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Liu, Y.

Publications and source records attributed to Liu, Y..

At least 1,045 records · Page 58Linked to original sources

Exploring Protein-DNA Binding Residue Prediction and Consistent Interpretability Analysis Using Deep Learning

AO_SCPLOWBSTRACTC_SCPLOWAccurately identifying DNA-binding residues is a crucial step in developing computational tools to model DNA-protein binding properties, which is essential for binding pocket discovery and related drug design. Although several tools have been developed to predict DNA-binding residues based on protein sequences and structures, their performance remains limited, and proteins with crystal structures still represent only a small fraction of DNA-binding proteins. Additionally, the process of extracting handcrafted features for protein representation is labor-intensive. In this study, we combined the strengths of pre-trained protein language models and attention mechanisms to propose a sequence-based method: an attention-based deep learning approach for accurately predicting DNA-binding residues, incorporating a contrastive learning module. Our method outperformed all other sequence-based models across two prevalent benchmark datasets. Furthermore, we developed a structure-based graph neural network (GNN) model to demonstrate the impact of the contrastive module. A common limitation of existing models is their lack of interpretability, which hinders our ability to understand what these models have learned. To address this, we introduced a novel perspective for interpreting our sequence-based model by analyzing the consistency between attention scores and the edge weights generated by the GNN model. Interestingly, our results show that large-scale pre-trained protein language models, together with attention mechanisms, can effectively capture structural information solely from protein sequence inputs.

bioinformatics↗

High-throughput two-photon volumetric brain imaging in freely moving mice

Imaging neural activities across large volumes at subcellular resolution without impeding animal behaviors remains difficult. Here, we develop a high-throughput miniature Bessel-beam two-photon microscope (miniBB2p) capable of imaging calcium dynamics from neurons and dendrites over a volume of 420 x 420 x 80 m3 during free behavior. We share a full description of miniBB2p and demonstrate its ability to perform large-scale recordings of the calcium activities of more than 1000 neurons at a time in anterior cingulate cortex and secondary motor cortex of freely moving mice in various behavioral paradigms. Our results indicate that miniBB2p opens new avenues in the design of miniature multiphoton microscopes, facilitating precise monitoring of neural activities across large populations within a three-dimensional volume in freely moving animals.

neuroscience↗

Liver CYP4A autophagic-lysosomal degradation (ALD): A major role for the autophagic receptor SQSTM1/p62 through an uncommon target interaction site

The hepatic P450 hemoproteins CYPs 4A are typical N-terminally anchored Type I endoplasmic reticulum (ER)-proteins, that are inducible by hypolipidemic drugs and other "peroxisome proliferators". They are engaged in the {omega}-/{omega}-1-oxidation of various fatty acids including arachidonic acid, prostaglandins and leukotrienes and in the biotransformation of some therapeutic drugs. Herein we report that of the mammalian liver CYPs 4A, human CYP4A11 and mouse Cyp4a12a are preferential targets of the ER-lysosome-associated degradation (ERLAD). Consequently, these proteins are stabilized both as 1%Triton X100-soluble and -insoluble species in mouse hepatocytes and HepG2-cells deficient in the autophagic initiation ATG5-gene. Although these proteins exhibit surface LC3-interacting regions (LIRs) that would target them directly to the autophagosome, they nevertheless interact intimately with the autophagic receptor SQSTM1/p62. Through structural deletion analyses and site-directed mutagenesis, we have identified the Cyp4A-interacting p62 subdomain to lie between residues 170 and 233, which include its Traf6-binding and LIM-binding subdomains. Mice carrying a liver-specific genetic deletion of p62 residues 69-251 (p62Mut) that includes the CYP4A-interacting subdomain also exhibit Cyp4a-protein stabilization both as Triton X100-soluble and -insoluble species. Consistently, p62Mut mouse liver microsomes exhibit enhanced {omega}- and {omega}-1-hydroxylation of arachidonic acid to its physiologically active metabolites 19- and 20-HETEs relative to the corresponding wild-type mouse liver microsomes. Collectively, our findings suggest that any disruption of CYP4A ERLAD results in functionally active P450 protein and consequent production of proinflammatory metabolites on one hand, and insoluble aggregates on the other, which may contribute to pathological aggregates i.e. Mallory-Denk bodies/inclusions, hallmarks of many liver diseases.

cell biology↗

Integrated scFv identification and CAR T cell generation for AML targeting in vivo

Cancer immunotherapy has witnessed remarkable advancements, especially in the development of chimeric antigen receptor (CAR) T cell therapy. Here, we integrated single-chain variable fragment (scFv) development with CAR T cell generation based on a newly developed scFv phagemid library. High-throughput long-read PacBio sequencing identified 4.5 x 107 unique full-length scFv proteins within the generated library. In a proof of principle, we screened for scFvs targeting C-type lectin-like molecule-1 (CLL1) with subsequent cloning into a third generation retroviral CAR backbone. Functional assays revealed the specificity and potency of these CAR T cells in targeting CLL1-positive AML cells in vitro. In vivo studies reduced tumor burden and improved survival rates compared to controls. Taken together, screening for tumor specific scFvs against CLL1 can rapidly generate AML specific CAR T cells with effective tumor killing in vivo.

immunology↗

IgG autoantibodies in bullous pemphigoid directly induce a pathogenic MyD88-dependent pro-inflammatory response in keratinocytes:

AbstractWhile autoantibodies in bullous pemphigoid (BP) are known to activate the innate immune response, their direct effect on keratinocytes, and the contribution of BP-IgG autoantibody-dependent keratinocyte responses to BP pathology is largely unknown. Herein, we performed multiplex immunoassays and bulk RNA-seq on primary keratinocytes treated with IgG from BP patients or controls. We identified a pro-inflammatory and proteolytic response with release of several cytokines (IL-6, IL-24, TGF-{beta}1), chemokines (CXCL16, CTACK, MIP-3{beta}, RANTES), C1s, DPP4, and MMP-9. We further validated this response using spatial transcriptomics and scRNA-seq of diseased and control skin. Blistering itself appeared to be major driver of this inflammatory response, with attached BP skin and spongiotic dermatitis revealing highly similar transcriptomes. Based on elevated levels of MyD88 and MyD88-dependent cytokines, we studied the impact of MyD88 deficiency in keratinocytes and demonstrated that MyD88 regulates BP-IgG-induced expression of IL-8, IL-24, and MMP-9. Induction of experimental BP in mice with Krt14-specific Myd88 knockout revealed significantly decreased disease severity with decreased serum levels of IL-1{beta}, IL-4, and IL-9 indicating the contributory role of keratinocyte-derived skin inflammation towards systemic response. Our work demonstrates the key contributions of keratinocyte and MyD88 dependent signaling in response to autoantibodies in BP. Key Messages-IgG antibodies from bullous pemphigoid (BP) patients induce significant upregulation of several inflammatory markers in keratinocytes including cytokines (IL-6, IL-24, TGF-{beta}1), chemokines (CXCL16, CTACK, MIP-3{beta}, RANTES), C1s, DPP4, and MMP9. Several of these markers, including IL-8, IL-24, and MMP9 are regulated by MyD88. -Spatial transcriptomics reveals that BP patient blistered skin demonstrated similar transcriptomic profiles to BP-IgG-treated keratinocytes. With attached skin demonstrating a comparable transcriptome to that seen in spongiotic dermatitis. -In a mouse BP model, keratinocyte-specific MyD88 deficiency results in decreased disease severity with a subsequent decrease in serum IL-1{beta}, IL-4, and IL-9 levels. Capsule summaryIgG from patients with bullous pemphigoid (BP) induces a pro-inflammatory response in keratinocytes, indicating their direct role in driving the inflammatory response in BP.

immunology↗

Gender- and Age-Based Characterization and Comparison of the Murine Primary Peritoneal Mesothelial Cell Proteome

Organs in the abdominal cavity are covered by a peritoneal membrane, which is comprised of a monolayer of mesothelial cells (MC). Diseases involving the peritoneal membrane include peritonitis, primary cancer (mesothelioma), and metastatic cancers (ovarian, pancreatic, colorectal). These diseases have gender- and/or age-related pathologies; however, the impact of gender and age on the peritoneal MC is not well evaluated. To address this, we identified and characterized gender- and age-related differences in the proteomes of murine primary peritoneal MC. Primary peritoneal MC were isolated from young female (FY) or male (MY) mice (3-6 months) and aged female (FA) or male (MA) mice (20-23 months), lysed, trypsin digested using S-Traps, then subjected to bottom-up proteomics using an LC-Orbitrap mass spectrometer. In each cohort, we identified >1000 protein groups. Proteins were categorized using Gene Ontology and pairwise comparisons between gender and age cohorts were conducted. This study establishes baseline information for studies on peritoneal MC in health and disease at two physiologic age/gender points. Segregation of the data by gender and age could reveal novel factors to specific disease states involving the peritoneum. [This in vitro primary cell model has utility for future studies on the interaction between the mesothelium and foreign materials.] SUMMARY STATEMENTMany diseases initiate from or involve peritoneal mesothelial cells including peritonitis, primary cancer (mesothelioma) and metastatic cancers. Progression of these diseases is influenced by many host factors including gender and age; however, the influence of these factors on the peritoneal mesothelial cell proteome has not been evaluated. This study provides novel information and identifies proteins exclusive to both male and female young and aged cohorts. Given the importance of the peritoneal mesothelial cell in abdominal homeostasis, and the impact of gender and age on disease progression, these data will be key for future studies examining mesothelium in both health and disease.

