Effective treatment of optic neuropathies by intraocular delivery of MSC-sEVs through augmenting the G-CSF-macrophage pathway.

Optic neuropathies, characterized by injury of retinal ganglion cell (RGC) axons of the optic nerve, cause incurable blindness worldwide. Mesenchymal stem cell-derived small extracellular vesicles (MSC-sEVs) represent a promising "cell-free" therapy for regenerative medicine; however, the therapeutic effect on neural restoration fluctuates, and the underlying mechanism is poorly understood. Here, we illustrated that intraocular administration of MSC-sEVs promoted both RGC survival and axon regeneration in an optic nerve crush mouse model. Mechanistically, MSC-sEVs primarily targeted retinal mural cells to release high levels of colony-stimulating factor 3 (G-CSF) that recruited a neural restorative population of Ly6Clow monocytes/monocyte-derived macrophages (Mo/MΦ). Intravitreal administration of G-CSF, a clinically proven agent for treating neutropenia, or donor Ly6Clow Mo/MΦ markedly improved neurological outcomes in vivo. Together, our data define a unique mechanism of MSC-sEV-induced G-CSF-to-Ly6Clow Mo/MΦ signaling in repairing optic nerve injury and highlight local delivery of MSC-sEVs, G-CSF, and Ly6Clow Mo/MΦ as therapeutic paradigms for the treatment of optic neuropathies.

Tibetan Mesenchymal Stem Cell-derived Exosomes Alleviate Pulmonary Vascular Remodeling in Hypoxic Pulmonary Hypertension Rats.

Hypoxic pulmonary hypertension (HPH) is characterized by progressive pulmonary vasoconstriction, vascular remodeling, and right ventricular hypertrophy, causing right heart failure. This study aimed to investigate the therapeutic effects of exosomes from Tibetan umbilical cord mesenchymal stem cells on HPH via the TGF-ß1/Smad2/3 pathway, comparing them with exosomes from Han Chinese individuals. An HPH rat model was established in vivo, and a hypoxia-induced injury in the rat pulmonary artery smooth muscle cells (rPASMCs) was simulated in vitro. Exosomes from human umbilical cord mesenchymal stem cells were administered to HPH model rats or added to cultured rPASMCs. The therapeutic effects of Tibetan-mesenchymal stem cell-derived exosomes (Tibetan-MSC-exo) and Han-mesenchymal stem cell-derived exosomes (Han-MSC-exo) on HPH were investigated through immunohistochemistry, Western blotting, EdU, and Transwell assays. The results showed that Tibetan-MSC-exo significantly attenuated pulmonary vascular remodeling and right ventricular hypertrophy in HPH rats compared with Han-MSC-exo. Tibetan-MSC-exo demonstrated better inhibition of hypoxia-induced rPASMCs proliferation and migration. Transcriptome sequencing revealed upregulated genes (Nbl1, Id2, Smad6, and Ltbp1) related to the TGFß pathway. Nbl1 knockdown enhanced hypoxia-induced rPASMCs proliferation and migration, reversing Tibetan-MSC-exo-induced downregulation of TGFß1 and p-Smad2/3. Furthermore, TGFß1 overexpression hindered the therapeutic effects of Tibetan-MSC-exo and Han-MSC-exo on hypoxic injury. These findings suggest that Tibetan-MSC-exo favors HPH treatment better than Han-MSC-exo, possibly through the modulation of the TGFß1/Smad2/3 pathway via Nbl1.

Bone marrow mesenchymal stem cell-derived exosomes effectively ameliorate the outcomes of rats with acute graft-versus-host disease.

