Sex difference in EGFR pathways in mouse kidney-potential impact on the immune system.

BACKGROUND: Epidermal growth factor receptor (Egfr) has been the target of several drugs for cancers. The potential gender differences in genes in the Egfr axis have been suggested in humans and in animal models. Female and male mice from the same recombinant inbred (RI) strain have the same genomic components except the sex difference. A population of different RI mouse strains allows to conduct precise analysis of molecular pathways and regulation of Egfr between female and male mice.

METHODS: The whole genome expression profiles of 70 genetically diverse RI strains of mice were used to compare three major molecular aspects of Egfr gene: the relative expression levels, gene network and expression quantitative trait loci (eQTL) that regulate the expression of Egfr between female and male mice.

RESULTS: Our data showed that there is a significant sex difference in the expression levels in kidney. A considerable number of genes in the gene network of Egfr are sex differentially expressed. The expression levels of Egfr in mice are statistical significant different between C57BL/6 J (B6) and DBA/2 J (D2) genotypes in male while no difference in female mice. The eQTLs that regulate the expression levels of Egfr between female and male mice are also different. Furthermore, the differential expression levels of Egfr showed significantly different correlations with two known biological traits between male and female mice.

CONCLUSION: Overall there is a substantial sex difference in the Egfr pathways in mice. These data may have significant impact on drug target design, development, formulation, and dosage determinant for women and men in clinical trials.