Effect of Lipopolysaccharide on the Morphology and Integrin Immunoreactivity of Ramified Microglia in the Mouse Brain and in Cell Culture

doi:10.1006/exnr.2000.7575

Experimental Neurology

Volume 168, Issue 1, March 2001, Pages 32-46

https://doi.org/10.1006/exnr.2000.7575 Get rights and content

Abstract

Microglial cells form the first line of defense in brain infection. They are related to monocytes and macrophages and can be readily activated by cell wall components of bacteria such as lipopolysaccharides (LPS). In the present study, we explored the effect of this endotoxin in mouse on the morphology of microglia and their immunoreactivity for the integrin family of cell adhesion molecules in vitro and in vivo. Subcutaneous injection of LPS led to a dose-dependent activation of αMβ2-positive microglia, with a saturating effect at 1 μg LPS in the blood–brain barrier deficient area postrema, at 10 μg in the directly adjacent tissue, and at 100 μg throughout the brainstem and cerebellum. Morphologically, this activation was characterized by the swelling of the microglial cell body, a thickening of the proximal processes, and a reduction in distal ramification. Microglial immunoreactivity for the integrins α4β1, α5β1, α6β1, and αMβ2 was strongly increased. In vitro, ramified microglia were obtained using a coculture on top of a confluent astrocyte monolayer. Two days exposure to LPS resulted in a morphological activation of the cultured cells with an increase of the integrin immunoreactivity for α5 (5.7-fold), α4 (3.1-fold), β1 (2.3-fold), and αM (1.5-fold), and a decrease in the α6-staining intensity by 39%. Even a sublethal dose of LPS (3 mg in vivo and 500 μg/ml in vitro, respectively) did not induce the phagocyte-associated integrin αXβ2 (CD11c/CD18, p150,95) and did not lead to a morphological transformation of the ramified microglia into phagocytes.

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Regular ArticleEffect of Lipopolysaccharide on the Morphology and Integrin Immunoreactivity of Ramified Microglia in the Mouse Brain and in Cell Culture

Abstract

Brain Res.

Neuroscience

Exp. Neurol.

Neuroscience

Neurochem. Int.

Neuroscience

Brain Res.

J. Neuroimmunol.

Mol. Brain Res.

Brain Res.

Trends Neurosci.

Neurochem. Int.

J. Neuroimmunol.

Brain Res.

Neurosci. Res.

Biochem. Biophys. Res. Commun.

J. Neuroimmunol.

Trends Neurosci.

Neuroscience

Brain Res. Rev.

Neuroscience

Biochem. Biophys. Res. Commun.

Exp. Neurol.

Brain Res.

Exp. Neurol.

Neuroscience

Effect of bacterial wall polysaccharide (LPS) on morphology, motility, and cytoskeletal organization of microglia in cultures

J. Neurosci. Res.

Cytotoxicity of microglia

Glia

Soluble tumor necrosis factor receptor inhibits interleukin 12 production by stimulated human adult microglial cells in vitro

J. Clin. Invest.

Regulation of CD14 expression on human adult central nervous system-derived microglia

J. Neurosci. Res.

Cytokine-mediated regulation of MHC1, MHC2 and B7-2 in the axotomized mouse facial motor nucleus

Soc. Neurosci. Abstracts

Effects of αMβ2-integrin stimulation and deletion on the cellular reaction in mouse central nervous system

Clin. Neuropathol.

Targeted expression of major histocompatibility complex (MHC) class II molecules demonstrates that dendritic cells can induce negative but not positive selection of thymocytes in vivo

J. Exp. Med.

Lipopolysaccharide induces expression of tumour necrosis factor alpha in rat brain: Inhibition by methylprednisolone and by rolipram

Br. J. Pharmacol.

Differential tumor necrosis factor alpha expression by astrocytes from experimental allergic encephalomyelitis-susceptible and -resistant rat strains

J. Exp. Med.

Crucial role of TNF receptor type 1 (p55), but not of TNF receptor type 2 (p75), in murine toxoplasmosis

J. Immunol.

A new function for the LDL receptor: Transcytosis of LDL across the blood-brain barrier

J. Cell Biol.

Receptor-mediated transcytosis of transferrin through blood–brain barrier endothelial cells

Am. J. Physiol.

Microglia and cytokines in neurological disease, with special reference to AIDS and Alzheimer's disease

Glia

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J. Neurosci.

Morphological, immunophenotypical and electrophysiological properties or resting microglia in vitro

Eur. J. Neurosci.

A quantitative analysis of the microglial cell reaction in central primary sensory projection territories following peripheral nerve injury in the adult rat

Exp. Brain Res.

Regular Article
Effect of Lipopolysaccharide on the Morphology and Integrin Immunoreactivity of Ramified Microglia in the Mouse Brain and in Cell Culture