Biology subjects

Qian, Y.

Publications and source records attributed to Qian, Y..

At least 91 records · Page 5Linked to original sources

bioRxiv2022

Identification of S1PR4 as an immune modulator for favorable prognosis in HNSCC through unbiased machine learning

As the largest family of membrane proteins, G protein-coupled receptors (GPCRs) are the most prominent family of pharmacological targets. However, only a few GPCRs have been well-defined in terms of their physiological and pathological functions. Thus, an efficient way to identify key GPCRs involved in tumour formation is urgently needed. In this study, patients with head and neck squamous cell carcinoma (HNSCC) were classified into two different subtypes based on the characteristics of GPCRs using an unbiased machine learning method. Notably, these two subtypes showed significant differences in prognosis, gene expression, and immune microenvironment, especially in the infiltration of CD8+ T cells. Based on these differences, we screened three potential key regulators (S1PR4, S1PR5, and GPR87) from all GPCRs and constructed a prognostic nomogram for patients with HNSCC. We identified S1PR4 as the key GPCR in determining the two subtypes for positive correlation with the proportion and cytotoxicity of CD8+ T cells in HNSCC and was mainly expressed in a subset of CX3CR1+CD8+ T cells. We also demonstrated that S1PR4 is an immune modulator for the favourable prognosis of HNSCC patients. We found that S1PR4 was highly expressed in CD8+ T cells from the tumours of HNSCC patients, which was significantly associated with better prognosis, and S1PR4 expression was accompanied by higher T cell cytotoxic marker expression (IFNG and GZMB). Notably, S1PR4 co-localised with CX3CR1, which has been identified as the most cytotoxic marker of CD8+ T cells. Furthermore, S1PR4 upregulation could significantly increase T cell function in CAR-T cell therapy, indicating its great potential in cancer immunotherapy. Therefore, these results identified S1PR4 as a key indicator of cytotoxicity and the proportion of tumour-infiltrating CD8+ T cells and confirmed the prognostic value of S1PR4 in HNSCC. Our findings contribute to the knowledge of S1PR4 in anti-tumour immunity, providing a potential GPCR-targeted therapeutic option for future HNSCC treatment.

cancer biology↗

bioRxiv2022

Single-cell bacterial sequencing of invertible loci reveals promoter inversion rates as a strong determinant of population heterogeneity

Population heterogeneity can promote bacterial fitness in response to unpredictable environmental conditions. Human gut symbiont Bacteroides spp., displays variability in single cell surface architectures by combinatorial regulation of promoter inversions that drive expression of capsular polysaccharides (CPS). Using high-throughput single-cell sequencing, we reveal population heterogeneity generated through combinatorial promoter inversion and show that B. fragilis populations can access diverse CPS promoter states. Combining our data with stochastic computational modeling, we demonstrate that the rates of promoter inversion regulated by a broadly conserved serine recombinase are a major mechanism shaping population heterogeneity. Exploiting control over the expression of the recombinase, we devise a method for creating phase-locked variants and show that populations with different initial compositions converge to a similar steady-state composition over time. Our approach can be used to interrogate single-cell phase variable states of diverse microbes including bacterial pathogens. Summary sentenceHigh-throughput single cell sequencing of phase variation reveals regulation as a major driver of population diversification

systems biology↗

bioRxiv2022

Paradoxical tumor suppressive role of the musculoaponeurotic fibrosarcoma gene in colorectal cancer

Somatic cell reprogramming using the microRNAs miR200c, miR-302s, and miR-369s leads to increased expression of cyclin-dependent kinase inhibitors in human colorectal cancer (CRC) cells and suppressed tumor growth. Here, we investigated whether these microRNAs inhibit colorectal tumorigenesis in CPC;Apc mice, which are prone to colon and rectal polyps. Repeated administration of microRNAs inhibited polyp formation. Microarray analysis indicated that c-MAF, which reportedly shows oncogene-like behavior in multiple myeloma and T-cell lymphoma, decreased in tumor samples but increased in microRNA-treated normal mucosa. Immunohistochemistry identified downregulation of c-MAF as an early tumorigenesis event in CRC, with low c-MAF expression associated with poor prognosis. Of note, c-MAF expression and p53 protein levels were inversely correlated in CRC samples. c-MAF knockout led to enhanced tumor formation in azoxymethane/dextran sodium sulfate-treated mice, with activation of cancer-promoting genes. c-MAF may play a tumor-suppressive role in CRC development.

