RESUMO
Loss of the gene (Fmr1) encoding Fragile X mental retardation protein (FMRP) causes increased mRNA translation and aberrant synaptic development. We find neurons of the Fmr1-/y mouse have a mitochondrial inner membrane leak contributing to a "leak metabolism." In human Fragile X syndrome (FXS) fibroblasts and in Fmr1-/y mouse neurons, closure of the ATP synthase leak channel by mild depletion of its c-subunit or pharmacological inhibition normalizes stimulus-induced and constitutive mRNA translation rate, decreases lactate and key glycolytic and tricarboxylic acid (TCA) cycle enzyme levels, and triggers synapse maturation. FMRP regulates leak closure in wild-type (WT), but not FX synapses, by stimulus-dependent ATP synthase ß subunit translation; this increases the ratio of ATP synthase enzyme to its c-subunit, enhancing ATP production efficiency and synaptic growth. In contrast, in FXS, inability to close developmental c-subunit leak prevents stimulus-dependent synaptic maturation. Therefore, ATP synthase c-subunit leak closure encourages development and attenuates autistic behaviors.
Assuntos
Trifosfato de Adenosina/metabolismo , Síndrome do Cromossomo X Frágil/metabolismo , Subunidades Proteicas/metabolismo , Animais , Linhagem Celular , Ciclo do Ácido Cítrico/fisiologia , Fibroblastos/metabolismo , Proteína do X Frágil da Deficiência Intelectual/metabolismo , Células HEK293 , Humanos , Camundongos , Neurônios/metabolismo , RNA Mensageiro , Sinapses/metabolismoRESUMO
Nonimmune cells can have immunomodulatory roles that contribute to healthy development. However, the molecular and cellular mechanisms underlying the immunomodulatory functions of erythroid cells during human ontogenesis remain elusive. Here, integrated, single-cell transcriptomic studies of erythroid cells from the human yolk sac, fetal liver, preterm umbilical cord blood (UCB), term UCB and adult bone marrow (BM) identified classical and immune subsets of erythroid precursors with divergent differentiation trajectories. Immune-erythroid cells were present from the yolk sac to the adult BM throughout human ontogenesis but failed to be generated in vitro from human embryonic stem cells. Compared with classical-erythroid precursors, these immune-erythroid cells possessed dual erythroid and immune regulatory networks, showed immunomodulatory functions and interacted more frequently with various innate and adaptive immune cells. Our findings provide important insights into the nature of immune-erythroid cells and their roles during development and diseases.
Assuntos
Células Precursoras Eritroides , Transcriptoma , Adulto , Diferenciação Celular/genética , Células Eritroides , Sangue Fetal , Humanos , Recém-Nascido , Saco VitelinoRESUMO
ATP-sensitive potassium channels (KATP) couple intracellular ATP levels with membrane excitability. These channels play crucial roles in many essential physiological processes and have been implicated extensively in a spectrum of metabolic diseases and disorders. To gain insight into the mechanism of KATP, we elucidated the structure of a hetero-octameric pancreatic KATP channel in complex with a non-competitive inhibitor glibenclamide by single-particle cryoelectron microscopy to 5.6-Å resolution. The structure shows that four SUR1 regulatory subunits locate peripherally and dock onto the central Kir6.2 channel tetramer through the SUR1 TMD0-L0 fragment. Glibenclamide-bound SUR1 uses TMD0-L0 fragment to stabilize Kir6.2 channel in a closed conformation. In another structural population, a putative co-purified phosphatidylinositol 4,5-bisphosphate (PIP2) molecule uncouples Kir6.2 from glibenclamide-bound SUR1. These structural observations suggest a molecular mechanism for KATP regulation by anti-diabetic sulfonylurea drugs, intracellular adenosine nucleotide concentrations, and PIP2 lipid.
