Targeting autophagy in disease: established and new strategies

circCUL3 drives malignant progression of cervical cancer by activating autophagy through sponge miR-223-3p upregulation of ATG7

Circular RNA (circRNA) has emerged as a pivotal regulatory factor in cancer biology, yet its exact role in cervical cancer remains incompletely understood. In this study, we investigated the functional role of circCUL3 in cervical cancer and explored its potential as a therapeutic target. Functional gain and loss experiments were conducted in Hela and Siha cell lines to elucidate the biological functions of circCUL3 in cervical cancer. The results revealed that circCUL3 overexpression significantly enhanced cell viability, migration, and invasion while suppressing apoptosis, while circCUL3 knockout displayed the opposite effects. Mechanistically, we identified hsa-miR-223-3p as a target of circCUL3, with its expression being negatively regulated by circCUL3. Furthermore, we discovered that circCUL3 could sequester miR-223-3p, leading to the upregulation of ATG7 expression, and this was linked to the regulation of autophagy in cervical cancer cells. In vivo validation using a xenograft mouse model further supported our in vitro findings. Notably, we found that chloroquine (CQ), an autophagy inhibitor, restored miR-223-3p expression and counteracted the oncogenic effect of circCUL3 overexpression. In conclusion, circCUL3 potentially contributes to the malignant progression of cervical cancer by acting as a sponge for miR-223-3p, resulting in the upregulation of ATG7 and the activation of autophagy.

Empagliflozin alleviates neuroinflammation by inhibiting astrocyte activation in the brain and regulating gut microbiota of high-fat diet mice

A high-fat diet can modify the composition of gut microbiota, resulting in dysbiosis. Changes in gut microbiota composition can lead to increased permeability of the gut barrier, allowing bacterial products like lipopolysaccharides (LPS) to enter circulation. This process can initiate systemic inflammation and contribute to neuroinflammation. Empagliflozin (EF), an SGLT2 inhibitor-type hypoglycemic drug, has been reported to treat neuroinflammation. However, there is a lack of evidence showing that EF regulates the gut microbiota axis to control neuroinflammation in HFD models. In this study, we explored whether EF could improve neuroinflammation caused by an HFD via regulation of the gut microbiota and the mechanism underlying this phenomenon. Our data revealed that EF alleviates pathological brain injury, reduces the reactive proliferation of astrocytes, and increases the expression of synaptophysin. In addition, the levels of inflammatory factors in hippocampal tissue were significantly decreased after EF intervention. Subsequently, the results of 16S rRNA gene sequencing showed that EF could change the microbial community structure of mice, indicating that the abundance of Lactococcus, Ligilactobacillus and other microbial populations decreased dramatically. Therefore, EF alleviates neuroinflammation by inhibiting gut microbiota-mediated astrocyte activation in the brains of high-fat diet-fed mice. Our study focused on the gut-brain axis, and broader research on neuroinflammation can provide a more holistic understanding of the mechanisms driving neurodegenerative diseases and inform the development of effective strategies to mitigate their impact on brain health. The results provide strong evidence supporting the larger clinical application of EF.

Mechanism of salidroside regulating autophagy based on network pharmacology and molecular docking

Salidroside is a natural product of phenols with a wide range of pharmacological functions, but whether it plays a role in regulating autophagy is unclear. We systematically investigated the regulatory effect and molecular mechanism of salidroside on autophagy through network pharmacology, which provided a theoretical basis for subsequent experimental research. First, the target genes of salidroside were obtained using the Chinese Medicine System Pharmacology Database and Analysis Platform, and the target genes were converted into standardized gene names using the Uniprot website. At the same time, autophagy-related genes were collected from GeneCards, and preliminary handling of data to obtain intersecting genes. Then, the String website was used to construct a protein-protein interaction network, and to perform the Gene Ontology functional annotation and Kyoto Encyclopedia of Genes and Genomes pathway analysis. To observe the specific molecular mechanism by which salidroside regulates autophagy, we constructed a drug component-target genes-autophagy network. Finally, we performed molecular docking to verify the possible binding conformation between salidroside and the candidate target. By searching the database and analyzing the data, we found that 113 target genes in salidroside interact with autophagy. Salidroside regulate autophagy in relation to a number of important oncogenes and signaling pathways. Molecular docking confirmed that salidroside has high affinity with mTOR, SIRT1, and AKT1. Through network pharmacology combined with molecular docking-validated research methods, we revealed the underlying mechanism of salidroside regulation of autophagy. This study not only provides new systematic insights into the underlying mechanism of salidroside in autophagy, but also provides new ideas for network approaches for autophagy-related research.

GPCR function in autophagy control: a systematic approach of chemical intervention

Autophagy facilitates the degradation of cellular content via the lysosome and is involved in cellular homeostasis and stress response pathways. As such, malfunction of autophagy is linked to a variety of diseases ranging from organ-specific illnesses like cardiomyopathy to systemic illnesses such as cancer or metabolic syndromes. Given the variety of autophagic functions within a cell and tissue, regulation of autophagy is complex and contains numerous positive and negative feedback loops. While our knowledge of mechanisms for cargo selectivity has significantly improved over the last decade, our understanding of signaling routes activating individual autophagy pathways remains rather sparse. In this resource study, we report on a well-characterized chemical library containing 77 GPCR-targeting ligands that was used to systematically analyze LC3B-based autophagy as well as ER-phagy flux upon compound treatment. Upon others, compounds TC-G 1004, BAY 60-6583, PSNCBAM-1, TC-G 1008, LPA2 Antagonist 1, ML154, JTC-801 and ML-290 targeting adenosine receptor A2a (ADORA2A), adenosine receptor A2b (ADORA2B), cannabinoid receptor 1 (CNR1), G-protein coupled receptor 39 (GPR39), lysophosphatidic acid receptor 2 (LPAR2), neuropeptide S receptor 1 (NPSR1), opioid related nociceptin receptor 1 (OPRL1), and relaxin receptor 1 (RXFP1), respectively, were hit compounds for general autophagy flux. From these compounds, only JTC-801 markly increased ER-phagy flux. In addition, the global impact of these selected hit compounds were analyzed by TMT-based mass spectrometry and demonstrated the differential impact of targeting GPCRs on autophagy-associated proteins. This chemical screening exercise indicates to a significant cross-talk between GPCR signaling and regulation of autophagy pathways.

High salt diet induces cognitive impairment and is linked to the activation of IGF1R/mTOR/p70S6K signaling

A high-salt diet (HSD) has been associated with various health issues, including hypertension and cardiovascular diseases. However, recent studies have revealed a potential link between high salt intake and cognitive impairment. This study aims to investigate the effects of high salt intake on autophagy, tau protein hyperphosphorylation, and synaptic function and their potential associations with cognitive impairment. To explore these mechanisms, 8-month-old male C57BL/6 mice were fed either a normal diet (0.4% NaCl) or an HSD (8% NaCl) for 3 months, and Neuro-2a cells were incubated with normal medium or NaCl medium (80 mM). Behavioral tests revealed learning and memory deficits in mice fed the HSD. We further discovered that the HSD decreased autophagy, as indicated by diminished levels of the autophagy-associated proteins Beclin-1 and LC3, along with an elevated p62 protein level. HSD feeding significantly decreased insulin-like growth factor-1 receptor (IGF1R) expression in the brain of C57BL/6 mice and activated mechanistic target of rapamycin (mTOR) signaling. In addition, the HSD reduced synaptophysin and postsynaptic density protein 95 (PSD95) expression in the hippocampus and caused synaptic loss in mice. We also found amyloid β accumulation and hyperphosphorylation of tau protein at different loci both in vivo and in vitro. Overall, this study highlights the clinical significance of understanding the impact of an HSD on cognitive function. By targeting the IGF1R/mTOR/p70S6K pathway or promoting autophagy, it may be possible to mitigate the negative effects of high salt intake on cognitive function.

