Autophagy最新文献

BNIP3L/NIX is a mitophagy receptor highly expressed in the brain. Unlike most mitophagy receptors that are recruited to mitochondria only upon stress, BNIP3L constitutively localizes to the mitochondrial outer membrane, suggesting functions beyond stress-induced mitophagy. Here, we identify a non-mitophagic role of BNIP3L in neuronal physiology. Conditional deletion of Bnip3l in glutamatergic neurons of the basolateral amygdala selectively impairs contextual fear memory in mice, a phenotype rescued by both wild-type BNIP3L and a mitophagy-deficient BNIP3L mutant lacking the LC3-interacting region motif. Mechanistically, BNIP3L competitively binds AMP-activated protein kinase (AMPK), thereby relieving AMPK-dependent inhibitory phosphorylation of DNM1L/DRP1 (dynamin 1 like) at Ser637. This interaction promotes rapid mitochondrial fission, supporting synaptic energy availability during memory encoding. Together, these findings reveal a switchable function of BNIP3L in neurons, acting either to acutely regulate mitochondrial dynamics to meet energetic demand or to engage mitophagy when mitochondrial function becomes compromised.

Lipophagy, the selective autophagic degradation of lipid droplets (LDs), is a key mechanism for lipid homeostasis and cellular adaptation to metabolic and stress conditions. In mammals, lipophagy is governed by signaling pathways, LD-associated receptors (e.g. SQSTM1/p62, NBR1, OPTN, SPART, OSBPL8, DDHD2, VPS4A, ATG14, and TP53INP2), and transcription factors (TFEB, TFE3, FOXO1, PPARA, PPARG, and SREBF1/SREBP1) that coordinate LD recognition, sequestration, and lysosomal degradation. Dysregulated lipophagy contributes to the pathogenesis of metabolic and age-related diseases, including metabolic dysfunction-associated steatotic liver disease/nonalcoholic fatty liver disease (MASLD/NAFLD), alcoholic liver disease, diabetes, atherosclerosis, neurodegeneration and cancer. Several recent reviews have discussed lipophagy from different angles, including its roles in metabolic disorders, central nervous system diseases, and fundamental mechanisms across species. In contrast, this review focuses specifically on mammalian lipophagy by synthesizing the latest mechanistic insights into receptor-mediated recognition, transcriptional regulation, and signaling integration. We also outline unresolved questions and conceptual gaps - such as how lipophagy is selectively activated, how it coordinates with lipolysis, and whether distinct receptor codes exist in tissue- and disease-specific contexts - that remain unanswered in the current literature.Abbreviations: AMPK, AMP-activated protein kinase; ATG, autophagy related; ATG8s: mammalian Atg8-family proteins; C1P: ceramide-1-phosphate; CMA, chaperone-mediated autophagy; COPI, coatomer protein complex I; DENV, dengue virus; ER, endoplasmic reticulum; ESCRT: endosomal sorting complex required for transport; FFA: free fatty acid; HOPS, homotypic fusion and vacuole protein sorting; LDs, lipid droplets; LIR: LC3-interacting region; MASLD, metabolic dysfunction-associated steatotic liver disease; MTORC1: mechanistic target of rapamycin kinase complex 1; PE: phosphatidylethanolamine; PEDV: porcine epidemic diarrhea virus; PENV, porcine epidemic diarrhea virus; PtdIns3K-C1: class III phosphatidylinositol 3-kinase complex 1; PtdIns3P, phosphatidylinositol-3-phosphate; ROS, reactive oxygen species; SNARE: soluble NSF attachment protein receptor; SPG54: spastic paraplegia type 54; TAG: triacylglycerol/triglyceride; UBDs, ubiquitin-binding domains.

