Deregulated MTOR (mechanistic target of rapamycin kinase) is responsible for autophagy defects exacerbating kidney stone development
Deregulated MTOR (mechanistic target of rapamycin kinase) is responsible for autophagy defects exacerbating kidney stone development
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DOI：
10.1080/15548627.2019.1635382
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发表时间：
2020-04
期刊：
影响因子：
13.3
通讯作者：
R. Unno;Tsuyoshi Kawabata;K. Taguchi;Teruaki Sugino;S. Hamamoto;R. Ando;A. Okada;K. Kohri;
中科院分区：
文献类型：
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作者：
R. Unno;Tsuyoshi Kawabata;K. Taguchi;Teruaki Sugino;S. Hamamoto;R. Ando;A. Okada;K. Kohri;
摘要肾结石病是一种在发达国家流行的与生活方式有关的疾病，然而，对这种疾病的有效治疗还没有很好地建立起来。由于肾小管细胞（RTC）中的细胞损伤是导致疾病的原因，因此，我们将重点放在了大自噬/自噬在RTC中的作用上。我们发现，在暴露于草酸钙（CaOx）一水合物晶体的小鼠RTC中以及在具有乙醛酸诱导的CaOx肾钙沉着症的GFP缀合的MAP 1 LC 3B（微管相关蛋白1轻链3 β）转基因小鼠的肾脏中，自噬活性显著降低。这导致受损的细胞内细胞器，如线粒体和溶酶体的积累，其正常功能是由功能性自噬介导的。在具有CaOx肾结石形成者斑块的粘膜中也观察到自噬受损。我们确定自噬的减少是由MTOR（雷帕霉素激酶的机制靶点）的上调引起的，其因此导致上游自噬调节因子TFEB（转录因子EB）的抑制。此外，我们发现MTOR抑制剂可以恢复自噬的减少，减轻晶体-细胞相互作用和与炎症反应增加相关的晶体形成。综上所述，我们得出结论，MTOR失调损害自噬是肾结石形成病理学的一个基本特征，并提出MTOR的化学抑制可能是疾病抑制的一种前瞻性策略。缩略语：会计师事务所：肌动蛋白，β; CaOx：草酸钙;慢性肾脏病：慢性肾脏疾病; COM：一水草酸钙; LGALS 3/半乳糖凝集素-3：凝集素，半乳糖结合，可溶性3; GFP：绿色荧光蛋白; GOX：乙醛酸; HE：苏木精和伊红; MAPLC 3B：微管相关蛋白1轻链3 β; MTOR：雷帕霉素激酶的机制靶点; NAC：N-乙酰-L-半胱氨酸; ROS：活性氧; RTC：肾小管细胞; SQSTM 1/p62：隔离体1; TFEB：转录因子EB; TEM：透射电子显微术; tfLC 3：串联荧光标记的LC 3; 3-MA：3-甲基腺嘌呤。
ABSTRACT Kidney stone disease is a lifestyle-related disease prevalent in developed countries; however, effective medical treatment for the disease is not yet well established. As cellular damage in renal tubular cells (RTCs) is responsible for the disease, here, we focused on the role of macroautophagy/autophagy in RTCs. We found that autophagic activity was significantly decreased in mouse RTCs exposed to calcium oxalate (CaOx) monohydrate crystals and in the kidneys of GFP-conjugated MAP1LC3B (microtubule- associated protein 1 light chain 3 beta) transgenic mice with CaOx nephrocalcinosis induced by glyoxylate. This caused accumulation of damaged intracellular organelles, such as mitochondria and lysosomes, the normal functioning of which is mediated by functional autophagy. An impairment of autophagy was also observed in the mucosa with plaques of CaOx kidney stone formers. We determined that the decrease in autophagy was caused by an upregulation of MTOR (mechanistic target of rapamycin kinase), which consequently resulted in the suppression of the upstream autophagy regulator TFEB (transcription factor EB). Furthermore, we showed that an MTOR inhibitor could recover a decrease in autophagy and alleviate crystal-cell interactions and the formation of crystals associated with increased inflammatory responses. Taken together, we conclude that autophagy compromised by MTOR deregulation is a fundamental feature in the pathology of kidney stone formation, and propose that chemical inhibition of MTOR could be a prospective strategy for disease suppression. Abbreviations: ACTB: actin, beta; CaOx: calcium oxalate; CKD: chronic kidney disease; COM: calcium oxalate monohydrate; LGALS3/galectin-3: lectin, galactose binding, soluble 3; GFP: green fluorescent protein; GOX: glyoxylate; HE: hematoxylin and eosin; MAPLC3B: microtubule- associated protein 1 light chain 3 beta; MTOR: mechanistic target of rapamycin kinase; NAC: N-acetyl-L-cysteine; ROS: reactive oxygen species; RTC: renal tubular cell; SQSTM1/p62: sequestosome 1; TFEB: transcription factor EB; TEM: transmission electron microscopy; tfLC3: tandem fluorescent-tagged LC3; 3-MA: 3-methyladenine.