Mechanisms behind therapeutic potentials of mesenchymal stem cell mitochondria transfer/delivery

Exosomes in stroke management: A promising paradigm shift in stroke therapy

Effective treatment methods for stroke, a common cerebrovascular disease with a high mortality rate, are still being sought. Exosome therapy, a form of acellular therapy, has demonstrated promising efficacy in various diseases in animal models; however, there is currently insufficient evidence to guide the clinical application of exosome in patients with stroke. This article reviews the progress of exosome applications in stroke treatment. It aims to elucidate the significant potential value of exosomes in stroke therapy and provide a reference for their clinical translation. At present, many studies on exosome-based therapies for stroke are actively underway. Regarding preclinical research, exosomes, as bioactive substances with diverse sources, currently favor stem cells as their origin. Due to their high plasticity, exosomes can be effectively modified through various physical, chemical, and genetic engineering methods to enhance their efficacy. In animal models of stroke, exosome therapy can reduce neuroinflammatory responses, alleviate oxidative stress damage, and inhibit programmed cell death. Additionally, exosomes can promote angiogenesis, repair and regenerate damaged white matter fiber bundles, and facilitate the migration and differentiation of neural stem cells, aiding the repair process. We also summarize new directions for the application of exosomes, specifically the exosome intervention through the ventricular-meningeal lymphatic system. The review findings suggest that the treatment paradigm for stroke is poised for transformation.

Extracellular vesicles from adipose-derived stromal/stem cells reprogram dendritic cells to alleviate rat TMJOA by transferring mitochondria

Temporomandibular joint osteoarthritis (TMJOA) urgently needs regenerative therapies due to the limited effects of traditional treatments. Mesenchymal stem cell-derived extracellular vesicles (MSC-EVs) are considered a potent alternative for MSC therapy for the treatment of TMJOA. However, the specific mechanisms remain inadequately investigated. In this study, we explored how EVs from adipose-derived stromal/stem cells (ASCs) influence the TMJOA model triggered by Complete Freund's Adjuvant in rats and their impact on the state of dendritic cells (DCs) under pathological conditions. Subsequently, we conducted transcriptomic and metabolomic analyses to elucidate the specific mechanisms by which EVs affect DCs. Mechanistically, we demonstrate that EVs transferred functional mitochondria to DCs, which reverses their metabolic states. The internalized functional mitochondria from EVs activate the MAPK/ERK1/2/FoxO1/autophagy pathway, which causes the metabolic reprogramming of DCs and facilitates the achievement of therapeutic effects. These findings provide a mechanistic rationale for utilizing ASCs-EVs as cell-free alternatives to MSC transplantation in TMJOA therapy.

From powerhouse to modulator: regulating immune system responses through intracellular mitochondrial transfer

Mitochondria are traditionally known as the cells' powerhouses; however, their roles go far beyond energy suppliers. They are involved in intracellular signaling and thus play a crucial role in shaping cells' destiny and functionality, including immune cells. Mitochondria can be actively exchanged between immune and non-immune cells via mechanisms such as nanotubes and extracellular vesicles. The mitochondria transfer from immune cells to different cells is associated with physiological and pathological processes, including inflammatory disorders, cardiovascular diseases, diabetes, and cancer. On the other hand, mitochondrial transfer from mesenchymal stem cells, bone marrow-derived stem cells, and adipocytes to immune cells significantly affects their functions. Mitochondrial transfer can prevent exhaustion/senescence in immune cells through intracellular signaling pathways and metabolic reprogramming. Thus, it is emerging as a promising therapeutic strategy for immune system diseases, especially those involving inflammation and autoimmune components. Transferring healthy mitochondria into damaged or dysfunctional cells can restore mitochondrial function, which is crucial for cellular energy production, immune regulation, and inflammation control. Also, mitochondrial transfer may enhance the potential of current therapeutic immune cell-based therapies such as CAR-T cell 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.

Mesenchymal stem cell-mediated mitochondrial transfer regulates the fate of B lymphocytes

BACKGROUND

Mitochondrial transfer is becoming recognized as an important immunomodulatory mechanism used by mesenchymal stem cells (MSCs) to influence immune cells. While effects on T cells and macrophages have been documented, the influence on B cells remains unexplored. This study investigates the modulation of B lymphocyte fate by MSC-mediated mitochondrial transfer.

METHODS

MSCs labelled with MitoTracker dyes or derived from mito::mKate2 transgenic mice were co-cultured with splenocytes. Flow cytometry assessed mitochondrial transfer, reactive oxygen species (ROS) levels, apoptosis and mitophagy. Glucose uptake was measured using the 2-NBDG assay. RNA sequencing analysed gene expression changes in CD19+ mitochondria recipients and nonrecipients. Pathway analysis identified affected processes. In an LPS-induced inflammation model, mito::mKate2 MSCs were administered, and B cells from different organs were analysed for mitochondrial uptake and phenotypic changes. MSC-derived mitochondria were also isolated to confirm uptake by FACS-sorted CD19+ cells.

RESULTS

MSCs transferred mitochondria to CD19+ cells, though less than to other immune cells. Transfer correlated with ROS levels and mitophagy induction. Mitochondria were preferentially acquired by activated B cells, as indicated by increased CD69 expression and glycolytic activity. Bidirectional transfer occurred, with immune cells exchanging dysfunctional mitochondria for functional ones. CD19+ recipients exhibited increased viability, proliferation and altered gene expression, with upregulated cell division genes and downregulated antigen presentation genes. In vivo, mitochondrial acquisition reduced B cell activation and inflammatory cytokine production. Pre-sorted B cells also acquired isolated mitochondria, exhibiting a similar anti-inflammatory phenotype.

CONCLUSIONS

These findings highlight mitochondrial trafficking as a key MSC-immune cell interaction mechanism with immunomodulatory therapeutic potential.

Rekindling Vision: Innovative Strategies for Treating Retinal Degeneration

Retinal degeneration, characterized by the progressive loss of photoreceptors, retinal pigment epithelium cells, and/or ganglion cells, is a leading cause of vision impairment. These diseases are generally classified as inherited (e.g., retinitis pigmentosa, Stargardt disease) or acquired (e.g., age-related macular degeneration, diabetic retinopathy, glaucoma) ocular disorders that can lead to blindness. Available treatment options focus on managing symptoms or slowing disease progression and do not address the underlying causes of these diseases. However, recent advancements in regenerative medicine offer alternative solutions for repairing or protecting degenerated retinal tissue. Stem and progenitor cell therapies have shown great potential to differentiate into various retinal cell types and can be combined with gene editing, extracellular vesicles and exosomes, and bioactive molecules to modulate degenerative cellular pathways. Additionally, gene therapy and neuroprotective molecules play a crucial role in enhancing the efficacy of regenerative approaches. These innovative strategies hold the potential to halt the progression of retinal degenerative disorders, repair or replace damaged cells, and improve visual function, ultimately leading to a better quality of life for those affected.

