Biology subjects

Tu, C.

Publications and source records attributed to Tu, C..

15 recordsLinked to original sources

bioRxiv2024

Sequential emergence and contraction of epithelial subtypes in the prenatal human choroid plexus revealed by a stem cell model

Despite the major roles of choroid plexus epithelial cells (CPECs) in brain homeostasis and repair, their developmental lineage and diversity remain undefined. In simplified differentiations from human pluripotent stem cells, derived CPECs (dCPECs) displayed canonical properties and dynamic multiciliated phenotypes that interacted with A{beta} uptake. Single dCPEC transcriptomes over time correlated well with human organoid and fetal CPECs, while pseudotemporal and cell cycle analyses highlighted the direct CPEC origin from neuroepithelial cells. In addition, time series analyses defined metabolic (type 1) and ciliogenic dCPECs (type 2) at early timepoints, followed by type 1 diversification into anabolic-secretory (type 1a) and catabolic-absorptive subtypes (type 1b) as type 2 cells contracted. These temporal patterns were then confirmed in independent derivations and mapped to prenatal stages using human tissues. In addition to defining the prenatal lineage of human CPECs, these findings suggest new dynamic models of ChP support for the developing human brain.

neuroscience↗

bioRxiv2023

Detection and characterization of a novel bat filovirus (Dehong virus, DEHV) in fruit bats

Although bats are natural hosts of most filoviruses (FiVs), with the pathogenic ones frequently causing deadly haemorrhagic fevers in Africa, the viruses are difficult to trace. Recently, multiple divergent FiVs have been uncovered in China, raising concerns about their threat to public health. Here we report the detection of bat-borne FiVs at the interface of orchards between bats and humans, eventually resulting in the discovery of a novel FiV, Dehong virus (DEHV), from Rousettus leschenaultii (R. leschenaultii) bats. DEHV has the largest genome, and the phylogeny places it between the genera Dianlovirus and Marburgvirus, suggesting its classification as a prototype of a new genus within the family Filoviridae. Our study emphasizes the importance of further understanding the distribution and potential risk of FiVs in the region.

microbiology↗

bioRxiv2022

Respiratory mucosal vaccination of peptide-poloxamine-DNA nanoparticles provides complete protection against lethal SARS-CoV-2 challenge

The ongoing SARS-CoV-2 pandemic represents a brutal reminder of the continual threat of mucosal infectious diseases. Mucosal immunity may provide robust protection at the predominant sites of SARS-CoV-2 infection. However, it remains unclear whether respiratory mucosal administration of DNA vaccines could confer protective immune responses against SARS-CoV-2 challenge due to the insurmountable barriers posed by the airway. Here, we applied self-assembled peptide-poloxamine nanoparticles with mucus-penetrating properties for pulmonary inoculation of a COVID-19 DNA vaccine (pSpike/PP-sNp). Not only displays the pSpike/PP-sNp superior gene-transfection and favorable biocompatibility in the mouse airway, but pSpike/PP-sNp promotes a tripartite immunity consisting of systemic, cellular and mucosal immune responses that are characterized by mucosal IgA secretion, high levels of neutralizing antibodies, and resident memory phenotype T-cell responses in the lungs of mice. Most importantly, pSpike/PP-sNp completely eliminates SARS-CoV-2 infection in both upper and lower respiratory tracts and enables 100% survival rate of mice following lethal SARS-CoV-2 challenge. Our findings indicate PP-sNp might be a promising platform in mediating DNA vaccines to elicit all-around mucosal immunity against SARS-CoV-2.

immunology↗

bioRxiv2022

De-heterogeneity of the eukaryotic viral reference database (EVRD) improves the accuracy and efficiency of viromic analysis

