Autophagy最新文献

The lysosome is not only a degradative organelle but also an essential platform for signal transduction, such as with MTOR signaling. The reciprocal regulation between the lysosome and MTOR is central to macroautophagy/autophagy and metabolism. MTOR-mediated suppression of lysosomal acidification is important for lysosomal activity, autophagic flux, and cell survival. VASN is a transmembrane glycoprotein whose function is not fully understood. In the present study, we report that VASN is a TGFB-inducible protein and plays a crucial role in positively regulating lysosomal acidification. As a potential mechanism, we demonstrated that VASN localizes to the lysosome, interacts with lysosomal MTOR and STK11IP, and disrupts the binding of STK11IP to MTOR and the V-ATPase, which was recently reported to suppress lysosomal acidification. We found that VASN's function in modulating lysosomal activity is essential for optimal mitophagy induced by TGFB and terminal erythroid differentiation and is critical for the progression of mutant KRAS-driven lung cancer. Overall, our study identified VASN as a novel TGFB-inducible regulator of lysosomal function.Abbreviations: ATG5, autophagy related 5; BNIP3, BCL2 interacting protein 3; BNIP3L, BCL2 interacting protein 3 like; CLEM, correlative-light electron microscopy; DSP, dithiobis(succinimidyl propionate); EGFP, enhanced green fluorescent protein; EYFP, enhanced yellow fluorescent protein; FIB-SEM, focused ion beam-scanning electron microscopy; LAMP1, lysosomal-associated membrane protein 1; LysoIP, lysosomal immunoprecipitation; MAP1LC3B, microtubule-associated protein 1 light chain 3 beta; MTOR, mechanistic target of rapamycin kinase; RBCs, red blood cells; SMAD, SMAD family member; STK11IP, serine/threonine kinase 11 interacting protein; TEM, transmission electron microscopy; TGFB, transforming growth factor beta; TGOLN2/TGN38, trans-golgi network protein 2; TMEM192, transmembrane protein 192; V-ATPase, vacuolar-type H⁺-translocating ATPase.

Clinicians typically avoid antibiotics use during immunotherapy due to concerns about reduced efficacy. However, cancer patients requiring antibiotics postoperatively or for infections urgently need options that provide antimicrobial coverage while potentially enhancing, rather than impairing, immunotherapy. Restoring ferroptosis susceptibility represents a promising strategy to overcome immunotherapy resistance, yet the role of antibiotics in modulating ferroptosis and interacting with immunotherapy remains unexplored. In this study, we screened 96 FDA-approved antibiotics across seven pharmacological classes and identified the macrolide kitasamycin as a specific and potent ferroptosis sensitizer in vitro and in vivo. Mechanistically, kitasamycin competitively bound to HUWE1, inhibiting its E3 ubiquitin ligase activity, which stabilized NCOA4 and activated the NCOA4-FTH1 ferritinophagy axis. Single-cell transcriptomics, flow cytometry, and multiplex immunohistochemistry revealed that kitasamycin induced immunogenic ferroptosis and reshaped anti-tumor T-cell immunity. Critically, kitasamycin potentiated immune checkpoint blockade (ICB)-mediated ferroptosis and overcame ICB resistance across multiple preclinical melanoma models, including B16F10 subcutaneous tumors, BRAF-PTEN-driven spontaneous tumors, and human sourced peripheral blood mononuclear cells (HsPBMCs)-humanized mouse models. Clinically, a high NCOA4, low HUWE1 signature correlated with ferroptosis activation, increased T-cell infiltration, and improved survival in ICB-treated patients, suggesting its potential as a predictive biomarker. Our findings positioned kitasamycin as a promising adjunct to immunotherapy for cancer patients requiring concurrent antibiotic therapy.Abbreviations: FTH1: ferritin heavy chain 1; ICB: immune checkpoint blockade; IFNG: interferon gamma; mIHC: multiplex immunohistochemistry; scRNA-seq: single-cell RNA sequencing.

