Biology subjects

Chen, N.

Publications and source records attributed to Chen, N..

At least 109 records · Page 6Linked to original sources

bioRxiv2022

Hydrological dynamics drive the transition of antibiotic resistance genes between particle-attached and free-living lifestyles in a deep freshwater reservoir

Despite the growing awareness of antibiotic resistance genes (ARGs) spreading in the environment, there is a knowledge gap on the fate and transport of ARGs in particle-attached (PA) and free-living (FL) lifestyles in deep freshwater ecosystems experiencing seasonal hydrological changes. Here, we examined the ARG profiles using high-throughput quantitative PCR in PA and FL lifestyles at four seasons representing two hydrological seasons (i.e., vertical mixing and thermal stratification) in the Shuikou Reservoir (SR), Southern China. The results indicated that seasonal hydrological dynamics were critical for influencing ARGs in PA and FL fractions, and the transition of ARGs between the two lifestyles. Although both PA and FL ARG profiles were likely to be shaped by horizontal gene transfer, PA and FL ARGs had different responses to the changes in physico-chemicals (e.g., nutrients and dissolved oxygen) caused by seasonal hydrological dynamics. The particle-associated niche (PAN) index revealed that there were 94 non-conservative ARGs (i.e., no preferences for PA and FL), 23 conservative ARGs that preferred PA lifestyle, and 16 conservative ARGs for FL lifestyle. A sharp decline in the number of conservative ARGs in stratified seasons suggests a hydrological dynamics-dependent transition of ARGs between two lifestyles. Remarkably, the conservative ARGs (in PA or FL lifestyle) were more closely related to bacterial OTUs in their preferred lifestyle compared to their counterpart lifestyle, suggesting a lifestyle-dependent ARG enrichment. Altogether, these findings enhance our understanding of the role of seasonal hydrological changes in the dissemination of ARGs in different size fractions in deep aquatic ecosystems.

ecology↗

bioRxiv2022

Identification of a small chemical as a lysosomal calcium mobilizer and characterization of its ability to inhibit autophagy and viral infection

We previously identified GADPH as one of the cyclic adenosine diphosphoribose (cADPR)s binding proteins and found that GADPH participates in cADPR-mediated Ca2+ release from ER via RyRs. Based on the simulated cADPR-GAPDH complex structure, we performed the structure-based drug screening, identified several small chemicals with high docking scores to cADPRs binding pocket in GAPDH, and showed that two of these compounds, C244 and C346, are potential cADPR antagonists. We further synthesized several analogs of C346, and found that its analog, G42, also mobilized Ca2+ release from lysosomes. G42 alkalized lysosomal pH, and inhibited autophagosome-lysosome fusion. Moreover, G42 markedly inhibited Zika virus (ZIKV, a flavivirus) or murine hepatitis virus (MHV, a {beta}-coronavirus) infections of host cells. These results suggest that G42 inhibits virus infection, likely by triggering lysosomal Ca2+ mobilization and inhibiting autophagy.

microbiology↗

bioRxiv2022

Membrane wetting, molding and reticulation by protein condensates

Cells compartmentalize their components in liquid-like condensates, which can be reconstituted in vitro. Although these condensates interact with membrane-bound organelles, the potential of membrane remodeling and the underlying mechanisms are not well understood. Here, we demonstrate that interactions between protein condensates (including hollow ones) and membranes can lead to remarkable morphological transformations and describe these with theory. Modulation of solution salinity or membrane composition drives the condensate-membrane system through two wetting transitions, from dewetting, through a broad regime of partial wetting, to complete wetting. A new phenomenon, namely fingering or ruffling of the condensate-membrane interface is observed when sufficient membrane area is available, producing intricately curved structures. The observed morphologies are governed by the interplay of adhesion, membrane elasticity, and interfacial tension. Our results highlight the relevance of wetting in cell biology, and pave the way for the design of synthetic membrane-droplet based biomaterials and compartments with tunable properties.

