Biology subjects

Zhang, L.

Publications and source records attributed to Zhang, L..

At least 991 records · Page 55Linked to original sources

bioRxiv2022

Genomic heterogeneity in pancreatic cancer organoids and its stability with culture

The establishment of patient-derived pancreatic cancer organoid culture in recent years creates an exciting opportunity for researchers to perform a wide range of in vitro studies on a model that closely recapitulates the tumor. Among the outstanding questions in pancreatic cancer biology are the causes and consequences of genomic heterogeneity observed in the disease. However, to use pancreatic cancer organoids as a model to study genomic variations, we need to first understand the degree of genomic heterogeneity and its stability within organoids. Here, we used single-cell whole-genome sequencing to investigate the genomic heterogeneity of two independent pancreatic cancer organoids, as well as their genomic stability with extended culture. Clonal populations with similar copy number profiles were observed within the organoids, and the proportion of these clones was shifted with extended culture, suggesting the growth advantage of some clones. However, sub-clonal genomic heterogeneity was also observed within each clonal population, indicating the genomic instability of the pancreatic cancer cells themselves. Furthermore, our transcriptomic analysis also revealed a positive correlation between copy number alterations and gene expression regulation, suggesting the functionality of these copy number alterations.

cancer biology↗

bioRxiv2022

A Long-Circulating Vector for Aptamers Based upon Polyphosphodiester-Backboned Molecular Brushes

Aptamers face challenges for use outside the ideal conditions in which they are developed. These difficulties are most palpable in vivo due to nuclease activities, rapid clearance, and off-target binding. Herein, we demonstrate that a polyphosphodiester-backboned molecular brush can suppress enzymatic digestion, reduce non-specific cell uptake, enable long blood circulation, and rescue the bioactivity of a conjugated aptamer in vivo. The backbone along with the aptamer is assembled via solid-phase synthesis, followed by installation of poly(ethylene glycol) (PEG) side chains using a two-step process with near-quantitative efficiency. The synthesis allows for precise control over polymer size and architecture. Consisting entirely of building blocks that are generally recognized as safe for therapeutics, this novel molecular brush is expected to provide a highly translatable route for aptamer-based therapeutics.

pharmacology and toxicology↗

bioRxiv2022

SiPLATZ12 transcript factor regulates multiple yield traits and salt tolerance in foxtail millet (Setaria italica)

Grain yield and salt tolerance are critical for crop production. However, the genetic and biochemical basis underlying the trade-off of these characters remain poorly described in crops. We show here that SiPLATZ12 transcription factor positively regulates multiple elite yield traits at the expense of salt tolerance in foxtail millet. SiPLATZ12 overexpression increases seed size, panicle length, and stem diameter, while reduces plant height and salt tolerance of foxtail millet. A 9-bp insertion in the SiPLATZ12 promoter has significant effects on the different expression of SiPLATZ12, multiple yield traits, and salt tolerance between foxtail millet and its wild ancestor, green foxtail. Moreover, SiPLATZ12 upregulates the expression of genes involved in seed development, but repressing the transcription of most NHX, SOS, and CBL genes to regulate Na+, K+ and pH homeostasis. Therefore, our results uncover a domesticated site that could be used to improve grain yield and salt tolerance in foxtail millet.

molecular biology↗

bioRxiv2022

Underlying beneficial effects of Rhubarb on constipation-induced inflammation, disorder of gut microbiome and metabolism

