<i>myc</i>‐Immortalized Microglial Cells Express a Functional Platelet‐Activating Factor Receptor

Righi, Marco; Letari, Ornella; Sacerdote, Paola; Marangoni, Franca; Miozzo, A.; Nicosia, S.

doi:10.1046/j.1471-4159.1995.64010121.x

Cited by 37 publications

(20 citation statements)

References 28 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The effect of BN 50730 on microglial PAFmediated events is unknown. At the intracellular level, PAF stimulates both calcium accumulation and immediate-early gene expression in microglia (23). Thus BN 50730 might be expected to block PAF-induced changes in gene transcription in microglia, as has already been demonstrated in neurons.…”

mentioning

confidence: 71%

Platelet-Activating Factor Antagonist BN 50730 Attenuates Hypoxic-Ischemic Brain Injury in Neonatal Rats

2001

View full text Add to dashboard Cite

Platelet-activating factor (PAF) is a lipid derived from breakdown of cell membranes that is postulated to be a mediator of cerebral ischemic injury. PAF regulates CNS gene transcription via intracellular binding sites. To test the hypothesis that PAF mediates CNS injury in part by modulating gene transcription, we evaluated the neuroprotective efficacy of the drug BN 50730, an antagonist of the intracellular (microsomal) CNS PAF binding site, in the neonatal rat model of unilateral cerebral hypoxiaischemia. Seven-day-old rats underwent right carotid ligation followed by a 2.5-h exposure to 8% O 2 , and were then treated with BN 50730 (2.5 or 25 mg/kg per dose) or vehicle, at 0 and 2 h after the end of hypoxia. Ipsilateral cortical, striatal, and hippocampal damage was quantitated either 5 d later, or at 5 wk after the insult. Treatment with BN 50730 resulted in approximately 60 -80% reduction in ipsilateral tissue loss at both times. Learning and memory were evaluated 5 wk after insult using the Morris Watermaze place navigation task. Severity of cortical and striatal damage correlated significantly with learning and memory deficits. These results support the hypothesis that PAF is a pathogenetic mediator of hypoxic-ischemic damage in the immature brain. Accumulating evidence suggests that PAF mediates its deleterious effects in the immature CNS via multiple mechanisms. PAF (1-O-alkyl-2-acetyl-sn-glycero-3-phosphocholine) is a potent phospholipid mediator with distinct systemic and CNS actions. In the CNS, PAF is synthesized in neurons and microglia (1, 2), and PAF receptors are expressed predominantly in neurons and microglia and, to a lesser extent, on astrocytes and CNS endothelium (3-5). PAF has distinct neuronal actions, as a synaptic messenger, a transcriptional activator, and a critical determinant of normal brain development (6, 7). In addition to these CNS effects, PAF has potent proinflammatory systemic effects (8). PAF accumulates in ischemic CNS tissue in mature and immature animals (9 -12). In mature animals, most reports indicate that PAF receptor antagonist treatment attenuates cerebral ischemic damage (13-16). Several recent studies implicate PAF as a mediator of ischemic injury in the neonatal brain (12, 17).Brain PAF concentrations rise acutely after neonatal cerebral hypoxia-ischemia (12), most likely as a result of breakdown of membrane phospholipids. Treatment with the PAF receptor antagonist BN 52021 (ginkgolide B), beginning either before or immediately after hypoxia exposure, reduced hypoxicischemic brain injury in postnatal d 7 rats (17). Pretreatment with a Ginkgo biloba extract, which includes BN 52021, attenuated posthypoxic-ischemic PAF accumulation (12). These results suggest that PAF contributes to the pathogenesis of neonatal cerebral hypoxic-ischemic injury.PAF could mediate cerebral hypoxic-ischemic injury via either of two distinct neuronal PAF binding sites. Studies in adult rat cerebral cortex subcellular membrane fractions delineate distinct populations of neuronal PAF bind...

show abstract

mentioning

confidence: 71%

Platelet-Activating Factor Antagonist BN 50730 Attenuates Hypoxic-Ischemic Brain Injury in Neonatal Rats

