The cAMP-PKA mechanism involved in the regulation of MEGJ on vascular reactivity after hypoxia
XU Jing
YANG Guang-ming
LI Tao
LIU Liang-ming
Abstract：Objective To observe the the cAMP-PKA mechanism involved in the regulation of myoendothe-lial gap junctions ( MEGJ) on vascular hyporeactivity after hypoxia in rats .Methods The double-sided cells co-culture model of vascular endothelial cells (VECs) and vascular smooth muscle cells(VSMCs) were set up,the pro-tein expression of inducible nitric oxide synthase ( iNOS) and Cx43 was detected via Western blotting ,the VSMCs contraction was detected via the leakage of FITC-BSA, MEGJ formation was observed by immunocytochemistry of phalloidin,and MEGJ communication was reflected by the dye transfer of Sulforhodamine B .Results (1) In the double-sided cells co-culture model,the inhibitor of PKA added to VECs could weaken the increased iNOS expres-sion in VSMCs and VSMCs hyporeactivity after exogenous angiopoietin-2 (Ang2) treatment following hypoxia;(2) The cAMP concentration and PKA activity in VECs increased after hypoxia (P<0.05),further enhanced by exoge-nous Ang2 and weakened by Tie2 siRNA(P<0.05);the antagonists of cAMP or PKA added to VECs could inhibit the increase of Cx43 expression in MEGJ,and weaken the increase of MEGJ formation and communication after exog-enous Ang2 treatment following hypoxia(P<0.05).Conclusion After hypoxia,cAMP-PKA system up-regulates Cx43 protein expression ,MEGJ formation and communication functions ,leading to high expression of iNOS and low reactivity in VSMCs .
Keywords：hypoxiavascular hyporeactivityangiopoietin-2MEGJCx43
Publication Date：2018-01-01
Online Publishing Date：2025-08-15(First online date of this platform, not the publication date of the document)
Pages：4( 39-42 )