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Estrogen deficiency induces cardiac dysfunction and increases the risk of cardiovascular disease in postmenopausal women and in those who underwent bilateral oophorectomy. Previous evidence suggests that puerarin, a phytoestrogen, exerts beneficial effects on cardiac function in patients with cardiac hypertrophy. In this study, we investigated whether puerarin could prevent cardiac hypertrophy and remodeling in ovariectomized, aortic-banded rats. Female SD rats subjected to bilateral ovariectomy (OVX) plus abdominal aortic constriction (AAC). The rats were treated with puerarin (50 mg·kg-1 ·d-1, ip) for 8 weeks. Then echocardiography was assessed, and the rats were sacrificed, their heart tissues were extracted and allocated for further experiments. We showed that puerarin administration significantly attenuated cardiac hypertrophy and remodeling in AAC-treated OVX rats, which could be attributed to activation of PPARα/PPARγ coactivator-1 (PGC-1) pathway. Puerarin administration significantly increased the expression of estrogen-related receptor α, nuclear respiratory factor 1, and mitochondrial transcription factor A in hearts. Moreover, puerarin administration regulated the expression of metabolic genes in AAC-treated OVX rats. Hypertrophic changes could be induced in neonatal rat cardiomyocytes (NRCM) in vitro by treatment with angiotensin II (Ang II, 1 µM), which was attenuated by co-treatemnt with puerarin (100 µM). We further showed that puerarin decreased Ang II-induced accumulation of non-esterified fatty acids (NEFAs) and deletion of ATP, attenuated the Ang II-induced dissipation of the mitochondrial membrane potential, and improved the mitochondrial dysfunction in NRCM. Furthermore, addition of PPARα antagonist GW6471 (10 µM) partially abolished the anti-hypertrophic effects and metabolic effects of puerarin in NRCM. In conclusion, puerarin prevents cardiac hypertrophy in AAC-treated OVX rats through activation of PPARα/PGC-1 pathway and regulation of energy metabolism remodeling. This may provide a new approach to prevent the development of heart failure in postmenopausal women.
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Cardiomegalia/prevenção & controle , Cardiotônicos/uso terapêutico , Isoflavonas/uso terapêutico , Transdução de Sinais/efeitos dos fármacos , Angiotensina II/farmacologia , Animais , Aorta Abdominal/patologia , Cardiomegalia/etiologia , Cardiomegalia/patologia , Constrição Patológica/complicações , Metabolismo Energético/efeitos dos fármacos , Feminino , Miocárdio/patologia , Miócitos Cardíacos/efeitos dos fármacos , Ovariectomia , PPAR alfa/metabolismo , Coativador 1-alfa do Receptor gama Ativado por Proliferador de Peroxissomo/metabolismo , Ratos Sprague-DawleyRESUMO
Filamenting temperature-sensitive mutant Z (FtsZ) is recognized as a promising target for new antibiotics development because of its high conservatism and pivotal role in the bacteria cell division. The aromatic heterocyclic scaffold of indole is known showing merit medical functions in antiviral and antimicrobial. In the present study, a series of 1-methylquinolinium derivatives, which were integrated with an indole fragment at its 2-position and a variety of amino groups (cyclic or linear, mono- or di-amine) at the 4-position were synthesized and their antibacterial activities were evaluated. The results of antibacterial study show that the representative compounds can effectively inhibit the growth of testing strains including MRSA and VRE, with MIC values of 1-4⯵g/mL by bactericidal mode. The mode of action assays revealed that c2 can effectively disrupt the rate of GTP hydrolysis and dynamic polymerization of FtsZ, and thus inhibits bacterial cell division and then causes bacterial cell death. In addition, the result of resistance generation experiment reveals that c2 is not likely to induce resistance in S. aureus.
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Antibacterianos/farmacologia , Bactérias Gram-Negativas/efeitos dos fármacos , Bactérias Gram-Positivas/efeitos dos fármacos , Indóis/farmacologia , Compostos de Quinolínio/farmacologia , Antibacterianos/síntese química , Antibacterianos/química , Relação Dose-Resposta a Droga , Farmacorresistência Bacteriana/efeitos dos fármacos , Indóis/química , Testes de Sensibilidade Microbiana , Estrutura Molecular , Compostos de Quinolínio/química , Relação Estrutura-AtividadeRESUMO
The antibacterial activity and the synergistic effect with ß-lactam antibiotics of a new 1-methylquinolinium iodide derivative were investigated. The experimental results indicate that the compound possesses a strong antibacterial activity against a panel of bacteria including methicillin-resistant Staphylococcus aureus, vancomycin-resistant Enterococcus and NDM-1 Escherichia coli with the MIC values from 0.75 µg/mL to 6 µg/mL. In addition, this compound combined with ß-lactam antibiotics shows strong synergistic antimicrobial activities against antibiotic-resistant strains of S. aureus. The results of biochemical studies also reveal that this compound can effectively disrupt GTPase activity, polymerization of FtsZ, and cell division to cause cell death. The compound shows high potential for further development as a new generation of antibacterial agents to fight against the emergence of multidrug-resistant bacteria.
