RESUMEN
4-Hydroxycordoin (1), a natural isopentenyloxychalcone, is a plant secondary metabolite that is relatively rare. Since there are very few reports about the biological activities of 1, its potential benefits for periodontal disease were investigated. A marked and dose-dependent antibacterial activity of 1 was observed against the three major periodontal pathogens, Porphyromonas gingivalis, Fusobacterium nucleatum, and Prevotella intermedia. Moreover, compound 1 showed an antiadhesion effect, since it inhibited attachment of P. gingivalis to oral epithelial cells. Finally, using a macrophage model, the ability of 1 to inhibit the secretion of inflammatory mediators induced by Aggregatibacter actinomycetemcomitans lipopolysaccharide was demonstrated. The anti-inflammatory effect observed was associated with reduced activation of the nuclear factor-κB (NF-κB) p65 and activator protein-1 (AP-1) pathways.
Asunto(s)
Antibacterianos/aislamiento & purificación , Antibacterianos/farmacología , Antiinflamatorios/farmacología , Chalconas/aislamiento & purificación , Chalconas/farmacología , Enfermedades Periodontales/tratamiento farmacológico , Antibacterianos/química , Antiinflamatorios/química , Antiinflamatorios/aislamiento & purificación , Chalconas/química , Dinoprostona/análisis , Dinoprostona/metabolismo , Relación Dosis-Respuesta a Droga , Fabaceae/química , Humanos , Lipopolisacáridos/farmacología , Macrófagos/efectos de los fármacos , Modelos Biológicos , Estructura Molecular , Enfermedades Periodontales/microbiología , Proteína de Replicación C/efectos de los fármacos , Factor de Transcripción ReIA/efectos de los fármacosRESUMEN
In mammalian cells DNA damage activates a checkpoint that halts progression through S phase. To determine the ability of nitrating agents to induce S-phase arrest, mouse C10 cells synchronized in S phase were treated with nitrogen dioxide (NO(2)) or SIN-1, a generator of reactive nitrogen species (RNS). SIN-1 or NO(2) induced S-phase arrest in a dose- and time-dependent manner. As for the positive controls adozelesin and cisplatin, arrest was accompanied by phosphorylation of ATM kinase; dephosphorylation of pRB; decreases in RF-C, cyclin D1, Cdc25A, and Cdc6; and increases in p21. Comet assays indicated that RNS induce minimal DNA damage. Moreover, in a cell-free replication system, nuclei from cells treated with RNS were able to support control levels of DNA synthesis when incubated in cytosolic extracts from untreated cells, whereas nuclei from cells treated with cisplatin were not. Induction of phosphatase activity may represent one mechanism of RNS-induced arrest, for the PP1/PP2A phosphatase inhibitor okadaic acid inhibited dephosphorylation of pRB; prevented decreases in the levels of RF-C, cyclin D1, Cdc6, and Cdc25A; and bypassed arrest by SIN-1 or NO(2), but not cisplatin or adozelesin. Our studies suggest that RNS may induce S-phase arrest through mechanisms that differ from those elicited by classical DNA-damaging agents.
Asunto(s)
Ácido Ocadaico/farmacología , Fosfoproteínas Fosfatasas/antagonistas & inhibidores , Especies de Nitrógeno Reactivo/farmacología , Fase S/efectos de los fármacos , Animales , Proteínas de la Ataxia Telangiectasia Mutada , Ciclo Celular/efectos de los fármacos , Proteínas de Ciclo Celular/efectos de los fármacos , Proteínas de Ciclo Celular/metabolismo , Línea Celular , Células Cultivadas , Cisplatino/farmacología , Ciclina D1/efectos de los fármacos , Ciclina D1/metabolismo , ADN/biosíntesis , ADN/efectos de los fármacos , Daño del ADN/efectos de los fármacos , Proteínas de Unión al ADN/efectos de los fármacos , Proteínas de Unión al ADN/metabolismo , Relación Dosis-Respuesta a Droga , Técnicas In Vitro , Ratones , Molsidomina/análogos & derivados , Molsidomina/farmacología , Dióxido de Nitrógeno/farmacología , Proteínas Nucleares/efectos de los fármacos , Proteínas Nucleares/metabolismo , Fosforilación , Proteínas Serina-Treonina Quinasas/efectos de los fármacos , Proteínas Serina-Treonina Quinasas/metabolismo , Especies de Nitrógeno Reactivo/antagonistas & inhibidores , Especies de Nitrógeno Reactivo/metabolismo , Proteína de Replicación C/efectos de los fármacos , Proteína de Replicación C/metabolismo , Proteína de Retinoblastoma/efectos de los fármacos , Proteína de Retinoblastoma/metabolismo , Factores de Tiempo , Proteínas Supresoras de Tumor/efectos de los fármacos , Proteínas Supresoras de Tumor/metabolismo , Fosfatasas cdc25/efectos de los fármacos , Fosfatasas cdc25/metabolismoRESUMEN
We have previously shown that the regulatory subunit of PKA, RIalpha, functions as a nuclear transport protein for the second subunit of the replication factor C complex, RFC40, and that this transport appears to be crucial for cell cycle progression from G1 to S phase. In this study, we found that N(6)-monobutyryl cAMP significantly up-regulates the expression of RFC40 mRNA by 1.8-fold and its endogenous protein by 2.3-fold with a subsequent increase in the RIalpha-RFC40 complex formation by 3.2-fold. Additionally, the nuclear to cytoplasmic ratio of RFC40 increased by 26% followed by a parallel increase in the percentage of S phase cells by 33%. However, there was reduction in the percentage of G1 cells by 16% and G2/M cells by 43% with a concurrent accumulation of cells in S phase. Interestingly, the higher percentage of S phase cells did not correlate with a parallel increase in DNA replication. Moreover, although cAMP did not affect the expression of the other RFC subunits, there was a significant decrease in the RFC40-37 complex formation by 81.3%, substantiating the decrease in DNA replication rate. Taken together, these findings suggest that cAMP functions as an upstream modulator that regulates the expression and nuclear translocation of RFC40.