Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 4.725
Filtrar
Mais filtros

Intervalo de ano de publicação
1.
Mol Cell Proteomics ; 22(7): 100589, 2023 07.
Artigo em Inglês | MEDLINE | ID: mdl-37301377

RESUMO

Spontaneous deamidation of asparaginyl residues in proteins, if not repaired or cleared, can set in motion a cascade that leads to deteriorated health. Previously, we have discovered that deamidated human serum albumin (HSA) is elevated in the blood of patients with Alzheimer's disease and other neurodegenerative diseases, while the level of endogenous antibodies against deamidated HSA is significantly diminished, creating an imbalance between the risk factor and the defense against it. Endogenous antibodies against deamidated proteins are still unexplored. In the current study, we employed the SpotLight proteomics approach to identify novel amino acid sequences in antibodies specific to deamidated HSA. The results provide new insights into the clearance mechanism of deamidated proteins, a possible avenue for prevention of neurodegeneration.


Assuntos
Proteômica , Albumina Sérica Humana , Humanos , Proteômica/métodos , Proteínas , Sequência de Aminoácidos , Anticorpos
2.
J Lipid Res ; 65(6): 100560, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38750995

RESUMO

Zinc is required for virtually all biological processes. In plasma, Zn2+ is predominantly transported by human serum albumin (HSA), which possesses two Zn2+-binding sites of differing affinities (sites A and B). Fatty acids (FAs) are also transported by HSA, with seven structurally characterized FA-binding sites (named FA1-FA7) known. FA binding inhibits Zn2+-HSA interactions, in a manner that can impact upon hemostasis and cellular zinc uptake, but the degree to which binding at specific FA sites contributes to this inhibition is unclear. Wild-type HSA and H9A, H67A, H247A, and Y150F/R257A/S287A (FA2-KO) mutant albumins were expressed in Pichia pastoris. Isothermal titration calorimetry studies revealed that the Zn2+-binding capacity at the high-affinity Zn2+ site (site A) was reduced in H67A and H247A mutants, with site B less affected. The H9A mutation decreased Zn2+ binding at the lower-affinity site, establishing His9 as a site B ligand. Zn2+ binding to HSA and H9A was compromised by palmitate, consistent with FA binding affecting site A. 13C-NMR experiments confirmed that the FA2-KO mutations prohibited FA binding at site FA2. Zn2+ binding to the FA2-KO mutant was unaffected by myristate, suggesting binding at FA2 is solely responsible for inhibition. Molecular dynamics studies identified the steric obstruction exerted by bound FA in site FA2, which impedes the conformational change from open (FA-loaded) to closed (FA-free) states, required for Zn2+ to bind at site A. The successful targeting of the FA2 site will aid functional studies exploring the interplay between circulating FA levels and plasma Zn2+ speciation in health and disease.


Assuntos
Ácidos Graxos , Albumina Sérica Humana , Zinco , Zinco/metabolismo , Humanos , Sítios de Ligação , Ácidos Graxos/metabolismo , Albumina Sérica Humana/metabolismo , Albumina Sérica Humana/química , Ligação Proteica
3.
Biochem Biophys Res Commun ; 722: 150168, 2024 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-38797156

RESUMO

Human serum albumin (HSA) is the most abundant plasma protein of the circulatory system. It is a multidomain, multifunctional protein that, combining diverse affinities and wide specificity, binds, stores, and transports a variety of biological compounds, pharmacores, and fatty acids. HSA is finding increasing uses in drug-delivery due to its ability to carry functionalized ligands and prodrugs. All this raises the question of competition for binding sites occupancy in case of multiple ligands, which in turn influences the protein structure/dynamic/function relationship and also has an impact on the biomedical applications. In this work, the effects of interactive binding of palmitic acid (PA), warfarin (War) and ibuprofen (Ibu) on the thermal stability of HSA were studied using DSC, ATR-FTIR, and EPR. PA is a high-affinity physiological ligand, while the two drugs are widely used for their anticoagulant (War) and anti-inflammatory (Ibu) efficacy, and are exogenous compounds that accommodate in the deputed drug site DS1 and DS2, respectively overlapping with some of the fatty acid binding sites. The results indicate that HSA acquires the highest thermal stability when it is fully saturated with PA. The binding of this physiological ligand does not hamper the binding of War or Ibu to the native state of the protein. In addition, the three ligands bind simultaneously, suggesting a synergic cooperative influence due to allosteric effects. The increased thermal stability subsequent to binary and multiple ligands binding moderates protein aggregation propensity and restricts protein dynamics. The biophysics findings provide interesting features about protein stability, aggregation, and dynamics in interaction with multiple ligands and are relevant in drug-delivery.


