由革蘭氏陰性細菌產物脂多糖激活的巨噬細胞,核心代謝從氧化磷酸化轉化至糖酵解。近日一個研究小組一項成果表明,小鼠巨噬細胞中,2-脫氧葡萄糖對糖酵解的抑制,抑制了脂多糖誘導的白細胞介素-1β(IL-1β),而非腫瘤壞死因子α(TNF-α)。相關研究論文于2013年3月24日在線發表在Nature雜志上。
脂多糖激活的巨噬細胞完整代謝圖表明,糖酵解基因表達上調,線粒體基因表達下調,這和代謝產物表達譜相關。脂多糖增加了三羧酸循環中琥珀酸(succinate)的水平。依賴回補反應(anerplerosis)是琥珀酸的主要來源,盡管‘GABA (γ-aminobutyric acid) shunt’ 也發揮一定作用。
脂多糖誘導琥珀酸穩定了缺氧誘導因子-1 ,以IL-1β為靶標,可被2-脫氧葡萄糖抑制。脂多糖也增加的幾種蛋白質的琥珀酰化。因此,研究人員確定琥珀酸是先天免疫信號的代謝物,應對炎癥過程時,它可以提高白細胞介素-1β的產量
原文摘要:
Succinate is an inflammatory signal that induces IL-1β through HIF-1α
Macrophages activated by the Gram-negative bacterial product lipopolysaccharide switch their core metabolism from oxidative phosphorylation to glycolysis1. Here we show that inhibition of glycolysis with 2-deoxyglucose suppresses lipopolysaccharide-induced interleukin-1β but not tumour-necrosis factor-α in mouse macrophages. A comprehensive metabolic map of lipopolysaccharide-activated macrophages shows upregulation of glycolytic and downregulation of mitochondrial genes, which correlates directly with the expression profiles of altered metabolites. Lipopolysaccharide strongly increases the levels of the tricarboxylic-acid cycle intermediate succinate. Glutamine-dependent anerplerosis is the principal source of succinate, although the ‘GABA (γ-aminobutyric acid) shunt’ pathway also has a role. Lipopolysaccharide-induced succinate stabilizes hypoxia-inducible factor-1α, an effect that is inhibited by 2-deoxyglucose, with interleukin-1β as an important target. Lipopolysaccharide also increases succinylation of several proteins. We therefore identify succinate as a metabolite in innate immune signalling, which enhances interleukin-1β