Membrane transporters for sulfated steroid hormones in the testisand their role for spermatogenesis and fertility

循环中的硫化类固醇激素通过摄取载体被输送到靶组织，然后可以被类固醇硫酸酯酶(STS)的催化活性重新激活(“硫脂酶途径”)。虽然众所周知，在人的睾丸中有很高的STS酶活性，DHEAS和PREGS可以被睾丸匀浆代谢成有活性的睾酮，但对类固醇硫酸盐载体在睾丸中的功能、表达和生理意义知之甚少。该项目致力于研究硫化类固醇激素如SOAT、OATP6A1、OATP1C1和OSCP1的膜转运蛋白的表达和调控，这些激素在睾丸和STS中都有优势表达。我们将研究(1)硫酸类固醇载体和STS在人类睾丸中的亚细胞定位，将正常精子发生和睾丸活检与各种病理图像进行比较，以区分表达模式中的病理变化，(2)为每个类固醇硫酸盐载体建立稳定的HEK293细胞系，用于比较功能转运实验，以及(3)分析SOAT、OATP6A1和OATP1C1基因的雄激素依赖的mRNA表达，这些基因在其启动子序列中都显示高度保守的雄激素受体反应元件。拟议的工作计划将为睾丸生理和病理生理的内分泌/内分泌调节的“硫酸盐酶途径”的生理学相关性提供新的见解。

Circulating sulfated steroid hormones are delivered to target tissues via uptake carriers and then can be reactivated by the catalytic activity of the steroid sulfatase (StS) (“sulfatase pathway”). Although it is well known that in the human testis there is a high StS enzyme activity and DHEAS and PREGS can be metabolized to active testosterone by testis homogenates, little is known about the function, expression, and physiological significance of steroid sulfate carriers in the testis. The project is focused on the investigation of expression and regulation of membrane transporters for sulfated steroid hormones such as SOAT, OATP6A1, OATP1C1, and OSCP1 which show predominant expression in the testis as well as StS. We will investigate (1) the subcellular localization of steroid sulfate carriers and StS in the human testis comparing normal spermatogenesis and testicular biopsies with various pathological pictures to discriminate for pathological changes in the expression pattern, (2) generate stable HEK293 cell lines for each of the steroid sulfate carriers for comparative functional transport experiments, and will (3) analyze the androgen-dependent mRNA expression from SOAT, OATP6A1, and OATP1C1 genes, that all show highly conserved androgen-receptor response elements in their promoter sequences. The proposed work plan will provide new insights into the physiological relevance of the “sulfatase pathway” for the endocrine/intracrine regulation of testicular physiology and pathophysiology.