Functional cross-talk between angiotensin II and epidermal growth factor receptors in NIH3T3 fibroblasts

J Hypertens. 2002 Apr;20(4):693-9. doi: 10.1097/00004872-200204000-00027.

Abstract

Background: The main angiotensin (Ang) II subtype receptors (AT1R and AT2R) are involved in cellular growth processes and exert functionally antagonistic effects.

Objective: To characterize the mechanisms by which Ang II receptors influence growth, by investigating the interactions between Ang II subtype receptors and epidermal growth factor (EGF) receptors on mitogen-activated protein kinase (MAPK) pathway activation.

Design and methods: The experiments were performed using a mouse fibroblast cell line, NIH3T3, by transient co-transfection with rat AT1R or AT2R expression vectors, or both. Extracellular-signal-regulated kinase (ERK)1/2 phosphorylation was analysed by western blot and the ERK activity was evaluated using PathDetect, an in-vivo signal transduction pathway trans-reporting system. Selective Ang II receptor antagonists (losartan for AT1R and PD123319 for AT2R) were used to investigate the contributions of each receptor to the response observed.

Results: Our data show that, in this cellular model, both Ang II receptors phosphorylate ERK1/2. However, in the cells expressing AT1R, the EGF-induced MAPK pathway was enhanced in the presence of Ang II in a synergistic fashion. In contrast, a reduction of EGF-induced MAPK activation was observed in the cells expressing AT2R. In cells expressing both Ang II subtype receptors, Ang II promoted an enhancement of EGF-induced MAPK activation. However, in the presence of the AT1R antagonist, losartan, the effect of EGF was reduced.

Conclusion: These data indicate the existence of an opposite cross-talk of AT1R and AT2R with EGF receptors, and suggest a complex functional interaction between these pathways in the regulation of cellular growth processes.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • 3T3 Cells
  • Animals
  • Cell Division / physiology
  • Enzyme Activation
  • ErbB Receptors / metabolism*
  • Mice
  • Mitogen-Activated Protein Kinases / metabolism
  • RNA, Messenger / genetics
  • RNA, Messenger / metabolism
  • Receptor Cross-Talk
  • Receptor, Angiotensin, Type 1
  • Receptor, Angiotensin, Type 2
  • Receptors, Angiotensin / genetics
  • Receptors, Angiotensin / metabolism*
  • Transfection

Substances

  • RNA, Messenger
  • Receptor, Angiotensin, Type 1
  • Receptor, Angiotensin, Type 2
  • Receptors, Angiotensin
  • ErbB Receptors
  • Mitogen-Activated Protein Kinases