Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 938
Filtrar
1.
Food Chem ; 384: 132614, 2022 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-35413775

RESUMO

Due to the importance of diseases associated with oxidative stress, the search for natural antioxidants proves to be essential. This work aimed to compare the chemical composition and antioxidant potential of essential oils from the genus Lippia L. through chemometric analysis. The essential oils were characterized by gas chromatography coupled with mass spectrometry. Antioxidant potentials were determined by DPPH, ABTS, Deoxyribose and ß-carotene protection, Iron chelation and reduction methods. All data were related by multivariate analyzes. Essential oils showed low similar chemical compositions and no statistically significant relationship. These showed relevant antioxidant activity, especially for L. sidoides that obtained IC50 of 5.22 ± 0.08 µg/mL in ABTS capture. Multivariate analyzes showed the effectiveness of L. alba compounds to DPPH scavenging, Fe3+ reduction and ß-carotene protection, and L. gracilis components to deoxyribose protect. Thus, studies proving the antioxidant potential of Lippia compounds against oxidative stress and their use in food conservation are fundamental.


Assuntos
Lippia , Óleos Voláteis , Antioxidantes/química , Desoxirribose , Cromatografia Gasosa-Espectrometria de Massas , Lippia/química , Óleos Voláteis/química , Óleos Vegetais/química , beta Caroteno/química
2.
Cells ; 11(6)2022 03 11.
Artigo em Inglês | MEDLINE | ID: mdl-35326409

RESUMO

Catechin is an extensively investigated plant flavan-3-ol with a beneficial impact on human health that is often associated with antioxidant activities and iron coordination complex formation. The aim of this study was to explore these properties with FeII and FeIII using a combination of nanoelectrospray-mass spectrometry, differential pulse voltammetry, site-specific deoxyribose degradation assay, FeII autoxidation assay, and brine shrimp mortality assay. Catechin primarily favored coordination complex formation with Fe ions of the stoichiometry catechin:Fe in the ratio of 1:1 or 2:1. In the detected Fe-catechin coordination complexes, FeII prevailed. Differential pulse voltammetry, the site-specific deoxyribose degradation, and FeII autoxidation assays proved that coordination complex formation affected catechin's antioxidant effects. In situ formed Fe-catechin coordination complexes showed no toxic activities in the brine shrimp mortality assay. In summary, catechin has properties for the possible treatment of pathological processes associated with ageing and degeneration, such as Alzheimer's and Parkinson's diseases.


Assuntos
Catequina , Complexos de Coordenação , Antioxidantes/química , Antioxidantes/farmacologia , Catequina/química , Catequina/farmacologia , Complexos de Coordenação/farmacologia , Desoxirribose/química , Desoxirribose/metabolismo , Compostos Férricos , Compostos Ferrosos , Humanos , Espectrometria de Massas
3.
Chem Res Toxicol ; 35(2): 203-217, 2022 02 21.
Artigo em Inglês | MEDLINE | ID: mdl-35124963

RESUMO

Abasic sites are common in cellular and synthetic DNA. As a result, it is important to characterize the chemical fate of these lesions. Amine-catalyzed strand cleavage at abasic sites in DNA is an important process in which conversion of small amounts of the ring-opened abasic aldehyde residue to an iminium ion facilitates ß-elimination of the 3'-phosphoryl group. This reaction generates a trans-α,ß-unsaturated iminium ion on the 3'-terminus of the strand break as an obligate intermediate. The canonical product expected from amine-catalyzed cleavage at an AP site is the corresponding trans-α,ß-unsaturated aldehyde sugar remnant resulting from hydrolysis of this iminium ion. Interestingly, a handful of studies have reported noncanonical 3'-sugar remnants generated by amine-catalyzed strand cleavage, but the formation and properties of these products are not well-understood. To address this knowledge gap, a nucleoside system was developed that enabled chemical characterization of the sugar remnants generated by amine-catalyzed ß-elimination in the 2-deoxyribose system. The results predict that amine-catalyzed strand cleavage at an AP site under physiological conditions has the potential to reversibly generate noncanonical cleavage products including cis-alkenal, 3-thio-2,3-dideoxyribose, and 2-deoxyribose groups alongside the canonical trans-alkenal residue on the 3'-terminus of the strand break. Thus, the model reactions provide evidence that the products generated by amine-catalyzed strand cleavage at abasic sites in cellular DNA may be more complex that commonly thought, with trans-α,ß-unsaturated iminium ion intermediates residing at the hub of interconverting product mixtures. The results expand the list of possible 3'-sugar remnants arising from amine-catalyzed cleavage of abasic sites in DNA that must be chemically or enzymatically removed for the completion of base excision repair and single-strand break repair in cells.


