Myosin V and iNOS expression is enhanced in J774 murine macrophages treated with IFN-gamma

Abstract

Actin-based motor protein requirements and nitric oxide (NO) production are important features of macrophage activity during phagocytosis or microbicidal processes. Different classes of myosins contribute directly or indirectly to phagocytosis by providing mechanical force for phagosome closure or organelle movement. Recent data have shown the presence of myosins IC, II, V and IXb in phagosomes of bone marrow-derived murine macrophages. In our investigation we demonstrated the presence of different classes of myosins in J774 macrophages. We also analyzed the effect of gamma interferon (IFNg), with or without calcium ionophore or cytochalasin B, on myosins as well as on inducible nitric oxide synthase (iNOS) expression and NO production. Myosins IC, II, Va, VI and IXb were identified in J774 macrophages. There was an increase of myosin V expression in IFNg-treated cells. iNOS expression was increased by IFN-g treatment, while calcium ionophore and cytochalasin B had a negative influence on both myosin and iNOS expression, which was decreased. The increases in NO synthesis were reflected by increased iNOS expression. Macrophages activated by IFN-g released significant amounts of NO when compared to control groups. In contrast, NO production by calcium ionophore-and cytochalasin B-treated cells was similar to that of control cells. These results suggest that IFN-g is involved in macrophage activation by stimulating protein production to permit both phagocytosis and microbicidal activity.

Defective Phagocytosis and Clearance of Pseudomonas aeruginosa in the Lung Following Bone Marrow Transplantation

“…6 demonstrate that levels of the activating cytokines, TNF-␣ and IFN-␥, are reduced within the alveolar space following P. aeruginosa infection as well. IFN-␥ has been reported to be important in mediating microbicidal activity (27)(28)(29), and diminished production of this protein is associated with defective killing of intracellular bacteria by both AMs and PMNs (30 -32). Our data suggest that impaired phagocytic function after BMT may be secondary to deficient production of IFN-␥ as well as TNF-␣, although the cellular source that is defective in this capacity (e.g., T cells, NK cells, or AMs) remains to be determined.…”

Localization of myosin-Va in subpopulations of cells in rat endocrine organs

“…d, e In maturing follicles, staining is seen in the granulosa cells (gc), including the corona radiata (cr) and cytoplasmic extensions in the zona pellucida (zp) in primary/secondary follicles, whereas in more advanced antral follicles (e), the corona radiata (cr) and zona pellucida (zp) do not stain. Oocytes (o) from maturing follicles show ooplasmic staining, most notably in the cortical (c) and perinuclear ooplasm (n nucleus) (Bizario et al 2002;Rodriguez and Cheney 2002) and macrophage cell line (Reis et al 2001).…”

Avaliação da Citotoxidade de Materiais Odontológicos Através do Método de MTT e Produção de Óxido Nítrico: Descrição de uma Técnica

“…Desta forma, a produção de NO em cultura de células pode ser estimada através do acúmulo do nitrito (NO2), que é o produto de conversão estável do óxido nítrico. Esta mensuração pode ser realizada através de um ensaio colorimétrico para NO, conhecido como método de Griess 28,29 . O aspecto visual também é imediato.…”