Inducible nitric oxide synthase activity of cloned murine microglial cells

Abstract

Nitric oxide (NO) is a short-lived diffusable molecule now believed to participate in multiple physiologic functions in the CNS including neurotransmission and the maintenance of vascular tone. Previously, we reported that cell lines obtained by retroviral immortalization of tissue macrophages (M phi) could be induced to synthesize nitrite (NO2-), a stable end product of the NO synthetic pathway. We have further characterized the induction and activity of this pathway in a panel of seven microglial clones derived from primary embryonic mouse brain cultures. Like M phi, these clones were found to release high levels of NO2- in response to recombinant interferon-gamma (rIFN-gamma) as a priming signal together with either bacterial lipopolysaccharide (LPS) or exogenous recombinant tumor necrosis factor-alpha (rTNF-alpha). As previously demonstrated for M phi, phagocytosis of zymosan particles during induction of enzyme activity enhanced subsequent NO2- production, which is of interest in light of the postulated phagocytic role of microglia within the CNS. Biochemical characterization of enzyme activity in intact microglial clones and in isolated cytosolic fractions indicates that the microglial NO synthase present in these murine cell clones represents the M phi-like isotype. These findings suggest that microglial cells could represent a major source of NO within the CNS.

Liver X receptor and retinoid X receptor agonists inhibit inflammatory responses of microglia and astrocytes

“…These panning procedures were repeated, as necessary, to obtain primary microglia or astrocytes of greater than 95% purity as determined by immunocytochemical staining with lectin or anti-glial fibrilary acidic protein (GFAP) antibody, respectively. The N9 microglial cell line is derived from myc-immortalized mouse microglia (Corradin et al, 1993), and was graciously provided by P. Ricciardi-Castagnoli (U. Milan, Italy). N9 cells were cultured in MEM medium containing 10% FBS, 1.4 mM glutamine, and 20 μM 2-mercaptoethanol.…”

Peroxisome Proliferator-Activated Receptor-γ Agonist 15-Deoxy-Δ12,1412,14-Prostaglandin J2 Ameliorates Experimental Autoimmune Encephalomyelitis

“…The N9 microglial cell line is derived from myc-immortalized mouse microglia (38) and was provided by P. Ricciardi-Castagnoli (University of Milan, Milan, Italy). Cells were cultured in MEM containing 10% FBS (Sigma-Aldrich), 1.4 mM glutamine, and 20 M 2-ME (Sigma-Aldrich).…”

Microglial activation by uptake of fDNA via a scavenger receptor

“…The N9 mouse microglial cell line (Corradin et al, 1993) was maintained as previously described (Li et al, 2001). Microglial cells were seeded on culture dishes (Ф, 35 or 60 mm) for RNA assays, or grown on chambered slides (Nunc, Naperville, IL) for fluorescence microscopy.…”