PDGF and IL-1beta upregulate cofilin and LIMK2 in canine cultured pulmonary artery smooth muscle cells.
Actin cytoskeleton reorganization is regulated by various actin-binding proteins. Cofilin is the principal filament-depolymerizing protein, whose activity is reduced upon phosphorylation by LIMK. Thus, LIMK and cofilin comprise a signal transduction module regulating actin turnover and myogenic tone in healthy vasculature. Novel functions of smooth muscle cells (SMCs) in the hypertensive pulmonary artery, such as increased motility and proliferation, are supported by the actin cytoskeleton. We therefore hypothesized that bioactive peptides that affect these SMC functions may also result in an upregulation of LIMK and cofilin expression. Semiquantitative RT-PCR and immunoblotting indicated that LIMK2 and cofilin mRNA and protein expression is upregulated in canine pulmonary artery SMCs (PASMCs) exposed to PDGF or IL-1beta (10 ng/ml). Inhibition of ERK MAPKs (U-0126, 10 muM) or p38 MAPK (PD-169316, 10 muM), but not PI3Ks (LY-294002, 50 muM), reduced LIMK2 and cofilin gene expression stimulated by PDGF or IL-1beta. Inhibition of ROCK (Y-27632, 10 muM) reduced only the IL-1beta-stimulated LIMK2 and cofilin expression. These novel observations in PASMCs indicate that LIMK2 and cofilin expression can be induced by PDGF or IL-1beta. This parallel upregulation of LIMK2 and cofilin may have potentially broad functional significance for the progress of pulmonary artery disease.
Bongalon
Shaner
S
Department of Pharmacology, Center of Biomedical Research Excellence, University of Nevada School of Medicine, Reno, NV 89557, USA.
Dai
Yan-Ping
YP
Singer
Cherie A
CA
Yamboliev
Ilia A
IA
D051339:Actin Depolymerizing Factors; D000818:Animals; D002478:Cells, Cultured; D004268:DNA-Binding Proteins / Q000235:genetics*; D004285:Dogs; D005260:Female; D015870:Gene Expression / Q000187:drug effects; D007375:Interleukin-1 / Q000494:pharmacology*; D054461:Lim Kinases; D008297:Male; D008840:Microfilament Proteins / Q000235:genetics*; D009131:Muscle, Smooth, Vascular / Q000166:cytology / Q000187:drug effects* / Q000502:physiology; D010982:Platelet-Derived Growth Factor / Q000494:pharmacology*; D017346:Protein Serine-Threonine Kinases; D011651:Pulmonary Artery / Q000166:cytology*; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology
D051339:Actin Depolymerizing Factors; D004268:DNA-Binding Proteins; D007375:Interleukin-1; D008840:Microfilament Proteins; D010982:Platelet-Derived Growth Factor; C102895:LIMK2 protein, human; D054461:Lim Kinases; D017346:Protein Serine-Threonine Kinases