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Huang, Y.

Publications and source records attributed to Huang, Y..

At least 703 records · Page 39Linked to original sources

Attention-wise masked graph contrastive learning for predicting molecular property

MotivationAccurate and efficient prediction of the molecular property is one of the fundamental problems in drug research and development. Recent advancements in representation learning have been shown to greatly improve the performance of molecular property prediction. However, due to limited labeled data, supervised learning-based molecular representation algorithms can only search limited chemical space and suffer from poor generalizability. ResultsIn this work, we proposed a self-supervised learning method, ATMOL, for molecular representation learning and properties prediction. We developed a novel molecular graph augmentation strategy, referred to as attention-wise graph masking, to generate challenging positive samples for contrastive learning. We adopted the graph attention network (GAT) as the molecular graph encoder, and leveraged the learned attention weights as masking guidance to generate molecular augmentation graphs. By minimization of the contrastive loss between original graph and augmented graph, our model can capture important molecular structure and higher-order semantic information. Extensive experiments showed that our attention-wise graph mask contrastive learning exhibited state-of-the-art performance in a couple of downstream molecular property prediction tasks. We also verified that our model pretrained on larger scale of unlabeled data improved the generalization of learned molecular representation. Moreover, visualization of the attention heatmaps showed meaningful patterns indicative of atoms and atomic groups important to specific molecular property.

bioinformatics↗

Multi-task learning uncovers robust translation cis-regulatory features

Many studies have found that sequence in the 5 untranslated regions (UTRs) impacts the translation rate of an mRNA, but the regulatory grammar that underpins this translation regulation remains elusive. Deep learning methods deployed to analyse massive sequencing datasets offer new solutions to motif discovery. However, existing works focused on extracting sequence motifs in individual datasets, which may not be generalisable to other datasets from the same cell type. We hypothesise that motifs that are genuinely involved in controlling translation rate are the ones that can be extracted from diverse datasets generated by different experimental techniques. In order to reveal more generalised cis-regulatory motifs for RNA translation, we develop a multi-task translation rate predictor, MTtrans, to integrate information from multiple datasets. Compared to single-task models, MTtrans reaches a higher prediction accuracy in all the benchmarked datasets generated by various experimental techniques. We show that features learnt in human samples are directly transferable to another dataset in yeast systems, demonstrating its robustness in identifying evolutionarily conserved sequence motifs. Furthermore, our newly generated experimental data corroborated the effect of most of the identified motifs based on MTtrans trained using multiple public datasets, further demonstrating the utility of MTtrans for discovering generalisable motifs. MTtrans effectively integrates biological insights from diverse experiments and allows robust extraction of translation-associated sequence motifs in 5UTR.

bioinformatics↗

Subtyping evaluation of Salmonella Enteritidis using SNP and core genome MLST with nanopore reads

Whole genome sequencing (WGS) for public health surveillance and epidemiological investigation of foodborne pathogens predominantly relies on sequencing platforms that generate short reads. Continuous improvement of long-read nanopore sequencing such as Oxford Nanopore Technologies (ONT) presents a potential for leveraging multiple advantages of the technology in public health and food industry settings, including rapid turnaround and onsite applicability in addition to superior read length. However, evaluation, standardization and implementation of the ONT approach to WGS-based, strain-level subtyping is challenging, in part due to its relatively high base-calling error rates and frequent iterations of sequencing chemistry and bioinformatic analytics. Using an established cohort of Salmonella Enteritidis isolates for subtyping evaluation, we assessed the technical readiness of ONT for single nucleotide polymorphism (SNP) analysis and core-genome multilocus sequence typing (cgMLST) of a major foodborne pathogen. By multiplexing three isolates per flow cell, we generated sufficient sequencing depths under seven hours of sequencing for robust subtyping. SNP calls by ONT and Illumina reads were highly concordant despite homopolymer errors in ONT reads (R9.4.1 chemistry). In silico correction of such errors allowed accurate allelic calling for cgMLST and allelic difference measurements to facilitate heuristic detection of outbreak isolates. Our study established a baseline for the continuously evolving nanopore technology as a viable solution to high quality subtyping of Salmonella, delivering comparable subtyping performance when used standalone or together with short-read platforms.