Advances in clinical translation of stem cell-based therapy in neurological diseases

Stem cell-based therapies have raised considerable interest to develop regenerative treatment for neurological disorders with high disability. In this review, we focus on recent preclinical and clinical evidence of stem cell therapy in the treatment of degenerative neurological diseases and discuss different cell types, delivery routes and biodistribution of stem cell therapy. In addition, recent advances of mechanistic insights of stem cell therapy, including functional replacement by exogenous cells, immunomodulation and paracrine effects of stem cell therapies are also demonstrated. Finally, we also highlight the adjunction approaches that has been implemented to augment their reparative function, survival and migration to target specific tissue, including stem cell preconditioning, genetical engineering, co-transplantation and combined therapy.

Mitochondria Isolated From Bone Mesenchymal Stem Cells Restrain Muscle Disuse Atrophy and Fatty Infiltration After Rotator Cuff Tears

BACKGROUND

Rotator cuff tears (RCTs) commonly lead to muscle atrophy, fibrosis, and fatty infiltration, complicating treatment.

PURPOSE

To investigate the use of mitochondria isolated from bone mesenchymal stem cells (BMSC-Mito) for mitigating complications after RCT, focusing on muscle protection.

STUDY DESIGN

Controlled laboratory study.

METHODS

RCTs were induced by transecting the tendons of the supraspinatus and infraspinatus in Sprague-Dawley rats. In vivo, 90 rats were randomized into 3 groups: sham (no intervention), RCTs treated with BMSC-Mito, and RCTs treated with phosphate-buffered saline. After 6 weeks of intramuscular injections of BMSC-Mito or phosphate-buffered saline, supraspinatus muscles were harvested for analysis. Evaluations included wet muscle weight, muscle fiber cross-sectional area, fibrosis, fatty infiltration, slow-fast myofiber types and muscle biomechanics, capillary density, mitochondria respiratory chain complex activity, adenosine triphosphate (ATP) concentration, oxidative stress, and mitochondrial ultrastructure. In vitro experiments utilized primary rat skeletal muscle cells pretreated with rhodamine 6G to induce mitochondrial dysfunction, assessing the effects of BMSC-Mito on cell viability, mitochondrial membrane potential, and oxidative stress levels.

RESULTS

BMSC-Mito can be effectively transplanted into muscles and integrated into the local mitochondrial network. After RCT, the supraspinatus showed significant mass loss, reduced fiber cross-sectional area, fatty infiltration, and a shift from slow to fast myofiber types, which negatively affected muscle biomechanics. These changes were reversed by BMSC-Mito. BMSC-Mito also preserved vascularity (CD31 and α-SMA) impaired by RCT. Additionally, BMSC-Mito notably improved disuse-induced mitochondrial changes, leading to increased mitochondrial number and COX IV expression; furthermore, BMSC-Mito protected mitochondria morphology and enhanced cytosolic superoxide dismutase activity. This treatment also improved mitochondria respiratory chain complex activity and ATP concentration, reducing oxidative stress. In vitro, BMSC-Mito treatment effectively maintained the mitochondrial membrane potential of skeletal muscle cells, improved cell viability, and restored its mitochondrial function and ATP levels.

CONCLUSION

These findings suggest that BMSC-Mito might play a role in preventing muscle atrophy and fatty infiltration after RCT through the protection of mitochondrial function and the promotion of angiogenesis.

CLINICAL RELEVANCE

BMSC-Mito present a promising therapeutic approach for addressing rotator cuff muscle degeneration.

Human umbilical cord-derived mesenchymal stem cells attenuate liver fibrosis by inhibiting hepatocyte ferroptosis through mitochondrial transfer

Liver fibrosis is a reversible dynamic pathological process induced by chronic liver injury. Without intervention, liver fibrosis can progress to become cirrhosis, liver failure, or hepatocellular carcinoma, thus posing a high global health burden. Therefore, effective therapies for liver fibrosis are urgently required. Although transplantation of mesenchymal stem cells (MSCs) has significant value as a treatment strategy for liver damage, the underlying mechanisms remain unclear. Chronic liver injury progression is significantly influenced by hepatocyte ferroptosis, and targeting ferroptosis is emerging as a potential treatment strategy for liver fibrosis. Here, we showed that the infusion of human umbilical cord-derived MSCs (hUC-MSCs) alleviated TAA-induced liver fibrosis, improved liver functionality, and decreased ferroptosis in mice. hUC-MSCs inhibit ferroptosis-related mitochondrial damage and lipid peroxidation in AML12 cells in vitro. Mechanistically, under oxidative stress, hUC-MSCs transfer healthy mitochondria to damaged hepatocytes through tunneling nanotubes (TNTs). Cytochalasin D (CytoD), an inhibitor of TNT formation, abrogated the protective effects of hUC-MSCs against ferroptosis. This research emphasizes the ability of hUC-MSCs to serve as a promising treatment for liver fibrosis via mitochondrial transfer through TNTs.

Mitochondria-Rich Extracellular Vesicles From Bone Marrow Stem Cells Mitigate Muscle Degeneration in Rotator Cuff Tears in a Rat Model Through Macrophage M2 Phenotype Conversion

PURPOSE

To investigate the protective effects of extracellular vesicles derived from bone marrow stem cells (BMSC-EVs) on muscle degeneration in a rat model of rotator cuff tendon and suprascapular nerve (SSN) transection (termed the RCT-SSN model), focusing on mitochondrial transfer.

METHODS

The EVs were identified and characterized. The RCT-SSN model was established by transecting the supraspinatus, infraspinatus tendons, and suprascapular nerve. Ninety-six rats were divided into 4 groups (n = 24 each): sham surgery, RCT-SSN treated with BMSC-EVs, RCT-SSN treated with EVs from rhodamine 6G-pretreated BMSCs (Rho-EVs), or phosphate-buffered saline. Intramuscular injections were administered every 2 weeks. After 12 weeks, supraspinatus muscles were analyzed for atrophy, fibrosis, oxidative stress, macrophage phenotypes, serum cytokines, and mitochondrial characteristics. In vitro experiments included EVs tracking in macrophages, macrophage phenotype characterization, and inflammatory cytokine profiling.

RESULTS

BMSC-EVs and Rho-EVs displayed similar morphology, but only BMSC-EVs contained functional mitochondria. BMSC-EVs significantly reduced muscle weight loss (0.047 ± 0.010% vs 0.145 ± 0.013%, P < .001), increased muscle fiber cross-sectional area (2037 ± 231.9 μm2 vs 527.9 ± 92.01 μm2, P < .001), and decreased fibrosis (12.09 ± 3.31% vs 25.69 ± 4.84%, P < .001) compared with phosphate-buffered saline. BMSC-EVs enhanced superoxide dismutase activity (93.3 ± 11.8 U/mg protein vs 53.4 ± 8.0 U/mg protein, P < .001), improved mitochondrial function, density and structure, and induced an anti-inflammatory macrophage shift, suppressing proinflammatory cytokines in vitro and in vivo. Rho-EVs showed no such effects.

