RESUMO
Membrane proteins that exist in lipid bilayers are not isolated molecular entities. The lipid molecules that surround them play crucial roles in maintaining their full structural and functional integrity. Research directed at investigating these critical lipid-protein interactions is developing rapidly. Advancements in both instrumentation and software, as well as in key biophysical and biochemical techniques, are accelerating the field. In this review, we provide a brief outline of structural techniques used to probe protein-lipid interactions and focus on the molecular aspects of these interactions obtained from native mass spectrometry (native MS). We highlight examples in which lipids have been shown to modulate membrane protein structure and show how native MS has emerged as a complementary technique to X-ray crystallography and cryo-electron microscopy. We conclude with a short perspective on future developments that aim to better understand protein-lipid interactions in the native environment.
Assuntos
Glicerofosfolipídeos/metabolismo , Glicolipídeos/metabolismo , Espectrometria de Massas/métodos , Proteínas de Membrana/metabolismo , Esfingolipídeos/metabolismo , Esteróis/metabolismo , Bactérias/química , Bactérias/metabolismo , Sítios de Ligação , Membrana Celular/química , Membrana Celular/metabolismo , Microscopia Crioeletrônica/instrumentação , Microscopia Crioeletrônica/métodos , Fungos/química , Fungos/metabolismo , Glicerofosfolipídeos/química , Glicolipídeos/química , Espectroscopia de Ressonância Magnética/instrumentação , Espectroscopia de Ressonância Magnética/métodos , Espectrometria de Massas/instrumentação , Proteínas de Membrana/química , Proteínas de Membrana/ultraestrutura , Modelos Moleculares , Ligação Proteica , Conformação Proteica em alfa-Hélice , Conformação Proteica em Folha beta , Domínios e Motivos de Interação entre Proteínas , Esfingolipídeos/química , Esteróis/químicaRESUMO
The Plasmodium falciparum reticulocyte-binding protein homolog 5 (PfRH5) is the leading target for next-generation vaccines against the disease-causing blood-stage of malaria. However, little is known about how human antibodies confer functional immunity against this antigen. We isolated a panel of human monoclonal antibodies (mAbs) against PfRH5 from peripheral blood B cells from vaccinees in the first clinical trial of a PfRH5-based vaccine. We identified a subset of mAbs with neutralizing activity that bind to three distinct sites and another subset of mAbs that are non-functional, or even antagonistic to neutralizing antibodies. We also identify the epitope of a novel group of non-neutralizing antibodies that significantly reduce the speed of red blood cell invasion by the merozoite, thereby potentiating the effect of all neutralizing PfRH5 antibodies as well as synergizing with antibodies targeting other malaria invasion proteins. Our results provide a roadmap for structure-guided vaccine development to maximize antibody efficacy against blood-stage malaria.
Assuntos
Anticorpos Monoclonais/imunologia , Anticorpos Neutralizantes/imunologia , Anticorpos Antiprotozoários/imunologia , Eritrócitos/parasitologia , Vacinas Antimaláricas/imunologia , Malária Falciparum/imunologia , Plasmodium falciparum/imunologia , Adolescente , Adulto , Animais , Sítios de Ligação , Proteínas de Transporte/imunologia , Reações Cruzadas/imunologia , Epitopos/imunologia , Feminino , Células HEK293 , Voluntários Saudáveis , Humanos , Malária Falciparum/parasitologia , Masculino , Merozoítos/fisiologia , Pessoa de Meia-Idade , Plasmodium falciparum/metabolismo , Proteínas de Protozoários/imunologia , Coelhos , Ratos , Ratos Sprague-Dawley , Adulto JovemRESUMO
Protein N-glycosylation is a widespread post-translational modification. The first committed step in this process is catalysed by dolichyl-phosphate N-acetylglucosamine-phosphotransferase DPAGT1 (GPT/E.C. 2.7.8.15). Missense DPAGT1 variants cause congenital myasthenic syndrome and disorders of glycosylation. In addition, naturally-occurring bactericidal nucleoside analogues such as tunicamycin are toxic to eukaryotes due to DPAGT1 inhibition, preventing their clinical use. Our structures of DPAGT1 with the substrate UDP-GlcNAc and tunicamycin reveal substrate binding modes, suggest a mechanism of catalysis, provide an understanding of how mutations modulate activity (thus causing disease) and allow design of non-toxic "lipid-altered" tunicamycins. The structure-tuned activity of these analogues against several bacterial targets allowed the design of potent antibiotics for Mycobacterium tuberculosis, enabling treatment in vitro, in cellulo and in vivo, providing a promising new class of antimicrobial drug.
