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

• 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
• 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

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病因 (MCD)和FSGS。糖皮质激素（GC）通常是这些疾病的初始和首选治疗。的 GC的有益作用不是由免疫调节引起的，而是由其对免疫系统的直接作用介导的。 足细胞不幸的是，GC疗法充满了严重的全身毒性，限制了它们的使用。识别 足细胞中必需的有益的GC诱导的靶点可能允许新的治疗方法， 最大限度地减少毒性，但保持疗效。在目前的提案中，我们确定了减少表达的 转录因子dachshund 1（DACH 1）在一个大规模的诱变筛选，旨在确定突变， 恢复了对遗传损伤抗性足细胞的损伤易感性。我们发现DACH 1对于 足细胞在新的整体和足细胞特异性敲除小鼠模型中的功能。重要的是，足细胞- 特异性DACH 1杂合子小鼠，其肾小球DACH 1表达水平降低，类似于 人MCD和FSGS患者对阿霉素肾病非常敏感，这种表型 经GC治疗后，我们发现，GC给药引起早期和显著的诱导， DACH 1表达，我们通过ChIP测定证实GC受体与DACH 1启动子的结合。此外，委员会认为， DACH 1内含子SNP（rs626277）的保护性等位基因，已在全基因组中鉴定 与CKD发病和流行相关的研究，引入了GC-α转录因子结合蛋白， 该位点在风险等位基因存在时被废除。当我们在报告者研究中测试这些等位基因时， 保护性等位基因显著增强了DACH 1启动子对GC的反应活性，与GC-1一致。 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DACH 1表达增加和蛋白尿改善密切相关。此外，委员会认为， 在MCD和FSGS患者队列中，保护性和风险等位基因与GC反应性相关， 分别抵抗。我们假设DACH 1是一个中央转录组调节器的有益 肾小球GC反应和调节足细胞DACH 1转录rs626277基因型状态 在GC治疗中，是肾病综合征GC反应性的重要决定因素 患者我们的建议包括三个具体目标：i）证明DACH 1过表达是保护性的， 使用新的可诱导足细胞特异性DACH 1转基因小鼠模型ii）表明， 在缺乏DACH 1表达的情况下，使用新的可诱导足细胞特异性免疫抑制剂减轻足细胞中的GC 基因敲除小鼠iii）将rs626277基因型状态与GC处理的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中获得的机制和转录组学数据 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-获益分层， 肾病综合征患者在治疗开始前的GC治疗。