Angiotensin II (AngII) stimulates adrenocortical cells to produce aldosterone, a master regulator of blood pressure. Despite extensive characterization of the transcriptional and enzymatic control of adrenocortical steroidogenesis, there are still major gaps in the precise regulation of AngII-induced gene expression kinetics. Specifically, we do not know the regulatory contribution of RNA-binding proteins (RBPs) and RNA decay, which can control the timing of stimulus-induced gene expression. To investigate this question, we performed a high-resolution RNA-seq time course of the AngII stimulation response and 4-thiouridine pulse labeling in a steroidogenic human cell line (H295R). We identified twelve temporally distinct gene expression responses that contained mRNA encoding proteins known to be important for various steps of aldosterone production, such as cAMP signaling components and steroidogenic enzymes. AngII response kinetics for many of these mRNAs revealed a coordinated increase in both synthesis and decay. These findings were validated in primary human adrenocortical cells stimulated ex vivo with AngII. Using a candidate screen, we identified a subset of RNA-binding protein and RNA decay factors that activate or repress AngII-stimulated aldosterone production. Among the repressors of aldosterone were BTG2, which promotes deadenylation and global RNA decay. BTG2 was induced in response to AngII stimulation and promoted the repression of mRNAs encoding prosteroidogenic factors indicating the existence of an incoherent feedforward loop controlling aldosterone homeostasis. These data support a model in which coordinated increases in transcription and decay facilitate the major transcriptomic changes required to implement a prosteroidogenic expression program that actively resolves to prevent aldosterone overproduction.

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RNA 结合蛋白调节人类固醇生成细胞中的醛固酮稳态

血管紧张素 II (AngII) 刺激肾上腺皮质细胞产生醛固酮，醛固酮是血压的主要调节剂。尽管对肾上腺皮质类固醇生成的转录和酶促控制进行了广泛的表征，但在 AngII 诱导的基因表达动力学的精确调节方面仍然存在重大差距。具体来说，我们不知道 RNA 结合蛋白 (RBP) 和 RNA 衰变的调节作用，它们可以控制刺激诱导的基因表达的时间。为了研究这个问题，我们对类固醇生成人细胞系 (H295R) 中的 AngII 刺激反应和 4-硫尿苷脉冲标记进行了高分辨率 RNA-seq 时间过程。我们确定了十二个时间上不同的基因表达反应，其中包含已知对醛固酮产生的各个步骤很重要的 mRNA 编码蛋白，例如 cAMP 信号成分和类固醇生成酶。许多这些 mRNA 的 AngII 反应动力学揭示了合成和衰变的协调增加。这些发现在用 AngII 离体刺激的原代人肾上腺皮质细胞中得到验证。使用候选筛选，我们确定了激活或抑制 AngII 刺激的醛固酮生成的 RNA 结合蛋白和 RNA 衰变因子的一个子集。醛固酮的阻遏物包括 BTG2，它促进脱腺苷酸化和整体 RNA 衰变。BTG2 是响应 AngII 刺激而被诱导的，并促进了编码前列腺素生成因子的 mRNA 的抑制，表明存在控制醛固酮稳态的不相干前馈回路。