Role for complement in mediating intestinal nitric oxide synthase-2 and superoxide dismutase expression

Abstract

. Role for complement in mediating intestinal nitric oxide synthase-2 and superoxide dismutase expression. Am J Physiol Gastrointest Liver Physiol 285: G197-G206, 2003. First published March 13, 2003 10.1152/ajpgi.00029.2003.-Inducible nitric oxide synthase (iNOS) and superoxide dismutase (SOD) play an important role in the pathology of ischemia-reperfusion. This study sought to determine if the proinflammatory effects of complement modulate iNOS and SOD in the rat after gastrointestinal ischemia and reperfusion (GI/R). An inhibitory or noninhibitory anti-complement component 5 (C5) monoclonal antibody (18A or 16C, respectively) was administered before GI/R. RT-PCR revealed a significant increase in intestinal iNOS mRNA compared with sham after GI/R that was attenuated significantly by 18A. Immunohistochemistry demonstrated increased iNOS protein expression within the intestinal crypts after GI/R. Cu/Zn SOD (mRNA and protein) was unaffected by GI/R, whereas Cu/Zn SOD activity was reduced significantly. Mn SOD protein expression was decreased significantly by GI/R. Anti-C5 preserved Cu/Zn SOD activity and Mn SOD protein expression. Staining for nitrotyrosine showed that anti-C5 treatment reduced protein nitration in the reperfused intestine. Immunohistochemistry demonstrated prominent phosphorylated (p) inhibitory factor-B (I B)-␣ staining of intestinal tissue after GI/R, whereas anti-C5 reduced p-I B-␣ expression. These data indicate that complement may mediate tissue damage during GI/R by increasing intestinal iNOS and decreasing the activity and protein levels of Cu/Zn SOD and Mn SOD, respectively. ischemia-reperfusion; inhibitory factor-B; interleukin-1␤ GASTROINTESTINAL ISCHEMIA-reperfusion (GI/R) is a common clinical problem in the settings of sepsis, hemorrhagic shock, vascular surgery, and small bowel transplantation (17, 21). GI/R causes gut dysfunction characterized by histological evidence of impaired gut motility, increased intestinal permeability, and mucosal injury (18). Numerous mediators have been implicated in GI/R injury, including cytokines (8,15,43,54,55) NF-B is maintained in a latent form in the cytoplasm of cells where it is complexed to inhibitory factor-B (I B) proteins (24). Upon activation of NF-B, I B is phosphorylated (p) by I B kinases at two conserved serine residues in the NH 2 terminus, which targets the protein for ubiquination and degradation by the proteosome. This rapidly frees NF-B to translocate to the nucleus, where it upregulates the transcription of a variety of adhesion molecules (ICAM-1 and VCAM-1), cytokines (TNF, IL-1, and IL-6), and enzymes (iNOS; see Refs. 24 and 37).NO has been implicated as a mediator of tissue damage in several models of intestinal disease, including reperfusion injury (26,47,48). NO can be produced by three nitric oxide synthase (NOS) isoforms (neuronal NOS, iNOS, and endothelial NOS). Specific inhibition of iNOS has been shown to attenuate NO production significantly and decrease intestinal injury, indicating that iNOS mediates the excessive p...

Anti-inflammatory properties ofLactobacillus gasseriexpressing manganese superoxide dismutase using the interleukin 10-deficient mouse model of colitis

“…Each gene analyzed was normalized with Gapdh, yielding a relative transcript level. Gapdh has been previously used to normalize oxidative stress related genes in different organs in the mouse (2,20,42).…”

The complement system in ischemia–reperfusion injuries

“…The initial ischemic period results in cellular changes that alter subsequent signaling pathways and molecular expression (Montalto et al, 2003; Wada et al, 2001; Liangos et al, 2010). Glycolysis provides adenosine triphosphate, which during ischemia becomes depleted, and results in increased lactic acid formation and a decrease in pH.…”

Methylthioninium chloride: pharmacology and clinical applications with special emphasis on nitric oxide mediated vasodilatory shock during cardiopulmonary bypass

“…Complement C3a and C5a have been shown to depress myocardial function in animal models [123, 124], and human studies have demonstrated strong associations between plasma concentration of C3a and postoperative myocardial dysfunction [110, 120]. Complement activation also increases the gene translation and expression of iNOS [125, 126], thus contributing to the increased NO production and vasodilation associated with vasoplegic syndrome. Additional vasoactive chemokines are released from complement‐mediated mast cell degranulation causing increased vascular permeability [114] and stimulation of the release of proteases from activated leucocytes [127].…”