Identification of Allergen-Susceptibility Genes Using Recombinant Inbred Mouse Model of Allergic Asthma

Abstract

RATIONALE: Knowledge of genetic determinants conferring susceptibility to allergic asthma (AA) remains limited. Identification of chromosomal regions harboring AA susceptibility loci and utilization of recombinant inbred (RI) murine strains may accelerate the discovery of asthma-associated candidate genes. METHODS: AA-sensitive A/J (A) 4-week old mice were sensitized (days 0 and 3) with PBS + Alum (200 μg/100 μl) or OVA HDM allergen + Alum. Mice were challenged intratracheally with PBS or OVA HDM allergen (150 μg/40 μl) on days 10 and 17, and lungs were harvested 6 hours after the second challenge. Gene expression profiles were generated for control (n=5) and AA-affected (n=5) lung tissues using the 430MOEA (22626 genes) GeneChips and data were analyzed by GCOS1.4-GCRMA-SAM streamline. Genes with a false discovery rate (q<0.05%) and ±4 expression fold change versus control were considered significantly affected by AA and linked to the corresponding genetic markers in the mouse genome. RESULTS: The genomic distribution of 167 AA-associated genes was skewed towards chromosomes 1, 11, and 7 which were represented by 12.6%, 12.0% and 8.4% of the allergen challenge-induced genes, respectively. Genomes of 24 available recombinant inbred (RI) backcrosses of A and AA-resistant C57BL/6J (B) strains (AxB) were screened for global parental genetic contributions. This analysis identified the highest content of susceptible A parental genetic markers in AxB-7 (66%) and AxB-9 (62%), suggesting high sensitivity of these strains to allergen challenge. CONCLUSIONS: Bioinformatical identification of allergen sensitive/resistant backcross strains facilitates selection of RI mice for AA phenotyping and will accelerate the discovery of AA susceptibility-associated candidate genes.