Mesenchymal stem cells (MSCs) reveal multifaceted immunoregulatory properties, which can be applied for diverse refractory and recurrent disease treatment including acute graft-versus-host disease (aGVHD). Distinguishing from MSCs with considerable challenges before clinical application, MSCs-derived exosomes (MSC-Exos) are cell-free microvesicles with therapeutic ingredients and serve as advantageous alternatives for ameliorating the outcomes of aGVHD. MSC-Exos were enriched and identified by western blotting analysis, NanoSight, and transmission electron microscopy (TEM). Bone marrow-derived MSCs (denoted as MSCs) and exosomes (denoted as MSC-Exos) were infused into the aGVHD SD-Wister rat model via tail vein, and variations in general growth and survival of rats were observed. The level of inflammatory factors in serum was quantized by enzyme-linked immunosorbent assay (ELISA). The pathological conditions of the liver and intestine of rats were observed by frozen sectioning. The ratios of CD4+/CD8+ and Treg cell proportions in peripheral blood, together with the autophagy in the spleen and thymus, were analyzed by flow cytometry. After treatment with MSC-Exos, the survival time of aGVHD rats was prolonged, the clinical manifestations of aGVHD in rats were improved, whereas the pathological damage of aGVHD in the liver and intestine was reduced. According to ELISA, we found that MSC-Exos revealed ameliorative effect upon aGVHD inflammation (e.g., TNF-α, IL-2, INF-γ, IL-4, and TGF-ß) compared to the MSC group. After MSC-Exo treatment, the ratio of Treg cells in peripheral blood was increased, whereas the ratio of CD4+/CD8+ in peripheral blood and the autophagy in the spleen and thymus was decreased. MSC-Exos effectively suppressed the activation of immune cells and the manifestation of the inflammatory response in the aGVHD rat model. Our data would supply new references for MSC-Exo-based "cell-free" biotherapy for aGVHD in future.

Marrow mesenchymal stem cell mediates diabetic nephropathy progression via modulation of Smad2/3/WTAP/m6A/ENO1 axis.

Diabetic nephropathy (DN) is one of the common microvascular complications in diabetic patients. Marrow mesenchymal stem cells (MSCs) have attracted attention in DN therapy but the underlying mechanism remains unclear. Here, we show that MSC administration alleviates high glucose (HG)-induced human kidney tubular epithelial cell (HK-2 cell) injury and ameliorates renal injury in DN mice. We identify that Smad2/3 is responsible for MSCs-regulated DN progression. The activity of Smad2/3 was predominantly upregulated in HG-induced HK-2 cell and DN mice and suppressed with MSC administration. Activation of Smad2/3 via transforming growth factor-ß1 (TGF-ß1) administration abrogates the protective effect of MSCs on HG-induced HK-2 cell injury and renal injury of DN mice. Smad2/3 has been reported to interact with methyltransferase of N6-methyladenosine (m6A) complex and we found a methyltransferase, Wilms' tumor 1-associating protein (WTAP), is involved in MSCs-Smad2/3-regulated DN development. Moreover, WTAP overexpression abrogates the improvement of MSCs on HG-induced HK-2 cell injury and renal injury of DN mice. Subsequently, α-enolase (ENO1) is the downstream target of WTAP-mediated m6A modification and contributes to the MSCs-mediated regulation. Collectively, these findings reveal a molecular mechanism in DN progression and indicate that Smad2/3/WTAP/ENO1 may present a target for MSCs-mediated DN therapy.

Exercise to Mend Aged-tissue Crosstalk in Bone Targeting Osteoporosis & Osteoarthritis.

Aging induces alterations in bone structure and strength through a multitude of processes, exacerbating common aging- related diseases like osteoporosis and osteoarthritis. Cellular hallmarks of aging are examined, as related to bone and the marrow microenvironment, and ways in which these might contribute to a variety of age-related perturbations in osteoblasts, osteocytes, marrow adipocytes, chondrocytes, osteoclasts, and their respective progenitors. Cellular senescence, stem cell exhaustion, mitochondrial dysfunction, epigenetic and intracellular communication changes are central pathways and recognized as associated and potentially causal in aging. We focus on these in musculoskeletal system and highlight knowledge gaps in the literature regarding cellular and tissue crosstalk in bone, cartilage, and the bone marrow niche. While senolytics have been utilized to target aging pathways, here we propose non-pharmacologic, exercise-based interventions as prospective "senolytics" against aging effects on the skeleton. Increased bone mass and delayed onset or progression of osteoporosis and osteoarthritis are some of the recognized benefits of regular exercise across the lifespan. Further investigation is needed to delineate how cellular indicators of aging manifest in bone and the marrow niche and how altered cellular and tissue crosstalk impact disease progression, as well as consideration of exercise as a therapeutic modality, as a means to enhance discovery of bone-targeted therapies.