molecular biology↗

bioRxiv2022

Temporally multiplexed imaging of dynamic signaling networks in living cells

Molecular signals interact to mediate diverse biological computations. Ideally one would be able to image many signals at once, in the same living cell, to reveal how they work together. Here we report temporally multiplexed imaging (TMI), which uses the clocklike properties of fluorescent proteins to enable different cellular signals to be represented by different temporal fluorescence codes. Using different photoswitchable fluorescent proteins to represent different cellular signals, we can linearly decompose a brief movie of the fluorescence fluctuations in a given cell, into a sum of the fluctuation traces of each individual fluorophore, each weighted by its respective signal amplitude. We demonstrate the power of TMI to report relationships amongst a diversity of second messenger, kinase, and cell cycle signals, using ordinary microscopes. One-Sentence SummaryImaging of many dynamic signals in a living cell is possible by using distinct clocklike fluorophores to represent the activity of each signal.

molecular biology↗

bioRxiv2022

Programmable RNA Sensing for Cell Monitoring and Manipulation

RNAs are the central and universal mediator of genetic information underlying the diversity of cell types and cell states, which together shape tissue organization and organismal function across species and life spans. Despite advances in RNA sequencing and massive accumulation of transcriptome datasets across life sciences, the dearth of technologies that leverage RNAs to observe and manipulate cell types remains a prohibitive bottleneck in biology and medicine. Here, we describe CellREADR (Cell access through RNA sensing by Endogenous ADAR), a programmable RNA sensing technology that leverages RNA editing mediated by ADAR (adenosine deaminase acting on RNA) for coupling the detection of cell-defining RNAs with translation of effector proteins. Viral delivery of CellREADR conferred specific cell type access in mouse and rat brains and in ex vivo human brain tissues. Furthermore, CellREADR enabled recording and control of neuron types in behaving mice. CellREADR thus highlights the potential for RNA-based monitoring and editing of animal cells in ways that are specific, versatile, easy, and generalizable across organ systems and species, with broad applications in biology, biotechnology, and programmable RNA medicine.

molecular biology↗

bioRxiv2022

Multiple omic investigations of freeze tolerance adaptation in the aquatic ectothermic vertebrate, the Amur sleeper

Freeze tolerance is an amazing overwintering strategy that enables ectotherms to occupy new niches and survive in cold climates. However, the genetic basis underpinning this ecologically relevant adaptation is largely unknown. Amur sleeper is the only known freeze-tolerant fish species that can overwinter with its entire body frozen in ice. Here, we sequenced the chromosome-level genome of the Amur sleeper and performed comparative genomic, transcriptomic, and metabolomic analyses to investigate this remarkable adaptation. Phylogenetic analyses showed that the Amur sleeper diverged from its close relative with no cold hardiness about 15.07 million years ago and revealed two unusual population expansions during the glacial epochs. Integrative omics data identified a synchronous regulation of genes and metabolites involved in hypometabolism and cellular stress response, and several related genes showed strong evidence of accelerated evolution and positive selection. Potential evolutionary innovations that might aid in freezing survival were found to be associated with the dynamic rearrangement of the cytoskeleton to maintain cell viability, redistribution of water and cryoprotectants to limit cell volume reduction, and inhibition in nerve activity to facilitate dormancy, demonstrating a coordinated evolution for this complex adaptation. Overall, our work provides valuable resources and opportunities to unveil the genetic basis of freeze tolerance adaptation in ectothermic vertebrates.

evolutionary biology↗

bioRxiv2022

Growth limitation via chemically complex carbohydrates reduces sensitivity of synthetic human gut communities to perturbations

Dietary fiber affects the composition and functions of microbial communities that reside in the human gut. However, we lack a detailed and quantitative understanding of how these nutrients shape microbial community dynamics, interaction networks and systems-level properties. Using synthetic human gut communities coupled to computational modeling, we dissect the effects of varied fiber types or their constituent sugars on community assembly and sensitivity to perturbations. By quantifying carbohydrate chemical complexity, we demonstrate that microbial growth decreases as a function of complexity. We further demonstrate that the balance of species occupying distinct metabolic niches is altered by the presence of chemically complex carbohydrates. The frequency of negative inter-species interactions is reduced in the presence of complex carbohydrates. Communities grown in complex carbohydrates reproducibly assemble from a wide range of initial species abundances and display reduced sensitivity to invasion. Resource competition is identified as a key mechanism influencing the response of communities to perturbations. The strength of resource competition can promote sensitivity of community assembly to variations in initial species proportions and impact community resistance to invasion. By limiting microbial growth, complex carbohydrates promote the expansion of species occupying niches beyond carbohydrate utilization, shape the distribution of inter-species interactions, which in turn determines the communitys response to perturbations.