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Antibacterianos/farmacologia , Proteínas de Bactérias/antagonistas & inibidores , Proteínas do Citoesqueleto/antagonistas & inibidores , Escherichia coli/efeitos dos fármacos , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Compostos de Quinolínio/farmacologia , Enterococos Resistentes à Vancomicina/efeitos dos fármacos , beta-Lactamas/farmacologia , Proteínas de Bactérias/metabolismo , Divisão Celular/efeitos dos fármacos , Proteínas do Citoesqueleto/metabolismo , Relação Dose-Resposta a Droga , Farmacorresistência Bacteriana , Sinergismo Farmacológico , Escherichia coli/enzimologia , GTP Fosfo-Hidrolases/metabolismo , Staphylococcus aureus Resistente à Meticilina/citologia , Polimerização/efeitos dos fármacos , beta-LactamasesRESUMO
The increasing incidence of multidrug resistant bacterial infection renders an urgent need for the development of new antibiotics. To develop small molecules disturbing FtsZ activity has been recognized as promising approach to search for antibacterial of high potency systematically. Herein, a series of novel quinolinium derivatives were synthesized and their antibacterial activities were investigated. The compounds show strong antibacterial activities against different bacteria strains including MRSA, VRE and NDM-1 Escherichia coli. Among these derivatives, a compound bearing a 4-fluorophenyl group (A2) exhibited a superior antibacterial activity and its MICs to the drug-resistant strains are found lower than those of methicillin and vancomycin. The biological results suggest that these quinolinium derivatives can disrupt the GTPase activity and dynamic assembly of FtsZ, and thus inhibit bacterial cell division and then cause bacterial cell death. These compounds deserve further evaluation for the development of new antibacterial agents targeting FtsZ.
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Antibacterianos/farmacologia , Escherichia coli/efeitos dos fármacos , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Quinolinas/farmacologia , Tiazóis/farmacologia , Enterococos Resistentes à Vancomicina/efeitos dos fármacos , Animais , Antibacterianos/síntese química , Antibacterianos/química , Morte Celular/efeitos dos fármacos , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Relação Dose-Resposta a Droga , Escherichia coli/citologia , Humanos , Staphylococcus aureus Resistente à Meticilina/citologia , Camundongos , Testes de Sensibilidade Microbiana , Estrutura Molecular , Quinolinas/síntese química , Quinolinas/química , Relação Estrutura-Atividade , Tiazóis/síntese química , Tiazóis/química , Enterococos Resistentes à Vancomicina/citologiaRESUMO
The emergence of Panton-Valentine leukocidin (PVL)-positive methicillin-resistant Staphylococcus aureus (MRSA) is a public health concern worldwide. PVL is associated with community-associated MRSA and is linked to skin and soft tissue infections (SSTIs). However, PVL genes have also been detected in health care-associated (HA) MRSA isolates. The diseases associated with PVL-positive HA-MRSA isolates and the distributions of PVL-encoding bacteriophages in HA-MRSA have not been determined. In this study, a total of 259 HA-MRSA strains isolated between 2009 and 2012 in China from inpatients with SSTIs, pneumonia, and bacteremia were selected for molecular typing, including staphylococcal cassette chromosome mec typing, multilocus sequence typing, and staphylococcal protein A gene typing. The PVL genes and PVL bacteriophages in the MRSA isolates were characterized by PCR. Among the tested MRSA isolates, 28.6% (74/259) were PVL positive. The high prevalence of PVL-carrying HA-MRSA was observed to be associated with SSTIs but not with pneumonia or bacteremia. The PVL-positive HA-MRSA isolates were colonized mainly by infective PVL phages, namely, Φ7247PVL, ΦSLT, and ΦSa2958. The distribution of PVL-carrying bacteriophages differed geographically. Our study highlights the potential risk of the emergence of multidrug-resistant HA-MRSA strains with increased virulence.
