The role of TFEB in aortic aneurysms

摘要 腹主动脉瘤（AAA）破裂后的死亡率非常高。到目前为止，除了外科手术外， 然而，由于只有10%的患者有资格接受干预，因此没有其他治疗方法可用。 因此，这将是非常重要的，以确定新的策略，以有效地治疗或预防腹主动脉瘤在体内。 血管平滑肌细胞（VSMC）在维持血管壁完整性和功能方面至关重要， 腹主动脉瘤中VSMC的稳态被破坏。转录因子-EB（TFEB）是溶酶体的“主”调节剂， 生物发生和自噬。然而，TFEB在VSMC功能和AAA形成中的作用仍有待进一步研究。 探讨了我们证明TFEB抑制VSMCs的凋亡、MMP 2/9活性和炎症。VSMC 特异性TFEB敲除（KO）显著地抑制了小鼠AAA模型中的血管壁基质降解。 脂肪酸的硝基烯烃衍生物如油酸（OA-NO2）和亚油酸（LNO 2）具有深刻的保护作用， 对心血管和代谢疾病的影响。共轭亚油酸（CLA）被鉴定为 优先和主要硝化的内源性脂肪酸，并且在人体和实验中易于生物利用 在口服CLA和无机亚硝酸盐（NO2）的模型，使其成为一个有吸引力的干预CVD。我们 发现硝基-CLA在血管紧张素II诱导的AAA小鼠模型中保护AAA的形成，并抑制 VSMC炎症和凋亡以TFEB依赖的方式。它还促进TFEB核转位 在体外以H148依赖的方式表明TFEB是硝基-CLA的直接靶标。基于这些 证据，我们将测试的中心假设，激活TFEB通过增强内源性生产 硝基-CLA通过抑制VSMC功能障碍来防止AAA的形成。通过利用 我们专门为这些研究生成的独特动物模型以及 团队合作，我们提出三个目标。目的1：研究VSMC TFEB对AAA形成的保护作用。 我们将测试我们的工作子假设，即VSMC TFEB通过抑制AAA形成来保护AAA。 VSMC功能障碍。目的2：确定硝基-CLA激活TFEB抑制体外VSMC功能障碍。 工作子假设是硝基-CLA以TFEB依赖性方式预防VSMC功能障碍。目的 3：将TFEB定义为用于体内AAA形成的硝基-CLA抑制的新型治疗靶标。工作分- 假设是内源性硝基-CLA的产生通过激活 VSMC TFEB。总之，我们将描述TFEB在AAA形成中的保护作用，并建立TFEB在AAA形成中的保护作用。 硝基-CLA是一种靶向VSMC TFEB治疗AAA的新策略。这种机械研究 将为硝基-CLA的快速转化为临床应用奠定坚实的基础，并可能导致 治疗或/和预防AAA的突破。

ABSTRACT Abdominal Aortic aneurysm (AAA) results in very high mortality upon rupture. To date, besides surgical intervention –with only 10% of patients eligible-, no alternative therapeutic approaches are available. Therefore, it would be of high significance to identify novel strategies to effectively treat or prevent AAA in vivo. Vascular smooth muscle cells (VSMCs) are crucial in maintaining vascular wall integrity and function and VSMC homeostasis is disrupted in AAA. Transcription factor-EB (TFEB) is a “master” regulator of lysosomal biogenesis and autophagy. However, the role of TFEB in VSMC functions and AAA formation remain to be explored. We demonstrated that TFEB inhibits apoptosis, MMP2/9 activity and inflammation in VSMCs. VSMC specific TFEB knockout (KO) significantly aggravates vascular wall matrix degradation in a mouse AAA model. Nitroalkene derivatives of fatty acids such as oleic (OA-NO2) and linoleic acid (LNO2) have profound protective effects against cardiovascular and metabolic diseases. Conjugated linoleic acid (CLA) was identified as the preferential and major nitrated endogenous fatty acid and is readily bioavailable in humans and experimental models upon oral delivery of CLA and inorganic nitrite (NO2), making it an attractive intervention for CVD. We found that nitro-CLA protects against AAA formation in the Ang II-induced AAA mouse model and inhibits VSMC inflammation and apoptosis in a TFEB-dependent manner. It also promotes TFEB nuclear translocation in vitro in an H148-dependent fashion suggesting that TFEB is a direct target of nitro-CLA. Based on these evidences, we will test the central hypothesis that activation of TFEB by enhancing the endogenous production of nitro-CLA protects against AAA formation through inhibition of VSMC dysfunction. By taking advantage of our unique animal models generated specifically for these studies and the combined expertise of the assembled team, we propose 3 aims. Aim 1: Characterize the protective role of VSMC TFEB in AAA formation. We will test our working sub-hypothesis that VSMC TFEB protects against AAA formation through inhibition of VSMC dysfunction. Aim 2: Determine that activation of TFEB by nitro-CLA inhibits VSMC dysfunction in vitro. The working sub-hypothesis is that nitro-CLA prevents VSMC dysfunction in a TFEB-dependent manner. Aim 3: Define TFEB as a novel therapeutic target for nitro-CLA inhibition of AAA formation in vivo. The working sub- hypothesis is that endogenous production of nitro-CLA protects against AAA formation through activation of VSMC TFEB. In summary, we will characterize the protective role of TFEB in AAA formation and establish nitro-CLA as a novel therapeutic strategy against AAA by targeting VSMC TFEB. This mechanistic research will set a solid foundation for rapid translation into clinical utilization of nitro-CLA and may lead to a breakthrough for treatment or/and prevention of AAA.