biophysics↗

bioRxiv2022

Insulin receptors in pancreatic acinar cells contribute to KrasG12D-driven cancer initiation in the context of diet-induced obesity

The rising pancreatic cancer incidence due to obesity and type 2 diabetes is closely tied to hyperinsulinemia, an independent cancer risk factor. Previous studies demonstrated reducing insulin production suppressed pancreatic intraepithelial neoplasia (PanIN) pre-cancerous lesions in Kras-mutant mice. However, the pathophysiological and molecular mechanisms remained unknown and in particular it was unclear whether hyperinsulinemia affected PanIN precursor cells directly or indirectly. Here, we demonstrate that insulin receptors (Insr) in KrasG12D-expressing pancreatic acinar cells are dispensable for glucose homeostasis, but necessary for hyperinsulinemia-driven PanIN formation in the context of diet-induced hyperinsulinemia and obesity. Mechanistically, this was attributed to amplified digestive enzyme protein translation, triggering of local inflammation and PanIN metaplasia in vivo. In vitro, insulin dose-dependently increased acinar-to-ductal metaplasia formation in a trypsin- and Insr-dependent manner. Collectively, our data shed light on the mechanisms connecting obesity-driven hyperinsulinemia and pancreatic cancer development.

cancer biology↗

bioRxiv2022

Local translation provides the asymmetric distribution of CaMKII required for associative memory formation

How compartment-specific local proteomes are generated and maintained is inadequately understood, particularly in neurons, which display extreme asymmetries. Here we show that local enrichment of Ca2+/calmodulin-dependent protein kinase II (CaMKII) in axons of Drosophila mushroom body neurons is necessary for cellular plasticity and associative memory formation. Enrichment is achieved via enhanced axoplasmic translation of CaMKII mRNA, through a mechanism requiring the RNA-binding protein Mub and a 23-base Mub-recognition element in the CaMKII 3UTR. Perturbation of either dramatically reduces axonal, but not somatic, CaMKII protein without altering the distribution or amount of mRNA in vivo and both are necessary and sufficient to enhance axonal translation of reporter mRNA. Together, these data identify elevated levels of translation of an evenly distributed mRNA as a novel strategy for generating subcellular biochemical asymmetries. They further demonstrate the importance of distributional asymmetry in the computational and biological functions of neurons.

neuroscience↗

bioRxiv2022

PPML-Omics: a Privacy-Preserving federated Machine Learning system protects patients' privacy from omic data

Modern machine learning models towards various tasks with omic data analysis give rise to threats of privacy leakage of patients involved in those datasets. Despite the advances in different privacy technologies, existing methods tend to introduce too much computational cost (e.g. cryptographic methods) or noise (e.g. differential privacy), which hampers either model usefulness or accuracy in protecting privacy in biological data. Here, we proposed a secure and privacy-preserving machine learning method (PPML-Omics) by designing a decentralized version of the differential private federated learning algorithm. We applied PPML-Omics to analyze data from three sequencing technologies, and addressed the privacy concern in three major tasks of omic data, namely cancer classification with bulk RNA-seq, clustering with single-cell RNA-seq, and the integration of spatial gene expression and tumour morphology with spatial transcriptomics, under three representative deep learning models. We also examined privacy breaches in depth through privacy attack experiments and demonstrated that PPML-Omics could protect patients privacy. In each of these applications, PPML-Omics was able to outperform methods of comparison under the same level of privacy guarantee, demonstrating the versatility of the method in simultaneously balancing the privacy-preserving capability and utility in practical omic data analysis. Furthermore, we gave the theoretical proof of the privacy-preserving capability of PPML-Omics, suggesting the first mathematically guaranteed method with robust and generalizable empirical performance in protecting patients privacy in omic data.

bioinformatics↗

bioRxiv2022

Chromatin-associated lncRNA Malat1 regulates Th17 effector program and promotes intestinal inflammation

