Role of AMP-kinase pathway in the regulation of Minimal change disease-to-FSGS transition

AMP-激酶途径在微小病变向 FSGS 转变调节中的作用

• 批准号: 10585051
• 负责人: Madhav C Menon
• 金额: $ 55.56万
• 依托单位: YALE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-12-15 至 2027-11-30
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10585051
• 关键词: 1 year old; Actins; Adriamycin PFS; Albuminuria; Autophagocytosis; Biological Models; Biopsy; Case Series; Case Study; Cell Survival; Cytoplasm; Cytoskeleton; Data; Diagnostic; Diagnostic Procedure; Diffuse; Dimensions; Disease; End stage renal failure; Event; FDA approved; FYN gene; Focal and Segmental Glomerulosclerosis; Foot Process; Genetic; Genetic Models; Growth; Human; Hypertrophy; In Vitro; Injury; Investigation; Kidney Failure; Mediating; Modeling; Morphology; Multiple Trauma; Mus; Nephrectomy; Nephrotic Syndrome; Pathology; Pathway interactions; Phenotype; Phosphotransferases; Proteinuria; Proteomics; Proto-Oncogene Proteins c-fyn; Regulation; Role; STK11 gene; Signal Transduction; Stress; Technology; Testing; Therapeutic; Toxin; Visualization; Work; adenylate kinase; aged; biobank; cohort; design; glomerulosclerosis; in vitro Model; in vivo; inhibition of autophagy; injured; innovation; knock-down; morphometry; novel; novel therapeutics; overexpression; pharmacologic; podocyte; preservation; prevent; prognostic value; protective effect; response; self-renewal; transcriptomics

Project Summary: Nephrotic syndrome (NS) is characterized by proteinuria and is associated with podocyte actin cytoskeletal disorganization termed foot process effacement (FPE). Podocytes are incapable of self- renewal, and podocyte loss above~40% per glomerulus associates with glomerulosclerosis (FSGS) and kidney failure. Distinct from FSGS, Minimal Change Disease (MCD) also shows diffuse FPE, but has preserved podocyte numbers, and is highly treatment responsive with a low rate of progression to ESRD (5-20% in 20 years). FSGS has been associated with glomerulomegaly and podocyte hypertrophy in later stages. However, early FSGS can be morphologically indistinguishable from MCD and a debate exists whether some MCD cases transition to FSGS, representing a “switch” between diseases. Hence, understanding signals specific to MCD will reveal mechanisms facilitating podocyte survival and preventing a phenotype “switch”. Interestingly, Fyn kinase inactivation was specifically identified in human MCD. In mice, Fyn inactivation (by Shroom3 silencing) also associated with FPE without podocytopenia - an “MCD-like” pathology. Hence Fyn inactivation was a candidate MCD-unique signal. Downstream of Fyn-inactivation, investigation of anti-hypertrophy and pro- survival pathways in podocytes revealed enhanced activation of AMP-kinase, explaining these effects. Fyn inactivation activated AMPK by increasing cytoplasmic efflux of LKB1. Moreover, inhibition of Ampk in MCD-like mice induced podocyte loss, glomerulomegaly and FSGS, while AMPK activation prevented podocyte loss after glomerular injury induced by hypertrophy and direct toxins. Invitro data show increased autophagy as the central pro-survival mechanism in podocytes after AMPK-activation. We hypothesize that in the context of injury causing podocyte FPE, AMPK signaling regulates the “switch” between MCD and FSGS by enhancing autophagy and preventing podocytopenia. In this proposal, we will test the role of podocyte AMPK signaling in MCD vs FSGS, and establish downstream mechanisms regulating podocyte survival. In Aim I, we will use genetic and pharmacologic model systems to specifically inactivate or activate AMPK to induce phenotype changes from MCD-to-FSGS and vice versa. In Aim-II, we will modulate autophagy in podocytes while activating AMPK to show the central role of AMPK-mediated autophagy in podocyte survival. We will also specifically examine the role of autophagy in restricting glomerulomegaly during injury. Finally, in Aim-III, applying state-of-the-art and multidimensional technologies to the largest NS cohort in the US, we will investigate the specific role of AMPK signaling in human MCD vs FSGS. Our work will provide novel MCD-FSGS diagnostics, and develop novel AMPK therapeutics as well as help repurpose FDA-approved AMP-activators.

项目摘要：肾病综合征(NS)以蛋白尿为特征，与足细胞相关 肌动蛋白细胞骨架紊乱称为足突消失(FPE)。足细胞不能自我 更新，每个肾小球足细胞丢失超过40%与肾小球硬化(FSGS)和肾脏相关 失败了。与FSGS不同，微小病变(MCD)也表现为弥漫性FPE，但已保存 足细胞数量多，治疗反应快，进展到终末期肾病的比率很低(20%-5% 年)。FSGS与晚期肾小球肥大和足细胞肥大有关。然而， 早期的FSGS在形态上与MCD没有区别，一些MCD病例是否存在争议 过渡到FSGS，代表着疾病之间的“切换”。因此，理解MCD特有的信号 将揭示促进足细胞存活和防止表型“转换”的机制。有趣的是，Fyn 激酶失活是在人类MCD中特异发现的。在小鼠中，Fyn失活(通过Shroom3沉默) 也与无足细胞减少的FPE有关--一种“MCD样”病理。因此，FYN失活是一种 候选MCD-唯一信号。FYN下游失活、抗肥厚和促肥厚作用的研究 足细胞中的生存途径显示AMP-激酶的激活增强，这解释了这些效应。芬恩 失活通过增加LKB1胞浆外流而激活AMPK。此外，AMPK在类MCD中的抑制作用 小鼠导致足细胞丢失、肾小球增大和FSGS，而AMPK激活阻止了足细胞丢失 肥大和直接毒素所致的肾小球损伤。体外数据显示自噬增加作为中枢 AMPK激活后足细胞的促存活机制。我们假设在造成伤害的情况下 足细胞FPE、AMPK信号通过增强自噬和调节MCD和FSGS之间的“切换” 预防足红细胞减少症。在这个方案中，我们将测试足细胞AMPK信号在MCD和FSGS中的作用， 并建立调控足细胞存活的下游机制。在AIM I中，我们将使用基因和 特异性灭活或激活AMPK以诱导表型变化的药物模型系统 MCD到FSGS，反之亦然。在AIM-II中，我们将在足细胞中调节自噬，同时激活AMPK以 显示AMPK介导的自噬在足细胞存活中的中心作用。我们还将专门研究 自噬在限制损伤过程中肾小球增大中的作用。最后，在AIM-III中，应用最先进的和 美国最大的NS队列，我们将调查AMPK的具体作用 人类MCD与FSGS中的信号转导。我们的工作将提供新的MCD-FSGS诊断方法，并开发新的 AMPK疗法以及帮助重新调整FDA批准的AMP激活剂的用途。