Mechanical stretch induces endothelial nitric oxide synthase gene expression in neonatal rat cardiomyocytes.
1. Mechanical stretch leads to cardiac hypertrophy and may ultimately cause heart failure. However, the effect of mechanical stretch on gene induction in cardiomyocytes remains to be determined. 2. In the present study, we compared transcript profiles of mechanically stretched neonatal rat cardiomyocytes with those of unstretched cells using cDNA microarrays. The microarrays contained probes for 480 known genes, including those involved in signal transduction, cell cycle regulation, the cytoskeleton and cell motility. Eighteen genes, including the eNOS gene, were identified as having significantly differential expression in response to mechanical stretch in cardiomyocytes. 3. Northern and western blot analysis further quantified the expression of the eNOS gene. Mechanical stretch increased constitutive NOS activity and nitric oxide (NO) production. The NO donor s-nitroso-N-acetylpenicillamine (SNAP) inhibited mechanical stretch-stimulated protein synthesis, as measured by [3H]-leucine uptake. In addition, cardiomyocytes were infected with adenoviral vectors encoding cDNA for eNOS (Ad-eNOS) and a phosphoglycerate kinase (PGK) empty vector (Ad-PGK). In contrast with Ad-PGK-infected cells, in cardiomyocytes infected with Ad-eNOS, there was increased calcium-dependent NOS activity and nitrite production. Cardiomyocytes infected with Ad-eNOS exhibited diminished mechanical stretch-stimulated protein synthesis. In contrast, in eNOS-knockdown cells, the increased eNOS protein levels and NOS activity induced by mechanical stretch were abolished, but protein synthesis was enhanced. 4. The results of the present study indicate that eNOS gene expression is induced by mechanical stretch, leading to increased constitutive NOS activity and NO production, which may be a negative regulator in cardiomyocyte hypertrophy.
Cheng
Tzu-Hurng
TH
Department of Biological Science and Technology, China Medical University, Taichung, Taiwan.
Chen
Jeremy J-W
JJ
Shih
Neng-Lang
NL
Lin
Jia-Wei
JW
Liu
Ju-Chi
JC
Chen
Yen-Ling
YL
Chen
Cheng-Hsien
CH
Chen
Jin-Jer
JJ
D000818:Animals; D000831:Animals, Newborn; D002478:Cells, Cultured; D020869:Gene Expression Profiling; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects; D055785:Gene Knockdown Techniques; D006984:Hypertrophy / Q000235:genetics; D009129:Muscle Tonus / Q000187:drug effects / Q000235:genetics; D032383:Myocytes, Cardiac / Q000378:metabolism* / Q000473:pathology / Q000502:physiology; D009569:Nitric Oxide / Q000378:metabolism; D020030:Nitric Oxide Donors / Q000494:pharmacology; D052250:Nitric Oxide Synthase Type III / Q000235:genetics*; D020411:Oligonucleotide Array Sequence Analysis; D014176:Protein Biosynthesis / Q000187:drug effects / Q000235:genetics; D034741:RNA, Small Interfering / Q000494:pharmacology; D051381:Rats; D013314:Stress, Mechanical; D014162:Transfection
D020030:Nitric Oxide Donors; D034741:RNA, Small Interfering; D009569:Nitric Oxide; D052250:Nitric Oxide Synthase Type III