bioRxiv Science⌕ Search

Biology subjects

Liang, Y.

Publications and source records attributed to Liang, Y..

At least 289 records · Page 16Linked to original sources

ERK1/2 is an ancestral organising signal in spiral cleavage

Animal development is classified as conditional or autonomous based on whether cell fates are specified through inductive signals or maternal determinants, respectively. Yet how these two major developmental modes evolved remains unclear. During spiral cleavage--a stereotypic embryogenesis ancestral to 15 invertebrate groups, including molluscs and annelids--most lineages specify cell fates conditionally, while some define the primary axial fates autonomously. To identify the mechanisms driving this change, we studied Owenia fusiformis, an early-branching, conditional annelid. In Owenia, ERK1/2-mediated FGF receptor signalling specifies the endomesodermal progenitor. This cell likely acts as an organiser, inducing mesodermal and posterodorsal fates in neighbouring cells and repressing anteriorising signals. The organising role of ERK1/2 in Owenia is shared with molluscs, but not with autonomous annelids. Together, these findings suggest that conditional specification of an ERK1/2+ embryonic organiser is ancestral in spiral cleavage and was repeatedly lost in annelid lineages with autonomous development.

developmental biology↗

Broad neutralization against SARS-CoV-2 variants induced by a modified B.1.351 protein-based COVID-19 vaccine candidate

Beginning in late 2020, the emergence and spread of multiple variant SARS-CoV-2 strains harboring mutations which may enable immune escape necessitates the rapid evaluation of second generation COVID-19 vaccines, with the goal of inducing optimized immune responses that are broadly protective. Here we demonstrate in a mouse immunogenicity study that two doses of a modified B.1.351 spike (S)-Trimer vaccine (B.1.351 S-Trimer) candidate can induce strong humoral immune responses that can broadly neutralize both the original SARS-CoV-2 strain (Wuhan-Hu-1) and Variants of Concern (VOCs), including the UK variant (B.1.1.7), South African variant (B.1.351) and Brazil variant (P.1). Furthermore, while immunization with two doses (prime-boost) of Prototype S-Trimer vaccine (based on the original SARS-CoV-2 strain) induced lower levels of cross-reactive neutralization against the B.1.351 variant, a third dose (booster) administered with either Prototype S-Trimer or B.1.351 S-Trimer was able to increase neutralizing antibody titers against B.1.351 to levels comparable to neutralizing antibody titers against the original strain elicited by two doses of Prototype S-Trimer.

immunology↗

Pigment pattern morphospace of Danio fishes: evolutionary diversification and mutational effects

Molecular and cellular mechanisms underlying differences in adult form remain largely unknown. Adult pigment patterns of fishes in the genus Danio, which includes zebrafish, D. rerio, include horizontal stripes, vertical bars, spots and uniform patterns, and provide an outstanding opportunity to identify causes of species level variation in a neural crest derived trait. Yet understanding such variation requires quantitative approaches to assess phenotypes, and such methods have been mostly lacking for pigment patterns. We introduce metrics derived from information theory that describe patterns and pattern variation in Danio fishes. We find that such metrics used singly and in multivariate combinations are suitable for distinguishing general pattern types, and can reveal even subtle phenotypic differences attributable to mutations. Our study provides new tools for analyzing pigment pattern in Danio and potentially other groups, and sets the stage for future analyses of pattern morphospace and its mechanistic underpinnings. Summary statementWe provide quantitative metrics for studying pigment patterns of zebrafish and other species. These metrics are applicable to changes between species as well as impacts of laboratory induced mutations

developmental biology↗

A meta-analysis of Microarray Data is Effective for Identifying Gravity-Sensitive Genes

Gravity affects the function and maintenance of organs, such as bones, muscles, and the heart. Several studies have used DNA microarrays to identify genes with altered expressions in response to gravity. However, it is technically challenging to combine the results from various microarray datasets because of their different data structures. We hypothesized it is possible to identify common changes in gene expression from the DNA microarray datasets obtained under various conditions and methods. In this study, we grouped homologous genes to perform a meta-analysis of multiple vascular endothelial cell and skeletal muscle datasets. According to the t-distributed stochastic neighbor embedding (t-SNE) analysis, the changes in the gene expression pattern in vascular endothelial cells formed specific clusters. We also identified candidate genes in endothelial cells that responded to gravity. Further, we exposed human umbilical vein endothelial cells to simulated microgravity using a clinostat and measured the expression levels of the candidate genes. Gene expression analysis using qRT-PCR revealed that the expression level of the prostaglandin transporter gene SLCO2A1 decreased in response to microgravity, consistent with the meta-analysis of microarray datasets. Furthermore, the direction of gravity affected the expression level of SLCO2A1, buttressing the finding that its expression was affected by gravity. These results suggest that a meta-analysis of DNA microarray datasets may help identify new target genes previously overlooked in individual microarray analyses.

