Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 46
Filtrar
1.
Respir Res ; 25(1): 57, 2024 Jan 25.
Artículo en Inglés | MEDLINE | ID: mdl-38267973

RESUMEN

BACKGROUND: Lymphangioleiomyomatosis (LAM) is a rare disease which is easily misdiagnosed. Vascular endothelial growth factor D (VEGF-D), as the most common biomarker, however, is not so perfect for the diagnosis and severity assessment of LAM. MATERIALS AND METHODS: The isobaric tags for relative and absolute quantitation (iTRAQ)-based method was used to identify a cytoskeleton protein, moesin. 84 patients with LAM, 44 patients with other cystic lung diseases (OCLDs), and 37 healthy control subjects were recruited for collecting blood samples and clinical data. The levels of moesin in serum were evaluated by ELISA. The relationships of moesin with lymphatic involvement, lung function, and treatment decision were explored in patients with LAM. RESULTS: The candidate protein moesin was identified by the proteomics-based bioinformatic analysis. The serum levels of moesin were higher in patients with LAM [219.0 (118.7-260.5) pg/mL] than in patients with OCLDs (125.8 ± 59.9 pg/mL, P < 0.0001) and healthy women [49.6 (35.5-78.9) ng/mL, P < 0.0001]. Moesin had an area under the receiver operator characteristic curve (AUC) of 0.929 for predicting LAM diagnosis compared to healthy women (sensitivity 81.0%, specificity 94.6%). The combination of moesin and VEGF-D made a better prediction in differentiating LAM from OCLDs than moesin or VEGF-D alone. Moreover, elevated levels of moesin were related to lymphatic involvement in patients with LAM. Moesin was found negatively correlated with FEV1%pred, FEV1/FVC, and DLCO%pred (P = 0.0181, r = - 0.3398; P = 0.0067, r = - 0.3863; P = 0.0010, r = - 0.4744). A composite score combining moesin and VEGF-D improved prediction for sirolimus treatment, compared with each biomarker alone. CONCLUSION: Higher levels of moesin in serum may indicate impaired lung function and lymphatic involvement in patients with LAM, suggest a more serious condition, and provide clinical guidance for sirolimus treatment.


Asunto(s)
Linfangioleiomiomatosis , Proteínas de Microfilamentos , Humanos , Femenino , Linfangioleiomiomatosis/diagnóstico , Factor D de Crecimiento Endotelial Vascular , Biomarcadores , Sirolimus
2.
BMC Pulm Med ; 24(1): 76, 2024 Feb 09.
Artículo en Inglés | MEDLINE | ID: mdl-38336682

RESUMEN

BACKGROUND: Severe asthma places a large burden on patients and society. The characteristics of patients with severe asthma in the Chinese population remain unclear. METHODS: A retrospective review was conducted in patients with severe asthma. Demographic and clinical data were collected. Patients were grouped according to phenotypes in terms of exacerbations, body mass index (BMI) and fixed airway obstruction (FAO) status, and the characteristics of different groups were compared. Comorbidities, factors that influence asthma phenotypes, were also analyzed in the study. RESULTS: A total of 228 patients with severe asthma were included in our study. They were more likely to be overweight or obese. A total of 41.7% of the patients received GINA step 5 therapy, and 43.4% had a history of receiving regular or intermittent oral corticosteroids (OCS). Severe asthmatic patients with comorbidities were prone to have more asthma symptoms and decreased quality of life than patients without comorbidities. Patients with exacerbations were characterized by longer duration of asthma, poorer lung function, and worse asthma control. Overweight or obese patients tended to have more asthma symptoms, poorer lung function and more asthma-related comorbidities. Compared to patients without FAO, those in the FAO group were older, with longer duration of asthma and more exacerbations. CONCLUSION: The existence of comorbidities in patients with severe asthma could result in more asthma symptoms and decreased quality of life. Patients with exacerbations or with overweight or obese phenotypes were characterized by poorer lung function and worse asthma control. Patients with FAO phenotype tended to have more exacerbations.


