The role of autophagy in the expression of proinflammatory cytokines in THP-1 cells
Abstract
Introduction: Autophagy is a process that cells use to eliminate old, unused, and damaged cytoplasmic components. The interaction between autophagy and cytokines could be one of the mechanisms that coordinate the activity of the innate and adaptive immune systems. Depending on the cell type and activation pathway, autophagy and pro-inflammatory cytokines have different mutual effects. Understanding the balance between these two processes is necessary to realize the therapeutic potential of autophagy regulation in various infectious, inflammatory, and autoimmune diseases.
The aim: The aim was to investigate the role of pharmacological modulation of autophagy on the expression of mRNA for the proinflammatory cytokines TNF, IL-1, and IL-6 in the monocytic cell line THP-1.
Material and methods: The pharmacological modulation of autophagy by bafilomycin and trehalose was determined by measuring the autophagic flux, the conversion of LC3-II after blocking its degradation, by the immunoblot method. LC3 represents a marker of autophagy and LC3-II levels are thought to correlate with the number of autophagosomes. Using the RT-qPCR, it was determined how bafilomycin and trehalose affect the expression of the pro-inflammatory cytokines TNF, IL-1, and IL-6 by modulating autophagy, by measuring the mRNA concentrations of these cytokines. Statistical analysis was performed using the GraphPad Prism program and the t test was used.
Results: Immunoblot analysis confirmed that bafilomycin blocks autophagic flux by increasing intracellular levels of LC3-II. Trehalose increased the level of LC3-II, both in the presence and absence of bafilomycin, inducing LC3-II conversion in THP-1 cells. RT-qPCR analysis of THP-1 cells treated with trehalose showed a significant increase in expression, and in those treated with bafilomycin, a significant decrease in the expression of mRNA for the cytokines TNF, IL-1, and IL-6.
Conclusion: Based on the results obtained in this research, it can be concluded that autophagy activates the expression of pro-inflammatory cytokines by incresaing the transcription of their genes.
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