Biology subjects

Huang, J.

Publications and source records attributed to Huang, J..

At least 397 records · Page 22Linked to original sources

bioRxiv2022

Prioritizing prognostic-associated subpopulations and individualized recurrence risk signatures from single-cell transcriptomes of colorectal cancer

Colorectal cancer (CRC) is one of the most common gastrointestinal malignancies. There are few recurrence risk signatures for CRC patients. Single-cell RNA-sequencing (scRNA-seq) provides a high resolution platform for prognostic signature detection. However, scRNA-seq is not practical in large cohorts due to its high cost and most single-cell experiments lack clinical phenotype information. Few studies have been reported to use external bulk transcriptome with survival time to guide the detection of key cell subtypes in scRNA-seq data. We proposed a data analysis framework to prioritize prognostic-associated subpopulations based on relative expression orderings (REOs). Cell type specific gene pairs (C-GPs) were identified to evaluate prognostic value for each cell type. We found REOs-based signatures could accurately classify most cell subtypes. C-GPs achieves higher precision compared with four current methods. Moreover, we developed single-cell gene pair signatures to predict recurrence risk for patients individually. Fibro_SGK1 cells and IgA+ IGLC2+ B cells were novel prognostic-associated subpopulations. A user-friendly toolkit, scRankXMBD (https://github.com/xmuyulab/scRank-XMBD), was developed to enable implementation of this framework. Our work facilitate the application of the rank-based method in scRNA-seq data for prognostic biomarker discovery and precision oncology.

bioinformatics↗

bioRxiv2022

The metabolite alpha-ketobutyrate increases health and life spans by activating AMPK

Aging is a complex process that is directly related to human health and disease. The extraordinary finding that aging is malleable, as shown in model organisms whose life and health spans are extended by specific gene mutations or dietary or pharmacological perturbations 1-3, has offered enormous hope for our understanding and treatment of aging and related diseases. Although many molecules have been identified that can extend the lifespan of model organisms, few have been shown to alleviate age-related symptoms or illness in mammals 4. Here we show that supplementation with the endogenous metabolite -ketobutyrate (-KB) increases the lifespan of adult C. elegans. Using Gelfree DARTS-PROTOMAP, we identified microtubule-actin cross-linking factor (MACF1) that was protected against proteolysis in the presence of -KB. MACF1 belongs to the spectraplakin family of giant, evolutionarily conserved proteins with versatile functions 5, but their link to longevity regulation has not been explored. -KBs longevity effect in C. elegans is abrogated by loss-of-function mutation in vab-10, encoding the worm ortholog of mammalian MACF1 6. Like -KB treatment, vab-10 knockdown activates AMP-activated protein kinase (AMPK), and AMPK is required for -KB effects on longevity. The findings suggest a model in which -KB increases longevity by activating AMPK via VAB-10/MACF1 modulation. -KB also delays aging in mammals, increasing the lifespan of aged male mice and the healthspan of both male and female animals. Targeting of broadly expressed scaffolding proteins in connection to cellular energy homeostasis seems to be a clever way that nature has devised for metabolite signals to impinge upon multiple organ and tissue systems, which may have utility for controlling aging and related diseases.

physiology↗

bioRxiv2022

Mechanisms of AGO4 slicing-enhanced RNA-directed DNA methylation

RNA-directed DNA methylation in plants is guided by 24 nt siRNAs generated in parallel with 23 nt RNAs of unknown function. We show that 23 nt RNAs function as passenger strands during 24 nt siRNA incorporation into AGO4. The 23 nt RNAs are then sliced into 11 and 12 nt fragments, with 12 nt fragments remaining associated with AGO4. Slicing recapitulated with recombinant AGO4 and synthetic RNAs reveals that siRNAs of 21-24 nt, with any 5 terminal nucleotide, can guide slicing, with sliced RNAs then retained by AGO4. In vivo, RdDM target locus RNAs that copurify with AGO4 also display a sequence signature of slicing. Comparing plants expressing slicing-competent versus slicing-defective AGO4 shows that slicing elevates cytosine methylation levels at virtually all RdDM loci. We propose that siRNA passenger strand elimination and AGO4 tethering to sliced target RNAs are distinct modes by which AGO4 slicing enhances RNA-directed DNA methylation.

molecular biology↗

bioRxiv2022

Loss of ZNF251 stimulates NHEJ resulting in PARP inhibitor resistance in BRCA1-mutated cancer cells

Poly (ADP-ribose) polymerase inhibitors (PARPis) represent a promising new class of agents that have demonstrated efficacy in treating various cancers, particularly those with BRCA1/2 mutations. Cancer-associated BRCA1/2 mutations disrupt DNA double-strand break (DSB) repair by homologous recombination (HR). PARP inhibitors (PARPis) have been used to trigger synthetic lethality in BRCA1/2-mutated cancer cells by promoting the accumulation of toxic DSBs. Unfortunately, resistance to PARPis is common and can occur through multiple mechanisms, including the restoration of HR and/or stabilization of replication forks. To gain a better understanding of the mechanisms underlying PARPis resistance, we conducted an unbiased CRISPR-pooled genome-wide library screen to identify new genes whose deficiency confers resistance to the PARPi olaparib. Our research revealed that haploinsufficiency of the ZNF251 gene, which encodes zinc finger protein 251, is associated with resistance to PARPis in various breast and ovarian cancer cell lines carrying BRCA1 mutations. Mechanistically, we discovered that ZNF251 haploinsufficiency leads to stimulation of RAD51-mediated HR repair of DSBs in olaparib-treated BRCA1-mutated cancer cells. Moreover, we demonstrated that a RAD51 inhibitor reversed PARPi resistance in ZNF251 haploinsufficient cancer cells harboring BRCA1 mutations. Our findings provide important insights into the mechanisms underlying PARPis resistance by highlighting the role of RAD51 in this phenomenon.

cancer biology↗

bioRxiv2022

Spatially Resolved Single-cell Translatomics at Molecular Resolution

The precise control of mRNA translation is a crucial step in post-transcriptional gene regulation of cellular physiology. However, it remains a major challenge to systematically study mRNA translation at the transcriptomic scale with spatial and single-cell resolutions. Here, we report the development of RIBOmap, a three-dimensional (3D) in situ profiling method to detect mRNA translation for thousands of genes simultaneously in intact cells and tissues. By applying RIBOmap to 981 genes in HeLa cells, we revealed remarkable dependency of translation on cell-cycle stages and subcellular localization. Furthermore, we profiled single-cell translatomes of 5,413 genes in the adult mouse brain tissue with a spatial cell atlas of 62,753 cells. This spatial translatome profiling detected widespread patterns of localized translation in neuronal and glial cells in intact brain tissue networks. Together, RIBOmap presents the first spatially resolved single-cell translatomics technology, accelerating our understanding of protein synthesis in the context of subcellular architecture, cell types, and tissue anatomy.

genomics↗

bioRxiv2022

Spatiotemporally resolved transcriptomics reveals subcellular RNA kinetic landscape

Spatiotemporal regulation of the cellular transcriptome is crucial for proper protein expression and cellular function1. However, the intricate subcellular dynamics of RNA synthesis, decay, export, and translocation remain obscured due to the limitations of existing transcriptomics methods2-8. Here, we report a spatiotemporally resolved RNA mapping method (TEMPOmap) to uncover subcellular RNA profiles across time and space at the single-cell level in heterogeneous cell populations. TEMPOmap integrates pulse-chase metabolic labeling of the transcriptome with highly multiplexed three-dimensional (3D) in situ sequencing to simultaneously profile the age and location of individual RNA molecules. Using TEMPOmap, we constructed the subcellular RNA kinetic landscape of 991 genes in human HeLa cells from upstream transcription to downstream subcellular translocation. Clustering analysis of critical RNA kinetic parameters across single cells revealed kinetic gene clusters whose expression patterns were shaped by multi-step kinetic sculpting. Importantly, these kinetic gene clusters are functionally segregated, suggesting that subcellular RNA kinetics are differentially regulated to serve molecular and cellular functions in cell-cycle dependent manner. Together, these single-cell spatiotemporally resolved transcriptomics measurements provide us the gateway to uncover new gene regulation principles and understand how kinetic strategies enable precise RNA expression in time and space.