Ethyl pyruvate alleviates pulmonary arterial hypertension via PI3K-Akt signaling

Pulmonary arterial hypertension (PAH) is a pathophysiological syndrome that is extremely difficult to manage, and there is currently no effective treatment. We want to elucidate the therapeutic effect of ethyl pyruvate (EP) on PAH and its possible mechanism. Pulmonary artery endothelial cells (PAECs) were cultured in conventional low-oxygen environments, and cellular proliferation was monitored after treatment with EP. Expression of p-PI3K/Akt, LC3-II, and Beclin-1 was detected by Western blot. After hyperkinetic PAH rabbits' models were treated with EP, hemodynamic data were collected. Right ventricular hypertrophy and pulmonary vascular remodeling were evaluated. Expression of p-PI3K/Akt, LC3-II, and Beclin-1 protein was also detected after using autophagy inhibitor and agonists. We found that EP could inhibit PAECs proliferation. After EP treatment, expression of p-PI3K/Akt was upregulated in vitro and in vivo. LC3-II and Beclin-1 were inhibited and their expression was lower after autophagy inhibitor was given, while after administration of autophagy agonists, their expression was higher than that in the EP alone group. Besides, EP attenuated PAH, and right ventricular hypertrophy and pulmonary vascular remodeling were also reversed. EP can reduce PAH and reverse vascular remodeling which is associated with inhibition of autophagy in PAECs based on PI3K-Akt signaling pathway. The results of this study can provide surgical opportunities for patients with severe PAH caused by congenital heart disease in clinical cardiovascular surgery.

Cross-talk between Vimentin and autophagy regulates blood-testis barrier disruption induced by cadmium

The blood-testis barrier (BTB) plays a vital role in mammalian spermatogenesis by separating the seminiferous epithelium into an adluminal and a basal compartment. Cadmium (Cd) is a toxic heavy metal that is widely present in the environment. We observed that Cd can induce BTB disruption, leading to apoptosis of testicular cells. However, the molecular mechanisms contributing to BTB injury induced by Cd have not yet been fully clarified. Vimentin (Vim) is an important desmosome-like junction protein that mediates robust adhesion in the BTB. In this study, we investigated how Vim responds to Cd. We found that Cd treatment led to a significant decrease in Vim expression, accompanied by a marked increase in LC3-II expression and a higer number of autophagosomes. Interestingly, we also observed that Cd-induced autophagy was associated with decreased Vim activity and enhanced apoptosis of testicular cells. To further investigate the role of autophagy in Vim regulation under Cd exposure, we treated cells with an autophagy inhibitor called 3-MA. We found that 3-MA treatment enhanced Vim expression and improved the disruption of the BTB under Cd exposure. Additionally, the inhibition of Vim confirmed the role of autophagy in modulating Vim expression. These results reveal a previously unknown regulatory mechanism of Cd involving the interplay between a heavy metal and a protein.

Polystyrene microplastics mediate cell cycle arrest, apoptosis, and autophagy in the G2/M phase through ROS in grass carp kidney cells

Microplastics (MPs) have attracted widespread worldwide attention as a new pollutant. However, the role of reactive oxygen species (ROS) and cell cycle in nephrotoxicity induced by different concentrations of polystyrene microplastics (PS-MPs) is unknown. This study used grass carp kidney cells (CIK) treated with different concentrations of PS-MPs (0, 0.012, 0.0625, and 0.5 mg L-1 ) as subjects. With the increase of PS-MPs concentration, the levels of ROS and malonaldehyde increased, while the level of total antioxidant capacity, superoxide Dismutase (SOD), and glutathione (GSH) activity decreased. The expression of BUB1 mitotic checkpoint serine/threonine kinase (BUB1), cyclin-dependent kinase (CDK1), CDK2, CyclinB1, cell division cycle 20 homolog (CDC20), and B-cell lymphoma-2, sequestosome 1 decreased significantly. Nevertheless, the expression of Caspase 3, Cleave-Caspase 3, cytochrome c (Cytc), BCL2-associated X, apoptosis regulator, poly ADP-ribose polymerase (PARP), Cleave-PARP, Caspase 9, autophagy immunoblot kit (LC3), and Beclin1 increased. Our research shows that PS-MPs can trigger oxidative stress and induce cell cycle arrest, apoptosis, and autophagy in CIK cells by regulating ROS. This work provides a theoretical basis for cellular biology and toxicology mechanisms and new insights into the potential risks to animals from MPs exposure in the environment.

Andrographolide acts with dexamethasone to inhibit the growth of acute lymphoblastic leukemia CEM‑C1 cells via the regulation of the autophagy‑dependent PI3K/AKT/mTOR signaling pathway

Acute lymphoblastic leukemia (ALL) is one of the most common malignant tumor types of the circulatory system. Dexamethasone (DEX) acts on the glucocorticoid (GC) receptor (GR) and is a first-line chemotherapy drug for ALL. However, long-term or high-dose applications of the drug can not only cause adverse reactions, such as osteoporosis and high blood pressure, but can also cause downregulation of GR and lead to drug resistance. In the present study, reverse transcription-quantitative PCR, western blotting and LysoTracker Red staining were used to observe the effects of DEX and andrographolide (AND; a botanical with antitumorigenic properties) combined treatment. It was found that AND enhanced the sensitivity of CEM-C1 cells, a GC-resistant cell line, to DEX, and synergistically upregulated GR both at the transcriptional and post-transcriptional level with DEX. The combination of AND with DEX synergistically alkalized lysosomal lumen and downregulated the expression of autophagy-related genes Beclin1 and microtubule-associated 1 protein light chain 3 (LC3), thereby inhibiting autophagy. Knocking down LC3 expression enhanced GR expression, suggesting that GR was regulated by autophagy. Furthermore, compared with the monotherapy group (AND or DEX in isolation), AND interacted with DEX to activate the autophagy-dependent PI3K/AKT/mTOR signaling pathway by enhancing the phosphorylation of PI3K, AKT and mTOR, thereby decreasing GR degradation and increasing the sensitivity of cells to GCs. In conclusion, the present study demonstrated that AND exhibited a synergistic anti-ALL effect with DEX via upregulation of GR, which was orchestrated by the autophagy-related PI3K/AKT/mTOR signaling pathway. The results of the present study therefore provided novel research avenues and strategies for the treatment of ALL.

Emerging role and mechanism of HACE1 in the pathogenesis of neurodegenerative diseases: A promising target

HACE1 is a member of the HECT domain-containing E3 ligases with 909 amino acid residues, containing N-terminal ankyrin-repeats (ANK) and C-terminal HECT domain. Previously, it was shown that HACE1 is inactive in human tumors and plays a crucial role in the initiation, progression, and invasion of malignant tumors. Recent studies indicated that HACE1 might be closely involved in neurodegenerative diseases such as Alzheimer's disease, Parkinson's disease, and Huntington's disease. HACE1 interacts with its substrates, including Ras-related C3 botulinum toxin substrate 1 (Rac1), nuclear factor erythroid 2-related factor 2 (Nrf2), tumor necrosis factor receptor (TNFR), and optineurin (OPTN), through which participates in several pathophysiological processes, such as oxidative stress, autophagy and inflammation. Therefore, in this review, we elaborately describe the essential substrates of HACE1 and illuminate the pathophysiological processes by which HACE1 is involved in neurodegenerative diseases. We provide a new molecular target for neurodegenerative diseases.

AAA237, an SKP2 inhibitor, suppresses glioblastoma by inducing BNIP3-dependent autophagy through the mTOR pathway

BACKGROUND

Glioblastoma (GBM) is the most common brain tumor with the worst prognosis. Temozolomide is the only first-line drug for GBM. Unfortunately, the resistance issue is a classic problem. Therefore, it is essential to develop new drugs to treat GBM. As an oncogene, Skp2 is involved in the pathogenesis of various cancers including GBM. In this study, we investigated the anticancer effect of AAA237 on human glioblastoma cells and its underlying mechanism.

METHODS

CCK-8 assay was conducted to evaluate IC50 values of AAA237 at 48, and 72 h, respectively. The Cellular Thermal Shift Assay (CETSA) was employed to ascertain the status of Skp2 as an intrinsic target of AAA237 inside the cellular milieu. The EdU-DNA synthesis test, Soft-Agar assay and Matrigel assay were performed to check the suppressive effects of AAA237 on cell growth. To identify the migration and invasion ability of GBM cells, transwell assay was conducted. RT-qPCR and Western Blot were employed to verify the level of BNIP3. The mRFP-GFP-LC3 indicator system was utilized to assess alterations in autophagy flux and investigate the impact of AAA237 on the dynamic fusion process between autophagosomes and lysosomes. To investigate the effect of compound AAA237 on tumor growth in vivo, LN229 cells were injected into the brains of mice in an orthotopic model.

