Khan Irfan, Ali Anwar, Akhter Muhammad Aleem, Naeem Nadia, Chotani Maqsood Ahmed, Iqbal Hana'a, Kabir Nurul, Atiq Mehnaz, Salim Asmat
Dr. Panjwani Center for Molecular Medicine and Drug Research, International Center for Chemical and Biological Sciences, University of Karachi, Karachi, Pakistan.
Center for Cardiovascular & Pulmonary Research, The Research Institute at Nationwide Children's Hospital, Columbus, OH, USA.
Cardiovasc Ther. 2017 Apr;35(2). doi: 10.1111/1755-5922.12248.
Rap1, a member of Ras superfamily of small GTP-binding proteins, is involved in cardiovascular biology in numerous ways. It is an evolutionary conserved regulator of adhesion, polarity, differentiation and growth.
Our aim was to analyze Rap1-activated rat bone marrow mesenchymal stem cells (MSCs) for their potential role in adhesion and cardiac differentiation.
Myocardial infarction (MI) was produced in Sprague Dawley (SD) rats through occlusion of the left anterior descending coronary artery. MSCs were treated with 8-pCPT-2'-O-Me-cAMP (CPT) to activate Rap1. Normal (untreated) and CPT-treated MSCs were transplanted through intramyocardial injection in respective groups. Cardiac function was assessed by echocardiography at 2 and 4 weeks after cell transplantation. Histological analysis was performed to observe changes at tissue level.
Homing of CPT-treated MSCs was significantly (***P<.001) higher as compared to normal MSCs in the infarcted hearts. This may be due to increase in the gene expression of some of the cell adhesion molecules as evident by qRT-PCR analysis. Significant (***P<.001) improvement in the restoration of heart function in terms of left ventricular diastolic and systolic internal diameters (LVIDd, LVIDs), % ejection fraction, % fraction shortening and end-systolic and end-diastolic volumes were observed in CPT-treated MSCs as compared to the MI model. Histological analyses showed significant (***P<.001) reduction in scar formation in the CPT-treated group. Differentiation of treated MSCs into functional cardiomyocytes was evident through immunohistochemical staining. LV wall thickness was also preserved significantly (***P<.001). Blood vessel formation was more pronounced in CPT-treated group although both cell therapy groups showed significant increase as compared to MI model.
Our findings showed that pharmacological activation of Epac-Rap1 improves cardiac function through better survival, adhesion and differentiation of transplanted cells. Transplantation of these MSCs in the infarct area restored functional myocardium.
Rap1是小GTP结合蛋白Ras超家族的成员之一，在心血管生物学中有着多种作用。它是一种在进化上保守的调节因子，参与细胞黏附、极性、分化和生长过程。
我们的目的是分析Rap1激活的大鼠骨髓间充质干细胞（MSCs）在黏附和心脏分化方面的潜在作用。
通过结扎左冠状动脉前降支在Sprague Dawley（SD）大鼠中制造心肌梗死（MI）。用8-pCPT-2'-O-Me-cAMP（CPT）处理MSCs以激活Rap1。将正常（未处理）和CPT处理的MSCs分别通过心肌内注射移植到相应组中。在细胞移植后2周和4周通过超声心动图评估心脏功能。进行组织学分析以观察组织水平的变化。
与正常MSCs相比，CPT处理的MSCs在梗死心脏中的归巢显著更高（***P<0.001）。这可能是由于一些细胞黏附分子的基因表达增加，qRT-PCR分析表明了这一点。与MI模型相比，在左心室舒张和收缩内径（LVIDd、LVIDs）、射血分数百分比、缩短分数百分比以及收缩末期和舒张末期容积方面，CPT处理的MSCs在心脏功能恢复方面有显著（***P<0.001）改善。组织学分析显示CPT处理组的瘢痕形成显著减少（***P<0.001）。通过免疫组织化学染色可明显看出处理后的MSCs分化为功能性心肌细胞。左心室壁厚度也得到显著保留（***P<0.001）。尽管与MI模型相比，两个细胞治疗组的血管形成均显著增加，但CPT处理组的血管形成更为明显。
我们的研究结果表明，Epac-Rap1的药理学激活通过改善移植细胞的存活、黏附和分化来改善心脏功能。将这些MSCs移植到梗死区域可恢复功能性心肌。
