DACH1 transcriptomic regulation of glucocorticoid-responsive glomerular disease

DACH1 糖皮质激素反应性肾小球疾病的转录组调控

基本信息

批准号：
10338127
负责人：
Lewis Kaufman
金额：
$ 37.29万
依托单位：
ICAHN SCHOOL OF MEDICINE AT MOUNT SINAI
依托单位国家：
美国
项目类别：
财政年份：
2020
资助国家：
美国
起止时间：
2020-03-12 至 2025-01-31
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/10338127
关键词：
Adriamycin PFS Alleles Benefits and Risks Binding Binding Proteins Binding Sites Cell Line Clinical Data Disease Enhancers Event Focal Segmental Glomerulosclerosis Genes Genetic Genetic Polymorphism Genetic Transcription Genotype Glucocorticoid Receptor Glucocorticoids Goals Human In Vitro Injury Kidney Diseases Kidney Transplantation Knockout Mice Link Mediating Mus Mutation Nephrology Nephrotic Syndrome Outcome Patients Phenotype Predisposition Proteinuria Regulation Renal glomerular disease Reporter Resistance Signal Transduction Single Nucleotide Polymorphism Stratification Susceptibility Gene Testing Therapeutic Toxic effect Transgenic Mice Transplant Recipients Up-Regulation Work chromatin immunoprecipitation cohort design genome wide association study immunoregulation in vivo induced pluripotent stem cell mouse model novel novel therapeutic intervention overexpression patient subsets podocyte preservation promoter protective allele receptor binding resistance allele response risk variant systemic toxicity targeted treatment transcription factor transcriptome transcriptomics treatment choice

项目摘要

Project Summary: Podocyte injury is the causative event in all proteinuric kidney diseases including minimal change disease (MCD) and FSGS. Glucocorticoids (GCs) are often the initial and preferred treatment for these conditions. The beneficial effects of GCs are not caused by immunomodulation, but are mediated by their direct effects on podocytes. Unfortunately, GC therapy is riddled with severe systemic toxicities that limit their use. Identification of essential salutary GC-induced targets in podocytes might allow for new therapeutic approaches that can minimize toxicity but maintain efficacy. In the current proposal, we identified diminished expression of the transcription factor dachshund1 (DACH1) in a large-scale mutagenic screen designed to identify mutations that restored injury susceptibility to genetically injury-resistant podocytes. We found DACH1 to be essential to podocyte function in both novel global and podocyte-specific knock out mouse models. Importantly, podocyte- specific DACH1 heterozygous mice, which have reduced glomerular DACH1 expression levels similar to human MCD and FSGS patients, were remarkably susceptible to adriamycin nephropathy, and this phenotype was ameliorated by GC therapy. We found that GC administration caused early and significant induction of DACH1 expression, and we confirm binding of GC receptor to the DACH1 promoter by ChIP assay. Moreover, the protective allele of a DACH1 intronic SNP (rs626277), which has been identified in genome-wide association studies as linked to incident and prevalent CKD, introduced a GC-alpha transcription factor-binding site that was abrogated in the presence of the risk allele. When we tested these alleles in reporter studies, the protective allele dramatically augmented DACH1 promoter activity in response to GCs, consistent with GC- potentiated enhancer function. In GC treated kidney transplant patients, the protective rs626277 allele correlated closely with increased glomerular DACH1 expression and improvement in proteinuria. Furthermore, in a cohort of MCD and FSGS patients, protective and risk alleles correlated with GC responsiveness and resistance respectively. We hypothesize that DACH1 is a central transcriptomic regulator of the salutary glomerular GC response and that rs626277 genotype status, which modulates podocyte DACH1 transcription in the setting of GC therapy, is an important determinant of GC-responsiveness in nephrotic syndrome patients. Our proposal includes three specific aims: i) demonstrate that DACH1 over-expression is protective using a novel inducible podocyte-specific DACH1 transgenic mouse model ii) show that the beneficial effects of GCs in podocytes are mitigated in the absence of DACH1 expression using novel inducible podocyte-specific knockout mice iii) correlate rs626277 genotype status with clinical outcomes in GC-treated MCD and FSGS patients in NEPTUNE and cross-examine mechanistic and transcriptomic data obtained from the first two aims in these patients. If validated, rs626277 genotype status could serve to individualize risk-benefit stratification of GC therapy in nephrotic syndrome patients PRIOR to treatment initiation.

项目概要：足细胞损伤是所有蛋白尿性肾病（包括微小病变肾病）的致病事件（MCD）和 FSGS。糖皮质激素（GC）通常是这些病症的初始和首选治疗方法。这 GC 的有益作用不是由免疫调节引起的，而是由其直接作用介导的足细胞。不幸的是，GC 疗法存在严重的全身毒性，限制了其使用。鉴别足细胞中重要的 GC 诱导靶标的研究可能会带来新的治疗方法最大限度地减少毒性但保持疗效。在当前的提案中，我们发现表达减少转录因子 dachshund1 (DACH1) 在大规模诱变筛选中的作用，旨在识别突变恢复了对遗传抗损伤足细胞的损伤敏感性。我们发现 DACH1 对于新型整体和足细胞特异性敲除小鼠模型中足细胞的功能。重要的是，足细胞- 特定的 DACH1 杂合小鼠，其肾小球 DACH1 表达水平降低，类似于人类 MCD 和 FSGS 患者对阿霉素肾病非常敏感，并且这种表型 GC治疗后症状得到改善。我们发现 GC 给药引起了早期和显着的诱导 DACH1 表达，我们通过 ChIP 测定确认 GC 受体与 DACH1 启动子的结合。而且， DACH1 内含子 SNP (rs626277) 的保护性等位基因，已在全基因组中鉴定与事件和流行的 CKD 相关的关联研究引入了 GC-α 转录因子结合在存在风险等位基因的情况下被废除的位点。当我们在记者研究中测试这些等位基因时，保护性等位基因显着增强了响应 GC 的 DACH1 启动子活性，这与 GC-一致增强的增强子功能。在 GC 治疗的肾移植患者中，保护性 rs626277 等位基因与肾小球 DACH1 表达增加和蛋白尿改善密切相关。此外，在一组 MCD 和 FSGS 患者中，保护性和风险等位基因与 GC 反应性相关分别为电阻。我们假设 DACH1 是有益的转录组调控因子肾小球 GC 反应和 rs626277 基因型状态，调节足细胞 DACH1 转录在 GC 治疗中，是肾病综合征 GC 反应性的重要决定因素患者。我们的提案包括三个具体目标：i) 证明 DACH1 过度表达具有保护作用使用新型诱导足细胞特异性 DACH1 转基因小鼠模型 ii) 表明，在缺乏 DACH1 表达的情况下，使用新型诱导性足细胞特异性药物可减轻足细胞中的 GC 敲除小鼠 iii) 将 rs626277 基因型状态与 GC 治疗的 MCD 和 FSGS 的临床结果相关联 NEPTUNE 中的患者并交叉检查从前两个目标获得的机制和转录组数据在这些患者中。如果得到验证，rs626277 基因型状态可以用于个体化风险收益分层肾病综合征患者在治疗开始前进行 GC 治疗。