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The progression and malignancy of many tumors are associated with increased tissue stiffness. Conversely, the oncogenically transformed cells can be confined in soft stroma. Yet, the underlying mechanisms by which soft matrix confines tumorigenesis and metastasis remain elusive. Here, we show that pancreatic cancer cells are suppressed in the soft extracellular matrix, which is associated with YAP1 degradation through autophagic-lysosomal pathway rather than Hippo signal mediated proteasome pathway. In the soft stroma, PTEN is upregulated and activated, which consequently promotes lysosomal biogenesis, leading to the activation of cysteine-cathepsins for YAP1 degradation. In vitro, purified cathepsin L can directly digest YAP1 under acidic conditions. Lysosomal stress, either caused by chloroquine or overexpression of cystatin A/B, results in YAP1 accumulation and malignant transformation. Likewise, liver fibrosis induced stiffness can promote malignant potential in mice. Clinical data show that down-regulation of lysosomal biogenesis is associated with pancreatic fibrosis and stiffness, YAP1 accumulation, and poor prognosis in PDAC patients. Together, our findings suggest that soft stroma triggers lysosomal flux-mediated YAP1 degradation and induces cancer cell dormancy.

The crosstalk between clathrin-mediated endocytosis (CME) and the autophagy pathway has been reported in mammals; however, the interconnection of CME with autophagy has not been established in plants. Here, we report that the Arabidopsis CLATHRIN LIGHT CHAIN (CLC) subunit 2 and 3 double mutant, clc2-1 clc3-1, phenocopies Arabidopsis AUTOPHAGY-RELATED GENE (ATG) mutants in both autoimmunity and nutrient sensitivity. Accordingly, the autophagy pathway is significantly compromised in the clc2-1 clc3-1 mutant. Interestingly, multiple assays demonstrate that CLC2 directly interacts with ATG8h/ATG8i in a domain-specific manner. As expected, both GFP-ATG8h/GFP-ATG8i and CLC2-GFP are subjected to autophagic degradation, and degradation of GFP-ATG8h is significantly reduced in the clc2-1 clc3-1 mutant. Notably, simultaneous knockout of ATG8h and ATG8i by CRISPR-Cas9 results in enhanced resistance against Golovinomyces cichoracearum, supporting the functional relevance of the CLC2-ATG8h/8i interactions. In conclusion, our results reveal a link between the function of CLCs and the autophagy pathway in Arabidopsis.

Understanding the normal function of the Huntingtin (HTT) protein is of significance in the design and implementation of therapeutic strategies for Huntington's disease (HD). Expansion of the CAG repeat in the HTT gene, encoding an expanded polyglutamine (polyQ) repeat within the HTT protein, causes HD and may compromise HTT's normal activity contributing to HD pathology. Here, we investigated the previously defined role of HTT in autophagy specifically through studying HTT's association with ubiquitin. We find that HTT interacts directly with ubiquitin in vitro. Tandem affinity purification was used to identify ubiquitinated and ubiquitin-associated proteins that copurify with a HTT N-terminal fragment under basal conditions. Copurification is enhanced by HTT polyQ expansion and reduced by mimicking HTT serine 421 phosphorylation. The identified HTT-interacting proteins include RNA-binding proteins (RBPs) involved in mRNA translation, proteins enriched in stress granules, the nuclear proteome, the defective ribosomal products (DRiPs) proteome and the brain-derived autophagosomal proteome. To determine whether the proteins interacting with HTT are autophagic targets, HTT knockout (KO) cells and immunoprecipitation of lysosomes were used to investigate autophagy in the absence of HTT. HTT KO was associated with reduced abundance of mitochondrial proteins in the lysosome, indicating a potential compromise in basal mitophagy, and increased lysosomal abundance of RBPs which may result from compensatory up-regulation of starvation-induced macroautophagy. We suggest HTT is critical for appropriate basal clearance of mitochondrial proteins and RBPs, hence reduced HTT proteostatic function with mutation may contribute to the neuropathology of HD.

The etiology of preeclampsia (PE), a severe complication of pregnancy with several clinical manifestations and a high incidence of maternal and fetal morbidity and mortality, remains unclear. This issue is a major hurdle for effective treatment strategies. We recently demonstrated that PE exhibits an Alzheimer-like etiology of impaired autophagy and proteinopathy in the placenta. Targeting of these pathological pathways may be a novel therapeutic strategy for PE. Stimulation of autophagy with the natural disaccharide trehalose and its lacto analog lactotrehalose in hypoxia-exposed primary human trophoblasts restored autophagy, inhibited the accumulation of toxic protein aggregates, and restored the ultrastructural features of autophagosomes and autolysosomes. Importantly, trehalose and lactotrehalose inhibited the onset of PE-like features in a humanized mouse model by normalizing autophagy and inhibiting protein aggregation in the placenta. These disaccharides restored the autophagy-lysosomal biogenesis machinery by increasing nuclear translocation of the master transcriptional regulator TFEB. RNA-seq analysis of the placentas of mice with PE indicated the normalization of the PE-associated transcriptome profile in response to trehalose and lactotrehalose. In summary, our results provide a novel molecular rationale for impaired autophagy and proteinopathy in patients with PE and identify treatment with trehalose and its lacto analog as promising therapeutic options for this severe pregnancy complication.

The ability of neurons to rapidly remodel their synaptic structure and strength in response to neuronal activity is highly conserved across species and crucial for complex brain functions. However, mechanisms required to elicit and coordinate the acute, activity-dependent structural changes across synapses are not well understood, as neurodevelopment and structural plasticity are tightly linked. Here, using an RNAi screen in Drosophila against genes affecting nervous system functions in humans, we uncouple cellular processes important for synaptic plasticity and synapse development. We find mutations associated with neurodegenerative and mental health disorders are 2-times more likely to affect activity-induced synaptic remodeling than synapse development. We report that while both synapse development and activity-induced synaptic remodeling at the fly NMJ require macroautophagy (hereafter referred to as autophagy), bifurcation in the autophagy pathway differentially impacts development and synaptic plasticity. We demonstrate that neuronal activity enhances autophagy activation but diminishes degradative autophagy, thereby driving the pathway towards autophagy-based secretion. Presynaptic knockdown of Snap29, Sec22, or Rab8, proteins implicated in the secretory autophagy pathway, is sufficient to abolish activity-induced synaptic remodeling. This study uncovers secretory autophagy as a transsynaptic signaling mechanism modulating synaptic plasticity.

Macroautophagy/autophagy is an essential catabolic process that targets a wide variety of cellular components including proteins, organelles, and pathogens. ATG7, a protein involved in the autophagy process, plays a crucial role in maintaining cellular homeostasis and can contribute to the development of diseases such as cancer. ATG7 initiates autophagy by facilitating the lipidation of the ATG8 proteins in the growing autophagosome membrane. The noncanonical isoform ATG7(2) is unable to perform ATG8 lipidation; however, its cellular regulation and function are unknown. Here, we uncovered a distinct regulation and function of ATG7(2) in contrast with ATG7(1), the canonical isoform. First, affinity-purification mass spectrometry analysis revealed that ATG7(2) establishes direct protein-protein interactions (PPIs) with metabolic proteins, whereas ATG7(1) primarily interacts with autophagy machinery proteins. Furthermore, we identified that ATG7(2) mediates a decrease in metabolic activity, highlighting a novel splice-dependent function of this important autophagy protein. Then, we found a divergent expression pattern of ATG7(1) and ATG7(2) across human tissues. Conclusively, our work uncovers the divergent patterns of expression, protein interactions, and function of ATG7(2) in contrast to ATG7(1). These findings suggest a molecular switch between main catabolic processes through isoform-dependent expression of a key autophagy gene.

Glycosphingolipids (GSLs) are key constituents of membrane bilayers playing a role in structural integrity, cell signalling in microdomains, endosomes and lysosomes, and cell death pathways. Conversion of ceramide into GSLs is controlled by GCS (glucosylceramide synthase) and inhibitors of this enzyme for the treatment of lipid storage disorders and specific cancers. With a diverse range of functions attributed to GSLs, the ability of the GSC inhibitor, eliglustat, to reduce myeloma bone disease was investigated. In pre-clinical models of multiple myeloma, osteoclast-driven bone loss was reduced by eliglustat in a mechanistically separate manner to zoledronic acid, a bisphosphonate that prevents osteoclast-mediated bone destruction. Autophagic degradation of TNF receptor-associated factor 3 (TRAF3), a key step for osteoclast differentiation, was inhibited by eliglustat as evidenced by TRAF3 lysosomal and cytoplasmic accumulation. By altering GSL composition, eliglustat prevented lysosomal degradation whilst exogenous addition of missing GSLs rescued TRAF3 degradation to restore osteoclast formation in bone marrow cells from myeloma patients. This work highlights the clinical potential of eliglustat as a therapy for myeloma bone disease. Furthermore, using eliglustat as a lysosomal inhibitor in osteoclasts may widen its therapeutic uses to other bone disorders such as bone metastasis, osteoporosis and inflammatory bone loss.

Macroautophagy/autophagy receptors target their substrates to phagophores for subsequent sequestration within autophagosomes. During phagophore membrane expansion in mammalian cells, autophagy receptors simultaneously interact with the ubiquitinated substrates and the LC3/GABARAP proteins on the expanding membrane. In this punctum, we summarize and discuss our recent research progress on synthetic autophagy receptors (AceTACs). The series of AceTACs were designed by engineering the essential interacting domains and motifs of SQSTM1/p62 (sequestosome 1), a major mammalian autophagy receptor. Particularly, we replaced the ubiquitin-associated domain of SQSTM1 with a target-specific antibody, redirecting the bifunctional interactions of wild-type SQSTM1 and directing the degradation target into the autophagy process. We successfully demonstrated the targeted degradation of aggregation-prone proteins using the AceTAC degraders. Moreover, we presented a model system with a guideline to induce targeted degradation of organelles through the autophagy machinery.

Autophagy in eukaryotes functions to maintain homeostasis by degradation and recycling of long-lived and unwanted cellular materials. Autophagy plays important roles in pathogenicity of various fungal pathogens, suggesting that autophagy is a novel target for development of antifungal compounds. Here, we describe bioluminescence resonance energy transfer (BRET)-based high-throughput screening (HTS) strategy to identify compounds that inhibit fungal ATG4 cysteine protease-mediated cleavage of ATG8 that is critical for autophagosome formation. We identified ebselen (EB) and its analogs ebselen oxide (EO) and 2-(4-methylphenyl)-1,2-benzisothiazol-3(2H)-one (PT) as inhibitors of fungal pathogens Botrytis cinerea and Magnaporthe oryzae ATG4-mediated ATG8 processing. The EB and its analogs inhibit spore germination, hyphal development, and appressorium formation in Ascomycota pathogens, B. cinerea, M. oryzae, Sclerotinia sclerotiorum and Monilinia fructicola. Treatment with EB and its analogs significantly reduced fungal pathogenicity. Our findings provide molecular insights to develop the next generation of antifungal compounds by targeting autophagy in important fungal pathogens.

The covalent attachment of ubiquitin-like LC3 proteins (microtubule-associated proteins 1A/1B light chain 3) prepares the autophagic membrane for cargo recruitment. We resolve key steps in LC3 lipidation by combining molecular dynamics simulations and experiments in vitro and in cellulo. We show how the E3-like ligaseautophagy-related 12 (ATG12)-ATG5-ATG16L1 in complex with the E2-like conjugase ATG3 docks LC3 onto the membrane in three steps by (i) the phosphatidylinositol 3-phosphate effector protein WD repeat domain phosphoinositide-interacting protein 2 (WIPI2), (ii) helix α2 of ATG16L1, and (iii) a membrane-interacting surface of ATG3. Phosphatidylethanolamine (PE) lipids concentrate in a region around the thioester bond between ATG3 and LC3, highlighting residues with a possible role in the catalytic transfer of LC3 to PE, including two conserved histidines. In a near-complete pathway from the initial membrane recruitment to the LC3 lipidation reaction, the three-step targeting of the ATG12-ATG5-ATG16L1 machinery establishes a high level of regulatory control.

ATG5 plays a pivotal role in membrane Atg8ylation, influencing downstream processes encompassing canonical autophagy and noncanonical processes. Remarkably, genetic ablation of ATG5 in myeloid cells leads to an exacerbated pathological state in murine models of tuberculosis, characterized by an early surge in mortality much more severe when compared to the depletion of other components involved in Atg8ylation or canonical autophagy. This study shows that in the absence of ATG5, but not other core canonical autophagy factors, endolysosomal organelles display a lysosomal hypersensitivity phenotype when subjected to damage. This is in part due to a compromised recruitment of ESCRT proteins to lysosomes in need of repair. Mechanistically, in the absence of ATG5, the ESCRT protein PDCD6IP/ALIX is sequestered by the alternative conjugate ATG12-ATG3, contributing to excessive exocytic processes while not being available for lysosomal repair. Specifically, this condition increases secretion of extracellular vesicles and particles, and leads to excessive degranulation in neutrophils. Our findings uncover unique functions of ATG5 outside of the autophagy and Atg8ylation paradigm. This finding is of in vivo relevance for tuberculosis pathogenesis as modeled in mice.Abbreviations: Atg5: autophagy related 5; ESCRT: endosomal sorting complex required for transport; EVPs: extracellular vesicles and particles; FPR1: formyl peptide receptor 1; LyHYP: lysosomal hypersensitivity phenotype; LysoIP: lysosome immunopurification; Mtb: Mycobacterium tuberculosis; ORF3a: open reading frame 3a protein; PDCD6IP/ALIX: programmed cell death 6 interacting protein; SARS-CoV-2: severe acute respiratory syndrome coronavirus 2, TFEB: transcription factor EB.

Pulmonary arterial hypertension (PAH) is a devastating and progressive disease with limited treatment options. Endothelial dysfunction plays a central role in the development and progression of PAH, yet the underlying mechanisms are incompletely understood. The endosome-lysosome system is important to maintain cellular health, and the small GTPase RAB7 regulates many functions of this system. Here, we explored the role of RAB7 in endothelial cell (EC) function and lung vascular homeostasis. We found reduced expression of RAB7 in ECs from patients with PAH. Endothelial haploinsufficiency of RAB7 caused spontaneous pulmonary hypertension (PH) in mice. Silencing of RAB7 in ECs induced broad changes in gene expression revealed via RNA-Seq, and RAB7-silenced ECs showed impaired angiogenesis and expansion of a senescent cell fraction, combined with impaired endolysosomal trafficking and degradation, suggesting inhibition of autophagy at the predegradation level. Furthermore, mitochondrial membrane potential and oxidative phosphorylation were decreased, and glycolysis was enhanced. Treatment with the RAB7 activator ML-098 reduced established PH in rats with chronic hypoxia/SU5416. In conclusion, we demonstrate for the first time to our knowledge the fundamental impairment of EC function by loss of RAB7, causing PH, and show RAB7 activation to be a potential therapeutic strategy in a preclinical model of PH.

Non-neovascular or dry age-related macular degeneration (AMD) is a multi-factorial disease with degeneration of the aging retinal-pigmented epithelium (RPE). Lysosomes play a crucial role in RPE health via phagocytosis and autophagy, which are regulated by transcription factor EB/E3 (TFEB/E3). Here, we find that increased AKT2 inhibits PGC-1α to downregulate SIRT5, which we identify as an AKT2 binding partner. Crosstalk between SIRT5 and AKT2 facilitates TFEB-dependent lysosomal function in the RPE. AKT2/SIRT5/TFEB pathway inhibition in the RPE induced lysosome/autophagy signaling abnormalities, disrupted mitochondrial function and induced release of debris contributing to drusen. Accordingly, AKT2 overexpression in the RPE caused a dry AMD-like phenotype in aging Akt2 KI mice, as evident from decline in retinal function. Importantly, we show that induced pluripotent stem cell-derived RPE encoding the major risk variant associated with AMD (complement factor H; CFH Y402H) express increased AKT2, impairing TFEB/TFE3-dependent lysosomal function. Collectively, these findings suggest that targeting the AKT2/SIRT5/TFEB pathway may be an effective therapy to delay the progression of dry AMD.

Autophagy is a form of programmed cell degradation that enables the maintenance of homeostasis in response to extracellular stress stimuli. Autophagy is primarily activated by starvation and mediates the degradation, removal, or recycling of cell cytoplasm, organelles, and intracellular components in eukaryotic cells. Autophagy is also involved in the pathogenesis of human diseases, including several cancers. Human uveal melanoma (UM) is the primary intraocular malignancy in adults and has an extremely poor prognosis; at present there are no effective therapies. Several studies have suggested that autophagy is important in UM. By understanding the mechanisms of activation of autophagy in UM it may be possible to develop biomarkers to provide more definitive disease prognoses and to identify potential drug targets for the development of new therapeutic strategies. This article reviews the current information regarding autophagy in UM that could facilitate biomarker and drug development.

The pathways that induce macroautophagy (referred to as autophagy hereafter) in response to the stress of starvation are well conserved and essential under nutrient-limiting conditions. However, less is understood about the mechanisms that modulate the autophagy response. Here we present evidence that after induction of autophagy in budding yeast septin filaments rapidly assemble into discrete patches distributed along the cell cortex. These patches gradually mature over 12 h of nutrient deprivation to form extended structures around Atg9 membranes tethered at the cortical endoplasmic reticulum, a class of membranes that are limiting for autophagosome biogenesis. Loss of cortical septin structures alters the kinetics of autophagy activation and most dramatically extends the duration of the autophagy response. In wild-type cells, diffusion of Atg9 membranes at the cell cortex undergoes transient pauses that are dependent on septins, and septins at the bud neck block the diffusion of Atg9 membranes between mother and daughter cells. We conclude that septins reorganize at the cell cortex during autophagy to locally limit access of Atg9 membranes to autophagosome assembly sites, and thus modulate the autophagy response during nutrient deprivation.

