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RATIONALE: The accumulation of beta-amyloid peptide (Aß) in the forebrain leads to cognitive dysfunction and neurodegeneration in Alzheimer's disease. Studies have shown that individuals with a consistently cognitively active lifestyle are less vulnerable to Aß toxicity. Recent research has demonstrated that intrahippocampal Aß can impact catecholaminergic release and spatial memory. Interestingly, exposure to novelty stimuli has been found to stimulate the release of catecholamines in the hippocampus. However, it remains uncertain whether repeated enhancing catecholamine activity can effectively alleviate cognitive impairment in individuals with Alzheimer's disease. OBJECTIVES: Our primary aim was to investigate whether repeated exposure to novelty could enable cognitive resilience against Aß. This protection could be achieved by modulating catecholaminergic activity within the hippocampus. METHODS: To investigate this hypothesis, we subjected mice to three different conditions-standard housing (SH), repeated novelty (Nov), or daily social interaction (Soc) for one month. We then infused saline solution (SS) or Aß (Aß1-42) oligomers intrahippocampally and measured spatial memory retrieval in a Morris Water Maze (MWM). Stereological analysis and extracellular baseline dopamine levels using in vivo microdialysis were assessed in independent groups of mice. RESULTS: The mice that received Aß1-42 intrahippocampal infusions and remained in SH or Soc conditions showed impaired spatial memory retrieval. In contrast, animals subjected to the Nov protocol demonstrated remarkable resilience, showing strong spatial memory expression even after Aß1-42 intrahippocampal infusion. The stereological analysis indicated that the Aß1-42 infusion reduced the tyrosine hydroxylase axonal length in SH or Soc mice compared to the Nov group. Accordingly, the hippocampal extracellular dopamine levels increased significantly in the Nov groups. CONCLUSIONS: These compelling results demonstrate the potential for repeated novelty exposure to strengthen the dopaminergic system and mitigate the toxic effects of Aß1-42. They also highlight new and promising therapeutic avenues for treating and preventing AD, especially in its early stages.
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This study investigated crotamine (CTA), a peptide derived from the venom of the South American rattlesnake Crotalus durissus terrificus, known for its exceptional cell penetration potential. The objective was to explore the antibacterial and antifungal activity of CTA, its ability to inhibit efflux pumps and evaluate the effectiveness of its pharmacological combination with antibiotics and antifungals. In microbiological assays, CTA in combination with antibiotics was tested against strains of S. aureus and the inhibition of NorA, Tet(K) and MepA efflux pumps was also evaluated. CTA alone did not present clinically relevant direct antibacterial action, presenting MIC > 209.7 µM against strains S. aureus 1199B, IS-58, K2068. The standard efflux pump inhibitor CCCP showed significant effects in all negative relationships to assay reproducibility. Against the S. aureus 1199B strain, CTA (20.5 µM) associated with norfloxacin diluted 10 × (320.67 µM) showed a potentiating effect, in relation to the control. Against the S. aureus IS-58 strain, the CTA associated with tetracycline did not show a significant combinatorial effect, either with 2304 or 230.4 µM tetracycline. CTA at a concentration of 2.05 µM associated with ciprofloxacin at a concentration of 309.4 µM showed a significant potentiating effect. In association with EtBr, CTA at concentrations of 2.05 and 20.5 µM potentiated the effect in all strains tested, reducing the prevention of NorA, Tet(K) and MepA efflux pumps. In the C. albicans strain, a potentiating effect of fluconazole (334.3 µM) was observed when combined with CTA (2.05 µM). Against the C. tropicalis strain, a significant effect was also observed in the association of fluconazole 334.3 µM, where CTA 2.05 µM considerably reduced fungal growth and decreased the potentiation of fluconazole. Against the C. krusei strain, no significant potentiating effect of fluconazole was obtained by CTA. Our results indicate that CTA in pharmacological combination potentiates the effects of antibiotics and antifungal. This represents a new and promising antimicrobial strategy for treating a wide variety of infections.
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Antibacterianos , Antifúngicos , Venenos de Crotalídeos , Crotalus , Testes de Sensibilidade Microbiana , Antifúngicos/farmacologia , Antifúngicos/química , Antibacterianos/farmacologia , Venenos de Crotalídeos/farmacologia , Animais , Staphylococcus aureus/efeitos dos fármacos , Sinergismo Farmacológico , Candida albicans/efeitos dos fármacos , Serpentes PeçonhentasRESUMO
AIM: Tirzepatide (Tzp), a novel dual agonist glucose-dependent insulinotropic polypeptide/glucagon-like peptide-1, is approved for treating insulin resistance and obesity, and menopausal women consuming a high-calorie diet are a target to study the Tzp effect. Therefore, we aimed to allometrically scale body weight (BW) in Tzp-treated obese diabetic menopausal mice. MATERIALS AND METHODS: Three-month-old C57BL/6 female mice had bilateral ovariectomy (Ovx) or a sham procedure and for 12 weeks were fed a control diet or a high-fat and high sucrose diet (n = 120/each group [control (C), obese diabetic (Od), Ovx (O), sham (S), Tzp (T)]). Tzp was subcutaneously administered (10 nmol/kg) or vehicle once a day for an additional 4 weeks. The analysis considered log-transformed data and the allometric equation log y = log a + b log x. RESULTS: Od and OdO showed more upward slopes than C and CO. In C, BW was non-allometric by T administration. Od and OdO showed slightly positive slopes (more prominent in OdO than Od). OdT and OdOT showed negative slopes, significant intercepts, and more robust Pearson coefficients than untreated ones. A potent drug effect was seen with BW allometric decline. Interactions between diet versus Ovx and diet versus Tzp affected weight gain. Diet versus Ovx versus Tzp affected food intake. CONCLUSIONS: A model was developed to show three usual factors observed in mature women. Notably, Tzp improved the metabolism and weight loss of OdO mice. Tzp-treated mice showed negative allometric BW across treatment time, which is a quantitative assessment that allows better comparison between results.
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Adiponectina , Diabetes Mellitus Tipo 2 , Receptor do Peptídeo Semelhante ao Glucagon 1 , Insulina , Leptina , Menopausa , Camundongos Endogâmicos C57BL , Obesidade , Animais , Feminino , Obesidade/tratamento farmacológico , Menopausa/efeitos dos fármacos , Diabetes Mellitus Tipo 2/tratamento farmacológico , Camundongos , Adiponectina/sangue , Leptina/sangue , Receptor do Peptídeo Semelhante ao Glucagon 1/agonistas , Receptor do Peptídeo Semelhante ao Glucagon 1/metabolismo , Insulina/sangue , Peso Corporal/efeitos dos fármacos , Dieta Hiperlipídica/efeitos adversos , Polipeptídeo Inibidor Gástrico/uso terapêutico , Ovariectomia , Receptor do Peptídeo Semelhante ao Glucagon 2RESUMO
Chagas disease, leishmaniasis, and malaria are major parasitic diseases disproportionately affecting the underprivileged population in developing nations. Finding new, alternative anti-parasitic compounds to treat these diseases is crucial because of the limited number of options currently available, the side effects they cause, the need for long treatment courses, and the emergence of drug-resistant parasites. Anti-microbial peptides (AMPs) derived from amphibian skin secretions are small bioactive molecules capable of lysing the cell membrane of pathogens while having low toxicity against human cells. Here, we report the anti-parasitic activity of five AMPs derived from skin secretions of three Ecuadorian frogs: cruzioseptin-1, cruzioseptin-4 (CZS-4), and cruzioseptin-16 from Cruziohyla calcarifer; dermaseptin-SP2 from Agalychnis spurrelli; and pictuseptin-1 from Boana picturata. These five AMPs were chemically synthesized. Initially, the hemolytic activity of CZS-4 and its minimal inhibitory concentration against Escherichia coli, Staphylococcus aureus, and Candida albicans were determined. Subsequently, the cytotoxicity of the synthetic AMPs against mammalian cells and their anti-parasitic activity against Leishmania mexicana promastigotes, erythrocytic stages of Plasmodium falciparum and mammalian stages of Trypanosoma cruzi were evaluated in vitro. The five AMPs displayed activity against the pathogens studied, with different levels of cytotoxicity against mammalian cells. In silico molecular docking analysis suggests this bioactivity may occur via pore formation in the plasma membrane, resulting in microbial lysis. CZS-4 displayed anti-bacterial, anti-fungal, and anti-parasitic activities with low cytotoxicity against mammalian cells. Further studies about this promising AMP are required to gain a better understanding of its activity.IMPORTANCEChagas disease, malaria, and leishmaniasis are major tropical diseases that cause extensive morbidity and mortality, for which available treatment options are unsatisfactory because of limited efficacy and side effects. Frog skin secretions contain molecules with anti-microbial properties known as anti-microbial peptides. We synthesized five peptides derived from the skin secretions of different species of tropical frogs and tested them against cultures of the causative agents of these three diseases, parasites known as Trypanosoma cruzi, Plasmodium falciparum, and Leishmania mexicana. All the different synthetic peptides studied showed activity against one of more of the parasites. Peptide cruzioseptin-4 is of special interest since it displayed intense activity against parasites while being innocuous against cultured mammalian cells, which indicates it does not simply hold general toxic properties; rather, its activity is specific against the parasites.
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Anuros , Leishmania mexicana , Plasmodium falciparum , Pele , Trypanosoma cruzi , Animais , Trypanosoma cruzi/efeitos dos fármacos , Plasmodium falciparum/efeitos dos fármacos , Humanos , Leishmania mexicana/efeitos dos fármacos , Pele/parasitologia , Pele/efeitos dos fármacos , Testes de Sensibilidade Microbiana , Peptídeos Catiônicos Antimicrobianos/farmacologia , Peptídeos Catiônicos Antimicrobianos/química , Peptídeos Antimicrobianos/farmacologia , Peptídeos Antimicrobianos/química , Proteínas de Anfíbios/farmacologia , Proteínas de Anfíbios/química , Equador , Doença de Chagas/tratamento farmacológicoRESUMO
INTRODUCTION: Leukocytoclastic vasculitis (LCV) is a small vessel vasculitis involving arterioles, capillaries and postcapillary venules. LCV is generally confined to the skin, with extracutaneous manifestations occurring less frequently. LCV has multiple potential etiologies. Indeed, histological LCV can be found in anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis, immune complex vasculitis, vasculitis associated with systemic diseases (i.e. sarcoidosis, Sjögren's syndrome, rheumatoid arthritis, and systemic lupus erythematosus), or in vasculitis associated with cancer, infections, sepsis and use of certain medications. LCV can also be idiopathic in up to 50% of cases. CASE REPORT: Semaglutide is a glucagon-like peptide 1 (GLP-1) receptor agonist used for management of type 2 diabetes mellitus (T2DM), obesity and overweight associated with one or more weight-related comorbidities. A case of drug-induced LCV has already been described with the use of once-daily oral semaglutide. Herein, we describe the first case of skin-limited LCV induced by once-weekly subcutaneous semaglutide in a 73-year-old man with T2DM, who experienced the complete resolution of the skin lesions shortly after the discontinuation of semaglutide therapy. CONCLUSION: Future prospective studies, adverse event reporting and post-marketing surveillance will certainly contribute to establishing if LCV represents a less rare than expected side effect of both oral and subcutaneous semaglutide formulations.