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Toxinas Bacterianas/genética , Infecção Hospitalar , Exotoxinas/genética , Leucocidinas/genética , Staphylococcus aureus Resistente à Meticilina/genética , Staphylococcus aureus Resistente à Meticilina/virologia , Dermatopatias Bacterianas/microbiologia , Infecções dos Tecidos Moles/microbiologia , Infecções Estafilocócicas/microbiologia , Fagos de Staphylococcus/genética , Adulto , Idoso , Idoso de 80 Anos ou mais , China , Feminino , Genótipo , Humanos , Masculino , Staphylococcus aureus Resistente à Meticilina/classificação , Pessoa de Meia-Idade , Tipagem de Sequências Multilocus , Estudos RetrospectivosRESUMO
Multidrug resistant bacteria have been a global health threat currently and frontline clinical treatments for these infections are very limited. To develop potent antibacterial agents with new bactericidal mechanisms is thus needed urgently to address this critical antibiotic resistance challenge. Natural products are a treasure of small molecules with high bioactive and low toxicity. In the present study, we demonstrated that a natural compound, honokiol, showed potent antibacterial activity against a number of Gram-positive bacteria including MRSA and VRE. Moreover, honokiol in combination with clinically used ß-lactam antibiotics exhibits strong synergistic antimicrobial effects against drug-resistant S. aureus strains. Biochemical studies further reveal that honokiol may disrupt the GTPase activity, FtsZ polymerization, cell division. These biological impacts induced by honokiol may ultimately cause bacterial cell death. The in vivo antibacterial activity of honokiol against S. aureus infection was also verified with a biological model of G. mellonella larvae. The in vivo results support that honokiol is low toxic against the larvae and effectively increases the survival rate of the larvae infected with S. aureus. These findings demonstrate the potential of honokiol for further structural advancement as a new class of antibacterial agents with high potency against multidrug-resistant bacteria.
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OBJECTIVES: Methicillin-resistant Staphylococcus aureus (MRSA) infection is increasing and causing global concern. The mechanism of MRSA resistance to amikacin is poorly understood. We report on the first matched-pair study to reveal that the phenotypic cell wall thickening of MRSA is associated with adaptive resistance to amikacin. METHODS: Two MRSA strains (CY001 and CY002) were isolated from blood and synovial fluid samples, respectively, from a 12-year-old male patient with osteomyelitis. The strains were subjected to a matched-pair study, including antimicrobial agent susceptibility determination, molecular typing, morphological observation and in vitro resistance induction. RESULTS: Both strains are Panton-Valentine leucocidin-positive, multilocus sequence type 59, staphylococcal cassette chromosome mec type IV and spa type 437 MRSA with identical PFGE profiles. The drug susceptibility spectra of the two isolates are similar. However, CY001 is resistant to amikacin (CY001-AMI(R); MICâ=â64 mg/L), contrary to the susceptible CY002 (CY002-AMI(S); MICâ=â8 mg/L). CY001-AMI(R) may have developed adaptive resistance, because it lacks aminoglycoside-modifying enzymes and has an altered growth curve. Interestingly, CY001-AMI(R) has a thicker cell wall (36.43â±â4.25 nm) than CY002-AMI(S) (18.15â±â3.74 nm) in the presence of amikacin at its MIC. The thickened cell wall can also be observed in an in vitro-induced strain (CY002-AMI(R)) in the presence of amikacin at its MIC (36.78â±â3.41 nm); this strain was obtained by gradually increasing the amount of amikacin. However, the cell wall-thickened strains cultured in the presence of amikacin are still susceptible to vancomycin. CONCLUSIONS: Cell wall thickening is associated with adaptive resistance in MRSA and alternative antibiotics can be used to treat patients when adaptive resistance to amikacin has developed.
