megakaryocytes. Sickle cell disease (SCD) is characterized by hemolytic anemia and results in heightened platelet activation, contributing to numerous disease complications. Platelets in SCD mice and human samples had a heightened energetic state with increased glycolysis. MSC exposure to heme in SCD led to decreased Cx43 expression and a reduced ability to uptake mitochondria from megakaryocytes. This prevented LYN activation in platelets and contributed to increased platelet activation at steady state. Altogether, our findings demonstrate an effect of hemolysis in the microenvironment leading to increased platelet activation in SCD. These findings have the potential to inspire new therapeutic targets to relieve thrombosis-related complications of SCD and other hemolytic conditions.

Mitochondrial quality control in hematopoietic stem cells: mechanisms, implications, and therapeutic opportunities

Mitochondrial quality control (MQC) is a critical mechanism for maintaining mitochondrial function and cellular metabolic homeostasis, playing an essential role in the self-renewal, differentiation, and long-term stability of hematopoietic stem cells (HSCs). Recent research highlights the central importance of MQC in HSC biology, particularly the roles of mitophagy, mitochondrial biogenesis, fission, fusion and mitochondrial transfer in regulating HSC function. Mitophagy ensures the removal of damaged mitochondria, maintaining low levels of reactive oxygen species (ROS) in HSCs, thereby preventing premature aging and functional decline. Concurrently, mitochondrial biogenesis adjusts key metabolic regulators such as mitochondrial transcription factor A (TFAM) and peroxisome proliferator-activated receptor-γ coactivator 1α (PGC-1α) to meet environmental demands, ensuring the metabolic needs of HSCs are met. Additionally, mitochondrial transfer, as an essential form of intercellular material exchange, facilitates the transfer of functional mitochondria from bone marrow stromal cells to HSCs, contributing to damage repair and metabolic support. Although existing studies have revealed the significance of MQC in maintaining HSC function, the precise molecular mechanisms and interactions among different regulatory pathways remain to be fully elucidated. Furthermore, the potential role of MQC dysfunction in hematopoietic disorders, including its involvement in disease progression and therapeutic resistance, is not yet fully understood. This review discusses the molecular mechanisms of MQC in HSCs, its functions under physiological and pathological conditions, and its potential therapeutic applications. By summarizing the current progress in this field, we aim to provide insights for further research and the development of innovative treatment strategies.

Microvesicles carrying EV71 virions cross BBB through endocytic pathway to induce brain injury

Enterovirus 71 (EV71) is a major etiologic pathogen for hand-foot-and-mouth disease (HFMD) in young children. Severe cases of EV71 infection could lead to neurological complications and even death, while the mechanism inducing neurological complications remains poorly understood. In this study, we firstly proved that microvesicles (MVs) could carry EV71 virions and mediate a higher efficiency in infection. Utilizing an in vitro blood-brain barrier (BBB) model, we observed that MVs containing virions (MVsEV71) could cross the BBB with greater efficiency compared to EV71 alone. Through in vivo imaging, we confirmed the ability of MVs to cross the BBB. qPCR assays showed a higher copy number of EV71 in both blood and brain samples in the mice treated with MVsEV71 compared to those treated with free EV71. Also, our investigation unveiled that MVsEV71 infection of animals induced cerebral hemorrhage and more severe inflammatory infiltration in the brain compared to animals infected by EV71 in vivo. Furthermore, we found a reduction in the expression of junction proteins such as zonula occludens-1 (ZO-1) and occludin. Moreover, the uptake of MVs by brain cells was examined using chemical inhibitor to block the endocytic pathway. Our experiments elucidated that the internalization of MVs occurred via a non-clathrin-dependent mechanism and a portion of the internalized MVs proceeded to enter lysosomes. In addition, we identified damaged mitochondria as the "cargo" of MVs, which facilitated MVsEV71 crossing the BBB and inducing cellular apoptosis. Meanwhile, MVsEV71 crossing the BBB further induced mitochondrial damaged and activated NOX4-derived ROS pathway in U251 cells. Taken together, these findings suggested that MVs transported EV71 virions across the BBB, while damaged mitochondria facilitated this process and aggravated the brain injury. Overall, these observations provide new insights into EV71-induced neurogenic complications and present a novel therapeutic target for the treatment of viral encephalitis.

Extracellular Vesicles Alter Trophoblast Function in Pregnancies Complicated by COVID-19

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and resulting coronavirus disease (COVID-19) cause placental dysfunction, which increases the risk of adverse pregnancy outcomes. While abnormal placental pathology resulting from COVID-19 is common, direct infection of the placenta is rare. This suggests that pathophysiology associated with maternal COVID-19, rather than direct placental infection, is responsible for placental dysfunction. We hypothesized that maternal circulating extracellular vesicles (EVs), altered by COVID-19 during pregnancy, contribute to placental dysfunction. To examine this hypothesis, we characterized circulating EVs from pregnancies complicated by COVID-19 and tested their effects on trophoblast cell physiology in vitro. Trophoblast exposure to EVs isolated from patients with an active infection (AI), but not controls, altered key trophoblast functions including hormone production and invasion. Thus, circulating EVs from participants with an AI, both symptomatic and asymptomatic cases, can disrupt vital trophoblast functions. EV cargo differed between participants with COVID-19, depending on the gestational timing of infection, and Controls, which may contribute to the disruption of the placental transcriptome and morphology. Our findings show that COVID-19 can have effects throughout pregnancy on circulating EVs, and circulating EVs are likely to participate in placental dysfunction induced by COVID-19.

Advances in Tracing Techniques: Mapping the Trajectory of Mesenchymal Stem-Cell-Derived Extracellular Vesicles

Mesenchymal stem-cell-derived extracellular vesicles (MSC-EVs) are nanoscale lipid bilayer vesicles secreted by mesenchymal stem cells. They inherit the parent cell's attributes, facilitating tissue repair and regeneration, promoting angiogenesis, and modulating the immune response, while offering advantages like reduced immunogenicity, straightforward administration, and enhanced stability for long-term storage. These characteristics elevate MSC-EVs as highly promising in cell-free therapy with notable clinical potential. It is critical to delve into their pharmacokinetics and thoroughly elucidate their intracellular and in vivo trajectories. A detailed summary and evaluation of existing tracing strategies are needed to establish standardized protocols. Here, we have summarized and anticipated the research progress of MSC-EVs in various biomedical imaging techniques, including fluorescence imaging, bioluminescence imaging, nuclear imaging (PET, SPECT), tomographic imaging (CT, MRI), and photoacoustic imaging. The challenges and prospects of MSC-EV tracing strategies, with particular emphasis on clinical translation, have been analyzed, with promising solutions proposed.