Cisplatin-evoked profound gastrointestinal symptomatology is one of the most common side effects of chemotherapy drugs, causing further gastrointestinal cell and intestinal mucosal injury. Ginsenoside Rh4 (G-Rh4), an active component extracted from red ginseng, possesses beneficial anti-oxidative and anti-apoptosis effects. This study aimed to assess the effectiveness of pharmacological intervention with G-Rh4 mitigating intestinal toxicity evoked by cisplatin in a murine model and in IEC-6 cells in vitro. Following oral administration for 10 days, G-Rh4 (10mg/kg and 20mg/kg) significantly increased the indicators of diamine oxidase (DAO) affected by cisplatin (20mg/kg) in mice, and histopathological analysis further indicated that G-Rh4 could effectively improve intestinal tissue morphology, as well as the expression of peroxisome proliferator-activated receptor-gamma coactivator 1 α (PGC-1α) pathway and autophagy-related proteins. Moreover, in vitro experiments demonstrated that G-Rh4 exerted a concentration-dependent increase in cell viability, while also inhibiting cytotoxicity and abnormal rise of reactive oxygen species (ROS). Notably, ROS also activate PGC-1α protein and mediate the occurrence of mitochondrial autophagy and apoptosis pathways. The molecular docking approach was employed to dock G-Rh4 with PGC-1α and AMPK, revealing a binding energy of −7.3kcal/mol and −8.1kcal/mol and indicating a tight interaction between the components and the target. G-Rh4 could reduce the expression of autophagy-related protein p62/p53, reduce the accumulation of autophagy products, and promote the flow of autophagy. In conclusion, G-Rh4 exerted protective effects against cisplatin-induced intestinal toxicity, at least partially through PGC-1α-mediated autophagy and apoptosis. [ABSTRACT FROM AUTHOR]

Kaposi's sarcoma-associated herpesvirus (KSHV) establishes a latent infection, and viral genes are poised to be transcribed in the latent chromatin. In the poised chromatins, KSHV latency-associated nuclear antigen (LANA) interacts with cellular chromodomain-helicase-DNA-binding protein 4 (CHD4) and inhibits viral promoter activation. CHD4 is known to regulate cell differentiation by preventing enhancers from activating promoters. Here, we identified a putative CHD4 inhibitor peptide (VGN73) from the LANA sequence corresponding to the LANA-CHD4 interaction surface. The VGN73 interacts with CHD4 at its PHD domain with a dissociation constant (K D) of 14 nM. Pre-treatment with VGN73 enhanced monocyte differentiation into macrophages and globally altered the repertoire of activated genes in U937 cells. Furthermore, the introduction of the peptide into the cancer cells induced caspase-mediated CHD4 cleavage, triggered cell death, and inhibited tumor growth in a xenograft mouse model. The VGN73 may facilitate cell differentiation therapy. [Display omitted] • VGN73 derived from KSHV LANA protein sequence interacts with and induces CHD4 cleavage • LANA peptide induces cell apoptosis and autophagy by CHD4 cleavage • VGN73 facilitates transcription reprogramming of monocytes • VGN73 prevents primary effusion lymphoma cell growth in a xenograft model Miura et al. identify a small peptide, derived from the KSHV LANA protein sequence, that enhances monocyte differentiation into macrophages. The introduction of the peptide into cancer cells induces CHD4 protein cleavage, triggers cell death, and inhibits tumor growth in a xenograft mouse model. [ABSTRACT FROM AUTHOR]

Mitophagy degrades damaged mitochondria, but we show here that it can also target functional mitochondria. This latter scenario occurs during programmed mitophagy and involves the mitophagy receptors NIX and BNIP3. Although AMP-activated protein kinase (AMPK), the energy-sensing protein kinase, can influence damaged-induced mitophagy, its role in programmed mitophagy is unclear. We found that AMPK directly inhibits NIX-dependent mitophagy by triggering 14-3-3-mediated sequestration of ULK1, via ULK1 phosphorylation at two sites: Ser556 and an additional identified site, Ser694. By contrast, AMPK activation increases Parkin phosphorylation and enhances the rate of depolarization-induced mitophagy, independently of ULK1. We show that this happens both in cultured cells and tissues in vivo , using the mito -QC mouse model. Our work unveils a mechanism whereby AMPK activation downregulates mitophagy of functional mitochondria but enhances that of dysfunctional/damaged ones. [Display omitted] • AMPK activation blocks NIX-dependent mitophagy • AMPK phosphorylates ULK1 to trigger inhibitory 14-3-3 binding • NIX-dependent mitophagy can target functioning mitochondria • Parkin-dependent mitophagy is enhanced by AMPK independently of ULK1 Under energetic stress, it is essential to balance dysfunctional versus healthy mitochondrial turnover. Longo and Bishnu et al. uncover a mechanism by which AMPK activation achieves this. They find that although AMPK enhances Parkin-mediated mitophagy upon mitochondrial damage, it blocks NIX-mediated mitophagy, which they now show can target functioning mitochondria. [ABSTRACT FROM AUTHOR]

Lipophagy is a ubiquitous mechanism for degradation of lipid droplets (LDs) in lysosomes. Autophagy receptors selectively target organelles for lysosomal degradation. The selective receptor for lipophagy remains elusive. Using mouse liver phosphoproteomics and human liver transcriptomics, we identify vacuolar-protein-sorting-associated protein 4A (VPS4A), a member of a large family AAA+ ATPases, as a selective receptor for lipophagy. We show that phosphorylation of VPS4A on Ser95,97 and its localization to LDs in response to fasting drives lipophagy. Imaging/three-dimensional (3D) reconstruction and biochemical analyses reveal the concomitant degradation of VPS4A and LDs in lysosomes in an autophagy-gene-7-sensitive manner. Either silencing VPS4A or targeting VPS4AS95,S97 phosphorylation or VPS4A binding to LDs or LC3 blocks lipophagy without affecting other forms of selective autophagy. Finally, VPS4A levels and markers of lipophagy are markedly reduced in human steatotic livers—revealing a fundamental role of VPS4A as the lipophagy receptor in mice and humans. [Display omitted] • Fasting induces phosphorylation of VPS4A on lipid droplets (LDs) • Phosphorylated VPS4A interacts with LC3 • VPS4A regulates lysosomal LD degradation without affecting mitophagy or ERphagy • Loss of VPS4A leads to hepatic steatosis in mice and correlates with human MASLD Das et al. show that VPS4A regulates lysosomal LD turnover independent of its canonical endosomal function. Phosphorylated VPS4A tethers LDs to LC3, facilitating selective lipophagy. VPS4A levels correlate inversely with lipophagy in human metabolic-dysfunction-associated steatotic liver disease, revealing itself as a selective receptor for lipophagy in mouse and humans. [ABSTRACT FROM AUTHOR]

Gastric cancer (GC) is a leading cause of cancer-related mortality, with a high rate of postoperative recurrence and poor long-term survival. The Eyes Absent (EYA) protein family plays a significant role in cancer progression, with EYA3 being implicated in promoting GC cell proliferation and tumor growth. Utilizing the DepMap database, we identified EYA3 as a gene of interest in GC. We analyzed EYA3 expression in GC tissues and cell lines, performed in vitro assays to assess its role in cell proliferation, and conducted gene set enrichment analysis to explore its relationship with autophagy and the mTORC1 signaling pathway. In vivo, we used a xenograft tumor model to examine the effects of EYA3 expression on tumor progression. EYA3 was consistently upregulated in GC tissues, and its high expression correlated with a decrease in patient survival rates. Silencing EYA3 in GC cell lines resulted in reduced cell proliferation. Inhibition of autophagy and activation of the mTORC1 signaling pathway were observed as mechanisms by which EYA3 may promote GC cell growth. In vivo experiments supported the in vitro findings, showing slower tumor growth with reduced EYA3 expression. Our study confirms the upregulation of EYA3 in GC and its association with poor prognosis. EYA3 promotes GC cell proliferation and tumor growth by activating the mTORC1 signaling pathway and inhibiting autophagy. These findings highlight the potential of EYA3 as a therapeutic target for GC, providing a foundation for future research and treatment strategies. Despite the promising data, the limitations of sample size and the need for further mechanistic studies are acknowledged. [ABSTRACT FROM AUTHOR]

Autophagy is a highly conserved 'self-digesting' mechanism used in eukaryotes to degrade and recycle cellular components by enclosing them in a double membrane compartment and delivering them to lytic organelles (lysosomes or vacuoles). Extensive studies in plants have revealed how autophagy is intricately linked to essential aspects of metabolism and growth, in both normal and stress conditions, including cellular and organelle homeostasis, nutrient recycling, development, responses to biotic and abiotic stresses, senescence and cell death. However, knowledge regarding autophagic processes in other photosynthetic organisms remains limited. In this review, we attempt to summarize the current understanding of autophagy in algae from a metabolic, molecular and evolutionary perspective. We focus on the composition and conservation of the autophagy molecular machinery in eukaryotes and discuss the role of autophagy in metabolic regulation, cellular homeostasis and stress adaptation in algae. This article is part of the theme issue 'The evolution of plant metabolism'. [ABSTRACT FROM AUTHOR]