CONCLUSIONS

This study showed that transecting the supraspinatus, infraspinatus tendons, and suprascapular nerve in a rat model induced muscle degeneration and fibrosis. BMSC-EVs, but not Rho-EVs, mitigated these effects by promoting an anti-inflammatory macrophage phenotype and protecting mitochondrial function through mitochondrial transfer.

CLINICAL RELEVANCE

Mitochondrial transfer via BMSC-EVs may offer a therapeutic strategy to prevent muscle degeneration in patients with rotator cuff tear.

Mitochondria derived from Stem cells modulated the biological behavior of monocyte-macrophages and inhibited inflammatory bone resorption

BACKGROUND

The transfer of mitochondria from stem cells effectively attenuates the viability of inflammatory cells. However, there is a paucity of research supporting the inhibitory effect of stem cells on inflammatory bone resorption through mitochondrial transfer.

METHODS

Mouse bone resorption models were established to investigate the impact of stem cell-derived mitochondria. Stem cells, stem cell-derived mitochondria and exosomes were injected into the animal models for experimental research. Healthy mice and mice with bone resorption were included as the control groups. The mitochondrial transfer and bone resorption of mice calvaria were evaluated by immunofluorescence, gross morphology, micro-computed tomography (micro-CT), immunohistochemical staining. Monocyte-macrophages were incubated with stem cell-derived mitochondria as experimental group. Monocyte-macrophages and activated monocyte-macrophages cultured separately served as the control groups. The mitochondrial transfer and biological behavior of monocyte-macrophages were evaluated by immunofluorescence, enzyme-linked immunosorbent assay (ELISA), Multiskan FC, and histochemical staining.

RESULTS

Stem cell-derived mitochondria were successfully transferred to monocyte-macrophages. In vivo, local injection of stem cells, mitochondria, and exosomes effectively mitigated inflammatory cell infiltration, suppressed osteoclast maturation, and demonstrated a higher relative bone volume in mouse bone resorption models compared to the negative control group. In vitro, the co-incubation of mitochondria effectively suppressed the secretion of inflammatory cytokines, proliferation, fusion, and osteoclastogenesis in monocyte-macrophages compared to the control groups.

CONCLUSIONS

The modulation of monocyte-macrophages biological behaviors by stem cells may occur through the transfer of mitochondria, thereby mitigating inflammatory bone resorption.

Macrophage-derived mitochondria-rich extracellular vesicles aggravate bone loss in periodontitis by disrupting the mitochondrial dynamics of BMSCs

BACKGROUND

Periodontitis is the leading cause of tooth loss in adults due to progressive bone destruction, which is closely related to the dysfunction of bone mesenchymal stem cells (BMSCs). Existing evidence suggests that mitochondrial disorders are associated with periodontitis. However, whether mitochondrial dysregulation contributes to the osteogenic impairment of BMSCs and the underlying mechanisms remain unclear. Macrophages have been shown to communicate extensively with BMSCs in periodontitis. Recent studies have reported a novel manner of cellular communication in which mitochondria-rich extracellular vesicles（MEVs） transfer mitochondria from parent cells to recipient cells, playing a role in both physiological and pathological conditions. Therefore, we aimed to investigate the role of MEVs in orchestrating the crosstalk between macrophages and BMSCs in periodontitis to formulate management strategies for bone loss.

RESULTS

Our results revealed that macrophages underwent significant mitochondrial dysfunction and inflammation in periodontitis and that MEVs derived from these macrophages played a role in alveolar bone destruction. Furthermore, cell imaging showed that inflammatory macrophages packaged numerous damaged mitochondria into MEVs, and the entry of these impaired mitochondria into BMSCs disrupted mitochondrial dynamics and hindered donut-shaped mitochondria formation, leading to osteogenic dysfunction. Proteomic analysis revealed that the proteins enriched in macrophage-derived MEVs were largely related to mitochondria and the formation and transport of vesicles. Additionally, we found that MEVs from macrophages significantly increased lipocalin 2 (LCN2) in BMSCs in periodontitis and that LCN2 perturbed mitochondrial morphological changes in BMSCs by inducing the degradation of OMA1 and accumulation of OPA1, resulting in osteogenesis impairment in BMSCs. Inhibition of LCN2 rescued the osteogenic dysfunction of BMSCs and alveolar bone loss in periodontitis.

CONCLUSIONS

The transfer of mitochondria to BMSCs via MEVs exacerbates alveolar bone resorption through LCN2/OMA1/OPA1 signaling in periodontitis. Inhibition of LCN2 alleviates inflammatory bone loss, suggesting a promising therapeutic strategy for periodontitis.

Enhanced mitochondrial function and delivery from adipose-derived stem cell spheres via the EZH2-H3K27me3-PPARγ pathway for advanced therapy

BACKGROUND

Microenvironmental alterations induce significant genetic and epigenetic changes in stem cells. Mitochondria, essential for regenerative capabilities, provide the necessary energy for stem cell function. However, the specific roles of histone modifications and mitochondrial dynamics in human adipose-derived stem cells (ASCs) during morphological transformations remain poorly understood. In this study, we aim to elucidate the mechanisms by which ASC sphere formation enhances mitochondrial function, delivery, and rescue efficiency.

METHODS

ASCs were cultured on chitosan nano-deposited surfaces to form 3D spheres. Mitochondrial activity and ATP production were assessed using MitoTracker staining, Seahorse XF analysis, and ATP luminescence assays. Single-cell RNA sequencing, followed by Ingenuity Pathway Analysis (IPA), was conducted to uncover key regulatory pathways, which were validated through molecular techniques. Pathway involvement was confirmed using epigenetic inhibitors or PPARγ-modulating drugs. Mitochondrial structural integrity and delivery efficiency were evaluated after isolation.

RESULTS

Chitosan-induced ASC spheres exhibited unique compact mitochondrial morphology, characterized by condensed cristae, enhanced mitochondrial activity, and increased ATP production through oxidative phosphorylation. High expressions of mitochondrial complex I genes and elevated levels of mitochondrial complex proteins were observed without an increase in reactive oxygen species (ROS). Epigenetic modification of H3K27me3 and PPARγ involvement were discovered and confirmed by inhibiting H3K27me3 with the specific EZH2 inhibitor GSK126 and by adding the PPARγ agonist Rosiglitazone (RSG). Isolated mitochondria from ASC spheres showed improved structural stability and delivery efficiency, suppressed the of inflammatory cytokines in LPS- and TNFα-induced inflamed cells, and rescued cells from damage, thereby enhancing function and promoting recovery.

CONCLUSION

Enhancing mitochondrial ATP production via the EZH2-H3K27me3-PPARγ pathway offers an alternative strategy to conventional cell-based therapies. High-functional mitochondria and delivery efficiency show significant potential for regenerative medicine applications.

