The stimulation of inducible nitric-oxide synthase by the prion protein fragment 106--126 in human microglia is tumor necrosis factor-alpha-dependent and involves p38 mitogen-activated protein kinase.
A synthetic peptide consisting of amino acid residues 106-126 of the human prion protein (PrP-(106--126)) has been previously demonstrated to be neurotoxic and to induce microglial activation. The present study investigated the expression of the inducible form of the nitric-oxide synthase (NOS-II) in human microglial cells treated with PrP-(106--126). Using reverse transcriptase-polymerase chain reaction, we found that PrP-(106--126) induces NOS-II gene expression after 24 h of treatment and that this effect is accompanied by a peak of nuclear factor kappa B (NF-kappa B) binding at 30 min as evaluated by electrophoretic mobility shift assay. Since our previous data demonstrated tumor necrosis factor-alpha (TNF-alpha) to be a potent inducer of NOS-II in these cells, we analyzed the expression of this cytokine in PrP-(106--126)-treated microglia. PrP-(106--126) caused the release of TNF-alpha as detected by enzyme-linked immunosorbent assay, and a blocking antibody, anti-TNF-alpha, abolished NOS-II induction elicited by this peptide. Moreover, PrP-(106-126) activates p38 mitogen-activated protein kinase, and the inhibition of this pathway determines the ablation of NF-kappa B binding induced by this fragment peptide.
Fabrizi
C
C
Dipartimento di Biologia, Università di Roma Tre, Viale Marconi 446, 00146, Roma, Italy.
Silei
V
V
Menegazzi
M
M
Salmona
M
M
Bugiani
O
O
Tagliavini
F
F
Suzuki
H
H
Lauro
G M
GM
D002478:Cells, Cultured; D005786:Gene Expression Regulation / Q000187:drug effects; D006801:Humans; D017628:Microglia / Q000378:metabolism*; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism*; D019001:Nitric Oxide Synthase / Q000096:biosynthesis* / Q000235:genetics; D052247:Nitric Oxide Synthase Type II; D010446:Peptide Fragments / Q000494:pharmacology*; D011328:Prions / Q000494:pharmacology*; D015398:Signal Transduction / Q000187:drug effects / Q000235:genetics; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism*; D048051:p38 Mitogen-Activated Protein Kinases
D010446:Peptide Fragments; D011328:Prions; D014409:Tumor Necrosis Factor-alpha; C082632:prion protein (106-126); C496319:NOS2 protein, human; D019001:Nitric Oxide Synthase; D052247:Nitric Oxide Synthase Type II; D020928:Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases