| First Author | Morris GE | Year | 2022 |
| Journal | Br J Pharmacol | Volume | 179 |
| Issue | 21 | Pages | 4958-4973 |
| PubMed ID | 35802072 | Mgi Jnum | J:333698 |
| Mgi Id | MGI:7438014 | Doi | 10.1111/bph.15921 |
| Citation | Morris GE, et al. (2022) The integrin ligand SVEP1 regulates GPCR-mediated vasoconstriction via integrins alpha9beta1 and alpha4beta1. Br J Pharmacol 179(21):4958-4973 |
| abstractText | BACKGROUND AND PURPOSE: Vascular tone is regulated by the relative contractile state of vascular smooth muscle cells (VSMCs). Several integrins directly modulate VSMC contraction by regulating calcium influx through L-type voltage-gated Ca(2+) channels (VGCCs). Genetic variants in ITGA9, which encodes the alpha9 subunit of integrin alpha9beta1, and SVEP1, a ligand for integrin alpha9beta1, associate with elevated blood pressure; however, neither SVEP1 nor integrin alpha9beta1 has reported roles in vasoregulation. We determined whether SVEP1 and integrin alpha9beta1 can regulate VSMC contraction. EXPERIMENTAL APPROACH: SVEP1 and integrin binding were confirmed by immunoprecipitation and cell binding assays. Human induced pluripotent stem cell-derived VSMCs were used in in vitro [Ca(2+) ](i) studies, and aortas from a Svep1(+/-) knockout mouse model were used in wire myography to measure vessel contraction. KEY RESULTS: We confirmed the ligation of SVEP1 to integrin alpha9beta1 and additionally found SVEP1 to directly bind to integrin alpha4beta1. Inhibition of SVEP1, integrin alpha4beta1 or alpha9beta1 significantly enhanced [Ca(2+) ](i) levels in isolated VSMCs to Galpha(q/11) -vasoconstrictors. This response was confirmed in whole vessels where a greater contraction to U46619 was seen in vessels from Svep1(+/-) mice compared to littermate controls or when integrin alpha4beta1 or alpha9beta1 was inhibited. Inhibition studies suggested that this effect was mediated via VGCCs, PKC and Rho A/Rho kinase dependent mechanisms. CONCLUSIONS AND IMPLICATIONS: Our studies reveal a novel role for SVEP1 and the integrins alpha4beta1 and alpha9beta1 in reducing VSMC contractility. This could provide an explanation for the genetic associations with blood pressure risk at the SVEP1 and ITGA9 loci. |