Assuntos
Aminas/química , Materiais Biomiméticos/química , DNA/efeitos dos fármacos , Desoxirribose/química , Nucleosídeos/química , Catálise , Dano ao DNA , Reparo do DNA , Conformação de Ácido Nucleico
4.
Int J Mol Sci ; 22(21)2021 Oct 23.
Artigo em Inglês | MEDLINE | ID: mdl-34768868

RESUMO

2-deoxy-D-Ribose (2dDR) was first identified in 1930 in the structure of DNA and discovered as a degradation product of it later when the enzyme thymidine phosphorylase breaks down thymidine into thymine. In 2017, our research group explored the development of wound dressings based on the delivery of this sugar to induce angiogenesis in chronic wounds. In this review, we will survey the small volume of conflicting literature on this and related sugars, some of which are reported to be anti-angiogenic. We review the evidence of 2dDR having the ability to stimulate a range of pro-angiogenic activities in vitro and in a chick pro-angiogenic bioassay and to stimulate new blood vessel formation and wound healing in normal and diabetic rat models. The biological actions of 2dDR were found to be 80 to 100% as effective as VEGF in addition to upregulating the production of VEGF. We then demonstrated the uptake and delivery of the sugar from a range of experimental and commercial dressings. In conclusion, its pro-angiogenic properties combined with its improved stability on storage compared to VEGF, its low cost, and ease of incorporation into a range of established wound dressings make 2dDR an attractive alternative to VEGF for wound dressing development.


Assuntos
Desoxirribose/farmacologia , Fatores de Crescimento do Endotélio Vascular/metabolismo , Cicatrização/efeitos dos fármacos , Indutores da Angiogênese/química , Animais , Bandagens/tendências , Fenômenos Fisiológicos Cardiovasculares/efeitos dos fármacos , Desoxirribose/metabolismo , Humanos , Morfogênese/efeitos dos fármacos , Neovascularização Fisiológica/efeitos dos fármacos , Neovascularização Fisiológica/fisiologia , Ribose/metabolismo , Ribose/farmacologia , Fatores de Crescimento do Endotélio Vascular/efeitos dos fármacos
5.
Molecules ; 26(19)2021 Sep 30.
Artigo em Inglês | MEDLINE | ID: mdl-34641475

RESUMO

Many strategies have been developed to modulate the biological or biotechnical properties of oligonucleotides by introducing new chemical functionalities or by enhancing their affinity and specificity while restricting their conformational space. Among them, we review our approach consisting of modifications of the 5'-C-position of the nucleoside sugar. This allows the introduction of an additional chemical handle at any position on the nucleotide chain without disturbing the Watson-Crick base-pairing. We show that 5'-C bromo or propargyl convertible nucleotides (CvN) are accessible in pure diastereoisomeric form, either for nucleophilic displacement or for CuAAC conjugation. Alternatively, the 5'-carbon can be connected in a stereo-controlled manner to the phosphate moiety of the nucleotide chain to generate conformationally constrained nucleotides (CNA). These allow the precise control of the sugar/phosphate backbone torsional angles. The consequent modulation of the nucleic acid shape induces outstanding stabilization properties of duplex or hairpin structures in accordance with the preorganization concept. Some biological applications of these distorted oligonucleotides are also described. Effectively, the convertible and the constrained approaches have been merged to create constrained and convertible nucleotides (C2NA) providing unique tools to functionalize and stabilize nucleic acids.


Assuntos
Desoxirribose/química , Nucleotídeos/química , Pareamento de Bases , Modelos Moleculares , Conformação de Ácido Nucleico
6.
Int J Mol Sci ; 22(9)2021 Apr 29.
Artigo em Inglês | MEDLINE | ID: mdl-33947069

RESUMO

The accurate knowledge of the elastic properties of single-stranded DNA (ssDNA) is key to characterize the thermodynamics of molecular reactions that are studied by force spectroscopy methods where DNA is mechanically unfolded. Examples range from DNA hybridization, DNA ligand binding, DNA unwinding by helicases, etc. To date, ssDNA elasticity has been studied with different methods in molecules of varying sequence and contour length. A dispersion of results has been reported and the value of the persistence length has been found to be larger for shorter ssDNA molecules. We carried out pulling experiments with optical tweezers to characterize the elastic response of ssDNA over three orders of magnitude in length (60-14 k bases). By fitting the force-extension curves (FECs) to the Worm-Like Chain model we confirmed the above trend:the persistence length nearly doubles for the shortest molecule (60 b) with respect to the longest one (14 kb). We demonstrate that the observed trend is due to the different force regimes fitted for long and short molecules, which translates into two distinct elastic regimes at low and high forces. We interpret this behavior in terms of a force-induced sugar pucker conformational transition (C3'-endo to C2'-endo) upon pulling ssDNA.


