Molecular evidence for a link between the N363S glucocorticoid receptor polymorphism and altered gene expression.

CONTEXT

A single-nucleotide polymorphism (SNP) in the human glucocorticoid receptor (hGR) N363S (rs6195) has been the focus of several clinical studies, and some epidemiological data link this SNP to increased glucocorticoid sensitivity, coronary artery disease, and increased body mass index. However, molecular studies in vitro using reporter gene expression systems have failed, for the most part, to define a link between this polymorphism and altered glucocorticoid receptor function.

OBJECTIVE

The objective of this study was to address the biological relevancy of N363S SNP in GR function by establishing stable U-2 OS (human osteosarcoma) cell lines expressing wild-type hGR or N363S and examining these receptors under a variety of conditions that probe for GR activity including human gene microarray analysis.

DESIGN

Functional assays with reporter gene systems, Western blotting, and human microarray analysis were used to evaluate the activity of wild-type and N363S GR in both transiently and stably expressing cells. In addition, quantitative RT-PCR was used to confirm the microarray analysis.

RESULTS

Functional assays with reporter gene systems and homologous down-regulation revealed only minor differences between the wild-type hGR and N363S receptors in both transiently and stably expressing cell lines. However, examination of the two receptors by human gene microarray analysis revealed a unique gene expression profile for N363S.

CONCLUSIONS

These studies demonstrate that the N363S SNP regulates a novel set of genes with several of the regulated genes supporting a potential role for this GR polymorphism in human diseases.