Serum response factor-dependent MicroRNAs regulate gastrointestinal smooth muscle cell phenotypes

Gastroenterology. 2011 Jul;141(1):164-75. doi: 10.1053/j.gastro.2011.03.058. Epub 2011 Apr 5.


Background & aims: 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.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Animals
  • Binding Sites
  • Cell Differentiation
  • Cell Proliferation
  • Cells, Cultured
  • Computational Biology
  • Enhancer Elements, Genetic
  • Gastrointestinal Tract / metabolism*
  • Gene Expression Profiling / methods
  • Gene Expression Regulation
  • Genotype
  • Green Fluorescent Proteins / genetics
  • Humans
  • Integrases / genetics
  • Mice
  • Mice, Inbred C57BL
  • Mice, Transgenic
  • MicroRNAs / metabolism*
  • Myocytes, Smooth Muscle / metabolism*
  • Myosin Heavy Chains / genetics
  • Nuclear Proteins / genetics
  • Nuclear Proteins / metabolism
  • Oligonucleotide Array Sequence Analysis
  • Phenotype
  • Polymerase Chain Reaction
  • Promoter Regions, Genetic
  • RNA Interference
  • Serum Response Factor / genetics
  • Serum Response Factor / metabolism*
  • Trans-Activators / genetics
  • Trans-Activators / metabolism
  • ets-Domain Protein Elk-1 / genetics
  • ets-Domain Protein Elk-1 / metabolism


  • MicroRNAs
  • Nuclear Proteins
  • Serum Response Factor
  • Trans-Activators
  • enhanced green fluorescent protein
  • ets-Domain Protein Elk-1
  • myocardin
  • Green Fluorescent Proteins
  • Cre recombinase
  • Integrases
  • Myosin Heavy Chains