Department of Medicine, Division of Endocrinology, Johns Hopkins University School of Medicine, Baltimore, Maryland 21215, USA.
Endocrinology. 2010 Nov;151(11):5519-27. doi: 10.1210/en.2010-0347. Epub 2010 Sep 15.
Our goal was to examine the effect of deficiency of the lipoprotein receptor, scavenger receptor class B type I (SR-BI), on progesterone secretion in human granulosa cells (HGL5). Scrambled or SR-BI small interfering RNA [knockdown (KD)] cells were exposed to dimethylsulfoxide [DMSO, vehicle for forskolin (Fo)], Fo, serum, high-density lipoprotein, low-density lipoprotein (LDL), or Fo plus lipoproteins or serum for 24 h. Progesterone secretion was lower in all of the SR-BI KD cells regardless of treatment. We examined progesterone secretion in SR-BI KD, LDL receptor KD, and double KD cells incubated with DMSO, Fo, LDL, or Fo + LDL for 6-24 h. As compared with scrambled cells, progesterone secretion was lower in SR-BI and double KD cells regardless of treatment; whereas progesterone secretion was only lower in LDL receptor KD cells incubated with LDL and Fo + LDL. We measured phosphorylation of hormone-sensitive lipase (pHSL) expression, intracellular total cholesterol (TC) mass, and progesterone secretion in scrambled and SR-BI KD cells incubated with DMSO or Fo for 2-24 h. The expression of pHSL was similar between the cells and conditions. The mean change in TC mass and progesterone secretion was lower in SR-BI KD cells exposed to DMSO and Fo. Incubating SR-BI KD cells with 22-hydroxy cholesterol did not overcome the reduction in progesterone secretion. At different time points, RNA expression of steroidogenic acute regulatory protein, side-chain cleavage, and 3β-hydroxysteroid dehydrogenase was significantly lower in SR-BI KD cells incubated with Fo. In conclusion, SR-BI protein deficiency, in part, might explain progesterone deficiency in some infertile women.
我们的目的是研究脂蛋白受体(scavenger receptor class B type I，SR-BI)缺失对人颗粒细胞(human granulosa cells，HGL5)孕激素分泌的影响。用 scramble 或 SR-BI 小干扰 RNA [敲低(kill down，KD)]细胞暴露于二甲基亚砜(dimethylsulfoxide，DMSO，作为 forskolin [Fo]的溶剂)、Fo、血清、高密度脂蛋白(high-density lipoprotein)、低密度脂蛋白(low-density lipoprotein，LDL)或 Fo 加脂蛋白或血清中 24 小时。无论是否进行处理，所有 SR-BI KD 细胞的孕激素分泌均降低。我们在 SR-BI KD、低密度脂蛋白受体(low density lipoprotein receptor，LDLR) KD 和双重 KD 细胞中检测了用 DMSO、Fo、LDL 或 Fo+LDL 孵育 6-24 小时后的孕激素分泌情况。与 scramble 细胞相比，无论是否进行处理，SR-BI 和双重 KD 细胞的孕激素分泌均降低；而只有在用 LDL 和 Fo+LDL 孵育时，LDLR KD 细胞的孕激素分泌才降低。我们测量了 scramble 和 SR-BI KD 细胞在 DMSO 或 Fo 孵育 2-24 小时后激素敏感脂肪酶(hormone-sensitive lipase，HSL)表达、细胞内总胆固醇(total cholesterol，TC)质量和孕激素分泌的磷酸化情况。细胞和条件之间的 HSL 表达相似。暴露于 DMSO 和 Fo 的 SR-BI KD 细胞的 TC 质量和孕激素分泌的平均变化较低。用 22-羟胆固醇孵育 SR-BI KD 细胞并不能克服孕激素分泌减少的问题。在不同时间点，用 Fo 孵育的 SR-BI KD 细胞的类固醇急性调节蛋白(steroidogenic acute regulatory protein，StAR)、侧链切割酶(side-chain cleavage，P450scc)和 3β-羟甾脱氢酶(3β-hydroxysteroid dehydrogenase，3β-HSD)的 RNA 表达明显降低。总之，SR-BI 蛋白缺乏可能部分解释了一些不孕妇女的孕激素缺乏。
