Xenophagy in cancer

Chinese Medicine for the Treatment of Liver Cirrhosis: The Mechanism of Cellular Autophagy

Liver cirrhosis is a critical stage in the progression of various chronic liver diseases, often leading to severe complications such as ascites, hepatic encephalopathy, and a high mortality rate, and it thus poses a serious threat to patient life. The activation of hepatic stellate cells is a central driver of disease progression. Cellular autophagy, a lysosome-mediated degradation process, plays a key role in maintaining cellular function and dynamic homeostasis. Research has shown that autophagy is closely associated with proteins like LC3, Beclin-1, P62, and mTOR, and is regulated through signaling pathways such as PI3K/Akt/mTOR, Ras/Raf/MEK/ERK, and AMPK/mTOR. Additionally, the relationship between autophagy and apoptosis, as well as between autophagy and exosomes, has been further demonstrated. While modern medicine has made progress in treating cirrhosis, it still faces significant limitations. By contrast, numerous studies have demonstrated the efficacy of traditional Chinese medicine in preventing and treating liver cirrhosis by regulating autophagy, with fewer adverse effects. Chinese herbal monomers and formulations can modulate various autophagy-related signaling pathways, including PI3K/Akt/mTOR, Ras/Raf/MEK/ERK, and AMPK/mTOR, and influence key autophagy proteins such as LC3 and Beclin-1. This modulation inhibits hepatic stellate cell activation, reduces extracellular matrix deposition, and exerts anticirrhotic effects. Moreover, Chinese medicine appears to reduce adverse reactions in cirrhosis treatment and lower the risk of disease recurrence. This review explores the mechanisms of autophagy in the prevention and treatment of liver cirrhosis through Chinese medicine, offering new insights for the development of Chinese medicinal therapies for cirrhosis and their rational clinical application.

αAsarone alleviates neuronal injury by facilitating autophagy via miR-499-5p/PDCD4/ATG5 signaling pathway in ischemia stroke

INTRODUCTION

αAsarone, an essential oil derived from Acorus gramineus Aiton, which has been successfully used to treat epilepsy in traditional chinese medicine, and has also been reported to confer neuroprotective effects on stroke. However, its mechanism of action remains poorly understood.

METHODS

The effects of αAsarone on autophagy were examined by WB, RT-qPCR, immunofluorescence colocalization, transmission electron microscope, and autophagic flux activity was measured by infecting HT22 cells with mRFP-GFP-LC3 adenovirus. And then, cells were transfected with both mimic-miR-499-5p and inhibit-miR-499-5p to investigate the role of miR-499-5p in regulating the effects of αAsarone on stroke. To further clarify the protective effect of αAsarone in vivo, TTC staining, neurological function score, H&E staining, Nissl staining, Laser speckle contrast imaging, transmission electron microscopy, immunofluorescence colocalization, WB and RT-qPCR were performed in the MCAO mice.

RESULTS

αAsarone was observed to inhibit the apoptosis of neuronal cells, and enhance autophagy. In addition, αAsarone promoted the expression of miR-499-5p. Targeting miR-499-5p can negatively regulate PDCD4 expression and the results from the dual-luciferase reporter assay demonstrate the direct targeting of PDCD4 by miR-499-5p. Promoting miR-499-5p can decrease the expression of PDCD4, increase ATG5, and enhance the protective effect of αAsarone on OGD/R injury while inhibiting miR-499-5p can weaken the effect of αAsarone. In vivo experiments further confirmed that αAsarone improved mice MCAO as evidenced by the amelioration of the neurological deficits and facilitated neuronal autophagy. Furthermore, we found that αAsarone reversed the effect of chloroquine, an autophagy inhibitor, and enhanced neuronal autophagy via miR-499-5p/PDCD4/ATG5 signaling pathway.

DISCUSSION

Our data suggest that αAsarone alleviates neuronal injury of stroke by facilitating neuronal autophagy through the miR-499-5p/PDCD4/ATG5 signaling pathway.

Polysaccharides targeting autophagy to alleviate metabolic syndrome

Metabolic syndrome is a prevalent non-communicable disease characterized by central obesity, insulin resistance, hypertension, hyperglycemia, and hyperlipidemia. Epidemiological statistics indicate that one-third of the world's population is affected by metabolic syndrome. Unfortunately, owing to complicated pathogenesis and limited pharmacological options, the growing prevalence of metabolic syndrome threatens human health worldwide. Autophagy is an intracellular degradation mechanism that involves the degradation of unfolded or aggregated proteins and damaged cellular organelles, thereby maintaining metabolic homeostasis. Increasing evidence indicates that dysfunctional autophagy is closely associated with the development of metabolic syndrome, making it an attractive therapeutic target. Furthermore, a growing number of plant-derived polysaccharides have been shown to regulate autophagy, thereby alleviating metabolic syndrome, such as Astragalus polysaccharides, Laminaria japonica polysaccharides, Ganoderma lucidum polysaccharides and Lycium barbarum polysaccharides. In this review, we summarize recent advances in the discovery of autophagy modulators of plant polysaccharides for the treatment of metabolic syndrome, with the aim of providing precursor compounds for the development of new therapeutic agents. Additionally, we look forward to seeing more diseases being treated with plant polysaccharides by regulating autophagy, as well as the discovery of more intricate mechanisms that govern autophagy.