BackgroundAlthough constipation is a common syndrome and a worldwide health problem. Constipation patients are becoming younger with a 29.6% overall prevalence in the children, which has captured great attention because of its epigenetic rejuvenation and recurrent episodes. Despite the usage of rhubarb to relieve constipation, novel targets and genes involved in target-relevant pathways with remarkable functionalities should still be sought after. Materials and methodsWe established a reliable constipation model in C57B/6N male mice using intragastric administration diphenoxylate and the eligible subjects received 600mg/25g rhubarb extraction to ameliorate constipation. Resultant constipation was morphological and genetically compared with the specimen from different groups. ResultsThe constipation mice exhibited thicker muscle layers, improved content of cytokines, including IL-17 and IL-23, and lower content of IL-22. The bacterial abundance and diversity varied tremendously. Notably, the alterations were reversed after rhubarb treatment. Additionally, SCFA and MLCFA were significantly influenced by constipation accompanied by enhanced expressions of SCFA receptors, GPR41 and GPR43. ConclusionThis thesis has provided an insight that rhubarb promoted the flexibility of collagen fiber, reduced pro-inflammatory cytokines and enhanced anti-inflammatory cytokines, and maintained intestinal microflora balance with potential effects on affecting the metabolism of fatty acids and polyamines.

pharmacology and toxicology↗

bioRxiv2022

TANGO2 deficient iPSC-differentiated cardiomyocyte and dermal fibroblasts have normal mitochondrial OXPHOS function

Bi-allelic loss-of-function mutations in TANGO2 (Transport and Golgi Organization protein 2) cause a rare multiorgan genetic disorder. Despite normal cardiac function at baseline, patients may experience lethal cardiac arrhythmias during "crises" often associated with metabolic stresses such as fasting, viral illness and fever. The molecular function of TANGO2 remains largely unknown. Previous studies have suggested a functional association with the mitochondrion, however definitive evidence is lacking. Further, functional impact of TANGO2 deficiency on mitochondrial function has not been investigated in a cardiac model. In this study, we utilized a recently developed patient-derived induced pluripotent stem cell differentiated cardiomyocytes (iPSC-CM) model by our group, along with patient-derived dermal fibroblast model, to interrogate whether loss of TANGO2 function leads to defective mitochondrial function. Both baseline and fasting condition were investigated. Oxygen consumption rate (OCR) was measured in Seahorse assays to assess mitochondrial function in vitro. The results showed both TANGO2 deficient dermal fibroblasts and iPSC-CM had no apparent defects in mitochondrial oxidative phosphorylation (OXPHOS) function under either baseline or fasting condition. Based on our study, we conclude that the lethal cardiac arrhythmias in TANGO2 patients are unlikely to be related to impaired mitochondrial OXPHOS function in the cardiomyocytes.

cell biology↗

bioRxiv2022

Ralstonia solanacearum alters root developmental programs in auxin-dependent and independent manners

Microbial pathogens and other parasites can modify the development of their hosts, either as a target or a side effect of their virulence activities. The plant pathogenic bacterium Ralstonia solanacearum, causal agent of the devastating bacterial wilt disease, is a soil-borne microbe that invades host plants through their roots, and later proliferates in xylem vessels. In this work, we studied the early stages of R. solanacearum infection in the model plant Arabidopsis thaliana, using an in vitro infection system. In addition to the previously reported inhibition of primary root length and increase in root hair formation at the root tip, we observed an earlier xylem differentiation during R. solanacearum infection that occurs in a HrpG-dependent manner, suggesting that the pathogen actively promotes the development of the vascular system upon invasion of the root. Moreover, we found that the phytohormone auxin, of which the accumulation is promoted by the bacterial infection, is required for the R. solanacearum-triggered induction of root hair formation, but not earlier xylem differentiation. Altogether, our results shed light on the capacity of R. solanacearum to induce alterations of root developmental pathways and on the role of auxin in this process.

plant biology↗

bioRxiv2022

Structure of the GOLD-domain seven-transmembrane helix protein family member TMEM87A