Asunto(s)
Obstrucción de las Vías Aéreas , Asma , Humanos , Sobrepeso/epidemiología , Calidad de Vida , Asma/tratamiento farmacológico , Obstrucción de las Vías Aéreas/epidemiología , Obesidad/epidemiología
3.
Pharm Dev Technol ; 29(5): 457-467, 2024 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-38629738

RESUMEN

This experiment aimed to investigate the feasibility of cytisine (CYT) in treating eye diseases with ocular topical application. An in vitro cytotoxicity test, a hen's egg test-chorioallantoic membrane (HET-CAM), and a mouse eye tolerance test were used to fully reveal the ocular safety profiles of CYT. For the efficacy evaluations, CYT's effects on cell wound healing, against H2O2-induced oxidative stress damages on cells, and on benzalkonium chloride (BAC)-induced dry eye disease (DED) in mice were evaluated. Results showed that CYT did not show any cytotoxicities at concentrations no higher than 250 µg/ml, while lipoic acid (α-LA) at 250 µg/ml and BAC at 1.25 µg/ml showed significant cytotoxicities within 48 h incubation. The HET-CAM and mouse eye tolerance test confirmed that 0.5% CYT eye drops demonstrated good safety characteristics. Efficacy evaluations showed that CTY significantly promoted cell migration and wound healing. CYT significantly improved cell survival against H2O2-induced oxidative stress damage by reversing the imbalance between the reactive oxygen species (ROS) and antioxidant defense mechanisms. The animal evaluation of the BAC-induced dry eye model revealed that CYT demonstrated a strong treatment effect, including reversing ocular surface damages, recovering corneal sensitivity, and inhibiting neovascularization; HMGB1/NF-κB signaling was involved in this DED treatment by CTY. In conclusion, CYT had strong experimental treatment efficacy against DED with good ocular safety profiles, and it might be a novel and promising drug for DED.


Asunto(s)
Alcaloides , Azocinas , Compuestos de Benzalconio , Síndromes de Ojo Seco , Soluciones Oftálmicas , Estrés Oxidativo , Quinolizinas , Animales , Quinolizinas/administración & dosificación , Quinolizinas/farmacología , Síndromes de Ojo Seco/tratamiento farmacológico , Síndromes de Ojo Seco/inducido químicamente , Compuestos de Benzalconio/administración & dosificación , Ratones , Soluciones Oftálmicas/administración & dosificación , Alcaloides/farmacología , Alcaloides/administración & dosificación , Estrés Oxidativo/efectos de los fármacos , Azocinas/administración & dosificación , Azocinas/farmacología , Humanos , Supervivencia Celular/efectos de los fármacos , Peróxido de Hidrógeno , Especies Reactivas de Oxígeno/metabolismo , Cicatrización de Heridas/efectos de los fármacos , Femenino , Antioxidantes/farmacología , Antioxidantes/administración & dosificación , Membrana Corioalantoides/efectos de los fármacos , Masculino , Alcaloides de Quinolizidina
4.
Bioorg Med Chem ; 80: 117176, 2023 02 15.
Artículo en Inglés | MEDLINE | ID: mdl-36709571

RESUMEN

A series of 2-oximino-2-indolylacetamide derivatives were designed, synthesized and evaluated for their antitumour effects. Among them, 4d exhibited the most potent antiproliferative effect in vitro on the tested human cancer cells. Additionally, 4d significantly induced cell apoptosis, caused mitochondrial dysfunction, promoted Bax, cleaved-PARP and p53 expression and inhibited Bcl-2 expression in 5-8F cells. Moreover, 4d remarkably promoted autophagosome formation, leading to cell apoptosis. Further investigation indicated that 4d could trigger cell death through cell ferroptosis, including increased ROS generation and lipid peroxidation and decreased glutathione peroxidase 4 (GPx4) expression and glutathione (GSH) levels. More importantly, 4d induced 5-8F cell death by activating ROS/MAPK and inhibiting the AKT/mTOR and STAT3 signalling pathways. Interestingly, 4d significantly suppressed tumour growth in a 5-8F cell xenograft model without obvious toxicity to mice. Overall, these results demonstrate that 4d may be a potential compound for cancer therapy.


