17β-hydroxysteroid dehydrogenase type XI localizes to human steroidogenic cells
17β-hydroxysteroid dehydrogenase type XI localizes to human steroidogenic cells
复制标题
DOI：
10.1210/en.2002-221030
复制
发表时间：
2003-05-01
期刊：
影响因子：
4.8
通讯作者：
Krozowski, Z
中科院分区：
文献类型：
--
作者：
Chai, ZL;Brereton, P;Krozowski, Z
我们搜索了含有短链乙醇脱氢酶超家族保守结构域的表达序列标签数据库，并鉴定出另一种17β-羟基类固醇脱氢酶亚型17betaHSDXI。这种酶将5α-雄烷-3α，17β-二醇转化为雄酮。该底物被认为具有支持妊娠和调节γ-氨基丁酸受体活性的作用。17XHSDXI与人视网膜短链脱氢酶/还原酶retSDR2共线，这是一个没有已知生物活性的蛋白质(登录号：AAF06939)。在已知功能的蛋白质中，17betaHSDXI与视黄醇代谢酶retSDR1关系最密切，有30%的同源性。在该序列的5‘非翻译区有15个腺苷的多态延伸，在C719T有一个沉默的多态。含有20个腺苷的17betaHSDXI构建体比含有15个或更少腺苷的构建体产生更多的酶活性(43%vs.26%，P<；0.005)。C719T多态存在于15%的基因组DNA样本中。Northern印迹分析表明，17βHSDXI在胰腺、肾脏、肝脏、肺、肾上腺、卵巢和心脏中高水平表达。17βHSDXI免疫组织化学染色在合体滋养层细胞、皮脂腺、间质细胞、优势卵泡颗粒细胞和黄体颗粒细胞等类固醇生成细胞中表达较强。在肾上腺17βHSDXI，染色与17α羟基酶共同分布，但在中、外皮质染色较强。17βHSDXI在胎儿中也有表达，并在出生后升高。肝实质细胞、子宫内膜和小肠上皮细胞也被染色。在小鼠Y1细胞中的调节研究表明，cAMP下调17βHSDXI酶活性(40%比32%，P<；0.05)，并将基因表达降低到检测不到的水平。全反式维甲酸对17betaHSDXI的表达或活性没有影响，但加入维甲酸和cAMP一起显著降低了cAMP的活性(32%比23%，P<；0.05)。17βHSDXI启动子的克隆和测序证实了潜在的核受体类固醇生成因子-1半区TCCAAGGCCGG，在内含子1的远端还发现了另外三个潜在的类固醇生成因子-1半位点。这些结果提示，17βHSDXI在类固醇合成过程中可能参与雄激素代谢，并可能在非类固醇生成组织中发挥作用，包括旁分泌调节5α-雄烷-3α、17β-二醇水平。17βHSDXI可以通过代谢刺激类固醇合成的化合物和/或通过产生抑制类固醇合成的代谢物来发挥作用。
We searched expressed sequence tag databases with conserved domains of the short-chain alcohol dehydrogenase superfamily and identified another isoform of 17beta-hydroxysteroid dehydrogenase, 17betaHSDXI. This enzyme converts 5alpha-androstane-3alpha, 17beta-diol to androsterone. The substrate has been implicated in supporting gestation and modulating gamma-aminobutyric acid receptor activity. 17XHSDXI is colinear with human retinal short-chain dehydrogenase/reductase retSDR2, a protein with no known biological activity (accession no. AAF06939). Of the proteins with known function, 17betaHSDXI is most closely related to the retinol-metabolizing enzyme retSDR1, with which it has 30% identity. There is a polymorphic stretch of 15 adenosines in the 5' untranslated region of the cDNA sequence and a silent polymorphism at C719T. A 17betaHSDXI construct with a stretch of 20 adenosines was found to produce significantly more enzyme activity than constructs containing 15 or less adenosines (43% vs. 26%, P < 0.005). The C719T polymorphism is present in 15% of genomic DNA samples. Northern blot analysis showed high levels of 17βHSDXI expression in the pancreas, kidney, liver, lung, adrenal, ovary, and heart. Immunohistochemical staining for 17βHSDXI is strong in steroidogenic cells such as syncytiotrophoblasts, sebaceous gland, Leydig cells, and granulosa cells of the dominant follicle and corpus luteum. In the adrenal 17βHSDXI, staining colocalized with the distribution of 17α-hydroxylase but was stronger in the mid to outer cortex. 17βHSDXI was also found in the fetus and increased after birth. Liver parenchymal cells and epithelium of the endometrium and small intestine also stained. Regulation studies in mouse Y1 cells showed that cAMP down-regulates 17βHSDXI enzymatic activity (40% vs. 32%, P < 0.05) and reduces gene expression to undetectable levels. All-trans-retinoic acid did not affect 17betaHSDXI expression or activity, but addition of the retinoid together with cAMP significantly decreased activity over cAMP alone (32% vs. 23%, P < 0.05). Cloning and sequencing of the 17βHSDXI promoter identified the potential nuclear receptor steroidogenic factor-1 half-site TCCAAGGCCGG, and a cluster of three other potential steroidogenic factor-1 half-sites were found in the distal part of intron 1. Collectively, these results suggest a role for 17βHSDXI in androgen metabolism during steroidogenesis and a possible role in nonsteroidogenic tissues including paracrine modulation of 5α-androstane-3α, 17β-diol levels. 17βHSDXI could act by metabolizing compounds that stimulate steroid synthesis and/or by generating metabolites that inhibit it.