Cooperative effects of interferon-gamma on the induction of NADPH oxidase by retinoic acid or 1,25(OH)2-vitamin D3 in monocytic U937 cells.
The effect of retinoic acid (RA), 1,25-dihydroxyvitamin D3 (1,25-D3) or human recombinant interferon-gamma (IFN-gamma) on the induction of NADPH oxidase was studied in premonocytic U937 cells. Differentiation with the combination of either RA (1 microM) or 1,25-D3 (10 nM) with IFN-gamma (100 IU/ml) induced NADPH oxidase activity as demonstrated by increased superoxide anion (O2-) generation in response to stimulation with phorbol myristate acetate (PMA, 100 nM). Induction of NADPH oxidase activity was preceded by increases in mRNA levels of p47-phox, p67-phox and gp91-phox, which encode three subunits of the enzyme, and immunoblot analysis of the p47-phox and p67-phox proteins revealed that the increases in mRNA levels were equally reflected by increases in protein levels. In contrast, RA, 1,25-D3 or IFN-gamma alone did not induce NADPH oxidase activity which correlated with their failure to increase p67-phox and gp91-phox mRNA levels. The mRNA of p21 rac1, a GTP-binding protein that regulates NADPH oxidase activity in macrophages, was constitutively expressed in undifferentiated cells and was not affected by differentiation. These data indicate that induction of a functional NADPH oxidase in premonocytic U937 cells requires the cooperative actions of IFN-gamma plus RA or 1,25-D3 and is reflected in the increased expression of p67-phox and gp91-phox.
Obermeier
H
H
Institut für Prophylaxe und Epidemiologie der Kreislaufkrankheiten und Medizinische Klinik, Klinikum Innenstadt, Universität München, Germany.
Sellmayer
A
A
Danesch
U
U
Aepfelbacher
M
M
D002117:Calcitriol / Q000494:pharmacology*; D002454:Cell Differentiation; D002460:Cell Line / Q000187:drug effects; D004357:Drug Synergism; D004790:Enzyme Induction; D006801:Humans; D007371:Interferon-gamma / Q000494:pharmacology*; D008562:Membrane Glycoproteins / Q000096:biosynthesis; D009000:Monocytes; D009247:NADH, NADPH Oxidoreductases / Q000096:biosynthesis*; D009252:NADPH Dehydrogenase / Q000096:biosynthesis; D000074662:NADPH Oxidase 2; D019255:NADPH Oxidases; D010750:Phosphoproteins / Q000096:biosynthesis; D012333:RNA, Messenger / Q000096:biosynthesis; D014212:Tretinoin / Q000494:pharmacology*
D008562:Membrane Glycoproteins; D010750:Phosphoproteins; D012333:RNA, Messenger; C079789:neutrophil cytosol factor 67K; D014212:Tretinoin; D007371:Interferon-gamma; D009247:NADH, NADPH Oxidoreductases; C056558:CYBB protein, human; D000074662:NADPH Oxidase 2; D019255:NADPH Oxidases; C060505:neutrophil cytosolic factor 1; D009252:NADPH Dehydrogenase; D002117:Calcitriol