Asunto(s)
Antineoplásicos , Ferroptosis , Humanos , Animales , Ratones , Especies Reactivas de Oxígeno/metabolismo , Apoptosis , Antineoplásicos/farmacología , Glutatión/metabolismo , Autofagia
5.
Chem Biodivers ; 20(7): e202300387, 2023 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-37336788

RESUMEN

Three new compounds (1-2, 14), as well as 22 known compounds (3-13, 15-25), were extracted for the first time from the Selaginella effusa Alston (S. effusa). For the unknown compounds, the planar configurations were determined via NMR and by high-resolution mass spectrometry, while their absolute configurations were determined by calculated electronic circular dichroism (ECD), and the configuration of the stereogenic center of biflavones 4-5 were established for the first time. The pure compounds (1-25) were tested in vitro to determine the inhibitory activity of the enzyme-catalyzed reactions. Compounds 1-9 inhibited α-glucosidase with IC50 values ranging from 0.30±0.02 to 4.65±0.04 µM and kinetic analysis of enzyme inhibition indicated that biflavones 1-3 were mixed-type α-glucosidase inhibitors. Compounds 12-13 showed excellent inhibitory activity against urease, with compound 12 (IC50 =4.38±0.31 µM) showing better inhibitory activity than the positive control drug AHA (IC50 13.52±0.61 µM). In addition, molecular docking techniques were used to simulate inhibitor-enzyme binding and to estimate the binding posture of the α-glucosidase and urease catalytic sites.


Asunto(s)
Selaginellaceae , alfa-Glucosidasas , Simulación del Acoplamiento Molecular , alfa-Glucosidasas/metabolismo , Selaginellaceae/metabolismo , Ureasa/metabolismo , Cinética , Inhibidores de Glicósido Hidrolasas/farmacología , Inhibidores de Glicósido Hidrolasas/química , Estructura Molecular
6.
Respir Res ; 22(1): 178, 2021 Jun 14.
Artículo en Inglés | MEDLINE | ID: mdl-34126986

RESUMEN

BACKGROUND: Serine peptidase inhibitor, clade B, member 10 (SERPINB10) contributes to allergic inflammation in asthma. However, its role in the T-helper type 2 (Th2) response of allergic asthma is not known. The goal of this study was to unveil the function of SERPINB10 in the Th2 response of allergic asthma and the mechanism by which SERPINB10 affects the viability of Th2 cells. METHODS: Th2 cytokines and serum levels of house dust mite (HDM)-specific IgE in bronchoalveolar lavage fluid were examined by ELISA in an HDM-induced asthma model. The number and apoptosis of Th1 and Th2 cells in mouse lungs were measured by flow cytometry. Naïve CD4 T cells from patients with asthma were cultured under appropriate polarizing conditions to generate Th1 and Th2 cells. SERPINB10 expression in polarized Th1 and Th2 cells was quantified by real-time reverse transcription-quantitative polymerase chain reaction. SERPINB10 expression was knocked down in human CD4 T cells with lentivirus. RESULTS: Knockdown of SERPINB10 expression significantly diminished HDM-induced Th2 cytokine secretion and level of HDM-specific IgE. After HDM exposure, SERPINB10-knockdown mice had diminished numbers of Th2 cells, but similar numbers of Th1 cells, compared with those in negative-control mice. Th2 cells of SERPINB10-knockdown mice were more susceptible to apoptosis than that of control mice. Stimulating T-cell receptors (TCRs) with anti-CD3 antibody caused upregulation of SERPINB10 expression in polarized Th2 cells, but not polarized Th1 cells. Knockdown of SERPINB10 expression resulted in fewer numbers and greater apoptosis of polarized Th2 cells. CONCLUSION: Our results suggest that SERPINB10 may contribute to allergic inflammation and the Th2 response of asthma by inhibiting the apoptosis of Th2 cells.