Assuntos
Antibióticos Antituberculose/farmacologia , Defeitos Congênitos da Glicosilação/metabolismo , Inibidores Enzimáticos/farmacologia , N-Acetilglucosaminiltransferases/química , Animais , Antibióticos Antituberculose/química , Sítios de Ligação , Defeitos Congênitos da Glicosilação/genética , Inibidores Enzimáticos/química , Feminino , Células HEK293 , Células Hep G2 , Humanos , Metabolismo dos Lipídeos , Camundongos , Simulação de Acoplamento Molecular , Mutação , N-Acetilglucosaminiltransferases/antagonistas & inibidores , N-Acetilglucosaminiltransferases/genética , N-Acetilglucosaminiltransferases/metabolismo , Ligação Proteica , Células Sf9 , Spodoptera , Tunicamicina/química , Tunicamicina/farmacologia , Uridina Difosfato Ácido Glucurônico/química , Uridina Difosfato Ácido Glucurônico/metabolismoRESUMO
Membrane protein biogenesis faces the challenge of chaperoning hydrophobic transmembrane helices for faithful membrane insertion. The guided entry of tail-anchored proteins (GET) pathway targets and inserts tail-anchored (TA) proteins into the endoplasmic reticulum (ER) membrane with an insertase (yeast Get1/Get2 or mammalian WRB/CAML) that captures the TA from a cytoplasmic chaperone (Get3 or TRC40, respectively). Here, we present cryo-electron microscopy reconstructions, native mass spectrometry, and structure-based mutagenesis of human WRB/CAML/TRC40 and yeast Get1/Get2/Get3 complexes. Get3 binding to the membrane insertase supports heterotetramer formation, and phosphatidylinositol binding at the heterotetramer interface stabilizes the insertase for efficient TA insertion in vivo. We identify a Get2/CAML cytoplasmic helix that forms a "gating" interaction with Get3/TRC40 important for TA insertion. Structural homology with YidC and the ER membrane protein complex (EMC) implicates an evolutionarily conserved insertion mechanism for divergent substrates utilizing a hydrophilic groove. Thus, we provide a detailed structural and mechanistic framework to understand TA membrane insertion.
Assuntos
Proteínas de Membrana/biossíntese , Proteínas de Membrana/química , Complexos Multiproteicos/metabolismo , Linhagem Celular , Sequência Conservada , Evolução Molecular , Humanos , Proteínas de Membrana/metabolismo , Modelos Moleculares , Fosfatidilinositóis/metabolismo , Ligação Proteica , Multimerização Proteica , Estabilidade Proteica , Estrutura Secundária de Proteína , Saccharomyces cerevisiae/metabolismo , Proteínas de Saccharomyces cerevisiae/metabolismoRESUMO
Micronutrient application has a crucial role in mitigating salinity stress in crop plants. This study was carried out to investigate the effect of zinc (Zn) and boron (B) as foliar applications on fenugreek growth and physiology under salt stress (0 and 120 mM). After 35 days of salt treatments, three levels of zinc (0, 50, and 100 ppm) and two levels of boron (0 and 2 ppm) were applied as a foliar application. Salinity significantly reduced root length (72.7%) and shoot length (33.9%), plant height (36%), leaf area (37%), root fresh weight (48%) and shoot fresh weight (75%), root dry weight (80%) and shoot dry weight (67%), photosynthetic pigments (78%), number of branches (50%), and seeds per pod (56%). Fenugreek's growth and physiology were improved by foliar spray of zinc and boron, which increased the length of the shoot (6%) and root length (2%), fresh root weight (18%), and dry root weight (8%), and chlorophyll a (1%), chlorophyll b (25%), total soluble protein content (3%), shoot calcium (9%) and potassium (5%) contents by significantly decreasing sodium ion (11%) content. Moreover, 100 ppm of Zn and 2 ppm of B enhanced the growth and physiology of fenugreek by reducing the effect of salt stress. Overall, boron and zinc foliar spray is suggested for improvement in fenugreek growth under salinity stress.
