| First Author | Taguchi K | Year | 2012 |
| Journal | Diabetes | Volume | 61 |
| Issue | 8 | Pages | 1978-85 |
| PubMed ID | 22688330 | Mgi Jnum | J:208537 |
| Mgi Id | MGI:5563656 | Doi | 10.2337/db11-1729 |
| Citation | Taguchi K, et al. (2012) G protein-coupled receptor kinase 2, with beta-arrestin 2, impairs insulin-induced Akt/endothelial nitric oxide synthase signaling in ob/ob mouse aorta. Diabetes 61(8):1978-85 |
| abstractText | In type 2 diabetes, impaired insulin-induced Akt/endothelial nitric oxide synthase (eNOS) signaling may decrease the vascular relaxation response. Previously, we reported that this response was negatively regulated by G protein-coupled receptor kinase 2 (GRK2). In this study, we investigated whether/how in aortas from ob/ob mice (a model of type 2 diabetes) GRK2 and beta-arrestin 2 might regulate insulin-induced signaling. Endothelium-dependent relaxation was measured in aortic strips. GRK2, beta-arrestin 2, and Akt/eNOS signaling pathway proteins and activities were mainly assayed by Western blotting. In ob/ob (vs. control [Lean]) aortas: 1) insulin-induced relaxation was reduced, and this deficit was prevented by GRK2 inhibitor, anti-GRK2 antibody, and an siRNA specifically targeting GRK2. The Lean aorta relaxation response was reduced to the ob/ob level by pretreatment with an siRNA targeting beta-arrestin 2. 2) Insulin-stimulated Akt and eNOS phosphorylations were decreased. 3) GRK2 expression in membranes was elevated, and, upon insulin stimulation, this expression was further increased, but beta-arrestin 2 was decreased. In ob/ob aortic membranes under insulin stimulation, the phosphorylations of Akt and eNOS were augmented by GRK2 inhibitor. In mouse aorta, GRK2 may be, upon translocation, a key negative regulator of insulin responsiveness and an important regulator of the beta-arrestin 2/Akt/eNOS signaling, which is implicated in diabetic endothelial dysfunction. |
