Display Settings:

Format

Send to:

Choose Destination
See comment in PubMed Commons below
J Neurosci. 2008 May 14;28(20):5321-30. doi: 10.1523/JNEUROSCI.3995-07.2008.

Tumor necrosis factor alpha mediates lipopolysaccharide-induced microglial toxicity to developing oligodendrocytes when astrocytes are present.

Author information

  • 1Department of Neurology and the F. M. Kirby Neurobiology Center, Children's Hospital Boston, Harvard Medical School, Boston, Massachusetts 02115, USA. jrli@cvm.tamu.edu

Abstract

Reactive microglia and astrocytes are present in lesions of white matter disorders, such as periventricular leukomalacia and multiple sclerosis. However, it is not clear whether they are actively involved in the pathogenesis of these disorders. Previous studies demonstrated that microglia, but not astrocytes, are required for lipopolysaccharide (LPS)-induced selective killing of developing oligodendrocytes (preOLs) and that the toxicity is mediated by microglia-derived peroxynitrite. Here we report that, when astrocytes are present, the LPS-induced, microglia-dependent toxicity to preOLs is no longer mediated by peroxynitrite but instead by a mechanism dependent on tumor necrosis factor-alpha (TNFalpha) signaling. Blocking peroxynitrite formation with nitric oxide synthase (NOS) inhibitors or a decomposition catalyst did not prevent LPS-induced loss of preOLs in mixed glial cultures. PreOLs were highly vulnerable to peroxynitrite; however, the presence of astrocytes prevented the toxicity. Whereas LPS failed to kill preOLs in cocultures of microglia and preOLs deficient in inducible NOS (iNOS) or gp91(phox), the catalytic subunit of the superoxide-generating NADPH oxidase, LPS caused a similar degree of preOL death in mixed glial cultures of wild-type, iNOS-/-, and gp91(phox-/-) mice. TNFalpha neutralizing antibody inhibited LPS toxicity, and addition of TNFalpha induced selective preOL injury in mixed glial cultures. Furthermore, disrupting the genes encoding TNFalpha or its receptors TNFR1/2 completely abolished the deleterious effect of LPS. Our results reveal that TNFalpha signaling, rather than peroxynitrite, is essential in LPS-triggered preOL death in an environment containing all major glial cell types and underscore the importance of intercellular communication in determining the mechanism underlying inflammatory preOL death.

PMID:
18480288
[PubMed - indexed for MEDLINE]
PMCID:
PMC2677805
Free PMC Article

Images from this publication.See all images (8)Free text

Fig. 1
Fig. 2
Fig. 3
Fig. 4
Fig. 5
Fig. 6
Fig. 7
Fig. 8

Publication Types, MeSH Terms, Substances, Grant Support

PubMed Commons home

PubMed Commons

0 comments
How to join PubMed Commons

    Supplemental Content

    Full text links

    Icon for HighWire Icon for PubMed Central
    Loading ...
    Write to the Help Desk