Assuntos
Trigonella , Zinco , Boro/metabolismo , Boro/farmacologia , Clorofila A/metabolismo , Estresse Salino , Tensoativos/metabolismo , Tensoativos/farmacologia , Trigonella/metabolismo , Zinco/metabolismo , Zinco/farmacologiaRESUMO
Synthetic fabrics, especially polyester, are a primary source of microplastic fibers (MFs), but there is limited data on their accumulation and dose related health impact in living organisms. This study examined the effects of ingested polyester microfibers (PE-MFs) on hematology, histopathology, and serum biochemistry in albino mice. Mice were given varying doses of PE-MFs (100, 200, 400 and 800 µg/d/mice) for a duration of thirty-five days and a notable decreases in certain hematological parameters such as RBCs, Hb, and platelets, and increases in MCV and MCH was noted at (p < 0.05) thereby indicating possible inflammatory response within the body resulting from ingestion of these MFs. Liver enzymes (ALT, AST, and alkaline phosphatase) and histopathological changes in the liver and gastrointestinal tract also exhibited significant variations, with higher levels seen in the group receiving the highest dose of PE-MFs (800 µg/d/mice). In summary, increased exposure to PE-MFs led to a dose-related impact and notable alterations in histopathological, hematological, and serum biomarkers in albino mice. This study highlights the potential hazards associated with dietary exposure to PE-MFs in mammals and emphasizes the need for further research in this field.
RESUMO
BRCA1 accumulation at DNA damage sites is an important step for its function in the DNA damage response and in DNA repair. BRCA1-BRCT domains bind to proteins containing the phosphorylated serine-proline-x-phenylalanine (pSPxF) motif including Abraxas, Bach1/FancJ, and CtIP. In this study, we demonstrate that ionizing radiation (IR)-induces ATM-dependent phosphorylation of serine 404 (S404) next to the pSPxF motif. Crystal structures of BRCT/Abraxas show that phosphorylation of S404 is important for extensive interactions through the N-terminal sequence outside the pSPxF motif and leads to formation of a stable dimer. Mutation of S404 leads to deficiency in BRCA1 accumulation at DNA damage sites and cellular sensitivity to IR. In addition, two germline mutations of BRCA1 are found to disrupt the dimer interface and dimer formation. Thus, we demonstrate a mechanism involving IR-induced phosphorylation and dimerization of the BRCT/Abraxas complex for regulating Abraxas-mediated recruitment of BRCA1 in response to IR.
