Huang Qi, Ouyang Dong-Sheng, Liu Qiong
Department of Clinical Pharmacology, Xiangya Hospital, Central South University, Changsha, China.
Institute of Clinical Pharmacology, Hunan Key Laboratory of Pharmacogenetics, Central South University, Changsha, China.
FEBS Open Bio. 2021 Aug;11(8):2350-2363. doi: 10.1002/2211-5463.13251. Epub 2021 Jul 24.
Diabetic nephropathy (DN) is a common complication in patients with diabetes and a leading cause of mortality. The management of DN in the clinic still remains a challenge. Therefore, the identification of novel compounds for DN treatment and their characterization in preclinical DN models are crucial. Isoeucommin A is a lignan compound isolated from Eucommia ulmoides Oliv, which has not been studied in detail. Our aim was to investigate the effect of Isoeucommin A in DN and to elucidate the molecular mechanisms though which Isoeucommin A acts in vitro and in vivo. We first isolated and purified Isoeucommin A by microporous resin column chromatography and studied the mass spectrogram, as well as the structure of Isoeucommin A, by high-resolution electrospray ionization mass spectroscopy and NMR, respectively. We further established an in vivo rat DN model and measured the changes of blood glucose, body weight, kidney index (KI), blood urea nitrogen, creatinine (CRE), glutathione, malondialdehyde (MDA), SOD, albumin (ALB) and urinary ALB to CRE ratios on treatment with Isoeucommin A. In addition, we measured SOD, MDA, glycogen synthase kinase-3β (GSK-3β), phosphorylated (p)-GSK-3β, nuclear factor erythroid-derived 2-related factor 2 (Nrf2) and heme oxygenase-1 (HO-1) levels by quantitative real-time PCR and western blot, and estimated cell viability by a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide assay. After Isoeucommin A treatment, body weight, as well as SOD, glutathione, HO-1 and Nrf2 expression levels, in DN rats increased in a dose-dependent manner. In contrast, the levels of blood glucose, KI, blood urea nitrogen, CRE, urinary ALB to CRE ratio, tumor necrosis factor-α, interleukin-1β, interleukin-6 and MDA decreased significantly. In addition, Isoeucommin A protected H O -stimulated renal tubular epithelial cells from oxidative stress and activated the Nrf2/HO-1 signaling pathway in high-glucose-stimulated human renal mesangial cells. In conclusion, Isoeucommin A could alleviate inflammation and oxidative stress in in vitro and in vivo DN models and thus attenuate kidney injury by activating the Nrf2/HO-1 signaling pathway. Isoeucommin A could have the potential to be used as an effective drug for the treatment of DN.
糖尿病肾病（DN）是糖尿病患者常见的并发症，也是主要的死亡原因。临床上对DN的管理仍然是一项挑战。因此，鉴定用于治疗DN的新型化合物并在临床前DN模型中对其进行表征至关重要。异杜仲苷A是从杜仲中分离出的一种木脂素化合物，尚未进行详细研究。我们的目的是研究异杜仲苷A对DN的影响，并阐明其在体外和体内发挥作用的分子机制。我们首先通过微孔树脂柱色谱法分离纯化了异杜仲苷A，并分别通过高分辨率电喷雾电离质谱和核磁共振研究了异杜仲苷A的质谱图及其结构。我们进一步建立了大鼠体内DN模型，并测量了用异杜仲苷A治疗后血糖、体重、肾指数（KI）、血尿素氮、肌酐（CRE）、谷胱甘肽、丙二醛（MDA）、超氧化物歧化酶（SOD）、白蛋白（ALB）以及尿ALB与CRE比值的变化。此外，我们通过定量实时聚合酶链反应和蛋白质印迹法测量了SOD、MDA、糖原合酶激酶-3β（GSK-3β）、磷酸化（p）-GSK-3β、核因子红细胞衍生2相关因子2（Nrf2）和血红素加氧酶-1（HO-1）的水平，并通过3-（4,5-二甲基噻唑-2-基）-2,5-二苯基溴化四氮唑试验评估细胞活力。用异杜仲苷A治疗后，DN大鼠的体重以及SOD、谷胱甘肽、HO-1和Nrf2的表达水平呈剂量依赖性增加。相反，血糖、KI、血尿素氮、CRE、尿ALB与CRE比值、肿瘤坏死因子-α、白细胞介素-1β、白细胞介素-6和MDA水平显著降低。此外，异杜仲苷A保护过氧化氢刺激的肾小管上皮细胞免受氧化应激，并在高糖刺激的人肾小球系膜细胞中激活Nrf2/HO-1信号通路。总之，异杜仲苷A可以减轻体外和体内DN模型中的炎症和氧化应激，从而通过激活Nrf2/HO-1信号通路减轻肾损伤。异杜仲苷A有可能成为治疗DN的有效药物。
