Agarwood extract improves psoriatic-like inflammation in HaCaT cells by regulating NF-κB pathway

Objective To investigate the effect and mechanism of agarwood extract (AE) on tumor necrosis factor-α (TNF-α)-induced psoriatic-like inflammation model of keratinocytes (HaCaT).

Methods The psoriatic-like inflammation model of HaCaT cells was induced by 40 ng/mL TNF-α, and then the cells were treated with AE at concentrations of 16 μg/mL (low concentration), 24 μg/mL (medium concentration), 32 μg/mL (high concentration). Cell counting kit-8 (CCK-8) assay was used to detect the viability of HaCaT cells. Flow cytometry was applied to detect the apoptosis of HaCaT cells. Reverse transcription-quantitative polymerase chain reaction (RTqPCR) and enzyme-linked immunosorbent assay (ELISA) were used to detect the mRNA expression and secretion levels of various inflammatory mediators, as well as that of inhibitor kappa B alpha (IκBα). Western blotting was used to detect the expression of key proteins in the NF-κB pathway.

Results After 40 ng/mL TNF-α stimulation, the viability of HaCaT cells was increased (P < 0.01), the early apoptosis rate and IκBα mRNA level were decreased (P < 0.05), and the mRNA expression levels and release of interleukin-6 (IL-6), interleukin-1β (IL-1β), interleukin17A (IL-17A), TNF-α, chemokine ligand 20 (CCL20) in cells were increased (P < 0.05). The expres‐sion level of phosphorylated nuclear factor-κB p65 (p-p65) protein was increased (P < 0.01). After a certain concentration of AE intervention, the viability of HaCaT cells was decreased (P < 0.01). Treatment with low, medium and high concentrations of AE in TNF-α pretreated HaCaT cells increased the early apoptosis rate and the mRNA-expression level of IκBα (P < 0.01). Meanwhile, it decreased the mRNA expression and release of IL-6, IL-1β, IL-17A, TNF-α and CCL20 (P < 0.05), as well as the p-p65 protein level (P < 0.01).

Conclusion AE can inhibit the phosphorylation of p65 protein in the NF-κB pathway, thereby reducing the release of inflammatory factors and chemokines in the psoriatic-like inflammatory model of HaCaT cells, inducing apoptosis, and improving the inflammatory response.