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1.
Inorg Chem ; 60(16): 12610-12620, 2021 Aug 16.
Artigo em Inglês | MEDLINE | ID: mdl-34351146

RESUMO

Herein, we report a new series of bifunctional chelators (BFCs) with a high affinity for amyloid aggregates, a strong binding affinity toward Cu(II), and favorable lipophilicity for potential blood-brain barrier penetration. The alkyl carboxylate ester pendant arms offer up to 3 orders of magnitude higher binding affinity toward Cu(II) and enable the BFCs to form stable 64Cu-radiolabeled complexes. Among the five compounds tested, the 64Cu-YW-7 and 64Cu-YW-10 complexes exhibit strong and specific staining of amyloid plaques in ex vivo autoradiography studies. Importantly, these BFCs have promising partition coefficient (log Doct) values of 0.91-1.26 and show some brain uptake in biodistribution studies using CD-1 mice. Overall, these BFCs could serve as lead compounds for the development of positron emission tomography imaging agents for AD diagnosis.


Assuntos
Doença de Alzheimer/diagnóstico por imagem , Peptídeos beta-Amiloides/metabolismo , Quelantes/química , Quelantes/metabolismo , Radioisótopos de Cobre , Interações Hidrofóbicas e Hidrofílicas , Tomografia por Emissão de Pósitrons , Doença de Alzheimer/metabolismo , Barreira Hematoencefálica/metabolismo
2.
BMC Plant Biol ; 21(1): 372, 2021 Aug 13.
Artigo em Inglês | MEDLINE | ID: mdl-34388971

RESUMO

BACKGROUND: Oilseed rape (B. napus L.) has great potential for phytoremediation of cadmium (Cd)-polluted soils due to its large plant biomass production and strong metal accumulation. Soil properties and the presence of other soluble compounds or ions, cause a heterogeneous distribution of Cd. RESULTS: The aim of our study was to reveal the differential responses of B. napus to different Cd abundances. Herein, we found that high Cd (50 µM) severely inhibited the growth of B. napus, which was not repressed by low Cd (0.50 µM) under hydroponic culture system. ICP-MS assays showed that the Cd2+ concentrations in both shoots and roots under 50 µM Cd were over 10 times higher than those under 0.50 µM Cd. Under low Cd, the concentrations of only shoot Ca2+/Mn2+ and root Mn2+ were obviously changed (both reduced); under high Cd, the concentrations of most cations assayed were significantly altered in both shoots and roots except root Ca2+ and Mg2+. High-throughput transcriptomic profiling revealed a total of 18,021 and 1408 differentially expressed genes under high Cd and low Cd conditions, respectively. The biological categories related to the biosynthesis of plant cell wall components and response to external stimulus were over-accumulated under low Cd, whereas the terms involving photosynthesis, nitrogen transport and response, and cellular metal ion homeostasis were highly enriched under high Cd. Differential expression of the transporters responsible for Cd uptake (NRAMPs), transport (IRTs and ZIPs), sequestration (HMAs, ABCs, and CAXs), and detoxification (MTPs, PCR, MTs, and PCSs), and some other essential nutrient transporters were investigated, and gene co-expression network analysis revealed the core members of these Cd transporters. Some Cd transporter genes, especially NRAMPs and IRTs, showed opposite responsive patterns between high Cd and low Cd conditions. CONCLUSIONS: Our findings would enrich our understanding of the interaction between essential nutrients and Cd, and might also provide suitable gene resources and important implications for the genetic improvement of plant Cd accumulation and resistance through molecular engineering of these core genes under varying Cd abundances in soils.


Assuntos
Brassica napus/genética , Brassica napus/metabolismo , Cádmio/metabolismo , Transporte Biológico , Brassica napus/crescimento & desenvolvimento , Quelantes/metabolismo , Regulação da Expressão Gênica de Plantas , Genes de Plantas , Íons/metabolismo , Solo/química , Tetraploidia , Transcriptoma
3.
RNA ; 27(10): 1257-1264, 2021 10.
Artigo em Inglês | MEDLINE | ID: mdl-34257148

RESUMO

The widespread ykkC-I riboswitch class exemplifies divergent riboswitch evolution. To analyze how natural selection has diversified its versatile RNA fold, we determined the X-ray crystal structure of the Burkholderia sp. TJI49 ykkC-I subtype-1 (Guanidine-I) riboswitch aptamer domain. Differing from the previously reported structures of orthologs from Dickeya dadantii and Sulfobacillus acidophilus, our Burkholderia structure reveals a chelated K+ ion adjacent to two Mg2+ ions in the guanidine-binding pocket. Thermal melting analysis shows that K+ chelation, which induces localized conformational changes in the binding pocket, improves guanidinium-RNA interactions. Analysis of ribosome structures suggests that the [K+(Mg2+)2] ion triad is uncommon. It is, however, reminiscent of metal ion clusters found in the active sites of ribozymes and DNA polymerases. Previous structural characterization of ykkC-I subtype-2 RNAs, which bind the effector ligands ppGpp and PRPP, indicate that in those paralogs, an adenine responsible for K+ chelation in the Burkholderia Guanidine-I riboswitch is replaced by a pyrimidine. This mutation results in a water molecule and Mg2+ ion binding in place of the K+ ion. Thus, our structural analysis demonstrates how ion and solvent chelation tune divergent ligand specificity and affinity among ykkC-I riboswitches.


