Abstract 414: Ath28 Congenic Mice Confirm Atherosclerosis Modifying Gene on the Distal End of Chromosome 2
Objective: Strain intercrosses between apoE-deficient mice on the AKR (athero-resistant) and DBA/2 (athero-sensitive) strains identified the Ath28 quantitative trait locus (QTL) on the distal end of chromosome 2 (chr 2). We bred congenic mice on the DBA/2 background containing AKR alleles on chr 2 from 172.5 to 180 Mb in order to confirm the presence of atherosclerosis modifying genes in this region. Methods and Results: We used marker assisted backcrossing to generate DBA/2.AKR (chr 2) apoE-deficient congenic mice. High density genotyping using the MegaMuga array revealed that the AKR strain donated DNA on chr 2 from 171.5 Mb to the end of the chromosome, with the most distal marker tested at 180 Mb, while DBA/2 markers were found elsewhere in the genome. Mice heterozygote for the congenic interval were intercrossed to generate progeny homozygous for the AKR allele (AA) or the DBA/2 allele (DD). Female and male mice were fed a chow diet and sacrificed at 16 weeks of age. In the females, there was no effect on body weight; the total cholesterol levels trended 13% lower for the DD vs. AA mice (p=0.07); and, the HDL-C levels were 55% higher for the DD vs. AA mice (p=0.05). Despite having lower total cholesterol levels, the DD mice had 68% larger aortic root lesion areas (p=0.05, N=10 and 14 for AA and DD mice, respectively). In the males, the body weight was 12% higher in the DD vs. AA mice (p<0.01); the total cholesterol levels were similar in the DD and AA mice; and, the HDL-C levels were 73% higher for the DD vs. AA mice (p<0.05). The male DD mice had 27% larger aortic root lesion areas (NS), but we are adding more mice to this study to determine if this is significant (N=6 and 11 for AA and DD mice, respectively). Conclusions: Ath28 congenic mice confirm the presence of an atherosclerosis modifying gene on the distal end of chr 2 in chow-fed females. This interval in chr 2 contains over 100 genes. Our prior identification of missense variants between these strains, as well as transcriptomic and eQTL analyses have identified some candidate genes in this interval including Cstf1, Ctcfl, Zbp1, Ankrd60, Gnas, Cdh4, Ctsz, and Rae1 . Further functional genomic studies and creating mice with smaller congenic intervals will be needed in order to narrow the list of candidate genes for in vivo testing.