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1.
Int J Biol Macromol ; 262(Pt 1): 129781, 2024 Mar.
Article in English | MEDLINE | ID: mdl-38296131

ABSTRACT

Thioredoxins (TRXs) are ubiquitous small, globular proteins involved in cell redox processes. In this work, we report the solution structure of TRX m from Pisum sativum (pea), which has been determined on the basis of 1444 nuclear Overhauser effect- (NOE-) derived distance constraints. The average pairwise root-mean-square deviation (RMSD) for the 20 best structures for the backbone residues (Val7-Glu102) was 1.42 ± 0.15 Å, and 1.97 ± 0.15 Å when all heavy atoms were considered. The structure corresponds to the typical fold of TRXs, with a central five-stranded ß-sheet flanked by four α-helices. Some residues had an important exchange dynamic contribution: those around the active site; at the C terminus of ß-strand 3; and in the loop preceding α-helix 4. Smaller NOE values were observed at the N and C-terminal residues forming the elements of the secondary structure or, alternatively, in the residues belonging to the loops between those elements. A peptide derived from pea fructose-1,6-biphosphatase (FBPase), comprising the preceding region to the regulatory sequence of FBPase (residues Glu152 to Gln179), was bound to TRX m with an affinity in the low micromolar range, as measured by fluorescence and NMR titration experiments. Upon peptide addition, the intensities of the cross-peaks of all the residues of TRX m were affected, as shown by NMR. The value of the dissociation constant of the peptide from TRX m was larger than that of the intact FBPase, indicating that there are additional factors in other regions of the polypeptide chain of the latter protein affecting the binding to thioredoxin.


Subject(s)
Chloroplast Thioredoxins , Pisum sativum , Chloroplast Thioredoxins/metabolism , Amino Acid Sequence , Magnetic Resonance Spectroscopy , Peptides
2.
Anal Chem ; 95(45): 16539-16548, 2023 11 14.
Article in English | MEDLINE | ID: mdl-37906730

ABSTRACT

Studying metabolism may assist in understanding the relationship between normal and dysfunctional mitochondrial activity and various diseases, such as neurodegenerative, cardiovascular, autoimmune, psychiatric, and cancer. Nuclear magnetic resonance-based metabolomics represents a powerful method to characterize the chemical content of complex samples and has been successfully applied to studying a range of conditions. However, an optimized methodology is lacking for analyzing isolated organelles, such as mitochondria. In this study, we report the development of a protocol to metabolically profile mitochondria from healthy, tumoral, and metastatic tissues. Encouragingly, this approach provided quantitative information about up to 45 metabolites in one comprehensive and robust analysis. Our results revealed significant differences between whole-cell and mitochondrial metabolites, which supports a more refined approach to metabolic analysis. We applied our optimized methodology to investigate aggressive and metastatic breast cancer in mouse tissues, discovering that lung mitochondria exhibit an altered metabolic fingerprint. Specific amino acids, organic acids, and lipids showed significant increases in levels when compared with mitochondria from healthy tissues. Our optimized methodology could promote a better understanding of the molecular mechanisms underlying breast cancer aggressiveness and mitochondrial-related diseases and support the optimization of new advanced therapies.


Subject(s)
Mitochondria , Neoplasms , Mice , Animals , Mitochondria/metabolism , Metabolomics/methods , Neoplasms/metabolism , Magnetic Resonance Spectroscopy , Amino Acids/metabolism
3.
Front Mol Biosci ; 10: 1204273, 2023.
Article in English | MEDLINE | ID: mdl-37457832

ABSTRACT

How the human body reacts to the exposure of HIV-1 is an important research goal. Frequently, HIV exposure leads to infection, but some individuals show natural resistance to this infection; they are known as HIV-1-exposed but seronegative (HESN). Others, although infected but without antiretroviral therapy, control HIV-1 replication and progression to AIDS; they are named controllers, maintaining low viral levels and an adequate count of CD4+ T lymphocytes. Biological mechanisms explaining these phenomena are not precise. In this context, metabolomics emerges as a method to find metabolites in response to pathophysiological stimuli, which can help to establish mechanisms of natural resistance to HIV-1 infection and its progression. We conducted a cross-sectional study including 30 HESN, 14 HIV-1 progressors, 14 controllers and 30 healthy controls. Plasma samples (directly and deproteinized) were analyzed through Nuclear Magnetic Resonance (NMR) metabolomics to find biomarkers and altered metabolic pathways. The metabolic profile analysis of progressors, controllers and HESN demonstrated significant differences with healthy controls when a discriminant analysis (PLS-DA) was applied. In the discriminant models, 13 metabolites associated with HESN, 14 with progressors and 12 with controllers were identified, which presented statistically significant mean differences with healthy controls. In progressors, the metabolites were related to high energy expenditure (creatinine), mood disorders (tyrosine) and immune activation (lipoproteins), phenomena typical of the natural course of the infection. In controllers, they were related to an inflammation-modulating profile (glutamate and pyruvate) and a better adaptive immune system response (acetate) associated with resistance to progression. In the HESN group, with anti-inflammatory (lactate and phosphocholine) and virucidal (lactate) effects which constitute a protective profile in the sexual transmission of HIV. Concerning the significant metabolites of each group, we identified 24 genes involved in HIV-1 replication or virus proteins that were all altered in progressors but only partially in controllers and HESN. In summary, our results indicate that exposure to HIV-1 in HESN, as well as infection in progressors and controllers, affects the metabolism of individuals and that this affectation can be determined using NMR metabolomics.

4.
Toxins (Basel) ; 15(6)2023 05 24.
Article in English | MEDLINE | ID: mdl-37368656

ABSTRACT

Mycotoxins are secondary metabolites produced by certain filamentous fungi. They are common contaminants found in a wide variety of food matrices, thus representing a threat to public health, as they can be carcinogenic, mutagenic, or teratogenic, among other toxic effects. Several hundreds of mycotoxins have been reported, but only a few of them are regulated, due to the lack of data regarding their toxicity and mechanisms of action. Thus, a more comprehensive evaluation of the toxicity of mycotoxins found in foodstuffs is required. In silico toxicology approaches, such as Quantitative Structure-Activity Relationship (QSAR) models, can be used to rapidly assess chemical hazards by predicting different toxicological endpoints. In this work, for the first time, a comprehensive database containing 4360 mycotoxins classified in 170 categories was constructed. Then, specific robust QSAR models for the prediction of mutagenicity, genotoxicity, and carcinogenicity were generated, showing good accuracy, precision, sensitivity, and specificity. It must be highlighted that the developed QSAR models are compliant with the OECD regulatory criteria, and they can be used for regulatory purposes. Finally, all data were integrated into a web server that allows the exploration of the mycotoxin database and toxicity prediction. In conclusion, the developed tool is a valuable resource for scientists, industry, and regulatory agencies to screen the mutagenicity, genotoxicity, and carcinogenicity of non-regulated mycotoxins.


Subject(s)
Mutagens , Mycotoxins , Mutagens/toxicity , Mutagenicity Tests , Mycotoxins/toxicity , Mutagenesis , Carcinogens/toxicity
5.
Arch Biochem Biophys ; 736: 109538, 2023 03 01.
Article in English | MEDLINE | ID: mdl-36738980

ABSTRACT

The phosphotransferase system (PTS), a metabolic pathway formed by five proteins, modulates the use of sugars in bacteria. The second protein in the chain is the histidine phosphocarrier, HPr, with the binding site at His15. The HPr kinase/phosphorylase (HPrK/P), involved in the bacterial use of carbon sources, phosphorylates HPr at Ser46, and it binds at its binding site. The regulator of sigma D protein (Rsd) also binds to HPr at His15. We have designed fragments of HPr, growing from its N-terminus and containing the His15. In this work, we obtained three fragments, HPr38, HPr58 and HPr70, comprising the first thirty-eight, fifty-eight and seventy residues of HPr, respectively. All fragments were mainly disordered, with evidence of a weak native-like, helical population around the binding site, as shown by fluorescence, far-ultraviolet circular dichroism, size exclusion chromatography and nuclear magnetic resonance. Although HPr38, HPr58 and HPr70 were disordered, they could bind to: (i) the N-terminal domain of first protein of the PTS, EIN; (ii) Rsd; and, (iii) HPrK/P, as shown by fluorescence and biolayer interferometry (BLI). The association constants for each protein to any of the fragments were in the low micromolar range, within the same range than those measured in the binding of HPr to each protein. Then, although acquisition of stable, native-like secondary and tertiary structures occurred at the last residues of the polypeptide, the ability to bind protein partners happened much earlier in the growing chain. Binding was related to the presence of the native-like structure around His15.


