Related Experiment Videos
Interleukin-1 and interleukin-6 gene expression in human monocytes stimulated with Salmonella typhimurium porins
M Galdiero1, G Cipollaro de L'ero, G Donnarumma
1Department of Pathology, Prophylaxis and Food Care, Frederick II Naples University, School of Veterinary Medicine, Italy.
Abstract:
The aim of this study was to verify whether Salmonella typhimurium porins can affect the expression of interleukin-1 (IL-1) and interleukin-6 (IL-6) genes. Human monocytes were treated with porins, and total RNAs were analysed by Northern blotting to evaluate the expression of IL-1 alpha, IL-1 beta and IL-6 in both treated and untreated cell cultures. Porins induced a significant increase in IL-1 and IL-6 transcripts. This increase was related to the dose of porins, and it peaked 5 hr after treatment. The same results were obtained when polymyxin B was added to the porin preparation to eliminate eventual traces of lipopolysaccharide (LPS) associated with porins. The porins-mediated increase in interleukin transcripts did not require de novo protein synthesis, and it was because of the enhanced half-life of IL-1 and IL-6 mRNAs, rather an increased rate of gene transcription. These data suggest that porins may affect inflammatory and immunological responses by enhancing the expression of cytokine genes.
Insights
Salmonella typhimurium porins significantly increase interleukin-1 (IL-1) and interleukin-6 (IL-6) gene expression in human monocytes. This effect is dose-dependent and enhances mRNA stability, suggesting a role in immune responses.
Area of Science:
- Immunology
- Microbiology
- Molecular Biology
Background:
- Interleukin-1 (IL-1) and Interleukin-6 (IL-6) are key cytokines in inflammatory and immune responses.
- Bacterial porins are outer membrane proteins that can interact with host immune cells.
Purpose of the Study:
- To investigate the effect of Salmonella typhimurium porins on IL-1 and IL-6 gene expression in human monocytes.
- To determine the mechanism by which porins influence cytokine gene expression.
Main Methods:
- Human monocytes were treated with purified Salmonella typhimurium porins.
- Total RNA was analyzed using Northern blotting to quantify IL-1 alpha, IL-1 beta, and IL-6 mRNA levels.
- Polymyxin B was used to control for lipopolysaccharide (LPS) contamination.
Main Results:
- Porins significantly increased IL-1 and IL-6 transcripts in a dose-dependent manner, peaking at 5 hours post-treatment.
- The observed increase in cytokine transcripts was confirmed even when LPS was neutralized.
- The porin-mediated effect resulted from enhanced mRNA half-life rather than increased gene transcription.
Conclusions:
- Salmonella typhimurium porins can modulate the expression of IL-1 and IL-6 genes in human monocytes.
- Porins enhance cytokine gene expression by stabilizing IL-1 and IL-6 mRNAs.
- These findings suggest that bacterial porins play a role in modulating host inflammatory and immunological responses.