[IL-1beta stimulates alpha-smooth muscle actin expression through JNK/p38 signal pathway in cultured rat mesangial cells].
To investigate the role of intracellular mitogen activated protein kinase (MAPKs, ERK, JNK and p38) signal pathways in IL-1beta -stimulated alpha-smooth muscle actin (alpha-SMA) expression in rat mesangial cells (rMC), alpha-SMA-promoter gene was transfected into rMC by electro-perforation method and the promoter activity was assayed after IL-1beta (10 ng/ml) stimulation. Protein expression of alpha-SMA was assayed by Western blot. The results were compared between the groups stimulated by IL-1beta with or without PD98059 and SB203580, which are thought to block ERK and p38 pathway, respectively. Dominant-negative-JNKK plasmid was co-transfected in rMC to block JNK pathway. The spatial distribution of alpha-SMA and microfilament-like structure was observed by a confocal laser scanning microscope or an electric microscope. After 6 or 24 h of incubation with IL-1beta, rMC underwent a phenotypic change, which was represented by up-regulation of alpha-SMA promoter activity and protein expression. An increase in alpha-SMA and microfilament-like structure was found around the cell nucleus. Block of JNK and/or p38 pathway greatly inhibited IL-1beta -induced alpha-SMA expression, and the block of p38 pathway also suppressed the basal level of alpha-SMA expression. In contrast, ERK pathway had no influence on the process. It is, therefore, concluded that IL-1beta -stimulated expression of alpha-SMA is due to its protein synthesis and cytoskeleton re-organization in activated rMC. Intracellular signal regulation of alpha-SMA expression seems to be mediated mainly by JNK/p38 pathways, but ERK appears to have no effect on the process.
Wang
Yu
Y
Renal Division, Department of Medicine, Peking University First Hospital, Beijing 100034 Xiao-Mei Li Institute of Nephrology, Peking University, Beijing 100034, China. renalbmu@public.bta.net.cn
Li
Xiao-Mei
XM
Wang
Hai-Yan
HY
D000199:Actins / Q000096:biosynthesis*; D000818:Animals; D002478:Cells, Cultured; D005920:Glomerular Mesangium / Q000378:metabolism*; D007375:Interleukin-1 / Q000494:pharmacology*; D048031:JNK Mitogen-Activated Protein Kinases; D048670:MAP Kinase Kinase 4; D020935:MAP Kinase Signaling System / Q000187:drug effects* / Q000502:physiology; D008297:Male; D020929:Mitogen-Activated Protein Kinase Kinases / Q000187:drug effects* / Q000502:physiology; D020928:Mitogen-Activated Protein Kinases / Q000187:drug effects* / Q000502:physiology; D009130:Muscle, Smooth / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley
D000199:Actins; D007375:Interleukin-1; D048031:JNK Mitogen-Activated Protein Kinases; D020928:Mitogen-Activated Protein Kinases; D048670:MAP Kinase Kinase 4; D020929:Mitogen-Activated Protein Kinase Kinases