genomics↗

bioRxiv2022

VLA-4 suppression by senescence signals regulates meningeal immunity and leptomeningeal metastasis

Leptomeningeal metastasis is associated with dismal prognosis and has few treatment options. However, very little is known about the immune response to leptomeningeal metastasis. Here, by establishing an immunocompetent mouse model of breast cancer leptomeningeal metastasis, we found that tumor-specific CD8+ T cells were generated in deep cervical lymph nodes (dCLNs) and played an important role in controlling leptomeningeal metastasis. Mechanistically, T cells in dCLNs displayed a senescence phenotype and their recruitment was impaired in mice bearing cancer cells that preferentially colonized in leptomeningeal space. Upregulation of p53 suppressed the transcription of VLA-4 in senescent dCLN T cells and consequently inhibited their migration to the leptomeningeal compartment. Clinically, CD8+ T cells from cerebrospinal fluid of patients with leptomeningeal metastasis exhibited senescence and VLA-4 downregulation. Collectively, our findings demonstrated that CD8+ T cell immunosenescence drives leptomeningeal metastasis.

immunology↗

bioRxiv2022

HCR Lateral Flow Assays for Amplified Instrument-Free At-Home SARS-CoV-2 Testing

The lateral flow assay format enables rapid, instrument-free, at-home testing for SARS-CoV-2. Due to the absence of signal amplification, this simplicity comes at a cost in sensitivity. Here, we enhance sensitivity by developing an amplified lateral flow assay that incorporates isothermal, enzyme-free signal amplification based on the mechanism of hybridization chain reaction (HCR). The simplicity of the user experience is maintained using a disposable 3-channel lateral flow device to automatically deliver reagents to the test region in three successive stages without user interaction. To perform a test, the user loads the sample, closes the device, and reads the result by eye after 60 minutes. Detecting gamma-irradiated SARS-CoV-2 virions in a mixture of saliva and extraction buffer, the current amplified HCR lateral flow assay achieves a limit of detection of 200 copies/L using available antibodies to target the SARS-CoV-2 nucleocapsid protein. By comparison, five commercial unamplified lateral flow assays that use proprietary antibodies exhibit limits of detection of 500 copies/L, 1000 copies/L, 2000 copies/L, 2000 copies/L, and 20,000 copies/L. By swapping out antibody probes to target different pathogens, amplified HCR lateral flow assays offer a platform for simple, rapid, and sensitive at-home testing for infectious disease. As an alternative to viral protein detection, we further introduce an HCR lateral flow assay for viral RNA detection. HCR lateral flow assayO_LIAmplified C_LIO_LIInstrument-free C_LIO_LIAt-home C_LIO_LI60 min C_LIO_LINaked eye C_LIO_LISARS-CoV-2 C_LIO_LI200 copies/L C_LI O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=166 SRC="FIGDIR/small/508442v1_ufig1.gif" ALT="Figure 1"> View larger version (23K): org.highwire.dtl.DTLVardef@a04874org.highwire.dtl.DTLVardef@f4ba0borg.highwire.dtl.DTLVardef@e2445corg.highwire.dtl.DTLVardef@f63411_HPS_FORMAT_FIGEXP M_FIG C_FIG

bioengineering↗

bioRxiv2022

Topological Links in Predicted Protein Complex Structures Reveal Limitations of AlphaFold

AlphaFold is making great progress in protein structure prediction, not only for single-chain proteins but also for multi-chain protein complexes. When using AlphaFold-Multimer to predict protein-protein complexes, we observed some unusual structures in which chains are looped around each other to form topologically intertwining links at the interface. To our knowledge, such topological links are never observed in the experimental structures deposited in the Protein Data Bank (PDB). Although it is well known and has been well studied that protein structures may have topologically complex shapes such as knots and links, existing methods are hampered by the chain closure problem and show poor performance in identifying topologically linked structures in protein-protein complexes. Therefore, we address the chain closure problem by using sliding windows from a local perspective and propose an algorithm to measure the topological-geometric features that can be used to identify topologically linked structures. An application of the method to AlphaFold-Multimer-predicted protein complex structures finds that approximately 0.7% of the predicted structures contain topological links. The method presented in this work will facilitate the computational study of protein-protein interactions and help further improve the structural prediction of multi-chain protein complexes.

