Biology subjects

Vallieres, L.

Publications and source records attributed to Vallieres, L..

4 recordsLinked to original sources

bioRxiv2026

Natural Microbial Enrichment Modulates Microglial States and Transcriptional Programs Relevant to Alzheimer's Disease

The diversity of environmental microbial exposure is a key driver of immune maturation and host defense; however, its impact on brain immunity and neurodegenerative diseases remains poorly documented. Here, we show that controlled indoor rewilding, by introducing a natural farm-like environment into laboratory housing, reshapes peripheral and central nervous system (CNS) immune networks in wild-type (WT) and 5xFAD mice, a model of Alzheimers disease (AD). Compared with traditional specific pathogen-free (SPF) housing, rewilded mice exhibited systemic shifts toward mature immune phenotypes, including increases in effector and memory B and T cells, expansion of plasma cell populations, and alterations in immunoglobulin isotypes. In the brain, indoor rewilding recalibrated microglial activation of SPF-5xFAD mice, attenuating pro-inflammatory transcriptional programs while enhancing homeostatic, complement, and phagocytic signatures. A strong transcriptional convergence was observed between rewilded and wild mice, with rewilded 5xFAD mice exhibiting greater similarity to human AD transcriptional profiles. Morphological and histochemical analyses confirmed that rewilded microglia adopt metabolically adaptable, homeostatic states that influence amyloid-{beta} plaque binding and clearance. Collectively, these findings suggest that microbial diversity through "dirty" mouse modeling could enhance the translational relevance of neuroimmunology and neurodegenerative disease research.

immunology↗

bioRxiv2025

Indoor Rewilding of Laboratory Mice Recalibrates Pulmonary Mucosal Immunity and Mechanics

Laboratory mice raised under specific-pathogen-free (SPF) conditions experience restricted microbial and antigenic exposure, which favours an immature immune system and limits their translational value for respiratory research. While microbial enrichment in "dirty" mouse models restores immune maturation, its impact on integrated respiratory function and model transferability to human disease remains understudied. Here, we tested whether ecological exposure through indoor rewilding of SPF-reared mice could reshape immune complexity and recalibrate pulmonary physiology. Two-month-old female C57BL/6J mice were housed for three months under SPF or indoor-rewilding conditions and assessed for immune, mechanical, and systemic parameters. Rewilded mice exhibited expanded pulmonary immune subsets, increased dendritic-cell immune checkpoint, with TNF/IFN-{gamma} activation coupled to regulatory IL-10 signaling. Despite sustained exposure, the alveolar-capillary barrier integrity was preserved. Functionally, respiratory oscillometry revealed improved pulmonary mechanics, including lower airway resistance, higher compliance, and reduced airway responsiveness to methacholine. Systemic cytokine analyses indicated compartmentalized pulmonary immune activation, maintaining an overall anti-inflammatory balance. Importantly, PRIA screening detected no reportable pathogens introduced during rewilding, while cecal shotgun metagenomics confirmed microbial enrichment. Together, these findings demonstrate that indoor rewilding reestablishes coordinated lung immune and mechanical homeostasis in SPF-reared mice, providing a safe and scalable model for studying human-like mucosal immunity and respiratory physiology with broad implications for preclinical respiratory research and therapeutic testing.

immunology↗

bioRxiv2024

Turncoat antibodies unmasked in a model of autoimmune demyelination: from biology to therapy

Autoantibodies contribute to many autoimmune diseases, yet there is no approved therapy to neutralize them selectively. A popular mouse model, experimental autoimmune encephalomyelitis (EAE), could serve to develop such a therapy, provided we can better understand the nature and importance of the autoantibodies involved. Here we report the discovery of autoantibody-secreting extrafollicular plasmablasts in EAE induced with specific myelin oligodendrocyte glycoprotein (MOG) antigens. Single-cell RNA sequencing reveals that these cells produce non-affinity-matured IgG antibodies. These include pathogenic antibodies competing for shared binding space on MOGs extracellular domain. Interestingly, the synthetic anti-MOG antibody 8-18C5 can prevent the binding of pathogenic antibodies from either EAE mice or people with MOG antibody disease (MOGAD). Moreover, an 8-18C5 variant carrying the NNAS mutation, which inactivates its effector functions, can reduce EAE severity and promote functional recovery. In brief, this study provides not only a comprehensive characterization of the humoral response in EAE models, but also a proof of concept for a novel therapy to antagonize pathogenic anti-MOG antibodies.

immunology↗

bioRxiv2018

MicroRNA-223 protects neurons from degeneration in Experimental Autoimmune Encephalomyelitis

Multiple sclerosis (MS) is an autoimmune disease characterized by demyelination and neurodegeneration in the brain, spinal cord and optic nerve. Neuronal degeneration and death underlie progressive forms of MS and cognitive dysfunction. Neuronal damage is triggered by numerous harmful factors in the brain that engage diverse signalling cascades in neurons thus therapeutic approaches to protect neurons will need to focus on agents that can target broad biological processes. To target the broad spectrum of signaling events that mediate neurodegeneration in MS we have focused on non-coding small microRNAs (miRNAs). microRNAs are epigenetic regulators of protein expression, targeting messenger RNAs (mRNAs) and inhibiting their translation. Dysregulation of miRNAs has been described in many neurodegenerative diseases including MS. In this study we identified two miRNAs, miR-223-3p and miR-27a-3p, that were upregulated in neurons in the experimental autoimmune encephalomyelitis (EAE) mouse model of CNS inflammation and in active MS lesions. Overexpression of miR-27a-3p or miR-223-3p protected dissociated cortical neurons from degeneration in response to peripheral blood mononuclear cell conditioned media (PBMC-CM). Introduction of miR-223-3p in vivo in mouse retinal ganglion cells (RGCs) protected RGC axons from degeneration in the EAE model. By in silico analysis we found that mRNAs in the glutamate receptor (GluR) pathway are enriched in miR-27a-3p and miR-223-3p targets. Antagonism of the GluR pathway protected neurons from PBMC-CM-dependent degeneration. Our results suggest that miR-223-3p and miR-27a-3p are upregulated in response to inflammation to mediate a compensatory neuroprotective gene expression program that desensitizes neurons to glutamate by downregulating mRNAs involved in GluR signalling.

neuroscience↗