Mitochondria transfer for myelin repair

Demyelination is a common feature of neuroinflammatory and degenerative diseases of the central nervous system (CNS), such as multiple sclerosis (MS). It is often linked to disruptions in intercellular communication, bioenergetics and metabolic balance accompanied by mitochondrial dysfunction in cells such as oligodendrocytes, neurons, astrocytes, and microglia. Although current MS treatments focus on immunomodulation, they fail to stop or reverse demyelination's progression. Recent advancements highlight intercellular mitochondrial exchange as a promising therapeutic target, with potential to restore metabolic homeostasis, enhance immunomodulation, and promote myelin repair. With this review we will provide insights into the CNS intercellular metabolic decoupling, focusing on the role of mitochondrial dysfunction in neuroinflammatory demyelinating conditions. We will then discuss emerging cell-free biotherapies exploring the therapeutic potential of transferring mitochondria via biogenic carriers like extracellular vesicles (EVs) or synthetic liposomes, aimed at enhancing mitochondrial function and metabolic support for CNS and myelin repair. Lastly, we address the key challenges for the clinical application of these strategies and discuss future directions to optimize mitochondrial biotherapies. The advancements in this field hold promise for restoring metabolic homeostasis, and enhancing myelin repair, potentially transforming the therapeutic landscape for neuroinflammatory and demyelinating diseases.

Extracellular vesicles lay the ground for neuronal plasticity by restoring mitochondrial function, cell metabolism and immune balance

Extracellular vesicles (EVs) convey complex signals between cells that can be used to promote neuronal plasticity and neurological recovery in brain disease models. These EV signals are multimodal and context-dependent, making them unique therapeutic principles. This review analyzes how EVs released from various cell sources control neuronal metabolic function, neuronal survival and plasticity. Preferential sites of EV communication in the brain are interfaces between pre- and postsynaptic neurons at synapses, between astrocytes and neurons at plasma membranes or tripartite synapses, between oligodendrocytes and neurons at axons, between microglial cells/macrophages and neurons, and between cerebral microvascular cells and neurons. At each of these interfaces, EVs support mitochondrial function and cell metabolism under physiological conditions and orchestrate neuronal survival and plasticity in response to brain injury. In the injured brain, the promotion of neuronal survival and plasticity by EVs is tightly linked with EV actions on mitochondrial function, cell metabolism, oxidative stress and immune responses. Via the stabilization of cell metabolism and immune balance, neuronal plasticity responses are activated and functional neurological recovery is induced. As such, EV lay the ground for neuronal plasticity.

Surface Components and Biological Interactions of Extracellular Vesicles

Extracellular vesicles (EVs) are critical mediators of intercellular communication, carrying bioactive cargo and displaying diverse surface components that reflect their cellular origins and functions. The EV surface, composed of proteins, lipids, and glycocalyx elements, plays a pivotal role in targeting recipient cells, mediating biological interactions, and enabling selective cargo delivery. This review comprehensively examined the molecular architecture of EV surfaces, linking their biogenesis to functional diversity, and highlights their therapeutic and diagnostic potential in diseases such as cancer and cardiovascular disorders. Additionally, we explore emerging applications of EVs, including machine-learning-assisted analysis, chemical integration, and cross-system combinations. The review also discusses some key challenges in the clinical translation of EV-related technologies.

Isolated Mitochondrial Transplantation as a Novel Treatment for Corneal Chemical Burns

Purpose

This study aimed to investigate the therapeutic potential of isolated mitochondrial transplantation for the restoration of corneal surface injury in mice after corneal chemical burn.

Methods

Mitochondria were isolated from mesenchymal stem cells via ultracentrifugation, followed by an assessment of their purity and viability. The internalization of mitochondria by human corneal epithelial cells was tracked using a live fluorescence imaging system. Apoptosis-related markers and mitochondrial function were measured by Western blotting and flow cytometry, respectively. Mitochondrial morphology was examined using confocal laser scanning microscopy. The therapeutic effects of subconjunctival administration of isolated mitochondria in vivo were evaluated by fluorescein sodium staining and histopathological examination of the corneas.

Results

Our study demonstrates that corneal epithelial cells possess the capacity to internalize isolated exogenous mitochondria in vitro. Under oxidative stress conditions, recipient cells exhibited an enhanced uptake of exogenous mitochondria. We observed a decrease in apoptosis and a reduction in oxidative stress levels within the recipient cells, as well as a partial restoration of mitochondrial function. Notably, after a single subconjunctival injection, corneal epithelial cells were able to use isolated mitochondria to enhance the repair process in a mouse model of corneal acid burn.

Conclusions

Subconjunctival injection of isolated mitochondria promoted the repair of acute corneal burns in mice. The results of our investigation using injection of isolated mitochondria as a treatment modality for corneal chemical burn offers a novel approach to the treatment of ocular disorders associated with mitochondrial dysfunction.

The role of mitochondria transfer in cancer biological behavior, the immune system and therapeutic resistance

Mitochondria play a crucial role as organelles, managing several physiological processes such as redox balance, cell metabolism, and energy synthesis. Initially, the assumption was that mitochondria primarily resided in the host cells and could exclusively transmit from oocytes to offspring by a mechanism known as vertical inheritance of mitochondria. Recent scholarly works, however, suggest that certain cell types transmit their mitochondria to other developmental cell types via a mechanism referred to as intercellular or horizontal mitochondrial transfer. This review details the process of which mitochondria are transferred across cells and explains the impact of mitochondrial transfer between cells on the efficacy and functionality of cancer cells in various cancer forms. Specifically, we review the role of mitochondria transfer in regulating cellular metabolism restoration, excess reactive oxygen species (ROS) generation, proliferation, invasion, metastasis, mitophagy activation, mitochondrial DNA (mtDNA) inheritance, immune system modulation and therapeutic resistance in cancer. Additionally, we highlight the possibility of using intercellular mitochondria transfer as a therapeutic approach to treat cancer and enhance the efficacy of cancer treatments.

The uptake of extracellular vesicles: Research progress in cancer drug resistance and beyond

Extracellular vesicles (EVs) are heterogeneous vesicles released by donor cells that can be taken up by recipient cells, thus inducing cellular phenotype changes. Since their discovery decades ago, roles of EVs in modulating initiation, growth, survival and metastasis of cancer have been revealed. Recent studies from multifaceted perspectives have further detailed the contribution of EVs to cancer drug resistance; however, the role of EV uptake in conferring drug resistance seems to be overlooked. In this comprehensive review, we update the EV subtypes and approaches for determining EV uptake. The biological basis of EV uptake is systematically summarized. Moreover, we focus on the diverse uptake mechanisms by which EVs carry out the intracellular delivery of functional molecules and drug resistance signaling. Furthermore, we highlight how EV uptake confers drug resistance and identify potential strategies for targeting EV uptake to overcome drug resistance. Finally, we discuss the research gap on the role of EV uptake in promoting drug resistance. This updated knowledge provides a new avenue to overcome cancer drug resistance by targeting EV uptake.