Assuntos
Burkholderia/genética , Quelantes/química , Guanidinas/química , Magnésio/química , Potássio/química , Riboswitch , Aptâmeros de Nucleotídeos/química , Aptâmeros de Nucleotídeos/genética , Aptâmeros de Nucleotídeos/metabolismo , Pareamento de Bases , Sequência de Bases , Evolução Biológica , Burkholderia/metabolismo , Quelantes/metabolismo , Clostridiales/genética , Clostridiales/metabolismo , Cristalografia por Raios X , Dickeya/genética , Dickeya/metabolismo , Guanidinas/metabolismo , Magnésio/metabolismo , Modelos Moleculares , Mutação , Conformação de Ácido Nucleico , Potássio/metabolismo , Ribossomos/genética , Ribossomos/metabolismo , Água/química , Água/metabolismo
4.
Int J Mol Sci ; 22(14)2021 Jul 19.
Artigo em Inglês | MEDLINE | ID: mdl-34299316

RESUMO

Redox-active metal ions, Cu(I/II) and Fe(II/III), are essential biological molecules for the normal functioning of the brain, including oxidative metabolism, synaptic plasticity, myelination, and generation of neurotransmitters. Dyshomeostasis of these redox-active metal ions in the brain could cause Alzheimer's disease (AD). Thus, regulating the levels of Cu(I/II) and Fe(II/III) is necessary for normal brain function. To control the amounts of metal ions in the brain and understand the involvement of Cu(I/II) and Fe(II/III) in the pathogenesis of AD, many chemical agents have been developed. In addition, since toxic aggregates of amyloid-ß (Aß) have been proposed as one of the major causes of the disease, the mechanism of clearing Aß is also required to be investigated to reveal the etiology of AD clearly. Multiple metalloenzymes (e.g., neprilysin, insulin-degrading enzyme, and ADAM10) have been reported to have an important role in the degradation of Aß in the brain. These amyloid degrading enzymes (ADE) could interact with redox-active metal ions and affect the pathogenesis of AD. In this review, we introduce and summarize the roles, distributions, and transportations of Cu(I/II) and Fe(II/III), along with previously invented chelators, and the structures and functions of ADE in the brain, as well as their interrelationships.


Assuntos
Doença de Alzheimer/metabolismo , Amiloide/metabolismo , Encéfalo/metabolismo , Proteína ADAM10/metabolismo , Doença de Alzheimer/etiologia , Secretases da Proteína Precursora do Amiloide/metabolismo , Peptídeos beta-Amiloides/metabolismo , Barreira Hematoencefálica/metabolismo , Quelantes/metabolismo , Cobre/metabolismo , Humanos , Insulisina/metabolismo , Ferro/metabolismo , Proteínas de Membrana/metabolismo , Metais/metabolismo , Neprilisina/metabolismo , Oxirredução , Proteólise
5.
Int J Mol Sci ; 22(11)2021 May 21.
Artigo em Inglês | MEDLINE | ID: mdl-34064291

RESUMO

The Arg-Gly-Asp (RGD) peptide shows a high affinity for αvß3 integrin, which is overexpressed in new tumor blood vessels and many types of tumor cells. The radiolabeled RGD peptide has been studied for cancer imaging and radionuclide therapy. We have developed a long-term tumor-targeting peptide DOTA-EB-cRGDfK, which combines a DOTA chelator, a truncated Evans blue dye (EB), a modified linker, and cRGDfK peptide. The aim of this study was to evaluate the potential of indium-111(111In) radiolabeled DOTA-EB-cRGDfK in αvß3 integrin-expressing tumors. The human glioblastoma cell line U-87 MG was used to determine the in vitro binding affinity of the radiolabeled peptide. The in vivo distribution of radiolabeled peptides in U-87 MG xenografts was investigated by biodistribution, nanoSPECT/CT, pharmacokinetic and excretion studies. The in vitro competition assay showed that 111In-DOTA-EB-cRGDfK had a significant binding affinity to U-87 MG cancer cells (IC50 = 71.7 nM). NanoSPECT/CT imaging showed 111In-DOTA-EB-cRGDfK has higher tumor uptake than control peptides (111In-DOTA-cRGDfK and 111In-DOTA-EB), and there is still a clear signal until 72 h after injection. The biodistribution results showed significant tumor accumulation (27.1 ± 2.7% ID/g) and the tumor to non-tumor ratio was 22.85 at 24 h after injection. In addition, the pharmacokinetics results indicated that the 111In-DOTA-EB-cRGDfK peptide has a long-term half-life (T1/2λz = 77.3 h) and that the calculated absorbed dose was safe for humans. We demonstrated that radiolabeled DOTA-EB-cRGDfK may be a promising agent for glioblastoma tumor imaging and has the potential as a theranostic radiopharmaceutical.


