Inhibition of chemotaxis Ng-monomethyl-L-arginine: a role for cyclic GMP

Abstract

The metabolism of L-arginine to nitric oxide (NO) has been shown to be important for the effector functions of many cell types, including polymorphonuclear (PMN) leukocytes. Its effect appears to be mediated at least in part by NO stimulation of soluble guanylate cyclase. We evaluated the role of this pathway in two PMN effector functions: cell movement and microbial killing, using the competitive inhibitor of L- arginine conversion to NO, NG-monomethyl-L-arginine (NMA). We also evaluated the effect of additional L-arginine and dibutyryl cyclic guanosine monophosphate (cGMP) on any NMA-associated changes. Human peripheral blood neutrophils were used and the cells were incubated with and without NMA. Chemotaxis was evaluated using a 48-well micro- Boyden chamber. Microbial killing was evaluated using S aureus strains D2C and 502A. These studies demonstrated that chemotaxis to formyl- methionyl-leucyl-phenylalanine was markedly inhibited in NMA-treated cells. This inhibition could be overcome if L-arginine or dibutyryl cGMP were added with the NMA. In contrast, microbial killing of S aureus was unaffected by NMA. These observations support the hypothesis that the L-arginine metabolism to NO and its effect on the cGMP level may be important for the dynamic changes required for neutrophil chemotaxis.

Investigation of the role of nitric oxide and cyclic GMP in both the activation and inhibition of human neutrophils

“…In the neutrophil, several second messenger/signal transduction systems can become activated, and these may be involved in the regulation of a variety of neutrophil eector functions. It has been shown that fMLP-induced chemotaxis in human neutrophils results from a rise in cyclic GMP levels subsequent to the production of NO (Kaplan et al, 1989;Belenky et al, 1993). Such a role for NO has been supported by our results here where inhibition of NOS with L-NMMA (Figure 1a) and chemical antagonism of NO with the NO scavenger carboxy-PTIO (Akaike et al, 1993) (Figure 1b) inhibited fMLP-induced chemotaxis.…”

“…Through the stimulation of guanylyl cyclase, nitric oxide increases guanosine 3':5'-cyclic monophosphate (cyclic GMP) formation. Intracellular accumulation of cyclic GMP has been suggested to regulate neutrophil chemotaxis in vitro (Sandler et al, 1975;Smith & Ignarro, 1975;Stephens & Snyderman, 1982;Anderson et al, 1986;Kaplan et al, 1989). Consistent with these concepts, it has been shown that fMLP-mediated chemotaxis was decreased by an inhibitor of NOS, N G -monomethyl-Larginine (L-NMMA), and that exogenous cyclic GMP reversed this inhibition (Kaplan et al, 1989).…”

“…Intracellular accumulation of cyclic GMP has been suggested to regulate neutrophil chemotaxis in vitro (Sandler et al, 1975;Smith & Ignarro, 1975;Stephens & Snyderman, 1982;Anderson et al, 1986;Kaplan et al, 1989). Consistent with these concepts, it has been shown that fMLP-mediated chemotaxis was decreased by an inhibitor of NOS, N G -monomethyl-Larginine (L-NMMA), and that exogenous cyclic GMP reversed this inhibition (Kaplan et al, 1989). Furthermore, it has been shown that NOS inhibitors signi®cantly attenuate chemotaxis of unstimulated and primed human neutrophils in vitro and that these eects were speci®c and modulated by cyclic GMP (Belenky et al, 1993).…”

Interaction of nitric oxide synthase inhibitors and their D‐enantiomers with rat neutrophil luminol dependent chemiluminescence response

“…However, we observed that L-NAME and L-NMMA both inhibited the LCL response, suggesting the nonspecificity of these inhibitors. Concentrations of these two compounds used by us have also been used by many other investigators to study the involvement of NO in the functions of PMNLs (Kaplan et al, 1989;Kubes et al, 1991;Malawista et al, 1992;Belenky et al, 1993). Interestingly, Pou et al (1992) have demonstrated that brain NOS can generate superoxide radicals in the absence of L-arginine and that this response was found to be inhibited by the NOS inhibitor L-NAME.…”

“…Many workers have used analogues of L-arginine to demonstrate the role of NO in polymorphonuclear leukocyte (PMNL) functions such as free radical generation, chemotaxis, aggregation, adhesion and microbicidal activity (Kaplan et al, 1989;Rubanyi et al, 1991;Kubes et al, 1991;Malawista et al, 1992;Belenky et al, 1993). Recently inhibition of free radical generation from rat PMNLs by both endogenous and exogenous nitric oxide has been demonstrated by us (Seth et al, 1994).…”