ABSTRACT
Biliary atresia (BA) is a severe cholangiopathy that leads to liver failure in infants, but its pathogenesis remains to be fully characterized. By single-cell RNA profiling, we observed macrophage hypo-inflammation, Kupffer cell scavenger function defects, cytotoxic T cell expansion, and deficiency of CX3CR1+effector T and natural killer (NK) cells in infants with BA. More importantly, we discovered that hepatic B cell lymphopoiesis did not cease after birth and that tolerance defects contributed to immunoglobulin G (IgG)-autoantibody accumulation in BA. In a rhesus-rotavirus induced BA model, depleting B cells or blocking antigen presentation ameliorated liver damage. In a pilot clinical study, we demonstrated that rituximab was effective in depleting hepatic B cells and restoring the functions of macrophages, Kupffer cells, and T cells to levels comparable to those of control subjects. In summary, our comprehensive immune profiling in infants with BA had educed that B-cell-modifying therapies may alleviate liver pathology.
Subject(s)
Biliary Atresia/immunology , Biliary Atresia/therapy , Liver/immunology , Animals , Antigens, CD20/metabolism , B-Lymphocytes/immunology , Biliary Atresia/blood , Biliary Atresia/drug therapy , Biopsy , CX3C Chemokine Receptor 1/metabolism , Cell Death , Cell Line , Cell Proliferation , Cell Transdifferentiation , Child , Child, Preschool , Cohort Studies , Cytotoxicity, Immunologic , Disease Models, Animal , Female , Humans , Immunoglobulin G/metabolism , Infant , Inflammation/pathology , Killer Cells, Natural/immunology , Kupffer Cells/pathology , Liver/pathology , Liver Cirrhosis/blood , Liver Cirrhosis/complications , Liver Cirrhosis/immunology , Liver Cirrhosis/pathology , Lymphocyte Depletion , Lymphopoiesis , Male , Mice, Inbred BALB C , Phagocytosis , RNA/metabolism , Rituximab/administration & dosage , Rituximab/pharmacology , Rituximab/therapeutic use , Rotavirus/physiology , Single-Cell Analysis , Th1 Cells/immunology , Th17 Cells/immunologyABSTRACT
Checkpoint blockade enhances effector T cell function and has elicited long-term remission in a subset of patients with a broad spectrum of cancers. TIGIT is a checkpoint receptor thought to be involved in mediating T cell exhaustion in tumors; however, the relevance of TIGIT to the dysfunction of natural killer (NK) cells remains poorly understood. Here we found that TIGIT, but not the other checkpoint molecules CTLA-4 and PD-1, was associated with NK cell exhaustion in tumor-bearing mice and patients with colon cancer. Blockade of TIGIT prevented NK cell exhaustion and promoted NK cell-dependent tumor immunity in several tumor-bearing mouse models. Furthermore, blockade of TIGIT resulted in potent tumor-specific T cell immunity in an NK cell-dependent manner, enhanced therapy with antibody to the PD-1 ligand PD-L1 and sustained memory immunity in tumor re-challenge models. This work demonstrates that TIGIT constitutes a previously unappreciated checkpoint in NK cells and that targeting TIGIT alone or in combination with other checkpoint receptors is a promising anti-cancer therapeutic strategy.
Subject(s)
Killer Cells, Natural/immunology , Neoplasms, Experimental/immunology , Receptors, Immunologic/metabolism , Adaptive Immunity , Animals , Cell Line , Colonic Neoplasms/immunology , Humans , Immunologic Memory , Lymphocytes, Tumor-Infiltrating/immunology , Melanoma, Experimental/immunology , Mice, Inbred BALB C , Mice, Inbred C57BL , Mice, Inbred NOD , Mice, SCID , Neoplasms, Experimental/metabolism , Receptors, Immunologic/antagonists & inhibitors , Receptors, Immunologic/geneticsABSTRACT
CTCF and the associated cohesin complex play a central role in insulator function and higher-order chromatin organization of mammalian genomes. Recent studies identified a correlation between the orientation of CTCF-binding sites (CBSs) and chromatin loops. To test the functional significance of this observation, we combined CRISPR/Cas9-based genomic-DNA-fragment editing with chromosome-conformation-capture experiments to show that the location and relative orientations of CBSs determine the specificity of long-range chromatin looping in mammalian genomes, using protocadherin (Pcdh) and ß-globin as model genes. Inversion of CBS elements within the Pcdh enhancer reconfigures the topology of chromatin loops between the distal enhancer and target promoters and alters gene-expression patterns. Thus, although enhancers can function in an orientation-independent manner in reporter assays, in the native chromosome context, the orientation of at least some enhancers carrying CBSs can determine both the architecture of topological chromatin domains and enhancer/promoter specificity. These findings reveal how 3D chromosome architecture can be encoded by linear genome sequences.
