Biology subjects

Glaria, I.

Publications and source records attributed to Glaria, I..

4 recordsLinked to original sources

bioRxiv2025

C9orf72 polyGA knock-in mice exhibit mild motor and proteomic changes consistent with ALS/FTD

A GGGGCC repeat expansion in C9orf72 is the most common genetic cause of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). The repeat expansion is translated into five different dipeptide repeat proteins: polyGA, polyGP, polyGR, polyAP and polyPR. To investigate the effect of polyGA, which is the most abundant dipeptide repeat protein in patient brains, we used CRISPR/Cas9 to insert 400 codon-optimized polyGA repeats immediately downstream of the mouse C9orf72 start codon. This generated (GA)400 knock-in mice driven by the endogenous mouse C9orf72 promoter, coupled with heterozygous C9orf72 reduction. (GA)400 mice develop subtle pathology including mild motor dysfunction characterized by impaired rotarod performance. Quantitative proteomics revealed polyGA expression caused protein alterations in the spinal cord, including changes in previously identified polyGA interactors. Our findings show that (GA)400 mice are a complementary in vivo model to better understand C9ALS/FTD pathology and determine the specific role of single DPRs in disease.

neuroscience↗

bioRxiv2024

The whole genome analysis of four Orf virus strains from Europe and South America.

Orf virus (ORFV) is the etiological agent of Contagious Ecthyma (CE), a worldwide disease that mainly affects sheep, goats, wild ruminants, and humans. Here, we determined the complete genome sequence of two ORFV strains from Spain (NAV and ARA) and two from Argentina (HRE and CHB), representing the second report from Europe and the first from South America. The assembled genomes of the ARA, CHB, HRE, and NAV strains of ORFV were found to be 137,891 bp, 137,160 bp, 137,340 bp, and 137,214 bp long, respectively, containing 132 genes in each strain, showing high amino acid identity and similar lengths to the reference strain NZ2. We performed a microsatellite analysis to determine a molecular signature for strains that differ in their host (sheep or goat). In addition, the analysis of 32 specially selected genes showed that the nucleotide substitution rate for this dataset was 3.2x10-5 subs/site/year (95% HPD 4.2X10-8 -7.6 X10-5) with a median value of 2.8 x 10-5 subs/site/year, placing the TMRCA (median divergence time) in 1661. The genetic characterization of ORFV strains not only allows epidemiological studies but is the first step toward the development of molecular tools oriented to diagnostics and vaccines.

microbiology↗

bioRxiv2023

PolyGR and polyPR knock-in mice reveal a conserved neuroprotective extracellular matrix signature in C9orf72 ALS/FTD neurons

A GGGGCC repeat expansion in C9orf72 is the most common genetic cause of ALS and FTD (C9ALS/FTD). The presence of dipeptide repeat (DPR) proteins, generated by translation of the expanded repeat, is a major pathogenic feature of C9ALS/FTD pathology, but their most relevant effects in a physiological context are not known. Here, we generated C9orf72 DPR knock-in mouse models characterised by physiological expression of 400 codon-optimised polyGR or polyPR repeats, and heterozygous C9orf72 reduction. (GR)400 and (PR)400 knock-in mice exhibit cortical neuronal hyperexcitability, age-dependent spinal motor neuron loss and progressive motor dysfunction, showing that they recapitulate key features of C9FTD/ALS. Quantitative proteomics revealed an increase in extracellular matrix (ECM) proteins in (GR)400 and (PR)400 spinal cord, with the collagen COL6A1 the most increased protein. This signature of increased ECM proteins was also present in C9ALS patient iPSC-motor neurons indicating it is a conserved feature of C9ALS/FTD. TGF-{beta}1 was one of the top predicted regulators of this ECM signature and polyGR expression in human iPSC-neurons was sufficient to induce TGF-{beta}1 followed by COL6A1, indicating TGF-{beta}1 is one driver of the ECM signature. Knockdown of the TGF-{beta}1 or COL6A1 orthologue in Drosophila dramatically and specifically exacerbated neurodegeneration in polyGR flies, showing that TGF-{beta}1 and COL6A1 protect against polyGR toxicity. Altogether, our physiological C9orf72 DPR knock-in mice have revealed a neuroprotective and conserved ECM signature in C9FTD/ALS.

neuroscience↗

bioRxiv2022

Genome-wide RNA binding analysis of C9orf72 poly(PR) dipeptides

An intronic GGGGCC repeat expansion in C9orf72 is a common genetic cause of amyotrophic lateral sclerosis and frontotemporal dementia. The repeats are transcribed in both sense and antisense directions to generate distinct dipeptide repeat proteins, of which poly(GA), poly(GR) and poly(PR) have been implicated in contributing to neurodegeneration. Poly(PR) binding to RNA may contribute to toxicity, but analysis of poly(PR)-RNA binding on a genome-wide scale has not yet been carried out. We therefore performed crosslinking and immunoprecipitation (CLIP) analysis in human cells to identify the RNA binding sites of poly(PR). We found that poly(PR) binds to nearly 600 RNAs, with the sequence GAAGA enriched at the binding sites. In vitro experiments showed that polyGAAGA RNA binds poly(PR) with higher affinity than control RNA and induces phase-separation of poly(PR) into condensates. These data indicate that poly(PR) preferentially binds to polyGAAGA-containing RNAs, which may have physiological consequences.

neuroscience↗