Assuntos
Proteína BRCA1/metabolismo , Neoplasias Ósseas/metabolismo , Proteínas de Transporte/metabolismo , Núcleo Celular/metabolismo , Dano ao DNA , Osteossarcoma/metabolismo , Sequência de Aminoácidos , Proteínas Mutadas de Ataxia Telangiectasia/genética , Proteínas Mutadas de Ataxia Telangiectasia/metabolismo , Proteína BRCA1/química , Proteína BRCA1/genética , Neoplasias Ósseas/genética , Neoplasias Ósseas/patologia , Proteínas de Transporte/química , Proteínas de Transporte/genética , Linhagem Celular Tumoral , Núcleo Celular/patologia , Núcleo Celular/efeitos da radiação , Cristalografia por Raios X , Mutação em Linhagem Germinativa , Humanos , Modelos Moleculares , Dados de Sequência Molecular , Osteossarcoma/genética , Osteossarcoma/patologia , Fosforilação , Ligação Proteica , Domínios e Motivos de Interação entre Proteínas , Multimerização Proteica , Interferência de RNA , Serina , TransfecçãoRESUMO
The SARS coronavirus 2 (SARS-CoV-2) is the causative agent of the 2019 coronavirus disease (COVID-19) pandemic that has claimed the lives of 6.9 million people and infected over 765 million. It has become a major worldwide health problem and is also known to cause abnormalities in various systems, including the hematologic system. COVID-19 infection primarily affects the lower respiratory tract and can lead to a cascade of events, including a cytokine storm, intravascular thrombosis, and subsequent complications such as arterial and venous thromboses. COVID-19 can cause thrombocytopenia, lymphopenia, and neutrophilia, which are associated with worse outcomes. Prophylactic anticoagulation is essential to prevent complications and death rates associated with the virus's effect on the coagulation system. It is crucial to recognize these complications early and promptly start therapeutic anticoagulation to improve patient outcomes. While rare, COVID-19-induced disseminated intravascular coagulation (DIC) exhibits some similarities to DIC induced by sepsis. Lactate dehydrogenase (LDH), D-dimer, ferritin, and C-reactive protein (CRP) biomarkers often increase in serious COVID-19 cases and poor prognosis. Understanding the pathophysiology of the disease and identifying risk factors for adverse outcomes is critical for effective management of COVID-19.
RESUMO
Lipopolysaccharide (LPS) transport to the outer membrane (OM) is a crucial step in the biogenesis of microbial surface defenses. Although many features of the translocation mechanism have been elucidated, molecular details of LPS insertion via the LPS transport (Lpt) OM protein LptDE remain elusive. Here, we integrate native MS with hydrogen-deuterium exchange MS and molecular dynamics simulations to investigate the influence of substrate and peptide binding on the conformational dynamics of LptDE. Our data reveal that LPS induces opening of the LptD ß-taco domain, coupled with conformational changes on ß-strands adjacent to the putative lateral exit gate. Conversely, an antimicrobial peptide, thanatin, stabilizes the ß-taco, thereby preventing LPS transport. Our results illustrate that LPS insertion into the OM relies on concerted opening movements of both the ß-barrel and ß-taco domains of LptD, and suggest a means for developing antimicrobial therapeutics targeting this essential process in Gram-negative ESKAPE pathogens.
Assuntos
Proteínas da Membrana Bacteriana Externa/genética , Proteínas da Membrana Bacteriana Externa/metabolismo , Lipopolissacarídeos/metabolismo , Translocação Genética/genética , Antibacterianos/farmacologia , Peptídeos Catiônicos Antimicrobianos/farmacologia , Configuração de Carboidratos , Farmacorresistência Bacteriana/genética , Bactérias Gram-Negativas/efeitos dos fármacos , Bactérias Gram-Negativas/genética , Klebsiella pneumoniae/genética , Klebsiella pneumoniae/metabolismo , Espectrometria de Massas , Modelos Moleculares , Simulação de Dinâmica MolecularRESUMO
Viral diseases are a significant challenge in beekeeping, and recent studies have unveiled a potential link between these diseases and the yellow-legged hornets (Vespa velutina), notorious predators of honey bees. However, it remains unclear whether virus diseases are commonly shared between honey bees and hornets or are merely sporadic cross-species transmission events. To address this knowledge gap, we conducted a study utilizing hornet-keeping practices in Yunnan, Southwest China. Our findings demonstrate that deformed wing virus (DWV-A) and Israeli acute paralysis virus (IAPV) can be transmitted from honey bees to yellow-legged hornets. We detected virus replication in various hornet stages, including pupae with IAPV infections, indicating the similarities between infected hornet and honey bee stages. Furthermore, we observed signs and infection intensities of DWV-A and IAPV comparable to those in honey bees. While different polymorphisms were found in the virus isolates from yellow-legged hornets, the sequences remain similar to honey bee counterparts. While our findings suggest that DWV-A and IAPV behave like common diseases, we observed a natural elimination of the viruses in hornet colonies, with minimal alterations in viral sequences. Consequently, these events appear to be cross-species transmission from honey bees, with yellow-legged hornets acting as potential incidental hosts. Further investigations of virus monitoring in hornets promise valuable insights into the disease ecology of bee-infecting viruses.