Assuntos
Canais KATP/química , Canais KATP/metabolismo , Subfamília B de Transportador de Cassetes de Ligação de ATP/química , Subfamília B de Transportador de Cassetes de Ligação de ATP/metabolismo , Animais , Microscopia Crioeletrônica , Humanos , Hidrolases/química , Hidrolases/metabolismo , Mamíferos/metabolismo , Mesocricetus , Camundongos , Modelos Moleculares , Fosfoinositídeo Fosfolipase C/química , Fosfoinositídeo Fosfolipase C/metabolismo , Canais de Potássio Corretores do Fluxo de Internalização/química , Canais de Potássio Corretores do Fluxo de Internalização/metabolismo , Receptores de Sulfonilureias/química , Receptores de Sulfonilureias/metabolismoRESUMO
The teleology of sex differences has been argued since at least as early as Aristotle's controversial Generation of Animals more than 300 years BC, which reflects the sex bias of the time to contemporary readers. Although the question "why are the sexes different" remains a topic of debate in the present day in metaphysics, the recent emphasis on sex comparison in research studies has led to the question "how are the sexes different" being addressed in health science through numerous observational studies in both health and disease susceptibility, including blood pressure regulation and hypertension. These efforts have resulted in better understanding of differences in males and females at the molecular level that partially explain their differences in vascular function and renal sodium handling and hence blood pressure and the consequential cardiovascular and kidney disease risks in hypertension. This review focuses on clinical studies comparing differences between men and women in blood pressure over the life span and response to dietary sodium and highlights experimental models investigating sexual dimorphism in the renin-angiotensin-aldosterone, vascular, sympathetic nervous, and immune systems, endothelin, the major renal sodium transporters/exchangers/channels, and the impact of sex hormones on these systems in blood pressure homeostasis. Understanding the mechanisms governing sex differences in blood pressure regulation could guide novel therapeutic approaches in a sex-specific manner to lower cardiovascular risks in hypertension and advance personalized medicine.
Assuntos
Hipertensão , Caracteres Sexuais , Animais , Feminino , Humanos , Masculino , Pressão Sanguínea/fisiologia , Rim , Hemodinâmica , SódioRESUMO
Induction of beige cells causes the browning of white fat and improves energy metabolism. However, the central mechanism that controls adipose tissue browning and its physiological relevance are largely unknown. Here, we demonstrate that fasting and chemical-genetic activation of orexigenic AgRP neurons in the hypothalamus suppress the browning of white fat. O-linked ß-N-acetylglucosamine (O-GlcNAc) modification of cytoplasmic and nuclear proteins regulates fundamental cellular processes. The levels of O-GlcNAc transferase (OGT) and O-GlcNAc modification are enriched in AgRP neurons and are elevated by fasting. Genetic ablation of OGT in AgRP neurons inhibits neuronal excitability through the voltage-dependent potassium channel, promotes white adipose tissue browning, and protects mice against diet-induced obesity and insulin resistance. These data reveal adipose tissue browning as a highly dynamic physiological process under central control, in which O-GlcNAc signaling in AgRP neurons is essential for suppressing thermogenesis to conserve energy in response to fasting.
Assuntos
Tecido Adiposo Marrom/metabolismo , Dieta , N-Acetilglucosaminiltransferases/metabolismo , Neurônios/metabolismo , Tecido Adiposo Branco/metabolismo , Proteína Relacionada com Agouti/metabolismo , Animais , Jejum , Feminino , Grelina/metabolismo , Hipotálamo/citologia , Hipotálamo/metabolismo , Resistência à Insulina , Masculino , Camundongos Endogâmicos C57BL , Camundongos Knockout , N-Acetilglucosaminiltransferases/genética , Obesidade/metabolismo , Obesidade/prevenção & controleRESUMO
To survive, mammalian cells must adapt to environmental challenges. While the cellular response to mild stress has been widely studied, how cells respond to severe stress remains unclear. We show here that under severe hyperosmotic stress, cells enter a transient hibernation-like state in anticipation of recovery. We demonstrate this adaptive pausing response (APR) is a coordinated cellular response that limits ATP supply and consumption through mitochondrial fragmentation and widespread pausing of mRNA translation. This pausing is accomplished by ribosome stalling at translation initiation codons, which keeps mRNAs poised to resume translation upon recovery. We further show that recovery from severe stress involves ISR (integrated stress response) signaling that permits cell cycle progression, resumption of growth, and reversal of mitochondria fragmentation. Our findings indicate that cells can respond to severe stress via a hibernation-like mechanism that preserves vital elements of cellular function under harsh environmental conditions.
