Mitochondria are key cellular organelles and play vital roles in energy metabolism, apoptosis regulation and cellular homeostasis. Mitochondrial dynamics refers to the varying balance between mitochondrial fission and mitochondrial fusion that plays an important part in maintaining mitochondrial homeostasis and quality. Mitochondrial malfunction is involved in aging, metabolic disease, neurodegenerative disorders, and cancers. Mitophagy, a selective autophagy of mitochondria, can efficiently degrade, remove and recycle the malfunctioning or damaged mitochondria, and is crucial for quality control. In past decades, numerous studies have identified a series of factors that regulate mitophagy and are also involved in carcinogenesis, cancer cell migration and death. Therefore, it has become critically important to analyze signal pathways that regulate mitophagy to identify potential therapeutic targets. Here, we review recent progresses in mitochondrial dynamics, the mechanisms of mitophagy regulation, and the implications for understanding carcinogenesis, metastasis, treatment, and drug resistance.
Background: The total flavones of Abelmoschus manihot (TFA), a compound that is extracted from Abelmoschus manihot, has been widely used in China to reduce podocyte injury in diabetic kidney disease (DKD). However, the mechanisms underlying the therapeutic action of this compound have yet to be elucidated. Podocyte pyroptosis is characterized by activation of the NLRP3 inflammasome and plays an important role in inflammation-mediated diabetic kidneys. Regulation of the PTEN/PI3K/Akt pathway is an effective strategy for improving podocyte damage in DKD. Previous research has also shown that N6-methyladenosine (m6A) modification is involved in DKD and that m6A-modified PTEN regulates the PI3K/Akt pathway. In this study, we investigated whether TFA alleviates podocyte pyroptosis and injury by targeting m6A modification-mediated NLRP3-inflammasome activation and PTEN/PI3K/Akt signaling.Methods: We used MPC-5 cells under high glucose (HG) conditions to investigate the key molecules that are involved in podocyte pyroptosis and injury, including activation of the NLRP3 inflammasome and the PTEN/PI3K/Akt pathway. We detected alterations in the levels of three methyltransferases that are involved in m6A modification. We also investigated changes in the levels of these key molecules in podocytes with the overexpression or knockdown of methyltransferase-like (METTL)3.Results: Analysis showed that TFA and MCC950 protected podocytes against HG-induced pyroptosis and injury by reducing the protein expression levels of gasdermin D, interleukin-1β, and interleukin-18, and by increasing the protein expression levels of nephrin, ZO-1, WT1 and podocalyxin. TFA and 740Y-P inhibited activation of the NLRP3 inflammasome via the PI3K/Akt pathway by inhibiting the protein levels of NIMA-related kinase7, NLRP3, ASC, and caspase-1, and by increasing the protein expression levels of p-PI3K and p-Akt. TFA improved pyroptosis and injury in HG-stimulated podocytes by regulating METTL3-dependent m6A modification.Conclusion: Collectively, our data indicated that TFA could ameliorate pyroptosis and injury in podocytes under HG conditions by adjusting METTL3-dependent m6A modification and regulating NLRP3-inflammasome activation and PTEN/PI3K/Akt signaling. This study provides a better understanding of how TFA can protect podocytes in DKD.
Aim: To investigate the antitumor efficacy of microwave ablation combined with dendritic cell-derived exosomes (Dex) or dendritic cells (DC) in treating hepatocellular carcinoma using a tumor-bearing mouse model. Methods: We used a bilateral tumor-bearing mouse model treated with MWA, MWA þ DC (DC-combined group) or MWA þ Dex (Dex-combined group). Following tumor ablation on one side, the tumor volume on the contralateral side was monitored. The proportions of CD8 þ (cytotoxic) T cells and regulatory T (Treg) cells in the spleen were analyzed by flow cytometry, and the number of CD8 þ T cells and Treg cells in tumor sites was detected by immunohistochemistry. The concentration of interleukin-10 and interferon-c in plasma was identified using enzyme-linked immunosorbent assay. Results: The combination therapy significantly inhibited tumor growth compared with MWA monotherapy. In addition, the tumor immune microenvironment was significantly improved in HCC mice in the combination therapy groups compared to MWA group demonstrated by an increased number of CD8 þ T cells and a decreased number of Treg cells in tumor sites. A lower proportion of Treg cells were observed in the spleen in the combination therapy groups compared to MWA group. Moreover, the concentration of plasma IFN-c increased, and the concentration of plasma IL-10 decreased in the combination therapy groups compared to the MWA group. However, there was no statistical difference between the Dex-combined group and the DC-combined group in the comparisons mentioned above. Conclusions: Our results provide evidence that MWA combined with Dex can significantly inhibit tumor growth and improve the immune microenvironment compared to MWA alone. Furthermore, the immune-enhancing effect of Dex and DC was equivalent in our combination therapy strategy.
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