ABSTRACT
Gasdermins are a family of structurally related proteins originally described for their role in pyroptosis. Gasdermin B (GSDMB) is currently the least studied, and while its association with genetic susceptibility to chronic mucosal inflammatory disorders is well established, little is known about its functional relevance during active disease states. Herein, we report increased GSDMB in inflammatory bowel disease, with single-cell analysis identifying epithelial specificity to inflamed colonocytes/crypt top colonocytes. Surprisingly, mechanistic experiments and transcriptome profiling reveal lack of inherent GSDMB-dependent pyroptosis in activated epithelial cells and organoids but instead point to increased proliferation and migration during in vitro wound closure, which arrests in GSDMB-deficient cells that display hyper-adhesiveness and enhanced formation of vinculin-based focal adhesions dependent on PDGF-A-mediated FAK phosphorylation. Importantly, carriage of disease-associated GSDMB SNPs confers functional defects, disrupting epithelial restitution/repair, which, altogether, establishes GSDMB as a critical factor for restoration of epithelial barrier function and the resolution of inflammation.
Subject(s)
Epithelial Cells/metabolism , Epithelial Cells/pathology , Inflammatory Bowel Diseases/metabolism , Inflammatory Bowel Diseases/pathology , Pore Forming Cytotoxic Proteins/metabolism , Pyroptosis , Base Sequence , Case-Control Studies , Cell Adhesion/drug effects , Cell Adhesion/genetics , Cell Membrane/drug effects , Cell Membrane/metabolism , Cell Movement/drug effects , Cell Movement/genetics , Cell Proliferation/drug effects , Cell Proliferation/genetics , Epithelial Cells/drug effects , Focal Adhesion Protein-Tyrosine Kinases/metabolism , HEK293 Cells , HT29 Cells , Humans , Inflammatory Bowel Diseases/genetics , Methotrexate/pharmacology , Mutation/genetics , Phosphorylation/drug effects , Polymorphism, Single Nucleotide/genetics , Pyroptosis/drug effects , Pyroptosis/genetics , Reproducibility of Results , Transcriptome/drug effects , Transcriptome/genetics , Up-Regulation/drug effects , Wound Healing/drug effects , Wound Healing/geneticsABSTRACT
Chronic inflammation is a common feature of obesity, with elevated cytokines such as interleukin-1 (IL-1) in the circulation and tissues. Here, we report an unconventional IL-1R-MyD88-IRAK2-PHB/OPA1 signaling axis that reprograms mitochondrial metabolism in adipocytes to exacerbate obesity. IL-1 induced recruitment of IRAK2 Myddosome to mitochondria outer membranes via recognition by TOM20, followed by TIMM50-guided translocation of IRAK2 into mitochondria inner membranes, to suppress oxidative phosphorylation and fatty acid oxidation, thereby attenuating energy expenditure. Adipocyte-specific MyD88 or IRAK2 deficiency reduced high-fat-diet-induced weight gain, increased energy expenditure and ameliorated insulin resistance, associated with a smaller adipocyte size and increased cristae formation. IRAK2 kinase inactivation also reduced high-fat diet-induced metabolic diseases. Mechanistically, IRAK2 suppressed respiratory super-complex formation via interaction with PHB1 and OPA1 upon stimulation of IL-1. Taken together, our results suggest that the IRAK2 Myddosome functions as a critical link between inflammation and metabolism, representing a novel therapeutic target for patients with obesity.