Assuntos
Dicistroviridae , Vírus de RNA , Viroses , Vespas , Abelhas , Animais , ChinaRESUMO
The aim of the study was to compare three moulting procedures and their effect on productive performance, egg quality, and antibody response of leghorn hens. For this, a total of 324 laying hens were distributed into three treatment groups having 12 replicates of 9 birds each according to completely randomized design. Treatments consisted of three moulting procedures based on feed and light restriction. The targeted weight at the end of moulting was 1450-1470 g. As soon as the moulting procedure is complete, the comparative analysis of post-moult productive performance (feed intake, egg production, egg weight, egg mass, feed per dozen eggs, feed per kg egg mass, livability), egg quality characteristics (egg weight, egg length and width, shape index, surface area, volume, albumen height, weight, Haugh unit score, yolk width, height, index, egg shell pore number, shell weight, thickness, breaking strength), and antibody response against Newcastle disease and avian influenza (H-9) were evaluated. Birds subjected to moulting procedure 3 (8 days fasting and gradual decrease in light) showed improvement in productive performance, egg geometry and quality traits, and antibody response against Newcastle disease virus. Birds experienced moulting procedure 1 (11 days fasting) had improved feed intake, egg production, and livability. However, birds moulted with procedure 2 (6 days fasting) revealed intermediate result in all the studied parameters. In conclusion, moulting through feed and light restriction with 8 days fasting and gradual reduction in light has potential to improve performance of leghorn hens.
Assuntos
Formação de Anticorpos , Galinhas , Animais , Feminino , Albuminas , Muda , ÓvuloRESUMO
Present study evaluated the effect of lighted incubation on pre- and post-hatch performance of Japanese quail. In a completely randomized design, 1200 eggs were evenly divided into 4 treatments groups having six replicates (each tray was considered as replicate), 50 eggs each. Different dichromatic lights (Green + Red; GR, Green + Blue; GB, and Blue + Red; BR) of 250 lux were provided during incubation for 12 h daily and effects of these lights very evaluated on hatching results and post-hatch growth. After hatch, 600 quail chicks were divided into 4 treatments, 6 replicates, and 25 birds each. Regarding hatching traits, better hatchability was found in the GR group compared to GB, BR, and dark group; while early embryonic mortality was lower in BR, GB, and dark group than GR; mid embryonic mortality was lower in dark group and late embryonic mortality was noted in the GR group than those of other treatment groups. In addition, moisture loss during incubation was minimum in BR and dark groups; however, chick spread was better in the GR group. In terms of growth performance, weight gain was better in the GR group; feed intake in dark, feed conversion ratio in BR, and livability were better in BR and GR group. In morphometrics, keel and shank length were higher in all the colored groups (GB, BR, and GR) whereas body length, wing spread, shank circumference, drumstick length, and circumference were higher in the GR group. Regarding serum chemistry, glucose, albumin, and globulin levels were higher in the GR group. It was concluded that under the experimental conditions, GR light at the prenatal stage to Japanese quail eggs positively influenced hatching performance and post-hatch growth.
Assuntos
Coturnix , Óvulo , Animais , Galinhas , Aumento de PesoRESUMO
The study presents a framework to analyze and detect meddling in real-time network data and identify numerous meddling patterns that may be harmful to various communication means, academic institutes, and other industries. The major challenge was to develop a non-faulty framework to detect meddling (to overcome the traditional ways). With the development of machine learning technology, detecting and stopping the meddling process in the early stages is much easier. In this study, the proposed framework uses numerous data collection and processing techniques and machine learning techniques to train the meddling data and detect anomalies. The proposed framework uses support vector machine (SVM) and K-nearest neighbor (KNN) machine learning algorithms to detect the meddling in a network entangled with blockchain technology to ensure the privacy and protection of models as well as communication data. SVM achieves the highest training detection accuracy (DA) and misclassification rate (MCR) of 99.59% and 0.41%, respectively, and SVM achieves the highest-testing DA and MCR of 99.05% and 0.95%, respectively. The presented framework portrays the best meddling detection results, which are very helpful for various communication and transaction processes.