cell biology↗

A cell-ECM mechanism for connecting the ipsilateral eye to the brain

Information about features in the visual world are parsed by circuits in the retina and are then transmitted to the brain by distinct subtypes of retinal ganglion cells (RGCs). Axons from RGC subtypes are stratified in retinorecipient brain nuclei, such as the superior colliculus (SC), to provide a segregated relay of parallel and feature-specific visual streams. Here, we sought to identify the molecular mechanisms that direct the stereotyped laminar targeting of these axons. We focused on ipsilateral-projecting subtypes of RGCs (ipsiRGCs) whose axons target a deep SC sublamina. We identified an extracellular glycoprotein, Nephronectin (NPNT), whose expression is restricted to this ipsiRGC-targeted sublamina. SC-derived NPNT and integrin receptors generated by ipsiRGCs are both required for the targeting of ipsiRGC axons to the deep sublamina of SC. Thus, a cell-extracellular matrix (ECM) recognition mechanism specifies precise laminar targeting of ipsiRGC axons and the assembly of eye-specific parallel visual pathways. Significance StatementDistinct features of the visual world are transmitted from the retina to the brain through anatomically segregated circuits. Despite this being an organizing principle of visual pathways in mammals, we lack an understanding of the signaling mechanisms guiding axons of different types of retinal neurons into segregated layers of brain regions. We explore this question by identifying how axons from the ipsilateral retina innervate a specific lamina of the superior colliculus. Our studies reveal a unique cell-extracellular matrix (ECM) recognition mechanism that specifies precise targeting of these axons to the superior colliculus. Loss of this mechanism not only resulted in the absence of this eye-specific visual circuit, but it led to an impairment of innate predatory visual behavior as well.

neuroscience↗

Role of BRCA2 DNA-binding and C-terminal domain on its mobility and conformation in DNA repair

BRCA2 is an essential protein in genome maintenance, homologous recombination and replication fork protection. Its function includes multiple interaction partners and requires timely localization to relevant sites in the nucleus. We investigated the importance of the highly conserved DNA binding domain (DBD) and C-terminal domain (CTD) of BRCA2. We generated BRCA2 variants missing one or both domains in mouse ES cells and defined their contribution in HR function and dynamic localization in the nucleus, by single particle tracking of BRCA2 mobility. Changes in molecular architecture of BRCA2 induced by binding partners of purified BRCA2 was determined by scanning force microscopy. BRCA2 mobility and DNA damage-induced increase in the immobile fraction was largely unaffected by C- terminal deletions. The purified proteins missing CTD and/or DBD were defective in architectural changes correlating with reduced homologous recombination function in cells. These results emphasize BRCA2 activity at sites of damage beyond promoting RAD51 delivery.

molecular biology↗

Cinnamoyl-CoA Reductase 1 (CCR1) and CCR2 Function Divergently in Tissue Lignification, Flux Control and Cross-talk with Glucosinolate Pathway in Brassica napus

