Angiogenic and Restorative Abilities of Human Mesenchymal Stem Cells Were Reduced Following Treatment With Serum From Diabetes Mellitus Type 2 Patients

This experiment investigated the impact of serum from patients with type 2 diabetes mellitus on the angiogenic behavior of human mesenchymal stem cells in vitro. Changes in the level of Ang‐1, Ang‐2, cell migration, and trans‐differentiation into pericytes and endothelial lineage were monitored after 7 days. The interaction of mesenchymal stem cells with endothelial cells were evaluated using surface plasmon resonance technique. Paracrine restorative effect of diabetic stem cells was tested on pancreatic β cells. Compared to data from FBS and normal serum, diabetic serum reduced the stem cell survival and chemotaxis toward VEGF and SDF‐1α (P < 0.05). Diabetic condition were found to decline cell migration rate and the activity of MMP‐2 and ‐9 (P < 0.05). The down‐regulation of VEGFR‐2 and CXCR‐4 was observed with an increase in the level of miR‐1‐3p and miR‐15b‐5p at the same time. The paracrine angiogenic potential of diabetic stem cells was disturbed via the changes in the dynamic of Ang‐1, Ang‐2, and VEGF. Surface plasmon resonance analysis showed that diabetes could induce an aberrant increase in the interaction of stem cells with endothelial cells. After treatment with diabetic serum, the expression of VE‐cadherin and NG2 and ability for uptake of Dil‐Ac‐LDL were reduced (P < 0.01). Conditioned media prepared from diabetic stem cells were unable to decrease fatty acid accumulation in β‐cells (P < 0.05). The level of insulin secreted by β‐cells was not affected after exposure to supernatant from diabetic or non‐diabetic mesenchymal stem cells. Data suggest diabetes could decrease angiogenic and restorative effect of stem cells in vitro. J. Cell. Biochem. 119: 524–535, 2018. © 2017 Wiley Periodicals, Inc.     

BMP2 induces osteoblast apoptosis in a maturation state and noggin-dependent manner

Large doses of bone morphogenetic protein 2 (BMP2) are used clinically to induce bone formation in challenging bone defects. However, complications after treatment include swelling, ectopic bone formation, and adjacent bone resorption. While BMP2 can be effective, it is important to characterize the mechanism of the deleterious effects to optimize its use. The aim of this study was to determine the effect of BMP2 on apoptosis in osteoblast lineage cells and to determine the role of the BMP inhibitor Noggin in this process. Human mesenchymal stem cells (MSCs), immature osteoblast‐like MG63 cells, and mature normal human osteoblasts (NHOst) were treated with BMP2. A model system of increased endogenous BMP signaling was created by silencing Noggin (shNOG‐MG63). Finally, the BMP pathway regulating apoptosis in NHOst was examined using BMP signaling inhibitors (5Z‐7‐oxozeaenol, dorsomorphin, H‐8). Apoptosis was characterized by caspase‐3, BAX/BCL2, p53, and DNA fragmentation. BMP2 induced apoptosis in a cell‐type dependent manner. While the effect was minor in MSCs, MG63 cells had modest increases and NHOst cells had robust increases apoptosis after BMP2 treatment. Apoptosis was significantly higher in shNOG‐MG63 than MG63 cells. 5Z‐7‐oxozeaenol and dorsomorphin eliminated the BMP2‐induced increase in DNA fragmentation in NHOst, suggesting roles for TAB/TAK1 and Smad signaling. These results indicate that the apoptotic effect of BMP2 is dependent on cell maturation state, inducing apoptosis in committed osteoblasts through Smad and TAB/TAK1 signaling, and is regulated by Noggin. Dose and delivery must be optimized in therapeutic applications of BMP2 to minimize complications. J. Cell. Biochem. 113: 3236–3245, 2012. © 2012 Wiley Periodicals, Inc.     