Assuntos
Blockchain , Algoritmos , Aprendizado de Máquina , Máquina de Vetores de Suporte , TecnologiaRESUMO
Bone tumors, such as osteosarcomas, can occur anywhere in the bones, though they usually occur in the extremities of long bones near metaphyseal growth plates. Osteosarcoma is a malignant lesion caused by a malignant osteoid growing from primitive mesenchymal cells. In most cases, osteosarcoma develops as a solitary lesion within the most rapidly growing areas of the long bones in children. The distal femur, proximal tibia, and proximal humerus are the most frequently affected bones, but virtually any bone can be affected. Early detection can reduce mortality rates. Osteosarcoma's manual detection requires expertise, and it can be tedious. With the assistance of modern technology, medical images can now be analyzed and classified automatically, which enables faster and more efficient data processing. A deep learning-based automatic detection system based on whole slide images (WSIs) is presented in this paper to detect osteosarcoma automatically. Experiments conducted on a large dataset of WSIs yielded up to 99.3% accuracy. This model ensures the privacy and integrity of patient information with the implementation of blockchain technology. Utilizing edge computing and fog computing technologies, the model reduces the load on centralized servers and improves efficiency.
Assuntos
Blockchain , Neoplasias Ósseas , Osteossarcoma , Neoplasias Ósseas/diagnóstico por imagem , Criança , Humanos , Aprendizado de Máquina , Osteossarcoma/diagnóstico por imagem , PrivacidadeRESUMO
Semen traits play the vital role in determining the fertility of a broiler breeder flock; however, it can be influenced by several factors. This experiment was carried out to assess some of these factors affecting the semen. A total of 89 male birds and 960 hens of 20-week-old broiler breeder (2215 g ± 7.5%) were divided into two main groups; one was kept in cages (AIC) and another group was kept on deep litter floor (AIF), while both these groups were subjected to AI. The male birds of aforementioned groups (44 males and 480 females) were further divided into 4 sub-groups (11 males and 120 females) to execute different semen collection frequencies i.e., 2, 3, 4, and 5th days' interval. The impact of time duration between semen collection and insemination on sperm kinematics was monitored. The quantitative and qualitative analysis of semen including sperm concentration and sperm kinematics of the collected semen was conducted through a computer-assisted sperm analyzer (CASA) and ONGO machine (working on the CASA principle). Resultantly, the data revealed that the studied parameters of semen were deteriorated with the progression of age of male birds, while the group of males with standard body weight produced the best semen quantitatively and qualitatively followed by overweight particularly during the post peak phase (46-65 = 20 weeks). Although the 3rd day, semen collection frequency was found better for quality, the higher quantity of semen was achieved when males were being collected at the intervals of 4th and 5th day respectively regardless of housing systems. Significant decline in sperm kinematics was recorded with the progression of semen holding duration at the temperature of poultry farm. Furthermore, the highest contamination of E. coli, Salmonella, and Mycoplasma gallisepticum was recorded in the reproductive tract of hens and semen of the AIF group as compared to AIC. Thus, conclusion can be settled that the semen properties are significantly affected by age, body weight, and semen collection intervals in both housing systems, while sperm kinematics is being disrupted with the progression of holding duration. Although housing systems could affect the semen insignificantly, yet lesser contamination was recorded in semen and in the reproductive tract of hens of AIC.
