Introduction:G protein-coupled receptor 35 (GPR35) is a poorly characterized receptor with controversial endogenous ligands and unclear intracellular signaling pathways. Links between GPR35 and hypertension have been suggested in recent studies. It has been reported that GPR35 knockout mice showed resistance to the development of hypertension induced by angiotensin II but the mechanism was unclear. We hypothesized that deletion of GPR35 protects blood pressure through augmenting endothelial cell function.Methods and Results:Human aortic endothelial cells (HAECs) at passage 5-7 were cultured in vitro. Real-time PCRs confirmed descent expression levels of GPR35 in HAECs. Knocking-down of GPR35 in HAECs by adenovirus carrying shRNA against GPR35 improved cell functions including angiogenesis (3D tube formation in collagen culture) and migration (modified Boyden Chamber assay) (n=6, p<0.05 vs. control). Mouse aortic endothelial cells (MAECs) were isolated from adult male GPR35 global knockout (GPR35null) mice and their age- and gender-matched wild type control (GPR35WT) litters. GPR35nullMAECs showed improved angiogenesis, migration and proliferation compared with GPR35WTMAECs (n=5, p<0.05), with enhanced eNOS protein expression and phosphorylation (p-eNOS) (Western Blot, n=5, p<0.05). In the in vivostudy, GPR35nullmice had 22 mmHg of decrease in mean blood pressure (MBP) compared to GPR35WTmice as measured by implanted telemetry (n=2-3, p<0.05 vs. GPR35WT). The plasma levels of angiotensin II were comparable between GPR35nulland GPR35WTmice (n=6-10, p>0.05). In a deoxycorticosterone acetate (DOCA)-salt induced hypertensive mouse model, GPR35 deletion lowered MBP by 11 mmHg as measured by tail-cuff method (n= 5-6, p <0.05 vs. DOCA-GPR35WT).Conclusions:Our data suggest that deletion of GPR35 can prevent blood pressure elevation induced by DOCA-Salt model in mice, possibly through improving endothelial cell function. This is related to the enhanced angiogenesis through higher expression of eNOS and its activated phosphorylated form in endothelial cells. This study has provided novel evidence for the therapeutic potential of GPR35 in anti-hypertensive treatments.