BACKGROUND:Autophagy and ferroptosis play important roles in the development of chronic kidney disease, but the molecular mechanisms and gene targets related to autophagy and ferroptosis in renal tissue of chronic kidney disease are still unclear. OBJECTIVE:To screen differentially expressed genes in chronic kidney disease-related datasets based on bioinformatics, and to explore potential key biomarkers suitable for screening renal function progression in patients with chronic kidney disease. METHODS: The GSE137570 dataset was obtained from GEO database to screen the differentially expressed genes by Networkanalyst database analysis. Ferroptosis and autophagy related targets were obtained by OMIM, GENECARD, FerrDb and HAMdb databases. The respective data were intersected to obtain autophagy-ferroptosis related differentially expressed genes in chronic kidney disease for parallel enrichment analysis. The STRING website was used to construct the protein-protein interaction network of differentially expressed genes, which was imported into Cytoscape software and analyzed by MCODEand Cytohubba plug-in to screen potential core targets. Enrichment analysis was performed to obtain the functions of these potential core targets. In the in vitro experiment, mouse renal tubular epithelial cells were divided into two groups:the control group received no intervention, while the model group was stimulated with 5 ng/mL transforming growth factor β1 for 24 hours to induce mesenchymal transformation of renal tubular epithelial cells. Flow cytometry was used to measure the levels of reactive oxygen species and changes in mitochondrial membrane potential in the cells. RT-PCR was employed to assess ferroptosis, autophagy-related markers, and the mRNA expression of potential core targets in the cells. RESULTS AND CONCLUSION:After screening the GSE137570 dataset, a total of 480 differentially expressed genes were obtained, including 104 upregulated genes and 376 downregulated genes (log2| (FC)|＞1, P＜0. 05). There were 562 ferroptosis-related targets and 1 266 autophagy-related targets obtained from the OMIM, GENECARD, FerrDb, and HAMdb databases. Intersection of differentially expressed genes with ferroptosis-and autophagy-related targets yielded15 ferroptosis-related targets and 18 autophagy-related targets, respectively. The enrichment analysis results indicate that ferroptosis-related differentially expressed genes are primarily involved in biological processes such as sulfur amino acid metabolism, neutrophil degranulation, and ferroptosis signaling pathways. Autophagy-related differentially expressed genes are mainly enriched in biological processes such as platelet degranulation, extracellular matrix degradation, and receptor tyrosine kinase signaling. After screened by MCODE and CytoHubba, key genes were identified in the protein-protein interaction network, including CD44, ALB, TIMP1, PLG, CCL2, and DPP4. Immune infiltration analysis results indicate that immune cells such as B cells, CD4+T cells, NK cells, and monocytes show significant differential expression in renal tissue after chronic kidney disease, and the core targets are also significantly correlated with these immune cells (P＜0. 05). The results of receiver operator characteristic curve analysis further demonstrate that the pathological progression of chronic kidney disease can be effectively diagnosed by CD44, ALB, TIMP1, PLG, CCL2, and DPP4. Single-cell sequencing results show that, except for PLG, the expression of target genes in the renal tissue of mice in each model group is generally consistent with the results of this experiment. RT-PCR results demonstrate that, for the validation of autophagy and ferroptosis phenotypes, compared with the control group, the model group shows a significant decrease in mRNA expression of LC3B, Nrf2, and SLC7A11 (P＜0. 05), and a significant increase in P62 mRNA expression (P＜0. 05). Regarding the validation of potential core targets, compared with the control group, the model group exhibits a significant decrease in mRNA expression of ALB and PLG (P＜0. 05), and a significant increase in TIMP1 and CCL2 mRNA expression (P＜0. 05). Overall, these findings indicate that, through bioinformatics analysis and experimental validation, CD44, ALB, TIMP1, PLG, and CCL2 are abnormally expressed in the renal tissue of patients with chronic kidney disease, closely correlated with estimated glomerular filtration rate and tubulointerstitial fibrosis, and maybe play a predictive role in the progression of chronic kidney disease [ABSTRACT FROM AUTHOR]

This paper provides an exhaustive overview of the intricate interplay between microRNAs (miRNAs) and autophagy in the context of human cancers, underscoring the pivotal role these non-coding RNAs play in modulating autophagic pathways and their implications for cancer development, progression, and resistance to therapy. MiRNAs, as critical regulators of gene expression post-transcription, influence various biological processes, including autophagy, a catabolic mechanism essential for cellular homeostasis, stress response, and survival. The review meticulously delineates the mechanisms through which miRNAs impact autophagy by targeting specific genes and signaling pathways, thereby affecting cancer cell proliferation, metastasis, and response to chemotherapy. It highlights several miRNAs with dual roles, acting either as oncogenes or tumor suppressors based on the cellular context and the specific autophagic pathways they regulate. The paper further explores the therapeutic potential of targeting miRNA-autophagy axis, offering insights into novel strategies for cancer treatment through modulation of this axis. Emphasizing the complexity of the miRNA-autophagy relationship, the review calls for more in-depth studies to unravel the nuanced regulatory networks between miRNAs and autophagy in cancer, which could pave the way for the development of innovative therapeutic interventions and diagnostic tools. [ABSTRACT FROM AUTHOR]

Amyotrophic lateral sclerosis (ALS) is a debilitating and fatal paralytic disorder associated with motor neuron death. Mutant superoxide dismutase 1 (SOD1) misfolding and aggregation have been linked to familial ALS, with the accumulation of abnormal wild-type SOD1 species being also observed in postmortem tissue of sporadic ALS cases. Both wild-type and mutated SOD1 are reported to contribute to motoneuron cell death. The autophagic pathway has been shown to be dysregulated in ALS. Recent evidence suggests a dual time-dependent role of autophagy in the progression of the disease. PACER, also called RUBCNL (Rubicon-like), is an enhancer of autophagy and has been found diminished in its levels during ALS pathology in mice and humans. Pacer loss of function disturbs the autophagy process and leads to the accumulation of SOD1 aggregates, as well as sensitizes neurons to death. Therefore, here we investigated if constitutive overexpression of PACER in neurons since early development is beneficial in an in vivo model of ALS. We generated a transgenic mouse model overexpressing human PACER in neurons, which then was crossbred with the mutant SOD1G93A ALS mouse model. Unexpectedly, PACER/SOD1G93A double transgenic mice exhibited an earlier disease onset and shorter lifespan than did littermate SOD1G93A mice. The overexpression of PACER in neurons in vivo and in vitro increased the accumulation of SOD1 aggregates, possibly due to impaired autophagy. These results suggest that similar to Pacer loss-of function, Pacer gain-of function is detrimental to autophagy, increases SOD1 aggregation and worsens ALS pathogenesis. In a wider context, our results indicate the requirement to maintain a fine balance of PACER protein levels to sustain proteostasis. [ABSTRACT FROM AUTHOR]

Background: Ferroptosis, a form of cell death characterized by lipid peroxidation, plays a crucial role in tumor suppression, offering novel avenues for cancer therapy. Previous studies have indicated that high levels of cyclin-dependent kinase subunit 2 (CKS2) promote the progression of various cancers. However, the potential interplay between CKS2 and ferroptosis in colon cancer (CC) remains unclear. Methods: Bioinformatics and RNA-seq analyses were employed to study genes associated with the ferroptosis signaling pathway. CKS2 expression was evaluated using quantitative reverse transcription polymerase chain reaction (qRT-PCR) and Western blot (WB). The in vitro and in vivo effects of CKS2 on CC cells were assessed through the CCK-8 assay, colony formation assay, propidium iodide (PI) staining, BODIPY staining, DCFH-DA staining, and animal experiments. Additionally, the impact of CKS2 on autophagy and glutathione (GSH) metabolism was investigated using a transmission electron microscope (TEM), immunofluorescence (IF) assays, WB experiments, and relevant assay kits. Results: CKS2 expression was elevated in CC, indicating a poor clinical outcome. Knockdown of CKS2 significantly enhanced Erastin-induced ferroptosis in CC cells, leading to reduced GSH metabolism. Conversely, CKS2 overexpression produced opposite effects. Mechanistically, CKS2-induced autophagy reinforced GSH metabolism, thereby increasing resistance to ferroptosis in CC cells. Furthermore, inhibiting CKS2 promoted tumor ferroptosis by downregulating GPX4 expression. Additionally, CKS2 knockdown effectively increased sorafenib-induced ferroptosis both in vitro and in vivo. Conclusion: CKS2 suppresses ferroptosis in CC by modulating GSH metabolism in both in vitro and in vivo settings. These findings offer new insights into targeting CKS2 for CC treatment and shed light on the mechanism of ferroptosis in CC. [ABSTRACT FROM AUTHOR]