2001

View full text Add to dashboard Cite

show abstract

“…The first report of PAF inducing [Ca 2ϩ ] c signals in microglial cells appeared in 1995 (Righi et al, 1995). This study mainly characterized the PAF responses of a microglial cell line, but it also showed some evidence for PAF-induced [Ca 2ϩ ] c signals in mouse primary microglial cells.…”

Section: Platelet-activating Factor Receptorsmentioning

confidence: 84%

Calcium signaling in microglial cells

Möller

2002

Glia

View full text Add to dashboard Cite

Receptor-mediated Ca(2+) signals are a common signal transduction mechanism in all living cells, including microglia. Recent years have brought major advances in our understanding of microglial Ca(2+) signaling. More than 20 receptor/ligand interactions leading to Ca(2+) signals in microglia have been described so far, and it seems that this is just the beginning. The literature has grown rapidly during the past few years, especially in regard to chemokine and ATP/UTP receptor signaling. This article presents a brief overview of the basics of Ca(2+) signaling, reviews the current literature on microglial Ca(2+) signaling, and discusses the current challenges and possible future directions of this emerging field.

show abstract

“…The mouse microglial cell line N9 was a kind gift of Dr. M. Righi, International School for Advanced Studies, Trieste, Italy, and was cultured in accordance with the original publication (Righi et al, 1995). Briefly, cells were cultured in Dulbecco's Modified Eagle's Medium (DMEM; Mediatech, Herndon, VA), supplemented with 10% fetal bovine serum (FBS; Hyclone, Logan, UT) and penicillin/streptomycin (P/S, 50 I.U./50 μg/mL; Mediatech).…”

Section: Cell Culturementioning

confidence: 99%

Lipopolysaccharide is a frequent and significant contaminant in microglia‐activating factors

Weinstein

Swarts

Bishop

et al. 2007

Glia

View full text Add to dashboard Cite

Lipopolysaccharide (LPS/endotoxin) is a potent immunologic stimulant. Many commercial-grade reagents used in research are not screened for LPS contamination. LPS induces a wide spectrum of proinflammatory responses in microglia, the immune cells of the brain. Recent studies have demonstrated that a broad range of endogenous factors including plasma-derived proteins and bioactive phospholipids can also activate microglia. However, few of these studies have reported either the LPS levels found in the preparations used or the effect of LPS inhibitors such as polymyxin B (PMX) on factor-induced responses. Here, we used the Limulus amoebocyte lysate assay to screen a broad range of commercial-and pharmaceutical-grade proteins, peptides, lipids, and inhibitors commonly used in microglia research for contamination with LPS. We then characterized the ability of PMX to alter a representative set of factor-induced microglial activation parameters including surface antigen expression, metabolic activity/proliferation, and NO/cytokine/chemokine release in both the N9 microglial cell line and primary microglia. Significant levels of LPS contamination were detected in a number of commercial-grade plasma/ serum-and nonplasma/serum-derived proteins, phospholipids, and synthetic peptide preparations, but not in pharmaceutical-grade recombinant proteins or pharmacological inhibitors. PMX had a significant inhibitory effect on the microglia-activating potential of a number of commercial-, but not pharmaceutical-grade, protein preparations. Novel PMX-resistant responses to α 2 -macroglobulin and albumin were incidentally observed. Our results indicate that LPS is a frequent and significant contaminant in commercial-grade preparations of previously reported microgliaactivating factors. Careful attention to LPS levels and appropriate controls are necessary for future studies in the neuroinflammation field.

show abstract

myc‐Immortalized Microglial Cells Express a Functional Platelet‐Activating Factor Receptor

Cited by 37 publications

References 28 publications

Platelet-Activating Factor Antagonist BN 50730 Attenuates Hypoxic-Ischemic Brain Injury in Neonatal Rats

Platelet-Activating Factor Antagonist BN 50730 Attenuates Hypoxic-Ischemic Brain Injury in Neonatal Rats

Calcium signaling in microglial cells

Lipopolysaccharide is a frequent and significant contaminant in microglia‐activating factors

Contact Info

Product

Resources

About