Petukhova Elena O, Maltsev Dmitry I, Pechinko Daria Y, Kalinichenko Andrei L, Belousov Vsevolod V, Podgorny Oleg V
Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow 117997, Russia.
Pirogov Russian National Research Medical University, Moscow 117997, Russia.
ACS Chem Biol. 2025 Jul 17. doi: 10.1021/acschembio.5c00306.
Transient receptor potential vanilloid subfamily member 1 (TRPV1), also known as the capsaicin receptor, plays a central role in detecting noxious heat, regulating thermal homeostasis, and mediating inflammatory responses. TRPV1 is a cell membrane-associated, nonselective cation channel. TRPV1 activation triggers transmembrane depolarizing currents and elevates the level of cytosolic calcium. A large fraction of TRPV1 is known to reside in the endoplasmic reticulum (ER), and ligand-dependent activation of this fraction elicits calcium release from the ER. However, whether ER-located TRPV1 participates in the heat-evoked cytosolic calcium elevation remains unresolved. In this study, we heterologously expressed human TRPV1 in HEK293TN cells, which do not normally exhibit physiological responses to temperature variations, and recorded calcium changes in response to heat stimulation and capsaicin treatment in the presence of extracellular calcium and after its removal. Our experiments revealed that heat-evoked calcium responses were abolished in hTRPV1-expressing HEK293TN cells upon removal of extracellular calcium, whereas the TRPV1 agonist capsaicin still elicited an elevation of intracellular calcium. The restoration of extracellular calcium after its withdrawal recovered heat-evoked calcium responses. Our findings argue for differential sensitivity of TRPV1 pools (ER vs plasma membrane) for discriminating various physiological and noxious signals and may allow for elucidating the structural basis of temperature-dependent gating.
瞬时受体电位香草酸亚家族成员1（TRPV1），也被称为辣椒素受体，在检测有害热、调节热稳态以及介导炎症反应中发挥核心作用。TRPV1是一种与细胞膜相关的非选择性阳离子通道。TRPV1的激活会触发跨膜去极化电流并提高胞质钙水平。已知很大一部分TRPV1存在于内质网（ER）中，该部分的配体依赖性激活会引发内质网释放钙。然而，内质网定位的TRPV1是否参与热诱发的胞质钙升高仍未得到解决。在本研究中，我们在通常对温度变化不表现出生理反应的HEK293TN细胞中异源表达人TRPV1，并在存在细胞外钙和去除细胞外钙后记录对热刺激和辣椒素处理的钙变化。我们的实验表明，在去除细胞外钙后，表达hTRPV1的HEK293TN细胞中热诱发的钙反应被消除，而TRPV1激动剂辣椒素仍能引起细胞内钙升高。去除细胞外钙后再恢复细胞外钙可恢复热诱发的钙反应。我们的研究结果表明TRPV1池（内质网与质膜）对区分各种生理和有害信号具有不同的敏感性，并可能有助于阐明温度依赖性门控的结构基础。