Subject(s)
Chromosomes/metabolism , Genetic Techniques , Repressor Proteins/metabolism , Animals , Binding Sites , CCCTC-Binding Factor , Cadherins/genetics , Cell Cycle Proteins/metabolism , Chromosomal Proteins, Non-Histone/metabolism , Chromosomes/chemistry , Clustered Regularly Interspaced Short Palindromic Repeats , DNA/chemistry , Enhancer Elements, Genetic , Gene Expression , Genome, Human , Humans , K562 Cells , Mice , Promoter Regions, Genetic , beta-Globins/genetics , CohesinsABSTRACT
Enhancers generate bidirectional noncoding enhancer RNAs (eRNAs) that may regulate gene expression. At present, the eRNA function remains enigmatic. Here, we report a 5' capped antisense eRNA PEARL (Pcdh eRNA associated with R-loop formation) that is transcribed from the protocadherin (Pcdh) α HS5-1 enhancer region. Through loss- and gain-of-function experiments with CRISPR/Cas9 DNA fragment editing, CRISPRi, and CRISPRa, as well as locked nucleic acid strategies, in conjunction with ChIRP, MeDIP, DRIP, QHR-4C, and HiChIP experiments, we found that PEARL regulates Pcdhα gene expression by forming local RNA-DNA duplexes (R-loops) in situ within the HS5-1 enhancer region to promote long-distance chromatin interactions between distal enhancers and target promoters. In particular, increased levels of eRNA PEARL via perturbing transcription elongation factor SPT6 lead to strengthened local three-dimensional chromatin organization within the Pcdh superTAD. These findings have important implications regarding molecular mechanisms by which the HS5-1 enhancer regulates stochastic Pcdhα promoter choice in single cells in the brain.
Subject(s)
Enhancer Elements, Genetic , Protocadherins , Chromatin , Enhancer Elements, Genetic/genetics , Gene Expression Regulation , Promoter Regions, Genetic/genetics , RNA , Transcription, GeneticABSTRACT
The neocortex consists of a vast number of diverse neurons that form distinct layers and intricate circuits at the single-cell resolution to support complex brain functions1. Diverse cell-surface molecules are thought to be key for defining neuronal identity, and they mediate interneuronal interactions for structural and functional organization2-6. However, the precise mechanisms that control the fine neuronal organization of the neocortex remain largely unclear. Here, by integrating in-depth single-cell RNA-sequencing analysis, progenitor lineage labelling and mosaic functional analysis, we report that the diverse yet patterned expression of clustered protocadherins (cPCDHs)-the largest subgroup of the cadherin superfamily of cell-adhesion molecules7-regulates the precise spatial arrangement and synaptic connectivity of excitatory neurons in the mouse neocortex. The expression of cPcdh genes in individual neocortical excitatory neurons is diverse yet exhibits distinct composition patterns linked to their developmental origin and spatial positioning. A reduction in functional cPCDH expression causes a lateral clustering of clonally related excitatory neurons originating from the same neural progenitor and a significant increase in synaptic connectivity. By contrast, overexpression of a single cPCDH isoform leads to a lateral dispersion of clonally related excitatory neurons and a considerable decrease in synaptic connectivity. These results suggest that patterned cPCDH expression biases fine spatial and functional organization of individual neocortical excitatory neurons in the mammalian brain.
