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Mechanism of high glucose induced angiotensin II production in rat vascular smooth muscle cells.

Authors: Lavrentyev, EN  Estes, AM  Malik, KU 
Citation: Lavrentyev EN, etal., Circ Res. 2007 Aug 31;101(5):455-64. Epub 2007 Jul 12.
Pubmed: (View Article at PubMed) PMID:17626897
DOI: Full-text: DOI:10.1161/CIRCRESAHA.107.151852

Angiotensin II (Ang II), a circulating hormone that can be synthesized locally in the vasculature, has been implicated in diabetes-associated vascular complications. This study was conducted to determine whether high glucose (HG) (approximately 23.1 mmol/L), a diabetic-like condition, stimulates Ang II generation and the underlying mechanism of its production in rat vascular smooth muscle cells. The contribution of various enzymes involved in Ang II generation was investigated by silencing their expression with small interfering RNA in cells exposed to normal glucose (approximately 4.1 mmol/L) and HG. Angiotensin I (Ang I) was generated from angiotensinogen by cathepsin D in the presence of normal glucose or HG. Although HG did not affect the rate of angiotensinogen conversion, it decreased expression of angiotensin-converting enzyme (ACE), downregulated ACE-dependent Ang II generation, and upregulated rat vascular chymase-dependent Ang II generation. The ACE inhibitor captopril reduced Ang II levels in the media by 90% in the presence of normal glucose and 19% in HG, whereas rat vascular chymase silencing reduced Ang II production in cells exposed to HG but not normal glucose. The glucose transporter inhibitor cytochalasin B, the aldose reductase inhibitor alrestatin, and the advanced glycation end product formation inhibitor aminoguanidine attenuated HG-induced Ang II generation. HG caused a transient increase in extracellular signal-regulated kinase (ERK)1/2 phosphorylation, and ERK1/2 inhibitors reduced Ang II accumulation by HG. These data suggest that polyol pathway metabolites and AGE can stimulate rat vascular chymase activity via ERK1/2 activation and increase Ang II production. In addition, decreased Ang II degradation, which, in part, could be attributable to a decrease in angiotensin-converting enzyme 2 expression observed in HG, contributes to increased accumulation of Ang II in vascular smooth muscle cells by HG.

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CRRD Object Information
CRRD ID: 8142381
Created: 2014-01-31
Species: All species
Last Modified: 2014-01-31
Status: ACTIVE



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RGD is funded by grant HL64541 from the National Heart, Lung, and Blood Institute on behalf of the NIH.