Increased myosin light chain kinase expression in hypertension: Regulation by serum response factor via an insertion mutation in the promoter.
Regulation of gene transcription in vascular smooth muscle cells (VSMCs) by serum response factor (SRF) plays a crucial role in vascular development and in the pathophysiology of vascular diseases. Nevertheless, the regulation of specific genes by SRF in vascular diseases is poorly understood. Therefore, we investigated the regulation of smooth muscle myosin light chain kinase (smMLCK) by using spontaneously hypertensive rats (SHR) as an experimental model. We found that smMLCK expression in blood vessels increases during the development of hypertension and is always greater in blood vessels from SHR compared with normotensive rats. Analysis of the DNA sequences of the promoters isolated from SHR and normotensive rats revealed that SHR contain a 12-base pair insertion adjacent to the CArG box. This insertion increases SRF binding to the CArG box and positively regulates SRF-dependent promoter activity. The increase in smMLCK expression was blocked by dominant-negative SRF, dominant-negative Ras, or antisense oligonucleotides to ERK. In vivo, inhibiting MEK decreased smMLCK expression and blood pressure in SHR partly by decreasing SRF binding to the smMLCK promoter. These data provide novel insight into the regulation of smMLCK expression at the molecular level and demonstrate the importance of SRF in regulating smMLCK promoter activity in SHR.
Han
Yoo-Jeong
YJ
Department of Physiology and Biophysics, College of Medicine, University of Illinois at Chicago, Chicago, IL 60612, USA.
Hu
Wen-Yang
WY
Chernaya
Olga
O
Antic
Nenad
N
Gu
Lianzhi
L
Gupta
Mahesh
M
Piano
Mariann
M
de Lanerolle
Primal
P
D000818:Animals; D001483:Base Sequence; D001794:Blood Pressure / Q000502:physiology; D019556:COS Cells; D002478:Cells, Cultured; D002522:Chlorocebus aethiops; D015971:Gene Expression Regulation, Enzymologic; D006973:Hypertension / Q000201:enzymology* / Q000503:physiopathology; D007438:Introns / Q000235:genetics; D051379:Mice; D020929:Mitogen-Activated Protein Kinase Kinases / Q000037:antagonists & inhibitors; D008969:Molecular Sequence Data; D009131:Muscle, Smooth, Vascular / Q000166:cytology / Q000201:enzymology; D016254:Mutagenesis, Insertional; D018994:Myosin Light Chains / Q000378:metabolism; D009219:Myosin-Light-Chain Kinase / Q000037:antagonists & inhibitors / Q000235:genetics* / Q000378:metabolism*; D010766:Phosphorylation; D011401:Promoter Regions, Genetic / Q000235:genetics*; D011485:Protein Binding; D016283:Proto-Oncogene Proteins p21(ras) / Q000378:metabolism; D051381:Rats; D011918:Rats, Inbred SHR; D026362:Serum Response Factor / Q000378:metabolism*; D015398:Signal Transduction
D018994:Myosin Light Chains; D026362:Serum Response Factor; D009219:Myosin-Light-Chain Kinase; D020929:Mitogen-Activated Protein Kinase Kinases; D016283:Proto-Oncogene Proteins p21(ras)