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Diabetes Mellitus Tipo 2 , Peptídeos Semelhantes ao Glucagon , Vasculite Leucocitoclástica Cutânea , Humanos , Masculino , Peptídeos Semelhantes ao Glucagon/efeitos adversos , Peptídeos Semelhantes ao Glucagon/administração & dosagem , Idoso , Diabetes Mellitus Tipo 2/tratamento farmacológico , Diabetes Mellitus Tipo 2/complicações , Vasculite Leucocitoclástica Cutânea/induzido quimicamente , Vasculite Leucocitoclástica Cutânea/tratamento farmacológico , Vasculite Leucocitoclástica Cutânea/patologia , Injeções Subcutâneas , Hipoglicemiantes/efeitos adversos , Hipoglicemiantes/administração & dosagemRESUMO
CONTEXT: Molecularly imprinted polymers (MIPs) have promising applications as synthetic antibodies for protein and peptide recognition. A critical aspect of MIP design is the selection of functional monomers and their adequate proportions to achieve materials with high recognition capacity toward their targets. To contribute to this goal, we calibrated a molecular dynamics protocol to reproduce the experimental trends in peptide recognition of 13 pre-polymerization mixtures reported in the literature for the peptide toxin melittin. METHODS: Three simulation conditions were tested for each mixture by changing the box size and the number of monomers and cross-linkers surrounding the template in a solvent-explicit environment. Fully atomistic MD simulations of 350 ns were conducted with the AMBER20 software, with ff19SB parameters for the peptide, gaff2 parameters for the monomers and cross-linkers, and the OPC water model. Template-monomer interaction energies under the LIE approach showed significant differences between high-affinity and low-affinity mixtures. Simulation systems containing 100 monomers plus cross-linkers in a cubic box of 90 Å3 successfully ranked the mixtures according to their experimental performance. Systems with higher monomer densities resulted in non-specific intermolecular contacts that could not account for the experimental trends in melittin recognition. The mixture with the best recognition capacity showed preferential binding to the 13-26-α-helix, suggesting a relevant role for this segment in melittin imprinting and recognition. Our findings provide insightful information to assist the computational design of molecularly imprinted materials with a validated protocol that can be easily extended to other templates.
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Simulação de Dinâmica Molecular , Peptídeos , Peptídeos/química , Meliteno/química , Polimerização , Polímeros Molecularmente Impressos/química , Impressão Molecular/métodosRESUMO
INTRODUCTION: The proline-rich decapeptide 10c (Bj-PRO-10c; ENWPHPQIPP) from the Bothrops jararaca snake modulates argininosuccinate synthetase (AsS) activity to stimulate L-arginine metabolite production and neuroprotection in the SH-SY5Y cell line. The relationships between structure, interactions with AsS, and neuroprotection are little known. We evaluated the neuroprotective effects of Bj-PRO-10c and three other PROs (Bn-PRO-10a,
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Canine distemper virus (CDV) affects many domestic and wild animals. Variations among CDV genome linages could lead to vaccination failure. To date, there are several vaccine alternatives, such as a modified live virus and a recombinant vaccine; however, most of these alternatives are based on the ancestral strain Onderstepoort, which has not been circulating for years. Vaccine failures and the need to update vaccines have been widely discussed, and the development of new vaccine candidates is necessary to reduce circulation and mortality. Current vaccination alternatives cannot be used in wildlife animals due to the lack of safety data for most of the species, in addition to the insufficient immune response against circulating strains worldwide in domestic species. Computational tools, including peptide-based therapies, have become essential for developing new-generation vaccines for diverse models. In this work, a peptide-based vaccine candidate with a peptide library derived from CDV H and F protein consensus sequences was constructed employing computational tools. The molecular docking and dynamics of the selected peptides with canine MHC-I and MHC-II and with TLR-2 and TLR-4 were evaluated. In silico safety was assayed through determination of antigenicity, allergenicity, toxicity potential, and homologous canine peptides. Additionally, in vitro safety was also evaluated through cytotoxicity in cell lines and canine peripheral blood mononuclear cells (cPBMCs) and through a hemolysis potential assay using canine red blood cells. A multiepitope CDV polypeptide was constructed, synthetized, and evaluated in silico and in vitro by employing the most promising peptides for comparison with single CDV immunogenic peptides. Our findings suggest that predicting immunogenic CDV peptides derived from most antigenic CDV proteins could aid in the development of new vaccine candidates, such as multiple single CDV peptides and multiepitope CDV polypeptides, that are safe in vitro and optimized in silico. In vivo studies are being conducted to validate potential vaccines that may be effective in preventing CDV infection in domestic and wild animals.
