Biology subjects

Feng, J.

Publications and source records attributed to Feng, J..

At least 181 records · Page 10Linked to original sources

bioRxiv2022

Hypoxia Dynamically Regulates DBC1 Ubiquitination and Stability by SIAH2 and OTUD5 in Breast Cancer Progression

DBC1 has been characterized as a key regulator of physiological and pathophysiological activities, such as DNA damage, senescence and tumorigenesis. However, the mechanism by which the functional stability of DBC1 is regulated has yet to be elucidated. Here, we report that the ubiquitination-mediated degradation of DBC1 is dynamically regulated by the E3 ubiquitin ligase SIAH2 and deubiquitinase OTUD5 under hypoxic stress. Mechanistically, hypoxia promoted the competitive binding of SIAH2 with OTUD5 to DBC1, resulting in the ubiquitination and subsequent degradation of DBC1 through the ubiquitin-proteasome pathway. Siah2 knockout inhibited tumor cell proliferation and migration, which could be rescued by double knockout of Siah2/DBC1. Human tissue microarray analysis further revealed that the SIAH2/DBC1 axis was responsible for tumor progression under hypoxic stress. These findings define a key role of the hypoxia-mediated SIAH2-DBC1 pathway in the progression of human breast cancer and provide novel insights into the metastatic mechanism of breast cancer.

cell biology↗

bioRxiv2021

Connectome-wide association analysis identified significant brain functional alteration in adults with attention-deficit/hyperactivity disorder

Adults with attention-deficit/hyperactivity disorder (ADHD), as an extreme-phenotype of ADHD, is still facing problems of inconsistency and undeciphered mechanisms for its neuropathology. To address this matter, our present study performed connecotome-wide voxel-based analyses with the resting-state fMRI data of 84 adults with ADHD and 89 healthy controls. We found that functional connectivity patterns of the left precuneus and the left middle temporal significantly altered in ADHD populations serving as potential neural biomarkers to distinguish ADHD with healthy controls, with subsequent seed-based analysis revealing the dysfunction of functional connections both intra- and inter-default mode and attention networks, among which middle temporal gyrus plays the key role of bridge linking the default mode and attention networks. After cognitive behavioral therapy, two of these ADHD-altered functional connections ameliorated accompanied with improvement of ADHD core symptoms. Additionally, imaging genetic analyses also revealed close relationships between the observed brain functional alterations and ADHD-risk genes. Taken together, our findings suggested the interference of default mode on attention networks in adults with ADHD, which would be severing as a potential biomarker for both ADHD pathogenesis and treatment effects.

neuroscience↗

bioRxiv2021

solPredict: Antibody apparent solubility prediction from sequence by transfer learning

There is growing interest in developing therapeutic mAbs for the route of subcutaneous administration for several reasons, including patient convenience and compliance. This requires identifying mAbs with superior solubility that are amenable for high-concentration formulation development. However, early selection of developable antibodies with optimal high-concentration attributes remains challenging. Since experimental screening is often material and labor intensive, there is significant interest in developing robust in silico tools capable of screening thousands of molecules based on sequence information alone. In this paper, we present a strategy applying protein language modeling, named solPredict, to predict the apparent solubility of mAbs in histidine (pH 6.0) buffer condition. solPredict inputs embeddings extracted from pretrained protein language model from single sequences into a shallow neutral network. A dataset of 220 diverse, in-house mAbs, with extrapolated protein solubility data obtained from PEG-induced precipitation method, were used for model training and hyperparameter tuning through five-fold cross validation. An independent test set of 40 mAbs were used for model evaluation. solPredict achieves high correlation with experimental data (Spearman correlation coefficient = 0.86, Pearson correlation coefficient = 0.84, R2 = 0.69, and RMSE = 4.40). The output from solPredict directly corresponds to experimental solubility measurements (PEG %) and enables quantitative interpretation of results. This approach eliminates the need of 3D structure modeling of mAbs, descriptor computation, and expert-crafted input features. The minimal computational expense of solPredict enables rapid, large-scale, and high-throughput screening of mAbs during early antibody discovery.

