Abstract：
Antibiotic treatment may lead to side effects that require mechanistic explanation. We investigated the effect of azithromycin (AZM) treatment on bone marrow-derived macrophage (Mφ) generation, their functional output, and the subsequent effect on bacterial clearance in a mouse model of S. flexneri infection. To our fascination, AZM increased PU.1, C/EBPβ, CSF-1R/pCSF-1R expressions leading to M2-skewed in vitro BMDM generation. Altered Mφ-functions like- phagocytosis, oxidative stress generation, inflammasome-activation, cytokine release, and phenotype (pro-inflammatory-M1, anti-inflammatory-M2) even in the presence of infection were observed with AZM treatment. AZM increased CD206, egr2, arg1 (M2-marker) expression and activity while reducing CD68, inducible nitric oxide (iNOS) expression, and activity (M1-marker) in Mφs during infection. Pro-inflammatory cytokines (TNF-α, IL-12, IL-1β) were reduced and anti-inflammatory IL-10 release was augmented by AZM-treated-iMφs (aiMφs) along with decreased asc, nlrp3, aim2, nlrp1a, caspase1 expressions, and caspase3 activity signifying that aMφs/aiMφs were primed towards an anti-inflammatory phenotype. Interestingly, CSF-1R blockade increased NO, IL-12, TNF-α, IL-1β, decreased TGF-β release, and CD206 expression in aiMφs. T-cell co-stimulatory molecule cd40, cd86, and cd80 expressions were decreased in ai/aM1-Mφs and co-cultured CD8+, CD4+ T-cells had decreased proliferation, t-bet, IFN-γ, IL-17, IL-2 but increased foxp3, TGF-β, IL-4 which were rescued with CSF-1R blockade. Thus AZM affected Mφ-functions and subsequent T-cell responses independent of its antibacterial actions. This was validated in the balb/c model of S. flexneri infection. We conclude that AZM skewed BMDM generation to anti-inflammatory M2-like via increased CSF-1R expression. This warrants further investigation of AZM-induced altered-Mφ-generation during intracellular infections.
摘要：
抗生素治疗可能导致副作用，需要机械解释。我们研究了阿奇霉素（AZM）治疗对骨髓源性巨噬细胞（Mφ）产生的影响，它们的功能输出，以及随后对福氏链球菌感染小鼠模型中细菌清除的影响。令我们着迷的是，AZM增加PU.1，C/EBPβ，CSF-1R/pCSF-1R表达导致M2偏斜的体外BMDM生成。改变了Mφ功能，如吞噬作用，氧化应激的产生，炎症小体激活，细胞因子释放，甚至在存在感染的情况下，用AZM治疗观察到表型（促炎-M1，抗炎-M2）。AZM增加了CD206，egr2，arg1（M2标记）的表达和活性，同时减少了CD68，诱导型一氧化氮（iNOS）的表达，和感染期间Mφs的活性(M1标记)。促炎细胞因子（TNF-α，IL-12，IL-1β）减少，并且通过AZM处理的iMφs（aiMφs）增加了抗炎IL-10的释放，同时asc减少，nlrp3,aim2,nlrp1a,caspase1表达式，和caspase3活性表明aMφs/aiMφs被引发抗炎表型。有趣的是,CSF-1R阻断增加NO，IL-12,TNF-α,IL-1β,TGF-β释放减少，和CD206在aiMφs中的表达。T细胞共刺激分子cd40，cd86和cd80在ai/aM1-Mφs和共培养的CD8+中表达降低，CD4+T细胞增殖减少，t-bet,IFN-γ，IL-17，IL-2，但增加foxp3，TGF-β，用CSF-1R阻断拯救的IL-4。因此，AZM影响了Mφ功能和随后的T细胞反应，而与其抗菌作用无关。这在福氏链球菌感染的balb/c模型中得到了验证。我们得出的结论是，AZM通过增加的CSF-1R表达使BMDM产生偏向抗炎M2样。这需要进一步研究细胞内感染过程中AZM诱导的Mφ发生改变。
