School of Life Sciences, University of Warwick, Coventry, United Kingdom.
PLoS One. 2013 Aug 29;8(8):e71819. doi: 10.1371/journal.pone.0071819. eCollection 2013.
Ketamine, a mild hallucinogenic class C drug, is the fastest growing 'party drug' used by 16-24 year olds in the UK. As the recreational use of Ketamine increases we are beginning to see the signs of major renal and bladder complications. To date however, we know nothing of a role for Ketamine in modulating both structure and function of the human renal proximal tubule. In the current study we have used an established model cell line for human epithelial cells of the proximal tubule (HK2) to demonstrate that Ketamine evokes early changes in expression of proteins central to the adherens junction complex. Furthermore we use AFM single-cell force spectroscopy to assess if these changes functionally uncouple cells of the proximal tubule ahead of any overt loss in epithelial cell function. Our data suggests that Ketamine (24-48 hrs) produces gross changes in cell morphology and cytoskeletal architecture towards a fibrotic phenotype. These physical changes matched the concentration-dependent (0.1-1 mg/mL) cytotoxic effect of Ketamine and reflect a loss in expression of the key adherens junction proteins epithelial (E)- and neural (N)-cadherin and β-catenin. Down-regulation of protein expression does not involve the pro-fibrotic cytokine TGFβ, nor is it regulated by the usual increase in expression of Slug or Snail, the transcriptional regulators for E-cadherin. However, the loss in E-cadherin can be partially rescued pharmacologically by blocking p38 MAPK using SB203580. These data provide compelling evidence that Ketamine alters epithelial cell-to-cell adhesion and cell-coupling in the proximal kidney via a non-classical pro-fibrotic mechanism and the data provides the first indication that this illicit substance can have major implications on renal function. Understanding Ketamine-induced renal pathology may identify targets for future therapeutic intervention.
氯胺酮，一种轻度致幻类 C 级药物，是英国 16-24 岁人群中使用增长最快的“派对药物”。随着氯胺酮的消遣性使用增加，我们开始看到其导致主要肾脏和膀胱并发症的迹象。然而，迄今为止，我们对于氯胺酮在调节人类肾近端小管的结构和功能方面一无所知。在目前的研究中，我们使用了一种已建立的人近端肾小管上皮细胞模型细胞系（HK2），证明氯胺酮会引起与黏着连接复合物核心蛋白表达的早期变化。此外，我们使用原子力显微镜单细胞力谱来评估这些变化是否会导致近端肾小管细胞在明显丧失上皮细胞功能之前出现功能解偶联。我们的数据表明，氯胺酮（24-48 小时）会导致细胞形态和细胞骨架结构发生巨大变化，向纤维表型发展。这些物理变化与氯胺酮的浓度依赖性（0.1-1mg/mL）细胞毒性作用相匹配，反映了关键黏着连接蛋白上皮（E）-和神经（N）-钙粘蛋白和β-连环蛋白表达的丧失。蛋白表达的下调不涉及促纤维化细胞因子 TGFβ，也不受 Slug 或 Snail（E-钙粘蛋白的转录调节剂）通常表达增加的调节。然而，使用 SB203580 阻断 p38 MAPK 可以部分挽救 E-钙粘蛋白的表达缺失。这些数据提供了令人信服的证据，表明氯胺酮通过非经典的促纤维化机制改变了肾脏近端的上皮细胞间黏附和细胞连接，并且数据首次表明这种非法物质可能对肾功能产生重大影响。了解氯胺酮诱导的肾脏病理学可能为未来的治疗干预确定目标。
