Anti-TGFBR3 monoclonal antibody, clone 42409

MicroRNAs play important roles during cell reprogramming and differentiation. In this study, we identified the miR-497 approximate to 195 cluster, a member of the miR-15 family, as strongly upregulated with age of postnatal bone development in vivo and late differentiation stages of primary osteoblasts cultured in vitro. Early expression of miR-195-5p inhibits differentiation and mineralization. Microarray analyses along with quantitative PCR demonstrate that miR-195-5p alters the gene regulatory network of osteoblast differentiation and impairs the induction of bone morphogenetic protein (BMP) responsive genes. Applying reporter gene and Western blot assays, we show that miR-195-5p interferes with the BMP/Smad-pathway in a dose-dependent manner. Systematically comparing the changes in mRNA levels in response to miR-195-5p overexpression with the changes observed in the natural course of osteoblast differentiation, we demonstrate that microRNAs of the miR-15 family affect several target genes involved in BMP signaling. Predicted targets including Furin, a protease that cleaves pro-forms, genes encoding receptors such as Acvr2a, Bmp1a, Dies1, and Tgfbr3, molecules within the cascade like Smad5, transcriptional regulators like Ski and Zfp423 as well as Mapk3 and Smurf1 were validated by quantitative PCR. Taken together, our data strongly suggest that miR-497 approximate to 195 cluster microRNAs act as intracellular antagonists of BMP signaling in bone cells. (c) 2014 American Society for Bone and Mineral Research.

TGF-beta type III receptor (T beta RIII) is a coreceptor for TGF beta family members required for high-affinity binding of these ligands to their receptors, potentiating their cellular functions. TGF-beta [1-3], bone morphogenetic proteins (BMP2/4) and inhibins regulate different checkpoints during T cell differentiation. Although T beta RIII is expressed on hematopoietic cells, the role of this receptor in the immune system remains elusive. Here, we provide the first evidence that T beta RIII is developmentally expressed during T cell ontogeny, and plays a crucial role in thymocyte differentiation. Blocking of endogenous T beta RIII in fetal thymic organ cultures led to a delay in DN-DP transition. In addition, in vitro development of T beta RIII-/- thymic lobes also showed a significant reduction in absolute thymocyte numbers, which correlated with increased thymocyte apoptosis, resembling the phenotype reported in Inhibin alpha(-/-) thymic lobes. These data suggest that Inhibins and T beta RIII may function as a molecular pair regulating T cell development.