RESUMO
A biocompatible metal-organic framework (MOF), named HSTC-4, constructed using the flexible 4,4'-oxybis(benzoic acid) (OBA), was developed to enable efficient loading and controlled release of vitamin C (VC) through a combination of strategies involving ligand length, structure design, and metal selection. The kinetic product HSTC-4 demonstrates a propensity for transforming into the thermodynamically stable HSTC-5 under external stimuli, such as photoillumination and vacuum heating, as witnessed by single-crystal to single-crystal transformation. Density functional theory (DFT) calculations reveal that the VC guest molecules exhibit stronger binding affinity with HSTC-5 due to its narrower pores compared to HSTC-4, resulting in a slower release of VC from VC@HSTC-5. Furthermore, precise control over VC release can be achieved by introducing surface modifications involving SiO2 onto the structure of VC@HSCT-5, while simultaneously adjusting environmental factors such as pH and temperature conditions. Preliminary cell culture experiments and cytotoxicity assays highlight the biocompatibility of HSTC-5, suggesting that it is a promising platform for sustained drug delivery and diverse biomedical applications.
Assuntos
Ácido Ascórbico , Estruturas Metalorgânicas , Termodinâmica , Estruturas Metalorgânicas/química , Estruturas Metalorgânicas/farmacologia , Ácido Ascórbico/química , Cinética , Humanos , Teoria da Densidade Funcional , Sobrevivência Celular/efeitos dos fármacos , Portadores de Fármacos/química , Estrutura Molecular , Liberação Controlada de FármacosRESUMO
BACKGROUND: In minimally invasive surgery (MIS), trainees need to learn how to interpret the operative field displayed on the laparoscopic screen. Experts currently guide trainees mainly verbally during laparoscopic procedures. A newly developed telestration system with augmented reality (iSurgeon) allows the instructor to display hand gestures in real-time on the laparoscopic screen in augmented reality to provide visual expert guidance (telestration). This study analysed the effect of telestration guided instructions on gaze behaviour during MIS training. METHODS: In a randomized-controlled crossover study, 40 MIS naive medical students performed 8 laparoscopic tasks with telestration or with verbal instructions only. Pupil Core eye-tracking glasses were used to capture the instructor's and trainees' gazes. Gaze behaviour measures for tasks 1-7 were gaze latency, gaze convergence and collaborative gaze convergence. Performance measures included the number of errors in tasks 1-7 and trainee's ratings in structured and standardized performance scores in task 8 (ex vivo porcine laparoscopic cholecystectomy). RESULTS: There was a significant improvement 1-7 on gaze latency [F(1,39) = 762.5, p < 0.01, ηp2 = 0.95], gaze convergence [F(1,39) = 482.8, p < 0.01, ηp2 = 0.93] and collaborative gaze convergence [F(1,39) = 408.4, p < 0.01, ηp2 = 0.91] upon instruction with iSurgeon. The number of errors was significantly lower in tasks 1-7 (0.18 ± 0.56 vs. 1.94 ± 1.80, p < 0.01) and the score ratings for laparoscopic cholecystectomy were significantly higher with telestration (global OSATS: 29 ± 2.5 vs. 25 ± 5.5, p < 0.01; task-specific OSATS: 60 ± 3 vs. 50 ± 6, p < 0.01). CONCLUSIONS: Telestration with augmented reality successfully improved surgical performance. The trainee's gaze behaviour was improved by reducing the time from instruction to fixation on targets and leading to a higher convergence of the instructor's and the trainee's gazes. Also, the convergence of trainee's gaze and target areas increased with telestration. This confirms augmented reality-based telestration works by means of gaze guidance in MIS and could be used to improve training outcomes.