Mesenchymal Stem/Stromal Cells (MSCs) from Mouse Pelvic vs. Long Bones Exhibit Disparate Critical Quality Attributes: Implications for Translational Studies

Mesenchymal stem/stromal cells (MSCs) have been exploited as an experimental cell therapy in a broad array of clinical applications but have underperformed based on results from pre-clinical studies due to gaps in translating pre-clinical findings to human patients. Herein, we isolated mouse MSCs from pelvic bone marrow (BMP), a preferred source for human MSCs, and compared their growth, differentiation, and immuno-modulatory activity to those derived from long bone marrow (BML), the traditional source of mouse MSCs. We report that BMP-MSCs exhibit significantly enhanced growth kinetics in 5% and 21% oxygen saturation and superior bi-lineage differentiation and hematopoiesis-supporting activity as compared to BML-MSCs. Additionally, we show that TNF upregulates inducible nitric oxide synthase (NOS2) in BML- and BMP- MSCs and augments their immune suppressive activity in cell-based assays, while interferon-gamma (INFG) upregulates indoleamine, 2-3, dioxygenase (IDO1) and enhances the immune suppressive activity of only BMP-MSCs. These results indicate that mouse MSCs sourced from different bone compartments exhibit measurable differences in critical quality attributes, and these differences are comparable to those observed across species. Based on these differences, BMP- MSCs represent a useful resource to model the behavior of human BM-derived MSCs.

The promise of mitochondria in the treatment of glioblastoma: a brief review

Glioblastoma (GBM) is a prevalent and refractory type of brain tumor. Over the past two decades, there have been minimal advancements in GBM therapy. The current standard treatment involves surgical excision followed by radiation and chemotherapy. Compared to other tumors, GBM is more challenging to treat due to the presence of glioma stem-like cells (GSCs) and the blood-brain barrier, resulting in an extremely low survival rate. Mitochondria play a critical role in tumor respiration, metabolism, and multiple signaling pathways involved in tumor formation, progression, and cell apoptosis. Consequently, mitochondria represent promising targets for developing novel anticancer agents, including those targeting oxidative phosphorylation, reactive oxygen species (ROS), mitochondrial transfer, and mitophagy. This review outlines the mitochondrial-related therapeutic targets in GBM, highlighting the potential of mitochondria as a target for GBM treatment.

Mesenchymal stromal cell therapy: Progress to date and future outlook

In clinical trials, mesenchymal stromal/stem cells (MSCs) have consistently demonstrated safety. However, demonstration of efficacy has been inconsistent and many MSC trials have failed to meet their efficacy endpoint. This disappointing reality is reflected by the limited number MSC therapies approved by regulatory agencies, despite the large number of MSC trials registered on clinicaltrials.gov. Notably, there has been a recent approval of an MSC therapy for pediatric graft-vs.-host disease in the United States, marking the first MSC therapy approved by the U.S. Food and Drug Administration. This review provides a background of the history and potential therapeutic value of MSCs, an overview of MSC products with regulatory approval, and a summary of registered MSC trials. It concludes with a discussion on current and ongoing challenges and questions surrounding MSC therapy that remains to be resolved before becoming available for routine clinical use outside of clinical trials.

Recycle, repair, recover: the role of autophagy in modulating skeletal muscle repair and post-exercise recovery

Skeletal muscle is a highly plastic tissue that can adapt relatively rapidly to a range of stimuli. In response to novel mechanical loading, e.g. unaccustomed resistance exercise, myofibers are disrupted and undergo a period of ultrastructural remodeling to regain full physiological function, normally within 7 days. The mechanisms that underpin this remodeling are believed to be a combination of cellular processes including ubiquitin-proteasome/calpain-mediated degradation, immune cell infiltration, and satellite cell proliferation/differentiation. A relatively understudied system that has the potential to be a significant contributing mechanism to repair and recovery is the autophagolysosomal system, an intracellular process that degrades damaged and redundant cellular components to provide constituent metabolites for the resynthesis of new organelles and cellular structures. This review summarizes our current understanding of the autophagolysosomal system in the context of skeletal muscle repair and recovery. In addition, we also provide hypothetical models of how this system may interact with other processes involved in skeletal muscle remodeling and provide avenues for future research to improve our understanding of autophagy in human skeletal muscle.

Exosome Source Matters: A Comprehensive Review from the Perspective of Diverse Cellular Origins

Exosomes have emerged as promising therapeutic agents in regenerative medicine. This review introduces a novel cell type-oriented perspective to systematically analyze exosomal properties in regenerative therapies. To our knowledge, this review is the first to comprehensively compare exosomes based on cellular source type, offering unprecedented insights into selecting optimal exosome producers for targeted regenerative applications. Factors beyond cellular origin influencing exosomal therapeutic efficacy, such as donor sites and collection methods, are also explored here. By synthesizing key advances, we propose promising research directions in the end. We aim to accelerate the development of more effective exosome-based regenerative therapies and highlight underexplored directions in this rapidly evolving field.

Exosomes in Autoimmune Diseases: A Review of Mechanisms and Diagnostic Applications

Exosomes, small extracellular vesicles secreted by various cell types, have emerged as key players in the pathophysiology of autoimmune diseases. These vesicles serve as mediators of intercellular communication, facilitating the transfer of bioactive molecules such as proteins, lipids, and nucleotide. In autoimmune diseases, exosomes have been implicated in modulating immune responses, oxidative stress, autophagy, gut microbes, and the cell cycle, contributing to disease initiation, progression, and immune dysregulation. Recent advancements in exosome isolation techniques and their molecular characterization have paved the way for exploring their clinical potential as biomarkers and therapeutic targets. This review focuses on the mechanisms by which exosomes influence autoimmune disease development and their potential clinical applications, particularly in diagnosis. The role of exosomes in autoimmune diseases, including systemic lupus erythematosus (SLE), rheumatoid arthritis (RA), type 1 diabetes mellitus (T1DM), inflammatory bowel disease (IBD), and Sjögren's syndrome (SS), is discussed in relation to their involvements in antigen presentation, T-cell activation, and the induction of inflammatory pathways. Additionally, exosome-based biomarkers offer promising non-invasive diagnostic tools for early diagnostic, disease monitoring, and therapeutic response assessment. However, challenges such as standardization of exosome isolation protocols and validation of their clinical significance remain. This review highlights the potential of exosomes as both diagnostic biomarkers and therapeutic targets in autoimmune diseases, emphasizing the need for further research to overcome current limitations and fully harness their clinical value.

