Abstract
Degenerin proteins, such as the beta epithelial Na+ channel (βENaC), are essential in the intracellular signaling of pressure-induced constriction, an important vascular smooth muscle cell (VSMC) function. While certain cytokines reduce ENaC protein in epithelial tissue, it is unknown if interleukin-17 (IL-17), a potent pro-inflammatory cytokine, directly mediates changes in membrane-associated βENaC in VSMCs. Therefore, we tested the hypothesis that exposure to IL-17 reduces βENaC in VSMCs through canonical mitogen-activated protein kinase (MAPK) signaling pathways. We treated cultured rat VSMCs (A10 cell line) with IL-17 (1–100 ng/mL) for 15 min to 16 h and measured expression of βENaC, p38MAPK, c-jun kinase (JNK), and nuclear factor kappa-light-chain-enhancer of activated B cells (NFκB). IL-17 reduced βENaC protein expression in a concentration-dependent fashion and increased phosphorylation of p38MAPK by 15 min and JNK by 8 h. NFκB was unaffected by IL-17 in VSMCs. IL-17 treatment reduced VSMC viability but had no effect on cell death. To determine the underlying signaling pathway involved in this response, VSMCs were treated before and during IL-17 exposure with p38MAPK or JNK inhibitors. We found that JNK blockade prevented IL-17-mediated βENaC protein suppression. These data demonstrate that the pro-inflammatory cytokine IL-17 regulates VSMC βENaC via canonical MAPK signaling pathways, raising the possibility that βENaC-mediated loss of VSMC function may occur in inflammatory disorders.
Highlights
Vascular smooth muscle cells (VSMCs) are an integral component of vascular blood flow regulation
While numerous molecules contribute to transduction of stretch-induced VSMC contraction, our laboratory has focused on the importance of degenerin proteins in initiation of this response [1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18]
Findings from this study indicate that IL-17 inhibits βENaC expression in a concentration-dependent fashion in VSMC
Summary
Vascular smooth muscle cells (VSMCs) are an integral component of vascular blood flow regulation. Pressure-induced constriction, known as myogenic constriction, is an inherent response of certain small arteries and arterioles, mediated by VSMCs, and a mechanism of local blood flow autoregulation. Degenerin proteins are an evolutionarily conserved family of cation channels, where many members function as sensors [4,6,19,20]. Epithelial Na+ channel (ENaC) proteins are members of this family. The concept that ENaC function is limited to canonical αENaC channels mediating Na+ transport in epithelial tissue is evolving. ENaC proteins are expressed in VSMCs. βENaC is the most abundantly expressed of the three subunits and plays a critical role in mediating pressure-induced changes in vascular tone in small cerebral arteries, renal interlobar arteries, and renal afferent arterioles [5,8,17]
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.