Constitutively active protein kinase a qualitatively mimics the effects of follicle-stimulating hormone on granulosa cell differentiation
Constitutively active protein kinase a qualitatively mimics the effects of follicle-stimulating hormone on granulosa cell differentiation
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DOI：
10.1210/me.2008-0103
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发表时间：
2008-08-01
影响因子：
--
通讯作者：
Zeleznik, Anthony J.
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文献类型：
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作者：
Escamilla-Hernandez, Rosalba;Little-Ihrig, Lynda;Zeleznik, Anthony J.
蛋白激酶A（PKA）信号系统的激活是FSH诱导的颗粒细胞分化所必需的，但PKA的激活是否足以解释该过程中发生的复杂基因表达模式尚不清楚。我们通过用慢病毒载体感染颗粒细胞来解决这个问题，该慢病毒载体指导PKA的组成型活性突变体（PKA-CQR）的表达，并将PKA-CQR的细胞反应与FSH刺激的细胞进行比较。PKA-CQR在未分化的颗粒细胞中的表达导致在cAMP缺乏的情况下诱导雌激素和孕激素的产生。PKA-CQR和FSH对雌激素和孕激素产生的刺激作用被PKA抑制剂H-89抑制，并被PKA选择性cAMP激动剂模拟。FSH和PKA-CQR对P450 SCC和3 β-HSD的mRNA水平的诱导程度相似，而FSH对P450 arom和LHr的mRNA水平的诱导程度更高。基因表达谱的微阵列分析显示，大多数基因似乎是由FSH和PKA-CQR，但有些基因似乎诱导FSH比PKA-CQR在更大程度上。这些结果表明PKA信号通路足以解释大多数基因的诱导（如通过微阵列分析鉴定的），包括颗粒细胞分化期间孕酮生物合成通路的基因。然而，FSH对芳香化酶、LHr和其他基因的最佳诱导似乎需要激活额外的信号通路。
Activation of the protein kinase A (PKA) signaling system is necessary for FSH- induced granulosa cell differentiation, but it is not known whether activation of PKA is sufficient to account for the complex pattern of gene expression that occurs during this process. We addressed this question by infecting granulosa cells with a lentiviral vector that directs the expression of a constitutively active mutant of PKA (PKA-CQR) and compared the cellular responses to PKA-CQR with cells stimulated by FSH. Expression of PKA- CQR in undifferentiated granulosa cells resulted in the induction of both estrogen and progesterone production in the absence of cAMP. The stimulatory effects of both PKA-CQR and FSH on estrogen and progesterone production were suppressed by the PKA inhibitor H-89 and were mimicked by PKA-selective cAMP agonists. mRNA levels for P450scc and 3 beta-HSD were induced to a similar extent by FSH and PKA-CQR, whereas mRNA levels for P450arom and the LHr were induced to a greater extent by FSH. Microarray analysis of gene expression profiles revealed that the majority of genes appeared to be comparably regulated by FSH and PKA-CQR but that some genes appear to be induced to a greater extent by FSH than by PKA-CQR. These results indicate that the PKA signaling pathway is sufficient to account for the induction of most genes (as identified by microarray analysis), including those of the progesterone biosynthetic pathway during granulosa cell differentiation. However, optimal induction of aromatase, the LHr, and other genes by FSH appears to require activation of additional signaling pathways.