Cinnamoyl-CoA reductase (CCR) is the entry point of lignin pathway and a crucial locus in dissection and manipulation of associated traits, but its functional dissection in Brassicaceae plants is largely lagged behind though Arabidopsis thaliana CCR1 has been characterized to certain extent. Here, 16 CCR genes are identified from Brassica napus and its parental species B. rapa and B. oleracea. Brassicaceae CCR genes are divided into CCR1 subfamily and CCR2 subfamily with divergent organ-specificity, yellow-seed trait participation and stresses responsiveness. CCR1 is preferential in G- and H-lignins biosynthesis and vascular development, while CCR2 has a deviation to S-lignin biosynthesis and interfascicular fiber development. CCR1 has stronger effects on lignification-related development, lodging resistance, phenylpropanoid flux control and seed coat pigmentation, whereas CCR2 controls sinapates levels. CCR1 upregulation could delay bolting and flowering time, while CCR2 upregulation weakens vascular system in leaf due to suppressed G lignin accumulation. Besides, CCR1 and CCR2 are deeply but almost oppositely linked with glucosinolates metabolism through inter-pathway crosstalk. Strangely, upregulation of both CCR1 and CCR2 could not enhance resistance to UV-B and S. sclerotiorum though CCR2 is sharply induced by them. These results provide systemic dissection on Brassica CCRs and CCR1-CCR2 divergence in Brassicaceae. HighlightBrassicaceae contains two types of Cinnamoyl-CoA reductase. As revealed in Brassica napus, they are divergently involved in lignin monomer biosynthesis, tissue lignification, phenylpropanoid flux control, and inter-pathway crosstalk with glucosinolates.

plant biology↗

REVA as a Well-curated Database for Human Expression-modulating Variants

More than 80% of disease- and trait-associated human variants are noncoding. By systematically screening multiple large-scale studies, we compiled REVA, a manually curated database for over 11.8 million experimentally tested noncoding variants with expression-modulating potentials. We provided 2424 functional annotations that could be used to pinpoint plausible regulatory mechanism of these variants. We further benchmarked multiple state-of-the-art computational tools and found their limited sensitivity remains a serious challenge for effective large-scale analysis. REVA provides high-qualify experimentally tested expression-modulating variants with extensive functional annotations, which will be useful for users in the noncoding variants community. REVA is available at http://reva.gao-lab.org.

bioinformatics↗

Familial prion disease-related mutation E196K displays a novel amyloid fibril structure revealed by cryo-EM

Prion diseases are caused by the conformational conversion of prion protein (PrP) from its cellular form (PrPC) into a protease-resistant, aggregated form (PrPSc). 42 different familial mutations were identified in human PrP, which lead to genetic prion diseases with distinct clinical syndromes. Here we report cryo-EM structure of an amyloid fibril formed by full-length human PrP with E196K mutation, a familial Creutzfeldt-Jakob disease-related mutation. This mutation disrupts key interactions in wild-type PrP fibril and results in a rearrangement of the overall structure, forming an amyloid fibril with a conformation distinct from wild-type PrP fibril. The E196K fibril consists of two protofibrils intertwined into a left-handed helix. Each subunit forms five {beta}-strands stabilized by a disulfide bond and an unusual hydrophilic cavity. Two pairs of amino acids (Lys194 and Glu207; Lys196 and Glu200) from opposing subunits form four salt bridges to stabilize the zigzag interface of the two protofibrils. Furthermore, the E196K fibril exhibits a significantly lower conformational stability and protease resistance activity than the wild-type fibril. Our results provide direct structural evidences of the diverse mammalian prion strains and fibril polymorphism of PrP, and highlight the importance of familial mutations in determining the different prion strains.

biochemistry↗

E484K mutation in SARS-CoV-2 RBD enhances binding affinity with hACE2 but reduces interactions with neutralizing antibodies and nanobodies: Binding free energy calculation studies

The pandemic of the COVID-19 disease caused by SARS-CoV-2 has led to more than 100 million infections and over 2 million deaths worldwide. The progress in the developments of effective vaccines and neutralizing antibody therapeutics brings hopes to eliminate the threat of COVID-19. However, SARS-CoV-2 continues to mutate, and several new variants have been emerged. Among the various naturally-occurring mutations, the E484K mutation shared by both the 501Y.V2 and 501Y.V3 variants attracted serious concerns, which may potentially enhance the receptor binding affinity and reduce the immune response. In the present study, the molecular mechanism behind the impacts of E484K mutation on the binding affinity of the receptor-binding domain (RBD) with the receptor human angiotensin-converting enzyme 2 (hACE2) was investigated by using the molecular dynamics (MD) simulations combined with the molecular mechanics-generalized Born surface area (MMGBSA) method. Our results indicate that the E484K mutation results in more favorable electrostatic interactions compensating the burial of the charged and polar groups upon the binding of RBD with hACE2, which significantly improves the RBD-hACE2 binding affinity. Besides that, the E484K mutation also causes the conformational rearrangements of the loop region containing the mutant residue, which leads to more tight binding interface of RBD with hACE2 and formation of some new hydrogen bonds. The more tight binding interface and the new hydrogen bonds formation also contribute to the improved binding affinity of RBD to the receptor hACE2. In addition, six neutralizing antibodies and nanobodies complexed with RBD were selected to explore the effects of E484K mutation on the recognition of these antibodies to RBD. The simulation results show that the E484K mutation significantly reduces the binding affinities to RBD for most of the studied neutralizing antibodies, and the decrease in the binding affinities is mainly owing to the unfavorable electrostatic interactions caused by the mutation. Our studies revealed that the E484K mutation may improve the binding affinity between RBD and the receptor hACE2, implying more transmissibility of the E484K-containing variants, and weaken the binding affinities between RBD and the studied neutralizing antibodies, indicating reduced effectiveness of these antibodies. Our results provide valuable information for the effective vaccine development and antibody drugs design.