cancer biology↗

Engineering liposomes with cell membrane proteins to disrupt melanosome transfer

Cells communicate by transporting vesicles and organelles, essential for maintaining cellular homeostasis. However, excessive vesicle transfer can cause several diseases and medical conditions like hyperpigmentation due to an unregulated intercellular transfer of melanosomes. Current treatments often focus on eliminating the compartment contents with drugs but can cause significant side effects. Here, we engineer liposomes with cell membrane proteins to directly disrupt intercellular transport without specialized therapeutics. We demonstrate this approach by reducing melanosome transfer from melanocytes to keratinocytes. To achieve this, we incorporate keratinocyte cell membrane proteins into liposomes using microfluidics, which can enhance uptake by melanocytes while reducing uptake by keratinocytes. We also show that these engineered liposomes reduce melanosome transfer because they attach to the surface of pigment globules, impeding pigment globule uptake by keratinocytes. Our findings provide an effective strategy for reducing melanosome transfer to treat hyperpigmentation and introduce a drug-free approach for regulating cellular communication via extracellular vesicles and organelles.

biophysics↗

Gene encoding CC-NBS-LRR protein on rye chromosome 1RS confers wheat stripe rust resistance

Stripe rust, a globally widespread disease, stands as one of the most significant threats to wheat cultivation. The 1BL/1RS translocation, renowned for its robust resistance to both rust and powdery mildew, has historically played an important role in wheat breeding and production. The gene for resistance to stripe rust on the 1RS is known as Yr9 and plays an important role in the production of wheat, but over the course of long-term breeding had lost its resistance due to the evolution of stripe rust towards greater and greater virulence. In this paper, we cloned the stripe rust resistance gene, Yr9, from triticale by genetic mapping approach. The Yr9 encodes a typical nucleotide-binding leucine-rich repeat (NLR) protein. Both transgenic and overexpression of Yr9 in highly stripe rust susceptible wheat varieties conferred complete resistance to the stripe rust races CYR17 and partial resistance to the stripe rust races CYR32, CYR33, and CYR34. In addition, the Yr9 allele in the 1BL/1RS translocation line also showed the same level of resistance to stripe rust. Both two alleles loses resistance when deployed in the field or inoculated with mixed physiological races collected from the field. Our findings provide valuable insights for breeders to strategically incorporate disease resistance genes and provides a foundation for further understanding how pathogenic bacteria might evolve to evade recognition via NLR type proteins. SignificanceThe 1BL/1RS translocation between wheat and rye is the most successful case of exogenous gene application in plant genetic improvement and has been used in wheat breeding for over 50 years. Here we report the cloning of a stripe rust resistance gene Yr9 located on rye chromosome 1RS using a triticale population. The Yr9 encodes a coiled-coil nucleotide-binding site leucine-rich repeat (CC-NBS-LRR) protein that show complete resistance to the stripe rust races CYR17 and partial resistance to the stripe rust races CYR32, CYR33, and CYR34, albeit demonstrating susceptibility under field conditions. Our findings position Yr9 as an ideal candidate gene to study the mechanism of inactivation of disease resistance genes as a result of pathogen evolution.

genetics↗

Endogenous Huntingtin aggregates are a huge organized scaffold and mold for Golgi apparatus impaired by mutant Huntingtin protein

Abstract Huntingtin (HTT) is a naturally aggregating protein that causes Huntington's disease (HD) when its polyglutamine (polyQ) tract exceeds 38 repeats. Despite its importance, the biology of HTT aggregates remains poorly defined. Here, using high resolution imaging of cells derived from HD families, we redefine polyQ assemblies, traditionally regarded as pathogenic aggregates, as dynamic and structurally organized intracellular compartments resembling knitted-fabric patches. These assemblies closely associate with and encircle the Golgi apparatus, integrating Golgi ribbons and stacks to form a previously unrecognized polyQ assembly-Golgi complex. Mechanistically, fragmentation of polyQ assemblies is dynamically coupled with mitotic Golgi fragmentation, whereas inhibition of ADP-ribosylation factor (ARF) function by Brefeldin A disrupts and fragments the complex, revealing an intimate structural and functional coupling between polyQ assemblies and Golgi architecture. The presence of mutant HTT (mHTT) destabilizes these assemblies and complexes, altering their response to nutrient deprivation and autophagy enhancers but not to antisense oligonucleotide (ASO) therapy. Functionally, polyQ assemblies in HD cells compromise the scaffolding capacity of the Golgi apparatus, clathrin-coated vesicles, and ARF1, impair Golgi glycosylation, and promote aberrant neuronal firing activity. Collectively, these findings establish polyQ assemblies as dynamic structural regulators of Golgi organization and function and demonstrate that mHTT disrupts the homeostatic dynamics of the polyQ assembly-Golgi complex, leading to Golgipathy.

pathology↗

Improving diffusion-based protein backbone generation with global-geometry-aware latent encoding

Recent breakthroughs in diffusion-based generative models have prompted de novo protein design, notably in generating diverse and realistic structures. Nevertheless, while existing models either excel at unconditional generation or employ residue-wise conditioning for topological control, explorations on a holistic, top-down approach to control the overall topological arrangements is still limited. In response, we introduce TopoDiff, a diffusion-based framework augmented by a structure encoder and a latent sampler. Our model can unsupervisedly learn a compact latent representation of protein global geometry, while simultaneously integrating a diffusion module to leverage this information for controlled structure generation. In benchmark against existing models, TopoDiff demonstrates comparable performance on established metrics and exhibits an improved coverage over the fold modes of natural proteins. Moreover, our method enables versatile control at the global-geometry level for structural generation, under the assistance of which we derived a number of novel folds of mainly-beta proteins with comprehensive experimental validation.

bioengineering↗

EGDiff: An Experiment-Guided Diffusion model for protein conformational ensemble generation

Understanding protein conformation is key to understanding their function. Importantly, most proteins adopt multiple conformations with non-trivial ensemble distributions that change depending on their environment to perform functions like catalysis, signaling, and transport. Recently, machine learning techniques, especially deep generative models, have been employed to develop protein conformation generators. These models, known as unified protein ensemble samplers, are trained on the PDB dataset and can generate diverse protein conformation ensembles given a protein sequence. However, their reliance solely on structural data from the PDB, which primarily captures folded protein states, restricts the diversity of the generated ensembles and can result in physically unrealistic conformations. In this paper, we overcome these challenges by introducing ExEnDiff, an experiment-guided diffusion model for protein conformation generation. ExEnDiff integrates experimental measurements as a physical prior, enabling the generation of protein conformations with desired properties. Our experiments on a variety of fast-folding and intrinsically disordered proteins demonstrate that ExEnDiff significantly advances the capabilities of current unified protein ensemble samplers. With little computational cost, ExEnDiff can capture important proteins configuration properties and the underlying Boltzmann distribution, paving the way for a next-generation molecular dynamics engine. We further demonstrate the effectiveness of ExEnDiff to capture conformational changes in the presence of mutations and as an efficient tool for determining a reasonable CV space for protein ensembles. With these results, ExEnDiff is well-poised to push the study of protein ensembles into a data-rich regime currently available to few problems in biology.

biophysics↗

Efficacy of photodynamic therapy using 5-aminolevulinic acid-induced photosensitization is enhanced in pancreatic cancer cells with acquired drug resistance

The use of 5-aminolevulinic acid (ALA) as a precursor for protoporphyrin IX (PpIX) is an established photosensitization strategy for photodynamic therapy (PDT) and fluorescence guided surgery. Ongoing studies are focused on identifying approaches to enhance PpIX accumulation as well as to identify tumor sub-types associated with high PpIX accumulation. In this study, we investigated PpIX accumulation and PDT treatment response with respect to nodule size in 3D cultures of pancreatic cancer cells (Panc1) and a derivative subline (Panc1OR), which has acquired drug resistance and exhibits increased epithelial mesenchymal transition. In monolayer and 3D culture dose response studies the Panc1OR cells exhibit significantly higher cell killing at lower light doses than the drug naive cells. Panc1OR also exhibits increased PpIX accumulation. Further analysis of cell killing efficiency per molecule of intracellular PpIX indicates that the drug resistant cells are intrinsically more responsive to PDT. Additional investigation using exogenous delivery of PpIX also shows higher cell killing in drug resistant cells, under conditions which achieve approximately the same intracellular PpIX. Overall these results are significant as they demonstrate that this example of drug-resistant cells associated with aggressive disease progression and poor clinical outcomes, show increased sensitivity to ALA-PDT.

