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Cyclosporin a modulation of tumor necrosis factor gene expression and effects in vitro and in vivo
D T Nguyen1, M K Eskandai, L E DeForge
1Department of Pathology, University of Michigan Medical School, Ann Arbor 48109-0602.
Abstract:
We investigated, in vitro and in vivo, the cyclosporin A (CsA) regulation of LPS-induced TNF gene expression and subsequent pathophysiologic changes. In vitro dose-response kinetics data showed that CsA inhibited TNF bioactivity in the supernatant without delaying its production, whereas Northern blot and in situ hybridization analysis demonstrated that CsA did not inhibit TNF mRNA expression. We then sought to examine the in vivo effects of CsA (75 mg/kg) in CBA/J mice that were primed with CFA, and injected 2 wk later with LPS. CsA demonstrated suppression of local levels (ascites) of TNF as measured by either bioactivity or an anti-murine TNF ELISA. However, CsA did not decrease mRNA for TNF, or cell-associated TNF. In vivo kinetics studies were performed to show that CsA blocked both local (ascites) and systemic (plasma) LPS-induced TNF production without delaying these effects. CsA inhibited the neutrophilia and lymphopenia that developed after the LPS challenge, but did not block the lung neutrophilic infiltrate. These observations are helpful in understanding the role of the macrophage in CsA immunosuppression, particularly with regard to the ability of CsA to block LPS-induced TNF secretion.
Insights
Cyclosporin A (CsA) inhibits lipopolysaccharide (LPS)-induced tumor necrosis factor (TNF) bioactivity, but not its mRNA expression, in vitro and in vivo. CsA suppresses LPS-induced TNF secretion and related immune cell changes.
Area of Science:
- Immunology
- Pharmacology
- Molecular Biology
Background:
- Tumor necrosis factor (TNF) plays a critical role in inflammatory and immune responses.
- Cyclosporin A (CsA) is an immunosuppressive drug with complex mechanisms of action.
- Lipopolysaccharide (LPS) is a potent activator of immune cells, inducing TNF production.
Purpose of the Study:
- To investigate the effect of Cyclosporin A (CsA) on lipopolysaccharide (LPS)-induced TNF gene expression and secretion.
- To elucidate the role of CsA in modulating LPS-induced pathophysiological changes.
- To understand the impact of CsA on macrophage function in immunosuppression.
Main Methods:
- In vitro and in vivo experiments were conducted.
- Dose-response kinetics, Northern blot, and in situ hybridization were used to analyze TNF mRNA expression.
- Bioactivity assays and ELISA were employed to measure TNF levels.
- In vivo studies in mice assessed systemic and local TNF production and immune cell responses.
Main Results:
- In vitro, CsA inhibited TNF bioactivity but not TNF mRNA expression.
- In vivo, CsA suppressed local and systemic TNF levels and bioactivity without affecting mRNA or cell-associated TNF.
- CsA treatment blocked LPS-induced neutrophilia and lymphopenia but not lung neutrophilic infiltration.
Conclusions:
- Cyclosporin A (CsA) primarily inhibits the secretion of tumor necrosis factor (TNF) rather than its gene expression.
- CsA's immunosuppressive effects involve the blockade of LPS-induced TNF secretion.
- These findings contribute to understanding CsA's mechanism in modulating macrophage-mediated immune responses.