bioinformatics↗

bioRxiv2022

Environment-wide and epigenome-wide association study of adiposity in "Children of 1997" birth cohort

BackgroundIncreasing childhood adiposity is a global issue requiring potentially local solutions to ensure it does not continue into adulthood. We systematically identified potentially modifiable targets of adiposity at the onset and end of puberty in Hong Kong the most economically developed major Chinese city. MethodsWe conducted an environment-wide association study (EWAS) and an epigenome-wide association study of adiposity to systematically assess associations with body mass index (BMI) and waist-hip ratio (WHR) in Hong Kongs population-representative "Children of 1997" birth cohort. Univariable linear regression was used to select exposures related to adiposity at ~11.5 years (BMI n[≤]7,119, WHR n=5,691) and ~17.6 years (n = 3,618) at Bonferroni-corrected significance, and multivariable linear regression to adjust for potential confounders followed by replication (n=308) and CpG by CpG analysis (n=286) at ~23 years. Findings were compared with evidence from randomized controlled trials (RCTs) and Mendelian randomization (MR) studies. ResultsAt ~11.5 and ~17.6 years the EWAS identified 14 and 37 exposures associated with BMI, as well as seven and 12 associated with WHR respectively. Most exposures had directionally consistent associations at ~23 years. Maternal second-hand smoking, maternal weight, and birth weight were consistently associated with adiposity. Diet (including dairy intake and artificially sweetened beverages), physical activity, snoring, binge eating, and earlier puberty were positively associated with BMI at ~17.6 years, while eating before sleep was inversely associated with BMI at ~17.6 years. Findings for birth weight, dairy intake, binge eating, and possibly earlier puberty are consistent with available evidence from RCTs or MR studies We found 21 CpGs related to BMI and 18 to WHR. ConclusionsThese novel insights into potentially modifiable factors associated with adiposity at the outset and the end of puberty could, if causal, inform future interventions to improve population health in Hong Kong and similar Chinese settings. FundingThis study was supported by the Health and Medical Research Fund Research Fellowship, Food and Health Bureau, Hong Kong SAR Government (#04180097). The DNA extraction was supported by CFS-HKU1.

genetics↗

bioRxiv2022

Tracking neural correlates of prioritizing working memory representations through retrospective attentional strengthening

Previous work has proposed two potentials benefits of retrospective attention on working memory (WM): target strengthening and non-target inhibition. It remains unknown which hypothesis contributes to the improved WM performance, yet the neural mechanisms responsible for this attentional benefit are unclear. Here, we recorded electroencephalography (EEG) signals while 33 participants performed a retrospective-cue WM task. Multivariate pattern classification analysis revealed that only representations of target features were enhanced by valid retrospective attention during the retention, supporting the target strengthening hypothesis. Further univariate analysis found that mid-frontal theta inter-trial phase coherence (ITPC) and ERP components were modulated by valid retrospective attention and correlated with individual differences and moment-to-moment fluctuations on behavioral outcomes, suggesting that both trait- and state-level variability in attentional preparatory processes influence goal-directed behavior. Furthermore, task-irrelevant target spatial location could be decoded from EEG signals, indicating that enhanced spatial binding of target representation promotes high WM precision. Importantly, frontoparietal theta-alpha phase-amplitude-coupling was increased by valid retrospective attention and predicted the reduced randomly guessing rates. This long-range connection supported top-down information flow in engagement of frontoparietal networks, which might organize attentional states to integrate target features. Altogether, these results provide neurophysiological bases that retrospective attention improves WM precision through enhancing representation of target and emphasize the critical role of frontoparietal attentional network in the control of WM representations.