Assuntos
Realidade Aumentada , Educação Médica , Aprendizagem , Animais , Colecistectomia Laparoscópica/educação , Colecistectomia Laparoscópica/métodos , Competência Clínica , Estudos Cross-Over , Laparoscopia/educação , Suínos , Estudantes de Medicina , Educação Médica/métodos , HumanosRESUMO
Artificial sweeteners have sparked a heated debate worldwide due to their ambiguous impacts on public and environmental health and food safety and quality. Many studies on artificial sweeteners have been conducted; however, none scientometric studies exist in the field. This study aimed to elaborate on the knowledge creation and development of the field of artificial sweeteners and predict the frontiers of knowledge based on bibliometrics. In particular, this study combined VOSviewer, CiteSpace, and Bibliometrix to visualize the mapping of knowledge production, covered 2389 relevant scientific publications (1945-2022), and systematically analyzed articles and reviews (n = 2101). Scientific publications on artificial sweeteners have been growing at an annual rate of 6.28% and globally attracting 7979 contributors. Susan J. Brown with total publications (TP) of 17, average citation per article (AC) of 36.59, and Hirsch (h)-index of 12 and Robert F. Margolskee (TP = 12; AC = 2046; h-index = 11) were the most influential scholars. This field was clustered into four groups: eco-environment and toxicology, physicochemical mechanisms, public health and risks, and nutrition metabolism. The publications about environmental issues, in particular, "surface water," were most intensive during the last five years (2018-2022). Artificial sweeteners are gaining importance in the monitoring and assessment of environmental and public health. Results of the dual-map overlay showed that the future research frontiers tilt toward molecular biology, immunology, veterinary and animal sciences, and medicine. Findings of this study are conducive to identifying knowledge gaps and future research directions for scholars.
Assuntos
Bibliometria , Saúde Ambiental , Animais , Inocuidade dos Alimentos , Temperatura Alta , Estado Nutricional , PublicaçõesRESUMO
Atrial fibrillation (AF) is a cardiovascular epidemic that occurs primarily in the elderly with primary cardiovascular diseases, leading to severe consequences such as stroke and heart failure. The heart is an energy-consuming organ, which requires a high degree of metabolic flexibility to ensure a quick switch of metabolic substrates to meet its energy needs in response to physiological and pathological stimulation. Metabolism is closely related to the occurrence of AF, and AF patients manifest metabolic inflexibility, such as insulin resistance and the metabolic shift from aerobic metabolism to anaerobic glycolysis. Moreover, our research group and the others have shown that metabolic inflexibility is a crucial pathologic mechanism for AF. Energy metabolism is closely linked to the aging process and aging-related diseases, and impaired metabolic flexibility is considered as an essential driver of aging. Therefore, this review focuses on the alteration of metabolic flexibility in the elderly and reveals that impaired metabolic flexibility may be an important driver for the high prevalence of AF in the elderly, hoping to provide intervention strategies for the prevention and treatment of AF in the elderly.
Assuntos
Fibrilação Atrial , Insuficiência Cardíaca , Acidente Vascular Cerebral , Humanos , Idoso , Fibrilação Atrial/epidemiologia , Anticoagulantes , EnvelhecimentoRESUMO
Neurosteroids are endogenous modulators of neuronal excitability and nervous system development and are being developed as anesthetic agents and treatments for psychiatric diseases. While gamma amino-butyric acid Type A (GABAA) receptors are the primary molecular targets of neurosteroid action, the structural details of neurosteroid binding to these proteins remain ill defined. We synthesized neurosteroid analogue photolabeling reagents in which the photolabeling groups were placed at three positions around the neurosteroid ring structure, enabling identification of binding sites and mapping of neurosteroid orientation within these sites. Using middle-down mass spectrometry (MS), we identified three clusters of photolabeled residues representing three distinct neurosteroid binding sites in the human α1ß3 GABAA receptor. Novel intrasubunit binding sites were identified within the transmembrane helical bundles of both the α1 (labeled residues α1-N408, Y415) and ß3 (labeled residue ß3-Y442) subunits, adjacent to the extracellular domains (ECDs). An intersubunit site (labeled residues ß3-L294 and G308) in the interface between the ß3(+) and α1(-) subunits of the GABAA receptor pentamer was also identified. Computational docking studies of neurosteroid to the three sites predicted critical residues contributing to neurosteroid interaction with the GABAA receptors. Electrophysiological studies of receptors with mutations based on these predictions (α1-V227W, N408A/Y411F, and Q242L) indicate that both the α1 intrasubunit and ß3-α1 intersubunit sites are critical for neurosteroid action.
