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Cell Signal. 2014 Dec;26(12):3027-35. doi: 10.1016/j.cellsig.2014.09.010. Epub 2014 Sep 19.

Angiotensin-(1-7) abolishes AGE-induced cellular hypertrophy and myofibroblast transformation via inhibition of ERK1/2.

Author information

1
The Hypertension & Vascular Disease Center, Wake Forest University Health Sciences, Winston-Salem, NC, USA.
2
The Hypertension & Vascular Disease Center, Wake Forest University Health Sciences, Winston-Salem, NC, USA. Electronic address: mchappel@wfubmc.edu.

Abstract

Angiotensin-(1-7) (Ang-(1-7))/AT7-Mas receptor axis is an alternative pathway within the renin-angiotensin system (RAS) that generally opposes the actions of Ang II/AT1 receptor pathway. Advanced glycated end product (AGEs) including glucose- and methylglyoxal-modified albumin (MGA) may contribute to the development and progression of diabetic nephropathy in part through activation of the Ang II/AT1 receptor system; however, the influence of AGE on the Ang-(1-7) arm of the RAS within the kidney is unclear. The present study assessed the impact of AGE on the Ang-(1-7) axis in NRK-52E renal epithelial cells. MGA exposure for 48 h significantly reduced the intracellular levels of Ang-(1-7) approximately 50%; however, Ang I or Ang II expression was not altered. The reduced cellular content of Ang-(1-7) was associated with increased metabolism of the peptide to the inactive metabolite Ang-(1-4) [MGA: 175±9 vs.

CONTROL:

115±11 fmol/min/mg protein, p<0.05, n=3] but no change in the processing of Ang I to Ang-(1-7). Treatment with Ang-(1-7) reversed MGA-induced cellular hypertrophy and myofibroblast transition evidenced by reduced immunostaining and protein expression of α-smooth muscle actin (α-SMA) [0.4±0.1 vs. 1.0±0.1, respectively, n=3, p<0.05]. Ang-(1-7) abolished AGE-induced activation of the MAP kinase ERK1/2 to a similar extent as the TGF-β receptor kinase inhibitor SB58059; however, Ang-(1-7) did not attenuate the MGA-stimulated release of TGF-β. The AT7-Mas receptor antagonist D-Ala(7)-Ang-(1-7) abolished the inhibitory actions of Ang-(1-7). In contrast, AT1 receptor antagonist losartan did not attenuate the MGA-induced effects. We conclude that Ang-(1-7) may provide an additional therapeutic approach to the conventional RAS blockade regimen to attenuate AGE-dependent renal injury.

KEYWORDS:

Advanced glycation endproducts; Angiotensin; EMT; ERK1/2; TGF-B

PMID:
25246357
PMCID:
PMC4254268
DOI:
10.1016/j.cellsig.2014.09.010
[Indexed for MEDLINE]
Free PMC Article
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