ITGα4β1/VCAM-1调控iPSC治疗PM2.5诱发肺损伤的作用及机制研究

PM2.5是诱发和加重肺损伤（LI）的主要危险因素之一，肺纤维化（PF）是大多LI的终末期病变，致死率高，尚缺有效治疗手段。申请人证实整合素α4β1/血管细胞黏附分子（VCAM-1）介导中性粒细胞（PMN）浸润是PM2.5诱发LI的关键；诱导性多能干细胞（iPSC）可通过抗炎等途径缓解LI，但机制仍不明确。其靶向归巢对治疗很关键。课题组发现iPSC中整合素α4β1敲除显著抑制iPSC向LI部位归巢。由此假设整合素α4β1/VCAM-1调控iPSC靶向竞争性抑制PMN组织浸润治疗PM2.5诱发的LI。拟通过PM2.5诱发LI，结合外周血PMN去除和回输，利用CRISPR-Cas9、微流控芯片等技术，从小鼠组织、细胞和分子层面①明确整合素α4β1/VCAM-1调控iPSC治疗PM2.5诱发LI的作用，②探究其通过靶向竞争性抑制PMN组织浸润的潜在机制，以期为iPSC早期高效治疗PF提供新手段。

Fine ambient particle matter (PM2.5) do great harm to human body, it enters body through respiratory system, directly affect lungs, and it is one of the main risk factors for lung diseases such as PF. Pulmonary fibrosis (PF) is a progressive and fatal fibrosing interstitial lung disease of unknown etiology, while there is currently no effective treatment available. We have previously confirmed that integrin α4β1 (ITG α4β1)/vascular cell adhesion molecule-1 (VCAM-1) -mediated neutrophil infiltration is one of the key events of PM2.5 induced lung injury; Intravascularly administered with syngeneic mouse induced pluripotent stem cells (iPSC) can effectively inhibit PMN infiltration and ameliorate lung injury in mice. However, iPSC therapy has been hindered by a key problem, lack of targeting or poor cell engraftment, resulting in poor therapeutic effects thereby hampering extensive application of this technology in clinical. In our preliminary experiments, we using gene editing technology Crispr-Cas9 to knockout the expression of ITG α4β1 subunits in iPSC can significantly reduce the adhesion and homing of iPSC to injured tissues. Therefore, we hypothesize that ITG α4β1/VCAM-1 regulates iPSC to repair PM2.5-induced progressive lung injury by competitively inhibiting PMN infiltration. We will establish the injured models of mice and pulmonary microvascular endothelial cells by PM2.5 inducing, and combine the experimental techniques of the peripheral blood neutrophil depletion and reinfusion, Crispr-Cas9, microfluid chip model and so on, to investigate the potential roles and molecular mechanisms of ITG α4β1/VCAM-1 regulated iPSC on PM2.5-induced progressive lung injury by competitively inhibiting PMN infiltration. The project will have significant contribution to provide a new insight for improving the therapeutic effect of iPSC on PF caused by environmental pollution such as PM2.5.