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1.
Lancet ; 396(10245): 147-148, 2020 07 18.
Artigo em Inglês | MEDLINE | ID: mdl-32682464
2.
S Afr Med J ; 110(2): 106-111, 2020 Jan 29.
Artigo em Inglês | MEDLINE | ID: mdl-32657679

RESUMO

BACKGROUND: Hepatitis C virus (HCV) in South Africa (SA) is incompletely characterised and understood. Epidemiological and clinical data will better inform our understanding and assist national policy decision-making. Against the background of more than two decades of clinical challenges in HCV management, the advent of direct-acting antivirals (DAAs) now makes HCV elimination plausible. OBJECTIVES: To better understand the base from which we come, we elected to review and characterise our HCV experience at Groote Schuur Hospital (GSH), Cape Town, SA, in the pegylated interferon (Peg-IFN) and ribavirin (RBV) management era. METHODS: Patients with chronic HCV infection attending the GSH Liver Clinic from 2002 to 2014 were included in the analysis. Relevant data were extracted from a registry and existing clinical records were accessed. Two brands of Peg-IFN were available, and patients treated with the first-generation add-on protease inhibitor telaprevir were included. RESULTS: A total of 238 patients were included in the analysis (median (interquartile range) 47 (37 - 58) years, 60.5% males). Males were significantly younger than females (43.5 (35 - 52) years v. 55 (42 - 64) years, respectively) (p<0.0001). The majority were white (55.9%) or of mixed ancestry (21.8%), 16.4% were HIV co-infected, 3.7% were hepatitis B virus (HBV) co-infected, and 1 patient (0.4%) was triple-infected with HCV, HBV and HIV. The most likely mode of HCV acquisition was blood or blood product exposure prior to 1992 (32.8%) and injecting drug use (17.6%), while 30.3% of patients had no clear risk factor identifiable. Genotypes (GTs) 1 - 5 were observed, with GT-1 (34.9%) predominating. Of patients who were biopsied (n=90), 30.0% had ≥F3 fibrosis, with 15.6% cirrhotic. With IL28B polymorphisms, the heterozygous CT (23.9%) and CC (15.5%) genotypes were most frequent. Of the patients, 32.6% accessed Peg-IFN/RBV-based therapy, 6.5% (n=5) with add-on telaprevir. GT-1 (35.1%) was most prevalent in the treatment group, followed by GT-3 (26.0%) and GT-5 (18.2%); 10.0% were HIV co-infected. The overall sustained virological response (SVR) rate was 75.3%, with 37.0% of GT-1 patients not achieving SVR. Of the patients treated, 49.4% experienced adverse events, including cytopenias (32.5%) and depression (15.6%), and 23.4% required cell support in the form of erythropoietin and/or granulocyte-macrophage colony-stimulating factor. CONCLUSIONS: HCV patients in the Peg-IFN/RBV management era typified the epidemiology of HCV. GT distribution was pangenotypic, and treatment outcomes were encouraging despite treatment challenges. Patient selection, IL28B and sensible support of cytopenias probably accounted for these favourable outcomes. However, numbers treated were limited, and the DAA era of therapy allows for rapid expansion of therapy with now growing numbers of patients and a changing local epidemiology.


Assuntos
Antivirais/administração & dosagem , Infecções por HIV/epidemiologia , Hepacivirus/genética , Hepatite C Crônica/tratamento farmacológico , Adulto , Antivirais/efeitos adversos , Quimioterapia Combinada , Feminino , Genótipo , Hepacivirus/isolamento & purificação , Hepatite C Crônica/virologia , Humanos , Interferons/administração & dosagem , Masculino , Pessoa de Meia-Idade , Oligopeptídeos/administração & dosagem , Seleção de Pacientes , Polietilenoglicóis/química , Estudos Retrospectivos , Ribavirina/administração & dosagem , África do Sul , Resultado do Tratamento
3.
Endocr Res ; 45(3): 210-215, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32628899

RESUMO

BACKGROUND: Uptake of coronaviruses by target cells involves binding of the virus by cell ectoenzymes. For the etiologic agent of COVID-19 (SARS-CoV-2), a receptor has been identified as angiotensin-converting enzyme-2 (ACE2). Recently it has been suggested that plasma membrane integrins may be involved in the internalization and replication of clinically important coronaviruses. For example, integrin αvß3 is involved in the cell uptake of a model porcine enteric α-coronavirus that causes human epidemics. ACE2 modulates the intracellular signaling generated by integrins. OBJECTIVE: We propose that the cellular internalization of αvß3 applies to uptake of coronaviruses bound to the integrin, and we evaluate the possibility that clinical host T4 may contribute to target cell uptake of coronavirus and to the consequence of cell uptake of the virus. DISCUSSION AND CONCLUSIONS: The viral binding domain of the integrin is near the Arg-Gly-Asp (RGD) peptide-binding site and RGD molecules can affect virus binding. In this same locale on integrin αvß3 is the receptor for thyroid hormone analogues, particularly, L-thyroxine (T4). By binding to the integrin, T4 has been shown to modulate the affinity of the integrin for other proteins, to control internalization of αvß3 and to regulate the expression of a panel of cytokine genes, some of which are components of the 'cytokine storm' of viral infections. If T4 does influence coronavirus uptake by target cells, other thyroid hormone analogues, such as deaminated T4 and deaminated 3,5,3'-triiodo-L-thyronine (T3), are candidate agents to block the virus-relevant actions of T4 at integrin αvß3 and possibly restrict virus uptake.