Subject(s)
Adipocytes/immunology , Inflammation/immunology , Interleukin-1 Receptor-Associated Kinases/metabolism , Interleukin-1/metabolism , Mitochondrial Membranes/metabolism , Obesity/immunology , Adipocytes/pathology , Animals , Cells, Cultured , Humans , Interleukin-1 Receptor-Associated Kinases/genetics , Male , Mice , Mice, Knockout , Myeloid Differentiation Factor 88/genetics , Myeloid Differentiation Factor 88/metabolism , Oxidative Phosphorylation , Prohibitins , Protein Transport , Receptors, Interleukin-1/metabolism , Signal TransductionABSTRACT
The molecular basis of the incomplete penetrance of monogenic disorders is unclear. We describe here eight related individuals with autosomal recessive TIRAP deficiency. Life-threatening staphylococcal disease occurred during childhood in the proband, but not in the other seven homozygotes. Responses to all Toll-like receptor 1/2 (TLR1/2), TLR2/6, and TLR4 agonists were impaired in the fibroblasts and leukocytes of all TIRAP-deficient individuals. However, the whole-blood response to the TLR2/6 agonist staphylococcal lipoteichoic acid (LTA) was abolished only in the index case individual, the only family member lacking LTA-specific antibodies (Abs). This defective response was reversed in the patient, but not in interleukin-1 receptor-associated kinase 4 (IRAK-4)-deficient individuals, by anti-LTA monoclonal antibody (mAb). Anti-LTA mAb also rescued the macrophage response in mice lacking TIRAP, but not TLR2 or MyD88. Thus, acquired anti-LTA Abs rescue TLR2-dependent immunity to staphylococcal LTA in individuals with inherited TIRAP deficiency, accounting for incomplete penetrance. Combined TIRAP and anti-LTA Ab deficiencies underlie staphylococcal disease in this patient.
Subject(s)
Antibodies, Monoclonal/administration & dosage , Lipopolysaccharides/metabolism , Membrane Glycoproteins/deficiency , Receptors, Interleukin-1/deficiency , Staphylococcal Infections/genetics , Staphylococcal Infections/immunology , Teichoic Acids/metabolism , Adaptive Immunity , Child , Female , Fibroblasts/metabolism , Humans , Immunity, Innate , Lipopolysaccharides/immunology , Macrophages/immunology , Male , Membrane Glycoproteins/analysis , Membrane Glycoproteins/genetics , Monocytes/metabolism , Myeloid Differentiation Factor 88/metabolism , Pedigree , Phagocytes/metabolism , Point Mutation , Protein Isoforms/analysis , Protein Isoforms/genetics , Receptors, Interleukin-1/analysis , Receptors, Interleukin-1/genetics , Staphylococcal Infections/drug therapy , Teichoic Acids/immunology , Toll-Like Receptor 2/metabolism , Toll-Like Receptors/agonists , Toll-Like Receptors/metabolismABSTRACT
IL-17 is a highly versatile pro-inflammatory cytokine crucial for a variety of processes, including host defense, tissue repair, the pathogenesis of inflammatory disease and the progression of cancer. In contrast to its profound impact in vivo, IL-17 exhibits surprisingly moderate activity in cell-culture models, which presents a major knowledge gap about the molecular mechanisms of IL-17 signaling. Emerging studies are revealing a new dimension of complexity in the IL-17 pathway that may help explain its potent and diverse in vivo functions. Discoveries of new mRNA stabilizers and receptor-directed mRNA metabolism have provided insights into the means by which IL-17 cooperates functionally with other stimuli in driving inflammation, whether beneficial or destructive. The integration of IL-17 with growth-receptor signaling in specific cell types offers new understanding of the mitogenic effect of IL-17 on tissue repair and cancer. This Review summarizes new developments in IL-17 signaling and their pathophysiological implications.
Subject(s)
Immune System Diseases/immunology , Inflammation/immunology , Interleukin-17/metabolism , Neoplasms/immunology , Receptors, Interleukin-7/metabolism , Animals , Cells, Cultured , Humans , Signal TransductionABSTRACT
Mechanisms that degrade inflammatory mRNAs are well known; however, stabilizing mechanisms are poorly understood. Here, we show that Act1, an interleukin-17 (IL-17)-receptor-complex adaptor, binds and stabilizes mRNAs encoding key inflammatory proteins. The Act1 SEFIR domain binds a stem-loop structure, the SEFIR-binding element (SBE), in the 3' untranslated region (UTR) of Cxcl1 mRNA, encoding an inflammatory chemokine. mRNA-bound Act1 directs formation of three compartmentally distinct RNA-protein complexes (RNPs) that regulate three disparate events in inflammatory-mRNA metabolism: preventing mRNA decay in the nucleus, inhibiting mRNA decapping in P bodies and promoting translation. SBE RNA aptamers decreased IL-17-mediated mRNA stabilization in vitro, IL-17-induced skin inflammation and airway inflammation in a mouse asthma model, thus providing a therapeutic strategy for autoimmune diseases. These results reveal a network in which Act1 assembles RNPs on the 3' UTRs of select mRNAs and consequently controls receptor-mediated mRNA stabilization and translation during inflammation.