BACKGROUND RESULTS CONCLUSION Epimedium polysaccharide (EPS) is a bioactive compound derived from the traditional Chinese herb Epimedium brevicornum. The objective of this study was to investigate the protective effects of EPS on ulcerative colitis (UC) and to elucidate the underlying mechanisms involved.The findings showed that EPS treatment mitigated UC symptoms, including weight loss, anal bleeding, elevated disease activity index (DAI), and colon shortening. Hematoxylin and eosin (H&E) and Alcian blue–periodic acid–Schiff (AB‐PAS) staining demonstrated that EPS alleviated histopathological damage and improved the integrity of the colonic mucosa. Mechanistically, EPS was found to substantially decrease inflammation by inhibiting the Toll‐like receptor 4/nuclear factor‐κB (TLR4/NF‐κB) signaling pathway and to alleviate oxidative stress through modulation of the Kelch‐like ECH‐associated protein 1/nuclear factor erythroid‐derived 2‐like 2 (Keap1/Nrf2) pathway. Notably, EPS failed to exert protective effects against dextran sulfate sodium (DSS)‐induced UC in Nrf2‐knockout (Nrf2−/−) mice. Additionally, Western blotting and immunohistochemical analysis demonstrated that EPS facilitated autophagy via the adenosine monophosphate‐dependent protein kinase/mammalian target of rapamycin (AMPK/mTOR) pathway. In vitro experiments revealed that EPS effectively suppressed lipopolysaccharide (LPS)‐mediated cellular damage and oxidative stress by regulating Keap1/Nrf2 pathway. Transcriptomic analysis of LPS‐treated Caco‐2 cells following EPS treatment revealed a significant up‐regulation of Nrf2 expression.In conclusion, the findings of this study suggest that EPS exerts protective effects against DSS‐induced UC through the inhibition of the TLR4/NF‐κB signaling pathway, regulation of the Keap1/Nrf2 pathway, and promotion of autophagy via the AMPK/mTOR pathway. Consequently, EPS may represent a potential therapeutic target for the treatment of UC. © 2024 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Although sarcopenia has been a serious public health concern worldwide in recent years, its effective prevention and intervention measures are still lacking. The latest research has found that autophagy dysfunction is an essential mechanism in the pathogenesis of sarcopenia. And meanwhile, increasing studies have shown that phytonutrients consumption is positively correlated with the maintenance of skeletal muscle mass and strength, which involves the regulation of the autophagy pathway. However, due to the opposite environmental-dependent effect of autophagy in sarcopenia, targeting autophagy by phytonutrients as the treatment of sarcopenia is sometimes considered controversial. Thus, in this review, based on the illustration of the relationship between autophagy and skeletal muscle and the complex changes of autophagy in sarcopenia, the phytonutrients ameliorating sarcopenia by regulating autophagy are reviewed with emphasis, and the possible underlying mechanisms are systematically summarized. Despite some controversies, most current studies support the idea that maintaining basal and functional autophagy contributes to the treatment of sarcopenia. Several phytonutrients exhibit substantial beneficial effects on sarcopenia by targeting autophagy, with polyphenols (especially catechins and urolithin A) considered to be of potentially effective clinical relevance. Hence, the development of phytonutrients is a promising approach to the treatment of sarcopenia and its complications. [ABSTRACT FROM AUTHOR]

Objectives: Endothelial-to-mesenchymal transition (EndoMT) is a significant biological phenomenon wherein endothelial cells undergo a loss of their endothelial traits and progressively acquire mesenchymal characteristics. Consequently, this transformation leads to both a compromised ability to maintain lumen permeability and alterations in vascular structure, which hampers the preservation of bloodbrain barrier integrity. This study aimed to investigate inflammation-induced EndoMT and its etiology, with the goal of impeding the infiltration of peripheral inflammation into the central nervous system. Materials and Methods: Lipolysaccharide (LPS) was administered intraperitoneally to mice several times to establish a chronic inflammatory model. A cellular inflammatory model was established by LPS in human brain microvascular endothelial cells (HBMECs). The mRNA expressions of inflammatory cytokines interleukin-1β (IL-1β) and IL-6 were detected by real-time polymerase chain reaction (PCR). Immunofluorescence staining of platelet endothelial cell adhesion molecule-1 (CD31) and alpha smooth muscle actin (α-SMA) was conducted to assess the level of EndoMT. The expression levels of Occludin, zona occludens protein 1 (ZO-1), Sestrin2, microtubule-associated protein1 light chain 3 (LC3) and inducible nitric oxide synthase (iNOS) were detected by western blotting. Results: LPS treatment induced the downregulation of ZO-1 and Occludin, which was accompanied by the elevated expressions of iNOS, α-SMA, Sestrin2 and LC3-II in the mouse cortex and HBMECs. Mechanistically, the knockdown of Sestrin2 in HBMECs exacerbated the EndoMT induced by LPS treatment, while the overexpression of Sestrin2 inhibited this process. Moreover, the induction of autophagy by rapamycin rescued the EndoMT induced by Sestrin2 knockdown. Conclusion: This study revealed that Sestrin2 inhibited endothelial inflammation and EndoMT via enhanced autophagy, which may provide a potential drug target for cerebrovascular inflammatory injury. [ABSTRACT FROM AUTHOR]

Hepatocellular carcinoma (HCC) is one of the most common malignances in the world, with high morbidity and mortality. Due to the hidden onset of symptoms, there are huge obstacles in early diagnosis, recurrence, metastasis and drug resistance. Although great strides have been made in the treatment of HCC, effective treatment options are still limited and achieving longer survival for patients remains urgent. Ferroptosis is a novel type of programmed cell death that is mainly caused by iron-dependent oxidative damage. With further investigations, ferroptosis has been proved to be associated with the occurrence and development of various tumors. This article reviews the regulatory mechanism and signal transduction pathways of ferroptosis, investigates the complex relationship between autophagy, sorafenib resistance and immunotherapy with ferroptosis involved in HCC, providing new ideas and directions for the treatment of HCC. [ABSTRACT FROM AUTHOR]

Objective: Mesenchymal stem cells (MSCs) have been highly confirmed for their critical role in the treatment of different diseases. This study focuses on the mechanism of umbilical cord–derived MSCs (UC‐MSCs) in the treatment of ornidazole (ORN)‐induced asthenozoospermia (AS) in rats via the AKT/mTOR pathway. Methods: An animal model of AS was established in ORN‐induced rats, followed by treatment of UC‐MSCs and rapamycin (autophagy activator) or MK‐2206 (AKT inhibitor). The sperm motility, concentration, and viability of rats were measured by an automatic sperm analyzer. Hematoxylin and eosin (HE) staining was conducted to observe the pathological injury of testicular tissue in rats. Terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay was utilized to evaluate the apoptosis rate of testicular cells. Western blot analysis was performed to determine the expression of apoptosis‐related proteins, autophagy‐related proteins, and AKT, p‐AKT, mTOR, and p‐mTOR. The rate of light chain 3 (LC3)–positive cells in testicular tissue was detected by immunohistochemistry (IHC). Results: In ORN‐induced AS rats, sperm motility, concentration, and viability as well as the number of mesenchymal cells and spermatogenic cells were significantly decreased, spermatogenic tubule space, apoptosis rate, and cleaved caspase‐3, LC3II/I, Beclin‐1, and LC3‐positive cell rates were increased, and Bcl2 was downregulated. UC‐MSCs could improve sperm quality and testicular injury in AS rats by inhibiting excessive autophagy. Besides, UC‐MSCs could activate the AKT/mTOR pathway. Moreover, inhibition of the AKT/mTOR pathway partially reversed the therapeutic effect of UC‐MSCs on ORN‐induced AS rats. Conclusion: UC‐MSCs inhibit autophagy and improve sperm quality in AS rats through the AKT/mTOR pathway, highlighting a new idea for the treatment of AS. [ABSTRACT FROM AUTHOR]

Phospholamban (PLN) plays a crucial role in regulating sarcoplasmic reticulum (SR) Ca2+ cycling and cardiac contractility. Mutations within the PLN gene have been detected in patients with cardiomyopathy, with the heterozygous variant c.40_42delAGA (p.R14del) of PLN being the most prevalent. Investigations into the mechanisms underlying the pathology of PLN-R14del have revealed that cardiac cells from affected patients exhibit pathological aggregates containing PLN. Herein, we performed comprehensive molecular and cellular analyses to delineate the molecular aberrations associated with the formation of these aggregates. We determined that PLN aggregates contain autophagic proteins, indicating inefficient degradation via the autophagy pathway. Our findings demonstrate that the expression of PLN-R14del results in diminished autophagic flux due to impaired fusion between autophagosomes and lysosomes. Mechanistically, this defect is linked to aberrant recruitment of key membrane fusion proteins to autophagosomes, which is mediated in part by changes in Ca2+ homeostasis. Collectively, these results highlight a novel function of PLN-R14del in regulating autophagy, that may contribute to the formation of pathogenic aggregates in patients with cardiomyopathy. Prospective strategies tailored to ameliorate impaired autophagy may hold promise against PLN-R14del disease. [ABSTRACT FROM AUTHOR]