Assuntos
Infecções por Coronavirus/virologia , Integrina alfaVbeta3/metabolismo , Vírus da Diarreia Epidêmica Suína/metabolismo , Receptores Virais/efeitos dos fármacos , Hormônios Tireóideos/farmacologia , Animais , Betacoronavirus/metabolismo , Sítios de Ligação , Citocinas/fisiologia , Células Epiteliais/virologia , Humanos , Oligopeptídeos/metabolismo , Pandemias , Peptidil Dipeptidase A/metabolismo , Pneumonia Viral/virologia , Receptores Virais/química , Receptores Virais/metabolismo , Suínos , Hormônios Tireóideos/fisiologia , Tiroxina/fisiologia , Internalização do Vírus
4.
Int J Nanomedicine ; 15: 3953-3964, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32581539

RESUMO

Objective: To construct an ideal theranostic nanoplatform (LIP3); to clarify its physicochemical properties; to confirm its characteristics of dual-modality imaging, active-targeting, and cascade amplification therapy for mammary carcinoma; and to perform a preliminary exploration of the cytotoxicity mechanism. Design: A self-prepared liposome nanosystem, LIP3, can actively target 4T1 cells because the surface is linked with C-RGD. Haematoporphyrin monomethyl ether (HMME), an excellent sonosensitizer entrapped in the lipid bilayer, can function in photoacoustic imaging. Low-intensity focused ultrasound (LIFU) of ultrasound-targeted microbubble destruction (UTMD) promotes localized drug delivery into tumours because PFH, a phase-change substance, is loaded in the LIP3 core, achieving visualization of targeted drug release, and sonodynamic therapy (SDT) can kill tumour cells. SDT provides a favourable environment for AQ4N, resulting in amplification of LIP3 treatment. Therefore, LIP3 shows targeted aggregation and targeted release, integrating dual-mode imaging and precise treatment. Results: The self-prepared lipid nanosystem, LIP3, meets the above expectations and has ideal physicochemical properties, with a regular sphere with uniform distribution. Contrast-enhanced ultrasound (CEUS), photoacoustic imaging, and bimodal imaging were effective in vitro. In 4T1 cell experiments, the cell capacity was as high as 42.9%, and the cytotoxicity to 4T1 was more than 5 times that of LIP1 (containing AQ4N only) and more than 2 times that of LIP2 (containing only HMME), achieving comparable results as cascade therapy for mammary cancer. Conclusion: LIP3, a theranostic nanoplatform, was successfully constructed and conformed to the physicochemical characterization of ideal nanoparticles, with active-targeting, dual-modality imaging, visualized drug release, and precise treatment under the action of LIFU. SDT provides a favourable environment for AQ4N, resulting in amplification of LIP3 treatment. Therefore, LIP3 shows targeted aggregation and targeted release, integrating dual-mode imaging, and precise cascade treatment. This unique theranostic NPS with multiple capabilities is expected to be a favourable anti-cancer method in the future.


Assuntos
Neoplasias da Mama/terapia , Nanopartículas/química , Nanomedicina Teranóstica/métodos , Animais , Neoplasias da Mama/diagnóstico por imagem , Linhagem Celular Tumoral , Meios de Contraste/química , Sistemas de Liberação de Medicamentos/métodos , Liberação Controlada de Fármacos , Feminino , Hematoporfirinas/química , Humanos , Lipídeos/química , Lipossomos/química , Camundongos Nus , Nanopartículas/uso terapêutico , Oligopeptídeos/química , Coelhos , Ultrassonografia de Intervenção/métodos
5.
Int J Mol Sci ; 21(10)2020 May 20.
Artigo em Inglês | MEDLINE | ID: mdl-32443911

RESUMO

The COVID-19 global pandemic is caused by SARS-CoV-2, and represents an urgent medical and social issue. Unfortunately, there is still not a single proven effective drug available, and therefore, current therapeutic guidelines recommend supportive care including oxygen administration and treatment with antibiotics. Recently, patients have been also treated with off-label therapies which comprise antiretrovirals, anti-inflammatory compounds, antiparasitic agents and plasma from convalescent patients, all with controversial results. The ubiquitin-proteasome system (UPS) is important for the maintenance of cellular homeostasis, and plays a pivotal role in viral replication processes. In this review, we discuss several aspects of the UPS and the effects of its inhibition with particular regard to the life cycle of the coronaviruses (CoVs). In fact, proteasome inhibition by various chemical compounds, such as MG132, epoxomycin and bortezomib, may reduce the virus entry into the eucariotic cell, the synthesis of RNA, and the subsequent protein expression necessary for CoVs. Importantly, since UPS inhibitors reduce the cytokine storm associated with various inflammatory conditions, it is reasonable to assume that they might be repurposed for SARS-CoV-2, thus providing an additional tool to counteract both virus replication as well as its most deleterious consequences triggered by abnormal immunological response.


Assuntos
Infecções por Coronavirus/tratamento farmacológico , Pneumonia Viral/tratamento farmacológico , Inibidores de Proteassoma/uso terapêutico , Anticorpos Monoclonais/uso terapêutico , Betacoronavirus/efeitos dos fármacos , Betacoronavirus/isolamento & purificação , Infecções por Coronavirus/epidemiologia , Estresse do Retículo Endoplasmático/efeitos dos fármacos , Humanos , Oligopeptídeos/farmacologia , Oligopeptídeos/uso terapêutico , Pandemias , Pneumonia Viral/epidemiologia , Inibidores de Proteassoma/farmacologia
6.
Int J Nanomedicine ; 15: 2717-2732, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32368051