Subject(s)
Adaptor Proteins, Signal Transducing/metabolism , Inflammation/immunology , Interleukin-17/metabolism , RNA Stability/physiology , Signal Transduction/immunology , Adaptor Proteins, Signal Transducing/immunology , Animals , Gene Expression Regulation/immunology , Inflammation/metabolism , Interleukin-17/immunology , Mice , Mice, Inbred C57BL , RNA, Messenger/metabolism , Receptors, Interleukin-17/metabolismABSTRACT
Interleukin 1ß (IL-1ß) is critical for the in vivo survival, expansion and effector function of IL-17-producing helper T (T(H)17) cells during autoimmune responses, including experimental autoimmune encephalomyelitis (EAE). However, the spatiotemporal role and cellular source of IL-1ß during EAE pathogenesis are poorly defined. In the present study, we uncovered a T cell-intrinsic inflammasome that drives IL-1ß production during T(H)17-mediated EAE pathogenesis. Activation of T cell antigen receptors induced expression of pro-IL-1ß, whereas ATP stimulation triggered T cell production of IL-1ß via ASC-NLRP3-dependent caspase-8 activation. IL-1R was detected on T(H)17 cells but not on type 1 helper T (T(H)1) cells, and ATP-treated T(H)17 cells showed enhanced survival compared with ATP-treated T(H)1 cells, suggesting autocrine action of T(H)17-derived IL-1ß. Together these data reveal a critical role for IL-1ß produced by a T(H)17 cell-intrinsic ASC-NLRP3-caspase-8 inflammasome during inflammation of the central nervous system.
Subject(s)
Apoptosis Regulatory Proteins/immunology , Encephalomyelitis, Autoimmune, Experimental/immunology , T-Lymphocytes/immunology , Th17 Cells/immunology , Adenosine Triphosphate/pharmacology , Animals , Apoptosis Regulatory Proteins/genetics , Apoptosis Regulatory Proteins/metabolism , CARD Signaling Adaptor Proteins , CD4-Positive T-Lymphocytes/immunology , CD4-Positive T-Lymphocytes/metabolism , Carrier Proteins/genetics , Carrier Proteins/immunology , Carrier Proteins/metabolism , Caspase 8/genetics , Caspase 8/immunology , Caspase 8/metabolism , Cell Survival/genetics , Cell Survival/immunology , Cells, Cultured , Encephalomyelitis, Autoimmune, Experimental/genetics , Encephalomyelitis, Autoimmune, Experimental/metabolism , Flow Cytometry , Gene Expression/immunology , Immunoblotting , Inflammasomes/genetics , Inflammasomes/immunology , Inflammasomes/metabolism , Interleukin-17/genetics , Interleukin-17/immunology , Interleukin-17/metabolism , Interleukin-1beta/genetics , Interleukin-1beta/immunology , Interleukin-1beta/metabolism , Mice, Inbred C57BL , Mice, Knockout , Mice, Transgenic , NLR Family, Pyrin Domain-Containing 3 Protein , Reverse Transcriptase Polymerase Chain Reaction , Signal Transduction/genetics , Signal Transduction/immunology , T-Lymphocytes/drug effects , T-Lymphocytes/metabolism , Th17 Cells/drug effects , Th17 Cells/metabolismABSTRACT
IL-1ß can exit the cytosol as an exosomal cargo following inflammasome activation in intestinal epithelial cells (IECs) in a Gasdermin D (GSDMD)-dependent manner. The mechanistic connection linking inflammasome activation and the biogenesis of exosomes has so far remained largely elusive. Here, we report the Ras GTPase-activating-like protein IQGAP1 functions as an adaptor, bridging GSDMD to the endosomal sorting complexes required for transport (ESCRT) machinery to promote the biogenesis of pro-IL-1ß-containing exosomes in response to NLPR3 inflammasome activation. We identified IQGAP1 as a GSDMD-interacting protein through a non-biased proteomic analysis. Functional investigation indicated the IQGAP1-GSDMD interaction is required for LPS and ATP-induced exosome release. Further analysis revealed that IQGAP1 serves as an adaptor which bridges GSDMD and associated IL-1ß complex to Tsg101, a component of the ESCRT complex, and enables the packaging of GSDMD and IL-1ß into exosomes. Importantly, this process is dependent on an LPS-induced increase in GTP-bound CDC42, a small GTPase known to activate IQGAP1. Taken together, this study reveals IQGAP1 as a link between inflammasome activation and GSDMD-dependent, ESCRT-mediated exosomal release of IL-1ß.