Asunto(s)
Alérgenos/inmunología , Apoptosis/genética , Asma/genética , Regulación de la Expresión Génica , Inmunidad Celular , Serpinas/genética , Células Th2/patología , Animales , Asma/inmunología , Asma/patología , Modelos Animales de Enfermedad , Ensayo de Inmunoadsorción Enzimática , Femenino , Ratones , Ratones Endogámicos C57BL , Serpinas/biosíntesis , Células Th2/inmunología
7.
Org Biomol Chem ; 19(9): 2055-2062, 2021 Mar 11.
Artículo en Inglés | MEDLINE | ID: mdl-33599668

RESUMEN

A new asymmetric activation strategy for hydrazones as acyl anion equivalents is developed in the bimetallic catalyzed carbonyl-ene reaction of isatins and hydrazones. Under mild conditions, optically active functionalized 3-hydroxy-2-oxindoles were furnished in up to 98% yield with up to 97% enantioselectivity. In this process, formaldehyde tert-butylhydrazone which is seldom employed in asymmetric carbonyl-ene reactions accelerated by a metallic catalyst can be activated well by a Brønsted base. A possible catalytic cycle is proposed.

8.
Mycopathologia ; 186(1): 1-13, 2021 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-33184749

RESUMEN

BACKGROUND: Allergic bronchopulmonary aspergillosis (ABPA) constantly develops in asthmatics, which has not been fully investigated. OBJECTIVES: This study aimed to investigate serum differentially expressed proteins (DEPs) between ABPA and asthma using the new approach isobaric tags by relative and absolute quantitation (iTRAQ). METHODS: Each 16 serum samples from ABPA or asthmatic subjects were pooled and screened using iTRAQ. After bioinformatic analysis, five candidate DEPs were validated in the enlarged serum samples from additional 21 ABPA, 31 asthmatic and 20 healthy subjects using ELISA. A receiver operating characteristic (ROC) curve was used to estimate the diagnostic power of carnosine dipeptidase 1 (CNDP1). RESULTS: A total of 29 DEPs were screened out between ABPA and asthmatic groups. Over half of them were enriched in proteolysis and regulation of protein metabolic process. Further verification showed serum levels of immunoglobulin heavy constant gamma 1, α-1-acid glycoprotein 1, corticosteroid-binding globulin and vitronectin were neither differentially altered between ABPA and asthma nor consistent with the proteomic analysis. Only serum CNDP1 was significantly decreased in ABPA patients, compared with asthmatics and healthy controls (P < 0.01 and P < 0.05). The ROC analysis determined 10.73 ng/mL as the cutoff value of CNDP1, which could distinguish ABPA among asthmatics (AUC 0.770, 95%CI 0.632-0.875, P < 0.001). CONCLUSIONS: This study firstly identified serological DEPs between ABPA and asthma using the new technique iTRAQ. Serum CNDP1 might assist the differential diagnosis of ABPA from asthma and serve as a new pathogenetic factor in fungal colonization and sensitization.


Asunto(s)
Aspergilosis Broncopulmonar Alérgica , Asma , Aspergillus fumigatus/inmunología , Asma/diagnóstico , Diagnóstico Diferencial , Humanos , Inmunoglobulina E , Proteómica
9.
J Org Chem ; 85(4): 2266-2276, 2020 02 21.
Artículo en Inglés | MEDLINE | ID: mdl-31920086

RESUMEN

The stereoselective sequential spirocyclopropanation/Cloke-Wilson rearrangement reactions have been developed to synthesize γ-butyrolactones using alkylidene Meldrum's acids and benzyl halides. The DBU-promoted spirocyclopropanation was carried out efficiently at room temperature to generate trans-isomeric spirocyclopropyl Meldrum's acid, and the following stereospecific thermal decarboxylative Cloke-Wilson rearrangement afforded trans-γ-butyrolactones. A variety of aromatic and aliphatic Meldrum's acid derived olefins and benzyl halides were tolerated. Various trans-ß,γ-disubstituted γ-butyrolactones were produced with moderate to good overall yields from 46 to 96% and excellent diastereoselectivities.