RESULTS

AAA237 could inhibit the growth of GBM cells in vitro. AAA237 could bind to Skp2 and inhibit Skp2 expression and the degradation of p21 and p27. In a dose-dependent manner, AAA237 demonstrated the ability to inhibit colony formation, migration, and invasion of GBM cells. AAA237 treatment could upregulate BNIP3 as the hub gene and therefore induce BNIP3-dependent autophagy through the mTOR pathway whereas 3-MA can somewhat reverse this process. In vivo, the administration of AAA237 effectively suppressed the development of glioma tumors with no side effects.

CONCLUSION

Compound AAA237, a novel Skp2 inhibitor, inhibited colony formation, migration and invasion of GBM cells in a dose-dependent manner and time-dependent manner through upregulating BNIP3 as the hub gene and induced BNIP3-dependent autophagy through the mTOR pathway therefore it might be a viable therapeutic drug for the management of GBM.

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.

Neutrophil extracellular traps in central nervous system (CNS) diseases

Excessive induction of inflammatory and immune responses is widely considered as one of vital factors contributing to the pathogenesis and progression of central nervous system (CNS) diseases. Neutrophils are well-studied members of inflammatory and immune cell family, contributing to the innate and adaptive immunity. Neutrophil-released neutrophil extracellular traps (NETs) play an important role in the regulation of various kinds of diseases, including CNS diseases. In this review, current knowledge on the biological features of NETs will be introduced. In addition, the role of NETs in several popular and well-studied CNS diseases including cerebral stroke, Alzheimer's disease, multiple sclerosis, amyotrophic lateral sclerosis (ALS), and neurological cancers will be described and discussed through the reviewing of previous related studies.

Lifestyle strategies to promote proteostasis and reduce the risk of Alzheimer's disease and other proteinopathies

Unhealthy lifestyle choices, poor diet, and aging can have negative influences on cognition, gradually increasing the risk for mild cognitive impairment (MCI) and the continuum comprising early dementia. Aging is the greatest risk factor for age-related dementias such as Alzheimer's disease, and the aging process is known to be influenced by life events that can positively or negatively affect age-related diseases. Remarkably, life experiences that make the brain vulnerable to dementia, such as seizure episodes, neurotoxin exposures, metabolic disorders, and trauma-inducing events (e.g. traumatic injuries or mild neurotrauma from a fall or blast exposure), have been associated with negative effects on proteostasis and synaptic integrity. Functional compromise of the autophagy-lysosomal pathway, a major contributor to proteostasis, has been implicated in Alzheimer's disease, Parkinson's disease, obesity-related pathology, Huntington's disease, as well as in synaptic degeneration which is the best correlate of cognitive decline. Correspondingly, pharmacological and non-pharmacological strategies that positively modulate lysosomal proteases are recognized as synaptoprotective through degradative clearance of pathogenic proteins. Here, we discuss life-associated vulnerabilities that influence key hallmarks of brain aging and the increased burden of age-related dementias. Additionally, we discuss exercise and diet among the lifestyle strategies that regulate proteostasis as well as synaptic integrity, leading to evident prevention of cognitive deficits during brain aging in pre-clinical models.

VAMP8 suppresses the metastasis via DDX5/β-catenin signal pathway in osteosarcoma

Osteosarcoma is a highly metastatic malignant bone tumor, necessitating the development of new treatments to target its metastasis. Recent studies have revealed the significance of VAMP8 in regulating various signaling pathways in various types of cancer. However, the specific functional role of VAMP8 in osteosarcoma progression remains unclear. In this study, we observed a significant downregulation of VAMP8 in osteosarcoma cells and tissues. Low levels of VAMP8 in osteosarcoma tissues were associated with patients' poor prognosis. VAMP8 inhibited the migration and invasion capability of osteosarcoma cells. Mechanically, we identified DDX5 as a novel interacting partner of VAMP8, and the conjunction of VAMP8 and DDX5 promoted the degradation of DDX5 via the ubiquitin-proteasome system. Moreover, reduced levels of DDX5 led to the downregulation of β-catenin, thereby suppressing the epithelial-mesenchymal transition (EMT). Additionally, VAMP8 promoted autophagy flux, which may contribute to the suppression of osteosarcoma metastasis. In conclusion, our study anticipated that VAMP8 inhibits osteosarcoma metastasis by promoting the proteasomal degradation of DDX5, consequently inhibiting WNT/β-catenin signaling and EMT. Dysregulation of autophagy by VAMP8 is also implicated as a potential mechanism. These findings provide new insights into the biological nature driving osteosarcoma metastasis and highlight the modulation of VAMP8 as a potential therapeutic strategy for targeting osteosarcoma metastasis.

A20 ameliorates Aspergillus fumigatus keratitis by promoting autophagy and inhibiting NF-κB signaling

Fungal keratitis (FK) is a serious, potentially sight-threatening corneal infection, which is associated with poor prognosis. A20, also called TNFAIP3, plays significant roles in the negative regulation of inflammation and immunity. However, the function of A20 in Aspergillus fumigatus (A. fumigatus) keratitis remains obscure. Herein, we found that the level of A20 is increased in human corneal epithelial cells (HCECs) and in mouse corneas with A. fumigatus infection, and that nuclear factor-κB (NF-κB) signaling is required for A20 upregulation. A20 overexpression inhibits A. fumigatus-mediated inflammatory responses, while A20 knockdown results in opposite effect. Mechanically, we showed that A20 inhibits NF-κB signaling and activates autophagy in infected HCECs. We also showed that inhibition of NF-κB signaling reverses the increased inflammatory responses in infected HCECs with A20 knockdown. Furthermore, autophagy blockage impedes the anti-inflammatory effect of A20 in A. fumigatus infected HCECs. Moreover, A20 ameliorates the corneal damage and inflammation in A. fumigatus infected mouse corneas. In conclusion, this study reveals that A20 alleviates A. fumigatus keratitis by activating autophagy and inhibiting NF-κB signaling. This suggests that exogenous use of A20 protein may be a potentially promising therapeutic strategy for FK treatment.

A Stable Micellar Formulation of RAD001 for Intracerebroventricular Delivery and the Treatment of Alzheimer's Disease and Other Neurological Disorders

A large body of evidence, replicated in many mouse models of Alzheimer's disease (AD), supports the therapeutic efficacy of the oral mammalian target of rapamycin inhibitors (mTOR-Is). Our preliminary data show that intracerebroventricular (ICV) administration of everolimus (RAD001) soon after clinical onset greatly diminished cognitive impairment and the intracellular beta amyloid and neurofibrillary tangle load. However, RAD001 shows >90% degradation after 7 days in solution at body temperature, thus hampering the development of proper therapeutic regimens for patients. To overcome such a drawback, we developed a stable, liquid formulation of mTOR-Is by loading RAD001 into distearoylphosphatidylethanolamine-polyethylene glycol 2000 (DSPE-PEG2000) micelles using the thin layer evaporation method. The formulation showed efficient encapsulation of RAD001 and a homogeneous colloidal size and stabilised RAD001, with over 95% of activity preserved after 14 days at 37 °C with a total decay only occurring after 98 days. RAD001-loaded DSPE-PEG2000 micelles were unchanged when stored at 4 and 25 °C over the time period investigated. The obtained formulation may represent a suitable platform for expedited clinical translation and effective therapeutic regimens in AD and other neurological diseases.

Glucose dysregulation promotes oncogenesis in human bladder cancer by regulating autophagy and YAP1/TAZ expression

Glucose dysregulation is strongly correlated with cancer development, and cancer is prevalent in patients with Type 2 diabetes (T2D). We aimed to elucidate the mechanism underlying autophagy in response to glucose dysregulation in human bladder cancer (BC). 220 BC patients were included in this retrospective study. The expression of YAP1, TAZ and AMPK, EMT-associated markers, and autophagy marker proteins was analysed by immunohistochemistry, western blotting, and quantitative real-time PCR (qPCR). Further, T24 and UMUC-3 BC cells were cultured in media with different glucose concentrations, and the expression of YAP1, TAZ, AMPK and EMT-associated markers, and autophagy marker proteins was analysed by western blotting and qPCR. Autophagy was observed by immunofluorescence and electron microscopy. BC cell viability was tested using MTT assays. A xenograft nude mouse model of diabetes was used to evaluate tumour growth, metastasis and survival. A poorer pathologic grade and tumour-node-metastasis stage were observed in patients with BC with comorbid T2D than in others with BC. YAP1 and TAZ were upregulated in BC samples from patients with T2D. Mechanistically, high glucose (HG) promoted BC progression both in vitro and in vivo and inhibited autophagy. Specifically, various autophagy marker proteins and AMPK were negatively regulated under HG conditions and correlated with YAP1 and TAZ expression. These results demonstrate that HG inhibits autophagy and promotes cancer development in BC. YAP1/TAZ/AMPK signalling plays a crucial role in regulating glucose dysregulation during autophagy. Targeting these effectors exhibits therapeutic significance and can serve as prognostic markers in BC patients with T2D.

