Differentiation最新文献

Piezo1 and Piezo2 are recently discovered mechanosensory ion channels. Piezo channels transduce mechanical stimulation into cellular signaling in a variety of tissues and organ systems. The functional roles of Piezo1 and Piezo2 have been revealed in both developmental and physiological scenarios by using mouse genetic models. Mechanotransduction by Piezo1 channels regulates osteoblast/osteocyte activity and, thus, strengthens the skeleton enabling it to adapt to a wide range of mechanical loadings. Deletion of the Piezo1 gene in the developing skeleton causes bone malformations that lead to spontaneous bone fractures, while inactivity of Piezo1 in adulthood results in osteoporosis. Furthermore, Piezo2 channels in sensory neurons might provide another route of skeletal regulation. Piezo channels also regulate the proliferation and differentiation of various types of stem cells. PIEZO1 and PIEZO2 mutations and channel malfunctions have been implicated in an increasing number of human diseases, and PIEZO channels are currently emerging as potential targets for disease treatment. This review summarizes the important findings of Piezo channels for skeletal development and homeostasis using the mouse genetic model system.

The mandible is an important part of the craniofacial skeleton. Mandibular development is complex and involves multiple signaling pathways. These signaling pathways participate in a complex regulatory mechanism to regulate mandibular growth. The function of hedgehog signaling has previously been shown to be crucial for mandibular arch development. We treated pregnant ICR mice with the hedgehog pathway inhibitor vismodegib by oral gavage to establish a micrognathia model, which was mandible development defective. Compared to control, this model exhibited reduced mesenchymal cell proliferation and increased apoptosis. The development of the Meckel's cartilage and the condensations of mesenchymal cells were delayed by approximately one day in treated embryos. These results reveal that Smoothened may have shaped the mandible during mandibular growth by ensuring cell survival, proliferation, and development of Merkel's cartilage.

Vascular smooth muscle cell (SMCs) differentiation is critical for cardiovascular development, but the mechanisms remain largely unknown. The overall aim of this study was to investigate the functional impact and mechanism of cellular repressor of E1A-stimulated genes (CREG) in SMC differentiation. Two embryonic stem cell (ESC) models were generated (1) the overexpression of CREG (CREG-OE), by transfection with Pcreg-IRECS2-EGFP vector, and (2) the knockout of CREG, by transfection with CREG shRNA (CREG-KO). Interesting, SMC-marker levels (SM α-actin, SM22, Calponin, and SM-MHC) dramatically increased in CREG-OE ESCs into the SMC while significantly decreased in CREG-KO ESCs during differentiation. After 14 days, and calcium ion concentrations in angiotensin II-stimulated embryoid bodies were increased in CREG-OE ESCs but reduced in CREG-KO ESCs. Consistently, the contractile capacity of SMC from CREG-OE ESC was increased, while the contractile capacity of SMC CREG1 from CREG-KO ESCs was significantly reduced. Furthermore, we demonstrated that CREG promotes differentiation of ESCs to SMCs and maturation of their function through the transforming growth factor-β -smad2/3 pathway.

A pre-existent gene expression program at the basis of cell differentiation and development is often assumed in the current scientific literature. Historically this conception is traced to the nineteen sixties of the last century, when various influential papers and scientific personalities imprinted their view drawing inspiration from informatics. The accepted model is that in the presence of certain external and/or internal signals, a cell initiates a pre-determined program of gene expression by which it becomes differentiated. Authors generally do not question the evidence for the existence of such a program. Here I review different aspects and consequences of this model to conclude that it is completely at odds with the literature of the last decades, which has given us a splendid view of the dynamics of the living cell as an auto-organizing complex unit that is far away from thermodynamical equilibrium. In this view there is no place for programs.

Mouse embryonic stem cells (mESCs) are characterized by self-renewal and pluripotency and can undergo differentiation into the three germ layers (ectoderm, mesoderm, and endoderm). Melanoma-associated antigen D1 (Maged1), which is expressed in all developing and adult tissues, modulates tissue regeneration and development. In the present study, we examined the expression and function of Maged1 in mESCs. Maged1 protein and mRNA expression increased during mESC differentiation. The pluripotency of mESCs was significantly reduced through extracellular signal-regulated kinase 1/2 phosphorylation upon knockdown of Maged1, and through G₁ cell cycle arrest during cell division, resulting in significantly reduced mESC proliferation. Moreover, the diameter of the embryoid bodies was significantly reduced, accompanied by increased levels of ectodermal differentiation markers and decreased levels of mesodermal and endodermal differentiation markers. Maged1-knockdown mESC lines showed significantly reduced teratoma volumes and inhibition of teratoma formation in nude mice. Additionally, we observed increased ectodermal markers but decreased mesodermal and endodermal markers in teratoma tissues. These findings show that Maged1 affects mESC pluripotency, proliferation, cell cycle, and differentiation, thereby contributing to our understanding of the basic molecular biological mechanisms and potential roles of Maged1 as a regulator of various mESC properties.

