Does the circadian clock make RPE-mediated ion transport “tick” via <i>SLC12A2</i> (NKCC1)?

The presence of a circadian clock in the retinal pigment epithelium (RPE) was discovered recently. However, little is known about mechanisms or processes regulated by the RPE clock. We cultured ARPE-19 monolayers in a transwell culture system, and we found rhythmic mRNA expression of the sodium-potassium-chloride co-transporter <i>SLC12A2</i>. We localized the corresponding protein product, NKCC1, on the apical membrane of ARPE-19 cells. We found that concentrations of sodium, potassium, and chloride oscillated in apical supernatants. The ion concentration gradients between supernatants strongly correlated with <i>SLC12A2</i> mRNA expression. Our results suggest that the circadian clock regulates ion transport by the RPE via NKCC1 expression.视网膜色素上皮（retinal pigment epithelium, RPE）内存在昼夜节律钟的现象，近年才被探明。然而，目前对于RPE节律钟所调控的分子机制与生物学过程仍知之甚少。我们采用跨室培养系统（transwell culture system）培养ARPE-19细胞单层，观察到钠钾氯协同转运蛋白（sodium-potassium-chloride co-transporter）SLC12A2的mRNA表达呈现节律性变化。我们将该基因对应的蛋白产物NKCC1定位在了ARPE-19细胞的顶膜上。本研究发现，顶室上清液中的钠、钾、氯离子浓度呈现周期性振荡。上清液间的离子浓度梯度与SLC12A2的mRNA表达水平显著相关。本研究结果表明，RPE的昼夜节律钟可通过调控NKCC1的表达，进而调节视网膜色素上皮的离子转运过程。

搜集汇总

背景与挑战

背景概述

该数据集聚焦于视网膜色素上皮（RPE）中昼夜节律钟对离子转运的调控机制，具体研究SLC12A2 (NKCC1)基因的表达节律及其与钠、钾、氯离子浓度振荡的关联。实验使用ARPE-19细胞培养模型，发现NKCC1蛋白定位于顶膜，且离子浓度梯度与mRNA表达相关，表明昼夜节律钟通过NKCC1调控RPE的离子运输。数据集发布于2019年，属于生物物理学、生物化学和医学等领域，包含原始数据文件（如Excel表格），用于支持相关研究分析。