Alterations in DNA Methylation, Proteomic, and Metabolomic Profiles in African Ancestry Populations with APOL1 Risk Alleles

Background: The APOL1 high-risk haplotype has been associated with chronic kidney disease (CKD) and the deterioration of kidney function, particularly in populations with West African ancestry. However, the mechanisms by which APOL1 risk variants increase the risk for kidney disease and its progression have not been fully elucidated. Methods: We compared methylation (N = 3,191; 715 [22%] carriers), proteomic (N = 1,240; 169 [14%] carriers), and metabolomic (N = 6,309; 674 [11%] carriers) profiles in African and Hispanic/Latino carriers of two APOL1 high-risk alleles (G1/G1, G2/G2, G1/G2) and non-carriers (G0/G0), excluding heterozygotes (G0/G1, G0/G2), from the PAGE Consortium and UK BioBank. In each study, the associations between the APOL1 high-risk haplotype and up to 722,719 CpG sites, 2,923 proteins, or 836 metabolites were estimated using covariate-adjusted linear regression models, followed by fixed-effects sample size weighted meta-analyses. Results: Significant associations were observed between APOL1 high-risk haplotype and methylation at 52 CpG sites, with 48 located on chromosome 22 and 18 in the vicinity of APOL1 – 4 and MYH9 . All significant CpG sites near APOL2 were hypomethylated, whereas those near APOL3 and APOL4 were hypermethylated. APOL1 -associated CpG sites were also identified in genes involved in ion transport and mitochondrial stress pathways. Sensitivity analyses indicated consistent yet attenuated effects among heterozygotes, supporting an additive effect of APOL1 risk alleles. Further analyses of the 52 CpG sites identified two near APOL4 exhibiting G1-specific effects, eight associated with CKD but none with eGFR, and three showing heterogeneity by CKD status. Additionally, carrying two APOL1 risk alleles was associated with higher plasma APOL1 protein (β = 1.12, P FDR = 2.26e-70) and lower C18:1 cholesteryl ester metabolite (Z = -4.50, P FDR = 4.83e-3). Conclusions: Our results demonstrate differential methylation, proteomic, and metabolomic profiles associated with APOL1 high-risk haplotypes.