RESUMO

Background: Phototherapy is a potential new candidate for glioblastoma (GBM) treatment. However inadequate phototherapy due to stability of the photosensitizer and low target specificity induces the proliferation of neovascular endothelial cells for angiogenesis and causes poor prognosis. Methods: In this study, we constructed c(RGDfk)-modified glycolipid-like micelles (cRGD-CSOSA) encapsulating indocyanine green (ICG) for dual-targeting neovascular endothelial cells and tumor cells, and cRGD-CSOSA/ICG mediated dual effect of PDT/PTT with NIR irradiation. Results: In vitro, cRGD-CSOSA/ICG inhibited cell proliferation and blocked angiogenesis with NIR irradiation. In vivo, cRGD-CSOSA/ICG exhibited increased accumulation in neovascular endothelial cells and tumor cells. Compared with that of CSOSA, the accumulation of cRGD-CSOSA in tumor tissue was further improved after dual-targeted phototherapy pretreatment. With NIR irradiation, the tumor-inhibition rate of cRGD-CSOSA/ICG was 80.00%, significantly higher than that of ICG (9.08%) and CSOSA/ICG (42.42%). Histological evaluation showed that the tumor vessels were reduced and that the apoptosis of tumor cells increased in the cRGD-CSOSA/ICG group with NIR irradiation. Conclusion: The cRGD-CSOSA/ICG nanoparticle-mediated dual-targeting phototherapy could enhance drug delivery to neovascular endothelial cells and tumor cells for anti-angiogenesis and improve the phototherapy effect of glioblastoma, providing a new strategy for glioblastoma treatment.


Assuntos
Sistemas de Liberação de Medicamentos/métodos , Glioblastoma/terapia , Verde de Indocianina/administração & dosagem , Nanopartículas/administração & dosagem , Neovascularização Patológica/tratamento farmacológico , Fototerapia/métodos , Inibidores da Angiogênese/administração & dosagem , Inibidores da Angiogênese/farmacologia , Animais , Apoptose/efeitos dos fármacos , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Células Endoteliais/efeitos dos fármacos , Glioblastoma/patologia , Glicolipídeos/química , Humanos , Verde de Indocianina/química , Camundongos Nus , Micelas , Nanopartículas/química , Oligopeptídeos/química , Fármacos Fotossensibilizantes/administração & dosagem , Fármacos Fotossensibilizantes/farmacologia , Distribuição Tecidual , Ensaios Antitumorais Modelo de Xenoenxerto
7.
Inflamm Bowel Dis ; 26(8): e89-e91, 2020 07 17.
Artigo em Inglês | MEDLINE | ID: mdl-32440692

RESUMO

Severe Acute Respiratory Syndrome Coronavirus-2 (SAR-CoV-2) has been shown to invade brain tissue. Based on the evolutionary similarity with SARS-CoV, researchers propose that SARS-CoV-2 can invade the olfactory bulb and gastrointestinal (GI) system through angiotensin-converting enzyme 2. However, how SARS-CoV-2 causes neurological or GI symptoms is not clear. Many suggested intestinal and neural inflammations, caused by viral invasion, as the most likely reason for the GI and neurological symptoms; however, the patients with coronavirus disease 2019 (COVID-19) without neurological or GI symptoms indicate that this is not the case. The gut-brain axis could explain the reason for why some with COVID-19 do not have these symptoms. COVID-19 patients mostly show respiratory distress first, then diarrhea, anorexia, stroke, or loss of consciousness comes into view. Obviously, GI invasion is a mechanical process that begins with oral invasion and, therefore, most probably exists before the brain invasion, as indicated in case reports. However, when the GI tract is invaded, the virus may enter the central nervous system through vascular and lymphatic systems or the vagal nerve. SARS-CoV-2 can infect leukocytes and migrate with them into the brain, or the viral particles can be directly transported across the blood-brain barrier to the brain. Also, more recent research has revealed that SARS-CoV-2 can invade the peripheral lymphatic vessels connecting with the glymphatic system of the brain. The temporal correlation between neurological and gastrointestinal symptoms suggests the lymph vessels around the GI tract, the vascular system, or the gut-brain axis (enteric nervous system) as the most likely entry route for SARS-CoV-2 to the brain.


Assuntos
Infecções por Coronavirus/epidemiologia , Sistema Nervoso Entérico/fisiopatologia , Gastroenteropatias/epidemiologia , Doenças do Sistema Nervoso/epidemiologia , Pandemias/estatística & dados numéricos , Pneumonia Viral/epidemiologia , Síndrome Respiratória Aguda Grave/epidemiologia , Comorbidade , Infecções por Coronavirus/diagnóstico , Infecções por Coronavirus/terapia , Feminino , Gastroenteropatias/diagnóstico , Gastroenteropatias/microbiologia , Saúde Global , Humanos , Masculino , Doenças do Sistema Nervoso/diagnóstico , Doenças do Sistema Nervoso/terapia , Neuropeptídeos , Oligopeptídeos , Pneumonia Viral/diagnóstico , Pneumonia Viral/terapia , Prevalência , Medição de Risco , Síndrome Respiratória Aguda Grave/diagnóstico , Síndrome Respiratória Aguda Grave/terapia , Índice de Gravidade de Doença
8.
J Environ Sci (China) ; 93: 129-136, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32446448

RESUMO

Chlorine dioxide (ClO2), an alternative disinfectant to chlorine, has a superior ability to inactivate microorganisms, in which protein damage has been considered as the main inactivation mechanism. However, the reactivity of ClO2 with amino acid residues in oligopeptides and proteins remains poorly investigated. In this research, we studied the reaction rate constants of ClO2 with tryptophan residues in five heptapeptides and four proteins using stopped-flow or competition kinetic method. Each heptapeptide and protein contain only one tryptophan residue and the reactivity of tryptophan residue with ClO2 was lower than that of free tryptophan (3.88 × 104 (mol/L)-1sec-1 at pH 7.0). The neighboring amino acid residues affected the reaction rates through promoting inter-peptide aggregation, changing electron density, shifting pKa values or inducing electron transfer via redox reactions. A single amino acid residue difference in oligopeptides can make the reaction rate constants differ by over 60% (e.g. 3.01 × 104 (mol/L)-1sec-1 for DDDWNDD and 1.85 × 104 (mol/L)-1sec-1 for DDDWDDD at pH 7.0 (D: aspartic acid, W: tryptophan, N: asparagine)). The reaction rates of tryptophan-containing oligopeptides were also highly pH-dependent with higher reactivity for deprotonated tryptophan than the neutral specie. Tryptophan residues in proteins spanned a 4-fold range reactivity toward ClO2 (i.e. 0.84 × 104 (mol/L)-1sec-1 for ribonuclease T1 and 3.21 × 104 (mol/L)-1sec-1 for melittin at pH 7.0) with accessibility to the oxidant as the determinating factor. The local environment surrounding the tryptophan residue in proteins can also accelerate the reaction rates by increasing the electron density of the indole ring of tryptophan or inhibit the reaction rates by inducing electron transfer reactions. The results are of significance in advancing understanding of ClO2 oxidative reactions with proteins and microbial inactivation mechanisms.


