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1.
Horm Metab Res ; 55(8): 536-545, 2023 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-37192655

RESUMO

To evaluate safety and therapeutic effect along 12 months of allogenic adipose tissue-derived stromal/stem cells (ASCs) transplantation with cholecalciferol (VITD) in patients with recent-onset type 1 diabetes (T1D). Prospective, phase II, open trial, pilot study in which patients with recent onset T1D received ASCs (1xKgx106 cells) and VITD 2000UI/day for 12 months (group 1) and were compared to controls with standard insulin therapy (group 2). Adverse events, C-peptide area under the curve (CPAUC), insulin dose, HbA1c and frequency of FoxP3+ in CD4+ or CD8+ T-cells(flow cytometry) were evaluated at baseline(T0), after 3(T3), 6(T6) and 12 months(T12). Eleven patients completed follow up (7:group 1;4:group 2). Group 1 had lower insulin requirement at T3(0.24±0.18vs0.53±0.23UI/kg,p=0.04), T6(0.24±0.15vs0.66±0.33 UI/kg,p=0.04) and T12(0.39±0.15vs0.74±0.29 UI/Kg,p=0.04).HbA1c was lower at T6 (50.57±8.56vs72.25±10.34 mmol/mol,p=0.01), without differences at T12 (57.14±11.98 in group 1 vs. 73.5±14.57 mmol/min in group 2, p=0.16). CPAUC was not significantly different between groups at T0(p=0.07), higher in group 1 at T3(p=0.04) and T6(p=0.006), but similar at T12(p=0.23). IDAA1c was significantly lower in group 1 than group 2 at T3,T6 and T12 (p=0.006, 0.006 and 0.042, respectively). IDDA1c was inversely correlated to FoxP3 expression in CD4 and CD8+ T cells at T6 (p<0.001 and p=0.01, respectively). In group 1, one patient had recurrence of a benign teratoma that was surgically removed, not associated to the intervention. ASCs with VITD without immunosuppression were safe and associated lower insulin requirements, better glycemic control, and transient better pancreatic function in recent onset T1D, but the potential benefits were not sustained.


Assuntos
Diabetes Mellitus Tipo 1 , Humanos , Diabetes Mellitus Tipo 1/terapia , Colecalciferol/uso terapêutico , Hemoglobinas Glicadas , Projetos Piloto , Estudos Prospectivos , Seguimentos , Insulina/metabolismo , Tecido Adiposo/metabolismo , Suplementos Nutricionais , Células-Tronco/metabolismo , Fatores de Transcrição Forkhead
2.
Angew Chem Int Ed Engl ; 59(30): 12331-12336, 2020 07 20.
Artigo em Inglês | MEDLINE | ID: mdl-31815351

RESUMO

Anaerobic microorganisms of the Geobacter genus are effective electron sources for the synthesis of nanoparticles, for bioremediation of polluted water, and for the production of electricity in fuel cells. In multistep reactions, electrons are transferred via iron/heme cofactors of c-type cytochromes from the inner cell membrane to extracellular metal ions, which are bound to outer membrane cytochromes. We measured electron production and electron flux rates to 5×105  e s-1 per G. sulfurreducens. Remarkably, these rates are independent of the oxidants, and follow zero order kinetics. It turned out that the microorganisms regulate electron flux rates by increasing their Fe2+ /Fe3+ ratios in the multiheme cytochromes whenever the activity of the extracellular metal oxidants is diminished. By this mechanism the respiration remains constant even when oxidizing conditions are changing. This homeostasis is a vital condition for living systems, and makes G. sulfurreducens a versatile electron source.