Assuntos
Proliferação de Células , Fibroblastos/metabolismo , Mitocôndrias/metabolismo , Proteínas Mitocondriais/biossíntese , Pressão Osmótica , Biossíntese de Proteínas , Ribossomos/metabolismo , Adaptação Fisiológica , Trifosfato de Adenosina/metabolismo , Animais , Códon de Iniciação , Fibroblastos/patologia , Células HEK293 , Humanos , Cinética , Camundongos , Mitocôndrias/genética , Mitocôndrias/patologia , Proteínas Mitocondriais/genética , Ribossomos/genética , Transdução de SinaisRESUMO
Macrophages form a major cell population in the tumor microenvironment. They can be activated and polarized into tumor-associated macrophages (TAM) by the tumor-derived soluble molecules to promote tumor progression and metastasis. Here, we used comparative metabolomics coupled with biochemical and animal studies to show that cancer cells release succinate into their microenvironment and activate succinate receptor (SUCNR1) signaling to polarize macrophages into TAM. Furthermore, the results from in vitro and in vivo studies revealed that succinate promotes not only cancer cell migration and invasion but also cancer metastasis. These effects are mediated by SUCNR1-triggered PI3K-hypoxia-inducible factor 1α (HIF-1α) axis. Compared with healthy subjects and tumor-free lung tissues, serum succinate levels and lung cancer SUCNR1 expression were elevated in lung cancer patients, suggesting an important clinical relevance. Collectively, our findings indicate that the secreted tumor-derived succinate belongs to a novel class of cancer progression factors, controlling TAM polarization and promoting tumorigenic signaling.
Assuntos
Neoplasias Pulmonares/metabolismo , Neoplasias Pulmonares/patologia , Macrófagos/metabolismo , Metástase Neoplásica/patologia , Receptores Acoplados a Proteínas G/metabolismo , Ácido Succínico/metabolismo , Células A549 , Animais , Linhagem Celular Tumoral , Movimento Celular/fisiologia , Células HT29 , Humanos , Subunidade alfa do Fator 1 Induzível por Hipóxia/metabolismo , Células MCF-7 , Macrófagos/patologia , Camundongos Endogâmicos C57BL , Células PC-3 , Transdução de Sinais/fisiologia , Microambiente Tumoral/fisiologiaRESUMO
Arc is a synaptic protein essential for memory consolidation. Recent studies indicate that Arc originates in evolution from a Ty3-Gypsy retrotransposon GAG domain. The N-lobe of Arc GAG domain acquired a hydrophobic binding pocket in higher vertebrates that is essential for Arc's canonical function to weaken excitatory synapses. Here, we report that Arc GAG also acquired phosphorylation sites that can acutely regulate its synaptic function. CaMKII phosphorylates the N-lobe of the Arc GAG domain and disrupts an interaction surface essential for high-order oligomerization. In Purkinje neurons, CaMKII phosphorylation acutely reverses Arc's synaptic action. Mutant Arc that cannot be phosphorylated by CaMKII enhances metabotropic receptor-dependent depression in the hippocampus but does not alter baseline synaptic transmission or long-term potentiation. Behavioral studies indicate that hippocampus- and amygdala-dependent learning requires Arc GAG domain phosphorylation. These studies provide an atomic model for dynamic and local control of Arc function underlying synaptic plasticity and memory.
Assuntos
Proteína Quinase Tipo 2 Dependente de Cálcio-Calmodulina/metabolismo , Proteínas do Citoesqueleto/metabolismo , Potenciação de Longa Duração/fisiologia , Memória/fisiologia , Proteínas do Tecido Nervoso/metabolismo , Células de Purkinje/metabolismo , Sequência de Aminoácidos , Tonsila do Cerebelo/citologia , Tonsila do Cerebelo/metabolismo , Animais , Sítios de Ligação , Proteína Quinase Tipo 2 Dependente de Cálcio-Calmodulina/química , Proteína Quinase Tipo 2 Dependente de Cálcio-Calmodulina/genética , Proteínas do Citoesqueleto/química , Proteínas do Citoesqueleto/genética , Técnicas de Introdução de Genes , Células HEK293 , Hipocampo/citologia , Hipocampo/metabolismo , Humanos , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Modelos Moleculares , Proteínas do Tecido Nervoso/química , Proteínas do Tecido Nervoso/genética , Fosforilação , Ligação Proteica , Conformação Proteica em alfa-Hélice , Conformação Proteica em Folha beta , Domínios e Motivos de Interação entre Proteínas , Multimerização Proteica , Células de Purkinje/citologia , Alinhamento de Sequência , Homologia de Sequência de Aminoácidos , Sinapses/fisiologia , Transmissão SinápticaRESUMO
Phagocytes promptly resolve ingested targets to replenish lysosomes and maintain their responsiveness. The resolution process requires that degradative hydrolases, solute transporters, and proteins involved in lipid traffic are delivered and made active in phagolysosomes. It also involves extensive membrane remodeling. We report that cation channels that localize to phagolysosomes were essential for resolution. Specifically, the conductance of Na+ by two-pore channels (TPCs) and the presence of a Na+ gradient between the phagolysosome lumen and the cytosol were critical for the controlled release of membrane tension that permits deformation of the limiting phagolysosome membrane. In turn, membrane deformation was a necessary step to efficiently transport the cholesterol extracted from cellular targets, permeabilizing them to hydrolases. These results place TPCs as regulators of endomembrane remodeling events that precede target degradation in cases when the target is bound by a cholesterol-containing membrane. The findings may help to explain lipid metabolism dysfunction and autophagic flux impairment reported in TPC KO mice and establish stepwise regulation to the resolution process that begins with lysis of the target.
Assuntos
Fagossomos , Canais de Dois Poros , Camundongos , Animais , Fagossomos/metabolismo , Lisossomos/metabolismo , Hidrolases/metabolismo , Colesterol/metabolismoRESUMO
Peracetic acid (PAA) is emerging as a versatile agent for generating long-lived and selectively oxidative organic radicals (R-Oâ¢). Currently, the conventional transition metal-based activation strategies still suffer from metal ion leaching, undesirable by-products formation, and uncontrolled reactive species production. To address these challenges, we present a method employing BiOI with a unique electron structure as a PAA activator, thereby predominantly generating CH3C(O)O⢠radicals. The specificity of CH3C(O)O⢠generation ensured the superior performance of the BiOI/PAA system across a wide pH range (2.0 to 11.0), even in the presence of complex interfering substances such as humic acids, chloride ions, bicarbonate ions, and real-world water matrices. Unlike conventional catalytic oxidative methods, the BiOI/PAA system degrades sulfonamides without producing any toxic by-products. Our findings demonstrate the advantages of CH3C(O)O⢠in water decontamination and pave the way for the development of eco-friendly water decontaminations based on organic peroxides.
