title: NF-κB-mediated integrin-linked kinase regulation in angiotensin II-induced pro-fibrotic process in cardiac fibroblasts.
abstract: OBJECTIVE
  Cardiac fibrosis is a final outcome of many clinical conditions that lead to cardiac failure and is characterized by a progressive substitution of cellular elements by extracellular-matrix proteins, such as collagen type I, collagen type II, connective tissue growth factor (CTGF), etc. The aim of this study was to identify the mechanisms responsible for angiotensin II (Ang II)-stimulated cardiac fibrosis using rat neonatal cardiac fibroblasts.
  
  
  METHODS
  Neonatal fibroblasts were transfected with IκBα mutant, constitutively active (ca) integrin-linked kinase (ILK), dominant negative of ILK and small interfering RNA (siRNA) of ILK in the presence and absence of Ang-II stimulation. The pro-fibrotic gene expression and protein levels were determined by quantitative real time PCR and western blotting using their specific probes and antibodies. NF-κB translocation was determined by immunocytochemistry and confocal microscopy images were analyzed.
  
  
  RESULTS
  Our results indicate that overexpression of ILK promotes a pro-fibrotic process by upregulating collagen type I and CTGF genes via activation of nuclear factor-κB (NF-κB) in cardiac fibroblasts. Inactivation of either NF-κB by the super-repressor IκBα or ILK by siRNA significantly attenuates the pro-fibrotic process. Moreover, ILK overexpression triggers NF-κB-p65 translocation to the nucleus, and ILK inhibition prevents the translocation in cardiac fibroblasts stimulated with Ang II.
  
  
  CONCLUSIONS
  Our data suggest that the Ang II-stimulated pro-fibrotic process is regulated by a complex mechanism involving crosstalk between ILK and NF-κB activation. This dual mechanism may play a critical role in the progression of cardiac fibrosis.
authors.affiliation: Division of Molecular Cardiology, Department of Medicine, College of Medicine, Texas A & M Health Science Center; Scott & White; Central Texas Veterans Health Care System, Temple, TX, USA.
authors.forename: Suresh
authors.initials: S
authors.lastname: Thakur
authors.affiliation: Division of Molecular Cardiology, Department of Medicine, College of Medicine, Texas A & M Health Science Center; Scott & White; Central Texas Veterans Health Care System, Temple, TX, USA.
authors.forename: Li
authors.initials: L
authors.lastname: Li
authors.affiliation: Division of Molecular Cardiology, Department of Medicine, College of Medicine, Texas A & M Health Science Center; Scott & White; Central Texas Veterans Health Care System, Temple, TX, USA. Electronic address: sgupta@medicine.tamhsc.edu.
authors.forename: Sudhiranjan
authors.initials: S
authors.lastname: Gupta
mesh_terms: D000804:Angiotensin II / Q000633:toxicity*; D000818:Animals; D000831:Animals, Newborn; D017209:Apoptosis; D015153:Blotting, Western; D049109:Cell Proliferation; D002478:Cells, Cultured; D024042:Collagen Type I / Q000235:genetics / Q000378:metabolism; D055513:Connective Tissue Growth Factor / Q000235:genetics / Q000378:metabolism; D005347:Fibroblasts / Q000187:drug effects / Q000378:metabolism* / Q000473:pathology; D005355:Fibrosis / Q000139:chemically induced / Q000378:metabolism* / Q000473:pathology; D005455:Fluorescent Antibody Technique; D015971:Gene Expression Regulation, Enzymologic; D020672:I-kappa B Proteins / Q000235:genetics / Q000378:metabolism; D050505:Mutant Proteins / Q000235:genetics / Q000378:metabolism; D009206:Myocardium / Q000378:metabolism* / Q000473:pathology; D000072000:NF-KappaB Inhibitor alpha; D016328:NF-kappa B / Q000235:genetics / Q000378:metabolism*; D017346:Protein Serine-Threonine Kinases / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics; D034741:RNA, Small Interfering / Q000235:genetics; D051381:Rats; D060888:Real-Time Polymerase Chain Reaction; D020133:Reverse Transcriptase Polymerase Chain Reaction; D000099200:Scaffold Protein ILK
chemical_list: D000804:Angiotensin II; D024042:Collagen Type I; D055513:Connective Tissue Growth Factor; D020672:I-kappa B Proteins; D050505:Mutant Proteins; D000072000:NF-KappaB Inhibitor alpha; D016328:NF-kappa B; D017346:Protein Serine-Threonine Kinases; D012333:RNA, Messenger; D034741:RNA, Small Interfering; D000099200:Scaffold Protein ILK; C526316:CCN2 protein, rat; C000606206:Nfkbia protein, rat
keywords: ILK; NF-κB; cardiac fibrosis