Despite the clinical success of PDCD1/PD-1 and CD274/PD-L1 immune checkpoint blockade in multiple cancers, its efficacy in colorectal cancer (CRC) remains limited. Here, we report that the combination of the tyrosine kinase inhibitor regorafenib with PDCD1 blockade enhances anti-tumor immunity in CRC, both in clinical observations and preclinical models. Mechanistically, regorafenib acts as a molecular glue, directly promoting the interaction between CD274 and the selective autophagy receptor SQSTM1/p62, leading to SQSTM1-mediated autophagic degradation of CD274 and restoration of T cell-mediated cytotoxicity. In summary, these findings identify a previously unrecognized role of regorafenib in modulating tumor immune evasion and provide a mechanistic rationale for its combination with PDCD1 inhibitors in CRC treatment.Abbreviations: 3-MA: 3-methyladenine; ATG5: autophagy related 5; ATG7: autophagy related 7; CD274/PD-L1: CD274 molecule; CHX: cycloheximide; co-IP: co-immunoprecipitation; CQ: chloroquine; CRC: colorectal cancer; CTLs: cytotoxic T cells; ECD: extracellular domain; GZMB: granzyme B; ICD: intracellular domain; IF: immunofluorescence; IFNG/IFN-γ: interferon gamma; MAP1LC3/LC3: microtubule associated protein 1 light chain 3; mCRC: metastatic colorectal cancer; mIF: multiplex immunofluorescence; MSS: microsatellite stable; ORRs: objective response rates; PDCD1/PD-1: programmed cell death 1; PDCD1i: PDCD1 inhibitor; pMMR: mismatch repair-proficient; PROTACs: proteolysis-targeting chimeras; SPR: surface plasmon resonance; SQSTM1/p62: sequestosome 1; TKI: multikinase inhibitor; TME: tumor microenvironment; WB: western blot; WT: wild-type.

Recently, mitophagy-mediated bone mineralization of mesenchymal stem cells has emerged as another bone formation pattern, but whether mitophagy-mediated bone mineralization shapes craniofacial development remains unknown. Here, we demonstrate that loss of OPTN, a keystone macroautophagy/autophagy receptor, impairs mitophagy and acidic calcium phosphate (ACP) transport in orofacial bone mesenchymal stem cells (OMSCs), leading to craniofacial bone mineralization defects. We substantiate that OPTN undergoes LLPS both in vitro and in vivo, driven by S173 phosphorylation within its intrinsically disordered N-terminal domain (NTD), facilitating the association of OPTN complexes with phagophore membranes. Additionally, the ubiquitin-binding domain (UBD) in OPTN's C-terminal domain (CTD) also promotes LLPS to recruit ubiquitin-modified mitochondria. Physiochemically, mutations at the conserved sites in human OPTN (S173A and D474N) disrupt the OPTN LLPS, as validated in mouse and zebrafish, thereby inhibiting mitophagy and impairing bone mineralization. Together, our findings reveal a new mechanism through which OPTN LLPS couples mitophagy-mediated mineralization to craniofacial bone development, highlighting its potential as a therapeutic target for treating orofacial malformations via modulation of mitophagy.Abbreviations: 1, 6HD: 1, 6-hexanediol; ACP: acidic calcium phosphate; ALP: alkaline phosphatase; ARS: Alizarin Red staining; BFR/BS: bone formation rate per bone surface; Baf-A1: bafilomycin A₁; CCCP: carbonyl cyanide 3-chlorophenylhydrazone; CTD: C-terminal domain; dpf: days post-fertilization; EDS: energy dispersive spectroscopy; FL: full length; FRAP: fluorescence recovery after photobleaching; hpf: 24h post-fertilization; IDR: intrinsically disordered region; IHC: immunohistochemistry; LLPS: liquid-liquid phase separation; LC-MS/MS: liquid chromatography-tandem mass spectrometry; MAR: mineral apposition rate; MS/BS: mineralizing surface per bone surface; NTD: N-terminal domain; ODM: osteogenic differentiation medium; OMSCs: orofacial bone mesenchymal stem cells; OPTN: optineurin; P1: postnatal day 1; P21: postnatal day 21; PDB: Paget disease of bone; PTMs: post-translational modifications; qRT-PCR: quantitative real-time PCR; S173: serine 173; STK4: serine/threonine kinase 4; SEM: scanning electron microscopy; TMD: tissue mineral density; TEM: transmission electron microscopy; UBD: ubiquitin-binding domain; Ub: ubiquitin.

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.