Subject(s)
Bacterial Proteins , Histidine , Histidine/chemistry , Bacterial Proteins/chemistry , Peptides/metabolism , Binding Sites , Magnetic Resonance Spectroscopy , Phosphorylation
6.
J Clin Med ; 12(2)2023 Jan 10.
Article in English | MEDLINE | ID: mdl-36675484

ABSTRACT

The prevalence of diabetes type 1 (T1D) in the world populations is continuously growing. Although treatment methods are improving, the diagnostic is still symptom-based and sometimes far after onset of the disease. In this context, the aim of the study was the search of new biomarkers of the disease in red blood cells (RBCs), until now unexplored. The metabolomic and the lipidomic profile of RBCs from T1D patients and matched healthy controls was determined by NMR spectroscopy, and different multivariate discrimination models were built to select the metabolites and lipids that change most significantly. Relevant metabolites were further confirmed by univariate statistical analysis. Robust separation in the metabolomic and lipidomic profiles of RBCs from patients and controls was confirmed by orthogonal projection on latent structure discriminant analysis (OPLS-DA), random forest analysis, and significance analysis of metabolites (SAM). The main changes were detected in the levels of amino acids, organic acids, creatine and phosphocreatine, lipid change length, and choline derivatives, demonstrating changes in glycolysis, BCAA metabolism, and phospholipid metabolism. Our study proves that robust differences exist in the metabolic and lipidomic profile of RBCs from T1D patients, in comparison with matched healthy individuals. Some changes were similar to alterations found already in RBCs of T2D patients, but others seemed to be specific for type 1 diabetes. Thus, many of the metabolic differences found could be biomarker candidates for an earlier diagnosis or monitoring of patients with T1D.

7.
Front Cell Dev Biol ; 11: 1305835, 2023.
Article in English | MEDLINE | ID: mdl-38250328

ABSTRACT

Polyphenolic compounds constitute a diverse group of natural components commonly occurring in various plant species, known for their potential to exert both beneficial and detrimental effects. Additionally, these polyphenols have also been implicated as endocrine-disrupting (ED) chemicals, raising concerns about their widespread use in the cosmetics industry. In this comprehensive review, we focus on the body of literature pertaining to the estrogenic properties of ED chemicals, with a particular emphasis on the interaction of isoflavones with estrogen receptors. Within this review, we aim to elucidate the multifaceted roles and effects of polyphenols on the skin, exploring their potential benefits as well as their capacity to act as ED agents. By delving into this intricate subject matter, we intend to provoke thoughtful consideration, effectively opening a Pandora's box of questions for the reader to ponder. Ultimately, we invite the reader to contemplate whether polyphenols should be regarded as friends or foes in the realm of skincare and endocrine disruption.

8.
STAR Protoc ; 3(1): 101195, 2022 03 18.
Article in English | MEDLINE | ID: mdl-35252884

ABSTRACT

Somatic energy reserves are essential for reproductive success and can govern the onset of sexual maturation. Here, we present a toolkit to analyze the metabolic status of Drosophila larvae using an optimized NMR profiling assay in dissected tissues or whole animals, as well as a complementary protocol for the dissection and staining of key organs in nutrient sensing. This toolkit will aid investigations into critical body weight signaling and how it is sensed for maturation commitment in Drosophila. For complete details on the use and execution of this profile, please refer to Juarez-Carreño et al. (2021).


