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1.
Cell Rep ; 42(5): 112529, 2023 05 30.
Artigo em Inglês | MEDLINE | ID: mdl-37200193

RESUMO

Male mice lacking the androgen receptor (AR) in pancreatic ß cells exhibit blunted glucose-stimulated insulin secretion (GSIS), leading to hyperglycemia. Testosterone activates an extranuclear AR in ß cells to amplify glucagon-like peptide-1 (GLP-1) insulinotropic action. Here, we examined the architecture of AR targets that regulate GLP-1 insulinotropic action in male ß cells. Testosterone cooperates with GLP-1 to enhance cAMP production at the plasma membrane and endosomes via: (1) increased mitochondrial production of CO2, activating the HCO3--sensitive soluble adenylate cyclase; and (2) increased Gαs recruitment to GLP-1 receptor and AR complexes, activating transmembrane adenylate cyclase. Additionally, testosterone enhances GSIS in human islets via a focal adhesion kinase/SRC/phosphatidylinositol 3-kinase/mammalian target of rapamycin complex 2 actin remodeling cascade. We describe the testosterone-stimulated AR interactome, transcriptome, proteome, and metabolome that contribute to these effects. This study identifies AR genomic and non-genomic actions that enhance GLP-1-stimulated insulin exocytosis in male ß cells.


Assuntos
Células Secretoras de Insulina , Ilhotas Pancreáticas , Masculino , Camundongos , Humanos , Animais , Peptídeo 1 Semelhante ao Glucagon/metabolismo , Células Secretoras de Insulina/metabolismo , Adenilil Ciclases/metabolismo , Receptores Androgênicos/metabolismo , Insulina/metabolismo , Glucose/farmacologia , Glucose/metabolismo , Testosterona , Ilhotas Pancreáticas/metabolismo , Fragmentos de Peptídeos/metabolismo , Mamíferos/metabolismo
2.
Cell Rep ; 42(4): 112394, 2023 04 25.
Artigo em Inglês | MEDLINE | ID: mdl-37058408

RESUMO

The ATP-sensitive K+ (KATP) channel is a key regulator of hormone secretion from pancreatic islet endocrine cells. Using direct measurements of KATP channel activity in pancreatic ß cells and the lesser-studied α cells, from both humans and mice, we provide evidence that a glycolytic metabolon locally controls KATP channels on the plasma membrane. The two ATP-consuming enzymes of upper glycolysis, glucokinase and phosphofructokinase, generate ADP that activates KATP. Substrate channeling of fructose 1,6-bisphosphate through the enzymes of lower glycolysis fuels pyruvate kinase, which directly consumes the ADP made by phosphofructokinase to raise ATP/ADP and close the channel. We further show the presence of a plasma membrane-associated NAD+/NADH cycle whereby lactate dehydrogenase is functionally coupled to glyceraldehyde-3-phosphate dehydrogenase. These studies provide direct electrophysiological evidence of a KATP-controlling glycolytic signaling complex and demonstrate its relevance to islet glucose sensing and excitability.


Assuntos
Membrana Celular , Células Secretoras de Glucagon , Glicólise , Células Secretoras de Insulina , Humanos , Animais , Camundongos , Células Secretoras de Glucagon/metabolismo , Células Secretoras de Insulina/metabolismo , Canais KATP/metabolismo , Técnicas de Patch-Clamp , Eletrofisiologia , Membrana Celular/enzimologia , Membrana Celular/metabolismo , Lactato Desidrogenases/metabolismo , Gliceraldeído-3-Fosfato Desidrogenases/metabolismo , Difosfato de Adenosina/metabolismo , Fosfofrutoquinases/metabolismo
3.
Vet Res Commun ; 47(1): 191-205, 2023 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-35633471

RESUMO

Highly pathogenic avian influenza viruses (HPAIV) have been responsible for causing several severe outbreaks across the world. To protect poultry farms and to prevent the possible spread of new influenza pandemics, vaccines that are both efficacious and low-cost are in high demand. We produced stable, large hemagglutinin H5 oligomers in planta by the specific interaction between S•Tag and S•Protein. H5 oligomers combined via S•Tag::S•Protein interaction in plant crude extracts induced strong humoral immune responses, strong neutralizing antibody responses, and resistance in chickens after challenge with a wild type HPAIV H5 virus strain. In all three parameters, plant crude extracts with H5 oligomers induced better responses than crude extracts containing trimers. The neutralizing antibodies induced by by two-dose and one dose immunization with an adjuvanted crude extract containing H5 oligomer protected vaccinated chickens from two lethal H5N1 virus strains with the efficiency of 92% and 100%, respectively. Following housing vaccinated chickens together with ten non-immunized chickens, only one of these chickens had detectable levels of the H5N1 virus. To facilitate the easy storage of a candidate vaccine, the H5 oligomer crude extracts were mixed with adjuvants and stored for 3.5 and 5.5 months at 4 °C, and chickens were immunized with these crude extracts. All these vaccinated chickens survived after a lethal H5N1 virus challenge. H5 oligomer crude extracts are comparable to commercial vaccines as they also induce strong virus-neutralizing immune responses following the administration of a single dose. The cost-effective production of plant crude extract vaccine candidates and the high stability after long-term storage will enable and encourage the further exploration of this technology for veterinary vaccine development.


Assuntos
Virus da Influenza A Subtipo H5N1 , Vacinas contra Influenza , Influenza Aviária , Animais , Hemaglutininas , Galinhas , Anticorpos Antivirais , Anticorpos Neutralizantes , Vacinação/veterinária
4.
Elife ; 112022 08 23.
Artigo em Inglês | MEDLINE | ID: mdl-35997256

RESUMO

Pyruvate kinase (PK) and the phosphoenolpyruvate (PEP) cycle play key roles in nutrient-stimulated KATP channel closure and insulin secretion. To identify the PK isoforms involved, we generated mice lacking ß-cell PKm1, PKm2, and mitochondrial PEP carboxykinase (PCK2) that generates mitochondrial PEP. Glucose metabolism was found to generate both glycolytic and mitochondrially derived PEP, which triggers KATP closure through local PKm1 and PKm2 signaling at the plasma membrane. Amino acids, which generate mitochondrial PEP without producing glycolytic fructose 1,6-bisphosphate to allosterically activate PKm2, signal through PKm1 to raise ATP/ADP, close KATP channels, and stimulate insulin secretion. Raising cytosolic ATP/ADP with amino acids is insufficient to close KATP channels in the absence of PK activity or PCK2, indicating that KATP channels are primarily regulated by PEP that provides ATP via plasma membrane-associated PK, rather than mitochondrially derived ATP. Following membrane depolarization, the PEP cycle is involved in an 'off-switch' that facilitates KATP channel reopening and Ca2+ extrusion, as shown by PK activation experiments and ß-cell PCK2 deletion, which prolongs Ca2+ oscillations and increases insulin secretion. In conclusion, the differential response of PKm1 and PKm2 to the glycolytic and mitochondrial sources of PEP influences the ß-cell nutrient response, and controls the oscillatory cycle regulating insulin secretion.


Assuntos
Trifosfato de Adenosina , Piruvato Quinase , Difosfato de Adenosina , Trifosfato de Adenosina/metabolismo , Aminoácidos , Animais , Camundongos , Nutrientes , Isoformas de Proteínas , Piruvato Quinase/genética , Piruvato Quinase/metabolismo
5.
Front Vet Sci ; 9: 940395, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35967993

RESUMO

Porcine epidemic diarrhea virus (PEDV) is a serious infectious causative agent in swine, especially in neonatal piglets. PEDV genotype 2 (G2) strains, particularly G2a, were the primary causes of porcine epidemic diarrhea (PED) outbreaks in Vietnam. Here, we produced a plant-based CO-26K-equivalent epitope (COE) variant from a Vietnamese highly virulent PEDV strain belonging to genotype 2a (COE/G2a) and evaluated the protective efficacy of COE/G2a-GCN4pII protein (COE/G2a-pII) in piglets against the highly virulent PEDV G2a strain following passive immunity. The 5-day-old piglets had high levels of PEDV-specific IgG antibodies, COE-IgA specific antibodies, neutralizing antibodies, and IFN-γ responses. After virulent challenge experiments, all of these piglets survived and had normal clinical symptoms, no watery diarrhea in feces, and an increase in their body weight, while all of the negative control piglets died. These results suggest that the COE/G2a-pII protein produced in plants can be developed as a promising vaccine candidate to protect piglets against PEDV G2a infection in Vietnam.

6.
Nanomaterials (Basel) ; 11(6)2021 Jun 17.
Artigo em Inglês | MEDLINE | ID: mdl-34204514

RESUMO

Nanodiamond (ND) has recently emerged as a potential nanomaterial for nanovaccine development. Here, a plant-based haemagglutinin protein (H5.c2) of A/H5N1 virus was conjugated with detonation NDs (DND) of 3.7 nm in diameter (ND4), and high-pressure and high-temperature (HPHT) oxidative NDs of ~40-70 nm (ND40) and ~100-250 nm (ND100) in diameter. Our results revealed that the surface charge, but not the size of NDs, is crucial to the protein conjugation, as well as the in vitro and in vivo behaviors of H5.c2:ND conjugates. Positively charged ND4 does not effectively form stable conjugates with H5.c2, and has no impact on the immunogenicity of the protein both in vitro and in vivo. In contrast, the negatively oxidized NDs (ND40 and ND100) are excellent protein antigen carriers. When compared to free H5.c2, H5.c2:ND40, and H5.c2:ND100 conjugates are highly immunogenic with hemagglutination titers that are both 16 times higher than that of the free H5.c2 protein. Notably, H5.c2:ND40 and H5.c2:ND100 conjugates induce over 3-folds stronger production of both H5.c2-specific-IgG and neutralizing antibodies against A/H5N1 than free H5.c2 in mice. These findings support the innovative strategy of using negatively oxidized ND particles as novel antigen carriers for vaccine development, while also highlighting the importance of particle characterization before use.

7.
Cell Rep ; 34(4): 108690, 2021 01 26.
Artigo em Inglês | MEDLINE | ID: mdl-33503433

RESUMO

Hallmarks of mature ß cells are restricted proliferation and a highly energetic secretory state. Paradoxically, cyclin-dependent kinase 2 (CDK2) is synthesized throughout adulthood, its cytosolic localization raising the likelihood of cell cycle-independent functions. In the absence of any changes in ß cell mass, maturity, or proliferation, genetic deletion of Cdk2 in adult ß cells enhanced insulin secretion from isolated islets and improved glucose tolerance in vivo. At the single ß cell level, CDK2 restricts insulin secretion by increasing KATP conductance, raising the set point for membrane depolarization in response to activation of the phosphoenolpyruvate (PEP) cycle with mitochondrial fuels. In parallel with reduced ß cell recruitment, CDK2 restricts oxidative glucose metabolism while promoting glucose-dependent amplification of insulin secretion. This study provides evidence of essential, non-canonical functions of CDK2 in the secretory pathways of quiescent ß cells.


Assuntos
Linfócitos B/metabolismo , Quinase 2 Dependente de Ciclina/uso terapêutico , Canais KATP/efeitos dos fármacos , Animais , Quinase 2 Dependente de Ciclina/farmacologia , Humanos , Camundongos
8.
J Neuroophthalmol ; 41(4): e759-e760, 2021 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-33449492

RESUMO

ABSTRACT: A 25-year-old male patient visited the ophthalmology clinic because of upper eye lid ptosis in the right eye, binocular double vision, and light sensitivity. He was diagnosed with a complete third nerve palsy caused by a skull base myofibroma, a rare clinical entity that has not been described before in oculomotor nerve palsy.


Assuntos
Miofibroma , Doenças do Nervo Oculomotor , Adulto , Humanos , Masculino , Miofibroma/complicações , Nervo Oculomotor , Doenças do Nervo Oculomotor/diagnóstico , Doenças do Nervo Oculomotor/etiologia , Base do Crânio
9.
Cell Metab ; 32(5): 736-750.e5, 2020 11 03.
Artigo em Inglês | MEDLINE | ID: mdl-33147484

RESUMO

Pancreatic ß cells couple nutrient metabolism with appropriate insulin secretion. Here, we show that pyruvate kinase (PK), which converts ADP and phosphoenolpyruvate (PEP) into ATP and pyruvate, underlies ß cell sensing of both glycolytic and mitochondrial fuels. Plasma membrane-localized PK is sufficient to close KATP channels and initiate calcium influx. Small-molecule PK activators increase the frequency of ATP/ADP and calcium oscillations and potently amplify insulin secretion. PK restricts respiration by cyclically depriving mitochondria of ADP, which accelerates PEP cycling until membrane depolarization restores ADP and oxidative phosphorylation. Our findings support a compartmentalized model of ß cell metabolism in which PK locally generates the ATP/ADP required for insulin secretion. Oscillatory PK activity allows mitochondria to perform synthetic and oxidative functions without any net impact on glucose oxidation. These findings suggest a potential therapeutic route for diabetes based on PK activation that would not be predicted by the current consensus single-state model of ß cell function.