Assuntos
Quelantes/metabolismo , Glioblastoma/metabolismo , Oligopeptídeos/metabolismo , Animais , Linhagem Celular Tumoral , Compostos Heterocíclicos com 1 Anel/metabolismo , Xenoenxertos/metabolismo , Humanos , Radioisótopos de Índio/metabolismo , Camundongos , Camundongos Endogâmicos NOD , Camundongos SCID , Imagem Molecular/métodos , Peptídeos Cíclicos/metabolismo , Compostos Radiofarmacêuticos/metabolismo , Ratos , Distribuição Tecidual
6.
J Alzheimers Dis ; 82(s1): S179-S193, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34032611

RESUMO

BACKGROUND: Redox active metal cations, such as Cu2 +, have been related to induce amyloid plaques formation and oxidative stress, which are two of the key events in the development of Alzheimer's disease (AD) and others metal promoted neurodegenerative diseases. In these oxidative events, standard reduction potential (SRP) is an important property especially relevant in the reactive oxygen species formation. OBJECTIVE: The SRP is not usually considered for the selection of drug candidates in anti-AD treatments. In this work, we present a computational protocol for the selection of multifunctional ligands with suitable metal chelating, pharmacokinetics, and redox properties. METHODS: The filtering process is based on quantum chemical calculations and the use of in silico tools. Calculations of SRP were performed by using the M06-2X density functional and the isodesmic approach. Then, a virtual screening technique (VS) was used for similar structure search. RESULTS: Protocol application allowed the assessment of chelating, drug likeness, and redox properties of copper ligands. Those molecules showing the best features were selected as molecular scaffolds for a VS procedure in order to obtain related compounds. After applying this process, we present a list of candidates with suitable properties to prevent the redox reactions mediated by copper(II) ion. CONCLUSION: The protocol incorporates SRP in the filtering stage and can be effectively used to obtain a set of potential drug candidates for AD treatments.


Assuntos
Doença de Alzheimer/metabolismo , Quelantes/metabolismo , Química Computacional/métodos , Cobre/metabolismo , Desenho de Fármacos , Doença de Alzheimer/tratamento farmacológico , Barreira Hematoencefálica/efeitos dos fármacos , Barreira Hematoencefálica/metabolismo , Quelantes/síntese química , Quelantes/uso terapêutico , Cobre/química , Cobre/uso terapêutico , Humanos , Ligantes , Oxirredução
7.
Theranostics ; 11(13): 6293-6314, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33995659

RESUMO

Radioimmunotherapy (RIT) is FDA-approved for the clinical management of liquid malignancies, however, its use for solid malignancies remains a challenge. The putative benefit of RIT lies in selective targeting of antigens expressed on the tumor surface using monoclonal antibodies, to systemically deliver cytotoxic radionuclides. The past several decades yielded dramatic improvements in the quality, quantity, recent commercial availability of alpha-, beta- and Auger Electron-emitting therapeutic radiometals. Investigators have created new or improved existing bifunctional chelators. These bifunctional chelators bind radiometals and can be coupled to antigen-specific antibodies. In this review, we discuss approaches to develop radiometal-based RITs, including the selection of radiometals, chelators and antibody platforms (i.e. full-length, F(ab')2, Fab, minibodies, diabodies, scFv-Fc and nanobodies). We cite examples of the performance of RIT in the clinic, describe challenges to its implementation, and offer insights to address gaps toward translation.


Assuntos
Radioimunoterapia/métodos , Compostos Radiofarmacêuticos/uso terapêutico , Animais , Anticorpos Monoclonais/administração & dosagem , Anticorpos Monoclonais/uso terapêutico , Antígenos de Neoplasias/imunologia , Antineoplásicos Imunológicos/administração & dosagem , Antineoplásicos Imunológicos/metabolismo , Antineoplásicos Imunológicos/uso terapêutico , Quelantes/administração & dosagem , Quelantes/metabolismo , Química Click , Ensaios Clínicos como Assunto , Fracionamento da Dose de Radiação , Sistemas de Liberação de Medicamentos , Previsões , Humanos , Fragmentos Fab das Imunoglobulinas/administração & dosagem , Fragmentos Fab das Imunoglobulinas/uso terapêutico , Linfoma não Hodgkin/radioterapia , Camundongos , Terapia de Alvo Molecular , Proteínas de Neoplasias/antagonistas & inibidores , Neoplasias Experimentais/diagnóstico por imagem , Neoplasias Experimentais/radioterapia , Especificidade de Órgãos , Medicina de Precisão , Tolerância a Radiação , Compostos Radiofarmacêuticos/administração & dosagem , Receptores Proteína Tirosina Quinases/antagonistas & inibidores , Anticorpos de Cadeia Única/administração & dosagem , Anticorpos de Cadeia Única/uso terapêutico , Anticorpos de Domínio Único/administração & dosagem , Anticorpos de Domínio Único/uso terapêutico , Radioisótopos de Ítrio/administração & dosagem , Radioisótopos de Ítrio/uso terapêutico
8.
Int J Mol Sci ; 22(9)2021 Apr 27.
Artigo em Inglês | MEDLINE | ID: mdl-33925312