Apoptotic mesenchymal stem cells and their secreted apoptotic extracellular vesicles: therapeutic applications and mechanisms

Mesenchymal stem cells (MSCs), an accessible and less ethically controversial class of adult stem cells, have demonstrated significant efficacy in treating a wide range of diseases in both the preclinical and clinical phases. However, we do not yet have a clear understanding of the mechanisms by which MSCs exert their therapeutic effects in vivo. We found that the transplanted MSCs go an apoptotic fate within 24 h in vivo irrespective of the route of administration. Still, the short-term survival of MSCs do not affect their long-term therapeutic efficacy. An increasing number of studies have demonstrated that transplantation of apoptotic MSCs (ApoMSCs) show similar or even better efficacy than viable MSCs, including a variety of preclinical disease models such as inflammatory diseases, skin damage, bone damage, organ damage, etc. Although the exact mechanism has yet to be explored, recent studies have shown that transplanted MSCs undergo apoptosis in vivo and are phagocytosed by phagocytes, thereby exerting immunomodulatory effects. The apoptotic extracellular vesicles secreted by ApoMSCs (MSC-ApoEVs) play a significant role in promoting immunomodulation, endogenous stem cell regeneration, and angiogenesis due to their apoptotic properties and inheritance of molecular characteristics from their parental MSCs. On this basis, this review aims to deeply explore the therapeutic applications and mechanisms of ApoMSCs and their secretion of MSC-ApoEVs, as well as the challenges they face.

iPSC-derived exosomes as amphotericin B carriers: a promising approach to combat cryptococcal meningitis

Background

Cryptococcal meningitis (CM) is a significant global health issue, particularly affecting individuals with HIV. Amphotericin B (AmB) serves as the cornerstone treatment for CM; however, its clinical application is restricted due to limited penetration of the blood-brain barrier and associated nephrotoxicity.

Objective

This study investigates the use of exosomes derived from induced pluripotent stem cells (iPSC-Exos) as carriers for AmB in treating CM, aiming to enhance therapeutic efficacy and safety and reduce AmB toxicity.

Methods

Exosomes were extracted from iPSC culture supernatants using ultrafiltration and ultracentrifugation. Their morphology and size were analyzed using transmission electron microscopy (TEM) and nanoparticle flow cytometry (nFCM). Purity was confirmed by Western blotting for markers CD9, CD63, and TSG101. AmB was loaded into iPSC-Exos using a co-incubation method. The cytotoxicity of the iPSC-Exo/AmB complex was evaluated on HEK 293 T and RAW264.7 cells using the CCK-8 assay, while apoptosis was assessed using live/dead cell staining and flow cytometry. The hemolytic effects were tested using rabbit red blood cells. In a C57BL/6 J mouse model of cryptococcal infection, treatment groups (AmB, iPSC-Exo/AmB, and iPSC-Exo) were administered corresponding drugs, with blood and brain samples collected for analysis. The minimum inhibitory concentration (MIC) of iPSC-Exo/AmB and conventional AmB against Cryptococcus was determined.

Results

The iPSC-Exo/AmB complex exhibited reduced cytotoxicity in vitro and decreased AmB-induced renal and hepatic toxicity in vivo. Its MIC against Cryptococcus was over eight times lower than conventional AmB, significantly reducing fungal burden in the mouse brain and lowering serum inflammatory factors.

Conclusion

The iPSC-Exo/AmB complex is a promising therapeutic strategy that enhances AmB efficacy while reducing toxicity, offering new hope for treating CM and other refractory fungal infections of the central nervous system.

Mitochondria-rich extracellular vesicles derived from the culture supernatant of human synovial Fluid-derived mesenchymal stem cells Inhibited senescence of Stressed/inflammatory Licensed chondrocytes and Delayed Osteoarthritis progression

BACKGROUND

Mitochondrial dysfunction induces chondrocyte senescence, thereby precipitating articular cartilage (AC) degeneration in the pathogenesis of osteoarthritis (OA). Although the transfer of mitochondria from mesenchymal stem cells (MSCs) to host cells and their potential protective role have been demonstrated, whether MSCs can alleviate chondrocyte mitochondrial dysfunction or reverse OA progression remains unclear.

METHODS

A mitochondrial tracer was used to investigate the transfer of mitochondria-rich extracellular vesicles (MEV) derived from the culture supernatant of human synovial fluid-derived mesenchymal stem cells (hSF-MSCs). Human articular chondrocytes (hACs) impaired by oxidative stress co-incubated with MEV were used for experimental research in vitro. Healthy hACs and stressed hACs were cultured separately acting as the control groups. The MEV was injected into the OA rats' knee joint serving as experimental group. Healthy and OA rats were served as the control groups. Quantitative reverse transcription polymerase chain reaction (qRT-PCR), western blot (WB), enzyme- linked immunosorbent assay (ELISA), flow cytometry (FC), immunofluorescence (IF), fluorescence spectrophotometer (FS), immunohistochemistry (IHC) and other methods are used to analyze the effect of MEV on hACs and OA progression.

RESULTS

MEV derived from hSF-MSCs could transfer into hACs. Compared to the negative control group, co-incubation with MEV resulted in a significant down-regulation of oxidative stress markers and senescence-associated proteins in hACs, while improved mitochondrial function of hACs. Moreover, the MEV could traverse the dense interstitial layer and migrate towards the deeper cartilage, while intra-articular injection of MEV could effectively attenuate AC degeneration.

CONCLUSION

The transfer of MEV derived from hSF-MSCs represents a promising strategy for safeguarding AC, thereby offering a potential avenue and mechanism for the treatment of OA.

Engineering the Hydrophilic-Hydrophobic Interface of Polymeric Micelles by Cationic Blocks for Enhanced Chemotherapy

The cationic surface charge critically influences the biological functions and therapeutic outcomes of the cancer nanomedicines. However, the basic correlation between the cationic group categories and their therapeutic efficacy has not been elucidated. In this study, cationic polymeric nanoparticles with amino groups (primary, tertiary, and quaternary amines) as the single variable were leveraged to investigate the various effects of amino species for enhanced antitumor chemotherapy. The nanoparticles were constructed from a series of triblock polymers with varying cationic repeating units at the hydrophilic-hydrophobic interface. Our results suggested that quaternary ammonium outperforms its primary and tertiary counterparts in destroying mitochondrial membranes to induce apoptosis, penetrating deep inside the tumor tissue, and damaging tumor vasculatures. As a result, we were able to effectively inhibit tumor growth in mice by a quaternary ammonium conjugate without causing significant toxicity. Our work demonstrated that the chemical structures played vital roles in regulating their biological functions and provided valuable information for designing cationic drug delivery systems.

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.