Subject(s)
Gene Expression Regulation , Neocortex , Protocadherins , Animals , Mice , Interneurons/metabolism , Neocortex/anatomy & histology , Neocortex/cytology , Neocortex/metabolism , Neurons/metabolism , Protocadherins/genetics , Protocadherins/metabolism , Synapses/metabolism , Synaptic TransmissionABSTRACT
TMPRSS2-ERG gene fusion occurs in approximately 50% of cases of prostate cancer (PCa), and the fusion product is a key driver of prostate oncogenesis. However, how to leverage cellular signaling to ablate TMPRSS2-ERG oncoprotein for PCa treatment remains elusive. Here, we demonstrate that DNA damage induces proteasomal degradation of wild-type ERG and TMPRSS2-ERG oncoprotein through ERG threonine-187 and tyrosine-190 phosphorylation mediated by GSK3ß and WEE1, respectively. The dual phosphorylation triggers ERG recognition and degradation by the E3 ubiquitin ligase FBW7 in a manner independent of a canonical degron. DNA damage-induced TMPRSS2-ERG degradation was abolished by cancer-associated PTEN deletion or GSK3ß inactivation. Blockade of DNA damage-induced TMPRSS2-ERG oncoprotein degradation causes chemotherapy-resistant growth of fusion-positive PCa cells in culture and in mice. Our findings uncover a previously unrecognized TMPRSS2-ERG protein destruction mechanism and demonstrate that intact PTEN and GSK3ß signaling are essential for effective targeting of ERG protein by genotoxic therapeutics in fusion-positive PCa.
Subject(s)
Cell Cycle Proteins/genetics , Glycogen Synthase Kinase 3 beta/genetics , Oncogene Proteins, Fusion/genetics , PTEN Phosphohydrolase/genetics , Prostatic Neoplasms/genetics , Protein-Tyrosine Kinases/genetics , Animals , Carcinogenesis/genetics , Cell Line, Tumor , DNA Damage/drug effects , Drug Resistance, Neoplasm/genetics , Drug Therapy , F-Box-WD Repeat-Containing Protein 7/genetics , Heterografts , Humans , Male , Mice , Prostatic Neoplasms/drug therapy , Prostatic Neoplasms/pathology , Proteolysis/drug effects , Signal Transduction/drug effectsABSTRACT
The ability of neurites of the same neuron to avoid each other (self-avoidance) is a conserved feature in both invertebrates and vertebrates. The key to self-avoidance is the generation of a unique subset of cell-surface proteins in individual neurons engaging in isoform-specific homophilic interactions that drive neurite repulsion rather than adhesion. Among these cell-surface proteins are fly Dscam1 and vertebrate clustered protocadherins (cPcdhs), as well as the recently characterized shortened Dscam (sDscam) in the Chelicerata. Herein, we review recent advances in our understanding of how cPcdh, Dscam, and sDscam cell-surface recognition codes are expressed and translated into cellular functions essential for neural wiring.
Subject(s)
Cell Adhesion Molecules , Drosophila Proteins , Protocadherins , Animals , Cell Adhesion Molecules/metabolism , Cell Communication , Drosophila Proteins/metabolism , Neurons/metabolism , Protein Isoforms/metabolism , Invertebrates , VertebratesABSTRACT
Aberrant expression of programmed death ligand-1 (PD-L1) in tumor cells promotes cancer progression by suppressing cancer immunity. The retinoblastoma protein RB is a tumor suppressor known to regulate the cell cycle, DNA damage response, and differentiation. Here, we demonstrate that RB interacts with nuclear factor κB (NF-κB) protein p65 and that their interaction is primarily dependent on CDK4/6-mediated serine-249/threonine-252 (S249/T252) phosphorylation of RB. RNA-seq analysis shows a subset of NF-κB pathway genes including PD-L1 are selectively upregulated by RB knockdown or CDK4/6 inhibitor. S249/T252-phosphorylated RB inversely correlates with PD-L1 expression in patient samples. Expression of a RB-derived S249/T252 phosphorylation-mimetic peptide suppresses radiotherapy-induced upregulation of PD-L1 and augments therapeutic efficacy of radiation in vivo. Our findings reveal a previously unrecognized tumor suppressor function of hyperphosphorylated RB in suppressing NF-κB activity and PD-L1 expression and suggest that the RB-NF-κB axis can be exploited to overcome cancer immune evasion triggered by conventional or targeted therapies.
Subject(s)
B7-H1 Antigen/metabolism , Prostatic Neoplasms/metabolism , Retinoblastoma Protein/metabolism , Transcription Factor RelA/metabolism , Tumor Escape , Animals , Antineoplastic Agents, Immunological/pharmacology , B7-H1 Antigen/antagonists & inhibitors , B7-H1 Antigen/genetics , B7-H1 Antigen/immunology , Chemoradiotherapy/methods , Cyclin-Dependent Kinase 4/metabolism , Cyclin-Dependent Kinase 6/metabolism , Gene Expression Regulation, Neoplastic , HEK293 Cells , Humans , Male , Mice, Inbred C57BL , Mice, Inbred NOD , Mice, Knockout , Mice, SCID , PC-3 Cells , Phosphorylation , Prostatic Neoplasms/genetics , Prostatic Neoplasms/immunology , Prostatic Neoplasms/therapy , Protein Binding , Protein Interaction Domains and Motifs , Radiation Tolerance , Retinoblastoma Protein/genetics , Retinoblastoma Protein/immunology , Signal Transduction , Transcription Factor RelA/genetics , Transcription Factor RelA/immunology , Xenograft Model Antitumor AssaysABSTRACT
Chromosomal rearrangements including large DNA-fragment inversions, deletions, and duplications by Cas9 with paired sgRNAs are important to investigate genome structural variations and developmental gene regulation, but little is known about the underlying mechanisms. Here, we report that disrupting CtIP or FANCD2, which have roles in alternative non-homologous end joining, enhances precise DNA-fragment deletion. By analyzing the inserted nucleotides at the junctions of DNA-fragment editing of deletions, inversions, and duplications and characterizing the cleaved products, we find that Cas9 endonucleolytically cleaves the noncomplementary strand with a flexible scissile profile upstream of the -3 position of the PAM site in vivo and in vitro, generating double-strand break ends with 5' overhangs of 1-3 nucleotides. Moreover, we find that engineered Cas9 nucleases have distinct cleavage profiles. Finally, Cas9-mediated nucleotide insertions are nonrandom and are equal to the combined sequences upstream of both PAM sites with predicted frequencies. Thus, precise and predictable DNA-fragment editing could be achieved by perturbing DNA repair genes and using appropriate PAM configurations.
Subject(s)
CRISPR-Associated Protein 9/genetics , CRISPR-Cas Systems , Clustered Regularly Interspaced Short Palindromic Repeats , DNA End-Joining Repair , Gene Editing/methods , RNA, Guide, Kinetoplastida/genetics , Base Sequence , CRISPR-Associated Protein 9/metabolism , Carrier Proteins/genetics , Carrier Proteins/metabolism , DNA/genetics , DNA/metabolism , DNA Breaks, Double-Stranded , Endodeoxyribonucleases , Fanconi Anemia Complementation Group D2 Protein/genetics , Fanconi Anemia Complementation Group D2 Protein/metabolism , Gene Duplication , Genome, Human , HEK293 Cells , Humans , Mutagenesis, Insertional , Nuclear Proteins/genetics , Nuclear Proteins/metabolism , RNA, Guide, Kinetoplastida/metabolism , Sequence Deletion , Sequence InversionABSTRACT
It is now well known that solids under ultra-high-pressure shock compression will enter the warm dense matter (WDM) regime which connects condensed matter and hot plasma. How condensed matter turns into the WDM, however, remains largely unexplored due to the lack of data in the transition pressure range. In this letter, by employing the unique high-Z three-stage gas gun launcher technique developed recently, we compress gold into TPa shock pressure to fill the gap inaccessible by the two-stage gas gun and laser shock experiments. With the aid of high-precision Hugoniot data obtained experimentally, we observe a clear softening behavior beyond ~560 GPa. The state-of-the-art ab-initio molecular dynamics calculations reveal that the softening is caused by the ionization of 5d electrons in gold. This work quantifies the partial ionization effect of electrons under extreme conditions, which is critical to model the transition region between condensed matter and WDM.