Melatonin-mediated mitophagy protects against long-term impairments after repeated neonatal sevoflurane exposures

BACKGROUND

Melatonin is known to have protective effects in aging, neurodegenerative disorders and mitochondria-related diseases, while there is a poor understanding of the effects of melatonin treatment on mitophagy in neonatal cognitive dysfunction after repeated sevoflurane exposures. This study explores the protective effects of melatonin on mitophagy and cognition in developing rats exposed to sevoflurane.

METHODS

Postnatal day six (P6) neonatal rats were exposed to 3 % sevoflurane for 2 h daily from P6 to P8. In the intervention groups, rats received 3-Methyladenine (3-MA) intracerebroventricularly from P6 to P8 and melatonin intraperitoneally from P6 to P8 following water drinking once daily from P21 to P41, respectively. Behavioral tests, including open field (OF), novel object recognition (NOR), and fear conditioning (FC) tests, were performed to assess cognitive function during young adulthood. In another experiment, rat brains were harvested for biochemical, histopathological, and electron microscopy studies.

RESULTS

Rats exposed to sevoflurane showed disordered mitophagy and mitochondrial dysfunction as revealed by increased mitophagy marker proteins (microtubule-associated protein 1 light chain 3 (LC3) II/I, and parkin), decreased autophagy marker protein (sequestosome 1 (P62/SQSTM1)), electron transport chain (ETC) proteins and ATP levels. Immunofluorescent staining of LC3 was co-localized mostly with a neuronal marker and microglial marker but was not co-localized with a marker for astrocytes in rats exposed to sevoflurane. These rats had poorer performance in the NOR and FC tests than control rats during young adulthood. Melatonin treatment reversed the abnormal expression of mitophagy proteins, mitochondrial energy metabolism, the activity of microglia, and impaired cognition. These ameliorations were blocked by an autophagy inhibitor, 3-MA, except for the activation of microglia.

CONCLUSION

We have demonstrated that melatonin inhibits microglial activation by enhancing mitophagy and finally significantly reduces sevoflurane-induced deficits in cognition in neonatal rats. These results suggest that melatonin might be beneficial if considered when the anesthesia must be administered at a very young age.

Nanomedicine-mediated regulated cell death in cancer immunotherapy

Immunotherapy has attracted widespread attention in cancer treatment and has achieved considerable success in the clinical treatment of some tumors, but it has a low response rate in most tumors. To achieve sufficient activation of the immune response, significant efforts using nanotechnology have been made to enhance cancer immune response. In recent years, the induction of various regulated cell death (RCD) has emerged as a potential antitumor immuno-strategy, including processes related to apoptosis, autophagy, necroptosis, pyroptosis, ferroptosis, and cuproptosis. In particular, damage-associated molecular patterns (DAMPs) released from the damaged membrane of dying cells act as in situ adjuvants to trigger antigen-specific immune responses by the exposure of an increased antigenicity. Thus, RCD-based immunotherapy offers a new approach for enhancing cancer treatment efficacy. Furthermore, incorporation with multimodal auxiliary therapies in cell death-based immunotherapy can trigger stronger immune responses, resulting in more efficient therapeutic outcome. This review discusses different RCD modalities and summarizes recent nanotechnology-mediated RCDs in cancer immunotherapy.

Pharmacogenetic Association between Allelic Variants of the Autophagy-Related Genes and Anti-Vascular Endothelial Growth Factor Treatment Response in Neovascular Age-Related Macular Degeneration

BACKGROUND

Age-related macular degeneration (AMD) is the leading cause of late-onset blindness in elderly. The occurrence and development of AMD is a multifactorial complex process where autophagy plays an important role. The first-line drugs for neovascular AMD (nAMD) are inhibitors of VEGF, with up to 30% of patients having an incomplete response to treatment. Genetic factors may influence the response to anti-VEGF therapy and explain treatment outcome variability. We aimed to estimate the role of polymorphic markers of the MTOR (rs1064261, rs1057079, rs11121704, rs2295080), SQSTM1 (rs10277), ULK1 (rs11246867, rs3088051), MAP1LC3A (rs73105013) and ATG5 (rs573775) genes in the development of nAMD and the efficacy of anti-VEGF therapy response.

METHODS

Genotyping by allele-specific PCR was performed in 317 controls and 315 nAMD patients in the Russian population. Of them, 196 treatment-naive nAMD patients underwent three monthly intravitreal injections (IVIs) of aflibercept. Genotypic frequencies were compared with OCT markers of therapy effectiveness and best-corrected visual acuity (BCVA) measures. The main outcomes were the BCVA gain and decrease in central retinal thickness (CRT).

RESULTS

MTOR-rs1057079-C, MTOR-rs11121704-C and MTOR-rs2295080-G alleles were associated with an increased risk of nAMD. The BCVA was increased in 117 (59.7%) patients by 10 [5-20] letters, did not changed in 59 (30.1%), and was decreased in 20 (10.2%) patients. ULK1-rs3088051 was associated with BCVA change. Among patients with the TT and CT genotypes for ULK1-rs3088051, an improvement in visual acuity was noted in 67.6% and 53.8% of cases, while in patients with the CC genotype, an increase in BCVA was recorded in 37.5% of cases (p = 0.01). The decrease in CRT was associated with SQSTM1-rs10277 (p = 0.001): it was significantly higher in TT (93 [58-122] mkm) and CT (66 [30-105] mkm) carriers compared to the CC genotype (47 [24-68] mkm). Other SNPs did not show significant associations with the outcome of anti-VEGF treatment.

CONCLUSIONS

MTOR gene polymorphisms are moderately associated with the risk of nAMD. SQSTM1-rs10277 and ULK1-rs3088051 may influence short-term response to intravitreal anti-VEGF treatment. The results suggest that autophagy could be a target for future drugs to overcome resistance to anti-VEGF therapy.

Microcolin H, a novel autophagy inducer, exerts potent antitumour activity by targeting PITPα/β

The identification of effective drug targets and the development of bioactive molecules are areas of high need in cancer therapy. The phosphatidylinositol transfer protein alpha/beta isoform (PITPα/β) has been reported to play an essential role in integrating phosphoinositide trafficking and lipid metabolism in diverse cellular processes but remains unexplored as a potential target for cancer treatment. Herein, data analysis of clinical cancer samples revealed that PITPα/β expression is closely correlated with the poor prognosis. Target identification by chemical proteomic methods revealed that microcolin H, a naturally occurring marine lipopeptide, directly binds PITPα/β and displays antiproliferative activity on different types of tumour cell lines. Furthermore, we identified that microcolin H treatment increased the conversion of LC3I to LC3II, accompanied by a reduction of the level of p62 in cancer cells, leading to autophagic cell death. Moreover, microcolin H showed preeminent antitumour efficacy in nude mouse subcutaneous tumour models with low toxicity. Our discoveries revealed that by targeting PITPα/β, microcolin H induced autophagic cell death in tumours with efficient anti-proliferating activity, which sheds light on PITPα/β as a promising therapeutic target for cancer treatment.

Activation of ULK1 to trigger FUNDC1-mediated mitophagy in heart failure: Effect of Ginsenoside Rg3 intervention

BACKGROUND

Although the development of therapies for heart failure (HF) continues apace, clinical outcomes are often far from ideal. Unc51-like-kinase 1 (ULK1)-mediated mitophagy prevents pathological cardiac remodeling and heart failure (HF). Molecularly ULK1-targeted agent to enhance mitophagy is scanty.

HYPOTHESIS/PURPOSE

This study aimed to investigate whether Ginsenoside Rg3 (Rg3) can activate ULK1 to trigger FUNDC1-mediated mitophagy for protecting heart failure.

METHODS

Molecular docking and surface plasmon resonance were used to detect the ULK1 binding behavior of Rg3. Established HF model in rats and transcriptome sequencing were used to evaluate the therapeutic effect and regulatory mechanism of Rg3. Loss-of-function approaches in vivo and in vitro were performed to determine the role of ULK1 in Rg3-elicited myocardial protection against HF. FUNDC1 recombinant plasmid of site mutation was applied to elucidate more in-depth mechanisms.

RESULTS

Structurally, a good binding mode was unveiled between ULK1 and Rg3. In vivo, Rg3 improved cardiac dysfunction, adverse remodeling, and mitochondrial damage in HF rats. Furthermore, Rg3 promoted Ulk1-triggered mitophagy both in vivo and in vitro, manifested by the impetus of downstream Fundc1-Lc3 interaction. Of note, the protective effects conferred by Rg3 against mitophagy defects, pathological remodeling, and cardiac dysfunction were compromised by Ulk1 gene silencing both in vivo and in vitro. Mechanistically, Rg3 activated mitophagy by inducing ULK1-mediated phosphorylation of FUNDC1 at the Ser17 site, not the Ser13 site.

CONCLUSION

Together these observations demonstrated that Rg3 acts as a ULK1 activator for the precise treatment of HF, which binds to ULK1 to activate FUNDC1-mediated mitophagy.

Combating drug resistance in hepatocellular carcinoma: No awareness today, no action tomorrow

Hepatocellular carcinoma (HCC), the sixth most common cancer worldwide, is associated with a high degree of malignancy and poor prognosis. Patients with early HCC may benefit from surgical resection to remove tumor tissue and a margin of healthy tissue surrounding it. Unfortunately, most patients with HCC are diagnosed at an advanced or distant stage, at which point resection is not feasible. Systemic therapy is now routinely prescribed to patients with advanced HCC; however, drug resistance has become a major obstacle to the treatment of HCC and exploring purported mechanisms promoting drug resistance remains a challenge. Here, we focus on the determinants of drug resistance from the perspective of non-coding RNAs (ncRNAs), liver cancer stem cells (LCSCs), autophagy, epithelial-mesenchymal transition (EMT), exosomes, ferroptosis, and the tumor microenvironment (TME), with the aim to provide new insights into HCC treatment.

Agaricus blazei Murrill Polysaccharide Attenuates Periodontitis via H2 S/NRF2 Axis-Boosted Appropriate Level of Autophagy in PDLCs

SCOPE

Periodontitis is one of the most prevalent chronic inflammatory diseases with impaired autophagy. Agaricus blazei Murrill polysaccharide (ABMP) shows beneficial effects in various inflammatory diseases. However, whether ABMP is involved in autophagy regulation and periodontitis attenuation remains to be elucidated.

METHODS AND RESULTS

This study firstly shows the dynamic changes in inflammatory and autophagy levels in silk ligature periodontitis model. Then the positive regulation effect of autophagy on inflammation and its vital role in ABMP inhibiting PDLCs inflammatory response are testified in LPS-treated PDLCs. Secondly, the Micro-CT, quantitative RT-PCR, Western Blot, TRAP, and immunofluorescence staining analysis are performed to assess the effects of ABMP on periodontitis and autophagy. The data show the augmented autophagy and alleviated gingival recession, inflammatory cell infiltration, alveolar bone resorption, and reduced osteoclasts in periodontitis by ABMP treatment. Further experiments using chemical inhibitors demonstrate the vital role of H2 S/NRF2 axis in ABMP-induced appropriate level of autophagy augmentation against periodontitis.

CONCLUSIONS

Collectively, the findings not only reveal the unrecognized capacity and mechanism of ABMP as an effective and potential dietary intake against periodontitis, but also suggest the possibility for ABMP to be used in the treatment of other autophagy-related diseases.

TACkling Cancer by Targeting Selective Protein Degradation

Targeted protein degradation has emerged as an alternative therapy against cancer, offering several advantages over traditional inhibitors. The new degrader drugs provide different therapeutic strategies: they could cross the phospholipid bilayer membrane by the addition of specific moieties to extracellular proteins. On the other hand, they could efficiently improve the degradation process by the generation of a ternary complex structure of an E3 ligase. Herein, we review the current trends in the use of TAC-based technologies (TACnologies), such as PROteolysis TArgeting Chimeras (PROTAC), PHOtochemically TArgeting Chimeras (PHOTAC), CLIck-formed Proteolysis TArgeting Chimeras (CLIPTAC), AUtophagy TArgeting Chimeras (AUTAC), AuTophagosome TEthering Compounds (ATTEC), LYsosome-TArgeting Chimeras (LYTAC), and DeUBiquitinase TArgeting Chimeras (DUBTAC), in experimental development and their progress towards clinical applications.

hucMSCs Treatment Ameliorated Pulmonary Fibrosis via Downregulating the circFOXP1-HuR-EZH2/STAT1/FOXK1 Autophagic Axis

This study was performed to determine the effect of human umbilical cord mesenchymal stem cells (hucMSCs) treatment on pulmonary fibrosis and investigate the circFOXP1-mediated autophagic mechanism of hucMSCs treatment. Pulmonary fibrosis models were established by spraying bleomycin in mice and TGF-β1 treatment of MRC-5 cells. Results showed that hucMSCs were retained in lung and hucMSCs treatment alleviated pulmonary fibrosis. Morphological staining indicated that hucMSCs-treated mice had thinner alveolar walls, effectively improved alveolar structure, significantly reduced alveolar inflammation, and decreased collagen deposition than control mice. Fibrotic proteins, including vimentin, α-SMA, collagens I and III, and the differentiation-related protein S100 calcium-binding protein A4 was reduced considerably in the hucMSCs-treated group. The mechanistic study revealed that the inhibition of hucMSCs treatment on pulmonary fibrogenesis depended on downregulating circFOXP1, in which hucMSCs treatment promoted circFOXP1-mediated autophagy process via blocking the nuclear human antigen R (HuR) translocation and promoting the HuR degradation, leading to a marked decrease in autophagy negative regulators EZH2, STAT1, and FOXK1. In conclusion, hucMSCs treatment significantly improved pulmonary fibrosis by downregulating the circFOXP1-HuR-EZH2/STAT1/FOXK1 autophagic axis. hucMSCs can act as an effective treatment for pulmonary fibrosis.

Autophagy and Inflammation: Regulatory Roles in Viral Infections

Autophagy is a highly conserved intracellular degradation pathway in eukaryotic organisms, playing an adaptive role in various pathophysiological processes throughout evolution. Inflammation is the immune system's response to external stimuli and tissue damage. However, persistent inflammatory reactions can lead to a range of inflammatory diseases and cancers. The interaction between autophagy and inflammation is particularly evident during viral infections. As a crucial regulator of inflammation, autophagy can either promote or inhibit the occurrence of inflammatory responses. In turn, inflammation can establish negative feedback loops by modulating autophagy to suppress excessive inflammatory reactions. This interaction is pivotal in the pathogenesis of viral diseases. Therefore, elucidating the regulatory roles of autophagy and inflammation in viral infections will significantly enhance our understanding of the mechanisms underlying related diseases. Furthermore, it will provide new insights and theoretical foundations for disease prevention, treatment, and drug development.

Identification of Hub Genes and Typing of Tuberculosis Infections Based on Autophagy-Related Genes

Tuberculosis (TB) caused by Mycobacterium tuberculosis is one of the leading causes of morbidity and death in humans worldwide. Some autophagy genes associated with TB and some miRNAs regulating TB have been found, but the identification of autophagy-related genes in M. tuberculosis remains to be explored. Forty-seven autophagy-related genes differentially expressed in TB were identified in this study by analysis of TB-related datasets in the Gene Expression Omnibus (GEO) and autophagy-related genes in the Human Autophagy Database. The potential crucial genes affecting TB were found through the protein-protein interaction (PPI) network, and the possible pathways affected by these genes were verified. Analysis of the PPI network of miRNAs associated with M. tuberculosis infection and their target genes revealed that hsa-let-7, hsa-mir-155, hsa-mir-206, hsa-mir-26a, hsa-mir-30a, and hsa-mir-32 may regulate the expression of multiple autophagy-related genes (MAPK8, UVRAG, UKL2, and GABARAPL1) alone or in combination. Subsequently, Cytoscape was utilized to screen the differentially expressed genes related to autophagy. The hub genes (GABARAPL1 and ULK2) affecting TB were identified. Combined with Gene Set Enrichment Analysis (GSEA), the signaling pathways affected by the hub genes were verified. Finally, we divided TB patients into two subgroups based on autophagy-related genes, and the immune microenvironment of patients in different subgroups was significantly different. Our study found two autophagy-related hub genes that could affect TB and divide TB samples into two subgroups. This finding is of great significance for TB treatment and provides new ideas for exploring the pathogenesis of M. tuberculosis.

Autophagy inhibitors for cancer therapy: Small molecules and nanomedicines

Autophagy is a conserved process in which the cytosolic materials are degraded and eventually recycled for cellular metabolism to maintain homeostasis. The dichotomous role of autophagy in pathogenesis is complicated. Accumulating reports have suggested that cytoprotective autophagy is responsible for tumor growth and progression. Autophagy inhibitors, such as chloroquine (CQ) and hydroxychloroquine (HCQ), are promising for treating malignancies or overcoming drug resistance in chemotherapy. With the rapid development of nanotechnology, nanomaterials also show autophagy-inhibitory effects or are reported as the carriers delivering autophagy inhibitors. In this review, we summarize the small-molecule compounds and nanomaterials inhibiting autophagic flux as well as the mechanisms involved. The nanocarrier-based drug delivery systems for autophagy inhibitors and their distinct advantages are also described. The progress of autophagy inhibitors for clinical applications is finally introduced, and their future perspectives are discussed.

Autophagy and podocytopathy

Autophagy is a complex process of lysosomal-dependent degradation of unwanted cellular material. In response to endogenous or exogenous stimuli, autophagy is induced and regulated by two kinases: the AMP activated kinase and the mammalian target of rapamycin (mTOR). Cells activated by Unc-51-like kinase 1 form a double membrane complex that sequesters the cargo (phagophore) and elongates producing spherical vesicles (autophagosomes). These reach and fuse with lysosomes, which degrade the cargo (autolysosomes). The resulting macromolecules are released back and recycled in the cytosol for reuse. In the podocyte, autophagy is a homeostatic mechanism that contributes to the formation and preservation of the morphological and functional integrity of actin cytoskeleton. Podocytes, fenestrated endothelial cells and glomerular basement membrane compose the glomerular filtration barrier. Podocyte damage may cause dysfunction of the glomerular barrier, proteinuria and glomerulosclerosis in different glomerular diseases and particularly in so-called podocytopathies, namely minimal change disease and focal segmental glomerulosclerosis. Several drugs and molecules may activate autophagic function in murine models. Among them, aldosterone inhibitors, mineralocorticoid inhibitors and vitamin D3 were proven to protect podocyte from injury and reduce proteinuria in clinical studies. However, no clinical trial with autophagy regulators in podocytopathies has been conducted. Caution is needed with other autophagy activators, such as mTOR inhibitors and metformin, because of potential adverse events.

Vanadium complex as a potential modulator of the autophagic mechanism through proteins PI3K and ULK1: development, validation and biological implications of a specific force field for [VO(bpy)2Cl]

The modulation of autophagy has been presented as a very useful strategy in anticancer treatments. In this sense, the vanadium complex (VC) bis(2,2'-bipyridine)chlorooxovanadium(IV), [VO(bpy)2Cl], is known for its ability to induce autophagy in triple-negative breast cancer cells (TNBC). An excellent resource to investigate the role of VC in the induction of autophagy is to make use of Molecular Dynamics (MD) simulations. However, until now, the scarcity of force field parameters for the VC prevented a reliable analysis. The autophagy signaling pathway starts with the PI3K protein and ends with ULK1. Therefore, in the first stage of this work, we developed a new AMBER force field for the VC (VCFF) from a quantum structure, obtained by DFT calculations. In the second stage, the VCFF was validated through structural analyses. From this, it was possible to investigate, through docking and MD (200 ns), the performance of the PI3K-VC and ULK1-VC systems (third stage). The analyses of this last stage involved RMSD, hydrogen bonds, RMSF and two pathways for the modulation of autophagy. In general, this work fills in the absence of force field parameters (FF) for VC by proposing an efficient and new FF, in addition to investigating, at the molecular level, how VC is able to induce autophagy in TNBC cells. This study encourages new parameterizations of metallic complexes and contributes to the understanding of the duality of autophagic processes.Communicated by Ramaswamy H. Sarma.

Autophagy and autophagy-related pathways in cancer

Maintenance of protein homeostasis and organelle integrity and function is critical for cellular homeostasis and cell viability. Autophagy is the principal mechanism that mediates the delivery of various cellular cargoes to lysosomes for degradation and recycling. A myriad of studies demonstrate important protective roles for autophagy against disease. However, in cancer, seemingly opposing roles of autophagy are observed in the prevention of early tumour development versus the maintenance and metabolic adaptation of established and metastasizing tumours. Recent studies have addressed not only the tumour cell intrinsic functions of autophagy, but also the roles of autophagy in the tumour microenvironment and associated immune cells. In addition, various autophagy-related pathways have been described, which are distinct from classical autophagy, that utilize parts of the autophagic machinery and can potentially contribute to malignant disease. Growing evidence on how autophagy and related processes affect cancer development and progression has helped guide efforts to design anticancer treatments based on inhibition or promotion of autophagy. In this Review, we discuss and dissect these different functions of autophagy and autophagy-related processes during tumour development, maintenance and progression. We outline recent findings regarding the role of these processes in both the tumour cells and the tumour microenvironment and describe advances in therapy aimed at autophagy processes in cancer.

A new perspective on the autophagic and non-autophagic functions of the GABARAP protein family: a potential therapeutic target for human diseases

Mammalian autophagy-related protein Atg8, including the LC3 subfamily and GABARAP subfamily. Atg8 proteins play a vital role in autophagy initiation, autophagosome formation and transport, and autophagy-lysosome fusion. GABARAP subfamily proteins (GABARAPs) share a high degree of homology with LC3 family proteins, and their unique roles are often overlooked. GABARAPs are as indispensable as LC3 in autophagy. Deletion of GABARAPs fails autophagy flux induction and autophagy lysosomal fusion, which leads to the failure of autophagy. GABARAPs are also involved in the transport of selective autophagy receptors. They are engaged in various particular autophagy processes, including mitochondrial autophagy, endoplasmic reticulum autophagy, Golgi autophagy, centrosome autophagy, and dorphagy. Furthermore, GABARAPs are closely related to the transport and delivery of the inhibitory neurotransmitter γ-GABA_A and the angiotensin II AT1 receptor (AT1R), tumor growth, metastasis, and prognosis. GABARAPs also have been confirmed to be involved in various diseases, such as cancer, cardiovascular disease, and neurodegenerative diseases. In order to better understand the role and therapeutic potential of GABARAPs, this article comprehensively reviews the autophagic and non-autophagic functions of GABARAPs, as well as the research progress of the role and mechanism of GABARAPs in cancer, cardiovascular diseases and neurodegenerative diseases. It emphasizes the significance of GABARAPs in the clinical prevention and treatment of diseases, and may provide new therapeutic ideas and targets for human diseases. GABARAP and GABARAPL1 in the serum of cancer patients are positively correlated with the prognosis of patients, which can be used as a clinical biomarker, predictor and potential therapeutic target. GABARAP family proteins: autophagy and non-autophagy related functions in diseases. By Figdraw ( https://www.figdraw.com ).

The Role of mTORC1 Pathway and Autophagy in Resistance to Platinum-Based Chemotherapeutics

Cisplatin (cis-diamminedichloroplatinum I) is a platinum-based drug, the mainstay of anticancer treatment for numerous solid tumors. Since its approval by the FDA in 1978, the drug has continued to be used for the treatment of half of epithelial cancers. However, resistance to cisplatin represents a major obstacle during anticancer therapy. Here, we review recent findings on how the mTORC1 pathway and autophagy can influence cisplatin sensitivity and resistance and how these data can be applicable for the development of new therapeutic strategies.

Update on Autophagy Inhibitors in Cancer: Opening up to a Therapeutic Combination with Immune Checkpoint Inhibitors

Autophagy is a highly conserved and natural degradation process that helps maintain cell homeostasis through the elimination of old, worn, and defective cellular components, ensuring proper cell energy intake. The degradative pathway constitutes a protective barrier against diverse human diseases including cancer. Autophagy basal level has been reported to be completely dysregulated during the entire oncogenic process. Autophagy influences not only cancer initiation, development, and maintenance but also regulates cancer response to therapy. Currently, autophagy inhibitor candidates mainly target the early autophagy process without any successful preclinical/clinical development. Lessons learned from autophagy pharmaceutical manipulation as a curative option progressively help to improve drug design and to encounter new targets of interest. Combinatorial strategies with autophagy modulators are supported by abundant evidence, especially dealing with immune checkpoint inhibitors, for which encouraging preclinical results have been recently published. GNS561, a PPT1 inhibitor, is a promising autophagy modulator as it has started a phase 2 clinical trial in liver cancer indication, combined with atezolizumab and bevacizumab, an assessment without precedent in the field. This approach paves a new road, leading to the resurgence of anticancer autophagy inhibitors as an attractive therapeutic target in cancer.

ATHENA: an independently validated autophagy-related epigenetic prognostic prediction model of head and neck squamous cell carcinoma

The majority of these existing prognostic models of head and neck squamous cell carcinoma (HNSCC) have unsatisfactory prediction accuracy since they solely utilize demographic and clinical information. Leveraged by autophagy-related epigenetic biomarkers, we aim to develop a better prognostic prediction model of HNSCC incorporating CpG probes with either main effects or gene-gene interactions. Based on DNA methylation data from three independent cohorts, we applied a 3-D analysis strategy to develop An independently validated auTophagy-related epigenetic prognostic prediction model of HEad and Neck squamous cell carcinomA (ATHENA). Compared to prediction models with only demographic and clinical information, ATHENA has substantially improved discriminative ability, prediction accuracy and more clinical net benefits, and shows robustness in different subpopulations, as well as external populations. Besides, epigenetic score of ATHENA is significantly associated with tumor immune microenvironment, tumor-infiltrating immune cell abundances, immune checkpoints, somatic mutation and immunity-related drugs. Taken together these results, ATHENA has the demonstrated feasibility and utility of predicting HNSCC survival ( http://bigdata.njmu.edu.cn/ATHENA/ ).

Autophagy characteristics of phytoestrogens in management and prevention of diseases: A narrative review of in-vivo and in-vitro studies

Phytoestrogens are non-steroid polyphenolic materials present in 300 plants. Regarding their structural similarities to estradiol, phytoestrogens attach to estrogen receptors and display anti- or pro-estrogenic activities. This review explored phytoestrogens' potential advantages and autophagy properties in light of their future application for disease management, highlighting how phytoestrogens could modulate autophagy. Research has examined the prospective benefits of phytoestrogens for the anticipation and management of various conditions, including signs of menopause, tumors, skin deterioration, osteoporosis, heart disease, neurodegenerative conditions, disorders of the immune system, and metabolic syndrome, owing to their therapeutic effects. As phytoestrogens can activate or inhibit autophagy, which has antioxidant, apoptotic, anti-mutagenic, anticancer, transcriptional, and genomic impacts on cancer and aging illnesses, phytoestrogens could influence diseases through the modulation of autophagy. The collaborative research on animal models, utilization of genetic techniques, and administration of pharmacologically active substances has indicated the possible therapeutic benefits of autophagy modulation in various illnesses. Further research is required to illustrate the pathways by which phytoestrogens modulate autophagy and the possible therapeutic effects on these diseases.

Protein Aggregates and Aggrephagy in Myopathies

A number of muscular disorders are hallmarked by the aggregation of misfolded proteins within muscle fibers. A specialized form of macroautophagy, termed aggrephagy, is designated to remove and degrade protein aggregates. This review aims to summarize what has been studied so far about the direct involvement of aggrephagy and the activation of the key players, among others, p62, NBR1, Alfy, Tollip, Optineurin, TAX1BP1 and CCT2 in muscular diseases. In the first part of the review, we describe the aggrephagy pathway with the involved proteins; then, we illustrate the muscular disorder histologically characterized by protein aggregates, highlighting the role of aggrephagy pathway abnormalities in these muscular disorders.

Pathogenic mechanisms of glucocorticoid-induced osteoporosis

Glucocorticoid (GC) is one of the most prescribed medicines to treat various inflammatory and autoimmune diseases. However, high doses and long-term use of GCs lead to multiple adverse effects, particularly glucocorticoid-induced osteoporosis (GIO). Excessive GCs exert detrimental effects on bone cells, including osteoblasts, osteoclasts, and osteocytes, leading to impaired bone formation and resorption. The actions of exogenous GCs are considered to be strongly cell-type and dose dependent. GC excess inhibits the proliferation and differentiation of osteoblasts and enhances the apoptosis of osteoblasts and osteocytes, eventually contributing to reduced bone formation. Effects of GC excess on osteoclasts mainly include enhanced osteoclastogenesis, increased lifespan and number of mature osteoclasts, and diminished osteoclast apoptosis, which result in increased bone resorption. Furthermore, GCs have an impact on the secretion of bone cells, subsequently disturbing the process of osteoblastogenesis and osteoclastogenesis. This review provides timely update and summary of recent discoveries in the field of GIO, with a particular focus on the effects of exogenous GCs on bone cells and the crosstalk among them under GC excess.

Autophagy, a relevant process for metabolic health and type-2 diabetes

Autophagy is a very active process that plays an important role in cell and organ differentiation and remodelling, being a crucial system to guarantee health. This physiological process is activated in starvation and inhibited in the presence of nutrients. This short review comments on the three types of autophagy: macroautophagy, microautophagy, and chaperone-mediated autophagy, as well as different aspects that control autophagy and its relationship with health and degenerative diseases. As autophagy is highly dependent on functional autophagy (ATG) proteins integrating the phagophore, the role of some key ATG genes and epigenes are briefly commented on. The manuscript deepens discussing some central aspects of type-2 diabetes mellitus and their relationship with the cell cleaning process and mitochondria homeostasis maintenance, as well as the mechanisms through which antidiabetic drugs affect autophagy. Well-designed studies are needed to elucidate whether autophagy plays a casual or causal role in T2DM.

Identification of autophagy-related genes in neuropathic pain through bioinformatic analysis

BACKGROUND

Neuropathic pain (NP) is one of the most common types of chronic pain and significantly compromises the quality of life. Autophagy is an intracellular catabolic process that is required to maintain cellular homeostasis in response to various stresses. The role of autophagy-related genes in the diagnosis and treatment of neuropathic pain remains unclear.

METHODS

We identified autophagy-related differentially expressed genes (ARDEGs) and differentially expressed miRNAs (DE-miRNAs) in neuropathic pain by bioinformatics analysis of the GSE145226 and GSE145199 datasets. These ARDEGs and their co-expressed genes were subjected to Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis, Gene Set Enrichment Analysis (GSEA) and friends analysis. Meanwhile, we constructed TFs-ARDEGs, miRNA-ARDEGs regulatory network through ChIPBase database and the HTFtarget database, multiMir R package. Finally, we performed immune infiltration analysis of ARDEGs by Single Sample Gene Set Enrichment Analysis (ssGSEA).

RESULTS

We identified 2 potential autophagy-related differentially expressed genes (Sirt2 and ST7) that may be closely associated with the pathogenesis of neuropathic pain. GO, KEGG and GSEA analysis revealed that these two ARDEGs were mainly enriched in pyridine nucleotide metabolic process, nicotinamide nucleotide metabolic process, Nicotinate and nicotinamide metabolism, NF-κB pathway, KRAS signaling, P53 pathway. In the TFs-ARDEGs and miRNA-ARDEGs regulatory network, miR-140-5p and Cebpb were predicted to be as crucial regulators in the progression of NP. For the ssGSEA results, Sirt2 was positively correlated with Eosinophil and Effector memory CD8⁺ T cell infiltration, which suggested that it may be involved in the regulation of neuroimmune-related signaling.

CONCLUSION

Two autophagy-related differentially expressed genes, especially Sirt2, may be potential biomarkers for NP, providing more evidence about the crucial role of autophagy in neuropathic pain.

Neutrophil autophagy and NETosis in COVID-19: perspectives

The COVID-19 pandemic has caused substantial losses worldwide in people's lives, health, and property. Currently, COVID-19 is still prominent worldwide without any specific drug treatment. The SARS-CoV-2 pathogen is the cause of various systemic diseases, mainly acute pneumonia. Within the pathological process, neutrophils are recruited to infected sites, especially in the lungs, for the first stage of removing invading SARS-CoV-2 through a range of mechanisms. Macroautophagy/autophagy, a conserved autodegradation process in neutrophils, plays a crucial role in the neutrophil phagocytosis of pathogens. NETosis refers to neutrophil cell death, while auto-inflammatory factors and antigens release NETs. This review summarizes the latest research progress and provides an in-depth explanation of the underlying mechanisms of autophagy and NETosis in COVID-19. Furthermore, after exploring the relationship between autophagy and NETosis, we discuss potential targets and treatment options. This review keeps up with the latest research on COVID-19 from neutrophil autophagy and NETosis with a new perspective, which can guide the urgent development of antiviral drugs and provide guidance for the clinical treatment of COVID-19.Abbreviations: AKT1: AKT serine/threonine kinase 1; AMPK: AMP-activated protein kinase; AP: autophagosome; ARDS: acute respiratory distress syndrome; ATG: autophagy related; BECN1: beclin 1; cfDNA: cell-free DNA; COVID-19: coronavirus disease 2019; CQ: chloroquine; DMVs: double-membrane vesicles; ELANE/NE: elastase, neutrophil expressed; F3: coagulation factor III, tissue factor; HCQ: hydroxychloroquine; MAP1LC3/LC3: microtubule associated protein 1 light chain of 3; MPO: myeloperoxidase; MTORC1: mechanistic target of rapamycin kinase complex 1; NETs: neutrophil traps; NSP: nonstructural protein; PI3K: class I phosphoinositide 3-kinase; PtdIns3K: class III phosphatidylinositol 3-kinase; PtdIns3P: phosphatidylinositol-3-phosphate; ROS: reactive oxygen species; SARS-CoV-2: severe acute respiratory syndrome coronavirus 2; SKP2: S-phase kinase associated protein 2; TCC: terminal complement complex; ULK1: unc-51 like.

MTOR gene polymorphism may be associated with microscopic polyangiitis susceptibility in a Guangxi population of China

OBJECTIVE

Microscopic polyangiitis (MPA) onset is affected by genetic predisposition. Autophagy plays a certain role in antineutrophil cytoplasmic antibody-associated vasculitis developing. A key factor in autophagy regulating, the genetic polymorphism of MTOR gene is essential. The objective was to explore the associations between MTOR gene polymorphism and MPA susceptibility in a Guangxi population of China.

METHODS

A sum of 208 MPA cases and 209 healthy volunteers from Guangxi in this case-control study, four important single nucleotide polymorphism (SNP) loci of MTOR gene including rs3806317, rs1064261, rs1883965 and rs2295080 were examined. Multiplex polymerase chain reaction combined with high-throughput sequencing was performed. Subgroup analysis was evaluated by gender and ethnicity. Linkage disequilibrium and haplotype analysis were tested. Multi-SNPs interaction among mTOR signaling pathway was assessed.

RESULTS

For rs2295080, homozygous mutant GG genotype was associated with a decreased susceptibility of MPA in recessive model (OR = 0.38, 95%CI: 0.14-1.00, p = 0.040), particularly in the subgroup of female (OR = 0.16, 95%CI: 0.03-0.74, p = 0.006) and Han population (OR = 0.32, 95%CI: 0.10-1.00, p = 0.034). Individual carrying G allele was linked with decreasing MPA susceptibility in Han population of Guangxi (OR = 0.65, 95%CI: 0.44-0.97, p = 0.036). In haplotype analysis, the haplotype AAT was correlated with increasing susceptibility of MPA (OR = 1.347, 95%CI: 1.004-1.807, p = 0.046). Moreover, in the multi-SNPs interaction analysis, the six-locus model was identified as the best interaction model (p < 0.05).

CONCLUSION

These findings suggest that rs2295080 polymorphism of MTOR gene may be associated with MPA susceptibility in a Guangxi population of China and G allele might be an important protective factor.

Toward effective Atg8-based ATTECs: Approaches and perspectives

Induction of Atg8-family protein (LC3/GABARAP proteins in human) interactions with target proteins of interest by proximity-inducing small molecules offers the possibility for novel targeted protein degradation approaches. However, despite intensive screening campaigns during the last 5 years, no potent ligands for LC3/GABARAPs have been developed, rendering this approach largely unexplored and unsuitable for therapeutic exploitation. In this Viewpoint, we analyze the reported attempts identifying LC3/GABARAP inhibitors and provide our own point of view why no potent inhibitors have been found. Additionally, we designate reasonable directions for the identification of potent and probably selective LC3/GABARAP inhibitors for alternative therapeutic applications.

Recent Update and Drug Target in Molecular and Pharmacological Insights into Autophagy Modulation in Cancer Treatment and Future Progress

Recent evidence suggests that autophagy is a governed catabolic framework enabling the recycling of nutrients from injured organelles and other cellular constituents via a lysosomal breakdown. This mechanism has been associated with the development of various pathologic conditions, including cancer and neurological disorders; however, recently updated studies have indicated that autophagy plays a dual role in cancer, acting as a cytoprotective or cytotoxic mechanism. Numerous preclinical and clinical investigations have shown that inhibiting autophagy enhances an anticancer medicine's effectiveness in various malignancies. Autophagy antagonists, including chloroquine and hydroxychloroquine, have previously been authorized in clinical trials, encouraging the development of medication-combination therapies targeting the autophagic processes for cancer. In this review, we provide an update on the recent research examining the anticancer efficacy of combining drugs that activate cytoprotective autophagy with autophagy inhibitors. Additionally, we highlight the difficulties and progress toward using cytoprotective autophagy targeting as a cancer treatment strategy. Importantly, we must enable the use of suitable autophagy inhibitors and coadministration delivery systems in conjunction with anticancer agents. Therefore, this review briefly summarizes the general molecular process behind autophagy and its bifunctional role that is important in cancer suppression and in encouraging tumor growth and resistance to chemotherapy and metastasis regulation. We then emphasize how autophagy and cancer cells interacting with one another is a promising therapeutic target in cancer treatment.

Association between autophagy and acute pancreatitis

Autophagy pathway involves maintaining intracellular homeostasis by regulating the degradation of cytoplasmic components. Disfunction of autophagic process has been confirmed to be critical mechanism in many diseases, including cancer, inflammation, infection, degeneration and metabolic disorders. Recent studies have shown that autophagy is one of the early events in acute pancreatitis. Impaired autophagy promotes the abnormal activation of zymogen granules and results in apoptosis and necrosis of exocrine pancreas. Furthermore, multiple signal paths involve progression of acute pancreatitis by regulating autophagy pathway. This article provides a comprehensive review of the recent advances in epigenetic regulation of autophagy and the role of autophagy in acute pancreatitis.

Small Molecule Inhibitors for Unc-51-like Autophagy-Activating Kinase Targeting Autophagy in Cancer

Autophagy is a cellular process that removes damaged components of cells and recycles them as biochemical building blocks. Autophagy can also be induced to protect cells in response to intra- and extracellular stresses, including damage to cellular components, nutrient deprivation, hypoxia, and pathogenic invasion. Dysregulation of autophagy has been attributed to various diseases. In particular, autophagy protects cancer cells by supporting tumor cell survival and the development of drug resistance. Understanding the pathophysiological mechanisms of autophagy in cancer has stimulated the research on discovery and development of specific inhibitors targeting various stages of autophagy. In recent years, Unc-51-like autophagy-activating kinase (ULK) inhibitors have become an attractive strategy to treat cancer. This review summarizes recent discoveries and developments in small-molecule ULK inhibitors and their potential as anticancer agents. We focused on structural features, interactions with binding sites, and biological effects of these inhibitors. Overall, this review will provide guidance for using ULK inhibitors as chemical probes for autophagy in various cancers and developing improved ULK inhibitors that would enhance therapeutic benefits in the clinic.

Editorial: Highlights in Autophagy-From Basic Mechanisms to Human Disorder Treatments

Autophagy is an evolutionarily conserved catabolic process and represents a field of research that is constantly growing [...].

Pharmacological Progress of Mitophagy Regulation

With the advancement in novel drug discovery, biologically active compounds are considered pharmacological tools to understand complex biological mechanisms and the identification of potent therapeutic agents. Mitochondria boast a central role in different integral biological processes and mitochondrial dysfunction is associated with multiple pathologies. It is, therefore, prudent to target mitochondrial quality control mechanisms by using pharmacological approaches. However, there is a scarcity of biologically active molecules, which can interact with mitochondria directly. Currently, the chemical compounds used to induce mitophagy include oligomycin and antimycin A for impaired respiration and acute dissipation of mitochondrial membrane potential by using CCCP/FCCP, the mitochondrial uncouplers. These chemical probes alter the homeostasis of the mitochondria and limit our understanding of the energy regulatory mechanisms. Efforts are underway to find molecules that can bring about selective removal of defective mitochondria without compromising normal mitochondrial respiration. In this report, we have tried to summarize and status of the recently reported modulators of mitophagy.