FSH and FOXO1 Regulate Genes in the Sterol/Steroid and Lipid Biosynthetic Pathways in Granulosa Cells
FSH and FOXO1 Regulate Genes in the Sterol/Steroid and Lipid Biosynthetic Pathways in Granulosa Cells
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DOI：
10.1210/me.2008-0412
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发表时间：
2009-05-01
影响因子：
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通讯作者：
Richards, JoAnne S.
中科院分区：
文献类型：
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作者：
Liu, Zhilin;Rudd, Michael D.;Richards, JoAnne S.
叉头盒转录因子FOXO1在生长卵泡的颗粒细胞中高表达，但在培养中被FSH下调，或在体内被黄体生成素诱导的黄体生成下调。为了分析FOXO1的功能，我们用表达两个FOXO1突变体的腺病毒载体感染大鼠和小鼠颗粒细胞：一个功能获得突变体FOXOA3，含有两个丝氨酸残基和一个苏氨酸残基，突变为丙氨酸，使该蛋白具有组成活性和核，以及FOXOA3突变的DNA结合结构域(MDBD)，其中DBD发生突变。然后用赋形剂或促卵泡激素处理感染细胞特定的时间间隔。颗粒细胞的感染效率很高，只引起极少量的细胞凋亡，并将FOXO1蛋白维持在暴露于FSH之前观察到的细胞内源性蛋白的水平。Affymetrix微阵列和数据库分析及实时RT-PCR验证表明，脂类、类固醇和类固醇合成途径(Hmgcs1、Hmgcr、MVK、Sqle、LSS、Cyp51、Tm7sf2、Dhcr24和Star、Cyp11a1和Cyp19)中的基因是FSH诱导和抑制颗粒细胞胆固醇生物合成和类固醇合成的两个关键转录调控因子(Nr5a1和Nr5a2)的主要靶点。相比之下，FOXOA3和FOXOA3-mDBD诱导了Cyp27a1 mRNA的表达，Cyp27a1编码一种参与胆固醇分解代谢为氧固醇的酶。用马绒毛膜促性腺激素(FSH)和人绒毛膜促性腺激素(LH)分别诱导幼鼠卵泡颗粒细胞和黄体颗粒细胞表达FSH上调的基因。相反，同样的处理降低了Foxo1和Cyp27a1的mRNAs。总之，这些数据提供了新的证据，表明FOXO1可能在颗粒细胞中发挥关键作用，调节脂质和类固醇的生物合成，从而防止卵泡发育早期激素合成的增加。(分子内分泌学23：649-661,2009)
The forkhead box transcription factor FOXO1 is highly expressed in granulosa cells of growing follicles but is down-regulated by FSH in culture or by LH-induced luteinization in vivo. To analyze the function of FOXO1, we infected rat and mouse granulosa cells with adenoviral vectors expressing two FOXO1 mutants: a gain-of-function mutant FOXOA3 that has two serine residues and one threonine residue mutated to alanines rendering this protein constitutively active and nuclear and FOXOA3-mutant DNA-binding domain (mDBD) in which the DBD is mutated. The infected cells were then treated with vehicle or FSH for specific time intervals. Infection of the granulosa cells was highly efficient, caused only minimal apoptosis, and maintained FOXO1 protein at levels of the endogenous protein observed in cells before exposure to FSH. RNA was prepared from control and adenoviral infected cells exposed to vehicle or FSH for 12 and 24 h. Affymetrix microarray and database analyses identified, and real time RT-PCR verified, that genes within the lipid, sterol, and steroidogenic biosynthetic pathways (Hmgcs1, Hmgcr, Mvk, Sqle, Lss, Cyp51, Tm7sf2, Dhcr24 and Star, Cyp11a1, and Cyp19), including two key transcriptional regulators Srebf1 and Srebf2 of cholesterol biosynthesis and steroidogenesis (Nr5a1, Nr5a2), were major targets induced by FSH and suppressed by FOXOA3 and FOXOA3-mDBD in the cultured granulosa cells. By contrast, FOXOA3 and FOXOA3-mDBD induced expression of Cyp27a1 mRNA that encodes an enzyme involved in cholesterol catabolism to oxysterols. The genes up-regulated by FSH in cultured granulosa cells were also induced in granulosa cells of preovulatory follicles and corpora lutea collected from immature mice primed with FSH (equine choriogonadotropin) and LH (human choriogonadotropin), respectively. Conversely, Foxo1 and Cyp27a1 mRNAs were reduced by these same treatments. Collectively, these data provide novel evidence that FOXO1 may play a key role in granulosa cells to modulate lipid and sterol biosynthesis, thereby preventing elevated steroidogenesis during early stages of follicle development. (Molecular Endocrinology 23: 649-661, 2009)