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Amicacina/farmacologia , Antibacterianos/farmacologia , Parede Celular/efeitos dos fármacos , Parede Celular/ultraestrutura , Farmacorresistência Bacteriana , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Staphylococcus aureus Resistente à Meticilina/ultraestrutura , Sangue/microbiologia , Criança , Eletroforese em Gel de Campo Pulsado , Humanos , Masculino , Staphylococcus aureus Resistente à Meticilina/isolamento & purificação , Testes de Sensibilidade Microbiana , Microscopia Eletrônica de Transmissão , Tipagem Molecular , Osteomielite/microbiologia , Infecções Estafilocócicas/microbiologia , Líquido Sinovial/microbiologiaRESUMO
OBJECTIVES: The distribution of methicillin-resistant Staphylococcus aureus (MRSA) clones is dynamic and geographically unique. To understand the changing epidemiology of MRSA infections in China, we performed a prospective, multicity surveillance study with molecular typing and phenotypic analysis to determine the association of major prevalent clones with their antimicrobial resistance profiles. METHODS: A total of 517 S. aureus isolates collected between January 2009 and March 2012 from six cities in China were subjected to antibiogram analysis and molecular typing, including staphylococcal cassette chromosome mec typing, multilocus sequence typing, staphylococcal protein A gene typing and PFGE typing. RESULTS: Among the isolates collected, 309 were characterized as MRSA, with a prevalence of 59.8%. Three major clones were found to be prevalent in China: ST239-MRSA-III-t030, ST239-MRSA-III-t037 and ST5-MRSA-II-t002. These three clones were associated with two characteristic resistance profiles, namely, gentamicin/ciprofloxacin/rifampicin/levofloxacin for the first clone and gentamicin/ciprofloxacin/clindamycin/erythromycin/tetracycline/levofloxacin/trimethoprim/sulfamethoxazole for the latter two. Several geographically unique minor clones were also identified. CONCLUSIONS: The predominant MRSA clones in China were associated with characteristic antimicrobial resistance profiles. Antibiotics for treating patients with MRSA infections can be selected based on the strain typing data.
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Antibacterianos/farmacologia , Farmacorresistência Bacteriana , Staphylococcus aureus Resistente à Meticilina/classificação , Staphylococcus aureus Resistente à Meticilina/isolamento & purificação , Tipagem Molecular , Infecções Estafilocócicas/epidemiologia , Infecções Estafilocócicas/microbiologia , China/epidemiologia , Genótipo , Humanos , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Staphylococcus aureus Resistente à Meticilina/genética , Testes de Sensibilidade Microbiana , Epidemiologia Molecular , PrevalênciaRESUMO
Staphylococcus aureus (S. aureus) is one of the important human pathogens and causes both superficial and systemic infections. More importantly, the formation of S. aureus biofilms, a main cause of its pathogenicity and drug resistance, has been a critical challenge in clinical treatment. Carvacrol, a plant-based natural product, has gained great interest for therapeutic purposes due to its effective biological activity with low cytotoxicity. The present study aimed to investigate the effect of carvacrol on anti-biofilm activity. Growth curve analysis showed that applying a sub-inhibitory concentration of carvacrol (4 µg mL-1) was not lethal to S. aureus SYN; however, the inhibition rate of biofilm formation was as high as 63.6%, and the clearance rate of mature biofilms was as high as 30.7%. In addition, carvacrol effectively reduced the production of biofilm-associated extracellular polysaccharides and showed no effect on eDNA release. Furthermore, qPCR analysis revealed that carvacrol significantly down-regulated the expression of icaA, icaB, icaC, agrA, and sarA (P < 0.05). The in vivo efficacy of carvacrol against biofilm infection was further verified with a biological model of G. mellonella larvae. The results showed that carvacrol was non-toxic to the larvae and can effectively increase the survival rate of the larvae infected with S. aureus strain SYN.
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Catabolite control protein A (CcpA), an important global regulatory protein, is extensively found in S. aureus. Many studies have reported that CcpA plays a pivotal role in regulating the tricarboxylic acid cycle and pathogenicity. Moreover, the CcpA-knockout Staphylococcus aureus (S. aureus) in diabetic mice, compared with the wild-type, showed a reduced colonization rate in the tissues and organs and decreased inflammatory factor expression. However, the effect of CcpA-knockout S. aureus on the host's energy metabolism in a high-glucose environment and its mechanism of action remain unclear. S. aureus, a common and major human pathogen, is increasingly found in patients with obesity and diabetes, as recent clinical data reveal. To address this issue, we generated CcpA-knockout S. aureus strains with different genetic backgrounds to conduct in-depth investigations. In vitro experiments with high-glucose-treated cells and an in vivo model study with type 1 diabetic mice were used to evaluate the unknown effect of CcpA-knockout strains on both the glucose and lipid metabolism phenotypes of the host. We found that the strains caused an abnormal metabolic phenotype in type 1 diabetic mice, particularly in reducing random and fasting blood glucose and increasing triglyceride and fatty acid contents in the serum. In a high-glucose environment, CcpA-knockout S. aureus may activate the hepatic STAT5/PDK4 pathway and affect pyruvate utilization. An abnormal metabolic phenotype was thus observed in diabetic mice. Our findings provide a better understanding of the molecular mechanism of glucose and lipid metabolism disorders in diabetic patients infected with S. aureus.
