Biology subjects

Ventoso, I.

Publications and source records attributed to Ventoso, I..

7 recordsLinked to original sources

bioRxiv2026

RiboCollSensor: a sensitive real-time detector of ribosome collisions in mammalian cells based on split-NanoLuc complementation

Disruption of ribosome flux on translating mRNAs can result in ribosome collisions that activate key cellular responses. Despite growing interest in the field, current methods to detect ribosome collisions have limited sensitivity and are not suitable for use in living cells. Here, we describe a novel, reliable, and highly sensitive method based on split-nanoluciferase complementation to detect ribosome collisions in living cells. RiboCollSensor relies on the specific recruitment of EDF1-LgBiT to collided ribosomes near uS4-SmBiT, which generates luminescence due to the proximity of the partners in the ribosome. This biosensor showed unprecedented sensitivity, allowing detection of basal ribosome collisions in unstressed cells or under very low stress levels, enabling real-time analysis of collision kinetics. Thus, an increase in collisions could be detected within the first minute after translation disturbance, confirming the role of ribosomal flux as a rapid sensor of cell stress. Ribosome collisions rapidly disappeared after stress withdrawal, whereas under persistent stress, recovery was slower, taking up to two hours depending on the cell type. The ease and flexibility of this method, which requires only transient co-expression of sensor partners in target cells, make it applicable across many cell types to monitor the impact of internal and external cues on ribosome dynamics in real time.

molecular biology↗

bioRxiv2026

The accumulation of orphan ribosomal proteins is a hallmark of ALS

Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disease of poor prognosis, for which age is the strongest risk factor. Despite significant progress in the discovery of ALS-associated mutations, no model explains how such a diversity of mutations converges in a common pathology. In addition, most ALS cases are sporadic and lack known genetic drivers. We recently reported that arginine-rich peptides arising from the C9ORF72 mutation trigger a widespread accumulation of orphan ribosomal proteins (oRP). Here, we show that oRP accumulation is also observed upon expression of other RNA-related ALS mutations, such as hnRNPA2D290V and TDP-43A315T, as well as upon exposure to the ALS-related neurotoxin {beta}-N-methylamino-L-alanine (BMAA). Furthermore, the transcriptional signature of patients with sporadic ALS resembles that of Diamond-Blackfan anemia (DBA), a known ribosomopathy. Supporting the usefulness of our in vitro data, a transcriptional signature defined from these models provides diagnostic and prognostic value in ALS patients. We propose that the accumulation of oRPs due to dysfunctional ribosome biogenesis is a molecular hallmark of ALS that can contribute to the progressive loss of motor neurons in the disease.

neuroscience↗

bioRxiv2026

A chemical inducer of ribophagy limits the toxicity of ALS-related arginine-rich peptides

C9ORF72 intronic repeat expansions are the most frequent mutation found in Amyotrophic Lateral Sclerosis (ALS), producing toxic arginine-rich dipeptides (DPR) that disrupt RNA metabolism and trigger the accumulation of orphan ribosomal proteins (RP). Through a large phenotypic chemical screen, we identified "SALSa", a novel compound that mitigates DPR toxicity. Mechanistically, SALSa acts as a chemical inducer of ribophagy, a specialized form of autophagy that promotes RP clearance. Interestingly, this effect is unrelated to mTOR inhibition, the main regulator of autophagy. In contrast, this is due to an effect of the drug in ribosome biogenesis, which triggers a protective response to clear defective ribosomes. Accordingly, SALSa accumulates in nucleoli and perturbs the final steps of rRNA maturation. SALSa reduces DPR toxicity in differentiated neurons and significantly extends lifespan in a Drosophila melanogaster model of C9ORF72 ALS. These findings suggest that stimulating ribophagy could be beneficial for pathologies associated to dysfunctional ribosome biogenesis, including C9ORF72 ALS.

molecular biology↗

bioRxiv2024

The differential effect of SARS-COV-2 NSP1 on mRNA translation and stability reveals new insights linking ribosome recruitment, codon usage and virus evolution

The non-structural protein 1 (NSP1) of SARS-CoV-2 blocks the mRNA entry channel of the 40S ribosomal subunit, causing inhibition of translation initiation and subsequent degradation of host mRNAs. However, target mRNA specificity and the way in which viral mRNAs escape NSP1-mediated degradation have not been clarified to date. Here we found that NSP1 acts as a translational switch capable of blocking or enhancing translation depending on how preinitiation complex 43S-PIC is recruited to the mRNA, whereas NSP1-mediated mRNA degradation mostly depends on codon usage bias. Thus, fast-translating mRNAs with optimal codon usage for human cells that preferentially recruit 43S-PIC by threading, showed a dramatic sensitivity to NSP1. On the contrary, slow-translating mRNAs with suboptimal codon usage and 5 UTR that enabled slotting on 43S-PIC were resistant to or even enhanced by NSP1. Translation of SARS-CoV-2 mRNAs escapes NSP1-mediated inhibition by a proper combination of suboptimal codon usage and slotting-prone 5 UTR that also confers efficient translation. Thus, the prevalence of non-optimal codons found in SARS-CoV-2 and other coronavirus genomes is favored by the distinctive effect that NSP1 plays on translation and mRNA stability.

