title: Essential role of cofilin-1 in regulating thrombin-induced RelA/p65 nuclear translocation and intercellular adhesion molecule 1 (ICAM-1) expression in endothelial cells.
abstract: Activation of RhoA/Rho-associated kinase (ROCK) pathway and the associated changes in actin cytoskeleton induced by thrombin are crucial for activation of NF-kappaB and expression of its target gene ICAM-1 in endothelial cells. However, the events acting downstream of RhoA/ROCK to mediate these responses remain unclear. Here, we show a central role of cofilin-1, an actin-binding protein that promotes actin depolymerization, in linking RhoA/ROCK pathway to dynamic alterations in actin cytoskeleton that are necessary for activation of NF-kappaB and thereby expression of ICAM-1 in these cells. Stimulation of human umbilical vein endothelial cells with thrombin resulted in Ser(3) phosphorylation/inactivation of cofilin and formation of actin stress fibers in a ROCK-dependent manner. RNA interference knockdown of cofilin-1 stabilized the actin filaments and inhibited thrombin- and RhoA-induced NF-kappaB activity. Similarly, constitutively inactive mutant of cofilin-1 (Cof1-S3D), known to stabilize the actin cytoskeleton, inhibited NF-kappaB activity by thrombin. Overexpression of wild type cofilin-1 or constitutively active cofilin-1 mutant (Cof1-S3A), known to destabilize the actin cytoskeleton, also impaired thrombin-induced NF-kappaB activity. Additionally, depletion of cofilin-1 was associated with a marked reduction in ICAM-1 expression induced by thrombin. The effect of cofilin-1 depletion on NF-kappaB activity and ICAM-1 expression occurred downstream of IkappaBalpha degradation and was a result of impaired RelA/p65 nuclear translocation and consequently, RelA/p65 binding to DNA. Together, these data show that cofilin-1 occupies a central position in RhoA-actin pathway mediating nuclear translocation of RelA/p65 and expression of ICAM-1 in endothelial cells.
authors.affiliation: Department of Pediatrics (Neonatology), Lung Biology and Disease Program, University of Rochester School of Medicine and Dentistry, Rochester, New York 14642, USA. Fabeha_Fazal@urmc.rochester.edu
authors.forename: Fabeha
authors.initials: F
authors.lastname: Fazal
authors.forename: Kaiser M
authors.initials: KM
authors.lastname: Bijli
authors.forename: Mohd
authors.initials: M
authors.lastname: Minhajuddin
authors.forename: Theo
authors.initials: T
authors.lastname: Rein
authors.forename: Jacob N
authors.initials: JN
authors.lastname: Finkelstein
authors.forename: Arshad
authors.initials: A
authors.lastname: Rahman
mesh_terms: D002467:Cell Nucleus / Q000187:drug effects / Q000378:metabolism*; D051338:Cofilin 1 / Q000378:metabolism*; D042783:Endothelial Cells / Q000166:cytology / Q000187:drug effects* / Q000201:enzymology / Q000378:metabolism*; D055785:Gene Knockdown Techniques; D006801:Humans; D020672:I-kappa B Proteins / Q000378:metabolism; D018799:Intercellular Adhesion Molecule-1 / Q000235:genetics / Q000378:metabolism*; D008954:Models, Biological; D000072000:NF-KappaB Inhibitor alpha; D010766:Phosphorylation / Q000187:drug effects; D011401:Promoter Regions, Genetic / Q000235:genetics; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D011499:Protein Processing, Post-Translational / Q000187:drug effects; D021381:Protein Transport / Q000187:drug effects; D034622:RNA Interference / Q000187:drug effects; D022502:Stress Fibers / Q000187:drug effects / Q000378:metabolism; D013917:Thrombin / Q000494:pharmacology*; D051996:Transcription Factor RelA / Q000378:metabolism*; D054460:rho-Associated Kinases / Q000037:antagonists & inhibitors; D020742:rhoA GTP-Binding Protein / Q000378:metabolism
chemical_list: D051338:Cofilin 1; D020672:I-kappa B Proteins; C000606204:NFKBIA protein, human; D047428:Protein Kinase Inhibitors; D051996:Transcription Factor RelA; D018799:Intercellular Adhesion Molecule-1; D000072000:NF-KappaB Inhibitor alpha; D054460:rho-Associated Kinases; D013917:Thrombin; D020742:rhoA GTP-Binding Protein