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1.
Cell ; 175(6): 1546-1560.e17, 2018 11 29.
Artigo em Inglês | MEDLINE | ID: mdl-30500537

RESUMO

Mammalian folate metabolism is comprised of cytosolic and mitochondrial pathways with nearly identical core reactions, yet the functional advantages of such an organization are not well understood. Using genome-editing and biochemical approaches, we find that ablating folate metabolism in the mitochondria of mammalian cell lines results in folate degradation in the cytosol. Mechanistically, we show that QDPR, an enzyme in tetrahydrobiopterin metabolism, moonlights to repair oxidative damage to tetrahydrofolate (THF). This repair capacity is overwhelmed when cytosolic THF hyperaccumulates in the absence of mitochondrially produced formate, leading to THF degradation. Unexpectedly, we also find that the classic antifolate methotrexate, by inhibiting its well-known target DHFR, causes even more extensive folate degradation in nearly all tested cancer cell lines. These findings shed light on design features of folate metabolism, provide a biochemical basis for clinically observed folate deficiency in QDPR-deficient patients, and reveal a hitherto unknown and unexplored cellular effect of methotrexate.


Assuntos
Carbono/metabolismo , Citosol/metabolismo , Formiatos/metabolismo , Mitocôndrias/metabolismo , Neoplasias/metabolismo , Tetra-Hidrofolatos/metabolismo , Citosol/patologia , Células HCT116 , Células HeLa , Humanos , Células MCF-7 , Metotrexato/farmacocinética , Metotrexato/farmacologia , Mitocôndrias/patologia , Proteínas Mitocondriais/metabolismo , Proteínas de Neoplasias/metabolismo , Neoplasias/tratamento farmacológico , Neoplasias/patologia , Tetra-Hidrofolato Desidrogenase/metabolismo
2.
Mol Cell ; 84(13): 2472-2489.e8, 2024 Jul 11.
Artigo em Inglês | MEDLINE | ID: mdl-38996458

RESUMO

Pseudouridine (Ψ), the isomer of uridine, is ubiquitously found in RNA, including tRNA, rRNA, and mRNA. Human pseudouridine synthase 3 (PUS3) catalyzes pseudouridylation of position 38/39 in tRNAs. However, the molecular mechanisms by which it recognizes its RNA targets and achieves site specificity remain elusive. Here, we determine single-particle cryo-EM structures of PUS3 in its apo form and bound to three tRNAs, showing how the symmetric PUS3 homodimer recognizes tRNAs and positions the target uridine next to its active site. Structure-guided and patient-derived mutations validate our structural findings in complementary biochemical assays. Furthermore, we deleted PUS1 and PUS3 in HEK293 cells and mapped transcriptome-wide Ψ sites by Pseudo-seq. Although PUS1-dependent sites were detectable in tRNA and mRNA, we found no evidence that human PUS3 modifies mRNAs. Our work provides the molecular basis for PUS3-mediated tRNA modification in humans and explains how its tRNA modification activity is linked to intellectual disabilities.


Assuntos
Microscopia Crioeletrônica , Hidroliases , Transferases Intramoleculares , Pseudouridina , RNA de Transferência , Humanos , Domínio Catalítico , Células HEK293 , Hidroliases/metabolismo , Hidroliases/genética , Hidroliases/química , Deficiência Intelectual/genética , Deficiência Intelectual/metabolismo , Deficiência Intelectual/enzimologia , Modelos Moleculares , Mutação , Ligação Proteica , Pseudouridina/metabolismo , Pseudouridina/genética , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , RNA de Transferência/metabolismo , RNA de Transferência/genética , Especificidade por Substrato
3.
Nature ; 629(8014): 1174-1181, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38720073

RESUMO

Phosphorylation of proteins on tyrosine (Tyr) residues evolved in metazoan organisms as a mechanism of coordinating tissue growth1. Multicellular eukaryotes typically have more than 50 distinct protein Tyr kinases that catalyse the phosphorylation of thousands of Tyr residues throughout the proteome1-3. How a given Tyr kinase can phosphorylate a specific subset of proteins at unique Tyr sites is only partially understood4-7. Here we used combinatorial peptide arrays to profile the substrate sequence specificity of all human Tyr kinases. Globally, the Tyr kinases demonstrate considerable diversity in optimal patterns of residues surrounding the site of phosphorylation, revealing the functional organization of the human Tyr kinome by substrate motif preference. Using this information, Tyr kinases that are most compatible with phosphorylating any Tyr site can be identified. Analysis of mass spectrometry phosphoproteomic datasets using this compendium of kinase specificities accurately identifies specific Tyr kinases that are dysregulated in cells after stimulation with growth factors, treatment with anti-cancer drugs or expression of oncogenic variants. Furthermore, the topology of known Tyr signalling networks naturally emerged from a comparison of the sequence specificities of the Tyr kinases and the SH2 phosphotyrosine (pTyr)-binding domains. Finally we show that the intrinsic substrate specificity of Tyr kinases has remained fundamentally unchanged from worms to humans, suggesting that the fidelity between Tyr kinases and their protein substrate sequences has been maintained across hundreds of millions of years of evolution.