RESUMO

Red cabbage (RC) and purple sweet potato (PSP) are naturally rich in acylated cyanidin glycosides that can bind metal ions and develop intramolecular π-stacking interactions between the cyanidin chromophore and the phenolic acyl residues. In this work, a large set of RC and PSP anthocyanins was investigated for its coloring properties in the presence of iron and aluminum ions. Although relatively modest, the structural differences between RC and PSP anthocyanins, i.e., the acylation site at the external glucose of the sophorosyl moiety (C2-OH for RC vs. C6-OH for PSP) and the presence of coordinating acyl groups (caffeoyl) in PSP anthocyanins only, made a large difference in the color expressed by their metal complexes. For instance, the Al3+-induced bathochromic shifts for RC anthocyanins reached ca. 50 nm at pH 6 and pH 7, vs. at best ca. 20 nm for PSP anthocyanins. With Fe2+ (quickly oxidized to Fe3+ in the complexes), the bathochromic shifts for RC anthocyanins were higher, i.e., up to ca. 90 nm at pH 7 and 110 nm at pH 5.7. A kinetic analysis at different metal/ligand molar ratios combined with an investigation by high-resolution mass spectrometry suggested the formation of metal-anthocyanin complexes of 1:1, 1:2, and 1:3 stoichiometries. Contrary to predictions based on steric hindrance, acylation by noncoordinating acyl residues favored metal binding and resulted in complexes having much higher molar absorption coefficients. Moreover, the competition between metal binding and water addition to the free ligands (leading to colorless forms) was less severe, although very dependent on the acylation site(s). Overall, anthocyanins from purple sweet potato, and even more from red cabbage, have a strong potential for development as food colorants expressing red to blue hues depending on pH and metal ion.


Assuntos
Antocianinas/química , Brassica/química , Ipomoea batatas/química , Pigmentos Biológicos/química , Acilação , Alumínio/química , Alumínio/metabolismo , Antocianinas/metabolismo , Brassica/metabolismo , Quelantes/metabolismo , Cromatografia Líquida de Alta Pressão/métodos , Cor , Corantes de Alimentos , Concentração de Íons de Hidrogênio , Íons/metabolismo , Ipomoea batatas/metabolismo , Ferro/química , Ferro/metabolismo , Cinética , Metais/metabolismo , Fenóis/metabolismo , Extratos Vegetais/química
9.
Biochem Cell Biol ; 99(4): 465-475, 2021 08.
Artigo em Inglês | MEDLINE | ID: mdl-33449856

RESUMO

Biologically important ions such as Ca, K, Mg, Fe, and Zn play major roles in numerous biological processes, and their homeostatic balance is necessary for the maintenance of cellular activities. Sudden and severe loss in homeostasis of just one biologically important ion can cause a cascade of negative effects. The ability to quickly, accurately, and reliably quantify biologically important ions in samples of human bio-fluids is something that has been sorely lacking within the field of metabolomics. 1H-NMR spectra. The foundation of our investigation was the a-priori knowledge that free ethylenediaminetetraacetic acid (EDTA) produces two clear single peaks on 1H-NMR spectra, and that EDTA chelated to different ions produces unique 1H-NMR spectral patterns due to 3D conformational changes in the chemical structure of chelated-EDTA and varying degrees of electronegativity. The aim of this study was to develop and test a 1H-NMR-based method, with application specifically to the field of metabolomics, to quantify biologically important ions within the physiological pH range of 6.50-7.50 using EDTA as a chelating agent. Our method produced linear, accurate, precise, and repeatable results for Ca, Mg, and Zn; however, K and Fe did not chelate with EDTA.


Assuntos
Quelantes/química , Ácido Edético/química , Metabolômica/métodos , Metais/química , Espectroscopia de Prótons por Ressonância Magnética/métodos , Quelantes/metabolismo , Ácido Edético/metabolismo , Humanos , Metais/metabolismo
10.
Carbohydr Polym ; 255: 117335, 2021 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-33436178

RESUMO

Nanocellulose has gained much attention because of its excellent properties. Cationic cellulose nanocrystals (cCNC) shows good adsorptivity toward negative ions and molecules. Phosphate binders are most used to treat hyperphosphatemia and it is significant to develop its alternatives with high specific and low cost in the clinic. Herein, we prepared cCNC and characterized it by FTIR, TEM, dynamic light scattering, and viscosity method. We simulated the binding process of cationic cellulose for phosphate and used it as phosphate binder for hyperphosphatemia therapy to study the phosphate binding effect and evaluate the oral toxicity. Cationic cellulose improved the conditions of mice models and efficiently decreased the level of phosphate in the serum. cCNC had a better binding effect than cationic microcrystalline cellulose both in vitro and in vivo. cCNC could be used as alternatives to phosphate binder for therapy of chronic renal failure and hyperphosphatemia.