Widespread in public databases, the notorious contamination in virus reference databases often leads to confusing even wrong conclusions in applications like viral disease diagnosis and viromic analysis, highlighting the need of a high-quality database. Here, we report the comprehensive scrutiny and the purification of the largest viral sequence collections of GenBank and UniProt by detection and characterization of heterogeneous sequences (HGSs). A total of 766 nucleotide- and 276 amino acid-HGSs were determined with length up to 6,605 bp, which were widely distributed in 39 families, with many involving highly public health-related viruses, such as hepatitis C virus, Crimea-Congo hemorrhagic fever virus and filovirus. Majority of these HGSs are sequences of a wide range of hosts including humans, with the rest resulting from vectors, misclassification and laboratory components. However, these HGSs cannot be simply considered as exotic contaminants, since part of which are resultants of natural occurrence or artificial engineering of the viruses. Nevertheless, they significantly disturb the genomic analysis, and hence were deleted from the database. A further augmentation was implemented with addition of the risk and vaccine sequences, which finally results in a high-quality eukaryotic virus reference database (EVRD). EVRD showed higher accuracy and less time-consuming without coverage compromise by reducing false positives than other integrated databases in viromic analysis. EVRD is freely accessible with favorable application in viral disease diagnosis, taxonomic clustering, viromic analysis and novel virus detection.

microbiology↗

bioRxiv2022

Proteomic network analysis of bronchoalveolar lavage fluid in ex-smokers to discover implicated protein targets and novel drug treatments for chronic obstructive pulmonary disease

RationaleBronchoalveolar lavage of the epithelial lining fluid can sample the profound changes in the airway lumen milieu prevalent in Chronic Obstructive Pulmonary Disease (COPD). Characterizing the proteins in bronchoalveolar lavage fluid in COPD with advanced proteomic methods will identify disease-related changes, provide insight into pathogenetic mechanisms and potential therapeutics that will aid in the discovery of more effective therapeutics for COPD. ObjectivesWe compared epithelial lining fluid proteome of ex-smokers with moderate COPD who are not in exacerbation status COPD, to non-smoking healthy control subjects using advanced proteomics methods and applied proteome-scale translational bioinformatics approaches to identify potential therapeutic protein targets and drugs that modulate these proteins towards the treatment of COPD. MethodsProteomic profiles of bronchalveolar lavage fluid were obtained from 1) never-smoker control subjects with normal lung function (n=10) or 2) individuals with stable moderate (GOLD stage 2, FEV1 50% - 80% predicted) COPD who were ex-smokers for at least one year (n=10). NIHs Database for Annotation, Visualization and Integrated Discovery (DAVID) and Ingenuitys Ingenuity Pathway Analysis (IPA) were the two bioinformatics tools employed for network analysis on the differentially expressed proteins to identify potential crucial hub proteins. The drug-proteome interaction signature comparison and ranking approach implemented in the Computational Analysis of Novel Drug Opportunities (CANDO) platform for multiscale therapeutic discovery was utilized to identify potential repurposable drugs for the treatment of COPD based on the BALF proteome. Subsequently, a literature-based knowledge graph was utilized to rank combinations of drugs that would most likely ameloriate inflammatory processes by inhibition or activation of their functions. ResultsProteomic network analysis demonstrated that 233 of the >1800 proteins identified in the BALF were differentially expressed in COPD versus control, including proteins associated with inflammation, structural elements, and energy metabolism. Functional annotation of the differentially expressed proteins by their implicated biological processes, cellular localization, and transcription factor interactions was accomplished via DAVID. Canonical pathways containing the differential expressed proteins were detailed via the Ingenuity Pathway Analysis application. Topological network analysis demonstrated that four proteins act as central node proteins in the inflammatory pathways in COPD. The CANDO multiscale drug discovery platform was used to analyze the behavioral similarity between the interaction signatures of all FDA-approved drugs and the identified BALF proteins. The drugs with the signatures most similar interaction signatures to approved COPD drugs were extracted with the CANDO platform. The analysis revealed 189 drugs that putatively target the proteins implicated in COPD. The putative COPD drugs that were identified using CANDO were subsequently analyzed using a knowledge based technique to identify an optimal two drug combination that had the most appropriate effect on the central node proteins. ConclusionAnalysis of the BALF proteome revealed novel differentially expressed proteins in the epithelial lining fluid that elucidate COPD pathogenesis. Network analyses identified critical targets that have critical roles in modulating COPD pathogenesis, for which we identified several drugs that could be repurposed to treat COPD using a multiscale shotgun drug discovery approach.