Assuntos
Compostos Clorados , Triptofano , Cloro , Oligopeptídeos , Óxidos
9.
Ann Hematol ; 99(6): 1265-1271, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32382772

RESUMO

The incidence and relative risk of kidney toxicity with carfilzomib in multiple myeloma (MM) has been incompletely characterized. We performed a systematic review and meta-analysis of randomized controlled trials (RCTs) comparing carfilzomib-based with non-carfilzomib-based regimens in MM to investigate the risk of kidney toxicity. Point estimates were pooled in the form of risk ratios (RR) with 95% confidence intervals (CI) using the random-effects model. We identified four RCTs with 2954 patients. The median duration of treatment ranged from 16.3 to 88 weeks in carfilzomib arms. The cumulative rate of kidney toxicities in the carfilzomib arms was 21.3% for all grades and 8.3% for grades 3-5 toxicities, with acute kidney injury being the predominantly reported event. Patients receiving a carfilzomib-based regimen had a significantly higher risk of total kidney toxicity compared with those in the control arms, with pooled RR of 1.79 (95% CI, 1.43-2.23, p < 0.001) and 2.29 (95% CI, 1.59-3.30; p < 0.001), for all grades and grades 3-5 toxicities, respectively. Despite adjustment for the duration of exposure in treatment arms, pooled incidence rate ratios (IRR) for kidney toxicity was significantly increased in the carfilzomib arm compared with control (pooled IRR of 1.28 for all grades and 1.66 for grades 3-5 toxicity). Subgroup analysis based on carfilzomib dose, infusion length, and treatment setting did not identify any significant subgroup effect. Kidney toxicity is an important adverse effect of carfilzomib-based regimens. Prospective studies should investigate patient-, disease-, and treatment-related risk factors for severe kidney toxicities and impact on long-term outcome.


Assuntos
Lesão Renal Aguda/induzido quimicamente , Mieloma Múltiplo/tratamento farmacológico , Oligopeptídeos/efeitos adversos , Ensaios Clínicos Controlados Aleatórios como Assunto/métodos , Lesão Renal Aguda/diagnóstico , Lesão Renal Aguda/epidemiologia , Humanos , Mieloma Múltiplo/diagnóstico , Mieloma Múltiplo/epidemiologia , Fatores de Risco
10.
Chemosphere ; 256: 127066, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32434091

RESUMO

Tri(1,3-dichloropropyl) phosphate (TDCPP) potentially damages the thyroid system in humans and animals. However, knowledge of its toxic effects and underlying mechanisms is limited. The present study was conducted to determine the thyroid hormone-disrupting effects of TDCPP and its major metabolite, bis(1,3-dichloro-2-propyl) phosphate (BDCPP) in rat pituitary cell lines (GH3). TDCPP and BDCPP, that mimic the thyroid hormone (TH), promoted GH3 cell proliferation and modulated the progression of the cell cycle at 20 and 200 µmol/L, respectively. Similar to T3, TDCPP and BDCPP also significantly upregulated c-fos and downregulated Tshß gene expression. Although the binding affinity of these chemicals for thyroid receptor ß (TRß) was not measured, significant competition between these chemicals to bind to the membrane thyroid hormone receptor (integrin αvß3) was found, suggesting that TDCPP and BDCPP were strongly bound to integrin αvß3. Results from a molecular docking analysis provided further evidence of strong binding affinities of TDCPP and BDCPP for integrin αvß3, and the ligand binding site of Arg-Gly-Asp (RGD) was identified. Real-time PCR also supported the supposition that, after binding to integrin αvß3, TDCPP and BDCPP may induce the activation of the extracellular signal-regulated protein kinase (ERK1/2) signal transduction pathway. Taken together, our data suggest that TDCPP and BDCPP have the ability to mimic THs and that the underlying mechanism might be associated with their interactions with integrin αvß3 and the activation of the ERK1/2 pathway, providing new insight into the mechanism of TDCPP- and BDCPP-induced cytotoxicity.


Assuntos
Organofosfatos/toxicidade , Hormônios Tireóideos/metabolismo , Testes de Toxicidade , Animais , Proliferação de Células/efeitos dos fármacos , MAP Quinases Reguladas por Sinal Extracelular/metabolismo , Humanos , Integrina alfaVbeta3/metabolismo , Sistema de Sinalização das MAP Quinases/efeitos dos fármacos , Proteína Quinase 3 Ativada por Mitógeno , Simulação de Acoplamento Molecular , Oligopeptídeos , Organofosfatos/metabolismo , Compostos Organofosforados , Ratos , Transdução de Sinais , Glândula Tireoide/efeitos dos fármacos
11.
J Chem Inf Model ; 60(6): 3277-3286, 2020 06 22.
Artigo em Inglês | MEDLINE | ID: mdl-32315171

