Palmitic Acid Induces Inflammatory Environment and Is Involved in Pyroptosis in a Human Dental Pulp Cell Line

TL;DR

This study shows that palmitic acid causes inflammation and pyroptosis in human dental pulp cells.

Contribution

The study demonstrates a novel link between palmitic acid exposure and pyroptosis in dental pulp cells.

Findings

Palmitic acid significantly reduced cell viability and altered cell morphology.

Palmitic acid increased RNA expression of IL-1β, IL-6, caspase-4, and gasdermin d.

Combining palmitic acid with LPS further increased inflammatory cytokine levels.

Abstract

Background/Objectives: We investigated whether palmitic acid (PA) induced the expression of inflammatory cytokines and was involved in pyroptosis in a human dental pulp cell line. Methods: Human dental pulp cells cultured in Minimum Essential Medium Alpha (αMEM) were treated with 1 µg/mL LPS and/or PA (100, 300 and 500 µM). As a control, αMEM was added in the culture medium. The WST-1 assay was performed to assess cell proliferation, and morphological changes in cells were examined. RNA expression of IL-1β, IL-6, TNF-α, caspase-4 and gasdermin d were detected by quantitative RT-PCR (qPCR). Results: The WST-1 assay showed that cell viability decreased by 36% at 300 µM and 47% at 500 µM PA compared to the control (p < 0.05). Cell morphology revealed slight shrinkage in 100, 300 and 500 µM PA groups. RNA expression of IL-1β and IL-6 in the PA groups was significantly higher than that in the control groups (p < 0.05), while RNA expression of TNF-α in the PA group was the same as that of control group. The mRNA expression of caspase-4 and gasdermin d in PA groups was significantly higher than that in control group (p < 0.05). Likewise, the concentration of IL-1β and IL-6 was significantly higher in both LPS and PA groups than that in the LPS or PA groups (p < 0.05). Conclusions: The results of this study suggest that PA induces the expression of inflammatory cytokines and is involved in pyroptosis in a human dental pulp cell line.

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