Genome-Wide Mendelian Randomization Identifies Ferroptosis-Related Drug Targets for Alzheimer's Disease

Abstract

Background: Alzheimer's disease (AD) currently lacks effective disease-modifying treatments. Recent research suggests that ferroptosis could be a potential therapeutic target. Mendelian randomization (MR) is a widely used method for identifying novel therapeutic targets.

Objective: Employ genetic information to evaluate the causal impact of ferroptosis-related genes on the risk of AD.

Methods: 564 ferroptosis-related genes were obtained from FerrDb. We derived genetic instrumental variables for these genes using four brain quantitative trait loci (QTL) and two blood QTL datasets. Summary-data-based Mendelian randomization (SMR) and two-sample MR methods were applied to estimate the causal effects of ferroptosis-related genes on AD. Using extern transcriptomic datasets and triple-transgenic mouse model of AD (3xTg-AD) to further validate the gene targets identified by the MR analysis.

Results: We identified 17 potential AD risk gene targets from GTEx, 13 from PsychENCODE, and 22 from BrainMeta (SMR p < 0.05 and HEIDI test p > 0.05). Six overlapping ferroptosis-related genes associated with AD were identified, which could serve as potential therapeutic targets (PEX10, CDC25A, EGFR, DLD, LIG3, and TRIB3). Additionally, we further pinpointed risk genes or proteins at the blood tissue and pQTL levels. Notably, EGFR demonstrated significant dysregulation in the extern transcriptomic datasets and 3xTg-AD models.

Conclusions: This study provides genetic evidence supporting the potential therapeutic benefits of targeting the six druggable genes for AD treatment, especially for EGFR (validated by transcriptome and 3xTg-AD), which could be useful for prioritizing AD drug development in the field of ferroptosis.

Keywords: 3xTg-AD; Alzheimer’s disease; Mendelian randomization; ferroptosis.

Fig. 1

The principle and flowchart of MR analysis.

Fig. 2

The Manhattan plots of MR analysis results using QTLs and AD GWAS summary statistics. The gray horizontal line is the Bonferroni corrected significant level. A) The MR result using GTEx brain eQTL as instruments; B) The MR result using PsychENCODE eQTL as instruments; C) The MR result using BrainMeta eQTL as instruments; D) The MR result using ROSMAP pQTL as instruments; E) The MR result using cis-eQTL SNPs from eQTLGen Consortium as genetic instruments; F) The MR result using cis-pQTL SNPs from circulating 4,907 proteins levels as genetic instruments.

Fig. 3

A) SMR method identified six overlapping ferroptosis-related gene targets associated with AD when using GTEx, PsychENCODE, and BrainMeta brain eQTL as genetic instruments, including PEX10, CDC25A, EGFR, DLD, LIG3, and TRIB3. B) Venn diagram showed the intersection of AD risk genes identified by GTEx, PsychENCODE, and BrainMeta brain eQTL and ROSMAP brain pQTL as genetic instruments. C)Venn diagram showed the intersection of AD risk genes identified by GTEx, PsychENCODE, and BrainMeta brain eQTL and eQTLGen blood eQTL as genetic instruments. D) Venn diagram showed the intersection of AD risk genes identified by eQTLGen blood eQTL and blood pQTL as genetic instruments.

Fig. 4

The external transcriptome dataset corroborated the identification of six gene targets through SMR analysis. Notably, EGFR, DLD, PEX10, and LIG3 demonstrated significant expression differences relative to the control group (p < 0.05). Conversely, TRIB3 and CDC25A failed to reach statistical significance.

Fig. 5

Validation of the gene targets by western blotting using 3xTg-AD mice. Both EGFR (p < 0.05) and TRIB3 (p < 0.05) were downregulated in the whole brain tissues compared with the control group. WT, wild type; MOD, model of 3xTg-AD mice.