ecology↗

bioRxiv2022

Building molecular band-pass filters via molecular sequestration

Engineered genetic circuits with tailored functions that mimic how cells process information in changing environments (e.g. cell fate decision, chemotaxis, immune response) have great applications in biomedicine and synthetic biology. Although there is a lot of progress toward the design of gene circuits yielding desired steady states (e.g. logic-based networks), building synthetic circuits for dynamic signal processing (e.g. filters, frequency modulation, and controllers) is still challenging. Here, we provide a model-based approach to build gene networks that can operate as band-pass filters by taking advantage of molecular sequestration. By suitably approximating the dynamics of molecular sequestration, we analyze an Incoherent Feed-Forward Loop (IFFL) and a Negative Feedback (NF) circuit and illustrate how they can achieve band-pass filter behavior. Computational analysis shows that a circuit that incorporates both IFFL and NF motifs improves the filter performance. Our approach facilitates the design of sequestration-based filters, and may support the synthesis of molecular controllers with desired specifications.

synthetic biology↗

bioRxiv2022

An atypical ABC transporter is involved in antifungal resistance and host interactions in the pathogenic fungus Cryptococcus neoformans

ATP-binding cassette (ABC) transporters represent one of the largest protein superfamilies. Functionally diverse, ABC transporters have been implicated in many aspects of microbial physiology. The genome of the human fungal pathogen Cryptococcus neoformans encodes 54 putative ABC transporters and the majority of them remain uncharacterized. In a previous genetic screen for fungal regulators of phagocytosis, we identified an uncharacterized gene, CNAG_06909, that modulates host interactions. This gene encodes a half-size ABC transporter of the PDR-type, and phenotypic studies of a strain with this gene deleted revealed an altered antifungal susceptibility profile, including hypersensitivity to fluconazole (FLC). This gene, which we have named PDR6, localizes to the endoplasmic reticulum (ER) and plasma membrane (PM), and when absent, less ergosterol is observed in the PM. Additionally, we observed that the pdr6{Delta} strain displays a reduction in secreted polysaccharide capsular material. These changes to the cellular surface may explain the observed increased uptake by macrophages and the reduced intracellular survival. Finally, studies in mice demonstrate that Pdr6 function is required for normal progression of cryptococcal infection. Taken together, this study demonstrates a novel dual role for PDR transporters in C. neoformans, which could represent a potential target for antifungal therapeutics. Furthermore, the atypical half-size transporter encoded by PDR6 is conserved in many fungal pathogens, but absent in model non-pathogenic fungi. Hence, this study provides for the first time, a function for this unique group of fungal half-size PDR transporters that, although conserved, remain largely understudied. IMPORTANCEConserved across all kingdoms of life, ABC transporters comprise one of the largest protein families. They are associated with multidrug resistance, affecting aspects such as resistance to antimicrobials or anti-cancer drugs. Despite their importance, they are understudied in fungal pathogens. In the environmental fungus Cryptococcus neoformans, a leading cause of fungal infections, only a few ABC transporters have been studied. Here we characterize an atypical, half-size, ABC transporter of the PDR-type, that affects both antifungal resistance and host-pathogen interactions. PDR-type transporters are only present in fungi and plants, and this subgroup of half-size transporters is conserved in fungal pathogens, yet their function was completely unknown. Because the current treatments for cryptococcal infection are suboptimal, understanding the mechanisms of antifungal resistance and the host interactions that drive the infection is critical to improve the management of this disease. Here we provide insights into these important aspects of cryptococcal pathogenesis.

microbiology↗

bioRxiv2022

Simultaneously spatiotemporal gene expression and chromatin accessibility for mouse brain development

Brain are complex biological tissues which function relies on coordinated anatomical and molecular structure comprised by a large number of specialized cells. The spatial architecture of brain which is key to the understanding of its physiological and pathological significance is formed during embryo development. However, the molecular basis for discrete neuroanatomical domains particularly in the context of spatial organization of the brain is inadequate. Here, we introduced microfluidic indexing based spatial ATAC and RNA sequencing (MISAR-seq), a method for joint profiling of chromatin accessibility and gene expression with spatial information retained in the developing mouse brain. Our study has established a direct means to spatially determine the coordination between chromatin accessibility and transcriptome, identified the chromatin potential to define cell fate determination of brain organization, and uncovered spatiotemporal regulatory principles during mammalian brain development.