Assuntos
Insulina/metabolismo , Piruvato Quinase/metabolismo , Animais , Linhagem Celular , Humanos , Secreção de Insulina , Masculino , Camundongos , Camundongos Endogâmicos C57BL
10.
Front Immunol ; 11: 2152, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33042128

RESUMO

Porcine epidemic diarrhea virus (PEDV) is a causative agent of a highly infectious disease with a high mortality rate, especially in newborn piglets in Asian countries resulting in serious economic loss. The development of a rapid, safe, effective and cost-efficient vaccine is crucial to protect pigs against PEDV infection. The COE antigen is regarded to be a major target for subunit vaccine development against PEDV infection. The naturally assembled COE protein forms a homotrimeric structure. In the present study, we successfully produced a trimeric COE protein as a native structure by fusion with the C-terminal isoleucine zipper trimerization (GCN4pII) motif in Nicotiana benthamiana, with a high expression level shown via semi-quantified Western blots. Trimeric COE protein was purified via immobilized metal affinity chromatography (IMAC), and its trimeric structure was successfully demonstrated by a cross-linking reaction, and a native PAGE gel. A crude extract containing the COE trimer was used for evaluating immunogenicity in mice. After 1 and 2 booster immunizations, the crude extract containing trimeric COE elicited elevated PEDV-specific humoral responses, as demonstrated by ELISA and Western blot analyses. Notably, a virus-neutralizing antibody assay indicated that the neutralization activities of sera of mice vaccinated with the crude extract containing COE-GCN4pII were similar to those of mice vaccinated with a commercial vaccine. These results suggest that crude extract containing trimeric COE is a promising plant-based subunit vaccine candidate for PEDV prevention.


Assuntos
Infecções por Coronavirus/imunologia , Epitopos/genética , Vírus da Diarreia Epidêmica Suína/fisiologia , Glicoproteína da Espícula de Coronavírus/genética , Doenças dos Suínos/imunologia , Suínos/fisiologia , Vacinas Virais/imunologia , Animais , Anticorpos Neutralizantes/metabolismo , Anticorpos Antivirais/metabolismo , Epitopos/imunologia , Imunização Secundária , Camundongos , Multimerização Proteica , Proteínas Recombinantes de Fusão/genética , Glicoproteína da Espícula de Coronavírus/imunologia
11.
Vaccines (Basel) ; 8(4)2020 Oct 09.
Artigo em Inglês | MEDLINE | ID: mdl-33050224

RESUMO

Since 2003, H5N1 highly pathogenic avian influenza viruses (HPAIV) have not only caused outbreaks in poultry but were also transmitted to humans with high mortality rates. Vaccination is an efficient and economical means of increasing immunity against infections to decrease the shedding of infectious agents in immunized animals and to reduce the probability of further infections. Subunit vaccines from plants are the focus of modern vaccine developments. In this study, plant-made hemagglutinin (H5) trimers were purified from transiently transformed N. benthamiana plants. All chickens immunized with purified H5 trimers were fully protected against the severe HPAIV H5N1 challenge. We further developed a proof-of-principle approach by using disulfide bonds, homoantiparallel peptides or homodimer proteins to combine H5 trimers leading to production of H5 oligomers. Mice vaccinated with crude leaf extracts containing H5 oligomers induced neutralizing antibodies better than those induced by crude leaf extracts containing trimers. As a major result, eleven out of twelve chickens (92%) immunized with adjuvanted H5 oligomer crude extracts were protected from lethal disease while nine out of twelve chickens (75%) vaccinated with adjuvanted H5 trimer crude extracts survived. The solid protective immune response achieved by immunization with crude extracts and the stability of the oligomers form the basis for the development of inexpensive protective veterinary vaccines.

