Mechanisms of C3 effects in ARPKD pathogenesis

C3 在 ARPKD 发病机制中的作用机制

• 批准号: 8713990
• 负责人: Michal Mrug
• 金额: $ 31.97万
• 依托单位: UNIVERSITY OF ALABAMA AT BIRMINGHAM
• 依托单位国家: 美国
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-08-05 至 2018-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8713990
• 关键词: Address; Affect; Antigen-Antibody Complex; Applications Grants; Attenuated; Autosomal Dominant Polycystic Kidney; Autosomal Recessive Polycystic Kidney; Breeding; C3bi; CCL2 gene; CD14 gene; Cell Line; Cell Proliferation; Cell physiology; Cells; Child; Complement; Complement 3; Complement Receptor; Cyst; Cystic kidney; DNA; Data; Defect; Development; Disease; Disease Outcome; Disease Progression; Disease model; End stage renal failure; Epigenetic Process; Epithelial Cells; Epithelium; Figs - dietary; Foundations; Gap Junctions; Generations; Genomics; ITGAM gene; Immune; In Vitro; Inherited; Injury; Integrins; Kidney; Knowledge; Lead; Link; Macrophage-1 Antigen; Messenger RNA; Modeling; Mus; Mutation; Pathogenesis; Pathway interactions; Patients; Pharmaceutical Preparations; Phenocopy; Play; Polycystic Kidney Diseases; Process; Production; Prognostic Marker; Proteins; Proteomics; Rattus; Reagent; Regulation; Renal tubule structure; Research; Research Design; Role; SRC gene; Source; Supportive care; TNF gene; Testing; Therapeutic; Tubular formation; Up-Regulation; advanced disease; base; complement pathway; fluid flow; genome-wide; inhibitor/antagonist; innovation; knowledge base; macrophage; monocyte; novel; pre-clinical; prognostic; public health relevance; receptor; research study; response; response to injury; therapeutic target

DESCRIPTION (provided by applicant): This grant application addresses the role of complement component 3 (C3), an axial component of complement pathway, in the pathogenesis of autosomal recessive polycystic kidneys disease (ARPKD), the most severe form of polycystic kidney disease (PKD). In line with paradigm shifts resulting from discoveries of novel essential roles of local C3 production, our studies point to intra-renal production of C3 as a regulator of a cystogenic pathway that dictates the pace of ARPKD progression. We formulated this hypothesis based on our genome-wide expression analyses of kidneys with rapid verses slow pace of cystogenesis in Cys1cpk/cpk model which phenocopies ARPKD. We supported this hypothesis by demonstrating: (i) increased content of biologically active split C3 fragments in kidneys from ARPKD and its orthologous model; (ii) presence of C3 mRNA and protein in renal cystic and pericystic cells; and (iii) strong association between renal C3 expression and pace of renal cystogenesis that we validated in crosses of C3 deficient (C3-/-) mice with Cys1cpk/+ mice. In addition, cystogenesis is attenuated in Pkhd1pck rats' introgressed to a strain with low C3 expression. While C3 may act through different pathways, we have found consistent association of accelerated cystogenesis specifically with the pathway regulated by complement receptor CR3. CR3 (or Mac-1), a major receptor for C3 fragment iC3b, which is highly abundant in cystic kidneys, plays a central role in differentiation, attachment and survival of monocytes/macrophages. While we have identified C3, macrophage marker CD14 and C3-inducible factor MCP-1 as candidate predictors of PKD outcomes, others have demonstrated that macrophage depletion attenuates cystogenesis in orthologous models of autosomal dominant PKD by reducing the proliferation of cystic tubules. CR3 may also induce pro-cystogenic TNF release and directly activate c-Src in renal tubule cells. Consistent with essential and novel effects of local complement factor production, the capacity of renal tubule cells to produce and activate C3 and dysregulation of this process by a cystogenic defect, we suggest that the C3 effects in ARPKD increase as cystic tubules dilate, forming a vicious cystogenic cycle. Specifically, we hypothesize that C3 pathway activation accelerates cyst formation in ARPKD through a CR3 dependent process. We address this hypothesis in three inter-related aims: 1) Dissect mechanisms underlying cystogenic effects of C3; 2) Determine whether C3 production by Pkhd1-expressing cells modulates ARPKD pathogenesis; and 3) Determine the role of complement component receptor CR3 (or Mac1) in renal cystogenesis. Objectives of these Aims will be accomplished by integrating: (i) highly innovative study design of interrogating novel regulatory mechanisms of renal cystogenesis with (ii) generation of novel state of the art reagents (e.g., for conditional C3 targeting). Achieving these aims will: (i) allo integration of existing knowledge by linking established and novel cystogenic pathways to the C3-CR3 nexus, and (ii) provide a new direction in ARPKD research that may lead to development of novel prognostic and therapeutic strategies.