Assuntos
DNA de Cadeia Simples/química , Desoxirribose/química , Conformação de Ácido Nucleico , DNA de Cadeia Simples/ultraestrutura , Elasticidade , Pinças Ópticas , Estresse Mecânico , Termodinâmica
7.
Nat Commun ; 12(1): 796, 2021 02 04.
Artigo em Inglês | MEDLINE | ID: mdl-33542236

RESUMO

RNA polymerases (RNAPs) synthesize RNA from NTPs, whereas DNA polymerases synthesize DNA from 2'dNTPs. DNA polymerases select against NTPs by using steric gates to exclude the 2'OH, but RNAPs have to employ alternative selection strategies. In single-subunit RNAPs, a conserved Tyr residue discriminates against 2'dNTPs, whereas selectivity mechanisms of multi-subunit RNAPs remain hitherto unknown. Here, we show that a conserved Arg residue uses a two-pronged strategy to select against 2'dNTPs in multi-subunit RNAPs. The conserved Arg interacts with the 2'OH group to promote NTP binding, but selectively inhibits incorporation of 2'dNTPs by interacting with their 3'OH group to favor the catalytically-inert 2'-endo conformation of the deoxyribose moiety. This deformative action is an elegant example of an active selection against a substrate that is a substructure of the correct substrate. Our findings provide important insights into the evolutionary origins of biopolymers and the design of selective inhibitors of viral RNAPs.


Assuntos
Proteínas de Bactérias/metabolismo , RNA Polimerases Dirigidas por DNA/metabolismo , Desoxirribonucleotídeos/metabolismo , Desoxirribose/metabolismo , Arginina/metabolismo , Proteínas de Bactérias/genética , Proteínas de Bactérias/isolamento & purificação , Proteínas de Bactérias/ultraestrutura , Cristalografia por Raios X , RNA Polimerases Dirigidas por DNA/genética , RNA Polimerases Dirigidas por DNA/isolamento & purificação , RNA Polimerases Dirigidas por DNA/ultraestrutura , Escherichia coli/enzimologia , Escherichia coli/genética , Cinética , Simulação de Acoplamento Molecular , Regiões Promotoras Genéticas , Proteínas Recombinantes/genética , Proteínas Recombinantes/isolamento & purificação , Proteínas Recombinantes/metabolismo , Proteínas Recombinantes/ultraestrutura , Especificidade por Substrato , Thermus thermophilus/enzimologia , Thermus thermophilus/genética
8.
Int J Mol Sci ; 22(4)2021 Feb 09.
Artigo em Inglês | MEDLINE | ID: mdl-33572317

RESUMO

In this work, we used ωB97XD density functional and 6-31++G** basis set to study the structure, electron affinity, populations via Boltzmann distribution, and one-electron reduction potentials (E°) of 2'-deoxyribose sugar radicals in aqueous phase by considering 2'-deoxyguanosine and 2'-deoxythymidine as a model of DNA. The calculation predicted the relative stability of sugar radicals in the order C4'• > C1'• > C5'• > C3'• > C2'•. The Boltzmann distribution populations based on the relative stability of the sugar radicals were not those found for ionizing radiation or OH-radical attack and are good evidence the kinetic mechanisms of the processes drive the products formed. The adiabatic electron affinities of these sugar radicals were in the range 2.6-3.3 eV which is higher than the canonical DNA bases. The sugar radicals reduction potentials (E°) without protonation (-1.8 to -1.2 V) were also significantly higher than the bases. Thus the sugar radicals will be far more readily reduced by solvated electrons than the DNA bases. In the aqueous phase, these one-electron reduced sugar radicals (anions) are protonated from solvent and thus are efficiently repaired via the "electron-induced proton transfer mechanism". The calculation shows that, in comparison to efficient repair of sugar radicals by the electron-induced proton transfer mechanism, the repair of the cyclopurine lesion, 5',8-cyclo-2'-dG, would involve a substantial barrier.


Assuntos
DNA/química , Desoxirribose/química , Elétrons , Teoria da Densidade Funcional , Radicais Livres/química , Oxirredução , Prótons
9.
PLoS One ; 16(1): e0244804, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33471817

RESUMO

Exercise has beneficial effects on metabolism and health. Although the skeletal muscle has been a primary focus, exercise also mediates robust adaptations in white adipose tissue. To determine if exercise affects in vivo adipocyte formation, fifty-two, sixteen-week-old C57BL/6J mice were allowed access to unlocked running wheels [Exercise (EX) group; n = 13 males, n = 13 females] or to locked wheels [Sedentary (SED) group; n = 13 males, n = 13 females] for 4-weeks. In vivo adipocyte formation was assessed by the incorporation of deuterium (2H) into the DNA of newly formed adipocytes in the inguinal and gonadal adipose depots. A two-way ANOVA revealed that exercise significantly decreased new adipocyte formation in the adipose tissue of mice in the EX group relative to the SED group (activity effect; P = 0.02). This reduction was observed in male and female mice (activity effect; P = 0.03). Independent analysis of the depots showed a significant reduction in adipocyte formation in the inguinal (P = 0.05) but not in the gonadal (P = 0.18) of the EX group. We report for the first time that exercise significantly reduced in vivo adipocyte formation in the adipose tissue of EX mice using a physiologic metabolic 2H2O-labeling protocol.


