Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 4 de 4
Filtrar
Mais filtros

Base de dados
Tipo de documento
Intervalo de ano de publicação
1.
Nat Commun ; 12(1): 6912, 2021 11 25.
Artigo em Inglês | MEDLINE | ID: mdl-34824278

RESUMO

Despite their limitations, unfractionated heparin (UFH) and bivalirudin remain standard-of-care parenteral anticoagulants for percutaneous coronary intervention (PCI). We discovered novel direct thrombin inhibitors (DTIs) from tick salivary transcriptomes and optimised their pharmacologic activity. The most potent, ultravariegin, inhibits thrombin with a Ki of 4.0 pM, 445-fold better than bivalirudin. Unexpectedly, despite their greater antithrombotic effect, variegin/ultravariegin demonstrated less bleeding, achieving a 3-to-7-fold wider therapeutic index in rodent thrombosis and bleeding models. When used in combination with aspirin and ticagrelor in a porcine model, variegin/ultravariegin reduced stent thrombosis compared with antiplatelet therapy alone but achieved a 5-to-7-fold lower bleeding time than UFH/bivalirudin. Moreover, two antibodies screened from a naïve human antibody library effectively reversed the anticoagulant activity of ultravariegin, demonstrating proof-of-principle for antidote reversal. Variegin and ultravariegin are promising translational candidates for next-generation DTIs that may reduce peri-PCI bleeding in the presence of antiplatelet therapy.


Assuntos
Antitrombinas/farmacologia , Fibrinolíticos/farmacologia , Carrapatos/genética , Carrapatos/metabolismo , Transcriptoma , Amblyomma , Animais , Anticorpos , Anticoagulantes , Antídotos , Aspirina , Desenvolvimento de Medicamentos , Descoberta de Drogas , Feminino , Biblioteca Gênica , Heparina , Hirudinas , Humanos , Masculino , Fragmentos de Peptídeos , Intervenção Coronária Percutânea/métodos , Proteômica , Ratos , Ratos Sprague-Dawley , Proteínas Recombinantes , Suínos , Trombina , Trombose/tratamento farmacológico
2.
Br J Pharmacol ; 176(20): 3899-3923, 2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-31220339

RESUMO

BACKGROUND AND PURPOSE: Depression and anxiety are common causes of disability, and innovative tools and potential pharmacological targets are actively sought for prevention and treatment. Therapeutic strategies targeting the relaxin-3 peptide or its primary endogenous receptor, RXFP3, for the treatment of major depression and anxiety disorders have been limited by a lack of compounds with drug-like properties. We proposed that a hydrocarbon-stapled mimetic of relaxin-3, when administered intranasally, might be uniquely applicable to the treatment of these disorders. EXPERIMENTAL APPROACH: We designed a series of hydrocarbon-stapled relaxin-3 mimetics and identified the most potent compound using in vitro receptor binding and activation assays. Further, we assessed the effect of intranasal delivery of relaxin-3 and the lead stapled mimetic in rat models of anxiety and depression. KEY RESULTS: We developed an i,i+7 stapled relaxin-3 mimetic that manifested a stabilized α-helical structure, proteolytic resistance, and confirmed agonist activity in receptor binding and activation in vitro assays. The stapled peptide agonist enhanced food intake after intracerebral infusion in rats, confirming in vivo activity. We showed that intranasal delivery of the lead i,i+7 stapled peptide or relaxin-3 had orexigenic effects in rats, indicating a potential clinically translatable route of delivery. Further, intranasal administration of the lead i,i+7 stapled peptide exerted anxiolytic and antidepressant-like activity in anxiety- and depression-related behaviour paradigms. CONCLUSIONS AND IMPLICATIONS: Our preclinical findings demonstrate that targeting the relaxin-3/RXFP3 receptor system via intranasal delivery of an i,i+7 stapled relaxin-3 mimetic may represent an effective treatment approach for depression, anxiety, and related neuropsychiatric disorders.


Assuntos
Ansiolíticos/farmacologia , Antidepressivos/farmacologia , Ansiedade/tratamento farmacológico , Depressão/tratamento farmacológico , Receptores Acoplados a Proteínas G/metabolismo , Administração Intranasal , Animais , Ansiolíticos/administração & dosagem , Ansiolíticos/química , Antidepressivos/administração & dosagem , Antidepressivos/química , Células Cultivadas , Relação Dose-Resposta a Droga , Feminino , Células HEK293 , Humanos , Masculino , Modelos Moleculares , Ratos , Ratos Sprague-Dawley , Receptores Acoplados a Proteínas G/administração & dosagem , Receptores Acoplados a Proteínas G/química
3.
Bioanalysis ; 9(9): 693-705, 2017 May.
Artigo em Inglês | MEDLINE | ID: mdl-28488882

RESUMO

AIM: Variegin is an anticoagulant peptide that will be tested in porcine models of percutaneous coronary intervention. We developed three bioanalytical assays for variegin quantitation and utilized these methods to evaluate pharmacokinetics of variegin in pigs. Results & methodology: The LC-MS/MS, thrombin amidolytic and modified thrombin time assays had a quantitation range of 21.6-5541.7, 10.8-5541.7 and 5.4-5541.7 nM in human plasma, respectively. The elimination half-lives obtained using the LC-MS/MS, modified thrombin time and thrombin amidolytic assays were 52.3 ± 4.4, 50.4 ± 5.9 and 67.7 ± 6.3 min, respectively. CONCLUSION: We developed three bioanalytical assays for a novel direct thrombin inhibitor, variegin. The thrombin time assay is optimized for variegin quantitation during future porcine studies and clinical trials.


Assuntos
Antitrombinas/sangue , Cromatografia Líquida/métodos , Proteínas e Peptídeos Salivares/sangue , Espectrometria de Massas em Tandem/métodos , Tempo de Trombina/métodos , Animais , Antitrombinas/farmacologia , Proteínas de Artrópodes , Humanos , Limite de Detecção , Masculino , Proteínas e Peptídeos Salivares/farmacologia , Suínos , Trombina/antagonistas & inibidores , Trombina/metabolismo
4.
PLoS One ; 11(4): e0153770, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27089306

RESUMO

In the present study a major protein has been purified from the venom of Indian Daboia russelii russelii using gel filtration, ion exchange and Rp-HPLC techniques. The purified protein, named daboxin P accounts for ~24% of the total protein of the crude venom and has a molecular mass of 13.597 kDa. It exhibits strong anticoagulant and phospholipase A2 activity but is devoid of any cytotoxic effect on the tested normal or cancerous cell lines. Its primary structure was deduced by N-terminal sequencing and chemical cleavage using Edman degradation and tandem mass spectrometry. It is composed of 121 amino acids with 14 cysteine residues and catalytically active His48 -Asp49 pair. The secondary structure of daboxin P constitutes 42.73% of α-helix and 12.36% of ß-sheet. It is found to be stable at acidic (pH 3.0) and neutral pH (pH 7.0) and has a Tm value of 71.59 ± 0.46°C. Daboxin P exhibits anticoagulant effect under in-vitro and in-vivo conditions. It does not inhibit the catalytic activity of the serine proteases but inhibits the activation of factor X to factor Xa by the tenase complexes both in the presence and absence of phospholipids. It also inhibits the tenase complexes when active site residue (His48) was alkylated suggesting its non-enzymatic mode of anticoagulant activity. Moreover, it also inhibits prothrombinase complex when pre-incubated with factor Xa prior to factor Va addition. Fluorescence emission spectroscopy and affinity chromatography suggest the probable interaction of daboxin P with factor X and factor Xa. Molecular docking analysis reveals the interaction of the Ca+2 binding loop; helix C; anticoagulant region and C-terminal region of daboxin P with the heavy chain of factor Xa. This is the first report of a phospholipase A2 enzyme from Indian viper venom which targets both factor X and factor Xa for its anticoagulant activity.


Assuntos
Anticoagulantes/farmacologia , Coagulação Sanguínea/efeitos dos fármacos , Daboia/fisiologia , Fator X/antagonistas & inibidores , Fator Xa/química , Fosfolipases A2/farmacologia , Venenos de Víboras/enzimologia , Sequência de Aminoácidos , Animais , Testes de Coagulação Sanguínea , Fator X/metabolismo , Fator Xa/metabolismo , Simulação de Acoplamento Molecular , Dados de Sequência Molecular , Fosfolipases A2/química , Fosfolipases A2/isolamento & purificação , Estrutura Secundária de Proteína , Homologia de Sequência de Aminoácidos , Relação Estrutura-Atividade
SELEÇÃO DE REFERÊNCIAS
Detalhe da pesquisa