cancer biology↗

Mitigation of multi-scale biases in cell-type deconvolution for spatially resolved transcriptomics using HarmoDecon

The advent of spatially resolved transcriptomics (SRT) has revolutionized our understanding of tissue molecular microenvironments by enabling the study of gene expression in its spatial context. However, many SRT platforms lack single-cell resolution, necessitating cell-type deconvolution methods to estimate cell-type proportions in SRT spots. Despite advancements in existing tools, these methods have not addressed biases occurring at three scales: individual spots, entire tissue samples, and discrepancies between SRT and reference scRNA-seq datasets. These biases result in overbalanced cell-type proportions for each spot, mismatched cell-type fractions at the sample level, and data distribution shifts across platforms. To mitigate these biases, we introduce HarmoDecon, a novel semi-supervised deep learning model for spatial cell-type deconvolution. HarmoDecon leverages pseudo-spots derived from scRNA-seq data and employs Gaussian Mixture Graph Convolutional Networks to address the aforementioned issues. Through extensive simulations on multi-cell spots from STARmap and osmFISH, HarmoDecon outperformed 11 state-of-the-art methods. Additionally, when applied to legacy SRT platforms and 10x Visium datasets, HarmoDecon achieved the highest accuracy in spatial domain clustering and maintained strong correlations between cancer marker genes and cancer cells in human breast cancer samples. These results highlight the utility of HarmoDecon in advancing spatial transcriptomics analysis.

bioinformatics↗

Automated Tumor and FUS Lesion Quantification on Multi-frequency Harmonic Motion and B-mode Imaging Using a Multi-modality Neural Network

Harmonic Motion Imaging (HMI) is an ultrasound elasticity imaging method that measures the mechanical properties of tissue using amplitude-modulated acoustic radiation force (AM-ARF). By estimating tissues on-axis oscillatory motion, HMI-derived displacement images represent localized relative stiffness and can predict the tumor response to neoadjuvant chemotherapy (NACT) and monitor focused ultrasound (FUS) ablation therapy. Multi-frequency HMI (MF-HMI) excites tissue at various AM frequencies simultaneously, which allows for image optimization without prior knowledge of inclusion size and stiffness. However, challenges remain in size estimation as inconsistent boundary effects result in different perceived sizes across AM frequencies. Herein, we developed an automated tumor and FUS lesion quantification method using a transformer-based multi-modality neural network, HMINet. It was trained on 380 pairs of MF-HMI and B-mode images of phantoms and in vivo orthotopic breast cancer mice (4T1). Test datasets included phantoms (n = 32), in vivo 4T1 mice (n = 24), breast cancer patients (n = 16), and a FUS-induced lesion, with average segmentation accuracy (Dice Similarity Score) of 0.95, 0.86, 0.82, and 0.87, respectively. To increase the generalizability of HMINet, we applied a transfer learning strategy, i.e., fine-tuning the model using patient data. For NACT patients, the displacement ratios (DR) between the tumor and surrounding tissue were calculated based on HMINet-segmented boundaries to predict tumor response based on stiffness changes.

bioengineering↗

STAMP: Single-Cell Transcriptomics Analysis and Multimodal Profiling through Imaging

We introduce Single-Cell Transcriptomics Analysis and Multimodal Profiling (STAMP), a scalable profiling approach of individual cells. Leveraging transcriptomics and proteomics imaging platforms, STAMP eliminates sequencing costs, to enable single-cell genomics from hundreds to millions of cells at an unprecedented low cost. Stamping cells in suspension onto imaging slides, STAMP supports single-modal (RNA or protein) and multimodal (RNA and protein) profiling and flexible, ultra-high-throughput formats. STAMP allows the analysis of a single or multiple samples within the same experiment, enhancing experimental flexibility, throughput and scale. We tested STAMP with diverse sample types, including peripheral blood mononuclear cells (PBMCs), dissociated cancer cells and differentiated embryonic stem cell cultures, as well as whole cells and nuclei. Combining RNA and protein profiling, we applied immuno-phenotyping of millions of blood cells simultaneously. We also used STAMP to identify ultra-rare cell populations, simulating clinical applications to identify circulating tumor cells (CTCs). Performing in vitro differentiation studies, we further showed its potential for large-scale perturbation studies. Together, STAMP establishes a new standard for cost-effective, scalable single-cell analysis. Without the need for sequencing, STAMP makes high-resolution profiling more affordable and accessible. Designed to meet the needs of research labs, diagnostic cores and pharmaceutical companies, STAMP holds the promise to transform our capacity to map human biology, diagnose diseases and drug discovery.