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Background: Staphylococcus haemolyticus is an opportunistic pathogen that belongs to coagulase-negative Staphylococci (CoNS). Increasing infection and multi-drug resistance cases caused by this strain have been reported and thus it poses a great health threat. Methods: The third-generation sequencing technology was performed on a S. haemolyticus SH-1 isolated from a clinical sample to analyze the drug resistance genes, which included vancomycin resistance related genes. In addition, antimicrobial susceptibility tests, transmission electron microscopy and Triton X-100 stimulated autolysis were conducted to understand its biological characteristics. Results: The study shows that this clinical isolate is a vancomycin intermediate-resistant strain. Genome comparison also revealed that WalK(N70K) and WalK(R280Q) mutations may contribute to the vancomycin resistant phenotype. Besides, S. haemolyticus SH-1 exhibit common features of thicker cell wall and decreased autolytic activity. Conclusion: S. haemolyticus SH-1 with WalKR mutations shows typical characteristics of vancomycin resistant strains. Combining the genome features and biological properties, our findings may provide important information for the understanding of the molecular mechanism of S. haemolyticus to vancomycin intermediate-resistance.
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Dengue viruses (DENVs) are mosquito-borne infectious pathogens that pose a serious global public health threat, and at present, no therapy or effective vaccines are available. Choosing suitable units as candidates is fundamental for the development of a dengue subunit vaccine. Domain III of the DENV-2 E protein (EDIII) was chosen in the present study and expressed in Escherichia coli by N-terminal fusion to a bacterial leader (pelB), and C-terminal fusion with a 6×His tag based on the functions of DENV structure proteins, especially the neutralizing epitopes on the envelope E protein. After two-step purification using Ni-NTA affinity and cation-exchange chromatography, the His-tagged EDIII was purified up to 98% homogenicity. This recombinant EDIII was able to trigger high levels of neutralizing antibodies in both BALB/c and C57BL/6 mice. Both the recombinant EDIII and its murine antibodies protected Vero cells from DENV-2 infection. Interestingly, the recombinant EDIII provides at least partial cross-protection against DENV-1 infection. In addition, the EDIII antibodies were able to protect suckling mice from virus challenge in vivo. These data suggest that a candidate molecule based on the small EDIII protein, which has neutralizing epitopes conserved among all 4 DENV serotypes, has important implications.
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Anticorpos Neutralizantes/metabolismo , Vírus da Dengue , Dengue/imunologia , Proteínas do Envelope Viral/metabolismo , Animais , Anticorpos Antivirais/imunologia , Chlorocebus aethiops , Proteção Cruzada , Dengue/prevenção & controle , Dengue/virologia , Vacinas contra Dengue/imunologia , Epitopos/imunologia , Epitopos/metabolismo , Escherichia coli/imunologia , Escherichia coli/metabolismo , Escherichia coli/virologia , Feminino , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Células Vero , Proteínas do Envelope Viral/imunologia , Proteínas do Envelope Viral/isolamento & purificaçãoRESUMO
Bacteria can form biofilms in natural and clinical environments on both biotic and abiotic surfaces. The bacterial aggregates embedded in biofilms are formed by their own produced extracellular matrix. Staphylococcus aureus (S. aureus) is one of the most common pathogens of biofilm infections. The formation of biofilm can protect bacteria from being attacked by the host immune system and antibiotics and thus bacteria can be persistent against external challenges. Therefore, clinical treatments for biofilm infections are currently encountering difficulty. To address this critical challenge, a new and effective treatment method needs to be developed. A comprehensive understanding of bacterial biofilm formation and regulation mechanisms may provide meaningful insights against antibiotic resistance due to bacterial biofilms. In this review, we discuss an overview of S. aureus biofilms including the formation process, structural and functional properties of biofilm matrix, and the mechanism regulating biofilm formation.