Interleukin IL-17 cytokines are central regulators of mucosal homeostasis and disease. In mouse models of colonic tissue injury, IL-17A promotes epithelial barrier functions and restricts local inflammation. Here, we report that IL-17A production by the diverse T lymphocyte subsets is dynamically regulated at different stages of colitis pathogenesis. During the onset and peak of the disease, T{gamma}{delta}17 cells are the major IL-17A producers, while Th17 activity is temporally restricted by long non-coding RNA (lncRNA) Malat1. In response to IL-6 and TGF{beta} signaling, Malat1 is recruited to the Th17-specific cis-regulatory elements, CNS3 and CNS4, of the Il17a locus to fine-tune bivalent super-enhancer activities and repress local transcription. During the resolution phase of inflammation, Malat1 expression is down-regulated to enhance Th17 activities, allowing Th17 cells to emerge as the main producers of IL-17A in the colonic lamina propria. Genetic ablation of Malat1 potentiates IL-17A production in Th17 cells and improves disease outcomes in mouse models of colitis. These findings uncover a surprising role of a chromatin-associated lncRNA in regulating colonic Th17-specific responses to control the timing of inflammation resolution. Significance StatementT cells are critical modulators of mucosal barrier function and inflammation. The function of long-noncoding RNAs (lncRNAs) in T cells and their role in mucosal inflammation remain elusive. Here, we identify an essential role of the lncRNA Malat1 restricting transcription of the Il17a locus in Th17 cells encoding a cytokine implicated in epithelial barrier function post-injury. By controlling the activity of the bivalent super-enhancer at the Il17a locus, Malat1 regulates the timing of inflammation resolution in the intestine. The Malat1-Il17a pathway reveals new targets for combating mucosal diseases. Graphic Abstract O_FIG_DISPLAY_L [Figure 1] M_FIG_DISPLAY C_FIG_DISPLAY

immunology↗

bioRxiv2022

Visual Perception of 3D Space and Shape In Time - Part IV: 3D Shape Recognition by 3D Rotation

Human vision has a remarkable ability to recognize complex 3D objects such as faces that appear at any size and 3D orientations at any 3D location. If we initially memorize a face only with a normalized size upfront at the object center, the direct comparison between the one-sized memory and an incoming new image would demand tremendous mental frame translations in 7D. How can we perform such a demanding task so promptly as we experience it in our daily lives? This paper specifically addresses the recognition of human faces with arbitrary 3D orientation in the [Roll, Yaw, Pitch] axes. According to our new model of NHT (Neural Holography Tomography), space is represented by time utilizing the phase of the alpha brainwave. This principle should be applicable to any mental rotation in 3D; thus, it predicts that extra time is required to perceive a rotated face to revolve it back to upright by the constant-speed alpha wave. To assess this hypothesis, we designed a reaction time (RT) experiment, where participants were first asked to memorize sets of upright unfamiliar faces. Following the memorization phase, similar stimuli with a wide range of rotating faces in 3D were presented, and RTs were recorded. As expected, the memorized upfront face was the fastest RT. The excess of the RT was observed proportional to the rotating angle in all [Roll, Yaw, Pitch] axes. Roll had the flattest slope, whereas upper Pitch was the steepest. We suspect that Roll is the swiftest mental operation because it can be conducted by the linear frame translation on the log-polar retinotopy of the visual cortex.

neuroscience↗

bioRxiv2022

The structure of insulin granule core determines secretory capacity being reduced in type-2 diabetes

Exocytosis in excitable cells is essential for their physiological functions. Although the exocytotic machinery controlling cellular secretion has been well investigated, the function of the vesicular cargo, i.e. secretory granular content remains obscure. Here we combine dSTORM imaging and single-domain insulin antibody, to dissect the in situ structure of insulin granule cores (IGCs) at nano level. We demonstrate that the size and shape of the IGCs can be regulated by the juxta-granular molecules Nucleobindin-2 and Enolase-1, that further contribute to the stimulated insulin secretion. IGCs located at the plasma membrane are larger than those in the cytosol. The IGCs size is decreased by [~]20% after glucose stimulation due to the release of the peripheral part of IGCs through incomplete granule fusion. Importantly, the reduction of the IGCs size is also observed in non-stimulatory pancreatic {beta}-cells from diabetic db/db mice, Akita (Ins2+/-) mice and human Type-2 diabetic donors, in accordance with impaired secretion. These findings overall highlight the structure of exocytotic insulin cores as a novel modality amenable to targeting in the stimulated exocytosis in {beta}-cells with impaired insulin secretion.