A 163-bp insertion in the Capana10g000198 encoding a MYB transcription factor causes male sterility in pepper (Capsicum annuum L.).

Male sterility provides an efficient approach for commercial exploitation of heterosis. Despite more than 20 genic male sterile (GMS) mutants documented in pepper (Capsicum annuum L.), only two causal genes have been successfully identified. Here, a novel spontaneous recessive GMS mutant, designated msc-3, is identified and characterized at both phenotypic and histological levels. Pollen abortion of msc-3 mutant may be due to the delayed tapetum degradation, leading to the non-degeneration of tetrads callosic wall. Then, a modified MutMap method and molecular marker linkage analysis were employed to fine mapping the msc-3 locus, which was delimited to the ~139.91-kb region harboring 10 annotated genes. Gene expression and structure variation analyses indicate the Capana10g000198, encoding a R2R3-MYB transcription factor, is the best candidate gene for the msc-3 locus. Expression profiling analysis shows the Capana10g000198 is an anther-specific gene, and a 163-bp insertion in the Capana10g000198 is highly correlated with the male sterile (MS) phenotype. Additionally, downregulation of Capana10g000198 in male fertile plants through virus-induced gene silencing resulted in male sterility. Finally, possible regulatory relationships of the msc-3 gene with the other two reported pepper GMS genes, msc-1 and msc-2, have been studied, and comparative transcriptome analysis reveals the expression of 16 GMS homologs are significantly downregulated in the MS anthers. Overall, our results reveal that Capana10g000198 is the causal gene underlying the msc-3 locus, providing important theoretical clues and basis for further in-depth study on the regulatory mechanisms of pollen development in pepper.

HMOX1-overexpressing mesenchymal stem cell-derived exosomes facilitate diabetic wound healing by promoting angiogenesis and fibroblast function.

Many scholars have suggested that exosomes (Exos) can carry active molecules to induce angiogenesis and thus accelerate diabetic wound healing. Heme oxygenase-1 (HO-1) encoded by the gene HMOX1 promotes wound healing in DM by enhancing angiogenesis. Nevertheless, whether HMOX1 regulates wound healing in DM through mesenchymal stem cell-derived exosomes (MSC-Exos) remains to be further explored. The primary isolated- and cultured-cells expressed MSC-specific marker proteins, and had low immunogenicity and multi-differentiation potential, which means that MSCs were successfully isolated in this study. Notably, HO-1 protein expression was significantly higher in Exo-HMOX1 than in Exos, indicating that HMOX1 could be delivered to Exos as an MSCs-secreted protein. After verifying the -Exo structure, fibroblasts, keratinocytes, and human umbilical vein endothelial cells (HUVECs) were incubated with Exo-HMOX1 or Exo, and the findings displayed that Exo-HMOX1 introduction promoted the proliferation and migration of fibroblasts, keratinocytes and the angiogenic ability of HUVECs in vitro study. After establishing diabetic wound model mice, PBS, Exo, and Exo-HMOX1 were subcutaneously injected into multiple sites on the 1st, 3rd, 7th, and 14th day, DM injected with Exo-HMOX1 showed faster wound healing, re-epithelialization, collagen deposition, and angiogenesis than those in PBS and Exo groups in vitro study. In summary, Exo-HMOX1 could enhance the activity of fibroblasts, keratinocytes, and HUVEC, and accelerate wound healing by promoting angiogenesis in DM.

Expression of HLA-DR by mesenchymal stromal cells in the platelet lysate era: an obsolete release criterion for MSCs?