RESUMO

The recent outbreak of novel coronavirus disease-19 (COVID-19) calls for and welcomes possible treatment strategies using drugs on the market. It is very efficient to apply computer-aided drug design techniques to quickly identify promising drug repurposing candidates, especially after the detailed 3D structures of key viral proteins are resolved. The virus causing COVID-19 is SARS-CoV-2. Taking advantage of a recently released crystal structure of SARS-CoV-2 main protease in complex with a covalently bonded inhibitor, N3 (Liu et al., 10.2210/pdb6LU7/pdb), I conducted virtual docking screening of approved drugs and drug candidates in clinical trials. For the top docking hits, I then performed molecular dynamics simulations followed by binding free energy calculations using an end point method called MM-PBSA-WSAS (molecular mechanics/Poisson-Boltzmann surface area/weighted solvent-accessible surface area; Wang, Chem. Rev. 2019, 119, 9478; Wang, Curr. Comput.-Aided Drug Des. 2006, 2, 287; Wang; ; Hou J. Chem. Inf. Model., 2012, 52, 1199). Several promising known drugs stand out as potential inhibitors of SARS-CoV-2 main protease, including carfilzomib, eravacycline, valrubicin, lopinavir, and elbasvir. Carfilzomib, an approved anticancer drug acting as a proteasome inhibitor, has the best MM-PBSA-WSAS binding free energy, -13.8 kcal/mol. The second-best repurposing drug candidate, eravacycline, is synthetic halogenated tetracycline class antibiotic. Streptomycin, another antibiotic and a charged molecule, also demonstrates some inhibitory effect, even though the predicted binding free energy of the charged form (-3.8 kcal/mol) is not nearly as low as that of the neutral form (-7.9 kcal/mol). One bioactive, PubChem 23727975, has a binding free energy of -12.9 kcal/mol. Detailed receptor-ligand interactions were analyzed and hot spots for the receptor-ligand binding were identified. I found that one hot spot residue, His41, is a conserved residue across many viruses including SARS-CoV, SARS-CoV-2, MERS-CoV, and hepatitis C virus (HCV). The findings of this study can facilitate rational drug design targeting the SARS-CoV-2 main protease.


Assuntos
Betacoronavirus/efeitos dos fármacos , Infecções por Coronavirus/tratamento farmacológico , Reposicionamento de Medicamentos/métodos , Pneumonia Viral/tratamento farmacológico , Inibidores de Proteases/farmacologia , Proteínas não Estruturais Virais/antagonistas & inibidores , Antibacterianos/química , Antibacterianos/farmacologia , Betacoronavirus/química , Betacoronavirus/enzimologia , Infecções por Coronavirus/virologia , Cisteína Endopeptidases/química , Cisteína Endopeptidases/metabolismo , Reposicionamento de Medicamentos/economia , Humanos , Simulação de Acoplamento Molecular , Simulação de Dinâmica Molecular , Oligopeptídeos/química , Oligopeptídeos/farmacologia , Pandemias , Pneumonia Viral/virologia , Inibidores de Proteases/química , Tetraciclinas/química , Tetraciclinas/farmacologia , Termodinâmica , Fatores de Tempo , Proteínas não Estruturais Virais/química , Proteínas não Estruturais Virais/metabolismo
12.
Nat Commun ; 11(1): 1931, 2020 04 22.
Artigo em Inglês | MEDLINE | ID: mdl-32321912

RESUMO

Enhancing the efficacy of proteasome inhibitors (PI) is a central goal in myeloma therapy. We proposed that signaling-level responses after PI may reveal new mechanisms of action that can be therapeutically exploited. Unbiased phosphoproteomics after treatment with the PI carfilzomib surprisingly demonstrates the most prominent phosphorylation changes on splicing related proteins. Spliceosome modulation is invisible to RNA or protein abundance alone. Transcriptome analysis after PI demonstrates broad-scale intron retention, suggestive of spliceosome interference, as well as specific alternative splicing of protein homeostasis machinery components. These findings lead us to evaluate direct spliceosome inhibition in myeloma, which synergizes with carfilzomib and shows potent anti-tumor activity. Functional genomics and exome sequencing further support the spliceosome as a specific vulnerability in myeloma. Our results propose splicing interference as an unrecognized modality of PI mechanism, reveal additional modes of spliceosome modulation, and suggest spliceosome targeting as a promising therapeutic strategy in myeloma.


Assuntos
Mieloma Múltiplo/tratamento farmacológico , Inibidores de Proteassoma/administração & dosagem , Spliceossomos/efeitos dos fármacos , Animais , Antineoplásicos/administração & dosagem , Feminino , Humanos , Camundongos , Mieloma Múltiplo/genética , Mieloma Múltiplo/metabolismo , Oligopeptídeos/administração & dosagem , Processamento de RNA/efeitos dos fármacos , Spliceossomos/genética , Spliceossomos/metabolismo , Spliceossomos/microbiologia
13.
Clin Immunol ; 215: 108426, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-32311462

Assuntos
Betacoronavirus/imunologia , Infecções por Coronavirus/imunologia , Pneumocystis carinii/imunologia , Pneumonia por Pneumocystis/imunologia , Pneumonia Viral/imunologia , Proteínas Associadas a Surfactantes Pulmonares/química , Surfactantes Pulmonares/química , Glicoproteína da Espícula de Coronavírus/química , Sequência de Aminoácidos , Anticorpos Antivirais/química , Anticorpos Antivirais/genética , Betacoronavirus/patogenicidade , Coronavirus Humano 229E/imunologia , Infecções por Coronavirus/genética , Infecções por Coronavirus/patologia , Infecções por Coronavirus/virologia , Coronavirus Humano OC43/imunologia , Reações Cruzadas , Epitopos/química , Epitopos/genética , Epitopos/imunologia , Expressão Gênica , Interações Hospedeiro-Patógeno/genética , Interações Hospedeiro-Patógeno/imunologia , Humanos , Oligopeptídeos/química , Oligopeptídeos/genética , Oligopeptídeos/imunologia , Pandemias , Pneumocystis carinii/patogenicidade , Pneumonia por Pneumocystis/genética , Pneumonia por Pneumocystis/patologia , Pneumonia por Pneumocystis/virologia , Pneumonia Viral/genética , Pneumonia Viral/patologia , Pneumonia Viral/virologia , Ligação Proteica , Proteínas Associadas a Surfactantes Pulmonares/genética , Proteínas Associadas a Surfactantes Pulmonares/imunologia , Surfactantes Pulmonares/imunologia , Surfactantes Pulmonares/metabolismo , Homologia de Sequência de Aminoácidos , Glicoproteína da Espícula de Coronavírus/genética , Glicoproteína da Espícula de Coronavírus/imunologia
14.
Proc Natl Acad Sci U S A ; 117(15): 8468-8475, 2020 04 14.
Artigo em Inglês | MEDLINE | ID: mdl-32234780