Assuntos
Celulose/farmacologia , Quelantes/farmacologia , Hiperfosfatemia/tratamento farmacológico , Rim/efeitos dos fármacos , Nanopartículas/química , Fosfatos/isolamento & purificação , Adenina/administração & dosagem , Adsorção , Animais , Biomarcadores/sangue , Celulose/química , Celulose/metabolismo , Quelantes/metabolismo , HDL-Colesterol/sangue , LDL-Colesterol/sangue , Modelos Animais de Doenças , Fezes/química , Humanos , Hiperfosfatemia/induzido quimicamente , Hiperfosfatemia/metabolismo , Hiperfosfatemia/patologia , Intestino Delgado/efeitos dos fármacos , Intestino Delgado/metabolismo , Rim/metabolismo , Fígado/efeitos dos fármacos , Fígado/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Nanopartículas/administração & dosagem , Fosfatos/metabolismo , Resultado do Tratamento , Triglicerídeos/sangue
11.
J Food Biochem ; 45(1): e13557, 2021 01.
Artigo em Inglês | MEDLINE | ID: mdl-33171544

RESUMO

SARS-CoV-2 (previously 2019-nCoV), the pathogenic agent of COVID-19 disease, started to expand from Wuhan, China, on December 2019 and in 2 months, it spread worldwide giving origin to a pandemic. COVID-19 has a stronger transmission capacity by inhalation of infectious aerosols and after an incubation time of 3-14 days, it may be responsible for diseases ranging from the asymptomatic to fatal consequences. COVID-19 has emerged as a multifaceted, multisystem, multi-organ disorder, which produces its pathogenic effects through a quite ubiquitous target at the level of multiple organs and in which oxidative stress and inflammatory process play relevant roles. Thus, besides the development of a pharmacological therapy, in the field of alternative and coadjutant therapeutic, the use of dietary supplements or nutraceuticals for the prevention or treatment of SARS-CoV-2 infection may be a useful strategy. Herein, we specifically comment on some literature evidences, which link the food-derived antioxidants and metal-chelating agents with treatment and prevention of oxidative stress and inflammation that play a key role in the progression of COVID-19. PRACTICAL APPLICATIONS: Oxidative stress and inflammation are key factors increasing COVID-19 severity especially in the presence of chronic diseases associated with the antioxidant system fragility. These evidences support the recommendation of antioxidants supplementation as useful strategies against COVID-19. In light with these observations, herein, a comment which describes the major antioxidants and metal-chelating agents from food sources that might be useful for the treatment and prevention of oxidative stress and inflammation during COVID-19.


Assuntos
Antioxidantes/metabolismo , COVID-19/dietoterapia , Extratos Vegetais/metabolismo , COVID-19/metabolismo , COVID-19/virologia , Quelantes/metabolismo , Suplementos Nutricionais/análise , Análise de Alimentos , Humanos , Estresse Oxidativo , SARS-CoV-2/fisiologia
12.
Nat Biotechnol ; 39(3): 357-367, 2021 03.
Artigo em Inglês | MEDLINE | ID: mdl-33077961

RESUMO

Depletion of mitochondrial copper, which shifts metabolism from respiration to glycolysis and reduces energy production, is known to be effective against cancer types that depend on oxidative phosphorylation. However, existing copper chelators are too toxic or ineffective for cancer treatment. Here we develop a safe, mitochondria-targeted, copper-depleting nanoparticle (CDN) and test it against triple-negative breast cancer (TNBC). We show that CDNs decrease oxygen consumption and oxidative phosphorylation, cause a metabolic switch to glycolysis and reduce ATP production in TNBC cells. This energy deficiency, together with compromised mitochondrial membrane potential and elevated oxidative stress, results in apoptosis. CDNs should be less toxic than existing copper chelators because they favorably deprive copper in the mitochondria in cancer cells instead of systemic depletion. Indeed, we demonstrate low toxicity of CDNs in healthy mice. In three mouse models of TNBC, CDN administration inhibits tumor growth and substantially improves survival. The efficacy and safety of CDNs suggest the potential clinical relevance of this approach.


Assuntos
Cobre/metabolismo , Mitocôndrias/metabolismo , Neoplasias de Mama Triplo Negativas/patologia , Animais , Morte Celular , Linhagem Celular Tumoral , Quelantes/metabolismo , Modelos Animais de Doenças , Feminino , Humanos , Camundongos , Fosforilação Oxidativa , Neoplasias de Mama Triplo Negativas/metabolismo
13.
J Inorg Biochem ; 215: 111317, 2021 02.
Artigo em Inglês | MEDLINE | ID: mdl-33310459

RESUMO

Palladium catalysed reactions are ubiquitous in synthetic organic chemistry in both organic solvents and aqueous buffers. The broad reactivity of palladium catalysis has drawn interest as a means to conduct orthogonal transformations in biological settings. Successful examples have been shown for protein modification, in vivo drug decaging and as palladium-protein biohybrid catalysts for selective catalysis. Biological media represents a challenging environment for palladium chemistry due to the presence of a multitude of chelators, catalyst poisons and a requirement for milder reaction conditions e.g. lower temperatures. This review looks to identify successful examples of palladium-catalysed reactions in the presence of proteins or cells and analyse solutions to help to overcome the challenges of working in biological systems.


