Biology subjects

Groen, E. J.

Publications and source records attributed to Groen, E. J..

4 recordsLinked to original sources

bioRxiv2025

Translation-specific disruption of Col1a1 expression in multiple models of Spinal Muscular Atrophy can be rescued by Risdiplam.

Spinal muscular atrophy (SMA) is a monogenic neurodegenerative disorder caused by decreased levels of Survival of Motor Neuron (SMN) protein. If left untreated, SMA patients have a poor prognosis, marked by the degeneration of motor neurons, progressive muscle weakness and atrophy. The approval of SMN-restoring therapies that improve symptoms and lifespan in patients with SMA has created emerging, non-neuronal phenotypes and an urgent need for deepening our understanding of disease pathogenesis. Leveraging the knowledge that SMN loss drives alterations in translation, we used multiple tissues from a mouse model of SMA to uncover early translational alterations in key mRNAs and proteins, which act as contributors to pathogenesis and hallmarks of the disease. Among hundreds of differentially translated mRNAs, Col1a1 emerged as a translation-specific manifestation of early defects in the mouse model. These findings were confirmed in fibroblasts derived from patients with varying levels of disease severity. Notably, treatment with SMN-restoring therapies rescued COL1A1 protein levels, particularly in fibroblasts from patients with the most severe forms of the disease. Overall, our study identifies COL1A1 as an indicator of disease severity in SMA, which captures early molecular alterations and respond to SMN-modifying therapies.

molecular biology↗

bioRxiv2024

Patient-specific responses to SMN2 splice-modifying treatments in spinal muscular atrophy fibroblasts

The availability of three therapies for the neuromuscular disease spinal muscular atrophy (SMA) highlights the need to match patients to the optimal treatment. Two of these treatments (nusinersen and risdiplam) target splicing of SMN2, but treatment outcomes vary from patient to patient. An incomplete understanding of the complex interactions between SMA genetics, SMN protein and mRNA levels, and gene-targeting treatments, limits our ability to explain this variability and identify optimal treatment strategies for individual patients. To address this, we analyzed responses to nusinersen and risdiplam in 45 primary fibroblast cell lines. Pre-treatment SMN2-FL, SMN2{Delta}7 mRNA, and SMN protein levels were influenced by SMN2 copy number, age, and sex. After treatment, SMN and mRNA levels were more heterogeneous. In 43% of patients, response to both therapies was similar, but in 57% one treatment led to a significantly higher SMN increase than the other treatment. Younger age, higher SMN2 copy number, and higher SMN levels before treatment predicted better in vitro efficacy. These findings showcase patient-derived fibroblasts as a tool for identifying molecular predictors for personalized treatment.

molecular biology↗

bioRxiv2019

SMN-primed ribosomes modulate the translation of transcripts related to Spinal Muscular Atrophy

The contribution of ribosome heterogeneity and ribosome-associated factors to the molecular control of proteomes in health and disease remains enigmatic. We demonstrate that Survival Motor Neuron (SMN) protein, loss of which causes the neuromuscular disease spinal muscular atrophy (SMA), binds to ribosomes and that this interaction is tissue-dependent. SMN-primed ribosomes are positioned within the first five codons of a set of mRNAs which are enriched in IRES-like sequences in the 5UTR and rare codons at the beginning of their coding sequence. Loss of SMN at early-stages of SMA induces translational defects in vivo, characterized by ribosome depletion in rare codons at the third and fifth position of the coding sequence. These positional defects cause ribosome depletion from mRNAs bound by SMN-primed ribosomes and translational impairment of proteins involved in motor neuron function and stability, including acetylcholinesterase. Thus, SMN plays a crucial role in the regulation of ribosome fluxes along mRNAs which encode proteins relevant to SMA pathogenesis.

neuroscience↗

bioRxiv2017

In vivo translatome profiling reveals early defects in ribosome biology underlying SMA pathogenesis

BackgroundGenetic alterations impacting on ubiquitously expressed proteins involved in mRNA metabolism often result in neurodegenerative conditions, with increasing evidence suggesting that translational defects can contribute to disease. Spinal Muscular Atrophy (SMA) is a neuromuscular disease caused by low levels of SMN protein, whose role in disease pathogenesis remains unclear.\n\nResultsBy determining in parallel the in vivo transcriptome and translatome in SMA mice we identified a robust decrease in translational efficiency, arising during early stages of disease. Translational defects affected translation-related transcripts, were cell autonomous, and were fully rescued after treatment with antisense oligonucleotides to restore SMN levels. Defects in translation were accompanied by a decrease in the number of ribosomes in motor neurons in vivo.\n\nConclusionOur findings suggest that neuronal tissues and cells are particularly sensitive to perturbations in translation during SMA, and identify ribosome biology as an important, yet largely neglected, factor in motor neuron degeneration.

neuroscience↗