Cell Regeneration最新文献

The Wnt signaling pathway critically regulates the osteogenic differentiation in periodontal ligament stem cells (PDLSCs). However, the functional contributions of this pathway under inflammatory conditions remain unclear. This study investigated the effect and underlying mechanisms of the FRZB-Wnt5a-mitochondrial axis on the osteogenic differentiation capacity of PDLSCs under inflammatory conditions. PDLSCs were isolated from healthy teeth and exposed to lipopolysaccharide (LPS) to mimic an inflammatory microenvironment. The Wnt pathway-related molecules were assessed, and the osteogenic differentiation capacity and mitochondrial function of PDLSCs were evaluated. To elucidate its regulatory role, we employed gene transfection to establish an FRZB (Frizzled-Related Protein) overexpression model. Results showed that inflammation significantly impaired osteogenic differentiation and activated Wnt/β-catenin signaling. Mitochondrial dysfunction was also observed, including reduced membrane potential, increased calcium and reactive oxygen species (ROS) levels, suppressed autophagic flux, and altered mitochondrial morphology. Notably, FRZB overexpression partially restored mitochondrial function and the osteogenic differentiation capacity of PDLSCs. These results demonstrated that FRZB serves as a pivotal regulator of osteogenic differentiation in PDLSCs. We found that inflammation downregulates FRZB expression, thereby activating Wnt/β-catenin signaling, which leads to mitochondrial dysfunction and ultimately impairs osteogenesis. These findings reveal a mechanism by which inflammation suppresses osteogenesis in PDLSCs and highlight FRZB as a promising therapeutic target for periodontitis.

Skeletal muscle aging is characterized by a functional decline in muscle stem cells (MuSCs), yet the key regulatory mechanisms driving this deterioration remain poorly understood. By integrating transcriptomic profiles from aged MuSCs with data from C2C12 cells exposed to spaceflight conditions (which mimic an aging-like phenotype), we identified MORF4-related gene on chromosome 15 (MRG15) as a putative epigenetic regulator involved in age-related myogenic decline. Using a MuSC-specific inducible knockout (iKO) mouse model, we found that loss of MRG15 severely compromises myogenic differentiation and muscle regeneration. Subsequent RNA sequencing of iKO MuSCs, combined with ChIP-seq analysis of histone modifications, revealed that MRG15 modulates the chromatin landscape of myogenic genes through interaction with MyoD, thereby facilitating transcriptional activation and differentiation. Our findings establish MRG15 as a critical epigenetic regulator that cooperates with MyoD to orchestrate chromatin remodeling, thereby promoting transcriptional activation of the myogenic program. Dysregulation of MRG15 may underlie impaired muscle regeneration during aging.

The precise ablation of specific cell lineages is crucial for functional studies in vivo. Conventional methods, like the Cre-dependent iDTR system, are constrained by the off-target effects and variable efficiency of single-recombinase approaches. Here, we present a novel Cdh5-RL-DTRGFP mouse model that requires both Dre and Cre recombinases to activate diphtheria toxin receptor (DTR) and GFP expression specifically in endothelial cells. This dual-recombinase logic ensures tight control over transgene expression. We demonstrate that diphtheria toxin administration in recombined mice leads to efficient endothelial cell ablation, resulting in severe vascular leakage, rapid organ failure, and mortality. The Cdh5-RL-DTRGFP line thus provides a robust and precise platform for the genetic dissection of endothelial cell function in physiological and pathological contexts.