bioinformatics↗

bioRxiv2021

Divergence and convergence of cortical encoding during word reading in bilinguals

Word reading includes a series of cognitive processes that convert low-level visual characteristics to neural representations. However, the consistency of the neural mechanisms for processing these cognitive components across different writing systems in bilinguals remains inconclusive. Here, we explored this question by employing representational similarity analysis with a semantic access task involving Chinese words, English words and Chinese pinyin. Distinct anatomical distribution patterns were detected for each type of brain representation across ideographic and alphabetic languages, resulting in 100% classification accuracy. Meanwhile, convergent cognitive components processing was found in the core language-related regions in left hemisphere, including the inferior frontal gyrus, temporal pole, superior and middle temporal gyrus, precentral gyrus and supplementary motor areas. Broadly, our findings indicated that the neural basis for word recognition of different writing systems in bilinguals was divergent in anatomical locations of neural representations for specialized processing but convergent in cognitive domains, which supported and enriched the assimilation-accommodation hypothesis. TeaserCortical encoding linguistic processing across languages was support by parallel interdigitated distributed networks but convergent in cognitive domains.

neuroscience↗

bioRxiv2021

Clonal hematopoiesis in individuals with ANKRD26 or ETV6 germline mutations

Currently, there are at least a dozen recognized hereditary hematopoietic malignancies (HHMs), some of which phenocopy others. Among these, three HHMs driven by germline mutations in ANKRD26, ETV6, or RUNX1 share a phenotype of thrombocytopenia, qualitative platelet defects, and an increased lifetime risk of hematopoietic malignancies (HMs). Prior work has demonstrated that RUNX1 germline mutation carriers experience an elevated lifetime risk (66%) for developing clonal hematopoiesis (CH) prior to age 50. Germline mutations in ANKRD26 or ETV6 phenocopy RUNX1 germline mutations, but no studies have focused on the risk of CH in individuals with germline mutations in ANKRD26 or ETV6. To determine the prevalence of CH in individuals with germline mutations in ANKRD26 or ETV6, we performed next generation sequencing on hematopoietic tissue from twelve individuals with either germline ANKRD26 or germline ETV6 mutations. Each patient had thrombocytopenia but had not developed HMs. Among the seven individuals with germline ANKRD26 mutations, one patient had a CH clone driven by a somatic SF3B1 mutation (p.Lys700Glu). This mutation increased from a variant allele frequency (VAF) of 9.4% at age 56 to 17.4% at age 60. None of the germline ETV6 mutation carriers had evidence of CH at the limits of detection of the NGS assay (5% VAF). Unlike individuals with germline mutations in RUNX1, no individuals under the age of 50 with germline mutations in ANKRD26 or ETV6 had detectable CH. This work demonstrates that ANKRD26 germline mutation carriers, but not ETV6 mutation carriers, experience elevated risk for CH.

genetics↗

bioRxiv2021

SC2MeNetDrug: A computational tool to uncover inter-cell signaling targets and identify relevant drugs based on single cell RNA-seq data

Single-cell RNA sequencing (scRNA-seq) is a powerful technology to investigate the transcriptional programs in stromal, immune, and disease cells, like tumor cells or neurons within the Alzheimers Disease (AD) brain or tumor microenvironment (ME) or niche. Cell-cell communications within ME play important roles in disease progression and immunotherapy response and are novel and critical therapeutic targets. Though many tools of scRNA-seq analysis have been developed to investigate the heterogeneity and sub-populations of cells, few were designed for uncovering cell-cell communications of ME and predicting the potentially effective drugs to inhibit the communications. Moreover, the data analysis processes of discovering signaling communication networks and effective drugs using scRNA-seq data are complex and involve a set of critical analysis processes and external supportive data resources, which are difficult for researchers who have no strong computational background and training in scRNA-seq data analysis. To address these challenges, in this study, we developed a novel open-source computational tool, sc2MeNetDrug (https://fuhaililab.github.io/sc2MeNetDrug/). It was specifically designed using scRNA-seq data to identify cell types within disease MEs, uncover the dysfunctional signaling pathways within individual cell types and interactions among different cell types, and predict effective drugs that can potentially disrupt cell-cell signaling communications. sc2MeNetDrug provided a user-friendly graphical user interface to encapsulate the data analysis modules, which can facilitate the scRNA-seq data-based discovery of novel inter-cell signaling communications and novel therapeutic regimens.

