| Autor: |
Wu AD; Department of Anesthesiology, Vagelos College of Physicians and Surgeons, Columbia University, New York, New York., Dan W; Department of Anesthesiology, Vagelos College of Physicians and Surgeons, Columbia University, New York, New York., Zhang Y; Department of Anesthesiology, Vagelos College of Physicians and Surgeons, Columbia University, New York, New York., Vemaraju S; The Visual Systems Group, Abrahamson Pediatric Eye Institute.; Divisions of Pediatric Ophthalmology, Center for Chronobiology, and., Upton BA; The Visual Systems Group, Abrahamson Pediatric Eye Institute.; Divisions of Pediatric Ophthalmology, Center for Chronobiology, and.; Molecular and Developmental Biology Graduate Program.; Medical Scientist Training Program, and., Lang RA; The Visual Systems Group, Abrahamson Pediatric Eye Institute.; Divisions of Pediatric Ophthalmology, Center for Chronobiology, and.; Developmental Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio.; Department of Ophthalmology, University of Cincinnati, College of Medicine, Cincinnati, Ohio., Buhr ED; Department of Ophthalmology, University of Washington Medical School, Seattle, Washington; and., Berkowitz DE; Department of Anesthesiology, School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama., Gallos G; Department of Anesthesiology, Vagelos College of Physicians and Surgeons, Columbia University, New York, New York., Emala CW; Department of Anesthesiology, Vagelos College of Physicians and Surgeons, Columbia University, New York, New York., Yim PD; Department of Anesthesiology, Vagelos College of Physicians and Surgeons, Columbia University, New York, New York. |
| Abstrakt: |
Recently, we characterized blue light-mediated relaxation (photorelaxation) of airway smooth muscle (ASM) and implicated the involvement of opsin 3 (OPN3), an atypical opsin. In the present study, we characterized the cellular signaling mechanisms of photorelaxation. We confirmed the functional role of OPN3 in blue light photorelaxation using trachea from OPN3 null mice (maximal relaxation 52 ± 13% compared with wild-type mice 90 ± 4.3%, P < 0.05). We then demonstrated colocalization of OPN3 and G α s using co-IP and proximity ligation assays in primary human ASM cells, which was further supported by an increase in cAMP in mouse trachea treated with blue light compared with dark controls (23 ± 3.6 vs. 14 ± 2.6 pmol cAMP/ring, P < 0.05). Downstream PKA (protein kinase A) involvement was shown by inhibiting photorelaxation using Rp-cAMPS ( P < 0.0001). Moreover, we observed converging mechanisms of desensitization by chronic β 2 -agonist exposure in mouse trachea and correlated this finding with colocalization of OPN3 and GRK2 (G protein receptor kinase) in primary human ASM cells. Finally, an overexpression model of OPN1LW (a red light photoreceptor in the same opsin family) in human ASM cells showed an increase in intracellular cAMP levels following red light exposure compared with nontransfected cells (48 ± 13 vs. 13 ± 2.1 pmol cAMP/mg protein, P < 0.01), suggesting a conserved photorelaxation mechanism for wavelengths of light that are more tissue penetrant. Together, these results demonstrate that blue light photorelaxation in ASM is mediated by the OPN3 receptor interacting with G α s , which increases cAMP levels, activating PKA and modulated by GRK2. |