Assuntos
Paládio/química , Paládio/metabolismo , Catálise , Quelantes/metabolismo , Cisteína/metabolismo , Humanos , Proteínas/metabolismo , Solventes , Elementos de Transição
14.
Biochim Biophys Acta Mol Cell Res ; 1868(1): 118885, 2021 01.
Artigo em Inglês | MEDLINE | ID: mdl-33045305

RESUMO

To maintain iron homeostasis, fungi have to balance iron acquisition, storage, and utilization to ensure sufficient supply and to avoid toxic excess of this essential trace element. As pathogens usually encounter iron limitation in the host niche, this metal plays a particular role during virulence. Siderophores are iron-chelators synthesized by most, but not all fungal species to sequester iron extra- and intracellularly. In recent years, the facultative human pathogen Aspergillus fumigatus has become a model for fungal iron homeostasis of siderophore-producing fungal species. This article summarizes the knowledge on fungal iron homeostasis and its links to virulence with a focus on A. fumigatus. It covers mechanisms for iron acquisition, storage, and detoxification, as well as the modes of transcriptional iron regulation and iron sensing in A. fumigatus in comparison to other fungal species. Moreover, potential translational applications of the peculiarities of fungal iron metabolism for treatment and diagnosis of fungal infections is addressed.


Assuntos
Aspergillus fumigatus/genética , Homeostase/genética , Ferro/metabolismo , Sideróforos/genética , Aspergillus fumigatus/metabolismo , Aspergillus fumigatus/patogenicidade , Quelantes/química , Quelantes/metabolismo , Proteínas Fúngicas/genética , Regulação Fúngica da Expressão Gênica , Humanos , Ferro/química , Proteínas Repressoras/genética , Virulência/genética
15.
J Mater Chem B ; 9(1): 80-84, 2021 01 07.
Artigo em Inglês | MEDLINE | ID: mdl-33313613

RESUMO

Specific and expeditious identification and enrichment of target proteins in living cells is often a challenging task. The hexahistidine (6His) tag is frequently used to label artificially engineered proteins produced in prokaryotic or eukaryotic cells. Utilizing the interaction between 6His-tag and nitrilotriacetic acid (NTA) mediated by divalent metal ions (Ni2+, Cu2+, Zn2+ or Co2+), we designed and synthesized a series of Nap-G/Biotin/ANA-FFpYGK-NTA probes that, assisted by alkaline phosphatase (ALP), self-assemble into nanofibers. The probe consists of an NTA group that specifically binds to 6His-tag, an FFpY group that promotes self-assembly facilitated by ALP, and a hydrophobic (Nap-G/ANA/Biotin) capping group for various applications. We demonstrate that the ANA-FFpYGK-NTA(Ni2+) nanofibers are fit for real-time tracking of His-tagged protein in living cells, and the Biotin-FFpYGK-NTA(Ni2+) nanofibers are for isolating His-tagged proteins and other proteins that they interact with.


Assuntos
Quelantes/metabolismo , Citoplasma/metabolismo , Histidina/metabolismo , Nanofibras , Ácido Nitrilotriacético/metabolismo , Oligopeptídeos/metabolismo , Quelantes/análise , Citoplasma/química , Corantes Fluorescentes/análise , Corantes Fluorescentes/metabolismo , Histidina/análise , Humanos , Células MCF-7 , Nanofibras/análise , Ácido Nitrilotriacético/análise , Oligopeptídeos/análise
16.
Mar Drugs ; 18(12)2020 Nov 27.
Artigo em Inglês | MEDLINE | ID: mdl-33260992

RESUMO

Protein hydrolysates show great promise as bioactive food and feed ingredients and for valorization of side-streams from e.g., the fish processing industry. We present a novel approach for hydrolysate characterization that utilizes proteomics data for calculation of weighted mean peptide properties (length, molecular weight, and charge) and peptide-level abundance estimation. Using a novel bioinformatic approach for subsequent prediction of biofunctional properties of identified peptides, we are able to provide an unprecedented, in-depth characterization. The study further characterizes bulk emulsifying, foaming, and in vitro antioxidative properties of enzymatic hydrolysates derived from cod frame by application of Alcalase and Neutrase, individually and sequentially, as well as the influence of heat pre-treatment. All hydrolysates displayed comparable or higher emulsifying activity and stability than sodium caseinate. Heat-treatment significantly increased stability but showed a negative effect on the activity and degree of hydrolysis. Lower degrees of hydrolysis resulted in significantly higher chelating activity, while the opposite was observed for radical scavenging activity. Combining peptide abundance with bioinformatic prediction, we identified several peptides that are likely linked to the observed differences in bulk emulsifying properties. The study highlights the prospects of applying proteomics and bioinformatics for hydrolysate characterization and in food protein science.