RESUMO
Malignant glioma exhibits immune evasion characterized by highly expressing the immune checkpoint CD47. RNA 5-methylcytosine(m5C) modification plays a pivotal role in tumor pathogenesis. However, the mechanism underlying m5C-modified RNA metabolism remains unclear, as does the contribution of m5C-modified RNA to the glioma immune microenvironment. In this study, we demonstrate that the canonical 28SrRNA methyltransferase NSUN5 down-regulates ß-catenin by promoting the degradation of its mRNA, leading to enhanced phagocytosis of tumor-associated macrophages (TAMs). Specifically, the NSUN5-induced suppression of ß-catenin relies on its methyltransferase activity mediated by cysteine 359 (C359) and is not influenced by its localization in the nucleolus. Intriguingly, NSUN5 directly interacts with and deposits m5C on CTNNB1 caRNA (chromatin-associated RNA). NSUN5-induced recruitment of TET2 to chromatin is independent of its methyltransferase activity. The m5C modification on caRNA is subsequently oxidized into 5-hydroxymethylcytosine (5hmC) by TET2, which is dependent on its binding affinity for Fe2+ and α-KG. Furthermore, NSUN5 enhances the chromatin recruitment of RBFOX2 which acts as a 5hmC-specific reader to recognize and facilitate the degradation of 5hmC caRNA. Notably, hmeRIP-seq analysis reveals numerous mRNA substrates of NSUN5 that potentially undergo this mode of metabolism. In addition, NSUN5 is epigenetically suppressed by DNA methylation and is negatively correlated with IDH1-R132H mutation in glioma patients. Importantly, pharmacological blockage of DNA methylation or IDH1-R132H mutant and CD47/SIRPα signaling synergistically enhances TAM-based phagocytosis and glioma elimination in vivo. Our findings unveil a general mechanism by which NSUN5/TET2/RBFOX2 signaling regulates RNA metabolism and highlight NSUN5 targeting as a potential strategy for glioma immune therapy.
Assuntos
5-Metilcitosina , 5-Metilcitosina/análogos & derivados , Proteínas de Ligação a DNA , Dioxigenases , Glioma , Proteínas Musculares , Humanos , 5-Metilcitosina/metabolismo , beta Catenina/metabolismo , Cromatina , Antígeno CD47/genética , RNA , Evasão da Resposta Imune , Glioma/patologia , RNA Mensageiro/metabolismo , Metiltransferases/metabolismo , RNA Nuclear Pequeno , Microambiente Tumoral , Fatores de Processamento de RNA/genética , Proteínas Repressoras/metabolismoRESUMO
RNA helicases are involved in the innate immune response against pathogens, including bacteria and viruses; however, their mechanism in the human airway epithelial cells is still not fully understood. Here, we demonstrated that DEAH (Asp-Glu-Ala-His) box polypeptide 35 (DHX35), a member of the DExD/H (Asp-Glu-x-Asp/His)-box helicase family, boosts antiviral innate immunity in human airway epithelial cells. DHX35 knockdown attenuated the production of interferon-ß (IFN-ß), IL6, and CXCL10, whereas DHX35 overexpression increased their production. Upon stimulation, DHX35 was constitutively expressed, but it translocated from the nucleus into the cytosol, where it recognized cytosolic poly(I:C) and poly(dA:dT) via its HELICc domain. Mitochondrial antiviral signaling protein (MAVS) acted as an adaptor for DHX35 and interacted with the HELICc domain of DHX35 using amino acids 360-510. Interestingly, DHX35 interacted with retinoic acid-inducible gene 1 (RIG-I), enhanced the binding affinity of RIG-I with poly(I:C) and poly(dA:dT), and formed a signalsome with MAVS to activate interferon regulatory factor 3 (IRF3), NF-κB-p65, and MAPK signaling pathways. These results indicate that DHX35 not only acted as a cytosolic nucleic acid sensor but also synergized with RIG-I to enhance antiviral immunity in human airway epithelial cells. Our results demonstrate a novel molecular mechanism for DHX35 in RIG-I-mediated innate immunity and provide a novel candidate for drug and vaccine design to control viral infections in the human airway.