ABSTRACT
Earth's inner core is predominantly composed of solid iron (Fe) and displays intriguing properties such as strong shear softening and an ultrahigh Poisson's ratio. Insofar, physical mechanisms to explain these features coherently remain highly debated. Here, we have studied longitudinal and shear wave velocities of hcp-Fe (hexagonal close-packed iron) at relevant pressure-temperature conditions of the inner core using in situ shock experiments and machine learning molecular dynamics (MLMD) simulations. Our results demonstrate that the shear wave velocity of hcp-Fe along the Hugoniot in the premelting condition, defined as T/Tm (Tm: melting temperature of iron) above 0.96, is significantly reduced by ~30%, while Poisson's ratio jumps to approximately 0.44. MLMD simulations at 230 to 330 GPa indicate that collective motion with fast diffusive atomic migration occurs in premelting hcp-Fe primarily along [100] or [010] crystallographic direction, contributing to its elastic softening and enhanced Poisson's ratio. Our study reveals that hcp-Fe atoms can diffusively migrate to neighboring positions, forming open-loop and close-loop clusters in the inner core conditions. Hcp-Fe with collective motion at the inner core conditions is thus not an ideal solid previously believed. The premelting hcp-Fe with collective motion behaves like an extremely soft solid with an ultralow shear modulus and an ultrahigh Poisson's ratio that are consistent with seismic observations of the region. Our findings indicate that premelting hcp-Fe with fast diffusive motion represents the underlying physical mechanism to help explain the unique seismic and geodynamic features of the inner core.
ABSTRACT
Mesothelial cells with reactive hyperplasia are difficult to distinguish from malignant mesothelioma cells based on cell morphology. This study aimed to identify and validate potential biomarkers that distinguish mesothelial cells from mesothelioma cells through machine learning combined with immunohistochemistry. It integrated the gene expression matrix from three Gene Expression Omnibus data sets (GSE2549, GSE12345, and GSE51024) to analyze the differently expressed genes between normal and mesothelioma tissues. Then, three machine learning algorithms, least absolute shrinkage and selection operator, support vector machine recursive feature elimination, and random forest were used to screen and obtain four shared candidate markers, including ACADL, EMP2, GPD1L, and HMMR. The receiver operating characteristic curve analysis showed that the area under the curve for distinguishing normal mesothelial cells from mesothelioma was 0.976, 0.943, 0.962, and 0.956, respectively. The expression and diagnostic performance of these candidate genes were validated in two additional independent data sets (GSE42977 and GSE112154), indicating that the performances of ACADL, GPD1L, and HMMR were consistent between the training and validation data sets. Finally, the optimal candidate marker ACADL was verified by immunohistochemistry assay. Acyl-CoA dehydrogenase long chain (ACADL) was stained strongly in mesothelial cells, especially for reactive hyperplasic mesothelial cells, but was negative in malignant mesothelioma cells. Therefore, ACADL has the potential to be used as a specific marker of reactive hyperplasic mesothelial cells in the differential diagnosis of mesothelioma.
Subject(s)
Biomarkers, Tumor , Computational Biology , Machine Learning , Mesothelioma, Malignant , Mesothelioma , Humans , Biomarkers, Tumor/genetics , Biomarkers, Tumor/metabolism , Mesothelioma/genetics , Mesothelioma/pathology , Mesothelioma/diagnosis , Mesothelioma/metabolism , Computational Biology/methods , Mesothelioma, Malignant/genetics , Mesothelioma, Malignant/pathology , Mesothelioma, Malignant/metabolism , Mesothelioma, Malignant/diagnosis , Lung Neoplasms/genetics , Lung Neoplasms/pathology , Lung Neoplasms/metabolism , Lung Neoplasms/diagnosis , Epithelium/metabolism , Epithelium/pathologyABSTRACT
Platelet hyperactivity represents a deleterious physiological phenomenon in diabetes mellitus (DM). This study aimed to explore the role of FUN14 domain containing 1 (FUNDC1) in platelet activation within the context of DM and to uncover relevant mechanisms, with a focus on mitophagy. A mouse model of DM was established by high-fat feeding and streptozotocin injection. Platelets isolated from whole blood were exposed to carbonyl cyanide-4-(trifluo-romethoxy)phenylhydrazone (FCCP) to induce mitophagy. The relative mRNA expression of FUNDC1 was detected by quantitative real-time PCR (qRT-PCR). Western blotting was employed to measure the protein levels of FUNDC1, the ratio of LC3-II toLC3-I, and cleaved caspase-3. Immunofluorescence and flow cytometry were performed to assess LC3-positive mitochondria and platelet activation factor CD62P, respectively. Additionally, serum levels of ß-thrombo-globulin (ß-TG) and platelet factor 4 (PF4)were measured by enzyme-linked immunosorbent assay. FUNDC1 expression was elevated in DM mice, and its silencing decreased the body weight and fasting blood glucose. Inhibition of FUNDC1 also significantly attenuated FCCP-induced platelet mitophagy, as evidenced by the down-regulation of the LC3-II/LC3-I ratio, up-regulation of Tomm20, and diminished presence of LC3-positive mitochondria. Moreover, platelet activation was noted in DM mice; this activation was mitigated upon FUNDC1 silencing, which was confirmed by the down-regulation of cleaved caspase-3 and CD62P as well as reductions in ß-TG and PF4 serum levels. Silencing of FUNDC1 inhibited platelet hyperactivity in DM by impeding mitophagy. As such, FUNDC1-midiated mitophagy may be a promising target for the treatment of DM and its associated cardiovascular complications related cardiovascular events.