bioinformatics↗

bioRxiv2021

Structural basis of malaria transmission blockade by a monoclonal antibody to gamete fusogen HAP2

HAP2 is a transmembrane gamete fusogen found in multiple eukaryotic kingdoms and is structurally homologous to viral class II fusogens. Studies in Plasmodium have suggested that HAP2 is an attractive target for vaccines that block transmission of malaria. HAP2 has three extracellular domains, arranged in the order D2, D1, and D3. Here, we report monoclonal antibodies against the D3 fragment of Plasmodium berghei HAP2 and crystal structures of D3 in complex with Fab fragments of two of these antibodies, one of which blocks fertilization of Plasmodium berghei in vitro and transmission of malaria in mosquitos. We also show how this Fab binds the complete HAP2 ectodomain with electron microscopy. The two antibodies cross-react with HAP2 among multiple plasmodial species. Our characterization of the Plasmodium D3 structure, HAP2 ectodomain architecture, and mechanism of inhibition provide insights for the development of a vaccine to block malaria transmission.

immunology↗

bioRxiv2021

Kdm6b confers Tfdp1 with the competence to activate p53 signalling in regulating palatogenesis

Epigenetic regulation plays extensive roles in diseases and development. Disruption of epigenetic regulation not only increases the risk of cancer, but can also cause various developmental defects. However, it is still unclear how epigenetic regulators coordinate with tissue-specific regulatory factors during morphogenesis of specific organs. Using palatogenesis as a model, we reveal the functional significance of Kdm6b, a H3K27me3 demethylase, in regulating embryonic development. Our study shows that Kdm6b plays an essential role in neural crest development, and loss of Kdm6b disturbs p53 pathway-mediated activity, leading to complete cleft palate along with cell proliferation and differentiation defects. Furthermore, activity of H3K27me3 on the promoter of p53 is precisely controlled by Kdm6b, and Ezh2 in regulating p53 expression in cranial neural crest cells. More importantly, Kdm6b renders chromatin accessible to the transcription factor Tfdp1, which binds to the promoter of p53 along with Kdm6b to specifically activate p53 expression during palatogenesis. Collectively our results highlight the important role of the epigenetic regulator Kdm6b and how it cooperates with Tfdp1 to achieve its functional specificity in regulating p53 expression, and further provide mechanistic insights into the epigenetic regulatory network during organogenesis.

developmental biology↗

bioRxiv2021

The effects of age, sex, weight and breed on canid methylomes

Unlike genomes, which are static throughout the lifespan of an organism, DNA methylomes are dynamic. To study these dynamics we developed quantitative models that measure the effect of multiple factors on DNA methylomes including, age, sex, weight and genetics. We conducted our study in canids, which prove to be an ideal species to assess epigenetic moderators due to their extreme variability in size and well-characterized genetic structure. We collected buccal swabs from 217 canids (207 domestic dogs and 10 gray wolves) and used targeted bisulfite sequencing to measure methylomes. We also measured genotypes at over one thousand single nucleotide polymorphisms (SNPs). We found that DNA methylomes are strongly associated with age, enabling the construction of epigenetic clocks. We also show that methylomes are strongly impacted by sex, weight and sterilization status, leading to accurate predators of these factors. Methylomes are also affected by genetics and we observe multiple associations between SNP loci and methylated CpGs. Finally, we show that several factors moderate the relationship between epigenetic ages and real ages, such as body weight, which increases epigenetic aging. In conclusion, we demonstrate that the plasticity of DNA methylomes is impacted by myriad genetic and physiological factors, and that DNA methylation biomarkers are accurate predictors of age, sex and sterilization status.

