Bongartz H, Bradfield C, Gross J, Fraser I D C, Nita-Lazar A, Meier-Schellersheim M
Computational Systems Biology Section, Laboratory of Immune System Biology, National Institute of Allergy and infectious Diseases, National Institutes of Health, Bethesda, MD, USA.
Signaling Systems Section, Laboratory of Immune System Biology, National Institute of Allergy and infectious Diseases, National Institutes of Health, Bethesda, MD, USA.
bioRxiv. 2024 Mar 31:2024.03.28.587272. doi: 10.1101/2024.03.28.587272.
During an infection, innate immune cells must adjust nature and strength of their responses to changing pathogen abundances. To determine how stimulation of the pathogen sensing TLR4 shapes subsequent macrophage responses, we systematically varied priming and restimulation concentrations of its ligand KLA. We find that different priming strengths have very distinct effects at multiple stages of the signaling response, including receptor internalization, MAPK activation, cytokine and chemokine production, and nuclear translocation and chromatin association of NFκB and IκB members. In particular, restimulation-induced TNF-α production required KLA doses equal to or greater than those used for prior exposure, indicating that macrophages can detect and adaptively respond to changing TLR4 stimuli. Interestingly, while such adaptation was dependent on the anti-inflammatory cytokine IL-10, exogenous concentrations of IL-10 corresponding to those secreted after strong priming did not exert suppressive effects on TNF-α without such prior priming, confirming the critical role of TLR4 stimulation history.
在感染过程中,固有免疫细胞必须根据病原体丰度的变化调整其反应的性质和强度。为了确定病原体传感Toll样受体4(TLR4)的刺激如何塑造随后的巨噬细胞反应,我们系统地改变了其配体脂多糖(KLA)的预刺激和再刺激浓度。我们发现,不同的预刺激强度在信号反应的多个阶段具有非常不同的作用,包括受体内化、丝裂原活化蛋白激酶(MAPK)激活、细胞因子和趋化因子产生,以及核因子κB(NFκB)和核因子κB抑制蛋白(IκB)成员的核转位和染色质结合。特别是,再刺激诱导的肿瘤坏死因子-α(TNF-α)产生需要KLA剂量等于或大于先前暴露所用剂量,这表明巨噬细胞可以检测并适应性地应对不断变化的TLR4刺激。有趣的是,虽然这种适应性依赖于抗炎细胞因子白细胞介素-10(IL-10),但在没有这种先前预刺激的情况下,与强烈预刺激后分泌的IL-10浓度相当的外源性IL-10对TNF-α没有抑制作用,这证实了TLR4刺激历史的关键作用。