Assuntos
Proteína DEAD-box 58 , RNA Helicases DEAD-box , Imunidade Inata , Receptores Imunológicos , Humanos , Proteína DEAD-box 58/metabolismo , Proteína DEAD-box 58/imunologia , RNA Helicases DEAD-box/metabolismo , RNA Helicases DEAD-box/imunologia , Receptores Imunológicos/metabolismo , Poli I-C/imunologia , Poli I-C/farmacologia , RNA Helicases/metabolismo , RNA Helicases/imunologia , Transdução de Sinais/imunologia , Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Proteínas Adaptadoras de Transdução de Sinal/imunologia , Células Epiteliais/imunologia , Células Epiteliais/metabolismo , Células Epiteliais/virologia , Células HEK293RESUMO
NAD+ biology is involved in controlling redox balance, functioning as a coenzyme in numerous enzymatic reactions, and is a cofactor for Sirtuin enzymes and a substrate for multiple regulatory enzyme reactions within and outside the cell. At the same time, NAD+ levels are diminished with aging and are consumed during the development of inflammatory and autoimmune diseases linked to aberrant immune activation. Direct NAD+ augmentation via the NAD+ salvage and Priess-Handler pathways is being investigated as a putative therapeutic intervention to improve the healthspan in inflammation-linked diseases. In this review, we survey NAD+ biology and its pivotal roles in the regulation of immunity and inflammation. Furthermore, we discuss emerging studies evaluate NAD+ boosting in murine models and in human diseases, and we highlight areas of research that remain unresolved in understanding the mechanisms of action of these nutritional supplementation strategies.
Assuntos
Doenças Autoimunes , NAD , Animais , Humanos , Camundongos , NAD/metabolismo , Autoimunidade , Oxirredução , InflamaçãoRESUMO
Assemblies of ß-amyloid (Aß) peptides are pathological mediators of Alzheimer's Disease (AD) and are produced by the sequential cleavages of amyloid precursor protein (APP) by ß-secretase (BACE1) and γ-secretase. The generation of Aß is coupled to neuronal activity, but the molecular basis is unknown. Here, we report that the immediate early gene Arc is required for activity-dependent generation of Aß. Arc is a postsynaptic protein that recruits endophilin2/3 and dynamin to early/recycling endosomes that traffic AMPA receptors to reduce synaptic strength in both hebbian and non-hebbian forms of plasticity. The Arc-endosome also traffics APP and BACE1, and Arc physically associates with presenilin1 (PS1) to regulate γ-secretase trafficking and confer activity dependence. Genetic deletion of Arc reduces Aß load in a transgenic mouse model of AD. In concert with the finding that patients with AD can express anomalously high levels of Arc, we hypothesize that Arc participates in the pathogenesis of AD.
Assuntos
Doença de Alzheimer/metabolismo , Precursor de Proteína beta-Amiloide/metabolismo , Proteínas do Citoesqueleto/metabolismo , Endossomos/metabolismo , Proteínas do Tecido Nervoso/metabolismo , Transporte Proteico , Animais , Membrana Celular/metabolismo , Humanos , Camundongos , Camundongos KnockoutRESUMO
Twisted two-dimensional bilayer materials exhibit many exotic electronic phenomena. Manipulating the 'twist angle' between the two layers enables fine control of the electronic band structure, resulting in magic-angle flat-band superconductivity1,2, the formation of moiré excitons3-8 and interlayer magnetism9. However, there are limited demonstrations of such concepts for photons. Here we show how analogous principles, combined with extreme anisotropy, enable control and manipulation of the photonic dispersion of phonon polaritons in van der Waals bilayers. We experimentally observe tunable topological transitions from open (hyperbolic) to closed (elliptical) dispersion contours in bilayers of α-phase molybdenum trioxide (α-MoO3), arising when the rotation between the layers is at a photonic magic twist angle. These transitions are induced by polariton hybridization and are controlled by a topological quantity. At the transitions the bilayer dispersion flattens, exhibiting low-loss tunable polariton canalization and diffractionless propagation with a resolution of less than λ0/40, where λ0 is the free-space wavelength. Our findings extend twistronics10 and moiré physics to nanophotonics and polaritonics, with potential applications in nanoimaging, nanoscale light propagation, energy transfer and quantum physics.
RESUMO
Bromodomain and extraterminal (BET) proteins are extensively studied in multiple pathologies, including cancer. BET proteins modulate transcription of various genes, including those synonymous with cancer, such as MYC. Thus, BET inhibitors are a major area of drug development efforts. (+)-JQ1 (JQ1) is the prototype inhibitor and is a common tool to probe BET functions. While showing therapeutic promise, JQ1 is not clinically usable, partly due to metabolic instability. Here, we show that JQ1 and the BET-inactive (-)-JQ1 are agonists of pregnane X receptor (PXR), a nuclear receptor that transcriptionally regulates genes encoding drug-metabolizing enzymes such as CYP3A4, which was previously shown to oxidize JQ1. A PXR-JQ1 co-crystal structure identified JQ1's tert-butyl moiety as a PXR anchor and explains binding by (-)-JQ1. Analogs differing at the tert-butyl lost PXR binding, validating our structural findings. Evaluation in liver cell models revealed both PXR-dependent and PXR-independent modulation of CYP3A4 expression by BET inhibitors. We have characterized a non-BET JQ1 target, a mechanism of physiological JQ1 instability, a biological function of (-)-JQ1, and BET-dependent transcriptional regulation of drug metabolism genes.
Assuntos
Azepinas , Receptor de Pregnano X , Triazóis , Azepinas/química , Azepinas/farmacologia , Linhagem Celular Tumoral , Proliferação de Células , Citocromo P-450 CYP3A/genética , Proteínas Nucleares/metabolismo , Receptor de Pregnano X/química , Proteínas Proto-Oncogênicas c-myc/genética , Receptores Citoplasmáticos e Nucleares , Triazóis/química , Triazóis/farmacologia , HumanosRESUMO
Allosteric regulation, induced by perturbations at an allosteric site topographically distinct from the orthosteric site, is one of the most direct and efficient ways to fine-tune macromolecular function. The Allosteric Database (ASD; accessible online at http://mdl.shsmu.edu.cn/ASD) has been systematically developed since 2009 to provide comprehensive information on allosteric regulation. In recent years, allostery has seen sustained growth and wide-ranging applications in life sciences, from basic research to new therapeutics development, while also elucidating emerging obstacles across allosteric research stages. To overcome these challenges and maintain high-quality data center services, novel features were curated in the ASD2023 update: (i) 66 589 potential allosteric sites, covering > 80% of the human proteome and constituting the human allosteric pocketome; (ii) 748 allosteric protein-protein interaction (PPI) modulators with clear mechanisms, aiding protein machine studies and PPI-targeted drug discovery; (iii) 'Allosteric Hit-to-Lead,' a pioneering dataset providing panoramic views from 87 well-defined allosteric hits to 6565 leads and (iv) 456 dualsteric modulators for exploring the simultaneous regulation of allosteric and orthosteric sites. Meanwhile, ASD2023 maintains a significant growth of foundational allosteric data. Based on these efforts, the allosteric knowledgebase is progressively evolving towards an integrated landscape, facilitating advancements in allosteric target identification, mechanistic exploration and drug discovery.
Assuntos
Sítio Alostérico , Bases de Conhecimento , Humanos , Regulação Alostérica , Descoberta de Drogas , Ligantes , Proteoma , Mapas de Interação de ProteínasRESUMO
Oral delivery is the most widely used and convenient route of administration of medicine. However, oral administration of hydrophilic macromolecules is commonly limited by low intestinal permeability and pre-systemic degradation in the gastrointestinal (GI) tract. Overcoming some of these challenges allowed emergence of oral dosage forms of peptide-based drugs in clinical settings. Antisense oligonucleotides (ASOs) have also been investigated for oral administration but despite the recent progress, the bioavailability remains low. Given the advancement with highly potent and durable trivalent N-acetylgalactosamine (GalNAc)-conjugated small interfering RNAs (siRNAs) via subcutaneous (s.c.) injection, we explored their activities after oral administration. We report robust RNA interference (RNAi) activity of orally administrated GalNAc-siRNAs co-formulated with permeation enhancers (PEs) in rodents and non-human primates (NHPs). The relative bioavailability calculated from NHP liver exposure was <2.0% despite minimal enzymatic degradation in the GI. To investigate the impact of oligonucleotide size on oral delivery, highly specific GalNAc-conjugated single-stranded oligonucleotides known as REVERSIRs with different lengths were employed and their activities for reversal of RNAi effect were monitored. Our data suggests that intestinal permeability is highly influenced by the size of oligonucleotides. Further improvements in the potency of siRNA and PE could make oral delivery of GalNAc-siRNAs as a practical solution.