Assuntos
Antioxidantes/farmacologia , Quelantes/farmacologia , Biologia Computacional , Emulsificantes/farmacologia , Proteínas de Peixes/farmacologia , Gadiformes/metabolismo , Fragmentos de Peptídeos/farmacologia , Proteoma , Proteômica , Animais , Antioxidantes/metabolismo , Quelantes/metabolismo , Emulsificantes/metabolismo , Proteínas de Peixes/metabolismo , Metaloendopeptidases/metabolismo , Fragmentos de Peptídeos/metabolismo , Estabilidade Proteica , Proteólise , Subtilisinas/metabolismo
17.
Nat Commun ; 11(1): 6087, 2020 11 30.
Artigo em Inglês | MEDLINE | ID: mdl-33257696

RESUMO

Inositol polyphosphates are vital metabolic and secondary messengers, involved in diverse cellular functions. Therefore, tight regulation of inositol polyphosphate metabolism is essential for proper cell physiology. Here, we describe an early-onset neurodegenerative syndrome caused by loss-of-function mutations in the multiple inositol-polyphosphate phosphatase 1 gene (MINPP1). Patients are found to have a distinct type of Pontocerebellar Hypoplasia with typical basal ganglia involvement on neuroimaging. We find that patient-derived and genome edited MINPP1-/- induced stem cells exhibit an inefficient neuronal differentiation combined with an increased cell death. MINPP1 deficiency results in an intracellular imbalance of the inositol polyphosphate metabolism. This metabolic defect is characterized by an accumulation of highly phosphorylated inositols, mostly inositol hexakisphosphate (IP6), detected in HEK293 cells, fibroblasts, iPSCs and differentiating neurons lacking MINPP1. In mutant cells, higher IP6 level is expected to be associated with an increased chelation of intracellular cations, such as iron or calcium, resulting in decreased levels of available ions. These data suggest the involvement of IP6-mediated chelation on Pontocerebellar Hypoplasia disease pathology and thereby highlight the critical role of MINPP1 in the regulation of human brain development and homeostasis.


Assuntos
Doenças Cerebelares/metabolismo , Quelantes/metabolismo , Citoplasma/metabolismo , Monoéster Fosfórico Hidrolases/metabolismo , Ácido Fítico/metabolismo , Animais , Morte Celular , Diferenciação Celular , Doenças Cerebelares/diagnóstico por imagem , Doenças Cerebelares/patologia , Criança , Pré-Escolar , Feminino , Técnicas de Inativação de Genes , Células HEK293 , Homeostase , Humanos , Lactente , Masculino , Camundongos Endogâmicos C57BL , Camundongos Knockout , Mutação , Transtornos do Neurodesenvolvimento/metabolismo , Monoéster Fosfórico Hidrolases/genética , Monoéster Fosfórico Hidrolases/farmacologia , Fosforilação , Células-Tronco/efeitos dos fármacos , Transcriptoma
18.
Biochem Pharmacol ; 182: 114267, 2020 12.
Artigo em Inglês | MEDLINE | ID: mdl-33035509

RESUMO

BACKGROUND: Hydrogen sulfide (H2S) is an endogenous mammalian gasotransmitter. Cystathionine ß-synthase (CBS), cystathionine γ-lyase (CSE) and 3-mercaptopyruvate sulfurtransferase (3-MST) are the principal enzymes responsible for its biogenesis. A recent yeast screen suggested that disulfiram (a well-known inhibitor of aldehyde dehydrogenase and a clinically used drug in the treatment of alcoholism) may inhibit CBS in a cell-based environment. However, prior studies have not observed any direct inhibition of CBS by disulfiram. We investigated the potential role of bioconversion of disulfiram to bis(N,N-diethyldithiocarbamate)-copper(II) complex (CuDDC) in the inhibitory effect of disulfiram on H2S production and assessed its effect in two human cell types with high CBS expression: HCT116 colon cancer cells and Down syndrome (DS) fibroblasts. METHODS: H2S production from recombinant human CBS, CSE and 3-MST was measured using the fluorescent H2S probe AzMC. Mouse liver homogenate (a rich source of CBS) was also employed to measure H2S biosynthesis. The interaction of copper with accessible protein cysteine residues was evaluated using the DTNB method. Cell proliferation and viability were measured using the BrdU and MTT methods. Cellular bioenergetics was evaluated by Extracellular Flux Analysis. RESULTS: While disulfiram did not exert any significant direct inhibitory effect on any of the H2S-producing enzymes, its metabolite, CuDDC was a potent inhibitor of CBS and CSE. The mode of its action is likely related to the complexed copper molecule. In cell-based systems, the effects of disulfiram were variable. In colon cancer cells, no significant effect of disulfiram was observed on H2S production or proliferation or viability. In contrast, in DS fibroblasts, disulfiram inhibited H2S production and improved proliferation and viability. Copper, on its own, failed to have any effects on either cell type, likely due to its low cell penetration. CuDDC inhibited H2S production in both cell types studied and exerted the functional effects that would be expected from a CBS inhibitor: inhibition of cell proliferation of cancer cells and a bell-shaped effect (stimulation of proliferation at low concentration and inhibition of these responses at higher concentration) in DS cells. Control experiments using a chemical H2S donor showed that, in addition to inhibiting CBS and CSE, part of the biological effects of CuDDC relates to a direct reaction with H2S, which occurs through its complexed copper. CONCLUSIONS: Disulfiram, via its metabolite CuDDC acts as an inhibitor of CBS and a scavenger of H2S, which, in turn, potently suppresses H2S levels in various cell types. Inhibition of H2S biosynthesis may explain some of the previously reported actions of disulfiram and CuDDC in vitro and in vivo. Disulfiram or CuDDC may be considered as potential agents for the experimental therapy of various pathophysiological conditions associated with H2S overproduction.


