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1.
Bioinformatics ; 38(7): 1956-1963, 2022 03 28.
Article in English | MEDLINE | ID: mdl-35015814

ABSTRACT

MOTIVATION: The advance of mass spectrometry-based technologies enabled the profiling of the phosphoproteomes of a multitude of cell and tissue types. However, current research primarily focused on investigating the phosphorylation dynamics in specific cell types and experimental conditions, whereas the phosphorylation events that are common across cell/tissue types and stable regardless of experimental conditions are, so far, mostly ignored. RESULTS: Here, we developed a statistical framework to identify the stable phosphoproteome across 53 human phosphoproteomics datasets, covering 40 cell/tissue types and 194 conditions/treatments. We demonstrate that the stably phosphorylated sites (SPSs) identified from our statistical framework are evolutionarily conserved, functionally important and enriched in a range of core signaling and gene pathways. Particularly, we show that SPSs are highly enriched in the RNA splicing pathway, an essential cellular process in mammalian cells, and frequently disrupted by cancer mutations, suggesting a link between the dysregulation of RNA splicing and cancer development through mutations on SPSs. AVAILABILITY AND IMPLEMENTATION: The source code for data analysis in this study is available from Github repository https://github.com/PYangLab/SPSs under the open-source license of GPL-3. The data used in this study are publicly available (see Section 2.8). SUPPLEMENTARY INFORMATION: Supplementary data are available at Bioinformatics online.


Subject(s)
Neoplasms , Proteome , Animals , Humans , Software , Phosphorylation , Mass Spectrometry , Neoplasms/genetics , Mammals
2.
Nucleic Acids Res ; 48(4): 1828-1842, 2020 02 28.
Article in English | MEDLINE | ID: mdl-31853542

ABSTRACT

The developmental potential of cells, termed pluripotency, is highly dynamic and progresses through a continuum of naive, formative and primed states. Pluripotency progression of mouse embryonic stem cells (ESCs) from naive to formative and primed state is governed by transcription factors (TFs) and their target genes. Genomic techniques have uncovered a multitude of TF binding sites in ESCs, yet a major challenge lies in identifying target genes from functional binding sites and reconstructing dynamic transcriptional networks underlying pluripotency progression. Here, we integrated time-resolved 'trans-omic' datasets together with TF binding profiles and chromatin conformation data to identify target genes of a panel of TFs. Our analyses revealed that naive TF target genes are more likely to be TFs themselves than those of formative TFs, suggesting denser hierarchies among naive TFs. We also discovered that formative TF target genes are marked by permissive epigenomic signatures in the naive state, indicating that they are poised for expression prior to the initiation of pluripotency transition to the formative state. Finally, our reconstructed transcriptional networks pinpointed the precise timing from naive to formative pluripotency progression and enabled the spatiotemporal mapping of differentiating ESCs to their in vivo counterparts in developing embryos.


Subject(s)
Embryonic Development/genetics , Mouse Embryonic Stem Cells/metabolism , Pluripotent Stem Cells/metabolism , Transcription Factors/genetics , Animals , Binding Sites/genetics , Cell Differentiation/genetics , Chromatin/genetics , Gene Expression Regulation, Developmental/genetics , Gene Regulatory Networks/genetics , Genome/genetics , Mice
3.
Bioinformatics ; 36(14): 4137-4143, 2020 08 15.
Article in English | MEDLINE | ID: mdl-32353146

ABSTRACT

MOTIVATION: Multi-modal profiling of single cells represents one of the latest technological advancements in molecular biology. Among various single-cell multi-modal strategies, cellular indexing of transcriptomes and epitopes by sequencing (CITE-seq) allows simultaneous quantification of two distinct species: RNA and cell-surface proteins. Here, we introduce CiteFuse, a streamlined package consisting of a suite of tools for doublet detection, modality integration, clustering, differential RNA and protein expression analysis, antibody-derived tag evaluation, ligand-receptor interaction analysis and interactive web-based visualization of CITE-seq data. RESULTS: We demonstrate the capacity of CiteFuse to integrate the two data modalities and its relative advantage against data generated from single-modality profiling using both simulations and real-world CITE-seq data. Furthermore, we illustrate a novel doublet detection method based on a combined index of cell hashing and transcriptome data. Finally, we demonstrate CiteFuse for predicting ligand-receptor interactions by using multi-modal CITE-seq data. Collectively, we demonstrate the utility and effectiveness of CiteFuse for the integrative analysis of transcriptome and epitope profiles from CITE-seq data. AVAILABILITY AND IMPLEMENTATION: CiteFuse is freely available at http://shiny.maths.usyd.edu.au/CiteFuse/ as an online web service and at https://github.com/SydneyBioX/CiteFuse/ as an R package. CONTACT: pengyi.yang@sydney.edu.au. SUPPLEMENTARY INFORMATION: Supplementary data are available at Bioinformatics online.


Subject(s)
Software , Transcriptome , Epitopes , Gene Expression Profiling , RNA , Sequence Analysis, RNA , Single-Cell Analysis
4.
Mol Syst Biol ; 16(6): e9389, 2020 06.
Article in English | MEDLINE | ID: mdl-32567229

ABSTRACT

Automated cell type identification is a key computational challenge in single-cell RNA-sequencing (scRNA-seq) data. To capitalise on the large collection of well-annotated scRNA-seq datasets, we developed scClassify, a multiscale classification framework based on ensemble learning and cell type hierarchies constructed from single or multiple annotated datasets as references. scClassify enables the estimation of sample size required for accurate classification of cell types in a cell type hierarchy and allows joint classification of cells when multiple references are available. We show that scClassify consistently performs better than other supervised cell type classification methods across 114 pairs of reference and testing data, representing a diverse combination of sizes, technologies and levels of complexity, and further demonstrate the unique components of scClassify through simulations and compendia of experimental datasets. Finally, we demonstrate the scalability of scClassify on large single-cell atlases and highlight a novel application of identifying subpopulations of cells from the Tabula Muris data that were unidentified in the original publication. Together, scClassify represents state-of-the-art methodology in automated cell type identification from scRNA-seq data.


Subject(s)
Cells/metabolism , Animals , Cluster Analysis , Databases as Topic , Humans , Leukocytes, Mononuclear/metabolism , Machine Learning , Mice , Pancreas/metabolism , Sample Size , Software
5.
Physiol Plant ; 173(4): 2376-2389, 2021 Dec.
Article in English | MEDLINE | ID: mdl-34687457

ABSTRACT

ABA is a phytohormone involved in diverse plant events such as seed germination and drought response. An F-box protein functions as a substrate receptor of the SCF complex and is responsible for ubiquitination of target proteins, triggering their subsequent degradation mediated by ubiquitin proteasome system. Here, we have isolated a gene named ARABIDOPSIS F-BOX PROTEIN HYPERSENSITIVE TO ABA 1 (AFA1) that was upregulated by ABA. AFA1 interacted with adaptor proteins of the SCF complex, implying its role as a substrate receptor of the complex. Its loss of function mutants, afa1 seedlings, exhibited ABA-hypersensitivity, including delayed germination in the presence of ABA. Moreover, loss of AFA1 led to increased drought tolerance in adult plants. Microarray data with ABA treatments indicated that 129 and 219 genes were upregulated or downregulated, respectively, by more than three times in afa1 relative to the wild type. Among the upregulated genes in afa1, the expression of 28.7% was induced by more than three times in the presence of ABA, while only 9.3% was repressed to the same extent. These data indicate that AFA1 is involved in the downregulation of many ABA-inducible genes, in accordance with the ABA-hypersensitive phenotype of afa1. Epistasis analysis showed that AFA1 could play a role upstream of ABI4 and ABI5 in the ABA signaling for germination inhibition. Collectively, our findings suggest that AFA1 is a novel F-box protein that negatively regulates ABA signaling.


Subject(s)
Arabidopsis Proteins , Arabidopsis , F-Box Proteins , Abscisic Acid/pharmacology , Arabidopsis/genetics , Arabidopsis/metabolism , Arabidopsis Proteins/genetics , Arabidopsis Proteins/metabolism , Droughts , F-Box Proteins/genetics , F-Box Proteins/metabolism , Gene Expression Regulation, Plant , Germination , Mutation , Seeds/metabolism
6.
BMC Genomics ; 20(Suppl 9): 913, 2019 Dec 24.
Article in English | MEDLINE | ID: mdl-31874628

ABSTRACT

BACKGROUND: Single-cell RNA-sequencing (scRNA-seq) is a fast emerging technology allowing global transcriptome profiling on the single cell level. Cell type identification from scRNA-seq data is a critical task in a variety of research such as developmental biology, cell reprogramming, and cancers. Typically, cell type identification relies on human inspection using a combination of prior biological knowledge (e.g. marker genes and morphology) and computational techniques (e.g. PCA and clustering). Due to the incompleteness of our current knowledge and the subjectivity involved in this process, a small amount of cells may be subject to mislabelling. RESULTS: Here, we propose a semi-supervised learning framework, named scReClassify, for 'post hoc' cell type identification from scRNA-seq datasets. Starting from an initial cell type annotation with potentially mislabelled cells, scReClassify first performs dimension reduction using PCA and next applies a semi-supervised learning method to learn and subsequently reclassify cells that are likely mislabelled initially to the most probable cell types. By using both simulated and real-world experimental datasets that profiled various tissues and biological systems, we demonstrate that scReClassify is able to accurately identify and reclassify misclassified cells to their correct cell types. CONCLUSIONS: scReClassify can be used for scRNA-seq data as a post hoc cell type classification tool to fine-tune cell type annotations generated by any cell type classification procedure. It is implemented as an R package and is freely available from https://github.com/SydneyBioX/scReClassify.


Subject(s)
RNA-Seq/methods , Animals , Humans , Machine Learning , Mice , Single-Cell Analysis/methods , Software
8.
Mol Med ; 23: 24-33, 2017 Mar.
Article in English | MEDLINE | ID: mdl-28182191

ABSTRACT

miR-155 has been shown to participate in host response to infection and neuro-inflammation via negative regulation of blood-brain-barrier (BBB) integrity and T cell function. We hypothesized that miR-155 may contribute to the pathogenesis of cerebral malaria (CM). To test this hypothesis, we used a genetic approach to modulate miR-155 expression in an experimental model of cerebral malaria (ECM). In addition, an engineered endothelialized microvessel system and serum samples from Ugandan children with CM were used to examine an anti-miR-155 as a potential adjunctive therapeutic for severe malaria. Despite higher parasitemia, survival was significantly improved in miR-155-/- mice vs. wild-type littermate mice in ECM. Improved survival was associated with preservation of BBB integrity and reduced endothelial activation, despite increased levels of pro-inflammatory cytokines. Pre-treatment with antagomir-155 reduced vascular leak induced by human CM sera in an ex vivo endothelial microvessel model. These data provide evidence supporting a mechanistic role for miR-155 in host response to malaria via regulation of endothelial activation, microvascular leak and BBB dysfunction in CM.

9.
Biochem Biophys Res Commun ; 491(2): 285-290, 2017 09 16.
Article in English | MEDLINE | ID: mdl-28735869

ABSTRACT

Although DWD HYPERSENSITIVE TO UV-B 1 (DHU1) is reported to be a negative regulator in UV-B mediated cellular responses, its detailed role in UV-B signaling is still elusive. To further understand the action mechanism of DHU1 in UV-B response, physical and genetic interactions of DHU1 with various UV-B signaling components were investigated. Yeast two hybrid assay results suggested that DHU1 directly interacts with COP1 and RUP1, implying a functional connection with both COP1 and RUP1. In spite of the physical association between DHU1 and COP1, loss of DHU1 did not affect protein stability of COP1. Epistatic analysis showed that the functional loss of both DHU1 and UVR8 leads to alleviation of UV-B hypersensitivity displayed in dhu1-1. Moreover, phenotypic studies with dhu1-1 cop1-6 and dhu1-1 hy5-215 revealed that COP1 and HY5 are epistatic to DHU1, indicating that UV-B hypersensitivity of dhu1-1 requires both COP1 and HY5. In the case of dhu1-1 rup1-1, UV-B responsiveness was similar to that of both dhu1-1 and rup1-1, implying that DHU1 and RUP1 are required for each other's function. Collectively, these results show that the role of DHU1 as a negative regulator in UV-B response may be derived from its direct interaction with COP1 by sequestering COP1 from the active UVR8-COP1 complex, resulting in a decrease in the COP1 population that positively participates in UV-B signaling together with UVR8. Furthermore, this inhibitory role of DHU1 in UV-B signaling is likely to be functionally connected to RUP1. This study will serve as a platform to further understand more detailed action mechanism of DHU1 in UV-B response and DHU1-mediated core UV-B signaling in Arabidopsis.


Subject(s)
Arabidopsis Proteins/genetics , Arabidopsis/radiation effects , Gene Expression Regulation, Plant , Light Signal Transduction , Ubiquitin-Protein Ligases/genetics , Arabidopsis/genetics , Arabidopsis/growth & development , Arabidopsis/metabolism , Arabidopsis Proteins/metabolism , Basic-Leucine Zipper Transcription Factors/genetics , Basic-Leucine Zipper Transcription Factors/metabolism , Chromosomal Proteins, Non-Histone/genetics , Chromosomal Proteins, Non-Histone/metabolism , Epistasis, Genetic , Gene Expression Regulation, Developmental , Nuclear Proteins/genetics , Nuclear Proteins/metabolism , Plants, Genetically Modified , Protein Binding , Protein Interaction Mapping , Protein Isoforms/genetics , Protein Isoforms/metabolism , Protein Stability , Seedlings/genetics , Seedlings/growth & development , Seedlings/metabolism , Seedlings/radiation effects , Seeds/genetics , Seeds/growth & development , Seeds/metabolism , Two-Hybrid System Techniques , Ubiquitin-Protein Ligases/metabolism , Ultraviolet Rays
10.
PLoS Pathog ; 11(9): e1005140, 2015 Sep.
Article in English | MEDLINE | ID: mdl-26402732

ABSTRACT

The in utero environment profoundly impacts childhood neurodevelopment and behaviour. A substantial proportion of pregnancies in Africa are at risk of malaria in pregnancy (MIP) however the impact of in utero exposure to MIP on fetal neurodevelopment is unknown. Complement activation, in particular C5a, may contribute to neuropathology and adverse outcomes during MIP. We used an experimental model of MIP and standardized neurocognitive testing, MRI, micro-CT and HPLC analysis of neurotransmitter levels, to test the hypothesis that in utero exposure to malaria alters neurodevelopment through a C5a-C5aR dependent pathway. We show that malaria-exposed offspring have persistent neurocognitive deficits in memory and affective-like behaviour compared to unexposed controls. These deficits were associated with reduced regional brain levels of major biogenic amines and BDNF that were rescued by disruption of C5a-C5aR signaling using genetic and functional approaches. Our results demonstrate that experimental MIP induces neurocognitive deficits in offspring and suggest novel targets for intervention.


Subject(s)
Complement C5a/metabolism , Host-Parasite Interactions , Malaria/physiopathology , Neurocognitive Disorders/etiology , Neurogenesis , Pregnancy Complications, Parasitic/physiopathology , Receptor, Anaphylatoxin C5a/metabolism , Animals , Biogenic Amines/metabolism , Brain/blood supply , Brain/immunology , Brain/metabolism , Brain/pathology , Brain-Derived Neurotrophic Factor/metabolism , Cerebrovascular Circulation , Down-Regulation , Female , Fetal Development , Malaria/immunology , Malaria/metabolism , Malaria/parasitology , Male , Mice, Inbred BALB C , Mice, Knockout , Neurocognitive Disorders/immunology , Neurocognitive Disorders/metabolism , Neurocognitive Disorders/pathology , Neurons/immunology , Neurons/metabolism , Neurons/pathology , Plasmodium berghei/immunology , Plasmodium berghei/physiology , Pregnancy , Pregnancy Complications, Parasitic/immunology , Pregnancy Complications, Parasitic/metabolism , Pregnancy Complications, Parasitic/parasitology , Receptor, Anaphylatoxin C5a/genetics , Signal Transduction
11.
Plant Mol Biol ; 90(3): 303-15, 2016 Feb.
Article in English | MEDLINE | ID: mdl-26667153

ABSTRACT

To elucidate the contribution of CRL3-ABA-mediated responses, we attempted to find CRL3 substrate receptors involved in ABA signaling. One gene named ABA-HYPERSENSITIVE BTB/POZ PROTEIN 1 (AHT1) was upregulated more than 2.5 times by ABA, and its coding region possessed a BTB/POZ domain, which is the common feature of CRL3 substrate receptors. Loss of AHT1 led to retardation of the germination process, not inhibition of root growth. AHT1 transcripts also increased in response to mannitol, NaCl and drought treatments at the seedling stage and in dry seeds. High expression of AHT1 in dry seeds was inhibited by the defect of ABA signaling components such as ABI1, ABI3 and SRKs indicating that the expression of AHT1 is dependent on ABA signaling. Among bZIP transcription factors participating in ABA signaling, the losses of ABI5/DPBF1, AREB1/ABF2, EEL/DPBF4 and DPBF2/bZIP67 resulted in reduced AHT1 expression, showing that these transcription factors play a positive role in ABA-induced AHT1 expression. While loss of AHT1 did not affect the expression pattern of NCED3, ABI2, SRKs and AREB/ABF genes, it led to hyperinduction of ABI5/DPBF genes such as ABI5/DPBF1, EEL/DPBF4 and AREB3/DPBF3, which are mainly involved in seed development and germination, as well as ABA-inducible genes transactivated by ABI5. Overall, these findings indicate that AHT1 negatively regulates ABA-mediated inhibition of germination, possibly by repressing the expression of a subset of ABI5/DPBF subfamily genes, and that AHT1 may be regulated by a negative feedback process through its linkage with a part of ABI5/DPBF proteins.


Subject(s)
Arabidopsis Proteins/metabolism , Arabidopsis/metabolism , Seeds/metabolism , Abscisic Acid/pharmacology , Arabidopsis/drug effects , Arabidopsis/genetics , Arabidopsis Proteins/genetics , Basic-Leucine Zipper Transcription Factors/genetics , Basic-Leucine Zipper Transcription Factors/metabolism , Dioxygenases/genetics , Dioxygenases/metabolism , Gene Expression Regulation, Plant/drug effects , Gene Expression Regulation, Plant/genetics , Germination/drug effects , Germination/genetics , Plant Proteins/genetics , Plant Proteins/metabolism , Seeds/drug effects , Seeds/genetics
12.
Trop Med Int Health ; 21(8): 965-972, 2016 Aug.
Article in English | MEDLINE | ID: mdl-27159122

ABSTRACT

OBJECTIVE: To examine the current partnerships to improve the childhood immunisation programme in the Democratic Peoples' Republic of Korea (DPRK) in the context of the political determinants of health equity. METHODS: A literature search was conducted to identify public health collaborations with the DPRK government. Based on the amount of publicly accessible data and a shared approach in health system strengthening among the partners in immunisation programmes, the search focused on these partnerships. RESULTS: The efforts by WHO, UNICEF, GAVI and IVI with the DPRK government improved the delivery of childhood vaccines (e.g. pentavalent vaccines, inactivated polio vaccine, two-dose measles vaccine and Japanese encephalitis vaccine) and strengthened the DPRK health system by equipping health centres, and training all levels of public health personnel for VPD surveillance and immunisation service delivery. CONCLUSION: The VPD-focused programmatic activities in the DPRK have improved the delivery of childhood immunisation and have created dialogue and contact with the people of the DPRK. These efforts are likely to ameliorate the political isolation of the people of the DPRK and potentially improve global health equity.

13.
Malar J ; 14: 421, 2015 Oct 29.
Article in English | MEDLINE | ID: mdl-26510464

ABSTRACT

BACKGROUND: Severe malaria remains a major cause of childhood mortality globally. Decreased endothelial nitric oxide is associated with severe and fatal malaria. The hypothesis was that adjunctive inhaled nitric oxide (iNO) would improve outcomes in African children with severe malaria. METHODS: A randomized, blinded, placebo-controlled trial of iNO at 80 ppm by non-rebreather mask versus room air placebo as adjunctive treatment to artesunate in children with severe malaria was conducted. The primary outcome was the longitudinal course of angiopoietin-2 (Ang-2), an endothelial biomarker of malaria severity and clinical outcome. RESULTS: One hundred and eighty children were enrolled; 88 were assigned to iNO and 92 to placebo (all received IV artesunate). Ang-2 levels measured over the first 72 h of hospitalization were not significantly different between groups. The mortality at 48 h was similar between groups [6/87 (6.9 %) in the iNO group vs 8/92 (8.7 %) in the placebo group; OR 0.78, 95 % CI 0.26-2.3; p = 0.65]. Clinical recovery times and parasite clearance kinetics were similar (p > 0.05). Methaemoglobinaemia >7 % occurred in 25 % of patients receiving iNO and resolved without sequelae. The incidence of neurologic deficits (<14 days), acute kidney injury, hypoglycaemia, anaemia, and haemoglobinuria was similar between groups (p > 0.05). CONCLUSIONS: iNO at 80 ppm administered by non-rebreather mask was safe but did not affect circulating levels of Ang-2. Alternative methods of enhancing endothelial NO bioavailability may be necessary to achieve a biological effect and improve clinical outcome. TRIAL REGISTRATION: ClinicalTrials.gov NCT01255215.


Subject(s)
Anti-Infective Agents/administration & dosage , Malaria/drug therapy , Nitric Oxide/administration & dosage , Vesicular Transport Proteins/blood , Administration, Inhalation , Child , Child, Preschool , Double-Blind Method , Female , Humans , Infant , Male , Placebos/administration & dosage , Prospective Studies , Treatment Outcome
14.
Infect Immun ; 82(1): 371-9, 2014 Jan.
Article in English | MEDLINE | ID: mdl-24191300

ABSTRACT

The host immune response plays an important role in the onset and progression of cerebral malaria (CM). The complement system is an essential component of the innate immune response to malaria, and its activation generates the anaphylatoxin C5a. To test the hypothesis that C5a signaling contributes to the pathogenesis of CM, we investigated a causal role for the C5a receptors C5aR and C5L2 in a mouse model of experimental CM (ECM) induced by Plasmodium berghei ANKA infection, and using a case-control design, we examined levels of C5a in plasma samples from Ugandan children presenting with CM or uncomplicated malaria (UM). In the ECM model, C5aR(-/-) mice displayed significantly improved survival compared to their wild-type (WT) counterparts (P = 0.004), whereas C5L2(-/-) mice showed no difference in survival from WT mice. Improved survival in C5aR(-/-) mice was associated with reduced levels of the proinflammatory cytokines tumor necrosis factor (TNF) and gamma interferon (IFN-γ) and the chemokine, monocyte chemoattractant protein 1 (MCP-1) (CCL2). Furthermore, endothelial integrity was enhanced, as demonstrated by increased levels of angiopoietin-1, decreased levels of angiopoietin-2 and soluble ICAM-1, and decreased Evans blue extravasation into brain parenchyma. In the case-control study, the median levels of C5a at presentation were significantly higher in children with CM versus those in children with UM (43.7 versus 22.4 ng/ml; P < 0.001). These findings demonstrate that C5a is dysregulated in human CM and contributes to the pathogenesis of ECM via C5aR-dependent inflammation and endothelial dysfunction.


Subject(s)
Complement C5a/immunology , Malaria, Cerebral/immunology , Receptors, Chemokine/immunology , Receptors, Complement/immunology , Animals , Case-Control Studies , Child , Child, Preschool , Complement C5a/deficiency , Disease Models, Animal , Female , Humans , Infant , Inflammation/immunology , Male , Mice , Mice, Inbred C57BL , Receptor, Anaphylatoxin C5a , Receptors, Complement/deficiency , Receptors, Concanavalin A
15.
Plant Mol Biol ; 86(6): 571-83, 2014 Dec.
Article in English | MEDLINE | ID: mdl-25193399

ABSTRACT

Among T-DNA insertion mutants of various cullin4-RING ubiquitin E3 ligase (CRL4) substrate receptors, one mutant that exhibits enhanced sensitivity in response to ultraviolet-B (UV-B) illumination has been isolated and its corresponding gene has been named DWD HYPERSENSITIVE TO UV-B 1 (DHU1) in Arabidopsis. dhu1 lines showed much shorter hypocotyls than those in wild type under low doses of UV-B. Other light did not alter hypocotyl growth patterns in dhu1, indicating the hypersensitivity of dhu1 is restricted to UV-B. DHU1 was upregulated by more than two times in response to UV-B application of 1.5 µmol m(-2) s(-1), implying its possible involvement in UV-B signaling. DHU1 is able to bind to DDB1, an adaptor of CRL4; accordingly, DHU1 is thought to act as a substrate receptor of CRL4. Microarray data generated from wild-type and dhu1 under low doses of UV-B revealed that 209 or 124 genes were upregulated or downregulated by more than two times in dhu1 relative to wild type, respectively. About 23.4 % of the total upregulated genes in dhu1 were upregulated by more than five times in response to UV-B based on the AtGenExpress Visualization Tool data, while only about 1.4 % were downregulated to the same degree by UV-B, indicating that loss of DHU1 led to the overall enhancement of the upregulation of UV-B inducible genes. dhu1 also showed altered responsiveness under high doses of UV-B. Taken together, these findings indicate that DHU1 is a potent CRL4 substrate receptor that may function as a negative regulator of UV-B response in Arabidopsis.


Subject(s)
Arabidopsis Proteins/genetics , Arabidopsis/genetics , Gene Expression Regulation, Plant , Signal Transduction , Stress, Physiological , Acyltransferases/genetics , Acyltransferases/metabolism , Amino Acid Sequence , Arabidopsis/physiology , Arabidopsis/radiation effects , Arabidopsis Proteins/metabolism , Chlorophyll/metabolism , Gene Expression Profiling , Models, Biological , Molecular Sequence Data , Mutagenesis, Insertional , Oligonucleotide Array Sequence Analysis , Phenotype , Plants, Genetically Modified , Protein Binding , Two-Hybrid System Techniques , Ubiquitin-Protein Ligases/genetics , Ubiquitin-Protein Ligases/metabolism , Ultraviolet Rays , Up-Regulation
16.
BMC Immunol ; 15: 1, 2014 Jan 14.
Article in English | MEDLINE | ID: mdl-24423010

ABSTRACT

BACKGROUND: Toxic shock syndrome (TSS) is caused by an overwhelming host-mediated response to bacterial superantigens produced mainly by Staphylococcus aureus and Streptococcus pyogenes. TSS is characterized by aberrant activation of T cells and excessive release of pro-inflammatory cytokines ultimately resulting in capillary leak, septic shock, multiple organ dysfunction and high mortality rates. No therapeutic or vaccine has been approved by the U.S. Food and Drug Administration for TSS, and novel therapeutic strategies to improve clinical outcome are needed. Mesenchymal stromal (stem) cells (MSCs) are stromal cells capable of self-renewal and differentiation. Moreover, MSCs have immunomodulatory properties, including profound effects on activities of T cells and macrophages in specific contexts. Based on the critical role of host-derived immune mediators in TSS, we hypothesized that MSCs could modulate the host-derived proinflammatory response triggered by Staphylococcal enterotoxin B (SEB) and improve survival in experimental TSS. METHODS: Effects of MSCs on proinflammatory cytokines in peripheral blood were measured in wild-type C57BL/6 mice injected with 50 µg of SEB. Effects of MSCs on survival were monitored in fatal experimental TSS induced by consecutive doses of D-galactosamine (10 mg) and SEB (10 µg) in HLA-DR4 transgenic mice. RESULTS: Despite significantly decreasing serum levels of IL-2, IL-6 and TNF induced by SEB in wild-type mice, human MSCs failed to improve survival in experimental TSS in HLA-DR4 transgenic mice. Similarly, a previously described downstream mediator of human MSCs, TNF-stimulated gene 6 (TSG-6), did not significantly improve survival in experimental TSS. Furthermore, murine MSCs, whether unstimulated or pre-treated with IFNγ, failed to improve survival in experimental TSS. CONCLUSIONS: Our results suggest that the immunomodulatory effects of MSCs are insufficient to rescue mice from experimental TSS, and that mediators other than IL-2, IL-6 and TNF are likely to play critical mechanistic roles in the pathogenesis of experimental TSS.


Subject(s)
Cytokines/metabolism , Inflammation Mediators/metabolism , Mesenchymal Stem Cells/metabolism , Shock, Septic/immunology , Shock, Septic/metabolism , Staphylococcal Infections/immunology , Staphylococcal Infections/metabolism , Adipocytes/cytology , Animals , Cell Differentiation , Cytokines/blood , Disease Models, Animal , Enterotoxins/immunology , Enterotoxins/metabolism , Humans , Inflammation Mediators/blood , Male , Mesenchymal Stem Cell Transplantation , Mesenchymal Stem Cells/cytology , Mice , Shock, Septic/mortality , Staphylococcal Infections/mortality
17.
Genome Biol ; 25(1): 18, 2024 01 15.
Article in English | MEDLINE | ID: mdl-38225676

ABSTRACT

BACKGROUND: The identification of genes that vary across spatial domains in tissues and cells is an essential step for spatial transcriptomics data analysis. Given the critical role it serves for downstream data interpretations, various methods for detecting spatially variable genes (SVGs) have been proposed. However, the lack of benchmarking complicates the selection of a suitable method. RESULTS: Here we systematically evaluate a panel of popular SVG detection methods on a large collection of spatial transcriptomics datasets, covering various tissue types, biotechnologies, and spatial resolutions. We address questions including whether different methods select a similar set of SVGs, how reliable is the reported statistical significance from each method, how accurate and robust is each method in terms of SVG detection, and how well the selected SVGs perform in downstream applications such as clustering of spatial domains. Besides these, practical considerations such as computational time and memory usage are also crucial for deciding which method to use. CONCLUSIONS: Our study evaluates the performance of each method from multiple aspects and highlights the discrepancy among different methods when calling statistically significant SVGs across diverse datasets. Overall, our work provides useful considerations for choosing methods for identifying SVGs and serves as a key reference for the future development of related methods.


Subject(s)
Benchmarking , Gene Expression Profiling , Biotechnology , Cluster Analysis , Histocompatibility Testing , Transcriptome
18.
Nat Med ; 2024 Jun 18.
Article in English | MEDLINE | ID: mdl-38890530

ABSTRACT

The pathogenesis of allograft (dys)function has been increasingly studied using 'omics'-based technologies, but the focus on individual organs has created knowledge gaps that neither unify nor distinguish pathological mechanisms across allografts. Here we present a comprehensive study of human pan-organ allograft dysfunction, analyzing 150 datasets with more than 12,000 samples across four commonly transplanted solid organs (heart, lung, liver and kidney, n = 1,160, 1,241, 1,216 and 8,853 samples, respectively) that we leveraged to explore transcriptomic differences among allograft dysfunction (delayed graft function, acute rejection and fibrosis), tolerance and stable graft function. We identified genes that correlated robustly with allograft dysfunction across heart, lung, liver and kidney transplantation. Furthermore, we developed a transfer learning omics prediction framework that, by borrowing information across organs, demonstrated superior classifications compared to models trained on single organs. These findings were validated using a single-center prospective kidney transplant cohort study (a collective 329 samples across two timepoints), providing insights supporting the potential clinical utility of our approach. Our study establishes the capacity for machine learning models to learn across organs and presents a transcriptomic transplant resource that can be employed to develop pan-organ biomarkers of allograft dysfunction.

19.
Malar J ; 12: 105, 2013 Mar 19.
Article in English | MEDLINE | ID: mdl-23506269

ABSTRACT

BACKGROUND: Severe falciparum malaria (SM) pathogenesis has been attributed, in part, to deleterious systemic host inflammatory responses to infection. High mobility group box 1 (HMGB1) protein is an important mediator of inflammation implicated in sepsis pathophysiology. METHODS: Plasma levels of HMGB1 were quantified in a cohort of febrile Ugandan children with Plasmodium falciparum infection, enrolled in a prospective observational case-controlled study, using a commercial enzyme-linked immunosorbent assay. The utility of HMGB1 to distinguish severe malaria (SM; n = 70) from uncomplicated malaria (UM; n = 33) patients and fatal (n = 21) versus non-fatal (n = 82) malaria, at presentation, was examined. Receiver operating characteristic curve analysis was used to assess the prognostic accuracy of HMGB1. The ability of P. falciparum-parasitized erythrocytes to induce HMGB1 from peripheral blood mononuclear cells was assessed in vitro. The effect of an anti-HMGB1 neutralizing antibody on disease outcome was assessed in the experimental Plasmodium berghei ANKA rodent parasite model of SM. Mortality and parasitaemia was assessed daily and compared to isotype antibody-treated controls. RESULTS: Elevated plasma HMGB1 levels at presentation were significantly associated with SM and a subsequent fatal outcome in paediatric patients with P. falciparum infection. In vitro, parasitized erythrocytes induced HMGB1 release from human peripheral blood mononuclear cells. Antibody-mediated neutralization of HMGB1 in the experimental murine model of severe malaria failed to reduce mortality. CONCLUSION: These data suggest that elevated HMGB1 is an informative prognostic marker of disease severity in human SM, but do not support HMGB1 as a viable target for therapeutic intervention in experimental murine SM.


Subject(s)
Biomarkers/blood , HMGB1 Protein/blood , Malaria, Falciparum/pathology , Animals , Antibodies, Neutralizing/administration & dosage , Case-Control Studies , Child , Child, Preschool , Disease Models, Animal , Enzyme-Linked Immunosorbent Assay , Female , Humans , Immunoglobulins, Intravenous/administration & dosage , Infant , Malaria/drug therapy , Malaria/pathology , Malaria, Falciparum/mortality , Male , Mice , Mice, Inbred C57BL , Prognosis , Prospective Studies , ROC Curve , Treatment Outcome , Uganda
20.
STAR Protoc ; 4(2): 102203, 2023 Mar 29.
Article in English | MEDLINE | ID: mdl-37000617

ABSTRACT

Characterizing transcription factor (TF) genomic colocalization is essential for identifying cooperative binding of TFs in controlling gene expression. Here, we introduce a protocol for using PAD2, an interactive web application that enables the investigation of colocalization of various TFs and chromatin-regulating proteins from mouse embryonic stem cells at various functional genomic regions. We describe steps for accessing and searching the PAD2 database and selecting and submitting genomic regions. We then detail protein colocalization analysis using heatmap and ranked correlation plot. For complete details on the use and execution of this protocol, please refer to Kim et al. (2022).1.

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