developmental biology↗

bioRxiv2021

E3 ligase TRIM47 positively regulates endothelial activation and pulmonary inflammation through potentiating the K63-linked ubiquitination

Endothelial activation plays an essential role in the pathology of sepsis-induced acute lung injury, but the detailed regulatory mechanisms remain largely unknown. Here, we demonstrated that TRIM47, an ubiquitin E3 ligase of tripartite protein family, is highly expressed in vascular endothelial cells and is up-regulated during TNF-induced endothelial activation. Knockdown of TRIM47 in endothelial cells prevents the transcription of multiple pro-inflammatory cytokines, reduces monocyte adhesion and the expression of adhesion molecules, and inhibits the secretion of IL-1{beta} and IL-6 into the supernatant. By contrast, overexpression of TRIM47 promotes inflammatory response and monocyte adhesion upon TNF stimulation. TRIM47 modulates the activation of NF-{kappa}B and MAPK signaling pathways during endothelial activation. Further experiment confirmed that TRIM47 interacts with TRAF2 and mediates K63-linked ubiquitination. In addition, TRIM47-deficient mice are more resistant to lipopolysaccharide-induced acute lung injury and death, due to attenuated pulmonary inflammation. Taken together, our studies suggest that TRIM47 promotes pulmonary inflammation and injury at least partly through potentiating the K63-linked ubiquitination of TRAF2, which in turn activates NF-{kappa}B and MAPK signaling pathways to trigger inflammatory response in endothelial cells.

cell biology↗

bioRxiv2021

ASFV pD345L protein negatively regulates NF-kB signaling through inhibiting IKK kinase activity

NF-{kappa}B is a critical transcription factor in immediate early viral infection, including African swine fever virus (ASFV), playing an important role in inflammation response and expression of antiviral genes. ASFV encodes for more than 151 proteins by its own transcription machinery and possesses a great capacity to evade or subvert antiviral innate immune responses. A couple of such viral proteins have been reported, but many remain unknown. Here, we showed that pD345L, an ASFV-encoded lambda-like exonuclease, is an inhibitor of cGAS/STING mediated NF-{kappa}B signaling by blocking IKK/{beta} kinase activity. Specifically, we showed that overexpression of pD345L suppresses cGAS/STING induced IFN{beta} and NF-{kappa}B activation, resulting in decreased transcription of IFN{beta} and several pro-inflammatory cytokines, including IL-1, IL-6, IL-8, and TNF. In addition, we showed that pD345L targeted at or downstream of IKK and upstream of p65. Importantly, we found that pD345L associates with KD and HLH domains of IKK and LZ domain of IKK{beta}, and thus interrupts their kinase activity on downstream substrate I{kappa}B. Finally, we showed that pD345L inhibition of NF-{kappa}B signaling was independent of its exonuclease activity. Taken together, we concluded that pD345L blocks IKK /{beta} kinase activity by protein-protein interaction and thus disrupts cGAS/STING mediated NF-{kappa}B signaling. ImportanceAfrican Swine Fever (ASF) is one of the most devastating and economically significant swine diseases caused by African swine fever virus (ASFV). Since expanding of ASFV affected areas into Asian countries, especially China, an effective vaccine is urgently needed more than ever. Therefore, it is of great significance to understand the interaction between ASFV infection and host immune responses. The NF-{kappa}B signaling plays a central role in innate and acquired immune responses. Activation of I{kappa}B kinase (IKK) complex is a key step of both canonical and non-canonical NF-{kappa}B pathways, and is commonly targeted by different viruses. But no ASFV protein has been shown to regulate IKK yet. In this study, we demonstrated that pD345L blocks IKK/{beta} kinase activity by protein-protein interaction and thus disrupts cGAS/STING mediated NF-{kappa}B signaling. It has been shown that conventional vaccine development approaches are proven to be inapplicable to ASFV. Neither subunit nor DNA vaccine provides efficient protection. Gene deleted live-attenuated vaccine candidates render adequate protection, but establishment of chronic or persistent infection in vaccinated animals and risk of recombination with filed strains are key challenges. To overcome these, one potential strategy would be generation of replication-defective viruses. As a lambda-like exonuclease, pD345L plays a critical role in ASFV replication and ASFV deficient in D345L cannot be rescued. Given the dual role of pD345L in virus replication and immune evasion, it may serve as a potential target for replication-defective virus vaccine development.

