Biology subjects

Kong, S.

Publications and source records attributed to Kong, S..

At least 37 records · Page 2Linked to original sources

bioRxiv2023

Single extracellular vesicle imaging and computational analysis identifiesinherent architectural heterogeneity

Evaluating the heterogeneity of extracellular vesicles (EVs) is crucial for unraveling their complex actions and biodistribution. Here, we identify consistent architectural heterogeneity of EVs using cryogenic transmission electron microscopy (cryo-TEM) which has an inherent ability to image biological samples without harsh labeling methods and while preserving their native conformation. Imaging EVs isolated using different methodologies from distinct sources such as cancer cells, normal cells, and body fluids, we identify a structural atlas of their dominantly consistent shapes. We identify EV architectural attributes by utilizing a segmentation neural network model. In total, 7,576 individual EVs were imaged and quantified by our computational pipeline. Across all 7,576 independent EVs, the average eccentricity was 0.5366, and the average equivalent diameter was 132.43 nm. The architectural heterogeneity was consistent across all sources of EVs, independent of purification techniques, and compromised of single spherical (S. Spherical), rod-like or tubular, and double shapes. This study will serve as a reference foundation for high-resolution EV images and offer insights into their potential biological impact.

bioengineering↗

bioRxiv2023

Tradeoff Between Speed and Robustness in Primordium Initiation Mediated by Auxin-CUC1 Interaction

Robustness is the reproducible development of a phenotype despite stochastic noise. It often involves tradeoffs with other performance metrics, but the mechanisms underlying such tradeoffs were largely unknown. An Arabidopsis flower robustly develops four sepals from four precisely positioned auxin maxima. The development related myb-like 1 (drmy1) mutant generates noise in auxin signaling that disrupts robustness in sepal initiation. Here, we found that increased expression of CUP-SHAPED COTYLEDON1 (CUC1), a boundary specification transcription factor, in drmy1 underlies this loss of robustness. CUC1 surrounds and amplifies stochastic auxin noise in drmy1 to form variably positioned auxin maxima and sepal primordia. Removing CUC1 from drmy1 provides time for noisy auxin signaling to resolve into four precisely positioned auxin maxima, restoring robust sepal initiation. However, removing CUC1 decreases auxin maxima intensity and slows down sepal initiation. Thus, CUC1 increases morphogenesis speed but impairs robustness against auxin noise. Further, using a computational model, we found that the observed phenotype can be explained by the effect of CUC1 in repolarizing PIN FORMED1 (PIN1), a polar auxin transporter. Lastly, our model predicts that reducing global growth rate improves developmental robustness, which we validated experimentally. Thus, our study illustrates a tradeoff between speed and robustness during development.

developmental biology↗

bioRxiv2023

GametesOmics: A Comprehensive Multi-Omics Database for Exploring the Gametogenesis in Humans and Mice

Gametogenesis plays an important role in the reproduction and evolution of species. The transcriptomic and epigenetic alterations in this process can influence the reproductive capacity, fertilization, and embryonic development. The rapidly increasing single-cell studies have provided valuable multi-omics resources. However, data from different layers and sequencing platforms have not been uniformed and integrated, which greatly limits their use for exploring the molecular mechanisms that underlie oogenesis and spermatogenesis. Here, we developed GametesOmics, a comprehensive database that integrated the data of gene expression, DNA methylation, and chromatin accessibility during oogenesis and spermatogenesis in humans and mice. GametesOmics provides a user-friendly website and various tools, including Search and Advanced Search for querying the expression and epigenetic modification of each gene; Analysis Tools with Differentially Expressed Gene (DEG) analysis for identifying DEGs, Correlation analysis for demonstrating the genetic and epigenetic changes, Visualization for displaying single-cell cluster and screening marker genes as well as master transcription factors (TFs), and MethylView for studying the genomic distribution of epigenetic modifications. GametesOmics also provides Genome Browser and Orthologs for tracking and comparing gene expression, DNA methylations, as well as chromatin accessibilities between humans and mice. GametesOmics offers a comprehensive resource for biologists and clinicians to decipher the cell fate transition in germ cell development, and can be accessed at http://gametesomics.cn/.

bioinformatics↗

bioRxiv2023

Predicting human microbe-drug associations via graph attention network with multiple kernel fusion

