补脾益肾颗粒调控肾小管PGC-1α介导脂代谢延缓慢性肾脏病进展的作用和机制

Renal tubule injury is closely associated with the progression of chronic kidney disease (CKD). Recent studies have shown that lipid metabolism imbalance mediated by the core regulator PGC-1α lead to the down-regulation of fatty acid oxidation (FAO) in renal tubular epithelial cells (TECs), resulting in renal tubule damage and renal fibrosis, and inhibition of such down-regulation could provide renal protective effects. Our previous clinical trial found that Bupi Yishen Formula can effectively delay the progress of kidney function in CKD patients with spleen-kidney qi deficiency syndrome. In addition Bupi Yishen Formula can attenuate lipid accumulation and the down-regulation of PGC-1α in TGFβ-induced HK-2. However, it is not clear whether Bupi Yishen Formula could improve the prognosis of CKD by regulating the tubular PGC-1α-mediated lipid metabolism pathway. We speculate that Bupi Yishen Formula may increase FAO and ATP products, reduce lipid accumulation, and thus, alleviate renal tubule injury and CKD progression by inhibiting the down-regulation of PGC-1α in TECs. This project, from the perspective of the tubule epithelial lipid metabolism, intends to explore the role of Bupi Yishen Formula in regulating tubular PGC-1α-mediated lipid metabolism pathway and its mechanism for attenuating CKD progression with our skilled techniques of 5/6 nephrectomy rat model and renal tubule separation from animal and cell level. This study is expected to reveal the modern scientific connotation of Bupi Yishen treatment and provide experimental evidence for its clinical application in CKD therapy.

肾小管损伤与慢性肾脏病（CKD）进展密切相关。新近研究表明能量代谢核心调节因子PGC-1α介导的脂代谢失衡可引起肾小管上皮细胞脂肪酸氧化（FAO）下调，导致肾小管损害及肾脏纤维化，对其进行干预起到肾脏保护作用。我们前期研究发现补脾益肾颗粒可有效延缓CKD脾肾气虚证肾功能进展；缓解TGFβ诱导HK-2细胞脂质蓄积及PGC-1α表达下调。然而，补脾益肾颗粒是否通过调控肾小管PGC-1α介导脂代谢通路改善CKD预后尚不清楚。我们推测：补脾益肾颗粒可能通过抑制肾小管PGC-1α下调，促进FAO和ATP生成，减少脂质蓄积，缓解肾小管损伤及CKD进展。本项目拟从肾小管细胞脂代谢调控的角度，利用课题组熟练构建5/6肾切除大鼠模型和分离肾小管等技术，从动物和细胞水平探讨补脾益肾颗粒对肾小管PGC-1α介导脂代谢的调控作用及其延缓CKD的机制，为CKD补脾益肾法现代科学内涵的揭示及其临床应用提供实验依据。

慢性肾脏疾病（CKD）是一种新兴的全球性流行病，其与较高的医疗成本和死亡率密切相关。最近的研究表明，肾小管上皮细胞(TECs)脂肪酸代谢功能障碍可诱导肾小管纤维化、细胞凋亡和炎症反应，而肾小管FAO的恢复则有利于肾纤维化和CKD进展。在最近的一项随机对照试验中，中药复方补脾益肾方(BYF)在保护晚期CKD患者肾功能及预防复合严重不良结局方面表现出优于氯沙坦的效果。我们先前的研究表明，BYF抑制TLR4/NF-κB和PI3K/AKT通路可能是通过干预CKD动物模型肾纤维化的重要机制，但其机制尚未完全阐明。在本研究中，我们采用基于转录组的非偏倚的探索性方法对腺嘌呤诱导的CKD大鼠的纤维化肾组织样本进行了全面分析以产生假设，然后用腺嘌呤诱导和5/6次全肾切除术诱导的肾纤维化模型检验假设，并通过对人类细胞和CKD患者芯片数据库以及人类肾活检样本的研究以建立人类相关性和临床意义。这些研究结果表明，BYF有效地改善了腺嘌呤诱导的CKD大鼠纤维化模型的肾脏组织学损伤，并预防了肾功能障碍。BYF给药能够显著减弱肾纤维化中促纤维化和凋亡标志物的显著增加。来自腺嘌呤大鼠的纤维化肾脏的转录组分析发现，脂肪酸代谢是受BYF治疗影响的关键的异常调节通路。BYF显著逆转腺嘌呤诱导的和5/6肾切除术诱导的纤维化肾脏和TGFβ1诱导的肾小管HK2细胞的FAO缺陷和细胞内脂质堆积。BYF治疗对脂肪酸代谢的这些保护作用与受损肾功能的显著改善和促纤维化表型的改变正相关。此外，我们发现表现有小管间质纤维化的多种发病机制的人类CKD中，FAO关键酶和脂肪酸氧化调节因子表达下调。综上所述，我们的探索性研究发现，BYF可能通过调节肾小管上皮细胞的脂肪酸代谢对肾纤维化起保护作用，这可能是其对肾纤维化和CKD进展起保护作用的关键机制。