Ponec M, Williams M L
Arch Dermatol Res. 1986;279(1):32-6. doi: 10.1007/BF00404355.
Cholesterol sulfate-cholesterol homeostasis in the epidermis may be important for normal desquamation. Recent evidence from cell-culture studies indicates that cholesterol sulfate inhibits sterologenesis by inhibiting the activity of 3-hydroxy-3-methylglutaryl coenzyme A reductase, the rate-limiting enzyme in cholesterol synthesis. For cholesterol sulfate in the stratum corneum to function as a feedback regulator of epidermal sterologenesis, it must have the capacity enter cells. In these studies, uptake and outflux of cholesterol sulfate was examined in cultured human foreskin keratinocytes, and compared with uptake and outflux of cholesterol and 25-hydroxycholesterol, as well as with sterol uptake by another cell type, the skin fibroblast. The uptake of the free (not lipoprotein-associated) form of all three sterols was not consistent with a receptor-mediated process. Although the cholesterol sulfate uptake was approximately three-fold less than that of 25-hydroxycholesterol, it was nearly seven-fold greater than that of cholesterol itself. Whereas 25-hydroxycholesterol was rapidly washed out of keratinocytes in outflux experiments, both cholesterol and cholesterol sulfate tended to remain cell-associated. These studies demonstrate that cholesterol sulfate is readily taken up by keratinocytes, in which it may be in a position to modulate cellular lipid metabolism.
表皮中胆固醇硫酸酯-胆固醇的稳态对于正常脱屑可能很重要。细胞培养研究的最新证据表明，胆固醇硫酸酯通过抑制3-羟基-3-甲基戊二酰辅酶A还原酶（胆固醇合成中的限速酶）的活性来抑制甾醇生成。为了使角质层中的胆固醇硫酸酯作为表皮甾醇生成的反馈调节剂发挥作用，它必须具有进入细胞的能力。在这些研究中，检测了培养的人包皮角质形成细胞中胆固醇硫酸酯的摄取和流出，并与胆固醇和25-羟基胆固醇的摄取和流出以及另一种细胞类型皮肤成纤维细胞的甾醇摄取进行了比较。所有三种甾醇的游离（非脂蛋白相关）形式的摄取与受体介导的过程不一致。尽管胆固醇硫酸酯的摄取比25-羟基胆固醇少约三倍，但它比胆固醇本身的摄取几乎大七倍。在流出实验中，25-羟基胆固醇很快从角质形成细胞中被洗脱出来，而胆固醇和胆固醇硫酸酯都倾向于与细胞结合。这些研究表明，胆固醇硫酸酯很容易被角质形成细胞摄取，在其中它可能能够调节细胞脂质代谢。