Subject(s)
Drosophila melanogaster , Drosophila , Animals , Drosophila melanogaster/metabolism , Larva/metabolism , Magnetic Resonance Spectroscopy , Staining and Labeling
9.
Cells ; 11(3)2022 01 20.
Article in English | MEDLINE | ID: mdl-35159141

ABSTRACT

Parkinson's disease (PD) is the second-most common neurodegenerative disorder, whose physiopathology is still unclear. Moreover, there is an urgent need to discover new biomarkers and therapeutic targets to facilitate its diagnosis and treatment. Previous studies performed in PD models and samples from PD patients already demonstrated that metabolic alterations are associated with this disease. In this context, the aim of this study is to provide a better understanding of metabolic disturbances underlying PD pathogenesis. To achieve this goal, we used a Drosophila PD model based on inactivation of the DJ-1ß gene (ortholog of human DJ-1). Metabolomic analyses were performed in 1-day-old and 15-day-old DJ-1ß mutants and control flies using 1H nuclear magnetic resonance spectroscopy, combined with expression and enzymatic activity assays of proteins implicated in altered pathways. Our results showed that the PD model flies exhibited protein metabolism alterations, a shift fromthe tricarboxylic acid cycle to glycolytic pathway to obtain ATP, together with an increase in the expression of some urea cycle enzymes. Thus, these metabolic changes could contribute to PD pathogenesis and might constitute possible therapeutic targets and/or biomarkers for this disease.


Subject(s)
Drosophila Proteins , Parkinson Disease , Protein Deglycase DJ-1 , Animals , Disease Models, Animal , Drosophila/metabolism , Drosophila Proteins/genetics , Drosophila Proteins/metabolism , Humans , Nerve Tissue Proteins/metabolism , Oxidative Stress/physiology , Parkinson Disease/metabolism , Protein Deglycase DJ-1/genetics , Protein Deglycase DJ-1/metabolism
10.
Int J Mol Sci ; 22(22)2021 Nov 09.
Article in English | MEDLINE | ID: mdl-34830014

ABSTRACT

In a global aging population, it is important to understand the factors affecting systemic aging and lifespan. Mitohormesis, an adaptive response caused by different insults affecting the mitochondrial network, triggers a response from the nuclear genome inducing several pathways that promote longevity and metabolic health. Understanding the role of mitochondrial function during the aging process could help biomarker identification and the development of novel strategies for healthy aging. Herein, we interfered the muscle expression of the Drosophila genes Marf and Opa1, two genes that encode for proteins promoting mitochondrial fusion, orthologues of human MFN2 and OPA1. Silencing of Marf and Opa1 in muscle increases lifespan, improves locomotor capacities in the long term, and maintains muscular integrity. A metabolomic analysis revealed that muscle down-regulation of Marf and Opa1 promotes a non-autonomous systemic metabolome reorganization, mainly affecting metabolites involved in the energetic homeostasis: carbohydrates, lipids and aminoacids. Interestingly, the differences are consistently more evident in younger flies, implying that there may exist an anticipative adaptation mediating the protective changes at the older age. We demonstrate that mild mitochondrial muscle disturbance plays an important role in Drosophila fitness and reveals metabolic connections between tissues. This study opens new avenues to explore the link of mitochondrial dynamics and inter-organ communication, as well as their relationship with muscle-related pathologies, or in which muscle aging is a risk factor for their appearance. Our results suggest that early intervention in muscle may prevent sarcopenia and promote healthy aging.


Subject(s)
Aging/genetics , Longevity/genetics , Metabolome/genetics , Mitochondria, Muscle/genetics , Aging/pathology , Animals , Animals, Genetically Modified/genetics , Animals, Genetically Modified/growth & development , Drosophila Proteins/genetics , Drosophila melanogaster/genetics , Gene Expression Regulation, Developmental/genetics , Mitochondria, Muscle/metabolism , Mitochondrial Dynamics/genetics
11.
Life (Basel) ; 11(11)2021 Nov 18.
Article in English | MEDLINE | ID: mdl-34833136

