Regulator of G-protein signaling 1 critically supports CD8⁺ T_RM cell-mediated intestinal immunity

Members of the Regulator of G-protein signaling (Rgs) family regulate the extent and timing of G protein signaling by increasing the GTPase activity of G alpha protein subunits. The Rgs family member Rgs1 is one of the most up-regulated genes in tissue-resident memory (T-RM) T cells when compared to their circulating T cell counterparts. Functionally, Rgs1 preferentially deactivates G alpha q, and G alpha i protein subunits and can therefore also attenuate chemokine receptor-mediated immune cell trafficking. The impact of Rgs1 expression on tissue-resident T cell generation, their maintenance, and the immunosurveillance of barrier tissues, however, is only incompletely understood. Here we report that Rgs1 expression is readily induced in naive OT-I T cells in vivo following intestinal infection with Listeria monocytogenes-OVA. In bone marrow chimeras, Rgs1(-/-) and Rgs1(+/+) T cells were generally present in comparable frequencies in distinct T cell subsets of the intestinal mucosa, mesenteric lymph nodes, and spleen. After intestinal infection with Listeria monocytogenes-OVA, however, OT-I Rgs1(+/+) T cells outnumbered the co-transferred OT-I Rgs1(-) (/-) T cells in the small intestinal mucosa already early after infection. The underrepresentation of the OT-I Rgs1(-/-) T cells persisted to become even more pronounced during the memory phase (d30 post-infection). Remarkably, upon intestinal reinfection, mice with intestinal OT-I Rgs1(+/+) T-RM cells were able to prevent the systemic dissemination of the pathogen more efficiently than those with OT-I Rgs1(-/-) T-RM cells. While the underlying mechanisms are not fully elucidated yet, these data thus identify Rgs1 as a critical regulator for the generation and maintenance of tissue-resident CD8(+) T cells as a prerequisite for efficient local immunosurveillance in barrier tissues in case of reinfections with potential pathogens.