Interactions of SERCA2a and BMPRII in Vascular Disease

肺动脉高压(PAH)的特征是肺血管阻力增加。 导致右室负荷过重，最终导致右室衰竭和过早死亡。这个 这种情况背后的病理机制仍不完全清楚。虽然确切的原因是 尽管多环芳烃的特征仍在调查中，但人们普遍认为，所有形式的PH的特征都是持续存在的 血管收缩、内皮功能障碍和血管重塑。肺动脉重塑是 以不同程度的肌肉血管内膜和中层增厚为特征的 钙离子变化引起的肺动脉平滑肌细胞的增殖和迁移 动态平衡。转化过程中锥形BMPR2基因的多种功能缺失突变 生长因子β(β)家族在细胞生长和纤维化中起关键作用，已被认为与 家族性和散发性的PAH病例居多。我们已经证明，肌浆网(Endo)中的钙离子- ATPase 2a(SERCA2a)泵在大鼠肺小动脉肥大中的表达 在PAH患者和野百合碱(MCT)诱导的PAH大鼠模型中。我们还发现SERCA2a BMPR2基因突变患者肥厚的肺动脉壁表达减少 在转基因SM22-tet-BMPR2delx4小鼠中，带有SMC特有的BMPR2突变形式，已知开发出 自发性PAH。腺病毒转导SERCA2a基因导致人PASMC减少 通过一种涉及STAT3/NFAT信号通路的机制进行增殖和迁移。此外，SERCA2a 过表达增加BMPR2、eNOS表达和活性，降低STAT3/NFAT活性 HPAEC。此外，使用雾化的腺相关病毒选择性地转导肺SERCA2a基因 MCT-PAH模型大鼠血清1型(AAV1.SERCA2a)可减轻肺动脉高压和右室肥厚， ENOS和BMPR2表达增加。根据初步调查结果，我们认为 SERCA2a和BMPR2在肺血管中相互依赖的下游信号转导机制 影响肺血管结构重塑并提示SERCA2a基因转移可能调节 BMPR2的表达和/或依赖的信号通路，从而导致PAH表型。为了测试这一点 假设我们将：1)表征肺血管细胞中SERCA2a和BMPR2之间的联系。2) 确定SERCA2特异性消融SMCs和ECs对小鼠PAH发病机制的影响。 3)探讨化学修饰信使对SERCA2a过表达的治疗作用 转基因动物模型中的RNA(ModRNA)。通过这项提议获得的知识是重要的。 因为通过调节SERCA2a的表达，我们将表征它在BMPR2表达和 因此在肺血管重塑和PAH表型中，这可能导致 寻找新的潜在靶点进行治疗干预以克服PAH的病理特征。

Pulmonary arterial hypertension (PAH) is characterized by an increase of pulmonary vascular resistance leading to right ventricular overload and eventually to right ventricular failure and premature death. The pathological mechanisms underlying this condition remains incompletely understood. While the exact causes of PAH remain under investigation, it is widely recognized that the hallmarks of all forms of PH are sustained vasoconstriction, endothelium dysfunction and vascular remodeling. Remodeling of pulmonary arteries is characterized to varying degrees by thickening of the intimal and medial layer of muscular vessels resulting from proliferation and migration of pulmonary arterial smooth muscle cells (PASMCs) with alterations in Ca2+ homeostasis. Diverse loss-of-function mutations in the conical BMPR2 gene, a component of the transforming growth factor beta (TGFβ) family that plays a key role in cell growth and fibrosis, have been associated with the majority of familial and sporadic cases of PAH. We have shown that sarco(endo)plasmic reticulum Ca2+- ATPase 2a (SERCA2a) pump expression is decreased in small hypertrophied pulmonary arterioles from patients with PAH and in a rat model of monocrotaline (MCT)-induced PAH. We also found that SERCA2a expression is reduced in hypertrophied pulmonary arterial wall of patients with underlying BMPR2 mutations and in transgenic SM22-tet-BMPR2delx4 mice, with a SMC-specific mutant form of BMPR2, known to develop spontaneous PAH. Gene transfer of SERCA2a by an adenovirus resulted in decreased human PASMC proliferation and migration via a mechanism involving STAT3/NFAT signaling pathways. In addition, SERCA2a overexpression increased BMPR2, eNOS expression and activity and decreased STAT3/NFAT activity in hPAEC. In addition, selective pulmonary SERCA2a gene transfer using aerosolized adeno-associated virus serotype 1 (AAV1.SERCA2a) in MCT-PAH rat model attenuate pulmonary hypertension and RV hypertrophy, and increased eNOS and BMPR2 expression. Based upon the preliminary findings we contend there is cross talk between SERCA2a and BMPR2 with interdependent downstream signaling in pulmonary vascular that affects pulmonary vascular structural remodeling and suggest that SERCA2a gene transfer may modulate BMPR2 expression and/or dependent signaling pathways and therefore PAH phenotype. To test this hypothesis we will: 1) Characterize the link between SERCA2a and BMPR2 in pulmonary vascular cells. 2) Determine the effects of SERCA2-specific ablation in SMCs & ECs on PAH pathogenesis in a mouse model. And 3) Investigate the therapeutic effects of SERCA2a overexpression using chemically modified messenger RNA (modRNA) in transgenic animal models. The knowledge acquired through this proposal is significant because by modulating SERCA2a expression, we will characterize its key role in BMPR2 expression and signaling and therefore in pulmonary vascular remodeling and PAH phenotype, that may lead to the identification of new potential targets for therapeutic intervention to overcome the pathological feature of PAH.