Nfil3 Is a Glucocorticoid-Regulated Gene Required for Glucocorticoid-Induced Apoptosis in Male Murine T Cells
Nfil3 Is a Glucocorticoid-Regulated Gene Required for Glucocorticoid-Induced Apoptosis in Male Murine T Cells
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DOI：
10.1210/en.2012-1820
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发表时间：
2013-04-01
期刊：
影响因子：
4.8
通讯作者：
Cole, Timothy J.
中科院分区：
文献类型：
--
作者：
Carey, Kirstyn T.;Tan, Kheng H.;Cole, Timothy J.
糖皮质激素（GCs）主要通过糖皮质激素受体（GR）起作用，在发育、综合代谢、免疫和神经反应的调节中发挥重要作用。在大多数细胞中，GC处理通过负反馈机制导致GR mRNA和蛋白水平下调。然而，在gc处理的胸腺细胞中，GR蛋白水平维持在高水平，增加了胸腺细胞对gc的敏感性，导致细胞凋亡，称为糖皮质激素诱导的细胞死亡（GICD）。CD4(+) CD8（+）双阳性胸腺细胞和胸腺自然杀伤T细胞对GICD高度敏感。虽然GICD是通过使用合成GC类似物来治疗造血恶性肿瘤，但GICD的细胞内分子途径尚不清楚。为了探索胸腺细胞中的GICD，作者在地塞米松治疗后3小时对小鼠GR外显子2 null与野生型胸腺RNA进行了全基因组表达微阵列分析。已确定和验证的直接GR靶点包括P21和Bim，以及一个重要的转录调节因子Nfil3， Nfil3先前与GICD相关，对体内自然杀伤细胞的发育至关重要。全胸腺NFIL3免疫染色将NFIL3主要定位于髓质区，双标记将NFIL3定位于凋亡细胞。计算机分析显示，在Nfil3启动子上游5kb处存在一个假定的GC应答元件，该元件在大鼠基因组中高度保守，并通过染色质免疫沉淀证实与GR结合。使用特异性小干扰rna将Nfil3 mRNA水平下调至正常水平的20%可消除GICD，这表明Nfil3是CTLL-2 T细胞正常GICD所必需的。（内分泌学154:1540-1552,2013）
Glucocorticoids (GCs) have essential roles in the regulation of development, integrated metabolism, and immune and neurological responses, and act primarily via the glucocorticoid receptor (GR). In most cells, GC treatment results in down-regulation of GR mRNA and protein levels via negative feedback mechanisms. However, in GC-treated thymocytes, GR protein levels are maintained at a high level, increasing sensitivity of thymocytes to GCs, resulting in apoptosis termed glucocorticoid-induced cell death (GICD). CD4(+) CD8(+) double-positive thymocytes and thymic natural killer T cells in particular are highly sensitive to GICD. Although GICD is exploited via the use of synthetic GC analogues in the treatment of hematopoietic malignancies, the intracellular molecular pathway of GICD is not well understood. To explore GICD in thymocytes, the authors performed whole genome expression microarray analysis in mouse GR exon 2 null vs wild-type thymus RNA 3 hours after dexamethasone treatment. Identified and validated direct GR targets included P21 and Bim, in addition to an important transcriptional regulator Nfil3, which previously has been associated with GICD and is essential for natural killer cell development in vivo. Immunostaining of NFIL3 in whole thymus localized NFIL3 primarily to the medullary region, and double labeling colocalized NFIL3 to apoptotic cells. In silico analysis revealed a putative GC response element 5 kb upstream of the Nfil3 promoter that is strongly conserved in the rat genome and was confirmed to bind GR by chromatin immunoprecipitation. The knockdown of Nfil3 mRNA levels to 20% of normal using specific small interfering RNAs abrogated GICD, indicating that NFIL3 is required for normal GICD in CTLL-2 T cells. (Endocrinology 154: 1540-1552, 2013)