Effects of Jatrorrhizine on inflammatory response induced by HO in microglia by regulating the MAPK/NF-κB/NLRP3 signaling pathway.

Microglia-induced neuroinflammation is a contributing factor to neurodegenerative diseases. Jatrorrhizine (JAT), an alkaloid isolated from Huanglian, has been shown to have neuroprotective effects against various neurodegenerative diseases, but its impact on microglia-induced neuroinflammation remains unclear. In this study, we investigated the role of JAT in MAPK/NF-κB/NLRP3 signaling pathway in an HO-induced oxidative stress model using microglia (N9 cells). We divided cells into six groups, including control, JAT, HO, HO + 5 μmol/L JAT, HO + 10 μmol/L JAT, and HO + 20 μmol/L minocycline groups. Cell viability was measured using MTT assay and TNF-α levels were detected with an ELISA Kit. Western blot was used to detect NLRP3, HMGB1, NF-κB, p-NF-κB, ERK, p-ERK, p38, p-p38, p-JNK, JNK, IL-1β, and IL-18 expressions. Our results showed that JAT intervention improved HO-induced cytotoxicity in N9 cells and reduced the elevated expression of TNF-α, IL-1β, IL-18, p-ERK/ERK, p-p38/p38, p-JNK/JNK, p-p65/p65, NLRP3, and HMGB1 in HO group. Furthermore, treatment with ERK inhibitor SCH772984 specifically blocked ERK phosphorylation, resulting in decreased protein levels of p-NF-κB, NLRP3, IL-1β, and IL-18 in HO group. These results suggest that the MAPK/NF-κB signaling pathway may regulate the protein levels of NLRP3. Overall, our study indicates that JAT may have a protective effect on HO-treated microglia via inhibition the MAPK/NF-κB/NLRP3 pathway and could be a potential therapeutic approach for neurodegenerative diseases.