A proof-of-concept study in small and large animal models for coupling liver normothermic machine perfusion with mesenchymal stromal cell bioreactors

To fully harness mesenchymal-stromal-cells (MSCs)' benefits during Normothermic Machine Perfusion (NMP), we developed an advanced NMP platform coupled with a MSC-bioreactor and investigated its bio-molecular effects and clinical feasibility using rat and porcine models. The study involved three work packages: 1) Development (n = 5): MSC-bioreactors were subjected to 4 h-liverless perfusion; 2) Rat model (n = 10): livers were perfused for 4 h on the MSC-bioreactor-circuit or with the standard platform; 3) Porcine model (n = 6): livers were perfused using a clinical device integrated with a MSC-bioreactor or in its standard setup. MSCs showed intact stem-core properties after liverless-NMP. Liver NMP induced specific, liver-tailored, changes in MSCs' secretome. Rat livers exposed to bioreactor-based perfusion produced more bile, released less damage and pro-inflammatory biomarkers, and showed improved mithocondrial function than those subjected to standard NMP. MSC-bioreactor integration into a clinical device resulted in no machine failure and perfusion-related injury. This proof-of-concept study presents a novel MSC-based liver NMP platform that could reduce the deleterious effects of ischemia/reperfusion before transplantation.

Therapeutic Potential of Mesenchymal Stem Cell-Derived Exosomes in Spinal Cord Injury

Spinal cord injury (SCI) can lead to severe motor and sensory dysfunction, with a high rate of disability and mortality. Due to the complicated pathological process of SCI, there is no effective clinical treatment strategy at present. Although mesenchymal stem cells (MSCs) are effective in the treatment of SCI, their application is limited by factors such as low survival rate, cell dedifferentiation, tumorigenesis, blood-brain barrier, and immune rejection. Fortunately, there is growing evidence that most of the biological and therapeutic effects of MSCs may be mediated by the release of paracrine factors, which are extracellular vesicles called exosomes. Exosomes are small endosomal vesicles with bilaminar membranes that have recently been recognized as key mediators for communication between cells and tissues through the transfer of proteins, lipids, nucleic acids, cytokines, and growth factors. Mesenchymal stem cell-derived exosomes (MSC-exos) play a critical role in SCI repair by promoting angiogenesis and axonal growth, regulating inflammation and immune response, inhibiting apoptosis, and maintaining the integrity of the blood-spinal cord barrier. Furthermore, they can be used to transport genetic material or drugs to target cells, and their relatively small size allows them to permeate the blood-brain barrier. Studies have demonstrated that some exosomal miRNAs derived from MSCs play a significant role in the treatment of SCI. In this review, we summarize recent research advances in MSC-exos and exosomal miRNAs in SCI therapy to better understand this emerging cell-free therapeutic strategy and discuss the advantages and challenges of MSC-exos in future clinical applications.

TSPO exacerbates sepsis-induced cardiac dysfunction by inhibiting p62-Mediated autophagic flux via the ROS-RIP1/RIP3-exosome axis

Septic cardiomyopathy (SCM) is a critical complication of sepsis, primarily attributed to mitochondrial dysfunction and impaired autophagic flux. This study explores the role of translocator protein (TSPO) in SCM pathogenesis and assesses its potential as a therapeutic target. We identified increased TSPO expression in plasma samples from sepsis patients, with further validation in septic rats and LPS-stimulated H9C2 cardiomyocytes. Elevated TSPO disrupted mitochondrial function, leading to increased reactive oxygen species (ROS) production and activation of the RIP1/RIP3 pathway, which hindered p62-positive autophagosome degradation and promoted inflammation. Moreover, exosome release containing TSPO-positive autophagosomes into plasma may exacerbate systemic inflammation. NADH, identified as a TSPO-binding molecule, restored autophagic flux, improved mitochondrial function, and enhanced cardiac performance and survival in septic rats. These findings suggest that targeting TSPO with NADH could alleviate mitochondrial dysfunction and inflammatory responses in SCM, providing a promising therapeutic strategy for sepsis-induced cardiac injury.

Extracellular vesicles secreted by leukemic cells as mediators of dysregulated hematopoiesis: acute myeloid leukemia as a case in point

INTRODUCTION

Acute myeloid leukemia (AML) cells exhibit a profound capacity for resistance to conventional chemotherapeutic agents, posing a substantial challenge to existing therapeutic paradigms. Interestingly, this happens in the face of a luxuriant proliferation of leukemic blasts in the peripheral blood. This paradox of concurrent proliferative activity and cellular quiescence underscores a complex biological phenomenon that is intricately mediated by AML-derived Extracellular vesicles (EVs).

AREAS COVERED

An extensive literature review search was done on PubMed/Scopus/Web of Sciences databases to identify studies published between 2013 and 2024 elucidating and demonstrating the effect of AML-derived EVs, Microvesicles (MVs) and Exosomes (Exos) in regulating the normal and dysregulated bone marrow (BM) niche.

EXPERT OPINION

The review delves into understanding the molecular mechanisms underlying the dual behavior of AML cells - proliferation and quiescence, with a special focus on the role of the EVs and their subtypes viz. Exos and MVs in establishing a discrete BM microenvironment that is subversive to chemotherapy. It offers a novel perspective on the intricate interplay between the leukemic cells and their microenvironment, with implications for therapeutic interventions targeting AML persistence and drug resistance.

Extracellular Vesicles: Advanced Tools for Disease Diagnosis, Monitoring, and Therapies

Extracellular vesicles (EVs) are a heterogeneous group of membrane-encapsulated vesicles released by cells into the extracellular space. They play a crucial role in intercellular communication by transporting bioactive molecules such as proteins, lipids, and nucleic acids. EVs can be detected in body fluids, including blood plasma, urine, saliva, amniotic fluid, breast milk, and pleural ascites. The complexity and diversity of EVs require a robust and standardized approach. By adhering to standardized protocols and guidelines, researchers can ensure the consistency, purity, and reproducibility of isolated EVs, facilitating their use in diagnostics, therapies, and research. Exosomes and microvesicles represent an exciting frontier in modern medicine, with significant potential to transform the diagnosis and treatment of various diseases with an important role in personalized medicine and precision therapy. The primary objective of this review is to provide an updated analysis of the significance of EVs by highlighting their mechanisms of action and exploring their applications in the diagnosis and treatment of various diseases. Additionally, the review addresses the existing limitations and future potential of EVs, offering practical recommendations to resolve current challenges and enhance their viability for clinical use. This comprehensive approach aims to bridge the gap between EV research and its practical application in healthcare.

Inter- and intracellular mitochondrial communication: signaling hubs in aging and age-related diseases

Mitochondria are versatile and complex organelles that can continuously communicate and interact with the cellular milieu. Deregulated communication between mitochondria and host cells/organelles has significant consequences and is an underlying factor of many pathophysiological conditions, including the process of aging. During aging, mitochondria lose function, and mitocellular communication pathways break down; mitochondrial dysfunction interacts with mitochondrial dyscommunication, forming a vicious circle. Therefore, strategies to protect mitochondrial function and promote effective communication of mitochondria can increase healthy lifespan and longevity, which might be a new treatment paradigm for age-related disorders. In this review, we comprehensively discuss the signal transduction mechanisms of inter- and intracellular mitochondrial communication, as well as the interactions between mitochondrial communication and the hallmarks of aging. This review emphasizes the indispensable position of inter- and intracellular mitochondrial communication in the aging process of organisms, which is crucial as the cellular signaling hubs. In addition, we also specifically focus on the status of mitochondria-targeted interventions to provide potential therapeutic targets for age-related diseases.

