AB0059 通过MAPK和NF-KB信号通路自动修饰药物抑制白细胞介素-37表达

Abstract

Background Autophagy has been shown as an intrinsic cellular defense mechanism in innate and adaptive immune responses and is reported to regulate inflammation during infection [1], Accumulating evidence indicates that autophagy suppresses inflammasome activation [2-5]. IL-37 has been identified as an anti-inflammatory factor that translocates into the nucleus and downregulates other pro-inflammatory cytokines [6]. Nevertheless, whether autophagy regulates the expression of IL-37 has not been elucidated. Objectives The purpose of this study was to investigate the role of autophagy in regulating IL-37, an anti-inflammatory cytokine highly expressed in tissues of patients with inflammatory and autoimmune diseases. Methods PMA-transformed and LPS-stimulated U937 macrophages were treated with three autophagy-modifying reagents—3MA, chloroquine, and rapamycin. The expression of three IL-1 family cytokines (IL-37, IL-18, and IL-1β) and two receptors (IL-1R8 and IL-18RA) was determined by quantitative PCR. Intracellular IL-37 expression was detected by flow-cytometry. Western blot analysis and immunofluorescence assay were used to determine the levels of P62/SQSTM1 and LC3, and autophagic U937 cells were isolated by sorting for quantifying IL-37 expression. We also used agonists and antagonists of the MAPK and NF-κB pathways to investigate the possible pathway involved. Peripheral blood mononuclear cells from one healthy donor were also used for autophagy modification and intracellular IL-37 quantitation. Results IL-37 was upregulated by rapamycin and chloroquine in U937 cells stimulated by LPS. IL-37 was preferentially expressed in autophagic cells accompanied with LC3 conversion. Higher IL-37 expression was found in ”yto-ID” positive cells than in negative cells. Inductive IL-37 expression, but not constitutive IL-37 expression, could be abolished by inhibitors of the MAPK and NF-κB pathways, whereas it was augmented by MAPK agonists. Conclusion IL-37 levels were enhanced by rapamycin and chloroquine dependent on MAPK and NF-κB pathway activation, probably through LC3 accumulation. This study suggests a possible novel mechanism of chloroquine and rapamycin action in autoimmune inflammatory diseases.