Subject(s)
Exosomes , Inflammasomes , Inflammasomes/metabolism , Intracellular Signaling Peptides and Proteins/genetics , Intracellular Signaling Peptides and Proteins/metabolism , Gasdermins , Exosomes/metabolism , ras Proteins/metabolism , Lipopolysaccharides/pharmacology , Proteomics , Endosomal Sorting Complexes Required for Transport/genetics , Endosomal Sorting Complexes Required for Transport/metabolism , Interleukin-1beta/metabolism , PyroptosisABSTRACT
Fungal infection stimulates the canonical C-type lectin receptor (CLR) signaling pathway via activation of the tyrosine kinase Syk. Here we identify a crucial role for the tyrosine phosphatase SHP-2 in mediating CLR-induced activation of Syk. Ablation of the gene encoding SHP-2 (Ptpn11; called 'Shp-2' here) in dendritic cells (DCs) and macrophages impaired Syk-mediated signaling and abrogated the expression of genes encoding pro-inflammatory molecules following fungal stimulation. Mechanistically, SHP-2 operated as a scaffold, facilitating the recruitment of Syk to the CLR dectin-1 or the adaptor FcRγ, through its N-SH2 domain and a previously unrecognized carboxy-terminal immunoreceptor tyrosine-based activation motif (ITAM). We found that DC-derived SHP-2 was crucial for the induction of interleukin 1ß (IL-1ß), IL-6 and IL-23 and anti-fungal responses of the TH17 subset of helper T cells in controlling infection with Candida albicans. Together our data reveal a mechanism by which SHP-2 mediates the activation of Syk in response to fungal infection.
Subject(s)
Candidiasis/immunology , Dendritic Cells/physiology , Intracellular Signaling Peptides and Proteins/metabolism , Macrophages/physiology , Protein Tyrosine Phosphatase, Non-Receptor Type 11/metabolism , Protein-Tyrosine Kinases/metabolism , T-Lymphocytes, Helper-Inducer/immunology , Th17 Cells/immunology , Amino Acid Motifs/genetics , Animals , Antigens, Fungal/immunology , Cells, Cultured , Cytokines/metabolism , Enzyme Activation , Inflammation Mediators/metabolism , Lectins, C-Type/genetics , Lectins, C-Type/metabolism , Lymphocyte Activation , Membrane Proteins/genetics , Mice , Mice, Inbred C57BL , Mice, Knockout , Mutation/genetics , Protein Tyrosine Phosphatase, Non-Receptor Type 11/genetics , Receptors, IgE/genetics , Receptors, IgE/metabolism , Signal Transduction , Syk KinaseABSTRACT
Alternative splicing (AS) plays crucial roles in regulating various biological processes in plants. However, the genetic mechanisms underlying AS and its role in controlling important agronomic traits in rice (Oryza sativa) remain poorly understood. In this study, we explored AS in rice leaves and panicles using the rice minicore collection. Our analysis revealed a high level of transcript isoform diversity, with approximately one fifth of potential isoforms acting as major transcripts in both tissues. Regarding the genetic mechanism of AS, we found that the splicing of 833 genes in the leaf and 1,230 genes in the panicle was affected by cis-genetic variation. Twenty-one percent of these AS events could only be explained by large structural variations. Approximately 77.5% of genes with significant splicing quantitative trait loci (sGenes) exhibited tissue-specific regulation, and AS can cause 26.9% (leaf) and 23.6% (panicle) of sGenes to have altered, lost or gained functional domains. Additionally, through splicing-phenotype association analysis, we identified phosphate-starvation induced RING-type E3 ligase (OsPIE1; LOC_Os01g72480), whose splicing ratio was significantly associated with plant height. In summary, this study provides an understanding of AS in rice and its contribution to the regulation of important agronomic traits.