12.
BMC Musculoskelet Disord ; 21(1): 216, 2020 Apr 07.
Artigo em Inglês | MEDLINE | ID: mdl-32264862

RESUMO

BACKGROUND: Multiple epiphyseal dysplasia (MED) is a common skeletal dysplasia that is characterized by variable degrees of epiphyseal abnormality primarily involving the hip and knee joints. Mutations in a gene encoding matrilin-3 (MATN3) have been reported as disease causing of autosomal dominant MED. The current study identified a novel c.572 C > A variant (p.A191D) in exon 2 of MATN3 in a Vietnamese family with MED. CASE PRESENTATION: A standard clinical tests and radiological examination were performed in an 8-year-old Vietnamese girl patient. The clinical examination showed that patient height was under average, with bent lower limbs, limited mobility and dislocation of the joints at both knees. Radiological documentation revealed abnormal cartilage development at the epiphysis of the femur and patella. The patient has a varus deformity of the lower limbs. The patient was diagnosed with autosomal dominant MED using molecular testing in the order of the coding sequences and flanking sequences of five genes: COMP (exons 8-19), MATN3 (exon 2), COL9A2 (exon 3), COL9A3 (exon 3), COL9A1 (exon 8) by Sanger sequencing. A novel heterozygous missense variant (c.572 C > A, p.A191D) in MATN3 was identified in this family, which were not inherited from parents. The p.A191D was predicted and classified as a pathogenic variant. When the two predicted structures of the wild type and mutant matrilin-3 were compared, the p.A191D substitution caused conformational changes near the substitution site, resulting in deformity of the ß-sheet of the single A domain of matrilin- 3. CONCLUSIONS: This is the first Vietnamese MED family attributed to p.A191D matrilin-3 variant, and our clinical, radiological and molecular data suggest that the novel de novo missense variant in MATN3 contributed to MED.


Assuntos
Mutação de Sentido Incorreto , Osteocondrodisplasias/genética , Povo Asiático/genética , Criança , Éxons/genética , Família , Feminino , Humanos , Proteínas Matrilinas/genética , Osteocondrodisplasias/diagnóstico por imagem , Linhagem , Radiografia
13.
Circ J ; 84(2): 136-143, 2020 01 24.
Artigo em Inglês | MEDLINE | ID: mdl-31852863

RESUMO

The Asia-Pacific Society of Cardiology (APSC) high-sensitivity troponin T (hs-TnT) consensus recommendations and rapid algorithm were developed to provide guidance for healthcare professionals in the Asia-Pacific region on assessing patients with suspected acute coronary syndrome (ACS) using a hs-TnT assay. Experts from Asia-Pacific convened in 2 meetings to develop evidence-based consensus recommendations and an algorithm for appropriate use of the hs-TnT assay. The Expert Committee defined a cardiac troponin assay as a high-sensitivity assay if the total imprecision is ≤10% at the 99th percentile of the upper reference limit and measurable concentrations below the 99th percentile are attainable with an assay at a concentration value above the assay's limit of detection for at least 50% of healthy individuals. Recommendations for single-measurement rule-out/rule-in cutoff values, as well as for serial measurements, were also developed. The Expert Committee also adopted similar hs-TnT cutoff values for men and women, recommended serial hs-TnT measurements for special populations, and provided guidance on the use of point-of-care troponin T devices in individuals suspected of ACS. These recommendations should be used in conjunction with all available clinical evidence when making the diagnosis of ACS.


Assuntos
Síndrome Coronariana Aguda/diagnóstico , Serviço Hospitalar de Cardiologia/normas , Cardiologia/normas , Técnicas de Diagnóstico Cardiovascular/normas , Serviço Hospitalar de Emergência/normas , Troponina T/sangue , Síndrome Coronariana Aguda/sangue , Síndrome Coronariana Aguda/terapia , Algoritmos , Biomarcadores/sangue , Consenso , Técnicas de Apoio para a Decisão , Árvores de Decisões , Humanos , Valor Preditivo dos Testes , Prognóstico , Reprodutibilidade dos Testes , Sociedades Médicas , Regulação para Cima
14.
Biomed Rep ; 10(2): 107-112, 2019 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-30719288

RESUMO

Crouzon syndrome is a rare autosomal dominant genetic disorder, which causes the premature fusion of the cranial suture. Fibroblast growth factor receptor 2 (FGFR2) mutations are well-known causatives of Crouzon syndrome. The current study aimed to assess the FGFR2 gene associated with Crouzon syndrome in a Vietnamese family of three generations and to characterize their associated clinical features. The family included in the present study underwent complete clinical examination. A patient was clinically examined and presented with typical features of Crouzon syndrome including craniosynostosis, shallow orbits, ocular proptosis and midface hypoplasia. However the patient had normal hands and feet, a normal hearing ability and normal intelligence. Genomic DNA collected from all family members (except from a 16 week-old-foetus) and 200 unrelated control subjects from the same population was extracted from leukocytes obtained from peripheral blood samples. Genomic DNA was extracted from the 16-week-old foetus via the amniotic fluid of the mother. All coding sequences of FGFR2 were amplified via polymerase chain reaction and directly sequenced. A heterozygous FGFR2 missense mutation (c.1012G>C, p.G338R) in exon 10 was identified in the patient with Crouzon but not in other family members, the 16 week-old-foetus or the controls. This mutation was therefore determined to be the causative agent of Crouzon syndrome. In addition, a novel heterozygous silent mutation (c.1164C>T, p.I388I) in exon 11 of the FGFR2 gene was identified in the patient with Crouzon, his mother and the 16-week-old fetus, but not in other family members. The mutation in exon 10 of FGRF2 was confirmed via restriction-enzyme digestion. The gain of the BsoBI site confirmed the FGFR2 mutation in exon 10 of the patient with Crouzon. This molecular finding may provide useful information to aid clinicians in the diagnosis of Crouzon syndrome and may also aid early prenatal diagnoses.

