A characteristic subset of microglia expressing CD11c appears in response to brain damage. However, the functional role of CD11c microglia, as well as the mechanism of its induction, are poorly understood. Here we report that the genetic ablation of signal regulatory protein α (SIRPα), a membrane protein, induced the emergence of CD11c microglia in the brain white matter. Mice lacking CD47, a physiological ligand of SIRPα, and microglia-specific SIRPα-knockout mice exhibited the same phenotype, suggesting that an interaction between microglial SIRPα and CD47 on neighbouring cells suppressed the emergence of CD11c microglia. A lack of SIRPα did not cause detectable damage to the white matter, but resulted in the increased expression of genes whose expression is characteristic of the repair phase after demyelination. In addition, cuprizone-induced demyelination was alleviated by the microglia-specific ablation of SIRPα. Thus, microglial SIRPα suppresses the induction of CD11c microglia that have the potential to accelerate the repair of damaged white matter.
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http://dx.doi.org/10.7554/eLife.42025 | DOI Listing |
J Neurochem
January 2025
Center for Translational Research in Neurodegenerative Disease, College of Medicine, University of Florida, Gainesville, Florida, USA.
Neuroinflammation plays an important role in the pathological cascade of Alzheimer's disease (AD) along with aggregation of extracellular amyloid-β (Aβ) plaques and intracellular aggregates of tau protein. In animal models of amyloidosis, local immune activation is centered around Aβ plaques, which are usually of uniform morphology, dependent on the transgenic model used. In postmortem human brains a diversity of Aβ plaque morphologies is seen including diffuse plaques (non-neuritic plaques, non-NP), dense-core plaques, cotton-wool plaques, and NP.
View Article and Find Full Text PDFBrain Pathol
December 2024
Neurology Section of Department of Neuroscience, Biomedicine and Movement, University of Verona, Verona, Italy.
Among the intrathecal inflammatory niches where compartmentalized inflammation persists and plays a pivotal role in progressive multiple sclerosis (MS), choroid plexus (CP) has recently received renewed attention. To better characterize the neuropathological/molecular correlates of CP in progressive MS and its potential link with other brain inflammatory compartments, such as perivascular spaces and leptomeninges, the levels, composition and phenotype of CP immune infiltration in lateral ventricles of the hippocampus were examined in 40 post-mortem pathologically confirmed MS and 10 healthy donors, using immunochemistry/immunofluorescence and in-situ sequencing. Significant inflammation was detected in the CP of 21 out of the 40 MS cases (52%).
View Article and Find Full Text PDFInt J Mol Sci
July 2024
Instituto de Biomedicina de Sevilla, IBiS/Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, 41013 Sevilla, Spain.
Aquaporin-4 (AQP4) expression is associated with the development of congenital hydrocephalus due to its structural role in the ependymal membrane. Gene expression analysis of periaqueductal tissue in AQP4-knockout (KO) mice at 11 days of age (P11) showed a modification in ependymal cell adhesion and ciliary protein expression that could alter cerebrospinal fluid homeostasis. A microglial subpopulation of CD11c+ cells was overexpressed in the periaqueductal tissue of mice that did not develop hydrocephalus, suggesting a possible protective effect.
View Article and Find Full Text PDFMedicine (Baltimore)
August 2024
College of Sport and Health, Shandong Sport University, Jinan, China.
Renal clear cell carcinoma (RCC) is a type of malignant tumor, which, in addition to surgical resection, radiotherapy, and chemotherapy, has been widely treated through immunotherapy recently. However, the influence of the tumor microenvironment and the infiltrating immune cells within it on immunotherapy remains unclear. It is imperative to study the interactions between various immune cells of RCC.
View Article and Find Full Text PDFActa Neuropathol
July 2024
Institute of Neuropathology, Faculty of Medicine, University of Freiburg, Breisacher Str. 64, 79106, Freiburg, Germany.
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