These in vitro findings support that ROS regulate the immune response by stimulating the antigen-presenting ability of glial cells and functioning as costimulatory molecules for antigen presentation.
Background
Previous studies have demonstrated that isoflurane can provide both neuroprotection and neurotoxicity in various tissue culture models and in rodent developing brains. The cellular and molecular mechanisms mediating these dual effects are not clear, but the exposure level and duration of isoflurane appear to be determinant factors.
Methods
Using the ReNcell CX human neural progenitor cell line, we investigated the impact of prolonged exposure to varying isoflurane concentrations on cell survival and neurogenesis. In addition, we assessed the impact of short isoflurane preconditioning on elevation of cytosolic Ca2+ concentration and cytotoxic effects mediated by prolonged isoflurane exposures and the contribution of InsP3 or ryanodine receptors activation to these processes.
Results
Short exposures to low isoflurane concentrations promote proliferation and differentiation of ReNcell CX cells, with no cell damage. However, prolonged exposures to high isoflurane concentrations induced significant ReNcell CX cell damage and inhibited cell proliferation. These prolonged exposures suppressed neuronal cell fate, while promoting glial cell fate. Preconditioning of ReNcell CX cultures with short exposures to low concentrations of isoflurane ameliorated the effects of prolonged exposures to isoflurane. Pretreatment of ReNcell cultures with InsP3 or ryanodine receptor antagonists mostly prevented isoflurane-mediated effects on survival, proliferation, and differentiation. Finally, isoflurane preconditioned cultures showed significantly less isoflurane-evoked changes in calcium concentration.
Conclusion
The commonly used general anesthetic isoflurane exerts dual effects on neuronal stem cell survival, proliferation and differentiation, which may be attributed to differential regulation of calcium release through activation of endoplasmic reticulum localized InsP3 and/or ryanodine receptors.
In a previous study, we demonstrated that immunization with the uveitogenic peptide interphotoreceptor retinoid-binding protein (IRBP) 1–20 induces both CD4 and CD8 uveitogenic T cells in the B6 mouse. In the current study, we determined the role of the CD8 IRBP-specific T cells in the pathogenesis of experimental autoimmune uveitis. We also determined the conditions that facilitated the activation of CD8 autoreactive T cells. Our results showed that the β2-microglobulin−/− mouse had a greatly decreased susceptibility to induction of experimental autoimmune uveitis by adoptive transfer of IRBP-specific T cells from B6 mice. We also showed that unlike CD4 autoreactive T cells, activated CD8 autoreactive T cells produced only a limited number and amounts of growth factors. As a result, in the absence of exogenously supplied growth factor(s), CD8 T cell activation and expansion were aborted. However, the growth and expansion of triggered CD8 autoreactive T cells could be supported by various cytokines. In addition to factors produced by activated CD4 autoreactive T cells, factors produced by nonlymphoid cells, such as IL-7 and IL-15, and unidentified factors in the culture supernatants of astrocytes and retinal pigment epithelial cells support the CD8 autoreactive T cells as well. Finally, we showed that, although several cytokines augmented the CD8 T cell response in vitro, different cytokines appeared to act on different CD8 subsets or on different activation/differentiation phases of CD8 autoreactive T cells. As a result, cytokines, such as IL-7, supported the proliferation and survival of CD8 IRBP-specific T cells, while others had only a growth-promoting effect.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.