Modulating BMPRII Signaling in Pulmonary Arterial Hypertension

描述(由申请人提供)：项目摘要/摘要：我的提案的主要目标是发现调制BMPRII信令的途径。这一信号通路与肺动脉高压(PAH)有关，PAH是一种如果不治疗就会导致右心衰竭和死亡的疾病。70%的家族性和20%的特发性(I-)PAH患者携带骨形态发生蛋白受体(BMPR)-II的突变。但开发多环芳烃的渗透率不到20%。最近的研究表明，野生型BMPRII等位基因水平的降低会区分受影响的家庭成员和未受影响的家庭成员。即使是PAH合并其他疾病(APAH)也可伴有BMPRII蛋白表达降低。在一些IPAH患者中发现了BMPRII蛋白的下调，但不是mRNA的下调，这表明了一种转录后调控机制，这可能也适用于许多没有突变的IPAH患者。因此，一种可能最终导致预防和治疗肺动脉高压的新方法可能是恢复BMPRII信号。MicroRNAs参与基因表达的转录后调控，尤其是microRNA21(miR-21)可以靶向BMPRII mRNA。在具体目标1中，我们将使用miR-21模拟物和抗激动子来调节人肺动脉内皮细胞(PAECS)和平滑肌细胞(PASMCs)以及从BMPRII水平降低的小鼠分离的细胞中miR-21和BMPRII的水平。此外，我们将通过增加BMPRII来确认BMP信号和功能对BMP的响应得到恢复。具体目标2是通过筛选可以增强BMPRII信号的药理活性化合物，寻求第二种非常有希望的途径来增加BMP信号转导。我们将使用FDA批准的3,600种药理活性化合物开发高通量筛选(HTS)。除了增强BMP信号的“HITS”，我们还将识别通过BMPRII受体抑制信号的分子，因此可能对IPAH患者和BMPRII表达受损的未受影响的家庭成员有害。我们将再次验证响应BMP的BMP信号和功能将增加。这些结果为特定的目标3奠定了基础，在那里我们将首先使用miR-21反配子以及在HTS中发现的潜在的“BMP激活剂”来增加体内的BMPRII信号，即。在BMPRII杂合子小鼠中。其次，我们将证明上述方法将防止或逆转BMPRII杂合子小鼠(受低氧和5-羟色胺刺激)的实验性PAH。我们的最终目标是启动一项具有最佳疗效/副作用的化合物的临床试验。有机会调节相关microRNAs的水平，并找到FDA批准的药物，通过恢复正常的BMP信号来阻止进展或逆转PH，这将是一项重大突破。

DESCRIPTION (provided by applicant): Project summary/ Abstract: The main goal of my proposal is uncover avenues that modulate BMPRII signaling. This signaling pathway is relevant in pulmonary arterial hypertension (PAH), a disease leading if untreated, to right heart failure and death. 70% of patients with familial and 20% of patients with idiopathic (I-) PAH carry a mutation in the bone morphogenetic protein receptor (BMPR)-II. However, the penetrance to develop PAH is less than 20%. Recent studies have shown that reduced levels of the wild-type BMPRII allele discriminate between affected and non- affected family members. Even PAH associated with other diseases (APAH) can be accompanied by reduced protein expression of BMPRII. Downregulation of BMPRII protein, but not mRNA, has been described in some IPAH patients, suggesting a post-transcriptional mechanism of regulation and this may also be true for the many IPAH patients without mutations. Therefore a novel approach that might ultimately lead to the prevention and treatment of pulmonary hypertension could be restoration of BMPRII signaling. Micro RNAs are involved in posttranscriptional regulation of gene expression, and microRNA 21 (miR-21) in particular can target BMPRII mRNA. In Specific Aim 1 we will use miR-21 mimics and antagomirs to modulate the levels of miR-21 and BMPRII in human pulmonary artery endothelial cells (PAECS) and smooth muscle cells (PASMCs) as well as in cells isolated from a mouse with reduced BMPRII levels. In addition we will confirm that BMP signaling and function in response to BMPs are restored by increasing BMPRII. Specific Aim 2 is to pursue a second very promising avenue to increase BMP signaling by screening for pharmacologically active compounds that could enhance signaling via BMPRII. We will develop a High Throughput Screen (HTS) using 3,600 FDA approved pharmacologically active compounds. In addition to "hits" that enhance BMP signaling, we will identify molecules that inhibit signaling through the BMPRII receptor and could therefore be harmful in IPAH patients and non-affected family members with compromised BMPRII expression. We will again verify that BMP signaling and function in response to BMP will be increased. These results set the stage for Specific Aim 3, where we will first use miR-21 antagomirs as well as a potential "BMP activator" identified in the HTS to increase BMPRII signaling in vivo, ie. in mice heterozygous for BMPRII. Second we will show that the above approach will prevent or reverse experimental PAH in BMPRII heterozygous mice (stimulated with hypoxia and Serotonin). Our ultimate goal is to initiate a clinical trial with the compound with the best efect/side-effect profile. The opportunity to modulate levels of relevant microRNAs and to identify a FDA approved drug that could arrest the progression or reverse PH by restoring normal BMP signaling would be a major breakthrough.