microRNA (miR) 143/145 is restricted to adult smooth muscle cell (SMC) lineages and mediates, in part, the expression of several SMC contractile genes. Although the function of miR143/145 has begun to be elucidated, its transcriptional regulation in response to various signaling inputs is poorly understood. In an effort to define a miR signature for SMC differentiation, researchers from the University of Rochester School of Medicine and Dentistry screened human coronary artery SMC (HCASM) for miRs modulated by TGF-β1, a known stimulus for SMC differentiation. Array analysis revealed a number of TGF-β1-induced miRs, including miR143/145. Validation studies showed that TGF-β1 stimulated miR-143/145 expression in a dose- and time-dependent manner. The researchers utilized several chemical inhibitors and found that SB203580, a specific inhibitor to p38MAPK, significantly decreased TGF-β1-induced miR-143/145 expression. siRNA studies demonstrated that the effect of TGF-β1 on miR143/145 was dependent upon the myocardin (MYOCD) and serum response factor (SRF) transcriptional switch as well as SMAD4. TGF-β1 stimulated a 580 bp human miR-143/145 enhancer, and mutagenesis studies revealed a critical role for both a known CArG box and an adjacent SMAD binding element (SBE) for full TGF-β1-dependent activation of the enhancer. Chromatin immunoprecipitation assays documented TGF-β1-mediated enrichment of SMAD3 and SMAD4 binding to the enhancer region containing the SBE. pre-miR145 strongly promoted SMC differentiation while an anti-miR145 partially blocked TGF-β1-induced SMC differentiation. These results demonstrate a dual pathway for TGF-β1-induced transcription of miR143/145 thus revealing a novel mechanism underlying TGF-β1-induced human SMC differentiation.

LC SciencesTGF-β1-induced miR143/145 expression in HCASM. A, heat map illustrating relative expression of a sample of miRs in triplicate control or TGF-β1 (1 ng/ml)-treated HCASM. B, qPCR validation of indicated miRs in HCASM treated with 1 ng/ml TGF-β1 for 24 h. (C) and two SMC contractile genes (D) in HCASM following 24-h treatment with varying concentrations of TGF-β1. E, HCASM were treated with TGF-β1 (1 ng/ml) for the indicated times, and qPCR was performed to measure normalized expression of miR143/145, miR21, and miR221.


Related Service

miRNA Microarray Service – LC Sciences provides a microRNA (miRNA) expression profiling service using microarrays based on our in-house developed µParaflo® technology platform. We have standard arrays for all mature miRNAs of all species available in the latest version of the miRBase database (Release 21, July 2014). Our service is comprehensive and includes sample labeling, array hybridization, image data processing and in-depth data analysis. Two-three weeks after receiving your total RNA samples, we’ll send you both the raw and fully analyzed data. [Learn more…]


Reference

Long X, Miano JM. (2011) TGF{beta}1 utilizes distinct pathways for the transcriptional activation of microRNA 143/145 in human coronary artery smooth muscle cells. J Biol Chem [Epub ahead of print]. [article]


Understanding the molecular mechanisms of human heart development and heart disease miR-29a and its targets might be valuable biomarkers for muscle metabolism following growth hormone replacement