10.
Org Biomol Chem ; 17(10): 2684-2690, 2019 03 06.
Artículo en Inglés | MEDLINE | ID: mdl-30768085

RESUMEN

The Michael addition initiated ring closure reaction of barbiturate-based olefins and acetylacetone with NBS has been explored. The efficient and chemoselective approach for the synthesis of barbiturate-fused spirocycles was established. Spirodihydrofuryl barbiturates and spirocyclopropyl barbiturates were synthesized selectively via cascade reactions under different basic conditions in moderate to excellent yields. The structure of 2-(4-chlorophenyl)-1,1-diacetyl-5,7-dimethyl-5,7-diazaspiro[2,5]octane-4,6,8-trione was confirmed by single crystal X-ray diffraction analysis.

11.
Gen Comp Endocrinol ; 272: 76-82, 2019 02 01.
Artículo en Inglés | MEDLINE | ID: mdl-30508509

RESUMEN

Ghrelin, one of the most important appetite regulating peptides, is involved in the regulation of energy homeostasis. The anorexia effect of ghrelin in chickens is contrary to that of ghrelin in mammals. In the present study, the effects of feeding status and dietary energy level on plasma total ghrelin levels and expression were studied in broilers. The gene expression of ghrelin and its receptor GHS-R1a were measured in the hypothalamus, proventriculus, duodenum, liver, and abdominal fat pad. The results showed that ghrelin mRNA and GHS-R1a mRNA are moderately expressed in liver and abdominal fat. Ghrelin secretion was increased by fasting and refeeding. The gene expression of ghrelin and GHS-R1a in the hypothalamus, proventriculus, liver, and abdominal fat pad were changed by feeding status and dietary energy level. The results suggest that ghrelin is a signal of energy utilization in chickens. The abundant expression of ghrelin and GHS-R1a in liver and abdominal fat pad may be associated with energy balance.


Asunto(s)
Metabolismo Energético/genética , Ghrelina/metabolismo , Animales , Pollos , Homeostasis , Masculino
12.
Gen Comp Endocrinol ; 268: 14-21, 2018 11 01.
Artículo en Inglés | MEDLINE | ID: mdl-30016627

RESUMEN

Ghrelin is one of the most important appetite regulating peptides, involved in the regulation of energy homeostasis. The role of ghrelin on the appetite and fat metabolism in chickens is different from that of ghrelin in mammals. Glucocorticoids and insulin are important hormones and work differently in energy regulation of body. In this study, the effects of dexamethasone (DEX, 2.0 mg/kg BW), subcutaneous insulin injection (40 µg/kg BW), and glucose load on ghrelin secretion and expression were determined in broilers. DEX treatment increased circulating ghrelin concentration in broiler fed with either a low-energy diet (11.05 MJ/kg of metabolizable energy) or a high-energy diet (14.44 MJ/kg of metabolizable energy). The expression levels of ghrelin were increased while both ghrelin and its receptor GHS-R1a expression levels were stimulated by DEX. A single subcutaneous insulin injection (40 µg/kg BW) or oral glucose infusion (2 g/kg BW) rise circulating ghrelin level. Ghrelin expression in the proventriculus was increased by insulin treatment but unchanged by glucose load. DEX had no detectable influence on ghrelin and GHS-R1a expression in the hypohtalamus, whereas insulin suppressed their expression. In conclusion, both insulin and glucocorticoid stimulate ghrelin secretion in chickens, in contrast to mammals. Glucocorticoids evoke peripheral ghrelin/GHS-R1a system while insulin increases peripheral ghrelin expression and suppress the activation of central ghrelin/GHS-R1a system. The result suggests that ghrelin involved in the modulating network of energy homeostasis in concert with glucocorticoids and insulin.