BACKGROUND: According to the definition of the International Society for Cell and Gene Therapy (ISCT), mesenchymal stromal cells (MSCs) do not express HLA-DR. This phenotypic marker as a release criterion for clinical use was established at a time when MSCs were expanded in fetal bovine serum (FBS)-containing media. Replacement of FBS with platelet lysate (PLs) as a medium supplement induced a significantly higher fraction of MSCs to express MHC class II antigens. METHODS: As this raised concerns that such MSCs may play the role of antigen-presenting cells for T cells, in the current study, we studied major factors that may induce HLA-DR on MSCs by means of flow cytometry and real-time polymerase chain reaction. The immunomodulatory potential of MSCs was assessed by a mixed lymphocyte reaction. RESULTS: Our results demonstrated that a very low percentage of generated and expanded MSCs in FBS express HLA-DR (median: 1.1%, range: 0.3-22%) compared to MSCs generated and expanded in PLs (median: 28.4%, range: 3.3-73.7%). Analysis of the cytokine composition of ten PLs showed a significant positive correlation between the levels of IL-1ß, IL-4, IL-10, IL-17, bFGF and expression of HLA-DR, in contrast to no correlation with the age of MSC donors and HLA-DR (r = 0.21). Both MSCs expressing low and high levels of HLA-DR expressed class II transactivator (CIITA), a master gene coding for these molecules. Our results demonstrate for the first time that MSCs with constitutively high levels of HLA-DR also express moderate levels of indoleamine 2,3-dioxygenase (IDO). Treatment of MSCs with multiple doses of TGF-ß1 at passage 0 (P0) and passage 1 (P1) completely abrogated HLA-DR and IDO expression. In contrast, treatment of MSCs with a single dose of TGF-ß1 after P0 only partially reduced the expression of HLA-DR and CIITA. Remarkably, increased expression of HLA-DR on MSCs that constitutively express high levels of this antigen after overnight incubation with IFN-γ was rather unaffected by incubation with TGF-ß1. However, treatment of MSCs with TGF-ß1 for 24 h completely abrogated constitutive expression of IDO. CONCLUSIONS: Irrespective of HLA-DR expression at the population level, all MSC preparations significantly inhibited the proliferation of stimulated peripheral blood mononuclear cells, indicating that HLA-DR represents an obsolete release marker for the clinical use of MSCs.

CD34+ synovial fibroblasts exhibit high osteogenic potential in synovial chondromatosis.

Synovial chondromatosis (SC) is a disorder of the synovium characterized by the formation of osteochondral nodules within the synovium. This study aimed to identify the abnormally differentiated progenitor cells and possible pathogenic signaling pathways. Loose bodies and synovium were obtained from patients with SC during knee arthroplasty. Single-cell RNA sequencing was used to identify cell subsets and their gene signatures in SC synovium. Cells derived from osteoarthritis (OA) synovium were used as controls. Multi-differentiation and colony-forming assays were used to identify progenitor cells. The roles of transcription factors and signaling pathways were investigated through computational analysis and experimental verification. We identified an increased proportion of CD34+ sublining fibroblasts in SC synovium. CD34+CD31- cells and CD34-CD31- cells were sorted from SC synovium. Compared with CD34- cells, CD34+ cells had larger alkaline phosphatase (ALP)-stained area and calcified area after osteogenic induction. In addition, CD34+ cells exhibited a stronger tube formation ability than CD34- cells. Our bioinformatic analysis suggested the expression of TWIST1, a negative regulator of osteogenesis, in CD34- sublining fibroblasts and was regulated by the TGF-ß signaling pathway. The experiment showed that CD34+ cells acquired the TWIST1 expression during culture and the combination of TGF-ß1 and harmine, an inhibitor of Twist1, could further stimulate the osteogenesis of CD34+ cells. Overall, CD34+ synovial fibroblasts in SC synovium have multiple differentiation potentials, especially osteogenic differentiation potential, and might be responsible for the pathogenesis of SC.

Challenges of mesenchymal stem cells in the clinical treatment of COVID-19.

The 2019 coronavirus disease (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has brought an enormous public health burden to the global society. The duration of the epidemic, the number of infected people, and the widespread of the epidemic are extremely rare in modern society. In the initial stage of infection, people generally show fever, cough, and dyspnea, which can lead to pneumonia, acute respiratory syndrome, kidney failure, and even death in severe cases. The strong infectivity and pathogenicity of SARS-CoV-2 make it more urgent to find an effective treatment. Mesenchymal stem cells (MSCs) are a kind of pluripotent stem cells with the potential for self-renewal and multi-directional differentiation. They are widely used in clinical experiments because of their low immunogenicity and immunomodulatory function. Mesenchymal stem cell-derived exosomes (MSC-Exo) can play a physiological role similar to that of stem cells. Since the COVID-19 pandemic, a series of clinical trials based on MSC therapy have been carried out. The results show that MSCs are safe and can significantly improve patients' respiratory function and prognosis of COVID-19. Here, the effects of MSCs and MSC-Exo in the treatment of COVID-19 are reviewed, and the clinical challenges that may be faced in the future are clarified.