physiology↗

bioRxiv2022

Fate tracing reveals differences between Reelin+ HSCs and Desmin+ HSCs in activation, migration, and proliferation activities

The activation of hepatic stellate cells (HSCs) which comprise distinct clusters, is the main cause of liver fibrogenesis in response to different etiologies of chronic liver injuries. In this study, we constructed a novel ReelinCreERT2 transgenic mouse in which cells expressing Reelin were fully marked and demonstrated that about 50% HSCs were labeled. These ReelinCreERT2-labeled HSCs displayed distinct characteristics in migration, activation and proliferation compared to Desmin+ HSCs (total HSCs) in cholestatic (bile duct ligation; BDL) or hepatotoxic (carbon tetrachloride; CCl4) liver injuries. In BDL-induced fibrotic livers, Desmin+ HSCs were activated with increased proliferation and accumulation activities around the portal triad, but mGFP+ HSCs did not show proliferation or accumulation activity around the portal triad, and only a small part was activated. In CCl4-induced fibrotic livers, most of Desmin+ and mGFP+ HSCs were activated along with proliferation and accumulation potential around the central vein, however fewer mGFP+ HSCs were activated compared to Desmin+ HSCs. Moreover, in the regression of CCl4-induced fibrosis, mGFP+ HSCs were apoptosed whereas Desmin+ HSCs recovered to normal state. Besides, we didnt find evidence that mGFP+ HSCs transdifferentiated into hepatocytes or cholangiocytes through mesenchymal-epithelial transition (MET).

pathology↗

bioRxiv2022

Pairing-dependent plasticity in a dissected fly brain is input-specific and requires synaptic CaMKII enrichment and nighttime sleep

In Drosophila, in vivo functional imaging studies revealed that associative memory formation is coupled to a cascade of neural plasticity events in distinct compartments of the mushroom body (MB). In-depth investigation of the circuit dynamics, however, will require an ex vivo model that faithfully mirrors these events to allow direct manipulations of circuit elements that are inaccessible in the intact fly. The current ex vivo models have been able to reproduce the fundamental plasticity of aversive short-term memory, a potentiation of the MB intrinsic neurons (Kenyon cells; KCs) responses after artificial learning ex vivo. However, this potentiation showed different localization and encoding properties from those reported in vivo and failed to generate the previously reported suppression plasticity in the mushroom body output neurons (MBONs). Here, we develop an ex vivo model using the female Drosophila brain that recapitulates behaviorally evoked plasticity in the KCs and MBONs. We demonstrate that this plasticity accurately localizes to the MB 3 compartment and is encoded by a coincidence between KCs activation and dopaminergic input. The formed plasticity is input-specific, requiring pairing of the conditioned stimulus (CS) and unconditioned stimulus (US) pathways; hence we name it pairing-dependent plasticity (PDP). PDP formation requires an intact CaMKII gene and is blocked by previous-night sleep deprivation but is rescued by rebound sleep. In conclusion, we show that our ex vivo preparation recapitulates behavioral and imaging results from intact animals and can provide new insights into mechanisms of memory formation at the level of molecules, circuits, and brain state. Significance StatementThe mammalian ex vivo LTP model enabled in-depth investigation of the hippocampal memory circuit. We develop a parallel model to study the Drosophila mushroom body (MB) memory circuit. Pairing activation of the conditioned stimulus and unconditioned stimulus pathways in dissected brains induces a potentiation pairing-dependent plasticity (PDP) in the axons of {beta} Kenyon cells and a suppression PDP in the dendrites of their postsynaptic MB output neurons, localized in the MB 3 compartment. This PDP is input-specific and requires the 3 untranslated region of CaMKII. Interestingly, ex vivo PDP carries information about the animals experience before dissection; brains from sleep deprived animals fail to form PDP while those from animals who recovered 2 hours of their lost sleep form PDP.