Asunto(s)
Apetito/fisiología , Dexametasona/metabolismo , Metabolismo Energético/fisiología , Ghrelina/metabolismo , Insulina/metabolismo , Animales , Pollos , Masculino
13.
Biochem Biophys Res Commun ; 493(4): 1573-1580, 2017 12 02.
Artículo en Inglés | MEDLINE | ID: mdl-28989026

RESUMEN

Myocardial oxidative stress injury plays a crucial role in the pathogenesis of diabetic cardiomyopathy (DCM). Wnt/ß-catenin signaling has been reported to involve in various heart diseases. However, the underlying mechanism associated with ß-catenin in DCM remains elusive. This study intended to explore the effect of ß-catenin on oxidative damage of DCM by establishing streptozotocin (STZ)-induced diabetic mouse model and hydrogen peroxide (H2O2)-treated myocardial cell model. Cardiac oxidative stress in DCM was detected by measurements of lipid peroxidation and anti-oxidative enzyme activities as well as DHE staining. Nuclear ß-catenin activity and oxidative damage degree were measured by western blotting, qPCR, MTT assay and TUNEL staining. Cardiac function and morphology were evaluated by echocardiography and histopathology. Under diabetic oxidative stress or H2O2 stimulation, nuclear ß-catenin accumulation upregulated downstream c-Myc and further facilitated DNA damage and p53-mediated apoptosis as well as cell viability reduction, followed by phenotypic changes of cardiac dysfunction, interstitial fibrosis deposition and myocardial atrophy. Conversely, through directly inhibiting nuclear ß-catenin/c-Myc axis, not only did siRNA knockdown of ß-catenin or c-Myc attenuate cell injury in H2O2-stimulated cardiomyocytes, but also diabetic cardiac-specific ß-catenin-knockout mice displayed the same prevention of heart injury as insulin-treated diabetic mice. The present study demonstrated that activated nuclear ß-catenin/c-Myc axis was responsible for oxidative cardiac impairment of DCM. Therefore, repressing functional nuclear ß-catenin may provide a hopeful therapeutic strategy for DCM.


Asunto(s)
Diabetes Mellitus Experimental/complicaciones , Diabetes Mellitus Experimental/metabolismo , Cardiomiopatías Diabéticas/etiología , Cardiomiopatías Diabéticas/metabolismo , Proteínas Proto-Oncogénicas c-myc/metabolismo , beta Catenina/metabolismo , Animales , Apoptosis , Núcleo Celular/metabolismo , Células Cultivadas , Daño del ADN , Diabetes Mellitus Experimental/patología , Cardiomiopatías Diabéticas/patología , Técnicas de Silenciamiento del Gen , Peróxido de Hidrógeno/toxicidad , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Miocitos Cardíacos/efectos de los fármacos , Miocitos Cardíacos/metabolismo , Estrés Oxidativo , Proteínas Proto-Oncogénicas c-myc/antagonistas & inhibidores , Proteínas Proto-Oncogénicas c-myc/genética , Ratas , Transducción de Señal , beta Catenina/deficiencia , beta Catenina/genética
14.
Plant Biotechnol J ; 14(6): 1470-83, 2016 06.
Artículo en Inglés | MEDLINE | ID: mdl-26801211

RESUMEN

The hyperaccumulating ecotype of Sedum alfredii Hance is a cadmium (Cd)/zinc/lead co-hyperaccumulating species of Crassulaceae. It is a promising phytoremediation candidate accumulating substantial heavy metal ions without obvious signs of poisoning. However, few studies have focused on the regulatory roles of miRNAs and their targets in the hyperaccumulating ecotype of S. alfredii. Here, we combined analyses of the transcriptomics, sRNAs and the degradome to generate a comprehensive resource focused on identifying key regulatory miRNA-target circuits under Cd stress. A total of 87 721 unigenes and 356 miRNAs were identified by deep sequencing, and 79 miRNAs were differentially expressed under Cd stress. Furthermore, 754 target genes of 194 miRNAs were validated by degradome sequencing. A gene ontology (GO) enrichment analysis of differential miRNA targets revealed that auxin, redox-related secondary metabolism and metal transport pathways responded to Cd stress. An integrated analysis uncovered 39 pairs of miRNA targets that displayed negatively correlated expression profiles. Ten miRNA-target pairs also exhibited negative correlations according to a real-time quantitative PCR analysis. Moreover, a coexpression regulatory network was constructed based on profiles of differentially expressed genes. Two hub genes, ARF4 (auxin response factor 4) and AAP3 (amino acid permease 3), which might play central roles in the regulation of Cd-responsive genes, were uncovered. These results suggest that comprehensive analyses of the transcriptomics, sRNAs and the degradome provided a useful platform for investigating Cd hyperaccumulation in S. alfredii, and may provide new insights into the genetic engineering of phytoremediation.