Microbial dysregulation may lead to the occurrence of diseases, and using microbe and drug data to infer the microbe-drug association has attracted extensive attention. There have been many studies to build association prediction models, but most of them are through biological experiments, which are time-consuming and expensive. Therefore, it is necessary to develop a computational method focusing on microbe-drug spatial information to predict the microbe-drug associations. In this work, we use the biological information to construct heterogeneous networks of drugs and microbes. We propose a new method based on Multiple Kernel fusion on Graph Attention Network (GAT) to predict human microbe-drug associations, called GATMDA. Our method extracts multi-layer features based on GAT which can learn the embedding of microbes and drugs on each layer and achieve the purpose of extracting multiple information. We further fuse multiple kernel matrices based on average weighting method. Finally, combined kernel in the microbe space and drug space are used to infer microbe-drug associations. Compared with eight state-of-the-art methods, our method receives the highest AUC and AUPR on MDAD and aBiofilm dataset. Case studies for Human immunodeficiency virus 1 (HIV-1) and adenovirus further confirm the effectiveness of GATMDA in identifying potential microbe-drug associations.

bioinformatics↗

bioRxiv2023

Deep learning approaches to the phylogenetic placement of extinct pollen morphotypes

The phylogenetic interpretation of pollen morphology is limited by our inability to recognize the evolutionary history embedded in pollen features. Deep learning offers tools for connecting morphology to phylogeny. Using neural networks, we developed an explicitly phylogenetic toolkit for analyzing the overall shape, internal structure, and texture of a pollen grain. Our analysis pipeline determines whether testing specimens are from unknown species based on uncertainty estimates. Features of novel specimens are passed to a multi-layer perceptron network trained to transform these features into predicted phylogenetic distances from known taxa. We used these predicted distances to place specimens in a phylogeny using Bayesian inference. We trained and evaluated our models using optical superresolution micrographs of 30 Podocarpus species. We then used trained models to place nine fossil Podocarpidites specimens within the phylogeny. In doing so, we demonstrate that the phylogenetic history encoded in pollen morphology can be recognized by neural networks and that deep-learned features can be used in phylogenetic placement. Our approach makes extinction and speciation events that would otherwise be masked by the limited taxonomic resolution of the fossil pollen record visible to palynological analysis. Significance StatementMachine learned features from deep neural networks can do more than categorize and classify biological images. We demonstrate that these features can also be used to quantify morphological differences among pollen taxa, discover novel morphotypes, and place fossil specimens on a phylogeny using Bayesian inference. Deep learning can be used to characterize and identify and morphological features with evolutionary significance. These features can then be used to infer phylogenetic distance. This approach fundamentally changes how fossil pollen morphology can be interpreted, allowing greater evolutionary inference of fossil pollen specimens. The analysis framework, however, is not specific to pollen and can be generalized to other taxa and other biological images.

paleontology↗

bioRxiv2023

Genome-wide identification of silencers in human cells

Transcriptional regulation is a complex process that is controlled by a variety of factors, including enhancers and silencers. Silencers, also known as repressor elements, play a crucial role in the fine-tuning of gene expression by inhibiting or suppressing transcription in the human genome. Although significant progresses have been made, genome-wide silencer research is still in its early stages. Here, we used a genome-wide method called massively parallel reporter assays (MPRAs) to identify silencers in three human cell lines: K562, LNCap, and HEK293T. We identified 739,434, 643,484, and 491,952 silencer regions in these cell lines, respectively. We found that most of the silencers we identified had inhibitory activity and significantly enriched inhibitory motifs. These results confirm that silencers are ubiquitous in the human genome and play an important role in regulating gene expression. Therefore, our study provides a general strategy for genome-wide functional identification of silencer elements. This information could be used to better understand the mechanisms of gene regulation and to develop new therapeutic strategies for diseases that are caused by dysregulation of gene expression.