Mitochondrial dysfunction and Alzheimer's disease: pathogenesis of mitochondrial transfer

In recent years, mitochondrial transfer has emerged as a universal phenomenon intertwined with various systemic physiological and pathological processes. Alzheimer's disease (AD) is a multifactorial disease, with mitochondrial dysfunction at its core. Although numerous studies have found evidence of mitochondrial transfer in AD models, the precise mechanisms remain unclear. Recent studies have revealed the dynamic transfer of mitochondria in Alzheimer's disease, not only between nerve cells and glial cells, but also between nerve cells and glial cells. In this review, we explore the pathways and mechanisms of mitochondrial transfer in Alzheimer's disease and how these transfer activities contribute to disease progression.

Recent Advancements in Imaging Techniques for Individual Extracellular Vesicles

Extracellular vesicles (EVs), secreted from most cells, are small lipid membranes of vesicles of 30 to 1000 nm in diameter and contain nucleic acids, proteins, and intracellular organelles originating from donor cells. EVs play pivotal roles in intercellular communication, particularly in forming niches for cancer cell metastasis. However, EVs derived from donor cells exhibit significant heterogeneity, complicating the investigation of EV subtypes using ensemble averaging methods. In this context, we highlight recent studies that characterize individual EVs using advanced techniques, including single-fluorescent-particle tracking, single-metal-nanoparticle tracking, single-non-label-particle tracking, super-resolution microscopy, and atomic force microscopy. These techniques have facilitated high-throughput analyses of the properties of individual EV particles such as their sizes, compositions, and physical properties. Finally, we address the challenges that need to be resolved via single-particle (-molecule) imaging and super-resolution microscopy in future research.

Mitochondria break free: Mitochondria-derived vesicles in aging and associated conditions

Mitophagy is the intracellular recycling system that disposes damaged/inefficient mitochondria and allows biogenesis of new organelles to ensure mitochondrial quality is optimized. Dysfunctional mitophagy has been implicated in human aging and diseases. Multiple evolutionarily selected, redundant mechanisms of mitophagy have been identified, but their specific roles in human health and their potential exploitation as therapeutic targets are unclear. Recently, the characterization of the endosomal-lysosomal system has revealed additional mechanisms of mitophagy and mitochondrial quality control that operate via the production of mitochondria-derived vesicles (MDVs). Circulating MDVs can be isolated and characterized to provide an unprecedented opportunity to study this type of mitochondrial recycling in vivo and to relate it to human physiology and pathology. Defining the role of MDVs in human physiology, pathology, and aging is hampered by the lack of standardized methods to isolate, validate, and characterize these vesicles. Hence, some basic questions about MDVs remain unanswered. While MDVs are generated directly through the extrusion of mitochondrial membranes within the cell, a set of circulating extracellular vesicles leaking from the endosomal-lysosomal system and containing mitochondrial portions have also been identified and warrant investigation. Preliminary research indicates that MDV generation serves multiple biological roles and contributes to restoring cell homeostasis. However, studies have shown that MDVs may also be involved in pathological conditions. Therefore, further research is warranted to establish when/whether MDVs are supporting disease progression and/or are extracting damaged mitochondrial components to alleviate cellular oxidative burden and restore redox homeoastasis. This information will be relevant for exploiting these vesicles for therapeutic purpose. Herein, we provide an overview of preclinical and clinical studies on MDVs in aging and associated conditions and discuss the interplay between MDVs and some of the hallmarks of aging (mitophagy, inflammation, and proteostasis). We also outline open questions on MDV research that should be prioritized by future investigations.

Transfer and fates of damaged mitochondria: role in health and disease

Intercellular communication is pivotal in mediating the transfer of mitochondria from donor to recipient cells. This process orchestrates various biological functions, including tissue repair, cell proliferation, differentiation and cancer invasion. Typically, dysfunctional and depolarized mitochondria are eliminated through intracellular or extracellular pathways. Nevertheless, increasing evidence suggests that intercellular transfer of damaged mitochondria is associated with the pathogenesis of diverse diseases. This review investigates the prevalent triggers of mitochondrial damage and the underlying mechanisms of mitochondrial transfer, and elucidates the role of directional mitochondrial transfer in both physiological and pathological contexts. Additionally, we propose potential previously unknown mechanisms mediating mitochondrial transfer and explore their prospective roles in disease prevention and therapy.

Potential therapeutic effects and nano-based delivery systems of mesenchymal stem cells and their isolated exosomes to alleviate acute respiratory distress syndrome caused by COVID-19

The severe respiratory effects of the coronavirus disease 2019 (COVID-19) pandemic have necessitated the immediate development of novel treatments. The majority of COVID-19-related fatalities are due to acute respiratory distress syndrome (ARDS). Consequently, this virus causes massive and aberrant inflammatory conditions, which must be promptly managed. Severe respiratory disorders, notably ARDS and acute lung injury (ALI), may be treated safely and effectively using cell-based treatments, mostly employing mesenchymal stem cells (MSCs). Since the high potential of these cells was identified, a great deal of research has been conducted on their use in regenerative medicine and complementary medicine. Multiple investigations have demonstrated that MSCs and their products, especially exosomes, inhibit inflammation. Exosomes serve a critical function in intercellular communication by transporting molecular cargo from donor cells to receiver cells. MSCs and their derived exosomes (MSCs/MSC-exosomes) may improve lung permeability, microbial and alveolar fluid clearance, and epithelial and endothelial repair, according to recent studies. This review focuses on COVID-19-related ARDS clinical studies involving MSCs/MSC-exosomes. We also investigated the utilization of Nano-delivery strategies for MSCs/MSC-exosomes and anti-inflammatory agents to enhance COVID-19 treatment.

Mitochondrial Dysfunction in Cardiac Disease: The Fort Fell

Myocardial cells and the extracellular matrix achieve their functions through the availability of energy. In fact, the mechanical and electrical properties of the heart are heavily dependent on the balance between energy production and consumption. The energy produced is utilized in various forms, including kinetic, dynamic, and thermal energy. Although total energy remains nearly constant, the contribution of each form changes over time. Thermal energy increases, while dynamic and kinetic energy decrease, ultimately becoming insufficient to adequately support cardiac function. As a result, toxic byproducts, unfolded or misfolded proteins, free radicals, and other harmful substances accumulate within the myocardium. This leads to the failure of crucial processes such as myocardial contraction-relaxation coupling, ion exchange, cell growth, and regulation of apoptosis and necrosis. Consequently, both the micro- and macro-architecture of the heart are altered. Energy production and consumption depend on the heart's metabolic resources and the functional state of the cardiac structure, including cardiomyocytes, non-cardiomyocyte cells, and their metabolic and energetic behavior. Mitochondria, which are intracellular organelles that produce more than 95% of ATP, play a critical role in fulfilling all these requirements. Therefore, it is essential to gain a deeper understanding of their anatomy, function, and homeostatic properties.