Assuntos
Fosfotirosina , Proteínas Tirosina Quinases , Especificidade por Substrato , Tirosina , Animais , Humanos , Motivos de Aminoácidos , Evolução Molecular , Espectrometria de Massas , Fosfoproteínas/química , Fosfoproteínas/metabolismo , Fosforilação , Fosfotirosina/metabolismo , Proteínas Tirosina Quinases/efeitos dos fármacos , Proteínas Tirosina Quinases/metabolismo , Proteoma/química , Proteoma/metabolismo , Proteômica , Transdução de Sinais , Domínios de Homologia de src , Tirosina/metabolismo , Tirosina/química
4.
Nature ; 613(7945): 759-766, 2023 01.
Artigo em Inglês | MEDLINE | ID: mdl-36631611

RESUMO

Protein phosphorylation is one of the most widespread post-translational modifications in biology1,2. With advances in mass-spectrometry-based phosphoproteomics, 90,000 sites of serine and threonine phosphorylation have so far been identified, and several thousand have been associated with human diseases and biological processes3,4. For the vast majority of phosphorylation events, it is not yet known which of the more than 300 protein serine/threonine (Ser/Thr) kinases encoded in the human genome are responsible3. Here we used synthetic peptide libraries to profile the substrate sequence specificity of 303 Ser/Thr kinases, comprising more than 84% of those predicted to be active in humans. Viewed in its entirety, the substrate specificity of the kinome was substantially more diverse than expected and was driven extensively by negative selectivity. We used our kinome-wide dataset to computationally annotate and identify the kinases capable of phosphorylating every reported phosphorylation site in the human Ser/Thr phosphoproteome. For the small minority of phosphosites for which the putative protein kinases involved have been previously reported, our predictions were in excellent agreement. When this approach was applied to examine the signalling response of tissues and cell lines to hormones, growth factors, targeted inhibitors and environmental or genetic perturbations, it revealed unexpected insights into pathway complexity and compensation. Overall, these studies reveal the intrinsic substrate specificity of the human Ser/Thr kinome, illuminate cellular signalling responses and provide a resource to link phosphorylation events to biological pathways.


Assuntos
Fosfoproteínas , Proteínas Serina-Treonina Quinases , Proteoma , Serina , Treonina , Humanos , Fosforilação , Proteínas Serina-Treonina Quinases/metabolismo , Serina/metabolismo , Especificidade por Substrato , Treonina/metabolismo , Proteoma/química , Proteoma/metabolismo , Conjuntos de Dados como Assunto , Fosfoproteínas/química , Fosfoproteínas/metabolismo , Linhagem Celular , Fosfosserina/metabolismo , Fosfotreonina/metabolismo
5.
Proc Natl Acad Sci U S A ; 121(40): e2404243121, 2024 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-39331410

RESUMO

Gprotein-coupled receptors (GPCRs) regulate several physiological and pathological processes and represent the target of approximately 30% of Food and Drug Administration-approved drugs. GPCR-mediated signaling was thought to occur exclusively at the plasma membrane. However, recent studies have unveiled their presence and function at subcellular membrane compartments. There is a growing interest in studying compartmentalized signaling of GPCRs. This requires development of tools to separate GPCR signaling at the plasma membrane from the ones initiated at intracellular compartments. We leveraged the structural and pharmacological information available for ß-adrenergic receptors (ßARs) and focused on ß1AR as exemplary GPCR that functions at subcellular compartments, and rationally designed spatially restricted antagonists. We generated a cell-impermeable ßAR antagonist by conjugating a suitable pharmacophore to a sulfonate-containing fluorophore. This cell-impermeable antagonist only inhibited ß1AR on the plasma membrane. In contrast, a cell-permeable ßAR antagonist containing a nonsulfonated fluorophore efficiently inhibited both the plasma membrane and Golgi pools of ß1ARs. Furthermore, the cell-impermeable antagonist selectively inhibited the phosphorylation of PKA downstream effectors near the plasma membrane, which regulate sarcoplasmic reticulum (SR) Ca2+ release in adult cardiomyocytes, while the ß1AR Golgi pool remained active. Our tools offer promising avenues for investigating compartmentalized ßAR signaling in various contexts, potentially advancing our understanding of ßAR-mediated cellular responses in health and disease. They also offer a general strategy to study compartmentalized signaling for other GPCRs in various biological systems.