Subject(s)
Diabetes Mellitus , Membrane Proteins , Mitochondrial Proteins , Mitophagy , Animals , Mice , Carbonyl Cyanide p-Trifluoromethoxyphenylhydrazone , Caspase 3 , Membrane Proteins/genetics , Membrane Proteins/metabolism , Mitochondrial Proteins/genetics , Mitochondrial Proteins/metabolism , Mitophagy/physiology , Platelet ActivationABSTRACT
Bromodomain-containing protein 9 (BRD9) is a specific subunit of the non-canonical SWI/SNF (ncBAF) chromatin-remodeling complex, whose function in human embryonic stem cells (hESCs) remains unclear. Here, we demonstrate that impaired BRD9 function reduces the self-renewal capacity of hESCs and alters their differentiation potential. Specifically, BRD9 depletion inhibits meso-endoderm differentiation while promoting neural ectoderm differentiation. Notably, supplementation of NODAL, TGF-ß, Activin A or WNT3A rescues the differentiation defects caused by BRD9 loss. Mechanistically, BRD9 forms a complex with BRD4, SMAD2/3, ß-CATENIN and P300, which regulates the expression of pluripotency genes and the activity of TGF-ß/Nodal/Activin and Wnt signaling pathways. This is achieved by regulating the deposition of H3K27ac on associated genes, thus maintaining and directing hESC differentiation. BRD9-mediated regulation of the TGF-ß/Activin/Nodal pathway is also demonstrated in the development of pancreatic and breast cancer cells. In summary, our study highlights the crucial role of BRD9 in the regulation of hESC self-renewal and differentiation, as well as its participation in the progression of pancreatic and breast cancers.
Subject(s)
Human Embryonic Stem Cells , Neoplasms , Humans , Transforming Growth Factor beta/genetics , Human Embryonic Stem Cells/metabolism , Nuclear Proteins/genetics , Nuclear Proteins/metabolism , Embryonic Stem Cells/metabolism , Transcription Factors/genetics , Transcription Factors/metabolism , Cell Differentiation/genetics , Activins/metabolism , Wnt Signaling Pathway , Neoplasms/metabolism , Cell Cycle Proteins/genetics , Cell Cycle Proteins/metabolismABSTRACT
Electrocatalytic CO2 reduction (CO2RR) to alcohols offers a promising strategy for converting waste CO2 into valuable fuels/chemicals but usually requires large overpotentials. Herein, we report a catalyst comprising unique oxygen-bridged Cu binuclear sites (CuOCu-N4) with a Cu···Cu distance of 3.0-3.1 Å and concomitant conventional Cu-N4 mononuclear sites on hierarchical nitrogen-doped carbon nanocages (hNCNCs). The catalyst exhibits a state-of-the-art low overpotential of 0.19 V (versus reversible hydrogen electrode) for ethanol and an outstanding ethanol Faradaic efficiency of 56.3% at an ultralow potential of -0.30 V, with high-stable Cu active-site structures during the CO2RR as confirmed by operando X-ray adsorption fine structure characterization. Theoretical simulations reveal that CuOCu-N4 binuclear sites greatly enhance the C-C coupling at low potentials, while Cu-N4 mononuclear sites and the hNCNC support increase the local CO concentration and ethanol production on CuOCu-N4. This study provides a convenient approach to advanced Cu binuclear site catalysts for CO2RR to ethanol with a deep understanding of the mechanism.