microbiology↗

UniTVelo: temporally unified RNA velocity reinforces single-cell trajectory inference

The recent breakthrough of single-cell RNA velocity methods brings attractive promises to reveal directed trajectory on cell differentiation, states transition and response to perturbations. However, the existing RNA velocity methods are often found to return erroneous results, partly due to model violation or lack of temporal regularization. Here, we present UniTVelo, a statistical framework of RNA velocity that models the dynamics of spliced and unspliced RNAs via flexible transcription activities. Uniquely, it also supports the inference of a unified latent time across the transcriptome. With ten datasets, we demonstrate that UniTVelo returns the expected trajectory in different biological systems, including hematopoietic differentiation and those even with weak kinetics or complex branches.

bioinformatics↗

FGF signaling promotes precursor spreading for adult adipogenesis in Drosophila

Knowledge of adipogenetic mechanisms is essential to understand and treat conditions affecting organismal metabolism and adipose tissue health. In Drosophila, mature adipose tissue (fat body) exists in larvae and adults. In contrast to the well-known development of the larval fat body from the embryonic mesoderm, adult adipogenesis has remained mysterious. Furthermore, conclusive proof of its physiological significance is lacking. Here, we show that the adult fat body originates from a pool of undifferentiated mesodermal precursors that migrate from the thorax into the abdomen during metamorphosis. Through in vivo imaging, we found that these precursors spread from the ventral midline and cover the inner surface of the abdomen in a process strikingly reminiscent of embryonic mesoderm migration, requiring FGF signaling as well. FGF signaling guides migration dorsally and regulates adhesion to the substrate. After spreading is complete, precursor differentiation involves fat accumulation and cell fusion that produces mature binucleate and tetranucleate adipocytes. Finally, we show that flies where adult adipogenesis is impaired by knock down of FGF receptor Heartless or transcription factor Serpent display ectopic fat accumulation in oenocytes and decreased resistance to starvation. Our results reveal that adult adipogenesis occurs de novo during metamorphosis and demonstrate its crucial physiological role.

developmental biology↗

JiangShi: a widely distributed Mucin-like protein essential for Drosophila development

Epithelia exposed to elements of the environment are protected by a mucus barrier in mammals. This barrier also serves to lubricate during organ movements and to mediate substance exchanges between the environmental milieu and internal organs. A major component of the mucus barrier is a class of glycosylated proteins called Mucin. Mucin and mucin-related proteins are widely present in the animal kingdom. Mucin mis-regulation has been reported in many diseases such as cancers and ones involving the digestive and respiratory tracts. Although the biophysical properties of isolated Mucins have been extensively studied, in vivo models remain scarce for the study of their functions and regulations. Here we characterize the Mucin-like JiangShi (JS) protein and its mutations in the fruit fly Drosophila. JS is an extracellular glycoprotein with domain features reminiscent of mammalian non-membranous Mucins, and one of the most widely distributed Mucin-like proteins studied in Drosophila. Both loss and over-production of JS lead to terminal defects in adult structures and organismal death. Although the physiological function of JS remains poorly defined, we present a genetically tractable model system for the in vivo studies of Mucin-like molecules.

developmental biology↗

Mycn regulates intestinal development through ribosomal biogenesis in a zebrafish model of Feingold syndrome 1

Feingold syndrome type 1, caused by loss-of-function of MYCN, is characterized by varied phenotypes including esophageal and duodenal atresia. However, no adequate model exists for studying the syndromes pathological or molecular mechanisms, nor is there a treatment strategy. Here, we developed a zebrafish Feingold syndrome type 1 model with nonfunctional mycn, which had severe intestinal atresia. Single-cell RNA-seq identified a subcluster of intestinal cells was highly sensitive to Mycn, and impaired cell proliferation decreased the overall number of intestinal cells in the mycn mutant fish. Bulk RNA-seq and metabolomic analysis showed that expression of ribosomal genes was downregulated and amino acid metabolism was abnormal. Ribosomal profiling analysis showed decreases in free 40S, 60S, and 80S ribosome particles, which led to impaired translation in the mutant. Further, both L-leucine and Rheb, which can elevate translation via TOR pathway, rescued the intestinal phenotype of mycn mutant. In summary, by this zebrafish Feingold syndrome type 1 model, we found that disturbance of ribosomal biogenesis and blockage of protein synthesis during development are primary causes of the intestinal defect in Feingold syndrome type 1. Importantly, our work suggests that leucine supplementation may be a feasible and easy treatment option for this disease.

