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Yang, R.

Publications and source records attributed to Yang, R..

At least 199 records · Page 11Linked to original sources

Right lateralized posterior parietal theta-gamma coupling during sustained attention in mice

Sustained attention is supported by circuits in the frontoparietal attention network. In human and primate studies, the right posterior parietal cortex (PPC) shows dominance for sustained attention, and phase-amplitude coupling (PAC) throughout the frontoparietal network correlates with performance on attention tasks. Here we evaluate oscillatory dynamics of bilateral PPC in mice during the 5-Choice Serial Reaction Time Task (5-CSRTT). Right PPC theta-gamma PAC (TG-PAC) and gamma power were independently elevated to a greater degree than the left PPC during the period prior to a correct response and were significantly correlated with accuracy in both simple and difficult tasks. Greater task difficulty was also associated with greater hemispheric asymmetry in TG-PAC, favoring the right PPC. These findings highlight the engagement of PPC with sustained attention in mice, reflected by increases in TG-PAC and gamma power, with maximal expression in the right hemisphere.

neuroscience↗

Essential amnion signals for primate primitive streak formation resolved by scRNA map

Essential genes for murine embryonic development can demonstrate a disparate phenotype in human cohorts. By generating a transcriptional atlas containing >30,000 cells from postimplantation non-human primate embryos, we discovered that ISL1, a gene with a well-established role in cardiogenesis, controls a gene regulatory network in primate amnion. CRISPR/Cas9-targeting of ISL1 resulted in non-human primate embryos which did not yield viable offspring, demonstrating that ISL1 is critically required in primate embryogenesis. On a cellular level, mutant ISL1 embryos displayed a failure in mesoderm formation due to reduced BMP4 signaling from the amnion. Via loss of function and rescue studies in human embryonic stem cells we confirmed a similar role of ISL1 in human in vitro derived amnion. This study highlights the importance of the amnion as a signaling center during primate mesoderm formation and demonstrates the potential of in vitro primate model systems to dissect the genetics of early human embryonic development.

developmental biology↗

Computational Study of Ions and Water Permeation and Transportation Mechanisms of the SARS-CoV-2 Pentameric E Protein Channel

Coronavirus disease 2019 (COVID-19) is caused by a novel coronavirus (SARS-CoV-2) and represents the causative agent of a potentially fatal disease that is of public health emergency of international concern. Coronaviruses, including SARS-CoV-2, encode an envelope (E) protein, which is a small, hydrophobic membrane protein; the E protein of SARS-CoV-2 has high homology with that of severe acute respiratory syndrome coronavirus. (SARS-CoV) In this study, we provide insights into the function of the SARS-CoV-2 E protein channel and the ion and water permeation mechanisms on the basis of combined in silico methods. Our results suggest that the pentameric E protein promotes the penetration of monovalent ions through the channel. Analysis of the potential mean force (PMF), pore radius and diffusion coefficient reveals that Leu10 and Phe19 are the hydrophobic gates of the channel. In addition, the pore demonstrated a clear wetting/dewetting transition with monovalent cation selectivity under transmembrane voltage, which indicates that it is a hydrophobic voltage-dependent channel. Overall, these results provide structural-basis insights and molecular-dynamic information that are needed to understand the regulatory mechanisms of ion permeability in the pentameric SARS-CoV-2 E protein channel.

biophysics↗

Comparative transcriptome analysis reveals the intensive early-stage responses of host cells to SARS-CoV-2 infection

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has caused a widespread outbreak of highly pathogenic COVID-19. It is therefore important and timely to characterize interactions between the virus and host cell at the molecular level to understand its disease pathogenesis. To gain insights, we performed high-throughput sequencing that generated time-series data simultaneously for bioinformatics analysis of virus genomes and host transcriptomes implicated in SARS-CoV-2 infection. Our analysis results showed that the rapid growth of the virus was accompanied by an early intensive response of host genes. We also systematically compared the molecular footprints of the host cells in response to SARS-CoV-2, SARS-CoV and MERS-CoV. Upon infection, SARS-CoV-2 induced hundreds of up-regulated host genes hallmarked by a significant cytokine production followed by virus-specific host antiviral responses. While the cytokine and antiviral responses triggered by SARS-CoV and MERS-CoV were only observed during the late stage of infection, the host antiviral responses during the SARS-CoV-2 infection were gradually enhanced lagging behind the production of cytokine. The early rapid host responses were potentially attributed to the high efficiency of SARS-CoV-2 entry into host cells, underscored by evidence of a remarkably up-regulated gene expression of TPRMSS2 soon after infection. Taken together, our findings provide novel molecular insights into the mechanisms underlying the infectivity and pathogenicity of SARS-CoV-2.

