Angiotensin II induces renal plasminogen activator inhibitor-1 and cyclooxygenase-2 expression post-transcriptionally via activation of the mRNA-stabilizing factor human-antigen R

Am J Pathol. 2009 Apr;174(4):1252-63. doi: 10.2353/ajpath.2009.080652. Epub 2009 Feb 26.

Abstract

Angiotensin (Ang) II-induced fibrosis of the kidney is characterized by the enhanced expression of profibrotic and proinflammatory genes, including the serine protease inhibitor plasminogen activator inhibitor-1 (PAI-1) and cyclooxygenase-2 (COX-2). In addition to transcriptional regulation, both genes are subject to post-transcriptional control by AU-rich destabilizing elements that reside within the 3' untranslated region of the mRNA. We demonstrated that the continuous infusion of AngII in rats induced fibrosis concomitant with a significant increase in glomerular PAI-1 and COX-2 expression levels. Using RNA pull-down assays and electromobility shift assays, we demonstrated the increased binding of the ubiquitous RNA-binding protein human-antigen R (HuR) to the mRNAs of both PAI-1 and COX-2 in the cytoplasmic fractions of renal homogenates from AngII-treated rats. Actinomycin D experiments in rat mesangial cells revealed that AngII stabilizes both mRNAs via HuR as proven by small interfering RNA. Mechanistically, AngII promotes an increase in nucleo-cytoplasmic HuR shuttling, which was blocked by the PKC inhibitor rottlerin and the type-I AngII (AT(1)) receptor antagonist valsartan but was unaffected by both AT(2) receptor antagonists PD123319 and CGP42112. Co-immunoprecipitation revealed that AngII treatment caused an increase in nuclear PKC-delta concomitant with binding to nuclear HuR both in vitro and in vivo. The post-transcriptional regulation of PAI-1 and COX-2 by PKC-delta-dependent HuR shuttling may contribute to the pathogenesis of hypertensive nephrosclerosis triggered by AngII.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Angiotensin II / metabolism*
  • Angiotensin II / pharmacology
  • Animals
  • Antigens, Surface / metabolism
  • Cyclooxygenase 2 / metabolism*
  • ELAV Proteins
  • ELAV-Like Protein 1
  • Electrophoretic Mobility Shift Assay
  • Fibrosis
  • Fluorescent Antibody Technique
  • Gene Expression Regulation
  • Humans
  • Hypertension / complications
  • Immunohistochemistry
  • Immunoprecipitation
  • Kidney Diseases / etiology
  • Kidney Diseases / metabolism*
  • Male
  • Plasminogen Activator Inhibitor 1 / metabolism*
  • Protein Processing, Post-Translational / physiology*
  • RNA, Messenger
  • RNA-Binding Proteins / metabolism
  • Rats
  • Rats, Sprague-Dawley
  • Reverse Transcriptase Polymerase Chain Reaction

Substances

  • Antigens, Surface
  • ELAV Proteins
  • ELAV-Like Protein 1
  • ELAVL1 protein, human
  • Plasminogen Activator Inhibitor 1
  • RNA, Messenger
  • RNA-Binding Proteins
  • Angiotensin II
  • Cyclooxygenase 2