Assuntos
Membrana Celular , Receptores Adrenérgicos beta 1 , Humanos , Animais , Membrana Celular/metabolismo , Membrana Celular/efeitos dos fármacos , Receptores Adrenérgicos beta 1/metabolismo , Transdução de Sinais/efeitos dos fármacos , Miócitos Cardíacos/metabolismo , Miócitos Cardíacos/efeitos dos fármacos , Células HEK293 , Antagonistas Adrenérgicos beta/farmacologia , Receptores Adrenérgicos beta/metabolismo , Cálcio/metabolismo , Complexo de Golgi/metabolismo , Complexo de Golgi/efeitos dos fármacos , Ratos
6.
Proc Natl Acad Sci U S A ; 121(22): e2310677121, 2024 May 28.
Artigo em Inglês | MEDLINE | ID: mdl-38753503

RESUMO

Seasonal and pandemic-associated influenza strains cause highly contagious viral respiratory infections that can lead to severe illness and excess mortality. Here, we report on the optimization of our small-molecule inhibitor F0045(S) targeting the influenza hemagglutinin (HA) stem with our Sulfur-Fluoride Exchange (SuFEx) click chemistry-based high-throughput medicinal chemistry (HTMC) strategy. A combination of SuFEx- and amide-based lead molecule diversification and structure-guided design led to identification and validation of ultrapotent influenza fusion inhibitors with subnanomolar EC50 cellular antiviral activity against several influenza A group 1 strains. X-ray structures of six of these compounds with HA indicate that the appended moieties occupy additional pockets on the HA surface and increase the binding interaction, where the accumulation of several polar interactions also contributes to the improved affinity. The compounds here represent the most potent HA small-molecule inhibitors to date. Our divergent HTMC platform is therefore a powerful, rapid, and cost-effective approach to develop bioactive chemical probes and drug-like candidates against viral targets.


Assuntos
Antivirais , Glicoproteínas de Hemaglutininação de Vírus da Influenza , Glicoproteínas de Hemaglutininação de Vírus da Influenza/metabolismo , Glicoproteínas de Hemaglutininação de Vírus da Influenza/química , Humanos , Antivirais/farmacologia , Antivirais/química , Química Farmacêutica/métodos , Ensaios de Triagem em Larga Escala/métodos , Influenza Humana/tratamento farmacológico , Influenza Humana/virologia , Cristalografia por Raios X/métodos , Química Click/métodos , Animais , Vírus da Influenza A/efeitos dos fármacos , Células Madin Darby de Rim Canino , Inibidores de Proteínas Virais de Fusão/farmacologia , Inibidores de Proteínas Virais de Fusão/química , Cães
7.
Nat Chem Biol ; 20(1): 62-73, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-37474759

RESUMO

Cells interpret a variety of signals through G-protein-coupled receptors (GPCRs) and stimulate the generation of second messengers such as cyclic adenosine monophosphate (cAMP). A long-standing puzzle is deciphering how GPCRs elicit different physiological responses despite generating similar levels of cAMP. We previously showed that some GPCRs generate cAMP from both the plasma membrane and the Golgi apparatus. Here we demonstrate that cardiomyocytes distinguish between subcellular cAMP inputs to elicit different physiological outputs. We show that generating cAMP from the Golgi leads to the regulation of a specific protein kinase A (PKA) target that increases the rate of cardiomyocyte relaxation. In contrast, cAMP generation from the plasma membrane activates a different PKA target that increases contractile force. We further validated the physiological consequences of these observations in intact zebrafish and mice. Thus, we demonstrate that the same GPCR acting through the same second messenger regulates cardiac contraction and relaxation dependent on its subcellular location.


