Biology subjects

Hong, H.

Publications and source records attributed to Hong, H..

At least 37 records · Page 2Linked to original sources

bioRxiv2025

Dynamics and Regulation of mRNA Cap Recognition by Human eIF4F

Efficient eukaryotic messenger RNA translation requires dynamic collaboration between the three subunits of initiation factor 4F (eIF4F, eIF4E*G*A), which recognises and activates mRNA at its 5' cap structure for ribosome recruitment. Despite its high biological and pharmacological importance, the dynamics of full human eIF4F-mRNA engagement remain largely uncharacterised, hindering mechanistic understanding of translation initiation and its regulation. Here we observed human eIF4F activity with single-molecule fluorescence assays that directly visualise mRNA cap recognition by its eIF4E subunit. Unexpectedly, we find that inherently transient eIF4E-cap binding is repressed by full-length human eIF4G, predominantly through its C-terminus, representing an unanticipated role for eIF4G as a central rate-limiting factor in the eIF4F complex. This repression is relieved by nucleotide-bound eIF4A in the eIF4F heterotrimer, placing eIF4A as a crucial determinant of efficient cap recognition for translation. Molecular dynamics simulations reveal that electrostatic modulation of eIF4E-mRNA interaction allows eIF4G to control the cap-recognition frequency. Our findings also indicate that intrinsic eIF4F- mRNA dynamics are insufficient to support cap-tethered ribosomal scanning to locate translation start sites. They illuminate fundamental design-principle differences for the overall mechanism and division of labour among eIF4F subunits during mRNA recognition in humans and yeast.

biophysics↗

bioRxiv2025

Modeling Friedreich's ataxia with Bergmann glia-enriched human cerebellar organoids

The human cerebellum is a specialized brain region that is involved in various neurological and psychiatric diseases but has been challenging to study in vitro due its complex neurodevelopment and cellular diversity. Despite the progress in generating neural tissues from human induced pluripotent stem cells (iPSCs), an organoid model that recapitulates the key features of cerebellar development has not been widely established. Here, we report the generation of a 60-day method for human cerebellar organoids (hCBOs) that is characterized by induction of rhombomere 1 (R1) cellular identity followed by derivation of neuronal and glial cell types of the cerebellum. In contrast to forebrain organoids with multiple neural rosettes and inside-out neuronal migration, hCBOs develop a SOX2+ cerebellar plate on the outermost surface of organoids with outside-in neuronal migration, which is a characteristic hallmark of cerebellar histogenesis. These hCBOs produced various other cell types including granule neurons, Purkinje cells, Golgi neurons, and deep cerebellar nuclei. By using a glial induction strategy, we generate Bergmann glial cells (BGCs) within the hCBOs that not only serve as scaffolds for granule cells migration but also enhance electrophysiological response of the hCBOs. Furthermore, by generating hCBOs from patients with Friedreichs ataxia (FRDA), we revealed abnormal disease-specific phenotypes that could be reversed by histone deacetylase (HDAC) inhibitors and gene editing by CRISPR-Cas9. Taken together, our advanced hCBO model provides new opportunities to investigate the molecular and cellular mechanisms of cerebellar ontogenesis and utilize patient-derived iPSCs for translational research.

developmental biology↗

bioRxiv2025

Highly sensitive chemiluminescence imaging of misfolded proteins in neurodegenerative models

