The unexpected co-occurrence of GRN and MAPT p.A152T in Basque families: Clinical and pathological characteristics

Background: The co-occurrence of the c.709-1G>A GRN mutation and the p.A152T MAPT variant has been identified in 18 Basque families affected by frontotemporal dementia (FTD). We aimed to investigate the influence of the p.A152T MAPT variant on the clinical and neuropathological features of these Basque GRN families. Methods and findings: We compared clinical characteristics of 14 patients who carried the c.709-1G>A GRN mutation (GRN+/A152T-) with 21 patients who carried both the c.709-1G>A GRN mutation and the p.A152T MAPT variant (GRN+/A152T+). Neuropsychological data (n = 17) and plasma progranulin levels (n = 23) were compared between groups, and 7 subjects underwent neuropathological studies. We genotyped six short tandem repeat markers in the two largest families. By the analysis of linkage disequilibrium decay in the haplotype block we estimated the time when the first ancestor to carry both genetic variants emerged. GRN+/A152T+ and GRN+/A152T- patients shared similar clinical and neuropsychological features and plasma progranulin levels. All were diagnosed with an FTD disorder, including behavioral variant FTD or non fluent / agrammatic variant primary progressive aphasia, and shared a similar pattern of neuropsychological deficits, predominantly in executive function, memory, and language. All seven participants with available brain autopsies (6 GRN+/A152T+, 1 GRN+/A152T-) showed frontotemporal lobar degeneration with TDP-43 inclusions (type A classification), which is characteristic of GRN carriers. Additionally, all seven showed mild to moderate tau inclusion burden: five cases lacked β-amyloid pathology and two cases had Alzheimer’s pathology. The co-occurrence of both genes within one individual is recent, with the birth of the first GRN+/A152T+ individual estimated to be within the last 50 generations (95% probability). Conclusions: In our sample, the p.A152T MAPT variant does not appear to show a discernible influence on the clinical phenotype of GRN carriers. Whether p.A152T confers a greater than expected propensity for tau pathology in these GRN carriers remains an open question

Caffeine intake exerts dual genome-wide effects on hippocampal metabolism and learning-dependent transcription

Caffeine is the most consumed psychoactive substance worldwide. Strikingly, molecular pathways engaged by its regular consumption remain unclear. We herein addressed the mechanisms associated with habitual (chronic) caffeine consumption in the mouse hippocampus using untargeted orthogonal-omics techniques. Our results revealed that chronic caffeine exerts concerted pleiotropic effects in the hippocampus, at the epigenomic, proteomic and metabolomic levels. Caffeine lowers metabolic-related processes in the bulk tissue, while it induces neuronal-specific epigenetic changes at synaptic transmission/plasticity-related genes and increased experience-driven transcriptional activity. Altogether, these findings suggest that regular caffeine intake improves the signal-to-noise ratio during information encoding, in part through a fine-tuning of metabolic genes while boosting the salience of information processing during learning in neuronal circuits.This work was supported by grants from Hauts-de-France (PARTEN-AIRR, COGNADORA; START-AIRR, INS-SPECT) and Programs d’Investissements d’Avenir LabEx (excellence laboratory) DISTALZ (Development of Innovative Strategies for a Transdisciplinary approach to ALZheimer’s disease) and EGID (European Genomic Institute for Diabetes ANR-10LABX-46). Our laboratories are also supported by ANR (GRAND to LB, ADORATAU, ADORASTrAU, METABOTAU to DB and BETAPLASTICITY to JSA), COEN (5008), Fondation pour la Recherche Médicale, France Alzheimer/Fondation de France, FHU VasCog research network (Lille, France), Fondation Vaincre Alzheimer (ADOMEMOTAU), European Foundation for the Study of Diabetes (EFSD to JSA), Fondation Plan Alzheimer as well as Inserm, CNRS, Université Lille, Lille Métropole Communauté Urbaine, DN2M. KC hold a doctoral grant from Lille University. VG-M was supported by Fondation pour la Recherche Médicale (SPF20160936000). CM was supported by Région Hauts753 30 754 de-France. ALB is supported by CNRS, Unistra (Strasbourg, France), ANR-16-CE92-0031 755 756 757 758 759 760 761 762 (EPIFUS), ANR-18-CE16-0008-02 (ADORASTrAU), Alsace Alzheimer 67, France Alzheimer (AAP SM 2017 #1664). IP is supported by Fondation pour la Recherche Médicale (SPF201909009162). CEM is grateful for the support by the Alzheimer Forschung Initiative e.V. (AFI, Düsseldorf, Germany). LC was funded by SIF Italian Society of Pharmacology. RAC was supported by LaCaixa Foundation (LCF/PR/HP17/52190001) and FCT (POCI-01-0145-FEDER-03127). Santa Casa da Misericórdia (MB-7-2018) and CEECIND/01497/2017 to LVL