Protective Role of ?-arrestin2 in Colitis Through Modulation of T-cell Activation.
ABSTRACT: ?-arrestin2 (?-arr2), identified as a scaffolding protein in G-protein-coupled receptor desensitization, is a negative regulator of inflammation in polymicrobial sepsis. In this study, we wanted to investigate the role of ?-arr2 in intestinal inflammation, a site of persistent microbial stimulation. In the absence of ?-arr2, mice exhibited greater extent of mucosal inflammation determined by cellular infiltration and expression of inflammatory mediators even under homeostatic conditions. Furthermore, ?-arr2-deficient mice were more susceptible to dextran sulfate sodium-induced colitis as demonstrated by greater body weight loss, higher disease activity index, and shortened colon as compared with wild-type mice. We also show that T cells from ?-arr2 knockout mice exhibit altered activation status under both basal and colitic conditions, implicating their involvement in disease induction. Further assessment of the role of ?-arr2 in intrinsic T-cell differentiation confirmed its importance in T-cell polarization. Using the T-cell transfer model of colitis, we demonstrate that T-cell-specific ?-arr2 is important in limiting colitic inflammation; however, it plays a paradoxical role in concurrent systemic wasting disease. Together, our study highlights a critical negative regulatory role of ?-arr2 in intestinal inflammation and demonstrates a distinct role of T-cell-specific ?-arr2 in systemic wasting disease.
PROVIDER: S-EPMC4654649 | BioStudies |