bioinformatics↗

An adaptive optics module for deep tissue multiphoton imaging in vivo

Understanding complex biological systems requires visualizing structures and processes deep within living organisms. We developed a compact adaptive optics module and incorporated it into two- and three-photon fluorescence microscopes, to measure and correct tissue-induced aberrations. We resolved synaptic structures in deep cortical and subcortical areas of the mouse brain, and demonstrated high-resolution imaging of neuronal structures and somatosensory-evoked calcium responses in the mouse spinal cord at unprecedented depths in vivo.

bioengineering↗

Human hepatocyte PNPLA3 148M exacerbates rapid non-alcoholic steatohepatitis development in chimeric mice

Advanced non-alcoholic fatty liver disease (NAFLD) is a rapidly emerging global health problem associated with pre-disposing genetic polymorphisms, most strikingly an isoleucine to methionine substitution in patatin-like phospholipase domain-containing protein 3 (PNPLA3-I148M). Here, we study how human hepatocytes with PNPLA3 148I and 148M variants engrafted in the livers of chimeric mice respond to a hypercaloric Western-style diet. As early as 4 weeks, mice developed dyslipidemia, impaired glucose tolerance, and steatohepatitis selectively in the human graft, followed by pericellular fibrosis after 8 weeks of hypercaloric feeding. The PNPLA3 148M variant, either from a homozygous 148M human donor or overexpressed in a homozygous 148I donor background, caused widespread microvesicular steatosis and even more severe steatohepatitis. We conclude that PNPLA3 148M in human hepatocytes exacerbates NAFLD. These models will facilitate mechanistic studies into human genetic variants associated with advanced fatty liver diseases.

pathology↗

Polygenic transcriptome risk scores improve portability of polygenic risk scores across ancestries

Polygenic risk scores (PRS) are on course to translate the results of genome-wide association studies (GWAS) into clinical practice. To date, most GWAS have been based on individuals of European-ancestry, meaning that the utility of PRS for non-European populations is limited because SNP effects and LD patterns may not be conserved across populations. We hypothesized that cross population prediction at the level of genes rather than SNPs would be more effective, since the effect of genes on traits is likely to be more highly conserved. Therefore, we developed a framework to convert effect sizes at SNPs into effect sizes for genetically predicted transcript abundance, which we used for prediction in non-European populations. We compared this approach, which we call polygenic transcriptome risk scores (PTRS), to PRS, using data from 17 quantitative traits that were measured in multiple ancestries (European, African, East Asian, and South Asian) by UK Biobank. On average, PTRS using whole blood predicted transcriptome had lower absolute prediction accuracy than PRS, as we expected since not all regulatory processes were captured by a single tissue. However, as hypothesized, we found that in the African target set, the portability (prediction accuracy relative to the European reference set) was significantly higher for PTRS than PRS (p=0.03) with additional gain when transcriptomic prediction models ancestry matched the target population (p=0.021). Taken together, our results suggest that using PTRS can improve prediction in underrepresented populations and that increasing the diversity of transcriptomic data may be an effective way to improve portability of GWAS results between populations and help reduce health disparities.

genetics↗

Human Identical Sequences of SARS-CoV-2 Promote Clinical Progression of COVID-19 by Upregulating Hyaluronan via NamiRNA-Enhancer Network

