Systemic Nitric Oxide Production in Human Malaria
As described in Chapter 42, niric oxide (NO) is synthesized from the amino acid l-arginine by the actions of a family of enymes, the NO synthases (NOS), each isoform of which is encoded by a separate gene. Two NOS isoforms are calcium-dependent and constitutively expressed and produce low levels of NO: NOS1 (neuronal NOS or nNOS), which is found mostly in neurons and skeletal muscle, and NOS3 (endothelial NOS or eNOS), which is found mostly in endothelial cells. NOS1 is critical for neurotransmission and learning, and NOS3 regulates vascular tone and adhesion of circulating cells. Inducible NOS (iNOS or NOS2) is transcriptionally induced by proinflammatory cytokines (such as tumor necrosis factor-α [TNF-α] and interferon-γ [IFN-γ]) and microbial products (e.g., lipoplysaccharide [LPS]). iNOS is calciumindependent, expressed by many cell types (especially mononuclear phagocytes, hepatocytes, chondrocytes and smooth muscle cells) and is responsible for high output NO production (1-3). While initial studies showed that iNOS expression within mouse macrophages resulted in high-output NO production, until recently there was doubt as to whether human macrophages were capable of producing NO. There is now clear evidence however that human monocytes and tissue macrophages can express iNOS and produce NO both in vitro and in vivo (3), including evidence from malaria-exposed Tanzanian children (4).
KeywordsPeripheral Blood Mononuclear Cell iNOS Expression Biorad Protein Assay Peripheral Blood Mononuclear Cell Sample Freeze Cell Pellet
- 4.Anstey, N. M., Weinberg, J. B., Hassanali, M. Y., Mwaikambo, E. D., Manyenga, D., Misukonis, M. A., et al. (1996) Nitric oxide in Tanzanian children with malaria: inverse relationship between malaria severity and nitric oxide production/nitric oxide synthase type 2 expression. J. Exp. Med. 184, 557–567.CrossRefPubMedGoogle Scholar
- 5.Bollag, D., Rozycki, M., and Edelstein, S. (1996) Protein Methods. Wiley, New York.Google Scholar
- 6.Harlow, E. and Lane, D. (1988) Antibodies. A Laboratory Manual. Cold Spring Harbor Press, Cold Spring Harbor, NYGoogle Scholar