ReviewDNA methylation is not involved in specific down-regulation of HSD3B2, NR4A1 and RARB genes in androgen-secreting cells of human adrenal cortex

- RARB is not associated with the ZR-specific downregulation of HSD3B2 in human adrenal zonation.
- HSD3B2 gene expression in human ZR cells would not be directly mediated by DNA methylation.
- DNA methylation is not involved in zone-specific downregulation of human adrenal NR4A1.
- DNA methylation is not involved in RARB and NR4A1 downregulation in childhood virilising adrenocortical tumors.

We hypothesized that DNA methylation is involved in human adrenal functional zonation. mRNAs expression and methylation pattern of RARB, NR4A1 and HSD3B2 genes in human adrenal tissues (HAT) and in pediatric virilizing adrenocortical tumors (VAT) were analyzed. For analysis of the results samples were divided into 3 age groups according to FeZ involution, pre and post-adrenarche ages. In all HAT, similar RARB mRNA was found including microdissected zona reticularis (ZR) and zona fasciculata, but HSD3B2 and NR4A1 mRNAs were lower in ZR (p < 0.05). NR4A1 and RARB promoters remained unmethylated in HAT and VAT. No adrenal zone-specific differences in NR4A1 methylation were observed.In summary, RARB was not associated with ZR-specific downregulation of HSD3B2 in postnatal human adrenocotical zonation. DNA methylation would not be involved in NR4A1 adrenocortical cell-type specific downregulation. Lack of CpG islands in HSD3B2 suggested that HSD3B2 ZR-specific downregulation would not be directly mediated by DNA methylation.