A genome-wide expression profile of steroidogenic cells selectively isolated from adrenal glands of knockout mice lacking steroidogenic acute regulatory protein

Steroidogenic acute regulatory protein (Star) facilitates cholesterol transfer into the inner mitochondrial membrane in the acute and regulated production of steroid hormones. Mice lacking Star (Star-/-) share the phenotypes with patients with congenital lipoid adrenal hyperplasia such as compromised production of steroid hormones and florid accumulation of cholesterol esters in adrenal glands and gonads. To define specific patterns of molecular changes with disruption of Star, we performed a transcriptome analysis of steroidogenic cells in adrenal glands. We harvested adrenal glands at E17.5 or 18.5 from seven wild-type (Star+/+) mice or four Star-/- mice having the transgene targeting enhanced green fluorescent protein (eGFP) under the control of regulatory sequences of mouse Star gene. Steroidogenic cells were selectively isolated by fluorescent-activated cell sorting. The gene expression profile of the fluorescence-positive cells was obtained with Agilent Whole Mouse Genome Microarray and was confirmed by quantitative real-time PCR. We identified 961 and 622 genes that were significantly up-regulated and down-regulated, respectively, in Star-/- mice compared with Star+/+ mice (fold difference >= 2, p value of Student t test <0.05, and Benjamini-Hochberg false discovery rate of multiple comparison test <0.2). In Star-/- mice, expression levels of genes involved in cholesterol mobilization and efflux or immune response as antigen presenting cells were significantly increased, and transition from fetal to adult adrenocortical cells were significantly decreased, whereas those of genes related to steroid hormone biosynthesis or cholesterol biosynthesis and influx were not significantly changed. The trancriptome analysis revealed hitherto undescribed characteristic changes in adrenocortical cells and expanded our understanding of the pathophysiology of the steroidogenic cells with disruption of Star. Gene expression profiles of isolated adrenal steroidogenic cells were compared between seven wild-type mice and four knockout mice lacking steroidogenic acute regulatory protein at E17.5-18.5.类固醇生成急性调节蛋白（Steroidogenic acute regulatory protein, Star）可在类固醇激素的急性调控合成过程中，介导胆固醇向线粒体内膜转运。缺失Star的小鼠（Star-/-）其表型与先天性类脂质性肾上腺增生症患者高度相似，表现为类固醇激素合成受损，以及肾上腺和性腺内大量蓄积胆固醇酯。 为明确Star基因敲除后分子变化的特异性模式，我们对肾上腺类固醇生成细胞开展了转录组分析。我们从7只野生型（Star+/+）小鼠，以及4只携带以小鼠Star基因调控序列驱动增强绿色荧光蛋白（enhanced green fluorescent protein, eGFP）转基因的Star-/-小鼠中，于胚胎发育第17.5天（E17.5）或第18.5天（E18.5）采集肾上腺组织。通过荧光激活细胞分选术（fluorescent-activated cell sorting, FACS）选择性分离得到类固醇生成细胞。采用安捷伦全小鼠基因组微阵列（Agilent Whole Mouse Genome Microarray）获取荧光阳性细胞的基因表达谱，并通过实时定量PCR（quantitative real-time PCR, qPCR）完成验证。 与Star+/+小鼠相比，Star-/-小鼠中共有961个基因显著上调、622个基因显著下调（差异倍数≥2，Student t检验p值<0.05，多重比较检验的Benjamini-Hochberg错误发现率<0.2）。在Star-/-小鼠体内，参与胆固醇动员、外流或作为抗原呈递细胞的免疫应答相关基因的表达水平显著升高；胎儿肾上腺皮质细胞向成人型转化的相关基因表达则显著下调，而类固醇激素生物合成、胆固醇生物合成及内流相关基因的表达无显著变化。 本转录组分析揭示了肾上腺皮质细胞中此前未被报道的特征性分子变化，拓展了我们对Star基因敲除所致类固醇生成细胞病理生理机制的认知。本数据集对比了7只野生型小鼠与4只Star基因敲除小鼠在胚胎发育第17.5至18.5天（E17.5~E18.5）时期分离得到的肾上腺类固醇生成细胞的基因表达谱。