Mitochondria serve as the cellular "power plants," supplying energy and regulating metabolism, signal transduction, and other physiological processes. To successfully replicate within host cells, viruses have evolved multiple strategies to hijack mitochondrial functions. The oncolytic Newcastle disease virus (NDV) causes severe organelle damage in tumor cells; however, how it manipulates mitochondrial architecture to facilitate its own replication remains poorly understood. Here, we provide evidence that NDV infection disrupts mitochondrial spatial distribution and imbalances mitochondrial fusion and fission, leading to mitochondrial structural damage. The resulting accumulation of fragmented mitochondria is cleared via PRKN-dependent mitophagy, a process that supports NDV replication. Interestingly, although MAVS (mitochondrial antiviral signaling protein) is degraded along with mitophagy, genetic ablation of PRKN - while blocking MAVS degradation - does not restore downstream innate immune responses. This indicates that NDV exploits mitophagy to enhance replication through mechanisms not entirely dependent on the suppression of MAVS-mediated immunity. Given the central role of mitochondria, we further explored the link between amino acid metabolism and viral proliferation after NDV infection. Our results show that NDV-induced mitophagy leads to the accumulation of free amino acids in host cells, and this metabolic reprogramming promotes viral replication. In summary, we show that NDV drives its replication by remodeling mitochondrial dynamics to induce mitophagy, which in turn triggers an amino acid metabolic reprogramming that benefits the virus. This provides new insights into the mechanisms supporting efficient oncolytic NDV replication, offering potential avenues for therapeutic intervention in oncolytic virus therapy.Abbreviations: CCCP: carbonyl cyanide m-chlorophenylhydrazone; COX4/COX IV: cytochrome c oxidase subunit 4; CQ: chloroquine; DENV: dengue virus; DNM1L/DRP1: dynamin 1 lik;ETC: electron transport chain; FIS1: fission, mitochondrial 1; HBV: hepatitis B virus; IAV: influenza A virus; IMM: inner mitochondrial membrane; JEV: japanese encephalitis virus; MAVS: mitochondrial antiviral signaling protein; MFF: mitochondrial fission factor; MFN1: mitofusin 1; MFN2: mitofusin 2; MOI: multiplicity of infection; MV: measles virus; NDV: Newcastle disease virus; OMM: outer mitochondrial membrane; OPA1: OPA1 mitochondrial dynamin like GTPase; PINK1: PTEN induced kinase 1; PRKN/parkin: parkin RBR E3 ubiquitin protein ligase; RLR: RIG-I-like receptor; SDHA: succinate dehydrogenase complex flavoprotein subunit A; TCA: tricarboxylic acid cycle; TCID₅₀: tissue culture infective doses; TEM: transmission electron microscopy; TIMM23: translocase of inner mitochondrial membrane 23; TOMM20: translocase of outer mitochondrial membrane 20.

Bone is an attractive site for cancer colonization, both for primary tumors such as osteosarcoma and for metastases of various malignancies. Preventing bone metastasis, which is associated with a poor prognosis, is a major challenge and identifying the factors involved in skeletal tumoral development is crucial to improve survival. In the present work, we showed that inactivation of the macroautophagy/autophagy-essential gene Atg5 in osteoblasts, the cells in charge of bone formation, stimulates osteosarcoma and breastbone metastasis growth as well as metastatic dissemination. We determined that Atg5 inactivation leads to systemic inflammation and bone proteome modifications including translation downregulation, stress granule formation, and upregulation of fatty acid beta-oxidation. In addition, Atg5 inactivation triggered lysosomal exocytosis through an autophagy-independent effect. Thus, our findings indicated that autophagy/ATG5 deficiency in the bone microenvironment generates a favorable environment for tumor development through several mechanisms and suggested that a bone-targeted autophagy inducer could be used to delay bone metastasis appearance.Abbreviations: ACP5/TRAP : acid phosphatase 5, tartrate resistant; CHI3L1 : chitinase 3 like 1; COL1A1 : collagen type I alpha 1 chain; ECM: extracellular matrix ; FDR: false discovery rate; G3BP1 : G3BP stress granule assembly factor 1; GSEA : gene set enrichment analyses; IFNG : interferon gamma; IL1B : interleukin 1 beta; IL23A : interleukin 23; IPA: ingenuity pathway analyses; ITGAX/CD11c : integrin subunit alpha X; KO : knockout; LAMP1 : lysosomal associated membrane protein 1; LGALS3 : galectin 3; LLOMe : L-leucyl-L-leucine methyl ester; OB : osteoblast; OC : osteoclast; PDCD6IP/Alix : programmed cell death 6 interacting protein; PDK4 : pyruvate dehydrogenase kinase 4.

