Molecular control of vascular smooth muscle reprogramming in arteriovenous fistula maturation

动静脉内瘘成熟过程中血管平滑肌重编程的分子控制

• 批准号: 10735849
• 负责人: Alan Dardik
• 金额: $ 71.93万
• 依托单位: AUGUSTA UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-07-01 至 2027-06-30
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10735849
• 关键词: ATAC-seq; Acute; Arteries; Arteriovenous fistula; Biochemical; Biological Assay; Blood Pressure; Blood Vessels; Cell Lineage; Cell Nucleus; Cell Proliferation; Cell Reprogramming; Cells; Chronic Kidney Failure; Clinical; Clonal Expansion; Complement Factor B; Complex; Data; Extracellular Matrix; Failure; Fistula; Future; Gel; Genes; Growth Factor; Healthcare Systems; Hemodialysis; Human; Hyperplasia; Impairment; In Situ Hybridization; Knockout Mice; Knowledge; Legal patent; Life; Ligation; MMP2 gene; Modification; Molecular; Mus; Nephrectomy; Nodal; Nuclear; Operative Surgical Procedures; Pathway interactions; Patients; Periodicity; Phenocopy; Phenotype; Pluronics; Procedures; Process; Property; Protein Isoforms; Regulation; Reporter; Role; Sampling; Sampling Studies; Signal Transduction; Smooth Muscle Myocytes; Specimen; Stenosis; Stress; Stretching; Testing; Thick; Time; Transactivation; Transducers; Vascular Smooth Muscle; Vascular remodeling; Veins; Venous; XCL1 gene; activating transcription factor 3; cell type; clinically relevant; design; factor A; hemodynamics; improved; inhibitor; insight; mouse model; myocardin; novel; pressure; programs; response; shear stress; success; targeted treatment; therapeutic target; transcription factor; transcriptome sequencing; transcriptomics

PROJECT SUMMARY A surgically created arteriovenous fistula (AVF) between an artery and vein is now the preferred approach to provide a vascular access for life-saving hemodialysis in chronic kidney disease CKD) patients. However, nearly 60% of AVFs fail to mature into a clinically useful conduit due to insufficient outward remodeling and flow capacity, occlusive neointimal hyperplasia, and/or fibrotic stenosis. Currently, there are no therapies that can improve AVF early maturation failure by enhancing AVF outward remodeling, largely due to our nascent understanding of the mechanisms underlying vein adaptations to AVF hemodynamic stresses. Acute increases in shear stress and pulsatile pressure in the vein are normalized by rapid dilation followed by wall thickening. Venous smooth muscle cells (vSMCs) are the predominant cells sensing vessel wall stretch in response to increased flow volume and blood pressure. A significant barrier to progress is a deficit in our knowledge of the mechanisms by which vSMCs respond to arterial hemodynamics in early AVF adaptation. Strong evidence from both AVF mouse models and human sample studies demonstrate, for the first time, a role for differentiated vSMCs in AVF outward remodeling and maturation. This is further supported by new preliminary data from our clinically relevant 5/6-nephrectomy CKD AVF mouse model. We further show early AVF maturation involves vSMCs reprogramming from a quiescent to a previously uncharacterized proliferative, synthetic state that surprisingly retains differentiated contractile properties. Myocardin related transcription factor (TF) A and B (MRTFA and B, MRTFs) respond to cyclic stretch by transactivating multiple gene programs. VSMC-deficiency of MRTFs impairs AVF maturation with reduced AVF wall thickness. Beyond the contractile gene program, MRTFA upregulates novel target genes (MMP2 and ATF3) to facilitate matrix remodeling and cell proliferation. This suggests that MRTFs act as nodal TFs of vSMC reprogramming. CAMK2 is a major signal transducer poised to integrate stretch-induced vascular remodeling. Preliminary data show growth factors induce nuclear interaction of CAMK2 and MRTFA in cultured vSMCs. VSMC-deficiency of a major VSMC CAMK2 isoform, CAMK2D, phenocopies loss of VSMC MRTFs, suggesting that CAMK2D transduces a signal(s) from AVF wall stress to trigger MRTF transactivity. These preliminary data support our central hypothesis that successful AVF adaptation and maturation involves CAMK2/MRTFs-dependent vSMC reprogramming to a proliferative, matrix organizing, and contractile phenotype. Aim1 will elucidate mechanisms of vSMC-dependent AVF adaptive remodeling and maturation using Itga8CreERT2Confetti reporter, single nucleus (sn) ATAC/RNA-seq, and spatial omics to determine vSMC clonal expansion and transcriptomics underlying AVF maturation. Aim 2 will use novel VSMC-specific MRTFs and CAMK2D knockout mice to elucidate the mechanistic role of CAMK2D/MRTFs in AVF maturation. Successful completion of these studies will provide novel insights into, and potential therapeutic targets for, AVF maturation failure attributable to inadequate vein adaption in humans.

项目概要 现在，通过手术在动脉和静脉之间建立动静脉瘘 (AVF) 是首选方法 为慢性肾病（CKD）患者提供挽救生命的血液透析血管通路。然而，几乎 由于向外重塑和流动不足，60% 的 AVF 未能成熟为临床上有用的导管 容量、闭塞性新内膜增生和/或纤维化狭窄。目前，尚无任何治疗方法可以 通过增强 AVF 外向重塑来改善 AVF 早期成熟失败，这主要是由于我们的新生 了解静脉适应 AVF 血流动力学压力的机制。急性增加 静脉中的剪切应力和脉动压力通过快速扩张和随后的壁增厚而正常化。 静脉平滑肌细胞 (vSMC) 是感知血管壁拉伸的主要细胞，以响应 血流量和血压增加。进步的一个重大障碍是我们对知识的缺乏 vSMCs 在早期 AVF 适应过程中对动脉血流动力学做出反应的机制。强有力的证据来自 AVF 小鼠模型和人类样本研究首次证明了分化的作用 AVF 中的 vSMC 向外重塑和成熟。我们的新初步数据进一步支持了这一点 临床相关的 5/6 肾切除 CKD AVF 小鼠模型。我们进一步表明早期 AVF 成熟涉及 vSMC 从静止状态重编程为以前未表征的增殖合成状态 令人惊讶的是保留了差异化的收缩特性。心肌素相关转录因子 (TF) A 和 B （MRTFA 和 B，MRTF）通过反式激活多个基因程序来响应循环拉伸。 VSMC缺乏症 MRTF 的减少会损害 AVF 的成熟，并减少 AVF 壁的厚度。除了收缩基因程序之外， MRTFA 上调新靶基因（MMP2 和 ATF3），以促进基质重塑和细胞增殖。 这表明 MRTF 充当 vSMC 重编程的节点 TF。 CAMK2 是主要的信号传感器 准备整合拉伸诱导的血管重塑。初步数据显示生长因子诱导核 CAMK2 和 MRTFA 在培养的 vSMC 中的相互作用。主要 VSMC CAMK2 异构体的 VSMC 缺陷， CAMK2D，VSMC MRTF 的表型丢失，表明 CAMK2D 转导来自 AVF 壁的信号 触发 MRTF 交易的压力。这些初步数据支持我们的中心假设，即成功的 AVF 适应和成熟涉及 CAMK2/MRTF 依赖性 vSMC 重编程为增殖性、 基质组织和收缩表型。 Aim1 将阐明 vSMC 依赖性 AVF 的机制 使用 Itga8CreERT2Confetti 报告基因、单核 (sn) ATAC/RNA-seq 进行自适应重塑和成熟， 和空间组学，以确定 AVF 成熟背后的 vSMC 克隆扩增和转录组学。目标2 将使用新型 VSMC 特异性 MRTF 和 CAMK2D 敲除小鼠来阐明 AVF 成熟中的 CAMK2D/MRTF。成功完成这些研究将提供新的见解，并且 由于人类静脉适应不足导致 AVF 成熟失败的潜在治疗靶点。