Assuntos
Adipócitos/metabolismo , Tecido Adiposo/metabolismo , Adipócitos/citologia , Tecido Adiposo/citologia , Animais , DNA/química , DNA/metabolismo , Desoxirribose/análise , Óxido de Deutério/metabolismo , Feminino , Cromatografia Gasosa-Espectrometria de Massas , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Condicionamento Físico Animal , Comportamento Sedentário
10.
Phys Chem Chem Phys ; 23(2): 1424-1436, 2021 Jan 21.
Artigo em Inglês | MEDLINE | ID: mdl-33393943

RESUMO

Among the constituent molecular classes of proteins and nucleic acids, the presence of Ribose and deoxy-Ribose in space remains unclear. Here, we provide experimental evidence of astronomically related sugar derivatives - carbon cluster (fullerenes and graphenes)/prebiotic sugar complexes - and study their formation processes in the gas phase. The results show that, with PAH cations (dicoronylene, DC, C48H20+)/(2-deoxy-d-Ribose, dR, C5H10O4, and dehydrated 2-deoxy-d-Ribose, DedR, C5H8O3) and fullerene cations (C60+)/(dR and DedR) as the initial molecular precursors, two series of graphene-prebiotic sugar cluster cations (graphene/dR and graphene/DedR, e.g., (dR)Cn+ and (DedR)Cn+) and two series of fullerene-prebiotic sugar cluster cations (fullerene/dR and fullerene/DedR, e.g., (dR)(DedR)2Cn+, (DedR)3Cn+, and (dR)2(DedR)Cn+) are formed through an ion-molecule reaction pathway under the influence of a strong radiation field. The structures of the newly formed complexes and the binding energies of these formation reactions are initially theoretically calculated. These laboratory studies attest to the importance of ion-molecule reaction synthesis routes for the chemical complexity in space, demonstrating that the gas phase interstellar materials could directly lead to the formation of large and complex sugar derivatives in a bottom-up growth process. The chemical evolution in space in which single molecules are transformed into complex molecules produces a wide variety of organic compounds (e.g., carbon cluster (fullerenes and graphenes)/prebiotic sugar complexes). For their astrobiological implications, this opens up aromatic based biogenic chemistry that is available to the parent of PAHs or fullerenes in the interstellar environments.


Assuntos
Desoxirribose/análogos & derivados , Fulerenos/química , Gases/química , Grafite/química , Desoxirribose/síntese química , Evolução Química , Grafite/síntese química
11.
Anal Bioanal Chem ; 413(2): 403-418, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33140127

RESUMO

This study examines the information potential of comprehensive two-dimensional gas chromatography combined with time-of-flight mass spectrometry (GC×GC-TOF MS) and variable ionization energy (i.e., Tandem Ionization™) to study changes in saliva metabolic signatures from a small group of obese individuals. The study presents a proof of concept for an effective exploitation of the complementary nature of tandem ionization data. Samples are taken from two sub-populations of severely obese (BMI > 40 kg/m2) patients, named metabolically healthy obese (MHO) and metabolically unhealthy obese (MUO). Untargeted fingerprinting, based on pattern recognition by template matching, is applied on single data streams and on fused data, obtained by combining raw signals from the two ionization energies (12 and 70 eV). Results indicate that at lower energy (i.e., 12 eV), the total signal intensity is one order of magnitude lower compared to the reference signal at 70 eV, but the ranges of variations for 2D peak responses is larger, extending the dynamic range. Fused data combine benefits from 70 eV and 12 eV resulting in more comprehensive coverage by sample fingerprints. Multivariate statistics, principal component analysis (PCA), and partial least squares discriminant analysis (PLS-DA) show quite good patient clustering, with total explained variance by the first two principal components (PCs) that increases from 54% at 70 eV to 59% at 12 eV and up to 71% for fused data. With PLS-DA, discriminant components are highlighted and putatively identified by comparing retention data and 70 eV spectral signatures. Within the most informative analytes, lactose is present in higher relative amount in saliva from MHO patients, whereas N-acetyl-D-glucosamine, urea, glucuronic acid γ-lactone, 2-deoxyribose, N-acetylneuraminic acid methyl ester, and 5-aminovaleric acid are more abundant in MUO patients. Visual feature fingerprinting is combined with pattern recognition algorithms to highlight metabolite variations between composite per-class images obtained by combining raw data from individuals belonging to different classes, i.e., MUO vs. MHO.Graphical abstract.