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Vírus da Cinomose Canina , Cinomose , Vacinas Virais , Vírus da Cinomose Canina/imunologia , Animais , Cães , Vacinas Virais/imunologia , Cinomose/prevenção & controle , Cinomose/imunologia , Simulação de Acoplamento Molecular , Peptídeos/imunologia , Peptídeos/química , Vacinas de Subunidades Antigênicas/imunologia , Proteínas Virais de Fusão/imunologiaRESUMO
To gain insight into the functional relationship between the nucleocapsid (NC) domains of the Gag polyproteins of feline and simian immunodeficiency viruses, FIV and SIV, respectively, we generated two FIV Gag chimeric proteins containing different SIV NC and gag sequences. A chimeric FIV Gag protein (NC1) containing the SIV two zinc fingers motifs was incapable of assembling into virus-like particles. By contrast, another Gag chimera (NC2) differing from NC1 by the replacement of the C-terminal region of the FIV NC with SIV SP2 produced particles as efficiently as wild-type FIV Gag. Of note, when the chimeric NC2 Gag polyprotein was expressed in the context of the proviral DNA in feline CrFK cells, wild-type levels of virions were produced which encapsidated 50% of genomic RNA when compared to the wild-type virus.
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Produtos do Gene gag , Vírus da Imunodeficiência Felina , Vírus da Imunodeficiência Símia , Montagem de Vírus , Dedos de Zinco , Animais , Vírus da Imunodeficiência Felina/genética , Vírus da Imunodeficiência Felina/metabolismo , Vírus da Imunodeficiência Felina/fisiologia , Produtos do Gene gag/genética , Produtos do Gene gag/metabolismo , Produtos do Gene gag/química , Vírus da Imunodeficiência Símia/genética , Vírus da Imunodeficiência Símia/fisiologia , Gatos , Proteínas Recombinantes de Fusão/genética , Proteínas Recombinantes de Fusão/metabolismo , Proteínas Recombinantes de Fusão/química , Linhagem Celular , Nucleocapsídeo/metabolismo , Nucleocapsídeo/genética , Proteínas do Nucleocapsídeo/genética , Proteínas do Nucleocapsídeo/metabolismo , FenótipoRESUMO
The diagnosis of tegumentary leishmaniasis (TL) is hampered by variable sensitivity and/or specificity of the tests. Serological assays are suitable to diagnose visceral leishmaniasis (VL); however, they present low performance for the detection of TL cases. Additionally, blood collection to obtain patient serum represents a challenge, as it is an invasive and uncomfortable procedure, requiring laboratorial infrastructure and trained professionals. In this context, the present study proposed to evaluate patient urine to detect TL, given that this analyte has proven to be effective in ELISA experiments for the detection of VL cases. For this, a Leishmania protein called LiHyV, two specific B-cell epitopes derived from protein amino acid sequence, and a Leishmania antigenic extract (SLA) were used as antigens. A total of 215 paired urine and serum samples were evaluated, and results showed that, when serum was employed as an analyte, rLiHyV, Peptide1, Peptide2, and SLA presented a sensitivity of 85 %, 29 %, 58 %, and 31 %, respectively, and a specificity of 97.5 %, 98 %, 100 %, and 97.5 %, respectively, in the diagnosis of TL. When urine was used, rLiHyV, Peptide1, Peptide2, and SLA presented a sensitivity of 95 %, 74 %, 67 %, and 52 %, respectively, and a specificity of 100 %, 99 %, 98 %, and 86 %, respectively. In conclusion, preliminary data suggest that urine could be considered as an alternative biological sample for the detection of TL cases.