Currently, effective treatments for skeletal muscle injury remain limited. The self-repair of skeletal muscle relies on the activation and differentiation of satellite cells (SCs), which fuse with damaged myofibers to form new fibers and thereby support muscle regeneration. However, in cases of severe injury, it is difficult for muscle tissue to fully restore its original structure and function, and its regenerative capacity is often markedly reduced. Thus, there is an urgent need to develop therapies that enhance muscle repair and restore physiological function. In this study, we investigated extracellular vesicles derived from neonatal mouse skeletal muscle (NMM-EVs), which are enriched in cargo from Pax7⁺ myogenic progenitor cells. We hypothesized that NMM-EVs could enhance SC activation and improve muscle regeneration following injury. Using glycerol-induced tibialis anterior (TA) muscle injury model, we evaluated the effects of intramuscular NMM-EV administration on skeletal muscle regeneration by histological, immunofluorescence, and functional analyses. In vivo, NMM-EVs significantly promoted skeletal muscle regeneration and functional recovery, upregulated Pax7 expression, increased the cross-sectional area and muscle mass of regenerated TA, and reduced fibrosis and fat infiltration. In vitro, NMM-EVs enhanced the proliferation and myogenic differentiation of mouse SCs and increased the expression of myogenic regulatory factors at both the mRNA and protein levels. In conclusion, this study demonstrates that NMM-EVs activate SCs within injured muscle, promote their proliferation and differentiation, and thereby accelerate injury repair and myofiber regeneration while attenuating fibrotic and adipogenic remodeling. These findings provide a scientific basis for the development of neonatal muscle-derived extracellular vesicle-based, cell-free therapeutic strategies for skeletal muscle injury.

Cardiac fibrosis following myocardial infarction (MI) is a critical determinant of progressive cardiac dysfunction, yet the underlying mechanisms driving this pathological process remain incompletely understood. Elucidating these regulatory pathways holds profound implications for improving post-MI prognosis.Our prior work demonstrated that chronic intermittent hypoxia (CIH) exacerbates cardiac fibrosis while modulating the expression of long non-coding RNA (lncRNA) nonnmmut065573 (tentatively designated LncRNA-IH) in cardiac tissues. Herein, we sought to determine the role of LncRNA-IH in post-MI cardiac fibrosis and its underlying mechanisms. Using a C57BL/6 mouse model of MI, we established a mouse model with cardiac-specific overexpression of LncRNA-IH to evaluate post-MI cardiac fibrosis. In vitro, primary cardiac fibroblasts (MCF) and the PA12 cell line were subjected to LncRNA-IH overexpression or siRNA-mediated knockdown, and cell proliferation and migration were assessed. Transcriptomic profiling was performed to characterize LncRNA-IH-induced changes in cardiac gene expression and signaling pathways, aiming to elucidate the molecular mechanisms involved.Results showed that CIH significantly exacerbated post-MI cardiac fibrosis, and LncRNA-IH was predominantly localized to cardiac fibroblasts. Cardiac-specific overexpression of LncRNA-IH in MI mice markedly exacerbated post-MI cardiac dysfunction and fibrosis. In vitro, LncRNA-IH overexpression significantly enhanced the proliferation and migration capacities of primary cardiac fibroblasts and PA12 cells, whereas these effects were abrogated by LncRNA-IH knockdown. Transcriptomic analysis revealed that LncRNA-IH elicited significant alterations in cardiac gene expression profiles, specifically activating the TGF-β1 signaling pathway and upregulating the expression of its downstream target, ZEB1.Collectively, our findings indicate that LncRNA-IH promotes cardiac fibroblast proliferation and migration, thereby exacerbating post-MI cardiac remodeling, at least in part through activation of the TGF-β1 signaling pathway. This study identifies LncRNA-IH as a potential therapeutic target for mitigating post-MI cardiac fibrosis and preserving cardiac function.

The placenta plays a pivotal role in human pregnancy, yet research into placental development has been hindered by limited access to early-stage embryos and ethical constraints. Although human trophoblast stem cells (hTSCs) have been established from blastocysts, deriving these cells efficiently from primed human pluripotent stem cells (hPSCs) remains challenging. Here, we developed a simplified and efficient strategy that enables direct, efficient conversion of primed hPSCs into stable, self-renewing hTSCs by transiently inhibiting the MEK/ERK signaling pathway using the inhibitor PD0325901 in a simplified basal medium. This approach significantly enhanced the generation of trophoblast cells expressing the critical trophoblast marker GATA3 and led to the establishment of homogeneous hTSC lines with robust capacities to differentiate into functional extravillous trophoblast (EVT) and syncytiotrophoblast (STB) lineages. Transcriptomic and chromatin accessibility analyses confirmed that these hTSCs closely resembled blastocyst-derived trophoblast cells and clearly differed from amnion lineages, confirming authentic trophoblast identity distinct from amnion. Additionally, precise modulation of WNT signaling activity was essential for optimal trophoblast induction efficiency, highlighting the importance of signaling equilibrium in trophoblast differentiation. Collectively, our optimized protocol offers an accessible and reproducible platform for modeling early placental development and understanding the pathogenesis of trophoblast-associated disorders in vitro.

