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Wang, A.

Publications and source records attributed to Wang, A..

At least 253 records · Page 14Linked to original sources

Single Nucleus Multiomic Profiling Reveals Age-Dynamic Regulation of Host Genes Associated with SARS-CoV-2 Infection

Respiratory failure is the leading cause of COVID-19 death and disproportionately impacts adults more than children. Here, we present a large-scale snATAC-seq dataset (90,980 nuclei) of the human lung, generated in parallel with snRNA-seq (46,500 nuclei), from healthy donors of ~30 weeks, ~3 years and ~30 years of age. Focusing on genes implicated in SARS-CoV-2 cell entry, we observed an increase in the proportion of alveolar epithelial cells expressing ACE2 and TMPRSS2 in adult compared to young lungs. Consistent with expression dynamics, 10 chromatin peaks linked to TMPRSS2 exhibited significantly increased activity with age and harbored IRF and STAT binding sites. Furthermore, we identified 14 common sequence variants in age-increasing peaks with predicted regulatory function, including several associated with respiratory traits and TMPRSS2 expression. Our findings reveal a plausible contributor to why children are more resistant to COVID-19 and provide an epigenomic basis for transferring this resistance to older populations.

genomics↗

Scalable Surrogate Deconvolution for Identification of Partially-Observable Systems and Brain Modeling

For many biophysical systems, direct measurement of all state-variables, in - vivo is not-feasible. Thus, a key challenge in biological modeling and signal processing is to reconstruct the activity and structure of interesting biological systems from indirect measurements. These measurements are often generated by approximately linear time-invariant (LTI) dynamical interactions with the hidden system and may therefore be described as a convolution of hidden state-variables with an unknown kernel. In the current work, we present an approach termed surrogate deconvolution, to directly identify such coupled systems (i.e. parameterize models). Surrogate deconvolution reframes certain nonlinear partially-observable identification problems, which are common in neuroscience/biology, as analytical objectives that are compatible with almost any user-chosen optimization procedure. We show that the proposed technique is highly scalable, low in computational complexity, and performs competitively with the current gold-standard in partially-observable system estimation: the joint Kalman Filters (Unscented and Extended). We show the benefits of surrogate deconvolution for model identification when applied to simulations of the Local Field Potential and blood oxygen level dependent (BOLD) signal. Lastly, we demonstrate the empirical stability of Hemodynamic Response Function (HRF) kernel estimates for Mesoscale Individualized NeuroDynamic (MINDy) models of individual human brains. The recovered HRF parameters demonstrate reliable individual variation as well as a stereotyped spatial distribution, on average. These results demonstrate that surrogate deconvolution promises to enhance brain-modeling approaches by simultaneously and rapidly fitting large-scale models of brain networks and the physiological processes which generate neuroscientific measurements (e.g. hemodynamics for BOLD fMRI).

neuroscience↗

Siderophores provoke extracellular superoxide production by carbon-starving Arthrobacter strains when carbon sources recover

Superoxide and other reactive oxygen species (ROS) in the environment shape microbial communities1 and drive transformation of metals2,3 and inorganic/organic matter4,5. Taxonomically diverse bacteria and phytoplankton can produce extracellular superoxide during laboratory cultivation6-11. Understanding the physiological reasons for extracellular superoxide production by aerobes in the environment is a crucial question yet not fully solved. Here, we showed that iron-starving Arthrobacter sp. QXT-31 (referred to as A. QXT-31 hereafter) secreted a type of siderophore (deferoxamine, DFO), which provoked extracellular superoxide production by carbon-starving A. QXT-31 when carbon sources were recovered. Several other siderophores also demonstrated similar effects. RNA-Seq data hinted that DFO stripped iron from iron-bearing proteins in the electron transfer chain (ETC) of metabolically active A. QXT-31, resulting in electron leakage from the electron-rich (resulting from carbons source metabolism) ETC and superoxide production. Considering that most aerobes secrete siderophore(s)12 and often suffer from carbon starvation in the environment, certain aerobes are expected to produce extracellular superoxide when carbon source(s) recover/fluctuate, thus influencing the microbial community and cycling of many elements. In addition, an artificial iron-chelator (diethylenetriamine pentaacetic acid, DTPA) was widely used in microbial superoxide quantification. Our results showed that DTPA provoked superoxide production by A. QXT-31 and highlighted its potential interference in microbial superoxide quantification.

microbiology↗

A Clock-Driven Neural Network Critical for Arousal

The daily cycling of sleep and arousal states is among the most prominent biological rhythms under circadian control. While much is known about the core circadian clock1,2, how this clock tunes sleep and arousal remains poorly understood3. In Drosophila, we previously characterized WIDE AWAKE (WAKE), a clock-output molecule that promotes sleep at night4,5. Here, we show that the function of WAKE in regulating circadian-dependent neural excitability and arousal is conserved in mice. mWake+ cells are found in the suprachiasmatic nucleus (SCN) and dorsomedial hypothalamus (DMH). mWakeDMH neurons drive wakefulness and exhibit rhythmic spiking, with greater firing during the night vs the day. Loss of mWAKE leads to increased spiking of mWake+ SCN and DMH neurons and prominent behavioural arousal, specifically during the night. Single-cell sequencing, imaging, and patch-clamp experiments reveal that mWakeDMH neurons constitute a glutamatergic/GABAergic population that projects widely, receives neuromodulatory input, and acts on neuromodulatory neurons. Strikingly, broad chemogenetic silencing of mWake+ cells leads to profound loss of behavioural responsiveness and low amplitude, low frequency electroencephalography waveforms. These findings suggest that the genetic mechanisms regulating circadian control of sleep and arousal are conserved across >500 million years of evolution and define a clock-regulated neural network critical for arousal.

neuroscience↗

Brassinosteroids Suppress Ethylene Biosynthesis via Transcription Factor BZR1 in Pear and Apple Fruit

The plant hormone ethylene is important for the ripening of climacteric fruit, such as pear (Pyrus ussuriensis), and the brassinosteroid (BR) class of phytohormones affects ethylene biosynthesis during ripening, although via an unknown molecular mechanism. Here, we observed that exogenous BR treatment suppressed ethylene production during pear fruit ripening, and that the expression of the transcription factor PuBZR1 was enhanced by epibrassinolide (EBR) treatment during pear fruit ripening. PuBZR1 was shown to interact with PuACO1, which converts 1-aminocyclopropane-1-carboxylic acid (ACC) to ethylene, and suppress its activity. We also observed that BR-activated PuBZR1 bound to the promoters of PuACO1 and of PuACS1a, which encodes ACC synthase, and directly suppressed their transcription. Moreover, PuBZR1 suppressed the expression of transcription factor PuERF2 by binding its promoter, and PuERF2 bound to the promoters of PuACO1 and PuACS1a. We concluded that PuBZR1 indirectly suppresses the transcription of PuACO1 and PuACS1a through its regulation of PuERF2. Ethylene production and the expression profiles of the corresponding apple (Malus domestica) homologs showed similar changes following EBR treatment. Together, these results suggest that BR-activated BZR1 suppresses ACO1 activity and the expression of ACO1 and ACS1a, thereby reducing ethylene production during pear and apple fruit ripening. This likely represents a conserved mechanism by which exogenous BR suppresses ethylene biosynthesis during climacteric fruit ripening. One-sentence summaryBR-activated BZR1 suppresses ACO1 activity and expression of ACO1 and ACS1a, which encode two ethylene biosynthesis enzymes, thereby reducing ethylene production during pear and apple fruit ripening.

plant biology↗

Glial type specific regulation of CNS angiogenesis by HIFα-activated different signaling pathways

The mechanisms by which oligodendroglia modulate CNS angiogenesis remain elusive. Previous in vitro data suggest that oligodendroglia regulate CNS endothelial cell proliferation and blood vessel formation through hypoxia inducible factor alpha (HIF)-activated Wnt (but not VEGF) signaling. Using in vivo genetic models, we show that HIF in oligodendroglia is necessary and sufficient for angiogenesis independent of CNS regions. At the molecular level, HIF stabilization in oligodendroglia does not perturb Wnt signaling but remarkably activates VEGF. At the functional level, genetically blocking oligodendroglia-derived VEGF but not Wnt significantly decreases oligodendroglial HIF-regulated CNS angiogenesis. Interestingly, blocking astroglia-derived Wnt signaling reduces astroglial HIF-regulated CNS angiogenesis. Together, our in vivo data clearly demonstrate that oligodendroglial HIF regulates CNS angiogenesis through Wnt-independent and VEGF-dependent signaling. Our findings represent an alternative mechanistic understanding of CNS angiogenesis by postnatal glial cells and unveil a glial cell type-dependent HIF-Wnt axis in regulating CNS vessel formation.

neuroscience↗

A variant in SMOC2, inhibiting BMP signaling by competitively binding to BMPR1B, causes multiple epiphyseal dysplasia

Previously study showed that SMOC, a matricellular protein, inhibits BMP signaling downstream of its receptor via activation of mitogen-activated protein kinase (MAPK) signaling. In our study, exome sequencing revealed a missense mutation (c.1076T>G, p.Leu359Arg) in EC domain of SMOC2 in a Chinese family with multiple epiphyseal disease (MED). The pathogenicity of this SMOC2 variant was verified by Smoc2L359R/L359R knock-in mice. Of note, decreasing phosphorylation of SMAD1/5/9 was detected in growth plates and primary chondrocytes from Smoc2L359R/L359R mice. Furthermore, binding affinity of mutant SMOC2 with collagen IX and HSPG in the extracellular matrix of cartilage were reduced while binding affinity with BMPRIB was intact. In addition, in contrast to previously results, that SMOC2 cannot antagonize BMP activity in the presence of a constitutively activated BMP receptor. These results support that SMOC2 with p.Leu359Arg variant act as an antagonist of canonical BMP pathway by competitively binding with BMP receptors.

genomics↗

CD4+ follicular helper-like T cells are key players in anti-tumor immunity

To determine the nature of CD4+ T cells that provide help for generating robust anti-tumor CD8+ cytotoxic T cell (CTL) responses, we profiled the transcriptomes of patient-matched CD4+ and CD8+ T cells present in the tumor micro-environment (TME) and analyzed them jointly using integrated weighted gene correlation network analysis. We found the follicular helper T cell (TFH) program in CD4+ T cells was strongly associated with proliferation and tissue-residency in CD8+ CTLs. Single-cell analysis demonstrated the presence of TFH-like cells and features linked to cytotoxic function and their provision of CD8+ T cell help. Tumor-infiltrating TFH-like cells expressed PD-1 and were enriched in tumors following checkpoint blockade, suggesting that they may respond to anti-PD-1 therapy. Adoptive transfer or induction of TFH cells in mouse models resulted in augmented CD8+ CTL responses and impairment of tumor growth, indicating an important role of TFH-like CD4+ T cells in anti-tumor immunity.

immunology↗

Delving below the species level to characterize the ecological diversity within the global virome: An exploration of West Nile Virus

Efforts to describe the diversity of viruses have largely focused on classifying viruses at the species level. However, substantial ecological diversity, both in virulence level and host range, is known within virus species. Here we demonstrate a proof of concept for easily discovering ecological diversity within a virus species taxon. We have focused on the West Nile Virus to take advantage of its broad host range in nature. We produced a genome-based phylogeny of world diversity of WNV and then used Ecotype Simulation 2 to hypothesize demarcation of genomes into 69 putative ecotypes (ecologically distinct populations), based only on clustering of genome sequences. Then we looked for evidence of ecological divergence among ecotypes based on differences in host bird associations within the Connecticut-New York region. Our results indicated significant heterogeneity among ecotypes for their associations with different bird hosts. Ecological diversity within other zoonotic viruses could be easily discovered using this approach. Opportunities for extending this line of research to human associations of virus ecotypes are limited by missing geographic metadata on human samples.

microbiology↗

A conserved translation factor is required for optimal synthesis of a membrane protein family in mycobacteria

