Differential Regulation of Glucocorticoid Synthesis in Murine Intestinal EpithelialVersusAdrenocortical Cell Lines

Abstract

Glucocorticoids are steroid hormones with important functions in development, immune regulation, and glucose metabolism. The adrenal glands are the predominant source of glucocorticoids; however, there is increasing evidence for extraadrenal glucocorticoid synthesis in thymus, brain, skin, and vascular endothelium. We recently identified intestinal epithelial cells as an important source of glucocorticoids, which regulate the activation of local intestinal immune cells. The molecular regulation of intestinal glucocorticoid synthesis is currently unexplored. In this study we investigated the transcriptional regulation of the steroidogenic enzymes P450 side-chain cleavage enzyme and 11beta-hydroxylase, and the production of corticosterone in the murine intestinal epithelial cell line mICcl2 and compared it with that in the adrenocortical cell line Y1. Surprisingly, we observed a reciprocal stimulation pattern in these two cell lines. Elevation of intracellular cAMP induced the expression of steroidogenic enzymes in Y1 cells, whereas it inhibited steroidogenesis in mICcl2 cells. In contrast, phorbol ester induced steroidogenic enzymes in intestinal epithelial cells, which was synergistically enhanced upon transfection of cells with the nuclear receptors steroidogenic factor-1 (NR5A1) and liver receptor homolog-1 (NR5A2). Finally, we observed that basal and liver receptor homolog-1/phorbol ester-induced expression of steroidogenic enzymes in mICcl2 cells was inhibited by the antagonistic nuclear receptor small heterodimer partner. We conclude that the molecular basis of glucocorticoid synthesis in intestinal epithelial cells is distinct from that in adrenal cells, most likely representing an adaptation to the local environment and different requirements.

Shifting the feeding of mice to the rest phase creates metabolic alterations, which, on their own, shift the peripheral circadian clocks by 12 hours

“…However, the mechanism involved in this RF extra-corticosterone production has not been elucidated. As cAMP-PKA-CREB signaling plays, at ZT12, a critical role in physiological corticosterone production through transactivation of the numerous genes involved in corticosterone synthesis (22,23), we investigated the role of CREB in extra-corticosterone production. We found, on RF1 night (Fig.…”

Colon cancer cells produce immunoregulatory glucocorticoids

“…LRH-1 overexpression is sufficient to induce steroidogenic enzyme expression in CRC cell lines Regulation of steroid synthesis in the adrenal glands differs substantially from that in the intestine (Mueller et al, 2007). The expression of the steroidproducing enzyme machinery and the synthesis of cortisol in the adrenals are highly dependent on the nuclear factor steroidogenic factor-1 (SF-1, NR5A1; Parker et al, 2002).…”

“…However, different reports indicate that GC synthesis is not restricted to the adrenal glands but may also occur at other sites of the body (Noti et al, 2009), for example, the thymus (Vacchio et al, 1994), the brain (MacKenzie et al, 2000;Davies and MacKenzie, 2003) and the vascular endothelium (Takeda et al, 1994). Recently, we have characterized the intestinal epithelium as a major source of immunoregulatory GC (Cima et al, 2004;Mueller et al, 2006Mueller et al, , 2007Atanasov et al, 2008). In mice, intestinal GC synthesis is highly regulated and is induced upon activation of immune cells.…”

“…In the intestine, steroidogenesis is critically regulated by the nuclear receptor and transcription factor liver receptor homolog-1 (LRH-1, NR5A2; Mueller et al, 2006Mueller et al, , 2007Coste et al, 2007). Consequently, absence of LRH-1 results in strongly reduced intestinal GC synthesis (Mueller et al, 2006) and enhanced susceptibility to intestinal inflammatory processes (Coste et al, 2007).…”

Thiazolide-induced apoptosis in colorectal cancer cells is mediated via the Jun kinase–Bim axis and reveals glutathione-S-transferase P1 as Achilles’ heel

“…In some experiments, cells were preincubated with 2 mM JNK V Inhibitor or DMSO for 30 min. After 8 h of stimulation, cells were lysed, and b-galactosidase and luciferase activity were measured as described previously (Mueller et al, 2007).…”