Dysbiosis of intestinal microbiota mediates tubulointerstitial injury in diabetic nephropathy via the disruption of cholesterol homeostasis
Dysbiosis of intestinal microbiota mediates tubulointerstitial injury in diabetic nephropathy via the disruption of cholesterol homeostasis
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DOI：
10.7150/thno.40571
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发表时间：
2020-01-01
期刊：
影响因子：
12.4
通讯作者：
Ma, Kun Ling
中科院分区：
文献类型：
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作者：
Hu, Ze Bo;Lu, Jian;Ma, Kun Ling
背景：我们先前的研究表明，在糖尿病肾病(DN)中，胆固醇稳态的破坏促进了肾小管间质损伤。本研究旨在进一步探讨肠道微生物区系失调对这一过程的影响，并探讨其可能的机制。方法：用健康供体组的糖尿病大鼠口服广谱抗生素或粪便微生物区系移植(FMT)，以及醋酸钠刺激的人肾2(HK-2)细胞，观察肠道微生物区系对胆固醇稳态的影响。粪便16S rDNA测序测定肠道微生物区系分布。用气相色谱分析法检测血清醋酸盐水平。用免疫组织化学染色、免疫荧光染色和免疫印迹法检测G蛋白偶联受体43(GPR43)和参与胆固醇稳态的分子的蛋白表达。结果：肠道微生物区系的耗竭可显著减轻蛋白尿和肾小管间质损伤。有趣的是，服用抗生素的糖尿病大鼠的血清醋酸盐水平也显著降低，并与肾脏中的胆固醇含量呈正相关。一项体外研究表明，醋酸盐显著增加了HK-2细胞中胆固醇的积累，这是由于主要调节胆固醇合成和摄取的蛋白质表达增加所致。正如预期的那样，FMT通过推翻胆固醇稳态的破坏，有效地降低了糖尿病大鼠的血清醋酸盐水平，并减轻了糖尿病大鼠的肾小管间质损伤。此外，GPR43 siRNA处理通过减少控制胆固醇合成和摄取的蛋白的表达，阻断了醋酸盐介导的HK-2细胞胆固醇平衡失调。结论：我们的研究首次证明肠道微生物区系产生的醋酸盐通过激活GPR43介导了胆固醇平衡失调，从而促进了糖尿病肾病的肾小管间质损伤，提示肠道微生物区系重编程可能成为糖尿病肾病防治的新策略。
Background: Our previous study demonstrated that the disruption of cholesterol homeostasis promotes tubulointerstitial injury in diabetic nephropathy (DN). This study aimed to further investigate the effects of gut microbiota dysbiosis on this process and explored its potential mechanism.Methods: Diabetic rats treated with broad-spectrum oral antibiotics or faecal microbiota transplantation (FMT) from the healthy donor group and human kidney 2 (HK-2) cells stimulated with sodium acetate were used to observe the effects of gut microbiota on cholesterol homeostasis. The gut microbiota distribution was measured by 16S rDNA sequencing with faeces. Serum acetate level was examined by gas chromatographic analysis. Protein expression of G protein coupled receptor 43 (GPR43) and molecules involved in cholesterol homeostasis were assessed by immunohistochemical staining, immunofluorescence staining, and Western Blotting.Results: Depletion of gut microbiota significantly attenuated albuminuria and tubulointerstitial injury. Interestingly, serum acetate levels were also markedly decreased in antibiotics-treated diabetic rats and positively correlated with the cholesterol contents in kidneys. An in vitro study demonstrated that acetate significantly increased cholesterol accumulation in HK-2 cells, which was caused by increased expression of proteins mainly modulating cholesterol synthesis and uptake. As expected, FMT effectively decreased serum acetate levels and alleviated tubulointerstitial injury in diabetic rats through overriding the disruption of cholesterol homeostasis. Furthermore, GPR43 siRNA treatment blocked acetate-mediated cholesterol homeostasis dysregulation in HK-2 cells through decreasing the expression of proteins governed cholesterol synthesis and uptake.Conclusion: Our studies for the first time demonstrated that the acetate produced from gut microbiota mediated the dysregulation of cholesterol homeostasis through the activation of GPR43, thereby contributing to the tubulointerstitial injury of DN, suggesting that gut microbiota reprogramming might be a new strategy for DN prevention and therapy.