microbiology↗

Transient high glucose causes delayed wound healing by the DNMT1-mediated Ang-1/NF-κB pathway

The progression of diabetic complications does not halt despite termination of hyperglycemia, suggesting a "metabolic memory" phenomenon. However, whether metabolic memory exists in and affects the healing of diabetic wounds, as well as the underlying molecular mechanisms, remain unclear. In this study, we found that wound healing was delayed and angiogenesis was decreased in diabetic mice, despite normalization of glycemic control. Thus, we hypothesized that transient hyperglycemic spikes may be a risk factor for diabetic wound healing. We showed that transient hyperglycemia caused persistent damage to the vascular endothelium. Transient hyperglycemia directly upregulated DNMT1 expression, leading to the hypermethylation of Ang-1 and reduced Ang-1 expression, which, in turn, induced long-lasting activation of nuclear factor (NF)-{kappa}B and subsequent endothelial dysfunction. An in vivo study further showed that inhibition of DNMT1 promoted angiogenesis and accelerated diabetic wound healing by regulating the Ang-1/NF-{kappa}B signaling pathway. These results highlight the dramatic and long-lasting effects of transient hyperglycemic spikes on wound healing and suggest that DNMT1 is a novel target for diabetic vascular complications.

cell biology↗

Robust neutralization assay based on SARS-CoV-2 S-bearing vesicular stomatitis virus (VSV) pseudovirus and ACE2-overexpressed BHK21 cells

The global pandemic of Coronavirus disease 2019 (COVID-19) is a disaster for human society. A convenient and reliable in vitro neutralization assay is very important for the development of neutralizing antibodies, vaccines and other inhibitors. In this study, G protein-deficient vesicular stomatitis virus (VSVdG) bearing full-length and truncated spike (S) protein of SARS-CoV-2 were evaluated. The virus packaging efficiency of VSV-SARS-CoV-2-Sdel18 (S with C-terminal 18 amino acid truncation) is much higher than VSV-SARS-CoV-2-S. A neutralization assay for antibody screening and serum neutralizing titer quantification was established based on VSV-SARS-CoV-2-Sdel18 pseudovirus and human angiotensin-converting enzyme 2 (ACE2) overexpressed BHK21 cell (BHK21-hACE2). The experimental results can be obtained by automatically counting EGFP positive cell number at 12 hours after infection, making the assay convenient and high-throughput. The serum neutralizing titer of COVID-19 convalescent patients measured by VSV-SARS-CoV-2-Sdel18 pseudovirus assay has a good correlation with live SARS-CoV-2 assay. Seven neutralizing monoclonal antibodies targeting receptor binding domain (RBD) of SARS-CoV-2-S were obtained. This efficient and reliable pseudovirus assay model could facilitate the development of new drugs and vaccines.

microbiology↗

Discovery of peculiar cells in the peri-tumoral regions and peripheral blood of glioblastoma patients by single cell RNA-sequencing

The glioblastoma (GBM) recurrence rate is high, despite multimodal treatment including surgery, radiotherapy, chemotherapy, and immunotherapy. Most recurrences occur at the resection margin that is located outside the GBM contrast-enhancing region (C region) of magnetic resonance imaging. However, the nature of the GBM cells that lie outside the C region is unclear. We used single-cell RNA sequencing (scRNA-seq) to compare 12 samples taken from inside and outside the C region from four patients with GBM and identified a cluster of GBM cells outside the C region that exhibited fragmented CNVs in chromosomes such as 1, 10, 12 and 19 (herein termed CNV 4). A transcription factor-transcription cofactor interaction network was constructed to uncover the transcriptional regulatory mechanism of these CNV 4 GBM cells that had prognostic significance (p < 0.05). Furthermore, a sub-cluster of these CNV 4 GBM cells possessed stem cell-like properties and had tumorigenic potential. In parallel, we analyzed peripheral blood mononuclear cells (PBMCs) from four patients with GBM, three patients with epilepsy and three healthy volunteers by scRNA-seq. We identified a novel subtype of proliferative immune cells only in patients with GBM. Overall, our findings indicate that CNV 4 cells might contribute to GBM recurrence and proliferative circulating immune cells are specific to patients with GBM. This study sheds light on a neglected aspect of GBM, and opens new avenues to explore GBM recurrence and immunotherapy. SignificanceWe show that a subset of GBM cells outside the C region possess the properties of stem cell and tumorigenesis potential, which might be responsible for cancer recurrence. Besides, proliferative lymphocytes are specific to the PBMCs of patients with GBM, which could help to develop novel immunotherapy.

