Conclusion
Our results demonstrated that MG might protect RAW264.7 cells from S. aureus-induced apoptosis and autophagy via inhibiting JNK/Bax-dependent signal pathway. Therefore, MG may be a potential agent against pathological cell damage induced by S. aureus infection.
Methods
The RAW264.7 cells were pretreated with MG, or pretreated with SP600125 or anisomycin synchronously, and then infected with S. aureus (MOI=100:1). The viability and proliferation status of RAW264.7 cells were detected by MTT and EdU assay. The relative expression of TNF-α, IL-6 and IL-10 protein was tested with ELISA. The levels of Bax, Bcl-2, caspase-3, c-Jun N-terminal kinase (JNK), extracellular-regulated protein kinase (ERK), p38, LC3, Beclin-1, p62, phosphorylated JNK, phosphorylated p38 and phosphorylated ERK in cells were detected by Western blotting. The apoptosis rate of RAW264.7 cells was analyzed by flow cytometric assay.
Purpose
Staphylococcus aureus (S. aureus) is an important bacterial pathogen, which creates infective inflammation to human being and animals. Mangiferin (MG) is one of the natural flavonoids with anti-inflammatory, anti-bacterial, and anti-oxidative properties. However, the anti-apoptosis and anti-autophagy of MG are unknown. Hence, this study was aimed to research the inhibition of MG on S. aureus-induced apoptosis and autophagy in RAW264.7 cells.
Results
The study showed that MG significantly attenuated RAW264.7 cells apoptosis and autophagy caused by S. aureus. MG alleviated S. aureus-induced apoptosis by down-regulating the protein level of active caspase-3 and Bax and up-regulating the level of Bcl-2. MG also inhibited S. aureus-induced autophagy via decreasing the protein level of LC3-II/LC3-I and Beclin-1 or increasing the protein expression of p62. This protective role was dependent on the up-regulation of JNK signal pathway, which was confirmed by using JNK agonist and inhibitor.