UCIBIO, REQUIMTE, Laboratory of Toxicology, Department of Biological Sciences, Faculty of Pharmacy, University of Porto, Porto 4050-313, Portugal.
Toxicol Sci. 2019 Jun 1;169(2):422-435. doi: 10.1093/toxsci/kfz050.
The widespread recreational use of synthetic cannabinoids (SCBs) represents a major public health issue, as reports of intoxications and deaths following SCB use rapidly mount up. Specifically, a direct link between SCB use and acute kidney injury (AKI) has been established, although the pathophysiologic mechanisms remain undefined. Here we assessed the in vitro nephrotoxicity of 3 commonly detected and structurally distinct SCBs-AB-FUBINACA, JWH-122, and THJ-2201-in human proximal tubule cells (HK-2), to ascertain potential similarities and/or differences regarding their nephrotoxicity signatures. We showed that 2 of the 3 SCBs tested, namely JWH-122 and THJ-2201, at in vivo relevant concentrations (1 nM-1 μM), triggered apoptotic cell death pathways, mainly through a shared mechanism involving the deregulation of mitochondrial function (ie, with mitochondrial membrane hyperpolarization and increased intracellular ATP levels), as the primary molecular signature of nephrotoxicity mechanism. Noteworthy, no SCB affected cell viability (MTT reduction, lactate dehydrogenase release, Neutral Red inclusion). Use of the cannabinoid receptor (CBR) antagonists SR141716A and SR144528, as well as HEK293T cells, which do not express CBRs, confirmed the involvement of these receptors in SCB-mediated mitochondrial membrane hyperpolarization but not on other events, suggesting an off-target action regulating SCB-induced kidney cell death. Our results further strengthen the relevance of the endocannabinoid system in maintaining mitochondrial function in kidney cells, as we demonstrate that HK-2 incubation with CBR antagonists or inhibitors of endocannabinoid biosynthesis (ie, methyl arachydonyl fluorophosphonate, tetrahydrolipstatin) alone produced deleterious effects similar to those now reported for SCBs. Overall, SCB-induced nephrotoxicity seems to be mainly regulated at the mitochondrial level, but the specific mechanisms involved require further clarification.
合成大麻素（SCB）的广泛娱乐性使用是一个主要的公共卫生问题，因为 SCB 使用导致中毒和死亡的报告迅速增加。具体来说，已经确定了 SCB 使用与急性肾损伤（AKI）之间的直接联系，尽管病理生理机制仍未确定。在这里，我们评估了 3 种常见检测到的结构不同的 SCB-AB-FUBINACA、JWH-122 和 THJ-2201 在人近端肾小管细胞（HK-2）中的体外肾毒性，以确定它们在肾毒性特征方面的潜在相似性和/或差异。我们表明，在所测试的 3 种 SCB 中的 2 种，即 JWH-122 和 THJ-2201，在体内相关浓度（1 nM-1 μM）下，触发了凋亡细胞死亡途径，主要通过一种共同的机制，涉及线粒体功能的失调（即，线粒体膜超极化和细胞内 ATP 水平增加），作为肾毒性机制的主要分子特征。值得注意的是，没有 SCB 影响细胞活力（MTT 减少、乳酸脱氢酶释放、中性红包含）。使用大麻素受体（CBR）拮抗剂 SR141716A 和 SR144528 以及不表达 CBR 的 HEK293T 细胞证实了这些受体在 SCB 介导的线粒体膜超极化中的参与，但不参与其他事件，表明其在调节 SCB 诱导的肾脏细胞死亡方面存在脱靶作用。我们的结果进一步加强了内源性大麻素系统在维持肾脏细胞中线粒体功能方面的相关性，因为我们证明 HK-2 与 CBR 拮抗剂或内源性大麻素生物合成抑制剂（即甲基花生四烯酸氟磷酸盐、四氢脂酶抑制剂）孵育会产生类似于现在报道的 SCB 的有害影响。总体而言，SCB 诱导的肾毒性似乎主要在线粒体水平上受到调节，但具体机制仍需进一步阐明。
