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Previously, we have succeeded in inducing and isolating vascular endothelial cells (ECs) and mural cells (MCs) from human iPS cells. Recently, we modified our vascular differentiation system and we have induced vascular cells more effectively and stably from various ES/iPS cell clones. Our vascular differentiation system could be applied for the clarification of vascular biology or pathology, because we can observe the change of gene expressions in the process of human vascular cell differentiation, not mouse or other species.We have researched about the expressions of cardiovascular hormones and their receptors through our vascular differentiation kinetics, aiming to research the meanings of these hormones into vascular cells. At first, we examined mRNA expressions in undifferentiated ES/iPS cells, ES/iPS-derived immature vascular cells, ES/iPS-derived ECs, ES/iPS-derived MCs. Also we used cell line aortic ECs and smooth muscle cells(SMCs) as control.hES/iPS derived ECs expressed adrenomedullin and endothelin, which mean that we succeed to induce mature ECs endocrinologically. Also I examined the expressions of natriuretic peptides family. Interestingly, the mRNA expression of brain natriuretic peptide (BNP) was highly detected only in sorted Flk1-positive cells, which are considered as immature vascular cells. After differentiation, these BNP expressions were decreased. Also we could measure BNP at high concentration in the culture medium of Flk1 positive cells. By doing fraction assay, the majority of measured BNP turned out to be not BNP-32 but pro-BNP. As for NP receptors, GC-A were expressed only in ES or iPS – derived EC.These results suggest the possibility that BNP (which would be secreted from immature vascular cells) has some paracrine functions to vascular endothelial cells and now we examine the function of BNP for vascular differentiation/development. Also I would introduce other application of our vascular differentiation system, using patient specific-iPS cells.