Stem Cell Research & Therapy最新文献

Background: Spinal cord injury (SCI) leads to persistent neurological deficits partly by disruption of the blood-spinal cord barrier (BSCB). Small extracellular vesicles (sEVs) from human umbilical cord mesenchymal stem cells (hUC-MSCs) can promote BSCB repair, but their active components remain unclear. This study examined whether miR-149 carried by hUC-MSC-derived sEVs (hUC-MSCs-sEVs) protects the BSCB after SCI by targeting endothelin-1 (ET-1).

Methods: Human brain microvascular endothelial cells (HBMECs) were subjected to oxygen-glucose deprivation/reoxygenation (OGD/R) to model barrier injury, and rats underwent a thoracic SCI. hUC-MSCs-sEVs were isolated and loaded with miR-149 mimics or inhibitors. Endothelial cell viability, paracellular permeability (FITC-dextran assay), and junction protein levels (ZO-1, Claudin-5, β-Catenin, Occludin) were measured by viability assays, Western blot, and immunofluorescence. ET-1 levels and PI3K/Akt pathway activation were measured by ELISA and Western blot. In SCI rats, sEVs (with or without the miR-149 inhibitor) were injected; motor function (BBB locomotor score), BSCB permeability (Evans blue/FITC-dextran leakage) and spinal cord histology were evaluated.

Results: hUC-MSCs-sEVs were internalized by HBMECs and significantly improved cell survival and barrier function after OGD/R. sEVs treatment restored tight and adherens junction proteins and suppressed OGD/R-induced ET-1 upregulation and PI3K/Akt activation. OGD/R reduced miR-149 expression, which was rescued by sEVs. sEVs loaded with miR-149 mimic further enhanced these protective effects, whereas a miR-149 inhibitor abolished them. Notably, co-administration of an ET-1 receptor antagonist reversed the barrier disruption caused by miR-149 inhibition. In vivo, hUC-MSCs-sEVs treatment improved locomotor recovery and reduced BSCB leakage and tissue damage, whereas miR-149 inhibition abolished these benefits.

Conclusions: hUC-MSC-derived exosomal miR-149 preserves BSCB integrity and promotes functional recovery after SCI by targeting ET-1 and inhibiting the PI3K/Akt pathway, thereby enhancing junctional protein expression. The miR-149/ET-1 axis may represent a promising therapeutic target for SCI.

Background: Research indicates that the occurrence of periodontitis is related to oxidative stress and mitochondrial dysfunction. Alleviating oxidative stress and mitochondrial dysfunction may be a promising treatment strategy for periodontitis. In this study, bone marrow mesenchymal stem cells (BMSCs) were pretreated with lipopolysaccharide (LPS), and their derived exosomes (LPS-BMSCs-Exo) were extracted. In vitro and in vivo experiments were conducted to study the therapeutic effects of alleviating oxidative stress, mitochondrial disorders, and periodontitis.

Methods: BMSCs were pretreated with LPS, and LPS-BMSCs-Exo were extracted and identified via transmission electron microscopy (TEM), nanoparticle tracking analysis (NTA), and Western blotting. The biosafety of the exosomes was assessed through CCK-8, migration, and uptake assays. A cell oxidative stress model was established and treated with BMSCs-Exo or LPS-BMSCs-Exo, the following tests were performed: the effects of the two types of exosomes on the oxidative stress of periodontal ligament stem cells (PDLSCs) were determined, the mitochondrial state and the membrane potential were detected, the content of adenosine triphosphate (ATP) was determined, apoptosis was detected, and the effect of the exosomes on the osteogenic ability of the PDLSCs was detected. A periodontitis rat model was established, and PBS, BMSCs-Exo, and LPS-BMSCs-Exo were administered separately. Micro-CT, HE staining, Masson staining, immunohistochemistry, and ROS fluorescence staining were used to evaluate the therapeutic effect of each group on periodontitis in rats.

Results: The proposed LPS-BMSCs-Exo exhibits characteristics similar to those of exosomes, can be successfully taken up and internalized by PDLSCs, and promotes the proliferation and migration of these cells. LPS-BMSCs-Exo can effectively improve the oxidative stress state, alleviate mitochondrial dysfunction in cells, increase membrane potential, enhance ATP content, reduce apoptosis, and improve the osteogenic ability of PDLSCs. Micro-CT data revealed that alveolar bone-related indicators were significantly increased after LPS-BMSCs-Exo treatment, which could reduce the degradation and inflammation of periodontal tissue in rats and alleviate their oxidative stress.

Conclusion: LPS-BMSCs-Exo can significantly alleviate the oxidative stress and mitochondrial dysfunction caused by periodontitis in periodontal tissue, thereby reducing inflammation in periodontal tissue and alveolar bone resorption.