The Role of Epigenetic Regulation and Pluripotency‐Related MicroRNAs in Differentiation of Pancreatic Stem Cells to Beta Cells

In this study, we aimed to research the effects of class‐I HDACs and glucose on differentiation of pancreatic islet derived mesenchymal stem cells (PI‐MSCs) to beta cells. Beta cell differentiation determined by flow cytometric analysis and gene expression levels of PDX1, PAX4, PAX6, NKX6.1, NGN3, INS2, and GLUT2. As a result the valproic acid, is an inhibitor of class‐I HDACs, caused the highest beta cell differentiation in PI‐MSCs. However, the cells in this group were at early stages of differentiation. Glucose co‐administration to this group carried the differentiation to higher levels, but these newly formed beta cells were not functional. Moreover, reduction in the levels of pluripotency factors that Oct3/4, c‐Myc, and Nanog were parallel to beta cell differentiation. Also, the levels of HDAC1 and acetylated H3/H4 were increased and methylated H3 was decreased by VPA treatment. In addition, we have detected over expression in genes of miR‐18a‐5p, miR‐19b‐5p, miR‐30d‐3p, miR‐124, miR‐146a‐5p, miR‐184, miR‐335, and miR‐433‐5p in parallel to beta cell differentiation. As the conclusion, this study is important for understanding the epigenetic mechanism that controls the beta cell differentation and it suggests new molecules that can be used for diagnosis, and treatment of diabetes. J. Cell. Biochem. 119: 455–467, 2018. © 2017 Wiley Periodicals, Inc.     

DNA甲基化与基因表达调控研究进展

表观遗传修饰是指不改变DNA序列的、可遗传的对碱基和组蛋白的化学修饰,主要包括DNA甲基化、组蛋白修饰、染色质重塑以及非编码RNA等.表观遗传修饰是更高层次的基因表达调控手段.DNA甲基化是一种重要的表观遗传修饰,参与基因表达调控、基因印记、转座子沉默、X染色体失活以及癌症发生等重要生物学过程.近年来随着研究方法和技术的进步,全基因组DNA甲基化的研究广泛兴起,多个物种全基因组甲基化图谱被破译,全局水平对DNA甲基化的研究不仅利于在宏观层面上了解DNA甲基化的特性与规律,同时也为深入分析DNA甲基化的生物学功能与调控奠定了基础.结合最新研究进展综述DNA甲基化在基因组中的分布模式、规律以及和基因转录的关系等.     

Human adipose CD34+CD90+ stem cells and collagen scaffold constructs grafted in vivo fabricate loose connective and adipose tissues

Stem cell based therapies for the repair and regeneration of various tissues are of great interest for a high number of diseases. Adult stem cells, instead, are more available, abundant and harvested with minimally invasive procedures. In particular, mesenchymal stem cells (MSCs) are multi‐potent progenitors, able to differentiate into bone, cartilage, and adipose tissues. Human adult adipose tissue seems to be the most abundant source of MSCs and, due to its easy accessibility; it is able to give a considerable amount of stem cells. In this study, we selected MSCs co‐expressing CD34 and CD90 from adipose tissue. This stem cell population displayed higher proliferative capacity than CD34^?CD90^? cells and was able to differentiate in vitro into adipocytes (PPARγ⁺ and adiponectin⁺) and endothelial cells (CD31⁺VEGF⁺Flk1⁺). In addition, in methylcellulose without VEGF, it formed a vascular network. The aim of this study was to investigate differentiation potential of human adipose CD34⁺/CD90⁺ stem cells loaded onto commercial collagen sponges already used in clinical practice (Gingistat) both in vitro and in vivo. The results of this study clearly demonstrate that human adult adipose and loose connective tissues can be obtained in vivo, highlighting that CD34⁺/CD90 ASCs are extremely useful for regenerative medicine. J. Cell. Biochem. 114: 1039–1049, 2013. © 2012 Wiley Periodicals, Inc.