Rapamycin induced Inhibition of aortic elastolysis in a murine model of marfan syndrome

雷帕霉素诱导抑制马凡综合征小鼠模型中的主动脉弹性溶解

• 批准号: 421971899
• 负责人: Dr. Marcin Zaradzki
• 金额: --
• 依托单位: Chirurgische Klinik (Zentrum)
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2019
• 资助国家: 德国
• 起止时间: 2018-12-31 至 2021-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/421971899?language=en
• 关键词: Rapamycin; induced; Inhibition; aortic; elastolysis

Marfan syndrome is a complex genetic disorder with a pleiotropy of symptoms caused by a mutation in the fibrillin-1 gene. The leading symptoms are vascular disorders, lens luxations and skeletal deformations. There is still no systemic therapy for the life threatening complications like aortic aneurysms and dissections. The pathophysiology of this disease’s vascular components can be explained by instability of the microfibrils in the aortic media. The instability is due to an abnormally high expression and activity of matrix metallo proteinases (MMP) from the aortic smooth muscle cells in the media. This group of enzymes degrades the elastin fibers and through a fragmentation of the microfibrils leads to a higher TGF-β bioavailability. All of these findings ultimately cause a destabilisation of the aortic wall. The reason for a higher MMP expression is rooted in a higher activity of TGF-β driven signalling pathways. One of the associated signalling cascades is the mTOR (mechanistic target of rapamycin) pathway. mTOR is a highly conserved protein which regulates central cell mechanisms as cell differentiation, cell proliferation and apoptosis. In addition, literature reviews suggest that there is a correlation between the expansion of inducible aortic aneurysms in animal models and the inhibition of mTOR via rapamycin.I was able to show in preliminary experiments that there is also a higher activity of mTOR in cryosections of the aortic wall of murine Marfan mice.Therefore, the working hypothesis of this project is that hereditary aortic diseases like Marfan syndrome are mTOR dependent. For a closer understanding of the underlying mechanisms several experiments are needed. First a rapamycin induced inhibition of mTOR in vitro in murine aortic smooth muscle cells (mAoSMC) from Marfan mice will be performed. This should provide the insight of whether the mTOR inhibition is capable of reducing the expression and activity of MMPs in the cell culture. After this proof of concept in vivo experiments will be carried out. The plan here is to inhibit elastolysis in the Marfan mouse and detect mechanistic changes in the aortic wall structure. In addition I aim to reduce or totally inhibit the expansion of aortic aneurysms for a survival benefit.Up till now the only therapy available for Marfan patients is the surgical correction of the expanding aortic aneurysms. No systemic therapy has so far lived up to its promises. In contrast rapamycin and other mTOR inhibitors have been already well established as imunmodulators in transplantation medicine. With a successful rapamycin-dependent inhibition of aortic aneurysm formation a systemic therapy could be optimized.

马凡综合征是一种复杂的遗传性疾病，由纤维蛋白-1基因突变引起的一系列症状。主要症状是血管紊乱、晶状体脱位和骨骼变形。主动脉瘤和夹层等危及生命的并发症目前还没有系统的治疗方法。这种疾病的血管成分的病理生理学可以解释为主动脉中膜中微纤维的不稳定。这种不稳定性是由于基质中的主动脉平滑肌细胞中基质金属蛋白酶的异常高表达和活性所致。这组酶降解弹性蛋白纤维，并通过微原纤维的碎裂导致更高的转化生长因子-β生物利用度。所有这些发现最终都会导致主动脉壁不稳定。基质金属蛋白酶高表达的原因是转化生长因子-β驱动的信号通路活性较高。其中一个相关的信号级联通路是mTOR(雷帕霉素的机械靶点)途径。MTOR是一种高度保守的蛋白质，它调节细胞分化、细胞增殖和细胞凋亡等中枢细胞机制。此外，文献综述表明，动物模型中可诱导的主动脉瘤扩张与雷帕霉素抑制mTOR之间存在相关性。我在初步实验中发现，在Marfan小鼠的主动脉壁冰冻切片中也存在较高的mTOR活性。因此，本项目的工作假设是，像Marfan综合征这样的遗传性主动脉疾病是mTOR依赖的。为了更好地了解潜在的机制，还需要几个实验。首先，我们将在体外进行雷帕霉素对马凡小鼠主动脉平滑肌细胞(MAoSMC)mTOR的抑制作用。这应该提供了关于mTOR抑制是否能够减少细胞培养中MMPs的表达和活性的洞察力。在此概念验证之后，将进行活体实验。这里的计划是抑制马凡小鼠的弹性溶解，并检测主动脉壁结构的机械变化。此外，我的目标是减少或完全抑制主动脉瘤的扩张，以获得生存利益。到目前为止，对马凡患者可用的唯一治疗方法是对扩张的主动脉瘤进行手术矫正。到目前为止，还没有一种系统性治疗方法兑现了它的承诺。相反，雷帕霉素和其他mTOR抑制剂已经在移植医学中被公认为免疫调节剂。随着雷帕霉素依赖抑制主动脉瘤形成的成功，系统治疗可能会被优化。