neuroscience↗

bioRxiv2022

CausalCell: applying causal discovery to single-cell analyses

Correlation between objects does not answer many scientific questions because of the lack of causal but the excess of spurious information and is prone to happen by coincidence. Causal discovery infers causal relationships from data upon conditional independence test between objects without prior assumptions (e.g., variables have linear relationships and data follow the Gaussian distribution). Causal interactions within and between cells provide valuable information for investigating gene regulation, identifying diagnostic and therapeutic targets, and designing experimental and clinical studies. The rapid increase of single-cell data permits inferring causal interactions in many cell types. However, because no algorithms have been designed for handling abundant variables and few algorithms have been evaluated using real data, how to apply causal discovery to single-cell data remains a challenge. We report a pipeline and web server (http://www.gaemons.net/causalcell/causalDiscovery/) for accurately and conveniently performing causal discovery. The pipeline has been developed upon the benchmarking of 18 algorithms and the analyses of multiple datasets. Our applications indicate that only complicated algorithms can generate satisfactorily reliable results. Critical issues are discussed, and tips for best practices are provided.

bioinformatics↗

bioRxiv2022

Evolution of insecticide resistance via parallel amino acid substitutions in insect pests and their parasitoid wasps

Insecticides have become the primary selective force in many insect species; however, whether beneficial insects developed resistance remains unknown. We analyzed the sequences of hymenopteran GABAA receptor subunit gene Rdl (resistance to dieldrin), which encodes the target of cyclodiene and phenylpyrazole insecticides. The resistance-conferring A2 S mutations were found in seven parasitoid wasps and similar amino acid replacements at homologous sites have been identified in four of their resistant hosts. Our findings indicate how parallel molecular evolution at a single amino acid site confers adaptation in both insects and their natural enemies, which may shape species interactions and community structure.

ecology↗

bioRxiv2022

RBP45d is required for 5' splice site selection via binding to intronic U-rich elements and interaction with PRP39a in Arabidopsis thaliana

A large number of cryptic splice sites in eukaryotic genome are generally dormant unless activated by mutations of authentic splice sites or splicing factors. How cryptic splice sites are used remains unknown in plants. Here, we identified two cryptic splicing regulators, RBP45d and PRP39a that are homologs of yeast U1 auxiliary protein Nam8 and Prp39, respectively, via genetic screening for suppressors of the virescent sot5 mutant, which results from a point mutation at the 5 splice site (5 ss) of intron 7. PCR and DNA sequencing data showed that loss-of-function mutations in RBP45d and PRP39a significantly increase the level of a cryptically spliced mRNA that encodes a mutated but partially functional sot5 protein, rescuing sot5 to the WT phenotype. Yeast two hybrid and bimolecular fluorescence complementation assays demonstrated that RBP45d and PRP39a interact each other and also with the U1C, a core subunit of U1 small nuclear ribonucleoprotein (U1 snRNP). RNA electronic mobility shift assay showed that RBP45d directly binds to the uridine (U)-rich RNA sequence downstream of the cryptic 5 ss. Consistently, our transcriptomic analysis revealed that a set of introns with U-rich sequences are retained in rbp45d. However, we found that other RBP45/47 members do not function redundantly with RBP45d, at least in regulation of cryptic splicing. Collectively, our data suggest that RBP45d is required for 5 ss selection via binding to intronic U-rich elements and PRP39a in plants. One sentence summaryThe Arabidopsis RBP45d interacting with U1C and PRP39a is required for 5 ss selection via binding to intronic U-rich elements.

plant biology↗

bioRxiv2022

Development of highly potent non-covalent inhibitors of SARS-CoV-2 3CLpro

The SARS-CoV-2 virus is the causal agent of the ongoing pandemic of coronavirus disease 2019 (COVID-19). There is an urgent need for potent, specific antiviral compounds against SARS-CoV-2. The 3C-like protease (3CLpro) is an essential enzyme for the replication of SARS-CoV-2 and other coronaviruses, and thus is a target for coronavirus drug discovery. Nearly all inhibitors of coronavirus 3CLpro reported so far are covalent inhibitors. Here, we report the development of specific, non-covalent inhibitors of 3CLpro. The most potent one, WU-04, effectively blocks SARS-CoV-2 replications in human cells with EC50 values in the 10-nM range. WU-04 also inhibits the 3CLpro of SARS-CoV and MERS-CoV with high potency, indicating that it is a pan-inhibitor of coronavirus 3CLpro. WU-04 showed anti-SARS-CoV-2 activity similar to that of PF-07321332 (Nirmatrelvir) in K18-hACE2 mice when the same dose was administered orally. Thus, WU-04 is a promising drug candidate for coronavirus treatment. One-Sentence SummaryA oral non-covalent inhibitor of 3C-like protease effectively inhibits SARS-CoV-2 replication.