genomics↗

Cell extract-based in vitro DNA replication enables sustainable cell-free gene expression

Cell extract-based cell-free gene expression (CFE) systems break cellular boundaries and create emerging platforms for synthetic biology applications. However, these systems lack intrinsic DNA replication capability, thereby limiting sustained transcription and translation in a cell-free environment. Here, we introduce a LoopReX system based on E. coli CFE by integration of the DNA replication machinery, enabling iterative in vitro DNA replication and sustainable cell-free gene expression. We establish LoopReX by integrating phi29 DNA polymerase into the crude lysate-based E. coli CFE system, allowing for coupled DNA replication and protein expression. We elucidate the synergetic mechanisms between T7 RNA polymerase and phi29 DNA polymerase in facilitating in vitro DNA replication. Additionally, we optimize LoopReX reaction conditions by machine learning strategies. Finally, we demonstrate that the enhanced LoopReX system achieves highly efficient DNA replication and protein production in an iterative, scalable, and sustainable manner. We anticipate that LoopReX will significantly advance the application of CFE in synthetic biology.

synthetic biology↗

Multi-omics analysis reveals the mechanism of BnC07MYB3a is involved in seed coat color in Brassica napus L.

In rapeseed (Brassica napus), yellow-seeded varieties accumulate less flavonoid pigments (anthocyanins/proanthocyanidins) in their seed coats compared with black-seeded varieties. The yellow-seeded trait is associated with greatly improved seed oil yield, quality, and commercial value. Many R2R3 MYB activators have been characterized in rapeseed, but how MYB-type repressors affect pigment biosynthesis is not yet fully understood. In this study, we performed transcriptome sequencing and metabolomic analysis of B. napus varieties with extreme differences in seed coat color, combined with weighted gene co-expression network analysis. This analysis identified an R2R3-MYB-type transcription factor, BnC07MYB3a (BnaC07G0178800ZS), as a candidate regulator of the yellow-seeded trait in B. napus. Overexpressing BnC07MYB3a in Arabidopsis thaliana and B. napus downregulated the expression of flavonoid biosynthetic genes, resulting in significantly lower anthocyanin and proanthocyanidin accumulation than in the wild-type and a lighter seed coat color in transgenic plants. BnC07MYB3a directly binds to the promoter of the TRANSPARENT TESTA (TT) gene BnTT6 and represses its expression. BnC07MYB3a also physically interacts with BnA06bHLH92a and the WD40 transcription factor TRANSPARENT TESTA GLABRA1 (BnTTG1), suggesting that they might form a previously unidentified MYB-bHLH-WD40 transcription factor complex. Our results reveal the molecular mechanism and regulatory network of BnC07MYB3a in determining seed coat color in B. napus and provide a genetic resource for breeding yellow-seeded cultivars of B. napus.

molecular biology↗

Characterization of Autophagy Cargo Profiles during Starvation and Exercise with a Novel Autophagosome Isolation Method

Autophagy is a cellular process to clear unwanted and dysfunctional cellular cargoes, which are sequestered in autophagosomes before their delivery to lysosomes for degradation. Autophagy cargo selection, mediated by cargo receptors, varies across cell types and conditions. Understanding the cargo features is essential for elucidating autophagys function in specific physiological or pathological contexts. Here we present a simple and rapid method for isolating LC3B-positive autophagosomes from the tissues of GFP-LC3 transgenic mice, a widely used autophagy reporter model, without relying on the complex ultracentrifugation steps required by traditional methods. When combined with quantitative proteomics, this approach enables efficient in vivo characterization of autophagy cargoes. We applied this method to establish autophagy cargo profiles in skeletal muscle during starvation and exercise, two physiological conditions that activate autophagy, and identified distinct cargo selection patterns, with significantly higher levels of ER-phagy and ribophagy observed during starvation. We further revealed the ER-phagy receptors TEX264 and RETREG1/FAM134B as potential mediators of the elevated ER-phagy under starvation. In summary, we report an efficient workflow for in vivo autophagy cargo characterization and provide detailed analysis and comparison of cargo profiles under starvation and exercise conditions.

cell biology↗