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Even the efficacy of substrate and mechanical stimuli in addition to biochemical cues have been recognized in many studies of stem cell differentiation, few studies have been reported on the differentiation into esophageal epithelial cells. Therefore, the aim of this study was set to propose a method of differentiating stem cells into esophageal epithelial cells according to biochemical reagent concentration, substrate properties, and mechanical forces. After the concentration of all-trans retinoic acid was determined as 5 μM by a baseline experiment, the degree of differentiation was compared in three different kinds of substrates: cover glass, polyurethane (PU) membrane, and electrospun PU sheet (ePU). Then, on the substrate showing the more positive results, that is, ePU, two types of mechanical forces, intermittent hydrostatic pressure (IHP), and shear stress (SS), were applied individually at different magnitudes for the latter 7 days of an overall incubation period of 14 days. Following various biological assays, the lower IHP (50 mmHg) resulted in greater positive effects than the others. Even with cessation of the mechanical force, the relevant markers were remarkably increased. Although the range of factors regulating differentiation was limited, this study nonetheless demonstrated the combinational effects of mechanical force along with substrate type for the first time in related studies. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 107A: 552-560, 2019., (© 2018 Wiley Periodicals, Inc.)

Sirtuin 6 (SIRT6) is a NAD-dependent deacetylase involved in lifespan regulation. To evaluate the effect of SIRT6 on osteogenesis, rat bone marrow mesenchymal stem cells (rBMSCs) with enhanced or reduced SIRT6 function were developed. We observed that SIRT6 knockdown significantly reduced the mRNA levels of several key osteogenic markers in vitro, including alkaline phosphatase (ALP), Runt-related transcription factor 2 (RUNX2), and osteocalcin, while overexpression of SIRT6 enhanced their expression. Additionally, SIRT6 knockdown activated nuclear factor-κB (NF-κB) transcriptional activity and upregulated the expression of acetyl-NF-κB p65 (Lys310). The decreased osteogenic differentiation ability of rBMSCs could be partially rescued by the addition of NF-κB inhibitor BAY 11-7082. Furthermore, SIRT6 overexpression in rBMSCs combined with the use of collagen/chitosan/hydroxyapatite scaffold could significantly boost new bone formation in rat cranial critical-sized defects, as determined by microcomputed tomography and histological examination. These data confirm that SIRT6 is mainly located in the nuclei of rBMSCs and plays an essential role in their normal osteogenic differentiation, partly by suppressing NF-κB signaling., (© 2014 AlphaMed Press.)

Background: We evaluated the outcome of esophageal reconstructions using tissue‐engineered scaffolds. Method: Partial esophageal defects were reconstructed with the following scaffolds; animals were grouped (n = 7 per group) as follows: (a) normal rats; (b) rats implanted with three‐dimensional printing (3DP) polycaprolactone (PCL) scaffolds; (c) with human adipose‐derived mesenchymal stem cell (ADSC)‐seeded 3DP PCL scaffolds; (d) with polyurethane (PU)‐nanofiber(Nf) scaffolds; and (e) with ADSC‐seeded PU‐Nf scaffolds. Results: The esophageal defects were successfully repaired; however, muscle regeneration was greater in the 3DP PCL + ADSC groups than in the PU‐Nf + ADSC groups (P <.001). Regeneration of the epithelium was greater in PU‐Nf and PU‐Nf + ADSC groups than in the 3DP PCL and 3DP PCL + ADSC groups (P <.001). Conclusion: A tendency for more re‐epithelization was observed with the PU‐Nf scaffolds, while more muscle regeneration was achieved with the 3DP PCL scaffolds. [ABSTRACT FROM AUTHOR]

