Pyroptosis is a gasdermin-mediated pro-inflammatory form of programmed cell death (PCD). Tumor necrosis factor-ɑ (TNF-ɑ) is an inflammatory cytokine, and some studies have shown that TNF-ɑ can cause pyroptosis of cells and exert anti-tumor effects. However, whether TNF-ɑ exerts anti-tumor effects on breast cancer cells by inducing pyroptosis has not been reported. In this study, to explore the impact of TNF-ɑ on pyroptosis in breast cancer cells, we treated MCF-7 cells with TNF-ɑ and found that TNF-ɑ induced cell death. Moreover, we observed that the dead cells were swollen with obvious balloon-like bubbles, which was a typical sign of pyroptosis. Further studies have found that the anti-tumor effect of TNF-ɑ on breast cancer cells in vitro was achieved through the canonical pyroptosis pathway. In addition, TNF-ɑ-induced pyroptosis in MCF-7 cells was associated with mitochondrial dysfunction, in which mitochondrial membrane potential was decreased and mitochondrial ROS production was increased. After inhibiting ROS production, the activation effect of TNF-ɑ on NLRP3/Caspase-1/GSDMD pathway was weakened, and the inhibitory effect of TNF-ɑ on the growth of MCF-7 cells in vitro was also decreased, further confirming the involvement of ROS in TNF-ɑ-induced pyroptosis. Overall, our study revealed a new mechanism by which TNF-ɑ exerts an anti-tumor effect by inducing pyroptosis in MCF-7 cells through the ROS/NLRP3/Caspase-1/GSDMD pathway, which may provide new therapeutic ideas for the treatment of breast cancer.
Objective Inflammatory stimuli compromise the differentiation potency of human periodontal ligament cells (hPDLCs). Macrophage-derived exosomes (M-Exo) play a role in several aspects of cellular activity. This study investigated how M-Exo contributes to the osteo-/cementogenic differentiation of hPDLCs under inflammation and the mechanism involved. Methods M-Exo was identified by transmission electron microscopy, western blotting (WB), and dynamic light scattering. The internalization of M-Exo by hPDLCs was observed. After M-Exo treatment, the osteo-/cementogenic markers were detected by RT-qPCR and WB, and alkaline phosphatase (ALP) activity by ALP staining. Tumor necrosis factor alpha (TNF-ɑ) was applied to simulate inflammation. The rescue effect of M-Exo on TNF-ɑ-suppressed differentiation was validated. The p38 MAPK pathway activity was tested and a specific inhibitor was applied to explore the mechanism. Results M-Exo was successfully isolated, identified and internalized by hPDLCs. M-Exo enhanced the osteo-/cementogenic differentiation of hPDLCs, as indicated by upregulated osteo-/cementogenic markers and elevated ALP activity. Moreover, TNF-ɑ inhibited the differentiation capabilities of hPDLCs, on which M-Exo showed a rescue effect. M-Exo activated the p38 MAPK pathway and SB203580 attenuated its promotion effect. Conclusion This study showed that M-Exo ameliorated the TNF-ɑ-suppressed osteo-/cementogenic differentiation of hPDLCs partly through the p38 MAPK pathway.
The current treatments used in inflammatory bowel disease (IBD) therapy have significant side effects. Thus, it is very necessary to position and release TNF-α siRNA in inflamed tissues. Here, we demonstrate that poly(lactic- co -glycolic acid) can pack TNF-α siRNA efficiently into nanoparticles (NPs), and galactosylated chitosan (GC) can be grafted onto the NP surface, improving the RAW 264.7 macrophage-targeting kinetics of the NPs in vitro. Next, we orally administered GC-modified NPs loaded with TNF-α siRNA to C57BL/6 mice treated with 3% dextran sodium sulfate (DSS) to investigate their use in the treatment of colitis . When TNF-α siRNA loaded NPs were released into the colitis tissues of mice, GC-modified NPs (GPNs) alleviated the inflammation more efficiently than unmodified PGLA NPs (PNs). A series of colitis parameters (e.g., weight loss, myeloperoxidase (MPO) activity) demonstrated that GPNs have better anti-inflammatory effects than PNs. As indicated by flow cytometry, grafting GC onto NPs increased the macrophage uptake capacity and improved the kinetics of endocytosis. Collectively, our findings indicate that GC- modified TNF-α siRNA loaded NPs are powerful and efficient nanoscale materials for the delivery of therapeutic molecules to colitis tissues.
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