TRANSCRIPTOME PROFILING OF THE HUMAN ADRENAL ZONA FASCICULATA AND ZONA RETICULARIS

Presentation Number: SAT-393
Date of Presentation: June 15th, 2013

Juilee Rege*1, Yasuhiro Nakamura2, Tao Wang3, Todd D Merchen4, Hironobu Sasano2 and William E Rainey5
1University of Michigan, Ann Arbor, MI, 2Tohoku University Graduate School of Medicine, Sendai, Japan, 3Medical College of Georgia, Augusta, GA, 4Georgia Regents University, Augusta, GA, 5University of Michigan, MI

Abstract

Introduction: The human adrenal cortex is anatomically and functionally divided into three concentric zones; the zona glomerulosa (ZG), zona fasciculata (ZF) and zona reticularis (ZR). ZG and ZF secrete mineralocorticoids and glucocorticoids respectively, whereas the human ZR is considered the primary site for the production of several 19-carbon steroids often called the adrenal androgens. However, the gene profiles and exact molecular mechanisms leading to the functional phenotype of the ZF and ZR are still not clearly defined. In the present study, we have identified the transcripts that are differentially expressed in the ZF and ZR. Objective: To compare the transcriptome profiles of ZF and ZR. Materials and Methods: ZF and ZR were microdissected from ten human adrenals. Total RNA was extracted from the ten ZF/ZR pairs and hybridized to an Illumina microarray chip to identify the transcript differences. The five most highly expressed transcripts in each zone were selected for confirmation with real time quantitative RT-PCR (qPCR). Immunohistochemistry was also performed on the top four zone-specific genes. Results: Microarray results demonstrated that out of the approximately 40,000 transcripts analyzed, only 691 genes were significantly different in the ZF and ZR. ZF had 193 transcripts with ≥ 2-fold increase compared to its paired ZR, whereas ZR was found to have 152 transcripts with ≥ 2-fold higher expression than in ZF. Microarray and qPCR analysis of transcripts encoding steroidogenic enzymes (N=13) demonstrated that only HSD3B2 (type 2 3beta-hydroxysteroid dehydrogenase) showed higher expression in ZF compared to ZR (P<0.01). In contrast, SULT2A1 (steroid sulfotransferase), AKR1C3 (type 5 17beta-hydroxysteroid dehydrogenase) and CYB5 (cytochrome b5) showed elevated transcript levels in ZR (P<0.01). Immunohistochemistry and qPCR studies confirmed that the ZF had increased expression of LEF1 (lymphoid enhancer-binding factor 1) and NOV (nephroblastoma overexpressed gene) while ZR showed increased expression of FGG (fibrinogen gamma chain) and SLC27A2 (fatty acid transporter, member 2). Conclusion: Microarray is a technique suitable for the comprehensive analysis of gene expression profiles across a panel of tissues. This approach has revealed several novel candidate genes for elucidating the molecular mechanisms governing the ZF and ZR, thereby increasing our understanding of the functional zonation of these two adrenocortical zones.

 

Nothing to Disclose: JR, YN, TW, TDM, HS, WER