Asunto(s)
Biodegradación Ambiental , Cadmio/metabolismo , Sedum/metabolismo , Transcriptoma/efectos de los fármacos , Transporte Biológico/genética , Cadmio/farmacología , Regulación de la Expresión Génica de las Plantas/efectos de los fármacos , Redes Reguladoras de Genes , MicroARNs/química , Sedum/efectos de los fármacos , Sedum/genética , Análisis de Secuencia de ARN , Transducción de Señal/efectos de los fármacos , Transducción de Señal/genética
15.
Chemistry ; 21(34): 11994-8, 2015 Aug 17.
Artículo en Inglés | MEDLINE | ID: mdl-26177976

RESUMEN

A new highly enantioselective domino Michael/hemiketalization reaction of α-hydroxyacetophenone with ß,γ-unsaturated α-keto esters for the synthesis of 2,2,4,5-tetrasubstituted chiral tetrahydrofurans is reported. With 2 mol % intramolecular dinuclear zinc-AzePhenol complex prepared in situ from the reaction of multidentate semi-azacrown ether ligand with ZnEt2 , the corresponding anti-multisubstituted tetrahydrofuran products were obtained in up to 90 % yields, and 98 % enantiomeric excess (ee) at 0 °C for 45 min. Moreover, the products were easily converted to 2,3,5-trisubstituted 2,3-dihydrofurans without any loss in optical activity.

16.
J Org Chem ; 79(23): 11690-9, 2014 Dec 05.
Artículo en Inglés | MEDLINE | ID: mdl-25392948

RESUMEN

A highly enantioselective Friedel-Crafts (F-C) alkylation of pyrrole with a wide range of simple nonchelating chalcone derivatives catalyzed by a chiral (Zn2EtL)n (L = (S,S)-1) complex has been developed. The catalyst (Zn2EtL)n complex was prepared in situ by reacting the chiral ligand (S,S)-1 with 2 equiv of diethylzinc. A series of ß-pyrrole-substituted dihydrochalcones were usually formed mostly in excellent yields (up to 99%) and excellent enantioselectivity [up to 99% enantiomeric excess (ee)] by using 15 mol % catalyst loading under mild conditions. The absolute stereochemistry of the products was determined to be the S-configuration by X-ray crystallographic analysis of 13g. Meanwhile, a weak negative nonlinear effect was observed. On the basis of the experimental results and previous reports, a possible mechanism was proposed to explain the origin of the asymmetric induction.

17.
J Org Chem ; 79(13): 6087-93, 2014 Jul 03.
Artículo en Inglés | MEDLINE | ID: mdl-24912109

RESUMEN

The diastereomeric aziridine carbinols are applied, respectively, as efficient chiral ligand in the catalysis of asymmetric arylation and sequential arylation-lactonization cascade. The two diastereomers, which are facilely synthesized from the same chiral source, function as pseudo enantiomers in arylation of aromatic aldehydes providing the different enantiomers of the diarylmethanols with almost the same excellent enantioselectivities. The arylation method is also carried out in tandem with lactonization process to afford a concise synthetic approach to both enantiomers of optically active 3-aryl phthalide.