developmental biology↗

Tree diversity effects on productivity depend on mycorrhizae and life strategies in a temperate forest experiment

Tree species are known to predominantly interact either with arbuscular mycorrhizal (AM) or ectomycorrhizal (EM) fungi. However, there is a knowledge gap whether these mycorrhizae differently influence biodiversity-ecosystem functioning (BEF) relationships and whether a combination of both can increase community productivity. In 2015, we established a tree-diversity experiment by growing tree communities with varying species-richness levels (1, 2, or 4 species), and either with AM or EM tree species, or a combination of both. We investigated basal area and annual basal area increment from 2015 to 2020 as proxy for community productivity. We found significant positive relationships between tree species richness and community productivity, which strengthened over time. Further, AM and EM tree species differently influenced productivity; however, there was no overyielding when AM and EM trees grew together. EM tree communities were characterized by low productivity in the beginning, but an increase of increment over time, and showed overall strong biodiversity effects. For AM tree communities the opposite was true. While young trees did not benefit from the presence of the other mycorrhizal type, dissimilar mechanisms underlying BEF relationships in AM and EM trees indicate that maximizing tree and mycorrhizal diversity may increase ecosystem functioning in the long run.

ecology↗

The multi-BRCT domain protein DDRM2 is required for homologous recombination in plants

DNA double-strand breaks (DSBs) are the most toxic DNA damage for cells. Homologous recombination (HR) is a precise DSB repair mechanism as well as a basis for gene targeting using genome-editing techniques. Despite the importance of HR, the HR mechanism in plants is poorly understood. In a genetic screen for DNA Damage Response Mutants (DDRMs), we find that the Arabidopsis ddrm2 mutant is hypersensitive to DSB-inducing reagents. DDRM2 encodes a protein with four BRCA1 C-terminal (BRCT) domains and is highly conserved in plants including the earliest land plant linage, bryophytes. The plant-specific transcription factor SOG1 binds to the promoter of DDRM2 and activates its expression, suggesting that DDRM2 is a direct target of SOG1. In consistence, the expression of DDRM2 is induced by DSBs in a SOG1-dependent manner. Epistasis analysis indicates that DDRM2 functions downstream of SOG1. Similar to the sog1 mutant, the ddrm2 mutant shows dramatically reduced HR efficiency. Our study suggests that the SOG1-DDRM2 module is required for HR, providing new insights into the HR mechanisms in plants and a potential target for improving the efficiency of gene targeting. One Sentence SummaryA genetic screen in Arabidopsis reveals that the multi-BRCT domain protein DDRM2 is required for homologous recombination and is targeted by the master DNA damage response regulator SOG1.

plant biology↗

An environmentally ultrasensitive fluorine-19 NMR probe for monitoring protein conformational equilibria

Limited chemical shift dispersion represents a significant barrier to studying multi-state equilibria of large membrane proteins by 19F NMR. We describe a novel monofluoroethyl 19F probe that dramatically increases the chemical shift dispersion. The improved conformational sensitivity and line shape enable the detection of previously unresolved states in 1D NMR spectra of a 134 kDa membrane transporter. Changes in the populations of these states in response to ligand binding, mutations, and temperature correlate with population changes of distinct conformations in structural ensembles determined by single-particle cryo-electron microscopy. Thus, 19F NMR can guide sample preparation to discover and visualize novel conformational states and facilitate image analysis and 3D classification.

biophysics↗

DCATS: differential composition analysis for complex single-cell experimental designs

Differential composition analysis - the identification of cell types that have statistically significantly change in abundance between multiple experimental conditions - is one of the most common tasks in single cell omic data analysis. However, it remains challenging to perform differential composition analysis in the presence of complex experimental designs and uncertainty in cell type assignment. Here, we introduce a statistical model and an open source R package, DCATS, for differential composition analysis based on a beta-binomial regression framework that addresses these challenges. Our empirical evaluation shows that DCATS consistently maintain high sensitively and specificity compared to state-of-the-art methods.