RESUMO

The necroptosis cell death pathway has been implicated in host defense and in the pathology of inflammatory diseases. While phosphorylation of the necroptotic effector pseudokinase Mixed Lineage Kinase Domain-Like (MLKL) by the upstream protein kinase RIPK3 is a hallmark of pathway activation, the precise checkpoints in necroptosis signaling are still unclear. Here we have developed monobodies, synthetic binding proteins, that bind the N-terminal four-helix bundle (4HB) "killer" domain and neighboring first brace helix of human MLKL with nanomolar affinity. When expressed as genetically encoded reagents in cells, these monobodies potently block necroptotic cell death. However, they did not prevent MLKL recruitment to the "necrosome" and phosphorylation by RIPK3, nor the assembly of MLKL into oligomers, but did block MLKL translocation to membranes where activated MLKL normally disrupts membranes to kill cells. An X-ray crystal structure revealed a monobody-binding site centered on the α4 helix of the MLKL 4HB domain, which mutational analyses showed was crucial for reconstitution of necroptosis signaling. These data implicate the α4 helix of its 4HB domain as a crucial site for recruitment of adaptor proteins that mediate membrane translocation, distinct from known phospholipid binding sites.


Assuntos
Materiais Biomiméticos/farmacologia , Membrana Celular/metabolismo , Domínio de Fibronectina Tipo III , Necrose , Oligopeptídeos/farmacologia , Proteínas Quinases/metabolismo , Proteína Serina-Treonina Quinases de Interação com Receptores/metabolismo , Cristalografia por Raios X , Humanos , Fosforilação , Conformação Proteica , Proteínas Quinases/química , Multimerização Proteica , Transporte Proteico
15.
Clin Sci (Lond) ; 134(7): 853-869, 2020 04 17.
Artigo em Inglês | MEDLINE | ID: mdl-32227122

RESUMO

Angiotensin II (Ang II) has been reported to aggravate hepatic fibrosis by inducing NADPH oxidase (NOX)-dependent oxidative stress. Alamandine (ALA) protects against fibrosis by counteracting Ang II via the MAS-related G-protein coupled (MrgD) receptor, though the effects of alamandine on hepatic fibrosis remain unknown. Autophagy activated by reactive oxygen species (ROS) is a novel mechanism of hepatic fibrosis. However, whether autophagy is involved in the regulation of Ang II-induced hepatic fibrosis still requires investigation. We explored the effect of alamandine on hepatic fibrosis via regulation of autophagy by redox balance modulation. In vivo, alamandine reduced CCl4-induced hepatic fibrosis, hydrogen peroxide (H2O2) content, protein levels of NOX4 and autophagy impairment. In vitro, Ang II treatment elevated NOX4 protein expression and ROS production along with up-regulation of the angiotensin converting enzyme (ACE)/Ang II/Ang II type 1 receptor (AT1R) axis. These changes resulted in the accumulation of impaired autophagosomes in hepatic stellate cells (HSCs). Treatment with NOX4 inhibitor VAS2870, ROS scavenger N-acetylcysteine (NAC), and NOX4 small interfering RNA (siRNA) inhibited Ang II-induced autophagy and collagen synthesis. Alamandine shifted the balance of renin-angiotensin system (RAS) toward the angiotensin converting enzyme 2 (ACE2)/alamandine/MrgD axis, and inhibited both Ang II-induced ROS and autophagy activation, leading to attenuation of HSCs migration or collagen synthesis. In summary, alamandine attenuated liver fibrosis by regulating autophagy induced by NOX4-dependent ROS.


Assuntos
Antioxidantes/farmacologia , Autofagia/efeitos dos fármacos , Doença Hepática Induzida por Substâncias e Drogas/prevenção & controle , Células Estreladas do Fígado/efeitos dos fármacos , Peróxido de Hidrogênio/metabolismo , Cirrose Hepática Experimental/prevenção & controle , Fígado/efeitos dos fármacos , NADPH Oxidase 4/metabolismo , Oligopeptídeos/farmacologia , Animais , Tetracloreto de Carbono , Células Cultivadas , Doença Hepática Induzida por Substâncias e Drogas/enzimologia , Doença Hepática Induzida por Substâncias e Drogas/etiologia , Doença Hepática Induzida por Substâncias e Drogas/patologia , Colágeno/metabolismo , Células Estreladas do Fígado/enzimologia , Células Estreladas do Fígado/ultraestrutura , Fígado/enzimologia , Fígado/ultraestrutura , Cirrose Hepática Experimental/induzido quimicamente , Cirrose Hepática Experimental/enzimologia , Cirrose Hepática Experimental/patologia , Masculino , Proteínas do Tecido Nervoso/efeitos dos fármacos , Proteínas do Tecido Nervoso/metabolismo , Estresse Oxidativo/efeitos dos fármacos , Peptidil Dipeptidase A/metabolismo , Ratos Sprague-Dawley , Receptores Acoplados a Proteínas-G/efeitos dos fármacos , Receptores Acoplados a Proteínas-G/metabolismo , Sistema Renina-Angiotensina/efeitos dos fármacos , Transdução de Sinais
16.
Water Res ; 177: 115803, 2020 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-32302809