genomics↗

bioRxiv2023

A Likelihood Ratio Test for Hybridization Under the Multispecies Coalescent

Several methods have been developed to carry out a statistical test for hybridization at the species level, including the ABBA-BABA test and HyDe. Here, we propose a new method for detecting hybridization and quantifying the extent of hybridization. Our test computes the likelihood of a species tree that is possibly subject to hybridization using site pattern frequencies from genomic-scale datasets under the multispecies coalescent. To do this, we extend the calculation of the likelihood for site pattern frequency data for the 4-taxon symmetric and asymmetric species trees proposed in Chifman and Kubatko (2015) by incorporating an inheritance parameter, resulting in efficient computation of the likelihood under a scenario of hybridization. We use this likelihood computation to construct a likelihood ratio test that a given species is a hybrid of two parental species. Simulations demonstrate that our test is more powerful than existing tests of hybridization, including HyDe, and that it achieves the desired type I error rate. We apply the method to two empirical data sets, one for which hybridization is believed to have occurred and one for which previous methods have failed to detect hybridization.

evolutionary biology↗

bioRxiv2023

DRMY1 promotes robust morphogenesis by sustaining translation of a hormone signaling protein

Robustness is the invariant development of phenotype despite environmental changes and genetic perturbations. In the Arabidopsis flower bud, four sepals robustly initiate and grow to constant size to enclose and protect the inner floral organs. We previously characterized the mutant development related myb-like1 (drmy1), where 3-5 sepals initiate variably and grow to different sizes, compromising their protective function. The molecular mechanism underlying this loss of robustness was unclear. Here, we show that drmy1 has reduced TARGET OF RAPAMYCIN (TOR) activity, ribosomal content, and translation. Translation reduction decreases the protein level of ARABIDOPSIS RESPONSE REGULATOR7 (ARR7) and ARABIDOPSIS HISTIDINE PHOSPHOTRANSFER PROTEIN 6 (AHP6), two cytokinin signaling inhibitors that are normally rapidly produced before sepal initiation. The resultant upregulation of cytokinin signaling disrupts robust auxin patterning and sepal initiation. Our work shows that the homeostasis of translation, a ubiquitous cellular process, is crucial for the robust spatiotemporal patterning of organogenesis.

developmental biology↗

bioRxiv2022

Inference of Phylogenetic Networks from Sequence Data using Composite Likelihood

While phylogenies have been essential in understanding how species evolve, they do not adequately describe some evolutionary processes. For instance, hybridization, a common phenomenon where interbreeding between two species leads to formation of a new species, must be depicted by a phylogenetic network, a structure that modifies a phylogeny by allowing two branches to merge into one, resulting in reticulation. However, existing methods for estimating networks are computationally expensive as the dataset size and/or topological complexity increase. The lack of methods for scalable inference hampers phylogenetic networks from being widely used in practice, despite accumulating evidence that hybridization occurs frequently in nature. Here, we propose a novel method, PhyNEST (Phylogenetic Network Estimation using SiTe patterns), that estimates phylogenetic networks directly from sequence data. PhyNEST achieves computational efficiency by using composite likelihood as well as accuracy by using the full genomic data to incorporate all sources of variability, rather than first summarizing the data by estimating a set of gene trees, as is required by most of the existing methods. To efficiently search network space, we implement both hill-climbing and simulated annealing algorithms. Simulation studies show that PhyNEST can accurately estimate parameters given the true network topology and that it has comparable accuracy to two popular methods that use composite likelihood and a set of gene trees as input, implemented in SNaQ and PhyloNet. For datasets with a large number of loci, PhyNEST is more efficient than SNaQ and PhyloNet when considering the time required for gene tree estimation. We applied PhyNEST to reconstruct the evolutionary relationships among Heliconius butterflies and Papionini primates, characterized by hybrid speciation and widespread introgression, respectively. PhyNEST is implemented in an open-source Julia package and publicly available at https://github.com/sungsik-kong/PhyNEST.jl.

evolutionary biology↗

bioRxiv2022

Gaq-PKD/PKCμ regulates the IkB transcription to limit the NF-kB mediated inflammatory response essential for early pregnancy