The COVID-19 pandemic is a widespread and deadly public health crisis. The pathogen SARS-CoV-2 replicates in the lower respiratory tract and causes fatal pneumonia. Although tremendous efforts have been put into investigating the pathogeny of SARS-CoV-2, the underlying mechanism of how SARS-CoV-2 interacts with its host is largely unexplored. Here, by comparing the genomic sequences of SARS-CoV-2 and human, we identified five fully conserved elements in SARS-CoV-2 genome, which were termed as "human identical sequences (HIS)". HIS are also recognized in both SARS-CoV and MERS-CoV genome. Meanwhile, HIS-SARS-CoV-2 are highly conserved in the primate. Mechanically, HIS-SARS-CoV-2, behaving as virus-derived miRNAs, directly target to the human genomic loci and further interact with host enhancers to activate the expression of adjacent and distant genes, including cytokines gene and angiotensin converting enzyme II (ACE2), a well-known cell entry receptor of SARS-CoV-2, and hyaluronan synthase 2 (HAS2), which further increases hyaluronan formation. Noteworthily, hyaluronan level in plasma of COVID-19 patients is tightly correlated with severity and high risk for acute respiratory distress syndrome (ARDS) and may act as a predictor for the progression of COVID-19. HIS antagomirs, which downregulate hyaluronan level effectively, and 4-Methylumbelliferone (MU), an inhibitor of hyaluronan synthesis, are potential drugs to relieve the ARDS related ground-glass pattern in lung for COVID-19 treatment. Our results revealed that unprecedented HIS elements of SARS-CoV-2 contribute to the cytokine storm and ARDS in COVID-19 patients. Thus, blocking HIS-involved activating processes or hyaluronan synthesis directly by 4-MU may be effective strategies to alleviate COVID-19 progression.

molecular biology↗

All-trans Retinoic Acid Regulates miR-106a-5p Inhibition of Autophagic in Developing Cleft Palates

BackgroundAll-trans retinoic acid (atRA) results in cleft palate, but the cellular and molecular mechanisms underlying the teratogenic effects on palatal development have not been fully elucidated. Autophagy interruption has been reported to seriously affect embryonic-cell differentiation and development. This study aimed to verify whether atRA-induced cleft palate occurs because atRA blocks autophagy and stemness of embryonic palatal mesenchyme (MEPM) cells, which are maintained via the phosphatase and tensin homolog (PTEN)/protein kinase B (Akt)/mammalian target of rapamycin (mTOR) autophagic signaling pathway, and inhibits osteogenic-differentiation potential of MEPM cells, which could lead to the development of cleft palate. MethodsTo assess the stemness and pluripotency of MEPM cells, we analyzed their surfacemarkers using immunofluorescence (IF) and flow cytometry (FCM). Differentiation potentials, such as osteogenic, adipogenic, and chondrogenic differentiation, were induced. We also investigated the role of the PTEN/Akt/mTOR autophagic signaling pathway, which maintains the stemness and pluripotency of MEPM cells. Using transmission electron microscopy (TEM), Western blot analysis, quantitative reverse transcriptase polymerase chain reaction (RT-qPCR), messenger ribonucleic acid (mRNA) microarray, dual-luciferase reporter system, and exosomes, we found that atRA blocks autophagy and osteogenic differentiation of MEPM cells through micro-ribonucleic acid (miR)-106a-5p by targeting the PTEN/Akt/mTOR autophagic pathway. ResultsIn vitro purified MEPM cells expressed cell surface markers similar to those of mouse bone marrow stem cells. Additionally, in vitro MEPM cells were ectomesenchymal and expressed the neural-crest marker human natural killer-1 (HNK-1), the mesodermal marker vimentin, and the ectodermal marker nestin. They were also positive for in vitro MEPM markers, including platelet-derived growth factor alpha (PDGFR), ephrin B1 (Efnb1), odd-skipped related 2 (Osr2), and Meox2, as well as for stemness markers including POU class 5 homeobox 4 (Oct4), Nanog, and sex-determining region Y-related HMG box 2 (Sox2). MEPM cell pluripotency was retained through activation of the PTEN/Akt/mTOR autophagic signaling pathway. We found that atRA blocked MEPM cell pluripotency to inhibit osteogenic differentiation via miR-106a-5p targeting of PTEN mRNA and subsequent suppression of the PTEN/Akt/mTOR autophagic pathway. ConclusionsIn vitro cultured MEPM cells are ectomesenchymal stem cells that have strong osteogenic differentiation potential, and MEPM pluripotency is regulated by autophagy via the PTEN/AKT/mTOR signaling pathway. atRA disrupts MEPM cell pluripotency through PTEN/AKT/mTOR signaling inactivation where miR-106a-5p targets PTEN mRNA to reduce osteogenic differentiation of MEPM cells and results in the development of cleft palates. Our findings provide new insight into the mechanism underlying the development of cleft palate, and miR-106a-5p may act as a prenatal screening biomarker for cleft palate as well as a new diagnostic and therapeutic target.