RESUMO

Previous studies have focused on investigating the formation of odorous by-products during the chlorination of free amino acids (AAs). However, studies on the formation of odorous by-products during the chlorination of combined AAs, which are much more abundant in natural waters than free AAs, are very limited. In this study, the generation of odorous aldehyde, nitrile and N-chloroaldimine from short oligopeptides containing combined Leucine (Leu) (a typical precursor of odorous by-products), including glycylleucine (Gly-Leu), leucylglycine (Leu-Gly), and trileucine (Leu-Leu-Leu), was investigated. The reaction mechanisms were then proposed based on Acquity UPLC-qTOF mass spectrometer measurement and kinetic studies modelled with Kintecus. The results indicated that a series of sequential reactions, including substitution, dehydrohalogenation, ß-elimination, hydrolysis and decarboxylation reactions, occurred during the chlorination of short oligopeptides. The chlorination of Gly-Leu and Leu-Leu-Leu formed free Leu, which continued to react with chlorine, producing isovaleraldehyde, isovaleronitrile and N-chloroisovaleraldimine. Compared with Gly-Leu, Leu-Leu-Leu produced less free Leu, and therefore, a smaller amount of Leu-derived odorous by-products was generated. Leu-Gly produced free Gly, which was not a precursor of odorous by-products. Thus, neither isovaleraldehyde nor N-chloroisovaleraldimine was formed. Notably, isovaleronitriles can be formed directly from a ß-elimination reaction during chlorination of Leu-Gly and Leu-Leu-Leu, and thus high yields of isovaleronitriles were observed after chlorination. The yields of odorous by-products during chlorination of short oligopeptides increased with increasing Cl/N ratios (the molar ratio of chlorine to nitrogen in the AAs) and reached their maximum at Cl/N = 2.4, except the yield of isovaleraldehyde formed from Gly-Leu reached its maximum at Cl/N = 1.6. UV and UV/H2O2 pre-treatments decreased odorous by-product formation during subsequent chlorination through non-peptide bond breaking of short oligopeptides. This study facilitates the identification of the causes of off-flavour problems in drinking water and the development of ways to control these problems.


Assuntos
Desinfetantes , Poluentes Químicos da Água , Purificação da Água , Aldeídos , Cloro , Desinfecção , Halogenação , Peróxido de Hidrogênio , Cinética , Leucina , Nitrilos , Oligopeptídeos
18.
PLoS One ; 15(3): e0230282, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32160243

RESUMO

Cloning and expression of a desired gene is indispensable in molecular biology studies. Expression vectors, in this regard, should offer much needed flexibility and choice of cloning strategies for both in vivo and in vitro protein expression experiments. Furthermore, availability of option to choose from various reporter tags allows one to be flexible during designing of an experiment in a more relevant manner. Thus, the need of a versatile expression system cannot be ignored. Although several different expression vectors are available for gene expression in mycobacteria, they lack the required versatility of expression and the inclusion of reporter tags. We here present the construction of a set of nine E. coli-Mycobacterium shuttle plasmids, which offer a combination of three mycobacterial promoter systems (heat shock inducible-hsp60, tetracycline-, and acetamide-inducible) along with three polypeptide tags (Green Fluorescent Protein (GFP), Glutathione S-transferase (GST) and hexa-histidine tag). These vectors offer the cloning of a target gene in all the nine given vectors in parallel, thus allowing the generation of recombinant plasmids that will express the target gene from different promoters with different tags. Here, while the hexa-histidine and GST tags can be used for protein purification and pull-down experiments, the GFP-tag can be used for protein localization within the cell. Additionally, the vectors also offer the choice of positioning of the reporter tag either at the N-terminus or at the C-terminus of the expressed protein, which is achieved by cloning of the gene at any of the two blunt-end restriction enzyme sites available in the vector. We believe that these plasmids will be extremely useful in the gene expression studies in mycobacteria by offering the choices of promoters and reporters. Our work also paves the way to developing more such plasmids with other tags and promoters that may find use in mycobacterial biology.


Assuntos
Engenharia Genética/métodos , Vetores Genéticos/genética , Mycobacterium/genética , Escherichia coli/genética , Genes Reporter , Glutationa Transferase/genética , Glutationa Transferase/metabolismo , Proteínas de Fluorescência Verde/genética , Proteínas de Fluorescência Verde/metabolismo , Histidina/genética , Histidina/metabolismo , Oligopeptídeos/genética , Oligopeptídeos/metabolismo , Regiões Promotoras Genéticas , Ativação Transcricional
19.
Nature ; 579(7799): 421-426, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-32188939

RESUMO

Bioorthogonal chemistry capable of operating in live animals is needed to investigate biological processes such as cell death and immunity. Recent studies have identified a gasdermin family of pore-forming proteins that executes inflammasome-dependent and -independent pyroptosis1-5. Pyroptosis is proinflammatory, but its effect on antitumour immunity is unknown. Here we establish a bioorthogonal chemical system, in which a cancer-imaging probe phenylalanine trifluoroborate (Phe-BF3) that can enter cells desilylates and 'cleaves' a designed linker that contains a silyl ether. This system enabled the controlled release of a drug from an antibody-drug conjugate in mice. When combined with nanoparticle-mediated delivery, desilylation catalysed by Phe-BF3 could release a client protein-including an active gasdermin-from a nanoparticle conjugate, selectively into tumour cells in mice. We applied this bioorthogonal system to gasdermin, which revealed that pyroptosis of less than 15% of tumour cells was sufficient to clear the entire 4T1 mammary tumour graft. The tumour regression was absent in immune-deficient mice or upon T cell depletion, and was correlated with augmented antitumour immune responses. The injection of a reduced, ineffective dose of nanoparticle-conjugated gasdermin along with Phe-BF3 sensitized 4T1 tumours to anti-PD1 therapy. Our bioorthogonal system based on Phe-BF3 desilylation is therefore a powerful tool for chemical biology; our application of this system suggests that pyroptosis-induced inflammation triggers robust antitumour immunity and can synergize with checkpoint blockade.