Assuntos
Ibuprofeno , Albumina Sérica Humana , Varfarina , Humanos , Sítios de Ligação , Ligação Competitiva , Ibuprofeno/química , Ibuprofeno/metabolismo , Ligantes , Ácido Palmítico/química , Ácido Palmítico/metabolismo , Ligação Proteica , Estabilidade Proteica/efeitos dos fármacos , Albumina Sérica Humana/metabolismo , Albumina Sérica Humana/química , Temperatura , Varfarina/química , Varfarina/metabolismo , Varfarina/farmacologia
4.
Small ; 20(6): e2306466, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-37775327

RESUMO

Proteins exhibit complex and diverse multi-dimensional structures, along with a wide range of functional groups capable of binding metal ions. By harnessing the unique characteristics of proteins, it is possible to enhance the synthesis of metal-organic frameworks (MOFs) and modify their morphology. Here, the utilization of biomineralized bovine serum albumin (BSA) protein as a template for synthesizing Mil-100 with superior microwave absorption (MA) properties is investigated. The multi-dimensional structure and abundant functional groups of biomineralized BSA protein make it an ideal candidate for guiding the synthesis of Mil-100 with intricate network structures. The BSA@Mil-100 synthesized using this method exhibits exceptional uniformity and monodispersity of nanocrystals. The findings suggest that the BSA protein template significantly influences the regulation of nanocrystal and microstructure formation of Mil-100, resulting in a highly uniform and monodisperse structure. Notably, the synthesized 2-BSA@Mil-100 demonstrates a high reflection loss value of -58 dB at 8.85 GHz, along with a maximum effective absorption bandwidth value of 6.79 GHz, spanning from 6.01 to 12.8 GHz. Overall, this study highlights the potential of utilizing BSA protein as a template for MOF synthesis, offering an effective strategy for the design and development of high-performance MA materials.

5.
Chembiochem ; 25(4): e202300550, 2024 02 16.
Artigo em Inglês | MEDLINE | ID: mdl-37873910

RESUMO

Diabetes mellitus, a metabolic disorder that is characterized by elevated blood glucose levels, is common throughout the world and its prevalence is steadily increasing. Early diagnosis and treatment are important to prevent acute complications and life-threatening long-term organ damage. Glycation sites in human serum albumin (HSA) are considered to be promising biomarkers of systemic glycemic status. This work aimed to develop a sensitive and clinically applicable ELISA for the quantification of glycation site Lys414 in HSA (HSAK414 ). The monoclonal antibodies (mAbs) were generated by immunizing mice with a glycated peptide. The established indirect ELISA based on mAb 50D8 (IgG1 isotype) yielded a limit of detection of 0.39 nmol/g HSA for HSAK414 with a linear dynamic range from 0.50 to 6.25 nmol/g glycated HSA. The inter- and intra-day assays with coefficients of variation less than 20 % indicated good assay performance and precision. Assay evaluation was based on plasma samples from diabetic and non-diabetic subjects with known HSAK414 glycation levels previously determined by LC-MS. Both data sets correlated very well. In conclusion, the generated mAb 50D8 and the established ELISA could be a valuable tool for the rapid quantitation of glycation site HSAK414 in plasma samples to evaluate its clinical relevance.


Assuntos
Diabetes Mellitus , Albumina Sérica , Humanos , Animais , Camundongos , Albumina Sérica/análise , Lisina , Anticorpos Monoclonais , Reação de Maillard , Albumina Sérica Humana/metabolismo , Ensaio de Imunoadsorção Enzimática
6.
Chembiochem ; : e202400329, 2024 Jun 26.
Artigo em Inglês | MEDLINE | ID: mdl-38926093

RESUMO

Photodynamic therapy (PDT) is a noninvasive approach to cancer treatment, wherein cell death is initiated by singlet oxygen (1O2) production via energy transfer from excited photosensitizers to ground-state O2. Effective clinical photosensitizers necessitate water solubility for in vivo administration. Hydrophobic dyes, such as phthalocyanines, cannot be used directly as photosensitizers. Herein, we synthesized a myoglobin-(human serum albumin) fusion protein reconstituted with zinc-phthalocyanine (ZnPc), termed ZnPcMb-HSA. The photophysical properties of ZnPcMb-HSA closely resemble those of ZnPc-substituted Mb. Notably, ZnPc dissociates from ZnPcMb-HSA and selectively accumulates within cancer cells, while the protein components remain extracellular. Treatment of four distinct cell lines with ZnPcMb-HSA, followed by red-light irradiation, effectively induced apoptosis. The half-maximal inhibitory concentrations (IC50) against these cancer cell lines ranged between 0.1-0.5 µM. Reconstituted Mb-HSA emerges as a promising carrier for transporting various water-insoluble porphyrinoid photosensitizer to target cancer cells in PDT applications.

7.
J Mol Recognit ; 37(2): e3075, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38191989

RESUMO

The binding of four alkaloids with human serum albumin (HSA) was investigated by isothermal titration calorimetry (ITC), spectroscopy and molecular docking techniques. The findings demonstrated that theophylline or caffeine can bind to HAS, respectively. The number of binding sites and binding constants are obtained. The binding mode is a static quenching process. The effects of steric hindrance, temperature, salt concentration and buffer solution on the binding indicated that theophylline and HSA have higher binding affinity than caffeine. The fluorescence and ITC results showed that the interaction between HSA and theophylline or caffeine is an entropy-driven spontaneous exothermic process. The hydrophobic force was the primary driving factor. The experimental results were consistent with the molecular docking data. Based on the molecular structures of the four alkaloids, steric hindrance might be a major factor in the binding between HSA and these four alkaloids. This study elucidates the mechanism of interactions between four alkaloids and HSA.


