Global Profiles of Gene Expression Induced by Adrenocorticotropin in Y1 Mouse Adrenal Cells

Abstract

ACTH regulates the steroidogenic capacity, size, and structural integrity of the adrenal cortex through a series of actions involving changes in gene expression; however, only a limited number of ACTH-regulated genes have been identified, and these only partly account for the global effects of ACTH on the adrenal cortex. In this study, a National Institute on Aging 15K mouse cDNA microarray was used to identify genome-wide changes in gene expression after treatment of Y1 mouse adrenocortical cells with ACTH. ACTH affected the levels of 1275 annotated transcripts, of which 46% were up-regulated. The up-regulated transcripts were enriched for functions associated with steroid biosynthesis and metabolism; the down- regulated transcripts were enriched for functions associated with cell proliferation, nuclear transport and RNA processing, including alternative splicing. A total of 133 different transcripts, i.e. only 10% of the ACTH-affected transcripts, were represented in the categories above; most of these had not been described as ACTH-regulated previously. The contributions of protein kinase A and protein kinase C to these genome-wide effects of ACTH were evaluated in microarray experiments after treatment of Y1 cells and derivative protein kinase A-defective mutants with pharmacological probes of each pathway. Protein kinase A-dependent signaling accounted for 56% of the ACTH effect; protein kinase C-dependent signaling accounted for an additional 6%. These results indicate that ACTH affects the expression profile of Y1 adrenal cells principally through cAMP- and protein kinase A- dependent signaling. The large number of transcripts affected by ACTH anticipates a broader range of actions than previously appreciated.

The Regulated Cell Surface Zymogen Activation of the Proprotein Convertase PC5A Directs the Processing of Its Secretory Substrates

“…The Zymogen Activation of PC5A Is Induced by ACTH-It was previously shown that PC5A mRNA is up-regulated in Y1 cells treated with ACTH or cAMP and that the mRNA levels of other PCs are not modulated by ACTH (34,35). In order to confirm and extend these data to the protein level, the cell surface localization of PC5A in Y1 cells was tested before and after 16-h treatment with either 8-Br-cAMP (Fig.…”

“…It has been reported that furin, PACE4, and PC5A can process pro-ADAMTS-4, resulting in its activation (40). ADAMTS-4 mRNAs are highly up-regulated upon ACTH or cAMP treatments of Y1 cells (35). Therefore, it represented a logical substrate to analyze in our system.…”

Adrenal transcription regulatory genes modulated by angiotensin II and their role in steroidogenesis

“…Several high-throughput gene expression-profiling studies in the adrenal gland have been reported for human fetal and adult adrenal glands (42), adrenocortical tumors (20), normal subjects and patients with ACTH-dependent and -independent macronodular adrenal hyperplasia (9), steroidogenic enzymes in aldosterone-producing adenoma or cortisol-producing adenoma (3), human sporadic adrenocortical tumors (12), adrenocortical adenomas and carcinomas (52), primary pigmented nodular adrenocortical disease samples (24), and ACTH-induced gene expression in Y1 mouse adrenocortical cells (47). However, no study has focused specifically on transcription regulators that can be involved in both normal and abnormal adrenal physiology.…”

Failure of adrenal corticosterone production in POMC-deficient mice results from lack of integrated effects of POMC peptides on multiple factors

“…Regulation of these factors was assessed at the gene or protein level either by adding ACTH to in vitro systems such as primary cell cultures from human, bovine, rat, and mouse adrenals, as well as the Y1 tumor adrenal cell line (10,23,27,28,30,31), or by removing ACTH in vivo through hypophysectomy of rats (16,18,29). The resulting effects demonstrate either the potential of ACTH to regulate a particular factor (in vitro experiments) or the reaction of intact adrenals to the sudden depletion of ACTH (in vivo experiments).…”