TRPC1/TRPC3 channels mediate lysophosphatidylcholine-induced apoptosis in cultured human coronary artery smooth muscles cells.

Yuan Wang,Yan Wang,Gui-Rong Li

doi:10.18632/oncotarget.10853

Yuan Wang, Yan Wang + Show 1 more

Open Access

https://doi.org/10.18632/oncotarget.10853

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Journal: Oncotarget	Publication Date: Jul 26, 2016
Citations: 26	License type: cc-by

Affiliation: Xiamen University, University of Hong Kong

Abstract

The earlier study showed that lysophosphatidylcholine (lysoPC) induced apoptosis in human coronary artery smooth muscle cells (SMCs); however, the related molecular mechanisms are not fully understood. The present study investigated how lysoPC induces apoptosis in cultured human coronary artery SMCs using cell viability assay, flow cytometry, confocal microscopy, and molecular biological approaches. We found that lysoPC reduced cell viability in human coronary artery SMCs by eliciting a remarkable Ca2+ influx. The effect was antagonized by La3+, SKF-96365, or Pyr3 as well as by silencing TRPC1 or TRPC3. Co-immunoprecipitation revealed that TRPC1 and TRPC3 had protein-protein interaction. Silencing TRPC1 or TRPC3 countered the lysoPC-induced increase of Ca2+ influx and apoptosis, and the pro-apoptotic proteins Bax and cleaved caspase-3 and decrease of the anti-apoptotic protein Bcl-2 and the survival kinase pAkt. These results demonstrate the novel information that TRPC1/TRPC3 channels mediate lysoPC-induced Ca2+ influx and apoptosis via activating the pro-apoptotic proteins Bax and cleaved caspase-3 and inhibiting the anti-apoptotic protein Bcl-2 and the survival kinase pAkt in human coronary artery SMCs, which implies that TRPC1/TRC3 channels may be the therapeutic target of lysoPC-induced disorders such as atherosclerosis.

Highlights

Oxidized low-density lipoprotein is a well-known culprit of atherogenesis, which causes a series of aberrant initial changes in vascular smooth muscle cells (SMCs) including lipid homeostasis and deposition, dysfunction of Ca2+ homeostasis, and apoptosis [1, 2]
Our results revealed that TRPC1/TRPC3 channels were involved in mediating lysoPC-induced Ca2+ influx and apoptosis by increasing the pro-apoptosis kinases Bax and cleaved caspase-3 and inhibiting the antiapoptosis kinase Bcl-2 and the surviving kinase p-Akt in human coronary artery SMCs
To demonstrate which specific isoforms are involved in lysoPC-induced Ca2+ influx and apoptosis, the gene expression of TRPC channels was initially determined with reversetranscription polymerase chain reaction (RT-PCR), and the channel proteins were verified with Western blots in human coronary artery SMCs (Figure 5A)

Summary

Introduction

Oxidized low-density lipoprotein (ox-LDL) is a well-known culprit of atherogenesis, which causes a series of aberrant initial changes in vascular smooth muscle cells (SMCs) including lipid homeostasis and deposition, dysfunction of Ca2+ homeostasis, and apoptosis [1, 2]. These results indicate that TRPC channels, but not TRPV2 or TRPV4 channels, are involved in lysoPCinduced Ca2+ influx in human coronary artery SMCs. To determine whether blockade of TRPC channels would antagonize the apoptosis induced by lysoPC, cell viability (Figure S1A) was determined with MTT method in cells treated with lysoPC in the presence of TRPC channel blockers SKF96365 and Pyr3 (Figure S1A).

Results

Conclusion