Visualizing misfolded proteins would greatly facilitate early diagnosis, etiology elucidation, and therapy monitoring of neurodegeneration. Although several probes have been reported, simple and versatile detection in vivo is still challenging. We demonstrated that both generic and precise detection of misfolded proteins could be achieved with a chemiluminescence probe, ADLumin-1. For the generic aspect, ADLumin-1 was highly sensitive to various misfolded proteins, showing up to 127.73-fold higher signal-to-noise ratio than Thioflavin T. ADLumin-1 could also non-invasively visualize misfolded proteins in mouse models of Parkinsons disease, Alzheimers disease and amyotrophic lateral sclerosis. Furthermore, ADLumin-1 displayed precise detection value for -synuclein by combining with PMCA in vitro and bioorthogonal ChRET imaging technology in vivo. ADLumin-1 can selectively detect -synuclein in CSF at the femtomolar level and enables in situ monitoring of misfolded -synuclein in vivo. Combining generality and precision, our findings could be widely applied in preclinical and clinical studies of neurodegenerative diseases. TeaserA highly sensitive chemiluminescence probe enables both generic and precise detection of various misfolded proteins

biochemistry↗

bioRxiv2025

Noise-induced hearing loss enhances Ca2+-dependent spontaneous bursting activity in lateralcochlear efferents

Exposure to loud and/or prolonged noise damages cochlear hair cells and triggers downstream changes in synaptic and electrical activity in multiple brain regions, resulting in hearing loss and altered speech comprehension. It remains unclear however whether or not noise exposure also compromises the cochlear efferent system, a feedback pathway in the brain that fine-tunes hearing sensitivity in the cochlea. We examined the effects of noise-induced hearing loss on the spontaneous action potential (AP) firing pattern in mouse lateral olivocochlear (LOC) neurons. This spontaneous firing exhibits a characteristic burst pattern dependent on Ca2+ channels, and we therefore also examined the effects of noise-induced hearing loss on the function of these and other ion channels. The burst pattern was sustained by an interaction between inactivating Ca2+ currents contributed largely by L-type channels, and steady outward currents mediated by Ba2+-sensitive inwardly-rectifying and two-pore domain K+ channels. One week following exposure to loud broadband noise, hearing thresholds were significantly elevated, and the duration of AP bursts was increased, likely as a result of an enhanced Ca2+ current. Additional effects of noise-induced hearing loss included alteration of Ca2+-dependent inactivation of Ca2+ currents and a small elevation of outward K+ currents. We propose that noise-induced hearing loss enhances efferent activity and may thus amplify the release of neurotransmitters and neuromodulators (i.e., neuropeptides), potentially altering sensory coding within the damaged cochlea. Significance StatementAlthough the effects of noise-induced hearing loss on the auditory afferent system have been extensively studied, little is known about its impact on the auditory efferent system, which modulates hearing sensitivity via feedback from the brain. Additionally, while Ca2+ channels are related to numerous neurological diseases, their involvement in auditory disorders is underexplored. This study bridges these gaps by examining Ca2+ channel-driven spontaneous burst firing in lateral olivocochlear (LOC) neurons, the most numerous auditory efferent neurons. Noise-induced hearing loss differentially affects Ca2+ channel subtypes by increasing high-voltage activated currents that further prolong burst firing and suggesting altered intracellular Ca2+ signaling. These significant changes in LOC firing behavior may profoundly impact their downstream targets in the cochlea.

neuroscience↗

bioRxiv2024

Landscape profiling of PET depolymerases using a natural sequence cluster framework

Since the demonstration that rapid polyethylene terephthalate (PET) decomposition using enzymes is feasible, a number of efficient depolymerases have been reported with the aim of resolving the plastic pollution issues. However, sporadic studies on enzymes with PET hydrolysis activity hinder the understanding of the distribution of potential PETases hidden in natures repertoire, and subsequently, the identification of potent enzymes. Here, we present the clustering of 1,894 PETase candidates, which include the majority of known PETases, and describe their profiling. An archipelago landscape of 170 lineages shows distribution of 289 representative sequences with features associated with PET-degrading capabilities. A birds-eye view of the landscape identifies three highly promising yet unexplored PETase lineages and two potent PETases, Mipa-P and Kubu-P. The engineered Mipa-PM19 and Kubu-PM12 variants exhibit both high PET hydrolysis activity and thermal stability. In particular, Kubu-PM12 outperformed the engineered benchmarks in terms of PET depolymerization in harsh environments, such as with high substrate load and ethylene glycol as the solvent. Our landscape framework and the identified variants assist in the understanding of how biological processes respond to solid-state and non-natural PET plastics.

