Comparison of tumor necrosis factor-alpha effect on the expression of iNOS in macrophage and cardiac myocytes.
Proinflammatory cytokines, including tumor necrosis factor-alpha (TNF-alpha), are elevated during cardiopulmonary bypass (CPB), heart failure, and inflammatory cardiac and systemic diseases. Elevated TNF-alpha has been linked to diminished cardiac function, decreased systemic vascular resistance, as well as renal and pulmonary dysfunction. It is understood that myocardial tissues can express TNF-alpha, which results in the induction of inducible nitric oxide synthase (iNOS) leading to a significant decline in cardiac function and other direct effects. The hypothesis of this study was to determine if TNF-alpha would stimulate iNOS and its product nitric oxide (NO) similarly in immortalized macrophage and cardiac myocytes. Cultured macrophages (RAW 264.7) and cardiac myocytes (HL-1) were placed into two treatment groups and a control. The treatments included: (1) TNF-alpha and lipopolysaccharide (LPS); and (2) LPS, TNF-alpha, interleukin-1beta (IL-1beta) and interferon-gamma (IFN-gamma) incubated for 8 h. The macrophage expression of iNOS increased by 365% (p < 0.01) and its product, NO, increased proportionally. The expression of iNOS in the cardiac myocyte did not increase with TNF-alpha and LPS. However, with the addition of IFN-alpha and IL-1beta iNOS increased to 140% of control (p < 0.05). Myocyte cGMP and NO did not increase significantly with TNF-alpha treatment. This study suggests that HL-1 myocyte iNOS cannot be induced by TNF-alpha, unlike macrophage iNOS. Furthermore, the resultant cardiac dysfunction, secondary to proinflammatory cytokines effects, is regulated via diverse pathways.
Sanders
D B
DB
Circulatory Sciences Graduate Perfusion Program, Sarver Heart Center, University of Arizona, Tucson 85724, USA.
Larson
D F
DF
Hunter
K
K
Gorman
M
M
Yang
B
B
D000818:Animals; D002315:Cardiopulmonary Bypass / Q000009:adverse effects; D002478:Cells, Cultured / Q000187:drug effects; D006152:Cyclic GMP / Q000096:biosynthesis; D004347:Drug Interactions; D004790:Enzyme Induction / Q000187:drug effects; D007371:Interferon-gamma / Q000494:pharmacology; D007375:Interleukin-1 / Q000494:pharmacology; D008070:Lipopolysaccharides / Q000494:pharmacology; D008264:Macrophages / Q000201:enzymology*; D051379:Mice; D015428:Myocardial Reperfusion Injury / Q000378:metabolism; D009206:Myocardium / Q000201:enzymology*; D009569:Nitric Oxide / Q000096:biosynthesis; D019001:Nitric Oxide Synthase / Q000096:biosynthesis*; D052247:Nitric Oxide Synthase Type II; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology*
D007375:Interleukin-1; D008070:Lipopolysaccharides; D014409:Tumor Necrosis Factor-alpha; D009569:Nitric Oxide; D007371:Interferon-gamma; D019001:Nitric Oxide Synthase; D052247:Nitric Oxide Synthase Type II; C496317:Nos2 protein, mouse; D006152:Cyclic GMP