Background: Premature ovarian insufficiency (POI) is a clinically challenging condition characterized by amenorrhea and infertility in women less than 40 years of age. Although both human amniotic epithelial cells (hAECs) and human umbilical cord mesenchymal stem cells (hUC-MSCs) have shown promise in treating POI, their comparative therapeutic efficacy and mechanisms remain poorly understood.

Methods: hAECs and hUC-MSCs were isolated from human amniotic membrane and umbilical cords, respectively, and characterized using standard protocols. A chemotherapy-induced POI mouse model was established to evaluate follicular development, ovarian fibrosis, and fertility recovery after hAEC and hUC-MSC transplantation. Longitudinal in vivo bioluminescence imaging was used to track and compare the biodistribution and retention rates of the transplanted cells. RNA sequencing and in vitro functional assays under oxidative stress and apoptosis-induced conditions were employed to analyze the differential stress responses of hAECs and hUC-MSCs. Furthermore, cytokine arrays were utilized to profile their secretomes.

Results: In the chemotherapy-induced POI mouse model, both hAECs and hUC-MSCs transplantation improved ovarian function, as evidenced by increased ovarian weight, restored estrous cycle, elevated follicle counts, reduced fibrosis, and enhanced fertility. In vivo imaging revealed that both cell types primarily homed to the lungs, liver, and spleen post-transplantation, with signal intensity declining over time. Quantitative analysis revealed significantly longer in vivo retention of hAECs compare to hUC-MSCs. RNA sequencing and in vitro assays confirmed the superior antioxidant capacity of hAECs under stress conditions. Cytokine profiling showed that hAEC-CM was enriched in pro-angiogenic factors, while hUC-MSC-CM contained higher levels of immunoregulatory cytokines, a functional difference further validated by in vitro experiments.

Conclusion: Our findings demonstrate that both hAECs and hUC-MSCs are effective in restoring ovarian function and fertility in a chemotherapy-induced POI mouse model. However, these two cell types exhibit distinct therapeutic advantages attributable to their differential metabolic kinetics and paracrine profiles. Specifically, hAECs displayed prolonged in vivo retention rates compared to hUC-MSCs, consistent with their enhanced antioxidant capabilities. In terms of secretory function, hAECs demonstrated superior pro-angiogenic activity, while hUC-MSCs exhibited stronger immunomodulatory effects. These distinct properties provide critical insights for cell-type-specific selection in developing targeted therapies for ovarian dysfunction.

Introduction: Stem cell therapy has emerged as a potential regenerative approach for Acute myocardial infarction (AMI). Despite decades of research and advancement in acute myocardial infarction (AMI) management, translating innovative therapies from bench to bedside remains a central challenge. Nonetheless, clinical outcomes exhibit considerable variability. This review provides a comprehensive overview of the clinical landscape of stem cell therapy for AMI, specifically focusing on how variations in cell type, delivery timing, routes, and dosages can affect cell therapy efficacy.

Methods: This study is a systematic review of randomized clinical trials. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were followed, and the study was conducted in accordance with the Cochrane Handbook for Systematic Reviews of Interventions.

Results: After searching the relevant databases, a total of 5276 studies were assessed, and 43 trials were considered eligible for inclusion in the present systematic review. The safety and efficacy of various types of stem cells, including bone marrow-derived mononuclear cells (BM-MNCs), mesenchymal stem cells (MSCs), cardiac progenitor cells, and, more recently, induced pluripotent stem cells, have been evaluated in numerous clinical trials and meta-analyses. Among these, BM-MNCs and MSCs have been the most extensively studied. Although results vary from trial to trial and can even be contradictory, from frank failures to monumental achievements, overall, the evidence supports modest but statistically significant improvements in surrogate endpoints, such as left ventricular ejection fraction (LVEF), ventricular remodeling, and reduced infarct size.

Conclusion: We have critically reviewed how methodological approaches-especially the definitions of endpoints and clinical outcome measures-have significantly influenced the reported efficacy and direction of the field. The interpretation of clinical trial results in cell therapy for AMI is heavily impacted by the specific metrics used to define success. A key focus is distinguishing between clinical trials on patients with acute and recent myocardial infarction (which is the main focus of this review) and those with chronic ischemic or non-ischemic cardiomyopathies, as they involve different treatment strategies. Patient selection is essential for improving responses in patients with AMI. Those with a severely reduced LVEF (LVEF < 40%) and younger age tend to benefit more. Limiting the transplantation window to the first 3-7 days after AMI may improve the intervention's effectiveness.

