Huyton Trevor, Göttmann Wiebke, Bade-Döding Christina, Paine Ananta, Blasczyk Rainer
Institute for Transfusion Medicine, Hannover Medical School, Germany.
Biochim Biophys Acta. 2011 Dec;1810(12):1294-301. doi: 10.1016/j.bbagen.2011.06.020. Epub 2011 Jul 1.
SECTM1 is a T/NK cell "co-stimulatory" molecule that is expressed in the peripheral blood by neutrophils and monocytes.
We used qRT-PCR to investigate the mRNA expression of SECTM1 in human monocytic cells after stimulation with interferons and LPS and confirmed the protein expression by flow cytometry.
The kinetics of interferon induced SECTM1 mRNA expression in MM6 cells are time dependent occurring rapidly within 3h of stimulation and reaching a maximal level at ~6h for IFN-α and ~12h for IFN-β and IFN-γ. Co-treatment of MM6 cells with IFN-γ and cycloheximide caused a superinduction of SECTM1 mRNA expression while cycloheximide alone had no effect, illustrating that de novo protein synthesis is not required for IFN-γ enhanced expression of SECTM1 mRNA, a characteristic of IFN early response genes. The kinetics of IFN induced SECTM1 mRNA expression in primary monocytes is comparable although it occurs much quicker with rapid induction by IFN-α, IFN-β and IFN-γ and maximal levels reached in <6h. Human monocytic cells also displayed a pronounced negative regulation of SECTM1 mRNA expression by LPS, while at the protein level SECTM1 expression was also shown to be regulated by IFN and LPS. Bioinformatic analysis of the SECTM1 promoter region identified STAT1α/GAS, STAT3, ISRE, NFκB and putative p63 binding sites suggesting a complex transcriptional control. This tight regulation of SECTM1 gene expression and rapid upregulation highlights its relevance in the innate immune response.
Human monocytes produce SECTM1 in response to interferon stimuli that is negatively regulated by LPS.
The level of SECTM1 expression is likely to be a key factor in innate immune responses and in the immune tolerance of cancerous cells.
SECTM1是一种T/NK细胞“共刺激”分子，由中性粒细胞和单核细胞在外周血中表达。
我们使用qRT-PCR研究干扰素和LPS刺激后人单核细胞中SECTM1的mRNA表达，并通过流式细胞术确认蛋白表达。
干扰素诱导MM6细胞中SECTM1 mRNA表达的动力学是时间依赖性的，在刺激后3小时内迅速发生，IFN-α在约6小时达到最大水平，IFN-β和IFN-γ在约12小时达到最大水平。IFN-γ与环己酰亚胺共同处理MM6细胞导致SECTM1 mRNA表达超诱导，而单独使用环己酰亚胺则无影响，这表明IFN-γ增强SECTM1 mRNA表达不需要从头合成蛋白质，这是IFN早期反应基因的一个特征。IFN诱导原代单核细胞中SECTM1 mRNA表达的动力学具有可比性，尽管IFN-α、IFN-β和IFN-γ诱导更快，且在<6小时内达到最大水平。人单核细胞也显示出LPS对SECTM1 mRNA表达有明显的负调控，而在蛋白水平上，SECTM1表达也显示受IFN和LPS调控。对SECTM1启动子区域的生物信息学分析确定了STAT1α/GAS、STAT3、ISRE、NFκB和假定的p63结合位点，提示存在复杂的转录调控。SECTM1基因表达的这种严格调控和快速上调突出了其在先天免疫反应中的相关性。
人单核细胞在干扰素刺激下产生SECTM1，LPS对其有负调控作用。
SECTM1的表达水平可能是先天免疫反应和癌细胞免疫耐受的关键因素。
