Principal Investigator Columbia University New York, New York, United States
Abstract Text: Genome-wide association studies have identified members of the CARD11/MALT1/BCL10 (CBM) complex as susceptibility loci for allergic disorders. Loss of CBM complex function impairs lymphocyte receptor–mediated activation of NFκB as well as glutamine uptake—thereby selectively reducing signaling in mTORC1, but not mTORC2. Because patients with NFkB deficiency do not develop significant Th2 phenotypes, we therefore investigated how mTORC1/mTORC2 dysregulation might lead to Th2-associated allergic predisposition.
Using click chemistry with bio-orthogonal glutamine analogues, we observed reduced glutamine uptake upon T-cell receptor (TCR) stimulation in T cells from CARD11 patients, which was associated with reduced mTORC1 signaling, and preserved to elevated mTORC2 activation. Cultures of TCR-stimulated naïve CARD11DN CD4 T-cells lead to increased GATA3 expression compared to controls, which was inhibited via hyperphysiologic exogenous glutamine. Bulk RNA-seq of these cultures showed significant differences in expression of genes involved in PI3 kinase/AKT and autophagy pathways. Furthermore, 24 hours of glutamine deprivation in proliferating healthy control CD4⁺ T cells led to reduced mTORC1 signaling, NRF2-p62 pathway activation, increased Th2 cytokine production and mTORC2 signaling. Similarly, CARD11 mutant mice exhibited elevated nuclear NRF2 protein levels and p62 transcription compared to wild-type controls. Notably, NRF2 inhibitors suppressed the elevated Th2 cytokines in these mutant mice, mirroring our findings in human samples.
Decreased CBM function may promote Th2 phenotypes by impairing glutamine-mediated mTORC1 activation, while simultaneously enhancing mTORC2 and NRF2 activation. These results highlight a potentially fundamental immunometabolic pathway in Th2-mediated disease. Strategies to enhance intracellular glutamine or inhibit NRF2 and mTORC2 may prove therapeutic in such settings.
