Evidence that glutamine is involved in neutrophil function

Abstract

Phosphate-dependent glutaminase (PDG) activity, a key enzyme of glutamine metabolism, was determined in neutrophils obtained from the intra-peritoneal cavity (PC) or bronchoalveolar space (BAS) after administration of 1 ml or 100 microl, respectively of saline, glycogen solution (1%) or lipopolysaccharide (LPS 0.1 mg (100 microl)(-1)). Neutrophils were obtained by lavage of both sites with 20 ml saline 24 h after the administration of the stimuli. Glycogen and LPS, depending on the site the cells were obtained from, differently modulated PDG activity. Cells from BAS stimulated by glycogen or LPS had raised PDG activity to 30.5 +/- 5.2 and 42.7 +/- 12.1 nmol min(-1) mg(-1) protein, respectively, when compared with saline (9.1 +/- 0.9 nmol min(-1) mg(-1) protein); mean +/- SEM. On the other hand, cells from PC showed different PDG activity: 52.0 +/- 12.6 nmol min(-1) mg(-1) for saline, 36.5 +/- 9.5 nmol min(-1) mg(-1) for glycogen, and 76.6 +/- 11.2 nmol min(-1) mg(-1) for LPS; mean +/- SEM. Therefore, PDG activity varies with the site from which neutrophils are obtained and the stimulus imposed. The effect of glutamine on nitric oxide (NO) and tumour necrosis factor (TNF) production by peritoneal neutrophils, obtained after glycogen administration, cultured in the presence of LPS (0.5 microg ml(-1)) was also examined. The addition of glutamine at concentrations varying from 2 to 20 mM did not markedly affect NO production. Glutamine alone at 2 mM did not modify the production of TNF but in the presence of LPS caused a significant decrease. So, glutamine may preserve the function of neutrophils during infections and injuries.

Glucose and glutamine utilization by rat lymphocytes, monocytes and neutrophils in culture: a comparative study

“…27 Glutamine upregulates the expression of the components of NADPH oxidase complex in rat neutrophils. 28 These findings explain the fact that glutamine enhances the bactericidal function of neutrophils from normal patients and those suffering from burns. [1][2][3] Recently, we have found that glutamine delays the onset of apoptosis in rat and human neutrophils.…”

“…[1][2][3] Recently, we have found that glutamine delays the onset of apoptosis in rat and human neutrophils. [28][29] Since glutamine metabolism provides NADPH/NADH to maintain the redox state of the cells and to ensure the production of ATP and intermediates for the synthesis of macromolecules such as nucleic acids and lipids, 30 a high glutamine consumption could be a metabolic attempt to preserve the integrity and function of the cells. 11,29 A moderate decrease in ATP level leads to apoptosis whereas a marked decrease of this nucleotide causes necrosis.…”

Diabetes causes marked changes in function and metabolism of rat neutrophils

“…The cell suspension was centrifuged at 4 C (500 g for 10 min). The number of viable cells (>95% neutrophils) was determined in a Neubauer chamber under an optical microscope by Trypan blue exclusion (Pires de Melo et al 1998, Pithon-Curi et al 2002.…”

Glutamine‐dependent changes in gene expression and protein activity

“…39 The production of TNF-was shown to be reduced by glutamine (2 mM) in cultured neutrophils stimulated with LPS. 41 Glutamine at concentrations of 4 and 10 mM leads to significant reduction of TNFexpression and release after lipopolysaccharide (LPS) treatment in cultured mononuclear cells. 42 This effect of glutamine treatment was accompanied by stimulated expression of HSP 72 in a dose-dependent fashion.…”