Unveiling the power of mitochondrial transfer in cancer progression: a perspective in ovarian cancer

Mitochondria are dynamic organelles integral to metabolic processes, coordination of essential biological pathways, and oncogenesis and tumor progression. Recent studies have revealed that mitochondria can be transferred between cells via multiple mechanisms, implicating their involvement in the pathogenesis and progression of ovarian cancer. This review provides a comprehensive analysis of intercellular mitochondrial transfer within the context of ovarian cancer and its tumor microenvironment. We also propose targeted pathways and therapeutic strategies that could be utilized to modulate diseases associated with mitochondrial transfer therapy. Finally, we examine recent advancements in this field and identify several unresolved questions.

Immune System-Related Plasma Pathogenic Extracellular Vesicle Subpopulations Predict Osteoarthritis Progression

Certain molecules found on the surface or within the cargo of extracellular vesicles (EVs) are linked to osteoarthritis (OA) severity and progression. We aimed to identify plasma pathogenic EV subpopulations that can predict knee radiographic OA (rOA) progression. We analyzed the mass spectrometry-based proteomic data of plasma EVs and synovial fluid (SF) EVs from knee OA patients (n = 16, 50% female). The identified surface markers of interest were further evaluated in plasma EVs from an independent cohort of knee OA patients (n = 30, 47% female) using flow cytometry. A total of 199 peptides with significant correlation between plasma and SF EVs were identified. Of these, 41.7% were linked to immune system processes, 15.5% to inflammatory responses, and 16.7% to the complement system. Crucially, five previously identified knee rOA severity-indicating surface markers-FGA, FGB, FGG, TLN1, and AMBP-were confirmed on plasma EV subpopulations in an independent cohort. These markers' baseline frequencies on large plasma EVs predicted rOA progression with an AUC of 0.655-0.711. Notably, TLN1 was expressed in OA joint tissue, whereas FGA, FGB, FGG, and AMBP were predominantly liver derived. These surface markers define specific pathogenic EV subpopulations, offering potential OA prognostic biomarkers and novel therapeutic targets for disease modification.

Mitochondria-Rich Microvesicles Alleviate CNI ED by Transferring Mitochondria and Suppressing Local Ferroptosis

Purpose

Erectile dysfunction (ED) frequently arises as a complication of pelvic surgeries, including rectal and prostate surgery, and has no definitive cure. This study explored whether mitochondria-rich microvesicles (MVs) can be used to treat ED stemming from cavernous nerve injury (CNI) and investigated its potential mechanisms.

Methods

We isolated MVs and mitochondria (MT) from PC12. The apoptosis rate, mitochondrial membrane potential (MMP), reactive oxygen species (ROS), mitochondrial derived reactive oxygen species (mtROS), iron content, malondialdehyde (MDA) content and endogenous antioxidant system activity of corpus cavernosum smooth muscle cells (CCSMCs) cultured with MVs and MT were detected in vitro. In vivo, twenty-four male Sprague Dawley rats were randomly divided into four groups: sham operation group and CNI group were injected with PBS, MVs and MT respectively. After fourteen days of treatment, the erectile function was measured and penile tissues were collected for histological analysis. Subsequently, inhibition of mitochondria in MV was performed to explore the mechanism of the rescue experiment.

Results

The CCSMCs, PC12-MVs and PC12-MT were successfully isolated and identified. After MVs culture, apoptosis rate, ROS, mtROS, iron content and MDA content of CCSMCs were significantly decreased, while MMP and the activities of endogenous antioxidant system were increased. MVs transplantation can significantly restore erectile function and smooth muscle content in CNIED rats. The rescue experiment suggested that MVs exerted the above therapeutic effect by transferring mitochondria within it.

Conclusion

MVs transplantation significantly improve erectile function in CNI ED rats. MVs may play a role in anti-OS and anti-ferroptosis at the transplant site through efficient transfer of mitochondria, providing a potential treatment vehicle for CNI ED.

From dysfunction to healing: advances in mitochondrial therapy for Osteoarthritis

Osteoarthritis (OA) is a chronic degenerative joint condition characterised by cartilage deterioration and changes in bone morphology, resulting in pain and impaired joint mobility. Investigation into the pathophysiological mechanisms underlying OA has highlighted the significance of mitochondrial dysfunction in its progression. Mitochondria, which are cellular organelles, play a crucial role in regulating energy metabolism, generating reactive oxygen species, and facilitating essential biological processes including apoptosis. In recent years, the utilisation of exogenous drugs and MT to improve mitochondrial function in chondrocytes has shown great promise in OA treatment. Numerous studies have investigated the potential of stem cells and extracellular vesicles in mitochondrial transfer. This review aims to explore the underlying mechanisms of mitochondrial dysfunction in OA and assess the progress in utilising mitochondrial transfer as a therapeutic approach for this disease.

Mesenchymal stem cell application in pulmonary disease treatment with emphasis on their interaction with lung-resident immune cells

Due to the vital importance of the lungs, lung-related diseases and their control are very important. Severe inflammatory responses mediated by immune cells were among the leading causes of lung tissue pathology and damage during the COVID-19 pandemic. In addition, uncontrolled immune cell responses can lead to lung tissue damage in other infectious and non-infectious diseases. It is essential to control immune responses in a way that leads to homeostasis. Immunosuppressive drugs only suppress inflammatory responses and do not affect the homeostasis of reactions. The therapeutic application of mesenchymal stem cells (MSCs), in addition to restoring immune homeostasis, can promote the regeneration of lung tissue through the production of growth factors and differentiation into lung-related cells. However, the communication between MSCs and immune cells after treatment of pulmonary diseases is essential, and investigating this can help develop a clinical perspective. Different studies in the clinical phase showed that MSCs can reverse fibrosis, increase regeneration, promote airway remodeling, and reduce damage to lung tissue. The proliferation and differentiation potential of MSCs is one of the mechanisms of their therapeutic effects. Furthermore, they can secrete exosomes that affect the function of lung cells and immune cells and change their function. Another important mechanism is that MSCs reduce harmful inflammatory responses through communication with innate and adaptive immune cells, which leads to a shift of the immune system toward regulatory and hemostatic responses.