Assuntos
Proteínas de Membrana/metabolismo , Receptores de GABA/metabolismo , Animais , Sítios de Ligação , Linhagem Celular , Eletrofisiologia , Feminino , Citometria de Fluxo , Humanos , Espectrometria de Massas , Simulação de Acoplamento Molecular , Muscimol/metabolismo , Neurotransmissores/metabolismo , Oócitos/metabolismo , Xenopus laevisRESUMO
Epidermal growth factor receptor (EGFR) triple mutations with exon 19 deletion (del19), T790M, and cis-C797S (del19/T790M/cis-C797S mutations) frequently occur in patients with non-small cell lung cancer (NSCLC), while progression to frontline EGFR-tyrosine kinase inhibitors (TKIs) and osimertinib was resistant to all clinically available EGFR-TKIs. Brigatinib monotherapy may be a potential treatment for NSCLC harboring del19/T790M/cis-C797S mutations based on preclinical studies; however, no clinical report has evaluated its efficacy on EGFR del19/T790M/cis-C797S mutations. Herein, we present a case of a female patient with EGFR del19-mutated NSCLC treated with afatinib followed by osimertinib due to acquired T790M mutation. The EGFR del19/T790M/cis-C797S mutations were detected following osimertinib treatment. Complete response of skull metastasis was confirmed after brigatinib treatment (90 mg daily). Unfortunately, she experienced intolerable adverse events; therefore, brigatinib was discontinued after three-month usage. This report provides the first reported evidence for the use of brigatinib monotherapy in patients with NSCLC harboring EGFR del19/T790M/cis-C797S mutations after progression to previous EGFR-TKIs.
Assuntos
Carcinoma Pulmonar de Células não Pequenas , Neoplasias Pulmonares , Humanos , Feminino , Carcinoma Pulmonar de Células não Pequenas/tratamento farmacológico , Carcinoma Pulmonar de Células não Pequenas/genética , Carcinoma Pulmonar de Células não Pequenas/patologia , Neoplasias Pulmonares/tratamento farmacológico , Neoplasias Pulmonares/genética , Neoplasias Pulmonares/patologia , Receptores ErbB/metabolismo , Mutação , Inibidores de Proteínas Quinases/farmacologia , Inibidores de Proteínas Quinases/uso terapêutico , Resistencia a Medicamentos Antineoplásicos/genética , Compostos de Anilina/uso terapêutico , Compostos de Anilina/farmacologia , ÉxonsRESUMO
RESEARCH QUESTION: What are the risks associated with cryopreserved semen collected during and after the coronavirus disease 2019 (COVID-19) pandemic wave in Wuhan, China? DESIGN: Retrospective cohort study involving young adult men who were qualified sperm donors at the Hunan Province Human Sperm Bank (China) during the pandemic wave (1 January 2020 to 30 January 2020) and after the wave and return to work (7 April 2020 to 30 May 30 2020). One hundred paired semen and blood specimens from 100 donors were included. One-step single-tube nested quantitative real-time polymerase chain reaction (OSN-qRT-PCR) was used to detect SARS-CoV-2. Moreover, to control the unacceptable risk of false-negative results, a second round of screening was performed with pooled RNA from negative semen samples using crystal digital PCR (cd-PCR). RESULTS: For individual blood and semen samples, the target genes, namely the nucleocapsid protein (N) and open reading frame (ORF-1ab) genes, tested negative in all of the 100 paired samples. Further, as per cd-PCR results, there were >20,000 droplets per well in the RNA for each combined sample and no positive droplets were present for either of the aforementioned target genes. A total of 100 paired semen and blood samples from these two groups tested negative for SARS-CoV-2. CONCLUSIONS: Cryopreserved semen at the Hunan Province Human Sperm Bank during and after the COVID-19 pandemic wave was free of SARS-CoV-2 and was judged safe for external use in the future.
Assuntos
COVID-19 , Pandemias , China/epidemiologia , Humanos , Masculino , Reação em Cadeia da Polimerase em Tempo Real , Estudos Retrospectivos , SARS-CoV-2 , Sêmen , Bancos de Esperma , Espermatozoides , Adulto JovemRESUMO
BACKGROUND: Anti-Mullerian hormone receptor type II (Amhr2) is a key receptor of Amh signaling in regulating gonad development. The amhr2 gene has been identified in numerous species, including a few teleost fishes. However, the roles of Amhr2 in Amh signaling in fish are poorly studied. METHODS AND RESULTS: In this study, an amhr2 homolog from obscure puffer (Takifugu obscurus) was identified, and its molecular characteristics were systematically analyzed. Expression analysis revealed that amhr2 was highly expressed in the gonads of adult pufferfish and significantly upregulated during sex differentiation. Significantly, a sex-linked SNP site was verified in obscure puffer amhr2. Females exhibited a homozygous genotype (C/C), while males possessed a heterozygous genotype (C/G), resulting in an amino acid variation (His/Asp384) in the kinase domain of Amhr2. Then, the functions of the different Amhr2 genotypes were further investigated. The male genotype protein (Amhr2D384) showed an enhanced ability to interact with the type I receptor (Bmpr1a) compared to the female genotype (Amhr2H384). The phosphorylation levels of Smads and activity of the target gene (id3) induced by the male genotype were also much higher than those induced by the female genotype. These results confirmed that the male genotype had an enhanced effect on the Amh signaling pathway compared with the female genotype. CONCLUSIONS: This study provides direct experimental evidence for the roles of different Amhr2 genotypes in pufferfish and suggests that amhr2 is responsible for male sex differentiation in obscure puffer.