3.
Biochim Biophys Acta Bioenerg ; 1859(8): 619-630, 2018 08.
Artigo em Inglês | MEDLINE | ID: mdl-29777686

RESUMO

The bacterium Geobacter sulfurreducens can transfer electrons to quinone moieties of humic substances or to anthraquinone-2,6-disulfonate (AQDS), a model for the humic acids. The reduced form of AQDS (AH2QDS) can also be used as energy source by G. sulfurreducens. Such bidirectional utilization of humic substances confers competitive advantages to these bacteria in Fe(III) enriched environments. Previous studies have shown that the triheme cytochrome PpcA from G. sulfurreducens has a bifunctional behavior toward the humic substance analogue. It can reduce AQDS but the protein can also be reduced by AH2QDS. Using stopped-flow kinetic measurements we were able to demonstrate that other periplasmic members of the PpcA-family in G. sulfurreducens (PpcB, PpcD and PpcE) also showed the same behavior. The extent of the electron transfer is thermodynamically controlled favoring the reduction of the cytochromes. NMR spectra recorded for 13C,15N-enriched samples in the presence increasing amounts of AQDS showed perturbations in the chemical shift signals of the cytochromes. The chemical shift perturbations on cytochromes backbone NH and 1H heme methyl signals were used to map their interaction regions with AQDS, showing that each protein forms a low-affinity binding complex through well-defined positive surface regions in the vicinity of heme IV (PpcB, PpcD and PpcE) and I (PpcE). Docking calculations performed using NMR chemical shift perturbations allowed modeling the interactions between AQDS and each cytochrome at a molecular level. Overall, the results obtained provided important structural-functional relationships to rationalize the microbial respiration of humic substances in G. sulfurreducens.


Assuntos
Citocromos/metabolismo , Elétrons , Geobacter/metabolismo , Heme/metabolismo , Substâncias Húmicas , Sequência de Aminoácidos , Citocromos/química , Transporte de Elétrons , Heme/química , Modelos Moleculares , Oxirredução , Ligação Proteica , Conformação Proteica , Termodinâmica
4.
Arch Biochem Biophys ; 644: 8-16, 2018 04 15.
Artigo em Inglês | MEDLINE | ID: mdl-29486160

RESUMO

G. metallireducens bacterium has highly versatile respiratory pathways that provide the microorganism an enormous potential for many biotechnological applications. However, little is known about the structural and functional properties of its electron transfer components. In this work, the periplasmic cytochrome PpcA from G. metallireducens was studied in detail for the first time using complementary biophysical techniques, including UV-visible, CD and NMR spectroscopy. The results obtained showed that PpcA contains three low-spin c-type heme groups with His-His axial coordination, a feature also observed for its homologue in G. sulfurreducens. However, despite the high sequence homology between the two cytochromes, important structural and functional differences were observed. The comparative analysis of the backbone, side chain and heme substituents NMR signals revealed differences in the relative orientation of the hemes I and III. In addition, redox titrations followed by visible spectroscopy showed that the redox potential values for PpcA from G. metallireducens (-78 and -93 mV at pH 7 and 8, respectively) are considerably less negative. Overall, this study provides biochemical and biophysical data of a key cytochrome from G. metallireducens, paving the way to understand the extracellular electron transfer mechanisms in these bacteria.


Assuntos
Proteínas de Bactérias/química , Citocromos/química , Geobacter/enzimologia , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Dicroísmo Circular , Citocromos/genética , Citocromos/metabolismo , Geobacter/genética , Ressonância Magnética Nuclear Biomolecular , Domínios Proteicos , Espectrofotometria Ultravioleta , Homologia Estrutural de Proteína
5.
Biochim Biophys Acta Bioenerg ; 1858(9): 733-741, 2017 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-28377068

RESUMO

Gene knock-out studies on Geobacter sulfurreducens cells showed that the outer membrane-associated monoheme cytochrome OmcF is involved in respiratory pathways leading to the extracellular reduction of Fe(III) and U(VI). In addition, microarray analysis of an OmcF-deficient mutant revealed that many of the genes with decreased transcript level were those whose expression is up-regulated in cells grown with a graphite electrode as electron acceptor, suggesting that OmcF also regulates the electron transfer to electrode surfaces and the concomitant electricity production by G. sulfurreducens in microbial fuel cells. 15N,13C-labeled OmcF was produced and NMR spectroscopy was used to determine the solution structure of the protein in the fully reduced state and the pH-dependent conformational changes. In addition, 15N relaxation NMR experiments were used to characterize the overall and internal backbone dynamics of OmcF. The structure obtained is well-defined, with an average pairwise root mean square deviation of 0.37Å for the backbone atoms and 0.98Å for all heavy atoms. For the first time a solution structure and the protein motions were determined for an outer membrane cytochrome from G. sulfurreducens, which constitutes an important step to understand the extracellular electron transfer mechanism in Geobacter cells.


Assuntos
Proteínas de Bactérias/química , Geobacter/química , Heme/química , Modelos Moleculares , Movimento (Física) , Ressonância Magnética Nuclear Biomolecular , Oxirredução , Fragmentos de Peptídeos/química , Conformação Proteica , Proteínas Recombinantes/química , Soluções
6.
Phys Chem Chem Phys ; 19(13): 8908-8918, 2017 Mar 29.
Artigo em Inglês | MEDLINE | ID: mdl-28295106

RESUMO

Geobacter sulfurreducens cells have the ability to exchange electrons with conductive materials, and the periplasmic cytochrome PccH plays an essential role in the direct electrode-to-cell electron transfer in this bacterium. It has atypically low redox potential and unique structural features that differ from those observed in other c-type cytochromes. We report surface enhanced resonance Raman spectroscopic and electrochemical characterization of the immobilized PccH, together with molecular dynamics simulations that allow for the rationalization of experimental observations. Upon attachment to electrodes functionalized with partially or fully hydrophobic self-assembled monolayers, PccH displays a distribution of native and non-native heme spin configurations, similar to those observed in horse heart cytochrome c. The native structural and thermodynamic features of PccH are preserved upon attachment mixed hydrophobic (-CH3/-NH2) surfaces, while pure -OH, -NH2 and -COOH surfaces do not provide suitable platforms for its adsorption, indicating that its still unknown physiological redox partner might be membrane integrated. Neither of the employed immobilization strategies results in electrocatalytically active PccH capable of the reduction of hydrogen peroxide. Pseudoperoxidase activity is observed in immobilized microperoxidase, which is enzymatically produced from PccH and spectroscopically characterized. Further improvement of PccH microperoxidase stability is required for its application in electrochemical biosensing of hydrogen peroxide.


Assuntos
Proteínas de Bactérias/metabolismo , Citocromos c/metabolismo , Geobacter/metabolismo , Peroxidases/metabolismo , Análise Espectral Raman , Adsorção , Eletrodos , Elétrons , Termodinâmica
7.
Biochim Biophys Acta ; 1847(10): 1129-38, 2015 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-26071085

RESUMO

Humic substances (HS) constitute a significant fraction of natural organic matter in terrestrial and aquatic environments and can act as terminal electron acceptors in anaerobic microbial respiration. Geobacter sulfurreducens has a remarkable respiratory versatility and can utilize the HS analog anthraquinone-2,6-disulfonate (AQDS) as a terminal electron acceptor or its reduced form (AH2QDS) as an electron donor. Previous studies set the triheme cytochrome PpcA as a key component for HS respiration in G. sulfurreducens, but the process is far from fully understood. In this work, NMR chemical shift perturbation measurements were used to map the interaction region between PpcA and AH2QDS, and to measure their binding affinity. The results showed that the AH2QDS binds reversibly to the more solvent exposed edge of PpcA heme IV. The NMR and visible spectroscopies coupled to redox measurements were used to determine the thermodynamic parameters of the PpcA:quinol complex. The higher reduction potential of heme IV (-127mV) compared to that of AH2QDS (-184mV) explains why the electron transfer is more favorable in the case of reduction of the cytochrome by the quinol. The clear evidence obtained for the formation of an electron transfer complex between AH2QDS and PpcA, combined with the fact that the protein also formed a redox complex with AQDS, revealed for the first time the bifunctional behavior of PpcA toward an analog of the HS. Such behavior might confer selective advantage to G. sulfurreducens, which can utilize the HS in any redox state available in the environment for its metabolic needs.

8.
Biochim Biophys Acta ; 1847(10): 1113-8, 2015 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-26071083

RESUMO

The monoheme c-type cytochrome PccH from Geobacter sulfurreducens, involved in the pathway of current-consumption in biofilms, was electrochemically characterized in detail. Cyclic voltammetry was used to determine the kinetics and thermodynamics properties of PccH redox behavior. Entropy, enthalpy and Gibbs free energy changes associated with the redox center transition between the ferric and the ferrous state were determined, indicating an enhanced solvent exposure. The midpoint redox potential is considerably low for a monoheme c-type cytochrome and the heterogeneous electron transfer constant rate reflects a high efficiency of electron transfer process in PccH. The midpoint redox potential dependence on the pH (redox-Bohr effect) was investigated, over the range of 2.5 to 9.1, and is described by the protonation/deprotonation events of two distinct centers in the vicinity of the heme group with pKa values of 2.7 (pKox1); 4.1 (pKred1) and 5.9 (pKox2); 6.4 (pKred2). Based on the inspection of PccH structure, these centers were assigned to heme propionic acids P13 and P17, respectively. The observed redox-Bohr effect indicates that PccH is able to thermodynamically couple electron and proton transfer in the G. sulfurreducens physiological pH range.

9.
Biochim Biophys Acta ; 1837(6): 750-60, 2014 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-24530867

RESUMO

The bacterium Geobacter sulfurreducens displays an extraordinary respiratory versatility underpinning the diversity of electron donors and acceptors that can be used to sustain anaerobic growth. Remarkably, G. sulfurreducens can also use as electron donors the reduced forms of some acceptors, such as the humic substance analog anthraquinone-2,6-disulfonate (AQDS), a feature that confers environmentally competitive advantages to the organism. Using UV-visible and stopped-flow kinetic measurements we demonstrate that there is electron exchange between the triheme cytochrome PpcA from Gs and AQDS. 2D-(1)H-(15)N HSQC NMR spectra were recorded for (15)N-enriched PpcA samples, in the absence and presence of AQDS. Chemical shift perturbation measurements, at increasing concentration of AQDS, were used to probe the interaction region and to measure the binding affinity of the PpcA-AQDS complex. The perturbations on the NMR signals corresponding to the PpcA backbone NH and heme substituents showed that the region around heme IV interacts with AQDS through the formation of a complex with a definite life time in the NMR time scale. The comparison of the NMR data obtained for PpcA in the presence and absence of AQDS showed that the interaction is reversible. Overall, this study provides for the first time a clear illustration of the formation of an electron transfer complex between AQDS and a G. sulfurreducens triheme cytochrome, shedding light on the electron transfer pathways underlying the microbial oxidation of humics.


Assuntos
Antraquinonas/metabolismo , Citocromos/metabolismo , Geobacter/enzimologia , Substâncias Húmicas , Espectroscopia de Ressonância Magnética , Modelos Moleculares , Oxirredução , Espectrofotometria Ultravioleta
10.
Biochim Biophys Acta ; 1827(4): 484-92, 2013 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-23313804

RESUMO

Extracellular electron transfer is one of the physiological hallmarks of Geobacteraceae. Most of the Geobacter species encode for more than 100 c-type cytochromes which are, in general, poorly conserved between individual species. An exception to this is the PpcA family of periplasmic triheme c-type cytochromes, which are the most abundant proteins in these bacteria. The functional characterization of PpcA showed that it has the necessary properties to couple electron/proton transfer, a fundamental step for ATP synthesis. The detailed thermodynamic characterization of a PpcA mutant, in which the strictly conserved residue phenylalanine 15 was replaced by leucine, showed that the global redox network of cooperativities among heme groups is altered, preventing the mutant from performing a concerted electron/proton transfer. In this work, we determined the solution structure of PpcA F15L mutant in the fully reduced state using NMR spectroscopy by producing (15)N-labeled protein. In addition, pH-dependent conformational changes were mapped onto the structure. The mutant structure obtained is well defined, with an average pairwise root-mean-square deviation of 0.36Å for the backbone atoms and 1.14Å for all heavy atoms. Comparison between the mutant and wild-type structures elucidated the contribution of phenylalanine 15 in the modulation of the functional properties of PpcA.


Assuntos
Grupo dos Citocromos c/química , Geobacter/metabolismo , Heme/química , Proteínas Mutantes/química , Periplasma/metabolismo , Fenilalanina/química , Grupo dos Citocromos c/genética , Grupo dos Citocromos c/metabolismo , Geobacter/crescimento & desenvolvimento , Heme/metabolismo , Concentração de Íons de Hidrogênio , Mutagênese Sítio-Dirigida , Proteínas Mutantes/genética , Proteínas Mutantes/metabolismo , Ressonância Magnética Nuclear Biomolecular , Oxirredução , Fenilalanina/genética , Fenilalanina/metabolismo , Conformação Proteica , Termodinâmica
11.
Front Endocrinol (Lausanne) ; 15: 1359211, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38887266

RESUMO

Background: There is a lack of information on the clinical and molecular presentation of familial partial lipodystrophy (FPLD), a rare genetic disorder characterized by partial subcutaneous fat loss. Objective: This study aimed to provide a comprehensive assessment of the clinical, metabolic, and genetic features of FPLD in the Brazilian population. Methods: In a multicenter cross-sectional investigation we evaluated patients with FPLD across five Brazilian reference centers for lipodystrophies. Diagnosis of FPLD was made by clinical evaluation and genetic confirmation. Data on genetic, clinical, and metabolic characteristics were captured. Statistical analysis involved the utilization of the Kruskal-Wallis test to identify differences. Results: The study included 106 patients with genetic confirmation of FPLD. The mean age was 44 ± 15 years, and they were predominantly female (78.3%). LMNA pathogenic variants were identified in 85.8% of patients, PPARG in 10.4%, PLIN1 in 2.8%, and MFN2 in 0.9%. Diabetes mellitus (DM) was highly prevalent (57.5%), affecting 54 females (50.9%). Median triglycerides levels were 199 mg/dL (54-2724 mg/dL), severe hypertriglyceridemia (≥ 500 mg/dL) was found in 34.9% and pancreatitis in 8.5%. Metabolic-associated fatty liver disease (MAFLD) was observed in 56.6%, and cardiovascular disease in 10.4%. The overall mortality rate was 3.8%, due to cardiovascular events. Conclusion: This study presents an extensive cohort of Brazilian patients with FPLD, predominantly DM with several multisystem complications. A comprehensive characterization of lipodystrophy syndromes is crucial for effective patient management and care.


Assuntos
Lipodistrofia Parcial Familiar , Humanos , Feminino , Masculino , Lipodistrofia Parcial Familiar/genética , Lipodistrofia Parcial Familiar/epidemiologia , Adulto , Estudos Transversais , Pessoa de Meia-Idade , Brasil/epidemiologia , Morbidade , Lamina Tipo A/genética
12.
Diabetol Metab Syndr ; 16(1): 114, 2024 May 24.
Artigo em Inglês | MEDLINE | ID: mdl-38790009

RESUMO

BACKGROUND: Mesenchymal stem cell infusion and vitamin D supplementation may have immunomodulatory actions that could prolong the preservation of residual insulin secretion in patients with type 1 diabetes (T1D). Intervention with these agents after onset of T1D could favor the development of a remission phase, with potential clinical impact. We aimed to compare the presence of clinical remission (CR), glycemic control and daily insulin requirement at 6, 12, 18, 24 and 36 months after the diagnosis of T1D using IDAA1c in patients who received therapy with adipose tissue-derived mesenchymal stem cell (ASC) infusion and vitamin D supplementation and a control group. METHODS: This retrospective cohort study analyzed data from the medical records of patients with T1D diagnosed between 15 and 40 years. Partial CR was defined as an IDAA1c index < 9. Patients in the intervention group received an infusion of adipose tissued-derived mesenchymal stem cells (ASCs) within 3 months after diagnosis and supplementation with 2000 IU of cholecalciferol for 1 year, started on the day following the infusion. Partial CR was also determined using the ISPAD criteria, to assess its agreement with IDAA1c. RESULTS: A total of 28 patients were evaluated: 7 in the intervention group (group 1) and 21 in the control group (group 2). All patients in group 1 evolved with partial CR while only 46.7% of patients in group 2 had this outcome. Group 1 had a higher frequency of CR when evaluated with IDAA1c and ISPAD criteria. The mean duration of CR varied between the two criteria. Although HbA1c was similar between groups during follow-up, group 1 had a lower total daily insulin requirement (p < 0.005) at all time points. At 36 months, group 1 used 49% of the total daily insulin dose used by group 2 with similar glycemic control. CONCLUSION: The intervention with infusion of ASC + vitamin D supplementation was associated with partial CR at 6 months. Although there were no differences in CR established by the IDAA1c and ISPAD criteria after three years of follow-up, patients who underwent intervention had nearly the half insulin requirement of controls with conventional treatment, with similar glycemic control. TRIAL REGISTRATION: 37001514.0.0000.5257.

13.
Biochem Soc Trans ; 40(6): 1295-301, 2012 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-23176471

RESUMO

Extracellular electron transfer is one of the physiological hallmarks of Geobacter sulfurreducens, allowing these bacteria to reduce toxic and/or radioactive metals and grow on electrode surfaces. Aiming to functionally optimize the respiratory electron-transfer chains, such properties can be explored through genetically engineered strains. Geobacter species comprise a large number of different multihaem c-type cytochromes involved in the extracellular electron-transfer pathways. The functional characterization of multihaem proteins is particularly complex because of the coexistence of several microstates in solution, connecting the fully reduced and oxidized states. NMR spectroscopy has been used to monitor the stepwise oxidation of each individual haem and thus to obtain information on each microstate. For the structural study of these proteins, a cost-effective isotopic labelling of the protein polypeptide chains was combined with the comparative analysis of 1H-13C HSQC (heteronuclear single-quantum correlation) NMR spectra obtained for labelled and unlabelled samples. These new methodological approaches allowed us to study G. sulfurreducens haem proteins functionally and structurally, revealing functional mechanisms and key residues involved in their electron-transfer capabilities. Such advances can now be applied to the design of engineered haem proteins to improve the bioremediation and electricity-harvesting skills of G. sulfurreducens.


Assuntos
Proteínas de Bactérias/metabolismo , Citocromos/metabolismo , Proteínas de Bactérias/química , Proteínas de Bactérias/genética , Biodegradação Ambiental , Biotecnologia , Citocromos/química , Citocromos/genética , Transporte de Elétrons , Compostos Férricos/metabolismo , Geobacter/genética , Modelos Biológicos , Oxirredução , Conformação Proteica
14.
J Biol Inorg Chem ; 17(1): 11-24, 2012 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-21805398

RESUMO

Cytochromes c(7) are periplasmic triheme proteins that have been reported exclusively in δ-proteobacteria. The structures of five triheme cytochromes identified in Geobacter sulfurreducens and one in Desulfuromonas acetoxidans have been determined. In addition to the hemes and axial histidines, a single aromatic residue is conserved in all these proteins-phenylalanine 15 (F15). PpcA is a member of the G. sulfurreducens cytochrome c(7) family that performs electron/proton energy transduction in addition to electron transfer that leads to the reduction of extracellular electron acceptors. For the first time we probed the role of the F15 residue in the PpcA functional mechanism, by replacing this residue with the aliphatic leucine by site-directed mutagenesis. The analysis of NMR spectra of both oxidized and reduced forms showed that the heme core and the overall fold of the mutated protein were not affected. However, the analysis of (1)H-(15)N heteronuclear single quantum coherence NMR spectra evidenced local rearrangements in the α-helix placed between hemes I and III that lead to structural readjustments in the orientation of heme axial ligands. The detailed thermodynamic characterization of F15L mutant revealed that the reduction potentials are more negative and the redox-Bohr effect is decreased. The redox potential of heme III is most affected. It is of interest that the mutation in F15, located between hemes I and III in PpcA, changes the characteristics of the two hemes differently. Altogether, these modifications disrupt the balance of the global network of cooperativities, preventing the F15L mutant protein from performing a concerted electron/proton transfer.


Assuntos
Grupo dos Citocromos c/química , Grupo dos Citocromos c/metabolismo , Fenilalanina/metabolismo , Sequência de Aminoácidos , Grupo dos Citocromos c/genética , Desulfuromonas/química , Geobacter/química , Mutagênese Sítio-Dirigida , Ressonância Magnética Nuclear Biomolecular , Oxirredução , Alinhamento de Sequência , Termodinâmica
15.
Bioinorg Chem Appl ; 2012: 298739, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-22899897

RESUMO

The bacterium Geobacter sulfurreducens (Gs) can grow in the presence of extracellular terminal acceptors, a property that is currently explored to harvest electricity from aquatic sediments and waste organic matter into microbial fuel cells. A family composed of five triheme cytochromes (PpcA-E) was identified in Gs. These cytochromes play a crucial role by bridging the electron transfer from oxidation of cytoplasmic donors to the cell exterior and assisting the reduction of extracellular terminal acceptors. The detailed thermodynamic characterization of such proteins showed that PpcA and PpcD have an important redox-Bohr effect that might implicate these proteins in the e(-)/H(+) coupling mechanisms to sustain cellular growth. The physiological relevance of the redox-Bohr effect in these proteins was studied by determining the fractional contribution of each individual redox-microstate at different pH values. For both proteins, oxidation progresses from a particular protonated microstate to a particular deprotonated one, over specific pH ranges. The preferred e(-)/H(+) transfer pathway established by the selected microstates indicates that both proteins are functionally designed to couple e(-)/H(+) transfer at the physiological pH range for cellular growth.

16.
Arch Endocrinol Metab ; 66(4): 489-497, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35758834

RESUMO

Introduction: Binge eating disorder (BED) is the most prevalent eating disorder in individuals with obesity. Its association with factors that control hunger and satiety has not yet been elucidated. We evaluated whether levels of inflammatory markers, frequency of psychiatric comorbidities, and appetite-related hormones levels differ between individuals with obesity with and without BED. Subjects and methods: The Structured Clinical Interview for Diagnostic and Statistical Manual of Mental Disorders-5 - Clinician Version (SCID-5-CV), Binge Eating Scale, and Hospital Anxiety and Depression Scale were evaluated in 39 individuals with obesity. Plasma levels of C-reactive protein (CRP), tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), leptin, ghrelin, and glucagon-like peptide-1 (GLP-1) were measured. Results: Individuals of the BED group exhibited significantly higher percentages of altered eating patterns (hyperphagia, bingeing, post-dinner eating, feeling "stuffed", and emotional eating), higher depressive symptom scores and levels of leptin, CRP, and TNF-α, compared to those from the non-BED group. Logistic regression showed that BED was independently associated with depressive symptoms and CRP levels. Conclusion: Individuals with obesity and BED showed greater psychiatric comorbidity, worse eating patterns and worse inflammatory profile than those without BED. BED should be assessed as an indicator of clinical severity in patients with obesity.


Assuntos
Transtorno da Compulsão Alimentar , Transtorno da Compulsão Alimentar/complicações , Transtorno da Compulsão Alimentar/diagnóstico , Transtorno da Compulsão Alimentar/psicologia , Estudos Transversais , Depressão , Humanos , Leptina , Obesidade/complicações , Fator de Necrose Tumoral alfa
17.
Arch Endocrinol Metab ; 65(4): 436-442, 2021 Nov 03.
Artigo em Inglês | MEDLINE | ID: mdl-34283897

RESUMO

OBJECTIVE: The aim of the study was to assess the autoimmunity in first degrees relatives (FDR) of patients with type 1 diabetes (T1DM) and the progression to T1DM after 10 years of follow up in the Brazilian population. METHODS: Non-diabetic FDR of T1DM patients were interviewed and blood was drawn for autoantibodies measurement (GADA, IA-2A, IAA, ZnT8A). Serum samples were analyzed by standard radioligand binding assays performed at the Federal University of Rio de Janeiro (GADA, IAA and IA2A), and at the Skäne University Hospital, Sweden (ZnT8A). The FDR were interviewed by phone after 10 years to determine if they had developed T1DM. Descriptive statistical analysis was performed and results were described as means and standard deviation (SD). RESULTS: 81 individuals were analyzed. Thirteen subjects had positive autoantibodies associated with T1DM.10 were positive for 1 autoantibody and 3 subjects were positive for multiple autoantibodies (1 of them showed positivity for 2 autoantibodies - GADA, ZnT8A - and the other two were positive for 3 autoantibodies - GADA, IA2A, ZnT8A). The 3 subjects with multiple positive autoantibodies developed T1DM within 10 years. CONCLUSION: In Brazilian FDR of T1DM patients, the positivity for multiple autoantibodies indicate a greater chance of progression to T1DM, similar to observed in Caucasians. ZnT8A was helpful in the risk assessment for T1DM development.


Assuntos
Diabetes Mellitus Tipo 1 , Autoanticorpos , Biomarcadores , Diabetes Mellitus Tipo 1/genética , Seguimentos , Glutamato Descarboxilase , Humanos , Estudos Retrospectivos
18.
Cardiovasc Intervent Radiol ; 44(4): 598-606, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33527186

RESUMO

INTRODUCTION: To evaluate the efficacy and clinical safety of bariatric arterial embolization (BAE) in adults with body mass index (BMI) between 30 and 39.9 kg/m2 and metabolic syndrome (MS). MATERIALS AND METHODS: Between March and August 2018, ten female participants between 21 and 48-years-old, median BMI of 36.37 ± 2.58 kg/m2 and MS were enrolled in this prospective trial. We embolized the fundal branches from the left gastric and other artery sources, which resulted in embolization of at least two arteries in 9 out 10 participants. Six months after bariatric embolization, efficacy was assessed by changes in total body weight (TBW), ghrelin and Homeostatic Model Assessment-Insulin Resistance (HOMA-IR) levels and by changes in quality of life (QOL) and in binge eating scale (BES) scores. Safety was assessed by the identification of any related complications, including gastric ulcers, screened by gastrointestinal endoscopy, performed before and one week and one month after BAE. RESULTS: Six months after embolization, TBW decreased by 6.8% (6.22 kg ± 3.6;p = .01), serum ghrelin dropped from 25.39 pg/ml ± 10.63 to 17.1 ± 8.07 (p = 0.01), and HOMA-IR decreased from 7.29 ± 5.66 to 3.73 ± 1.99 (p = 0.01). The QOL scores improved from 59.64 ± 5.59 to 69.02 ± 11.97 (p < 0.05) and in the BES from 21.50 ± 8.89 to 9.60 ± 4.40 (p = 0.01). Endoscopy revealed symptomatic gastric ulcers in two participants, which had healed without sequelae. In one participant, ultrasound revealed an asymptomatic focal arterial thrombus at the left distal radial artery puncture site. CONCLUSION: BAE is effective in reducing weight, insulin resistance and ghrelin levels and improving BES and QOL scores in patients with class I and II obesity and MS, with no major complications.


Assuntos
Índice de Massa Corporal , Embolização Terapêutica/métodos , Síndrome Metabólica/terapia , Obesidade/terapia , Redução de Peso/fisiologia , Adolescente , Adulto , Endoscopia Gastrointestinal , Feminino , Humanos , Masculino , Síndrome Metabólica/complicações , Síndrome Metabólica/diagnóstico , Pessoa de Meia-Idade , Obesidade/complicações , Obesidade/fisiopatologia , Projetos Piloto , Estudos Prospectivos , Qualidade de Vida , Adulto Jovem
19.
Arch Endocrinol Metab ; 65(3): 342-351, 2021 Nov 03.
Artigo em Inglês | MEDLINE | ID: mdl-33939911

RESUMO

OBJECTIVE: Adipose tissue-derived stromal/stem cells (ASCs) and vitamin D have immunomodulatory actions that could be useful for type 1 diabetes (T1D). We aimed in this study to investigate the safety and efficacy of ASCs + daily cholecalciferol (VIT D) for 6 months in patients with recent-onset T1D. METHODS: In this prospective, dual-center, open trial, patients with recent onset T1D received one dose of allogenic ASC (1 × 106 cells/kg) and cholecalciferol 2,000 UI/day for 6 months (group 1). They were compared to patients who received chol-ecalciferol (group 2) and standard treatment (group 3). Adverse events were recorded; C-peptide (CP), insulin dose and HbA1c were measured at baseline (T0), after 3 (T3) and 6 months (T6). RESULTS: In group 1 (n = 7), adverse events included transient headache (all), mild local reactions (all), tachycardia (n = 4), abdominal cramps (n = 1), thrombophlebitis (n = 4), scotomas (n = 2), and central retinal vein occlusion at T3 (n = 1, resolution at T6). Group 1 had an increase in basal CP (p = 0.018; mean: 40.41+/-40.79 %), without changes in stimulated CP after mixed meal (p = 0.62), from T0 to T6. Basal CP remained stable in groups 2 and 3 (p = 0.58 and p = 0.116, respectively). Group 1 had small insulin requirements (0.31+/- 0.26 UI/kg) without changes at T6 (p = 0.44) and HbA1c decline (p = 0.01). At T6, all patients (100%; n = 7) in group 1 were in honeymoon vs 75% (n = 3/4) and 50% (n = 3/6) in groups 2 and 3, p = 0.01. CONCLUSION: Allogenic ASC + VIT D without immunosuppression was safe and might have a role in the preservation of ß-cells in patients with recent-onset T1D. ClinicalTrials.gov: NCT03920397.


Assuntos
Colecalciferol/uso terapêutico , Diabetes Mellitus Tipo 1 , Transplante de Células-Tronco Mesenquimais , Células-Tronco/citologia , Tecido Adiposo/citologia , Diabetes Mellitus Tipo 1/tratamento farmacológico , Humanos , Projetos Piloto , Estudos Prospectivos
20.
Biomol NMR Assign ; 14(1): 31-36, 2020 04.
Artigo em Inglês | MEDLINE | ID: mdl-31617060

RESUMO

The bacterium Geobacter metallireducens is capable of transferring electrons to the cell exterior, a process designated extracellular electron transfer. This mechanism allows the microorganism to reduce extracellular acceptors such as Fe(III) (hydr)oxides and water toxic and/or radioactive contaminants including Cr(VI) and U(VI). It is also capable of oxidizing waste water aromatic organic compounds being an important microorganism for bioremediation of polluted waters. Extracellular electron transfer also allows electricity harvesting from microbial fuel cells, a promising sustainable form of energy production. However, extracellular electron transfer processes in this microorganism are still poorly characterized. The triheme c-type cytochrome PpcA from G. metallireducens is abundant in the periplasm and is crucial for electron transfer between the cytoplasm and the cell's exterior. In this work, we report near complete assignment of backbone, side chain and heme resonances for PpcA in the oxidized state that will permit its structure determination and identification of interactions with physiological redox partners.


Assuntos
Proteínas de Bactérias/química , Citocromos/química , Geobacter/metabolismo , Heme/química , Ressonância Magnética Nuclear Biomolecular , Isótopos de Nitrogênio , Oxirredução , Estrutura Secundária de Proteína , Espectroscopia de Prótons por Ressonância Magnética
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