microbiology↗

bioRxiv2021

Polysaccharide utilization loci in Bacteroides determine population fitness and community-level interactions

Polysaccharide utilization loci (PULs) in the human gut microbiome have critical roles in shaping human health and ecological dynamics. We develop a CRISPR-FnCpf1-RecT genome-editing tool to study 23 PULs in the highly abundant species B. uniformis (BU). We identify the glycan-degrading functions of multiple PULs and elucidate transcriptional coordination between PULs that enables the population to adapt to the loss of PULs. Exploiting a pooled BU mutant barcoding strategy, we demonstrate that the in vitro fitness and the colonization ability of BU in the murine gut is enhanced by deletion of specific PULs and modulated by glycan availability. We show that BU PULs can mediate complex glycan-dependent interactions with butyrate producers that depend on the mechanism of degradation and the butyrate producer glycan utilizing ability. In sum, PULs are major determinants of community dynamics and butyrate production and can provide a selective advantage or disadvantage depending on the nutritional landscape.

synthetic biology↗

bioRxiv2021

Engineered AIM-based Selective Autophagy to Degrade Proteins and Organelles

Techniques for disrupting of protein function are essential for biological researches and therapeutics development. Though well-established, genetic perturbation strategies may have off-target effects and/or trigger compensatory mechanisms, and cannot efficiently eliminate existing protein variants or aggregates1, 2. Therefore, precise and direct protein-targeting methods are highly desired. Here we describe a novel method for targeted protein clearance by engineering an autophagy receptor with a binder to provide target specificity and an ATG8-binding motif (AIM) to link the targets to nascent autophagosomes, thus harnessing the autophagy machinery for degradation. We demonstrate its specificity and broad potentials by degrading various fluorescent-tagged proteins and peroxisome organelle, using a tobacco-based transient expression system, and by degrading endogenous proteins in transgenic Arabidopsis expressing engineered receptors. With the wide substrate scope and specificity of selective autophagy, our method provides a convenient and robust strategy for eliminating proteins and aggregates, and may enable developing new treatments for protein-related disorders.

cell biology↗

bioRxiv2021

Knocking-out the human face genes TBX15 and PAX1 in mice alters facial and other physical morphology

DNA variants in or closed to the human TBX15 and PAX1 genes have been repeatedly associated with facial morphology in independent genome-wide association studies, while their functional roles in determining facial morphology remains to be understood. We generated Tbx15 knockout (Tbx15-/-) and Pax1 knockout (Pax1-/-) mice by applying the one-step CRISPR/Cas9 method. A total of 75 adult mice were used for subsequent phenotype analysis, including 38 Tbx15 mice (10 homozygous Tbx15-/-, 18 heterozygous Tbx15+/-, 10 wild-type WT) and 37 Pax1 mice (12 homozygous Pax1-/-, 15 heterozygous Pax1+/-, 10 WT mice). Facial and other physical morphological phenotypes were obtained from three-dimensional (3D) images acquired with the HandySCAN BLACK scanner. Compared to WT mice, the Tbx15-/- mutant mice had significantly shorter faces (P=1.08E-8, R2=0.61) and their ears were in a significantly lower position (P=3.54E-8, R2=0.62) manifesting an "ear dropping" characteristic. Besides these face alternations, Tbx15-/- mutant mice displayed significantly lower weight as well as shorter body and limb length. Pax1-/- mutant mice showed significantly longer noses (P=1.14E-5, R2=0.46) relative to WT mice, but otherwise displayed less obvious morphological alterations than Tbx15-/- mutant mice did. Because the Tbx15 and Pax1 effects on facial morphology we revealed here in mice are largely consistent with previously reported TBX15 and PAX1 face associations in humans, we suggest that the functional role these two genes play on determining the face of mice is similar to the functional impact their human homologues have on the face of humans. Author SummarySeveral independent genome-wide association studies (GWASs) on human facial morphology highlighted DNA variants in or closed to TBX15 and PAX1 with genome-wide significant association with human facial phenotypes. However, direct evidence on the functional involvement if these genes in the development and determination of facial morphology has not been established as of yet. In the current study, our in vivo gene editing experiments in mice for two well-replicated human face TBX15 and PAX1 genes provide novel evidence on the functional involvement of these two genes in facial and other physical morphology in mice, at least. Tbx15-/- mice showed a shortened facial length and manifesting an ear dropping characteristic, Pax1-/- mice showed an increased nose length. Our geometric morphometrics analysis further indicate that there are significant facial morphology differences between groups (Tbx15-/-and Tbx15+/-, Tbx15-/- and Tbx15+/+, Tbx15+/- and Tbx15+/+, Pax1-/- and Pax1+/+). We provide the first direct functional evidence that two well-known and replicated human face genes, Tbx15 and Pax1, impact facial and other body morphology in mice. The general agreement between our findings in knock-out mice with those from previous GWASs suggests that the functional evidence we established here in mice may also be relevant in humans.