developmental biology↗

A Fast Detection Method for Wheat Mould Based on Biophotons

Mould is a common phenomenon in stored wheat. First, mould will decrease the quality of wheat kernels. Second, the mycotoxins metabolized by mycetes are very harmful for humans. Therefore, the fast and accurate examination of wheat mould is vitally important to evaluating its storage quality and subsequent processing safety. Existing methods for examining wheat mould mainly rely on chemical methods, which always involve complex and long pretreatment processes, and the auxiliary chemical materials used in these methods may pollute our environment. To improve the determination of wheat mould, this paper proposed a type of green and nondestructive determination method based on biophotons. The specific implementation process is as follows: first, the ultra-weak luminescence between healthy and mouldy wheat samples are measured repeatedly by a biophotonic analyser, and then, the approximate entropy and multiscale approximate entropy are separately introduced as the main classification features. Finally, the classification performances have been tested using the support vector machine(SVM). The ROC curve of the newly established classification model shows that the highest recognition rate can reach 93.6%, which shows that our proposed classification model is feasible and promising for detecting wheat mould.

microbiology↗

ATPIF1 inactivation promotes antitumor immunity through metabolic reprogramming of CD8+ T cells

Induction of CD8+ T cell activity is a promising strategy in the cancer immunotherapy. In this study, we identified ATP synthase inhibitory factor 1 (ATPIF1) as a potential target in the induction of CD8+ T cell immunity against tumor. Inactivation of ATPIF1 gene in mice promoted the antitumor activity of CD8+ T cells leading to suppression of tumor growth of B16 melanoma and Lewis lung cancer. The phenotype was abolished by deletion of CD8+ T cells in the ATPIF1-KO mice. The tumor infiltrating CD8+ T cells exhibited strong activities in the proliferation, effector and memory as revealed by the single cell RNA sequencing results of CD45+ tumor infiltrating lymphocytes (TILs) isolated from the tumors. The CD8+ T cells expressed more antitumor makers in the tumor microenvironment and in coculture with the tumor cells. The cells had a higher level of glycolysis after the T cell receptor-mediated activation as revealed by the targeted metabolomics assay. The cells exhibited an extra activity of oxidative phosphorylation before the activation as indicated by the oxygen consumption rate. The cells gained capacities in the proliferation, apoptosis resistance and mitophagy in the glucose-limiting environment. These data suggest that inhibition of ATPIF1 activity by gene inactivation rewired the energy metabolism of CD8+ T cells to enhance their immune activities to the tumors. ATPIF1 is a potential molecular target in the induction of antitumor immunity through metabolic reprogramming of CD8+ T cells for the cancer immunotherapy.

immunology↗

S-Trimer, a COVID-19 subunit vaccine candidate, induces protective immunity in nonhuman primates

SARS-CoV-2 is the underlying cause for the COVID-19 pandemic. Like most enveloped RNA viruses, SARS-CoV-2 uses a homotrimeric surface antigen to gain entry into host cells. Here we describe S-Trimer, a native-like trimeric subunit vaccine candidate for COVID-19 based on Trimer-Tag technology. Immunization of S-Trimer with either AS03 (oil-in-water emulsion) or CpG 1018 (TLR9 agonist) plus alum adjuvants induced high-levels of neutralizing antibodies and Th1-biased cellular immune responses in animal models. Moreover, rhesus macaques immunized with adjuvanted S-Trimer were protected from SARS-CoV-2 challenge compared to vehicle controls, based on clinical observations and reduction of viral loads in lungs. Trimer-Tag may be an important new platform technology for scalable production and rapid development of safe and effective subunit vaccines against current and future emerging RNA viruses.

immunology↗