Proposed Mechanisms of Cell Therapy for Alzheimer's Disease

Alzheimer's disease is a progressive neurodegenerative disorder characterized by mitochondria dysfunction, accumulation of beta-amyloid plaques, and hyperphosphorylated tau tangles in the brain leading to memory loss and cognitive deficits. There is currently no cure for this condition, but the potential of stem cells for the therapy of neurodegenerative pathologies is actively being researched. This review discusses preclinical and clinical studies that have used mouse models and human patients to investigate the use of novel types of stem cell treatment approaches. The findings provide valuable insights into the applications of stem cell-based therapies and include the use of neural, glial, mesenchymal, embryonic, and induced pluripotent stem cells. We cover current studies on stem cell replacement therapy where cells can functionally integrate into neural networks, replace damaged neurons, and strengthen impaired synaptic circuits in the brain. We address the paracrine action of stem cells acting via secreted factors to induce neuroregeneration and modify inflammatory responses. We focus on the neuroprotective functions of exosomes as well as their neurogenic and synaptogenic effects. We look into the shuttling of mitochondria through tunneling nanotubes that enables the transfer of healthy mitochondria by restoring the normal functioning of damaged cells, improving their metabolism, and reducing the level of apoptosis.

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.

Mechanisms Regulating Mitochondrial Transfer in Human Corneal Epithelial Cells

Purpose

The intraepithelial corneal nerves (ICNs) innervating the cornea are essential to corneal epithelial cell homeostasis. Rho-associated kinase (ROCK) inhibitors (RIs) have been reported to play roles in neuron survival after injury and in mitochondrial transfer between corneal epithelial cells. In this study, the mechanisms human corneal limbal epithelial (HCLE) cells use to control intercellular mitochondrial transfer are assessed.

Methods

Mitotracker and AAV1 mitotag eGFPmCherry were used to allow us to study mitochondrial transfer between HCLE cells and neurons in co-cultures and in HCLE cultures. A mitochondrial transfer assay was developed using HCLE cells to quantify the impact of cell stress and inhibition of phagocytosis, gap junctions, and ROCK on mitochondrial transfer, cell adhesion, migration, matrix deposition, and mitochondrial content.

Results

Bidirectional mitochondrial transfer occurs between HCLE cells and neurons. Mitochondrial transfer among HCLE cells is inhibited when gap junction function is reduced and enhanced by acid stress and by inhibition of either phagocytosis or ROCK. Media conditioned by RI-treated cells stimulates cell adhesion and mitochondrial transfer.

Conclusions

Maximal mitochondrial transfer takes place when gap junctions are functional, when ROCK and phagocytosis are inhibited, and when cells are stressed by low pH media. Treatments that reduce mitochondrial content increase HCLE cell mitochondrial transfer. ROCK inhibition in co-cultures causes the release and adhesion of mitochondria to substrates where they can be engulfed by migrating HCLE cells and growing axons and their growth cones.

Promotion of osteochondral repair through immune microenvironment regulation and activation of endogenous chondrogenesis via the release of apoptotic vesicles from donor MSCs

Utilizing transplanted human umbilical cord mesenchymal stem cells (HUMSCs) for cartilage defects yielded advanced tissue regeneration, but the underlying mechanism remain elucidated. Early after HUMSCs delivery to the defects, we observed substantial apoptosis. The released apoptotic vesicles (apoVs) of HUMSCs promoted cartilage regeneration by alleviating the chondro-immune microenvironment. ApoVs triggered M2 polarization in macrophages while simultaneously facilitating the chondrogenic differentiation of endogenous MSCs. Mechanistically, in macrophages, miR-100-5p delivered by apoVs activated the MAPK/ERK signaling pathway to promote M2 polarization. In MSCs, let-7i-5p delivered by apoVs promoted chondrogenic differentiation by targeting the eEF2K/p38 MAPK axis. Consequently, a cell-free cartilage regeneration strategy using apoVs combined with a decellularized cartilage extracellular matrix (DCM) scaffold effectively promoted the regeneration of osteochondral defects. Overall, new mechanisms of cartilage regeneration by transplanted MSCs were unconcealed in this study. Moreover, we provided a novel experimental basis for cell-free tissue engineering-based cartilage regeneration utilizing apoVs.

Mitochondrial transplantation: a promising strategy for treating degenerative joint diseases

The prevalence of age-related degenerative joint diseases, particularly intervertebral disc degeneration and osteoarthritis, is increasing, thereby posing significant challenges for the elderly population. Mitochondrial dysfunction is a critical factor in the etiology and progression of these disorders. Therapeutic interventions that incorporate mitochondrial transplantation exhibit considerable promise by increasing mitochondrial numbers and improving their functionality. Existing evidence suggests that exogenous mitochondrial therapy improves clinical outcomes for patients with degenerative joint diseases. This review elucidates the mitochondrial abnormalities associated with degenerative joint diseases and examines the mechanisms of mitochondrial intercellular transfer and artificial mitochondrial transplantation. Furthermore, therapeutic strategies for mitochondrial transplantation in degenerative joint diseases are synthesized, and the concept of engineered mitochondrial transplantation is proposed.

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.

Integrating Mitochondrial Biology into Innovative Cell Therapies for Neurodegenerative Diseases

The role of mitochondria in neurodegenerative diseases is crucial, and recent developments have highlighted its significance in cell therapy. Mitochondrial dysfunction has been implicated in various neurodegenerative disorders, including Alzheimer's, Parkinson's, amyotrophic lateral sclerosis, and Huntington's diseases. Understanding the impact of mitochondrial biology on these conditions can provide valuable insights for developing targeted cell therapies. This mini-review refocuses on mitochondria and emphasizes the potential of therapies leveraging mesenchymal stem cells, embryonic stem cells, induced pluripotent stem cells, stem cell-derived secretions, and extracellular vesicles. Mesenchymal stem cell-mediated mitochondria transfer is highlighted for restoring mitochondrial health in cells with dysfunctional mitochondria. Additionally, attention is paid to gene-editing techniques such as mito-CRISPR, mitoTALENs, mito-ZNFs, and DdCBEs to ensure the safety and efficacy of stem cell treatments. Challenges and future directions are also discussed, including the possible tumorigenic effects of stem cells, off-target effects, disease targeting, immune rejection, and ethical issues.

Horizontal mitochondrial transfer as a novel bioenergetic tool for mesenchymal stromal/stem cells: molecular mechanisms and therapeutic potential in a variety of diseases

Intercellular mitochondrial transfer (MT) is a newly discovered form of cell-to-cell signalling involving the active incorporation of healthy mitochondria into stressed/injured recipient cells, contributing to the restoration of bioenergetic profile and cell viability, reduction of inflammatory processes and normalisation of calcium dynamics. Recent evidence has shown that MT can occur through multiple cellular structures and mechanisms: tunneling nanotubes (TNTs), via gap junctions (GJs), mediated by extracellular vesicles (EVs) and other mechanisms (cell fusion, mitochondrial extrusion and migrasome-mediated mitocytosis) and in different contexts, such as under physiological (tissue homeostasis and stemness maintenance) and pathological conditions (hypoxia, inflammation and cancer). As Mesenchimal Stromal/ Stem Cells (MSC)-mediated MT has emerged as a critical regulatory and restorative mechanism for cell and tissue regeneration and damage repair in recent years, its potential in stem cell therapy has received increasing attention. In particular, the potential therapeutic role of MSCs has been reported in several articles, suggesting that MSCs can enhance tissue repair after injury via MT and membrane vesicle release. For these reasons, in this review, we will discuss the different mechanisms of MSCs-mediated MT and therapeutic effects on different diseases such as neuronal, ischaemic, vascular and pulmonary diseases. Therefore, understanding the molecular and cellular mechanisms of MT and demonstrating its efficacy could be an important milestone that lays the foundation for future clinical trials.

