Translocation of PKGla acts on TRPV4-C1 heteromeric channels to inhibit endothelial Ca2＋ entry  

作　　者：Peng ZHANG Ai-qin MAO Chun-yuan SUN Xiao-dong ZHANG Qiong-xi PAN Dan-tong YANG Jian JIN Chun-lei TANG Zhen-yu YANG Xiao-qiang YAO Xiao-jie LU Xin MA 

机构地区：[1]School of Pharmaceutical Sciences, Jiangnan University, Wuxi 214122, China [2]Wuxi People's Hospital Heart Centre, Jiangnan University, Wuxi 214122, China [3]School of Biomedical Sciences, the Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China [4]Wuxi Neuroscience Center of Jiangnan University & Department of Neurosurgery, Wuxi Second Hospital Affiliated Nanjiang Medical University & Wuxi Second People's Hospital of Jiangsu Province, Wuxi 214002, China

出　　处：《Acta Pharmacologica Sinica》2016年第9期1199-1207,共9页中国药理学报（英文版）

摘　　要：Aim： TRPV4-C1 heteromeric channels contribute to store-operated Ca2＋ entry in vascular endothelial cells. However, the negative regulation of these channels is not fully understood. This study was conducted to investigate the inhibitory effect of PKGla on TRPV4-C1 heteromeric channels. Methods： Immuno-fluorescence resonance energy transfer （FRET） was used to explore the spatial proximity of PKGla and TRPCl. Phosphorylation of endogenous TRPCl was tested by phosphorylation assay. [Ca2＋]i transients and cation current in MAECs were assessed with Fura-2 fluorescence and whole-cell recording, respectively. In addition, rat mesenteric arteries segments were prepared and vascular relaxation was examined with wire myography. Results： In immuno-FRET experiments, after exposure of these cells to 8-Br-cGMP, more PKG1α was observed in the plasma membrane, and PKG1α and TRPC1 were observed to be in closer proximity. TAT-TRPC1S172 and TAT-TRPC1T313 peptide fragments, which contain the PKG targeted residues Ser172 and Thr313, respectively, were introduced into isolated endothelial cells to abrogate the translocation of PKGla. Furthermore, a phosphorylation assay demonstrated that PKG directly phosphorylates TRPC1 at Ser172 and Thr313 in endothelial cells. In addition, PKG activator 8-Br-cGMP markedly reduced the magnitude of the 4aPDD-induced and 11,12-EET-induced [Ca2＋]i transients, the cation current and vascular relaxation. Conclusion： This study uncovers a novel mechanism by which PKG negatively regulates endothelial heteromeric TRPV4-C1 channels through increasing the spatial proximity of TRPV4-C1 to PKG1α via translocation and through phosphorylating Ser172 and Thr313 of TRPCI.Aim： TRPV4-C1 heteromeric channels contribute to store-operated Ca2＋ entry in vascular endothelial cells. However, the negative regulation of these channels is not fully understood. This study was conducted to investigate the inhibitory effect of PKGla on TRPV4-C1 heteromeric channels. Methods： Immuno-fluorescence resonance energy transfer （FRET） was used to explore the spatial proximity of PKGla and TRPCl. Phosphorylation of endogenous TRPCl was tested by phosphorylation assay. [Ca2＋]i transients and cation current in MAECs were assessed with Fura-2 fluorescence and whole-cell recording, respectively. In addition, rat mesenteric arteries segments were prepared and vascular relaxation was examined with wire myography. Results： In immuno-FRET experiments, after exposure of these cells to 8-Br-cGMP, more PKG1α was observed in the plasma membrane, and PKG1α and TRPC1 were observed to be in closer proximity. TAT-TRPC1S172 and TAT-TRPC1T313 peptide fragments, which contain the PKG targeted residues Ser172 and Thr313, respectively, were introduced into isolated endothelial cells to abrogate the translocation of PKGla. Furthermore, a phosphorylation assay demonstrated that PKG directly phosphorylates TRPC1 at Ser172 and Thr313 in endothelial cells. In addition, PKG activator 8-Br-cGMP markedly reduced the magnitude of the 4aPDD-induced and 11,12-EET-induced [Ca2＋]i transients, the cation current and vascular relaxation. Conclusion： This study uncovers a novel mechanism by which PKG negatively regulates endothelial heteromeric TRPV4-C1 channels through increasing the spatial proximity of TRPV4-C1 to PKG1α via translocation and through phosphorylating Ser172 and Thr313 of TRPCI.

关 键 词：vascular endothelial cells store-operated Ca2＋ entry TRPV4-Cl heteromeric channels PKG 8-Br-cGMP 4aPDD 11 12-EET vascular relaxation 

分 类 号：R[医药卫生]