Assuntos
Cromatografia Gasosa/métodos , Saliva/metabolismo , Espectrometria de Massas por Ionização por Electrospray/métodos , Acetilglucosamina/análise , Algoritmos , Aminoácidos Neutros/análise , Cromatografia/métodos , Cromatografia Líquida de Alta Pressão , Cicloexanos/química , Desoxirribose/análise , Ésteres/análise , Lógica Fuzzy , Cromatografia Gasosa-Espectrometria de Massas/métodos , Glucuronatos/análise , Humanos , Lactose/análise , Masculino , Ácido N-Acetilneuramínico/análise , Obesidade/metabolismo , Valores de Referência , Solventes , Ureia/análise
12.
Nucleic Acids Res ; 49(1): 79-89, 2021 01 11.
Artigo em Inglês | MEDLINE | ID: mdl-33300028

RESUMO

The helical structures of DNA and RNA were originally revealed by experimental data. Likewise, the development of programs for modeling these natural polymers was guided by known structures. These nucleic acid polymers represent only two members of a potentially vast class of polymers with similar structural features, but that differ from DNA and RNA in the backbone or nucleobases. Xeno nucleic acids (XNAs) incorporate alternative backbones that affect the conformational, chemical, and thermodynamic properties of XNAs. Given the vast chemical space of possible XNAs, computational modeling of alternative nucleic acids can accelerate the search for plausible nucleic acid analogs and guide their rational design. Additionally, a tool for the modeling of nucleic acids could help reveal what nucleic acid polymers may have existed before RNA in the early evolution of life. To aid the development of novel XNA polymers and the search for possible pre-RNA candidates, this article presents the proto-Nucleic Acid Builder (https://github.com/GT-NucleicAcids/pnab), an open-source program for modeling nucleic acid analogs with alternative backbones and nucleobases. The torsion-driven conformation search procedure implemented here predicts structures with good accuracy compared to experimental structures, and correctly demonstrates the correlation between the helical structure and the backbone conformation in DNA and RNA.


Assuntos
Algoritmos , Modelos Químicos , Ácidos Nucleicos/química , Software , DNA/química , Desoxirribose/química , Estrutura Molecular , Conformação de Ácido Nucleico , RNA/química
13.
Biochem Biophys Res Commun ; 532(4): 662-667, 2020 11 19.
Artigo em Inglês | MEDLINE | ID: mdl-32907714

RESUMO

DNA triplex is a popular, higher-order structural arrangement with several biological importance. In the present article, we examined the impact of replacing regular deoxyribose sugar by conformationally locked sugar on the structure/stability of a DNA triplex. We individually modified single strands of DNA triplex (3'-5' strand/5'-3' strand) and observed the consequences in terms of the overall structural integrity and energetics using all-atom explicit-solvent Gaussian accelerated molecular dynamics simulations at biological salt concentration. As anticipated, the control DNA triplex maintained the structural integrity throughout the simulations. However, it is striking to note that a duplex evolved from both the modified systems (3'-5' modified triplex as well as 5'-3' modified triplex). The resultant duplexes in both cases contain a modified strand and a regular strand, whereas the third strand (regular ssDNA) left the binding site entirely. We observed that the modified ssDNA binds to the regular ssDNA with high affinities in both the hybrid duplexes (∼-64 kcal/mol), significantly higher than the regular ssDNA - regular ssDNA interaction (∼-52 kcal/mol). The remarkable binding of modified ssDNA to regular ssDNA can be utilized to design new antisense oligonucleotides, and the role of such modified oligonucleotides in anticancer therapy is foreseen.


Assuntos
DNA/química , Desoxirribose/química , Simulação de Dinâmica Molecular , Conformação de Ácido Nucleico
14.
Microvasc Res ; 131: 104035, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32593538

