Patient-Specific Induced Pluripotent stem cell models of variant angina derived from peripheral blood

Abstract

Cardiovascular disease is the one of the most common causes of death in the world. Specially, variant angina is more prevalent in Korean and Japanese than in Caucasian population. Variant angina is caused by a spasm in the coronary arteries and is considered a fatal disease, since it leads to myocardial infarction, arrhythmia, and sudden death. Until now, however, the mechanisms of this illness have not been elucidated. I isolated circulating multipotent stem (CiMS) cells from normal and variant angina patient peripheral blood to generate human induced pluripotent stem cells (hiPSC). Human vascular smooth muscle cells (VSMCs) were differentiated from hiPSC and their calcium efflux was analyzed using with the fluorescent dye FLUO4. Moreover, endothelial cells (EC) were differentiated from hiPSC and characterized with immunocytochemistry and observed immunofluorescent using confocal microscopy. Using the calcium efflux model, I observed a high intensity of intracellular calcium and specific calcium efflux in the variant angina group, but not in the normal group. I identified differences between normal and variant angina vascular smooth muscle cells contractility using an in vitro calcium fluorescence model. Increased expression of Serca2 was also observed in variant angina VSMCs. I also confirmed increased Serca2 protein expression and its SUMOylation, which is the key factor to regulate VSMC hyperactivity. I isolated CiMS from normal and variant angina patients and observed hyperactivity in samples from variant angina patients and overepxression of Serca2 as well as an increase in sumoylated Serca2, which might be a mechanism underlying the cause of artery spasms. These newly identified mechanisms of variant angina showed clinical relevance, suggesting that these mechanisms could be promising for the development of new drugs and effective therapy.