In vitro and in vivo induction of heme oxygenase-1 in rat glial cells: possible involvement of nitric oxide production from inducible nitric oxide synthase.
To determine whether heme oxygenase-1 (HO-1) protein is induced by endogenous nitric oxide (NO) in rat glial cultures, we examined the effects of lipopolysaccharide (LPS), interferon-gamma (IFN-gamma), and NO donors such as S-nitroso-N-acetylpenicillamine (SNAP), in mixed glial cells and in vivo rat hippocampus. In cultured glial cells, treatment with LPS induced the expression of 130-kd inducible NO synthase (iNOS) after 6 h, and NO2- accumulation and enhancement of the protein level of 33-kd HO-1 after 12 h. In addition, treatment with SNAP induced HO-1 expression after 6 h. Although NOS inhibitors such as NG-nitro-L-arginine (NNA) and NG-methyl-L-arginine did not change LPS-induced iNOS expression, these inhibitors suppressed both NO2- accumulation and the enhancement of HO-1. Immunocytochemistry showed that treatment with LPS for 24 h induced iNOS immunoreactivity predominantly in ameboid microglia, while this treatment induced HO-1-immunoreactivity in both microglia and astrocytes. In in vivo rat hippocampus, microinjection of LPS plus IFN-gamma, or SNAP after 24 h also induced HO-1 immunoreactivity in reactive microglia and astrocytes. In addition, intraperitoneal administration of NNA inhibited HO-1 immunoreactivity induced by the microinjection of LPS plus IFN-gamma. These results suggest that endogenous NO production by iNOS in microglia causes autocrine and paracrine induction of HO-1 protein in microglia and astrocytes in vitro and in rat brain.
Kitamura
Y
Y
Department of Neurobiology, Kyoto Pharmaceutical University, Japan.
Furukawa
M
M
Matsuoka
Y
Y
Tooyama
I
I
Kimura
H
H
Nomura
Y
Y
Taniguchi
T
T
D000818:Animals; D015153:Blotting, Western; D002478:Cells, Cultured; D004731:Endotoxins / Q000008:administration & dosage / Q000494:pharmacology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006419:Heme Oxygenase (Decyclizing) / Q000096:biosynthesis*; D051547:Heme Oxygenase-1; D006624:Hippocampus / Q000502:physiology; D007150:Immunohistochemistry; D007371:Interferon-gamma / Q000008:administration & dosage / Q000494:pharmacology; D008070:Lipopolysaccharides / Q000008:administration & dosage / Q000494:pharmacology; D008845:Microinjections; D009457:Neuroglia / Q000187:drug effects / Q000201:enzymology*; D009569:Nitric Oxide / Q000096:biosynthesis*; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors / Q000096:biosynthesis*; D052247:Nitric Oxide Synthase Type II; D010396:Penicillamine / Q000008:administration & dosage / Q000031:analogs & derivatives / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D011994:Recombinant Proteins; D026423:S-Nitroso-N-Acetylpenicillamine; D000254:Sodium-Potassium-Exchanging ATPase / Q000037:antagonists & inhibitors
D004731:Endotoxins; D004791:Enzyme Inhibitors; D008070:Lipopolysaccharides; D011994:Recombinant Proteins; D009569:Nitric Oxide; C044101:endotoxin, Escherichia coli; D026423:S-Nitroso-N-Acetylpenicillamine; D007371:Interferon-gamma; D019001:Nitric Oxide Synthase; D052247:Nitric Oxide Synthase Type II; C496318:Nos2 protein, rat; D006419:Heme Oxygenase (Decyclizing); D051547:Heme Oxygenase-1; D000254:Sodium-Potassium-Exchanging ATPase; D010396:Penicillamine