Effect of ammonia on endocytosis and cytokine production by immortalized human microglia and astroglia cells.
Ammonium acetate decreased in a concentration-dependent manner the phagocytic uptake of mannosylated latex microspheres and of yeast by immortalized human microglia (CHME-5) and astroglioma (GL-15) cells. In both cell lines ammonium acetate affected also the secretion of certain cytokines. The most conspicuous effects were the following: in both cell lines ammonium acetate enhanced greatly the secretion of tumor necrosis factor-alpha in the absence of any other stimulus. in the human microglia cells ammonia decreased the constitutive secretion of interleukin-6, but it enhanced the stimulated (interleukin-1 alpha, tumor necrosis factor-alpha, gamma-interferon and gamma-interferon + tumor necrosis factor-alpha) secretion of interleukin-8. In the astroglioma cell line, the stimulated release of tumor necrosis factor-alpha, interleukin-6 and interleukin-8 was diminished by ammonium acetate. The magnitude of the ammonia-effect depended on the stimulating agent (lipopolysaccharide, interleukin-1 alpha, tumor necrosis factor-alpha, gamma-interferon). The results are discussed with regard to their potential importance in the pathogenesis of human diseases with elevated blood and brain ammonia concentrations.
Atanassov
C L
CL
UPR 9021-Immunochimie des Peptides et des Virus, Institut de Biologie Moléculaire et Cellulaire du CNRS, Strasbourg, France.
Muller
C D
CD
Dumont
S
S
Rebel
G
G
Poindron
P
P
Seiler
N
N
D000085:Acetates / Q000494:pharmacology; D000641:Ammonia / Q000494:pharmacology*; D001253:Astrocytes / Q000378:metabolism*; D002460:Cell Line; D016207:Cytokines / Q000096:biosynthesis*; D004705:Endocytosis / Q000187:drug effects*; D006801:Humans; D016209:Interleukin-8 / Q000037:antagonists & inhibitors; D017628:Microglia / Q000378:metabolism*; D010587:Phagocytosis / Q000187:drug effects; D013268:Stimulation, Chemical; D014409:Tumor Necrosis Factor-alpha / Q000037:antagonists & inhibitors; D000093242:Interleukin-6 Inhibitors
D000085:Acetates; D000641:Ammonia; D016207:Cytokines; D016209:Interleukin-8; D014409:Tumor Necrosis Factor-alpha; D000093242:Interleukin-6 Inhibitors; C018824:ammonium acetate