systems biology↗

bioRxiv2023

Spatiotemporal Profiling Unveiling the Cellular Organization Patterns and Local Protumoral Immune Microenvironment Remodeling in Early Lung Adenocarcinoma Progression

Spatial cellular organization patterns (COPs) in tumor microenvironment influence the tumor progression and therapeutic response, however, little is known about the cellular composition and functional potential of these multicellular structures during lung adenocarcinoma progression. Here, we integrate spatial transcriptomics with single cell RNA sequencing to characterize the local tumor and immunological landscape of samples from 8 patients with early-stage lung adenocarcinoma at different pathological stages. We identified ten COPs that show distinct associations with local immune states and clinical outcomes, including survival and therapy response. The local infiltration levels of regulatory and dysfunctional immune cells are increased with pathological progression. Cell-to-cell interactions between malignant cells and tumor microenvironment (TME) cells were involved in protumor immune state remodeling. Finally, we detected a group of malignant cells that were specifically located at the tumor boundary, representing a more aggressive state, were involved in the invasion of invasive adenocarcinoma (IAC). Altogether, these results can improve our understanding of the local microenvironment characteristics that underlie LUAD progression and may facilitate the identification of drug targets to prevent invasive progression and biomarkers for diagnosis.

cell biology↗

bioRxiv2023

A telomere-to-telomere genome assembly of Zhonghuang 13, a widely-grown soybean variety from the original center of Glycine max

Soybean (Glycine max) stands as a globally significant agricultural crop, and the comprehensive assembly of its genome is of paramount importance for unraveling its biological characteristics and evolutionary history. Nevertheless, previous soybean genome assemblies have harbored gaps and incompleteness, which have constrained in-depth investigations into soybean. Here, we present the first Telomere-to-Telomere (T2T) assembly of the Chinese soybean cultivar "Zhonghuang 13" (ZH13) genome, termed ZH13-T2T, utilizing PacBio Hifi and ONT ultralong reads. We employed a multi-assembler approach, integrating Hifiasm, NextDenovo, and Canu, to minimize biases and enhance assembly accuracy. The assembly spans 1,015,024,879 bp, effectively resolving all 393 gaps that previously plagued the reference genome. Our annotation efforts identified 50,564 high-confidence protein-coding genes, 707 of which are novel. ZH13-T2T revealed longer chromosomes, 421 not-aligned regions (NARs), 112 structure variations (SVs), and a substantial expansion of repetitive element compared to earlier assemblies. Specifically, we identified 25.67 Mb of tandem repeats, an enrichment of 5S and 48S rDNAs, and characterized their genotypic diversity. In summary, we deliver the first complete Chinese soybean cultivar T2T genome. The comprehensive annotation, along with precise centromere and telomere characterization, as well as insights into structural variations, further enhance our understanding of soybean genetics and evolution.

plant biology↗

bioRxiv2023

Tissue-Specific Dependence of Th1 Cells on the Amino Acid Transporter SLC38A1 in Inflammation

Amino acid (AA) uptake is essential for T cell metabolism and function, but how tissue sites and inflammation affect CD4+ T cell subset requirements for specific AA remains uncertain. Here we tested CD4+ T cell AA demands with in vitro and multiple in vivo CRISPR screens and identify subset- and tissue-specific dependencies on the AA transporter SLC38A1 (SNAT1). While dispensable for T cell persistence and expansion over time in vitro and in vivo lung inflammation, SLC38A1 was critical for Th1 but not Th17 cell-driven Experimental Autoimmune Encephalomyelitis (EAE) and contributed to Th1 cell-driven inflammatory bowel disease. SLC38A1 deficiency reduced mTORC1 signaling and glycolytic activity in Th1 cells, in part by reducing intracellular glutamine and disrupting hexosamine biosynthesis and redox regulation. Similarly, pharmacological inhibition of SLC38 transporters delayed EAE but did not affect lung inflammation. Subset- and tissue-specific dependencies of CD4+ T cells on AA transporters may guide selective immunotherapies. HIGHLIGHTSO_LIT cells dynamically regulate glutamine amino acid transporters when activated C_LIO_LISLC38A1 supports Th1 cell mTORC1 and proliferation by redox and hexosamine pathways C_LIO_LITargeting SLC38A1 does not affect lung inflammation but delays IBD and EAE C_LIO_LINutrient transporter needs of T cell subsets vary based on disease and tissue site C_LI

