Biology subjects

Levesque, A.

Publications and source records attributed to Levesque, A..

3 recordsLinked to original sources

bioRxiv2026

c-MAF transduces motor neuron firing to sustain fast-glycolytic myofibers and neuromuscular junctions

This study examined how motoneuron activity influences transcription factor binding in mouse fast glycolytic Myh4+ muscle fibers. Single nucleus multiomics of innervated versus denervated tibialis anterior muscles revealed altered chromatin accessibility: SIX and c-MAF binding sites decreased while JUN, FOS, and RUNX1 sites increased in denervated Myh4+ myonuclei. c-MAF showed strong nuclear enrichment after 100 Hz stimulation and periods of increased motoneuron activity but was absent following denervation, establishing it as a primary readout of fast motoneuron firing. Genome-wide analysis demonstrated that c-MAF binding site spacing encodes functionally distinct muscle gene programs. Analysis of constitutive and inducible skeletal muscle-specific c-Maf mutants revealed that c-MAF loss caused region-specific MYH4+ fiber atrophy, MYH1/MYH2 fiber type shifts resembling ALS G93A mouse phenotypes, and progressive neuromuscular junction fragmentation with increased motoneuron terminal sprouting and ectopic reinnervation. These findings establish c-MAF as a critical mediator linking motoneuron activity to muscle gene regulation, fiber integrity, and neuromuscular junction maintenance in fast glycolytic fibers.

physiology↗

bioRxiv2025

Social Perspectives on Larvicide-Based Mosquito Control in Urban Quebec

The spreading of Bacillus thuringiensis israelensis (Bti) in urban waterways, as a biological larvicide to control biting insect populations and mitigate disease transmission, has been subject to scientific scrutiny due to its potential environmental impacts. Public and political discussions have revealed recurring opinions that reflect broader social perspectives. While scientific research on Bti progresses, knowledge of public understanding and perspectives, which are important for decision-making, remains limited. The main objective of this research was to identify and compare the social perspectives of Quebec citizens, primarily in the city of Gatineau, regarding the use of Bti for mosquito and black fly control in aquatic environments. We used Q methodology, a mixed approach combining both quantitative and qualitative methods to identify social perspectives related to the use of Bti. Our analysis revealed three social perspectives, which account for 51% of the explained variance. They reflect the broader range of opinion within citizens, and are described as "The critical environmentalist", "The diligent mosquito hunter", and "The Bti enthusiast". Each accounting for 29%, 12% and 10% of the explained variance, respectively. The common thread across all three perspectives is the minimal public awareness and understanding of Bti and its environmental implications. Providing a first characterization of social perspectives in North America regarding larvicides, this research contributes to a more comprehensive understanding of public opinion and informs the development of inclusive and transparent policies.

scientific communication and education↗

bioRxiv2025

Spatiotemporal Gray Matter Plasticity During Chronification of Preclinical Neuropathic Pain

Chronic neuropathic pain is increasingly recognized as a brain disease characterized by time-dependent structural and functional reorganization of key neural circuits. While human imaging studies implicate widespread changes in network connectivity and gray matter density (GMD), animal models enable direct longitudinal mapping of such plasticity. Here, we applied high-resolution structural MRI in a rat model of chronic pain (spared nerve injury, SNI) and quantified GMD changes across 134 brain regions. Dynamic weight bearing analysis confirmed persistent pain in SNI rats, validating the chronic pain phenotype in our experimental cohort. Longitudinal MRI revealed significant GMD alterations in 31 regions, predominantly within limbic, prefrontal, and cingulate circuits, representing 21% of total brain volume. Among this affected volume, over 17% of brain volume demonstrated GMD increases while only ~3% showed GMD decreases, indicating a heterogeneous neuroplastic response. Specifically, the Frontal Association Cortex exhibited an approximate 10% increase in GMD, the Primary Cingular Cortex showed a modest increase of about 2%, and the Amygdalohyppocampic Area demonstrated a ~10% decrease in GMD over 28 days. Primary sensory, parietal, visual, retrosplenial, and temporal cortices remained largely unaffected. No significant changes were observed in healthy animals over the same period, highlighting the specificity of brain reorganization to persistent neuropathic pain. These findings reaffirm the ability of MRI to robustly quantify pain-induced neuroanatomical remodeling but leave open critical questions about the underlying cellular and molecular mechanisms. Future studies integrating histological and molecular approaches are needed to determine the precise substrate and reversibility of these structural changes, with the goal of identifying therapeutic targets to prevent or reverse maladaptive neuroplasticity in chronic.

neuroscience↗