L-Carnitine Reduces in Human Conjunctival Epithelial Cells Hypertonic-Induced Shrinkage through Interacting with TRPV1 Channels
L-Carnitine Reduces in Human Conjunctival Epithelial Cells Hypertonic-Induced Shrinkage through Interacting with TRPV1 Channels
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DOI：
10.1159/000363043
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发表时间：
2014-01-01
影响因子：
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通讯作者：
Mergler, Stefan
中科院分区：
文献类型：
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作者：
Khajavi, Noushafarin;Reinach, Peter S.;Mergler, Stefan
背景/目标：眼表面健康取决于结膜上皮（HCjE）层的完整性，因为它可以防止病原体浸润并有助于组织水合维持。由于在干眼病中描述的泪膜高渗性的相同增加可以增加角膜上皮瞬时受体电位香草酸1型（TRPV 1）通道的活性，我们评估了其参与介导L-肉毒碱对这种压力的神经保护作用。研究方法：使用siRNA基因沉默，Ca 2+成像，平面膜片钳和相对细胞体积测量，我们确定这种渗透剂的保护作用是否源于其与TRPV 1的相互作用。结果：TRPV 1激活辣椒素（CAP）和渗透压增加到约450 mOsM都诱导Ca 2+水平的增加。相反，用辣椒平（CPZ）阻断TRPV 1激活完全逆转了这种反应。类似地，L-肉毒碱（1 mM）也降低了潜在的全细胞电流。在钙黄绿素-AM负载的细胞中，高渗诱导的相对细胞体积收缩在暴露于L-肉毒碱期间被完全阻断。另一方面，在TRPV 1基因沉默的细胞中，L-肉毒碱的这种保护作用被消除。结论：通过抑制高渗诱导的TRPV 1活化引起所述的L-肉毒碱保护作用，从而通过所述的Na+依赖性L-肉毒碱转运蛋白增加L-肉毒碱摄取。
Background/Aims: Ocular surface health depends on conjunctival epithelial (HCjE) layer integrity since it protects against pathogenic infiltration and contributes to tissue hydration maintenance. As the same increases in tear film hyperosmolarity described in dry eye disease can increase corneal epithelial transient receptor potential vanilloid type -1 (TRPV1) channel activity, we evaluated its involvement in mediating an osmoprotective effect by L-carnitine against such stress. Methods: Using siRNA gene silencing, Ca2+ imaging, planar patch clamping and relative cell volume measurements, we determined if the protective effects of this osmolyte stem from its interaction with TRPV1. Results: TRPV1 activation by capsaicin (CAP) and an increase in osmolarity to approximate to 450 mOsM both induced increases in Ca2+ levels. In contrast, blocking TRPV1 activation with capsazepine (CPZ) fully reversed this response. Similarly, L-carnitine (1 mM) also reduced underlying whole-cell currents. In calcein-AM loaded cells, hypertonic-induced relative cell volume shrinkage was fully blocked during exposure to L-carnitine. On the other hand, in TRPV1 gene silenced cells, this protective effect by L-carnitine was obviated. Conclusion: The described L-carnitine osmoprotective effect is elicited through suppression of hypertonic-induced TRPV1 activation leading to increases in L-carnitine uptake through a described Na+-dependent L-carnitine transporter Copyright (C) 2014 S Karger AG, Basel