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The rapid and accurate diagnostic methods to identify carbapenemase-producing organisms (CPO) is of great importance for controlling the CPO infection. Herein, we have developed a microfluidic chip-based technique to detect CPO and assessed its clinical value in detecting CPO directly from blood cultures (BCs). The detection performance of the microfluidic chip-based LAMP amplification method was analyzed retrospectively on a collection of 192 isolates including molecularly characterized 108 CPO and 84 non-CPO and prospectively on a collection of 133 positive BCs with or without CPO suspicion, respectively. In the retrospective study, the microfluidic chip-based LAMP amplification method exhibited 87.5% accuracy (95% CI [82.0-91.5]), 97.7% sensitivity (95% CI [91.2-99.6]), 78.8% specificity (95% CI [69.5-86.0]), 79.6% positive predictive value (PPV) (95% CI [70.6-86.5]) and 97.6% negative predictive value (NPV) (95% CI [90.9-99.6]). Among the 192 isolates, 22 (11.5%) false-positives (FP) and 2 (1.0%) false negatives (FN) were observed. In the prospective study, the 133 routine isolates of positive BCs including 18 meropenem-resistant CPO and 115 non-CPO were assessed, and 4 FP were observed in non-CPO and CPO, respectively. The current method showed a total detection performance of 94.0% accuracy (95% CI [88.4-97.1]), 100.0% sensitivity (95% CI [73.2-100.0]), 93.2% specificity (95% CI [86.7-96.8]), 63.6% PPV (95% CI [40.8-82.0]) and 100.0% NPV (95% CI [95.8-100.0]). In summary, the microfluidic chip-based LAMP amplification method is reliable for the rapid screening and detection of CPO with high accuracy, sensitivity, and specificity, and could easily be implemented in clinical microbiology laboratories. IMPORTANCE Rapid and accurate identification of CPO may reduce the genetic exchanges among bacteria and prevent further dissemination of carbapenemases to non-CPO. The current method had designed microfluidic chip-based LAMP amplification method for multiplex detection of carbapenemase genes and evaluated the detection performance of the newly method. The current method can rapidly screen and detect CPO with high accuracy, sensitivity, and specificity, and could easily be implemented in clinical microbiology laboratories, as this will reduce the carbapenem resistance issues worldwide.
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Microfluídica , beta-Lactamases , Estudos Retrospectivos , Microfluídica/métodos , Meropeném , Estudos Prospectivos , beta-Lactamases/genética , Proteínas de Bactérias/genética , Bactérias/genéticaRESUMO
Methazolamide (MTZ), a carbonic anhydrase inhibitor, has been shown to inhibit cardiomyocyte hypertrophy and exert a hypoglycemic effect in patients with type 2 diabetes and diabetic db/db mice. However, whether MTZ has a cardioprotective effect in the setting of diabetic cardiomyopathy is not clear. We investigated the effects of MTZ in a mouse model of streptozotocin-induced type 1 diabetes mellitus (T1DM). Diabetic mice received MTZ by intragastric gavage (10, 25, or 50 mg/kg, daily for 16 weeks). In the diabetic group, MTZ significantly reduced both random and fasting blood glucose levels and improved glucose tolerance in a dose-dependent manner. MTZ ameliorated T1DM-induced changes in cardiac morphology and dysfunction. Mechanistic analysis revealed that MTZ blunted T1DM-induced enhanced expression of ß-catenin. Similar results were observed in neonatal rat cardiomyocytes (NRCMs) and adult mouse cardiomyocytes treated with high glucose or Wnt3a (a ß-catenin activator). There was no significant change in ß-catenin mRNA levels in cardiac tissues or NRCMs. MTZ-mediated ß-catenin downregulation was recovered by MG132, a proteasome inhibitor. Immunoprecipitation and immunofluorescence analyses showed augmentation of AXIN1-ß-catenin interaction by MTZ in T1DM hearts and in NRCMs treated with Wnt3a; thus, MTZ may potentiate AXIN1-ß-catenin linkage to increase ß-catenin degradation. Overall, MTZ may alleviate cardiac hypertrophy by mediating AXIN1-ß-catenin interaction to promote degradation and inhibition of ß-catenin activity. These findings may help inform novel therapeutic strategy to prevent heart failure in patients with diabetes.