Mitochondria regulate ATP production, calcium buffering, and apoptotic signaling, and clearing dysfunctional mitochondria by mitophagy is essential for cellular homeostasis. While PINK1-dependent mitophagy is well-characterized in neurons, its function in glial cells such as astrocytes is less understood. Our study demonstrates that PINK1-mitophagy in astrocytes occurs faster and with less spatial restriction compared to neurons. This pathway was specifically regulated in astrocytes by the glycolytic enzyme, HK2 (hexokinase 2), which forms a glucose-dependent complex with PINK1 following mitochondrial damage. Inflammation also induces HK2-PINK1 mitophagy, and its activation in astrocytes protects against cytokine-induced neuronal death. Our findings characterize a novel HK2-PINK1 pathway in astrocytes that bridges mitophagy, metabolism, and immune signaling.Abbreviation: HK2: hexokinase 2; PD: Parkinson disease; PINK1: PTEN induced kinase 1; S65: serine 65.

Mitochondrial damage in fibroblast-like synoviocytes (FLSs) is a key factor involved in the development and progression of rheumatoid arthritis (RA). In this study, we investigated the role of mitochondrial dysfunction of FLSs in the pathogenesis of RA. We induced inflammation by stimulating FLSs with TNF and IL17. Then, we transplanted fresh mitochondria into stimulated FLSs and evaluated the mitochondrial and lysosomal functions, macroautophagic/autophagic activity, and the STING1-associated cell death pathway. Next, we transplanted mitochondria or gold nanoparticle-conjugated mitochondria (GNP-Mito) into collagen-induced arthritis (CIA) mice and evaluated their therapeutic effects in vivo. Mitochondrial and lysosomal activities were decreased and autophagosomes accumulated in the stimulated FLSs. Furthermore, the STING1 signaling pathway and STING1-associated cell death were increased in the inflammatory condition. Mitochondrial transplantation into stimulated FLSs enhanced the mitochondrial and lysosomal activities and activated the autophagic activity, as demonstrated by decreased numbers of autophagosomes and increased numbers of autolysosomes. Mitochondrial transplantation decreased and increased the T_h17 and T_reg populations, respectively. Mitochondrial function and autophagic activity were enhanced by mitochondrial transplantation. Taken together, our results demonstrate that mitochondrial dysfunction in FLSs plays a pivotal role in the pathophysiology of RA and mitochondrial transplantation has therapeutic potential for RA development and progression.Abbreviations: ATP:adenosine triphosphate; CGAS: cyclic GMP-AMP synthase; CIA:collagen-induced arthritis; FLS: fibroblast-like synoviocytes; GNP:gold nanoparticle; ROS: reactive oxygen species; SQSTM1/p62:sequestosome 1; STING1: stimulator of interferon response cGAMPinteractor 1; MAP1LC3B/LC3B: microtubule associated protein 1 lightchain 3 beta.

Golgi fragmentation is a prominent early hallmark of neurodegenerative diseases such as Alzheimer disease (AD) and amyotrophic lateral sclerosis (ALS), yet the shared molecular mechanisms underlying this phenomenon remain poorly understood. Here we identify the E3 ubiquitin ligase ITCH as a central regulator of Golgi integrity and proteostasis. Elevated ITCH disrupts both cis- and trans-Golgi networks, dislocates lysosomal hydrolase sorting factors, and impairs maturation of hydrolases. The ensuing lysosomal dysfunction leads to autophagosome accumulation and defective clearance of accumulated cytoplasmic toxic proteins like TARDBP/TDP-43. Genetic and pharmacological inhibition of ITCH restores autolysosomal degradation and protects neurons in both mammalian and Drosophila models. Aberrant buildup of the deubiquitinase USP11 drives ITCH accumulation, intensifying neuronal proteotoxic stress in individuals with AD and ALS. These findings reveal a mechanistic pathway connecting Golgi disorganization, autolysosomal impairment, and proteotoxic stress in neurodegeneration.

