Unfolded Protein Response Factor ATF6 Augments T Helper Cell Responses and Promotes Mixed Granulocytic Airway Inflammation

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Abstract The unfolded protein response (UPR) plays a critical role in many diseases, including airway inflammation. Several recent studies demonstrated a pathogenic role of Activating transcription factor 6a (ATF6a or ATF6), one of the essential arms of UPR, in airway structural cells. However, its role in T helper (TH) cells has not been well examined. In this study, we found that ATF6 was selectively induced by STAT6 and STAT3 in TH2 and TH17 cells, respectively. ATF6 upregulated UPR genes and promoted the differentiation and cytokine production of TH2 and TH17 cells. T cell-specific Atf6-deficiency impaired TH2 and TH17 responses in vitro and in vivo and attenuated mixed granulocytic experimental asthma. ATF6 inhibitor Ceapin A7 suppressed ATF6 downstream gene expression and TH cell cytokine expression in both murine and human memory CD4 +T cells. Administration of Ceapin A7 lessened both TH2 and TH17 responses in vivo, leading to alleviation of both airway neutrophilia and eosinophilia. Thus, our results demonstrate a novel role of ATF6 in TH2 and TH17 cell-driven mixed granulocytic airway disease, suggesting a novel option to combat steroid-resistant mixed and even T2-low endotypes of asthma through targeting ATF6. This work was supported in part by NIH grants HL148337 and AI142200 (X.O.Y.), and DK110439 and DK132643 (M.L.). We acknowledge the University of New Mexico Comprehensive Cancer Center Flow Cytometry Core supported by NIH CA118100 and the Autophagy, Inflammation, and Metabolism in Disease Center Inflammation and Metabolism Core supported by NIH GM121176