Arginase activity in a murine macrophage cell line (RAW264.7) stimulated with lipopolysaccharide from Actinobacillus actinomycetemcomitans

Abstract

The results of the present study suggest that lipopolysaccharide from A. actinomycetemcomitans via CD14/toll-like receptor 4 complex molecules and the regulatory control of glucocorticoid and cytokines may stimulate arginase activity in RAW264.7 cells.

Sequential expression of macrophage anti-microbial/inflammatory and wound healing markers following innate, alternative and classical activation

“…While much of the literature defines argI expression as a hallmark of murine alternative activation [5,9,10,36,37], other studies describe argI expression or arginase activity in macrophages following LPS stimulation [12][13][14]38,39]. Further studies speculate that the ability of LPS to influence arginase is species-dependent [40].…”

“…For example, as the induction of arginase I can be mediated by IL-4/IL-13 in macrophages this enzyme has often been described as a marker for alternative activation [5,[8][9][10]. However, LPS, a potent inducer of innate activation through Toll-like receptor (TLR)-4 ligation, has also been shown in some studies to induce both isoforms of arginase in addition to NOS2 activity [11][12][13][14]. At the same time other studies also exist, suggesting that LPS is less capable than IL-4 of arginase induction [6,7].…”

Nitric oxide production by a human osteoblast cell line stimulated with Aggregatibacter actinomycetemcomitans lipopolysaccharide

“…Previous studies indicated that A. actinomycetemcomitans lipopolysaccharide binds to a CD14–TLR4 molecular complex on the surface of human gingival fibroblasts (10), murine dendritic cells (19), and murine macrophages (41). Indeed, the present results also showed that both iNOS activity and nitrite production by A. actinomycetemcomitans lipopolysaccharide‐stimulated HOS cells were dependent on the CD14–TLR4 molecular complex, suggesting that the binding between A. actinomycetemcomitans lipopolysaccharide and the CD14–TLR4 molecular complex on the surface of HOS cells may initiate the signal transduction leading to the production of NO.…”

The role of cyclic‐AMP on arginase activity by a murine macrophage cell line (RAW264.7) stimulated with lipopolysaccharide from Actinobacillus actinomycetemcomitans

“…Our previous study indicated that A. actinomycetemcomitans LPS stimulates arginase activity in a murine macrophage cell line (RAW264.7) (21). However, the exact intracellular signal(s) involved in the activation of this enzyme activity by A. actinomycetemcomitans ‐LPS‐stimulated RAW264.7 cells was not established.…”

“…It was speculated that IL‐4 might increase arginase activities in A. actinomycetemcomitans LPS‐activated murine macrophages (18, 19). Indeed, our previous study showed that A. actinomycetemcomitans LPS stimulated arginase activity in RAW264.7 cells via a CD14–Toll‐like receptor 4 molecule complex (21). In that study, arginase activity in A. actinomycetemcomitans LPS‐stimulated RAW264.7 cells was enhanced by IL‐4 but suppressed by IFN‐ γ , suggesting that arginase activity and nitric oxide synthase (NOS) in A. actinomycetemcomitans LPS‐stimulated RAW264.7 cells may be reciprocally regulated by T helper type1 (Th1) and Th2‐derived cytokines.…”