The targeted degradation of oncogenic or misfolded proteins has emerged as a promising therapeutic strategy. While proteolysis-targeting chimeras (PROTACs) and related technologies have successfully hijacked the ubiquitin-proteasome system to eliminate disease-driving proteins, recent advances highlight the lysosome as a powerful alternative degradation route. Lysosome-based degradation strategies offer broader substrate scope, subcellular targeting flexibility, and the ability to degrade proteins beyond the reach of the proteasome. In this review, we provide a comprehensive overview of synthetic molecules and engineered systems designed to traffic target proteins to the lysosome. These include lysosome targeting chimeras (LYTACs), autophagy-targeting chimeras (AUTACs), autophagy-tethering compounds (ATTECs), and other modalities that exploit endogenous trafficking pathways for selective protein clearance. By mapping the current landscape of lysosome-targeting degraders, this article underscores the therapeutic potential of lysosomal proteolysis and outlines future directions for molecular engineering in this rapidly evolving field.

PINK1-dependent activation of PRKN/parkin on depolarized mitochondria causes mitophagy. The deficiency of NME3, a nucleoside diphosphate kinase/NDPK on the outer mitochondria membrane (OMM), is associated with a fatal neurodegenerative disorder. Here, we report that NME3 deficiency impairs p-S65-ubiquitin (Ub)-dependent PRKN binding on depolarized mitochondria without involving the loss of Ub phosphorylation by PINK1. Our mechanistic investigation revealed that NME3 interacts with PLD6/MitoPLD to generate phosphatidic acid (PA) from cardiolipin on the OMM of damaged mitochondria after depolarization. This lipid signal is essential for positioning MFN2 nearby PINK1 for phosphorylation of Ub conjugates on MFN2, thus enabling the subsequent amplification of PRKN binding to mitochondria. We provide further evidence that mitochondria-endoplasmic reticulum (Mito-ER) tethering prohibits the proximity of MFN2 with PINK1 and PRKN amplification on mitochondria. Importantly, the loss of NME3-regulated PA signal causes Mito-ER tethering. Overall, our findings suggest that NME3 cooperates with PLD6 to generate PA as a critical step in Mito-ER untethering, allowing MFN2 access to PINK1 for p-S65-poly-Ub-dependent feedforward activation of PRKN.Abbreviation ACTB: actin beta; BDNF brain derived neurotrophic factor; CL: cardiolipin; CRISPR: clustered regularly interspaced short palindromic repeats; DAG: diacylglycerol; ER: endoplasmic reticulum; FCCP: carbonyl cyanide p-(trifluoromethoxy) phenylhydrazone; FRET: Förster resonance energy transfer; IF: immunofluorescence; KO: knockout; KD: knockdown; LPIN1: lipin 1; MERCS: mitochondria-endoplasmic reticulum contact sites; MFN2: mitofusin 2; Mito: mitochondria; OMM: outer mitochondrial membrane; p-Ub: phosphorylated ubiquitin; PA: phosphatidic acid; PD: Parkinson disease; PINK1: PTEN induced kinase 1; PLA: proximity ligation assay; PLD6/MitoPLD: phospholipase D family member 6; PRKN: parkin RBR E3 ubiquitin protein ligase; RA: retinoic acid; RT-qPCR: reverse transcription-quantitative polymerase chain reaction; TEM: transmission electron microscopy; TN-NME3: TOMM20-NΔ-NME3; TOMM20: translocase of outer mitochondrial membrane 20; TUBB: tubulin beta class I; Ub: ubiquitin; VDAC: voltage dependent anion channel; WB: western blot.