Current challenges in cell and gene therapy: a joint view from the European Committee of the International Society for Cell & Gene Therapy (ISCT) and the European Society for Blood and Marrow Transplantation (EBMT).

Cell and gene therapy poses evolving challenges. The current article summarizes the discussions held by European Regional Committee of the International Society for Cell & Gene Therapy and the European Society for Blood and Marrow Transplantation (EBMT) on the current challenges in this field, focusing on the European setting. This article emphasizes the imperative assessment of real-world cell and gene therapy activity, advocating for expanded registries beyond hematopoietic transplantation and chimeric antigen receptor-T-cell therapy. Accreditation's role in ensuring standardized procedures, as exemplified by JACIE (The Joint Accreditation Committee of ISCT-Europe and EBMT), is crucial for safety. Access to commercial products and reimbursement variations among countries underscore the need for uniform access to advanced therapy medical products (ATMPs). Academic product development and point-of-care manufacturing face barriers to patient access. Hospital Exemption's potential, demonstrated by some initial experiences, may increase patient accessibility in individual situations. Regulatory challenges, including the ongoing European ATMPs legislation review, necessitate standardized criteria for Hospital Exemption and mandatory reporting within registries. Efforts to combat unproven therapies and fraud involve collaboration between scientific societies, regulatory bodies and patient groups. Finally, is important to highlight the vital role of education and workforce development in meeting the escalating demand for specialized professionals in the ATMP field. Collaboration among scientific societies, academic institutions, industry, regulatory bodies and patient groups is crucial for overcoming all these challenges to increase gene and cell therapy activity in Europe.

Treatment of post-allogeneic hematopoietic stem cell transplant cytopenias with sequential doses of multipotent mesenchymal stromal/stem cells.

BACKGROUND AIMS: Cytopenias after allogeneic stem cell transplantation (allo-SCT) are a common complication, the underlying pathogenic mechanisms of which remain incompletely understood. Multipotent mesenchymal stromal/stem cell (MSC) therapy has been successfully employed in the treatment of immune-related disorders and can aid in the restoration of the hematopoietic niche. METHODS: A phase II clinical trial to assess the efficacy and safety of administering four sequential doses of ex-vivo expanded bone marrow MSCs from a third-party donor to patients with persistent severe cytopenias after allo-SCT was performed. RESULTS: The overall response rate on day 90 was 75% among the 27 evaluable patients (comprising 12 complete responses, 8 partial responses, and 7 with no response). The median time to respond was 14.5 days. Responses were observed across different profiles, including single or multiple affected lineages, primary or secondary timing, and potential immune-mediated or post-infectious pathophysiology versus idiopathic origin. With a median follow-up for surviving patients of 85 months after MSC infusion, 53% of patients are alive. Notably, no adverse events related to MSC therapy were reported. CONCLUSIONS: In summary, the sequential infusion of third-party MSCs emerges as a viable and safe therapeutic option, exhibiting potential benefits for patients experiencing cytopenias following allo-SCT.

Exosomes from SHED-MSC regulate polarization and stress oxidative indexes in THP-1 derived M1 macrophages.

