This down-regulation of miR-199a-5p resulted from the up-regulation of PU.1 that was demonstrated to regulate transcription of the miR-199a-2 gene negatively. Overexpression of miR-199a-5p by miR-199a-5p mimic transfection or lentivirus-mediated gene transfer significantly inhibited monocyte/macrophage differentiation of the cell lines or HSPCs. The mRNA encoding an ACVR1B was identified as a direct target of miR-199a-5p. Gradually MLN4924 inhibitor increased ACVR1B expression level was detected during monocyte/macrophage differentiation of the leukemic cell lines and HSPCs, and knockdown of ACVR1B resulted in inhibition of monocyte/macrophage
differentiation of HL-60 and THP-1 cells, which suggested that ACVR1B functions as a positive regulator of monocyte/macrophage differentiation. We demonstrated that miR-199a-5p learn more overexpression or ACVR1B knockdown promoted proliferation of THP-1 cells through increasing phosphorylation of Rb. We also demonstrated that the down-regulation of ACVR1B reduced p-Smad2/3, which resulted in decreased expression of C/EBP, a key regulator of monocyte/macrophage differentiation, and finally, inhibited monocyte/macrophage differentiation.”
“Balasubramaniyan N, Ananthanarayanan M, Suchy FJ. Direct methylation of FXR by Set7/9, a lysine methyltransferase, regulates
the expression of FXR target genes. Am J Physiol Gastrointest Liver Physiol 302: G937-G947, 2012. First published February 16, 2012; doi:10.1152/ajpgi.00441.2011.-The farnesoid X receptor (FXR) is a ligand (bile acid)-dependent nuclear receptor that regulates target genes involved in every aspect of bile acid homeostasis. Upon binding of ligand, FXR recruits an array of coactivators and associated proteins, some of which have intrinsic enzymatic activity that modify histones or even components of the transcriptional complex. In this study, we show chromatin occupancy by the Set7/9 methyltransferase
at the FXR response element (FXRE) and direct methylation of FXR in vivo and in vitro at lysine 206. siRNA depletion of Set7/9 in the Huh-7 liver cell line decreased endogenous mRNAs of the Bucladesine manufacturer FXR target genes, the short heterodimer partner (SHP) and bile salt export pump (BSEP). Mutation of the methylation site at K206 of FXR to an arginine prevented methylation by Set7/9. A pan-methyllysine antibody recognized the wild-type FXR but not the K206R mutant form. An electromobility shift assay showed that methylation by Set7/9 enhanced binding of FXR/retinoic X receptor-alpha to the FXRE. Interaction between hinge domain of FXR (containing K206) and Set7/9 was confirmed by coimmunoprecipitation, GST pull down, and mammalian two-hybrid experiments. Set7/9 overexpression in Huh-7 cells significantly enhanced transactivation of the SHP and BSEP promoters in a ligand-dependent fashion by wild-type FXR but not the K206R mutant FXR. A Set7/9 mutant deficient in methyltransferase activity was also not effective in increasing transactivation of the BSEP promoter.