Freshly thawed umbilical cord-derived mesenchymal stem cells (FT-UC MSCs) often show reduced post-thaw functionality, limiting their use as off-the-shelf cell therapies. This study investigated whether an ion-enriched solution (IES) could improve FT-UC MSC adhesion and cartilage repair-associated outcomes. UC MSCs were categorized as cryopreserved and culture-recovered UC MSCs (CP-UC MSCs) or FT-UC MSCs. Adhesion was assessed in vitro on type I collagen and ex vivo on human osteoarthritic cartilage using saline, IES, or magnesium chloride as carriers. In vivo, rats with full-thickness cartilage defects received intra-articular injections of IES alone, CP-UC MSCs in saline, or FT-UC MSCs in IES. Cartilage repair was evaluated by ICRS macroscopic and histological scoring, immunohistochemistry, and static weight-bearing. FT-UC MSCs showed reduced proliferation, metabolic activity, and adhesion compared with CP-UC MSCs. IES significantly enhanced FT-UC MSC adhesion in vitro and ex vivo, with magnesium chloride (MgCl2) as the major contributor and sodium acetate (NaOAc) as a possible additional contributor. In vivo, FT-UC MSCs delivered with IES showed macroscopic and histological repair outcomes comparable to CP-UC MSCs delivered with saline, including lower subchondral abnormality and inflammation scores, lower type I collagen staining, and a favorable matrix profile at 8 weeks. FT-UC MSCs delivered with IES showed improved post-thaw adhesive function and repair-associated outcomes comparable to CP-UC MSCs delivered with saline in a rat full-thickness cartilage defect model. These findings support the potential utility of IES as a practical delivery carrier for freshly thawed UC-MSCs without an extended culture-recovery step, while further studies including an FT-UC MSCs + saline group are required to isolate the specific in vivo contribution of IES.
Hyperuricemic nephropathy (HN) arises from excessive accumulation of uric acid, leading to subsequent renal injury. Mesenchymal stem cells-derived small extracellular vesicles (MSC-sEVs) have demonstrated beneficial effects in promoting tissue repair across various injury models. However, their potential therapeutic role in HN remains unknown. We isolated and characterized MSC-sEVs by transmission electron microscopy, nanoparticle tracking analysis, and Western blotting. A rat model of HN was established by daily administration of adenine and potassium oxonate for three weeks, after which MSC-sEVs were intravenously injected. Renal function, histopathological changes, and fibrotic markers were assessed, while the involvement of epithelial-mesenchymal transition (EMT) was examined both in vivo and in UA-treated HK-2 cells. Regenerative and anti-fibrotic outcomes were examined through Masson’s trichrome staining and immunohistochemistry (α-SMA). Rats with HN exhibited significant renal dysfunction and marked interstitial fibrosis. MSC-sEVs treatment significantly improved renal function, as evidenced by reduced serum creatinine and blood urea nitrogen, and attenuated tubulointerstitial fibrosis, collagen deposition, and α-SMA expression in HN rats. Mechanistically, UA induced a classic EMT phenotype in renal tubular cells in vivo and in vitro, characterized by downregulation of E-cadherin and upregulation of N-cadherin and vimentin, all of which were markedly reversed by MSC-sEVs. Notably, miRNA sequencing revealed that MSC-sEVs are enriched in multiple miRNAs that have been previously reported to target EMT-associated signaling pathways, suggesting a potential miRNA-mediated mechanism. Our study found that MSC-sEVs can effectively reverse renal EMT in HN, thereby promoting the restoration of renal function, revealing a possible mechanism by which MSC-sEVs treatment in renal fibrosis associated with HN. Taken together, this study provides a foundation for innovative therapeutic approaches and advanced pharmacological strategies for HN.
