Search

Background: Mast cell-derived mediators induce vasodilatation and fluid extravasation, leading to cardiovascular failure in severe anaphylaxis. We previously revealed a synergistic interaction between the cytokine IL-4 and the mast cell-derived mediator histamine in modulating vascular endothelial (VE) dysfunction and severe anaphylaxis. The mechanism by which IL-4 exacerbates histamine-induced VE dysfunction and severe anaphylaxis is unknown., Objective: We sought to identify the IL-4-induced molecular processes regulating the amplification of histamine-induced VE barrier dysfunction and the severity of IgE-mediated anaphylactic reactions., Methods: RNA sequencing, Western blot, Ca 2+ imaging, and barrier functional analyses were performed on the VE cell line (EA.hy926). Pharmacologic degraders (selective proteolysis-targeting chimera) and genetic (lentiviral short hairpin RNA) inhibitors were used to determine the roles of signal transducer and activator of transcription 3 (STAT3) and STAT6 in conjunction with in vivo model systems of histamine-induced hypovolemic shock., Results: IL-4 enhancement of histamine-induced VE barrier dysfunction was associated with increased VE-cadherin degradation, intracellular calcium flux, and phosphorylated Src levels and required transcription and de novo protein synthesis. RNA sequencing analyses of IL-4-stimulated VE cells identified dysregulation of genes involved in cell proliferation, cell development, and cell growth, and transcription factor motif analyses revealed a significant enrichment of differential expressed genes with putative STAT3 and STAT6 motif. IL-4 stimulation in EA.hy926 cells induced both serine residue 727 and tyrosine residue 705 phosphorylation of STAT3. Genetic and pharmacologic ablation of VE STAT3 activity revealed a role for STAT3 in basal VE barrier function; however, IL-4 enhancement and histamine-induced VE barrier dysfunction was predominantly STAT3 independent. In contrast, IL-4 enhancement and histamine-induced VE barrier dysfunction was STAT6 dependent. Consistent with this finding, pharmacologic knockdown of STAT6 abrogated IL-4-mediated amplification of histamine-induced hypovolemia., Conclusions: These studies unveil a novel role of the IL-4/STAT6 signaling axis in the priming of VE cells predisposing to exacerbation of histamine-induced anaphylaxis., Competing Interests: Disclosure statement This work was supported by National Institutes of Health grants DK073553, DK090119, AI138177, and AI112626; Food Allergy Research & Education; Department of Defense grant W81XWH-15-1-051730; Michigan Food Allergy Research Accelerator (M-FARA); and the Mary H. Weiser Food Allergy Center (to S.P.H.). Disclosure of potential conflicts of interest: S.P. Hogan receives research grant support from Regeneron Pharmaceuticals. The remaining authors declare that they have no relevant conflicts of interest., (Copyright © 2024 American Academy of Allergy, Asthma & Immunology. Published by Elsevier Inc. All rights reserved.)