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Biology subjects

Yang, F.

Publications and source records attributed to Yang, F..

At least 145 records · Page 8Linked to original sources

Cultivation of host-adapted Cryptosporidium parvum and Cryptosporidium hominis using enteroids for cryopreservation of isolates and transcriptomic studies of infection

Cryptosporidium hominis and Cryptosporidium parvum are major causes of severe diarrhea in humans. Comparative studies of them are hampered by the lack of effective cultivation and cryopreservation methods, especially for C. hominis. Here, we described adapted murine enteroids for the cultivation of one C. parvum IId subtype and nonhuman primate-adapted C. hominis Ib, Im, and In subtypes, which allowed the complete development of the pathogens, producing oocysts infectious to mice. Using the system, we developed a novel cryopreservation method for Cryptosporidium isolates. In comparative RNA-seq analyses of C. hominis cultures, the enteroid system generated significantly more transcriptomic responses of both pathogen and host genes than the conventional HCT-8 cell system. In particular, the infection was shown to upregulate PI3K-Akt, Wnt, Ras,TNF, NF-{kappa}B, IL-17, MAPK, and innate immunity signaling pathways and downregulate Wnt and Hippo signaling pathways, host cell metabolism, and parasites in enteroid cultures had significantly higher expression of genes involved in oocyst formation. Therefore, the new culture model provides a valuable tool for comparative studies of the biology of divergent Cryptosporidium species. IMPORTANCE The two dominant species for human cryptosporidiosis, Cryptosporidium hominis and Cryptosporidium parvum, differ significantly in host range and virulence. Up to date, biological studies of Cryptosporidium spp. are almost exclusively done with bovine-adapted IIa subtypes of C. parvum, which is the species with effective laboratory animal models and in vitro cultivation methods. Here, we describe modified procedures for the generation of murine enteroids for successful cultivation of both nonhuman primate-adapted C. hominis subtypes and a C. parvum IId subtype, producing oocysts infective to mice. In addition, we have developed a novel cryopreservation method using the system for long-term storage of Cryptosporidium isolates. RNA-seq analyses of C. hominis cultures indicate that the enteroid culture system generates host and pathogen transcriptomic responses similar to those in natural infection. This new development alleviates a technical bottleneck in cryptosporidiosis research, and provides an example for other difficult-to-culture pathogens of major public health importance.

microbiology↗

The Lateral Ganglionic Eminence Does Not Generate Cortical Oligodendrocytes

The emergence of myelinating oligodendrocytes represents a pivotal developmental milestone in vertebrates, given their capacity to ensheath axons and facilitate the swift conduction of action potentials. It is widely accepted that cortical oligodendrocyte progenitor cells (OPCs) arise from medial ganglionic eminence (MGE), lateral/caudal ganglionic eminence (LGE/CGE) and cortical radial glial cells (RGCs). Here, we used two different fate mapping strategies to challenge the established notion that the LGE generates cortical OPCs. Furthermore, we used a Cre/loxP-dependent exclusion strategy to reveal that the LGE/CGE-derived OPCs are minimal. Additionally, we showed that specifically eliminating MGE-derived OPCs leads to a significant reduction of cortical OPCs. Together, our findings indicate that the contribution of OPCs from LGE/CGE is minimal, contrary to previous beliefs. These findings provide a new view of the developmental origins of cortical OPCs and a valuable foundation for future research on both normal development and oligodendrocyte-related disease.

developmental biology↗

CpG Island Definition and Methylation Mapping of the T2T-YAO Genome

Precisely defining and mapping all cytosine positions and their clusters, known as CpG islands (CGIs), as well as their methylation status are pivotal for genome-wide epigenetic studies, especially when population-centric reference genomes are ready for timely application. Here we first align the two high-quality reference genomes, T2T-YAO and T2T-CHM13, from different ethnic backgrounds in a base-by-base fashion and compute their genome-wide density-defined and position-defined CGIs. Second, mapping some representative genome-wide methylation data from selected organs onto the two genomes, we find that there are about 4.7-5.8% sequence divergency of variable categories depending on quality cutoffs. Genes among the divergent sequences are mostly associated with neurological functions. Moreover, CGIs associated with the divergent sequences are significantly different with respect to CpG density and observed CpG/expected CpG (O/E) ratio between the two genomes. Finally, we find that the T2T-YAO genome not only has a greater CpG site coverage than that of the T2T-CHM13 genome when whole-genome bisulfite sequencing (WGBS) data from the European and American populations are mapped to each reference, but also show more hyper-methylated CpG sites as compared to the T2T-CHM13 genome. Our study suggests that future genome-wide epigenetic studies of the Chinese populations rely on both acquisition of high-quality methylation data and subsequent precision CGI mapping based on the Chinese T2T reference.

bioinformatics↗

CSTA: A Biomarker Regulating Esophageal Stricture Epithelial Barrier, Potential Medication Target

Esophageal strictures resulting from ESD/EMR in the esophagus are distressing, with uncertain causes and treatments due to epithelial barrier dysfunction. We explored cystatin A (CSTA) as a novel biomarker for the esophageal epithelial barrier. CSTA regulates the barrier and is influenced by tacrolimus (FK506). Analyzing biopsy samples by proteomics, we identified CSTA as an esophageal epithelial biomarker. Knocking down CSTA reduced responsiveness to triamcinolone acetonide (TA) and lowered expression of proteins related to cell-cell junctions and barrier function during inflammation. These findings suggest that down-regulate CSTA weakens tight junctions and the esophageal barrier, leading to strictures. Notably, FK506 showed promise in rescuing CSTA-knockdown cells by increasing the expression of proteins related to cell-cell junctions and barrier function. This highlights FK506 as a potential therapy for esophageal strictures in patients with CSTA mutations.

cell biology↗

A peptide-centric local stability assay to unveil protein targets of diverse ligands

While tremendous progress has been made in chemical proteomics for identifying protein-ligand interactions, it remains challenging for proteome-wide identification of ligand-binding regions without modifying the ligands. Here, we discovered that "disruptive trypsinization" amplifies the readout of ligand-induced protein local stability shifts, and explored this notion in developing "peptide-centric local stability assay" (PELSA), a modification-free approach which achieves unprecedented sensitivity in proteome-wide target identification and binding-region determination. We demonstrate the versatility of PELSA by investigating the interactions across various biological contexts including drug-target interactions, metabolism, epitope mapping, metal proteomics, and post-translational modification recognition. A PELSA study of the oncometabolite R2HG revealed functional insights about its targets and pathogenic processes in both cancer and immune cells. Thus, beyond offering users unprecedented sensitivity for characterizing diverse target-ligand interactions, PELSA supports informative screening and hypothesis generation studies throughout life science.

biochemistry↗

Leaf δ13C reveals post-photosynthetic fractionation during ontogeny in a C4 grass

The 13C isotope composition ({delta}13C) of leaf dry matter is a useful tool for physiological and ecological studies. However, how post-photosynthetic fractionation associated with respiration and carbon export influences {delta}13C remains uncertain. We investigated the effects of post-photosynthetic fractionation on {delta}13C of mature leaves of Cleistogenes squarrosa, a perennial C4 grass, in controlled experiments with different levels of vapour pressure deficit and nitrogen supply. With the increase of leaf age classes, the 12C/13C fractionation of leaf organic matter relative to the {delta}13C of atmosphere CO2 ({Delta}DM) increased while that of cellulose ({Delta}cel) was almost constant. The divergence between {Delta}DM and {Delta}cel increased with leaf age classes with a maximum value of 1.6{per thousand}, indicating the accumulation post-photosynthetic fractionation. Applying a new mass balance model that accounts for respiration and export of photosynthates, we found an apparent 12C/13C fractionation associated with carbon export of -0.5 to -1.0{per thousand}. Different {Delta}DM among leaves, pseudostems, daughter tillers and roots indicate that post-photosynthetic fractionation happens at the whole-plant level. Compared with {Delta}DM of old leaves, {Delta}DM of young leaves and {Delta}cel are more reliable proxies for predicting physiological parameters due to the smaller sensitivity to post-photosynthetic fractionation and the similar sensitivity in responses to environmental changes. BRIEF SUMMARY STATEMENT{Delta}13C of bulk organic matter increases with leaf age classes while {Delta}13C of cellulose remain constant, lending support to the use of {Delta}13C of cellulose as a more reliable proxy for predicting physiological parameters due to the smaller sensitivity to post-photosynthetic fractionation.

plant biology↗

TRIP13 localizes to synapsed chromosomes and functions as a dosage-sensitive regulator of meiosis

Meiotic progression requires coordinated assembly and disassembly of protein complexes involved in chromosome synapsis and meiotic recombination. The AAA+ ATPase TRIP13 and its orthologue Pch2 are instrumental in remodeling HORMA domain proteins. Meiosis-specific HORMAD proteins are associated with unsynapsed chromosome axes but depleted from the synaptonemal complex (SC) of synapsed chromosome homologues. Here we report that TRIP13 localizes to the synapsed SC in early pachytene spermatocytes and to telomeres throughout meiotic prophase I. Loss of TRIP13 leads to meiotic arrest and thus sterility in both sexes. Trip13-null meiocytes exhibit abnormal persistence of HORMAD1 and HOMRAD2 on synapsed SC and chromosome asynapsis that preferentially affects XY and centromeric ends. These findings confirm the previously reported phenotypes of the Trip13 hypomorph alleles. Trip13 heterozygous (Trip13+/-) mice also exhibit meiotic defects that are less severe than the Trip13-null mice, showing that TRIP13 is a dosage-sensitive regulator of meiosis. Localization of TRIP13 to the synapsed SC is independent of SC axial element proteins such as REC8 and SYCP2/SYCP3. The N- or C-terminal FLAG-tagged TRIP13 proteins are functional and recapitulate the localization of native TRIP13 to SC and telomeres in knockin mice. Therefore, the evolutionarily conserved localization of TRIP13/Pch2 to the synapsed chromosomes provides an explanation for dissociation of HORMA domain proteins upon chromosome synapsis in diverse organisms.

cell biology↗

Exploring the mechanisms and potential therapeutic targets of Ferroptosis Related Genes in ankylosing spondylitis

BackgroundFerroptosis is a novel type of regulated cell death, and there is growing evidence that it is directly associated with the disease. Therefore, this study aimed to investigate the relevance of iron Ferroptosis-related genes to ankylosing spondylitis (AS) to propose a novel targeted therapy for AS patients. MethodsAS samples were downloaded from the Gene Expression Omnibus (GEO) database (GSE41038). Ferroptosis-related genes were obtained from the FerrDb database, and differential expression analysis was performed using the GEO2R tool. Additionally, we constructed a protein-protein interaction (PPI) network and identified the central genes using Cytoscape. A neural network model was developed utilizing the data mining software Clementine. cMap technology was used to screen potential pharmacological compounds that target the central gene,and a predictive model was built by machine learning methods. ResultsWe discovered 786 differentially expressed genes in AS samples compared to normal tissue, including 359 up-regulated and 427 down-regulated genes. The intersection of ferroptosis-related genes and differential genes yielded 20 overlapping genes. We constructed a hub gene co-expression network with 20 nodes and 14 edges and obtained the ten most recommended drugs for AS. ConclusionBioinformatics analysis identified 20 potential genes associated with Ferroptosis in AS. Genes such as CAV1, NOX4, and NQO1 were revealed to influence the development of AS by regulating Ferroptosis. Our study provides new insights into the function of iron Ferroptosis-related genes in AS, suggesting that targeting Ferroptosis may be a potential therapeutic option for AS.

bioinformatics↗

Metabolomics-assisted mechanism analysis of gamma-PGA synthesis regulated by PhoP in B. licheniformis

Poly {gamma}-glutamic acid ({gamma}-PGA) is a widely used biopolymer whose synthesis relies on external nitrogen sources. PhoP is a global transcription factor that has been reported to be involved in regulation of phosphorus and nitrogen metabolisms, whether PhoP regulates {gamma}-PGA synthesis is worthy of further study. In this study, {gamma}-PGA yield was decreased by 19.4% in phoP deletion strain, while PhoP overexpression benefited {gamma}-PGA synthesis in Bacillus licheniformis, and the results of transcriptional level, electrophoretic mobility shift (EMSA) and GFP expression assays confirmed the direct positive regulation on {gamma}-PGA synthetase gene pgsB by PhoP. Furthermore, based on metabolomic and physiological analysis, we dissected three aspects that {gamma}-PGA synthesis indirectly regulated by PhoP. (i) PhoP influences glutamate transport through positively regulating glutamate transporter GltT. (ii) PhoP influences nitrogen source utilization through negatively regulating nitrogen metabolic repressor TnrA and positively regulating GlnR. (iii) PhoP influences ammonia assimilation through GlnR and TnrA. Together, our study improved metabolic regulatory network of {gamma}-PGA synthesis, and laid a foundation for PhoP regulation nitrogen metabolic network in Bacillus.

microbiology↗

Characterization of N-glycosylation and its Functional Role in SIDT1-Mediated RNA Uptake

The mammalian SID-1 transmembrane family members, SIDT1 and SIDT2, are multi-pass transmembrane proteins that mediate the cellular uptake and intracellular trafficking of nucleic acids, playing important roles in the immune response and tumorigenesis. Previous work has suggested that human SIDT1 and SIDT2 are N-glycosylated, but the precise site-specific N-glycosylation information and its functional contribution remain unclear. In this study, we employ high-resolution liquid chromatography tandem mass spectrometry to comprehensively map the N-glycosites and quantify the N-glycosylation profiles of SIDT1 and SIDT2. Further molecular mechanistic probing elucidates the essential role of N-linked glycans in regulating cell surface expression, RNA binding, protein stability, and RNA uptake of SIDT1. Our results provide crucial information about the potential functional impact of N-glycosylation in the regulation of SIDT1-mediated RNA uptake and provide insights into the molecular mechanisms of this promising nucleic acid delivery system, with potential implications for therapeutic applications.

biochemistry↗

ISMI-VAE: A Deep Learning Model for Classifying Disease Cells Using Gene Expression and SNV Data

Various studies have linked several diseases, including cancer and Covid-19, to single nucleotide variations (SNV). Although scRNA-seq technology can provide SNV and gene expression data, few studies have integrated and analyzed these multimodal data. To address this issue, this paper introduces Interpretable Single-cell Multimodal Data Integration Based on Variational Autoencoder (ISMI-VAE). ISMI-VAE leverages latent variable models that utilize the characteristics of SNV and gene expression data to overcome high noise levels, and uses deep learning techniques to integrate multimodal information, map them to a low-dimensional space, and classify disease cells. Moreover, ISMI-VAE introduces an attention mechanism to reflect feature importance and analyze genetic features that could potentially cause disease. Experimental results on three cancer data sets and one Covid-19 data set demonstrate that ISMI-VAE surpasses the baseline method in terms of both effectiveness and interpretability, and can effectively identify disease-causing gene features.

bioinformatics↗

Atypical Biological Motion Perception in Children with Attention Deficit Hyperactivity Disorder: Dissociating the Roles of Local Motion and Global Configuration Processing

Perceiving biological motion (BM) is crucial for human survival and social interaction. Many studies have reported impaired BM perception in autism spectrum disorder, which is characterised by deficits in social interaction. Children with attention deficit hyperactivity disorder (ADHD) often exhibit similar difficulties in social interaction. However, few studies have investigated BM perception in children with ADHD. Here, we compared differences in the ability to process local kinematic and global configurational cues, two fundamental abilities of BM perception, between typically developing and ADHD children. We further investigated the relationship between BM perception and social interaction skills measured using the Social Responsiveness Scale and examined the contributions of latent factors (e.g., sex, age, attention, and intelligence) to BM perception. The results revealed that children with ADHD exhibited atypical BM perception. Local and global BM processing showed distinct features. Local BM processing ability was related to social interaction skills, whereas global BM processing ability significantly improved with age. Critically, general BM perception (i.e., both local and global BM processing) may be affected by sustained attentional ability in children with ADHD. This relationship was primarily mediated by reasoning intelligence. These findings elucidate atypical BM perception in ADHD and the latent factors related to BM perception. Moreover, this study provides new evidence that BM perception is a hallmark of social cognition and advances our understanding of the potential roles of local and global processing in BM perception and social cognitive disorders.

neuroscience↗

T2T-YAO: a Telomere-to-telomere Assembled Diploid Reference Genome for Han Chinese

Since its initial release in 2001, the human reference genome has been continuously improved in both continuity and accuracy, and the recently-released telomere-to-telomere version--T2T-CHM13--reaches its top quality after 20 years of effort. However, T2T-CHM13 does not represent an authentic diploid human genome, but rather one derived from a simplified, nearly homozygous genome of a hydatidiform mole cell line. To address this limitation and provide an alternative pertinent to the Chinese population, the largest ethnic group in the world, we have assembled a complete diploid human genome of a male Han Chinese, T2T-YAO, which includes telomere-to-telomere assemblies for all the 22+X+M and 22+Y chromosomes in his two haploids inherited separately from his parents. Both haplotypes contain no artificial sequences or model nucleotides and possess a high quality comparable to CHM13, with fewer than one error per [~]14 Mb. Derived from the individual who lives in the aboriginal region of Han Chinese, T2T-YAO shows clear ancestry and potential genetic continuity from the ancient ancestors of the Han population. Each haplotype of T2T-YAO possesses [~]340 Mb exclusive sequences and [~]3100 unique genes as compared to CHM13, and their genome sequences show greater genetic distance to CHM13 than to each other in terms of nucleotide polymorphism and structural variations. The construction of T2T-YAO would serve as a high-quality diploid reference that enables precise delineation of genomic variations in a haplotype-sensitive manner, which could advance our understandings in human evolution, hereditability of diseases and phenotypes, especially within the context of the unique variations of the Chinese population.

genetics↗

Quantifying Amide-Aromatic Interactions at Molecular and Atomic Levels: Experimentally-determined Enthalpic and Entropic Contributions to Interactions of Amide sp2O, N, C and sp3C Unified Atoms with Naphthalene sp2C Atoms in Water

In addition to amide hydrogen bonds and the hydrophobic effect, interactions involving {pi}-bonded sp2 atoms of amides, aromatics and other groups occur in protein self-assembly processes including folding, oligomerization and condensate formation. These interactions also occur in aqueous solutions of amide and aromatic compounds, where they can be quantified. Previous analysis of thermodynamic coefficients quantifying net-favorable interactions of amide compounds with other amides and aromatics revealed that interactions of amide sp2O with amide sp2N unified atoms (presumably C=O{middle dot}{middle dot}{middle dot}H-N hydrogen bonds) and amide/aromatic sp2C (lone pair-{pi}, n-{pi}*) are particularly favorable. Sp3C-sp3C (hydrophobic), sp3C-sp2C (hydrophobic, CH-{pi}), sp2C-sp2C (hydrophobic, {pi}-{pi}) and sp3C-sp2N interactions are favorable, sp2C-sp2N interactions are neutral, while sp2O-sp2O and sp2N-sp2N self-interactions and sp2O-sp3C interactions are unfavorable. Here, from determinations of favorable effects of fourteen amides on naphthalene solubility at 10, 25 and 45 {degrees}C, we dissect amide-aromatic interaction free energies into enthalpic and entropic contributions and find these vary systematically with amide composition. Analysis of these results yields enthalpic and entropic contributions to intrinsic strengths of interactions of amide sp2O, sp2N, sp2C and sp3C unified atoms with aromatic sp2C atoms. For each interaction, enthalpic and entropic contributions have the same sign and are much larger in magnitude than the interaction free energy itself. The amide sp2O-aromatic sp2C interaction is enthalpy-driven and entropically unfavorable, consistent with direct chemical interaction (e.g. lone pair-{pi}) while amide sp3C- and sp2C-aromatic sp2C interactions are entropy-driven and enthalpically unfavorable, consistent with hydrophobic effects. These findings are relevant for interactions involving {pi}-bonded sp2 atoms in protein processes. Table of Contents Graphic O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=109 SRC="FIGDIR/small/548600v2_ufig1.gif" ALT="Figure 1"> View larger version (36K): org.highwire.dtl.DTLVardef@1683bb4org.highwire.dtl.DTLVardef@27db75org.highwire.dtl.DTLVardef@b915ccorg.highwire.dtl.DTLVardef@1461b04_HPS_FORMAT_FIGEXP M_FIG C_FIG

biochemistry↗

A temperature-sensitive metabolic valve and a transcriptional feedback loop drive rapid homeoviscous adaptation in Escherichia coli

All free-living microorganisms homeostatically maintain the fluidity of their membranes by adapting lipid composition to environmental temperatures. A quantitative description of how organisms maintain constant fluidity at all growth temperatures has not been achieved. By quantifying both enzymes and metabolic intermediates of the Escherichia coli fatty acid and phospholipid synthesis pathways, we discover how E. coli measures steady-state temperature and restores optimal membrane fluidity within a single generation after temperature shocks. The first element of the system is a temperature-sensitive metabolic valve that allocates flux between the saturated and unsaturated fatty acid synthesis pathways. The second element is a transcription-based negative feedback loop that counteracts the temperature-sensitive valve. The combination of these elements accelerates membrane adaptation by causing a transient overshoot in the synthesis of saturated or unsaturated fatty acids following temperature shocks. This overshoot strategy accelerates membrane adaptation, and is comparable to increasing the temperature of a water bath by adding water that is excessively hot rather than adding water at the desired temperature. These properties are captured in a quantitative model, which we further use to show how hard-wired parameters calibrate the system to generate membrane compositions that maintain constant fluidity across a wide range of temperatures. We hypothesize that core design features of the E. coli system will prove to be ubiquitous features of homeoviscous adaptation systems.

microbiology↗

Reduced binding associated with resistance to Vip3Aa in the corn earworm (Helicoverpa zea)

