title: Lipopolysaccharide-induced increase in signalling in hippocampus is abrogated by IL-10--a role for IL-1 beta?
abstract: Parenterally administered lipopolysaccharide (LPS) increases the concentration of the pro-inflammatory cytokine interleukin-1beta (IL-1beta) in the rat hippocampus and evidence suggests that this effect plays a significant role in inhibiting long-term potentiation (LTP). The anti-inflammatory cytokine IL-10, antagonizes certain effects of IL-1beta, so if the effects of LPS are mediated through an increase in IL-1beta, it might be predicted that IL-10 would also abrogate the effect of LPS. Here, we report that IL-10 reversed the inhibitory effect of LPS on LTP and the data couple this with an inhibitory effect on the LPS-induced increase in IL-1beta. LPS treatment increased hippocampal expression of IL-1 receptor Type I protein. Consistent with the LPS-induced increases in IL-1beta concentration and receptor expression, were downstream changes which included enhanced phosphorylation of IRAK and the stress-activated kinases, JNK and p38; these LPS-induced changes were reversed by IL-10, which concurs with the idea that these events are triggered by increased activation of IL-1RI by IL-1beta. We provide evidence which indicates that LPS treatment leads to evidence of cell death and this was reversed in hippocampus prepared from LPS-treated rats which received IL-10. The evidence is therefore consistent with the idea that IL-10 acts to protect neuronal tissue from the detrimental effects induced by LPS.
authors.affiliation: Institute of Neuroscience, Department of Physiology, Trinity College, Dublin, Ireland. amlynch@tcd.ie
authors.forename: Aileen M
authors.initials: AM
authors.lastname: Lynch
authors.forename: Christine
authors.initials: C
authors.lastname: Walsh
authors.forename: Ada
authors.initials: A
authors.lastname: Delaney
authors.forename: Yvonne
authors.initials: Y
authors.lastname: Nolan
authors.forename: Veronica A
authors.initials: VA
authors.lastname: Campbell
authors.forename: Marina A
authors.initials: MA
authors.lastname: Lynch
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000276:immunology; D006624:Hippocampus / Q000166:cytology / Q000201:enzymology / Q000276:immunology / Q000378:metabolism; D053590:Interleukin 1 Receptor Antagonist Protein; D007375:Interleukin-1 / Q000037:antagonists & inhibitors / Q000378:metabolism / Q000502:physiology*; D053592:Interleukin-1 Receptor-Associated Kinases; D016753:Interleukin-10 / Q000502:physiology*; D048031:JNK Mitogen-Activated Protein Kinases; D008070:Lipopolysaccharides / Q000494:pharmacology*; D017774:Long-Term Potentiation / Q000276:immunology; D048670:MAP Kinase Kinase 4; D020935:MAP Kinase Signaling System / Q000276:immunology*; D008297:Male; D020929:Mitogen-Activated Protein Kinase Kinases / Q000378:metabolism; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D011494:Protein Kinases / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D017472:Receptors, Interleukin-1 / Q000037:antagonists & inhibitors / Q000096:biosynthesis; D012795:Sialoglycoproteins / Q000378:metabolism; D015854:Up-Regulation / Q000276:immunology*; D048051:p38 Mitogen-Activated Protein Kinases
chemical_list: D053590:Interleukin 1 Receptor Antagonist Protein; D007375:Interleukin-1; D008070:Lipopolysaccharides; D017472:Receptors, Interleukin-1; D012795:Sialoglycoproteins; D016753:Interleukin-10; D011494:Protein Kinases; D053592:Interleukin-1 Receptor-Associated Kinases; D048031:JNK Mitogen-Activated Protein Kinases; D020928:Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases; D048670:MAP Kinase Kinase 4; D020929:Mitogen-Activated Protein Kinase Kinases