Coordinated transcriptional and epigenetic regulation of type 2 CD8+ T cells in asthma

Rational Steroid-insensitive type 2 cytokine-producing CD8 + T cells (Tc2) are enriched in patients with severe asthma and correlate with disease severity, highlighting their potential role as drivers of treatment-refractory disease. The molecular mechanisms governing their functional differentiation remain incompletely understood. Methods Mouse CD8 + T cells were differentiated in vitro under type 1 or type 2 polarizing conditions. Genome-wide transcriptional and H3 histone acetylation profiles were analyzed using RNA sequencing and chromatin immunoprecipitation (ChIP) sequencing. Both were integrated to identify H3Ac-associated transcriptional programs. Functional consequences of pharmacologic inhibition of histone acetyltransferase (HAT) activity in Tc2 cells were assessed after adoptive transfer into allergen-sensitized CD8-deficient mice. In parallel, transcriptomic profiling of human CD8 + T cells from healthy individuals and steroid-resistant asthmatics was performed and integrated with the mouse Tc2 dataset to identify conserved regulatory pathways. Results Tc1 and Tc2 differentiation were characterized by coordinated transcriptional remodeling with distinct type 2-associated networks emerging in response to IL-4 and T cell receptor stimulation including Il-24 , Cyp11a1 , and Il-13 . Integration of histone acetylation data and transcriptional networks identified condition-specific H3Ac-associated differentially-expressed genes (DEGs) and functional programs specific to Tc1 and Tc2 cells. While H3Ac-associated DEGs in Tc1 cells were linked predominantly to broader inflammatory and immune effector pathways, this integrative approach showed an enrichment of type 2 immune pathways in Tc2 cells. Pharmacologic modulation of HAT activity increased Tc2 cytokine responses and enhanced the pathogenic effects of Tc2 cells in vivo , resulting in heightened airway hyperresponsiveness and eosinophilic inflammation. Human CD8 + T cells from steroid-resistant asthmatics exhibited distinct transcriptional profiles compared with healthy individuals, including increased IL-13 expression. Cross-species integration revealed significant overlap between mouse Tc2 transcriptional signatures and gene networks in steroid-resistant asthmatics. Conclusion These findings propose coordinated epigenetic and transcriptional remodeling as a central mechanism regulating functional differentiation of Tc2 cells. They further define shared molecular pathways linking CD8 + T cell programming to type 2 inflammation in severe asthma, providing insight into mechanisms that may contribute to persistent disease and therapeutic resistance.