ASIC2 Synergizes with TRPV1 in the Mechano-Electrical Transduction of Arterial Baroreceptors
Xiaodong Yan1 • Sitao Zhang2 • Haiyan Zhao3 • Ping Liu1 • Haixia Huang1 • Weizhen Niu1 • Wei Wang1,4 • Chen Zhang5
1 Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Capital Medical University, Beijing 100069, China
2 Department of Orthopedics, Xuanwu Hospital, Capital Medical University, Beijing 100053, China
3 Yanjing Medical College, Capital Medical University, Beijing 101300, China
4 Beijing Laboratory for Cardiovascular Precision Medicine, Capital Medical University, Beijing 100069, China
5 Department of Neurobiology, School of Basic Medical Sciences, Beijing Key Laboratory of Neural Regeneration and Repair, Advanced Innovation Center for Human Brain Protection, Capital Medical University, Beijing 100069, China
Abstract
Mechanosensitive ion channels (MSCs) are key molecules in the mechano-electrical transduction of arterial baroreceptors. Among them, acid-sensing ion channel 2 (ASIC2) and transient receptor potential vanilloid subfamily member 1 (TRPV1) have been studied extensively and documented to play important roles. In this study, experiments using aortic arch–aortic nerve preparations isolated from rats revealed that both ASIC2 and TRPV1 are functionally necessary, as blocking either abrogated nearly all pressure-dependent neural discharge. However, whether ASIC2 and TRPV1 work in coordination remained unclear. So we carried out cell-attached patch-clamp recordings in HEK293T cells co-expressing ASIC2 and TRPV1 and found that inhibition of ASIC2 completely blocked stretch-activated currents while inhibition of TRPV1 only partially blocked these currents. Immunofluorescence staining of aortic arch–aortic adventitia from rats showed that ASIC2 and TRPV1 are co-localized in the aortic nerve endings, and co-immunoprecipitation assays confirmed that the two proteins form a compact complex in HEK293T cells and in baroreceptors. Moreover, protein modeling analysis, exogenous co-immunoprecipitation assays, and biotin pull-down assays indicated that ASIC2 and TRPV1 interact directly. In summary, our research suggests that ASIC2 and TRPV1 form a compact complex and function synergistically in the mechano-electrical transduction of arterial baroreceptors. The model of synergism between MSCs may have important biological significance beyond ASIC2 and TRPV1.
Keywords
Acid-sensing ion channel 2; Transient receptor potential vanilloid subfamily member 1; Mechano-electrical transduction; Arterial baroreceptors; Synergism
