Biology subjects

Bugada, V.

Publications and source records attributed to Bugada, V..

3 recordsLinked to original sources

bioRxiv2025

Mapping Leukocyte Dynamics during Neuroinflammation Identifies Meningeal Monocyte-Derived Macrophages as Drivers of Progressive Disease

Multiple sclerosis (MS) is a chronic inflammatory disease of the central nervous system (CNS) characterized by increasing disability. The cellular and molecular drivers of clinical transition towards progressive disease are poorly understood. Here, we combine single-cell profiling technologies with genetic and pharmacological perturbations across the course of murine CNS inflammation to dissect the role of the local immune landscape in disease progression. We uncover a chronic monocyte-to-phagocyte transition as a hallmark of progressive disease, characterized by the emergence of maladaptive, lipid-associated macrophages (LAMs) marked by lysosomal activation and fibrotic features. Spatial transcriptomics and multiplexed imaging revealed that these LAMs localized to the leptomeninges in close proximity to parenchymal colony-stimulating factor (CSF)-1 producing disease-associated microglia (DAMs) and meningeal granulocyte-macrophage (GM)-CSF-expressing T helper cells that license their differentiation. Interference with this local cytokine network revealed a protective role for resident microglia and implicated monocyte-derived phagocytes as key drivers of progressive neuroinflammation. Notably, LAM-like macrophages could also be identified in the meninges of people with MS, indicating a homology to human disease. By elucidating their ontogeny, spatial niche, and regulatory cytokine milieu, we provide a mechanistic framework for targeting harmful myeloid states while preserving reparative CNS immunity in progressive MS.

immunology↗

bioRxiv2024

Monocyte-derived cells but not Microglia cause Oxidative Tissue Damage in Neuroinflammation

Multiple sclerosis (MS) is characterized by neuroinflammation, oxidative stress, iron toxicity and mitochondrial dysfunction. Reactive oxygen species (ROS) produced by mononuclear phagocytes (MPs) are widely held to drive tissue damage, yet the specific roles of central nervous system (CNS)- resident versus CNS-invading MPs remain unclear. Here, by combining single-cell profiling with conditional gene targeting, we systematically dissected and interfered with ROS production across CNS MPs in a preclinical model for neuroinflammation. We show that CNS-invading monocyte derived cells (MdCs) exhibit a higher oxidative stress gene signature and produce more ROS compared to CNS-resident microglia. While NADPH oxidase 2 (NOX2), a phagocytic source of ROS, proved redundant, our findings underscore the critical role of mitochondrial ROS (mtROS) in driving oxidative tissue damage. Quenching mtROS through mitocatalase overexpression in MdCs, but not microglia, significantly alleviated neuroinflammation in mice. Thus, our study resolves a longstanding controversy, identifying MdCs as the primary driver of ROS-mediated neuropathology.

immunology↗

bioRxiv2023

Refined Tamoxifen Administration in Mice by Encouraging Voluntary Consumption of Palatable Formulations.

Drug administration in preclinical rodent models is essential for research and development of novel therapies. Compassionate administration methods have been developed, but these are mostly incompatible with water-insoluble drugs such as tamoxifen or do not allow for precise timing or dosing of the drugs. For more than two decades, tamoxifen has been administered by oral gavage or injection to CreERT2/loxP gene-modified mouse models to spatiotemporally control gene expression, with the numbers of such models steadily increasing in recent years. Animal-friendly procedures for accurately administering tamoxifen or other water-insoluble drugs would therefore have an important impact on animal welfare. Based on a previously published micropipette feeding protocol, we developed palatable formulations to encourage voluntary consumption of tamoxifen. We evaluated the acceptance of the new formulations by mice during training and treatment and assessed the efficacy of tamoxifen-mediated induction of CreERT2/loxP dependent reporter genes. Both sweetened milk and syrup-based formulations encouraged mice to consume tamoxifen voluntarily, but only sweetened milk formulations were statistically non-inferior to oral gavage in inducing CreERT2-mediated gene expression. Serum concentrations of tamoxifen metabolites, quantified using an in-house developed cell assay, confirmed the lower efficacies of syrup- as compared to sweetened milk-based formulations. We found dosing with a micropipette to be more accurate, with the added advantage that the method requires little training for the experimenter. The new palatable solutions encourage voluntary consumption of tamoxifen without loss of efficacy compared to oral gavage and thus represent a refined administration method.

animal behavior and cognition↗