Assuntos
Inibidores de Acetaldeído Desidrogenases/farmacologia , Cobre/farmacologia , Cistationina beta-Sintase/antagonistas & inibidores , Dissulfiram/farmacologia , Ditiocarb/análogos & derivados , Compostos Organometálicos/farmacologia , Inibidores de Acetaldeído Desidrogenases/metabolismo , Animais , Sobrevivência Celular/efeitos dos fármacos , Sobrevivência Celular/fisiologia , Quelantes/metabolismo , Quelantes/farmacologia , Cobre/metabolismo , Cistationina beta-Sintase/metabolismo , Dissulfiram/metabolismo , Ditiocarb/metabolismo , Ditiocarb/farmacologia , Relação Dose-Resposta a Droga , Feminino , Células HCT116 , Humanos , Fígado/efeitos dos fármacos , Fígado/metabolismo , Camundongos , Camundongos Endogâmicos BALB C , Compostos Organometálicos/metabolismo
19.
Inorg Chem ; 59(22): 16095-16108, 2020 Nov 16.
Artigo em Inglês | MEDLINE | ID: mdl-33112609

RESUMO

A growing number of copper(II) complexes have been identified as suitable candidates for biomedical applications. Here, we show that the biocompatibility and stability of copper(II) complexes can be tuned by directed ligand design and complex geometry. We demonstrate that azamacrocycle-based chelators that envelope copper(II) in a five-coordinate, distorted trigonal-bipyramidal structure are more chemically inert to redox-mediated structural changes than their six-coordinate, Jahn-Teller-distorted counterparts, as evidenced by electrochemical, crystallographic, electron paramagnetic resonance, and density functional theory studies. We further validated our hypothesis of enhanced inertness in vitro and in vivo by employing Cu-64 radiolabeling of bifunctional analogues appended to a prostate-specific membrane antigen targeting dipeptide. The corresponding Cu-64 complexes were tested for stability in vitro and in vivo, with the five-coordinate system demonstrating the greatest metabolic stability among the studied picolinate complex series.


Assuntos
Quelantes/metabolismo , Complexos de Coordenação/metabolismo , Cobre/metabolismo , Ácidos Picolínicos/metabolismo , Quelantes/química , Complexos de Coordenação/química , Cobre/química , Cristalografia por Raios X , Teoria da Densidade Funcional , Ligantes , Modelos Moleculares , Estrutura Molecular , Oxirredução , Ácidos Picolínicos/química
20.
J Agric Food Chem ; 68(40): 11290-11300, 2020 Oct 07.
Artigo em Inglês | MEDLINE | ID: mdl-32914618

RESUMO

A novel nonapeptide DTDSEEEIR identified from Antarctic krill (Euphausia superba) iron-binding peptides was used in this study to analyze its iron-binding sites and structural changes after iron coordination. The enzymatic resistance and transport of DTDSEEEIR-iron during gastrointestinal digestion and absorption as well as the relationship between the DTDSEEEIR stability and the enhancement of iron absorption were further explored. Results revealed that iron ions spontaneously bound to the carboxyl, hydroxyl, and amino groups of the DTDSEEEIR peptide, which induced the folding of DTDSEEEIR to form a more orderly structure. The DTDSEEEIR peptide remained stable to a certain extent (79.60 ± 0.19%) after gastrointestinal digestion and the coordination of iron improved the digestive stability of the DTDSEEEIR peptide (93.89 ± 1.37%). Moreover, the stability of DTDSEEEIR across intestinal epithelium had a positive effect on iron absorption, which implied that DTDSEEEIR might carry iron ions through intestinal epithelial cells.


Assuntos
Quelantes/química , Euphausiacea/química , Intestino Delgado/metabolismo , Ferro/química , Ferro/metabolismo , Peptídeos/química , Animais , Regiões Antárticas , Quelantes/metabolismo , Digestão , Humanos , Ligantes , Peptídeos/metabolismo
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