RESUMO

BACKGROUND: Delayed neovascularisation of tissue-engineered (TE) complex constructs is a major challenge that causes their failure post-implantation. Although significant progress has been made in the field of angiogenesis, ensuring rapid neovascularisation still remains a challenge. The use of pro-angiogenic agents is an effective approach to promote angiogenesis, and vascular endothelial growth factor (VEGF) has been widely studied both at the biological and molecular levels and is recognised as a key stimulator of angiogenesis. However, the exogenous use of VEGF in an uncontrolled manner has been shown to result in leaky, permeable and haemorrhagic vessels. Thus, researchers have been actively seeking alternative agents to upregulate VEGF production rather than exogenous use of VEGF in TE systems. We have previously revealed the potential of 2-deoxy-d-ribose (2dDR) as an alternative pro-angiogenic agent to induce angiogenesis and accelerates wound healing. However, to date, there is not any clear evidence on whether 2dDR influences the angiogenic cascade that involves VEGF. METHODS: In this study, we explored the angiogenic properties of 2dDR either by its direct application to human aortic endothelial cells (HAECs) or when released from commercially available alginate dressings and demonstrated that when 2dDR promotes angiogenesis, it also increases the VEGF production of HAECs. RESULTS: The VEGF quantification results suggested that VEGF production by HAECs was increased with 2dDR treatment but not with other sugars, including 2-deoxy-l-ribose (2dLR) and d-glucose (DG). The stability studies demonstrated that approximately 40-50% of the 2dDR had disappeared in the media over 14 days, either in the presence or absence of HAECs, and the reduction was higher when cells were present. The concentration of VEGF in the media also fell after day 4 associated with the reduction in 2dDR. CONCLUSION: This study suggests that 2dDR (but not other sugars tested in this study) stimulates angiogenesis by increasing the production of VEGF. We conclude 2dDR appears to be a practical and effective indirect route to upregulating VEGF for several days, leading to increased angiogenesis.


Assuntos
Indutores da Angiogênese/farmacologia , Membrana Corioalantoide/irrigação sanguínea , Desoxirribose/farmacologia , Células Endoteliais/efeitos dos fármacos , Neovascularização Fisiológica/efeitos dos fármacos , Fator A de Crescimento do Endotélio Vascular/metabolismo , Alginatos/química , Indutores da Angiogênese/química , Animais , Células Cultivadas , Embrião de Galinha , Preparações de Ação Retardada , Desoxirribose/química , Portadores de Fármacos , Estabilidade de Medicamentos , Células Endoteliais/metabolismo , Humanos , Transdução de Sinais , Regulação para Cima
15.
J Tissue Eng Regen Med ; 14(7): 973-988, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32473079

RESUMO

The absorption capacity of cotton dressings is a critical factor in their widespread use where they help absorb wound exudate. Cotton wax dressings, in contrast, are used for wounds where care is taken to avoid adhesion of dressings to sensitive wounds such as burn injuries. Accordingly, we explored the loading of 2-deoxy-D-ribose (2dDR), a small sugar, which stimulates angiogenesis and wound healing in normal and diabetic rats, into both types of dressings and measured the release of it over several days. The results showed that approximately 90% of 2dDR was released between 3 and 5 days when loaded into cotton dressings. For wax-coated cotton dressings, several methods of loading of 2dDR were explored. A strategy similar to the commercial wax coating methodology was found the best protocol which provided a sustained release over 5 days. Cytotoxicity analysis of 2dDR loaded cotton dressing showed that the dressing stimulated metabolic activity of fibroblasts over 7 days confirming the non-toxic nature of this sugar-loaded dressings. The results of the chick chorioallantoic membrane (CAM) assay demonstrated a strong angiogenic response to both 2dDR loaded cotton dressing and to 2dDR loaded cotton wax dressings. Both dressings were found to increase the number of newly formed blood vessels significantly when observed macroscopically and histologically. We conclude this study offers a simple approach to developing affordable wound dressings as both have the potential to be evaluated as pro-active dressings to stimulate wound healing in wounds where management of exudate or prevention of adherence to the wounds are clinical requirements.


Assuntos
Indutores da Angiogênese , Bandagens , Fibra de Algodão , Desoxirribose , Teste de Materiais , Neovascularização Fisiológica/efeitos dos fármacos , Indutores da Angiogênese/química , Indutores da Angiogênese/farmacologia , Animais , Embrião de Galinha , Membrana Corioalantoide/metabolismo , Desoxirribose/química , Desoxirribose/farmacologia , Diabetes Mellitus Experimental/metabolismo , Diabetes Mellitus Experimental/terapia , Camundongos , Células NIH 3T3 , Ratos , Cicatrização
16.
Med Hypotheses ; 142: 109754, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32438240

RESUMO

The recent global pandemic created by the Coronavirus SARS-CoV-2, started in Wuhan, China in December 2019, has generated panic, both in term of human death (4-5% of infected patients identified through testing) and the global economy. Human sufferings seem to be continuing, and it is not clear how long this will continue and how much more destruction it is going to cause until complete control is achieved. One of the most disturbing issues is Covid-19 treatment; although a large number of medications, previously used successfully with other viruses (including Chinese herbal medicines and anti-malaria drugs), are under consideration, there remain questions as to whether they can play a satisfactory role for this disease. Global attempts are ongoing to find the drugs for the treatment of this virus but none of the antiviral drugs used for treatment of other human viral infection is working and hence attempts to find new drugs are continuing. Here the author is proposing that 5-Fluorouracil (5-FU) which when used on its own is failing as an antiviral agent due to the removal of this compound by proof reading ability exceptionally found in Coronaviruses. The author here is proposing to test 5-FU in combination with a number of deoxynucleosides on animal models infected with this Covid-19. Should encouraging results ensue, therapies could then be tried on patients.