Background: Small extracellular vesicles originating from adipose-derived mesenchymal stromal cells (ADSC-sEVs) have excellent therapeutic value in acute tendon injury. However, their mechanism and effects have not been fully elucidated. This study aimed to identify the key subsets and mechanisms of action of ADSC-sEVs involved in the repair of complete tendon tear caused by acute injury.

Methods: Based on our previous research demonstrating that ADSC-sEVs improve the quality of acute tendon injury repair, the present study utilized second-generation sequencing and bioinformatics to predict the key role of the TNFAIP6^- ADSC subgroup in acute tendon injury repair. We constructed different ADSC-sEVs through ADSC transfection and treated tendon stem cells for further exploration. EdU, cell scratch, and Transwell assays were used to evaluate cell proliferation and migration in vitro. Western blot and quantitative real-time polymerase chain reaction analyses were performed. Histopathological, immunohistochemical, and biomechanical testing were used for in vivo validation.

Results: TNFAIP6^- ADSC-sEVs significantly improved the therapeutic effect of ADSC-sEVs on acute tendon injury, which was related to the high expression of let-7c-5p. Application of different ADSC-sEVs in vitro and in vivo identified CRCT1/JAK2/STAT3 as a key downstream signaling pathway regulated by let-7c-5p.

Conclusions: Our findings enhance the current understanding of how TNFAIP6^- ADSC-sEVs exert healing properties in acute tendon injury through the let-7c-5p/CRCT1/JAK2/STAT3 signaling pathway. Furthermore, this study proposes a concept for constructing conditional ADSC-sEVs to enhance their inherent therapeutic effects.

Human mesenchymal stromal cells (hMSCs) are currently at the center of interest in many randomized and non-randomized clinical trials. According to the data, the number of trials on hMSCs has increased rapidly over time. However, the safety of this treatment, despite some available evidence, remains questionable. Routinely collected data (RCD) has become a helpful approach for gathering clinical data, especially in clinical trials. This method of data collection has helped investigators overcome the limitations of randomized controlled trials (RCTs), such as ensuring long-term follow-ups. Herein, the potential role of RCD in investigating the safety of hMSCs in RCTs, particularly concerns about their possible pro-tumorigenic potential, is discussed. The patterns of recent trials in this field suggest high feasibility and the potential for using RCD for this purpose.

Backgroud: This study systematically evaluated the immunomodulatory function of PD-L1-positive mesenchymal stem cells (PD-L1(+) MSCs) using single-cell RNA sequencing (scRNA-seq) and investigated their roles in suppressing inflammation and regulating pathological bone formation in curdlan-induced SKG ankylosing spondylitis (AS) mouse models.

Methods: scRNA-seq identified MSC subpopulations with high immunomodulatory capacity and key biomarker PD-L1 for subpopulation classification. In vitro co-culture experiments were conducted to evaluate the effects of MSC subpopulations on T-cell proliferation and TNF-α levels. In vivo experiments were performed in forty-eight SKG mouse models to analyze the effects of MSC subpopulations on joint inflammation scores, T-cell subset proportions, inflammatory cytokines, histopathology, and pathological bone formation.

Results: scRNA-seq revealed significant heterogeneity in MSCs under inflammatory stimulation, with the immunomodulatory subpopulation exhibiting high expression of PD-L1 and IDO. In vitro experiments demonstrated that PD-L1(+) MSCs significantly suppressed T-cell proliferation and reduced TNF-α levels. Joint redness and swelling scores showed that the PD-L1(+) MSC group exhibited the most significant improvement in arthritis, while the IL-17Ai, PD-L1(-) MSC, and MSC groups also effectively reduced inflammation, with significantly lower scores than the model control(MC) group. Histological analysis revealed severe inflammatory cell infiltration in the MC group, while the IL-17Ai, PD-L1(+) MSC, and MSC groups exhibited reduced infiltration. Immunohistochemical analysis further confirmed these findings, with PD-L1(+) MSCs exhibiting a significant reduction in TNF-α and IL-17A-positive cells (P < 0.0001 and P < 0.01, respectively).PD-L1(+) MSCs regulated immune responses by reducing Th17 cell proportions, increasing Th2 and Treg cell proportions, and significantly lowering pro-inflammatory cytokines IFN-γ, IL-17A, and TNF-α. MicroCT analysis indicated that the PD-L1(+) MSC, MSC, and IL-17Ai group effectively suppressed pathological bone formation through immunomodulation, whereas the PD-L1(-) MSC group showed weaker effects, underscoring the importance of PD-L1 in regulating bone formation.

Conclusion: hUC-MSCs demonstrated significant therapeutic effects in the AS mouse model, particularly the PD-L1(+) MSCs, which inhibited joint inflammation and pathological new bone formation through immunomodulatory mechanisms. These findings provide valuable insights into the therapeutic mechanisms of AS treatment.