OBJECTIVE: The inhibition of M1 macrophages may be interesting for targeted therapy with mesenchymal stem cell-derived Exosomes (MSC-EXOs). This study aimed to investigate the stem cells of human exfoliated deciduous teeth-derived EXOs (SHED-MSC-EXOs) effect on regulating the pro- and anti-oxidant indexes and inhibiting M1 macrophage polarization. Besides, an in-silico analysis of SHED-MSC-EXO miRNAs as the highest frequency of small RNAs in the exosomes was performed to discover the possible mechanism. METHODS: The flow cytometry analysis of CD80 and CD86 as M1-specific markers confirmed the polarization of macrophages derived from THP-1 cells. After exosome isolation, characterization, and internalization, THP-1-derived M1 macrophages were treated with SHED-MSC-EXOs. M1-specific markers and pro- and anti-oxidant indexes were evaluated. For in-silico analysis of SHED-MSC-EXOs miRNAs, initial miRNA array data of SHED-EXOs is collected from GEO, and the interaction of the miRNAs in M1 macrophage polarization (M1P), mitochondrial oxidative stress (MOS) and LPS-induced oxidative stress (LOS) were analyzed by miRWalk 3.0 server. Outcomes were filtered by 75th percentile signal intensity, score cut-off ≥0.95, minimum free energy (MEF)≤ -20 kcal/mol, and seed = 1. RESULTS: It shows a decrease in the expression of CD80 and CD81, a reduction in pro-oxidant indicators, and an increase in the anti-oxidant indexes (P < 0.05). Computational analysis showed that eight microRNAs of SHED-MSC-EXO miRNAs can bind to and interfere with the expression of candidate genes in the M1P, MOS, and LOS pathways simultaneously. CONCLUSION: SHED-MSCs-EXOs can be utilized to treat conditions related to M1 macrophage-induced diseases (M1IDs) due to their unique physical properties and ability to penetrate target cells easily.

Engineered EVs with pathogen proteins: promising vaccine alternatives to LNP-mRNA vaccines.

Extracellular vesicles (EVs) are tiny, lipid membrane-bound structures that are released by most cells. They play a vital role in facilitating intercellular communication by delivering bioactive cargoes to recipient cells and triggering cellular as well as biological responses. EVs have enormous potential for therapeutic applications as native or engineered exosomes. Native EVs are naturally released by cells without undergoing any modifications to either the exosomes or the cells that secrete them. In contrast, engineered EVs have been deliberately modified post-secretion or through genetic engineering of the secreting cells to alter their composition. Here we propose that engineered EVs displaying pathogen proteins could serve as promising alternatives to lipid nanoparticle (LNP)-mRNA vaccines. By leveraging their unique characteristics, these engineered EVs have the potential to overcome certain limitations associated with LNP-mRNA vaccines.

Mesenchymal stem cell-derived exosomes promote tissue repair injury in rats with liver trauma by regulating gut microbiota and metabolism.

OBJECTIVE: The effects of mesenchymal stem cells (MSCs) and MSC-derived exosomes (MSC-exos) on serum metabolites and intestinal microbiota in rats after liver trauma were discussed. METHODS: Adult Wistar Albino rats were assigned into control, model (liver trauma), MSCs, and MSC-exos groups (n = 6). The study examined changes in the inflammatory environment in liver tissues were analyzed by histological examination and analysis of macrophage phenotypes. Alterations in serum metabolites were determined by untargeted metabonomics, and gut microbiota composition was characterized by 16S rDNA sequencing. Correlations between specific gut microbiota, metabolites, and inflammatory response were calculated using Spearman correlation analysis. RESULTS: Rats with liver trauma after MSCs and MSC-exos treatment exhibited attenuated inflammatory infiltration and necrosis in liver tissues. MSCs and MSC-exos treatment reduced the proportion of M1 macrophages, accompanied by a decrease in inducible nitric oxide synthase (iNOS) and tumor necrosis factor-alpha (TNF-α) levels. Furthermore, MSCs and MSC-exos treatment expanded the proportion of M2 macrophages, accompanied by an increase in arginase-1 (Arg-1) and interleukin-10 (IL-10) levels. The beneficial effects of MSC-exo treatment on rats with liver trauma were superior to those of MSC treatment. The composition and abundance of the gut microbiota and metabolites were altered in pathological rats, whereas MSC and MSC-exo intervention partially restored specific gut microbiota and metabolite alterations. At the phylum level, alterations in Bacteroidota, Proteobacteria, and Verrucomicrobiota were observed after MSC and MSC-exo intervention. At the genus level, Intestinimonas, Alistipes, Aerococcus, Faecalibaculum, and Lachnospiraceae_ND3007_group were the main differential microbiota. 6-Methylnicotinamide, N-Methylnicotinamide, Glutathione, oxidized, ISOBUTYRATE, ASCORBATE, EICOSAPENTAENOATE, GLYCEROL 3-PHOSPHATE, and Ascorbate radical were selected as important differential metabolites. There was a clear correlation between Ascorbate, Intestinimonas/Faecalibaculum and inflammatory cytokines. CONCLUSION: MSC-exos promoted the repair of tissue damage in rats with liver trauma by regulating serum metabolites and intestinal microbiota, providing new insights into how MSC-exos reduced inflammation in rats with liver trauma.