Yes‐associated protein 1 (YAP1) transcriptional coactivator has recently been identified to regulate skeletal lineage cell differentiation and bone development. However, the role and molecular mechanisms of YAP1 in the regulation of osteoblastic differentiation remains to be elucidated. In this study, we demonstrated that YAP1 expression was increased during osteogenic differentiation of rat bone mesenchymal stem cells and MC3T3‐E1. YAP1 overexpression MC3T3‐E1 showed increased expression of osteogenesis markers, such as runt‐related transcription factor 2, osteocalcin, and osteopontin, as well as alkaline phosphatase and alizarin red staining. Conversely, YAP1 knockdown significantly suppressed MC3T3‐E1 osteoblastic differentiation. Mechanistically, we found that YAP1 overexpression upregulated the mRNA and protein expression of the inhibitor of differentiation/DNA binding 1 (ID1), which was contrary to the results of YAP1‐knockdown group. Moreover, the early osteogenic differentiation of MC3T3‐E1 cells was enhanced by ID1 overexpression. Furthermore, transient transfection with exogenous ID1 overexpression plasmid completely recaptured the decreased effects of YAP1 knockdown on MC3T3‐E1 cell differentiation. In addition, β‐catenin and AMP‐activated protein kinase signaling pathways participated in YAP1 regulation processes. Taken together, our study suggests that YAP1 is a crucial modulator of osteoblast differentiation in vitro, and provides insight into the mechanism by which YAP1 regulates osteoblast differentiation. [ABSTRACT FROM AUTHOR]

The roles of mitochondria in various physiological functions of vascular endothelial cells have been investigated extensively. Morphological studies in relation to physiological functions have been performed. However, there have been few reports of morphological investigations related to stem cell differentiation. This was the first morphological study of mitochondria in relation to endothelial differentiation and focused on quantitative analysis of changes in mitochondrial morphology, number, area, and length during differentiation of human mesenchymal stem cells (hMSCs) into endothelial-like cells. To induce differentiation, we engaged vascular endothelial growth factors and flow-induced shear stress. Cells were classified according to the expression of von Willebrand factor as hMSCs, differentiating cells, and almost fully differentiated cells. Based on imaging analysis, we investigated changes in mitochondrial number, area, and length. In addition, mitochondrial networks were quantified on a single-mitochondrion basis by introducing a branch form factor. The data indicated that the mitochondrial number, area per cell, and length were decreased with differentiation. The mitochondrial morphology became simpler with progression of differentiation. These findings could be explained in view of energy level during differentiation; a higher level of energy is needed during differentiation, with larger numbers of mitochondria with branches. Application of this method to differentiation into other lineages will explain the energy levels required to control stem cell differentiation. [ABSTRACT FROM AUTHOR]

p-Hydroxybenzyl alcohol (HBA), an active component ofGastrodia elatablume, has been reported to provide neuroprotection by preventing brain damage. Transplantation of mesenchymal stem cell (MSC) has been shown to ameliorate ischemic brain injury in animals. To explore a way that might enhance neuroprotection after brain stroke, we investigated whether the transplantation of neural progenitor cells (NPCs) derived from MSCs from adipose tissue combined with HBA may enhance neuroprotective effects in an animal model of brain stroke. Intracarotid injection of combination therapy groups showed a significant reduction of infarct volume by 2,3,5-triphenyltetrazolium chloride staining and an improvement of neurological functions were observed at 3 days after middle cerebral artery occlusion (MCAO), compared to monotherapy groups. In our studies, immunohistochemistry showed that NPCs are more likely to enter a damaged brain than a contralateral nonischemic brain. Coadministration of HBA and NPCs enhanced the anti-apoptotic effect and reduced the number of terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling-positive apoptotic cells compared to the vehicle and NPCs at 7 days after MCAO. HBA and the combination of HBA +NPCs induced the expression of genes encoding antioxidant proteins, including PDI, Nrf2, endogenous neurotrophic factor gene brain-derived neurotrophic factor, NGF, and VEGF, which enhances angiogenesis in an ischemic brain. These effects might be responsible for the survival of NPCs and improved functional behavior. Our finding indicates that combination therapy of HBA and NPCs enhances neuroprotection against ischemic brain injury. [ABSTRACT FROM AUTHOR]