Assuntos
Alcaloides , Albumina Sérica Humana , Humanos , Albumina Sérica Humana/química , Simulação de Acoplamento Molecular , Cafeína , Teofilina , Espectrometria de Fluorescência , Termodinâmica , Sítios de Ligação , Calorimetria/métodos , Ligação Proteica , Dicroísmo Circular
8.
J Mol Recognit ; 37(4): e3084, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38596890

RESUMO

The binding of drugs to plasma proteins determines its fate within the physiological system, hence profound understanding of its interaction within the bloodstream is important to understand its pharmacodynamics and pharmacokinetics and thereby its therapeutic potential. In this regard, our work delineates the mechanism of interaction of Selumetinib (SEL), a potent anti-cancer drug showing excellent effect against multiple solid tumors, with plasma protein bovine serum albumin (BSA), using methods such as absorption, steady-state fluorescence, time-resolved, fluorescence resonance energy transfer, Fourier transform infrared spectra (FTIR), circular dichroism (CD), synchronous and 3D-fluorescence, salt fluorescence, molecular docking and molecular dynamic simulations. The BSA fluorescence intensity was quenched with increasing concentration of SEL which indicates interactions of SEL with BSA. Stern-Volmer quenching analysis and lifetime studies indicate the involvement of dynamic quenching. However, some contributions from the static quenching mechanism could not be ruled out unambiguously. The association constant was found to be 5.34 × 105 M-1 and it has a single binding site. The Förster distance (r) indicated probable energy transmission between the BSA and SEL. The positive entropy changes and enthalpy change indicate that the main interacting forces are hydrophobic forces, also evidenced by the results of molecular modeling studies. Conformation change in protein framework was revealed from FTIR, synchronous and 3D fluorescence and CD studies. Competitive binding experiments as well as docking studies suggest that SEL attaches itself to site I (subdomain IIA) of BSA where warfarin binds. Molecular dynamic simulations indicate the stability of the SEL-BSA complex. The association energy between BSA and SEL is affected in the presence of different metals differently.


Assuntos
Antineoplásicos , Benzimidazóis , Dicroísmo Circular , Simulação de Acoplamento Molecular , Simulação de Dinâmica Molecular , Ligação Proteica , Soroalbumina Bovina , Soroalbumina Bovina/química , Soroalbumina Bovina/metabolismo , Animais , Bovinos , Antineoplásicos/química , Antineoplásicos/farmacologia , Benzimidazóis/química , Benzimidazóis/farmacologia , Sítios de Ligação , Espectroscopia de Infravermelho com Transformada de Fourier , Transferência Ressonante de Energia de Fluorescência , Termodinâmica , Espectrometria de Fluorescência
9.
J Mol Recognit ; 37(3): e3076, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38366770

RESUMO

Tetramethrin (TMT) is a commonly used insecticide and has a carcinogenic and neurodegenerative effect on humans. The binding mechanism and toxicological implications of TMT to human serum albumin (HSA) were examined in this study employing a combination of biophysical and computational methods indicating moderate binding affinity and potential hepato and renal toxicity. Fluorescence quenching experiments showed that TMT binds to HSA with a moderate affinity, and the binding process was spontaneous and predominantly enthalpy-driven. Circular dichroism spectroscopy revealed that TMT binding did not induce any significant conformational changes in HSA, resulting in no changes in its alpha-helix content. The binding site and modalities of TMT interactions with HSA as computed by molecular docking and molecular dynamics simulations revealed that it binds to Sudlow site II of HSA via hydrophobic interactions through its dimethylcyclopropane carboxylate methyl propanyl group. The structural dynamics of TMT induce proper fit into the binding site creating increased and stabilizing interactions. Additionally, molecular mechanics-Poisson Boltzmann surface area calculations also indicated that non-polar and van der Waals were found to be the major contributors to the high binding free energy of the complex. Quantum mechanics (QM) revealed the conformational energies of the binding confirmation and the degree of deviation from the global minimum energy conformation of TMT. The results of this study provide a comprehensive understanding of the binding mechanism of TMT with HSA, which is important for evaluating the toxicity of this insecticide in humans.


Assuntos
Inseticidas , Piretrinas , Humanos , Ligação Proteica , Simulação de Acoplamento Molecular , Inseticidas/toxicidade , Espectrometria de Fluorescência , Albumina Sérica Humana/química , Sítios de Ligação , Termodinâmica , Dicroísmo Circular
10.
Mol Hum Reprod ; 30(3)2024 Feb 29.
Artigo em Inglês | MEDLINE | ID: mdl-38341666