molecular biology↗

bioRxiv2023

Nucleolar stress caused by arginine-rich peptides triggers a ribosomopathy and accelerates ageing in mice

Nucleolar stress (NS) has been associated to several age-related diseases such as cancer or neurodegeneration. To investigate the mechanisms of toxicity triggered by NS, we here used (PR)n arginine-rich peptides that are found in patients of some neurodegenerative diseases. Although these peptides accumulate at nucleoli and generate NS, how this translates into cellular toxicity is poorly understood. We here reveal that whereas (PR)n expression leads to an overall decrease in protein abundance, this occurs concomitant with an accumulation of free ribosomal (r) proteins in the cytoplasm, a hallmark of ribosomopathies. Conversely, cells with acquired resistance to (PR)n peptides present global downregulation of r-proteins and low levels of mTOR signaling. In mice, systemic expression of (PR)97 drives widespread NS and accelerated ageing, which is associated to an increased expression of r-proteins and mTOR hyperactivation. Furthermore, the reduced lifespan of (PR)97-expressing mice was alleviated by the mTOR inhibitor rapamycin. Importantly, we show that the generalised accumulation of free r-proteins is a common outcome in response to chemical or genetic perturbations that trigger NS, such as Actinomycin D, TIF-IA depletion, or the expression of mutant HMGB1 variants recently associated to rare human diseases. Together, our study presents in vivo evidence supporting the role of NS as a driver of ageing, and provides a general framework to explain the toxicity caused by NS in mammalian cells.

molecular biology↗

bioRxiv2021

Progressive alterations of striatal polysomal architecture in a mouse model of Huntington's disease

Given their highly polarized morphology and functional singularity, neurons require precise spatial and temporal control of protein synthesis. Alterations in protein translation have been implicated in the development and progression of a wide range of neurological and neurodegenerative disorders, including Huntingtons disease (HD). In this study we examined the architecture of polysomes in their native brain context in striatal tissue from the zQ175 knock-in mouse model of HD. We performed 3D electron tomography of high-pressure frozen and freeze-substituted striatal tissue from HD models and corresponding controls at different ages. Electron tomography results revealed progressive remodelling towards a more compacted polysomal architecture in the mouse model, an effect that coincided with the emergence and progression of HD related symptoms. The aberrant polysomal architecture is compatible with ribosome stalling phenomena. In fact, we also detected in the zQ175 model an increase in the striatal expression of the stalling relief factor EIF5A2 and an increase in the accumulation of eIF5A1, eIF5A2 and hypusinated eIF5A1, the active form of eIF5A1. Polysomal sedimentation gradients showed differences in the relative accumulation of 40S ribosomal subunits and in polysomal distribution in striatal samples of the zQ175 model. These findings indicate that changes in the architecture of the protein synthesis machinery may underlie translational alterations associated with HD, opening new avenues for understanding the progression of the disease.

neuroscience↗

bioRxiv2018

DNA and RNA binding mediate the toxicity of arginine-rich peptides encoded by C9ORF72 GGGGCC repeats

Due to their capability to transport chemicals or proteins into target cells, cell-penetrating peptides (CPPs) are being developed as therapy delivery tools. However, and despite their interesting properties, arginine-rich CPPs often show toxicity for reasons that remain poorly understood. Using a (PR)n dipeptide repeat that has been linked to amyotrophic-lateral sclerosis (ALS) as a model of an arginine-rich CPP, we here show that the presence of (PR)n leads to a generalized displacement of RNA- and DNA-binding proteins from chromatin and mRNA. Accordingly, any reaction involving nucleic acids such as RNA transcription, translation, splicing and degradation or DNA replication and repair are impaired by the presence of the CPP. Interestingly, the effects of (PR)n are fully mimicked by PROTAMINE, a small arginine-rich protein that displaces histones from chromatin during spermatogenesis. We propose that widespread coating of nucleic acids and consequent displacement of RNA- and DNA-binding factors from chromatin and mRNA accounts for the toxicity of arginine-rich CPPs, including those that have been recently associated to the onset of ALS.

neuroscience↗