Assuntos
Infecções por Coronavirus/tratamento farmacológico , Desoxirribonucleosídeos/administração & dosagem , Desoxirribose/administração & dosagem , Fluoruracila/administração & dosagem , Pneumonia Viral/tratamento farmacológico , Monofosfato de Adenosina/administração & dosagem , Monofosfato de Adenosina/análogos & derivados , Alanina/administração & dosagem , Alanina/análogos & derivados , Betacoronavirus , COVID-19 , Cloroquina/administração & dosagem , Cloroquina/análogos & derivados , Ensaios Clínicos como Assunto , Esquema de Medicação , Sinergismo Farmacológico , Humanos , Inflamação/tratamento farmacológico , Modelos Teóricos , Pandemias , SARS-CoV-2
17.
Free Radic Biol Med ; 153: 17-25, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-32305647

RESUMO

Pancreatic ß-cells are vulnerable to oxidative stress, which promotes ß-cell failure in type 2 diabetes. System χc- is a sodium-independent, cystine/glutamate antiporter that mediates the exchange of extracellular l-cystine and intracellular l-glutamate. The import of l-cystine through this transporter is the rate-limiting step in the glutathione (GSH) biosynthesis pathway that plays a significant role in antioxidative defense. Previously, we reported that 2-deoxy-d-ribose (dRib) induces oxidative damage through GSH depletion in pancreatic ß-cells. In the current study, we elucidated the mechanism underlying the oxidative stress-induced ß-cell damage. We measured the intracellular l-[14C]cystine uptake, GSH content, reactive oxygen species (ROS) levels, cytotoxicity, and apoptosis in rat insulinoma cell line, RINm5F. Treatment of dRib decreased the intracellular l-[14C]cystine uptake and GSH content and increased the intracellular ROS levels, cytotoxicity, and apoptosis in a time- and dose-dependent manner. Conversely, 2-mercaptoethanol (2-ME), a cystine uptake enhancer, recovered the dRib-induced decrease in l-[14C]cystine uptake, GSH content, and cell viability in a Na+-independent manner. In the case of isolated islets, dRib dose-dependently decreased the intracellular l-[14C]cystine uptake and cell viability; however, dRib-induced cytotoxicity was completely recovered by adding N-acetyl cysteine (NAC). To confirm that system χc- mediates the oxidative stress-induced ß-cell damage, we overexpressed xCT (the substrate-specific subunit of system χc-) using a lentiviral vector in RINm5F cells. Overexpression of xCT fully recovered the dRib-induced decrease in l-[14C]cystine uptake and GSH content and prevented the dRib-induced increase in ROS levels, cytotoxicity, and apoptosis. The overexpression of xCT showed a protective effect against dRib-induced oxidative damage in RINm5F cells. Our study showed that dRib depletes intracellular GSH content through inhibition of cystine transport via system χc- in ß-cells.


Assuntos
Diabetes Mellitus Tipo 2 , Células Secretoras de Insulina , Sistema y+ de Transporte de Aminoácidos/genética , Sistema y+ de Transporte de Aminoácidos/metabolismo , Animais , Cistina/metabolismo , Desoxirribose/metabolismo , Diabetes Mellitus Tipo 2/metabolismo , Glutationa/metabolismo , Células Secretoras de Insulina/metabolismo , Estresse Oxidativo , Ratos , Ribose/metabolismo
18.
Curr Protein Pept Sci ; 21(9): 924-935, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32053073

RESUMO

The non-enzymatic glycosylation is a very common phenomenon in the physiological conditions which is mediated by distinct chemical entities containing reactive carbonyl species (RCS) and participates in the modification of various macromolecules particularly proteins. To date, various carbonyl species, i.e., glucose, fructose, D-ribose and methylglyoxal have been used frequently to assess the in-vitro non-enzymatic glycosylation. Similarly, 2'-Deoxyribose is one of the most abundant reducing sugar of the living organisms which forms the part of deoxyribonucleic acid and may react with proteins leading to the production of glycation intermediates, advanced glycation end products (AGEs) and highly reactive RCS. Thymidine phosphorylase derived degradation of thymidine contributes to the formation of 2'-Deoxyribose, therefore, acting as a major source of cellular 2'- Deoxyribose. Since albumin is a major serum protein which plays various roles including binding and transporting endogenous and exogenous ligands, it is more prone to be modified through different physiological modifiers; therefore, it may serve as a model protein for in-vitro experiments to study the effect of 2'Deoxyribose mediated modifications in the protein. In this study, Bovine Serum Albumin (BSA) was glycated with 50 and 100 mM 2'-Deoxyribose followed by examining secondary and tertiary structural modifications in BSA as compared to its native (unmodified) form by using various physicochemical techniques. We evident a significant modification in 2'-Deoxyribose-glycated BSA which was confirmed through increased hyperchromicity, keto amine moieties, carbonyl and hydroxymethylfurfural content, fluorescent AGEs, altered secondary structure conformers (α helix and ß sheets), band shift in the amide-I region and diminished free lysine and free arginine content. These modifications were reported to be higher in 100 mM 2'-Deoxyribose-glycated BSA than 50 mM 2'- Deoxyribose-glycated BSA. Our findings also demonstrated that the rate of glycation is positively affected by the increased concentration of 2'-Deoxyribose. The results of the performed study can be implied to uncover the phenomenon of serum protein damage caused by 2'-Deoxyribose leading towards diabetic complications and the number of AGE-related diseases.


