SIRT1抑制细菌脂多糖耐受THP-1细胞中IL-1βmRNA的转录

SIRT1 inhibits IL-1β mRNA transcription in lipopolysaccharide tolerant THP-1 cells

目的研究细菌脂多糖（LPS）耐受的THP-1细胞中沉默信息调节因子1（SIRTl）对IL-1β转录的调节作用。方法使用LPS耐受的人单核细胞THP-1模型，染色体免疫沉淀和real-timePCR定量研究IL-1β启动子区SIRT1结合情况和组蛋白H3lys9／H4lysl6的乙酰化情况。结果在LPS耐受的THP～1细胞中，SIRT1对IL-1β启动子区的结合增加约5倍左右（P〈0．05），同时伴随着组蛋白H3lys9／H4lysl6乙酰化的低水平状态（与正常细胞相比P〈0．05）。SIRT1沉默使IL-1β的转录恢复到正常细胞的68％（P〈0．05），同时伴随着组蛋白H3lys9／H4lysl6乙酰化的增加（P〈0．05）。然而，正常细胞和耐受细胞p65lys310乙酰化水平无明显差异。结论SIRT1抑制LPS耐受的THP—1细胞中IL-1βmRNA的转录，其作用与p65lys310乙酰化无关，但是与IL-1β启动子区乙酰化有关。

Objective To explore the role of silent information regulation 2 homolog 1 （SIRT1） in the regulation of IL-1 β mRNA transcription in lipopolysaccharide （LPS） tolerant THP-1 cells. Methods THP-1 human promonocyte model of endotoxin tolerance that simulates the sepsis leukocyte phenotype was used. Chromatin immunoprecipitation assay （CHIP） and real-time PCR were applied to quantify the binding of SIRT1 and histone H3 lys9/H4 lysl6 acetylation to IL-1β promoter. IL-1 β mRNA transcription was studied after knocking down the SIRT1. Results The binding of SIRT1 to IL-1 β promoter increased about 5 times in tolerant THP-1 cells （P〈0.05）, which was accompanied by the low level of histone H3 lys9/H4 lysl6 acetylation （P〈0.05, compared with normal cells）. Knocking-down of SIRT1 increased the transcription of IL-1 β mRNA up to the level of 68% of normal cells （P〈0.05）, which was accompanied by the increase of histone H3 lys9/H4 lysl 6 acetylation （P〈0.05）. However, there was no significant difference of p65 lys310 acetylation between normal and tolerant cells. Conclusion SIRT1 inhibited the IL-1 β mRNA transcription in tolerant THP-1 ceils but had not related to p65 lys310 acetylation. However, it was related to IL-1β promoter acetylation.