Assuntos
Galinhas , Sêmen , Animais , Masculino , Feminino , Escherichia coli , Habitação , Espermatozoides , Fertilidade , Peso CorporalRESUMO
Background: Several authors investigated a dosimetric impact of leaf width on radiotherapy plan quality subjectively, and concluded that thinner leaf-width multileaf collimators (MLC) are beneficial because of their better coverage of clinically relevant structures. Study aimed to investigate the dosimetric effect of MLC leaf width on volumetric modulated arc therapy plan quality by objective approach. Materials and methods: Twelve of each prostate and head-and-neck patients were planned for volumetric modulated arc therapy (VMAT) treatments for MLC leaf widths of 4 mm and 10 mm. Three different VMAT schemes single-arc, dual-arc and two combined independent single-arcs were optimized. Dose volume histogram and Isodose distribution were used for quantitative and qualitative comparison of the treatment plan, respectively. Dose-volume-indices of the planning target volume, organs at risk and number of delivered monitor units were compared. The 4 mm leaf width being reference over 10 mm and results were noted as statistically significant if p ≤ 0.05 using student t-test. Results: All VMAT schemes for both tumor sites showed a gain in target coverage, similar organs at risk doses and higher monitor units to be delivered, when changing leaf width from 10 mm to 4 mm. The p-values were significant for majority of head-and-neck dose indices. Conclusion: The thinner-leaf MLCs, owing to their better spatial resolution, result in an overall gain for target coverage, while maintaining permissible doses to the organs at risk.
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Despite being catalytically defective, pseudokinases are typically essential players of cellular signalling, acting as allosteric regulators of their active counterparts. Deregulation of a growing number of pseudokinases has been linked to human diseases, making pseudokinases therapeutic targets of interest. Pseudokinases can be dynamic, adopting specific conformations critical for their allosteric function. Interfering with their allosteric role, with small molecules that would lock pseudokinases in a conformation preventing their productive partner interactions, is an attractive therapeutic strategy to explore. As a well-known allosteric activator of epidermal growth factor receptor family members, and playing a major part in cancer progression, the pseudokinase HER3 is a relevant context in which to address the potential of pseudokinases as drug targets for the development of allosteric inhibitors. In this proof-of-concept study, we developed a multiplex, medium-throughput thermal shift assay screening strategy to assess over 100 000 compounds and identify selective small molecule inhibitors that would trap HER3 in a conformation which is unfavourable for the formation of an active HER2-HER3 heterodimer. As a proof-of-concept compound, AC3573 bound with some specificity to HER3 and abrogated HER2-HER3 complex formation and downstream signalling in cells. Our study highlights the opportunity to identify new molecular mechanisms of action interfering with the biological function of pseudokinases.
Assuntos
Inibidores de Proteínas Quinases , Receptor ErbB-3 , Regulação Alostérica , Animais , Células CHO , Cricetulus , Ensaios de Seleção de Medicamentos Antitumorais , Humanos , Estudo de Prova de Conceito , Ligação Proteica , Inibidores de Proteínas Quinases/química , Inibidores de Proteínas Quinases/farmacologia , Receptor ErbB-2/química , Receptor ErbB-2/genética , Receptor ErbB-2/metabolismo , Receptor ErbB-3/antagonistas & inibidores , Receptor ErbB-3/química , Receptor ErbB-3/genética , Receptor ErbB-3/metabolismoRESUMO
The extracellular protease ADAMTS-7 has been identified as a potential therapeutic target in atherosclerosis and associated diseases such as coronary artery disease (CAD). However, ADAMTS-7 inhibitors have not been reported so far. Screening of inhibitors has been hindered by the lack of a suitable peptide substrate and, consequently, a convenient activity assay. Here we describe the first fluorescence resonance energy transfer (FRET) substrate for ADAMTS-7, ATS7FP7. ATS7FP7 was used to measure inhibition constants for the endogenous ADAMTS-7 inhibitor, TIMP-4, as well as two hydroxamate-based zinc chelating inhibitors. These inhibition constants match well with IC50 values obtained with our SDS-PAGE assay that uses the N-terminal fragment of latent TGF-ß-binding protein 4 (LTBP4S-A) as a substrate. Our novel fluorogenic substrate ATS7FP7 is suitable for high throughput screening of ADAMTS-7 inhibitors, thus accelerating translational studies aiming at inhibition of ADAMTS-7 as a novel treatment for cardiovascular diseases such as atherosclerosis and CAD.
