基因修饰的脂肪干细胞对肺动脉高压大鼠肺动脉结构与功能的影响及机制

Pulmonary arterial remodelling is the key cause of the persistent increase of pulmonary arterial pressure．Our previous study showed that transplanted adipose tissue-derived mesenchymal stem cells (ADMSCs) could colonize and differentiate into endothelial-like cells in the pulmonary arteries of pulmonary hypertensive rats. Pulmonary hypertension and arteriolar remodeling induced by monocrotaline in rats could be significantly attenuated by the treatment with ADMSCs. In addition, we also found in the previous study that the transplantation of human adiponectin (HapM1) gene-modified ADMSCs survived in the area of infarcted myocardium and differentiate into myocardial cells and express the cardiac troponin I (CTNI) in rats with myocardial infarction. Cardiac function was markedly improved and tissue injury was significantly ameliorated by the treatment with HapM1 gene-modified ADMSCs in myocardial infarction rats. Based on the above findings, we propose a hypothesis that the transplantation of gene-modified ADMSCs may constantly synthesize some bioactive factors in vivo, which could reduce pulmonary arterial hypertension and regress pulmonary arterial remodeling. This study aims to determine the effects of the transplantation of ADMSCs and gene-modified ADMSCs on:① pulmonary arterial hypertension, pulmonary arterial remodeling and function; ② the expression of calcium channel on pulmonary arterial smooth muscle cells (PASMCs) ; ③ the expression of bone morphogenetic proteins Ⅱ receptor (BMPR-Ⅱ) in PASMCs in monocrotaline-induced PAH rats, hoping that the experiment will shed light on the role and mechanism of ADMSCs and gene-modified ADMSCs in the treatment of pulmonary hypertension.

肺动脉高压时，肺血管重构是导致肺动脉压力持续增高的主要原因。本课题组的前期研究发现脂肪干细胞能够在大鼠肺动脉定植并分化为内皮样细胞，同时能够显著降低野百合碱诱发的肺动脉高压大鼠的肺动脉压力，改善肺动脉重构。本课题组在其它研究中发现经过人脂联素基因修饰的脂肪干细胞移植到心肌梗死大鼠，可在心肌损伤部位存活，并分化表达心肌细胞标志物，能够更好地改善心脏功能和促进组织修复。因此，我们提出假设，经过基因修饰的脂肪干细胞移植治疗肺动脉高压，可能可以在体内不断合成具有降低肺动脉压力和改善肺动脉重建的生物活性因子。本课题重点研究对比脂肪干细胞和经基因修饰的脂肪干细胞移植于肺动脉高压大鼠对：①肺动脉高压、肺动脉重塑和功能的影响；②肺动脉平滑肌细胞钙离子调节相关通道表达的影响；③肺动脉平滑肌细胞骨形成蛋白受体Ⅱ表达的影响，旨在探寻经基因修饰的脂肪干细胞在肺动脉高压治疗中的作用和机制。

本项目围绕脂肪干细胞( adipose tissue-derived stem cell,ADSC)及脂联素(adiponectin，APN)修饰的脂肪干细胞(APN-ADSC)在肺动脉高压(pulmonary arterial hypertension,PAH)治疗中的作用及其机制进行了深入的研究。我们取得了以下关键研究结果：① 明确了ADSC可定植于PAH大鼠的肺血管内，并分化为内皮样细胞，降低肺动脉压，改善肺血管重构；②APN-ADSC能够定植于肺血管内，并降低野百合碱诱导的的PAH大鼠的肺动脉压、改善肺血管重构以及肺动脉内皮依赖性和非内皮依赖性的舒张功能，其治疗效果优于单纯的ADSC；③APN-ADSC治疗可以改善野百合碱诱导的PAH大鼠的Warburg效应和丙氨酸代谢异常，单纯的ADSC治疗对PAH大鼠的代谢模式改变并不明显，这可能是APN-ADSC治疗PAH效果优于ADSC的重要机制之一；④APN能抑制肺动脉平滑肌细胞增殖，与其上调BMP2的表达，激活Smad1/5/8和AMPK有关，BMP和AMPK抑制剂可抑制APN诱导的BMP/Smad和AMPK信号通路的激活。通过本项目的研究我们确定APN-ADSC移植是更好的治疗PAH的方法，并可能为该疾病治疗提供新的方法和分子靶点。