RESUMEN
Bacterial infection is a major threat to the health and life of humans due to the development of drug resistance, which is related to biofilm formation. Nitric oxide (NO) has emerged as an important factor in regulating biofilm formation. In order to harness the potential benefits of NO and develop effective antibacterial agents, we designed and synthesized a new class of NO hybrids in which the active scaffold benzothienoazepine was tagged with a nitroso group and further conjugated with quaternary ammoniums or phosphoniums. The temporal release of NO from these hybrids can be achieved by photoactivation. Interestingly, the NO release follows a pseudo-zero-order kinetics, which is easily determined by measuring the fluorescent benzothienoazepine or NO. Compared to the positive control ciprofloxacin, the NO hybrid with triphenyl phosphonium (TPP) exhibited more effective activity against S. aureus biofilm in darkness. Irradiation of the NO hybrid led to higher inhibition against S. aureus biofilm compared to the parental NO hybrid in darkness or the corresponding NO-released product, indicating the combined effect of NO and the NO-released product. Therefore, this new class of NO hybrids includes very promising antimicrobial agents and this work provides a new way for the design of highly effective antimicrobial agents.
Asunto(s)
Antibacterianos/farmacología , Azepinas/farmacología , Biopelículas/efectos de los fármacos , Óxido Nítrico/metabolismo , Staphylococcus aureus/efectos de los fármacos , Antibacterianos/síntesis química , Antibacterianos/química , Azepinas/síntesis química , Azepinas/química , Relación Dosis-Respuesta a Droga , Diseño de Fármacos , Cinética , Pruebas de Sensibilidad Microbiana , Estructura Molecular , Procesos FotoquímicosRESUMEN
Endemic fluorosis is a serious problem in public health, affecting thousands of people. Abnormal proliferation and activation of osteoblasts in skeletal fluorosis lesions play a leading role and osteoblast proliferation is finely regulated by the cell cycle. There are a few reports on fluoride-induced DNA methylation. However, the role of DNA methylation of the cyclin/cyclin-dependent kinase (CDK)/cyclin-dependent kinase inhibitor (CKI) regulatory network in skeletal fluorosis has not been investigated. We used a population study and in vitro experiment to explore the relationship between the pathogenesis of skeletal fluorosis and methylation of Cyclin d1/CDK4/p21. The results showed a positive relationship between fluoride exposure and expression of Cyclin d1/CDK4, and a negative relationship between fluoride exposure and expression of P21. Hypermethylation of p21 was found in the fluoride-exposed population, and low expression of p21 attributed to promoter hypermethylation was confirmed in vitro. However, no changes in methylation levels of Cyclin d1 and CDK4 genes were observed in the population exposed to fluoride and NaF-treated osteoblasts. These results show that methylation of p21 gene has a significant impact on the proliferation of osteoblasts during the development of skeletal fluorosis. The present study was a first attempt to link the methylation of the Cyclin d1/CDK4/p21 regulatory network with osteoblast proliferation in skeletal fluorosis.
Asunto(s)
Quinasa 4 Dependiente de la Ciclina/genética , Metilación de ADN/genética , Intoxicación por Flúor/genética , Fluoruros/efectos adversos , Adulto , Ciclo Celular/efectos de los fármacos , Ciclo Celular/genética , Proliferación Celular/efectos de los fármacos , Proliferación Celular/genética , Preescolar , Inhibidor p21 de las Quinasas Dependientes de la Ciclina/genética , Metilación de ADN/efectos de los fármacos , Femenino , Humanos , Masculino , Osteoblastos/efectos de los fármacos , Adulto JovenRESUMEN
Triarylmethanol adopts a propeller-shaped conformation with either right-handed (P) or left-handed (M) configuration. Herein, new triarylmethanols with two chiral centers were obtained via introduction of two cis-hydroxyl groups on the side chains, affording four stereoisomers. These four stereoisomers were easily separated by silica gel column chromatography into two pairs of propeller-shaped enantiomers, as shown by NMR and X-ray crystallographic studies. High-performance liquid chromatography (HPLC) studies showed that the configurations of the hydroxyl-bearing triarylmethanols are much more stable than those of the bulky tert-butyldimethylsilyl-protected precursors, inconsistent with the general strategy in which the steric repulsion is largely responsible for the configurational stability. Similarly, two hydroxyl-bearing tetrathiatriarylmethyl (TAM) radicals also exhibit excellent configurational stability and are thus separable by CS-HPLC into four stereoisomers. Interestingly, both helical chirality from triaryl group (M or P) and central chirality (R and S) on the side chain have little effect on their electron paramagnetic resonance properties. Our present study provides a new strategy to construct configurationally stable triaryl compounds and demonstrates that the side chain on TAM radicals is a new site for their structural modifications.
RESUMEN
Chronic exposure to fluoride continues to be a public health problem worldwide, affecting thousands of people. Fluoride can cause abnormal proliferation and activation of osteoblast and osteoclast, leading to skeletal fluorosis that can cause pain and harm to joints and bones and even lead to permanent disability. Nevertheless, there is no recognized mechanism to explain the bone lesions of fluorosis. In this work, we performed a population study and in vitro experiments to investigate the pathogenic mechanism of skeletal fluorosis in relation to methylation of the promoter of p16. The protein coded by the p16 gene inhibits cdk (cyclin-dependent kinase) 4/cdk6-mediated phosphorylation4 of retinoblastoma gene product and induces cell cycle arrest. The results showed that hypermethylation of p16 and reduced gene expression was evident in peripheral blood mononuclear cells of patients with fluorosis and correlated with the level of fluoride exposure. Studies with cell cultures of osteoblasts revealed in response to sodium fluoride (NaF) treatment, there was an induction of p16 hypermethylation and decreased expression, leading to increased cell proliferation, a longer S-phase of the cell cycle, and development of skeletal fluorosis. Further, the methylation inhibitor, 5-aza-2-deoxycytidine, reversed the p16 hypermethylation and expression in response to NaF. These results reveal a regulatory role of p16 gene methylation on osteoblasts activation during the development of skeletal fluorosis.
Asunto(s)
Proliferación Celular/efectos de los fármacos , Inhibidor p16 de la Quinasa Dependiente de Ciclina/genética , Metilación de ADN , Osteoblastos/efectos de los fármacos , Fluoruro de Sodio/farmacología , Adulto , Enfermedades Óseas/sangre , Enfermedades Óseas/inducido químicamente , Enfermedades Óseas/genética , Enfermedades Óseas/orina , División Celular/efectos de los fármacos , División Celular/genética , Proliferación Celular/genética , Células Cultivadas , Preescolar , Inhibidor p16 de la Quinasa Dependiente de Ciclina/metabolismo , Metilación de ADN/efectos de los fármacos , Metilación de ADN/genética , Femenino , Fluoruros , Expresión Génica/efectos de los fármacos , Humanos , Leucocitos Mononucleares/efectos de los fármacos , Leucocitos Mononucleares/metabolismo , Masculino , Osteoblastos/fisiología , Regiones Promotoras Genéticas/efectos de los fármacos , Fluoruro de Sodio/orina , Adulto JovenRESUMEN
Much attention has been paid to develop optical probes for noninvasive, quantitative, in vivo monitoring of hydrogen peroxide (H2O2) due to its important roles in the initiation and development of numerous diseases. Motivated to meet this need, we herein report the synthesis of a near-infrared (NIR) fluorescent probe (AB1) for H2O2 by modulating intramolecular charge transfer (ICT) process of the dye 9H-1,3-Dichloro-7-hydroxy-9,9-dimethylacridine-2-one (DDAO). The probe AB1 exhibits both a large NIR fluorescence turn-on and a ratiometric response to H2O2 with high sensitivity and specificity. The fluorescence response of AB1 has a good linear relationship with H2O2 over a wide concentration range from 1⯵M to 100⯵M, thus affording a detection limit of 0.42⯵M. Confocal microscopic experiments demonstrated that AB1 could ratiometrically detect exogenous and endogenous H2O2 in living cells. Moreover, owing to the NIR emission of DDAO, the probe was also utilized to image endogenous H2O2 from the peritoneal cavity in a mouse model of lipopolysaccharide-induced acute inflammation, based on the fluorescence turn-on mode. This new probe shows great potential as a reliable chemical tool to study the development and progression of H2O2-associated diseases in living animals.