Ribosomes require the activity of associated GTPases to synthesize proteins. Despite strong evolutionary conservation, the roles of many of these remain unknown. For example, LepA (also known as elongation factor 4) is a ribosome-associated GTPase found in bacteria, mitochondria, and chloroplasts, yet its physiological contribution to cell survival is not clear. Recently, we found that loss of lepA in Mycobacterium smegmatis (Msm) altered tolerance to rifampin, a drug that targets a non-ribosomal cellular process. To uncover the determinants of LepA-mediated drug tolerance, we characterized the whole-cell proteomes and transcriptomes of a lepA deletion mutant relative to a wild-type strain. We find that LepA is important for the steady-state abundance of an outer membrane porin, which is integral to nutrient uptake and drug susceptibility. Loss of LepA leads to a decreased amount of porin in the membrane, resulting in the drug tolerance phenotype of the lepA mutant. LepA control requires a sequence motif in the 5 region of the porin transcript. Thus, LepA controls the abundance of specific proteins, likely through its activity during translation. ImportanceOur understanding of how ribosomes properly synthesis an entire cellular proteome, in all its complexity, is still evolving. Ribosomal GTPases are often highly conserved, but the roles of many are not well understood. For example, elongation factor 4, or LepA, is a ribosome-associated GTPase conserved across bacteria, mitochondria, and chloroplasts. Using whole-cell proteomics and RNA-sequencing of wild type and a lepA deletion mutant, we find that LepA improves translation of mycobacterial porins in a message-specific manner. As porins play a key role in cell wall permeability, loss of LepA produces a plethora of phenotypic changes. These findings underline the problem of building proteins into a complex cell wall, such as that of mycobacteria, and point to a solution in the use of GTPases such as LepA, that have evolved to aid in specific protein synthesis.

microbiology↗

Spleen Transcriptome Analysis of C57BL/6 Mouse in Response to Hot Water Extract from Spent Mushroom Substrate of Ganoderma lucidum and Cyclophosphamide

Previously, we have indicated that Hot Water Extract (HWE) from Spent Mushroom Substrate (SMS) of Ganoderma lucidum enhanced immune function of normal mice, and improved antioxidant activity and enhanced immune function of immunosuppression mice induced by cyclophosphamide (Cy). Here we performed the high throughput RNA sequencing strategy using Illumina HiSeq 2000 to characterize the spleen transcriptome from normal (CK1), HWE-treated (CK2), Cy-treated (CY) and both high dose HWE and Cy-treated mice (CH). From the RNA Sequencing, total mapped reads of map to Gene in CK1, CK2, CY and CH was 54 759 942, 54 678 926, 44 728 132 and 54 006 596, respectively. And gene expression was significantly different among CK1 and CK2, CY and CH. Compared with CK1, the gene expression of Ugt1a6b was down-regulated in CK2 after HWE treated. In addition, compared with CY, multiple tumor suppressor or tumorigenesis genes were down-regulated, such as Cdkn1a, Cdkn1b, Mapk10, Vash1, and Tnc and other genes in CK2 and CH. Taken together, our study highlighted the spleen transcriptome profiles of C57BL/6 mouse in response to HWE from SMS of G. lucidum and Cy, and indicated that HWE can improve the immune function of the mouse and accelerated the recovery of immunosuppression in Cy-treated mice.

bioinformatics↗

Input dose differentiation by NF-κB

Cells receive a wide range of dynamic signaling inputs during immune regulation, but how gene regulatory networks measure and interpret such dynamic inputs is not understood. Here, we used microfluidic live-cell analysis and mathematical modeling to study how NF-{kappa}B pathway in single-cells responds to time-varying immune inputs such as increasing, decreasing or fluctuating cytokine signals. Surprisingly, we found that NF-{kappa}B acts as a differentiator, responding strictly to the absolute difference in cytokine concentration, and not to the concentration itself. Our analyses revealed that negative feedbacks by the regulatory proteins A20 and I{kappa}B enable dose differentiation by providing short-term memory of prior cytokine level and continuously resetting kinase cycling and receptor levels. Investigation of NF-{kappa}B target gene expression showed that cells create unique transcriptional responses under different dynamic cytokine profiles. Our results demonstrate how cells use simple network motifs and transcription factor dynamics to efficiently extract information from complex signaling environments.

systems biology↗

LSD1-mediated enhancer silencing enables endocrine cell development through attenuation of retinoic acid signalling.

