Chronic psychological stress potentiates IgE class switch recombination via glucocorticoid receptor-mediated epigenetic reprogramming of B cells.

BACKGROUND: Chronic psychological stress is a well-recognized factor in the exacerbation of allergic diseases, with IgE playing a central role in their pathophysiology. However, the exact molecular mechanisms by which stress hormones directly influence IgE production and contribute to allergic responses remain largely uncharacterized.
OBJECTIVE: This study aimed to elucidate the direct mechanisms through which chronic psychological stress, via elevated cortisol, regulates IgE class switch recombination (CSR) in B cells and contributes to stress-aggravated allergic inflammation in vivo.
METHODS: We employed a chronic restraint stress (CRS) mouse model to investigate the impact of psychological stress on humoral immunity. In vitro experiments utilized primary murine B cells treated with physiological cortisol concentrations (250 nM), incorporating molecular techniques such as CRISPR-Cas9-mediated gene knockdown, chromatin immunoprecipitation (ChIP), whole-genome bisulfite sequencing, and pharmacological inhibitors of epigenetic enzymes. Primary human B cells and the U266 human myeloma cell line were used for translational validation. In vivo validation was performed using an ovalbumin (OVA)-induced allergic airway inflammation model with B cell-specific glucocorticoid receptor (GR) knockout mice.
RESULTS: Chronic psychological stress significantly elevated plasma corticosterone and serum IgE levels in mice, with no changes in IgG1 or IgM. In purified in vitro B-cell cultures, cortisol promotes epigenetic remodeling at the Iε promoter region and enhances Iε germline transcript expression in an isotype-specific manner, and this effect was recapitulated in human B cells. GR bound to the Iε promoter's Amp_1 region (-154 to -62 bp), and CRISPR-Cas9-mediated GR knockdown abolished cortisol-induced IgE production. Mechanistically, cortisol increases enrichment of activating histone marks (H3K27ac, H3K4me3) and reduces H3K27me3 at the Iε promoter region, and induces site-specific DNA hypomethylation; inhibition of histone acetyltransferases (HATs) or DNA demethylation attenuated this effect. In vivo, B cell-specific GR knockout completely abrogated stress-induced exacerbation of allergic airway inflammation, including elevated serum IgE, eosinophilic inflammation, and airway hyperresponsiveness (AHR).
CONCLUSION: Our findings support a mechanistic model in which chronic psychological stress, through elevated glucocorticoids, acts via GR to promote epigenetic remodeling at the Iε promoter region in B cells to enhance IgE synthesis and exacerbate allergic responses. This study provides a critical molecular link between the neuroendocrine system and adaptive immunity, offering promising therapeutic targets for stress-aggravated IgE-mediated diseases.