bioinformatics↗

bioRxiv2021

The inflammatory accumulation of lipids and ROS in human Nrf1α-deficient hepatoma cells is ameliorated by 2-bromopalmitate

Since Nrf1 and Nrf2 are essential for regulating the lipid metabolism pathways, their dysregulation has thus been shown to be critically involved in the non-controllable inflammatory transformation into cancer. Herein, we have explored the molecular mechanisms underlying their distinct regulation of lipid metabolism, by comparatively analyzing the changes in those lipid metabolism-related genes in Nrf1-/- and/or Nrf2-/- cell lines relative to wild-type controls. The results revealed that loss of Nrf1 leads to lipid metabolism disorders. That is, its lipid synthesis pathway was up-regulated by the JNK-Nrf2-AP1 signaling, while its lipid decomposition pathway was down-regulated by the nuclear receptor PPAR-PGC1 signaling, thereby resulting in severe accumulation of lipids as deposited in lipid droplets. By contrast, knockout of Nrf2 gave rise to decreases in lipid synthesis and uptake capacity. These demonstrate that Nrf1 and Nrf2 contribute to significant differences in the cellular lipid metabolism profiles and relevant pathological responses. Further experimental evidence unraveled that lipid deposition in Nrf1-/- cells resulted from CD36 up-regulation by activating the PI3K-AKT-mTOR pathway, leading to abnormal activation of the inflammatory response. This was also accompanied by a series of adverse consequences, e.g., accumulation of reactive oxygen species (ROS) in Nrf1-/- cells. Interestingly, treatment of Nrf1-/- cells with 2-bromopalmitate (2BP) enabled the yield of lipid droplets to be strikingly alleviated, as accompanied by substantial abolishment of CD36 and critical inflammatory cytokines. Such Nrf1-/- led inflammatory accumulation of lipids, as well as ROS, was significantly ameliorated by 2BP. Overall, this study provides a potential strategy for cancer prevention and treatment by precision targeting of Nrf1, Nrf2 alone or both.

cancer biology↗

bioRxiv2021

Crotamiton derivative JM03 extends lifespan and improves oxidative and hypertonic stress resistance in Caenorhabditis elegans via inhibiting OSM-9

While screening our in-house 1,072 marketed drugs for their ability to extend the lifespan using Caenorhabditis elegans (C. elegans) as an animal model, crotamiton (N-ethyl-o-crotonotoluidide) showed anti-aging activity and was selected for further structural optimization. After replacing the ortho-methyl of crotamiton with ortho-fluoro, crotamiton derivative JM03 was obtained and showed better activity in terms of lifespan-extension and stress resistance than crotamiton. It was further explored that JM03 extended the lifespan of C. elegans through osmotic avoidance abnormal-9 (OSM-9). Besides, JM03 improves the ability of nematode to resist oxidative stress and hypertonic stress through OSM-9, but not osm-9/capsaicin receptor related-2 (OCR-2). Then the inhibition of OSM-9 by JM03 reduces the aggregation of Q35 in C. elegans via upregulating the genes associated with proteostasis. SKN-1 signaling was also found to be activated after JM03 treatment, which might contribute to proteostasis, stress resistance and lifespan extension. In summary, this study explored a new small molecule derived from crotamiton, which has efficient anti-oxidative, anti-hypertonic and anti-aging effects, and could further lead to promising application prospects.

cell biology↗

bioRxiv2021

A novel analytical decoder of BOLD signals for dissociating latent neurobehavioral processes