Developmental progression depends on temporally defined changes in gene expression mediated by transient exposure of lineage intermediates to signals in the progenitor niche. To identify a possible contribution of cell-intrinsic epigenetic mechanisms to signal-induced transcriptional responses, we manipulated the signalling environment and activity of the histone demethylase LSD1 during stepwise differentiation of gut tube intermediates into pancreatic endocrine cells. Analysis of enhancer and transcriptome landscapes revealed that lineage progression and endocrine cell differentiation requires LSD1-mediated silencing of transiently active retinoic acid (RA)-induced enhancers. In the absence of LSD1, early RA-responsive enhancers remain partially active despite RA removal, resulting in perduring expression of RA-induced genes, and failure to progress in development. Our findings identify LSD1-mediated enhancer silencing as a cell-intrinsic epigenetic feedback mechanism by which the duration of the transcriptional response to a developmental signal is limited. Given LSD1s requirement in numerous developmental contexts, the here-described mechanism would be broadly relevant.

developmental biology↗

Abbreviated assessment of psychopathology in patients with suspected seizure disorders

PurposePsychopathology is common in patients undergoing investigation for seizure-related disorders. Psychometric examination using self-report instruments, such as the SCL-90-R, can assist diagnosis. The SCL-90-R, however, is a lengthy instrument and might not be tolerated by all patients. We assessed several abbreviated forms of the SCL-90-R in patients undergoing video encephalographic monitoring (VEM).\n\nMethod687 patients completed the SCL-90-R and scores were computed for the full SCL-90-R and five abbreviated forms. Correlations and mean differences were computed between different forms. Classification accuracy was assessed via receiver operating characteristic (ROC) curves, and measurements models were examined using confirmatory factor analysis (CFA).\n\nResultsAll abbreviated forms were strongly correlated with the SCL-90-R for general psychopathology (r = .93 - .99), depression (r = .89 - .95), anxiety (r = .97 - .98), psychosis (r = .95 - .99), and obsessive-compulsive symptoms (r = .97). Classification performance was similar across forms for depression and anxiety, with high negative predictive values (.90 - .94) and lower positive predictive values (.34 - .38). Classification performance for psychotic and obsessive-compulsive disorders was poor. Differences were observed between the full SCL-90-R and its abbreviated forms across most domains (d = 0.00 - 0.65). The published measurement model was most strongly validated for the SCL-27, SCL-14, and the SCL-K-9.\n\nConclusionsThese five SCL-90-R abbreviated forms show high convergent validity with the full version. In patients undergoing investigation for seizure-related disorders, the BSI or BSI-18 are most appropriate where screening for both depression and anxiety is required. The SCL-K-9 is appropriate when only a single measure of global psychological distress is required. None of the instruments were able to detect psychotic or obsessive-compulsive symptoms with great accuracy. Caution should be exercised when making direct comparisons across the different forms.

neuroscience↗

Circulating bacterial DNA as a tool towards non-invasive biomarkers for colorectal cancer and adenoma

ObjectiveThe gut microbiota is closely associated with colorectal neoplasia. While most metagenomics studies utilized fecal samples, circulating microbial DNA in colorectal neoplasia patients remained unexplored. This study aimed to characterize microbial DNA in plasma samples and build a machine learning model for colorectal neoplasia early detection.\n\nDesignWe performed whole genome sequencing of plasma samples from 25 colorectal cancer (CRC) patients, 10 colorectal adenoma (CRA) patients and 22 healthy controls (HC). Microbial DNA was obtained by removing the host genome and relative abundance was measured by mapping reads into microbial genomes. Significant biomarker species were identified in the discovery cohort and built into a random forest model, which was tested in the validation cohort.\n\nResultsIn the discovery cohort, there were 127 significant species between CRC patients and HC. Based on the random forest model, 28 species were selected from the discovery cohort (AUC=0.944) and yielded an AUC of 1 in the validation cohort. Interestingly, relative abundance of most biomarker species in CRA patients were between CRC patients and HC with a trend towards CRC patients. Furthermore, pathway enrichment analysis also showed similar pattern where CRA patients had intermediate relative abundance of significant pathways compared to CRC patients and HC. Finally, species network analysis revealed that CRC and HC displayed distinct patterns of species association.\n\nConclusionsWe demonstrated characteristic alteration of circulating bacterial DNA in colorectal neoplasia patients. The predictive model accurately distinguished CRC and CRA from HC, suggesting the utility of circulating bacterial biomarkers as a non-invasive tool for colorectal neoplasia screening and early diagnosis.

cancer biology↗

Integrating exposure knowledge and serum suspect screening as a new approach to biomonitoring: An application in firefighters and office workers

