FIG. 1.

Human coronary artery endothelial cell (HCAEC)–bound Jagged1 in a direct coculture of human coronary artery smooth muscle cells (HCASMCs) and HCAECs upregulates mRNA expression of Notch3 and modulates phenotypic marker genes in HCASMCs. HCASMCs were seeded on two-dimensional (2D) culture dishes and cultured for 4 days in smooth muscle growth media (SmGM) with or without soluble Jagged1 (A–C), or in SmGM supplemented with or without Jagged1-immobilized beads (D–F). Quantitative real-time polymerase chain reaction (PCR) analysis revealed that soluble Jagged1 has no effect on Notch3 transcriptional activity and smooth muscle cell (SMC) contractile marker genes. Conjugated Jagged1 beads were able to upregulate the expression of Notch3 but failed to upregulate SMC contractile marker genes. (G) HCAECs were transiently transfected with Jagged1 siRNA or scrambled siRNA (as a control) for 2 days prior to coculture with HCASMCs on 2D surfaces. Western blot analysis revealed that transfection was successful and the corresponding Jagged1 expression in HCAECs was significantly reduced. (H, I) Following 2 days of HCASMC and HCAEC coculture, quantitative real-time PCR analysis revealed that direct coculture of HCASMCs and HCAECs significantly downregulates when Jagged1 was knocked down in HCAECs using siRNA. Data are represented as mean±standard deviation (SD) from three independent experiments (*p<0.05).