ABSTRACT
1D compound semiconductor nanomaterials possess unique physicochemical properties that strongly depend on their size, composition, and structures. ZnS has been widely investigated as one of the most important semiconductors, and the control of crystallographic orientation of 1D ZnS nanostructures is still challenging and crucial to exploring their anisotropic properties. Herein, a solution-processed strategy is developed to synthesize 1D wurtzite (w-)ZnS nanostructures with the specific <002> and <210> orientations by co-decomposing the copper dibutyldithiocarbamate {[(C4 H9 )2 NCS2 ]2 Cu, i.e., R2 Cu} and zinc dibutyldithiocarbamate (R2 Zn) precursors in the mixed solvents of oleylamine and 1-dodecanethoil. A solution-solid-solid (SSS)-Oriented growth mechanism is proposed, which includes oriented nucleation dominated and SSS growth dominated stages. The crystallographic orientation mainly depends on the interfacial energy and ligand effect. The 1D w-ZnS nanostructures with controlled crystallographic orientation display unique morphologies, i.e., <002>-oriented w-ZnS nanorod enclosed with {110} facets while <210>-oriented w-ZnS nanobelt enclosed with wide (002) and narrow (110) facets. The bandgap of 1D w-ZnS nanostructures can be tuned from 3.94 to 3.82 eV with the crystallographic growth direction varied from <002> to <210>, thus leading to the tunable band-edge emission from ≈338 to ≈345 nm.
ABSTRACT
Precious-metal single-atom catalysts (SACs), featured by high metal utilization and unique coordination structure for catalysis, demonstrate distinctive performances in the fields of heterogeneous and electrochemical catalysis. Herein, gold SACs are constructed on hierarchical nitrogen-doped carbon nanocages (hNCNC) via a simple impregnation-drying process and first exploited for electrocatalytic carbon dioxide reduction reaction (CO2RR) to produce syngas. The as-constructed Au SAC exhibits the high mass activity of 3319 A g-1 Au at -1.0 V (vs reversible hydrogen electrode, RHE), much superior to the Au nanoparticles supported on hNCNC. The ratio of H2/CO can be conveniently regulated in the range of 0.4-2.2 by changing the applied potential. Theoretical study indicates such a potential-dependent H2/CO ratio is attributed to the different responses of HER and CO2RR on Au single-atom sites coordinating with one N atom at the edges of micropores across the nanocage shells. The catalytic mechanism of the Au active sites is associated with the smooth switch between twofold and fourfold coordination during CO2RR, which much decreases the free energy changes of the rate-determining steps and promotes the reaction activity.
ABSTRACT
BACKGROUND: Inadequate nerve regeneration and an inhibitory local microenvironment are major obstacles to the repair of spinal cord injury (SCI). The activation and differentiation fate regulation of endogenous neural stem cells (NSCs) represent one of the most promising repair approaches. Metformin has been extensively studied for its antioxidative, anti-inflammatory, anti-aging, and autophagy-regulating properties in central nervous system diseases. However, the effects of metformin on endogenous NSCs remains to be elucidated. METHODS: The proliferation and differentiation abilities of NSCs were evaluated using CCK-8 assay, EdU/Ki67 staining and immunofluorescence staining. Changes in the expression of key proteins related to ferroptosis in NSCs were detected using Western Blot and immunofluorescence staining. The levels of reactive oxygen species, glutathione and tissue iron were measured using corresponding assay kits. Changes in mitochondrial morphology and membrane potential were observed using transmission electron microscopy and JC-1 fluorescence probe. Locomotor function recovery after SCI in rats was assessed through BBB score, LSS score, CatWalk gait analysis, and electrophysiological testing. The expression of the AMPK pathway was examined using Western Blot. RESULTS: Metformin promoted the proliferation and neuronal differentiation of NSCs both in vitro and in vivo. Furthermore, a ferroptosis model of NSCs using erastin treatment was established in vitro, and metformin treatment could reverse the changes in the expression of key ferroptosis-related proteins, increase glutathione synthesis, reduce reactive oxygen species production and improve mitochondrial membrane potential and morphology. Moreover, metformin administration improved locomotor function recovery and histological outcomes following SCI in rats. Notably, all the above beneficial effects of metformin were completely abolished upon addition of compound C, a specific inhibitor of AMP-activated protein kinase (AMPK). CONCLUSION: Metformin, driven by canonical AMPK-dependent regulation, promotes proliferation and neuronal differentiation of endogenous NSCs while inhibiting ferroptosis, thereby facilitating recovery of locomotor function following SCI. Our study further elucidates the protective mechanism of metformin in SCI, providing new mechanistic insights for its candidacy as a therapeutic agent for SCI.
Subject(s)
AMP-Activated Protein Kinases , Cell Differentiation , Cell Proliferation , Ferroptosis , Metformin , Neural Stem Cells , Rats, Sprague-Dawley , Spinal Cord Injuries , Metformin/pharmacology , Spinal Cord Injuries/drug therapy , Spinal Cord Injuries/pathology , Spinal Cord Injuries/metabolism , Animals , Neural Stem Cells/drug effects , Neural Stem Cells/metabolism , Cell Proliferation/drug effects , Cell Differentiation/drug effects , Ferroptosis/drug effects , AMP-Activated Protein Kinases/metabolism , Neurons/drug effects , Neurons/metabolism , Signal Transduction/drug effects , Rats , Reactive Oxygen Species/metabolism , Recovery of Function/drug effectsABSTRACT
Gene expression is regulated at multiple levels, including RNA processing and DNA methylation/demethylation. How these regulations are controlled remains unclear. Here, through analysis of a suppressor for the OsEIN2 over-expressor, we identified an RNA recognition motif protein SUPPRESSOR OF EIN2 (SOE). SOE is localized in nuclear speckles and interacts with several components of the spliceosome. We find SOE associates with hundreds of targets and directly binds to a DNA glycosylase gene DNG701 pre-mRNA for efficient splicing and stabilization, allowing for subsequent DNG701-mediated DNA demethylation of the transgene promoter for proper gene expression. The V81M substitution in the suppressor mutant protein mSOE impaired its protein stability and binding activity to DNG701 pre-mRNA, leading to transgene silencing. SOE mutation enhances grain size and yield. Haplotype analysis in c. 3000 rice accessions reveals that the haplotype 1 (Hap 1) promoter is associated with high 1000-grain weight, and most of the japonica accessions, but not indica ones, have the Hap 1 elite allele. Our study discovers a novel mechanism for the regulation of gene expression and provides an elite allele for the promotion of yield potentials in rice.
Subject(s)
Gene Expression Regulation, Plant , Gene Silencing , Oryza , Plant Proteins , Transgenes , Oryza/genetics , Plant Proteins/genetics , Plant Proteins/metabolism , Promoter Regions, Genetic/genetics , Mutation/genetics , Protein Domains , Haplotypes/genetics , DNA Methylation/genetics , Protein Binding , Plants, Genetically Modified , AllelesABSTRACT
PURPOSE: This study was designed to assess the advantages of radical antegrade modular pancreatosplenectomy (RAMPS) over standard retrograde pancreatosplenectomy (SPRS) in terms of disease-free survival (DFS) by comparing clinical outcomes. METHODS: Clinical data from 154 patients who underwent distal pancreatectomy at Tianjin Medical University Cancer Institute and Hospital between January 2015 and August 2018 were collected. We compared the preoperative conditions, postoperative complications, and survival outcomes of patients who underwent two different surgical procedures. By creating a LASSO-Cox model, we determined the parameters affecting DFS and the risk ratios of the two surgical procedures on DFS. RESULTS: The R0 resection rate (85.23% vs. 68.18%, P = 0.003), negative posterior margin rate (96.59% vs. 75.76%, P < 0.001), and tumor bed recurrence rate (15.29% vs. 40.00%, P = 0.001) significantly differed between the RAMPS and SPRS groups. The 1-, 3-, and 5-year survival and DFS rates of the RAMPS group were significantly better than those of the SPRS group (P < 0.05). Disease-free survival analysis based on Kaplan-Meier curves revealed that RAMPS was superior to SPRS (P < 0.001). CONCLUSIONS: We recommend RAMPS as the preferred procedure for treating ductal adenocarcinoma of the pancreatic body and tail due to its enhanced lymph node repair capacity and visualization of posterior pancreatic sections, which can increase DFS in patients.