Idiopathic pulmonary fibrosis (IPF) is a chronic, progressive, and fatal lung disease that is characterized by enhanced changes in stem cell differentiation and fibroblast proliferation. Lung resident mesenchymal stem cells (LR-MSCs) are important regulators of pathophysiological processes including tissue repair and inflammation, and evidence suggests that this cell population also plays an essential role in fibrosis. Our previous study demonstrated that Wnt/β-catenin signaling is aberrantly activated in the lungs of bleomycin-treated mice and induces myofibroblast differentiation of LR-MSCs. However, the underlying correlation between LR-MSCs and the Wnt/β-catenin signaling remains poorly understood. We found that Wnt8b was highly expressed by LR-MSCs undergoing myofibroblast differentiation. In vitro, Wnt8b promoted LR-MSCs differentiate into myofibroblasts via activating Wnt/β-catenin signaling. Moreover, siRNA-mediated inhibition of Wnt8b prevented Transforming growth factor (TGF)-β1-induced myofibroblast differentiation of LR-MSCs in vitro and ameliorated pulmonary fibrotic lesions. Our study identified Wnt proteins and Wnt/β-catenin signaling in pulmonary fibrosis in vitro and in vivo, and highlighted Wnt8b as a potential therapeutic target in pulmonary fibrosis. Moreover, these finding might provide a new perspective in the development of treatment strategies for IPF.

Cancer immunotherapy using dendritic cells (DCs) able to induce specific immune responses to naïve T lymphocytes raises great research interest. However, the extremely complex and expensive methods used to produce DCs, combined with the limited number of autologous DCs in the circulation make any application almost impossible. Aim of the study is the development of an optimized and simplified system to easily produce in large scale cord blood-derived DCs, loaded with common tumor antigens, capable of promoting controlled Th1 immunoresponses following clinically approved maturation with vaccines. CD34+cells cultured in the presence of a cytokine cocktail in miniPERM® bioreactors and the generated DCs were matured using anti-flu vaccines. Autologous T cells plated with DCs pulsed with overlapping peptides CEA and WT1 for multiple stimulations. 200 billion of myeloid DCs were produced and matured in just 8 h in bioreactors, presenting an increased expression of the co-stimulatory molecules and also high levels of Th1 related cytokines. Upon just the 2nd stimulation, the T cells exhibited specificity following stimulation with the CEA/WT1 peptides and strong cytotoxic capacity in co-culture with a colorectal cancer (CRC)-cell line. The high produced doses of DCs, easily maturated with clinically approved agents, and capable of priming specific T cells, could potentially strengthen the further progress in DCs-mediated cancer immunotherapy field.

DNA methylation of cytosine bases is a major epigenetic modification that regulates gene expression and vertebrate development. The ten-eleven translocation (TET) enzymes oxidize 5-methylcytosine (5mC) to 5-hydroxymethylcytosine (5hmC), and active DNA demethylation influences gene expression specific to each developmental stage, although recent reports have shown that TET also has a non-catalytic function. In fetal mice, the epithelium in the submandibular gland (SMG) buds as a derivative of the oral cavity at embryonic day 11 (E11) and, by E15, it begins to differentiate into the salivary epithelium, which expresses water-channel aquaporin 5 (AQP5). The functional differentiation of the SMG epithelium can be regulated epigenetically, but how TET enzymes contribute is largely unknown. Here, we used several techniques, including hydroxymethylated DNA immunoprecipitation qPCR and histological analysis, to examine the changes in 5hmC levels and AQP5 and TET expression during SMG development. We found that 5hmC levels and AQP5 expression increased in the E15 SMG epithelium, while TET2 expression in the terminal buds decreased at E15. In agreement with the in vivo observations, Tet2 inhibition ex vivo led to the upregulation of AQP5 expression in terminal buds of the SMG epithelium. These results suggest that the downregulation of TET2 expression at E15 is a critical epigenetic event that establishes the epithelial fate for functional SMGs during development.

Claudins are a family of tight junction proteins expressed in epithelial tissues during development and in postnatal life. We hypothesized that claudins are required for branching morphogenesis in the developing chick lung. To test this hypothesis, we exposed cultured chick lung explants at embryonic day 5 to a truncated non-toxic form of the Clostridium perfringens enterotoxin known as C-CPE that removes C-CPE-sensitive claudins from tight junctions. Using in situ hybridization and immunofluorescence studies, we established that only one C-CPE-sensitive claudin, Claudin-3, was expressed in the chick lung at this stage. C-CPE treated lung explants did not exhibit any defect in lung branching compared to controls. However, they did exhibit a significantly smaller lumen area, suggesting that paracellular permeability was perturbed. The decrease in lumen area was associated with a loss of Claudin-3 expression within tight junctions of the respiratory epithelium and an increase in permeability of the respiratory epithelium. When C-CPE-treated lung explants were treated with forskolin, lumen area was restored. In summary, removal of a sealing claudin, Claudin-3, from tight junctions in embryonic lung epithelium results in a decrease in lumen area and in hydrostatic pressure needed for lung development.

Bone is a dynamic and tough connective tissue that undergoes constant remodeling throughout life. Bone-forming osteoblasts respond to various hormones, cytokines, and growth factors, and synthesize extracellular matrix components. Runx2 (Runt-related transcription factor 2), a bone transcription factor, is essential for ossification by stimulating the expression of osteoblast differentiation marker genes, including type I collagen, alkaline phosphatase, and osteocalcin. Coactivators, such as p300, CBP (CREB-binding protein), and PCAF (p300/CBP associated factor) tightly regulate osteoblast differentiation via Runx2. There is growing evidence indicating the role of p300, which possesses histone acetyltransferase (HAT) activity, in regulating histones and transcription factors such as Runx2 during osteoblast differentiation. In this review, we aim to delineate the role of p300 at the molecular level, emphasizing the importance of its HAT activity during osteoblast differentiation. Furthermore, this review intends to highlight the regulation of p300 at multiple levels, including post-translational and ncRNAs, that might exert an indirect influence on bone formation.