Assuntos
Transdução de Sinais , Peixe-Zebra , Camundongos , Animais , AMP Cíclico/metabolismo , Sistemas do Segundo Mensageiro , Miócitos Cardíacos , Receptores Acoplados a Proteínas G/metabolismo
8.
Chem Rev ; 124(16): 9609-9632, 2024 Aug 28.
Artigo em Inglês | MEDLINE | ID: mdl-39052522

RESUMO

Recycling mixed polyolefin plastics is a significant challenge due to the limitations in sorting and degraded mechanical properties of blends. Nonreactive compatibilization by adding a small amount of polymeric additive is a widespread approach to restoring the performance and value of recycled plastics. Over the past several decades, synthetic advances have enabled access to low-cost copolymers and precision architectures for deepening the understanding of compatibilization mechanisms in semicrystalline polyolefins. This review covers the design parameters of a polymeric compatibilizer, the testing of blends, the synthetic methods of producing economically viable additives, and surveys the literature of blends of compatibilized HDPE, LLDPE, LDPE, and iPP. From this, readers should gain a comprehension of the polymer mechanics, synthesis, and macromolecular engineering of processable polyolefin blends, along with the field's future directions.

9.
Nat Mater ; 23(8): 1077-1084, 2024 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-38589541

RESUMO

Robust ferroelectricity in nanoscale fluorite oxide-based thin films enables promising applications in silicon-compatible non-volatile memories and logic devices. However, the polar orthorhombic (O) phase of fluorite oxides is a metastable phase that is prone to transforming into the ground-state non-polar monoclinic (M) phase, leading to macroscopic ferroelectric degradation. Here we investigate the reversibility of the O-M phase transition in ZrO2 nanocrystals via in situ visualization of the martensitic transformation at the atomic scale. We reveal that the reversible shear deformation pathway from the O phase to the monoclinic-like (M') state, a compressive-strained M phase, is protected by 90° ferroelectric-ferroelastic switching. Nevertheless, as the M' state gradually accumulates localized strain, a critical tensile strain can pin the ferroelastic domain, resulting in an irreversible M'-M strain relaxation and the loss of ferroelectricity. These findings demonstrate the key role of ferroelastic switching in the reversibility of phase transition and also provide a tensile-strain threshold for stabilizing the metastable ferroelectric phase in fluorite oxide thin films.

10.
Chem Rev ; 123(6): 2950-3006, 2023 Mar 22.
Artigo em Inglês | MEDLINE | ID: mdl-36802557

RESUMO

The net rate of a reversible chemical reaction is the difference between unidirectional rates of traversal along forward and reverse reaction paths. In a multistep reaction sequence, the forward and reverse trajectories, in general, are not the microscopic reverse of one another; rather, each unidirectional route is comprised of distinct rate-controlling steps, intermediates, and transition states. Consequently, traditional descriptors of rate (e.g., reaction orders) do not reflect intrinsic kinetic information but instead conflate unidirectional contributions determined by (i) the microscopic occurrence of forward/reverse reactions (i.e., unidirectional kinetics) and (ii) the reversibility of reaction (i.e., nonequilibrium thermodynamics). This review aims to provide a comprehensive resource of analytical and conceptual tools which deconvolute the contributions of reaction kinetics and thermodynamics to disambiguate unidirectional reaction trajectories and precisely identify rate- and reversibility-controlling molecular species and steps in reversible reaction systems. The extrication of mechanistic and kinetic information from bidirectional reactions is accomplished through equation-based formalisms (e.g., De Donder relations) grounded in principles of thermodynamics and interpreted in the context of theories of chemical kinetics developed in the past 25 years. The aggregate of mathematical formalisms detailed herein is general to thermochemical and electrochemical reactions and encapsulates a diverse body of scientific literature encompassing chemical physics, thermodynamics, chemical kinetics, catalysis, and kinetic modeling.

11.
Cell Mol Life Sci ; 81(1): 82, 2024 Feb 10.
Artigo em Inglês | MEDLINE | ID: mdl-38340178

RESUMO

Interaction between programmed death-1 (PD-1) ligand 1 (PD-L1) on tumor cells and PD-1 on T cells allows tumor cells to evade T cell-mediated immune surveillance. Strategies targeting PD-1/PD-L1 have shown clinical benefits in a variety of cancers. However, limited response rates in hepatocellular carcinoma (HCC) have prompted us to investigate the molecular regulation of PD-L1. Here, we identify B cell lymphoma-2-associated transcription factor 1 (BCLAF1) as a key PD-L1 regulator in HCC. Specifically, BCLAF1 interacts with SPOP, an E3 ligase that mediates the ubiquitination and degradation of PD-L1, thereby competitively inhibiting SPOP-PD-L1 interaction and subsequent ubiquitination and degradation of PD-L1. Furthermore, we determined an SPOP-binding consensus (SBC) motif mediating the BCLAF1-SPOP interaction on BCLAF1 protein and mutation of BCLAF1-SBC motif disrupts the regulation of the SPOP-PD-L1 axis. In addition, BCLAF1 expression was positively correlated with PD-L1 expression and negatively correlated with biomarkers of T cell activation, including CD3 and CD8, as well as with the level of immune cell infiltration in HCC tissues. Besides, BCLAF1 depletion leads to a significant reduction of PD-L1 expression in vitro, and this reduction of PD-L1 promoted T cell-mediated cytotoxicity. Notably, overexpression of BCLAF1 sensitized tumor cells to checkpoint therapy in an in vitro HCC cells-Jurkat cells co-culture model, whereas BCLAF1-SBC mutant decreased tumor cell sensitivity to checkpoint therapy, suggesting that BCLAF1 and its SBC motif serve as a novel therapeutic target for enhancing anti-tumor immunity in HCC.


Assuntos
Carcinoma Hepatocelular , Neoplasias Hepáticas , Humanos , Antígeno B7-H1/genética , Antígeno B7-H1/metabolismo , Carcinoma Hepatocelular/metabolismo , Linhagem Celular , Neoplasias Hepáticas/metabolismo , Proteínas Nucleares/genética , Proteínas Nucleares/metabolismo , Receptor de Morte Celular Programada 1 , Proteínas Repressoras/genética , Proteínas Supressoras de Tumor , Evasão da Resposta Imune/genética
12.
Nucleic Acids Res ; 51(5): 2011-2032, 2023 03 21.
Artigo em Inglês | MEDLINE | ID: mdl-36617428

RESUMO

Transfer RNA (tRNA) molecules are essential to decode messenger RNA codons during protein synthesis. All known tRNAs are heavily modified at multiple positions through post-transcriptional addition of chemical groups. Modifications in the tRNA anticodons are directly influencing ribosome decoding and dynamics during translation elongation and are crucial for maintaining proteome integrity. In eukaryotes, wobble uridines are modified by Elongator, a large and highly conserved macromolecular complex. Elongator consists of two subcomplexes, namely Elp123 containing the enzymatically active Elp3 subunit and the associated Elp456 hetero-hexamer. The structure of the fully assembled complex and the function of the Elp456 subcomplex have remained elusive. Here, we show the cryo-electron microscopy structure of yeast Elongator at an overall resolution of 4.3 Å. We validate the obtained structure by complementary mutational analyses in vitro and in vivo. In addition, we determined various structures of the murine Elongator complex, including the fully assembled mouse Elongator complex at 5.9 Å resolution. Our results confirm the structural conservation of Elongator and its intermediates among eukaryotes. Furthermore, we complement our analyses with the biochemical characterization of the assembled human Elongator. Our results provide the molecular basis for the assembly of Elongator and its tRNA modification activity in eukaryotes.


The multi-subunit Elongator complex mediates the addition of a carboxymethyl group to wobble uridines in eukaryotic tRNAs. This tRNA modification is crucial to preserve the integrity of cellular proteomes and to protects us against severe neurodegenerative diseases. Elongator is organized in two distinct modules (i) the larger Elp123 subcomplex that binds and modifies the suitable tRNA substrate and (ii) the smaller Elp456 subcomplex that assists the release of the modified tRNA. The presented cryo-EM structures of Elongator show that the assemblies are very dynamic and undergo conformational rearrangements at consecutive steps of the process. Last but not least, the study provides a detailed reaction scheme and shows that the architecture of Elongator is highly conserved from yeast to mammals.


Assuntos
Complexos Multiproteicos , Elongação Traducional da Cadeia Peptídica , Proteínas de Ligação a RNA , Saccharomyces cerevisiae , Animais , Humanos , Camundongos , Microscopia Crioeletrônica , Histona Acetiltransferases/metabolismo , Ligação Proteica , RNA de Transferência/metabolismo , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/metabolismo , Proteínas de Saccharomyces cerevisiae/metabolismo , Complexos Multiproteicos/química , Complexos Multiproteicos/ultraestrutura
13.
Proc Natl Acad Sci U S A ; 119(40): e2204666119, 2022 Oct 04.
Artigo em Inglês | MEDLINE | ID: mdl-36161954

RESUMO

Given the high energy density and eco-friendly characteristics, lithium-carbon dioxide (Li-CO2) batteries have been considered to be a next-generation energy technology to promote carbon neutral and space exploration. However, Li-CO2 batteries suffer from sluggish reaction kinetics, causing large overpotential and poor energy efficiency. Here, we observe enhanced reaction kinetics in aprotic Li-CO2 batteries with unconventional phase 4H/face-centered cubic (fcc) iridium (Ir) nanostructures grown on gold template. Significantly, 4H/fcc Ir exhibits superior electrochemical performance over fcc Ir in facilitating the round-trip reaction kinetics of Li+-mediated CO2 reduction and evolution, achieving a low charge plateau below 3.61 V and high energy efficiency of 83.8%. Ex situ/in situ studies and theoretical calculations reveal that the boosted reaction kinetics arises from the highly reversible generation of amorphous/low-crystalline discharge products on 4H/fcc Ir via the Ir-O coupling. The demonstration of flexible Li-CO2 pouch cells with 4H/fcc Ir suggests the feasibility of using unconventional phase nanomaterials in practical scenarios.

14.
Nano Lett ; 2024 Jun 06.
Artigo em Inglês | MEDLINE | ID: mdl-38842462

RESUMO

The aggravated mechanical and structural degradation of layered oxide cathode materials upon high-voltage charging invariably causes fast capacity fading, but the underlying degradation mechanisms remain elusive. Here we report a new type of mechanical degradation through the formation of a kink band in a Mg and Ti co-doped LiCoO2 cathode charged to 4.55 V (vs Li/Li+). The local stress accommodated by the kink band can impede crack propagation, improving the structural integrity in a highly delithiated state. Additionally, machine-learning-aided atomic-resolution imaging reveals that the formation of kink bands is often accompanied by the transformation from the O3 to O1 phase, which is energetically favorable as demonstrated by first-principles calculations. Our results provide new insights into the mechanical degradation mechanism of high-voltage LiCoO2 and the coupling between electrochemically triggered mechanical failures and structural transition, which may provide valuable guidance for enhancing the electrochemical performance of high-voltage layered oxide cathode materials for lithium-ion batteries.

15.
Diabetologia ; 67(11): 2459-2470, 2024 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-39207471

RESUMO

AIMS/HYPOTHESIS: Although the benefits of sodium-glucose cotransporter 2 inhibitor (SGLT2i) use in chronic kidney disease (CKD) are well established, the effects of these therapeutic agents in patients with advanced CKD are less certain. We hypothesised that the continued use of these drugs, even when renal function deteriorates to stage 4 CKD or worse, is safe and associated with improved cardiorenal survival. METHODS: This is a retrospective cohort study utilising data from medical records from two institutions. All patients with type 2 diabetes mellitus who were prescribed an SGLT2i between 1 January 2016 and 31 December 2021, who subsequently had eGFR <30 ml/min per 1.73 m2 recorded on two occasions at least 90 days apart, were identified. The date on which the eGFR first reached any level less than 30 ml/min per 1.73 m2 was defined as the index date. Individuals were then categorised into the SGLT2i continuation group or the discontinuation group according to the use of SGLT2i after the index date. Inverse probability of treatment weighting (IPTW) was performed to minimise confounding. Outcomes of interest included heart failure outcomes, cardiovascular outcomes, renal outcomes and safety outcomes. RESULTS: According to the eligibility criteria, 337 patients in the continuation group and 358 in the discontinuation group were identified. After IPTW, continuation of SGLT2i use was associated with significantly lower risks of the composite of major adverse cardiovascular events compared with discontinuation of SGLT2i use (HR 0.65 [95% CI 0.43, 0.99]), largely driven by reduced risk of myocardial infarction during follow-up (subdistribution HR [SHR] 0.43 [95% CI 0.21, 0.89]). The incidences of an eGFR decline of 50% or more (SHR 0.58 [95% CI 0.42, 0.81]) and all-cause hospital admission (SHR 0.77 [95% CI 0.64, 0.94]) were also significantly lower in the continuation group. None of the studied safety outcomes were significantly different when comparing the two groups. Blood haemoglobin levels were significantly higher in the continuation group at the end of follow-up (114.6 g/l vs 110.4 g/l, with a difference of 4.12 g/l; p=0.047). CONCLUSIONS/INTERPRETATION: In patients with CKD who were treated with an SGLT2i, continuation of SGLT2i use after eGFR declined to 30 ml/min per 1.73 m2 or less was associated with lower risks of cardiovascular and renal events compared with discontinuation of SGLT2i use. Continued use of SGLT2i throughout the course of CKD should be considered to optimise patient outcomes.