Brown adipose tissue (BAT) dissipates energy via non-shivering thermogenesis, making it a promising therapeutic target for metabolic diseases. However, effective strategies for directing human stem cells toward brown adipocyte lineage remain to be fully established. Here, as an early commitment modulation study, we investigated whether stage-specific exposure to bone morphogenetic protein 7 (BMP7) during initial induction enhances brown adipocyte-like features and β-adrenergic responsiveness in tonsil-derived mesenchymal stem cells (TMSCs). TMSCs were induced to differentiate into white adipocyte-like cells (WA) or brown adipocyte-like cells using a two-step protocol. Among the brown adipogenic groups, BMP7 (50 ng/mL) was additionally administered during the early commitment stage (step 1) in one group (BA + BMP7) but not the other (BA), while both groups received BMP7 throughout the subsequent step 2 induction, allowing the stage-specific effect of early BMP7 priming to be evaluated. Lineage commitment and brown adipocyte-like features were assessed via Oil Red O staining, qPCR, western blotting, MitoTracker staining, and cAMP responsiveness upon β-adrenergic stimulation (isoproterenol). Early BMP7 priming during the initial commitment stage effectively promoted brown adipocyte lineage commitment. Compared with the WA and BA group, BA+BMP7 cells exhibited significantly increased UCP1 protein expression, along with non-significant upward trends in ZIC1 and PGC1α, and a significant increase in the progenitor commitment marker Myf5. Furthermore, brown adipogenic differentiation significantly increased mitochondrial mass, showing an additional upward trend in the early BMP7-primed group, whereas β-adrenergic functional responsiveness distinguished the two brown adipogenic groups: upon isoproterenol stimulation, BA + BMP7 cells exhibited an increase in intracellular cAMP accumulation relative to their own basal state, alongside enhanced HSL phosphorylation, a pattern not observed to the same extent in brown-differentiated cells without early BMP7 priming. This early commitment modulation study demonstrates that temporal BMP7 exposure enhances brown adipocyte-like features and adrenergic sensitivity in TMSCs. Early stage-specific signaling modulation provides a viable strategy for directing stem cell lineage commitment toward brown adipocyte-like phenotypes for metabolic research.
Specific binding of the hepatitis B virus (HBV) pre-S1 protein to Na+/taurocholate Cotransporting Polypeptide (NTCP) on the surface of hepatocytes mediates viral entry into host cells. Exosomes, which serve as natural delivery vehicles, can protect their cargo from degradation in the extracellular environment. Umbilical cord mesenchymal stem cell (UC-MSC)-derived exosomes were isolated and characterized. The gene sequence encoding the CD90 C-terminal signal peptide was fused with the pre-S1 gene and cloned into a lentiviral vector (VP045-U6-PGK-preS1-CD90-hygro), enabling membrane anchoring of pre-S1 on UC-MSC-derived exosomes. PKH26 probe, Phalloidin-AF488 probe, and DiR dye were used to explore the targeting of reconstituted UC-MSC-derived exosomes on hepatocytes and liver. Isolated UC-MSCs exhibited fibroblast-like morphology and retained the capacity to differentiate into osteoblasts, adipocytes, and chondrocyte. The immunophenotype of UC-MSCs was characterized as CD34−CD45−CD44+CD73+CD90+CD105+Oct-4+. UC-MSC-derived exosomes exhibited a cup-shaped bilayer structure, with a diameter of 78.47 ± 13.46 nm and a concentration of 1.28 × 1010 particles/mL. The VP045-U6-PGK-preS1-CD90-hygro lentivirus successfully mediated pre-S1 expression on the membranes of UC-MSC-derived exosomes. In vitro, hepatocytes (HepG2.2.15 and HepaRG cells) internalized significantly greater amounts of reconstituted UC-MSC-derived exosomes than native exosomes, with the effect being particularly pronounced in HepG2.2.15 cells. No significant difference was observed in lung cells. In vivo, reconstituted UC-MSC-derived exosomes were predominantly accumulated in the liver of BALB/c mice, whereas minimal signals were detected in the lung, spleen and kidney. UC-MSC-derived exosomes expressing pre-S1 exhibit specific tropism for hepatocytes and liver tissue. These engineered exosomes represent a promising delivery platform for therapeutic drugs and nucleic acid cargos in HBV-targeted therapy.
Mesenchymal stem cells (MSCs) are multipotent stromal cells with dual regenerative and immunomodulatory properties that have attracted growing attention in cancer therapy. Their inherent tumor-homing ability enables localized delivery of therapeutic agents, while their capacity to regulate both innate and adaptive immunity positions MSCs at the interface of stromal biology and cancer immunotherapy. However, MSC functions are highly context-dependent and vary across tumor types. This review summarizes preclinical and clinical evidence on the immunomodulatory roles of MSCs in cancer. Experimental studies and early-phase clinical trials involving unmodified, preconditioned, and genetically engineered MSCs, as well as MSC-derived extracellular vesicles, were evaluated. Unmodified MSCs often promote immune evasion by expanding regulatory T cells, expressing checkpoint ligands, and secreting immunosuppressive and metabolic mediators, such as IDO, nitric oxide, and PGE2. In contrast, engineered or primed MSCs can redirect immune responses toward activation, enhancing NK- and T-cell cytotoxicity and enabling targeted delivery of cytokines, oncolytic viruses, and pro-apoptotic ligands. Early clinical trials generally demonstrate safety and feasibility; however, efficacy remains variable due to heterogeneity of MSC sources, manufacturing challenges, and lack of standardized potency assays. Notably, tumor-promoting effects have been reported under specific conditions. MSCs Represent a highly plastic and programmable platform for immune modulation in cancer. Advances in genetic engineering and extracellular vesicle-based strategies may improve therapeutic efficacy while reducing oncogenic risk.