Miro1 improves the exogenous engraftment efficiency and therapeutic potential of mitochondria transfer using Wharton's jelly mesenchymal stem cells

Mitochondria are important for maintaining cellular energy metabolism and regulating cellular senescence. Mitochondrial DNA (mtDNA) encodes subunits of the OXPHOS complexes which are essential for cellular respiration and energy production. Meanwhile, mtDNA variants have been associated with the pathogenesis of neurodegenerative diseases, including MELAS, for which no effective treatment has been developed. To alleviate the pathological conditions involved in mitochondrial disorders, mitochondria transfer therapy has shown promise. Wharton's jelly mesenchymal stem cells (WJMSCs) have been identified as suitable mitochondria donors for mitochondria-defective cells, wherein mitochondrial functions can be rescued. Miro1 participates in mitochondria trafficking by anchoring mitochondria to microtubules. In this study, we identified Miro1 over-expression as a factor that could help to enhance the efficiency of mitochondrial delivery. More specifically, we reveal that Miro1 over-expressed WJMSCs significantly improved intercellular communications, cell proliferation rates, and mitochondrial membrane potential, while restoring mitochondrial bioenergetics in mitochondria-defective fibroblasts. Furthermore, Miro1 over-expressed WJMSCs decreased rates of induced apoptosis and ROS production in MELAS fibroblasts; although, Miro1 over-expression did not rescue mtDNA mutation ratios nor mitochondrial biogenesis. This study presents a potentially novel therapeutic strategy for treating mitochondrial encephalomyopathy, lactic acidosis and stroke-like episodes (MELAS), and other diseases associated with dysfunctional mitochondria, while the pathophysiological relevance of our results should be further verified by animal models and clinical studies.

MSC-derived mitochondria promote axonal regeneration via Atf3 gene up-regulation by ROS induced DNA double strand breaks at transcription initiation region

BACKGROUND

The repair of peripheral nerve injury poses a clinical challenge, necessitating further investigation into novel therapeutic approaches. In recent years, bone marrow mesenchymal stromal cell (MSC)-derived mitochondrial transfer has emerged as a promising therapy for cellular injury, with reported applications in central nerve injury. However, its potential therapeutic effect on peripheral nerve injury remains unclear.

METHODS

We established a mouse sciatic nerve crush injury model. Mitochondria extracted from MSCs were intraneurally injected into the injured sciatic nerves. Axonal regeneration was observed through whole-mount nerve imaging. The dorsal root ganglions (DRGs) corresponding to the injured nerve were harvested to test the gene expression, reactive oxygen species (ROS) levels, as well as the degree and location of DNA double strand breaks (DSBs).

RESULTS

The in vivo experiments showed that the mitochondrial injection therapy effectively promoted axon regeneration in injured sciatic nerves. Four days after injection of fluorescently labeled mitochondria into the injured nerves, fluorescently labeled mitochondria were detected in the corresponding DRGs. RNA-seq and qPCR results showed that the mitochondrial injection therapy enhanced the expression of Atf3 and other regeneration-associated genes in DRG neurons. Knocking down of Atf3 in DRGs by siRNA could diminish the therapeutic effect of mitochondrial injection. Subsequent experiments showed that mitochondrial injection therapy could increase the levels of ROS and DSBs in injury-associated DRG neurons, with this increase being correlated with Atf3 expression. ChIP and Co-IP experiments revealed an elevation of DSB levels within the transcription initiation region of the Atf3 gene following mitochondrial injection therapy, while also demonstrating a spatial proximity between mitochondria-induced DSBs and CTCF binding sites.

CONCLUSION

These findings suggest that MSC-derived mitochondria injected into the injured nerves can be retrogradely transferred to DRG neuron somas via axoplasmic transport, and increase the DSBs at the transcription initiation regions of the Atf3 gene through ROS accumulation, which rapidly release the CTCF-mediated topological constraints on chromatin interactions. This process may enhance spatial interactions between the Atf3 promoter and enhancer, ultimately promoting Atf3 expression. The up-regulation of Atf3 induced by mitochondria further promotes the expression of downstream regeneration-associated genes and facilitates axon regeneration.

Signaling crosstalk between mesenchymal stem cells and tumor cells: Implications for tumor suppression or progression

Mesenchymal stem cells (MSCs) have been extensively used in various therapeutic applications over the last two decades, particularly in regenerative medicine and cancer treatment. MSCs have the ability to differentiate into mesodermal and non-mesodermal lineages, which makes them a popular choice in tissue engineering and regenerative medicine. Studies have shown that MSCs have inherent tumor-suppressive properties and can affect the behavior of multiple cells contributing to tumor development. Additionally, MSCs possess a tumor tropism property and have a hypoimmune nature. The intrinsic features of MSCs along with their potential to undergo genetic manipulation and be loaded with various anticancer therapeutics have motivated researchers to use them in different cancer therapy approaches without considering their complex dynamic biological aspects. However, despite their desirable features, several reports have shown that MSCs possess tumor-supportive properties. These contradictory results signify the sophisticated nature of MSCs and warn against the potential therapeutic applications of MSCs. Therefore, researchers should meticulously consider the biological properties of MSCs in preclinical and clinical studies to avoid any undesirable outcomes. This manuscript reviews preclinical studies on MSCs and cancer from the last two decades, discusses how MSC properties affect tumor progression and explains the mechanisms behind tumor suppressive and supportive functions. It also highlights critical cellular pathways that could be targeted in future studies to improve the safety and effectiveness of MSC-based therapies for cancer treatment. The insights obtained from this study will pave the way for further clinical research on MSCs and development of more effective cancer treatments.

Therapeutic and immunomodulatory potentials of mesenchymal stromal/stem cells and immune checkpoints related molecules

Mesenchymal stromal/stem cells (MSCs) are used in many studies due to their therapeutic potential, including their differentiative ability and immunomodulatory properties. These cells perform their therapeutic functions by using various mechanisms, such as the production of anti-inflammatory cytokines, growth factors, direct cell-to-cell contact, extracellular vesicles (EVs) production, and mitochondrial transfer. However, mechanisms related to immune checkpoints (ICPs) and their effect on the immunomodulatory ability of MSCs are less discussed. The main function of ICPs is to prevent the initiation of unwanted responses and to regulate the immune system responses to maintain the homeostasis of these responses. ICPs are produced by various types of immune system regulatory cells, and defects in their expression and function may be associated with excessive responses that can ultimately lead to autoimmunity. Also, by expressing different types of ICPs and their ligands (ICPLs), tumor cells prevent the formation and durability of immune responses, which leads to tumors' immune escape. ICPs and ICPLs can be produced by MSCs and affect immune cell responses both through their secretion into the microenvironment or direct cell-to-cell interaction. Pre-treatment of MSCs in inflammatory conditions leads to an increase in their therapeutic potential. In addition to the effect that inflammatory environments have on the production of anti-inflammatory cytokines by MSCs, they can increase the expression of various types of ICPLs. In this review, we discuss different types of ICPLs and ICPs expressed by MSCs and their effect on their immunomodulatory and therapeutic potential.