ABSTRACT
Multisite phosphorylation of kinases can induce on-off or graded regulation of catalytic activity; however, its influence on substrate specificity remains unclear. Here, we show that multisite phosphorylation of ribosomal protein S6 kinase 1 (S6K1) alters target selection. Agonist-inducible phosphorylation of glutamyl-prolyl tRNA synthetase (EPRS) by S6K1 in monocytes and adipocytes requires not only canonical phosphorylation at Thr389 by mTORC1 but also phosphorylation at Ser424 and Ser429 in the C terminus by cyclin-dependent kinase 5 (Cdk5). S6K1 phosphorylation at these additional sites induces a conformational switch and is essential for high-affinity binding and phosphorylation of EPRS, but not canonical S6K1 targets, e.g., ribosomal protein S6. Unbiased proteomic analysis identified additional targets phosphorylated by multisite phosphorylated S6K1 in insulin-stimulated adipocytes-namely, coenzyme A synthase, lipocalin 2, and cortactin. Thus, embedded within S6K1 is a target-selective kinase phospho-code that integrates signals from mTORC1 and Cdk5 to direct an insulin-stimulated, post-translational metabolon determining adipocyte lipid metabolism.
Subject(s)
Adipocytes/enzymology , Lipid Metabolism , Myeloid Cells/enzymology , Protein Processing, Post-Translational , Ribosomal Protein S6 Kinases, 70-kDa/metabolism , Ribosomal Protein S6 Kinases, 90-kDa/metabolism , 3T3-L1 Cells , Adipocytes/drug effects , Amino Acyl-tRNA Synthetases/metabolism , Animals , Cyclin-Dependent Kinase 5/metabolism , Enzyme Activation , HEK293 Cells , Hep G2 Cells , Humans , Insulin/pharmacology , Interferon-gamma/pharmacology , Lipid Metabolism/drug effects , Mechanistic Target of Rapamycin Complex 1/metabolism , Mice , Myeloid Cells/drug effects , Phosphorylation , Proteomics/methods , Ribosomal Protein S6 Kinases, 70-kDa/genetics , Ribosomal Protein S6 Kinases, 90-kDa/genetics , Signal Transduction , Substrate Specificity , U937 CellsABSTRACT
Here we identified a population of bone marrow neutrophils that constitutively expressed the transcription factor RORγt and produced and responded to interleukin 17A (IL-17A (IL-17)). IL-6, IL-23 and RORγt, but not T cells or natural killer (NK) cells, were required for IL-17 production in neutrophils. IL-6 and IL-23 induced expression of the receptors IL-17RC and dectin-2 on neutrophils, and IL-17RC expression was augmented by activation of dectin-2. Autocrine activity of IL-17A and its receptor induced the production of reactive oxygen species (ROS), and increased fungal killing in vitro and in a model of Aspergillus-induced keratitis. Human neutrophils also expressed RORγt and induced the expression of IL-17A, IL-17RC and dectin-2 following stimulation with IL-6 and IL-23. Our findings identify a population of human and mouse neutrophils with autocrine IL-17 activity that probably contribute to the etiology of microbial and inflammatory diseases.