Assuntos
Receptores de Peptídeos/genética , Receptores de Fatores de Crescimento Transformadores beta/genética , Diferenciação Sexual/genética , Takifugu/genética , Animais , Feminino , Heterozigoto , Homozigoto , Masculino , Mutação , Receptores de Peptídeos/metabolismo , Receptores de Fatores de Crescimento Transformadores beta/metabolismo , Transdução de Sinais/genéticaRESUMO
Neurosteroids are endogenous sterols that potentiate or inhibit pentameric ligand-gated ion channels (pLGICs) and can be effective anesthetics, analgesics, or anti-epileptic drugs. The complex effects of neurosteroids on pLGICs suggest the presence of multiple binding sites in these receptors. Here, using a series of novel neurosteroid-photolabeling reagents combined with top-down and middle-down mass spectrometry, we have determined the stoichiometry, sites, and orientation of binding for 3α,5α-pregnane neurosteroids in the Gloeobacter ligand-gated ion channel (GLIC), a prototypic pLGIC. The neurosteroid-based reagents photolabeled two sites per GLIC subunit, both within the transmembrane domain; one site was an intrasubunit site, and the other was located in the interface between subunits. By using reagents with photoreactive groups positioned throughout the neurosteroid backbone, we precisely map the orientation of neurosteroid binding within each site. Amino acid substitutions introduced at either site altered neurosteroid modulation of GLIC channel activity, demonstrating the functional role of both sites. These results provide a detailed molecular model of multisite neurosteroid modulation of GLIC, which may be applicable to other mammalian pLGICs.
Assuntos
Proteínas de Bactérias/metabolismo , Desoxicorticosterona/análogos & derivados , Canais Iônicos de Abertura Ativada por Ligante/metabolismo , Modelos Moleculares , Neurotransmissores/metabolismo , Pregnanos/metabolismo , Substituição de Aminoácidos , Proteínas de Bactérias/química , Proteínas de Bactérias/genética , Sítios de Ligação , Cianobactérias , Desoxicorticosterona/química , Desoxicorticosterona/metabolismo , Hidroxilação , Cinética , Canais Iônicos de Abertura Ativada por Ligante/química , Canais Iônicos de Abertura Ativada por Ligante/genética , Ligantes , Conformação Molecular , Simulação de Acoplamento Molecular , Mutagênese Sítio-Dirigida , Neurotransmissores/química , Marcadores de Fotoafinidade/química , Mutação Puntual , Pregnanos/química , Conformação Proteica , Domínios e Motivos de Interação entre Proteínas , Mapeamento de Interação de Proteínas , Multimerização Proteica , Proteínas Recombinantes/química , Proteínas Recombinantes/metabolismoRESUMO
BACKGROUND: Human adenoviruses are a common group of viruses that cause acute infectious diseases. Human adenovirus (HAdV) 3 and HAdV 7 cause major outbreaks of severe pneumonia. A reliable and practical method for HAdV typing in clinical laboratories is lacking. A simple, rapid and accurate molecular typing method for HAdV may facilitate clinical diagnosis and epidemiological control. METHODS: We developed and evaluated duplex real-time recombinase-aided amplification (RAA) assays incorporating competitive internal controls for detection of HAdV 3 and HAdV 7, respectively. The assays were performed in a one-step in a single tube reaction at 39° for 20 min. RESULTS: The analytical sensitivities of the duplex RAA assays for HAdV 3 and HAdV 7 were 5.0 and 14.8 copies per reaction, respectively (at 95% probability by probit regression analysis). No cross-reaction was observed with other types of HAdV or other common respiratory viruses. The duplex RAA assays were used to detect 152 previously-defined HAdV-positive samples. These results agreed with those obtained using a published triplex quantitative real-time PCR protocol. CONCLUSIONS: We provide the first report of internally-controlled duplex RAA assays for the detection of HAdV 3 and HAdV 7. These assays effectively reduce the rate of false negative results and may be valuable for detection of HAdV 3 and HAdV 7 in clinical laboratories, especially in resource-poor settings.
