A method for in vitropolarization of pathogenic ST2-expressing memory Th2 cells

Abstract

Abstract IL-33 and its receptor subunit ST2 (IL1RL1) have been linked to type 2 eosinophilic asthma in multiple human and mouse studies. In particular, recent clinical trials demonstrate that monoclonal antibodies targeting IL-33/ST2 are beneficial to subsets of asthma patients. ST2 +memory Th2 cells (mTh2) are important effector cells in IL-33-mediated type 2 eosinophilic asthma. Herein we describe a unique method for polarizing a subset of pathogenic ST2 +mTh2 (ST2 +mTh2p) cells from naïve mouse CD4 T cells in vitro, which does not require multi-round activation/resting or co-culturing with antigen-presenting cells as reported in prior studies. The ST2 +mTh2p cells proliferate and produce large amounts of type 2 cytokines upon IL-33 treatment [without involving T-cell receptor (TCR) ligation]. IL-33 stimulation induces metabolic reprogramming of ST2 +mTh2p, as indicated by the increased mitochondrial respiration and glycolytic rate in Seahorse assays as well as upregulated key metabolites and metabolic genes involved in these two bioenergetic pathways. Interestingly, IL-33 stimulation also increases the metabolites and the expression of key enzymes for the production of polyamines (the important regulators of cell proliferation). Moreover, ST2 +mTh2p cells are highly pathogenic, as they are capable of propagating and producing type 2 cytokines in the lung, resulting in strong eosinophilic inflammation induced by intranasal IL-33 administration alone after adoptive transfer to Rag2−/−IL2r−/−mice (lacking both innate and adaptive lymphocytes). In summary, the current study provides useful tools to investigate IL-33/ST2-regulated molecular mechanisms and immunological functions of ST2 +mTh2p cells both in vitroand in vivo. R0 1HL144497