ABSTRACT: As the critical step of pathogenesis during hypoxic pulmonary arterial hypertension (PAH) vascular remodeling is closely associated with pulmonary arterial smooth muscle cell (PASMC) alterations induced by hypoxia that include persistent vasoconstriction, abnormal proliferation and PASMC resistance to apoptosis. Quercetin is a flavonoid compound extracted from green plants that inhibits proliferation, induces apoptosis, arrests the cell cycle, and rescues the constriction of PASMCs, but the underlying mechanisms remain poorly understood. In this study, we used a commercial Agilent Whole Rat Genome Oligo Microarray to determine the overall transcriptional response of PASMCs in response to exposure to hypoxia and the optimal concentration of quercetin. Hypoxia induced the upregulation of 1694 genes and the downregulation of 2091 genes compared with the normoxia group. Quercetin treatment resulted in 1790 upregulated genes and 1450 downregulated genes. Quercetin is known to cause differential expression of several of these genes that are known to promote proliferation, induce apoptosis (Cycs, Ppp3ca, Prkar2b, Akt3, Ppp3cc, Il1rap, Ntrk1), arrest the cell cycle (Chek2, Cdkn1c, Gadd45b, Stag2, Anapc7, Orc1, Ccne1, Myc3, Skp1, Espl1, Cdc45, Mcm4), and rescue PASMC constriction (Ramp1, Ramp3, Adcy5, Gnas, Prkcd, Itpr3, Adra1d, Calm1, Npr1, Avpr1a, Ednra, Adcy8). Real-time quantitative RT-PCR was performed to verify the microarray results. In conclusion, quercetin altered the expression profile of many genes regulated by hypoxia in PASMCs, which helps to further explore the mechanism of the effects of quercetin treatment on hypoxic PAH.
