Cytotoxicity and Autophagy Induced by Ivermectin via AMPK/mTOR Signaling Pathway in RAW264.7 Cells

Bone marrow mesenchymal stem cell-derived extracellular vesicles alleviate diabetes-exacerbated atherosclerosis via AMPK/mTOR pathway-mediated autophagy-related macrophage polarization

INTRODUCTION

Bone marrow-derived mesenchymal stem cell-derived extracellular vesicles (BMSC-EVs) are widely used for therapeutic purposes in preclinical studies. However, their utility in treating diabetes-associated atherosclerosis remains largely unexplored. Here, we aimed to characterize BMSC-EV-mediated regulation of autophagy and macrophage polarization.

METHODS

EVs were isolated from the supernatant of cultured BMSCs and characterized with transmission electron microscopy (TEM), nanoparticle tracking analysis (NTA), and western blotting. A diabetes-related atherosclerotic ApoE-/- mouse model was established through feeding with a high-fat diet (HFD) and streptozotocin (STZ). Histopathological analyses were carried out using Oil Red O, H&E, and Masson staining of the aorta. TEM and immunohistochemistry (IHC) were applied to evaluate autophagy, and immunofluorescence (IF) was used to identify macrophage polarization. RAW264.7 macrophages were induced with oxidized low-density lipoprotein (ox-LDL) and high glucose (HG), co-cultured with BMSC-EVs, and analyzed for macrophage proliferation, migration, and foam cell formation. RAW264.7 cells were transduced with autophagy marker mRFP-GFP-LC3 lentivirus and analyzed with IF and western blotting.

RESULTS

Diabetic mice (DA group) had larger aortic plaque areas and lower collagen content than the HFD mice. BMSC-EV treatment significantly reduced blood glucose, LDL levels, and aortic plaque areas while increasing collagen content. BMSC-EV-treated aortas contained a higher number of autophagosomes/autolysosomes, with increased expression of LC3BII correlating with decreased P62 levels and a lower proportion of M1 macrophages. In vitro, BMSC-EVs inhibited proliferation, migration, and foam cell formation in ox-LDL and HG-induced activated RAW264.7 cells. These effects were reversed by the autophagy blocker bafilomycin A1. Consistent with the in vivo findings, BMSC-EVs elevated levels of the autophagy-related protein LC3BII/I and decreased P62 in ox-LDL and HG-induced RAW264.7 cells. These cells also expressed the M1 macrophage markers CD86 and iNOS, but showed reduced expression of the M2 marker Arg-1. Further, BMSC-EVs decreased AMPKα and mTOR phosphorylation levels, which were blocked by the AMPK inhibitor compound C.

CONCLUSIONS

BMSC-EVs attenuate diabetes-exacerbated atherosclerosis by inhibiting vascular macrophage proliferation, migration, and foam cell formation via AMPK/mTOR signaling-regulated autophagy and macrophage polarization. BMSC-EVs thus hold promise as therapeutic agents for atherosclerosis.

Lycopene Regulates Macrophage Immune Response through the Autophagy Pathway Mediated by RIPK1

The effects of lycopene (LP) on macrophage immune responses were evaluated in this study. Compared with the control treatment, LP treatment significantly increased cell vitality, phagocytic activity, and chemokine production in RAW264.7 cells. Additionally, compared with the control treatment, 4 μM LP treatment significantly activated autophagy, enhanced mitochondrial membrane potential, and upregulated receptor-interacting protein kinase 1 (RIPK1), while necrostatin-1 significantly reversed these effects of LP. Furthermore, compared with that in the control group, RIPK1 was significantly upregulated in the 4 μM LP and 4 μM LP + spautin-1 groups, whereas p-mTOR levels were reduced. More importantly, compared with that in the control group, p62 was significantly downregulated, and Beclin1, LC3-II, and Atg7 were upregulated in the 4 μM LP group, while spautin-1 significantly reversed these effects of LP. These results confirm that LP activates the mTOR/Beclin1/LC3/p62 autophagy signaling pathway through RIPK1, thereby enhancing the immune response of macrophages.

Ivermectin induces nonprotective autophagy by downregulating PAK1 and apoptosis in lung adenocarcinoma cells

INTRODUCTION

LUAD (Lung adenocarcinoma), the most common subtype of lung carcinoma and one of the highest incidences and mortality cancers in the world remains still a substantial treatment challenge. Ivermectin, an avermectin derivative, has been traditionally used as an antiparasitic agent in human and veterinary medicine practice during the last few decades. Though ivermectin has been shown to be effective against a variety of cancers, however, there is few available data reporting the antitumor effects of ivermectin in LUAD.

METHODS

The effect of ivermectin on cell viability and proliferative ability of LUAD cells was evaluated using CCK-8 and colony formation assay. Apoptosis rate and autophagy flux were detected using flow cytometry based on PI/Annexin V staining and confocal laser scanning microscope based on LC3-GFP/RFP puncta, respectively. Western blotting experiment was conducted to verify the results of changes in apoptosis and autophagy. LUAD-TCGA and GEO databases were used to analyse the expression and predictive value of PAK1 in LUAD patients. Xenograft model and immumohistochemical staining were used for verification of the inhibitor effect of ivermectin in vivo.

RESULTS

Ivermectin treatment strikingly impeded the colony formation, and the viability of the cell, along with cell proliferation, and caused the apoptosis and enhanced autophagy flux in LUAD cells. In addition, ivermectin-induced nonprotective autophagy was confirmed by treating LUAD cells with 3-MA, an autophagy inhibitor. Mechanistically, we found that ivermectin inhibited PAK1 protein expression in LUAD cells and we confirmed that overexpression of PAK1 substantially inhibited ivermectin-induced autophagy in LUAD cells. Based on TCGA and GEO databases, PAK1 was highly expressed in LUAD tissues as compared with normal tissues. Furthermore, LUAD patients with high PAK1 level have poor overall survival. Finally, in vivo experiments revealed that ivermectin efficiently suppressed the cellular growth of LUAD among nude mice.

CONCLUSION

This study not only revealed the mechanism of ivermectin inhibited the growth of LUAD but also supported an important theoretical basis for the development of ivermectin during the therapy for LUAD.

Autophagy Modulation and Its Implications on Glioblastoma Treatment

Autophagy is a vital cellular process that functions to degrade and recycle damaged organelles into basic metabolites. This allows a cell to adapt to a diverse range of challenging conditions. Autophagy assists in maintaining homeostasis, and it is tightly regulated by the cell. The disruption of autophagy has been associated with many diseases, such as neurodegenerative disorders and cancer. This review will center its discussion on providing an in-depth analysis of the current molecular understanding of autophagy and its relevance to brain tumors. We will delve into the current literature regarding the role of autophagy in glioma pathogenesis by exploring the major pathways of JAK2/STAT3 and PI3K/AKT/mTOR and summarizing the current therapeutic interventions and strategies for glioma treatment. These treatments will be evaluated on their potential for autophagy induction and the challenges associated with their utilization. By understanding the mechanism of autophagy, clinical applications for future therapeutics in treating gliomas can be better targeted.