Assuntos
Arginina/química , Desoxirribose/química , Furaldeído/análogos & derivados , Produtos Finais de Glicação Avançada/química , Lisina/química , Soroalbumina Bovina/química , Animais , Bovinos , Furaldeído/química , Glicosilação , Cinética , Oxirredução , Carbonilação Proteica , Estrutura Secundária de Proteína , Soluções , Espectrometria de Fluorescência
19.
Org Lett ; 22(6): 2167-2172, 2020 03 20.
Artigo em Inglês | MEDLINE | ID: mdl-32108487

RESUMO

A stereoselective nine-step synthesis of the potent HIV nucleoside reverse transcriptase translocation inhibitor (NRTTI) islatravir (EfdA, MK-8591) from 2-deoxyribose is described. Key findings include a diastereodivergent addition of an acetylide nucleophile to an enolizable ketone, a chemoselective ozonolysis of a terminal olefin and a biocatalytic glycosylation cascade that uses a unique strategy of byproduct precipitation to drive an otherwise-reversible transformation forward.


Assuntos
Desoxiadenosinas/síntese química , Desoxirribose/química , Alcinos/química , Inibidores da Transcriptase Reversa/síntese química , Silanos/química , Estereoisomerismo
20.
DNA Repair (Amst) ; 87: 102773, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-31945542

RESUMO

Free radical attack on C1' of deoxyribose forms the oxidized abasic (AP) site 2-deoxyribonolactone (dL). In vitro, dL traps the major base excision DNA repair enzyme DNA polymerase beta (Polß) in covalent DNA-protein crosslinks (DPC) via the enzyme's N-terminal lyase activity acting on 5'-deoxyribose-5-phosphate residues. We previously demonstrated formation of Polß-DPC in cells challenged with oxidants generating significant levels of dL. Proteasome inhibition under 1,10-copper-ortho-phenanthroline (CuOP) treatment significantly increased Polß-DPC accumulation and trapped ubiquitin in the DPC, with Polß accounting for 60-70 % of the total ubiquitin signal. However, the identity of the remaining oxidative ubiquityl-DPC remained unknown. In this report, we surveyed whether additional AP lyases are trapped in oxidative DPC in mammalian cells in culture. Poly(ADP-ribose) polymerase 1 (PARP1), Ku proteins, DNA polymerase λ (Polλ), and the bifunctional 8-oxoguanine DNA glycosylase 1 (OGG1), were all trapped in oxidative DPC in mammalian cells. We also observed significant trapping of Polλ, PARP1, and OGG1 in cells treated with the alkylating agent methylmethane sulfonate (MMS), in addition to dL-inducing agents. Ku proteins, in contrast, followed a pattern of trapping similar to that for Polß: MMS failed to produce Ku-DPC, while treatment with CuOP or (less effectively) H2O2 gave rise to significant Ku-DPC. Unexpectedly, NEIL1 and NEIL3 were trapped following H2O2 treatment, but not detectably in cells exposed to CuOP. The half-life of all the AP lyase-DPC ranged from 15-60 min, consistent with their active repair. Accordingly, CuOP treatment under proteasome inhibition significantly increased the observed levels of DPC in cultured mammalian cells containing PARP1, Ku protein, Polλ, and OGG1 proteins. As seen for Polß, blocking the proteasome led to the accumulation of DPC containing ubiquitin. Thus, the ubiquitin-dependent proteolytic mechanisms that control Polß-DPC removal may also apply to a broad array of oxidative AP lyase-DPC, preventing their toxic accumulation in cells.


Assuntos
Reparo do DNA , DNA Liase (Sítios Apurínicos ou Apirimidínicos)/metabolismo , Linhagem Celular Tumoral , DNA Glicosilases/metabolismo , DNA Polimerase beta/metabolismo , Desoxirribose , Humanos , Peróxido de Hidrogênio/metabolismo , Autoantígeno Ku/metabolismo , Oxirredução , Poli(ADP-Ribose) Polimerase-1/metabolismo
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...