bioinformatics↗

Global Spatial Transcriptome of Macaque Brain at Single-Cell Resolution

Global profile of gene expression at single-cell resolution remains to be determined for primates. Using a recently developed technology ("Stereo-seq"), we have obtained a comprehensive single-cell spatial transcriptome map at the whole-brain level for cynomolgus monkeys, with [~]600 genes per cell for 10 m-thick coronal sections (up to 15 cm2 in size). Large-scale single-nucleus RNA-seq analysis for [~]1 million cells helped to identify cell types corresponding to Stereo-seq gene expression profiles, providing a 3-D cell type atlas of the monkey brain. Quantitative analysis of Stereo-seq data revealed molecular fingerprints that mark distinct neocortical layers and subregions, as well as domains within subcortical structures including hippocampus, thalamus, striatum, cerebellum, hypothalamus and claustrum. Striking whole-brain topography and coordinated patterns were found in the expression of genes encoding receptors and transporters for neurotransmitters and neuromodulators. These results pave the way for cellular and molecular understanding of organizing principles of the primate brain.

cell biology↗

STOmicsDB: a database of Spatial Transcriptomic data

Recent technological development in spatial transcriptomics allows researchers to measure gene expression of cells and their spatial locations at the almost single-cell level, which generates detailed biological insight into biological processes. However, specialized spatial transcriptomics databases are rare. Here, we present the Spatial TranscriptOmics DataBase (STOmicsDB), a user-friendly database with multifunctions including search of relevant publications and tools, public dataset visualization, customized specialized databases, new data archive, and online analysis. The current version of STOmicsDB consists of 141 curated spatial transcript datasets covering 12 species, and includes 5,618 spatial multi-omics publications and 674 tools. STOmicsDB is freely accessible at https://db.cngb.org/stomics/.

genomics↗

The maternal X chromosome impairs cognition and accelerates brain aging through epigenetic modulation in female mice

Female mammalian cells harbor two X chromosomes, one of maternal and one of paternal origin. During development, one X randomly inactivates1-4. This renders either the maternal or paternal X active, causing X mosaicism that varies among individual females, with some showing considerable or complete skew in the general female population5-7. Parent-of-X-origin can modify epigenetics via DNA methylation8, 9 and possibly gene expression; thus, mosaicism could buffer dysregulated processes in aging and disease. However, whether X skewing - or its mosaicism - alters functions in females is largely unknown. Here we tested whether skew toward the maternal X (Xm) influences key functions of the body. Among cardiac, bone, metabolic, and brain functions, Xm selectively impaired cognition in female mice throughout the lifespan. Cognitive deficits were accompanied by Xm-mediated acceleration of biologic or epigenetic aging of the female hippocampus, a key center for learning and memory. Xm showed epigenetic imprinting of several genes within hippocampal neurons, suggesting silenced cognitive loci. Thus, the maternal X chromosome impaired cognition, accelerated brain aging, and silenced genes. Understanding how the maternal X impairs brain function could lead to new understanding of female heterogeneity in cognitive heath and to X chromosome-derived pathways against cognitive deficits and brain aging.

neuroscience↗

Species-specific chromatin landscape determines how transposable elements shape genome evolution

Transposable elements (TEs) are selfish genomic parasites that increase their copy number at the expense of host fitness. The "success," or genome-wide abundance, of TEs differs widely between species. Deciphering the causes for this large variety in TE abundance has remained a central question in evolutionary genomics. We previously proposed that species-specific TE abundance could be driven by the inadvertent consequences of host-direct epigenetic silencing of TEs--the spreading of repressive epigenetic marks from silenced TEs into adjacent sequences. Here, we compared this TE-mediated "epigenetic effect" in six species in the Drosophila melanogaster subgroup to dissect step-by-step the role of such effect in determining genomic TE abundance. We found that TE-mediated spreading of repressive marks is prevalent and substantially varies across and even within species. While this TE-mediated effect alters the epigenetic states of adjacent genes, we surprisingly discovered that the transcription of neighboring genes could reciprocally impact this spreading. Importantly, our multi- species analysis provides the power and appropriate phylogenetic resolution to connect species-specific host chromatin regulation, TE-mediated epigenetic effects, the strength of natural selection against TEs, and genomic TE abundance unique to individual species. Our findings point towards the importance of host chromatin landscapes in shaping genome evolution through the epigenetic effects of a selfish genetic parasite.