How to retrieve latent neurobehavioral processes from complex neurobiological signals is an important yet unresolved challenge. Here, we develop a novel approach, orthogonal-Decoding multi-Cognitive Processes (DeCoP), to reveal underlying latent neurobehavioral processing and show that its performance is superior to traditional non-orthogonal decoding in terms of both false inference and robustness. Processing value and salience information are two fundamental but mutually confounded pathways of reward reinforcement essential for decision making. During reward/punishment anticipation, we applied DeCoP to decode brain-wide responses into spatially overlapping, yet functionally independent, evaluation and readiness processes, which are modulated differentially by meso-limbic vs nigro-striatal dopamine systems. Using DeCoP, we further demonstrated that most brain regions only encoded abstract information but not the exact input, except for dACC and insula. Furthermore, our novel analytical principle could be applied generally to decode multiple latent neurobehavioral processes and thus advance both the design and hypothesis testing for cognitive tasks.

neuroscience↗

bioRxiv2021

Characterization of a vaccine-elicited human antibody with sequence homology to VRC01-class antibodies that binds the C1C2 gp120 domain

Broadly HIV-1 neutralizing VRC01-class antibodies bind the CD4-binding site of the HIV-1 envelope (Env) and contain VH1-2*02-derived heavy chains paired with light chains expressing five amino acid long CDRL3s. Their unmutated forms do not recognize Env or neutralize HIV-1. The lack of elicitation of VRC01-class antibodies in human clinical trials could potentially be due to the absence of activation of the corresponding naive B cells by the vaccine Env immunogens. To address this point directly, we examined Env-specific BCR sequences from participants in the HVTN 100 clinical trial. Of all the sequences analyzed only one displayed sequence homology to VRC01-class antibodies, but the corresponding antibody (FH1) recognized the C1C2 gp120 domain. For FH1 to switch epitope recognition to the CD4-binding site, alterations in both the CDRH3 and CDRL3 were necessary. Our findings support the use of specifically designed immunogens to activate VRC01-class B cells in future human vaccine trials.

immunology↗

bioRxiv2021

Brain Laterality Dynamics Support Human Cognition

Hemispheric lateralization constitutes a core architectural principle of human brain organization underlying cognition, often argued to represent a stable, trait-like feature. However, emerging evidence underlines the inherently dynamic nature of brain networks, in which time-resolved alterations in functional lateralization remain uncharted. Integrating dynamic network approaches with the concept of hemispheric laterality, we map the spatiotemporal architecture of whole-brain lateralization in a large sample of high-quality resting-state fMRI data (N=991, Human Connectome Project). We reveal distinct laterality dynamics across lower-order sensorimotor systems and higher-order associative networks. Specifically, we expose two aspects of the laterality dynamics: laterality fluctuations, defined as the standard deviation of laterality time series, and laterality reversal, referring to the number of zero-crossings in laterality time series. These two measures are associated with moderate and extreme changes in laterality over time, respectively. While laterality fluctuations depict positive association with language function and cognitive flexibility, laterality reversal shows a negative association with the same neurocognitive factors. These opposing interactions indicate a dynamic balance between intra- and inter-hemispheric communication, i.e., segregation and integration of information across hemispheres. Furthermore, in their time-resolved laterality index, the default-mode and language networks correlate negatively with visual/sensorimotor and attention networks, indicating flexible while parallel processing capabilities that are linked to better out-of-scanner cognitive performance. Finally, the laterality dynamics correlate with regional metabolism and structural connectivity and showed significant heritability. Our results provide insights into the adaptive nature of the lateralized brain and new perspectives for future studies of human cognition, genetics and brain disorders.

neuroscience↗

bioRxiv2021

TRPM2 deficiency protects against atherosclerosis by inhibiting TRPM2-CD36 inflammatory axis in macrophages