Assuntos
Desenvolvimento de Medicamentos , Corantes Fluorescentes/farmacologia , Inibidores de Proteases/farmacologia , Proteína ADAMTS7/antagonistas & inibidores , Proteína ADAMTS7/metabolismo , Relação Dose-Resposta a Droga , Transferência Ressonante de Energia de Fluorescência , Corantes Fluorescentes/síntese química , Corantes Fluorescentes/química , Humanos , Estrutura Molecular , Inibidores de Proteases/síntese química , Inibidores de Proteases/química , Relação Estrutura-Atividade , Especificidade por SubstratoRESUMO
OBJECTIVE: To evaluate different VMAT planning techniques for a multi-leaf collimator (MLC)providing maximum aperture of 21 × 16 cm². METHODS: A VMAT planning study of nine prostate and nine head-and-neck cancer patients was carried out. The patients were previously treated with Intensity Modulated Radiotherapy (IMRT) technique during 2014-15, at radiation oncology SanBortolo Hospital, Vicenza, Italy. Three VMAT plans for each of prostate and head-and-neck cancer patient were optimized using Pinnacle treatment planning system for 6MV photon beam from ElektaSynergyS®Linac system. Single arc, dual arc and combined two independent-single-arcs were optimized for collimator angle 45°. VMAT treatment planning comparison was made among single-arc dual-arc and combined two independent-single-arcs. The student's t-test (two-sided) with p ≤ 0.05 was applied for significant difference between dose volume indices of plans. RESULTS: All VMAT techniques produced clinically acceptable plans for prostate, while for head-and-neck, DA and ISAs significantly improved target coverage compared to SA. Single arc is sufficient for prostate, while inefficient in case of head-and-neck dose-planning. In spite of having different VMAT optimization approach dual arc and two combined independent-single-arcs provided very similar target coverage, while dual arc improved sparing of organs-at-risk. Similar treatment delivery times were observed for DA and ISAs VMAT techniques. CONCLUSIONS: Single arc is sufficient for prostate, while inefficient in case of head-and-neck dose-planning. Dual arc and two combined independent-single-arcs provided similar PTV coverage, while DA provided better sparing of organs at risk.
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Neoplasias de Cabeça e Pescoço , Radioterapia de Intensidade Modulada , Neoplasias de Cabeça e Pescoço/radioterapia , Humanos , Masculino , Próstata , Dosagem Radioterapêutica , Planejamento da Radioterapia Assistida por ComputadorRESUMO
Light in terms of photo- and scoto-periods is the key ambient factor affecting the physiology of birds through establishing normal biological clock and circadian rhythms. In natural incubation light significantly influences embryonic development, however, at commercial setups eggs are incubated under a dark environment. Presently not a single commercial poultry hatchery is using light during incubation; hence, comprehensive studies are needed to address the industry for considering light as a potential embryonic growth stimulant. In the present study, white Light-emitting diodes (LEDs; 5000 K) were installed in the incubator and 250 lx light intensity was provided for 0, 12, and 24 h per day during the whole incubation period. A total of 900 broiler hatching eggs (Hubbard classic; from 58 weeks old parents) were randomly allocated to 3 treatment groups, having 5 replicates of 60 eggs each, a tray was considered as replicate during incubation and these eggs were incubated under standard incubation protocols. After hatching, a total of 300 chicks were picked and divided into 3 described treatments (0, 12, and 24 h of photo-stimulation to eggs during incubation) having 5 replicates of 20 birds each. The results indicated that incubation of eggs under 12 and 24 h of lighting significantly improved (P ≤ 0.05) hatch window, hatchability % (0.0002), a hatch of fertile % (0.001), and carcass yield % (0.0454). Embryonic mortality, dead germs, and dead in shell embryos were lower in eggs incubated under 12 h light. Significantly better FCR (0.0006), stress susceptibilities such as H/L ratio (0.0227), and physical asymmetry (0.0065) were observed among the birds incubated under 12 h light (P ≤ 0.05). In conclusion, an appropriate light stimuli (12 h) may help to improve hatching traits and post-hatch performance of commercial broiler.