bioinformatics↗

bioRxiv2021

Broad neutralization of SARS-CoV-2 variants by an inhalable bispecific single-domain antibody

The effectiveness of SARS-CoV-2 vaccines and therapeutic antibodies has been limited by the continuous emergence of viral variants, and by the restricted diffusion of antibodies from circulation into the sites of respiratory virus infection. Here, we report the identification of two highly conserved regions on Omicron variant RBD recognized by broadly neutralizing antibodies. Based on this finding, we generated a bispecific single-domain antibody that was able to simultaneously and synergistically bind these two regions on a single Omicron variant RBD as revealed by Cryo-EM structures. This inhalable antibody exhibited exquisite neutralization breadth and therapeutic efficacy in mouse models of SARS-CoV-2 infections. The structures also deciphered an uncommon cryptic epitope within the spike trimeric interface that may have implications for the design of broadly protective SARS-CoV-2 vaccines and therapeutics.

immunology↗

bioRxiv2021

Total virome characterizations of game animals in China reveals a spectrum of emerging viral pathogens

Game animals are wildlife species often traded and consumed as exotic food, and are potential reservoirs for SARS-CoV and SARS-CoV-2. We performed a meta-transcriptomic analysis of 1725 game animals, representing 16 species and five mammalian orders, sampled across China. From this we identified 71 mammalian viruses, with 45 described for the first time. Eighteen viruses were considered as potentially high risk to humans and domestic animals. Civets (Paguma larvata) carried the highest number of potentially high risk viruses. We identified the transmission of Bat coronavirus HKU8 from a bat to a civet, as well as cross-species jumps of coronaviruses from bats to hedgehogs and from birds to porcupines. We similarly identified avian Influenza A virus H9N2 in civets and Asian badgers, with the latter displaying respiratory symptoms, as well as cases of likely human-to-wildlife virus transmission. These data highlight the importance of game animals as potential drivers of disease emergence. HighlightsO_LI1725 game animals from five mammalian orders were surveyed for viruses C_LIO_LI71 mammalian viruses were discovered, 18 with a potential risk to humans C_LIO_LICivets harbored the highest number of potential high risk viruses C_LIO_LIA species jump of an alphacoronavirus from bats to a civet was identified C_LIO_LIH9N2 influenza virus was detected in a civet and an Asian badger C_LIO_LIHumans viruses were also identified in game animals C_LI

zoology↗

bioRxiv2021

Classical swine fever virus NS5A inhibits NF-κB signaling by targeting NEMO

The NS5A non-structural protein of classical swine fever virus (CSFV) is a multifunctional protein involved in viral genomic replication, protein translation and regulation of cellular signaling pathways, and assembly of infectious virus particles. Previous report showed that NS5A inhibited nuclear factor kappa B (NF-{kappa}B) signaling induced by poly(I:C); however, the mechanism was not elucidated. Here, we report that NS5A interacts with NF-{kappa}B essential modulator (NEMO),a regulatory subunit of the I{kappa}B kinase (IKK) complex, and that the zinc finger domain of NEMO essential for NEMO ubiquitination and IKK activation is required for the interaction of NEMO with NS5A. Viral infection or NS5A expression by itself reduced the protein level of NEMO. Mechanistic analysis revealed that NS5A mediated proteasomal degradation of NEMO. Ubiquitination assay showed that NS5A induced K27-but not K48-linked polyubiquitination of NEMO. In addition, NS5A blocked k63-linked polyubiquitination of NEMO, thereby inhibiting activation of IKK and NF-{kappa}B. These findings indicate that NS5A inhibits NF-{kappa}B signaling by mediating proteasomal degradation of NEMO and blocking k63-linked polyubiquitination of NEMO, thereby revealing a novel mechanism by which CSFV inhibits host innate immunity. ImportanceClassical swine fever (CSF) is a economically important swine viral disease leading to hemorrhagic fever and immuno-suppression. In order to successfully infect and replicate in a host cell, viruses have evolved various strategies to antagonize host innate immunity. It is known that CSFV non-structural protein Npro interacts with interferon regulatory factor 3 (IRF3) and mediates its proteasomal degradation, thereby inhibiting the production of type I interferon. However, no other mechanism by which CSFV antagonizes host innate immunity has so far been reported. Here, we show that NS5A inhibits NF-{kappa}B signaling by mediating proteasomal degradation of NEMO and by blocking k63-linked polyubiquitination of NEMO, thereby revealing a novel mechanism by which CSFV antagonizes host innate immunity.