Asunto(s)
Aldehídos/química , Aziridinas/química , Benzofuranos/síntesis química , Benzofuranos/química , Catálisis , Estructura Molecular , Estereoisomerismo
18.
Angew Chem Int Ed Engl ; 53(19): 4940-4, 2014 May 05.
Artículo en Inglés | MEDLINE | ID: mdl-24664928

RESUMEN

An asymmetric two-step approach to chiral bridged tricyclic benzopyrans, core structures featured in various natural products, is described. In the synthesis, an unprecedented enantioselective catalytic decarboxylative Diels-Alder reaction is developed using readily available coumarin-3-carboxylic acids and aldehydes as reactants under mild reaction conditions. Notably, the decarboxylation-assisted release of the catalyst enables the process to proceed efficiently with high enantio- and diastereoselectivity. Furthermore, a one-pot procedure for either a LiAlH4 - or NaBH4 -mediated reduction with subsequent acid-catalyzed intramolecular cyclization of the Diels-Alder adducts was identified for the efficient formation of the chiral bridged tricyclic benzopyrans.

19.
Anal Methods ; 16(15): 2322-2329, 2024 Apr 18.
Artículo en Inglés | MEDLINE | ID: mdl-38533729

RESUMEN

Cysteine is an important amino acid that is related to human health and food safety. How to effectively detect Cys in food has received widespread attention. Compared with other methods, fluorescent probes have the advantages of simple operation, high sensitivity, and good selectivity. Therefore, a selective fluorescence probe 2 for Cys in food was designed and synthesized. Probe 2 employed the acrylate group as a thiol-recognition site for Cys, which endowed probe 2 with better selectivity for Cys over Hcy and GSH. The recognition pathway underwent Michael addition, intramolecular cyclization, and concomitant release of the piperideine-based fluorophore, along with a chromogenic change from yellow to orange. This pathway was supported by 1H NMR analysis and DFT calculations. In addition, probe 2 displays a linear response to Cys concentrations (0-30 µM), low detection limit (0.89 µM), and large Stokes shift (125 nm). Overall, probe 2 showed great application potential for the quantitative determination of Cys in water, milk, cucumber, pear and tomato.


Asunto(s)
Cucumis sativus , Pyrus , Solanum lycopersicum , Humanos , Animales , Cisteína/análisis , Cisteína/química , Cisteína/metabolismo , Cucumis sativus/metabolismo , Colorantes Fluorescentes/química , Pyrus/metabolismo , Colorimetría/métodos , Agua , Leche/química , Leche/metabolismo , Células HeLa
20.
Front Immunol ; 15: 1293706, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38646540

RESUMEN

Major histocompatibility complex Class II (MHCII) proteins initiate and regulate immune responses by presentation of antigenic peptides to CD4+ T-cells and self-restriction. The interactions between MHCII and peptides determine the specificity of the immune response and are crucial in immunotherapy and cancer vaccine design. With the ever-increasing amount of MHCII-peptide binding data available, many computational approaches have been developed for MHCII-peptide interaction prediction over the last decade. There is thus an urgent need to provide an up-to-date overview and assessment of these newly developed computational methods. To benchmark the prediction performance of these methods, we constructed an independent dataset containing binding and non-binding peptides to 20 human MHCII protein allotypes from the Immune Epitope Database, covering DP, DR and DQ alleles. After collecting 11 known predictors up to January 2022, we evaluated those available through a webserver or standalone packages on this independent dataset. The benchmarking results show that MixMHC2pred and NetMHCIIpan-4.1 achieve the best performance among all predictors. In general, newly developed methods perform better than older ones due to the rapid expansion of data on which they are trained and the development of deep learning algorithms. Our manuscript not only draws a full picture of the state-of-art of MHCII-peptide binding prediction, but also guides researchers in the choice among the different predictors. More importantly, it will inspire biomedical researchers in both academia and industry for the future developments in this field.


Asunto(s)
Presentación de Antígeno , Biología Computacional , Antígenos de Histocompatibilidad Clase II , Péptidos , Humanos , Antígenos de Histocompatibilidad Clase II/inmunología , Antígenos de Histocompatibilidad Clase II/metabolismo , Péptidos/inmunología , Biología Computacional/métodos , Unión Proteica , Aprendizaje Profundo , Algoritmos
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA