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1.
ACS Appl Mater Interfaces ; 16(15): 18959-18970, 2024 Apr 17.
Article in English | MEDLINE | ID: mdl-38569111

ABSTRACT

Fe-based Prussian blue (Fe-PB) analogues have emerged as promising cathode materials for sodium-ion batteries, owing to their cost-effectiveness, high theoretical capacity, and environmental friendliness. However, their practical application is hindered by [Fe(CN)6] defects, negatively impacting capacity and cycle stability. This work reports a hollow layered Fe-PB composite material using 1,3,5-benzenetricarboxylic acid (BTA) as a chelating and etching agent by the hydrothermal method. Compared to benzoic acid, our approach significantly reduces defects and enhances the yield of Fe-PB. Notably, the hollow layered structure shortens the diffusion path of sodium ions, enhances the activity of low-spin Fe in the Fe-PB lattice, and mitigates volume changes during Na-ion insertion/extraction into/from Fe-PB. As a sodium-ion battery cathode, this hollow layered Fe-PB exhibits an impressive initial capacity of 95.9 mAh g-1 at a high current density of 1 A g-1. Even after 500 cycles, it still maintains a considerable discharge capacity of 73.1 mAh g-1, showing a significantly lower capacity decay rate (0.048%) compared to the control sample (0.089%). Moreover, the full cell with BTA-PB-1.6 as the cathode and HC as the anode provides a considerable energy density of 312.2 Wh kg-1 at a power density of 291.0 W kg-1. This research not only enhances the Na storage performance of Fe-PB but also increases the yield of products obtained by hydrothermal methods, providing some technical reference for the production of PB materials using the low-yield hydrothermal method.

2.
Nat Protoc ; 18(9): 2671-2698, 2023 09.
Article in English | MEDLINE | ID: mdl-37567932

ABSTRACT

Chemical modifications of transcripts with a 5' cap occur in all organisms and function in many aspects of RNA metabolism. To facilitate analysis of RNA caps, we developed a systems-level mass spectrometry-based technique, CapQuant, for accurate and sensitive quantification of the cap epitranscriptome. The protocol includes the addition of stable isotope-labeled cap nucleotides (CNs) to RNA, enzymatic hydrolysis of endogenous RNA to release CNs, and off-line enrichment of CNs by ion-pairing high-pressure liquid chromatography, followed by a 17 min chromatography-coupled tandem quadrupole mass spectrometry run for the identification and quantification of individual CNs. The total time required for the protocol can be up to 7 d. In this approach, 26 CNs can be quantified in eukaryotic poly(A)-tailed RNA, bacterial total RNA and viral RNA. This protocol can be modified to analyze other types of RNA and RNA from in vitro sources. CapQuant stands out from other methods in terms of superior specificity, sensitivity and accuracy, and it is not limited to individual caps nor does it require radiolabeling. Thanks to its unique capability of accurately and sensitively quantifying RNA caps on a systems level, CapQuant can reveal both the RNA cap landscape and the transcription start site distribution of capped RNA in a broad range of settings.


Subject(s)
RNA Caps , Tandem Mass Spectrometry , RNA Caps/genetics , RNA, Messenger/genetics , Chromatography, High Pressure Liquid , RNA, Viral/genetics , RNA, Bacterial
3.
ACS Appl Mater Interfaces ; 14(38): 43308-43318, 2022 Sep 28.
Article in English | MEDLINE | ID: mdl-36107796

ABSTRACT

The Fe-based Prussian blue (Fe-PB) composite is considered as one of the most potential cathode materials for sodium-ion batteries because of its abundant iron resources and high theoretical capacity. However, the crystal water and vacancy in the Fe-PB structure will lead to poor capacity and cycle stability. In this work, a Cu-modified Fe-PB composite (FeCu-PB@CuO) is successfully prepared through regulating the Fe-PB structure by Cu doping and engineering the surface by CuO coating. The density functional theory calculation results confirm that Cu preferentially replaces FeHS in the Fe-PB lattice and Cu doping reduces the bandgap. Our experiment results reveal that CuO coating can provide more active sites, inhibit side reactions, and potentially enhance the activity of FeHS. Due to the synergistic effect of Cu doping and CuO coating, FeCu-PB@CuO has a considerable initial discharge capacity of 123.5 mAh g-1 at 0.1 A g-1. In particular, at 2 A g-1, it delivers an impressive initial capacity of 84.3 mAh g-1, and the capacity decreasing rate of each cycle is only 0.02% over 1500 cycles. Therefore, the synergistic modification strategy of metal ion doping and metal oxide coating has tremendous application potential and can be extended to other electrode materials.

4.
Sci China Life Sci ; 65(9): 1824-1839, 2022 09.
Article in English | MEDLINE | ID: mdl-35508790

ABSTRACT

Signal transducers and activators of transcription 5 (Stat5) is known to engage in regulating the differentiation and effector function of various subsets of T helper cells. However, how Stat5 regulates the antitumor activity of tumor-infiltrating CD4+ T cells is largely unknown. Here, we showed that mice with specific deletion of Stat5 in CD4+ T cells were less susceptible to developing subcutaneous and lung metastatic B16 melanoma with CD4+ tumor-infiltrating lymphocytes (TILs) remolding. Especially, we confirmed that Stat5-deficient CD4+ naïve T cells were prone to polarization of two subtypes of Th17 cells: IFN-γ+ and IFN-γ- Th17 cells, which exhibited increased anti-melanoma activity through enhanced activation of Notch1 pathway compared with wild type Th17 cells. Our study therefore revealed a novel function of Stat5 in regulating tumor-specific Th17 cell differentiation and function in melanoma. This study also provided a new possibility for targeting Stat5 and other Th17-associated pathways to develop novel immunotherapies for melanoma patients.


Subject(s)
Melanoma , T-Lymphocytes, Helper-Inducer , Animals , CD4-Positive T-Lymphocytes/metabolism , Cell Differentiation , Lymphocytes, Tumor-Infiltrating , Melanoma/metabolism , Mice , Mice, Inbred C57BL , T-Lymphocytes, Helper-Inducer/metabolism , T-Lymphocytes, Helper-Inducer/pathology
5.
ACS Appl Mater Interfaces ; 14(4): 5506-5513, 2022 Feb 02.
Article in English | MEDLINE | ID: mdl-35072463

ABSTRACT

Iron-based Prussian blue (FeHCF) has great application potential in the large-scale production of sodium-ion (Na+) batteries because of its high theoretical capacity and abundant Fe ore resources. However, the Fe(CN)6 vacancies and crystal water seriously affect the electrochemical performance. Herein, a Cu-doped FeHCF (Cu-FeHCF) cathode material is successfully prepared directly by a coprecipitation method. After Cu doping, the monoclinic structure and the quasi-cubic morphology are retained, but the electrochemical performance is significantly improved. In addition to few Fe(CN)6 vacancies and low crystal water, the improved performance is also related to the enhanced electrochemical activity of low-spin Fe and the stabilizing effect of Cu on the crystal structure. Moreover, Cu doping also controls the side reaction to a certain extent. As a result, after Cu doping, the initial discharge capacity is enhanced from 107.9 to 127.4 mA h g-1 at 100 mA g-1, especially the capacities contributed by low-spin Fe increase from 30.0, 21.7, and 16.7 mA h g-1 to 48.8, 45.4, and 43.7 mA h g-1 for the first three cycles, respectively. Even at 2 A g-1, Cu-FeHCF still has a promising initial capacity of 82.3 mA h g-1 and only a 0.047% capacity decay rate for each cycle over 500 cycles. Therefore, Cu-FeHCF shows excellent application potential in the field of Na+ energy storage batteries.

6.
Commun Biol ; 3(1): 642, 2020 11 03.
Article in English | MEDLINE | ID: mdl-33144666

ABSTRACT

The liver and gallbladder are among the most important internal organs derived from the endoderm, yet the development of the liver and gallbladder in the early embryonic stages is not fully understood. Using a transgenic Foxa2eGFP reporter mouse line, we performed single-cell full-length mRNA sequencing on endodermal and hepatic cells isolated from ten embryonic stages, ranging from E7.5 to E15.5. We identified the embryonic liver developmental trajectory from gut endoderm to hepatoblasts and characterized the transcriptome of the hepatic lineage. More importantly, we identified liver primordium as the nascent hepatic progenitors with both gut and liver features and documented dynamic gene expression during the epithelial-hepatic transition (EHT) at the stage of liver specification during E9.5-11.5. We found six groups of genes switched on or off in the EHT process, including diverse transcripitional regulators that had not been previously known to be expressed during EHT. Moreover, we identified and revealed transcriptional profiling of gallbladder primordium at E9.5. The present data provides a high-resolution resource and critical insights for understanding the liver and gallbladder development.


Subject(s)
Hepatocyte Nuclear Factor 3-beta/metabolism , Liver/embryology , Animals , Cells, Cultured , Gene Expression Regulation, Developmental/physiology , Green Fluorescent Proteins/genetics , Green Fluorescent Proteins/metabolism , Hepatocyte Nuclear Factor 3-beta/genetics , Liver/metabolism , Mice , Sequence Analysis, RNA , Single-Cell Analysis
7.
Sci Rep ; 10(1): 14246, 2020 08 28.
Article in English | MEDLINE | ID: mdl-32859970

ABSTRACT

Cholesterol 25-hydroxylase (CH25H) encodes the enzyme that converts cholesterol to 25-hydroxycholesterol (25-HC). 25-HC has been demonstrated to be involved in the pathogenesis of inflammatory bowel disease. However, the role of CH25H in experimental colitis remains unknown. Dextran sulfate sodium (DSS)-induced colitis was monitored in wild type and Ch25h-/- mice in 8-week-old male for 7 days by assessment of body weight, histology, inflammatory cellular infiltration, and colon length. The function of CH25H was investigated using loss-of-function and gain-of-function such as Ch25h-deficient mice, supplementation with exogenous 25-HC and treatment of 25-HC into Caco2 and HCT116 colonic epithelial cells. Ch25h-/- mice with DSS-induced colitis exhibited aggravated injury, including higher clinical colitis scores, severe injury of the epithelial barrier, lower tight junction protein levels and higher levels of IL-6. Supplementation with exogenous 25-HC ameliorated disease symptoms and reduced the extent of damage in DSS-induced colitis, which was characterized by lower colon damage, higher tight junction protein expression, significantly decreased local and systemic production of pro-inflammatory cytokines IL-6. In Caco2 and HCT116 cells, 25-HC induced tight junction genes expression in colon cancer epithelial cells. These effects of CH25H were obtained by promoting ATF3 expression. Taken together, our findings reveal a protective role for 25-HC in DSS-induced colitis and the ability of CH25H to maintain epithelial gut barrier function through ATF3 expression. Supplementation with exogenous 25-HC ameliorates disease symptoms, which provides a new therapeutic strategy for ulcerative colitis.


Subject(s)
Colitis/drug therapy , Intestinal Mucosa/drug effects , Steroid Hydroxylases/pharmacology , Animals , Caco-2 Cells , Colitis/chemically induced , Colitis/physiopathology , Colitis, Ulcerative/pathology , Colon/metabolism , Colonic Neoplasms/pathology , Cytokines/metabolism , Dextran Sulfate/pharmacology , Disease Models, Animal , Epithelial Cells/metabolism , Gastrointestinal Microbiome/drug effects , HCT116 Cells , Humans , Intestinal Mucosa/metabolism , Intestines/microbiology , Male , Mice , Mice, Inbred C57BL , Mice, Knockout , Permeability/drug effects , Steroid Hydroxylases/metabolism , Tight Junction Proteins/metabolism , Tight Junctions/metabolism
9.
Nucleic Acids Res ; 47(20): e130, 2019 11 18.
Article in English | MEDLINE | ID: mdl-31504804

ABSTRACT

Chemical modification of transcripts with 5' caps occurs in all organisms. Here, we report a systems-level mass spectrometry-based technique, CapQuant, for quantitative analysis of an organism's cap epitranscriptome. The method was piloted with 21 canonical caps-m7GpppN, m7GpppNm, GpppN, GpppNm, and m2,2,7GpppG-and 5 'metabolite' caps-NAD, FAD, UDP-Glc, UDP-GlcNAc, and dpCoA. Applying CapQuant to RNA from purified dengue virus, Escherichia coli, yeast, mouse tissues, and human cells, we discovered new cap structures in humans and mice (FAD, UDP-Glc, UDP-GlcNAc, and m7Gpppm6A), cell- and tissue-specific variations in cap methylation, and high proportions of caps lacking 2'-O-methylation (m7Gpppm6A in mammals, m7GpppA in dengue virus). While substantial Dimroth-induced loss of m1A and m1Am arose with specific RNA processing conditions, human lymphoblast cells showed no detectable m1A or m1Am in caps. CapQuant accurately captured the preference for purine nucleotides at eukaryotic transcription start sites and the correlation between metabolite levels and metabolite caps.


Subject(s)
Epigenesis, Genetic , RNA Caps/chemistry , RNA Processing, Post-Transcriptional , Sequence Analysis, RNA/methods , Transcriptome , Animals , Cells, Cultured , Dengue Virus , Female , Humans , Mice , Mice, Inbred C57BL , RNA Caps/genetics , RNA, Viral/chemistry , RNA, Viral/genetics , Saccharomyces cerevisiae
10.
J Vis Exp ; (139)2018 09 10.
Article in English | MEDLINE | ID: mdl-30247479

ABSTRACT

The granulocyte-macrophage-colony-stimulating factor (GM-CSF)-producing T helper (THGM) cell is a newly identified T helper cell subset that predominantly secretes GM-CSF without producing interferon (IFN)γ or interleukin (IL)-17 and is found to play an essential role in the autoimmune neuroinflammation. A method of isolation of naive CD4+ T cells from a single-cell suspension of splenocytes and THGM cell generation from naive CD4+ T cells would be a useful technique in the study of T cell-mediated immunity and autoimmune diseases. Here we describe a method that differentiates mouse naive CD4+ T cells into THGM cells promoted by IL-7. The outcome of the differentiation was assessed by the analysis of the cytokines expression using different techniques, including intracellular cytokine staining combined with flow cytometry, a quantitative real-time polymerase chain reaction (PCR), and enzyme-linked immunosorbent assays (ELISA). Using the THGM differentiation protocol as described here, about 55% of the cells expressed GM-CSF with a minimal expression of IFNα or IL-17. The predominant expression of GM-CSF by THGM cells was further confirmed by the analysis of the expression of GM-CSF, IFNα, and IL-17 at both mRNA and protein levels. Thus, this method can be used to differentiate naive CD4+ T cells to THGM cells in vitro, which will be useful in the study of THGM cell biology.


Subject(s)
Cell Differentiation , Granulocyte-Macrophage Colony-Stimulating Factor/biosynthesis , T-Lymphocytes, Helper-Inducer/cytology , T-Lymphocytes, Helper-Inducer/metabolism , Animals , Interferon-alpha/metabolism , Interleukin-17/metabolism , Mice
11.
Stem Cells Int ; 2018: 8632950, 2018.
Article in English | MEDLINE | ID: mdl-30254684

ABSTRACT

Studies have demonstrated that STAT3 is essential in maintaining self-renewal of embryonic stem cells (ESCs) and modulates ESC differentiation. However, there is still lack of direct evidence on STAT3 functions in ESCs and embryogenesis because constitutive STAT3 knockout (KO) mouse is embryonic lethal at E6.5-E7.5, prior to potential functional role in early development can be assessed. Therefore, in this study, two inducible STAT3 ESC lines were established, including the STAT3 knockout (InSTAT3 KO) and pSTAT3 overexpressed (InSTAT3 CA) using Tet-on inducible system in which STAT3 expression can be strictly controlled by doxycycline (Dox) stimulation. Through genotyping, deletion of STAT3 alleles was detected in InSTAT3 KO ESCs following 24 hours Dox stimulation. Western blot also showed that pSTAT3 and STAT3 protein levels were significantly reduced in InSTAT3 KO ESCs while dominantly elevated in InSTAT3 CA ECSs upon Dox stimulation. Likewise, it was found that STAT3-null ESCs would affect the differentiation of ESCs into mesoderm and cardiac lineage. Taken together, the findings of this study indicated that InSTAT3 KO and InSTAT3 CA ESCs could provide a new tool to clarify the direct targets of STAT3 and its role in ESC maintenance, which will facilitate the elaboration of the mechanisms whereby STAT3 maintains ESC pluripotency and regulates ESC differentiation during mammalian embryogenesis.

12.
J Pathol ; 246(1): 89-102, 2018 09.
Article in English | MEDLINE | ID: mdl-29926931

ABSTRACT

Characterising the activated oncogenic signalling that leads to advanced breast cancer is of clinical importance. Here, we showed that SET domain, bifurcated 1 (SETDB1), a histone H3 lysine 9 methyltransferase, is aberrantly expressed and behaves as an oncogenic driver in breast cancer. SETDB1 enhances c-MYC and cyclin D1 expression by promoting the internal ribosome entry site (IRES)-mediated translation of MYC/CCND1 mRNA, resulting in prominent signalling of c-MYC to promote cell cycle progression, and provides a growth/self-renewal advantage to breast cancer cells. The activated c-MYC-BMI1 axis is essential for SETDB1-mediated breast tumourigenesis, because silencing of either c-MYC or BMI1 profoundly impairs the enhanced growth/colony formation conferred by SETDB1. Furthermore, c-MYC directly binds to the SETDB1 promoter region and enhances its transcription, suggesting a positive regulatory interplay between SETDB1 and c-MYC. In this study, we identified SETDB1 as a prominent oncogene and characterised the underlying mechanism whereby SETDB1 drives breast cancer, providing a therapeutic rationale for targeting SETDB1-BMI1 signalling in breast cancer. Copyright © 2018 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.


Subject(s)
Breast Neoplasms/enzymology , Carcinogenesis/metabolism , Polycomb Repressive Complex 1/metabolism , Protein Methyltransferases/metabolism , Proto-Oncogene Proteins c-myc/metabolism , Animals , Breast Neoplasms/genetics , Breast Neoplasms/pathology , Carcinogenesis/genetics , Carcinogenesis/pathology , Cell Cycle , Cell Proliferation , Cyclin D1/genetics , Cyclin D1/metabolism , Estrogen Receptor alpha/genetics , Estrogen Receptor alpha/metabolism , Gene Expression Regulation, Neoplastic , HEK293 Cells , Histone-Lysine N-Methyltransferase , Humans , MCF-7 Cells , Mice , Oncogenes , Polycomb Repressive Complex 1/genetics , Protein Methyltransferases/genetics , Proto-Oncogene Proteins c-myc/genetics , Signal Transduction , Transcriptional Activation
13.
Stem Cell Reports ; 10(6): 1807-1820, 2018 06 05.
Article in English | MEDLINE | ID: mdl-29706498

ABSTRACT

The capacity of embryonic stem cells (ESCs) to differentiate into all lineages of mature organism is precisely regulated by cellular signaling factors. STAT3 is a crucial transcription factor that plays a central role in maintaining ESC identity. However, the underlying mechanism by which STAT3 directs differentiation is still not completely understood. Here, we show that STAT3 positively regulates gene expression of methyltransferase-like protein 8 (Mettl8) in mouse ESCs. We found that METTL8 is dispensable for pluripotency but affects ESC differentiation. Subsequently, we discovered that METTL8 interacts with Mapkbp1's mRNA, which is an intermediate factor in c-Jun N-terminal kinase (JNK) signaling, and inhibits the translation of the mRNA. Thereby, METTL8 prohibits the activation of JNK signaling and enhances the differentiation of mouse ESCs. Collectively, our study uncovers a STAT3 target, Mettl8, which regulates mouse ESC differentiation via JNK signaling.


Subject(s)
Cell Differentiation , Embryonic Stem Cells/cytology , Embryonic Stem Cells/metabolism , MAP Kinase Signaling System , Methyltransferases/metabolism , STAT3 Transcription Factor/metabolism , Animals , Cellular Reprogramming/genetics , Gene Expression Regulation, Developmental , Gene Knockdown Techniques , Intracellular Signaling Peptides and Proteins/genetics , Mice , Models, Biological , Mouse Embryonic Stem Cells/cytology , Mouse Embryonic Stem Cells/metabolism , Protein Binding , RNA, Messenger/genetics , RNA, Messenger/metabolism , Transcription, Genetic
14.
Cell Death Differ ; 25(4): 663-678, 2018 03.
Article in English | MEDLINE | ID: mdl-29238071

ABSTRACT

Axonal injury is a common feature of central nervous system insults. Upregulation of amyloid precursor protein (APP) is observed following central nervous system neurotrauma and is regarded as a marker of central nervous system axonal injury. However, the underlying mechanism by which APP mediates neuronal death remains to be elucidated. Here, we used mouse optic nerve axotomy (ONA) to model central nervous system axonal injury replicating aspects of retinal ganglion cell (RGC) death in optic neuropathies. APP and APP intracellular domain (AICD) were upregulated in retina after ONA and APP knockout reduced Tuj1+ RGC loss. Pathway analysis of microarray data combined with chromatin immunoprecipitation and a luciferase reporter assay demonstrated that AICD interacts with the JNK3 gene locus and regulates JNK3 expression. Moreover, JNK3 was found to be upregulated after ONA and to contribute to Tuj1+ RGC death. APP knockout reduced the ONA-induced enhanced expression of JNK3 and phosphorylated JNK (pJNK). Gamma-secretase inhibitors prevented production of AICD, reduced JNK3 and pJNK expression similarly, and protected Tuj1+ RGCs from ONA-induced cell death. Together these data indicate that ONA induces APP expression and that gamma-secretase cleavage of APP releases AICD, which upregulates JNK3 leading to RGC death. This pathway may be a novel target for neuronal protection in optic neuropathies and other forms of neurotrauma.


Subject(s)
Amyloid beta-Protein Precursor/biosynthesis , Gene Expression Regulation, Enzymologic , Mitogen-Activated Protein Kinase 10/biosynthesis , Optic Nerve Diseases/metabolism , Optic Nerve/metabolism , Retinal Ganglion Cells/metabolism , Up-Regulation , Amyloid beta-Protein Precursor/genetics , Animals , Axotomy , Mice , Mice, Mutant Strains , Mitogen-Activated Protein Kinase 10/genetics , Optic Nerve/pathology , Optic Nerve Diseases/genetics , Optic Nerve Diseases/pathology , Retinal Ganglion Cells/pathology
15.
J Biol Chem ; 292(35): 14695-14703, 2017 09 01.
Article in English | MEDLINE | ID: mdl-28655767

ABSTRACT

Chemical RNA modifications are central features of epitranscriptomics, highlighted by the discovery of modified ribonucleosides in mRNA and exemplified by the critical roles of RNA modifications in normal physiology and disease. Despite a resurgent interest in these modifications, the biochemistry of 3-methylcytidine (m3C) formation in mammalian RNAs is still poorly understood. However, the recent discovery of trm141 as the second gene responsible for m3C presence in RNA in fission yeast raises the possibility that multiple enzymes are involved in m3C formation in mammals as well. Here, we report the discovery and characterization of three distinct m3C-contributing enzymes in mice and humans. We found that methyltransferase-like (METTL) 2 and 6 contribute m3C in specific tRNAs and that METTL8 only contributes m3C to mRNA. MS analysis revealed that there is an ∼30-40% and ∼10-15% reduction, respectively, in METTL2 and -6 null-mutant cells, of m3C in total tRNA, and primer extension analysis located METTL2-modified m3C at position 32 of tRNAThr isoacceptors and tRNAArg(CCU) We also noted that METTL6 interacts with seryl-tRNA synthetase in an RNA-dependent manner, suggesting a role for METTL6 in modifying serine tRNA isoacceptors. METTL8, however, modified only mRNA, as determined by biochemical and genetic analyses in Mettl8 null-mutant mice and two human METTL8 mutant cell lines. Our findings provide the first evidence of the existence of m3C modification in mRNA, and the discovery of METTL8 as an mRNA m3C writer enzyme opens the door to future studies of other m3C epitranscriptomic reader and eraser functions.


Subject(s)
Cytidine/analogs & derivatives , Liver/metabolism , Methyltransferases/metabolism , RNA Processing, Post-Transcriptional , RNA, Messenger/metabolism , RNA, Transfer/metabolism , Animals , Cell Line , Cytidine/metabolism , Humans , Isoenzymes/genetics , Isoenzymes/metabolism , Liver/enzymology , Methylation , Methyltransferases/antagonists & inhibitors , Methyltransferases/chemistry , Methyltransferases/genetics , Mice , Mice, Knockout , Mice, Mutant Strains , Mutation , RNA Interference , RNA, Transfer, Arg/metabolism , RNA, Transfer, Ser/metabolism , RNA, Transfer, Thr/metabolism , Recombinant Fusion Proteins/chemistry , Recombinant Fusion Proteins/metabolism , Serine-tRNA Ligase/chemistry , Serine-tRNA Ligase/metabolism , Substrate Specificity
16.
Circulation ; 133(1): 48-61, 2016 Jan 05.
Article in English | MEDLINE | ID: mdl-26628621

ABSTRACT

BACKGROUND: ß-Adrenergic receptors (ßARs) play paradoxical roles in the heart. On one hand, ßARs augment cardiac performance to fulfill the physiological demands, but on the other hand, prolonged activations of ßARs exert deleterious effects that result in heart failure. The signal transducer and activator of transcription 3 (STAT3) plays a dynamic role in integrating multiple cytokine signaling pathways in a number of tissues. Altered activation of STAT3 has been observed in failing hearts in both human patients and animal models. Our objective is to determine the potential regulatory roles of STAT3 in cardiac ßAR-mediated signaling and function. METHODS AND RESULTS: We observed that STAT3 can be directly activated in cardiomyocytes by ß-adrenergic agonists. To follow up this finding, we analyzed ßAR function in cardiomyocyte-restricted STAT3 knockouts and discovered that the conditional loss of STAT3 in cardiomyocytes markedly reduced the cardiac contractile response to acute ßAR stimulation, and caused disengagement of calcium coupling and muscle contraction. Under chronic ß-adrenergic stimulation, Stat3cKO hearts exhibited pronounced cardiomyocyte hypertrophy, cell death, and subsequent cardiac fibrosis. Biochemical and genetic data supported that Gαs and Src kinases are required for ßAR-mediated activation of STAT3. Finally, we demonstrated that STAT3 transcriptionally regulates several key components of ßAR pathway, including ß1AR, protein kinase A, and T-type Ca(2+) channels. CONCLUSIONS: Our data demonstrate for the first time that STAT3 has a fundamental role in ßAR signaling and functions in the heart. STAT3 serves as a critical transcriptional regulator for ßAR-mediated cardiac stress adaption, pathological remodeling, and heart failure.


Subject(s)
Heart/physiology , Receptors, Adrenergic, beta/physiology , STAT3 Transcription Factor/physiology , Adrenergic beta-Agonists/pharmacology , Animals , Cell Line , Heart/drug effects , Male , Mice , Mice, Inbred C57BL , Mice, Knockout , Myocytes, Cardiac/drug effects , Myocytes, Cardiac/physiology , Organ Culture Techniques
17.
Dev Biol ; 400(1): 1-9, 2015 Apr 01.
Article in English | MEDLINE | ID: mdl-25536399

ABSTRACT

In the early mouse embryo, a specialized population of extraembryonic visceral endoderm (VE) cells called the distal VE (DVE) arises at the tip of the egg cylinder stage embryo and then asymmetrically migrates to the prospective anterior, recruiting additional distal cells. Upon migration these cells, called the anterior VE (AVE), establish the anterior posterior (AP) axis by restricting gastrulation-inducing signals to the opposite pole. The Nodal-signaling pathway has been shown to have a critical role in the generation and migration of the DVE/AVE. The Nodal gene is expressed in both the VE and in the pluripotent epiblast, which gives rise to the germ layers. Previous findings have provided conflicting evidence as to the relative importance of Nodal signaling from the epiblast vs. VE for AP patterning. Here we show that conditional mutagenesis of the Nodal gene specifically within the VE leads to reduced Nodal expression levels in the epiblast and incomplete or failed DVE/AVE migration. These results support a required role for VE Nodal to maintain normal levels of expression in the epiblast, and suggest signaling from both VE and epiblast is important for DVE/AVE migration.


Subject(s)
Body Patterning/physiology , Cell Movement/physiology , Endoderm/physiology , Gene Expression Regulation, Developmental/physiology , Germ Layers/metabolism , Nodal Protein/metabolism , Signal Transduction/physiology , Animals , Endoderm/cytology , Galactosides , Genes, Reporter/genetics , In Situ Hybridization , Indoles , Mice , Mice, Inbred C57BL , Microscopy, Fluorescence , Mutagenesis , Nodal Protein/genetics
18.
Cell Res ; 24(12): 1387-402, 2014 Dec.
Article in English | MEDLINE | ID: mdl-25412660

ABSTRACT

T helper (TH)-cell subsets, such as TH1 and TH17, mediate inflammation in both peripheral tissues and central nervous system. Here we show that STAT5 is required for T helper-cell pathogenicity in autoimmune neuroinflammation but not in experimental colitis. Although STAT5 promotes regulatory T cell generation and immune suppression, loss of STAT5 in CD4+ T cells resulted in diminished development of experimental autoimmune encephalomyelitis (EAE), a mouse model of multiple sclerosis. Our results showed that loss of encephalitogenic activity of STAT5-deficient autoreactive CD4+ T cells was independent of IFN-γ or interleukin 17 (IL-17) production, but was due to the impaired expression of granulocyte-macrophage colony-stimulating factor (GM-CSF), a crucial mediator of T-cell pathogenicity. We further showed that IL-7-activated STAT5 promotes the generation of GM-CSF-producing CD4+ T cells, which were preferentially able to induce more severe EAE than TH17 or TH1 cells. Consistent with GM-CSF-producing cells being a distinct subset of TH cells, the differentiation program of these cells was distinct from that of TH17 or TH1 cells. We further found that IL-3 was secreted in a similar pattern as GM-CSF in this subset of TH cells. In conclusion, the IL-7-STAT5 axis promotes the generation of GM-CSF/IL-3-producing TH cells. These cells display a distinct transcriptional profile and may represent a novel subset of T helper cells which we designate as TH-GM.


Subject(s)
Encephalomyelitis, Autoimmune, Experimental/immunology , Granulocyte-Macrophage Colony-Stimulating Factor/immunology , STAT5 Transcription Factor/immunology , T-Lymphocytes, Helper-Inducer/immunology , Animals , Colitis/genetics , Colitis/immunology , Colitis/pathology , Encephalomyelitis, Autoimmune, Experimental/genetics , Encephalomyelitis, Autoimmune, Experimental/pathology , Gene Deletion , Granulocyte-Macrophage Colony-Stimulating Factor/analysis , Interleukin-7/analysis , Interleukin-7/immunology , Mice , Mice, Inbred C57BL , Mice, Knockout , STAT5 Transcription Factor/analysis , STAT5 Transcription Factor/genetics , T-Lymphocytes, Helper-Inducer/metabolism , T-Lymphocytes, Helper-Inducer/pathology
19.
PLoS One ; 9(8): e104597, 2014.
Article in English | MEDLINE | ID: mdl-25157689

ABSTRACT

Signal transducers and activators of transcription (STAT) proteins are key signalling molecules in metazoans, implicated in various cellular processes. Increased research in the field has resulted in the accumulation of STAT sequence and structure data, which are scattered across various public databases, missing extensive functional annotations, and prone to effort redundancy because of the dearth of community sharing. Therefore, there is a need to integrate the existing sequence, structure and functional data into a central repository, one that is enriched with annotations and provides a platform for community contributions. Herein, we present STATdb (publicly available at http://statdb.bic.nus.edu.sg/), the first integrated resource for STAT sequences comprising 1540 records representing the known STATome, enriched with existing structural and functional information from various databases and literature and including manual annotations. STATdb provides advanced features for data visualization, analysis and prediction, and community contributions. A key feature is a meta-predictor to characterise STAT sequences based on a novel classification that integrates STAT domain architecture, lineage and function. A curation policy workflow has been devised for regulated and structured community contributions, with an update policy for the seamless integration of new data and annotations.


Subject(s)
Databases, Protein , STAT Transcription Factors/chemistry , Amino Acid Sequence , Animals , Humans , Internet , Molecular Sequence Data , STAT Transcription Factors/classification , Systems Integration
20.
Stem Cells Dev ; 23(10): 1062-73, 2014 May 15.
Article in English | MEDLINE | ID: mdl-24380431

ABSTRACT

Embryonic stem cells (ESCs) derived from the inner cell mass (ICM) of blastocysts are pluripotent. Pluripotency is maintained by a transcriptional network in which Oct4 and Nanog are master regulators. Notably, several zinc finger transcription factors have important roles in this network. Patz1, a BTB/POZ-domain-containing zinc finger protein, is expressed at higher levels in the ICM relative to the trophectoderm. However, its function in pluripotency has been poorly studied. Here, we show that Patz1 is an important regulator of pluripotency in ESCs. Patz1 RNAi, chromatin immunoprecipitation (ChIP), and reporter assays indicate that Patz1 directly regulates Pou5f1 and Nanog. Global transcriptome changes upon Patz1 knockdown largely involve upregulation of apoptotic genes and downregulation of cell cycle and cellular metabolism genes. Patz1 ChIP sequencing further identified more than 5,000 binding sites of Patz1 in mouse genome, from which two binding motifs were extracted. Further, gene ontology analysis of genes associated with the binding sites displays enrichment for proximity to developmental genes. In addition, embryoid body assays suggest that Patz1 represses developmental genes. Together, these results propose that Patz1 is important for ESC pluripotency.


Subject(s)
Embryonic Stem Cells/metabolism , Gene Expression Regulation/physiology , Neoplasm Proteins/metabolism , Pluripotent Stem Cells/metabolism , Repressor Proteins/metabolism , Animals , Cell Line , Embryoid Bodies/cytology , Embryoid Bodies/metabolism , Embryonic Stem Cells/cytology , Homeodomain Proteins/biosynthesis , Mice , Nanog Homeobox Protein , Octamer Transcription Factor-3/biosynthesis , Pluripotent Stem Cells/cytology , Response Elements/physiology
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