RESUMO

To become fertile, mammalian sperm are required to undergo capacitation in the female tract or in vitro in defined media containing ions (e.g. HCO3 -, Ca2+, Na+, and Cl-), energy sources (e.g. glucose, pyruvate) and serum albumin (e.g. bovine serum albumin (BSA)). These different molecules initiate sequential and concomitant signaling pathways, leading to capacitation. Physiologically, capacitation induces changes in the sperm motility pattern (e.g. hyperactivation) and prepares sperm for the acrosomal reaction (AR), two events required for fertilization. Molecularly, HCO3 - activates the atypical adenylyl cyclase Adcy10 (aka sAC), increasing cAMP and downstream cAMP-dependent pathways. BSA, on the other hand, induces sperm cholesterol release as well as other signaling pathways. How these signaling events, occurring in different sperm compartments and with different kinetics, coordinate among themselves is not well established. Regarding the AR, recent work has proposed a role for glycogen synthase kinases (GSK3α and GSK3ß). GSK3α and GSK3ß are inactivated by phosphorylation of residues Ser21 and Ser9, respectively, in their N-terminal domain. Here, we present evidence that GSK3α (but not GSK3ß) is present in the anterior head and that it is regulated during capacitation. Interestingly, BSA and HCO3 - regulate GSK3α in opposite directions. While BSA induces a fast GSK3α Ser21 phosphorylation, HCO3 - and cAMP-dependent pathways dephosphorylate this residue. We also show that the HCO3--induced Ser21 dephosphorylation is mediated by hyperpolarization of the sperm plasma membrane potential (Em) and by intracellular pH alkalinization. Previous reports indicate that GSK3 kinases mediate the progesterone-induced AR. Here, we show that GSK3 inhibition also blocks the Ca2+ ionophore ionomycin-induced AR, suggesting a role for GSK3 kinases downstream of the increase in intracellular Ca2+ needed for this exocytotic event. Altogether, our data indicate a temporal and biphasic GSK3α regulation with opposite actions of BSA and HCO3 -. Our results also suggest that this regulation is needed to orchestrate the AR during sperm capacitation.


Assuntos
Quinase 3 da Glicogênio Sintase , Soroalbumina Bovina , Capacitação Espermática , Animais , Feminino , Masculino , Camundongos , Cálcio/metabolismo , AMP Cíclico/metabolismo , Quinase 3 da Glicogênio Sintase/genética , Quinase 3 da Glicogênio Sintase/metabolismo , Glicogênio Sintase Quinase 3 beta/metabolismo , Mamíferos , Fosforilação , Sêmen/metabolismo , Soroalbumina Bovina/farmacologia , Soroalbumina Bovina/metabolismo , Motilidade dos Espermatozoides , Espermatozoides/metabolismo
11.
J Transl Med ; 22(1): 454, 2024 May 13.
Artigo em Inglês | MEDLINE | ID: mdl-38741158

RESUMO

BACKGROUND: Glycosylation is an enzyme-catalyzed post-translational modification that is distinct from glycation and is present on a majority of plasma proteins. N-glycosylation occurs on asparagine residues predominantly within canonical N-glycosylation motifs (Asn-X-Ser/Thr) although non-canonical N-glycosylation motifs Asn-X-Cys/Val have also been reported. Albumin is the most abundant protein in plasma whose glycation is well-studied in diabetes mellitus. However, albumin has long been considered a non-glycosylated protein due to absence of canonical motifs. Albumin contains two non-canonical N-glycosylation motifs, of which one was recently reported to be glycosylated. METHODS: We enriched abundant serum proteins to investigate their N-linked glycosylation followed by trypsin digestion and glycopeptide enrichment by size-exclusion or mixed-mode anion-exchange chromatography. Glycosylation at canonical as well as non-canonical sites was evaluated by liquid chromatography-tandem mass spectrometry (LC-MS/MS) of enriched glycopeptides. Deglycosylation analysis was performed to confirm N-linked glycosylation at non-canonical sites. Albumin-derived glycopeptides were fragmented by MS3 to confirm attached glycans. Parallel reaction monitoring was carried out on twenty additional samples to validate these findings. Bovine and rabbit albumin-derived glycopeptides were similarly analyzed by LC-MS/MS. RESULTS: Human albumin is N-glycosylated at two non-canonical sites, Asn68 and Asn123. N-glycopeptides were detected at both sites bearing four complex sialylated glycans and validated by MS3-based fragmentation and deglycosylation studies. Targeted mass spectrometry confirmed glycosylation in twenty additional donor samples. Finally, the highly conserved Asn123 in bovine and rabbit serum albumin was also found to be glycosylated. CONCLUSIONS: Albumin is a glycoprotein with conserved N-linked glycosylation sites that could have potential clinical applications.


Assuntos
Albuminas , Glicoproteínas , Glicosilação , Animais , Bovinos , Humanos , Albuminas/metabolismo , Sequência de Aminoácidos , Cromatografia Líquida , Glicopeptídeos/metabolismo , Glicopeptídeos/química , Glicoproteínas/metabolismo , Glicoproteínas/química , Dados de Sequência Molecular , Espectrometria de Massas em Tandem
12.
Oncology ; 102(7): 604-610, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38198783