Subject(s)
Aspergillosis/immunology , Aspergillus/immunology , Interleukin-17/metabolism , Keratitis/immunology , Neutrophils/immunology , Receptors, Interleukin/metabolism , Animals , Aspergillosis/complications , Autocrine Communication , Bone Marrow Cells/immunology , Cell Degranulation , Cells, Cultured , Cytotoxicity, Immunologic/genetics , Disease Models, Animal , Humans , Interleukin-17/genetics , Interleukin-17/immunology , Interleukin-23/immunology , Interleukin-6/immunology , Keratitis/etiology , Lectins, C-Type/genetics , Lectins, C-Type/metabolism , Mice , Mice, Inbred C57BL , Mice, Knockout , Nuclear Receptor Subfamily 1, Group F, Member 3/genetics , Nuclear Receptor Subfamily 1, Group F, Member 3/metabolism , Reactive Oxygen Species/metabolismABSTRACT
Granulocyte-macrophage colony-stimulating factor (GM-CSF or Csf-2) is a pro-inflammatory mediator implicated in the pathogenesis of various autoimmune diseases. In this issue of Immunity, Spath et al. (2017) show that the dysregulated production of GM-CSF rather than IL-17 induces spontaneous immunopathology in a mouse model of CNS inflammation.
Subject(s)
Granulocyte-Macrophage Colony-Stimulating Factor , Interleukin-17 , Animals , InflammationABSTRACT
In cancer cells, endogenous or therapy-induced DNA damage leads to the abnormal presence of DNA in the cytoplasm, which triggers the activation of cGAS (cyclic GMP-AMP synthase) and STING (stimulator of interferon genes). STAT2 suppresses the cGAMP-induced expression of IRF3-dependent genes by binding to STING, blocking its intracellular trafficking, which is essential for the full response to STING activation. STAT2 reshapes STING signaling by inhibiting the induction of IRF3-dependent, but not NF-κB-dependent genes. This noncanonical activity of STAT2 is regulated independently of its tyrosine phosphorylation but does depend on the phosphorylation of threonine 404, which promotes the formation of a STAT2:STING complex that keeps STING bound to the endoplasmic reticulum (ER) and increases resistance to DNA damage. We conclude that STAT2 is a key negative intracellular regulator of STING, a function that is quite distinct from its function as a transcription factor.
Subject(s)
Membrane Proteins , Nucleotidyltransferases , Protein Serine-Threonine Kinases , STAT2 Transcription Factor , DNA/metabolism , DNA Damage , Nucleotidyltransferases/metabolism , Phosphorylation , Protein Serine-Threonine Kinases/metabolism , Signal Transduction , STAT2 Transcription Factor/metabolism , Membrane Proteins/metabolismABSTRACT
Act1 is an essential adaptor in interleukin 17 (IL-17)-mediated signaling and is recruited to the receptor for IL-17 after stimulation with IL-17. Here we found that Act1 was a 'client' protein of the molecular chaperone hsp90. The D10N variant of Act1 (Act1(D10N)) that is linked to susceptibility to psoriasis was defective in its interaction with hsp90, which resulted in a global loss of Act1 function. Act1-deficient mice modeled the mechanistic link between loss of Act1 function and susceptibility to psoriasis. Although Act1 was necessary for IL-17-mediated inflammation, Act1-deficient mice had a hyperactive response of the T(H)17 subset of helper T cells and developed spontaneous IL-22-dependent skin inflammation. In the absence of IL-17 signaling, IL-22 was the main contributor to skin inflammation, which provides a molecular mechanism for the association of Act1(D10N) with psoriasis susceptibility.
