Ana Gámez-Valero, Spain
Health Science Research Institute Germans Trias i Pujols REMAR-IVECAT groupAuthor Of 1 Presentation
MICRO-RNA ALTERATIONS DETECTABLE IN CSF EXTRACELLULAR VESICLES RELATED TO DYSFUNCTION OF AUTOPHAGY PATHWAYS IN 4R-TAUOPATHIES
Abstract
Aims
Our goals were: 1) to identify microRNA alterations in cerebrospinal fluid (CSF) extracellular vesicles (EVs) from patients with frontotemporal disorders; 2) to elucidate the effect of candidate microRNAs on autophagy mechanisms and tau turnover.
Methods
EV-derived microRNA levels from 144 CSF samples (including healthy controls, patients with Alzheimer’s disease (AD) or frontotemporal disorders) were analyzed by qPCR. MicroRNA changes in patients were reproduced in two in-vitro models. Total RNA isolated from SK-N-MC cells quantified by RNA-seq. Neuro-2a cells with inducible expression of human wild-type (WT)-tau or pathogenic P301L-tau were used to measure levels of tau and autophagy-related proteins by immunoblot. Neuro-2a cells expressing fluorescent reporters were used to monitor autophagy dynamics.
Results
MicroRNA profiling in CSF-derived EVs revealed four microRNAs differentially expressed in 4R tau-related pathologies when compared to other phenotypes. Analysis of gene expression profiles upon imposing changes in miR that mimic those found in the patients’ CSF revealed 30 genes differentially expressed for three candidate microRNAs, which point to 17 significantly enriched biological pathways. Quantification of turnover of WT and mutant tau in Neuro-2a cell lines, after treatment with microRNA modulators, suggests that autophagic degradation of tau is impaired when reproducing certain microRNA alterations observed in patients. Autophagy reporter studies also indicate that microRNA changes observed in the patients are inhibitory in some autophagy pathways.
Conclusions
Our results indicate the presence of a characteristic microRNA signature seemingly specific for 4R-tauopathies. Functional studies of these microRNAs in cultured cells showed inhibitory effects on some autophagy pathways and impairment of tau turnover.