Nikolaev Maxim V, Dorofeeva Natalia A, Komarova Margarita S, Korolkova Yuliya V, Andreev Yaroslav A, Mosharova Irina V, Grishin Eugene V, Tikhonov Denis B, Kozlov Sergey A
I.M.Sechenov Institute of Evolutionary Physiology and Biochemistry RAS, St.Petersburg, Russia.
Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, RAS, Moscow, Russia.
PLoS One. 2017 May 5;12(5):e0177077. doi: 10.1371/journal.pone.0177077. eCollection 2017.
TRPV1 (vanilloid) receptors are activated by different types of stimuli including capsaicin, acidification and heat. Various ligands demonstrate stimulus-dependent action on TRPV1. In the present work we studied the action of polypeptides isolated from sea anemone Heteractis crispa (APHC1, APHC2 and APHC3) on rat TRPV1 receptors stably expressed in CHO cells using electrophysiological recordings, fluorescent Ca2+ measurements and molecular modeling. The APHCs potentiated TRPV1 responses to low (3-300 nM) concentrations of capsaicin but inhibited responses to high (>3.0 μM) concentrations. The activity-dependent action was also found for TRPV1 responses to 2APB and acidification. Thus the action mode of APHCs is bimodal and depended on the activation stimuli strength-potentiation of low-amplitude responses and no effect/inhibition of high-amplitude responses. The double-gate model of TRPV1 activation suggests that APHC-polypeptides may stabilize an intermediate state during the receptor activation. Molecular modeling revealed putative binding site at the outer loops of TRPV1. Binding to this site can directly affect activation by protons and can be allosterically coupled with capsaicin site. The results are important for further investigations of both TRPV1 and its ligands for potential therapeutic use.
瞬时感受器电位香草酸亚型1（TRPV1）受体可被多种不同类型的刺激激活，包括辣椒素、酸化和热刺激。各种配体对TRPV1表现出依赖于刺激的作用。在本研究中，我们利用电生理记录、荧光钙测量和分子模拟，研究了从海葵卷曲异海葵中分离出的多肽（APHC1、APHC2和APHC3）对稳定表达于CHO细胞中的大鼠TRPV1受体的作用。APHCs增强了TRPV1对低浓度（3 - 300 nM）辣椒素的反应，但抑制了对高浓度（>3.0 μM）辣椒素的反应。对于TRPV1对2-氨基乙氧基二苯硼酸（2APB）和酸化的反应，也发现了这种依赖于活性的作用。因此，APHCs的作用模式是双峰的，并且取决于激活刺激的强度——增强低幅度反应，对高幅度反应无影响/抑制。TRPV1激活的双门控模型表明，APHC多肽可能在受体激活过程中稳定中间状态。分子模拟揭示了TRPV1外环上的假定结合位点。与该位点结合可直接影响质子介导的激活，并可与辣椒素位点发生变构偶联。这些结果对于进一步研究TRPV1及其配体的潜在治疗用途具有重要意义。