cancer biology↗

Characterization of Isoforms of the Ovine Granulocyte Colony Stimulating Factor

The granulocyte colony-stimulating factor (GCSF) regulates the maturation, proliferation, and differentiation of precursor cells of neutrophilic granulocytes, and has been widely studied in several species. To investigate the function of variants of sheep GCSF (sGCSF), this study compared difference in their mRNA expression levels. Both the activity and mRNA expression level of GCSFv2 were higher than those of GCSFv1. Their sequences were aligned, which showed that they had the highest homology with bovine GCSF. Then, predicted ovine GCSF isoforms and their constant C-terminals were cloned and expressed, which were stably expressed in mammalian cells. After purification, all GCSF functions were different both in vitro and in vivo, and the GCSF C-terminal was best. These results indicated that the ability to stimulate both the proliferation and differentiation of progenitor cells and to activate the maturation of neutrophils could be used for research of efficacious non-antibiotic protein drugs. Furthermore, GCSF can be used as candidate target of genetic breeding to specifically improve sheep immunity.

genetics↗

Diffusion Histology Imaging Detects and Classifies Glioblastoma Pathology Missed by Conventional Magnetic Resonance Imaging

PurposeGlioblastoma (GBM) is one of the deadliest cancers with no cure. While conventional MRI has been widely adopted for examining GBM clinically, accurate neuroimaging assessment of tumor histopathology for improved diagnosis, surgical planning, and treatment evaluation, remains an unmet need in the clinical management of GBMs. Experimental DesignWe employ a novel Diffusion Histology Imaging (DHI) approach, combining diffusion basis spectrum imaging (DBSI) and machine learning, to detect, differentiate, and quantify areas of high cellularity, tumor necrosis, and tumor infiltration in GBM. ResultsGd-enhanced T1W or hyper-intense FLAIR failed to reflect the morphological complexity underlying tumor in GBM patients. Contrary to the conventional wisdom that apparent diffusion coefficient (ADC) negatively correlates with increased tumor cellularity, we demonstrate disagreement between ADC and histologically confirmed tumor cellularity in glioblastoma specimens, whereas DBSI-derived restricted isotropic diffusion fraction positively correlated with tumor cellularity in the same specimens. By incorporating DBSI metrics as classifiers for a supervised machine learning algorithm, we accurately predicted high tumor cellularity, tumor necrosis, and tumor infiltration with 87.5%, 89.0% and 93.4% accuracy, respectively. ConclusionOur results suggest that DHI could serve as a favorable alternative to current neuroimaging techniques for guiding biopsy or surgery as well as monitoring therapeutic response in the treatment of glioblastoma. Translational RelevanceCurrent clinical diagnosis, surgical planning, and assessment of treatment response for GBM patients relies heavily on gadolinium-enhanced T1-weighted MRI, which is non-specific for tumor growth and merely reflects a disrupted blood-brain barrier. The complex tumor microenvironment and spatial heterogeneity make GBM difficult to characterize using current clinical imaging modalities. In this study, we developed a novel imaging technique to characterize and accurately predict key histological features of GBM - high tumor cellularity, tumor necrosis, and tumor infiltration. While further validation in a larger cohort of patients is needed, the current proof-of-concept approach could provide a solution to resolve important clinical questions such as the identification of true tumor progression vs. pseudoprogression or radiation necrosis.

neuroscience↗

Development of a multiparent advanced generation intercross (MAGIC) population for genetic exploitation of complex traits in Brassica juncea: glucosinolate content as an example

Multiparent advanced generation intercross (MAGIC) populations have recently been developed to allow the high-resolution mapping of complex quantitative traits. This article describes the development of one MAGIC population and verifies its potential application for mapping quantitative trait loci (QTLs) in B. juncea. The population was developed from eight founders with diverse traits and composed of 408 F6 recombinant inbred lines (RILs). To develop one rapid and simplified way for using the MAGIC population, a subset of 133 RILs as the primary mapping population were genotyped using 346 intron-length polymorphism (ILP) polymorphic markers. The population lacks significant signatures of population structure that are suitable for the analysis of complex traits. Genome-wide association mapping (GWAS) identified three major glucosinolate (GSL) QTLs of QGsl.ig01.1 on J01 for indole GSL (IG), QGsl.atg09.1 on J09 and QGsl.atg11.1 on J11 for aliphatic GSL (AG) and total GSL (TG). The candidate genes for QGsl.ig01.1, QGsl.atg09.1 and QGsl.atg11.1 are GSH1, GSL-ALK and MYB28, which are involved in converting glutamate and cysteine to{gamma} -EC, the accumulation of glucoraphanin, and the whole process of AG metabolism, respectively. One effective method for association mapping of quantitative traits in the B. juncea MAGIC population is also suggested by utilization of the remaining 275 RILs and incorporation of the novel kompetitive allele specific PCR (KASP) technique. In addition to its QTL mapping purpose, the MAGIC population could also be potentially utilized in variety development by breeders.

genetics↗

Genome-wide association analyses of multiple traits in Duroc pigs using low-coverage whole-genome sequencing strategy

High-density markers discovered in large size samples are essential for mapping complex traits at the gene-level resolution for agricultural livestock and crops. However, the unavailability of large reference panels and array designs for a target population of agricultural species limits the improvement of array-based genotype imputation. Recent studies showed very low coverage sequencing (LCS) of a large number of individuals is a cost-effective approach to discover variations in much greater detail in association studies. Here, we performed cohort-wide whole-genome sequencing at an average depth of 0.73x and identified more than 11.3 M SNPs. We also evaluated the data set and performed genome-wide association analysis (GWAS) in 2885 Duroc boars. We compared two different pipelines and selected a proper method (BaseVar/STITCH) for LCS analyses and determined that sequencing of 1000 individuals with 0.2x depth is enough for identifying SNPs with high accuracy in this population. Of the seven association signals derived from the genome-wide association analysis of the LCS variants, which were associated with four economic traits, we found two QTLs with narrow intervals were possibly responsible for the teat number and back fat thickness traits and identified 7 missense variants in a single sequencing step. This strategy (BaseVar/STITCH) is generally applicable to any populations and any species which have no suitable reference panels. These findings show that the LCS strategy is a proper approach for the construction of new genetic resources to facilitate genome-wide association studies, fine mapping of QTLs, and genomic selection, and implicate that it can be widely used for agricultural animal breeding in the future.

genetics↗

Correlated evolution of large DNA fragments in the chromatin interaction network: a case study in Arabidopsis thaliana

In eukaryotes, the three-dimensional (3D) conformation of the genome is far from random, and this nonrandom chromatin organization is strongly correlated with gene expression and protein function, which are two critical determinants of the selective constraints and evolutionary rates of genes. However, whether genes and other elements that are located close to each other in the 3D genome evolve in a coordinated way has not been investigated in any organism. To address this question, we constructed chromatin interaction networks (CINs) in Arabidopsis thaliana based on high-throughput chromosome conformation capture (Hi-C) data and demonstrated that adjacent large DNA fragments in the CIN indeed exhibit more similar levels of polymorphism and evolutionary rates than random fragment pairs. Using simulations that account for the linear distance between fragments, we proved that the 3D chromosomal organization plays a role in the observed correlated evolution. Spatially interacting fragments also exhibit more similar mutation rates and functional constraints in both coding and noncoding regions than the random expectations, indicating that the correlated evolution between 3D neighbors is a result of combined evolutionary forces. A collection of 39 genomic and epigenomic features can explain much of the variance in genetic diversity and evolutionary rates across the genome. Moreover, features that have a greater effect on the evolution of regional sequences tend to show higher similarity between neighboring fragments in the CIN, suggesting a pivotal role of epigenetic modifications and chromatin organization in determining the correlated evolution of large DNA fragments in the 3D genome.

evolutionary biology↗

RAS Internal Tandem Duplication Disrupts GAP-binding to Activate Oncogenic Signaling

Molecular testing of oncogenic RAS mutations in colorectal cancer (CRC) have led to increased identification of mutations in patients with CRC. NRAS-mutated CRC has not been well characterized because it is less common (<6%) than KRAS mutations. Here, we report a novel 10 amino acid internal tandem duplication (ITD) in NRAS, which disrupts the switch II domain, in a patient with widely disseminated CRC. Hotspot next generation sequencing of a brain metastasis identified the NRAS ITD and a TP53 missense mutation (p.P275F). Whole exome sequencing of the primary tumor and two metastatic lesions (lung and brain) confirmed that the NRAS ITD and TP53 mutation were conserved between the primary tumor and both metastatic tumors, and identified an additional pathogenic mutation in CSMD1 (a tumor suppressor gene). Structural biology and biochemical analyses demonstrated that the NRAS ITD prevented binding to GAP protein, leading to sustained RAS activation, increased interaction with RAF, and downstream MAPK activation. Additionally, we provide the first crystal structure of the RAS ITD. In conclusion, these studies indicate that the NRAS ITD was the probable primary driver mutation of this aggressive CRC. Identical or biologically similar ITDs in NRAS and KRAS may be rare drivers of CRC and other aggressive malignancies.

molecular biology↗

Mining the human tonsillar microbiota as autoimmune modulator

Palatine tonsils are important lymphoid organs featuring constant cross-talks between the commensal microorganisms and immune system, and have been implicated as critical autoimmunity origins for immune-related diseases, including rheumatoid arthritis (RA), a common autoimmune disorder. However, there was no evidence to show link between tonsillar microbiota and RA. Here, we identified a significant dysbiosis of RA tonsillar microbiota, with loss of Streptococcus salivarius and its functional molecules salivaricins (a type of antibacterial peptides). Consistent with the niche-preference, S. salivarius and salivaricins administrated intranasally or intraorally conferred prophylactic and therapeutic efficacies against experimental arthritis. Moreover, we demonstrated, for the first time, that S. salivarius and salivaricins exerted immunosuppressive capacities via inhibiting CD4+effector T cell subsets and autoantibody production in mice and human. These results uncover a communication between tonsillar microbiota and host autoimmunity, and identify the active components from tonsillar microbes in modulating immune homeostasis.\n\nOne sentence summaryTonsillar microbiota regulate host autoimmunity via antibacterial peptides

microbiology↗

Exploring the basis of 2-propenyl and 3-butenyl glucosinolate synthesis by QTL mapping and RNA-sequencing in Brassica juncea

Brassica juncea is used as a condiment, as vegetables and as an oilseed crop, especially in semiarid areas. In the present study, we constructed a genetic map using one recombinant inbred line (RIL) of B. juncea. A total of 304 ILP (intron length polymorphism) markers were mapped to 18 linkage groups designated LG01-LG18 in B. juncea. The constructed map covered a total genetic length of 1671.13 cM with an average marker interval of 5.50 cM. The QTLs for 2-propenyl glucosinolates (GSLs) colocalized with the QTLs for 3-butenyl GSLs between At1g26180 and BnapPIP1580 on LG08 in the field experiments of 2016 and 2017. These QTLs accounted for an average of 42.3% and 42.6% phenotypic variation for 2-propenyl and 3-butenyl GSLs, respectively. Furthermore, the Illumina RNA-sequencing technique was used to excavate the genes responsible for the synthesis of GSLs in the siliques of the parental lines of the RIL mapping population, because the bulk of the seed GSLs might originate from the siliques. Comparative analysis and annotation by gene ontology (GO) and kyoto encyclopedia of genes and genomes (KEGG) revealed that 324 genes were involved in GSL metabolism, among which only 24 transcripts were differentially expressed genes (DEGs). Among those DEGs, 15 genes were involved in the biosynthesis and transport of aliphatic GSLs, and their expression patterns were further validated by qRT-PCR analysis. These RNA-Seq results will be helpful for further fine mapping, gene cloning and genetic mechanisms of 2-propenyl and 3-butenyl GSLs in B. juncea.

molecular biology↗

ASCL1-regulated DARPP-32 and t-DARPP stimulate small cell lung cancer growth and neuroendocrine tumor cell survival

Small cell lung cancer (SCLC) is the most aggressive form of lung cancer, and new molecular insights are necessary for prognostic and therapeutic advances. Here we demonstrate in orthotopic mouse models that dopamine and cAMP-regulated phosphoprotein, Mr 32000 (DARPP-32) and its N-terminally truncated splice variant t-DARPP promote SCLC growth through increased proliferation, Akt/Erk-mediated survival and anti-apoptotic signaling. DARPP-32 and t-DARPP proteins are overexpressed in SCLC patient-derived tumor tissue, but virtually undetectable in physiologically normal lung. RNA sequencing analysis reveals a subset of SCLC patients with high tumoral t-DARPP expression and upregulated Notch signaling genes, including achaete-scute homologue 1 (ASCL1). We show that DARPP-32 isoforms are transcriptionally activated by ASCL1 in human SCLC cells. Taken together, we demonstrate new regulatory mechanisms of SCLC oncogenesis that suggest DARPP-32 isoforms may represent a negative prognostic indicator for SCLC and serve as a potential target for the development of new therapies.

cancer biology↗

Cross Trial Meta and Time Series Pharmacodynamic Analyses of Apremilast Effects

Finding biomarkers that provide shared link between disease severity, drug-induced pharmacodynamic effects and response status in human trials can provide number of values for patient benefits: elucidating current therapeutic mechanism-of-action, and, back-translating to fast-track development of next-generation therapeutics. Both opportunities are predicated on proactive generation of human molecular profiles that capture longitudinal trajectories before and after pharmacological intervention. Here, we present the largest plasma proteomic biomarker dataset available to-date and the corresponding analyses from placebo-controlled Phase III clinical trials of the phosphodiesterase type 4 inhibitor apremilast in psoriasis (PSOR), psoriatic arthritis (PsA), and ankylosing spondylitis (AS) from 526 subjects overall. Using approximately 150 plasma analytes tracked across three time points, we identified IL-17A and KLK-7 as biomarkers for disease severity and apremilast pharmacodynamic effect in psoriasis patients. Combined decline rate of KLK-7, PEDF, MDC and ANGPTL4 by Week 16 represented biomarkers for the responder subgroup, shedding insights into therapeutic mechanisms. In ankylosing spondylitis patients, IL-6 and LRG-1 were identified as biomarkers with concordance to disease severity. Apremilast-induced LRG-1 increase was consistent with the overall lack of efficacy in ankylosing spondylitis. Taken together, these findings expanded the mechanistic knowledge base of apremilast and provided translational foundations to accelerate future efforts including compound differentiation, combination, and repurposing.

bioinformatics↗

Transcriptome Profile Analysis of Twisted Leaf Disease Response in Susceptible Sugarcane with Narenga porphyrocoma Genetic Background

Sugarcane is an important industrial crop with a high sugar yield that has become a leading energy crop worldwide. It is widely cultivated in tropical and subtropical regions. Various diseases beset the cultivation of sugarcane. The molecular study of disease resistance in sugarcane is limited by its complicated genome. In our study, RNA-seq was employed to detect the mechanism of twisted leaf disease tolerance in modern cultivar sugarcane, which derived from Narenga porphyrocoma. We completed high-throughput transcriptomic sequencing of 12 samples, including three stages of a susceptible (NSBC1_T \"H3-8\") and an unsusceptible cultivar (NSBC1_CK \"H-19\") with two biological repeats, respectively. Using the Saccharum spontaneum genome as reference, the average mapping ratio of the clean data was over 70%. Among the differentially expressed genes between H3-8 and H3-19, we focused on the analysis of hormone pathways and resistance (R) genes. The results showed that twisted leaf disease triggers hormone networks and around 40% of R genes conditioned lower expression in the susceptible cultivar. One of the possible reasons for H3-8 being susceptible to twisted leaf disease might be the null/retarded response of R genes, especially in pre-onset stage (46% down-regulated) of pathogens infection.

genomics↗