Multi-omics analyses identify potential epigenetic loci associated with survival in amyotrophic lateral sclerosis across diverse populations.

Abstract

Amyotrophic lateral sclerosis (ALS) is a severe motor neuron disease, with highly diverse survival time. However, genetic and epigenetic factors influencing ALS survival across diverse populations remain unclear. We performed whole-genome sequencing (WGS) and DNA methylome array in blood DNA of patients with ALS. For survival analysis, we used Cox proportional hazards model for genetic variants, DNA methylation (DNAm) of CpG sites or CpG-SNPs in Chinese and Canadian cohorts, followed by meta-analysis. We performed pathway enrichment analysis for candidate genes inferred from DNAm events associated with survival. In paired genome and methylome data, we analysed the effect of the candidate CpG-SNP genotypes on DNAm status. Genome-wide cross-population meta-analysis of common variants in 511 patients with ALS showed a suggestive association of CAV1/CAV2 rs117002347 genotypes with survival. Epigenome-wide cross-population meta-analysis in 459 patients revealed that ALS survival was significantly linked to DNAm of 88 CpGs on 40 genes, and highlighted the AMPK and cytoskeleton pathways. Epigenome-wide cross-population meta-analysis of CpG-SNPs in 459 patients identified 8 loci on 4 genes, including BAG6 (cg27014438/rs28732154), which was further validated in another 204 patients with ALS. Moreover, analysis of paired genome/epigenome data (n = 454) indicated that BAG6 rs28732154 genotypes may modulate cg27014438 methylation, which is also a cis-eQTM of BAG6 expression in blood. Our study identified BAG6 cg27014438 methylation as a potential epigenetic modifier of ALS survival. BAG6 cg27014438 methylation is modulated by rs28732154 genotypes, and linked to BAG6 expression. Our findings extended our understanding of epigenetic modifiers in ALS survival. This work was supported by the National Natural Science Foundation of China (82071430, 82371878) (MZ), Shanghai Municipal Natural Science Foundation General Program (22ZR1466400) (MZ), the Fundamental Research Funds for the Central Universities (MZ), the G. Harry Sheppard Memorial Research Fund, and Canadian Consortium on Neurodegeneration in Aging (ER).