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Diabetes Mellitus Experimental , Diabetes Mellitus Tipo 1 , Diabetes Mellitus Tipo 2 , Cardiomiopatias Diabéticas , Animais , Proteína Axina/metabolismo , Diabetes Mellitus Experimental/tratamento farmacológico , Diabetes Mellitus Experimental/metabolismo , Diabetes Mellitus Tipo 1/tratamento farmacológico , Diabetes Mellitus Tipo 1/metabolismo , Diabetes Mellitus Tipo 2/metabolismo , Cardiomiopatias Diabéticas/tratamento farmacológico , Cardiomiopatias Diabéticas/metabolismo , Cardiomiopatias Diabéticas/prevenção & controle , Glucose/metabolismo , Humanos , Metazolamida/metabolismo , Metazolamida/farmacologia , Metazolamida/uso terapêutico , Camundongos , Camundongos Endogâmicos C57BL , Miócitos Cardíacos/metabolismo , Ratos , beta Catenina/metabolismoRESUMO
OBJECTIVES: Investigate if azilsartan protects against myocardial hypertrophy by upregulating nuclear factor erythroid 2-related factor 2 (Nrf2)-mediated pathways. METHODS: Abdominal aortic constriction (AAC)-induced cardiac hypertrophy in rats was applied. Azilsartan or vehicle was administered daily for 6 weeks in sham or AAC rats. Cardiac morphology and ventricular function were determined. Azilsartan effects upon neonatal rat cardiomyocyte (NRCM) hypertrophy and molecular mechanisms were studied in angiotensin (Ang) II-stimulated NRCMs in vitro. Nrf2-small interfering RNA (siRNA) was used to knockdown Nrf2 expression. Messenger RNA (mRNA)/protein expression of Kelch-like erythroid cell-derived protein (Keap)1 and Nrf2 and its downstream antioxidant enzymes was determined by real-time reverse transcription-quantitative polymerase chain reaction and western blotting, respectively. KEY FINDINGS: Azilsartan treatment ameliorated cardiac hypertrophy/fibrosis significantly in AAC rats. Azilsartan increased expression of Nrf2 protein but decreased expression of Keap1 protein. Upregulation of protein expression of Nrf2's downstream antioxidant enzymes by azilsartan treatment was observed. Azilsartan inhibited Ang II-induced NRCM hypertrophy significantly and similar effects on the Keap1-Nrf2 pathway were observed in vivo. Nrf2 knockdown markedly counteracted the beneficial effects of azilsartan on NRCM hypertrophy and the Keap1-Nrf2 pathway. CONCLUSIONS: Azilsartan restrained pressure overload-induced cardiac remodelling by activating the Keap1-Nrf2 pathway and increasing expression of downstream antioxidant enzymes to alleviate oxidative stress.
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Antagonistas de Receptores de Angiotensina/farmacologia , Benzimidazóis/farmacologia , Cardiomegalia/metabolismo , Proteína 1 Associada a ECH Semelhante a Kelch/metabolismo , Miocárdio/metabolismo , Fator 2 Relacionado a NF-E2/metabolismo , Oxidiazóis/farmacologia , Estresse Oxidativo/efeitos dos fármacos , Angiotensina II/metabolismo , Animais , Antioxidantes/metabolismo , Antioxidantes/farmacologia , Cardiomegalia/tratamento farmacológico , Feminino , Ventrículos do Coração/efeitos dos fármacos , Masculino , Miócitos Cardíacos/efeitos dos fármacos , RNA Mensageiro/metabolismo , Ratos Sprague-Dawley , Transdução de Sinais , Regulação para CimaRESUMO
The Hippo pathway undertakes a pivotal role in organ size control and the process of physiology and pathology in tissue. Its downstream effectors YAP1 and TAZ receive upstream stimuli and exert transcription activity to produce biological output. Studies have demonstrated that the Hippo pathway contributes to maintenance of cardiac homeostasis and occurrence of cardiac disease. And these cardiac biological events are affected by crosstalk among Hippo-YAP1/TAZ, Wnt/ß-catenin, Bone morphogenetic protein (BMP) and G-protein-coupled receptor (GPCR) signaling, which provides new insights into the Hippo pathway in heart. This review delineates the interaction among Hippo, Wnt, BMP and GPCR pathways and discusses the effects of these pathways in cardiac biology.
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Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Regulação da Expressão Gênica/fisiologia , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Miocárdio/metabolismo , Proteínas Serina-Treonina Quinases/metabolismo , Proteínas Adaptadoras de Transdução de Sinal/genética , Animais , Humanos , Peptídeos e Proteínas de Sinalização Intracelular/genética , Proteínas Serina-Treonina Quinases/genética , Transdução de SinaisRESUMO
BACKGROUND: Carvacrol is a food additive with various bioactivities, including reducing the blood glucose level as well as improvement of heart function, in diabetic mice. We explored the antihyperglycemic effect of carvacrol and its effect on the key hepatic enzymes accounting for glucose metabolism. METHODS: A streptozotocin (STZ)-induced diabetes-mellitus model in mice was used. Mice were divided randomly into a control group, diabetic group, low dose carvacrol-treated diabetic group (10 mg/kg body weight [BW]), and high dose carvacrol-treated diabetic group (20 mg/kg BW). Carvacrol was injected intraperitoneally (i.p.) in each carvacrol-treated group daily for 4 weeks and 6 weeks, respectively. The level of random plasma glucose, fasting plasma glucose, and plasma insulin was determined at 4 weeks and 6 weeks after carvacrol administration. The plasma level of total cholesterol (TC), triglycerides (TG), aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP), lactate dehydrogenase (LDH), and the activity of hepatic key enzymes related to glucose metabolism were determined. RESULTS: Carvacrol treatment decreased the levels of random plasma glucose and fasting plasma glucose, significantly in a dose-dependent manner. A significant improvement in glucose tolerance and a significant decrease in the plasma level of TG were observed in carvacrol-treated diabetic mice at a dose of 20 mg/kg BW compared with that in vehicle-treated diabetic mice. There was no significant difference in the plasma level of TC and insulin between vehicle-treated diabetic mice and carvacrol-treated diabetic mice. Carvacrol treatment at a dose of 20 mg/kg BW significantly reduced the plasma level of LDH but not AST, ALT, or ALP, compared with that in the vehicle-treated diabetic group. The activity of hexokinase (HK), 6-phosphofructokinase (PFK), and citrate synthetase (CS) was increased by carvacrol treatment in diabetic mice. CONCLUSIONS: Carvacrol exerted an anti-hyperglycemic effect in STZ-induced diabetic mice. This was achieved through regulating glucose metabolism by increasing the activity of the hepatic enzymes HK, PFK, and CS.