Human umbilical cord-derived mesenchymal stem cells attenuate hepatic stellate cells activation and liver fibrosis.

BACKGROUND: Liver cirrhosis, a prevalent chronic liver disease, is characterized by liver fibrosis as its central pathological process. Recent advancements highlight the clinical efficacy of umbilical cord mesenchymal stem cell (UC-MSC) therapy in the treatment of liver cirrhosis. METHODS AND RESULTS: We investigated the pharmacodynamic effects of UC-MSCs and MSC conditional medium (MSC-CM) in vivo, utilizing a carbon tetrachloride (CCl4)-induced fibrotic rat model. Concurrently, we assessed the in vitro impact of MSCs and MSC-CM on various cellular process of hepatic stellate cells (HSCs), including proliferation, apoptosis, activation, immunomodulatory capabilities, and inflammatory factor secretion. Our results indicate that both MSCs and MSC-CM significantly ameliorate the pathological extent of fibrosis in animal tissues, reducing the collagen content, serum biochemical indices and fibrosis biomarkers. In vitro, MSC-CM significantly inhibited the activation of the HSC line LX-2. Notably, MSC-CM modulated the expression of type I procollagen and TGFß-1 while increasing MMP1 expression. This modulation restored the MMP1/TIMP1 ratio imbalance and extracellular matrix deposition in TGFß-1 induced fibrosis. Both MSCs and MSC-CM not only induced apoptosis in HSCs but also suppressed proliferation and inflammatory cytokine release from activated HSCs. Furthermore, MSCs and MSC-CM exerted a suppressive effect on total lymphocyte activation. CONCLUSIONS: UC-MSCs and MSC-CM primarily modulate liver fibrosis severity by regulating HSC activation. This study provides both in vivo and in vitro pharmacodynamic evidence supporting the use of MSCs in liver fibrosis treatment.

In vitro anti-leukemic effect of Wharton's jelly derived mesenchymal stem cells.

BACKGROUND: Mesenchymal stem cells (MSCs) have the ability to self-renew and are multi-potent. They are a primary candidate for cell-based therapy due to their potential anti-cancer effects. The aim of this study was to evaluate the in vitro anti-leukemic effect of Wharton's Jelly-derived MSC (WJ-MSC) on the leukemic cell lines K562 and HL-60. METHODS: In this present study, WJ-MSCs were isolated from human umbilical cord. The cells were incubated according to the standard culture conditions and characterized by flow cytometry. For experiments, WJ-MSC and leukemic cells were incubated in the direct co-culture at a ratio of 1:5 (leukemia cells: WJ-MSC). HUVEC cells were used as a non-cancerous cell line model. The apoptotic effect of WJ-MSCs on the cell lines was analyzed using Annexin V/PI apoptosis assay. RESULTS: After the direct co-culture of WJ-MSCs on leukemic cell lines, we observed anti-leukemic effects by inducing apoptosis. We had two groups of determination apoptosis with and without WJ-MSCs for all cell lines. Increased apoptosis rates were observed in K562 and HL-60 cell lines, whereas the apoptosis rates in HUVEC cells were low. CONCLUSIONS: MSCs are known to inhibit the growth of tumors of both hematopoietic and non-hematopoietic origin in vitro. In our study, WJ-MSC treatment strongly inhibited the viability of HL-60 and K562 and induced apoptosis. Our results also provided new insights into the inhibition of tumor growth by WJ-MSCs in vitro. In the future, WJ-MSCs could be used to inhibit cancer cells in clinical applications.

Modulation of NLRP3 inflammasomes activation contributes to improved survival and function of mesenchymal stromal cell spheroids.