microbiology↗

bioRxiv2020

Life histories decide reserve benefits in transient yields and bycatch persistence

Recent research indicates that marine reserves can both improve fisheries yields of target species and maintain the persistence of bycatch species. However, the prevalent equilibrium analyses prevent our understandings in transient behavior at short-time scales. Here, we develop high dimensional theoretical frameworks by considering age structure to assess the relative advantages between reserve-only and no-reserve fisheries management strategies. Our results show that whether strategies with only reserves can achieve higher fisheries yields (measured by both weight and number) and maintain bycatch persistence depends on the life histories of both target and bycatch species through perspectives of transient oscillations. Our research has important practical applications especially for the West Coast groundfish fishery in the USA, as it suggests that reserves can perform benefits in both fisheries and conservation goals for target species with older ages at maturity and lower adult survivorship.

ecology↗

bioRxiv2020

Fully human single-domain antibodies against SARS-CoV-2

The COVID-19 pandemic is spreading rapidly, highlighting the urgent need for an efficient approach to rapidly develop therapeutics and prophylactics against SARS-CoV-2. We describe here the development of a phage-displayed single-domain antibody library by grafting naive CDRs into framework regions of an identified human germline IGHV allele. This enabled the isolation of high-affinity single-domain antibodies of fully human origin. The panning using SARS-CoV-2 RBD and S1 as antigens resulted in the identification of antibodies targeting five types of neutralizing or non-neutralizing epitopes on SARS-CoV-2 RBD. These fully human single-domain antibodies bound specifically to SARS-CoV-2 RBD with subnanomolar to low nanomolar affinities. Some of them were found to potently neutralize pseudotyped and live virus, and therefore may represent promising candidates for prophylaxis and therapy of COVID-19. This study also reports unique immunogenic profile of SARS-CoV-2 RBD compared to that of SARS-CoV and MERS-CoV, which may have important implications for the development of effective vaccines against SARS-CoV-2.

microbiology↗

bioRxiv2019

Contrast-Enhanced, Molecular Imaging of Vascular Inflammation in the Mouse Model by Simultaneous PET/MRI

Despite advances in diagnosis and management, cardiovascular diseases (CVDs) remain the leading cause of death in the US. Atherosclerosis is the most common form of CVD and the vulnerability of atherosclerotic plaques to rupture is a primary determinant for risk of catastrophic ischemic events. Current imaging of atherosclerotic disease focuses on assessing plaque size and the degree of luminal stenosis, which are not good predictors of plaque stability. Functional methods to identify biomarkers of inflammation in plaques could facilitate assessment of plaque instability to allow early intervention. In this study, we validate the use of a purpose-built, magnetic resonance imaging (MRI)-compatible positron emission tomography (PET) insert for multimodal, molecular imaging of vulnerable plaques in mice. We illustrate the application of PET to screen for inflamed regions to guide the application of MRI. Molecular MRI visualizes regions of vascular inflammation and is coupled with anatomical MRI to generate detailed maps of the inflammatory marker within the context of an individual vessel. As a testbed for this imaging methodology, we developed a multimodal, iron oxide nanoparticle (NP) targeting vascular cell adhesion molecule-1 (VCAM-1) for simultaneous PET/MRI of vascular inflammation performed on a mouse carotid ligation model. In vitro cell studies confirmed that the NPs are not cytotoxic to liver cells. In vivo simultaneous PET/MRI imaging identified regions of inflammation. Three-dimensional rendering of the MRI data facilitated high-resolution visualization of patterns of inflammation along the injured vessel. Histology validated the co-localization of the NPs with VCAM-1 expression at sites of induced inflammation. The results of this work validate the utility of the simultaneous PET/MR insert as a research tool for small animals and lays groundwork to further advance the potential clinical utility of integrated imaging systems.