Transgenic corn and cotton expressing Cry and Vip insecticidal proteins from the bacterium, Bacillus thuringiensis (Bt), have been a valuable tool for the management of lepidopteran pests. In 2019, a Vip3Aa-resistant strain of Helicoverpa zea (CEW-Vip-RR) was isolated from F2 screens of field populations in Texas. Characterizing the resistance mechanism in this strain is important for predicting the sustained efficacy of current commercial Bt traits and guiding the development of future transgenic traits. Resistance to insecticidal proteins in Bt traits is commonly associated with reduced toxin binding, with the exception of Vip3Aa resistance being associated to altered proteolytic processing in the insect host gut. Therefore, Vip3Aa protoxin processing was tested by incubation with midgut fluids from CEW-Vip-RR relative to a susceptible strain (CEW-SS). Finding no significant processing differences, alterations in Vip3Aa binding were tested by comparing binding of radiolabeled and biotinylated Vip3Aa toxin to midgut brush border membrane vesicles (BBMV) from CEW-Vip-RR and CEW-SS larvae. Specific Vip3Aa binding to CEW-Vip-RR BBMV in these experiments was consistently reduced when compared with CEW-SS BBMV. These results support that an altered Vip3Aa- receptor is associated with resistance in CEW-Vip-RR. Understanding this resistance mechanism could have important implications for resistance management decisions considering widespread Cry1 and Cry2 resistance in H. zea populations. IMPORTANCEHelicoverpa zea is a major crop pest in the United States that is managed with transgenic corn and cotton producing insecticidal proteins from the bacterium, Bacillus thuringiensis (Bt). However, H. zea has evolved widespread resistance to the Cry proteins produced in Bt corn and cotton, leaving Vip3Aa as the only plant incorporated protectant in Bt crops consistently providing excellent control of H. zea. The benefits provided by Bt crops will be substantially reduced if widespread Vip3Aa resistance develops in H. zea field populations. Therefore, it is important to identify resistance alleles and mechanisms that contribute to Vip3Aa resistance to ensure that informed resistance management strategies are implemented. This study is the first report of reduced binding of Vip3Aa to midgut receptors associated with resistance.

pathology↗

A pre-trained large language model for translating single-cell transcriptome to proteome

Proteins are crucial for life, and measuring their abundance at the single-cell level can facilitate a high-resolution understanding of biological mechanisms in cellular processes and disease progression. However, current single-cell proteomic technologies face challenges such as limited coverage, throughput, and sensitivity, as well as batch effects, high costs, and stringent experimental operations. Drawing inspiration from the translation procedure of both natural language processing (NLP) and the genetic central dogma, we propose a pre-trained, large generative model named scTranslator (single-cell translator). scTranslator is align-free and capable of generating multi-omics data by inferring the missing single-cell proteome based on the transcriptome. Systematic benchmarking confirms the accuracy, stability, and flexibility of scTranslator across various quantification techniques, cell types, and conditions. Furthermore, scTranslator has demonstrated its superiority in assisting various downstream analyses and applications, including gene/protein interaction inference, gene pseudo-knockout, cell clustering, batch correction, and cell origin recognition on pan-cancer data.

bioinformatics↗

A pseudovirus-based method to dynamically mimic SARS-CoV-2-associated cell-to-cell fusion and transmission

SARS-CoV-2 has caused the global tremendous loss and continues to evolve to generate variants. Entry of SARS-CoV-2 into the host cells is primarily mediated by Spike (S), which binds to the host receptor hACE2 and initiates virus-cell membrane fusion. Cell fusion contributes to viral entry, cell-to-cell transmission and tissue damage in COVID-19 patients. Many reporter assays have been developed to study S-mediated cell fusion by equally coculturing S-expressing cells and hACE2-positive cells. However, these strategies cannot fully simulate cell-to-cell fusion and transmission of SARS-CoV-2 infection, in which virions from a single target cell transmit to the neighbor cells and induce syncytia formation. Here, we design a pseudovirus-based method to dynamically mimic cell-to-cell fusion and transmission of SARS-CoV-2. We coculture a small number of pseudovirus-producing 293FT cells and a large number of hACE2-expressing 293T cells, and demonstrate that a single cell producing S-pseudotyped virions can induce significant syncytia of hACE2-positive cells. This pseudovirus-based method is a powerful tool to screen and estimate potential inhibitors of S-driven syncytia. Moreover, this strategy can also be utilized to explore fusogenic ability of SARS-CoV-2 variants. Together, the pseudovirus-based method we report here will be beneficial to drug screening and scientific research against SARS-CoV-2 or future emerging coronavirus.

microbiology↗