Role of intracellular complement activation in kidney fibrosis

细胞内补体激活在肾纤维化中的作用

• 批准号: 10264916
• 负责人: DIDIER PORTILLA
• 金额: $ 24.23万
• 依托单位: UNIVERSITY OF VIRGINIA
• 依托单位国家: 美国
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-09-19 至 2023-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10264916
• 关键词: Affect; Atlases; C3AR1 gene; Cell Survival; Cell physiology; Cells; Chronic Kidney Failure; Cicatrix; Clinical; Clinical Trials; Complement; Complement 5a; Complement Activation; Data; Data Set; Disease; End stage renal failure; Engineering; Epithelial Cells; Fibrosis; Genetic; Health; Inflammatory; Injury; Injury to Kidney; Invaded; Kidney; Kidney Diseases; Ligands; Metabolism; Morbidity - disease rate; Mus; Myeloid Cells; Natural Immunity; Nuclear RNA; Pathogenesis; Pathologic; Pathway interactions; Pericytes; Pharmaceutical Preparations; Phenotype; Physiology; Play; Population; Prevalence; Process; Proteomics; Reagent; Renal function; Risk; Role; Signal Transduction; System; T-Lymphocyte; Testing; Therapeutic; Tubular formation; United States; adaptive immunity; aging population; autocrine; cell type; complement system; cost; glomerulosclerosis; kidney cell; kidney fibrosis; kidney repair; macrophage; mortality; mouse model; nephrogenesis; paracrine; pathogen; receptor; recruit; renal scarring; transcriptome sequencing

PROJECT SUMMARY / ABSTRACT The prevalence of Chronic Kidney Disease (CKD) in the US is high and continues to rise in our aging population. Independent of the cause of CKD, tubulointerstitial fibrosis and glomerulosclerosis represent major pathways of progression of kidney disease, however, there are no approved drugs to treat kidney fibrosis that could ameliorate progression of CKD. In recent studies we demonstrated that locally synthesized and activated kidney complement components drive the pathogenesis of kidney fibrosis. The complement system is of major importance in innate and adaptive immunity, but dysregulated complement has been shown to play a major role in kidney injury. Our pilot data, leveraging single nuclear RNA sequencing (snRNAseq), indicate cell-specific compartmentation of complement components, particularly of C3 and C5 in RTE cells. Our data also indicate that these components ligand their cognate receptors, C3aR and C5aR1, on kidney macrophages in murine models of kidney fibrosis. In preliminary datasets, genetic deletion of these factors in a cell-specific manner imparted significant protection against renal scarring. Thus, the central hypothesis to be tested in this application is that intrinsic expression of complement components from kidney cells, their processing to active fragments and activation of their cognate receptors are key to the progressive loss of kidney function and scaring. This hypothesis will be investigated via the following independent, but complementary, specific aims: Aim 1: Delineate the intracellular expression of complement components by kidney cells. We will use snRNAseq in murine kidney fibrosis to delineate cell type-specific expression of complement components and their receptors. We will confirm data by proteomic approaches and identify the processing machinery generating active secretory fragments from complement components. Aim 2. Determine the importance of RTE-derived C3 for renal physiology and fibrosis. We will use mice engineered to lack C3 specifically in RTE cells to determine the relevance of intracellular complement for renal physiology and injury-induced fibrosis. We will study mice lacking the C3ar1 receptor on either kidney or myeloid cells to establish whether there is an obligate requirement for autocrine or paracrine C3 signaling. Aim 3. Determine the impact of C5a/C5aR1 axis activation on macrophages for the induction of kidney fibrosis or repair. We will validate our preliminary observations that macrophage-specific deletion of C5ar1 reduces fibrosis. We will determine whether C5ar1 directly affects macrophage phenotype and function, or whether C5ar1 macrophages promote scarring by recruiting and activating inflammatory T cells. Collectively, this proposal will establish a comprehensive atlas of complement component expression in kidney cells in healthy and injured kidneys, establish key mechanisms of these pathways in kidney scarring and enable clinical targeting of these pathways with therapeutically relevant strategies.

项目总结/摘要 美国慢性肾脏病（CKD）的患病率很高，并且在我们的老龄化人口中继续上升。 与CKD的病因无关，肾小管间质纤维化和肾小球硬化是CKD的主要途径。 然而，由于肾脏疾病的进展，没有批准的药物可以治疗肾脏纤维化， 改善CKD的进展。在最近的研究中，我们证明了局部合成和激活的肾脏 补体成分驱动肾纤维化的发病机制。补体系统主要 在先天性和适应性免疫中重要性，但失调的补体已被证明起主要作用 肾脏损伤我们的试验数据，利用单核RNA测序（snRNAseq），表明细胞特异性 补体成分的区室化，特别是RTE细胞中的C3和C5。我们的数据还表明 这些成分配体的同源受体，C3 aR和C5 aR 1，在小鼠肾巨噬细胞， 肾纤维化模型。在初步数据集中，这些因子以细胞特异性方式的遗传缺失 对肾瘢痕形成有显著的保护作用。因此，在本申请中待检验的中心假设 是来自肾细胞补体成分的内在表达，它们加工成活性片段 其同源受体的激活是肾功能进行性丧失和瘢痕形成的关键。这 将通过以下独立但互补的具体目标对假设进行研究：目标1： 肾细胞补体成分的细胞内表达。我们将在小鼠肾脏中使用snRNAseq 纤维化以描绘补体成分及其受体的细胞类型特异性表达。我们将确认 数据通过蛋白质组学的方法，并确定产生活性分泌片段的加工机制， 互补成分目标二。确定RTE衍生的C3对肾脏生理学和纤维化的重要性。 我们将使用在RTE细胞中特异性缺乏C3的小鼠来确定细胞内C3的相关性。 补充肾脏生理和损伤诱导的纤维化。我们将研究缺乏C3 ar 1受体的小鼠， 肾脏或骨髓细胞，以确定是否存在自分泌或旁分泌C3的专性需求 发信号。目标3.确定C5 a/C5 aR 1轴激活对巨噬细胞诱导肾 纤维化或修复。我们将验证我们的初步观察，巨噬细胞特异性C5 ar 1缺失 减少纤维化。我们将确定C5 ar 1是否直接影响巨噬细胞的表型和功能， C5 ar 1巨噬细胞是否通过募集和激活炎性T细胞促进瘢痕形成。总的来说， 该建议将建立健康人肾细胞中补体成分表达的综合图谱， 和损伤的肾脏，建立这些途径在肾瘢痕形成中的关键机制，并使临床靶向 这些途径的治疗相关策略。