Microglial cells maintain the immunological integrity of the healthy brain and can exert protection from traumatic injury. During ischemic tissue damage such as stroke, peripheral immune cells acutely infiltrate the brain and may exacerbate neurodegeneration. Whether and how microglia can protect from this insult is unknown. Polymorphonuclear neutrophils (PMNs) are a prominent immunologic infiltrate of ischemic lesions in vivo. Here, we show in organotypic brain slices that externally applied invading PMNs massively enhance ischemic neurotoxicity. This, however, is counteracted by additional application of microglia. Time-lapse imaging shows that microglia exert protection by rapid engulfment of apoptotic, but, strikingly, also viable, motile PMNs in cell culture and within brain slices. PMN engulfment is mediated by integrin- and lectin-based recognition. Interference with this process using RGDS peptides and N-acetyl-glucosamine blocks engulfment of PMNs and completely abrogates the neuroprotective function of microglia. Thus, engulfment of invading PMNs by microglia may represent an entirely new mechanism of CNS immune privilege.
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http://dx.doi.org/10.1523/JNEUROSCI.0060-08.2008 | DOI Listing |
mBio
January 2025
Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, California, USA.
is an obligate intracellular, tick-borne bacterial pathogen that can cause eschar-associated rickettsiosis in humans. invades host cells, escapes from vacuoles into the cytosol, and undergoes two independent modes of actin-based motility mediated by effectors RickA or Sca2. Actin-based motility of enables bacteria to enter protrusions of the host cell plasma membrane that are engulfed by neighboring host cells.
View Article and Find Full Text PDFElife
December 2024
Trinity Translational Medicine Institute, St James's Hospital, Trinity College Dublin, The University of Dublin, Dublin, Ireland.
Diabetic neuropathy is frequently accompanied by pain and loss of sensation attributed to axonal dieback. We recovered dorsal root ganglia (DRGs) from 90 organ donors, 19 of whom had medical indices for diabetic painful neuropathy (DPN). Nageotte nodules, dead sensory neurons engulfed by non-neuronal cells, were abundant in DPN DRGs and accounted for 25% of all neurons.
View Article and Find Full Text PDFJ Integr Neurosci
September 2024
Department of Neurosurgery, Jiangnan University Medical Center, 214005 Wuxi, Jiangsu, China.
Phagocytosis is the process by which certain cells or organelles internalise foreign substances by engulfing them and then digesting or disposing of them. Microglia are the main resident phagocytic cells in the brain. It is generally believed that microglia/macrophages play a role in guiding the brain's repair and functional recovery processes.
View Article and Find Full Text PDFbioRxiv
September 2024
Department of Neuroscience, University of Virginia, Charlottesville, VA 22903.
As glia mature, they undergo glial tiling to abut one another without invading each other's boundaries. Upon the loss of the secreted neurotrophin Spätzle3 (Spz3), cortex glia transform morphologically and lose their intricate interactions with neurons and surrounding glial subtypes. Here, we reveal that all neighboring glial cell types (astrocytes, ensheathing glia, and subperineurial glia) react by extending processes into the previous cortex glial territory to compensate for lost cortex glial function and reduce the buildup of neuronal debris.
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