RESUMO
BACKGROUND: Serratia marcescens becomes an apparent nosocomial pathogen and causes a variety of infections. S. marcescens possess various virulence factors that are regulated by intercellular communication system quorum sensing (QS). Targeting bacterial virulence is a proposed strategy to overcome bacterial resistance. Sitagliptin anti-QS activity has been demonstrated previously and we aimed in this study to investigate the effects of antidiabetic drugs vildagliptin and metformin compared to sitagliptin on S. marcescens pathogenesis. METHODS: We assessed the effects of tested drugs in subinhibitory concentrations phenotypically on the virulence factors and genotypically on the virulence encoding genes' expressions. The protection of tested drugs on S. marcescens pathogenesis was performed in vivo. Molecular docking study has been conducted to evaluate the interference capabilities of tested drugs to the SmaR QS receptor. RESULTS: Vildagliptin reduced the expression of virulence encoding genes but did not show in vitro or in vivo anti-virulence activities. Metformin reduced the expression of virulence encoding genes and inhibited bacterial virulence in vitro but did not show in vivo protection. Sitagliptin significantly inhibited virulence factors in vitro, reduced the expression of virulence factors and protected mice from S. marcescens. Docking study revealed that sitagliptin is more active than metformin and fully binds to SmaR receptor, whereas vildagliptin had single interaction to SmaR. CONCLUSION: The downregulation of virulence genes was not enough to show anti-virulence activities. Hindering of QS receptors may play a crucial role in diminishing bacterial virulence.
Assuntos
Antibacterianos/farmacologia , Reposicionamento de Medicamentos , Hipoglicemiantes/farmacologia , Infecções por Serratia/tratamento farmacológico , Serratia marcescens/efeitos dos fármacos , Animais , Antibacterianos/química , Proteínas de Bactérias/química , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Feminino , Regulação Bacteriana da Expressão Gênica/efeitos dos fármacos , Humanos , Hipoglicemiantes/química , Metformina/química , Metformina/farmacologia , Camundongos , Simulação de Acoplamento Molecular , Infecções por Serratia/microbiologia , Serratia marcescens/genética , Serratia marcescens/patogenicidade , Serratia marcescens/fisiologia , Vildagliptina/química , Vildagliptina/farmacologia , Virulência/efeitos dos fármacos , Fatores de Virulência/química , Fatores de Virulência/genética , Fatores de Virulência/metabolismoRESUMO
BACKGROUND: The presence of impurities in some drugs may compromise the safety and efficacy of the patient's treatment. Therefore, establishing of the biological safety of the impurities is essential. Diabetic patients are predisposed to tissue damage due to an increased oxidative stress process; and drug impurities may contribute to these toxic effects. In this context, the aim of this work was to study the toxicity, in 3 T3 cells, of the antidiabetic agents sitagliptin, vildagliptin, and their two main impurities of synthesis (S1 and S2; V1 and V2, respectively). METHODS: MTT reduction and neutral red uptake assays were performed in cytotoxicity tests. In addition, DNA damage (measured by comet assay), intracellular free radicals (by DCF), NO production, and mitochondrial membrane potential (ΔψM) were evaluated. RESULTS: Cytotoxicity was observed for impurity V2. Free radicals generation was found at 1000 µM of sitagliptin and 10 µM of both vildagliptin impurities (V1 and V2). A decrease in NO production was observed for all vildagliptin concentrations. No alterations were observed in ΔψM or DNA damage at the tested concentrations. CONCLUSIONS: This study demonstrated that the presence of impurities might increase the cytotoxicity and oxidative stress of the pharmaceutical formulations at the concentrations studied.