描述（由申请人提供）：本赠款申请介绍了补体组件3（C3）的作用，这是补体途径的轴向成分，在常染色体隐性膜性多囊肾脏病（ARPKD）的发病机理中，这是最严重的多囊性肾脏病（PKD）。与局部C3生产的新基本作用有关的范式变化一致，我们的研究表明，C3的肾脏产生是决定ARPKD进展速度的囊肿途径的调节剂。我们基于在Cys1CPK/CPK模型中快速的肾脏的肾脏对肾脏的全基因组表达分析提出了这一假设，该肾脏慢速囊肿发生了。我们通过证明：（i）来自ARPKD肾脏及其直系同源模型的生物活性分裂C3片段的含量增加； （ii）在肾囊性和周细胞细胞中存在C3 mRNA和蛋白质； （iii）我们在C3缺乏（C3 - / - ）小鼠中与Cys1cpk/+小鼠在C3缺乏（C3 - / - ）小鼠中验证的肾脏C3表达与肾脏囊肿的速度之间的牢固关联。此外，在PKHD1PCK大鼠中降低了囊肿发生，使C3表达较低的菌株渗入。尽管C3可能通过不同的途径起作用，但我们发现加速的胞质发生的稳定关联是专门与补体受体CR3调节的途径。 CR3（或MAC-1）是C3片段IC3B的主要受体，在囊性肾脏中高度丰富，在分化，附着和单核细胞/巨噬细胞的分化，附着和存活中起着核心作用。尽管我们已经确定了C3，巨噬细胞标记CD14和C3诱导因子MCP-1是PKD结果的候选预测指标，但其他人则证明，巨噬细胞的耗竭可通过减少囊肿小组的膨胀来降低常染色体显性PKD的直系同源模型中的囊肿。 CR3还可以诱导促源性TNF释放，并直接激活肾小管细胞中的C-SRC。与局部补体因子产生的基本和新颖的作用一致，肾小管细胞的能力通过细胞遗传缺陷而产生和激活C3和该过程的失调，我们建议随着囊性小管的扩张，ARPKD中的C3效应会增加，形成恶性细胞源性周期。 具体而言，我们假设C3途径激活通过CR3依赖性过程加速了ARPKD中的囊肿形成。我们以三个相互关联的目的解决了这一假设：1）C3的囊肿效应的基础机制； 2）确定表达PKHD1的细胞产生C3是否调节ARPKD发病机理； 3）确定补体成分受体CR3（或MAC1）在肾囊肿发生中的作用。这些目标的目标将通过集成来实现：（i）高度创新的研究设计，审问了肾脏囊肿发生的新型调节机制，以及（ii）（ii）新型最先进的试剂（例如，针对有条件的C3靶向）。实现这些目标将：（i）通过将已建立和新颖的膀胱遗传途径与C3-CR3 Nexus联系起来，以及（ii）在ARPKD研究中提供了新的方向，这可能会导致新的预后和治疗策略的发展。