microbiology↗

bioRxiv2022

Complex rules of vocal sequencing in marmoset monkeys

Marmoset monkeys have attracted much attention as a non-human primate model for studying vocal communication, but the call pattern and its meaning in marmoset communication are largely unknown. Here, we analyze sounds produced by hundreds of marmosets either in isolation or in pairs and reveal distinct call patterns in marmoset communication. The most prominent phee calls could be categorized into multiple grades based on the number of comprising phee syllables. Call transitions exhibited non-random patterns, favoring transition to the same or adjacent grade, with long sequences limited within two adjacent grades. The interval, composition, and temporal distribution of calls were significantly different between isolated and paired marmosets. Notably, different patterns of phee calls correlated with the heart rates and emotional states of marmoset, with the higher call grade reflecting a more agitated state. Antiphonal calling also exhibited distinct patterns and phee calls directly affected the heart rate of the listener in a manner depending on the grade of phee calls. Thus, phee call patterns in marmosets could encode emotional states and transmit emotion between turn-taking marmosets. How emotional expression in animals evolves into semantic communication in humans remains a mystery. Such complex call patterns in marmoset vocalization could represent the evolutionary prelude to semantic communication in primates.

animal behavior and cognition↗

bioRxiv2022

A molecular mechanism for membrane chaperoning by a late embryogenesis abundant protein

Environmental stress can result in substantial damage to proteins, membranes, and genetic material, impacting organismal survival1-3. Stress tolerance can be conferred by intrinsically disordered proteins (IDPs)4 that lack stable tertiary structure. IDPs from the large family of late embryogenesis abundant (LEA) proteins confer a fitness advantage when heterologously expressed5,6. Such protection suggests a general molecular function leading to stress tolerance, although the mechanisms remain unclear. Here, we report that a tardigrade LEA protein that confers stress tolerance in yeast acts as a molecular chaperone for the mitochondrial membrane. This protein, named HeLEA1, localizes to the mitochondrial matrix, and harbors conserved LEA sequence motifs that undergo dynamic disorder-to-helical transition upon binding to negatively charged membranes. Yeast expressing HeLEA1 show increased mitochondrial membrane fluidity, increased membrane potential, and enhanced tolerance to hyperosmotic stress under non-fermentative growth without significantly altering mitochondrial lipid composition or triggering a generic stress response. We demonstrate that membrane binding ameliorates excess surface tension, possibly by stabilizing lipid packing defects. Evolutionary analysis suggests that HeLEA1 homologs localize to different membrane-bound organelles and share similar sequence and biophysical features. We suggest that membrane chaperoning by LEA proteins represents a general biophysical solution that can operate across the domains of life.

biophysics↗

bioRxiv2022

Nardilysin-Regulated Scission Mechanism Activates Polo-like Kinase 3 to Suppress the Development of Pancreatic Cancer

Pancreatic ductal adenocarcinoma (PDAC) develops through step-wise genetic and molecular alterations including Kras mutation and inactivation of apoptotic pathways. Here, we find that development of anoikis resistance and metastasis of KrasG12D-driven PDAC in mice is accelerated by deleting Plk3, explaining the often reduced Plk3 expression in human PDAC. Importantly, a 41 kDa Plk3 (p41Plk3) that contained the entire kinase domain at the N-terminus (1-353 aa) is activated by scission of the precursor p72Plk3 at Arg354 by metalloendopeptidase Nardilysin (NRDC), and the resulting p32Plk3 C-terminal Polo-box domain (PBD) was quickly removed by proteasome degradation preventing the p41Plk3 inhibition by PBD. We found that p41Plk3 is the activated form of Plk3 that regulates a feedforward mechanism to promote anoikis and suppress PDAC and metastasis. p41Plk3 phosphorylates c-Fos on Thr164, which in turn, induces expression of Plk3 and pro-apoptotic genes. These findings uncovered an NRDC-regulated post-translational mechanism (PTM) that activates Plk3, establishing a prototypic regulation by scission mechanism.

cancer biology↗