Assuntos
Acetilgalactosamina , RNA Interferente Pequeno , Animais , Acetilgalactosamina/química , Acetilgalactosamina/metabolismo , RNA Interferente Pequeno/administração & dosagem , RNA Interferente Pequeno/farmacocinética , RNA Interferente Pequeno/química , RNA Interferente Pequeno/genética , RNA Interferente Pequeno/metabolismo , Administração Oral , Camundongos , Ratos , Interferência de RNA , Masculino , Disponibilidade Biológica , Humanos , Ratos Sprague-Dawley , Macaca fascicularis , Fígado/metabolismo , Macaca mulattaRESUMO
Photosynthesis of hydrogen peroxide (H2O2) by selective oxygen reduction is a green and cost-effective alternative to the energy-intensive anthraquinone process. Although inexpensive polymeric graphitic carbon nitride (g-C3N4) exhibits the ability to produce H2O2, its disordered and amorphous structure leads to a high recombination rate of photogenerated carriers and hinders charge transfer between layers. Herein, we predict that stacked polymeric g-C3N4 with ion intercalation (K+ and I-) can improve carrier separation and transfer by multiscale computational simulations. The electronic structures of g-C3N4 were tailored and modified by intercalating K+ and I- into the layer-by-layer structures. Guided by the computational predictions, we achieved efficient solar-driven H2O2 production by employing this facile and ion-intercalated crystalline g-C3N4. An H2O2 production rate of 13.1 mM g-1 h-1 and an apparent quantum yield of 23.6% at 400 nm were obtained. The synergistic effects of crystallinity regulation and dual interstitial doping engineering triggered the formation of new light absorption centers, the establishment of rapid charge diffusion channels, and the enhancement of two-electron oxygen reduction characteristics. This work sheds light on the dual tuning of crystallinity and electronic structure and broadens the design principles of organic-conjugated polymer photocatalysts for environmental remediation and energy conservation.
RESUMO
Singlet oxygen (1O2) plays a pivotal role in numerous catalytic oxidation processes utilized in water purification and chemical synthesis. The spin-trapping method based on electron paramagnetic resonance (EPR) analysis is commonly employed for 1O2 detection. However, it is often limited to time-independent acquisition. Recent studies have raised questions about the reliability of the 1O2 trapper, 2,2,6,6-tetramethylpiperidine (TEMP), in various systems. In this study, we introduce a comprehensive, kinetic examination to monitor the spin-trapping process in EPR analysis. The EPR intensity of the trapping product was used as a quantitative measurement to evaluate the concentration of 1O2 in aqueous systems. This in situ kinetic study was successfully applied to a classical photocatalytic system with exceptional accuracy. Furthermore, we demonstrated the feasibility of our approach in more intricate 1O2-driven catalytic oxidation processes for water decontamination and elucidated the molecular mechanism of direct TEMP oxidation. This method can avoid the false-positive results associated with the conventional 2D 1O2 detection techniques, and provide insights into the reaction mechanisms in 1O2-dominated catalytic oxidation processes. This work underscores the necessity of kinetic studies for spin-trapping EPR analysis, presenting an avenue for a comprehensive exploration of the mechanisms governing catalytic oxidation processes.