Subject(s)
Connexin 43/metabolism , HSP90 Heat-Shock Proteins/metabolism , Molecular Chaperones/metabolism , Peptide Fragments/metabolism , Psoriasis/immunology , Th17 Cells/immunology , Animals , Cell Line , Connexin 43/genetics , Connexin 43/immunology , Disease Models, Animal , Genetic Predisposition to Disease , Humans , Interleukin-17/metabolism , Mice , Mice, Knockout , Molecular Chaperones/genetics , Mutation/genetics , Peptide Fragments/genetics , Peptide Fragments/immunology , Polymorphism, Genetic , Protein Binding/genetics , Protein Binding/immunology , Psoriasis/genetics , Signal TransductionABSTRACT
Polyploid hybrid rice (Oryza sativa) has great potential for increasing yields. However, hybrid rice depends on male fertility and its regulation, which is less well studied in polyploid rice than in diploid rice. We previously identified an MYB transcription factor, MORE FLORET1 (MOF1), whose mutation causes male sterility in neo-tetraploid rice. MOF1 expression in anthers peaks at anther Stage 7 (S7) and progressively decreases to low levels at S10. However, it remains unclear how the dynamics of MOF1 expression contribute to male fertility. Here, we carefully examined anther development in both diploid and tetraploid mof1 rice mutants, as well as lines ectopically expressing MOF1 in a temporal manner. MOF1 mutations caused delayed degeneration of the tapetum and middle layer of anthers and aberrant pollen wall organization. Ectopic MOF1 expression at later stages of anther development led to retarded cytoplasmic reorganization of tapetal cells. In both cases, pollen grains were aborted and seed production was abolished, indicating that precise control of MOF1 expression is essential for male reproduction. We demonstrated that 5 key tapetal genes, CYP703A3 (CYTOCHROME P450 HYDROXYLASE 703A3), OsABCG26 (O. sativa ATP BINDING CASSETTE G26), PTC1 (PERSISTENT TAPETAL CELL1), PKS2 (POLYKETIDE SYNTHASE 2), and OsABCG15 (O. sativa ATP BINDING CASSETTE G15), exhibit expression patterns opposite to those of MOF1 and are negatively regulated by MOF1. Moreover, DNA affinity purification sequencing (DAP-seq), luciferase activity assays, and electrophoretic mobility shift assays indicated that MOF1 binds directly to the PKS2 promoter for transcriptional repression. Our results provide a mechanistic basis for the regulation of male reproduction by MOF1 in both diploid and tetraploid rice. This study will facilitate the development of polyploid male sterile lines, which are useful for breeding of polyploid hybrid rice.
Subject(s)
Diploidy , Flowers , Gene Expression Regulation, Plant , Oryza , Plant Proteins , Pollen , Tetraploidy , Oryza/genetics , Oryza/growth & development , Plant Proteins/genetics , Plant Proteins/metabolism , Flowers/genetics , Flowers/growth & development , Pollen/genetics , Pollen/growth & development , Mutation/genetics , Genes, Plant , Transcription Factors/genetics , Transcription Factors/metabolismABSTRACT
Cellular senescence significantly affects the proliferative and differentiation capacities of mesenchymal stem cells (MSCs). Identifying key regulators of senescence and exploring potential intervention strategies, including drug-based approaches, are active areas of research. In this context, S-adenosyl-l-methionine (SAM), a critical intermediate in sulfur amino acid metabolism, emerges as a promising candidate for mitigating MSC senescence. In a hydrogen peroxide-induced MSC aging model (100 µM for 2 hours), SAM (50 and 100 µM) was revealed to alleviate the senescence of MSCs, and also attenuated the level of reactive oxygen species and enhanced the adipogenic and osteogenic differentiation in senescent MSCs. In a premature aging mouse model (subcutaneously injected with 150 mg/kg/day d-galactose in the neck and back for 7 weeks), SAM (30 mg/kg/day by gavage for 5 weeks) was shown to delay the overall aging process while increasing the number and thickness of bone trabeculae in the distal femur. Mechanistically, activation of PI3K/AKT signaling and increased phosphorylation of forkhead box O3 (FOXO3a) was proved to be associated with the antisenescence role of SAM. These findings highlight that the PI3K/AKT/FOXO3a axis in MSCs could play a crucial role in MSCs senescence and suggest that SAM may be a potential therapeutic drug for MSCs senescence and related diseases.