The Role of Mitochondrial Quality Control in Chronic Obstructive Pulmonary Disease

Chronic obstructive pulmonary disease (COPD) is a major cause of morbidity, mortality, and health care use worldwide with heterogeneous pathogenesis. Mitochondria, the powerhouses of cells responsible for oxidative phosphorylation and energy production, play essential roles in intracellular material metabolism, natural immunity, and cell death regulation. Therefore, it is crucial to address the urgent need for fine-tuning the regulation of mitochondrial quality to combat COPD effectively. Mitochondrial quality control (MQC) mainly refers to the selective removal of damaged or aging mitochondria and the generation of new mitochondria, which involves mitochondrial biogenesis, mitochondrial dynamics, mitophagy, etc. Mounting evidence suggests that mitochondrial dysfunction is a crucial contributor to the development and progression of COPD. This article mainly reviews the effects of MQC on COPD as well as their specific regulatory mechanisms. Finally, the therapeutic approaches of COPD via MQC are also illustrated.

Engineered stem cell-based strategy: A new paradigm of next-generation stem cell product in regenerative medicine

Stem cells have garnered significant attention in regenerative medicine owing to their abilities of multi-directional differentiation and self-renewal. Despite these encouraging results, the market for stem cell products yields limited, which is largely due to the challenges faced to the safety and viability of stem cells in vivo. Besides, the fate of cells re-infusion into the body unknown is also a major obstacle to stem cell therapy. Actually, both the functional protection and the fate tracking of stem cells are essential in tissue homeostasis, repair, and regeneration. Recent studies have utilized cell engineering techniques to modify stem cells for enhancing their treatment efficiency or imparting them with novel biological capabilities, in which advances demonstrate the immense potential of engineered cell therapy. In this review, we proposed that the "engineered stem cells" are expected to represent the next generation of stem cell therapies and reviewed recent progress in this area. We also discussed potential applications of engineered stem cells and highlighted the most common challenges that must be addressed. Overall, this review has important guiding significance for the future design of new paradigms of stem cell products to improve their therapeutic efficacy.

Body fluid-derived stem cells - an untapped stem cell source in genitourinary regeneration

Somatic stem cells have been obtained from solid organs and tissues, including the bone marrow, placenta, corneal stroma, periosteum, adipose tissue, dental pulp and skeletal muscle. These solid tissue-derived stem cells are often used for tissue repair, disease modelling and new drug development. In the past two decades, stem cells have also been identified in various body fluids, including urine, peripheral blood, umbilical cord blood, amniotic fluid, synovial fluid, breastmilk and menstrual blood. These body fluid-derived stem cells (BFSCs) have stemness properties comparable to those of other adult stem cells and, similarly to tissue-derived stem cells, show cell surface markers, multi-differentiation potential and immunomodulatory effects. However, BFSCs are more easily accessible through non-invasive or minimally invasive approaches than solid tissue-derived stem cells and can be isolated without enzymatic tissue digestion. Additionally, BFSCs have shown good versatility in repairing genitourinary abnormalities in preclinical models through direct differentiation or paracrine mechanisms such as pro-angiogenic, anti-apoptotic, antifibrotic, anti-oxidant and anti-inflammatory effects. However, optimization of protocols is needed to improve the efficacy and safety of BFSC therapy before therapeutic translation.

Cancer-associated mesenchymal stem/stromal cells: role in progression and potential targets for therapeutic approaches

Malignancies contain a relatively small number of Mesenchymal stem/stromal cells (MSCs), constituting a crucial tumor microenvironment (TME) component. These cells comprise approximately 0.01-5% of the total TME cell population. MSC differentiation potential and their interaction with the tumor environment enable these cells to affect tumor cells' growth, immune evasion, metastasis, drug resistance, and angiogenesis. This type of MSC, known as cancer-associated mesenchymal stem/stromal cells (CA-MSCs (interacts with tumor/non-tumor cells in the TME and affects their function by producing cytokines, chemokines, and various growth factors to facilitate tumor cell migration, survival, proliferation, and tumor progression. Considering that the effect of different cells on each other in the TME is a multi-faceted relationship, it is essential to discover the role of these relationships for targeting in tumor therapy. Due to the immunomodulatory role and the tissue repair characteristic of MSCs, these cells can help tumor growth from different aspects. CA-MSCs indirectly suppress antitumor immune response through several mechanisms, including decreasing dendritic cells (DCs) antigen presentation potential, disrupting natural killer (NK) cell differentiation, inducing immunoinhibitory subsets like tumor-associated macrophages (TAMs) and Treg cells, and immune checkpoint expression to reduce effector T cell antitumor responses. Therefore, if these cells can be targeted for treatment so that their population decreases, we can hope for the treatment and improvement of the tumor conditions. Also, various studies show that CA-MSCs in the TME can affect other vital aspects of a tumor, including cell proliferation, drug resistance, angiogenesis, and tumor cell invasion and metastasis. In this review article, we will discuss in detail some of the mechanisms by which CA-MSCs suppress the innate and adaptive immune systems and other mechanisms related to tumor progression.

Therapeutic Effects of Mesenchymal Stromal Cells Require Mitochondrial Transfer and Quality Control

Due to their beneficial effects in an array of diseases, Mesenchymal Stromal Cells (MSCs) have been the focus of intense preclinical research and clinical implementation for decades. MSCs have multilineage differentiation capacity, support hematopoiesis, secrete pro-regenerative factors and exert immunoregulatory functions promoting homeostasis and the resolution of injury/inflammation. The main effects of MSCs include modulation of immune cells (macrophages, neutrophils, and lymphocytes), secretion of antimicrobial peptides, and transfer of mitochondria (Mt) to injured cells. These actions can be enhanced by priming (i.e., licensing) MSCs prior to exposure to deleterious microenvironments. Preclinical evidence suggests that MSCs can exert therapeutic effects in a variety of pathological states, including cardiac, respiratory, hepatic, renal, and neurological diseases. One of the key emerging beneficial actions of MSCs is the improvement of mitochondrial functions in the injured tissues by enhancing mitochondrial quality control (MQC). Recent advances in the understanding of cellular MQC, including mitochondrial biogenesis, mitophagy, fission, and fusion, helped uncover how MSCs enhance these processes. Specifically, MSCs have been suggested to regulate peroxisome proliferator-activated receptor-gamma coactivator 1 alpha (PGC1α)-dependent biogenesis, Parkin-dependent mitophagy, and Mitofusins (Mfn1/2) or Dynamin Related Protein-1 (Drp1)-mediated fission/fusion. In addition, previous studies also verified mitochondrial transfer from MSCs through tunneling nanotubes and via microvesicular transport. Combined, these effects improve mitochondrial functions, thereby contributing to the resolution of injury and inflammation. Thus, uncovering how MSCs affect MQC opens new therapeutic avenues for organ injury, and the transplantation of MSC-derived mitochondria to injured tissues might represent an attractive new therapeutic approach.