Background: Glaucoma, characterized by a high incidence and significant ocular harm, has been elucidated through various mechanisms. Excessive autophagy leading to the loss of retinal ganglion cells (RGCs) is suggested as one potential cause for visual impairment in glaucoma. Methods: A glaucoma model was established through anterior chamber injection of silicone oil in mice. RTA408 and the positive control tafluprost were administered for intervention. The efficacy was preliminarily assessed by intraocular pressure measurement. HE staining and fluorescent staining were used to assess RGC loss, while fluorescent staining and western blot were employed to evaluate the expression of Nrf2. The role of autophagy in the pathogenesis of glaucoma was investigated by artificially modulating autophagy levels. Results: In glaucomatous mice, RTA408 significantly reduces the apoptosis levels of RGCs and decreases RGC loss. Further investigations reveal a notable upregulation of autophagy levels in glaucomatous mice, with RGC loss being associated with autophagy. RTA408 promotes the expression of Nrf2 and downstream antioxidant molecules, enhancing the antioxidant system while downregulating mitochondrial autophagy levels. This reduces RGC apoptosis and loss, demonstrating a protective effect against glaucoma. Conclusion: Autophagy mediates the occurrence of glaucoma in mice, promoting RGC apoptosis. RTA408 alleviates RGCs damage by inhibiting excessive autophagy in the context of glaucoma. [ABSTRACT FROM AUTHOR]

SUMMARY Peroxisomes house diverse metabolic pathways that are essential for plant and animal survival, including enzymes that produce or inactivate toxic byproducts. Despite the importance of peroxisomes and their collaborations with other organelles, the mechanisms that trigger or prevent peroxisome turnover and the cellular impacts of impaired peroxisomes are incompletely understood. When Arabidopsis thaliana LON2, a peroxisomal protein with chaperone and protease capacity, is disrupted, metabolic dysfunction and protein instability in peroxisomes ensue. Paradoxically, preventing autophagy in lon2 mutants appears to normalize peroxisomal metabolism and stabilize peroxisomal proteins—hinting at a role for autophagy in causing the peroxisomal defects observed in lon2 seedlings. Using a combination of transcriptomics, proteomics, and in silico investigations, we compared wild type to lon2 and autophagy null mutants and double mutants. Through this analysis, we found that impeding autophagy via an atg2 null mutation alleviated several of the global defects observed when LON2 is absent. Moreover, we revealed processes influenced by LON2 that are independent of autophagy, including impacts on lipid droplet and chloroplast protein levels. Finally, we identified and classified potential LON2 substrates, which include proteins that might provide signal(s) for pexophagy. [ABSTRACT FROM AUTHOR]

Sodium-glucose cotransporter 2 (SGLT2) inhibitors exert a distinctive pattern of direct biological effects on the heart and kidney under experimental conditions, but the meaningfulness of these signatures for patients with heart failure has not been fully defined. We performed the first mechanistic validation study of large-scale proteomics in a double-blind randomized trial of any treatment in patients with heart failure. In a discovery cohort from the EMPEROR (Empagliflozin Outcome Trial in Patients With Chronic Heart Failure and Reduced Ejection Fraction) program, we studied the effect of randomized treatment with placebo or empagliflozin on 1,283 circulating proteins in 1,134 patients with heart failure with a reduced or preserved ejection fraction. In a validation cohort, we expanded the number to 2,155 assessed proteins, which were measured in 1,120 EMPEROR participants who had not been studied previously. In the validation cohort, 25 proteins were the most differentially enriched by empagliflozin (ie, ≥15% between-group difference and false discovery rate <1% at 12 weeks with known effects on the heart or kidney): 1) 13 proteins promote autophagy and other cellular quality-control functions (IGFBP1, OTUB1, DNAJB1, DNAJC9, RBP2, IST1, HSPA8, H-FABP, FABP6, ATPIFI, TfR1, EPO, IGBP1); 2) 12 proteins enhance mitochondrial health and ATP production (UMtCK, TBCA, L-FABP, H-FABP, FABP5, FABP6, RBP2, IST1, HSPA8, ATPIFI, TfR1, EPO); 3) 7 proteins augment cellular iron mobilization or erythropoiesis (TfR1, EPO, IGBP1, ERMAP, UROD, ATPIF1, SNCA); 4) 3 proteins influence renal tubular sodium handling; and 5) 9 proteins have restorative effects in the heart or kidneys, with many proteins exerting effects in >1 domain. These biological signatures replicated those observed in our discovery cohort. When the threshold for a meaningful between-group difference was lowered to ≥10%, there were 58 additional differentially enriched proteins with actions on the heart and kidney, but the biological signatures remained the same. The replication of mechanistic signatures across discovery and validation cohorts closely aligns with the experimental effects of SGLT2 inhibitors. Thus, the actions of SGLT2 inhibitors—to promote autophagy, restore mitochondrial health and production of ATP, promote iron mobilization and erythropoiesis, influence renal tubular ion reabsorption, and normalize cardiac and renal structure and function—are likely to be relevant to patients with heart failure. (EMPagliflozin outcomE tRial in Patients With chrOnic heaRt Failure With Preserved Ejection Fraction [EMPEROR-Preserved], NCT03057951 ; EMPagliflozin outcomE tRial in Patients With chrOnic heaRt Failure With Reduced Ejection Fraction [EMPEROR-Reduced], NCT03057977) [ABSTRACT FROM AUTHOR]

Purpose: Breast cancer is a common malignancy in women, and its metastasis is a leading cause of cancer-related deaths. Single-cell RNA sequencing (scRNA-seq) can distinguish the molecular characteristics of metastasis and identify predictor genes for patient prognosis. This article explores gene expression in primary breast cancer tumor tissue against metastatic cells in the lymph node and liver using scRNA-seq. Methods: Breast cancer scRNA-seq data from the Gene Expression Omnibus were used. The data were processed using R and the Seurat package. The cells were clustered and identified using Metascape. InferCNV is used to analyze the variation in copy number. Differential expression analysis was conducted for the cancer cells using Seurat and was enriched using Metascape. Results: We identified 18 distinct cell clusters, 6 of which were epithelial. CNV analysis identified significant alterations with duplication of chromosomes 1, 8, and 19. Differential gene analysis resulted in 17 upregulated and 171 downregulated genes for the primary tumor in the primary tumor vs. liver metastasis comparison and 43 upregulated and 4 downregulated genes in the primary tumor in the primary tumor vs lymph node metastasis comparison. Several enriched terms include Ribosome biogenesis, NTP synthesis, Epithelial dedifferentiation, Autophagy, and genes associated with epithelial-to-mesenchymal transitions. Conclusion: No single gene or pathway can clearly explain the mechanisms behind tumor metastasis. Several mechanisms contribute to lymph node and liver metastasis, such as the loss of differentiation, epithelial-to-mesenchymal transition, and autophagy. These findings necessitate further study of metastatic tissue for effective drug development. [ABSTRACT FROM AUTHOR]

Astrocytes are the most abundant cells in the brain and show neuroprotective function in CNS and reactive astrocytes are characteristic in neurodegenerative diseases. The JAK2-STAT3 pathway plays a crucial role in the process of astrocyte activation. However, as a hallmark of Parkinson's disease, the change in α-syn under the influence of STAT3 inhibitor and the underlying cellular mechanisms remain elusive. Here, we show that PFF can induce an increase in α-syn in SVG p12 cells, which is further enhanced after the inhibition of STAT3. The underlying mechanisms involve the downregulation of autophagy levels and a concurrent decrease in lysosomal function after inhibition of STAT3. Additionally, we observed inhibition of STAT3 resulted in reduced exosome secretion in SVG p12 cells. This is attributed to alterations in SNARE, leading to impaired fusion between MVBs and the cell membrane, subsequently causing the accumulation of intracellular MVBs. Taken together, our data demonstrates that inhibition of STAT3 decreases both the autophagy and lysosome function, which may increase MVBs production. However, we found a potentially decreased exosome production that may be implicated with SNARE complex and need further exploration. [ABSTRACT FROM AUTHOR]

Background: The mitochondrial dysfunction and oxidative stress imbalance caused by macrophage polarization play a role in the progression of COPD, with CDGSH iron–sulfur domain-containing protein 1 (CISD1) playing a key role. This study revealed the role and mechanism of CISD1 in smoke-induced macrophages. Methods: Using a pure cigarette smoke exposure-induced COPD mouse model, stimulation of Raw264.7 macrophages with cigarette smoke extract mimics the COPD environment. Knocking down CISD1 expression in macrophages and combining it with high-throughput sequencing to obtain subsequent differentially expressed genes and pathways. Macrophage polarization tendency under different treatments was determined using flow cytometry. Meanwhile, Mitosox, JC-1, DCFH-DA fluorescence intensity was measured to detect mitochondrial function and cellular oxidative stress levels. Western Blot technique was employed to validate autophagy (mitochondrial autophagy) pathway-related proteins. In addition, Elisa technique was used to measure inflammatory factors (IL-6, TNF-a) in the cell supernatant after co-culturing macrophages (Raw264.7) with epithelial cells (MLE12). Results: CISD1 is underexpressed in peripheral blood monocytes of COPD patients. Under in vitro conditions, we verified that cigarette smoke (smoke extract) indeed inhibits CISD1 expression in macrophages. Subsequently, we found that macrophages with knocked-down CISD1 tend to polarize towards M1 phenotype, and exhibit signs of mitochondrial dysfunction and oxidative stress imbalance. In addition, we observed significant activation of the autophagy pathway in CISD1-inhibited macrophages, with upregulation of LC3A/B and downregulation of p62 protein, as well as increased expression of mitochondrial autophagy-related proteins (PINK1, PARKN). Furthermore, co-culturing CISD1-knockdown macrophages (Raw264.7) with epithelial cells (MLE12) resulted in upregulation of inflammatory factors in the supernatant. Conclusions: Smoke-induced reduction of CISD1 in macrophages promotes M1 polarization and mitochondrial dysfunction by activating the autophagy pathway, thereby promoting the occurrence and development of COPD. [ABSTRACT FROM AUTHOR]

Loss-of-function mutations in MECP2 are associated to Rett syndrome (RTT), a severe neurodevelopmental disease. Mainly working as a transcriptional regulator, MeCP2 absence leads to gene expression perturbations resulting in deficits of synaptic function and neuronal activity. In addition, RTT patients and mouse models suffer from a complex metabolic syndrome, suggesting that related cellular pathways might contribute to neuropathogenesis. Along this line, autophagy is critical in sustaining developing neuron homeostasis by breaking down dysfunctional proteins, lipids, and organelles. Here, we investigated the autophagic pathway in RTT and found reduced content of autophagic vacuoles in Mecp2 knock-out neurons. This correlates with defective lipidation of LC3B, probably caused by a deficiency of the autophagic membrane lipid phosphatidylethanolamine. The administration of the autophagy inducer trehalose recovers LC3B lipidation, autophagosomes content in knock-out neurons, and ameliorates their morphology, neuronal activity and synaptic ultrastructure. Moreover, we provide evidence for attenuation of motor and exploratory impairment in Mecp2 knock-out mice upon trehalose administration. Overall, our findings open new perspectives for neurodevelopmental disorders therapies based on the concept of autophagy modulation. Synopsis: Autophagosome biogenesis is impaired in Rett syndrome, a complex neurodevelopmental disorder caused by loss of function mutations in MECP2. Autophagy enhancement restores defects in neurons lacking Mecp2, suggesting a possible contribution of this pathway in the pathogenesis of Rett. LC3B-II lipidation, which is essential for autophagosome biogenesis, is defective in Mecp2 KO cells, probably due to the reduced availability of phosphatidylethanolamine (PE). The natural disaccharide and autophagy inducer trehalose restores the amount of PE and improves dendritic complexity and synaptic ultrastructure in Mecp2 KO neurons. In vivo administration of trehalose ameliorates exploratory and locomotor skills of Mecp2 KO male mice. Autophagosome biogenesis is impaired in Rett syndrome, a complex neurodevelopmental disorder caused by loss of function mutations in MECP2. Autophagy enhancement restores defects in neurons lacking Mecp2, suggesting a possible contribution of this pathway in the pathogenesis of Rett. [ABSTRACT FROM AUTHOR]

Parkinson's disease (PD) is the second neurodegenerative disorder most prevalent in the world, characterized by the loss of dopaminergic neurons in the Substantia Nigra (SN). It is well known for its motor and non-motor symptoms including bradykinesia, resting tremor, psychiatric, cardiorespiratory, and other dysfunctions. Pathological apoptosis contributes to a wide variety of diseases including PD. Various insults and/or cellular phenotypes have been shown to trigger distinct signaling events leading to cell death in neurons affected by PD. The intrinsic or mitochondrial pathway, inflammatory or oxidative stress-induced extrinsic pathways are the main events associated with apoptosis in PD-related neuronal loss. Although SN is the main brain area studied so far, other brain nuclei are also affected by the disease leading to non-classical motor symptoms as well as non-motor symptoms. Among these, the respiratory symptoms are often overlooked, yet they can cause discomfort and may contribute to patients shortened lifespan after disease diagnosis. While animal and in vitro models are frequently used to investigate the mechanisms involved in the pathogenesis of PD in both the SN and other brain regions, these models provide only a limited understanding of the disease's actual progression. This review offers a comprehensive overview of some of the most studied forms of cell death, including recent research on potential treatment targets for these pathways. It highlights key findings and milestones in the field, shedding light on the potential role of understanding cell death in the prevention and treatment of the PD. Therefore, unraveling the connection between these pathways and the notable pathological mechanisms observed during PD progression could enhance our comprehension of the disease's origin and provide valuable insights into potential molecular targets for the developing therapeutic interventions. [ABSTRACT FROM AUTHOR]

Lung disease development involves multiple cellular processes, including inflammation, cell death, and proliferation. Research increasingly indicates that autophagy and its regulatory proteins can influence inflammation, programmed cell death, cell proliferation, and innate immune responses. Autophagy plays a vital role in the maintenance of homeostasis and the adaptation of eukaryotic cells to stress by enabling the chelation, transport, and degradation of subcellular components, including proteins and organelles. This process is essential for sustaining cellular balance and ensuring the health of the mitochondrial population. Recent studies have begun to explore the connection between autophagy and the development of different lung diseases. This article reviews the latest findings on the molecular regulatory mechanisms of autophagy in lung diseases, with an emphasis on potential targeted therapies for autophagy. [ABSTRACT FROM AUTHOR]

Signal transducer and activator of transcription 1 (STAT1) plays a critical role in immune response, human STAT1 as a transcriptional suppressor of autophagy genes and autophagic activity. Classical swine fever virus (CSFV)-infected induce autophagy, leading to immune evasion. However, there are limited reports on the function of porcine STAT1 in autophagy during CSFV infection. There is also lack of suitable in vitro models for studying porcine STAT1. The objective of this study was to establish porcine PK-15 STAT1-/- and 3D4/21 STAT1-/- cell lines using the CRISPR/Cas9 system to investigate the function of the STAT1 in autophagy. The PK-15STAT1-/- and 3D4/21STAT1-/- cell lines, featuring homozygous knockout of STAT1 gene were successfully constructed using the CRISPR/Cas9 editing system. The knockout efficiency determined to be 82.4% and 81.1%, respectively. Infection with CSFV in porcine PK-15STAT1-/- and 3D4/21STAT1-/- cells led to an observable increase in autophagosomes as evidenced by transmission electron microscope. Additionally, STAT1 knockout (STAT1-/-) by the CRISPR/Cas9 system upregulated the expression of ULK1, Beclin1, and LC3 genes, thereby enhancing autophagy during CSFV infection. Conversely, overexpression of STAT1 downregulated the expression of ULK1, Beclin1, and LC3 genes, leading to inhibition of autophagy during CSFV infection.The application of an autophagy dual-fluorescent-tracking plasmid demonstrated that STAT1 knockout enhanced autophagy accumulation during CSFV infection, while STAT1 overexpression inhibited it. Moreover, the 3D4/21STAT1-/- cell line proved to be a more suitable in vitro model compared to the PK-15STAT1-/- cell line for elucidating the involvement of STAT1 in autophagy during CSFV infection. [ABSTRACT FROM AUTHOR]

In neurodegenerative diseases, the activation of microglia and the ensuing neuroinflammation are pivotal in regulating disease progression. Attenuating inflammation induced by microglial cells is considered a key strategy for slowing the progression of neurodegenerative diseases. γ‐glutamylcysteine (γ‐GC) has exhibited significant antioxidative and anti‐inflammatory effects; nevertheless, its potential role in modulating neuroinflammatory responses remains incompletely explored. The current investigation aimed to establish a neuroinflammation model by stimulating BV2 microglia cells with lipopolysaccharide (LPS) and to explore the protective effect of γ‐GC on neuroinflammation in BV2 microglia cells. The results demonstrated that γ‐GC significantly attenuated LPS‐induced oxidative damage in BV2 cells, reduced the levels of tumor necrosis factor‐α (TNF‐α) and interleukin‐1β (IL‐1β), inhibited the cytoplasmic translocation of high‐mobility group box 1 protein (HMGB1), and effectively mitigated the LPS‐induced inflammatory response in BV2 cells. We further investigated the regulatory mechanism of γ‐GC on LPS‐induced BV2 neuroinflammation and found that γ‐GC significantly enhances autophagy in BV2 cells, resulting in a marked reduction in mammalian target of rapamycin (mTOR) phosphorylation levels and an increase in AMP‐activated protein kinase (AMPK) phosphorylation levels. The use of autophagy inhibitors 3‐methyladenine (3‐MA) and AMPK inhibitors further corroborates the proposition that γ‐GC promotes autophagy in BV2 cells while suppressing the LPS‐induced inflammatory response of BV2 microglia through the activation of the AMPK‐mTOR pathway. The findings indicate that γ‐GC exerts a substantial inhibitory impact on neuroinflammation, making it a promising candidate for the development of therapeutic strategies against neuroinflammatory disorders and related conditions. [ABSTRACT FROM AUTHOR]