Human umbilical cord mesenchymal stem cells (hUC-MSCs) have emerged as promising candidates for clinical applications in vascular disease therapy and in the in vitro modeling of vascular regeneration. However, the translational potential of hUC-MSCs requires direct differentiation into functional vascular lineage cells, particularly vascular endothelial cells (VECs) and endothelial progenitor cells (EPCs). A critical challenge is the lack of reliable sources that yield sufficient quantities of mature VECs/EPCs for therapeutic purposes. To address this limitation, we established an efficient protocol for generating VECs from hUC-MSCs. Preconditioning hUC-MSCs using small molecules with cytoprotective properties can enhance their potential for use in cell-based therapeutics. Through systematic screening, we identified CPP as a novel small chemical molecule that effectively induces the endothelial differentiation of hUC-MSCs. Remarkably, our CPP-based induction protocol achieved > 90% conversion to functionally competent VECs within 5 days, as evidenced by both in vitro assays and in vivo functional validation. Single-cell RNA sequencing (scRNA-seq) analysis further delineated the differentiation trajectory and confirmed the acquisition of endothelial-specific molecular signatures during lineage commitment. These findings establish CPP as a potent inducer of rapid endothelial differentiation, and provide mechanistic insights into stem cell fate determination.

Mesenchymal stromal cells (MSCs) possess well-described immunoregulatory properties, yet their capacity to drive regeneration in vertebrates is still debated and their mechanisms of action remain to be fully elucidated. In this study, we used zebrafish larvae, a highly regenerative vertebrate model to study the effects of MSC delivery on caudal fin fold regeneration and monitored macrophage dynamics through live imaging in fluorescent reporter lines. We found that MSCs enhanced fin regeneration by increasing the early recruitment of inflammatory (tnfa +) macrophages at 1-day-post-amputation (dpA), and accelerating resolution between 2 and 3 dpA. Given the established role of prostaglandin E2 (PGE2) in MSC-mediated immunoregulation, we examined its contribution using indomethacin, a cyclooxygenase inhibitor that suppresses PGE2 production in grafted MSCs. We observed that PGE2 inhibition abolished the pro-regenerative effect of MSCs and maintained elevated tnfa + macrophage levels. PGE2-inhibited MSCs were more susceptible to phagocytosis by both zebrafish and mammalian macrophages, while maintaining viability, indicating a loss of PGE2-mediated protection in treated cells. Together, these findings demonstrate that MSC-derived PGE2 is essential for MSC regenerative function by promoting MSC persistence and modulating macrophage behavior, highlight the zebrafish as a powerful in vivo platform to dissect stem cell-immune interactions and optimize MSC-based regenerative strategies.

Random-pattern skin flaps are widely employed in tissue reconstruction, however, their survival is frequently hindered by ischemia, leading to necrosis. Metabolic alterations have been implicated in playing critical roles in angiogenesis during tissue repair. Using RNA sequencing analysis in a mouse model, we identified significant disruptions in glutamine metabolism, which substantially impaired angiogenesis within random-pattern skin flaps. Although local glutamine repletion failed to alleviate ischemia, administering α-ketoglutarate (α-KG) markedly promoted angiogenesis, as evidenced at both gene and protein levels. In human umbilical vein endothelial cells,α-KG enhanced the stability of hypoxia-inducible factor (HIF-1) alpha through activation of the phosphoinositide 3-kinase (PI3K)-Akt signaling pathway. Notably, α-KG treatment improved flap viability by augmenting blood perfusion, an effect correlated with upregulation of vascular endothelial growth factor expression. Together, these results reveal a novel mechanism by which α-KG enhances random-pattern skin flap viability via promoting angiogenesis through the PI3K/Akt/HIF-1α pathway, offering promising therapeutic insights for improving flap survival.