Journal of Steroid Biochemistry & Molecular Biology 114 (2009) 135–143 Contents lists available at ScienceDirect Journal of Steroid Biochemistry and Molecular Biology journal homepage: www.elsevier.com/locate/jsbmb Genome-wide analysis of DHEA- and DHT-induced gene expression in mouse hypothalamus and hippocampus Qianxing Mo a,1,2 , Shifang Lu a,1 , Carrie Garippa a , Michael J. Brownstein b , Neal G. Simon a,∗ a Dept. of Biological Sciences, Lehigh University, Bethlehem, PA 18015, United States b National Institute of Mental Health, Rockville, MD 20850, United States article info Article history: Received 10 June 2008 Received in revised form 7 January 2009 Accepted 11 January 2009 Keywords: Dehydroepiandrosterone (DHEA) Androgen receptor Genomics CNS Mechanism of action abstract Dehydroepiandrosterone (DHEA) is the most abundant steroid in humans and a multi-functional neu- roactive steroid that has been implicated in a variety of biological effects in both the periphery and central nervous system. Mechanistic studies of DHEA in the periphery have emphasized its role as a prohormone and those in the brain have focused on effects exerted at cell surface receptors. Recent results demon- strated that DHEA is intrinsically androgenic. It competes with DHT for binding to androgen receptor (AR), induces AR-regulated reporter gene expression in vitro, and exogenous DHEA administration regulates gene expression in peripheral androgen-dependent tissues and LnCAP prostate cancer cells, indicating genomic effects and adding a level of complexity to functional models. The absence of information about the effect of DHEA on gene expression in the CNS is a significant gap in light of continuing clinical interest in the compound as a hormone replacement therapy in older individuals, patients with adrenal insufficiency, and as a treatment that improves sense of well-being, increases libido, relieves depressive symptoms, and serves as a neuroprotective agent. In the present study, ovariectomized CF-1 female mice, an established model for assessing CNS effects of androgens, were treated with DHEA (1mg/day), dihydrotestosterone (DHT, a potent androgen used as a positive control; 0.1mg/day) or vehicle (negative control) for 7 days. The effects of DHEA on gene expression were assessed in two regions of the CNS that are enriched in AR, hypothalamus and hippocampus, using DNA microarray, real-time RT-PCR, and immunohistochemistry. RIA of serum samples assessed treatment effects on circulating levels of major steroids. In hypothalamus, DHEA and DHT significantly up-regulated the gene expression of hypocretin (Hcrt; also called orexin), pro-melanin-concentrating hormone (Pmch), and protein kinase C delta (Prkcd), and down-regulated the expression of deleted in bladder cancer chromosome region candidate 1 (Dbccr1) and chitinase 3-like 3 (Chi3l3). Two-step real-time RT-PCR confirmed changes in the expression of three genes (Pmch, Hcrt and Prkcd) using the same RNA sample employed in the microarray experiment. Immunohistochem- istry showed augmentation of prepro-hypocretin (pHcrt) neuropeptide protein expression by DHEA and DHT in hypothalamus, consistent with the localization of orexin neurons. In hippocampus, DHT down- regulated the expression of Prkcd, while DHEA did not have significant effects. RIA results supported the view that DHEA-induced effects were mediated through AR. The current study identified neurogenomic effects of DHEA treatment on a subset of genes directly implicated in the regulation of appetite, energy utilization, alertness, apoptosis, and cell survival. These changes in gene expression in the CNS represent a constellation of effects that may help explain the diverse benefits attributed to replacement therapy with DHEA. The data also provide a new level of detail regarding the genomic mechanism of action of DHEA in the CNS and strongly support a central role for the androgen receptor in the production of these effects. More broadly, the results may be clinically significant because they provide new insights into processes that appear to mediate the diverse CNS effects attributed to DHEA. © 2009 Elsevier Ltd. All rights reserved. Abbreviations: Adione, androstenedione; AR, androgen receptor; B2m, beta-2 microglobulin gene; Chi3l3, chitinase 3-like 3 gene; CNS, central nervous system; CT, threshold cycle; Dbccr1, deleted in bladder cancer chromosomal region candidate 1; DHEA, dehydroepiandrosterone; DHEAS, dehydroepiandrosterone sulfate; DHT, dihydrotestos- terone; FDR, false discovery rate; Hcrt, hypocretin, orexin; IHC, immunohistochemistry; IPD, integrated particle density; MCH, melanin-concentrating hormone; MCHR1, melanin-concentrating hormone receptor 1; OVX, ovarietomized; pHcrt, prepro-hypocretin neuropeptide; Pmch, melanin-concentrating hormone gene; Prkcd, protein kinase C delta gene; REV, relative expression value; T, testosterone. E-mail address: ngs0@lehigh.edu (N.G. Simon). 1 These authors contributed equally to the paper and should be considered co-first authors. 2 Current address: Department of Epidemiology and Biostatistics, Memorial Sloan Kettering Cancer Center, New York, NY 10021, United States. 0960-0760/$ – see front matter © 2009 Elsevier Ltd. All rights reserved. doi:10.1016/j.jsbmb.2009.01.015