Mechanism Of FoxO1 In Promoting Allergic Asthma Progression Through Inhibiting Regulatory B Cell Development

Asthma is an allergy disease that affects 300 million people worldwide.For Immunological pathogenesis,asthma is mainly mediated by Th2 response for which most clinical immunotherapy methods were developed.In recent years,the role of B cells in asthma has gradually been of concern.B cells produce pathogenic immunoglobulin IgE in asthma.Meanwhile,a new subpopulation of B cells,B10 cells,which secrete IL-10,play an antiinflammatory role in a variety of diseases.It has been reported that the PI3K-Akt pathway affects the differentiation of B10 cells,while FoxO1,a key downstream factor of this pathway,has not been reported on the differentiation process of B10 cells.Based on the background above,this study focuses on how FoxO1 affects the differentiation of B10 cells,and further explores the possibility of immunosuppressive therapy of asthma by regulating B cells via targeting FoxO1。The main results obtained are as follows:1.FoxO1 expression is upregulated in B cells during allergy asthmaIn peripheral blood of allergy asthma patients,we find that FoxO1 activity of B cells is upregulated and the percentage of B10 cells is decreased.Lung tissue samples from clinical asthmatic patients are difficult to obtain,so we also detect the phenotype of lung tissue in asthma mouse models and find a similar phenomenon.2.FoxO1 inhibits B10 cell differentiationIn vitro experiments,we find that FoxO1-deficient B cell have stronger IL-10 producing and secretion ability.In vivo,FoxO1 activity of B cells is reduced during differentiation to B10 cells.The proportion of B10 cells is increased in FoxO1-deficient B cell mice.3.Prdm1 is a key transcription factor during FoxO1 regulation of B10 differentiationSingle-cell RNA sequencing data suggests that FoxO1 inhibits IL-10 expression by regulating Prdm1 in mouse spleen,lung and human lung B cells.In vitro,we confirm that FoxO1 inhibit the differentiation of B10 cells by down-regulate Prdm1.4.FoxO1 affects the secretion of IgE via IL-10 dependently or independentlyAs a key pathogenic immunoglobulin in asthma,FoxO1-deficient B cell directly inhibits IgE secretion in vitro.At the same time,IL-10 also directly inhibits IgE secretion of B cells in vitro.5.B-cell specific knockout of FoxO1 alleviates asthma diseaseIn a treatment experiment,we find that B-cell specific FoxO1 deletion alleviates symptoms in a mouse asthma model.Eosinophils and alveolar macrophages in the lungs of bcell-specific FoxO1-deficient mice significantly decreased,the Th2 response decreased,the percentage of B cells significantly increased,while also accompanied by an increased percentage of B10 cells.These results suggest that B10 cells are involved in the remission of Th2 response in asthma.6.Asthma of Wild-type mice is alleviated by adoptive transferred FoxO1-specific knockout B cellsIn a transfer experiment,we find that FoxO1-knockout B cells could directly inhibit asthma disease in the excitation stage.This result proves that targeting FoxO1 for affecting the differentiation of B cells into B10 can alleviate asthma disease independently of IgE which provide a new site for clinical cell-targeted allergy asthma therapy.