Mesenchymal stem cells (MSCs) are ubiquitous multipotent cells that exhibit significant therapeutic potentials in a variety of disorders. Nevertheless, their clinical efficacy is limited owing to poor survival, low rate of engraftment, and impaired potency upon transplantation. Spheroidal three-dimensional (3D) culture of MSCs (MSC3D) has been proven to better preserve their in vivo functional properties. However, the molecular mechanisms underlying the improvement in MSC function by spheroid formation are not clearly understood. NLRP3 inflammasomes, a key component of the innate immune system, have recently been shown to play a role in cell fate decision of MSCs. The present study examined the role of NLRP3 inflammasomes in the survival and potency of MSC spheroids. We found that MSC3D led to decreased activation of NLRP3 inflammasomes through alleviation of ER stress in an autophagy-dependent manner. Importantly, downregulation of NLRP3 inflammasomes signaling critically contributes to the enhanced survival rate in MSC3D through modulation of pyroptosis and apoptosis. The critical role of NLRP3 inflammasome suppression in the enhanced therapeutic efficacy of MSC spheroids was further confirmed in an in vivo mouse model of DSS-induced colitis. These findings suggest that 3D culture confers survival and functional advantages to MSCs by suppressing NLRP3 inflammasome activation.

The exo-microRNA (miRNA) signaling pathways in pathogenesis and treatment of stroke diseases: Emphasize on mesenchymal stem cells (MSCs).

A major factor in long-term impairment is stroke. Patients with persistent stroke and severe functional disabilities have few therapy choices. Long noncoding RNAs (lncRNAs) may contribute to the regulation of the pathophysiologic processes of ischemic stroke as shown by altered expression of lncRNAs and microRNA (miRNAs) in blood samples of acute ischemic stroke patients. On the other hand, multipotent mesenchymal stem cells (MSCs) increase neurogenesis, and angiogenesis, dampen neuroinflammation, and boost brain plasticity to improve functional recovery in experimental stroke models. MSCs can be procured from various sources such as the bone marrow, adipose tissue, and peripheral blood. Under the proper circumstances, MSCs can differentiate into a variety of mature cells, including neurons, astrocytes, and oligodendrocytes. Accordingly, the capability of MSCs to exert neuroprotection and also neurogenesis has recently attracted more attention. Nowadays, lncRNAs and miRNAs derived from MSCs have opened new avenues to alleviate stroke symptoms. Accordingly, in this review article, we examined various studies concerning the lncRNAs and miRNAs' role in stroke pathogenesis and delivered an overview of the therapeutic role of MSC-derived miRNAs and lncRNAs in stroke conditions.

Training Outcomes and Satisfaction in Canadian MD/PhD and MD/MSc Programs: Findings from a National Survey.

PURPOSE: Despite the impact of physician-scientists on scientific discovery and translational medicine, several reports have signalled their declining workforce, reduced funding, and insufficient protected research time. Given the paucity of outcome data on Canadian MD/PhD programs, this study presents a national portrait of the sociodemographic characteristics, training trajectories, productivity, and satisfaction in trainees and alumni from Canadian MD/PhD and MD/MSc programs. METHODS: Quantitative data were collected in a national survey launched in 2021. Respondents included 74 MD/PhD alumni and 121 trainees across 12 Canadian MD/PhD and MD/MSc programs. RESULTS: Among MD/PhD alumni, 51% were independent practitioners/researchers while others underwent residency training. Most trainees (88%) were in MD/PhD programs. Significantly more alumni identified as men than did trainees. Significantly more alumni conducted clinical and health services research, while more trainees conducted basic science research. Average time to MD/PhD completion was 8 years, with no correlation to subsequent research outcomes. Self-reported research productivity was highest during MD/PhD training. Concerning training trajectories, most alumni completed residency, pursued additional training, and practised in Canada. Finally, regression models showed that trainees and alumni were satisfied with programs, with significant moderators in trainee models. CONCLUSION: Survey findings showed Canadian MD/PhD and MD/MSc programs recruit more diverse cohorts of trainees than before, provide productive research years, and graduate alumni who pursue training and academic employment in Canada. Both alumni and trainees are largely satisfied with these training programs. The need to collect in-depth longitudinal data on Canadian MD/PhD graduates to monitor diversity and success metrics is discussed.