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Microglia depletion exacerbates demyelination and impairs remyelination in a neurotropic coronavirus infection
Journal article   Open access   Peer reviewed

Microglia depletion exacerbates demyelination and impairs remyelination in a neurotropic coronavirus infection

Alan Sariol, Samantha Mackin, Merri-Grace Allred, Chen Ma, Yu Zhou, Qinran Zhang, Xiufen Zou, Juan E Abrahante, David K Meyerholz and Stanley Perlman
Proceedings of the National Academy of Sciences - PNAS, Vol.117(39), pp.24464-24474
09/29/2020
DOI: 10.1073/pnas.2007814117
PMCID: PMC7533697
PMID: 32929007
url
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7533697View
Published (Version of record) Open Access

Abstract

Microglia are considered both pathogenic and protective during recovery from demyelination, but their precise role remains ill defined. Here, using an inhibitor of colony stimulating factor 1 receptor (CSF1R), PLX5622, and mice infected with a neurotropic coronavirus (mouse hepatitis virus [MHV], strain JHMV), we show that depletion of microglia during the time of JHMV clearance resulted in impaired myelin repair and prolonged clinical disease without affecting the kinetics of virus clearance. Microglia were required only during the early stages of remyelination. Notably, large deposits of extracellular vesiculated myelin and cellular debris were detected in the spinal cords of PLX5622-treated and not control mice, which correlated with decreased numbers of oligodendrocytes in demyelinating lesions in drug-treated mice. Furthermore, gene expression analyses demonstrated differential expression of genes involved in myelin debris clearance, lipid and cholesterol recycling, and promotion of oligodendrocyte function. The results also demonstrate that microglial functions affected by depletion could not be compensated by infiltrating macrophages. Together, these results demonstrate that microglia play key roles in debris clearance and in the initiation of remyelination following infection with a neurotropic coronavirus but are not necessary during later stages of remyelination.
Inflammation Microglia - metabolism Demyelinating Diseases - virology Male Murine hepatitis virus - drug effects Murine hepatitis virus - physiology Myelin Sheath - metabolism Immunity, Cellular - drug effects Spinal Cord - pathology Demyelinating Diseases - immunology Microglia - pathology Female Demyelinating Diseases - pathology Organic Chemicals - administration & dosage Disease Models, Animal Receptors, Granulocyte-Macrophage Colony-Stimulating Factor - antagonists & inhibitors Microglia - drug effects Myelin Sheath - pathology Mice, Inbred C57BL Gene Expression Regulation Organic Chemicals - adverse effects Coronavirus Infections - immunology Oligodendroglia - pathology Spinal Cord - immunology Animals Coronavirus Infections - virology Coronavirus Infections - pathology Mice Remyelination - genetics

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