Atherosclerosis is the major cause of ischemic heart diseases and ischemic brain stroke, which are the leading causes of mortality worldwide. The central pathological features of atherosclerosis include macrophage infiltration and foam cell formation. However, the detailed mechanisms regulating these two processes remain unclear. Here we show that oxidative stress-activated Ca2+-permeable TRPM2 plays a key role in the pathogenesis of atherosclerosis. Trpm2 deletion produces a potent protective effect against atherosclerosis in ApoE-/- mice fed with a high-fat diet (HFD), as evidenced by reduced atherosclerotic plaque burden, decreased macrophage load and suppressed inflammasome activation in the vessel wall. Moreover, we show that Trpm2 deletion or inhibition reduces oxidized low-density lipoprotein (oxLDL) uptake by macrophages, suppresses macrophage infiltration induced by monocyte chemoattractant protein-1 (MCP1), and prevents the impairment of macrophage emigration caused by oxLDL. Intriguingly, we uncover that activation of CD36, an oxLDL receptor, can promote the activation of TRPM2, and vice versa, the CD36-mediated inflammatory cascade in atherosclerosis is dependent on TRPM2. In transfected HEK293T cells, CD36 ligands oxLDL and TSP1 induce TRPM2 activation in a CD36-dependent manner. Deleting Trpm2 or inhibiting TRPM2 activity in cultured macrophages suppresses the CD36 signaling cascade induced by oxLDL and TSP1. Our studies establish TRPM2-CD36 axis as a new mechanism underlying atherogenesis, and suggest TRPM2 as an effective therapeutic target for atherosclerosis. HIGHLIGHTSO_LITrpm2 deletion protects against atherosclerosis in ApoE-/- mice fed with a high-fat diet (HFD) C_LIO_LITrpm2 deficiency reduces atherosclerotic lesions by minimizing foam cell formation, inhibiting macrophage infiltration and preserving macrophage emigration C_LIO_LITRPM2 activation is required for CD36-induced oxLDL uptake and subsequent inflammatory responses C_LIO_LIThe ligands of CD36, oxLDL and TSP1, activate TRPM2, thereby perpetuating TRPM2-CD36 inflammatory cycle in atherogenesis cascade C_LIO_LIOur data establish TRPM2-CD36 axis as a new atherogenesis mechanism and TRPM2 as a novel therapeutic target for atherosclerosis C_LI O_FIG_DISPLAY_L [Figure 1] M_FIG_DISPLAY TRPM2-mediated Ca2+ signal is essential for CD36 induced oxLDL uptake and atherosclerosis in ApoE-/- mice fed with a high-fat diet (HFD). The activation of CD36 and TRPM2 form a positive feedback loop in atherogenesis. C_FIG_DISPLAY

physiology↗

bioRxiv2021

Functional coupling of TRPM2 and NMDARs exacerbates excitotoxicity in ischemic brain injury

Excitotoxicity caused by NMDA receptors (NMDARs) is a major cause of neuronal death in ischemic stroke. However, past efforts of directly targeting NMDARs have unfortunately failed in clinical ischemic stroke trials. Here we reveal an unexpected mechanism underlying NMDARs-mediated neurotoxicity, which leads to identification of a novel target and development of an effective therapeutic peptide for ischemic stroke. We show that NMDARs excitotoxicity upon ischemic insults is mediated by physical and functional coupling to TRPM2. The physical interaction of TRPM2 with NMDARs results in markedly increase in the surface expression of NMDARs, leading to enhanced NMDAR function and increased neuronal death. We identified a specific NMDAR-interacting domain on TRPM2, and developed a cell-permeable peptide to uncouple TRPM2-NMDARs. The disrupting-peptide protects neurons against ischemic injury in vitro and protects mice against ischemic stroke in vivo. These findings provide an unconventional strategy to eliminate excitotoxic neuronal death without directly targeting NMDARs. HIGHLIGHTSO_LITRPM2 physically and functionally interacts with NMDARs C_LIO_LIInteraction of TRPM2 with NMDARs exacerbates NMDARs extrasynaptic excitotoxicity by increasing NMDARs surface expression during ischemic injury C_LIO_LITRPM2 recruits PKC{gamma} to the interacting complexes to increase NMDARs surface expression C_LIO_LIUncoupling the interaction between TRPM2 and NMDARs with a disrupting peptide (TAT-EE3) protects neurons against ischemic stroke in vitro and in vivo C_LI GRAPHIC ABSTRACT O_FIG O_LINKSMALLFIG WIDTH=175 HEIGHT=200 SRC="FIGDIR/small/454247v1_ufig1.gif" ALT="Figure 1"> View larger version (53K): org.highwire.dtl.DTLVardef@e618c5org.highwire.dtl.DTLVardef@646350org.highwire.dtl.DTLVardef@b4478corg.highwire.dtl.DTLVardef@1c5742f_HPS_FORMAT_FIGEXP M_FIG C_FIG TRPM2 excerbates NMDARs excitotoxicity by physically and functionally interacting with NMDARs. The disrupting pipette TAT-EE3 protects neurons against ischemic injury in vitro and in vivo.