bioengineering↗

bioRxiv2019

Extensive genetic diversity of bat-borne polyomaviruses reveals inter-family host-switching events

Polyomaviruses (PyVs) are small, double-stranded DNA tumor viruses carried by diverse vertebrates. PyVs have previously been considered highly host restricted in mammalian hosts, with host-switching events thought rare or nonexistent. Prior investigations have revealed short-range host-switching events of PyVs in two different African bat species within the horseshoe bat genus Rhinolophus. Herein, we have conducted a systematic investigation of PyVs in 1,083 archived bat samples collected from five provinces across China, and identified 192 PyVs from 186 bats from 15 host species within 6 families (Rhinolophidae, Vespertilionidae, Hipposideridae, Emballonuridae, Miniopteridae and Pteropodidae) representing 28 newly-described PyVs, indicative of extensive genetic diversity of bat PyVs. Surprisingly, two PyVs were identified in multiple bat species from different families, and another PyV clustered phylogenetically with PyVs carried by bats from a different host family, indicative of three inter-family PyV host-switching events. The time to most recent common ancestor (tMRCA) of the three events was estimated at 0.02-11.6 million years ago (MYA), which is inconsistent with the estimated tMRCA of their respective bat hosts (36.3-66.7 MYA), and is most parsimoniously explained by host-switching events. PyVs identified from geographically separated Chinese horseshoe bat species in the present study showed close genetic identities, and clustered with each other and with PyVs from African horseshoe bats, allowing assessment of the effects of positive selection in VP1 within the horseshoe bat family Rhinolophidae. Correlation analysis indicated that co-evolution with their hosts contributed much more to evolutionary divergence of PyV than geographic distance. In conclusion, our findings provide the first evidence of inter-family host-switching events of PyV in mammals and challenge the prevailing evolutionary paradigm for strict host restriction of mammalian PyVs.\n\nAuthor summarySince the discovery of murine polyomavirus in the 1950s, polyomaviruses (PyVs) have been considered both genetically stable and highly host-restricted in their mammalian hosts. In this study, we have identified multiple cases of host-switching events of PyVs by large scale surveillance in diverse bat species collected in China. These host-switching events occurred between bat families living in the same colony, indicating that a large population with frequent contacts between different bat species may represent an ecological niche facilitating PyV host-switching. The cases studied involved members of bats from several families, including horseshoe bats, which were previously found to harbor a number of highly virulent viruses to both humans and domestic animals. Our findings have provided evidence that even highly host-specific DNA viruses can transmit between bats of different species and indicate an increased propensity for spillover events involving horseshoe bats. We propose an evolutionary scheme for bat-borne PyVs in which intra-host divergence and host-switching has generated the diverse PyVs in present day bats. This scheme provides a useful model to study the evolution of PyVs in other hosts and, potentially, the modeling of bat zoonoses and the transmission of other DNA viruses in other mammals, including humans.

microbiology↗

bioRxiv2018

Rgs12 enhances osteoclastogenesis by suppressing Nrf2 activity and promoting the formation of reactive oxygen species

The Regulator of G-protein Signaling 12 (Rgs12) is important for osteoclast (OC) differentiation, and its deletion in vivo protected mice against pathological bone loss. To characterize its mechanism in osteoclastogenesis, we selectively deleted Rgs12 in OC precursors using the LysM-Cre transgenic line or overexpressed the gene in RAW264.7 cells. Rgs12 deletion led to increased bone mass with decreased OC numbers, whereas its overexpression increased OC number and size. Proteomics analysis of Rgs12-deficient OCs identified an upregulation of antioxidant enzymes under the transcriptional regulation of Nrf2, the master regulator of oxidative stress. We confirmed an increase of Nrf2 activity and impaired production in Rgs12-deficient cells. Conversely, Rgs12 overexpression suppressed Nrf2 through a mechanism dependent on the 26S proteasome, and promoted RANKL-induced phosphorylation of ERK1/2 and NF{kappa}B, which was abrogated by antioxidant treatment. We therefore identified a novel role of Rgs12 in regulating Nrf2, thereby controlling cellular redox state and OC differentiation.