TMEM87s are eukaryotic transmembrane proteins with two members (TMEM87A and TMEM87B) in humans. TMEM87s have proposed roles in protein transport to and from the Golgi, as mechanosensitive ion channels, and in developmental signaling. TMEM87 disruption has been implicated in cancers and developmental disorders. To better understand TMEM87 structure and function, we determined a cryo-EM structure of human TMEM87A in lipid nanodiscs. TMEM87A consists of a Golgi-dynamics (GOLD) domain atop a membrane spanning seven-transmembrane helix domain with a large cavity open to solution and the membrane outer leaflet. Structural and functional analyses suggest TMEM87A may not function as an ion channel or G-protein coupled receptor. We find TMEM87A shares its characteristic domain arrangement with seven other proteins in humans; three that had been identified as evolutionary related (TMEM87B, GPR107, and GPR108) and four previously unrecognized homologs (GPR180, TMEM145, TMEM181, and WLS)). Among these structurally related GOLD domain seven-transmembrane helix (GOST) proteins, WLS is best characterized as a membrane trafficking and secretion chaperone for lipidated Wnt signaling proteins. We find key structural determinants for WLS function are conserved in TMEM87A. We propose TMEM87A and structurally homologous GOST proteins could serve a common role in trafficking membrane-associated cargo.

biophysics↗

bioRxiv2022

A Mechanistic Study on the Cellular Uptake, Intracellular Trafficking, and Antisense Gene Regulation of Bottlebrush Polymer-Conjugated Oligonucleotides

We have developed a non-cationic transfection vector in the form of a bottlebrush polymer-antisense oligonucleotide (ASO) conjugate. Termed pacDNA (polymer-assisted compaction of DNA), these agents show improved biopharmaceutical characteristics and antisense potency in vivo while suppressing non-antisense side effects. Nonetheless, there still lacks a mechanistic understanding regarding the cellular uptake, subcellular trafficking, and gene knockdown with pacDNA. Here, we show that the pacDNA enters human non-small cell lung cancer cells (NCI-H358) predominantly by scavenger receptor-mediated endocytosis and macropinocytosis, and trafficks via the endolysosomal pathway within the cell. The pacDNA significantly reduces a target gene expression (KRAS) in the protein level but not in the mRNA level, despite that the transfection of free ASOs causes ribonuclease H1 (RNase H)-dependent degradation of KRAS mRNA. In addition, the antisense activity of pacDNA is independent of ASO chemical modification, suggesting that the pacDNA functions as a steric blocker. TOC O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=148 SRC="FIGDIR/small/496353v1_ufig1.gif" ALT="Figure 1"> View larger version (34K): org.highwire.dtl.DTLVardef@56e08eorg.highwire.dtl.DTLVardef@1b09510org.highwire.dtl.DTLVardef@a785corg.highwire.dtl.DTLVardef@1641874_HPS_FORMAT_FIGEXP M_FIG C_FIG

bioengineering↗

bioRxiv2022

A causal role of the human left temporoparietal junction in computing social influence during goal-directed learning

The human temporoparietal junction (TPJ) is a brain area crucial for processing social information. Although brain stimulation studies have started to explore the causal function of TPJ under social contexts, few have explicitly considered bilateral TPJ as target regions. Here, leveraging non-invasive continuous theta-burst stimulation (cTBS) and hierarchical Bayesian computational modeling, we tested whether left or right TPJ (with vertex as control) is causally involved in how dissenting choices by others influence individuals choice adjustments in goal-directed learning. In our social learning paradigm, participants (N = 31) first made their private decision, and then were allowed to re-adjust their choices after observing choices of four other players. Behaviorally, we show that disruption of the left, but not the right TPJ, weakened participants choice adjustment and delayed their response speed when confronted with dissenting information from the other players. Computationally, disrupting activity in the left TPJ attenuated the degree of computing social influence during choice adjustment, whereas the extent to which how observational learning from others choices was integrated into direct learning remained intact. Together, our results provide evidence for the causal role of left TPJ in social influence during goal-directed learning and shed light on the relational function (with respect to oneself) of the TPJ in social cognition.

neuroscience↗

bioRxiv2022

Hydrological dynamics drive the transition of antibiotic resistance genes between particle-attached and free-living lifestyles in a deep freshwater reservoir