genetics↗

bioRxiv2021

Robust and tunable signal processing in mammalian cells via engineered covalent modification cycles

Rewired and synthetic signaling networks can impart cells with new functionalities and enable efforts in engineering cell therapies and directing cell development. However, there is a need for tools to build synthetic signaling networks that are tunable, can precisely regulate target gene expression, and are robust to perturbations within the complex context of mammalian cells. Here, we use proteins derived from bacterial two-component signaling pathways to develop synthetic phosphorylation-based and feedback-controlled devices in mammalian cells with such properties. First, we isolate kinase and phosphatase proteins from the bifunctional histidine kinase EnvZ. We then use these proteins to engineer a synthetic covalent modification cycle, in which the kinase and phosphatase competitively regulate phosphorylation of the cognate response regulator OmpR, enabling analog tuning of OmpR-driven gene expression. Further, we show that the phosphorylation cycle can be extended by connecting phosphatase expression to small molecule and miRNA inputs in the cell, with the latter enabling cell-type specific signaling responses and accurate cell type classification. Finally, we implement a tunable negative feedback controller by co-expressing the kinase-driven output gene with the small molecule-tunable phosphatase. This negative feedback substantially reduces cell-to-cell noise in output expression and mitigates the effects of cell context perturbations due to off-target regulation and resource competition. Our work thus lays the foundation for establishing tunable, precise, and robust control over cell behavior with synthetic signaling networks.

synthetic biology↗

bioRxiv2021

Species richness determines C. difficile invasion outcome in synthetic human gut communities

Understanding the principles of colonization resistance of the gut microbiome to the pathogen Clostridioides difficile will enable the design of next generation defined bacterial therapeutics. We investigate the ecological principles of community resistance to C. difficile invasion using a diverse synthetic human gut microbiome. Our results show that species richness is a key determinant of C. difficile growth across a wide range of ecological contexts. Using a dynamic computational model, we demonstrate that C. difficile receives the largest number and magnitude of incoming negative interactions. We identify molecular mechanisms of inhibition including acidification of the environment and competition over glucose. We demonstrate that C. difficiles close relative Clostridium hiranonis strongly inhibits C. difficile via a pH-independent mechanism. While increasing the initial density of C. difficile can increase its abundance in the assembled community, the community context determines the maximum achievable C. difficile abundance. Our work suggests that the C. difficile inhibitory potential of defined bacterial therapeutics can be optimized by designing communities that feature a combination of mechanisms including species richness, environment acidification, and resource competition.

systems biology↗

bioRxiv2021

Direct activation of endothelial cells by SARS-CoV-2 nucleocapsid protein is blocked by Simvastatin

Emerging evidence suggests that endothelial activation plays a central role in the pathogenesis of acute respiratory distress syndrome (ARDS) and multi-organ failure in patients with COVID-19. However, the molecular mechanisms underlying endothelial activation in COVID-19 patients remain unclear. In this study, the SARS-CoV-2 viral proteins that potently activate human endothelial cells were screened to elucidate the molecular mechanisms involved with endothelial activation. It was found that nucleocapsid protein (NP) of SARS-CoV-2 significantly activated human endothelial cells through TLR2/NF-{kappa}B and MAPK signaling pathways. Moreover, by screening a natural microbial compound library containing 154 natural compounds, simvastatin was identified as a potent inhibitor of NP-induced endothelial activation. Remarkablely, though the protein sequences of N proteins from coronaviruses are highly conserved, only NP from SARS-CoV-2 induced endothelial activation. The NPs from other coronaviruses such as SARS-CoV, MERS-CoV, HUB1-CoV and influenza virus H1N1 did not affect endothelial activation. These findings are well consistent with the results from clinical investigations showing broad endotheliitis and organ injury in severe COVID-19 patients. In conclusion, the study provides insights on SARS-CoV-2-induced vasculopathy and coagulopathy, and suggests that simvastatin, an FDA-approved lipid-lowering drug, may benefit to prevent the pathogenesis and improve the outcome of COVID-19 patients.

immunology↗