immunology↗

bioRxiv2023

Density Physics-Informed Neural Network reveals sources of cell heterogeneity in signal transduction

The transduction time between signal initiation and final response provides valuable information on the underlying signaling pathway, including its speed and precision. Furthermore, multimodality in transduction-time distribution informs that the response is regulated by multiple pathways with different transduction speeds. Here, we developed Density physics-informed neural network (Density-PINN) to infer the transduction-time distribution, challenging to measure, from measurable final stress response time traces. We applied Density-PINN to single-cell gene expression data from 16 promoters regulated by unknown pathways in response to antibiotic stresses. We found that promoters with slower signaling initiation and transduction exhibit larger cell-to-cell heterogeneity in response intensity. However, this heterogeneity was greatly reduced when the response was regulated by slow and fast pathways together. This suggests a strategy for identifying effective signaling pathways for consistent cellular responses to disease treatments. Density-PINN can also be applied to understand various time delay systems, including infectious diseases.

systems biology↗

bioRxiv2023

Calcium-sensitive subthreshold oscillations and electrical coupling in principal cells of mouse dorsal cochlear nucleus

In higher sensory brain regions, slow oscillations (0.5-5 Hz) associated with quiet wakefulness and attention modulate multisensory integration, predictive coding, and perception. Although often assumed to originate via thalamocortical mechanisms, the extent to which sub-cortical sensory pathways are independently capable of slow oscillatory activity is unclear. We find that in the first station for auditory processing, the cochlear nucleus, fusiform cells from juvenile mice (of either sex) generate robust 1-2 Hz oscillations in membrane potential and exhibit electrical resonance. Such oscillations were absent prior to the onset of hearing, intrinsically generated by hyperpolarization-activated cyclic nucleotide-gated (HCN) and persistent Na+ conductances (NaP) interacting with passive membrane properties, and reflected the intrinsic resonance properties of fusiform cells. Cx36-containing gap junctions facilitated oscillation strength and promoted pairwise synchrony of oscillations between neighboring neurons. The strength of oscillations were strikingly sensitive to external Ca2+, disappearing at concentrations > 1.7 mM, due in part to the shunting effect of small-conductance calcium-activated potassium (SK) channels. This effect explains their apparent absence in previous in vitro studies of cochlear nucleus which routinely employed high-Ca2+ extracellular solution. In contrast, oscillations were amplified in reduced Ca2+ solutions, due to relief of suppression by Ca2+ of Na+ channel gating. Our results thus reveal mechanisms for synchronous oscillatory activity in auditory brainstem, suggesting that slow oscillations, and by extension their perceptual effects, may originate at the earliest stages of sensory processing. SIGNIFICANCE STATEMENT (120 words max.)Many studies show that electrical activity in higher brain regions is regulated by brain oscillations. Here we show that such oscillatory activity can arise even in the first levels of auditory processing in the cochlear nucleus of the brainstem (fusiform cells), and is generated not by neural networks but by the biophysical properties of individual neurons. Oscillations are highly sensitive to external Ca2+ due to interplay of multiple ionic conductances. Gap junctions between cells allows for amplification and synchrony of such activity. Oscillations are absent in pre-hearing neurons, suggesting that sound activity might be important for their emergence. We propose that such early-level oscillations may serve to enhance signaling associated with particular environmental stimuli.