BackgroundWomen firefighters are exposed to recognized and probable carcinogens, yet there are few studies of chemical exposures and associated health concerns, such as breast cancer. Biomonitoring often requires a priori selection of compounds to be measured, and so may not detect important, lesser known, exposures.\n\nObjectivesThe Women Firefighters Biomonitoring Collaborative (WFBC) created a biological sample archive and conducted a general suspect screen (GSS) to address this data gap.\n\nMethodsUsing liquid chromatography-quadrupole time-of-flight mass spectrometry (LC-QTOF/MS) we sought to identify candidate chemicals of interest in serum samples from 83 women firefighters (FF) and 79 office workers (OW) in San Francisco. Through the GSS approach we identified chemical peaks by matching accurate mass from serum samples against a custom chemical database of 740 slightly polar phenolic and acidic compounds, including many of relevance to firefighting or breast cancer etiology. We then selected chemicals for confirmation based on a priori criteria: 1) detection frequency or peak area differences between OW and FF; 2) evidence of mammary carcinogenicity, estrogenicity, or genotoxicity; and 3) not currently measured in large biomonitoring studies.\n\nResultsWe detected 620 chemicals that matched 300 molecular formulas in the WFBC database, including phthalate metabolites, phosphate flame retardant metabolites, phenols, pesticides, nitro-and nitroso-compounds, and per- and polyfluoroalkyl substances. The average number of chemicals from the database that were detected in participants was 72 and 70 in FF and OW, respectively. We confirmed 8 of the 20 prioritized suspect chemicals -including two alkylphenols, ethyl paraben, BPF, PFOSAA, benzophenone-3, benzyl p-hydroxybenzoate, and triphenyl phosphate--by running a matrix spike of the reference standards and using m/z, retention time and the confirmation of at least two fragment ions as criteria for matching.\n\nConclusionGSS provides a powerful high-throughput approach to identify and prioritize novel chemicals for biomonitoring and health studies.

epidemiology↗

A network of microRNAs acts to promote cell cycle exit and differentiation of human pancreatic endocrine cells

Pancreatic endocrine cell differentiation is orchestrated by transcription factors that operate in a gene regulatory network to activate endocrine lineage genes and repress lineage-inappropriate genes. MicroRNAs (miRNAs) are important modulators of gene expression, yet their role in endocrine cell differentiation has not been explored system-wide. Here we characterize miRNA-regulatory networks active in human endocrine cell differentiation by combining small RNA sequencing, miRNA overexpression experiments, and network modeling approaches. This analysis identifies Let-7g, Let-7a, miR-200a, and miR-375 as endocrine-enriched miRNAs with high impact on driving endocrine differentiation-associated gene expression changes. These miRNAs target different sets of transcription factors, which converge on a network of genes involved in cell cycle regulation. When expressed in human embryonic stem cell-derived pancreatic progenitors these miRNAs induce cell cycle exit and promote endocrine cell differentiation. Our study delineates the role of miRNAs in human endocrine cell differentiation and identifies miRNAs that could facilitate endocrine cell reprogramming.

developmental biology↗

Single-molecule long-read sequencing reveals the chromatin basis of gene expression

Genome-wide chromatin accessibility and nucleosome occupancy profiles have been widely investigated, while the long-range dynamics remains poorly studied at the single-cell level. Here we present a new experimental approach MeSMLR-seq (methyltransferase treatment followed by single-molecule long-read sequencing) for long-range mapping of nucleosomes and chromatin accessibility at single DNA molecules, and thus achieve comprehensive-coverage characterization of the corresponding heterogeneity. We applied MeSMLR-seq to haploid yeast, where single DNA molecules represent single cells, and thus we could investigate the combinatorics of many (up to 356) nucleosomes at long range in single cells. We illustrated the differential organization principles of nucleosomes surrounding transcription start site for silently- and actively-transcribed genes, at the single-cell level and in the long-range scale. The heterogeneous patterns of chromatin statuses spanning multiple genes were phased. Together with single-cell RNA-seq data, we quantitatively revealed how chromatin accessibility correlated with gene transcription positively in a highly-heterogeneous scenario. Moreover, we quantified the openness of promoters and investigated the coupled chromatin changes of adjacent genes at single DNA molecules during transcription reprogramming.

bioinformatics↗