Mitochondrial Bioenergetics of Functional Wound Closure is Dependent on Macrophage-Keratinocyte Exosomal Crosstalk

Tissue nanotransfection (TNT)-based fluorescent labeling of cell-specific exosomes has shown that exosomes play a central role in physiological keratinocyte-macrophage (mϕ) crosstalk at the wound-site. Here, we report that during the early phase of wound reepithelialization, macrophage-derived exosomes (Exomϕ), enriched with the outer mitochondrial membrane protein TOMM70, are localized in leading-edge keratinocytes. TOMM70 is a 70 kDa adaptor protein anchored in the mitochondrial outer membrane and plays a critical role in maintaining mitochondrial function and quality. TOMM70 selectively recognizes cytosolic chaperones by its tetratricopeptide repeat (TPR) domain and facilitates the import of preproteins lacking a positively charged mitochondrial targeted sequence. Exosomal packaging of TOMM70 in mϕ was independent of mitochondrial fission. TOMM70-enriched Exomϕ compensated for the hypoxia-induced depletion of epidermal TOMM70, thereby rescuing mitochondrial metabolism in leading-edge keratinocytes. Thus, macrophage-derived TOMM70 is responsible for the glycolytic ATP supply to power keratinocyte migration. Blockade of exosomal uptake from keratinocytes impaired wound closure with the persistence of proinflammatory mϕ in the wound microenvironment, pointing toward a bidirectional crosstalk between these two cell types. The significance of such bidirectional crosstalk was established by the observation that in patients with nonhealing diabetic foot ulcers, TOMM70 is deficient in keratinocytes of wound-edge tissues.

Mesenchymal Stem Cells and Their Derived Exosomes Mitigated Hepatic Cirrhosis in Rats by Altering the Expression of miR-23b and miR-221

Background

The therapeutic effect of mesenchymal stem cells (MSCs) in liver cirrhosis is limited by their entrapment in the pulmonary vessels. Thus, the use of MSC-derived exosomes has become a promising strategy. The current work aimed to compare the role of human umbilical cord blood-MSCs (hUCB-MSCs) and their derived exosomes in the alleviation of liver cirrhosis focusing on the role of miR-23b and miR-221 and their direct effectors in inflammatory and autophagic pathways.

Methods

Rats were divided into six groups normal controls (negative control), liver cirrhosis group (positive control), liver cirrhotic rats that received conditioned media, liver cirrhotic rats that received hUCB-MSCs, cirrhotic rats that received exosomes, and cirrhotic rats that received both hUCB-MSCs and exosomes. The messenger RNA expression of transforming growth factor-β (TGF-β), Matrix metalloproteinase 9 (MMP 9), fibronectin, collagen type-1 (col1), alpha-smooth muscle actin (α-SMA), Suppressor of Mothers Against Decapentaplegic (SMAD) 2 and 7, Beclin, P62, and light chain 3 (LC3) were evaluated by quantitative real-time polymerase chain reaction. Immunohistochemical staining for Beclin, P62, and LC3 was performed.

Results

The treatment of cirrhotic rats with hUCB-MSCs, exosomes, or the combination of them significantly downregulated miRNA-221, fibronectin, collagen I, α-SMA, Smad2 (P<0.001, for each), and P62 (P=0.032, P<0.001, P<0.001, respectively). Additionally, the treatment of cirrhotic rats with hUCB-MSCs, exosomes, or the combination of them significantly upregulated mTOR, Beclin, LC3, and Smad7 (P<0.001, for each) and miRNA-23 (P=0.021, P<0.001, P<0.001, respectively).

Conclusion

hUCB-MSCs and their derived exosomes ameliorated liver cirrhosis by anti-inflammatory and anti-fibrotic effects besides modulation of autophagy. The exosomes had a better improvement effect either alone or combined with hUCB-MSCs, as proved by improvement in liver function tests, and molecular, histopathological, and immunohistochemical profiles.

Role of mesenchymal stem cells in sepsis and their therapeutic potential in sepsis‑associated myopathy (Review)

Sepsis‑induced myopathy (SIM) is one of the leading causes of death in critically ill patients. SIM mainly involves the respiratory and skeletal muscles of patients, resulting in an increased risk of lung infection, aggravated respiratory failure, and prolonged mechanical ventilation and hospital stay. SIM is also an independent risk factor associated with increased mortality in critically ill patients. At present, no effective treatment for SIM has yet been established. However, mesenchymal stem cells (MSCs) have emerged as a promising therapeutic approach and have been utilized in the treatment of various clinical conditions. A significant body of basic and clinical research supports the efficacy of MSCs in managing sepsis and muscle‑related diseases. This literature review aims to explore the relationship between MSCs and sepsis, as well as their impact on skeletal muscle‑associated diseases. Additionally, the present review discusses the potential mechanisms and therapeutic benefits of MSCs in the context of SIM.

Mitochondrial Extracellular Vesicles (mitoEVs): Emerging mediators of cell-to-cell communication in health, aging and age-related diseases

Mitochondria are metabolic and signalling hubs that integrate a plethora of interconnected processes to maintain cell homeostasis. They are also dormant mediators of inflammation and cell death, and with aging damages affecting mitochondria gradually accumulate, resulting in the manifestation of age-associated disorders. In addition to coordinate multiple intracellular functions, mitochondria mediate intercellular and inter-organ cross talk in different physiological and stress conditions. To fulfil this task, mitochondrial signalling has evolved distinct and complex conventional and unconventional routes of horizontal/vertical mitochondrial transfer. In this regard, great interest has been focused on the ability of extracellular vesicles (EVs), such as exosomes and microvesicles, to carry selected mitochondrial cargoes to target cells, in response to internal and external cues. Over the past years, the field of mitochondrial EVs (mitoEVs) has grown exponentially, revealing unexpected heterogeneity of these structures associated with an ever-expanding mitochondrial function, though the full extent of the underlying mechanisms is far from being elucidated. Therefore, emerging subsets of EVs encompass exophers, migrasomes, mitophers, mitovesicles, and mitolysosomes that can act locally or over long-distances to restore mitochondrial homeostasis and cell functionality, or to amplify disease. This review provides a comprehensive overview of our current understanding of the biology and trafficking of MitoEVs in different physiological and pathological conditions. Additionally, a specific focus on the role of mitoEVs in aging and the onset and progression of different age-related diseases is discussed.

Mitochondrial transfer from mesenchymal stem cells: Mechanisms and functions

Mesenchymal stem cells based therapy has been used in clinic for almost 20 years and has shown encouraging effects in treating a wide range of diseases. However, the underlying mechanism is far more complicated than it was previously assumed. Mitochondria transfer is one way that recently found to be employed by mesenchymal stem cells to exert its biological effects. As one way of exchanging mitochondrial components, mitochondria transfer determines both mesenchymal stem cells and recipient cell fates. In this review, we describe the factors that contribute to MSCs-MT. Then, the routes and mechanisms of MSCs-MT are summarized to provide a theoretical basis for MSCs therapy. Besides, the advantages and disadvantages of MSCs-MT in clinical application are analyzed.