neuroscience↗

bioRxiv2023

Theranostic Bottle-Brush Polymers Tailored for Universal Solid-Tumour Targeting

Nanomedicines involving nanotechnologies and engineering of nanomaterials for medicines have shown great promise in diagnosis and treatment of diseases including cancers. A major hurdle that limits the successful clinical translation of nanomedicines, however, is how to overcome the cascaded biological barriers and improve the delivery efficacy towards the disease sites and minimize the toxicity against healthy tissues and cells. Here, we report a type of bottle-brush-like polymers systematically optimized in their chemical structures, sizes, and surface charges that lead to their outstanding pharmacokinetics and tumour-targeting performances in a variety of both subcutaneous and orthotopic tumour models. The potential mechanism has been studied by revealing the structure-activity relationship of these polymers in overcoming the biological barriers, including their avoidance by the immune system and deep tumour infiltration. Our study may offer insight for a rational design of highly efficient delivery platform of polymeric nanomedicines that could effectively overcome the cascaded biological barriers and thus lead to high tumour-targeting efficacy and low toxicity.

bioengineering↗

bioRxiv2023

Transcriptome brings variations of gene expression, alternative splicing, and structural variations into gene-scale trait dissection in soybean

Genome-wide association study (GWAS) identifies trait-associated loci, but due in part to slow decay of linkage disequilibrium (LD), identifying the causal genes can be a bottleneck. Transcriptome-wide association study (TWAS) addresses this by identifying gene expression-phenotype associations or integrating gene expression quantitative trait loci (eQTLs) with GWAS results. Here, we used self-pollinated soybean as a model to evaluate the application of TWAS in the genetic dissection of traits in plant species that exhibit slow LD decay. The first RNA-Seq analysis of a soybean diversity panel was conducted, which identified the genetic regulation of 29,286 genes. Different TWAS solutions were less affected by LD and robust with source of expression that identified known genes related to traits from different development stages and tissues. A novel gene named pod color L2 was identified via TWAS and functionally validated by genome editing. Our introduction of the new exon proportion feature significantly improves the capture of expression variations resulting from structural variations and alternative splicing. As a result, the genes identified by our TWAS approach exhibited a diverse range of causal variations, including SNP, insertion/deletion, gene fusion, copy number variation, and alternative splicing. Using our TWAS approach, we identified genes associated with flowering time, including both previously known candidates and novel genes that had not been linked to this trait before, providing complementary insights with GWAS. In summary, this study supports the application of TWAS for candidate gene identification in species with low rates of LD decay.

genetics↗

bioRxiv2023

Small extracellular vesicles promote stiffness-mediated metastasis

Tissue stiffness is a critical prognostic factor in breast cancer and is associated with metastatic progression. Here we show an alternative and complementary hypothesis of tumor progression whereby physiological matrix stiffness affects the quantity and protein cargo of small EVs produced by cancer cells, which in turn drive their metastasis. Primary patient breast tissue produces significantly more EVs from stiff tumor tissue than soft tumor adjacent tissue. EVs released by cancer cells on matrices that model human breast tumors (25 kPa; stiff EVs) feature increased adhesion molecule presentation (ITG2{beta}1, ITG6{beta}4, ITG6{beta}1, CD44) compared to EVs from softer normal tissue (0.5 kPa; soft EVs), which facilitates their binding to extracellular matrix (ECM) protein collagen IV, and a 3-fold increase in homing ability to distant organs in mice. In a zebrafish xenograft model, stiff EVs aid cancer cell dissemination through enhanced chemotaxis. Moreover, normal, resident lung fibroblasts treated with stiff and soft EVs change their gene expression profiles to adopt a cancer associated fibroblast (CAF) phenotype. These findings show that EV quantity, cargo, and function depend heavily on the mechanical properties of the extracellular microenvironment. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=200 SRC="FIGDIR/small/545937v3_ufig1.gif" ALT="Figure 1"> View larger version (42K): org.highwire.dtl.DTLVardef@1be1dbdorg.highwire.dtl.DTLVardef@928710org.highwire.dtl.DTLVardef@1e14e9borg.highwire.dtl.DTLVardef@efdb7f_HPS_FORMAT_FIGEXP M_FIG C_FIG

cancer biology↗

bioRxiv2023

Lipid Bilayer Strengthens the Cooperative Network of a Membrane-Integral Enzyme

Although membrane proteins fold and function in a lipid bilayer constituting cell membranes, their structure and functionality can be recapitulated in diverse amphiphilic assemblies whose compositions deviate from native membranes. It remains unclear how various hydrophobic environments can stabilize membrane proteins and whether lipids play any role therein. Here, using the evolutionary unrelated -helical and {beta}-barrel membrane proteins of Escherichia coli, we find that the hydrophobic thickness and the strength of amphiphile- amphiphile packing are critical environmental determinants of membrane protein stability. Lipid solvation enhances stability by facilitating residue burial in the protein interior and strengthens the cooperative network by promoting the propagation of local structural perturbations. This study demonstrates that lipids not only modulate membrane proteins stability but also their response to external stimuli.

biophysics↗

bioRxiv2023

GPR4 knockout attenuates intestinal inflammation and forestalls the development of colitis-associated colorectal cancer in murine models

GPR4 is a proton-sensing G protein-coupled receptor highly expressed in vascular endothelial cells and has been shown to potentiate intestinal inflammation in murine colitis models. Herein, we evaluated the proinflammatory role of GPR4 in the development of colitis-associated colorectal cancer (CAC) using the dextran sulfate sodium (DSS) and azoxymethane (AOM) mouse models in wild-type and GPR4 knockout mice. We found GPR4 contributed to chronic intestinal inflammation and heightened DSS/AOM-induced intestinal tumor burden. Tumor blood vessel density was markedly reduced in mice deficient in GPR4 which correlated with increased tumor necrosis and reduced tumor cell proliferation. These data demonstrate GPR4 ablation alleviates intestinal inflammation and reduces tumor angiogenesis, development, and progression in the AOM/DSS mouse model. Author summaryInflammatory bowel disease (IBD), including ulcerative colitis and Crohns disease, is a debilitating condition with chronic inflammation in the digestive tract. Patients with IBD are at higher risk of developing colitis-associated colorectal cancer (CAC), compared with the general population. The etiology of IBD is not well understood, but both genetic and environmental factors have been implicated. In this study, we investigated the role of the pH-sensing GPR4 receptor in colitis and CAC using the DSS and AOM induced mouse models. GPR4 knockout alleviated intestinal inflammation, reduced tumor angiogenesis, and impeded CAC development. Our data suggest that inhibition of GPR4 may be explored as a potential therapeutic approach for IBD treatment and CAC prevention.

cancer biology↗

bioRxiv2022

Inferring delays in partially observed gene regulatory networks

MotivationCell function is regulated by gene regulatory networks (GRNs) defined by protein-mediated interaction between constituent genes. Despite advances in experimental techniques, we can still measure only a fraction of the processes that govern GRN dynamics. To infer the properties of GRNs using partial observation, unobserved sequential processes can be replaced with distributed time delays, yielding non-Markovian models. Inference methods based on the resulting model suffer from the curse of dimensionality. ResultsWe develop a simulation-based Bayesian MCMC method for the efficient and accurate inference of GRN parameters when only some of their products are observed. We illustrate our approach using a two-step activation model: An activation signal leads to the accumulation of an unobserved regulatory protein, which triggers the expression of observed fluorescent proteins. With prior information about observed fluorescent protein synthesis, our method successfully infers the dynamics of the unobserved regulatory protein. We can estimate the delay and kinetic parameters characterizing target regulation including transcription, translation, and target searching of an unobserved protein from experimental measurements of the products of its target gene. Our method is scalable and can be used to analyze non-Markovian models with hidden components. AvailabilityAccompanying code in R is available at https://github.com/Mathbiomed/SimMCMC. Contactjaekkim@kaist.ac.kr or kresimir.josic@gmail.com or cbskust@korea.ac.kr Supplementary informationSupplementary data are available at Bioinformatics online.

bioinformatics↗

bioRxiv2022

Balance-directed protein engineering of IsPETase enhances both PET hydrolysis activity and thermostability

A mesophilic PETase from Ideonella sakaiensis (IsPETase) has been shown to exhibit high PET hydrolysis activity, but its low thermostability limits its industrial applications. We herein developed an engineering strategy for IsPETase to enhance PET hydrolysis activity, thermostability, and protein folding of the enzyme. Balance-directed Z1-PETase variant outperforms the stability-directed Z2-PETase variant under both mesophilic and thermophilic conditions, although Z2-PETase exhibits higher thermostability than Z1-PETase. The Z1-PETase is also superior to Fast-PETase, Dura-PETase, and LC-CICCG in terms of depolymerization rate regardless of temperature conditions we tested. Thus, maintaining a balance between PET hydrolysis activity and thermostability is essential for the development of high-performance PET hydrolases. In a pH-stat bioreactor, Z1-PETase depolymerized >90% of both transparent and colored post-consumer PET powders within 24 and 8 hours at 40{degrees}C and 55{degrees}C, respectively, demonstrating that the balance-directed IsPETase variant produced herein may be applicable in the bio-recycling of PET.

bioengineering↗

bioRxiv2022

The critical role of BTRC in hepatic steatosis as an ATGL E3 ligase

ObjectiveNon-alcoholic fatty liver disease (NAFLD), characterized by hepatic steatosis, is one of the most common causes of liver dysfunction. ATGL is closely related to hepatic steatosis as the speed-limited triacylglycerol lipase. Nevertheless, the expression and regulation of ATGL in NAFLD remain unclear. MethodsUsing immunohistochemistry and qRT-PCR to detect the expression of ATGL and BTRC in different models with hepatic steatosis. Co-IP evaluated the binding of ATGL and BTRC. Knockdown of BTRC employed by adenoviruses and then analyzed the ATGL expression, triglyceride levels, and lipid droplets accumulation. ResultsOur results revealed that ATGL protein level was decreased in animal and cellular models of hepatic steatosis and the liver tissues of cholangioma/hepatic carcinoma patients with hepatic steatosis, while the ATGL mRNA level had hardly changed; which means the decreased ATGL mainly degraded through the proteasome pathway. BTRC was identified as the E3 ligase for ATGL, up-regulated, and negatively correlated with ATGL level. Moreover, adenovirus-mediated knockdown of BTRC ameliorated hepatic steatosis via up-regulating ATGL level. ConclusionsOur study demonstrates a crucial role of elevated BTRC in hepatic steatosis through promoting ATGL proteasomal degradation as a new ATGL E3 ligase and suggests BTRC may serve as a potential therapeutic target for NAFLD. FundingThis study was supported by The National Natural Science Foundation of China (Grants 82070888, 82070882, 82100917, 81872165, 82273116, 82203661, 81901557 and 81902693); Key Project of Nature Science Foundation of Guangdong Province, China (Grant 2019B1515120077); National Key R&D Program of China (Grant 2018YFA0800403); Guangdong Special Support Program for Young Top Scientist (Grant 201629046); Guangdong Natural Science Fund (Grant 2019A1515011810, 2021A1515010434, 2022A1515012423 and 2022A1515012513); Key Sci-Tech Research Project of Guangzhou Municipality (Grants 202201010820) Fundamental Research Funds for the Central Universities (Grant 50000-31620106); China Postdoctoral Science Foundation (Grant 2021M703679, 2020M683110).

cell biology↗