15.
Int J Cardiovasc Imaging ; 35(2): 207-214, 2019 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-30446919

RESUMO

To assess the procedural performance and 3-years outcomes of unprotected complex bifurcation Left Main (LM) stenting using either Culotte or the novel nano-crush techniques, consisting in the use of two ultra-thin strut stents with a 1-ring stent crushed into the LM. We analysed the records of patients with complex distal/bifurcation LM disease and contraindications and/or refusal of bypass surgery, who from 1 January 2014 to 1 November 2017, received at operators' discretion LM double stenting by means of nano-crush technique using Orsiro (Biotronik Inc, Bulack, Switzerland) or Onyx (Medtronic Inc, Galway, Ireland) stents or Culotte stenting using same stent platforms. Among 65 patients (28 females, mean age 77.2 ± 6.2 years), 32 received nano-crush while 33 patients received Culotte technique. Mean angles between left anterior descending coronary artery and left circumflex was 63.6 ± 21.3°. Post-operative success was achieved in 100% of cases. Nano-crush patients showed lower contrast medium volume and X-ray exposure, shorter fluoroscopy and procedural times compared to Culotte patients group. At a mean follow-up of 27.4 ± 10.8 months, clinical-driven target lesion revascularization, myocardial infarction and cardiovascular death were 0 versus 4/33 (12.1%, p = 0.04), 1/32 (3.1%) versus 6/33 (18.1%, p = 0.03) and 2/32 (6.2%) versus 8/33 (24.2%, p = 0.04) in nano-crush versus Culotte patients, respectively. In this single center study, the nano-crush technique was associated with less use of contrast, less procedural time and less X-ray exposure compared to the culotte technique for the treatment of unprotected left main bifurcation lesions.


Assuntos
Meios de Contraste/administração & dosagem , Doença da Artéria Coronariana/cirurgia , Duração da Cirurgia , Intervenção Coronária Percutânea/instrumentação , Intervenção Coronária Percutânea/métodos , Doses de Radiação , Exposição à Radiação , Radiografia Intervencionista , Stents , Idoso , Idoso de 80 Anos ou mais , Meios de Contraste/efeitos adversos , Angiografia Coronária , Doença da Artéria Coronariana/diagnóstico por imagem , Feminino , Humanos , Masculino , Registros Médicos , Intervenção Coronária Percutânea/efeitos adversos , Desenho de Prótese , Exposição à Radiação/efeitos adversos , Radiografia Intervencionista/efeitos adversos , Fatores de Risco , Fatores de Tempo , Resultado do Tratamento , Ultrassonografia de Intervenção
16.
J Exp Anal Behav ; 110(3): 474-499, 2018 11.
Artigo em Inglês | MEDLINE | ID: mdl-30306566

RESUMO

Resurgence is defined as the recurrence of a previously reinforced and then extinguished target response when reducing or eliminating a more recently reinforced alternative response. In experiments with children and pigeons, we evaluated patterns of resurgence across and within sessions through decreases in reinforcer availability by challenging alternative responding with extinction and progressive-ratio schedules. In Phase 1, we reinforced only target responding. In Phase 2, we extinguished target responding while reinforcing an alternative response. Finally, Phase 3 assessed resurgence by (a) extinguishing alternative responding versus (b) introducing a progressive-ratio schedule of reinforcement for alternative responding. In both children and pigeons, resurgence of target responding occurred in both conditions but generally was greater when assessed during extinction than with progressive ratios. Importantly, within-session patterns of resurgence did not differ between testing with progressive ratios and extinction. Resurgence with progressive ratios tended to be greater with longer durations between reinforcers but we observed similar findings with only simulated reinforcers during extinction testing. Therefore, the present investigation reveals that the events contributing to instances of resurgence remain to be understood, and presents an approach from which to examine variables influencing within-session patterns of resurgence.


Assuntos
Extinção Psicológica , Reforço Psicológico , Animais , Transtorno do Espectro Autista/psicologia , Criança , Pré-Escolar , Columbidae , Condicionamento Operante , Humanos , Masculino , Esquema de Reforço
17.
Dev Cell ; 45(6): 738-752.e6, 2018 06 18.
Artigo em Inglês | MEDLINE | ID: mdl-29920278

RESUMO

Normal cells acquire aggressive behavior by modifying signaling pathways. For instance, alteration of endocytosis profoundly impacts both proliferation and migration during tumorigenesis. Here we investigate the mechanisms that enable the endocytic machinery to coordinate these processes. We show that a membrane curvature-sensing protein, endophilin A3, promotes growth and migration of colon cancer cells through two competing mechanisms: an endocytosis pathway that is required for proliferation and a GTPase regulatory pathway that controls cell motility. EndoA3 stimulates cell migration by binding the Rac GEF TIAM1 leading to activation of small GTPases. Competing interactions of EndoA3 with membrane versus TIAM1 modulate hyperproliferative and metastatic phenotypes. Disruption of EndoA3-membrane interactions stimulates TIAM1 and small GTPases in vitro, and further promotes pro-metastatic phenotypes in vivo. Together, these results uncover a coupling mechanism, by which EndoA3 promotes growth and migration of colon cancers, by linking membrane dynamics to GTPase regulation.


Assuntos
Aciltransferases/metabolismo , Neoplasias do Colo/metabolismo , Proteína 1 Indutora de Invasão e Metástase de Linfoma de Células T/metabolismo , Animais , Carcinogênese/patologia , Linhagem Celular Tumoral , Movimento Celular/fisiologia , Proliferação de Células/fisiologia , Transformação Celular Neoplásica , Neoplasias do Colo/patologia , Endocitose/fisiologia , GTP Fosfo-Hidrolases/metabolismo , Fatores de Troca do Nucleotídeo Guanina/metabolismo , Humanos , Camundongos , Metástase Neoplásica , Transdução de Sinais , Peixe-Zebra , Proteínas rac1 de Ligação ao GTP/metabolismo
18.
J Nanobiotechnology ; 15(1): 69, 2017 Oct 05.
Artigo em Inglês | MEDLINE | ID: mdl-28982373

RESUMO

BACKGROUND: The continuing spread of the newly emerged H7N9 virus among poultry in China, as well as the possibility of human-to-human transmission, has attracted numerous efforts to develop an effective vaccine against H7N9. The use of nanoparticles in vaccinology is inspired by the fact that most pathogens have a dimension within the nano-size range and therefore can be processed efficiently by the immune system, which leads to a potent immune response. Herein, we report a facile approach to increase antigen size to achieve not only fast but also effective responses against the recombinant HA/H7N9 protein via a simple conjugation of the protein onto the surface of nanodiamond particles. RESULTS: In this study, trimeric Haemagglutinin (H7) that is transiently expressed in N. benthamiana was purified using affinity chromatography, and its trimeric state was revealed successfully by the cross-linking reaction. The trimeric H7 solution was subsequently mixed with a nanodiamond suspension in different ratios. The successful conjugation of the trimeric H7 onto the surface of nanodiamond particles was demonstrated by the changes in size and Zeta-potential of the particles before and after protein coating, Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE), and Western-blot analysis. Next, biofunction of the protein-nanodiamond conjugates was screened using a haemagglutination assay. A mixture containing 5 µg of trimeric H7 and 60 µg of nanodiamond corresponds to a ratio of 1:12 (w/w) of agglutinated chicken red blood cells at HA titer of 1024, which is 512-fold higher than the HA titer of free trimeric H7. After the 2nd and 3rd immunization in mice, ELISA and Western blot analyses demonstrated that the physical mixture of trimeric H7 protein and nanodiamond (1:12, w/w) elicited statistically significant stronger H7-specific-IgG response demonstrated by higher amounts of H7N9-specific IgG (over 15.4-fold with P < 0.05 after the second immunization). CONCLUSIONS: These results indicated a potential effect inherent to nanodiamond towards modulating immune systems, which should be further evaluated and broadly applied in nanovaccine development.


