Regulation of BMP2 in CKD Induced Calcification in the Klotho Aging Model

 描述(申请人提供)：本项目的目标是了解衰老和慢性肾脏疾病(CKD)如何促进骨形态发生蛋白2(BMP2)的合成，从而进一步促进心脏瓣膜和血管系统的病理性钙化。转录后调控机制抑制BMP2在主动脉和主动脉瓣中的表达。我们假设(1)这种抑制对于控制成人的BMP2水平是必不可少的，(2)衰老和慢性肾脏病等情况损害了调节健康心脏瓣膜和主动脉中这种抑制的因子的功能。我们将在老年正常小鼠(24个月)和模拟年龄相关疾病的Klotho零小鼠(包括CKD)中测试这些假设。Klotho基因缺失的小鼠会过早衰老，并在7-8周大时死亡。此时，心脏瓣膜、血管和其他软组织发生了广泛的钙化。目的1检测条件性缺失BMP2基因3‘非翻译区(UTR)强抑制元件对正常衰老小鼠和Klotho缺失型早衰及衰老相关肾功能障碍小鼠钙化的影响。我们将使用最近开发的BMP2等位基因来评估这种有效的转录后抑制因子的缺失如何影响与衰老和肾功能障碍相关的钙化过程。目的2是识别年轻、健康的主动脉和主动脉瓣特有的miRNA信号，并将其与来自正常衰老小鼠和Klotho基因缺失小鼠的这些组织的信号进行比较。在这些简介中，我们将专注于转录后抑制因子(MiRNAs)，这些因子针对BMP2 UCS，并在健康组织中参与3‘UTR介导的抑制。目的3是测试选择和实验验证的miRNAs如何影响BMP2的表达和下游成骨事件，从而导致携带我们独特转基因的Klotho缺失小鼠的钙化。我们的新型BMP2报告小鼠将加快旨在防止病理性钙化的miRNA疗法的临床前测试。我们新开发的BMP2等位基因(AIM 1)将区分这些针对BMP2的miRNAs相对于非靶标基因的变化。拟议研究的结果将是(1)增加对BMP2如何影响病理性钙化的了解，(2)识别和分析潜在的miRNA生物标记物，以及(3)控制病理性钙化的新的治疗线索。

 DESCRIPTION (provided by applicant): The goal of this project is to understand how aging and chronic kidney disease (CKD) promote bone morphogenetic protein 2 (BMP2) synthesis that furthers pathological calcification of the heart valves and vasculature. Post-transcriptional regulatory mechanisms repress BMP2 in aorta and aortic valve. We hypothesize that (1) this repression is essential for controlling BMP2 levels in the adult and that (2) conditions such as aging and CKD impair the function of factors that mediate this repression in healthy heart valves and aorta. We will test these hypotheses in aged normal mice (24 months) and in the Klotho null mouse which models age-related disorders, including CKD. Klotho null mice suffer premature aging and death occurs at 7 - 8 weeks of age. At this time, extensive calcification of the heart valves, vasculature, and other soft tissues has occurred. AIM 1 is to test the influence of conditionally deleting a strong repressive element in the 3'untranslated region (UTR) of Bmp2 on calcification in normal aged mice and in Klotho null mice with premature aging and aging associated renal dysfunction. We will use recently developed Bmp2 alleles to assess how the deletion of this potent post-transcriptional repressor influences the course of calcification associated with aging and renal dysfunction. AIM 2 is to identify and compare miRNA signatures unique to young, healthy aorta and aortic valve to the signatures of these tissues from normal aged mice and in Klotho null mice with premature aging and severe vascular calcification. Within these profiles, we will focus on post- transcriptional repressive factors (miRNAs) that target the Bmp2 UCS and contribute to 3'UTR mediated repression in healthy tissues. AIM 3 is to test how selected and experimentally validated miRNAs influence the expression Bmp2 and downstream osteogenic events that lead to calcification in Klotho null mice bearing our unique transgenes. Our novel Bmp2 reporter mouse will expedite pre-clinical testing of miRNA therapies designed to prevent pathological calcification. Our newly developed Bmp2 allele (Aim 1) will differentiate changes due these miRNAs targeting Bmp2 relative to off-target genes. The outcomes of the proposed research will be (1) increased understanding of how BMP2 influences pathological calcification, (2) the identification and analyses of potential miRNA biomarkers, and (3) new therapeutic leads for controlling pathological calcification.