Integrative genomics identifies DSCR1 (RCAN1) as a novel NFAT-dependent mediator of phenotypic modulation in vascular smooth muscle cells.
Vascular smooth muscle cells (SMCs) display remarkable phenotypic plasticity in response to environmental cues. The nuclear factor of activated T-cells (NFAT) family of transcription factors plays a critical role in vascular pathology. However, known functional NFAT gene targets in vascular SMCs are currently limited. Publicly available whole-genome expression array data sets were analyzed to identify differentially expressed genes in human, mouse and rat SMCs. Comparison between vehicle and phenotypic modulatory stimuli identified 63 species-conserved, upregulated genes. Integration of the 63 upregulated genes with an in silico NFAT-ome (a species-conserved list of gene promoters containing at least one NFAT binding site) identified 18 putative NFAT-dependent genes. Further intersection of these 18 potential NFAT target genes with a mouse in vivo vascular injury microarray identified four putative NFAT-dependent, injury-responsive genes. In vitro validations substantiated the NFAT-dependent role of Cyclooxygenase 2 (COX2/PTGS2) in SMC phenotypic modulation and uncovered Down Syndrome Candidate Region 1 (DSCR1/RCAN1) as a novel NFAT target gene in SMCs. We show that induction of DSCR1 inhibits calcineurin/NFAT signaling through a negative feedback mechanism; DSCR1 overexpression attenuates NFAT transcriptional activity and COX2 protein expression, whereas knockdown of endogenous DSCR1 enhances NFAT transcriptional activity. Our integrative genomics approach illustrates how the combination of publicly available gene expression arrays, computational databases and empirical research methods can answer specific questions in any cell type for a transcriptional network of interest. Herein, we report DSCR1 as a novel NFAT-dependent, injury-inducible, early gene that may serve to negatively regulate SMC phenotypic switching.
Lee
Monica Y
MY
Cardiovascular Division, Department of Medicine, University of Virginia, 409 Lane Road, Charlottesville, VA 22908, USA.
Garvey
Sean M
SM
Baras
Alex S
AS
Lemmon
Julia A
JA
Gomez
Maria F
MF
Schoppee Bortz
Pamela D
PD
Daum
Guenter
G
LeBoeuf
Renee C
RC
Wamhoff
Brian R
BR
D000818:Animals; D002135:Calcium-Binding Proteins; D002478:Cells, Cultured; D051546:Cyclooxygenase 2 / Q000235:genetics / Q000378:metabolism; D004268:DNA-Binding Proteins; D005260:Female; D023281:Genomics; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins / Q000235:genetics / Q000378:metabolism*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D009124:Muscle Proteins / Q000235:genetics / Q000378:metabolism*; D032389:Myocytes, Smooth Muscle / Q000378:metabolism*; D050778:NFATC Transcription Factors / Q000235:genetics / Q000378:metabolism*; D011485:Protein Binding; D051381:Rats
D002135:Calcium-Binding Proteins; D004268:DNA-Binding Proteins; C511512:DSCR1 protein, mouse; D047908:Intracellular Signaling Peptides and Proteins; D009124:Muscle Proteins; D050778:NFATC Transcription Factors; C108612:RCAN1 protein, human; C548050:RCAN1 protein, rat; D051546:Cyclooxygenase 2