Proteasome blockers inhibit TNF-alpha release by lipopolysaccharide stimulated macrophages and microglia: implications for HIV-1 dementia.
HIV-1 infection of the central nervous system can cause severe neurologic disease although only microglial cells and brain macrophages are susceptible to productive viral infection. Substances secreted by infected cells are thought to cause disease indirectly. Tumor necrosis factor alpha (TNF-alpha) is one candidate neurotoxin and is upregulated during HIV-1 infection of the brain, likely via activation of the transcription factor NF-kappaB. We used the proteasome inhibitors, MG132 and ALLN (N-acetyl-Leu-Leu-Norleucinal), to inhibit NF-kappaB activation in primary human fetal microglia (PHFM) and primary monocyte derived-macrophages, and showed that they could block TNF-alpha release stimulated by lipopolysaccharide (LPS) or TNF-alpha. In addition, we performed electrophoretic mobility shift analysis and determined that in microglia, the p50/p65 heterodimer of NF-kappaB is activated by LPS stimulation, and is inhibited by MG132. Thus, blockade of NF-kappaB activation in microglia in vitro can decrease production of TNF-alpha and may prove to be a novel strategy for treating HIV-1 dementia.
Fine
S M
SM
Department of Medicine, University of Rochester Medical Center, NY 14642, USA. steven_fine@urmc.rochester.edu
Maggirwar
S B
SB
Elliott
P R
PR
Epstein
L G
LG
Gelbard
H A
HA
Dewhurst
S
S
D015526:AIDS Dementia Complex / Q000276:immunology* / Q000378:metabolism; D002478:Cells, Cultured; D003546:Cysteine Endopeptidases / Q000378:metabolism*; D015853:Cysteine Proteinase Inhibitors / Q000494:pharmacology; D015342:DNA Probes; D004789:Enzyme Activation / Q000187:drug effects; D005333:Fetus / Q000166:cytology; D015870:Gene Expression / Q000276:immunology; D015497:HIV-1; D006801:Humans; D007976:Leupeptins / Q000494:pharmacology; D008070:Lipopolysaccharides / Q000494:pharmacology; D008264:Macrophages / Q000201:enzymology / Q000276:immunology* / Q000821:virology; D017628:Microglia / Q000201:enzymology / Q000276:immunology* / Q000821:virology; D009097:Multienzyme Complexes / Q000378:metabolism*; D016328:NF-kappa B / Q000235:genetics / Q000276:immunology; D010587:Phagocytosis / Q000276:immunology; D046988:Proteasome Endopeptidase Complex; D014409:Tumor Necrosis Factor-alpha / Q000235:genetics / Q000276:immunology / Q000378:metabolism*
D015853:Cysteine Proteinase Inhibitors; D015342:DNA Probes; D007976:Leupeptins; D008070:Lipopolysaccharides; D009097:Multienzyme Complexes; D016328:NF-kappa B; D014409:Tumor Necrosis Factor-alpha; C063261:acetylleucyl-leucyl-norleucinal; D003546:Cysteine Endopeptidases; D046988:Proteasome Endopeptidase Complex; C072553:benzyloxycarbonylleucyl-leucyl-leucine aldehyde