Lensing, M. | bioRxiv Science

bioRxiv2025

Th1 effector CD4 T cells rely on IFN-γ production to induce alopecia areata

Alopecia areata (AA) is an autoimmune disease that is clinically characterized by hair loss and histologically by a peribulbar infiltrate of CD8 and CD4 T cells. Prior studies have focused on the role of CD8 T cells in the development of AA; however, the role of CD4 T cells remains unclear. Here, we demonstrate that CD4 T cells from the skin draining lymph nodes (SDLN) of AA mice transferred disease into recipient mice. Further, these cells exhibited a T-helper type 1 (Th1) effector transcriptional and phenotypic profile. The pathogenic activity of these CD4 T cells was dependent upon the presence of endogenous CD8 T cells and host IFN-{gamma} responsiveness. Targeted deletion of CD4 T cell-mediated production of IFN-{gamma} abrogated the ability of this cell population to transfer disease. Together, these data provide mechanistic insights into pathways that lead to AA development, strengthening our understanding of the disease and inviting studies into exploring novel therapeutic strategies for human patients.

immunology↗

bioRxiv2021

Targeting Gi/o protein-coupled receptor signaling blocks HER2-induced breast cancer development and enhances HER2-targeted therapy

G protein coupled receptors (GPCRs) are among the most desirable drug targets for human disease. Although GPCR dysfunction drives the development and progression of many tumors including breast cancer (BC), targeting individual GPCRs has limited efficacy as a cancer therapy because numerous GPCRs are activated. In this study, we sought a new way of blocking GPCR activation in HER2+-BC by targeting a subgroup of GPCRs that couple to Gi/o proteins (Gi/o-GPCRs). Using cell lines and transgenic mouse models, we showed in mammary epithelial cells, HER2 hyperactivation altered GPCR expression, particularly, Gi/o-GPCRs. Gi/o-GPCR stimulation transactivated EGFR and HER2, which in turn activated the PI3K/AKT and Src pathways. Uncoupling Gi/o-GPCRs from cognate Gi/o proteins by pertussis toxin (PTx) inhibited BC cell proliferation and migration in vitro and suppressed HER2-driven tumor formation and metastasis in vivo. Moreover, targeting Gi/o-GPCR signaling via PTx, PI3K, or Src inhibitors enhanced HER2-targeted therapy. These results indicate that HER2 hyperactivation in BC cells drives aberrant Gi/o-GPCR signaling, and Gi/o-GPCR signals converge on PI3K/AKT and Src signaling pathways to promote cancer progression and the development of resistance to HER2-targeted therapy. Our findings suggest a new way to pharmacologically deactivate GPCR signaling to block tumor growth and enhance therapeutic efficacy.

cancer biology↗