Assuntos
Adenovírus Humanos/isolamento & purificação , Técnicas de Amplificação de Ácido Nucleico/métodos , Técnicas de Amplificação de Ácido Nucleico/normas , Recombinases/genética , Adenovírus Humanos/genética , Humanos , Reação em Cadeia da Polimerase em Tempo Real/métodos , Reação em Cadeia da Polimerase em Tempo Real/normas , Infecções Respiratórias/epidemiologia , Sensibilidade e Especificidade , Sorogrupo , TemperaturaRESUMO
Voltage-dependent anion channel-1 (VDAC1) is a highly regulated ß-barrel membrane protein that mediates transport of ions and metabolites between the mitochondria and cytosol of the cell. VDAC1 co-purifies with cholesterol and is functionally regulated by cholesterol, among other endogenous lipids. Molecular modeling studies based on NMR observations have suggested five cholesterol-binding sites in VDAC1, but direct experimental evidence for these sites is lacking. Here, to determine the sites of cholesterol binding, we photolabeled purified mouse VDAC1 (mVDAC1) with photoactivatable cholesterol analogues and analyzed the photolabeled sites with both top-down mass spectrometry (MS), and bottom-up MS paired with a clickable, stable isotope-labeled tag, FLI-tag. Using cholesterol analogues with a diazirine in either the 7 position of the steroid ring (LKM38) or the aliphatic tail (KK174), we mapped a binding pocket in mVDAC1 localized to Thr83 and Glu73, respectively. When Glu73 was mutated to a glutamine, KK174 no longer photolabeled this residue, but instead labeled the nearby Tyr62 within this same binding pocket. The combination of analytical strategies employed in this work permits detailed molecular mapping of a cholesterol-binding site in a protein, including an orientation of the sterol within the site. Our work raises the interesting possibility that cholesterol-mediated regulation of VDAC1 may be facilitated through a specific binding site at the functionally important Glu73 residue.
Assuntos
Colesterol/química , Canal de Ânion 1 Dependente de Voltagem/química , Marcadores de Afinidade , Animais , Sítios de Ligação , Camundongos , Ressonância Magnética Nuclear Biomolecular , Canal de Ânion 1 Dependente de Voltagem/genéticaRESUMO
Identifying sites of protein-ligand interaction is important for structure-based drug discovery and understanding protein structure-function relationships. Mass spectrometry (MS) has emerged as a useful tool for identifying residues covalently modified by ligands. Current methods use database searches that are dependent on acquiring interpretable fragmentation spectra (MS2) of peptide-ligand adducts. This is problematic for identifying sites of hydrophobic ligand incorporation in integral membrane proteins (IMPs), where poor aqueous solubility and ionization of peptide-ligand adducts and collision-induced adduct loss hinder the acquisition of quality MS2 spectra. To address these issues, we developed a fast ligand identification (FLI) tag that can be attached to any alkyne-containing ligand via Cu(I)-catalyzed cycloaddition. The FLI tag adds charge to increase solubility and ionization, and utilizes stable isotope labeling for MS1 level identification of hydrophobic peptide-ligand adducts. The FLI tag was coupled to an alkyne-containing neurosteroid photolabeling reagent and used to identify peptide-steroid adducts in MS1 spectra via the stable heavy isotope pair. Peptide-steroid adducts were not identified in MS2-based database searches because collision-induced adduct loss was the dominant feature of collision-induced dissociation (CID) fragmentation, but targeted analysis of MS1 pairs using electron transfer dissociation (ETD) markedly reduced adduct loss. Using the FLI tag and ETD, we identified Glu73 as the site of photoincorporation of our neurosteroid ligand in the IMP, mouse voltage-dependent anion channel-1 (mVDAC1), and top-down MS confirmed a single site of photolabeling.
Assuntos
Ligantes , Peptídeos/química , Espectrometria de Massas em Tandem , Canal de Ânion 1 Dependente de Voltagem/metabolismo , Alcinos/química , Sequência de Aminoácidos , Animais , Cromatografia Líquida de Alta Pressão , Química Click , Interações Hidrofóbicas e Hidrofílicas , Marcação por Isótopo , Camundongos , Peptídeos/metabolismo , Solubilidade , Raios Ultravioleta , Canal de Ânion 1 Dependente de Voltagem/químicaRESUMO
Oxidative stress mediates the pathogenesis of neurodegenerative disorders. Gartanin, a natural xanthone of mangosteen, possesses multipharmacological activities. Herein, the neuroprotection capacity of gartanin against glutamate-induced damage in HT22 cells and its possible mechanism(s) were investigated for the first time. Glutamate resulted in cell death in a dose-dependent manner and supplementation of 1-10 µM gartanin prevented the detrimental effects of glutamate on cell survival. Additional investigations on the underlying mechanisms suggested that gartanin could effectively reduce glutamate-induced intracellular ROS generation and mitochondrial depolarization. We further found that gartanin induced HO-1 expression independent of nuclear factor erythroid-derived 2-like 2 (Nrf2). Subsequent studies revealed that the inhibitory effects of gartanin on glutamate-induced apoptosis were partially blocked by small interfering RNA-mediated knockdown of HO-1. Finally, the protein expression of phosphorylation of AMP-activated protein kinase (AMPK) and its downstream signal molecules, Sirtuin activator (SIRT1) and peroxisome proliferator-activated receptor-γ coactivator-1α (PGC-1α), increased after gartanin treatment. Taken together, these findings suggest gartanin is a potential neuroprotective agent against glutamate-induced oxidative injury partially through increasing Nrf-2-independed HO-1 and AMPK/SIRT1/PGC-1α signaling pathways.
Assuntos
Proteínas Quinases Ativadas por AMP/metabolismo , Apoptose/efeitos dos fármacos , Heme Oxigenase-1/metabolismo , Proteínas de Membrana/metabolismo , Fator 2 Relacionado a NF-E2/metabolismo , Neurônios/efeitos dos fármacos , Xantonas/farmacologia , Animais , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Ácido Glutâmico/farmacologia , Camundongos , Neurônios/citologia , Neurônios/metabolismo , Fármacos Neuroprotetores/farmacologia , Estresse Oxidativo/efeitos dos fármacos , Espécies Reativas de Oxigênio/metabolismo , Transdução de Sinais/efeitos dos fármacos , Xantonas/químicaRESUMO
Propofol is the most important intravenous general anesthetic in current clinical use. It acts by potentiating GABAA (γ-aminobutyric acid type A) receptors, but where it binds to this receptor is not known and has been a matter of some debate. We synthesized a new propofol analog photolabeling reagent whose biological activity is very similar to that of propofol. We confirmed that this reagent labeled known propofol binding sites in human serum albumin that have been identified using X-ray crystallography. Using a combination of protiated and deuterated versions of the reagent to label mammalian receptors in intact membranes, we identified a new binding site for propofol in GABAA receptors consisting of both ß3 homopentamers and α1ß3 heteropentamers. The binding site is located within the ß subunit at the interface between the transmembrane domains and the extracellular domain and lies close to known determinants of anesthetic sensitivity in the transmembrane segments TM1 and TM2.
Assuntos
Marcadores de Fotoafinidade/análise , Propofol/metabolismo , Receptores de GABA-A/química , Receptores de GABA-A/metabolismo , Sítios de Ligação , Humanos , Modelos Moleculares , Estrutura Molecular , Marcadores de Fotoafinidade/química , Propofol/química , Albumina Sérica/química , Relação Estrutura-AtividadeRESUMO
Bioassay-guided fractionation of the ethanolic extract of the stems of Aristolochia fordiana led to the isolation of six new dihydrobenzofuran neolignans (1-3 and 7-9), three new 2-aryldihydrobenzofurans (4-6), a new 8-O-4' neolignan (10), and 14 known analogues (11-24). The structures of compounds 1-10 were established by spectroscopic methods, and their absolute configurations were determined by analyses of the specific rotation and electronic circular dichroism data. The neuroprotective effects of compounds 1-24 against glutamate-induced cell death were tested in hippocampal neuronal cell line HT22. Compounds 17 and 20-24 exhibited moderate neuroprotective activity by increasing the endogenous antioxidant defense system. In addition, the neolignans activated the Nrf2 (nuclear factor E2-related factor 2) pathway, resulting in the increase of the expression of endogenous antioxidant protein HO-1 (heme oxygenase-1). The active compounds also preserved the levels of antiapoptotic protein Bcl-2 (B cell lymphoma/leukemia-2), which was decreased by glutamate. Collectively, these results suggested that the active neolignans protect neurons against glutamate-induced cell death through maintaining the Nrf2/HO-1 signaling pathway as well as preserving the Bcl-2 protein and might be promising novel beneficial agents for oxidative stress-associated diseases.
