Nitric oxide mediates distinct effects of various LPS chemotypes on phagocytosis and leukotriene synthesis in human neutrophils

Neutrophil Cellular Responses to Various Salmonella typhimurium LPS Chemotypes

“…The opsonization of zymosan with normal serum resulted in enhanced activation of LT synthesis in PMNLs (Fig.9). LPSpriming of neutrophils further increased LT synthesis, with the effect increasing in the order Re < S < Ra LPS, as we published recently (Zagryazhskaya, et al, 2010). 100 µM and 500 µM L-NAME decreased the specificity of LPS chemotypes (Zagryazhskaya, et al, 2010).…”

“…We determined the capacity of various LPS species to modulate superoxide anion (O2-) production measured as cytochrome c reduction, as well as ROS production measured as luminol-dependent chemiluminescence, in PMLNs prior to or without their activation by OZ. The most potent O2-production was detected in Ra-primed cells in which we observed approximately 5-fold increase in the production level detected in control cells (Zagryazhskaya et al, 2010). It is noteworthy that activation of the cells with OZ dramatically increased O2-generation in both LPS-primed and control cells, while relative values of the LPS effects were diminished.…”

“…We recently published a paper on the influence of various LPS differing in their chain length on NOS activity in opsonized zymosan stimulated human PMNLs. We observed significant difference between Re and Ra forms of S. Typhimurium LPS in the capacity to induce NO release: Re LPS was twice more potent than Ra LPS (Zagryazhskaya et al, 2010). It is known that LPS activates protein kinase C (PKC) in macrophages and PMNLs.…”

“…The antioxidant agent diphenileleiodonium (DPI) that inhibits NADPH oxidase-mediated ROS formation, and also inhibits other flavo-enzymes such as NO synthase and xanthine oxidase (Wind et al, 2010), did not affect LPS-induced PMNL attachment (data not shown). LPS-induced intracellular calcium concentration varied in the order Ra ≥ S > Re (Zagryazhskaya et al, 2010). Taking into account the slight sensitivity of PMNL attachment to NO synthesis inhibitors, we can propose that the divalent cation requirements for the Mac-1 and LFA-1-dependent processes of adhesion (Graham & Brown, 1991;Wright & Jong, 1986) may limit the role for NO and superoxide in the specificity of these LPS chemotypes in PMNL adhesion, in the serum-free medium.…”

Involvement of purinergic signaling on nitric oxide production by neutrophils stimulated with Trichomonas vaginalis

“…The involvement of NO in immune responses can be evidenced due its intense production after LPS stimuli, as observed in our study. The LPS is a potent agent in inflammatory process that promotes the NO fluxes as result of oxide nitric synthase activation, mainly due to the lipid A portion from LPS molecule [36]. Previous studies have investigated the NO role in immunity to trichomonosis.…”