Targeting different phenotypes of macrophages: A potential strategy for natural products to treat inflammatory bone and joint diseases

BACKGROUND

Macrophages, a key class of immune cells, have a dual role in inflammatory responses, switching between anti-inflammatory M2 and pro-inflammatory M1 subtypes depending on the specific environment. Greater numbers of M1 macrophages correlate with increased production of inflammatory chemicals, decreased osteogenic potential, and eventually bone and joint disorders. Therefore, reversing M1 macrophages polarization is advantageous for lowering inflammatory factors. To better treat inflammatory bone disorders in the future, it may be helpful to gain insight into the specific mechanisms and natural products that modulate macrophage polarization.

OBJECTIVE

This review examines the impact of programmed cell death and different cells in the bone microenvironment on macrophage polarization, as well as the effects of natural products on the various phenotypes of macrophages, in order to suggest some possibilities for the treatment of inflammatory osteoarthritic disorders.

METHODS

Using 'macrophage polarization,' 'M1 macrophage' 'M2 macrophage' 'osteoporosis,' 'osteonecrosis of femoral head,' 'osteolysis,' 'gouty arthritis,' 'collagen-induced arthritis,' 'freund's adjuvant-induced arthritis,' 'adjuvant arthritis,' and 'rheumatoid arthritis' as search terms, the relevant literature was searched using the PubMed, the Cochrane Library and Web of Science databases.

RESULTS

Targeting macrophages through different signaling pathways has become a key mechanism for the treatment of inflammatory bone and joint diseases, including HIF-1α, NF-κB, AKT/mTOR, JAK1/2-STAT1, NF-κB, JNK, ERK, p-38α/β, p38/MAPK, PI3K/AKT, AMPK, AMPK/Sirt1, STAT TLR4/NF-κB, TLR4/NLRP3, NAMPT pathway, as well as the programmed cell death autophagy, pyroptosis and ERS.

CONCLUSION

As a result of a search of databases, we have summarized the available experimental and clinical evidence supporting herbal products as potential treatment agents for inflammatory osteoarthropathy. In this paper, we outline the various modulatory effects of natural substances targeting macrophages in various diseases, which may provide insight into drug options and directions for future clinical trials. In spite of this, more mechanistic studies on natural substances, as well as pharmacological, toxicological, and clinical studies are required.

Pancreatic cancer and exosomes: role in progression, diagnosis, monitoring, and treatment

Pancreatic cancer (PC) is one of the most dangerous diseases that threaten human life, and investigating the details affecting its progression or regression is particularly important. Exosomes are one of the derivatives produced from different cells, including tumor cells and other cells such as Tregs, M2 macrophages, and MDSCs, and can help tumor growth. These exosomes perform their actions by affecting the cells in the tumor microenvironment, such as pancreatic stellate cells (PSCs) that produce extracellular matrix (ECM) components and immune cells that are responsible for killing tumor cells. It has also been shown that pancreatic cancer cell (PCC)-derived exosomes at different stages carry molecules. Checking the presence of these molecules in the blood and other body fluids can help us in the early stage diagnosis and monitoring of PC. However, immune system cell-derived exosomes (IEXs) and mesenchymal stem cell (MSC)-derived exosomes can contribute to PC treatment. Immune cells produce exosomes as part of the mechanisms involved in the immune surveillance and tumor cell-killing phenomenon. Exosomes can be modified in such a way that their antitumor properties are enhanced. One of these methods is drug loading in exosomes, which can significantly increase the effectiveness of chemotherapy drugs. In general, exosomes form a complex intercellular communication network that plays a role in developing, progressing, diagnosing, monitoring, and treating pancreatic cancer.

Current perspectives on mesenchymal stromal cell therapy for graft versus host disease

Graft versus host disease (GvHD) is the clinical condition in which bone marrow-derived mesenchymal stromal cells (MSCs) have been most frequently studied. In this review, we summarize the experience from clinical trials that have paved the way to translation. While MSC-based therapy has shown an exceptional safety profile, identifying potency assays and disease biomarkers that reliably predict the capacity of a specific MSC batch to alleviate GvHD has been difficult. As GvHD diagnosis and staging are based solely on clinical criteria, individual patients recruited in the same clinical trial may have vastly different underlying biology, obscuring trial outcomes and making it difficult to determine the benefit of MSCs in subgroups of patients. An accumulating body of evidence indicates the importance of considering not only the cell product but also patient-specific biomarkers and/or immune characteristics in determining MSC responsiveness. A mode of action where intravascular MSC destruction is followed by monocyte-efferocytosis-mediated skewing of the immune repertoire in a permissive inflammatory environment would both explain why cell engraftment is irrelevant for MSC efficacy and stress the importance of biologic differences between responding and nonresponding patients. We recommend a combined analysis of clinical outcomes and both biomarkers of disease activity and MSC potency assays to identify patients with GvHD who are likely to benefit from MSC therapy.

Combinational administration of mesenchymal stem cell-derived exosomes and metformin reduces inflammatory responses in an in vitro model of insulin resistance in HepG2 cells

Diabetes is a highly common metabolic disorder in advanced societies. One of the causes of diabetes is insulin resistance, which is associated with a loss of sensitivity to insulin-sensitive cells. Insulin resistance develops in the body of a person prone to diabetes many years before diabetes development. Insulin resistance is associated with complications such as hyperglycemia, hyperlipidemia, and compensatory hyperinsulinemia and causes liver inflammation, which, if left untreated, can lead to cirrhosis, fibrosis, and even liver cancer. Metformin is the first line of treatment for patients with diabetes, which lowers blood sugar and increases insulin sensitivity by inhibiting gluconeogenesis in liver cells. The use of metformin has side effects, including a metallic taste in the mouth, vomiting, nausea, diarrhea, and upset stomach. For this reason, other treatments, along with metformin, are being developed. Considering the anti-inflammatory role of mesenchymal stem cells (MSCs) derived exosomes, their use seems to help improve liver tissue function and prevent damage caused by inflammation. This study investigated the anti-inflammatory effect of Wharton's jelly MSCs derived exosomes in combination with metformin in the HepG2 cells insulin resistance model induced by high glucose. This study showed that MSCs derived exosomes as an anti-inflammatory agent in combination with metformin could increase the therapeutic efficacy of metformin without needing to change metformin doses by decreasing inflammatory cytokines production, including IL-1, IL-6, and TNF-α and apoptosis in HepG2 cells.