Assuntos
Aristolochia/química , Benzofuranos/isolamento & purificação , Benzofuranos/farmacologia , Medicamentos de Ervas Chinesas/isolamento & purificação , Medicamentos de Ervas Chinesas/farmacologia , Heme Oxigenase-1/metabolismo , Lignanas/isolamento & purificação , Lignanas/farmacologia , Fator 2 Relacionado a NF-E2/metabolismo , Neurônios/efeitos dos fármacos , Fármacos Neuroprotetores/isolamento & purificação , Fármacos Neuroprotetores/farmacologia , Estresse Oxidativo/efeitos dos fármacos , Antioxidantes/farmacologia , Apoptose/efeitos dos fármacos , Benzofuranos/química , Western Blotting , Morte Celular/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Medicamentos de Ervas Chinesas/química , Ácido Glutâmico/farmacologia , Hipocampo/citologia , L-Lactato Desidrogenase/análise , Lignanas/química , Estrutura Molecular , Fármacos Neuroprotetores/química , Ressonância Magnética Nuclear Biomolecular , Caules de Planta/química , Proteínas Proto-Oncogênicas c-bcl-2/efeitos dos fármacos , Espécies Reativas de Oxigênio/análise , Espécies Reativas de Oxigênio/metabolismo , Transdução de Sinais/efeitos dos fármacosRESUMO
The involvement of cytoskeleton-related proteins in regulating mitochondrial respiration has been revealed in mammalian cells. However, it is unclear if there is a relationship between the microtubule-based motor protein kinesin and mitochondrial respiration. In this research, we demonstrate that a plant-specific kinesin, Kinesin-like protein 1 (KP1; At KIN14 h), is involved in respiratory regulation during seed germination at a low temperature. Using in vitro biochemical methods and in vivo transgenic cell observations, we demonstrate that KP1 is able to localize to mitochondria via its tail domain (C terminus) and specifically interacts with a mitochondrial outer membrane protein, voltage-dependent anion channel 3 (VDAC3). Targeting of the KP1-tail to mitochondria is dependent on the presence of VDAC3. When grown at 4° C, KP1 dominant-negative mutants (TAILOEs) and vdac3 mutants exhibited a higher seed germination frequency. All germinating seeds of the kp1 and vdac3 mutants had increased oxygen consumption; the respiration balance between the cytochrome pathway and the alternative oxidase pathway was disrupted, and the ATP level was reduced. We conclude that the plant-specific kinesin, KP1, specifically interacts with VDAC3 on the mitochondrial outer membrane and that both KP1 and VDAC3 regulate aerobic respiration during seed germination at low temperature.
Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/metabolismo , Germinação , Cinesinas/metabolismo , Proteínas Mitocondriais/metabolismo , Canais de Ânion Dependentes de Voltagem/metabolismo , Trifosfato de Adenosina/análise , Arabidopsis/genética , Proteínas de Arabidopsis/genética , Respiração Celular , Citrato (si)-Sintase/análise , Temperatura Baixa , Cinesinas/genética , Mitocôndrias/genética , Mitocôndrias/metabolismo , Membranas Mitocondriais/metabolismo , Proteínas Mitocondriais/genética , Oxigênio/metabolismo , Plantas Geneticamente Modificadas/genética , Plantas Geneticamente Modificadas/metabolismo , Proteínas Recombinantes de Fusão/metabolismo , Sementes/crescimento & desenvolvimento , Sementes/metabolismo , Nicotiana/genética , Nicotiana/metabolismo , TransgenesRESUMO
The model compound [Zn(HCOO)2(4,4'-bipy)] (1; 4,4'-bipy = 4,4'-bipyridine) is selected in this work to demonstrate the effectiveness of our previously proposed design strategy for electron-transfer photochromic metal-organic complexes. The electron-transfer photochromic behavior of 1 has been discovered for the first time. Experimental and theoretical data illustrate that the photochromism of 1 can be attributed to the electron transfer from formato to 4,4'-bipy and the formation of a radical photoproduct. The electron transfer prefers to occur between formato and 4,4'-bipy, which are combined directly by the Zn(II) atoms. A high-contrast (up to 8.3 times) photoluminescence switch occurs during the photochromic process. The similarity of photochromic behaviors among 1 and its analogues as well as viologen compounds has also been found. Photochromic studies of this model compound indicate that new electron-transfer photochromic metal-organic complexes can be largely designed and synthesized by the rational assembly of nonphotochromic electron-donating and electron-accepting ligands.
