title: Serum response factor-dependent MicroRNAs regulate gastrointestinal smooth muscle cell phenotypes.
abstract: OBJECTIVE
  Smooth muscle cells (SMCs) change phenotypes under various pathophysiological conditions. These changes are largely controlled by the serum response factor (SRF), a transcription factor that binds to CC (A/T)6 GG (CArG) boxes in SM contractile genes. MicroRNAs (miRNA) regulate transitions among SMC phenotypes. The SMC miRNA transcriptome (SMC miRNAome) and its regulation by SRF have not been determined.
  
  
  METHODS
  We performed massively parallel sequencing to identify gastrointestinal (GI) SMC miRNA transcriptomes in mice and humans. SMC miRNA transcriptomes were mapped to identify all CArG boxes, which were confirmed by SRF knockdown and microarrays. Quantitative polymerase chain reaction was used to identify SMC-phenotypic miRNAs in differentiated and proliferating SMCs. Bioinformatics and target validation analysis showed regulation of SMC phenotype by SRF-dependent, SMC-phenotype miRNAs.
  
  
  RESULTS
  We cloned and identified GI miRNA transcriptomes using genome-wide analyses of mouse and human cells. The SM miRNAome consisted of hundreds of unique miRNAs that were highly conserved among both species. We mapped miRNAs CArG boxes and found that many had an SRF-dependent signature in the SM miRNAome. The SM miRNAs CArG boxes had several distinct features. We also identified approximately 100 SMC-phenotypic miRNAs that were induced in differentiated or proliferative SMC phenotypes. We showed that SRF-dependent, SMC-phenotypic miRNAs bind and regulate Srf and its cofactors, myocadin (Myocd) and member of ETS oncogene family Elk1.
  
  
  CONCLUSIONS
  The GI SMC phenotypes are controlled by SRF-dependent, SMC-phenotypic miRNAs that regulate expression of SRF, MYOCD, and ELK1.
authors.affiliation: Department of Physiology and Cell Biology, University of Nevada School of Medicine, Reno, Nevada, USA.
authors.forename: Chanjae
authors.initials: C
authors.lastname: Park
authors.forename: Grant W
authors.initials: GW
authors.lastname: Hennig
authors.forename: Kenton M
authors.initials: KM
authors.lastname: Sanders
authors.forename: Jonathan H
authors.initials: JH
authors.lastname: Cho
authors.forename: William J
authors.initials: WJ
authors.lastname: Hatton
authors.forename: Doug
authors.initials: D
authors.lastname: Redelman
authors.forename: Jong Kun
authors.initials: JK
authors.lastname: Park
authors.forename: Sean M
authors.initials: SM
authors.lastname: Ward
authors.forename: Joseph M
authors.initials: JM
authors.lastname: Miano
authors.forename: Wei
authors.initials: W
authors.lastname: Yan
authors.forename: Seungil
authors.initials: S
authors.lastname: Ro
mesh_terms: D000818:Animals; D001665:Binding Sites; D002454:Cell Differentiation; D049109:Cell Proliferation; D002478:Cells, Cultured; D019295:Computational Biology; D004742:Enhancer Elements, Genetic; D041981:Gastrointestinal Tract / Q000378:metabolism*; D020869:Gene Expression Profiling / Q000379:methods; D005786:Gene Expression Regulation; D005838:Genotype; D049452:Green Fluorescent Proteins / Q000235:genetics; D006801:Humans; D019426:Integrases / Q000235:genetics; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D035683:MicroRNAs / Q000378:metabolism*; D032389:Myocytes, Smooth Muscle / Q000378:metabolism*; D018995:Myosin Heavy Chains / Q000235:genetics; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism; D020411:Oligonucleotide Array Sequence Analysis; D010641:Phenotype; D016133:Polymerase Chain Reaction; D011401:Promoter Regions, Genetic; D034622:RNA Interference; D026362:Serum Response Factor / Q000235:genetics / Q000378:metabolism*; D015534:Trans-Activators / Q000235:genetics / Q000378:metabolism; D050807:ets-Domain Protein Elk-1 / Q000235:genetics / Q000378:metabolism; D000099251:Myocardin
chemical_list: D049452:Green Fluorescent Proteins; D019426:Integrases; D035683:MicroRNAs; D018995:Myosin Heavy Chains; D009687:Nuclear Proteins; D026362:Serum Response Factor; D015534:Trans-Activators; D050807:ets-Domain Protein Elk-1; D000099251:Myocardin; C485184:enhanced green fluorescent protein; C045073:Cre recombinase