ABSTRACT

Dravet syndrome is a severe rare epileptic disease caused by mutations in the SCN1A gene coding for the Nav1.1 protein, a voltage-gated sodium channel alpha subunit. We have made a knock-out of the paralytic gene, the single Drosophila melanogaster gene encoding this type of protein, by homologous recombination. These flies showed a heat-induced seizing phenotype, and sudden death in long term seizures. In addition to seizures, neuromuscular alterations were observed in climbing, flight, and walking tests. Moreover, they also manifested some cognitive alterations, such as anxiety and problems in learning. Electrophysiological analyses from larval motor neurons showed a decrease in cell capacitance and membrane excitability, while persistent sodium current increased. To detect alterations in metabolism, we performed an NMR metabolomic profiling of heads, which revealed higher levels in some amino acids, succinate, and lactate; and also an increase in the abundance of GABA, which is the main neurotransmitter implicated in Dravet syndrome. All these changes in the paralytic knock-out flies indicate that this is a good model for epilepsy and specifically for Dravet syndrome. This model could be a new tool to understand the pathophysiology of the disease and to find biomarkers, genetic modifiers and new treatments.

12.
Cell Rep ; 37(2): 109830, 2021 10 12.
Article in English | MEDLINE | ID: mdl-34644570

ABSTRACT

Fat stores are critical for reproductive success and may govern maturation initiation. Here, we report that signaling and sensing fat sufficiency for sexual maturation commitment requires the lipid carrier apolipophorin in fat cells and Sema1a in the neuroendocrine prothoracic gland (PG). Larvae lacking apolpp or Sema1a fail to initiate maturation despite accruing sufficient fat stores, and they continue gaining weight until death. Mechanistically, sensing peripheral body-fat levels via the apolipophorin/Sema1a axis regulates endocytosis, endoplasmic reticulum remodeling, and ribosomal maturation for the acquisition of the PG cells' high biosynthetic and secretory capacity. Downstream of apolipophorin/Sema1a, leptin-like upd2 triggers the cessation of feeding and initiates sexual maturation. Human Leptin in the insect PG substitutes for upd2, preventing obesity and triggering maturation downstream of Sema1a. These data show how peripheral fat levels regulate the control of the maturation decision-making process via remodeling of endomembranes and ribosomal biogenesis in gland cells.


Subject(s)
Adipose Tissue/metabolism , Adiposity , Drosophila melanogaster/metabolism , Endocrine Glands/metabolism , Ribosomes/metabolism , Sexual Maturation , Adipose Tissue/embryology , Animals , Animals, Genetically Modified , Drosophila Proteins/genetics , Drosophila Proteins/metabolism , Drosophila melanogaster/embryology , Drosophila melanogaster/genetics , Endocrine Glands/embryology , Fatty Acid-Binding Proteins/genetics , Fatty Acid-Binding Proteins/metabolism , Gene Expression Regulation, Developmental , Glycoproteins/genetics , Glycoproteins/metabolism , Larva/genetics , Larva/metabolism , Lipogenesis , Protein Transport , Ribosomes/genetics , Semaphorins/genetics , Semaphorins/metabolism , Signal Transduction
13.
Int J Mol Sci ; 22(19)2021 Oct 06.
Article in English | MEDLINE | ID: mdl-34639146

ABSTRACT

The phosphoenolpyruvate-dependent phosphotransferase system (PTS) modulates the preferential use of sugars in bacteria. The first proteins in the cascade are common to all organisms (EI and HPr). The active site of HPr involves a histidine (His15) located immediately before the beginning of the first α-helix. The regulator of sigma D (Rsd) protein also binds to HPr. The region of HPr comprising residues Gly9-Ala30 (HPr9-30), involving the first α-helix (Ala16-Thr27) and the preceding active site loop, binds to both the N-terminal region of EI and intact Rsd. HPr9-30 is mainly disordered. We attempted to improve the affinity of HPr9-30 to both proteins by mutating its sequence to increase its helicity. We designed peptides that led to a marginally larger population in solution of the helical structure of HPr9-30. Molecular simulations also suggested a modest increment in the helical population of mutants, when compared to the wild-type. The mutants, however, were bound with a less favorable affinity than the wild-type to both the N-terminal of EI (EIN) or Rsd, as tested by isothermal titration calorimetry and fluorescence. Furthermore, mutants showed lower antibacterial properties against Staphylococcus aureus than the wild-type peptide. Therefore, we concluded that in HPr, a compromise between binding to its partners and residual structure at the active site must exist to carry out its function.