genomics↗

iPheGWAS : an intelligent computational framework to integrate and visualise genome-phenome wide association studies

Estimating the genetic correlations by LDSC is computationally demanding and visualising multiple GWAS results along with their genetic relationships is restricted. This study developed iPheGWAS, a novel approach which applied hierarchical clustering to GWAS summary statistics to (i) calculate their genetic relatedness, and (ii) enable three-dimensional visualisation of multiple ordered GWAS plots. Simulation and real-world data analysis demonstrated that when investigating genetic relationships among multiple phenotypes, iPheGWAS can deliver comparable results with LDSC but with 8 times faster computational speed. It can also provide novel findings in studying genetically-correlated comorbidities, such as mental illness and rheumatoid arthritis.

bioinformatics↗

Proteogenomics refines the molecular classification of chronic lymphocytic leukemia

Cancer heterogeneity at the proteome level may explain differences in therapy response and prognosis beyond the currently established genomic and transcriptomic based diagnostics. The relevance of proteomics for disease classifications remains to be established in clinically heterogeneous cancer entities such as chronic lymphocytic leukemia (CLL). Here, we characterized the proteome and transcriptome in-depth alongside genetic and ex-vivo drug response profiling in a clinically well annotated CLL discovery cohort (n= 68). Unsupervised clustering of the proteome data revealed six subgroups. Five of these proteomic groups were associated with genetic features, while one group was only detectable at the proteome level. This new group was characterized by accelerated disease progression, high spliceosomal protein abundances associated with aberrant splicing, and low B cell receptor signaling protein abundances (ASB-CLL). We developed classifiers to identify ASB-CLL based on its characteristic proteome or splicing signature in two independent cohorts (n= 165, n= 169) and confirmed that ASB-CLL comprises about 20 % of CLL patients. The inferior overall survival observed in ASB-CLL was independent of both TP53- and IGHV mutation status. Our multi-omics analysis refines the classification of CLL and highlights the potential of proteomics to improve cancer patient stratification beyond genetic and transcriptomic profiling. Single sentence summaryWe performed the largest proteogenomic analysis of CLL, linked proteomic profiles to clinical outcomes, and discovered a new poor outcome subgroup (ASB-CLL).

cancer biology↗

Balancing activation and costimulation of CAR tunes signaling dynamics and enhances therapeutic potency

BackgroundPrimary human T cells engineered with chimeric antigen receptors (CARs) ex vivo can be adoptively transferred to treat cancer. CD19-targeting CAR with CD28 costimulatory domain and CD3{zeta} activation domain have been approved by the US FDA for treating B cell malignancies. MethodsHere we generated mutation of immunorecpetor tyrosine-based activation motifs (ITAMs) in CD3{zeta}, namely 1XX CAR, which altered the balance of activation and costimulation. Next we investigated whether 1XX design could enhance therapeutic potency against solid tumors. We constructed both CD19- and AXL-specific 1XX CARs and compared their in vitro and in vivo functions with their WT counterparts. ResultsEven though 1XX CARs decreased cytotoxicity against tumor cells in vitro, they showed better anti-tumor efficacy in both pancreatic and melanoma mouse models. Detailed analysis revealed that 1XX CAR-T cells proliferated more in response to antigen stimulation in vitro, persisted longer in vivo and had higher percentage of central memory cells. As 1XX modification directly calibrates CAR activation potential, we utilized fluorescence resonance energy transfer (FRET)-based biosensor to monitor signaling dynamics downstream of CARs. Decreased ITAM numbers in 1XX resulted in similar ZAP70 activation, while 1XX induced higher Ca2+ elevation and faster Erk activation than WT CAR, which may contribute to the better therapeutic potency of 1XX. ConclusionsOur results established the surpiosity of 1XX against two targets in different solid tumor models and shed light on the underlying molecular mechanism of CAR signaling, paving the way for the clinical application of 1XX CARs against solid tumors.

immunology↗