Assuntos
Preparações de Ação Retardada/administração & dosagem , Neoplasias Mamárias Experimentais/imunologia , Piroptose/imunologia , Animais , Cumarínicos/administração & dosagem , Cumarínicos/química , Cumarínicos/metabolismo , Cumarínicos/farmacocinética , Preparações de Ação Retardada/química , Preparações de Ação Retardada/metabolismo , Preparações de Ação Retardada/farmacocinética , Feminino , Proteínas de Fluorescência Verde/administração & dosagem , Proteínas de Fluorescência Verde/química , Proteínas de Fluorescência Verde/metabolismo , Proteínas de Fluorescência Verde/farmacocinética , Células HeLa , Humanos , Imunoconjugados/administração & dosagem , Imunoconjugados/química , Imunoconjugados/metabolismo , Imunoconjugados/farmacocinética , Inflamassomos/imunologia , Inflamação/imunologia , Inflamação/metabolismo , Inflamação/patologia , Neoplasias Mamárias Experimentais/metabolismo , Neoplasias Mamárias Experimentais/patologia , Camundongos , Camundongos Endogâmicos BALB C , Oligopeptídeos/administração & dosagem , Oligopeptídeos/química , Oligopeptídeos/metabolismo , Oligopeptídeos/farmacocinética , Receptor de Morte Celular Programada 1/antagonistas & inibidores , Proteínas/administração & dosagem , Proteínas/química , Proteínas/metabolismo , Proteínas/farmacocinética , Silanos/administração & dosagem , Silanos/química , Silanos/metabolismo , Silanos/farmacocinética , Linfócitos T/imunologia , Trastuzumab/administração & dosagem , Trastuzumab/química , Trastuzumab/metabolismo , Trastuzumab/farmacocinética , Ensaios Antitumorais Modelo de Xenoenxerto
20.
Am J Physiol Renal Physiol ; 318(5): F1067-F1073, 2020 05 01.
Artigo em Inglês | MEDLINE | ID: mdl-32200667

RESUMO

Protease-activated receptors (PARs) are coagulation protease targets, and they increase expression of inflammatory cytokines and chemokines in various diseases. Of all PARs, previous reports have shown that PAR1 or PAR2 inhibition is protective against diabetic glomerular injury. However, how PAR1 and PAR2 cooperatively contribute to diabetic kidney disease (DKD) pathogenesis and whether dual blockade of PARs is more effective in DKD remain elusive. To address this issue, male type I diabetic Akita mice heterozygous for endothelial nitric oxide synthase were used as a model of DKD. Mice (4 mo old) were divided into four treatment groups and administered vehicle, PAR1 antagonist (E5555, 60 mg·kg-1·day-1), PAR2 antagonist (FSLLRY, 3 mg·kg-1·day-1), or E5555 + FSLLRY for 4 wk. The results showed that the urinary albumin creatinine ratio was significantly reduced when both PAR1 and PAR2 were blocked with E5555 + FSLLRY compared with the vehicle-treated group. Dual blockade of PAR1 and PAR2 by E5555 + FSLLRY additively ameliorated histological injury, including mesangial expansion, glomerular macrophage infiltration, and collagen type IV deposition. Marked reduction of inflammation- and fibrosis-related gene expression in the kidney was also observed. In vitro, PAR1 and PAR2 agonists additively increased mRNA expression of macrophage chemoattractant protein 1 or plasminogen activator inhibitor-1 in human endothelial cells. Changes induced by the PAR1 agonist were blocked by a NF-κB inhibitor, whereas those of the PAR2 agonist were blocked by MAPK and/or NF-κB inhibitors. These findings suggest that PAR1 and PAR2 additively contribute to DKD pathogenesis and that dual blockade of both could be a novel therapeutic option for treatment of patients with DKD.


Assuntos
Diabetes Mellitus Tipo 1/tratamento farmacológico , Nefropatias Diabéticas/prevenção & controle , Iminas/farmacologia , Rim/efeitos dos fármacos , Oligopeptídeos/farmacologia , Piridinas/farmacologia , Receptor PAR-1/antagonistas & inibidores , Receptor PAR-2/antagonistas & inibidores , Albuminúria/genética , Albuminúria/metabolismo , Albuminúria/prevenção & controle , Animais , Linhagem Celular , Proliferação de Células/efeitos dos fármacos , Colágeno Tipo IV/metabolismo , Citocinas/metabolismo , Diabetes Mellitus Tipo 1/genética , Diabetes Mellitus Tipo 1/metabolismo , Nefropatias Diabéticas/genética , Nefropatias Diabéticas/metabolismo , Nefropatias Diabéticas/patologia , Modelos Animais de Doenças , Quimioterapia Combinada , Células Endoteliais/efeitos dos fármacos , Células Endoteliais/metabolismo , Fibrose , Humanos , Mediadores da Inflamação/metabolismo , Rim/metabolismo , Rim/patologia , Camundongos da Linhagem 129 , Camundongos Endogâmicos C57BL , Camundongos Knockout , Óxido Nítrico Sintase Tipo III/deficiência , Óxido Nítrico Sintase Tipo III/genética , Receptor PAR-1/metabolismo , Receptor PAR-2/metabolismo , Transdução de Sinais
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