neuroscience↗

bioRxiv2021

Genome assembly of the JD17 soybean provides a new reference genome for Comparative genomics

Cultivated soybean (Glycine max) is an important source for protein and oil. Many elite cultivars with different traits have been developed for different conditions. Each soybean strain has its own genetic diversity, and the availability of more high-quality soybean genomes can enhance comparative genomic analysis for identifying genetic underpinnings for its unique traits. In this study, we constructed a high-quality de novo assembly of an elite soybean cultivar Jidou 17 (JD17) with chromsome contiguity and high accuracy. We annotated 52,840 gene models and reconstructed 74,054 high-quality full-length transcripts. We performed a genome-wide comparative analysis based on the reference genome of JD17 with three published soybeans (WM82, ZH13 and W05), which identified five large inversions and two large translocations specific to JD17, 20,984 - 46,912 PAVs spanning 13.1 - 46.9 Mb in size, and 5 - 53 large PAV clusters larger than 500kb. 1,695,741 - 3,664,629 SNPs and 446,689 - 800,489 Indels were identified and annotated between JD17 and them. Symbiotic nitrogen fixation (SNF) genes were identified and the effects from these variants were further evaluated. It was found that the coding sequences of 9 nitrogen fixation-related genes were greatly affected. The high-quality genome assembly of JD17 can serve as a valuable reference for soybean functional genomics research.

genomics↗

bioRxiv2021

Allele frequency dynamics under sex-biased demography and sex-specific inheritance in a pedigreed population

Sex-biased demography, including sex-biased survival or migration, can alter allele frequency changes across the genome. In particular, we can expect different patterns of genetic variation on autosomes and sex chromosomes due to sex-specific differences in life histories, as well as differences in effective population size, transmission modes, and the strength and mode of selection. Here, we demonstrate the role that sex differences in life history played in shaping short-term evolutionary dynamics across the genome. We used a 25-year pedigree and genomic dataset from a long-studied population of Florida Scrub-Jays (Aphelocoma coerulescens) to directly characterize the relative roles of sex-biased demography and inheritance in shaping genome-wide allele frequency trajectories. We used gene dropping simulations to estimate individual genetic contributions to future generations and to model drift and immigration on the known pedigree. We quantified differential expected genetic contributions of males and females over time, showing the impact of sex-biased dispersal in a monogamous system. Due to female-biased dispersal, more autosomal variation is introduced by female immigrants. However, due to male-biased transmission, more Z variation is introduced by male immigrants. Finally, we partitioned the proportion of variance in allele frequency change through time due to male and female contributions. Overall, most allele frequency change is due to variance in survival and births. Males and females make similar contributions to autosomal allele frequency change, but males make higher contributions to allele frequency change on the Z chromosome. Our work shows the importance of understanding sex-specific demographic processes in characterizing genome-wide allele frequency change in wild populations.

evolutionary biology↗

bioRxiv2021

Inhibition of adrenergic b1-AR/Gas signaling promotes cardiomyocyte proliferation through activation of RhoA-YAP axis

The regeneration potential of the mammalian heart is incredibly limited, as cardiomyocyte proliferation ceases shortly after birth. {beta}-adrenergic receptor ({beta}-AR) blockade has been shown to improve heart functions in response to injury; however, the underlying mechanisms remain poorly understood. Here we inhibited {beta}-AR signaling in the heart using a cardiomyocyte specific {beta}1-adrenergic receptor ({beta}1-AR) blocker (metoprolol) to examine its role in heart maturation and regeneration at the neonatal stage. We found that metoprolol robustly enhanced cardiomyocyte proliferation and promoted cardiac regeneration post myocardial infarction, resulting in reduced scar formation and improved cardiac function. Moreover, the increased cardiomyocyte proliferation was also induced by the genetic deletion of Gnas, the gene encoding G protein alpha subunit (Gs), a downstream effector of {beta}-AR. Genome wide transcriptome analysis revealed that the cardiomyocytes of {beta}-blocker treated and Gnas cKO hearts maintained an immature proliferating status even at the young-adult age, and that the loss of Gs function enhanced the activity of the Hippo-effector YAP, which is associated with immature cardiomyocyte proliferation. Moreover, the increased YAP activity is modulated by RhoA signaling. Our pharmacological and genetic studies reveal a previously unrecognized {beta}1-AR-Gs-YAP signaling axis for regulating cardiac regeneration. These results suggest that inhibiting {beta}-AR-Gs signaling promotes the regenerative capacity and extends the cardiac regenerative window in mice by activating YAP-mediated transcriptional programs. Thus, targeting {beta}-AR-Gs signaling may serve as a novel therapeutic target for the treatment of ischemic heart.

developmental biology↗

bioRxiv2021

The rs1421085 variant within FTO promotes but not inhibits thermogenesis and is potentially associated with human migration

Disease-associated GWAS loci are predominantly scattered among noncoding regions of the human genome, which impedes causality estimation. One lead risk signal of obesity-rs1421085 T>C within the FTO gene-is reported to functional in vitro but lack of organismal evidence. Here, we established global and the brown-adipocyte specific locus-knock-in mice to recapitulate this homologous variant in humans, and discovered the minor allele (C-allele) as one candidate thermogenic locus. Mice carrying the C-alleles showed increased thermogenic capacity and a resistance to high-fat diet-induced adiposity. In terms of mechanism, the knock-in models showed enhanced FTO expression, while FTO knockdown or inhibition effectively eliminated the increased thermogenic ability of brown adipocytes. In humans, the C-allele was associated with lower birthweight, and its allele frequency increases following the environmental temperature decreases. Cumulatively, these findings demonstrated rs1421085 T>C as a functional variant regulating whole-body thermogenesis, and this variation was possibly related to early human migration from hot to cold environments.

genetics↗

bioRxiv2021

Correlational networking guides the discovery of cryptic proteases for lanthipeptide maturation

Bacterial natural product biosynthetic genes, canonically clustered, have been increasingly found to rely on cryptic enzymes encoded elsewhere in the genome for completion of biosynthesis. The study and application of lanthipeptides are frequently hindered by cryptic proteases required for final maturation. Here, we establish a global correlation network bridging the gap between lanthipeptide precursors and cryptic proteases. Applying our analysis to 161,954 bacterial genomes, we establish 5,209 correlations between precursors and cryptic proteases, with 91 prioritized. We use network predictions and co-expression analysis to reveal a previously missing protease for the maturation of class I lanthipeptide paenilan. We further discover widely distributed bacterial M16B metallopeptidases of previously unclear biological function as a new family of lanthipeptide proteases. We show the involvement of a pair of bifunctional M16B proteases in the production of novel class III lanthipeptides with high substrate specificity. Together, these results demonstrate the strength of our correlational networking approach to the discovery of cryptic lanthipeptide proteases and potentially other missing enzymes for natural products biosynthesis. Graphical abstract O_FIG_DISPLAY_L [Figure 1] M_FIG_DISPLAY C_FIG_DISPLAY

biochemistry↗

bioRxiv2021

African swine fever virus structural protein p17 inhibits cGAS-STING signaling pathway through interacting with STING

African swine fever (ASF) is highly contagious, causes high mortality in domestic and feral swine, and has a significant economic impact on the global swine industry due to the lack of a vaccine or an effective treatment. African swine fever virus (ASFV) encodes more than 150 polypeptides, which may have intricate and delicate interactions with the host for the benefit of the virus to evade the hosts defenses. However, currently, there is still a lack of information regarding the roles of the viral proteins in host cells. Here, our data demonstrated that the p17, encoded by D117L gene could suppress porcine cGAS-STING signaling pathway, exhibiting the inhibitions of TBK1 and IRF3 phosphorylations, downstream promoter activities, cellular mRNA transcriptions and ISG56 induction, and antiviral responses. Further, we found that p17 was located in endoplasmic reticulum (ER) and Golgi apparatus, and interacted with STING, perturbing it in the recruitment of TBK1 and IKK{varepsilon}. Additionally, it appeared that the transmembrane domain (amino acids 39-59) of p17 could be required for interacting with STING and inhibiting cGAS-STING pathway. Taken together, p17 could inhibit the cGAS-STING pathway through its interaction with STING and interference with STING in the recruitment of TBK1 and IKK{varepsilon}. ImportanceAfrican swine fever (ASF) is a highly contagious disease in domestic and feral swine, posing significant economic impacts on the global swine industry, and the pathogen ASFV is a large icosahedral DNA virus. The innate immune cGAS-STING DNA sensing pathway plays a critical role in sensing invading ASFV and triggering antiviral responses. However, there is still a lack of information regarding the molecular mechanisms of ASFV evasion of the cGAS-STING pathway. We have analyzed the effects of whole genomic open reading frames (ORFs) of ASFV China 2018/1 on the activation of cGAS-STING pathway, and found that p17 was able to inhibit cGAS-STING mediated type I IFN production by targeting STING, altering its capacity to recruit both TBK1 and IKK{varepsilon}. Findings presented here will expand our knowledge on the molecular mechanisms by which ASFV counteracts the antiviral innate immunity and provide deep insights into ASF pathogenesis.

immunology↗

bioRxiv2021

The African swine fever virus protease pS273R inhibits DNA sensing cGAS-STING pathway by targeting IKKε

African swine fever virus (ASFV), a large and complex cytoplasmic double-stranded DNA virus, has developed multiple strategies to evade the antiviral innate immune responses. Cytosolic DNA arising from invading ASFV is mainly detected by the cyclic GMP-AMP synthase (cGAS) and then triggers a series of innate immune responses to prevent virus invasion. However, the immune escape mechanism of ASFV remains to be fully clarified. The pS273R of ASFV is a member of the SUMO-1-specific protease family and is crucial for valid virus replication. In this study, we identified pS273R as a suppressor of cGAS-STING pathway mediated type I interferon (IFN) production by ASFV genomic open reading frame screening. The pS273R was further confirmed as an inhibitor of IFN production as well as its downstream antiviral genes in cGAS-STING pathway. Mechanistically, pS273R greatly decreased the cGAS-STING signaling by targeting IKK{varepsilon} but not TBK1 and pS273R was found to disturb the interaction between IKK{varepsilon} and STING through its interaction with IKK{varepsilon}. Further, mutational analyses revealed that pS273R antagonized the cGAS-STING pathway by enzyme catalytic activity, which may affect the IKK{varepsilon} sumoylation state required for the interaction with STING. In summary, our results revealed for the first time that pS273R acts as an obvious negative regulator of cGAS-STING pathway by targeting IKK{varepsilon} via its enzymatic activity, which shows a new immune evasion mechanism of ASFV. ImportanceAfrican swine fever (ASF) is a devastating disease for domestic pigs and wild boar and the pathogen ASFV is a cytoplasmic double-stranded DNA virus. The innate immune cGAS-STING-IFN signaling pathway exerts a critical role in sensing ASFV infection. However, the functions of half ASFV encoded 150 plus proteins are still unknown and the evasion against the cGAS-STING pathway is not resolved. In our study, via ASFV genomic open reading frame (ORF) screening, we found that 29 ASFV proteins could inhibit cGAS-STING signaling pathway, with pS273R showing the most obvious inhibitory effect. Surprisingly, pS273R was found to antagonize the cGAS-STING signaling by targeting IKK{varepsilon}. Moreover, the pS273R enzyme activity is required for its ability to inhibit the cGAS-STING pathway. Our findings deepen the understanding of the immune evasion mechanism of ASFV, which will provide a support for the development of safe and effective ASFV vaccines.

immunology↗