Decidualization, denoting the transformation of endometrial stromal cells into specialized decidual cells, is a prerequisite for normal embryo implantation and a successful pregnancy in human. Here we demonstrated that knockout of Gaq lead to an aberrantly enhanced inflammatory state during decidualization. Furthermore, we showed that deficiency of Gaq resulted in over-activation of nuclear factor (NF)-{kappa}B signaling, due to the decreased expression of NF{kappa}BIA, which encode the I{kappa}B protein and is the negative regulator for NF{kappa}B. Mechanistically, Gaq deficiency decreased the PKD/PKC phosphorylation levels, so leading to attenuated HDAC5 phosphorylation and thus its nuclear export. Aberrantly high level of nuclear HADC5 retarded histone acetylation to inhibit NF{kappa}BIA transcription during decidualization. Consistently, pharmacological activation of the PKD/PKC or inhibition of the HDAC5 signaling restored the inflammatory state and proper decidual response. Finally, we disclosed that over-active inflammatory state in Gaq deficient decidua deferred the blastocyst hatching and adhesion in vitro, and the decidual expression of Gq was significantly lower in women with recurrent pregnancy loss compared with normal pregnancy. In brief, we showed here that Gq as a key regulator of the inflammatory cytokines expression and decidual homeostasis in response to differentiation cues, which is required for successful implantation and early pregnancy.

cell biology↗

bioRxiv2022

Topological incongruence between Median-Joining Networks and Bayesian inference phylogenies

1Inferring phylogenies among intraspecific individuals often yields unresolved relationships (i.e., polytomies). Consequently, methods that compute distance-based abstract networks, like Median-Joining Networks (MJNs), are thought to be more appropriate tools for reconstructing such relationships than traditional trees. MJNs visualize all routes of relationships in the form of cycles, if needed, when traditional approaches cannot resolve them. However, the MJN method is a distance-based phenetic approach that does not involve character transformations and makes no reference to ancestor-descendant relationships. Although philosophical and theoretical arguments challenging the implication that MJNs reflect phylogenetic signal in the traditional sense have been presented elsewhere, an empirical comparison with a character-based approach is needed given the increasing popularity of MJN analysis in evolutionary biology. Here, we use the conservative Approximately Unbiased (AU) test to compare 85 cases of branching patterns of cycle-free MJNs and Bayesian Inference (BI) phylogenies using datasets from 55 empirical studies. By rooting the MJN analyses to provide directionality, analyses find substantial disagreement between computed MJNs and posterior distributions on BI phylogenies. The branching patterns in MJNs and BI phylogenies show significantly different relationships in 37.6% of cases. Among the relationships that were not significantly different, 96.2% show different sets of relationships. Our results indicate that the two methods provide different measures of relatedness in a phylogenetic sense. Finally, our analyses also support previous observations of the statistical hypothesis testing by reconfirming the over-conservativeness of the Shimodaira-Hasegawa test versus the AU test.

evolutionary biology↗

bioRxiv2022

The Phosphate Deprivation Response is Mediated by an Interaction between Brassinosteroid Signaling and Zinc in Tomato

Phosphate is a necessary macronutrient for basic biological processes, plant growth, and agriculture. Plants modulate their root system architecture and cellular processes to adapt to phosphate deprivation albeit with a growth penalty. Excess application of phosphate fertilizer, on the other hand, leads to eutrophication and has a negative environmental impact. Moreover, phosphate mined from rock reserves is a finite and non-recyclable resource and its levels are nearing complete depletion. Here, we show that Solanum pennellii, a wild relative of tomato, is partially insensitive to phosphate deprivation. Furthermore, it mounts a constitutive response under phosphate sufficiency. We demonstrate that activated brassinosteroid signaling through a tomato BZR1 ortholog gives rise to the same constitutive phosphate deficiency response, which is dependent on zinc over-accumulation. Collectively, these results reveal an additional strategy by which plants can adapt to phosphate starvation.

