原理:肾纤维化,没有治疗方法,是各种慢性肾脏病(CKD)的共同病理特征。肾小管细胞损伤在肾脏纤维化中起关键作用。通常,受损的肾小管细胞表现出明显的脂质积累。然而,潜在的机制仍然知之甚少。方法:采用质谱法测定CKD患者和CKD模型标本中的2-花生酰甘油(2-AG)水平。将装载2-AG的纳米颗粒输注到单侧输尿管梗阻(UUO)小鼠中。检测脂质积累和肾纤维化。此外,单酰基甘油脂肪酶(MAGL),水解酶2-AG,在CKD患者和模型中进行评估。产生管状细胞特异性MAGL敲入小鼠。此外,MAGL重组蛋白也被给予单侧缺血再灌注损伤(UIRI)小鼠。此外,包括RNA测序在内的一系列方法,代谢组学,原代细胞培养,脂质染色,等。被使用。结果:CKD患者和模型的血清或肾脏中2-AG升高。补充2-AG进一步通过大麻素受体2型(CB2)/β-连环蛋白信号传导诱导脂质积累和纤维形成。β-连环蛋白敲除阻断2-AG/CB2诱导的脂肪酸β-氧化(FAO)缺乏和脂质积累。值得注意的是,CKD中MAGL显著降低,与脂质积累和纤维化对齐。MAGL在管状细胞中的特异性转基因显着保存了FAO,抑制肾小管细胞中的脂质介导的毒性,最终阻碍了纤维的形成.此外,在UIRI小鼠中补充MAGL也保留了FAO功能,抑制脂质积累,并防止肾脏纤维化。结论:MAGL是肾功能下降的潜在诊断标志物,并通过改善脂毒性作为肾纤维化的新治疗靶点。
Rationale: Renal fibrosis, with no therapeutic approaches, is a common pathological feature in various chronic kidney diseases (CKD). Tubular cell injury plays a pivotal role in renal fibrosis. Commonly, injured tubular cells exhibit significant lipid accumulation. However, the underlying mechanisms remain poorly understood. Methods: 2-arachidonoylglycerol (2-AG) levels in CKD patients and CKD model specimens were measured using mass spectrometry. 2-AG-loaded nanoparticles were infused into unilateral ureteral obstruction (UUO) mice. Lipid accumulation and renal fibrosis were tested. Furthermore, monoacylglycerol lipase (MAGL), the hydrolyzing enzyme of 2-AG, was assessed in CKD patients and models. Tubular cell-specific MAGL knock-in mice were generated. Moreover, MAGL recombination protein was also administered to unilateral ischemia reperfusion injury (UIRI) mice. Besides, a series of methods including RNA sequencing, metabolomics, primary cell culture, lipid staining, etc. were used. Results: 2-AG was increased in the serum or kidneys from CKD patients and models. Supplement of 2-AG further induced lipid accumulation and fibrogenesis through cannabinoid receptor type 2 (CB2)/β-catenin signaling. β-catenin knockout blocked 2-AG/CB2-induced fatty acid β-oxidation (
FAO) deficiency and lipid accumulation. Remarkably, MAGL significantly decreased in CKD, aligning with lipid accumulation and fibrosis. Specific transgene of MAGL in tubular cells significantly preserved
FAO, inhibited lipid-mediated toxicity in tubular cells, and finally retarded fibrogenesis. Additionally, supplementation of MAGL in UIRI mice also preserved
FAO function, inhibited lipid accumulation, and protected against renal fibrosis. Conclusion: MAGL is a potential diagnostic marker for kidney function decline, and also serves as a new therapeutic target for renal fibrosis through ameliorating lipotoxicity.