Stem Cell Reports最新文献

Oligodendrocyte precursor cells (OPCs) are highly adaptable, engaging in diverse functions beyond myelination. However, how OPCs adjust their roles after ischemic stroke and contribute to recovery remains largely unknown. To address this gap, we constructed a "transient middle cerebral artery occlusion (tMCAO) atlas" by integrating mouse single-cell RNA sequencing (scRNA-seq) datasets and combined it with ex vivo OPC cultures and in vivo cell transplantation experiments. This approach revealed the emergence of "angiogenic" OPCs in the subacute phase and "oligogenic" OPCs in the chronic phase, driven by distinct levels of hypoxia-severe hypoxia inducing angiogenic OPCs and mild hypoxia promoting oligogenic OPCs. Ex vivo, severe hypoxic preconditioning faithfully induced angiogenic OPCs, and their intravenous transplantation enhanced angiogenesis and improved recovery in tMCAO mice. These findings highlight "oxygen tone" as a key regulator of OPC dynamic adaptation after ischemic stroke, offering a promising strategy to harness OPCs for stroke cell therapy.

Functional integration of transplanted cells with host tissue remains a major challenge in cell-based therapies for tissue damage in organs with complex structures, such as exocrine glands. In this study, we investigated whether salivary gland organoids derived from human induced pluripotent stem cells (hiPSCs) could be integrated into injured salivary glands using cell sheet engineering. Cell sheet engineering has demonstrated therapeutic potential in a range of organs, including the heart, retina, and lungs. We found that hiPSC-derived salivary gland organoids contain long-term maintainable progenitor cells, and the resulting cell sheets exhibited heterogeneity, including acinar, ductal, and myoepithelial cells. Furthermore, transplantation of the organoid-derived salivary gland cell sheets into immunodeficient mice resulted in partial integration with the host salivary ducts, leading to the formation of structures that included xenogeneic chimeric ducts. These findings suggest that salivary gland cell sheet transplantation represents a promising strategy for functional salivary gland regeneration.

A pivotal question at the heart of stem cell research is how faithful cellular models recapitulate human tissues. Skeletal muscle, the largest organ in the human body, has been modeled by various in vitro systems. Here, we sought to delineate the state-of-the-art of muscle models by performing a large-scale analysis of transcriptome datasets, covering over 400 samples across 39 studies, including bulk and single-cell RNA sequencing of 2D and 3D models and their in vivo counterparts. By comparing these models to in vivo muscle, we highlighted failed upregulation of myogenic factors and retention of epigenetic memory from the in vitro source material. We featured differences in lipid metabolism and depletion of multiple fibroblast growth factor (FGF) ligands in the in vitro models. Finally, we revealed model-dependent variation in myogenic progenitors. Our analyses highlight targetable processes to improve the models while paving the way for similar studies on other cell types.

Inner ear organoid development-from germ layer to otic vesicle (OV) formation-relies on timed chemical cues to recapitulate major signals in vivo. In contrast, later stages of differentiation-from OV to organoid formation-are self-guided, even though these stages are modulated by several key morphogens in vivo. We sought to elucidate additional morphogens that might improve culture efficiency and influence cell fate decisions. Using a whole-transcriptomic approach, we identified major differences in native and stem-cell-derived OVs related to anterior-posterior patterning and retinoic acid (RA) signaling. Increasing the level of RA during OV formation in these cultures modulated organoid efficiency, increased nonsensory markers, decreased sensory markers, and decreased hair cell production. The organoid culture platform mimics the exquisite RA sensitivity found in normal inner ear development and provides a tunable system for generating sensory and nonsensory cell types in inner ear organoids.

Methyl-CpG-binding protein 2 (MECP2)/Rett syndrome is characterized by a postnatal loss of neurophysiological function and regression of childhood development. While Rett neurons have been described as showing elevated senescence and P53 activity, here we show that molecular and physiological dysfunction in neurons lacking MECP2 is triggered by elevated DNA damage. Using human induced pluripotent stem cell (hiPSC)-derived isogenic lines, we find that MECP2 directly interacts with members of the DNA repair machinery, including PARP1. Here, we present evidence that MECP2 also regulates PARP1 activity, and restoration of PARP1 activity in MECP2-null neurons can reverse DNA damage, senescence, dendritic branching defects, and metabolic dysfunction. These data from a human disease-in-a-dish model system support the notion that dysfunction in Rett syndrome neurons could be caused by changes in PARP activity.

Excitatory/inhibitory (E/I) balance is thought to play a key role in cortical activity development. We modeled an in vitro cortical network deployed of the inhibitory neurons normally migrating from the ventral telencephalon and implemented ventral telencephalic (VT) cultures and co-cultures with mixed proportions of dorsal telencephalic (DT) and VT neurons, containing distinct proportions of inhibitory neurons. Interestingly, these pure and mixed cultures developed different patterns of spontaneous activity and functional connectivity. Our findings highlighted a critical role for the inhibitory component in developing correlated network activity. Unexpectedly, networks with 7% of parvalbumin (PV)⁺ neurons were not able to generate appreciable network burst activity due to the development of a strong network inhibition, despite their lowest E/I ratio. Our observations support the notion that an optimal ratio of PV⁺ neurons during cortical development is essential for the establishment of local inhibitory networks capable of generating and spreading correlated activity.

Ectopic expression of proteins in human pluripotent stem cells (hPSCs) is highly desirable as a research tool and important for clinical translation. However, genetically engineering hPSCs for long-term overexpression of proteins remains inefficient, labor-intensive, and plagued by epigenetic silencing, necessitating dedication of significant resources, and entailing laborious workflows. To address these limitations, we report the development of XPRESSO (expedited persistent and robust engineering of stem cells with sleeping beauty for overexpression), a modular "anti-silencing" transposon vector, which we have combined with a highly efficient and accessible methodology for the rapid generation of genetically modified hPSC lines in a gene-independent manner. Using this method, we successfully generated dozens of stable hPSC lines with robust and continuous functional expression of optogenetic proteins, Cas9, shRNA, and a calcium indicator in both undifferentiated and differentiated (cardiomyocyte and neuronal) cells.

This study investigated the role of miR-22-3p/ESR1 axis in osteoporosis (OP) pathogenesis. Bioinformatics analysis of OP datasets and patient bone marrow samples revealed significant upregulation of miR-22-3p accompanied by downregulation of ESR1. Mechanistic validation via dual-luciferase reporter assays, RNA pull-down, and molecular docking confirmed that miR-22-3p directly targets and suppresses ESR1 expression. Functional in vitro assays in human bone marrow mesenchymal stem cells (hBMSCs) demonstrated that miR-22-3p overexpression accelerated both cellular senescence (CS) and adipogenic differentiation. Notably, this effect was reversed by ESR1 overexpression. In an aged mouse model, local intra-bone marrow administration of a miR-22-3p inhibitor effectively reduced bone marrow mesenchymal stem cell (BMSC) senescence, improved bone microstructure, and attenuated OP progression. These findings establish that the miR-22-3p-ESR1 regulatory axis critically drives OP development by coordinately promoting CS and adipogenic differentiation while suppressing osteogenesis. This pathway provides a promising mechanistic foundation for future therapeutic strategies targeting OP.

Carriers of two apolipoprotein L1 gene risk variants (RVs), termed G1 and G2, are at increased risk for chronic kidney disease. This study utilized induced pluripotent stem cells (iPSCs) derived from two patients homozygous for G1 and G2 to model human apolipoprotein L1 (APOL1)-mediated kidney disease (AMKD) in kidney organoids. Single-cell transcriptomic analysis and immunofluorescence imaging showed APOL1 upregulation in podocytes after interferon-gamma (IFN-γ) treatment. Transcriptomics and spatial dynamic metabolomics demonstrated a significant reduction in oxidative phosphorylation and tricarboxylic acid (TCA) cycle activity, along with upregulation of glycolysis and hypoxia signaling in RV podocytes. Isolated RV glomeruli exhibited no increase in maximal respiration rate following IFN-γ treatment, while iPSC-derived RV podocytes displayed a reduced number of mitochondrial branches and shorter branch length. This model presents early metabolic reprogramming of RV podocytes upon inflammatory injury and compelling evidence that mitochondrial dysfunction plays a pivotal role in the early pathophysiology of AMKD.

Human induced pluripotent stem cell (iPSC)-derived neurons are often heterogeneous, posing challenges for disease modeling and cell therapy. We previously developed single-cell glycan and RNA sequencing (scGR-seq) to analyze the glycome and transcriptome simultaneously. Here, we applied scGR-seq to examine heterogeneous populations of human iPSC-derived neurons. We identified four subpopulations: mature neurons, immature neurons, undifferentiated neural progenitor cells (undiffNPCs), and mesenchymal cells (MCs). Lectin-binding patterns indicated high α1,3-fucose expression in undiffNPCs. MCs exhibited strong binding of a poly-LacNAc-recognizing lectin (rLSLN) and high expression of B3GNT2, a poly-LacNAc synthetic enzyme. Pseudotime analysis revealed that a subpopulation of NPCs acquired mesenchymal features and differentiated into MCs. Immunocytochemistry confirmed the specific detection of undiffNPCs and MCs using anti-Lewis X (α1,3-fucosylated glycan) antibodies and rLSLN. Beyond identifying cell heterogeneity, scGR-seq enables the discovery of glycan markers and detection probes for iPSC-derived cells, aiding in their further cell processing and manipulation.