cell biology↗

bioRxiv2018

Genetically modified pigs are protected from classical swine fever virus

Classical swine fever (CSF) caused by classical swine fever virus (CSFV) is among the most detrimental diseases, and leads to significant economic losses in the swine industry. Despite efforts by many government authorities try to stamp out the disease from national pig populations, the disease remains widespread. Here, antiviral small hairpin RNAs (shRNAs) were selected and then inserted at the porcine ROSA26 (pROSA26) locus via a CRISPR/Cas9-mediated knock-in strategy. Finally, anti-CSFV transgenic (TG) pigs were produced by somatic nuclear transfer (SCNT). Importantly, in vitro and in vivo viral challenge assays demonstrated that these TG pigs could effectively limit the growth of CSFV and reduced CSFV-associated clinical signs and mortality, and the disease resistance was stably transmitted to F1-generation. The use of these TG pigs can improve the well-being of livestock and substantially reduce virus-related economic losses. Additionally, this antiviral approach may provide a reference for future antiviral research.\n\nAuthor summaryClassical swine fever (CSF), caused by classical swine fever virus (CSFV), and is a highly contagious, often fatal porcine disease with significant economic losses. Due to its economic importance to the pig industry, the biology and pathogenesis of CSFV have been investigated extensively. Despite efforts by many government authorities to stamp out the disease from national pig populations, the disease remains widespread in some regions and seems to be waiting for the reintroduction and the next round of disease outbreaks. These highlight the necessity and urgency of developing more effective approaches to eradicate the challenging CSFV. In this study, we successfully produced anti-CSFV transgenic pigs and confirmed that these transgenic pigs could effectively limit the growth of CSFV in vivo and in vitro and that the disease resistance traits in the TG founders can be stably transmitted to their F1-generation offspring. This study suggests that these TG pigs can improve the well-being of livestock and contribute to offer potential benefits over commercial vaccination. The use of these TG pigs can improve the well-being of livestock and substantially reduce CSFV-related economic losses.

genomics↗

bioRxiv2018

Selective inhibition of CA IX over CA XII using benzene sulfonamides: Disconnect between CA activity and growth inhibition in breast cancer cells

Carbonic anhydrases (CAs) have been linked to tumor progression, particularly membrane-bound CA isoform IX (CA IX). The role of CA IX in the context of breast cancer is to regulate the pH of the tumor microenvironment. In contrast to CA IX, expression of CA XII, specifically in breast cancer, is associated with better outcome despite performing the same catalytic function. In this study, we have structurally modeled the orientation of bound ureido-substituted benzene sulfonamides (USBs) within the active site of CA XII, in comparison to CA IX and cytosolic off-target CA II, to understand isoform specific inhibition. This has identified specific residues within the CA active site, which differ between isoforms that are important for inhibitor binding and isoform specificity. The ability of these sulfonamides to block CA IX activity in breast cancer cells is less effective than their ability to block activity of the recombinant protein (by one to two orders of magnitude depending on the inhibitor). The same is true for CA XII activity but now they are two to three orders of magnitude less effective. Thus, there is significantly greater specificity for CA IX activity over CA XII. While the inhibitors block cell growth, without inducing cell death, this again occurs at two orders of magnitude above the Ki values for inhibition of CA IX and CA XII activity in their respective cell types. Surprisingly, the USBs inhibited cell growth even in cells where CA IX and CA XII expression was ablated. Despite the potential for these sulfonamides as chemotherapeutic agents, these data suggest that we reconsider the role of CA activity on growth potentiation.

cancer biology↗