plant biology↗

bioRxiv2022

Infant antibody repertoires during the first two years of influenza vaccination

The first encounter with influenza virus biases later immune responses. This "immune imprinting", formerly from infection within a few years of birth, is in the U.S. now largely from immunization with a quadrivalent, split vaccine (IIV4). In a pilot study of IIV4 imprinting, we characterized, by single-B-cell cultures, NextGen sequencing, and plasma antibody proteomics, the primary antibody responses to influenza in two infants during their first two years of seasonal influenza vaccination. One infant, who received only a single vaccination in Year 1, contracted an influenza B (IBV) infection between the two years, allowing us to compare imprinting by infection and vaccination. That infant had a shift in hemagglutinin (HA)-reactive B-cell specificity from largely influenza A (IAV)-specific in Year 1 to IBV-specific in Year 2, both before and after vaccination. HA-reactive B cells from the other infant maintained a more evenly distributed specificity. In Year 2, class-switched HA-specific B cell IGHV somatic hypermutation (SHM) levels reached average levels seen in adults. The HA-reactive plasma antibody repertoires of both infants comprised a relatively small number of antibody clonotypes, with one or two very abundant clonotypes. Thus, after the Year 2 boost, both infants had overall B cell profiles that resembled those of adult controls. ImportanceInfluenza virus is a moving target for the immune system. Variants emerge that escape protection from antibodies elicited by a previously circulating variant ("antigenic drift"). The immune system usually responds to a drifted influenza virus by mutating existing antibodies rather than by producting entirely new ones. Thus, immune memory of the earliest influenza exposure has a major influence on later responses to infection or vaccination ("immune imprinting"). In the many studies of influenza immunity in adult subjects, imprinting has been from an early infection, since only in the past two decades have infants received influenza immunizations. The work reported in this paper is a pilot study of imprinting in two infants by the flu vaccine, which they received before experiencing an influenza infection. The results suggest that a quadrivalent (four-subtype) vaccine may provide an immune imprint less dominated by one subtype than does a monovalent infection.

immunology↗

bioRxiv2022

Spatial compartmentalization of signalling imparts source-specific functions on secreted factors

Efficient regeneration requires multiple cell types acting in a coordination. To better understand the intercellular networks involved and how they change when regeneration fails, we profiled the transcriptome of hematopoietic, stromal, myogenic, and endothelial cells over 14 days following acute muscle damage. A time-resolved computational model of interactions was generated, and VEGFA-driven endothelial engagement was identified as a key differentiating feature in models of successful and failed regeneration. In addition, it revealed that the majority of secreted signals, including VEGFA, are simultaneously produced by multiple cell types. To test whether the cellular source of a factor determines its function, we deleted VEGFA from two cell types residing in close proximity, stromal and myogenic progenitors. By comparing responses to different types of damage, we found that myogenic and stromal VEGFA have distinct functions in regeneration. This suggests that spatial compartmentalization of signaling plays a key role in intercellular communication networks. HighlightsO_LILigand-receptor signaling redundancy during skeletal muscle regeneration C_LIO_LIInflammatory cells, and muscle and fibro/adipogenic progenitors produce VEGFA C_LIO_LIVEGFA from muscle progenitors control their proliferation after muscle damage C_LIO_LIVEGFA from FAP controls angiogenesis only after ischemic damage C_LI eTOC blurbGroppa et al. performed a novel time-resolved bioinformatics analysis that revealed extensive ligand-receptor redundancy among the cell types contributing to skeletal muscle regeneration. They focused on one of these pathways, and showed that VEGFA from different cell types has distinct roles in regeneration.

cell biology↗

bioRxiv2021

pGlycoQuant with a deep residual network for precise and minuscule-missing-value quantitative glycoproteomics enabling the functional exploration of site-specific glycosylation

Interpreting large-scale glycoproteomic data for intact glycopeptide identification has been tremendously advanced by software tools. However, software tools for quantitative analysis of intact glycopeptides remain lagging behind, which greatly hinders exploring the differential expression and functions of site-specific glycosylation in organisms. Here, we report pGlycoQuant, a generic software tool for accurate and convenient quantitative intact glycopeptide analysis, supporting both primary and tandem mass spectrometry quantitation for multiple quantitative strategies. pGlycoQuant enables intact glycopeptide quantitation with very low missing values via a deep residual network, thus greatly expanding the quantitative function of several powerful search engines, currently including pGlyco 2.0, pGlyco3, Byonic and MSFragger-Glyco. The pGlycoQuant-based site-specific N-glycoproteomic study conducted here quantifies 6435 intact N-glycopeptides in three hepatocellular carcinoma cell lines with different metastatic potentials and, together with in vitro molecular biology experiments, illustrates core fucosylation at site 979 of the L1 cell adhesion molecule (L1CAM) as a potential regulator of HCC metastasis. pGlycoQuant is freely available at https://github.com/expellir-arma/pGlycoQuant/releases/. We have demonstrated pGlycoQuant to be a powerful tool for the quantitative analysis of site-specific glycosylation and the exploration of potential glycosylation-related biomarker candidates, and we expect further applications in glycoproteomic studies.