Assuntos
Glicemia/metabolismo , Cimenos/farmacologia , Diabetes Mellitus Experimental/tratamento farmacológico , Hipoglicemiantes/farmacologia , Animais , Biomarcadores/sangue , Relação Dose-Resposta a Droga , Insulina/sangue , Camundongos , Camundongos Endogâmicos C57BL , Distribuição Aleatória , EstreptozocinaRESUMO
Because of the rapid increase in bacterial resistance, there is an urgent need for developing new antimicrobial agents to combat multidrug-resistant pathogens. In this study, we designed and synthesized a series of kaempferol derivatives as antimicrobial agents biomimicking the structural properties and biological functions of host defense peptides. After fine-tuning of hydrophobic and cationic hydrophilic moieties linked to the flavone scaffold of kaempferol, we obtained a lead compound (52) that displayed high membrane selectivity (>128), poor hemolytic activity, low cytotoxicity to mammalian cells, and excellent activity against Gram-positive bacteria (minimum inhibitory concentrations = 1.56 µg/mL), including methicillin-resistant Staphylococcus aureus. Compound 52 can kill bacteria quickly by destroying the bacterial membranes and avoid developing bacterial resistance. Moreover, compound 52 exhibited potent in vivo antibacterial activity against S. aureus in a murine corneal infection model. These results indicated that compound 52 had the therapeutic potential as a novel membrane-active antimicrobial to combat Gram-positive bacterial infections.
Assuntos
Anti-Infecciosos/farmacologia , Bactérias Gram-Positivas/efeitos dos fármacos , Quempferóis/química , Animais , Anti-Infecciosos/síntese química , Anti-Infecciosos/uso terapêutico , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Doenças da Córnea/tratamento farmacológico , Doenças da Córnea/microbiologia , Modelos Animais de Doenças , Desenho de Fármacos , Farmacorresistência Bacteriana/efeitos dos fármacos , Bactérias Gram-Positivas/isolamento & purificação , Infecções por Bactérias Gram-Positivas/tratamento farmacológico , Infecções por Bactérias Gram-Positivas/microbiologia , Hemólise/efeitos dos fármacos , Humanos , Quempferóis/farmacologia , Quempferóis/uso terapêutico , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Camundongos , Testes de Sensibilidade Microbiana , Relação Estrutura-AtividadeRESUMO
Bacterial biofilms do serious harm to the diabetic foot ulcer (DFU) because they play a crucial role in infection invasion and spread. Staphylococcus aureus, the predominant Gram-positive bacteria in diabetic foot infection (DFI), is often associated with colonization and biofilm formation. Through biofilm formation tests in vitro, we observed that S. aureus bacteria isolated from DFU wounds were more prone to form biofilms than those from non-diabetic patients, while there was no difference in blood sugar between the biofilm (+) diabetics (DB+) and biofilm (-) diabetics (DB-). Furthermore, we found that advanced glycation end products (AGEs) promoted the biofilm formation of S. aureus in clinical isolates and laboratory strains in vitro, including a methicillin-resistant strain. Analysis of biofilm components demonstrated that the biofilms formed mainly by increasing extracellular DNA (eDNA) release; remarkably, the S. aureus global regulator sigB was upregulated, and its downstream factor lrgA was downregulated after AGE treatments. Mechanism studies using a sigB-deleted mutant (Newman-ΔsigB) confirmed that AGEs decreased expression of lrgA via induction of sigB, which is responsible for eDNA release and is a required component for S. aureus biofilm development. In conclusion, the present study suggests that AGEs promote S. aureus biofilm formation via an eDNA-dependent pathway by regulating sigB. The data generated by this study will provide experimental proof and theoretical support to improve DFU infection healing.