dre-miR-223/IKKα/NF-κB promotes inflammatory response in zebrafish liver (ZFL) cells induced by microcystin-LR.

Microcystin-LR (MC-LR) is the most prevalent and toxic microcystin congeners. Various studies have provided clear evidence that MC-LR is capable of inducing hepatic inflammation; however, the mechanisms remain incompletely elucidated. In this study, the inflammatory reaction induced by MC-LR and the underlying mechanisms in zebrafish liver (ZFL) cells were investigated. The results demonstrated that MC-LR could penetrate ZFL cells and inhibit cellular activity. Moreover, MC-LR exposure elevated the level of inflammation-related markers, including IL-1β, TNF-α, IL-6, and IL-10, promoted nuclear translocation of NF-κB p65, and upregulated dre-miR-223 expression, suggesting that MC-LR may trigger an inflammatory reaction in ZFL cells via activation of the NF-κB pathway, with dre-miR-223 may participating in this regulatory process. Further functional experiments using synthetic dre-miR-223 mimics and inhibitors showed that overexpression of dre-miR-223 significantly elevated the expression levels of IL-1β and TNF-α, whereas inhibition of dre-miR-223 led to a marked decrease in these cytokines compared to those induced by MC-LR alone, indicating that dre-miR-223 enhances the MC-LR-induced inflammatory reaction through the positive regulation of pro-inflammatory cytokine production. Dual-luciferase reporter assays combined with functional analyses further revealed that dre-miR-223 directly targets IKKα, a key component of the NF-κB pathway, thereby modulating the inflammatory response. The findings of this study are crucial for understanding the inflammatory mechanisms triggered by MC-LR exposure in fish and for evaluating the associated health risks.