Oxidative Stress and Cancer Therapy: Controlling Cancer Cells Using Reactive Oxygen Species

Cancer is a multifaceted disease influenced by various mechanisms, including the generation of reactive oxygen species (ROS), which have a paradoxical role in both promoting cancer progression and serving as targets for therapeutic interventions. At low concentrations, ROS serve as signaling agents that enhance cancer cell proliferation, migration, and resistance to drugs. However, at elevated levels, ROS induce oxidative stress, causing damage to biomolecules and leading to cell death. Cancer cells have developed mechanisms to manage ROS levels, including activating pathways such as NRF2, NF-κB, and PI3K/Akt. This review explores the relationship between ROS and cancer, focusing on cell death mechanisms like apoptosis, ferroptosis, and autophagy, highlighting the potential therapeutic strategies that exploit ROS to target cancer cells.

The significance of targeting lysosomes in cancer immunotherapy

Lysosomes are intracellular digestive organelles that participate in various physiological and pathological processes, including the regulation of immune checkpoint molecules, immune cell function in the tumor microenvironment, antigen presentation, metabolism, and autophagy. Abnormalities or dysfunction of lysosomes are associated with the occurrence, development, and drug resistance of tumors. Lysosomes play a crucial role and have potential applications in tumor immunotherapy. Targeting lysosomes or harnessing their properties is an effective strategy for tumor immunotherapy. However, the mechanisms and approaches related to lysosomes in tumor immunotherapy are not fully understood at present, and further basic and clinical research is needed to provide better treatment options for cancer patients. This review focuses on the research progress related to lysosomes and tumor immunotherapy in these.

Selective autophagy in cancer: mechanisms, therapeutic implications, and future perspectives

Eukaryotic cells engage in autophagy, an internal process of self-degradation through lysosomes. Autophagy can be classified as selective or non-selective depending on the way it chooses to degrade substrates. During the process of selective autophagy, damaged and/or redundant organelles like mitochondria, peroxisomes, ribosomes, endoplasmic reticulum (ER), lysosomes, nuclei, proteasomes, and lipid droplets are selectively recycled. Specific cargo is delivered to autophagosomes by specific receptors, isolated and engulfed. Selective autophagy dysfunction is closely linked with cancers, neurodegenerative diseases, metabolic disorders, heart failure, etc. Through reviewing latest research, this review summarized molecular markers and important signaling pathways for selective autophagy, and its significant role in cancers. Moreover, we conducted a comprehensive analysis of small-molecule compounds targeting selective autophagy for their potential application in anti-tumor therapy, elucidating the underlying mechanisms involved. This review aims to supply important scientific references and development directions for the biological mechanisms and drug discovery of anti-tumor targeting selective autophagy in the future.

Therapeutic potential of autophagy in immunity and inflammation: current and future perspectives

Autophagy is recognized as a lysosomal degradation pathway important for cellular and organismal homeostasis. Accumulating evidence has demonstrated that autophagy is a paradoxical mechanism that regulates homeostasis and prevents stress under physiological and pathological conditions. Nevertheless, how autophagy is implicated in immune responses remains unclear. It is well established that autophagy bridges innate and adaptive immunity, while autophagic dysfunction is closely related to infection, inflammation, neurodegeneration, and tumorigenesis. Therefore, autophagy has attracted great attention from fundamental and translational fields due to its crucial role in inflammation and immunity. Inflammation is involved in the development and progression of various human diseases, and as a result, autophagy might be a potential target to prevent and treat inflammatory diseases. Nevertheless, insufficient autophagy might cause cell death, perpetrate inflammation, and trigger hereditary unsteadiness. Hence, targeting autophagy is a promising disease prevention and treatment strategy. To accomplish this safely, we should thoroughly understand the basic aspects of how autophagy works. Herein, we systematically summarized the correlation between autophagy and inflammation and its implication for human diseases.

Membrane Curvature: The Inseparable Companion of Autophagy

Autophagy is a highly conserved recycling process of eukaryotic cells that degrades protein aggregates or damaged organelles with the participation of autophagy-related proteins. Membrane bending is a key step in autophagosome membrane formation and nucleation. A variety of autophagy-related proteins (ATGs) are needed to sense and generate membrane curvature, which then complete the membrane remodeling process. The Atg1 complex, Atg2-Atg18 complex, Vps34 complex, Atg12-Atg5 conjugation system, Atg8-phosphatidylethanolamine conjugation system, and transmembrane protein Atg9 promote the production of autophagosomal membranes directly or indirectly through their specific structures to alter membrane curvature. There are three common mechanisms to explain the change in membrane curvature. For example, the BAR domain of Bif-1 senses and tethers Atg9 vesicles to change the membrane curvature of the isolation membrane (IM), and the Atg9 vesicles are reported as a source of the IM in the autophagy process. The amphiphilic helix of Bif-1 inserts directly into the phospholipid bilayer, causing membrane asymmetry, and thus changing the membrane curvature of the IM. Atg2 forms a pathway for lipid transport from the endoplasmic reticulum to the IM, and this pathway also contributes to the formation of the IM. In this review, we introduce the phenomena and causes of membrane curvature changes in the process of macroautophagy, and the mechanisms of ATGs in membrane curvature and autophagosome membrane formation.