Introduction: Direct reprogramming of fibroblasts into cardiomyocytes by overexpressing cardiac transcription factors Gata4, Mef2c, and Tbx5 (GMT) is a promising way for cardiac repair, however, the low reprogramming efficiency remains a significant challenge. Cellular senescence, an irreversible cell-cycle arrest occurring in mitotic cells, has been reported to influence the efficiency of induced pluripotent stem cell (iPSC) reprogramming.

Methods: We established an inducible GMT expression system in mouse embryonic fibroblasts (MEFs) and human fetal cardiac fibroblasts (hFCFs) using the PiggyBac transposon system. RNA sequencing was performed to identify genes associated with cellular senescence during reprogramming. Selected senescence-related genes were knocked down using shRNA, and their impact on reprogramming efficiency was assessed via flow cytometry, gene expression analysis, and staining for senescence and apoptosis markers.

Results: Direct cardiac reprogramming induced cellular senescence and apoptosis, evidenced by enhanced β-Gal staining, elevated expression of senescence markers P16 and GLB1, and increased apoptosis rates. RNA sequencing and gene set enrichment analysis (GSEA) revealed significant upregulation of senescence-related genes (RB1, RBBP4, RBBP7, CBX8, and CDKN1B). Knockdown of these genes, particularly RB1, significantly enhanced reprogramming efficiency, increasing the proportion of GFP + cells in MEFs and α-actinin + cells in hFCFs. RB1 inhibition also reduced senescence marker levels and upregulated endogenous cardiac transcription factors GATA4 and MEF2C.

Conclusions: Our findings demonstrate that cellular senescence might serves as a barrier to direct cardiac reprogramming and offer novel insights into the regulatory mechanisms involved in this process.

Background: Mesenchymal stem cells (MSCs) are highly sensitive to fluctuations in culture process parameters (CPPs), which remain a major barrier to consistent product quality in cell manufacturing. A mechanistic understanding of how cells respond to and encode these variations is essential to enable standardization under a quality-by-design paradigm.

Methods: To address this, we propose the concept of cell manufacturability, defined as the intrinsic ability of cells to maintain their functional phenotype in response to variable inputs. Drawing inspiration from the Japanese concept of yuragi (gentle, adaptive fluctuation), we profiled histone modifications (H3K4me3 and H3K27me3) at the promoters of critical quality attribute (CQA) genes using chromatin immunoprecipitation followed by quantitative PCR (ChIP-qPCR). We established a cell potency index based on the H3K4me3/H3K27me3 ratio. Weighted principal component analysis (PCA) was applied to derive two composite indices: the Cell Susceptibility Index (CSI), indicating environmental responsiveness, and the Cell Comparability Index (CCI), representing inter-donor and process consistency.

Results: The CSI and CCI captured distinct, condition-dependent patterns. Under low-stress conditions (e.g., early passages and low seeding density), a positive correlation between CSI and CCI reflected reproducible adaptive plasticity. Conversely, high-stress cultures exhibited a strong negative correlation, which was indicative of unstable epigenetic responses. These patterns were consistently observed across different MSC sources, underscoring the generalizability of the framework.

Conclusions: This study highlights CSI and CCI as quantitative, chromatin-based metrics that offer a mechanistic basis for characterizing MSC plasticity and manufacturing robustness. Integration of these indices into the evaluation of cell manufacturability offers a predictive and scalable approach to enhance standardization and batch comparability in MSC production processes.

Background: Heterotopic ossification (HO) pathogenesis involves ROS-driven stem cell differentiation. Carnosic acid (CA), a natural antioxidant, remains unexplored for HO.

Methods: In vitro, tendon-derived stem cells (TDSCs) were stimulated with IL-1β, and CA was used for intervention to assess its effects on differentiation and ROS production via real-time quantitative PCR (qPCR), western blotting (WB), and immunofluorescence. Additionally, a burn and Achilles tendon transection-induced mouse model of traumatic HO was established to evaluate the therapeutic potential of CA.

Results: In vitro, CA activated nuclear factor erythroid 2-related factor 2 (Nrf2) and inhibited nicotinamide adenine dinucleotide phosphate oxidase 1 (NOX1), leading to increased antioxidant enzyme activity and reduced intracellular ROS levels. CA also regulated the PTEN/AKT signaling pathway, suppressing osteogenic and chondrogenic differentiation of TDSCs. In vivo, micro-computed tomography (Micro-CT) and histological analyses demonstrated that CA activated Nrf2 and enhanced antioxidant enzyme expression, thereby inhibiting osteogenic and chondrogenic factor expression in Achilles tendon tissue and reducing HO formation.

Conclusions: CA is a novel HO therapeutic by dual targeting of oxidative stress and differentiation pathways.