systems biology↗

bioRxiv2021

SOX4 facilitates PGR protein stability and FOXO1 expression conducive for human endometrial decidualization

The establishment of receptive endometrium in human necessitates appropriate decidualization of stromal cells, which involves steroids regulated periodic transformation of endometrial stromal cells during menstrual cycle. Insufficient decidualization of endometrium contributes to not only the failure of embryo implantation and unexplained infertility, but also the occurrence of recurrent spontaneous abortion, intrauterine growth retardation, preeclampsia, and other clinical gynecological diseases. However, the potential molecular regulatory mechanism underlying the initiation and maintenance of decidualization in humans is yet to be fully elucidated. In this investigation, we document that SOX4 is a key regulator of human endometrial stromal cells (hESCs) decidualization by directly regulating PRL and FOXO1 expression as revealed by whole genomic binding of SOX4 assay and RNA-Seq. Besides, our immunoprecipitation and mass spectrometry results unravel that SOX4 modulates progesterone receptor (PGR) stability through repressing E3 ubiquitin ligase HERC4 mediated degradation. More importantly, we provide evidence that dysregulated SOX4-HERC4-PGR axis is a potential cause of defective decidualization and recurrent implantation failure (RIF) in IVF patients. In summary, this study evidences that SOX4 is a new and critical regulator for human endometrial decidualization, and provides insightful information for the pathology of decidualization-related infertility and will pave the way for pregnancy improvement.

physiology↗

bioRxiv2021

The Evolutionary History of Small RNAs in the Solanaceae

The Solanaceae or "nightshade" family is an economically important group that harbors a remarkable amount of diversity. To gain a better understanding of how the unique biology of the Solanaceae relates to the familys small RNA genomic landscape, we downloaded over 255 publicly available small RNA datasets that comprise over 2.6 billion reads of sequence data. We applied a suite of computational tools to predict and annotate two major small RNA classes: (1) microRNAs (miRNAs), typically 20-22 nt RNAs generated from a hairpin precursor and functioning in gene silencing, and (2) short interfering RNAs (siRNAs), including 24-nt heterochromatic siRNAs (hc-siRNAs) typically functioning to repress repetitive regions of the genome via RNA-directed DNA methylation, as well as secondary phased siRNAs (phasiRNAs) and trans-acting siRNAs (tasiRNAs) generated via miRNA-directed cleavage of a Pol II-derived RNA precursor. Our analyses described thousands of small RNA loci, including poorly-understood clusters of 22-nt siRNAs that accumulate during viral infection. The birth, death, expansion, and contraction of these small RNA loci are dynamic evolutionary processes that characterize the Solanaceae family. These analyses indicate that individuals within the same genus share similar small RNA landscapes, whereas comparisons between distinct genera within the Solanaceae reveal relatively few commonalities. ONE-SENTENCE SUMMARYWe use over 255 publicly-available small RNA datasets to characterize the small RNA landscape for the Solanaceae family.

plant biology↗

bioRxiv2021

GproDIA enables data-independent acquisition glycoproteomics with comprehensive statistical control

Large-scale profiling of intact glycopeptides is critical but challenging in glycoproteomics. Data independent acquisition (DIA) is an emerging technology with deep proteome coverage and accurate quantitative capability in proteomics studies, but is still in the early stage of development in the field of glycoproteomics. We propose GproDIA, a framework for the proteome-wide characterization of intact glycopeptides from DIA data with comprehensive statistical control by a 2-dimentional false discovery rate approach and a glycoform inference algorithm, enabling accurate identification of intact glycopeptides using wide isolation windows. We further adapt a semi-empirical spectrum prediction strategy to expand the coverage of spectral libraries of glycopeptides. We benchmark our method for N-glycopeptide profiling on DIA data of yeast and human serum samples, demonstrating that DIA with GproDIA outperforms the data dependent acquisition (DDA) based methods for glycoproteomics in terms of capacity and data completeness of identification, as well as accuracy and precision of quantification. We expect that this work can provide a powerful tool for glycoproteomic studies.

bioinformatics↗