Assuntos
Glicoproteínas de Hemaglutininação de Vírus da Influenza/imunologia , Subtipo H7N9 do Vírus da Influenza A/imunologia , Vacinas contra Influenza/imunologia , Nanodiamantes , Infecções por Orthomyxoviridae/prevenção & controle , Animais , Formação de Anticorpos , Feminino , Glicoproteínas de Hemaglutininação de Vírus da Influenza/química , Glicoproteínas de Hemaglutininação de Vírus da Influenza/uso terapêutico , Humanos , Imunoglobulina G/imunologia , Vacinas contra Influenza/química , Vacinas contra Influenza/uso terapêutico , Influenza Humana/imunologia , Influenza Humana/prevenção & controle , Camundongos , Camundongos Endogâmicos BALB C , Nanodiamantes/química , Nanodiamantes/uso terapêutico , Nanodiamantes/ultraestrutura , Infecções por Orthomyxoviridae/imunologia , Proteínas Recombinantes/química , Proteínas Recombinantes/imunologia , Proteínas Recombinantes/uso terapêutico
19.
Vet Res ; 48(1): 53, 2017 09 20.
Artigo em Inglês | MEDLINE | ID: mdl-28931425

RESUMO

Plant-based transient expression is an alternative platform to produce hemagglutinin-based subunit vaccines. This production system provides not only fast and effective response in the context of a pandemic but also enables the supply of big volume vaccines at low cost. Crude plant extracts containing influenza hemagglutinin are considered to use as vaccine sources because of avoidance of related purification steps resulting in low cost production allowing veterinary applications. Highly immunogenic influenza hemagglutinins are urgently required to meet these pre-conditions. Here, we present a new and innovative way to generate functional H5 oligomers from avian flu hemagglutinin in planta by the specific interaction of S·Tag and S·Protein. A S·Tag was fused to H5 trimers and this construct was transiently co-expressed in planta with S·Protein-TPs which was multimerized by disulfide bonds via cysteine residues in tailpiece sequences (TP) of IgM antibody. Multimerized S·Protein-TPs serve as bridges/molecular docks to combine S·Tag-fused hemagglutinin trimers to form very large hemagglutinin H5 oligomers. H5 oligomers in the plant crude extract were highly active in hemagglutination resulting in high titers. Immunization of mice with two doses of plant crude extracts containing H5 oligomers after storage for 1 week at 4 °C caused strong immune responses and induced neutralizing specific humoral immune responses in mice. These results allow for the development of cheap influenza vaccines for veterinary application in future.


Assuntos
Hemaglutininas/metabolismo , Imunidade/imunologia , Virus da Influenza A Subtipo H5N1/imunologia , Vacinas contra Influenza/imunologia , Infecções por Orthomyxoviridae/imunologia , Plantas Geneticamente Modificadas/metabolismo , Agrobacterium/metabolismo , Animais , Anticorpos Neutralizantes/imunologia , Anticorpos Antivirais/imunologia , Hemaglutininas/imunologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Infecções por Orthomyxoviridae/prevenção & controle , Proteínas Recombinantes , /metabolismo
20.
Mol Biol Cell ; 27(13): 2119-32, 2016 07 01.
Artigo em Inglês | MEDLINE | ID: mdl-27170174

RESUMO

Numerous proteins act in concert to sculpt membrane compartments for cell signaling and metabolism. These proteins may act as curvature sensors, membrane benders, and scaffolding molecules. Here we show that endophilin, a critical protein for rapid endocytosis, quickly transforms from a curvature sensor into an active bender upon membrane association. We find that local membrane deformation does not occur until endophilin inserts its amphipathic helices into lipid bilayers, supporting an active bending mechanism through wedging. Our time-course studies show that endophilin continues to drive membrane changes on a seconds-to-minutes time scale, indicating that the duration of endocytosis events constrains the mode of endophilin action. Finally, we find a requirement of coordinated activities between wedging and scaffolding for endophilin to produce stable membrane tubules in vitro and to promote synaptic activity in vivo. Together these data demonstrate that endophilin is a multifaceted molecule that precisely integrates activities of sensing, bending, and stabilizing curvature to sculpt membranes with speed.


Assuntos
Proteínas Adaptadoras de Transdução de Sinal/genética , Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Proteínas Adaptadoras de Transdução de Sinal/fisiologia , Animais , Membrana Celular/metabolismo , Endocitose/genética , Endocitose/fisiologia , Bicamadas Lipídicas/metabolismo , Membranas/metabolismo , Camundongos , Modelos Moleculares , Estrutura Secundária de Proteína , Estrutura Terciária de Proteína , Fatores de Tempo
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