RESUMO
Mass spectrometric sequencing of low abundance, integral membrane proteins, particularly the transmembrane domains, presents challenges that span the multiple phases of sample preparation including solubilization, purification, enzymatic digestion, peptide extraction, and chromatographic separation. We describe a method through which we have obtained high peptide coverage for 12 γ-aminobutyric acid type A receptor (GABAA receptor) subunits from 2 picomoles of affinity-purified GABAA receptors from rat brain neocortex. Focusing on the α1 subunit, we identified peptides covering 96% of the protein sequence from fragmentation spectra (MS2) using a database searching algorithm and deduced 80% of the amino acid residues in the protein from de novo sequencing of Orbitrap spectra. The workflow combined microscale membrane protein solubilization, protein delipidation, in-solution multi-enzyme digestion, multiple stationary phases for peptide extraction, and acquisition of high-resolution full scan and fragmentation spectra. For de novo sequencing of peptides containing the transmembrane domains, timed digestions with chymotrypsin were utilized to generate peptides with overlapping sequences that were then recovered by sequential solid phase extraction using a C4 followed by a porous graphitic carbon stationary phase. The specificity of peptide identifications and amino acid residue sequences was increased by high mass accuracy and charge state assignment to parent and fragment ions. Analysis of three separate brain samples demonstrated that 78% of the sequence of the α1 subunit was observed in all three replicates with an additional 13% covered in two of the three replicates, indicating a high degree of sequence coverage reproducibility. Label-free quantitative analysis was applied to the three replicates to determine the relative abundances of 11 γ-aminobutyric acid type A receptor subunits. The deep sequence MS data also revealed two N-glycosylation sites on the α1 subunit, confirmed two splice variants of the γ2 subunit (γ2L and γ2S) and resolved a database discrepancy in the sequence of the α5 subunit.
Assuntos
Espectrometria de Massas/métodos , Receptores de GABA-A/química , Análise de Sequência de Proteína/métodos , Sequência de Aminoácidos , Animais , Cromatografia Líquida , Eletroforese em Gel de Poliacrilamida , Dados de Sequência Molecular , Neocórtex , Peptídeos/química , Isoformas de Proteínas , Subunidades Proteicas/química , Ratos , Extração em Fase SólidaRESUMO
Primary myelofibrosis (PMF) is a myeloproliferative neoplasm with splenomegaly as the major clinical manifestation, which is commonly considered to be linked to splenic extramedullary hematopoiesis. Alteration of CXCL12/CXCR4 pathway can lead to the migration of hematopoietic stem cells and hematopoietic progenitor cells from bone marrow to spleen which results in splenic extramedullary hematopoiesis. In addition, low GATA1 expression and the abnormal secretion of cytokines were found to be significantly associated with splenomegaly. With the application of JAK1/2 inhibitors in clinical, the symptoms of splenomegaly have been significantly improved in PMF patients. This article will review the pathogenesis and targeted treatment progress of splenomegaly in PMF.
Assuntos
Inibidores de Janus Quinases , Mielofibrose Primária , Humanos , Esplenomegalia/complicações , Esplenomegalia/patologia , Esplenomegalia/terapia , Mielofibrose Primária/terapia , Medula Óssea/metabolismo , Baço , Células-Tronco Hematopoéticas , Inibidores de Janus Quinases/metabolismoRESUMO
Gen X and F-53B have been popularized as alternatives to PFOA and PFOS, respectively. These per(poly)fluoroalkyl substances pervasively coexist with microplastics (MPs) in aquatic environments. However, there are knowledge gaps regarding their potential eco-environmental risks. In this study, a typical free-floating macrophyte, Eichhornia crassipes (E. crassipes), was selected for hydroponic simulation of a single exposure to PFOA, PFOS, Gen X, and F-53B, and co-exposure with polystyrene (PS) microspheres. F-53B exhibited the highest bioaccumulation followed by Gen X, PFOA, and PFOS. In the presence of PS MPs, the bioavailabilities of the four PFASs shifted and the whole plant bioconcentration factors improved. All four PFASs induced severe lipid peroxidation, which was exacerbated by PS MPs. The highest integrated biomarker response (IBR) was observed for E. crassipes (IBR of shoot: 30.01, IBR of root: 22.79, and IBR of whole plant: 34.96) co-exposed to PS MPs and F-53B. The effect addition index (EAI) model revealed that PS MPs showed antagonistic toxicity with PFOA and PFOS (EAI < 0) and synergistic toxicity with Gen X and F-53B (EAI > 0). These results are helpful to compare the eco-environmental impacts of legacy and alternative PFASs for renewal process of PFAS consumption and provide toxicological, botanical, and ecoengineering insights under co-contamination with MPs.