Despite the growing awareness of antibiotic resistance genes (ARGs) spreading in the environment, there is a knowledge gap on the fate and transport of ARGs in particle-attached (PA) and free-living (FL) lifestyles in deep freshwater ecosystems experiencing seasonal hydrological changes. Here, we examined the ARG profiles using high-throughput quantitative PCR in PA and FL lifestyles at four seasons representing two hydrological seasons (i.e., vertical mixing and thermal stratification) in the Shuikou Reservoir (SR), Southern China. The results indicated that seasonal hydrological dynamics were critical for influencing ARGs in PA and FL fractions, and the transition of ARGs between the two lifestyles. Although both PA and FL ARG profiles were likely to be shaped by horizontal gene transfer, PA and FL ARGs had different responses to the changes in physico-chemicals (e.g., nutrients and dissolved oxygen) caused by seasonal hydrological dynamics. The particle-associated niche (PAN) index revealed that there were 94 non-conservative ARGs (i.e., no preferences for PA and FL), 23 conservative ARGs that preferred PA lifestyle, and 16 conservative ARGs for FL lifestyle. A sharp decline in the number of conservative ARGs in stratified seasons suggests a hydrological dynamics-dependent transition of ARGs between two lifestyles. Remarkably, the conservative ARGs (in PA or FL lifestyle) were more closely related to bacterial OTUs in their preferred lifestyle compared to their counterpart lifestyle, suggesting a lifestyle-dependent ARG enrichment. Altogether, these findings enhance our understanding of the role of seasonal hydrological changes in the dissemination of ARGs in different size fractions in deep aquatic ecosystems.

ecology↗

bioRxiv2022

Trans-Driver: a deep learning approach for cancer driver gene discovery with multi-omics data

Driver genes play a crucial role in the growth of cancer cells. Accurate identification of cancer driver genes is helping to strengthen the understanding of cancer pathogenesis and is conducive to the development of cancer treatment and drug-targe driver genes. However, due to the diversity and complexity of the multi-omics data, it is still challenging to identify cancer drivers.In this study, we propose Trans-Driver, a deep supervised learning method with a novel transformer network, which integrates multi-omics data to learn the differences and associations between different omics data for cancer drivers discovery. Compared with other state-of-the-art driver gene identification methods, Trans-Driver has achieved excellent performance on TCGA and CGC data Machine learning for multi-omics data integration in cancer. Among 20,000 protein-coding genes, Trans-Driver reported 185 candidate driver genes, of which 103 genes (about 55%) were included in the gold standard CGC data set. Finally, we analyzed the contribution of each feature to the identification of driver genes. We found that the integration of multi-omics data can improve the performance of our method compared with using only somatic mutation data. Through detailed analysis, we found that the candidate drivers are clinically meaningful, proving the practicability of Trans-Driver. Author summaryMany methods have been developed to identify cancer driver genes. However, most of these methods use single-omics data for cancer driver gene identification. Multi-omics-based methods for cancer driver gene identification are rare. Trans-Driver uses deep learning to process multi-omics data and learn the relationships between multi-omics data for cancer driver gene prediction. We have predicted 185 candidate cancer driver genes out of among 20,000 protein-coding genes. Also, we performed cancer driver gene prediction on 33 cancer types, and we identified the cancer driver genes corresponding to each cancer type. And, we observed that the predicted cancer driver genes were shown to have a role in cancer progression in recent studies. Our proposed method for cancer driver gene identification using multi-omics data has improved performance compared to using mutation data alone.

bioinformatics↗

bioRxiv2022

Identification of a small chemical as a lysosomal calcium mobilizer and characterization of its ability to inhibit autophagy and viral infection

We previously identified GADPH as one of the cyclic adenosine diphosphoribose (cADPR)s binding proteins and found that GADPH participates in cADPR-mediated Ca2+ release from ER via RyRs. Based on the simulated cADPR-GAPDH complex structure, we performed the structure-based drug screening, identified several small chemicals with high docking scores to cADPRs binding pocket in GAPDH, and showed that two of these compounds, C244 and C346, are potential cADPR antagonists. We further synthesized several analogs of C346, and found that its analog, G42, also mobilized Ca2+ release from lysosomes. G42 alkalized lysosomal pH, and inhibited autophagosome-lysosome fusion. Moreover, G42 markedly inhibited Zika virus (ZIKV, a flavivirus) or murine hepatitis virus (MHV, a {beta}-coronavirus) infections of host cells. These results suggest that G42 inhibits virus infection, likely by triggering lysosomal Ca2+ mobilization and inhibiting autophagy.