Subject(s)
Cellular Senescence , Forkhead Box Protein O3 , Mesenchymal Stem Cells , Phosphatidylinositol 3-Kinases , Proto-Oncogene Proteins c-akt , S-Adenosylmethionine , Signal Transduction , Mesenchymal Stem Cells/metabolism , Mesenchymal Stem Cells/drug effects , Mesenchymal Stem Cells/cytology , Animals , Cellular Senescence/drug effects , Forkhead Box Protein O3/metabolism , Forkhead Box Protein O3/genetics , Signal Transduction/drug effects , Proto-Oncogene Proteins c-akt/metabolism , Phosphatidylinositol 3-Kinases/metabolism , S-Adenosylmethionine/pharmacology , S-Adenosylmethionine/metabolism , Mice , Cell Differentiation/drug effects , Male , Humans , Mice, Inbred C57BLABSTRACT
Detailed knowledge of the genetic variations in diverse crop populations forms the basis for genetic crop improvement and gene functional studies. In the present study, we analyzed a large rice population with a total of 10 548 accessions to construct a rice super-population variation map (RSPVM), consisting of 54 378 986 single nucleotide polymorphisms, 11 119 947 insertion/deletion mutations and 184 736 presence/absence variations. Assessment of variation detection efficiency for different population sizes revealed a sharp increase of all types of variation as the population size increased and a gradual saturation of that after the population size reached 10 000. Variant frequency analysis indicated that â¼90% of the obtained variants were rare, and would therefore likely be difficult to detect in a relatively small population. Among the rare variants, only 2.7% were predicted to be deleterious. Population structure, genetic diversity and gene functional polymorphism of this large population were evaluated based on different subsets of RSPVM, demonstrating the great potential of RSPVM for use in downstream applications. Our study provides both a rich genetic basis for understanding natural rice variations and a powerful tool for exploiting great potential of rare variants in future rice research, including population genetics and functional genomics.
Subject(s)
Genetic Variation , Oryza , Genetics, Population , Genomics , Oryza/genetics , Polymorphism, Single NucleotideABSTRACT
Species interactions such as facilitation and competition play a crucial role in driving species range shifts. However, density dependence as a key feature of these processes has received little attention in both empirical and modelling studies. Herein, we used a novel, individual-based treeline model informed by rich in situ observations to quantify the contribution of density-dependent species interactions to alpine treeline dynamics, an iconic biome boundary recognized as an indicator of global warming. We found that competition and facilitation dominate in dense versus sparse vegetation scenarios respectively. The optimal balance between these two effects was identified at an intermediate vegetation thickness where the treeline elevation was the highest. Furthermore, treeline shift rates decreased sharply with vegetation thickness and the associated transition from positive to negative species interactions. We thus postulate that vegetation density must be considered when modelling species range dynamics to avoid inadequate predictions of its responses to climate warming.
Subject(s)
Ecosystem , Trees , Trees/physiology , Global Warming , Climate Change , ClimateABSTRACT
Impedance matching modulation of the electromagnetic wave (EMW) absorbers toward broad effective absorption bandwidth (EAB) is the ultimate aim in EMW attenuation applications. Here, a Joule heating strategy is reported for preparation of the Co-loaded carbon (Co/C) absorber with tunable impedance characteristics. Typically, the size of the Co can be regulated to range from single-atoms to clusters, and to nanocrystals. The varied sizes of the Co combined with different graphitization degrees of carbon can result in different relative input impedances and electromagnetic loss, leading to the tunable EMW absorption properties of the Co/C absorber. By meticulously coalescing the different prepared Co/C, the working frequency can be easily tuned, covering Ku, X, and C bands. Furthermore, the Co/C demonstrates a high EMW attenuation due to its unique dielectric loss capability and magnetic loss characteristics. The abundant interfaces of Co/C can also contribute to the enhanced interfacial polarization for improving EMW attenuation. This work demonstrates the importance of optimizing the metal and carbon interaction to the impedance matching toward wide EAB of the EMW absorbers.