Center for Medical Education and Career Development, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan.
Department of Gastroenterology, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan.
PLoS One. 2018 Oct 26;13(10):e0206276. doi: 10.1371/journal.pone.0206276. eCollection 2018.
Adenosine triphosphate (ATP) modulates mechanosensitive vagal afferent nerves in the gastrointestinal tract. ATP is stored in secretory vesicles via the ATP transporter VNUT. Recently, the bisphosphate clodronate was reported to inhibit VNUT and was suggested to be a safe potent therapeutic option for chronic pain. Transient receptor potential vanilloid 4 (TRPV4) is activated by mechanical stimuli and some epoxyeicosatrienoic acids and becomes sensitized under inflammatory conditions. We have previously reported that TRPV4 and VNUT are expressed in mouse esophageal keratinocytes and that TRPV4 activation induces ATP release in gastric epithelial cells. Here we show the expression of TRPV4 and VNUT in normal human gastrointestinal cell derived cell lines (GES-1 and CCD 841) and in tissues from normal and VNUT-KO mice. TRPV4 agonists (GSK101 or 8,9-EET) induced an increase in cytosolic Ca2+ and/or current responses in mouse primary colonic epithelial cells and CCD 841 cells, but not in cells isolated from TRPV4-KO mice. TRPV4 agonists (GSK101 or 5.6-EET) also induced ATP release in GES-1 and CCD 841 cells, which could be blocked by the VNUT inhibitor, clodronate. Thus, VNUT inhibition with clodronate could represent a novel therapeutic option for visceral pain.
三磷酸腺苷（ATP）调节胃肠道中的机械敏感迷走传入神经。ATP 通过 ATP 转运蛋白 VNUT 储存在分泌小泡中。最近，二磷酸氯膦酸盐被报道可抑制 VNUT，并被认为是慢性疼痛的一种安全有效的治疗选择。瞬时受体电位香草酸 4（TRPV4）可被机械刺激和一些环氧化二十碳三烯酸激活，并在炎症条件下变得敏感。我们之前报道过 TRPV4 和 VNUT 在小鼠食管角质形成细胞中表达，并且 TRPV4 激活可诱导胃上皮细胞中 ATP 的释放。在这里，我们展示了 TRPV4 和 VNUT 在正常人类胃肠道细胞衍生细胞系（GES-1 和 CCD 841）和正常和 VNUT-KO 小鼠组织中的表达。TRPV4 激动剂（GSK101 或 8,9-EET）诱导小鼠原代结肠上皮细胞和 CCD 841 细胞中细胞浆 Ca2+增加和/或电流反应，但在 TRPV4-KO 小鼠分离的细胞中则没有。TRPV4 激动剂（GSK101 或 5.6-EET）也可诱导 GES-1 和 CCD 841 细胞中 ATP 的释放，该释放可被 VNUT 抑制剂氯膦酸盐阻断。因此，氯膦酸盐对 VNUT 的抑制可能代表内脏疼痛的一种新的治疗选择。
