血管生成因子AGGF1调节高血压心肌重构的作用及机制研究

Recent findings have demonstrated that angiogenesis and inflammation are closely related to the occurrence and development of hypertensive cardiac remodeling. AGGF1 is an important angiogenic factor and novel anti-inflammatory factor. Our preliminary study found that WT mice were given Ang II about 2w, the microvascular density was significantly reduced, the inflammatory cells, the area of cardiomyocyte, the apoptosis and fiber deposition of myocardium were markedly increased as compared with sham control. The results were contrary after recombinant AGGF1 was given. Accordingly, we think AGGF1 possiblely regulate the development of myocardial remodeling by enhancing angiogenesis, inhibiting inflammation, hypertrophy, apoptosis and fibrosis of myocardium. In the present study, using the culture systems of cardiac microvascular endothelial cells and cardiomyocytes, using WT mice treated with Ang II and recombinant AGGF1 or AGGF1 neutralization antibody, we study the impact of AGGF1 on the myocardial angiogenesis, inflammation, hypertrophy, apoptosis and fibrosis, and clarify the pathological mechanism that the AGGF1 regulated the development of hypertensive cardiac remodeling, and suggest that it may be a potential target for the early prevention and treatment of hypertensive cardiac remodeling.

高血压心肌重构的发生发展与血管新生及炎症密切相关。AGGF1不仅具有重要的促血管生成作用，也是一种新的抗炎因子。我们前期实验发现，血管紧张素Ⅱ（AngⅡ）刺激野生（WT）小鼠2周后，给予AGGF1重组蛋白可显著增加心肌微血管密度，减少炎细胞浸润，减小心肌细胞面积，降低心肌细胞凋亡及纤维沉积，提示AGGF1可能通过促进血管新生，减轻炎症反应，抑制心肌肥大、心肌凋亡和纤维化，调节高血压心肌重构的发生发展。本课题拟通过给予AGGF1重组蛋白或中和抗体，在AngⅡ刺激体外培养的心肌微血管内皮细胞、心肌细胞以及AngⅡ诱导小鼠心肌重构模型中，阐明AGGF1对血管新生、炎症反应、心肌肥大、心肌凋亡及纤维化的作用，明确AGGF1参与心肌重构的信号通路的变化，从而为深入阐明高血压心肌重构的发病机制及寻找新的治疗靶点提供实验依据。

持续的心肌重构是心力衰竭发生发展的主要原因，因此寻找改善心肌重构新的治疗靶点尤其重要。AGGF1不仅参与血管新生、个体发育等过程，还与炎症反应密切相关。本课题采用苯肾上腺素（PE）刺激心肌细胞，升主动脉缩窄术（TAC）诱导心肌肥厚及心力衰竭模型，检测AGGF1mRNA和蛋白表达水平。应用AGGF1过表达腺病毒或干扰腺病毒预处理心肌细胞，再给予PE刺激，免疫荧光检测心肌细胞面积, RT-PCR检测心肌细胞ANF、BNP和β-MHC的表达水平，明确AGGF1对心肌细胞肥大的影响。尾静脉注射AGGF1过表达腺相关病毒后，制备TAC2周和TAC11周模型，超声检测小鼠心脏功能；计算心脏重量/体重和心脏重量/胫骨长度比率；HE染色观察心脏组织形态学改变；免疫组化染色检测心肌巨噬细胞浸润情况；麦胚凝集素(WGA)染色检测心肌细胞面积；天狼星红染色观察心脏纤维化改变情况；Western Blot检测TGF-β1、Smad2/3、α-SMA蛋白的表达水平。研究结果发现术后11周，与Sham组相比，TAC组小鼠心功能明显降低；心脏重量/体重和心脏重量/胫骨长度比率明显增高；心肌细胞横截面积显著增大；心肌间质炎性细胞及巨噬细胞增加；心肌纤维化面积增加；TGF-β1、Smad2/3、α-SMA蛋白表达水平明显增高，而过表达AGGF1组心肌肥大、炎症及心肌纤维化程度则明显减低。提示AGGF1通过参与心肌肥大、炎症反应及 TGF-β/Smad2/3信号介导的心肌纤维化促进高血压心肌重构的发生发展。本课题为深入研究高血压心肌重构致病机制提供了实验依据，为临床研究高血压心肌重构新的药物靶点提供一些思路和线索。