Jiangsu Key Laboratory of Molecular Medicine, Nanjing University School of Medicine, 22 Hankou Road, Nanjing, 210093, China.
J Mol Med (Berl). 2019 Apr;97(4):541-552. doi: 10.1007/s00109-019-01759-z. Epub 2019 Feb 26.
Renal fibrosis is a common histomorphological feature of renal aging and chronic kidney diseases of all etiologies, and its initiation and progression are substantially influenced by aberrant epigenetic modifications of fibrosis-susceptible genes, yet without effective therapy. "Epigenetic diets" exhibit tissue-protective and epigenetic-modulating properties; however, their anti-renal fibrosis functions and the underlying mechanisms are less understood. In this study, we show that genistein, a phytoestrogenic isoflavone enriched in dietary soy products, exhibits impressive anti-renal fibrosis activities by recovering epigenetic loss of Klotho, a kidney-enriched anti-aging and fibrosis-suppressing protein. Mouse fibrotic kidneys induced by UUO (unilateral ureteral occlusion) displayed severer Klotho suppression and adverse expression of renal fibrosis-associated proteins, but genistein administration markedly recovered the Klotho loss and attenuated renal fibrosis and the protein expression abnormalities. The examination of possible causes of the Klotho recovery revealed that genistein simultaneously inhibited histone 3 deacetylation of Klotho promoter and normalized the promoter DNA hypermethylation by suppressing elevated DNA methyltransferase DNMT1 and DNMT3a. More importantly, genistein's anti-renal fibrosis effects on the renal fibrotic lesions and the abnormal expressions of fibrosis-associated proteins were abrogated when Klotho is knockdown by RNA interferences in UUO mice. Thus, our results identify Klotho restoration via epigenetic histone acetylation and DNA demethylation as a critical mechanism of genistein's anti-fibrosis function and shed new lights on the potentials of epigenetic diets in preventing or treating aging or renal fibrosis-associated kidney diseases. KEY MESSAGES: Genistein prevents renal fibrosis and the associated Klotho suppression in UUO mice. Genistein upregulates Klotho in part by reversing the promoter histone 3 hypoacetylation. Genistein also preserves Klotho via relieving Klotho promoter hypermethylation. Genistein demethylates Klotho promoter by inhibiting aberrant DNMT1/3a expression. Genistein restoration of Klotho is essential for its anti-renal fibrosis function.
肾纤维化是肾脏老化和各种病因引起的慢性肾脏病的常见组织学特征，其发生和进展受到纤维化易感基因异常表观遗传修饰的显著影响，但目前尚无有效的治疗方法。“表观遗传饮食”具有组织保护和表观遗传调节特性；然而，它们的抗肾纤维化功能及其潜在机制了解较少。在这项研究中，我们表明，大豆异黄酮金雀异黄素通过恢复肾脏丰富的抗衰老和纤维化抑制蛋白 Klotho 的表观遗传缺失，表现出令人印象深刻的抗肾纤维化活性。UUO（单侧输尿管梗阻）诱导的小鼠纤维化肾脏表现出更严重的 Klotho 抑制和肾脏纤维化相关蛋白的不良表达，但金雀异黄素给药显著恢复了 Klotho 的缺失，并减弱了肾脏纤维化和蛋白表达异常。对 Klotho 恢复的可能原因的检查表明，金雀异黄素通过抑制升高的 DNA 甲基转移酶 DNMT1 和 DNMT3a 来同时抑制 Klotho 启动子的组蛋白 3 去乙酰化并使启动子 DNA 超甲基化正常化。更重要的是，在 UUO 小鼠中通过 RNA 干扰敲低 Klotho 时，金雀异黄素对肾脏纤维化病变和纤维化相关蛋白异常表达的抗肾纤维化作用被阻断。因此，我们的研究结果确定了通过表观遗传组蛋白乙酰化和 DNA 去甲基化恢复 Klotho 作为金雀异黄素抗纤维化功能的关键机制，并为预防或治疗衰老或肾纤维化相关肾脏疾病提供了新的思路。
金雀异黄素可预防 UUO 小鼠的肾纤维化和相关的 Klotho 抑制。金雀异黄素通过逆转启动子组蛋白 3 低乙酰化来部分上调 Klotho。金雀异黄素还通过减轻 Klotho 启动子超甲基化来保护 Klotho。金雀异黄素通过抑制异常的 DNMT1/3a 表达来使 Klotho 启动子去甲基化。金雀异黄素恢复 Klotho 对于其抗肾纤维化功能是必不可少的。
