Integrative multiomic analysis unveils the molecular nexus of mitochondrial dysfunction in the pathogenesis of age-related macular degeneration

Mitochondrial dysfunction is linked to age-related macular degeneration (AMD), but its mechanisms and related molecular networks remain unclear. We explored the association between mitochondrial-related genes and AMD by integrating multiomic data. We acquired summary-level data on mitochondrial-related protein abundance, gene expression, and gene methylation from quantitative trait locus studies. Genetic associations with AMD were sourced from the International Age-related Macular Degeneration Genomics Consortium (discovery), FinnGen (replication), and UK Biobank (replication) studies. We used summary-data-based Mendelian randomization to assess the correlations between mitochondrial-related gene molecular characteristics and AMD. Furthermore, colocalization analysis was performed to ascertain if the detected signal pairings had a common causative genetic variation. Mitochondrial-related gene NFKB1 demonstrated a protective role in AMD (tier 1 evidence), whereas HSPA1A and HSPA1B genes were also associated with decreased AMD risk (tier 2 evidence). The methylation of cg09390974 and cg15409712 in NFKB1 was associated with increased NFKB1 expression, consistent with the protective effect on AMD risk, whereas inverse associations were observed between gene methylation and gene expression for HSPA1B (cg04835051 and cg16372051), supporting the risk roles of methylation in AMD. At circulating protein level, genetically predicted higher levels of HSPA1A (odds ratio [OR] 0.28, 95% confidence interval [CI] 0.19−0.41, P < 0.001), HSPA1B (OR 0.13, 95% CI 0.06−0.27, P < 0.001), and NFKB1 (OR 0.43, 95% CI 0.27−0.68, P < 0.001) were inversely associated with AMD risk. These associations were corroborated in the colocalization analysis. We identified AMD-linked mitochondrial-related genes, potentially improving the understanding of its pathophysiological mechanisms and aiding the identification of novel pharmaceutical targets.