Research hotspots and trends of mesenchymal stem cell-derived extracellular vesicles for drug delivery: a bibliometric and visualization analysis from 2013 to 2023

Introduction

Our study aims to provide a comprehensive overview of mesenchymal stem cell-derived extracellular vesicles (MSC-EVs) in drug delivery research, focusing on the period between 2013 and 2023. Given the increasing global interest in this field, we utilized bibliometric tools to explore publication trends, key contributors, and thematic research clusters.

Methods

Data was collected from the Web of Science (WoS) database, and an in-depth bibliometric analysis was conducted using VOSviewer. The analysis encompassed bibliographic coupling, co-citation, co-authorship, and co-occurrence trends, offering a structured insight into global research activity. We also employed Citespace to further analyze thematic clusters in this domain.

Results

Our analysis revealed a total of 1,045 publications related to MSC-EVs in drug delivery over the past decade, showing a steady increase in research output. China led in publication count, H-index, prolific authors, and research funding, while the United States ranked highest in total citations, average citation counts, and H-index performance. Pharmaceutics emerged as the leading journal by publication volume, with the Journal of Controlled Release having the strongest total link strength. Top institutions driving research included Shanghai Jiao Tong University, Zhejiang University, and Harvard University. VOSviewer analysis identified four major research clusters: tissue engineering, cancer, neurological diseases, and targeted delivery. Citespace analysis refined this further into ten thematic areas, including differentiation, tissue regeneration, and drug resistance.

Discussion

This bibliometric assessment provides a holistic visualization of the research landscape for MSC-EVs in drug delivery, underlining the significant contributions of China and the United States. Our findings underscore the increasing global importance of MSC-EV research and highlight emerging themes that will likely guide future research directions. The insights from this study offer a foundational framework for identifying nascent frontiers in MSC-EV-based drug delivery.

Advancements in Research on Mesenchymal Stem-Cell-Derived Exosomal miRNAs: A Pivotal Insight into Aging and Age-Related Diseases

Mesenchymal stem cells (MSCs) are capable of differentiating into various cell types and play a crucial role in repairing aging tissues and diseased organs. Aging manifests as a gradual loss of cellular, tissue, and organ function, leading to the progression of pathologies. Exosomes (Exos) are extracellular vesicles secreted by cells, which maintain cellular homeostasis, clear cellular debris, and facilitate communication between cells and organs. This review provides a comprehensive summary of the mechanisms for the synthesis and sorting of MSC-Exo miRNAs and summarizes the current research status of MSCs-Exos in mitigating aging and age-related diseases. It delves into the underlying molecular mechanisms, which encompass antioxidative stress, anti-inflammatory response, and the promotion of angiogenesis. Additionally, this review also discusses potential challenges in and future strategies for advancing MSC-Exo miRNA-based therapies in the treatment of aging and age-related diseases.

Effect of Unfractionated Heparin Dose on Complement Activation and Selected Extracellular Vesicle Populations during Extracorporeal Membrane Oxygenation

Extracorporeal membrane oxygenation (ECMO) provides critical support for patients with severe cardiopulmonary dysfunction. Unfractionated heparin (UFH) is used for anticoagulation to maintain circuit patency and avoid thrombotic complications, but it increases the risk of bleeding. Extracellular vesicles (EVs), nano-sized subcellular spheres with potential pro-coagulant properties, are released during cellular stress and may serve as potential targets for monitoring anticoagulation, particularly in thromboinflammation. We investigated the impact of UFH dose during ECMO therapy at the coagulation-inflammation interface level, focusing on complement activation and changes in circulating large EV (lEV) subsets. In a post hoc analysis of a multicenter randomized controlled trial comparing two anticoagulation management algorithms, we examined lEV levels and complement activation in 23 veno-venous-ECMO patients stratified by UFH dose. Blood samples were collected at different time points and grouped into three phases of ECMO therapy: initiation (day 1), mid (days 3-4), and late (days 6-7). Immunoassays detected complement activation, and flow cytometry analyzed lEV populations with an emphasis on mitochondria-carrying subsets. Patients receiving <15 IU/kg/h UFH exhibited higher levels of the complement activation product C5a and soluble terminal complement complex (sC5b-9). Lower UFH doses were linked to increased endothelial-derived lEVs, while higher doses were associated with elevated RBC-derived and mitochondria-positive lEVs. Our findings suggest the potential theranostic relevance of EV detection at the coagulation-inflammation interface. Further research is needed to standardize EV detection methods and validate these findings in larger ECMO patient cohorts.

Retinal damage promotes mitochondrial transfer in the visual system of a mouse model of Leber hereditary optic neuropathy

Lenadogene nolparvovec is a gene therapy which has been developed to treat Leber hereditary optic neuropathy (LHON) caused by a point mutation in the mitochondrial NADH dehydrogenase 4 (ND4) gene. Clinical trials have demonstrated a significant improvement of visual acuity up to 5 years after treatment by lenadogene nolparvovec but, surprisingly, unilateral treatment resulted in bilateral improvement of vision. This contralateral effect - similarly observed with other gene therapy products in development for MT-ND4-LHON - is supported by the migration of viral vector genomes and their transcripts to the contralateral eye, as reported in animals, and post-mortem samples from two patients. In this study, we used an AAV2 encoding fluorescent proteins targeting mitochondria to investigate whether these organelles themselves could transfer from the treated eye to the fellow one. We found that mitochondria travel along the visual system (optic chiasm and primary visual cortex) and reach the contralateral eye (optic nerve and retina) in physiological conditions. We also observed that, in a rotenone-induced model of retinal damage mimicking LHON, mitochondrial transfer from the healthy to the damaged eye was accelerated and enhanced. Our results thus provide a further explanation for the contralateral beneficial effect observed during clinical studies with lenadogene nolparvovec.

Mitochondrion-based organellar therapies for central nervous system diseases

As most traditional drugs used to treat central nervous system (CNS) diseases have a single therapeutic target, many of them cannot treat complex diseases or diseases whose mechanism is unknown and cannot effectively reverse the root changes underlying CNS diseases. This raises the question of whether multiple functional components are involved in the complex pathological processes of CNS diseases. Organelles are the core functional units of cells, and the replacement of damaged organelles with healthy organelles allows the multitargeted and integrated modulation of cellular functions. The development of therapies that target independent functional units in the cell, specifically, organelle-based therapies, is rapidly progressing. This article comprehensively discusses the pathogenesis of mitochondrial homeostasis disorders, which involve mitochondria, one of the most important organelles in CNS diseases, and the machanisms of mitochondrion-based therapies, as well as current preclinical and clinical studies on the efficacy of therapies targeting mitochondrial to treat CNS diseases, to provide evidence for use of organelle-based treatment strategies in the future.