Genetic and Pharmacologic Targeting of Glycogen Synthase Kinase 3β Reinforces the Nrf2 Antioxidant Defense against Podocytopathy
Genetic and Pharmacologic Targeting of Glycogen Synthase Kinase 3β Reinforces the Nrf2 Antioxidant Defense against Podocytopathy
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DOI：
10.1681/asn.2015050565
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发表时间：
2016-08-01
影响因子：
13.6
通讯作者：
Gong, Rujun
中科院分区：
文献类型：
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作者：
Zhou, Sijie;Wang, Pei;Gong, Rujun
有证据表明，糖原合成酶激酶3（GSK 3）决定的核排斥和Nrf 2的降解是关闭损伤后的自我保护性抗氧化应激反应的关键。在这里，我们研究了肾小球疾病中这种调节的机制。在原代足细胞中，多柔比星引起细胞死亡和肌动蛋白细胞骨架解体，伴随着GSK 3 β（肾小球足细胞中表达的主要GSK 3亚型）的过度活化和最小的Nrf 2活化。SB 216763是一种高选择性的GSK 3小分子抑制剂，其发挥的保护作用依赖于增强的Nrf 2抗氧化反应，其特征在于Nrf 2表达和核积累增加以及Nrf 2靶向血红素加氧酶-1的产生增加。在培养的足细胞中GSK 3 β激酶死亡突变体的异位表达增强了阿霉素诱导的Nrf 2活化并防止足细胞损伤。相反，组成型活性GSK 3 β突变体减弱了阿霉素诱导的Nrf 2反应，并加剧了足细胞损伤，这可以通过SB 216763治疗来消除。在多柔比星肾病或肾毒性血清肾炎的小鼠模型中，通过强力霉素诱导的足细胞特异性敲除或SB 216763的药理学靶向作用对GSK 3 β进行遗传靶向，可显著减轻白蛋白尿，并改善足细胞损伤的组织学体征，包括足细胞减少症、足细胞标志物丢失、足细胞结蛋白从头表达和足细胞病的超微结构病变（如足突消失）。这种有益的结果可能归因于肾小球足细胞中增强的Nrf 2抗氧化反应，因为选择性Nrf 2拮抗剂胡芦巴碱消除了蛋白尿减少和足细胞保护作用。总的来说，我们的研究结果表明，GSK 3 β调节的Nrf 2抗氧化反应作为一种新的治疗靶点，用于保护足细胞和治疗蛋白尿性肾小球病。
Evidence suggests that the glycogen synthase kinase 3 (GSK3)-dictated nuclear exclusion and degradation of Nrf2 is pivotal in switching off the self-protective antioxidant stress response after injury. Here, we examined the mechanisms underlying this regulation in glomerular disease. In primary podocytes, doxorubicin elicited cell death and actin cytoskeleton disorganization, concomitant with overactivation of GSK3 beta (the predominant GSK3 isoform expressed in glomerular podocytes) and minimal Nrf2 activation. SB216763, a highly selective small molecule inhibitor of GSK3, exerted a protective effect that depended on the potentiated Nrf2 antioxidant response, marked by increased Nrf2 expression and nuclear accumulation and augmented production of the Nrf2 target heme oxygenase-1. Ectopic expression of the kinase-dead mutant of GSK3 beta in cultured podocytes reinforced the doxorubicin-induced Nrf2 activation and prevented podocyte injury. Conversely, a constitutively active GSK3 beta mutant blunted the doxorubicin-induced Nrf2 response and exacerbated podocyte injury, which could be abolished by treatment with SB216763. In murine models of doxorubicin nephropathy or nephrotoxic serum nephritis, genetic targeting of GSK3 beta by doxycycline-inducible podocyte-specific knockout or pharmacologic targeting by SB216763 significantly attenuated albuminuria and ameliorated histologic signs of podocyte injury, including podocytopenia, loss of podocyte markers, podocyte de novo expression of desmin, and ultrastructural lesions of podocytopathy (such as foot process effacement). This beneficial outcome was likely attributable to an enhanced Nrf2 antioxidant response in glomerular podocytes because the selective Nrf2 antagonist trigonelline abolished the proteinuria-reducing and podocyte-protective effect. Collectively, our results suggest the GSK3 beta-regulated Nrf2 antioxidant response as a novel therapeutic target for protecting podocytes and treating proteinuric glomerulopathies.