microbiology↗

bioRxiv2022

Strengthening of enterococcal biofilms by Esp

Multidrug-resistant (MDR) Enterococcus faecalis are major causes of hospital-acquired infections. Numerous clinical strains harbor a large pathogenicity island that encodes enterococcal surface protein (Esp), which is suggested to promote biofilm production and virulence, but this remains controversial. To resolve this issue, we characterized the Esp N-terminal region, the portion implicated in biofilm production. Small angle X-ray scattering indicated that the N-terminal region had a globular head, which consisted of two DEv-Ig domains as visualized by X-ray crystallography, followed by an extended tail. The N-terminal region was not required for biofilm production but instead significantly strengthened biofilms against mechanical or degradative disruption, greatly increasing retention of Enterococcus within biofilms. Biofilm strengthening required low pH, which resulted in Esp unfolding, aggregating, and forming amyloid-like structures. The pH threshold for biofilm strengthening depended on protein stability. A truncated fragment of the first DEv-Ig domain, plausibly generated by a host protease, was the least stable and sufficient to strengthen biofilms at pH [≤] 5.0, while the entire N-terminal region and intact Esp on the enterococcal surface was more stable and required a pH [≤] 4.3. These results suggested a virulence role of Esp in strengthening enterococcal biofilms in acidic abiotic or host environments.

microbiology↗

bioRxiv2022

An intelligent synthetic bacterium with sound-integrated ability for chronological toxicant detection, degradation, and lethality

Modules, toolboxes, and systems of synthetic biology are being designed to solve environmental problems. However, weak and decentralized functional modules require complicated controls. To address this issue, we investigated an integrated system that can complete detection, degradation, and lethality, in chronological order without exogenous inducers. Biosensors were optimized by regulating expression of receptor and reporter to get higher sensitivity and output signal. Several stationary-phase promoters were selected and compared, while promoter Pfic was chosen to express the degradation enzyme. We created two concepts of lethal circuits by testing various toxic proteins, with a toxin/antitoxin circuit showing a potent lethal effect. Three modules were coupled, step-by-step. Detection, degradation, and lethality were sequentially completed, and the modules had partial attenuation compared to pre-integration, except for degradation. Our study provides a novel concept for integrating and controlling functional modules, which can accelerate the transition of synthetic biology from a concept to practical applications. TeaserWe provide new ideas for integration and chronological control of multiple modules in synthetic biology.

synthetic biology↗

bioRxiv2022

NcPath: A novel tool for visualization and enrichment analysis of human non-coding RNA and KEGG signaling pathways

Noncoding RNAs play important roles in transcriptional processes and participate in the regulation of various biological functions, in particular miRNAs and lncRNAs. Despite their importance for several biological functions, the existing signaling pathway databases do not include information on miRNA and lncRNA. Here, we redesigned a novel pathway database named NcPath by integrating and visualizing a total of 178,308 human experimentally-validated miRNA-target interactions (MTIs), 36,537 experimentally-verified lncRNA target interactions (LTIs), and 4,879 experimentally-validated human ceRNA networks across 222 KEGG pathways (including 27 sub-categories). To expand the application potential of the redesigned NcPath database, we identified 553,523 reliable lncRNA-PCG interaction pairs by integrating co-expression relations, ceRNA relations, co-TF-binding interactions, co-Histone-modification interactions, cis-regulation relations and lncPro Tool predictions between lncRNAs and protein-coding genes. In addition, to determine the pathways in which miRNA/lncRNA targets are involved, we performed a KEGG enrichment analysis using an hypergeometric test. The NcPath database also provides information on MTIs/LTIs/ceRNA networks, PubMed IDs, gene annotations and the experimental verification method used. In summary, the NcPath database will serve as an important and continually updated platform that provides annotation and visualization of the pathways on which noncoding RNAs (miRNA and lncRNA) are involved, and provide support to multimodal noncoding RNAs enrichment analysis. The NcPath database is freely accessible at http://ncpath.pianlab.cn/.

bioinformatics↗

bioRxiv2022

Spatiotemporal dynamics of zygotic genome activation in basal chordates revealed by interspecific hybrids

Zygotic genome activation (ZGA), a universal process in early embryogenesis that occurs during the maternal-to-zygotic transition, involves reprogramming in the zygotic nucleus that initiates global transcription. In recent decades, knowledge of this process has been acquired from research on various model organisms; however, a consensus explanation of the mechanism underlying the process, especially in relation to housekeeping gene reactivation, is lacking. Here, we used hybrids derived from two ascidian species (Ciona robusta and C. savignyi), which diverged >120 Mya with significant divergence among most orthologous genes, to symmetrically document the unique dynamics of ZGA in urochordates. We found two co-ordinated waves of ZGA, representing early developmental and housekeeping gene reactivation, during the 8-cell to 110-cell stage. Comparative analysis revealed the regulatory connection between maternal and zygotic genes as well as allelic-specific expression in a species-rather than parental-related manner, which was attributed to the divergence of cis-regulatory elements. Single-cell RNA sequencing revealed that spatial differential reactivation of paternal housekeeping genes was significantly correlated with the mechanical property of each cell type. These findings potentially provide a new system for understanding the evolution and adaptation of strategies regulating ZGA in basal chordates.

developmental biology↗

bioRxiv2022

MEBOCOST: Metabolic Cell-Cell Communication Modeling by Single Cell Transcriptome

We developed MEBOCOST, a computational algorithm for quantitatively inferring metabolite-mediated intercellular communications using single cell RNA-seq data. The algorithm identifies cell-cell communications in which metabolites, such as lipids, are secreted by sender cells and traveled to interact with sensor proteins of receiver cells. The sensor proteins on receiver cell might be cell surface receptors, transporters across the cell membrane, or nuclear receptors. MEBOCOST relies on a comprehensive database of metabolite-sensor partners, which we manually curated from the literatures and other public sources. MEBOCOST defines sender and receiver cells for an extracellular metabolite based on the expression levels of the enzymes and sensors, respectively, thus identifies metabolite-sensor communications between the cells. Applying MEBOCOST to mouse brown adipose tissue (BAT) successfully recaptured known metabolite-mediated cell communications and further identified new communications. Additionally, MEBOCOST identified a set of BAT intercellular metabolite-sensor communications that was regulated by cold exposure of the mice. MEBOCOST will be useful to numerous researchers to investigate metabolite-mediated cell-cell communications in many biological and disease models. The MEBOCOST software is freely available at https://github.com/zhengrongbin/MEBOCOST.

bioinformatics↗

bioRxiv2022

Chemical genetic screening identifies nalacin as an inhibitor of GH3 amido synthetase for auxin conjugation

Root system is critical for plant growth and development. To develop plant growth regulators functioning in root development, we performed a phenotype-based chemical screen in Arabidopsis and identified a chemical, nalacin, that mimicked the effects of auxin on root development. Genetic, pharmacological and biochemical approaches demonstrated that nalacin exerts its auxin-like activities by inhibiting indole-3-acetic acid (IAA) conjugation that is mediated by Gretchen Hagen 3 (GH3) acyl acid amido synthetases. The crystal structure of Arabidopsis GH3.6 in complex with D4 (a derivative of nalacin) together with docking simulation analysis revealed the molecular basis of the inhibition of group II GH3 by nalacin. Sequence alignment analysis indicated broad bioactivities of nalacin and D4 as inhibitors of GH3s in vascular plants, which were confirmed, at least, in tomato and rice. In summary, our work identifies nalacin as a potent inhibitor of IAA conjugation mediated by group II GH3 that plays versatile roles in hormone-regulated plant development and has potential applications in both basic research and agriculture.

plant biology↗