RESUMO

INTRODUCTION: The risk of thromboembolic events developing limits the dose of antiangiogenic agents, thereby reducing their efficacy. This retrospective study therefore sought to identify predictors for the development of antiangiogenic agent-induced thromboembolic events and to elucidate whether differences in the likelihood of thromboembolic events exist between different antiangiogenic agents or cancer types, to guide future strategies for optimizing safety, efficacy, and quality of life in patients receiving chemotherapy. METHODS: This study retrospectively investigated 468 cancer patients who received chemotherapy with bevacizumab, ramucirumab, or aflibercept at our outpatient chemotherapy center between December 2016 and April 2022. Variables related to the development of thromboembolic events were extracted from the medical records, and multivariate logistic regression analysis was performed to identify predictors for the development of thromboembolic events. The Wilcoxon/Kruskal-Wallis test was used to detect significant differences between groups. RESULTS: Significant factors included serum albumin level (odds ratio [OR] = 0.363, 95% confidence interval [CI] = 0.193-0.685; p = 0.0017) and diabetes mellitus (OR = 5.356, 95% CI = 1.711-16.769; p = 0.0039). Renin-angiotensin system inhibitors (OR = 0.307) had low OR, although it was not significant. No difference in the development of thromboembolic events was evident between cancer types (p = 0.0781), but differences were identified between the three antiangiogenic agents (p = 0.0132). Ramucirumab was associated with a lower likelihood of thromboembolic events. CONCLUSION: Serum albumin level and diabetes mellitus were identified as significant predictors for the development of antiangiogenic agent-induced thromboembolic events. In addition, the likelihood of thromboembolic events did not differ between cancer types but differed between antiangiogenic agents.


Assuntos
Inibidores da Angiogênese , Anticorpos Monoclonais Humanizados , Bevacizumab , Neoplasias , Ramucirumab , Receptores de Fatores de Crescimento do Endotélio Vascular , Proteínas Recombinantes de Fusão , Tromboembolia , Humanos , Bevacizumab/efeitos adversos , Bevacizumab/administração & dosagem , Estudos Retrospectivos , Masculino , Feminino , Pessoa de Meia-Idade , Receptores de Fatores de Crescimento do Endotélio Vascular/antagonistas & inibidores , Neoplasias/tratamento farmacológico , Tromboembolia/induzido quimicamente , Tromboembolia/epidemiologia , Idoso , Anticorpos Monoclonais Humanizados/efeitos adversos , Anticorpos Monoclonais Humanizados/administração & dosagem , Anticorpos Monoclonais Humanizados/uso terapêutico , Inibidores da Angiogênese/efeitos adversos , Inibidores da Angiogênese/uso terapêutico , Inibidores da Angiogênese/administração & dosagem , Proteínas Recombinantes de Fusão/efeitos adversos , Proteínas Recombinantes de Fusão/administração & dosagem , Adulto , Idoso de 80 Anos ou mais , Fatores de Risco
13.
Arch Biochem Biophys ; 757: 110038, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38750920

RESUMO

Oxidized albumin is considered a short-term biomarker of oxidative stress and its measurement in blood contributes to evaluate the impact of diseases, drugs, dialytic treatments, physical activity, environmental contaminants etc. on the red-ox balance of humans as well as of other mammalians. Nevertheless, the most common methods for quantifying the oxidized and reduced albumins are costly and time-consuming. Furthermore, there is a dearth of information regarding the proper ways to store human serum or plasma samples in order to prevent inaccurate quantification of these various albumin forms. This paper explores these aspects and proposes a few spectrophotometric assay procedures which make the quantitation of oxidized and reduced albumin very fast, precise and un-expensive in various mammals.


Assuntos
Oxirredução , Albumina Sérica , Animais , Humanos , Biomarcadores/sangue , Mamíferos/sangue , Estresse Oxidativo , Albumina Sérica/análise , Espectrofotometria
14.
Chemphyschem ; 25(2): e202300505, 2024 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-38009440

RESUMO

Proteins can alter their shape when interacting with a surface. This study explores how bovine serum albumin (BSA) modifies structurally when it adheres to a gold surface, depending on the protein concentration and pH. We verified that the gold surface induces significant structural modifications to the BSA molecule using circular dichroism, infrared spectroscopy, and atomic force microscopy. Specifically, adsorbed molecules displayed increased levels of disordered structures and ß-turns, with fewer α-helices than the native structure. MP-SPR spectroscopy demonstrated that the protein molecules preferred a planar orientation during adsorption. Molecular dynamics simulations revealed that the interaction between cysteines exposed to the outside of the molecule and the gold surface was vital, especially at pH=3.5. The macroscopic properties of the protein film observed by AFM and contact angles confirm the flexible nature of the protein itself. Notably, structural transformation is joined with the degree of hydration of protein layers.


Assuntos
Ouro , Soroalbumina Bovina , Ouro/química , Soroalbumina Bovina/química , Propriedades de Superfície , Estrutura Secundária de Proteína , Dicroísmo Circular , Adsorção
15.
Mol Pharm ; 21(5): 2198-2211, 2024 May 06.
Artigo em Inglês | MEDLINE | ID: mdl-38625037

RESUMO

Micellar drug delivery systems (MDDS) for the intravenous administration of poorly soluble drugs have great advantages over alternative formulations in terms of the safety of their excipients, storage stability, and straightforward production. A classic example is mixed micelles of glycocholate (GC) and lecithin, both endogenous substances in human blood. What limits the use of MDDS is the complexity of the transitions after injection. In particular, as the MDDS disintegrate partially or completely after injection, the drug has to be transferred safely to endogenous carriers in the blood, such as human serum albumin (HSA). If this transfer is compromised, the drug might precipitate─a process that needs to be excluded under all circumstances. The key question of this paper is whether the high local concentration of GC at the moment and site of MDDS dissolution might transiently saturate HSA binding sites and, hence, endanger quick drug transfer. To address this question, we have used a new approach, which is time-resolved fluorescence spectroscopy of the single tryptophan in HSA, Trp-214, to characterize the competitive binding of GC and the drug substitute anilinonaphthalenesulfonate (ANS) to HSA. Time-resolved fluorescence of Trp-214 showed important advantages over established methods for tackling this problem. ANS has been the standard "model drug" to study albumin binding for decades, given its structural similarity to the class of naphthalene-containing acidic drugs and the fact that it is displaced from HSA by numerous drugs (which presumably bind to the same sites). Our complex global fit uses the critical approximation that the average lifetimes behave similarly to a single lifetime, but the resulting errors are found to be moderate and the results provide a convincing explanation of the, at first glance, counterintuitive behavior. Accordingly, and largely in line with the literature, we observed two types of sites binding ANS at HSA: 3 type A, rather peripheral, and 2 type B, likely more central sites. The latter quench Trp-214 by Förster Resonance Energy Transfer (FRET) with a rate constant of ≈0.4 ns-1 per ANS. Adding millimolar concentrations of GC displaces ANS from the A sites but not from B sites. At incomplete ANS saturation, this causes a GC-induced translocation of ANS from A to the more FRET-active B sites. This leads to the apparent paradox that the partial displacement of ANS from HSA increases its quenching effect on Trp-214. The most important conclusion is that (ANS-like) drugs cannot be displaced from the type-B sites, and consequently, drug transfer to these sites is not impaired by competitive binding of GC in the vicinity of a dissolving micelle. The second conclusion is that for unbound GC above the CMC (9 mM), ANS equilibrates between HSA and GC micelles but with a strong preference for free sites on HSA. That means that even persisting micelles would lose their cargo readily once exposed to HSA. For all MDDS sharing this property, targeted drug delivery approaches involving them as the nanocarrier would be pointless.


Assuntos
Sistemas de Liberação de Medicamentos , Micelas , Albumina Sérica Humana , Tensoativos , Humanos , Sítios de Ligação , Sistemas de Liberação de Medicamentos/métodos , Albumina Sérica Humana/química , Albumina Sérica Humana/metabolismo , Tensoativos/química , Espectrometria de Fluorescência , Naftalenossulfonato de Anilina/química , Ligação Proteica
16.
Gynecol Oncol ; 180: 126-131, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-38091771

RESUMO

OBJECTIVE: We aimed to examine the interplay between frailty and nutritional status on 90-day mortality after primary cytoreductive surgery (PCS) for ovarian cancer (OC). METHODS: Patients with OC who underwent PCS from 1/2/2006-4/30/2018 at a single institution were identified. Frailty index (FI) includes 30 items and is calculated summing across all the item scores and dividing by the total; frailty was defined as FI ≥0.15. Nutritional status was considered impaired when preoperative serum albumin was <3.5 g/dL. Logistic regression was used to analyze the association between FI (continuous) and albumin status (binary) and 90-day postoperative mortality. RESULTS: A total of 533 patients (mean age, 64.4 years) were included, the majority were stage IIIC disease and serous histology. Albumin was <3.5 g/dL in 87 patients (16.3%) and 113 patients (21.2%) were considered frail. Median FI was 0.07 (IQR 0.03, 0.13). Postoperative 90-day mortality occurred in 24 patients (4.5%). Mortality within 90 days was higher amongst patients with low albumin (12/87, 13.8%), regardless of frailty status (13.8% [9/65] non-frail and 13.6% [3/22] frail patients). Ninety-day mortality in patients with normal albumin (n = 446) was over twice as likely in frail versus non-frail patients (5.5% [5/91] vs. 2.0% [7/355], respectively, p = 0.08). A model to assess 90-day mortality that included both FI and low albumin significantly improved the overall discrimination compared to low albumin alone (AUC 0.76 vs. 0.68 p = 0.03). CONCLUSION: Our findings suggest that frailty and nutrition are both related to 90-day mortality. Preoperative interventions to improve functional and nutritional characteristics are needed.


Assuntos
Fragilidade , Neoplasias Ovarianas , Humanos , Feminino , Pessoa de Meia-Idade , Idoso , Fragilidade/complicações , Procedimentos Cirúrgicos de Citorredução , Estado Nutricional , Neoplasias Ovarianas/cirurgia , Albuminas , Idoso Fragilizado , Avaliação Geriátrica
17.
Eur Radiol ; 34(4): 2212-2222, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-37673964

RESUMO

OBJECTIVES: To compare the efficacy of computed tomography volumetry (CTV), technetium99m galactosyl-serum-albumin (99mTc-GSA) scintigraphy, and gadolinium-ethoxybenzyl-diethylenetriamine-pentaacetic-acid-enhanced MRI (EOB-MRI) in estimating the liver fibrosis (LF) stage in patients undergoing liver resection. METHODS: This retrospective study included 91 consecutive patients who had undergone preoperative dynamic CT and 99mTc-GSA scintigraphy. EOB-MRI was performed in 76 patients. CTV was used to measure the total liver volume (TLV), spleen volume (SV), normalised to the body surface area (BSA), and liver-to-spleen volume ratio (TLV/SV). 99mTc-GSA scintigraphy provided LHL15, HH15, and GSA indices. The liver-to-spleen ratio (LSR) was calculated in the hepatobiliary phase of EOB-MRI. Hyaluronic acid and type 4 collagen levels were measured in 65 patients. Logistic regression and receiver operating characteristic (ROC) analyses were performed to identify useful parameters for estimating the LF stage and laboratory data. RESULTS: According to the multivariable logistic regression analysis, SV/BSA (odds ratio [OR], 1.01; 95% confidence interval [CI], 1.003-1.02; p = 0.011), LSR (OR, 0.06; 95%CI, 0.004-0.70; p = 0.026), and hyaluronic acid (OR, 1.01; 95%CI, 1.001-1.02; p = 0.024) were independent variables for severe LF (F3-4). Combined SV/BSA, LSR, and hyaluronic acid correctly estimated severe LF, with an AUC of 0.91, which was significantly larger than the AUCs of the GSA index (AUC = 0.84), SV/BSA (AUC = 0.83), or LSR (AUC = 0.75) alone. CONCLUSIONS: Combined CTV, EOB-MRI, and hyaluronic acid analyses improved the estimation accuracy of severe LF compared to CTV, EOB-MRI, or 99mTc-GSA scintigraphy individually. CLINICAL RELEVANCE STATEMENT: The combined analysis of spleen volume on CT volumetry, liver-to-spleen ratio on gadolinium-ethoxybenzyl-diethylenetriamine-pentaacetic-acid-enhanced MRI, and hyaluronic acid can identify severe liver fibrosis associated with a high risk of liver failure after hepatectomy and recurrence in patients with hepatocellular carcinoma. KEY POINTS: • Spleen volume of CT volumetry normalised to the body surface area, liver-to-spleen ratio of EOB-MRI, and hyaluronic acid were independent variables for liver fibrosis. • CT volumetry and EOB-MRI enable the detection of severe liver fibrosis, which may correlate with post-hepatectomy liver failure and complications. • Combined CT volumetry, gadolinium-ethoxybenzyl-diethylenetriamine-pentaacetic-acid-enhanced MRI (EOB-MRI), and hyaluronic acid analyses improved the estimation of severe liver fibrosis compared to technetium99m galactosyl-serum-albumin scintigraphy.


Assuntos
Falência Hepática , Neoplasias Hepáticas , Poliaminas , Humanos , Tecnécio , Albumina Sérica , Estudos Retrospectivos , Gadolínio , Ácido Hialurônico , Compostos Radiofarmacêuticos , Neoplasias Hepáticas/diagnóstico por imagem , Testes de Função Hepática , Fígado/diagnóstico por imagem , Fígado/cirurgia , Fígado/patologia , Cintilografia , Agregado de Albumina Marcado com Tecnécio Tc 99m , Pentetato de Tecnécio Tc 99m , Cirrose Hepática/patologia , Hepatectomia , Tomografia Computadorizada por Raios X , Imageamento por Ressonância Magnética/métodos
18.
Diabetes Obes Metab ; 26(6): 2239-2247, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38454743

RESUMO

AIM: The ingestion of Lactiplantibacillus plantarum OLL2712 (OLL2712) cells has been shown to improve glucose metabolism by suppressing chronic inflammation in murine models and clinical studies. This study aimed to clarify the effect of OLL2712 on glycaemic control in healthy adults with prediabetes. MATERIALS AND METHODS: The study was a randomized, double-blind, placebo-controlled, parallel-group design. Adult participants with prediabetes [n = 148, glycated haemoglobin (HbA1c) range: 5.6%-6.4%, age range: 20-64 years] were assigned randomly to placebo or OLL2712 groups (n = 74/group) and administered daily for 12 weeks either conventional yogurt or yogurt containing >5 × 109 heat-treated OLL2712 cells, respectively. In addition, the participants were followed for 8 weeks after the discontinuation of either yogurt. The primary outcome was the changes in HbA1c levels at weeks 12 and 16 by analysis of covariance. RESULTS: The levels of HbA1c and glycoalbumin decreased significantly in both groups at week 12 in comparison with those at week 0, but only in the OLL2712 group at week 16. HbA1c levels decreased significantly at weeks 12 and 16 in the OLL2712 group in comparison with the placebo group (p = .014 and p = .006, respectively). No significant inter- and intragroup differences in HbA1c levels were observed at week 20. CONCLUSIONS: The ingestion of OLL2712 prevents the deterioration of glycaemic control and maintains the HbA1c levels within the normal range in adults with prediabetes; yogurt probably exhibits similar effects, which may contribute to reducing the risk of developing type 2 diabetes.


Assuntos
Hemoglobinas Glicadas , Controle Glicêmico , Estado Pré-Diabético , Probióticos , Iogurte , Humanos , Método Duplo-Cego , Probióticos/uso terapêutico , Probióticos/administração & dosagem , Estado Pré-Diabético/dietoterapia , Estado Pré-Diabético/sangue , Estado Pré-Diabético/terapia , Adulto , Masculino , Pessoa de Meia-Idade , Feminino , Hemoglobinas Glicadas/análise , Hemoglobinas Glicadas/metabolismo , Controle Glicêmico/métodos , Glicemia/metabolismo , Adulto Jovem , Lactobacillus plantarum
19.
BMC Neurol ; 24(1): 35, 2024 Jan 19.
Artigo em Inglês | MEDLINE | ID: mdl-38243235

RESUMO

BACKGROUND: The relationship between cerebrospinal fluid pressure (CSFP) and cognition has received little research attention. The purpose of this study was to explore the relationship between CSFP and cognition in patients with Alzheimer's disease (AD) and patients with Lewy body dementia (LBD). METHOD: We included 178 participants, including 137 patients with AD and 41 patients with LBD (including dementia with Lewy bodies (DLBs) and Parkinson's disease dementia (PDD)). CSFP was measured by lumbar puncture, and a patient-reported history and laboratory test data were collected. Logistic and linear regression analyses were used to evaluate the associations between CSFP and cognition, the cerebrospinal fluid (CSF) / serum albumin ratio (Qalb), and CSF biomarkers of AD. RESULTS: The mean age of the included patients was 63.58 ± 8.77 years old, and the mean CSFP was 121 ± 33.72 mmH2O. A total of 76.9% of the patients had a CSFP distribution of [90-170) mmH2O, 46 patients (25.8%) had severe dementia, 83 patients (46.6%) had moderate dementia, 28 patients (15.7%) had mild dementia, and 21 patients (11.8%) had mild cognitive impairment (MCI) (including 16 patients with MCI due to AD and 5 patients with MCI due to LBD). In all patients (p value < 0.001) and in patients with AD (p value = 0.01), the mean cerebrospinal fluid pressure (CSFP) was higher in patients with MCI than in patients with dementia. In multivariate analysis, in all patients (OR: 6.37, 95% confidential interval (CI): 1.76-23.04, p = 0.005) and patients with AD (odds ratio (OR): 5.43, 95% CI: 1.41-20.87, p = 0.005), a CSFP in the lowest quartile ([50-90) mmH2O) was associated with a higher level of severe dementia than a CSFP in the highest quartile ([170-210) mmH2O). In addition, there was a significant linear correlation between CSFP and the Mini-Mental State Examination (MMSE) score in all patients with dementia (r = 0.43, p = 0.04, Durbin-Watson test (D-W test) = 0.75). CONCLUSION: In patients with AD, the mean cerebrospinal fluid pressure was higher in patients with MCI than in patients with dementia, and the decrease in CSFP was related to a more serious dementia level. However, no such relationship was found in patients with LBD.


Assuntos
Doença de Alzheimer , Disfunção Cognitiva , Demência , Doença por Corpos de Lewy , Doença de Parkinson , Humanos , Pessoa de Meia-Idade , Idoso , Doença de Alzheimer/líquido cefalorraquidiano , Demência/complicações , Doença por Corpos de Lewy/complicações , Proteínas tau/líquido cefalorraquidiano , Doença de Parkinson/complicações , Cognição , Disfunção Cognitiva/diagnóstico , Biomarcadores/líquido cefalorraquidiano , Pressão do Líquido Cefalorraquidiano , Peptídeos beta-Amiloides/líquido cefalorraquidiano
20.
Nanotechnology ; 35(18)2024 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-38295400

RESUMO

Albumin is a vital blood protein responsible for transporting metabolites and drugs throughout the body and serves as a potential biomarker for various medical conditions, including inflammatory, cardiovascular, and renal issues. This report details the fabrication of Ni-metal organic framework/SnS2nanocomposite modified nickel foam electrochemical sensor for highly sensitive and selective non enzymatic detection of albumin in simulated human blood serum samples. Ni-metal organic framework/SnS2nanocomposite was synthesized using solvothermal technique by combining Ni-metal-organic framework (MOF) with conductive SnS2leading to the formation of a highly porous material with reduced toxicity and excellent electrical conductivity. Detailed surface morphology and chemical bonding of the Ni-MOF/SnS2nanocomposite was studied using scanning electron microscopy, transmission electron microscopy, Fourier transform infra-red, and Raman analysis. The Ni-MOF/SnS2nanocomposite coated on Ni foam electrode demonstrated outstanding electrochemical performance, with a low limit of detection (0.44µM) and high sensitivity (1.3µA/pM/cm2) throughout a broad linear range (100 pM-10 mM). The remarkable sensor performance is achieved through the synthesis of a Ni-MOF/SnS2nanocomposite, enhancing electrocatalytic activity for efficient albumin redox reactions. The enhanced performance can be attributed due to the structural porosity of nickel foam and Ni-metal organic framework, which favours increased surface area for albumin interaction. The presence of SnS2shows stability in acidic and neutral solutions due to high surface to volume ratio which in turn improves sensitivity of the sensing material. The sensor exhibited commendable selectivity, maintaining its performance even when exposed to potential interfering substances like glucose, ascorbic acid, K+, Na+, uric acid, and urea. The sensor effectively demonstrates its accuracy in detecting albumin in real samples, showcasing substantial recovery percentages of 105.1%, 110.28%, and 91.16%.


Assuntos
Estruturas Metalorgânicas , Nanocompostos , Humanos , Estruturas Metalorgânicas/química , Níquel/química , Soro , Eletrodos , Técnicas Eletroquímicas
SELEÇÃO DE REFERÊNCIAS
Detalhe da pesquisa