Stem cells and development最新文献

Mesenchymal stromal cells have shown promising effects in the treatment of immune thrombocytopenia. However, the underlying mechanisms are not fully understood. In this study, we investigated the therapeutic effects of human bone marrow mesenchymal stromal cells (hBMSCs) and analyzed their unique role in regulating the M1/M2 macrophage ratio. We established a passive immune thrombocytopenia (ITP) mouse model and showed that there was a significant M1/M2 imbalance in ITP model mice by assessing the M1/M2 ratios in the liver, spleen, and bone marrow; we observed excessive activation of M1 cells and decreased M2 cell numbers in vivo. We have shown that systemic infusion of hBMSCs effectively elevated platelet levels after disease onset. Further analysis revealed that hBMSCs treatment significantly suppressed the number of proinflammatory M1 macrophages and enhanced the number of anti-inflammatory M2 macrophages; in addition, the levels of proinflammatory factors, such as interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF-α), were significantly decreased in vivo, while the levels of the anti-inflammatory factor interleukin-10 (IL-10) were increased. In conclusion, our data suggest that hBMSCs treatment can effectively increase platelet counts, and the mechanism is related to the induction of macrophage polarization toward the anti-inflammatory M2 phenotype and the decrease in proinflammatory cytokine production, which together ameliorate innate immune disorders.

The parathyroid gland plays an essential role in mineral and bone metabolism. Cultivation of physiological human parathyroid cells has yet to be established and the method by which parathyroid cells differentiate from pluripotent stem cells remains uncertain. Therefore, it has been hard to clarify the mechanisms underlying the onset of parathyroid disorders, such as hyperparathyroidism. In this study, we developed a new method of parathyroid cell differentiation from human induced pluripotent stem (iPS) cells. Parathyroid cell differentiation occurred in accordance with embryologic development. Differentiated cells, which expressed the parathyroid hormone, adopted unique cell aggregation similar to the parathyroid gland. In addition, these differentiated cells were identified as calcium-sensing receptor (CaSR)/epithelial cell adhesion molecule (EpCAM) double-positive cells. Interestingly, stimulation with transforming growth factor-α (TGF-α), which is considered a causative molecule of parathyroid hyperplasia, increased the CaSR/EpCAM double-positive cells, but this effect was suppressed by erlotinib, which is an epidermal growth factor receptor (EGFR) inhibitor. These results suggest that TGF-α/EGFR signaling promotes parathyroid cell differentiation from iPS cells in a similar manner to parathyroid hyperplasia.

Mesenchymal stromal cells (MSCs) are a promising cell source for cartilage tissue regeneration in animals and humans but with large interdonor variation in their in vitro chondrogenic differentiation potential. Underlying molecular mechanisms responsible for culture-expanded MSC heterogeneity remain poorly understood. In this study, we sought to identify variations in microRNA (miRNA) signatures associated with cultured equine MSC chondrogenic differentiation potential from different donors. Neocartilage tissue generated from equine cord blood-derived MSCs was categorized as having either high or low chondrogenic potential (LCP) based on their histological appearance and quantification of glycosaminoglycan deposition. Using next-generation sequencing, we identified 30 differentially expressed miRNAs among undifferentiated MSC cultures that corresponded with their chondrogenic potential. Of note, MSCs with LCP upregulated miR-146a and miR-487b-3p, which was also observed by quantitative real-time polymerase chain reaction. Our findings suggest that miRNA profiling of equine MSC cultures may have prognostic value in selecting MSC donors with regard to their chondrogenic differentiation potential.

Retinitis pigmentosa (RP) is a prevalent inherited retinal degenerative disease resulting from photoreceptor and pigment epithelial apoptosis. The Rhodopsin (RHO) is the most commonly associated pathogenic gene in RP. However, RHO mutations (c.512C>T P171L) have been infrequently reported, and the RP pathogenesis caused by these mutations remains unclear. The objective of this study was to investigate the impact of RHO (c.512C>T P171L) mutation on retinal cell differentiation and elucidate the underlying mechanisms of RP. An effective retinal organoid induction scheme for inhibiting the Wnt signaling pathway was selected for further experiments, and the established cell line chHES-406 was demonstrated to be heterozygous for RHO c.512C>T, with a normal karyotype and pluripotency potential. Furthermore, the development of chHES-406 organoids may be delayed, and apoptosis detection and co-localization revealed that chHES-406 organoids had more apoptotic cells than chHES-90 in the outer nuclear layer (ONL), mutant RHO protein was mislocalized in the endoplasmic reticulum (ER), and stress-related and apoptotic gene expression increased. Overall, our study elucidated a possible mechanism by which ER stress caused by RHO P171L protein mislocalization may lead to ONL cell apoptosis.

Glucocorticoids are common anti-inflammatory factors; however, they have been reported to have side effects that delay the wound healing process. In a previous study, we found that mesenchymal stem cells isolated from the adipose tissue of patients with long-term glucocorticoid treatment (sAT-MSC) showed impaired wound healing ability due to the downregulation of SDF-1. In this study, we aimed to clarify the mechanisms by which SDF-1 is regulated in sAT-MSC by focusing on the roles of hypoxia-inducible factors (HIFs). Our data suggested that sAT-MSC showed impairment of HIF-1α and the upregulation of HIF-2α. Notably, HIF-2α impairment resulted in the compensatory overexpression of HIF-1α and its target gene SDF-1, which improved the wound healing ability of sAT-MSC. In addition, using knockdown/knockout heterozygous HIF-2α kd/null mice (kd/null), the functions of HIF-2α in the ischemic wound healing process were clarified. With a 50% reduction in the expression of HIF-2α, kd/null mice showed significantly induced wound healing effects, which are involved in the promotion of the inflammatory phase. Specifically, kd/null mice showed the compensatory overexpression of HIF-1α, which upregulated the expression of SDF-1 and enhanced the recruitment of inflammatory cells, such as neutrophils. Our study highlighted the novel function of HIF-2α in the inflammation phase of the wound healing process through the HIF-1α/SDF-1 axis, suggesting that the physiological state of the impaired expression of HIF-2α is a new concept for wound therapy.

As the body ages, it experiences a gradual decline in the functioning of cells, tissues, and systems, which eventually leads to dysfunction and increased susceptibility to disease. At the cellular level, a reduction in the activity or number of stem cells is an important feature of cell senescence, and such changes may also directly drive the aging of the organism. Thus, finding ways to prevent or even reverse stem cell senescence holds promise for the development of aging therapies in tissues and organisms. This review discusses the relationship between changes in stem cell senescence, tissues aging, and related diseases, focusing on four categories of tissue stem cells: hematopoietic stem cells, mesenchymal stromal/stem cells (MSCs), intestinal stem cells, and muscle stem cells.

The mature brain contains an incredible number and diversity of cells that are produced and maintained by heterogeneous pools of neural stem cells (NSCs). Two distinct types of NSCs exist in the developing and adult mouse brain: Glial Fibrillary Acidic Protein (GFAP)-negative primitive (p)NSCs and downstream GFAP-positive definitive (d)NSCs. To better understand the embryonic functions of NSCs, we performed clonal lineage tracing within neurospheres grown from either pNSCs or dNSCs to enrich for their most immediate downstream neural progenitor cells (NPCs). These clonal progenitor lineage tracing data allowed us to construct a hierarchy of progenitor subtypes downstream of pNSCs and dNSCs that were then validated using single-cell transcriptomics. Further, we identify Nexn as required for neuronal specification from neuron/astrocyte progenitor cells downstream of rare pNSCs. Combined, these data provide single-cell resolution of NPC lineages downstream of rare pNSCs that likely would be missed from population-level analyses in vivo.

Trophoblast stem (TS) cells were first isolated from the mouse placenta; however, little is known about their maintenance and niche in vivo. TS cells, like other stem cells, have a unique microenvironment in which the extracellular matrix (ECM) is a component. Placental pathology is associated with ECM change. However, how these changes and the individual ECM components impact the maintenance or differentiation of TS cells has not been established. This study identified which ECM component(s) maintain the greatest expression of markers associated with undifferentiated mouse trophoblast stem (mTS) cells and which alter the profile of markers of differentiation based on mRNA analysis. mTS cells cultured on individual ECM components and subsequent quantitative polymerase chain reaction analysis revealed that laminin promoted the expression of markers associated with undifferentiated TS cells, fibronectin promoted gene expression associated with syncytiotrophoblast (SynT) layer II cells, and collagen IV promoted the expression of genes associated with differentiated trophoblast. To investigate whether pathological placental ECM influenced the expression of genes associated with different trophoblast subtypes, the mouse model of streptozotocin (STZ)-induced pancreatic β cell ablation and diabetes was used. Female mice administered STZ (blood glucose ≥300 mg/dL) or control (blood glucose ≤150 mg/dL) were mated. Placental pathology at embryonic day (E)14.5 was confirmed with reduced fetal blood space area, reduced expression of the pericyte marker αSMA, and decreased expression of ECM proteins. mTS cells cultured on ECM isolated from STZ placenta were associated with reduced expression of undifferentiated mTS markers and increased expression of genes associated with terminally differentiated trophoblast [Gcm-1 and SynA (SynT) and junctional zone Tpbpa and Prl2c2]. Altogether, these results support the value of using ECM isolated from the placenta as a tool for understanding trophoblast contribution to placental pathology.

The alveolar bone marrow mesenchymal stem cells (ABM-MSCs) play an important role in oral bone healing and regeneration. Insulin is considered to improve impaired oral bones due to local factors, systemic factors and pathological conditions. However, the effect of insulin on bone formation ability of ABM-MSCs still needs to be elucidated. The aim of this study was to determine the responsiveness of rat ABM-MSCs to insulin and to explore the underlying mechanism. We found that insulin promoted ABM-MSCs proliferation in a concentration-dependent manner, in which 10^-6 M insulin exerted the most significant effect. 10^-6 M insulin significantly promoted the type I collagen (COL-1) synthesis, alkaline phosphatase (ALP) activity, osteocalcin (OCN) expression, and mineralized matrix formation in ABM-MSCs, significantly enhanced the gene and protein expressions of intracellular COL-1, ALP, and OCN. Acute insulin stimulation significantly promoted insulin receptor (IR) phosphorylation, IR substrate-1 (IRS-1) protein expression, and mammalian target of rapamycin (mTOR) phosphorylation, but chronic insulin stimulation decreased these values, while inhibitor NT219 could attenuate these responses. When seeded on β-tricalcium phosphate (β-TCP), ABM-MSCs adhered and grew well, during the 28-day culture period, ABM-MSCs+β-TCP +10^-6 M insulin group showed significantly higher extracellular total COL-1 amino-terminus prolongation peptide content, ALP activity, OCN secretion, and Ca and P concentration. When implanted subcutaneously in severe combined immunodeficient mice for 1 month, the ABM-MSCs+β-TCP +10^-6 M insulin group obtained the most bone formation and blood vessels. These results showed that insulin promoted the proliferation and osteogenic differentiation of ABM-MSCs in vitro, and enhance osteogenesis and angiogenesis of ABM-MSCs in vivo. Inhibition studies demonstrated that the insulin-induced osteogenic differentiation of ABM-MSCs was dependent of insulin/mTOR signaling. It suggests that insulin has a direct anabolic effect on ABM-MSCs.