• Four fully characterised sets of isogenic iPSC lines carrying one of the following APOE genotypes: APOE-Ɛ2/Ɛ2, APOE-Ɛ3/Ɛ3, APOE-Ɛ4/Ɛ4, APOE-Ɛ3/Ɛ4, and APOE-KO have been developed. These cells are available to the scientific community, distributed by the ECACC (
https://www.phe-culturecollections.org.uk(öffnet in neuem Fenster)).
• Existing CSF and blood samples from MCI subjects have been made available to the consortium, and new samples have been collected. CSF samples have been measured using state-of-the-art analytical techniques, focusing on metabolites involved in oxidative and nitrosative stress, as well as inflammation.
• A demonstration of a human blood-brain barrier on-a-chip model. This can be used, for example, to study the effects of different APOE genotypes on barrier function, or how potential therapies are transported into the brain.
• Using existing multi-omics data of EMC, UKK and Janssen, 12 metabolites circulating in blood (11 HDL sub-fractions and the fatty acid DHA) were found to be associated with improved cognitive function and 3 circulating metabolites (glycoprotein acetyls, glutamine and ornithine) with cognitive impairment. Stratified by APOE, we found that in those carrying the APOE*3 and the APOE*4 genotype, the metabolites determine conversion to AD. Findings were validated by external partners.
• We showed that a rare coding variant in the PLCG2 gene slows Alzheimer's disease progression and maintains cognitive function- apparently counteracting the deleterious effect of the APOE ε4 allele. This highlights the PLCG2 enzyme as a potential target for therapeutic intervention in AD.
• Using known AD susceptibility genes, different cognitive composites have been tested to define the best way to operationalize cognitive decline across longitudinal MCI cohorts. This analysis showed that when analysing several heterogeneous cohorts of MCI as in ADAPTED, MMSE has to be considered the most efficient neuropsychological discriminant factor for progression to dementia and rate of cognitive decline. Importantly, this analysis also revealed that a composite assessing memory and executive function detects the effect of ApoE4 more powerfully than the MMSE which assesses additional cognitive domains. This finding suggests that genetic risk factors for AD may exert their effect on specific neuronal networks underlying particular cognitive functions.
• Metabolite analysis revealed that AD patients carrying at least one APOE-ε4 allele showed a dysregulation in omega-3 and omega-6 fatty acid pathways. This dysregulation is not observed in healthy controls stratified similarly to AD patients. These findings are corroborated by Mendelian Randomization, suggesting that the dysregulation is rather a consequence and thus a biomarkers of the disease process rather than a causal effect.
• Lysophosphatidic acids (LPAs) are bioactive signaling phospholipids that have been implicated in Alzheimer’s disease (AD). We show that LPAs may contribute to early AD pathogenesis, and that APOE may influence the association between LPAs and Aβ-42
• Data from many publicly available datasets have been curated and integrated into the ADAPTED TranSMART database and is available for APOE stratified questioning. Three-stage integrative analysis has been carried out and has identified specific immunological signatures for APOE genotypes contributing to the susceptibility to Alzheimer’s disease.
• The database with publicly available datasets has been supplemented with the extensive omics (transcriptomics, metabolomics and proteomics) analysis performed throughout the consortium on human or humanized samples. This data will become available to the broader scientific community following their reporting in scientific journals.