Subject(s)
Anti-Bacterial Agents/pharmacology , Bacterial Proteins/metabolism , Histidine/metabolism , Mutation , Peptide Fragments/pharmacology , Phosphoenolpyruvate Sugar Phosphotransferase System/metabolism , Staphylococcus aureus/drug effects , Anti-Bacterial Agents/chemistry , Bacterial Proteins/chemistry , Bacterial Proteins/genetics , Binding Sites , Catalytic Domain , Histidine/chemistry , Peptide Fragments/chemistry , Phosphoenolpyruvate Sugar Phosphotransferase System/chemistry , Phosphoenolpyruvate Sugar Phosphotransferase System/genetics , Staphylococcus aureus/metabolism
14.
Biochim Biophys Acta Gen Subj ; 1865(12): 130015, 2021 12.
Article in English | MEDLINE | ID: mdl-34537288

ABSTRACT

BACKGROUND: The phosphotransferase system (PTS) modulates the preferential use of sugars in bacteria. It is formed by a protein cascade in which the first two proteins are general (namely enzyme I, EI, and the histidine phosphocarrier protein, HPr) and the others are sugar-specific permeases; the active site of HPr is His15. The HPr kinase/phosphorylase (HPrK/P), involved in the use of carbon sources in Gram-positive, phopshorylates HPr at a serine. The regulator of sigma D protein (Rsd) also binds to HPr. We are designing specific fragments of HPr, which can be used to interfere with those protein-protein interactions (PPIs), where the intact HPr intervenes. METHODS: We obtained a fragment (HPr48) comprising the first forty-eight residues of HPr. HPr48 was disordered as shown by fluorescence, far-ultraviolet (UV) circular dichroism (CD), small angle X-ray scattering (SAXS) and nuclear magnetic resonance (NMR). RESULTS: Secondary structure propensities, from the assigned backbone nuclei, further support the unfolded nature of the fragment. However, HPr48 was capable of binding to: (i) the N-terminal region of EI, EIN; (ii) the intact Rsd; and, (iii) HPrK/P, as shown by fluorescence, far-UV CD, NMR and biolayer interferometry (BLI). The association constants for each protein, as measured by fluorescence and BLI, were in the order of the low micromolar range, similar to those measured between the intact HPr and each of the other macromolecules. CONCLUSIONS: Although HPr48 is forty-eight-residue long, it assisted antibiotics to exert antimicrobial activity. GENERAL SIGNIFICANCE: HPr48 could be used as a lead compound in the development of new antibiotics, or, alternatively, to improve the efficiency of existing ones.


Subject(s)
Bacterial Proteins , Histidine , Protein Serine-Threonine Kinases , Scattering, Small Angle
15.
Front Mol Biosci ; 8: 684622, 2021.
Article in English | MEDLINE | ID: mdl-34291085

ABSTRACT

The intracellular environment is crowded with macromolecules, including sugars, proteins and nucleic acids. In the cytoplasm, crowding effects are capable of excluding up to 40% of the volume available to any macromolecule when compared to dilute conditions. NUPR1 is an intrinsically disordered protein (IDP) involved in cell-cycle regulation, stress-cell response, apoptosis processes, DNA binding and repair, chromatin remodeling and transcription. Simulations of molecular crowding predict that IDPs can adopt compact states, as well as more extended conformations under crowding conditions. In this work, we analyzed the conformation and dynamics of NUPR1 in the presence of two synthetic polymers, Ficoll-70 and Dextran-40, which mimic crowding effects in the cells, at two different concentrations (50 and 150 mg/ml). The study was carried out by using a multi-spectroscopic approach, including: site-directed spin labelling electron paramagnetic resonance spectroscopy (SDSL-EPR), nuclear magnetic resonance spectroscopy (NMR), circular dichroism (CD), small angle X-ray scattering (SAXS) and dynamic light scattering (DLS). SDSL-EPR spectra of two spin-labelled mutants indicate that there was binding with the crowders and that the local dynamics of the C and N termini of NUPR1 were partially affected by the crowders. However, the overall disordered nature of NUPR1 did not change substantially in the presence of the crowders, as shown by circular dichroism CD and NMR, and further confirmed by EPR. The changes in the dynamics of the paramagnetic probes appear to be related to preferred local conformations and thus crowding agents partially affect some specific regions, further pinpointing that NUPR1 flexibility has a key physiological role in its activity.

17.
J Biol Chem ; 296: 100228, 2021.
Article in English | MEDLINE | ID: mdl-33814345

ABSTRACT

The conserved C-terminal end segment of troponin I (TnI) plays a critical role in regulating muscle relaxation. This function is retained in the isolated C-terminal 27 amino acid peptide (residues 184-210) of human cardiac TnI (HcTnI-C27): When added to skinned muscle fibers, HcTnI-C27 reduces the Ca2+-sensitivity of activated myofibrils and facilitates relaxation without decreasing the maximum force production. However, the underlying mechanism of HcTnI-C27 function is unknown. We studied the conformational preferences of HcTnI-C27 and a myopathic mutant, Arg192His, (HcTnI-C27-H). Both peptides were mainly disordered in aqueous solution with a nascent helix involving residues from Trp191 to Ile195, as shown by NMR analysis and molecular dynamics simulations. The population of nascent helix was smaller in HcTnI-C27-H than in HcTnI-C27, as shown by circular dichroism (CD) titrations. Fluorescence and isothermal titration calorimetry (ITC) showed that both peptides bound tropomyosin (αTm), with a detectably higher affinity (∼10 µM) of HcTnI-C27 than that of HcTnI-C27-H (∼15 µM), consistent with an impaired Ca2+-desensitization effect of the mutant peptide on skinned muscle strips. Upon binding to αTm, HcTnI-C27 acquired a weakly stable helix-like conformation involving residues near Trp191, as shown by transferred nuclear Overhauser effect spectroscopy and hydrogen/deuterium exchange experiments. With the potent Ca2+-desensitization effect of HcTnI-C27 on skinned cardiac muscle from a mouse model of hypertrophic cardiomyopathy, the data support that the C-terminal end domain of TnI can function as an isolated peptide with the intrinsic capacity of binding tropomyosin, providing a promising therapeutic approach to selectively improve diastolic function of the heart.


Subject(s)
Cardiomyopathy, Hypertrophic/genetics , Muscle Fibers, Skeletal/metabolism , Myofibrils/metabolism , Peptides/chemistry , Tropomyosin/metabolism , Troponin I/chemistry , Amino Acid Sequence , Amino Acid Substitution , Animals , Binding Sites , Calcium/metabolism , Cardiomyopathy, Hypertrophic/metabolism , Cardiomyopathy, Hypertrophic/pathology , Cardiomyopathy, Hypertrophic/prevention & control , Disease Models, Animal , Gene Expression , Humans , Kinetics , Mice , Molecular Docking Simulation , Muscle Fibers, Skeletal/drug effects , Muscle Fibers, Skeletal/pathology , Muscle Relaxation , Mutation , Myofibrils/drug effects , Myofibrils/pathology , Peptides/genetics , Peptides/metabolism , Peptides/pharmacology , Protein Binding , Protein Conformation, alpha-Helical , Protein Interaction Domains and Motifs , Sequence Alignment , Sequence Homology, Amino Acid , Substrate Specificity , Tropomyosin/chemistry , Tropomyosin/genetics , Troponin I/genetics , Troponin I/metabolism
18.
PLoS One ; 16(2): e0247668, 2021.
Article in English | MEDLINE | ID: mdl-33630921

ABSTRACT

Human peripheral blood mononuclear cells (PBMCs) are part of the innate and adaptive immune system, and form a critical interface between both systems. Studying the metabolic profile of PBMC could provide valuable information about the response to pathogens, toxins or cancer, the detection of drug toxicity, in drug discovery and cell replacement therapy. The primary purpose of this study was to develop an improved processing method for PBMCs metabolomic profiling with nuclear magnetic resonance (NMR) spectroscopy. To this end, an experimental design was applied to develop an alternative method to process PBMCs at low concentrations. The design included the isolation of PBMCs from the whole blood of four different volunteers, of whom 27 cell samples were processed by two different techniques for quenching and extraction of metabolites: a traditional one using organic solvents and an alternative one employing a high-intensity ultrasound probe, the latter with a variation that includes the use of deproteinizing filters. Finally, all the samples were characterized by 1H-NMR and the metabolomic profiles were compared by the method. As a result, two new methods for PBMCs processing, called Ultrasound Method (UM) and Ultrasound and Ultrafiltration Method (UUM), are described and compared to the Folch Method (FM), which is the standard protocol for extracting metabolites from cell samples. We found that UM and UUM were superior to FM in terms of sensitivity, processing time, spectrum quality, amount of identifiable, quantifiable metabolites and reproducibility.


Subject(s)
Leukocytes, Mononuclear/metabolism , Magnetic Resonance Spectroscopy , Metabolomics , Specimen Handling/methods , Adult , Humans , Leukocytes, Mononuclear/cytology , Male , Middle Aged
19.
Aging (Albany NY) ; 13(4): 4850-4880, 2021 02 19.
Article in English | MEDLINE | ID: mdl-33609087

ABSTRACT

Aging is a physiological process whose underlying mechanisms are still largely unknown. The study of the biochemical transformations associated with aging is crucial for understanding this process and could translate into an improvement of the quality of life of the aging population. Red blood cells (RBCs) are the most abundant cells in humans and are involved in essential functions that could undergo different alterations with age. The present study analyzed the metabolic alterations experienced by RBCs during aging, as well as the influence of obesity and gender in this process. To this end, the metabolic profile of 83 samples from healthy and obese patients was obtained by Nuclear Magnetic Resonance spectroscopy. Multivariate statistical analysis revealed differences between Age-1 (≤45) and Age-2 (>45) subgroups, as well as between BMI-1 (<30) and BMI-2 (≥30) subgroups, while no differences were associated with gender. A general decrease in the levels of amino acids was detected with age, in addition to metabolic alterations of glycolysis, the pentose phosphate pathway, nucleotide metabolism, glutathione metabolism and the Luebering-Rapoport shunt. Obesity also had an impact on the metabolomics profile of RBCs; sometimes mimicking the alterations induced by aging, while, in other cases, its influence was the opposite, suggesting these changes could counteract the adaptation of the organism to senescence.


Subject(s)
Aging/metabolism , Erythrocytes/metabolism , Metabolome/physiology , Obesity/metabolism , Adult , Age Factors , Aged , Female , Healthy Volunteers , Humans , Magnetic Resonance Imaging , Male , Middle Aged
20.
Nucleic Acids Res ; 48(22): 12415-12435, 2020 12 16.
Article in English | MEDLINE | ID: mdl-33167030

ABSTRACT

The current pandemic situation caused by the Betacoronavirus SARS-CoV-2 (SCoV2) highlights the need for coordinated research to combat COVID-19. A particularly important aspect is the development of medication. In addition to viral proteins, structured RNA elements represent a potent alternative as drug targets. The search for drugs that target RNA requires their high-resolution structural characterization. Using nuclear magnetic resonance (NMR) spectroscopy, a worldwide consortium of NMR researchers aims to characterize potential RNA drug targets of SCoV2. Here, we report the characterization of 15 conserved RNA elements located at the 5' end, the ribosomal frameshift segment and the 3'-untranslated region (3'-UTR) of the SCoV2 genome, their large-scale production and NMR-based secondary structure determination. The NMR data are corroborated with secondary structure probing by DMS footprinting experiments. The close agreement of NMR secondary structure determination of isolated RNA elements with DMS footprinting and NMR performed on larger RNA regions shows that the secondary structure elements fold independently. The NMR data reported here provide the basis for NMR investigations of RNA function, RNA interactions with viral and host proteins and screening campaigns to identify potential RNA binders for pharmaceutical intervention.


Subject(s)
COVID-19/prevention & control , Magnetic Resonance Spectroscopy/methods , Nucleic Acid Conformation , RNA, Viral/chemistry , SARS-CoV-2/genetics , 3' Untranslated Regions/genetics , Base Sequence , COVID-19/epidemiology , COVID-19/virology , Frameshifting, Ribosomal/genetics , Genome, Viral/genetics , Humans , Models, Molecular , Pandemics , SARS-CoV-2/physiology
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