neuroscience↗

bioRxiv2021

Integration of the cyanophage-encoded phosphate binding protein into the cyanobacterial phosphate uptake system

To acquire phosphorus, cyanobacteria use the typical bacterial ABC-type phosphate transporter, which is composed of a periplasmic high-affinity phosphate-binding protein PstS and a channel formed by two transmembrane proteins PstC and PstA. The pstS gene has been identified in the genomes of cyanophages that infect the unicellular cyanobacteria Prochlorococcus and Synechococcus. However, it is unknown how the cyanophage PstS interplays with the host PstC and PstA to function as a chimeric ABC transporter. Here we showed that the cyanophage P-SSM2 PstS protein was abundant in the infected Prochlorococcus NATL2A cells and the host phosphate uptake rate was enhanced after infection. This is consistent with our biochemical and structural analyses showing that the phage PstS protein is indeed a high-affinity phosphate-binding protein. We further modeled the complex structure of phage PstS with host PstCA and revealed three putative interfaces that may facilitate the formation of the chimeric ABC transporter. Our results provide insights into the molecular mechanism by which cyanophages enhance the phosphate uptake rate of cyanobacteria. Phosphate acquisition by infected bacteria can increase the phosphorus contents of released cellular debris and virus particles, which together constitute a significant proportion of the marine dissolved organic phosphorus pool.

microbiology↗

bioRxiv2021

NSUN2-mediated m5C methylation of IRF3 mRNA negatively regulates type I interferon responses

5-Methylcytosine (m5C) is a widespread post-transcriptional RNA modification and is reported to be involved in manifold cellular responses and biological processes through regulating RNA metabolism. However, its regulatory role in antiviral innate immunity has not yet been elucidated. Here, we report that NSUN2, a typical m5C methyltransferase, can negatively regulate type I interferon responses during viral infection. NSUN2 specifically mediates m5C methylation of IRF3 mRNA and accelerates its degradation, resulting in low levels of IRF3 and downstream IFN-{beta} production. Knockout or knockdown of NSUN2 could enhance type I interferon responses and downstream ISG expression after viral infection in vitro. And in vivo, the antiviral innate responses is more dramatically enhanced in Nsun2+/- mice than in Nsun2+/+ mice. Four highly m5C methylated cytosines in IRF3 mRNA were identified, and their mutation could enhance the cellular IRF3 mRNA levels. Moreover, infection with Sendai virus (SeV), vesicular stomatitis virus (VSV), herpes simplex virus 1 (HSV-1), Zika virus (ZIKV), or especially SARS-CoV-2 resulted in a reduction in endogenous levels of NSUN2. Together, our findings reveal that NSUN2 serves as a negative regulator of interferon response by accelerating the fast turnover of IRF3 mRNA, while endogenous NSUN2 levels decrease after viral infection to boost antiviral responses for the effective elimination of viruses. Our results suggest a paradigm of innate antiviral immune responses ingeniously involving NSUN2-mediated m5C modification.

immunology↗