Assuntos
Diabetes Mellitus Tipo 2 , Taxa de Filtração Glomerular , Insuficiência Renal Crônica , Inibidores do Transportador 2 de Sódio-Glicose , Humanos , Inibidores do Transportador 2 de Sódio-Glicose/uso terapêutico , Masculino , Feminino , Estudos Retrospectivos , Diabetes Mellitus Tipo 2/tratamento farmacológico , Diabetes Mellitus Tipo 2/complicações , Insuficiência Renal Crônica/tratamento farmacológico , Pessoa de Meia-Idade , Idoso , Taxa de Filtração Glomerular/efeitos dos fármacos , Rim/efeitos dos fármacos , Rim/fisiopatologia , Doenças Cardiovasculares
16.
J Biol Chem ; 299(8): 104966, 2023 08.
Artigo em Inglês | MEDLINE | ID: mdl-37380076

RESUMO

tRNAs are short noncoding RNAs responsible for decoding mRNA codon triplets, delivering correct amino acids to the ribosome, and mediating polypeptide chain formation. Due to their key roles during translation, tRNAs have a highly conserved shape and large sets of tRNAs are present in all living organisms. Regardless of sequence variability, all tRNAs fold into a relatively rigid three-dimensional L-shaped structure. The conserved tertiary organization of canonical tRNA arises through the formation of two orthogonal helices, consisting of the acceptor and anticodon domains. Both elements fold independently to stabilize the overall structure of tRNAs through intramolecular interactions between the D- and T-arm. During tRNA maturation, different modifying enzymes posttranscriptionally attach chemical groups to specific nucleotides, which not only affect translation elongation rates but also restrict local folding processes and confer local flexibility when required. The characteristic structural features of tRNAs are also employed by various maturation factors and modification enzymes to assure the selection, recognition, and positioning of specific sites within the substrate tRNAs. The cellular functional repertoire of tRNAs continues to extend well beyond their role in translation, partly, due to the expanding pool of tRNA-derived fragments. Here, we aim to summarize the most recent developments in the field to understand how three-dimensional structure affects the canonical and noncanonical functions of tRNA.


Assuntos
Anticódon , RNA de Transferência , Conformação de Ácido Nucleico , RNA de Transferência/genética , RNA de Transferência/metabolismo , Anticódon/metabolismo , Biossíntese de Proteínas , Ribossomos/metabolismo
17.
J Am Chem Soc ; 146(32): 22247-22256, 2024 Aug 14.
Artigo em Inglês | MEDLINE | ID: mdl-39079042

RESUMO

Solid-phase polymer synthesis, historically rooted in peptide synthesis, has evolved into a powerful method for achieving sequence-controlled macromolecules. This study explores solid-phase polymer synthesis by covalently immobilizing growing polymer chains onto a poly(ethylene glycol) (PEG)-based resin, known as ChemMatrix (CM) resin. In contrast to traditional hydrophobic supports, CM resin's amphiphilic properties enable swelling in both polar and nonpolar solvents, simplifying filtration, washing, and drying processes. Combining atom transfer radical polymerization (ATRP) with solid-phase techniques allowed for the grafting of well-defined block copolymers in high yields. This approach is attractive for sequence-controlled polymer synthesis, successfully synthesizing di-, tri-, tetra-, and penta-block copolymers with excellent control over the molecular weight and dispersity. The study also delves into the limitations of achieving high molecular weights due to confinement within resin pores. Moreover, the versatility of the method is demonstrated through its applicability to various monomers in organic and aqueous media. This straightforward approach offers a rapid route to developing tailored block copolymers with unique structures and functionalities.

18.
Int J Cancer ; 155(11): 2021-2035, 2024 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-39081132

RESUMO

Neoadjuvant chemoradiotherapy (NCRT) followed by surgery is a standard treatment for locally advanced esophageal squamous cell carcinomas (ESCCs). However, the evolution of genome and immunogenome in ESCCs driven by NCRT remains incompletely elucidated. We performed whole-exome sequencing of 51 ESCC tumors collected before and after NCRT, 36 of which were subjected to transcriptome sequencing. Clonal analysis identified clonal extinction in 13 ESCC patients wherein all pre-NCRT clones disappeared after NCRT, and clonal persistence in 9 patients wherein clones endured following NCRT. The clone-persistent patients showed higher pre-NCRT genomic intratumoral heterogeneity and worse prognosis than the clone-extinct ones. In contrast to the clone-extinct patients, the clone-persistent patients demonstrated a high proportion of subclonal neoantigens within pre-treatment specimens. Transcriptome analysis revealed increased immune infiltrations and up-regulated immune-related pathways after NCRT, especially in the clone-extinct patients. The number of T cell receptor-neoantigen interactions was higher in the clone-extinct patients than in the clone-persistent ones. The decrease in T cell repertoire evenness positively correlated to the decreased number of clonal neoantigens after NCRT, especially in the clone-extinct patients. In conclusion, we identified two prognosis-related clonal dynamic modes driven by NCRT in ESCCs. This study extended our knowledge of the ESCC genome and immunogenome evolutions driven by NCRT.


Assuntos
Neoplasias Esofágicas , Carcinoma de Células Escamosas do Esôfago , Terapia Neoadjuvante , Humanos , Carcinoma de Células Escamosas do Esôfago/genética , Carcinoma de Células Escamosas do Esôfago/terapia , Carcinoma de Células Escamosas do Esôfago/imunologia , Carcinoma de Células Escamosas do Esôfago/patologia , Terapia Neoadjuvante/métodos , Neoplasias Esofágicas/genética , Neoplasias Esofágicas/terapia , Neoplasias Esofágicas/imunologia , Neoplasias Esofágicas/patologia , Masculino , Feminino , Pessoa de Meia-Idade , Idoso , Prognóstico , Sequenciamento do Exoma , Antígenos de Neoplasias/genética , Antígenos de Neoplasias/imunologia , Perfilação da Expressão Gênica , Transcriptoma , Quimiorradioterapia/métodos , Adulto
19.
Hum Mol Genet ; 31(18): 3161-3180, 2022 09 10.
Artigo em Inglês | MEDLINE | ID: mdl-35567414

RESUMO

RTL1/PEG11, which has been associated with anxiety disorders, is a retrotransposon-derived imprinted gene in the placenta. However, imprinting patterns and functions of RTL1 in the brain have not been well-investigated. We found Rtl1 was paternally, but not maternally, expressed in brain stem, thalamus, and hypothalamus of mice, and imprinting status of RTL1 was maintained in human brain. Paternal Rtl1 knockout (Rtl1m+/p-) mice had higher neonatal death rates due to impaired suckling, and low body weights beginning on embryonic day 16.5. High paternal expression of Rtl1 was detected in the locus coeruleus (LC) and Rtl1m+/p- mice showed an increased delay in time of onset for action potentials and inward currents with decreased neuronal excitability of LC neurons. Importantly, Rtl1m+/p- mice exhibited behaviors associated with anxiety, depression, fear-related learning and memory, social dominance, and low locomotor activity. Taken together, our findings demonstrate RTL1 is imprinted in brain, mediates emotional and social behaviors, and regulates excitability in LC neurons.


Assuntos
Proteínas da Gravidez , Retroelementos , Animais , Ansiedade/genética , Transtornos de Ansiedade/genética , Feminino , Impressão Genômica , Humanos , Locus Cerúleo/metabolismo , Camundongos , Neurônios/metabolismo , Gravidez , Proteínas da Gravidez/genética , Proteínas da Gravidez/metabolismo , Comportamento Social
20.
Am J Gastroenterol ; 2024 Jan 22.
Artigo em Inglês | MEDLINE | ID: mdl-38084857

RESUMO

INTRODUCTION: Despite the serious risks of diabetes with hepatitis C virus (HCV) infection, this preventable comorbidity is rarely a priority for HCV elimination. We aim to examine how a shared care model could eliminate HCV in patients with diabetes (PwD) in primary care. METHODS: There were 27 community-based Diabetes Health Promotion Institutes in each township/city of Changhua, Taiwan. PwD from these institutes from January 2018 to December 2020 were enrolled. HCV screening and treatment were integrated into diabetes structured care through collaboration between diabetes care and HCV care teams. Outcome measures included HCV care continuum indicators. Township/city variation in HCV infection prevalence and care cascades were also examined. RESULTS: Of the 10,684 eligible PwD, 9,984 (93.4%) underwent HCV screening, revealing a 6.18% (n = 617) anti-HCV seroprevalence. Among the 597 eligible seropositive individuals, 507 (84.9%) completed the RNA test, obtaining 71.8% positives. Treatment was initiated by 327 (89.8%) of 364 viremic patients, and 315 (86.5%) completed it, resulting in a final cure rate of 79.4% (n = 289). Overall, with the introduction of antivirals in this cohort, the prevalence of viremic HCV infection dropped from 4.44% to 1.34%, yielding a 69.70% (95% credible interval 63.64%-77.03%) absolute reduction. DISCUSSION: Although HCV prevalence varied, the care cascades achieved consistent results across townships/cities. We have further successfully implemented the model in county-wide hospital-based diabetes clinics, eventually treating 89.6% of the total PwD. A collaborative effort between diabetes care and HCV elimination enhanced the testing and treatment in PwD through an innovative shared care model.

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