IPLA2? overexpression in smooth muscle exacerbates angiotensin II-induced hypertension and vascular remodeling.
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ABSTRACT: Calcium independent group VIA phospholipase A(2) (iPLA(2)?) is up-regulated in vascular smooth muscle cells in some diseases, but whether the up-regulated iPLA(2)? affects vascular morphology and blood pressure is unknown. The current study addresses this question by evaluating the basal- and angiotensin II infusion-induced vascular remodeling and hypertension in smooth muscle specific iPLA(2)? transgenic (iPLA(2)?-Tg) mice.Blood pressure was monitored by radiotelemetry and vascular remodeling was assessed by morphologic analysis. We found that the angiotensin II-induced increase in diastolic pressure was significantly higher in iPLA(2)?-Tg than iPLA(2)?-Wt mice, whereas, the basal blood pressure was not significantly different. The media thickness and media?lumen ratio of the mesenteric arteries were significantly increased in angiotensin II-infused iPLA(2)?-Tg mice. Analysis revealed no difference in vascular smooth muscle cell proliferation. In contrast, adenovirus-mediated iPLA(2)? overexpression in cultured vascular smooth muscle cells promoted angiotensin II-induced [(3)H]-leucine incorporation, indicating enhanced hypertrophy. Moreover, angiotensin II infusion-induced c-Jun phosphorylation in vascular smooth muscle cells overexpressing iPLA2? to higher levels, which was abolished by inhibition of 12/15 lipoxygenase. In addition, we found that angiotensin II up-regulated the endogenous iPLA(2)? protein in-vitro and in-vivo.The present study reports that iPLA(2)? up-regulation exacerbates angiotensin II-induced vascular smooth muscle cell hypertrophy, vascular remodeling and hypertension via the 12/15 lipoxygenase and c-Jun pathways.
SUBMITTER: Calderon LE
PROVIDER: S-EPMC3282780 | biostudies-literature | 2012
REPOSITORIES: biostudies-literature
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