Cisplatin (CDDP) serves as a vital component in the chemotherapeutic approach to treat esophageal squamous cell carcinoma (ESCC). However, prolonged CDDP application frequently culminates in resistance, compromising therapeutic outcomes. Through genome-wide CRISPR library screening, our study elucidates the mechanisms underlying this resistance, pinpointing CYFIP2 as a pivotal mediator. Notably, the involvement CYFIP2 is characterized by pronounced autophagic activity and the modulation of multiple cellular pathways. Empirical validation was achieved by treating ESCC cell lines with CDDP, which resulted in an upsurge of CYFIP2 expression. The functional impact of CYFIP2 was further delineated through knockdown experiments, where a marked suppression in cell proliferation was observed, alongside a discernible decline in reactive oxygen species levels. This was complemented by a suite of assays and microscopic techniques, including GFP-LC3, mRFP-GFP-LC3, electron microscopy and western blot, which collectively affirmed the inhibitory effect of CYFIP2 knockdown on autophagic processes, particularly impeding autophagosome formation and their subsequent fusion with lysosomes. In vivo studies have also confirmed that CYFIP2 knockdown limits tumor progression and increases CDDP efficacy. Conclusively, our findings introduce CYFIP2 as a novel contributor to CDDP resistance in ESCC, underscoring its potential as a therapeutic target. This revelation not only deepens our understanding of resistance mechanisms but also paves the way for novel oncotherapeutic strategies, promising enhanced treatment efficacy against ESCC. [ABSTRACT FROM AUTHOR]

Intestinal ischemia/reperfusion injury (I/R) is a common yet challenging-to-treat condition, presenting a significant clinical challenge. This study aims to investigate the protective mechanisms of Dexmedetomidine (Dex) against I/R injury, with a particular focus on its role in regulating autophagy activity in intestinal neurons and maintaining mitochondrial homeostasis. Experimental findings demonstrate that Dex can mitigate intestinal damage induced by I/R through the modulation of autophagy activity and mitochondrial function in intestinal neurons by suppressing the expression of Nupr1. This discovery sheds light on a new molecular mechanism underlying the potential efficacy of Dex in treating intestinal I/R injury, offering valuable insights for clinical therapy. [ABSTRACT FROM AUTHOR]

Background: Hepatitis B virus (HBV) is an enveloped DNA virus that causes chronic hepatitis B (CHB) infection. Annexin, a Ca2+-activated protein, is widely expressed in various organs and tissues and has potential utility in disease diagnosis and treatment. However, the relationship between the annexin family and CHB remains unclear. Methods: Clinical samples from hepatitis patients and donors or healthy individuals were collected. Transcriptome sequencing in CHB liver tissues and HBV-infected cells were performed. HepG2.2.15 cells with the full-length HBV genome and HBV-infected HepG2-NTCP cell models were established. HBV-infected mouse model was constructed and adeno-associated virus was utilized. Results: ANXA4 expression was elevated during CHB infection. ANXA4 knockdown promoted HBV replication and aggravated liver injury, while ANXA4 overexpression alleviated that. Mechanistically, autophagy pathway was activated by ANXA4 deficiency, promoting autophagic degradation of minichromosome maintenance complex component 2 (MCM2). MCM2 inhibition activated HBV replication, while MCM2 overexpression attenuated ANXA4 deficiency-induced HBV replication and liver injury. Clinically, the expression of hepatitis B viral protein was negatively correlated with the ANXA4 levels, and CHB patients with high ANXA4 levels (> 8 ng/ml) showed higher sensitivity to interferon therapy. Conclusions: ANXA4 functions as a protective factor during HBV infection. ANXA4 expression is elevated under HBV attack to restrict HBV replication by inhibiting autophagic degradation of MCM2, thereby alleviating liver injury and suppressing the CHB infection process. ANXA4 also enhances the sensitivity of CHB patients to interferon therapy. Therefore, ANXA4 is expected to be a new target for CHB treatment and prognostic evaluation. Highlights: • ANXA4 expression is elevated during CHB infection in both patients and mice. • ANXA4 knockdown promotes HBV replication and transcription and aggravates liver injury. • Autophagy is activated when ANXA4 deficiency, promoting autophagic degradation of MCM2. • Inhibition of MCM2 expression activates HBV replication directly, while MCM2 overexpression attenuates ANXA4 deficiency-induced HBV replication and liver injury. • The expression of hepatitis B viral protein is negatively correlated with the ANXA4 levels, and ANXA4 enhances the sensitivity of CHB patients to interferon therapy. [ABSTRACT FROM AUTHOR]

Compounds that can induce oxidative stress in cancer cells while remaining nontoxic to healthy cells are extremely promising for potential anticancer drugs. 2,2′:6′,2′′-terpyridine-metal complexes possess these properties. The high level of activity (IC50 = 0.605 µM) of 2,2′:6′,2′′-terpyridine-metal complexes on lung, breast, pancreatic, and glioblastoma multiforme cancer lines and their selectivity (SI > 41.32) on human normal fibroblasts were confirmed and presented in this paper. The mechanism of action of these compounds is associated with the generation of reactive oxygen species, which affects several cellular pathways and signals. The results demonstrate that 2,2′:6′,2′′-terpyridine-metal complexes affect cell cycle inhibition in the G0/G1 phase as well as the activation of apoptosis and autophagy cell death. These results were confirmed in several independent studies, including experiments measuring the fluorescence levels of reactive oxygen species, flow cytometry, and gene and protein analysis. [ABSTRACT FROM AUTHOR]

Autophagy is a mechanism for the degradation of cellular components in eukaryotes and plays a critical role in plant responses to abiotic stress. As a core member of the autophagy process, ATG8's role in how plants respond to heat stress remains unclear. To investigate the response of the tomato autophagy core member ATG8f to heat stress, we studied the key gene ATG8f and generated tomato lines overexpressing SlATG8f using the recombinant expression vector pBWA(V)HS. We observed that under heat stress, SlATG8f overexpression (OE) plants exhibited decreased heat tolerance compared to wild-type (WT) plants. Specifically, OE plants showed increased relative electrolyte leakage, reduced soluble solid content, elevated chlorophyll content, and higher autophagosome numbers, with less damage to chloroplasts and mitochondria. Additionally, expression of some ATG8 family genes and heat shock protein-related genes was upregulated. Moreover, SlATG8f overexpressing plants had higher pollen vitality and more intact pollen morphology. These results suggest that while SlATG8f overexpression renders plants more sensitive to heat, it helps mitigate high-temperature damage to tomato pollen by maintaining chloroplast integrity and interacting with heat shock proteins to respond to heat stress. [ABSTRACT FROM AUTHOR]

Asynchronous nuclear and cytoplasmic maturation in human oocytes is believed to cause morphological anomalies after controlled ovarian hyperstimulation. Vacuolar protein sorting 34 (VPS34) is renowned for its pivotal role in regulating autophagy and endocytic trafficking. To investigate its impact on oocyte development, oocyte‐specific knockout mice (ZcKO) are generated, and these mice are completely found infertile, with embryonic development halted at 2‐ to 4‐cell stage. This infertility is related with a disruption on autophagic/mitophagic flux in ZcKO oocytes, leading to subsequent failure of zygotic genome activation (ZGA) in derived 2‐cell embryos. The findings further elucidated the regulation of VPS34 on the activity and subcellular translocation of RAS‐related GTP‐binding protein 7 (RAB7), which is critical not only for the maturation of late endosomes and lysosomes, but also for initiating mitophagy via retrograde trafficking. VPS34 binds directly with RAB7 and facilitates its activity conversion through TBC1 domain family member 5 (TBC1D5). Consistent with the cytoplasmic vacuolation observed in ZcKO oocytes, defects in multiple vesicle trafficking systems are also identified in vacuolated human oocytes. Furthermore, activating VPS34 with corynoxin B (CB) treatment improved oocyte quality in aged mice. Hence, VPS34 activation may represent a novel approach to enhance oocyte quality in human artificial reproduction. [ABSTRACT FROM AUTHOR]

The intracellular distribution and transportation process are essential for maintaining PD‐L1 (programmed death‐ligand 1) expression, and intervening in this cellular process may provide promising therapeutic strategies. Here, through a cell‐based high content screening, it is found that the ABCB1 (ATP binding cassette subfamily B member 1) modulator zosuquidar dramatically suppresses PD‐L1 expression by triggering its autophagic degradation. Mechanistically, ABCB1 interacts with PD‐L1 and impairs COP II‐mediated PD‐L1 transport from ER (endoplasmic reticulum) to Golgi apparatus. The treatment of zosuquidar enhances ABCB1‐PD‐L1 interaction and leads the ER retention of PD‐L1, which is subsequently degraded in the SQSTM1‐dependent selective autophagy pathway. In CT26 mouse model and a humanized xenograft mouse model, zosuquidar significantly suppresses tumor growth and accompanies by increased infiltration of cytotoxic T cells. In summary, this study indicates that ABCB1 serves as a negative regulator of PD‐L1, and zosuquidar may act as a potential immunotherapy agent by triggering PD‐L1 degradation in the early secretory pathway. [ABSTRACT FROM AUTHOR]