RESUMEN
Millions of people worldwide are exposed to unacceptable levels of arsenic, a proven human carcinogen, in drinking water. In animal models, arsenic and selenium are mutually protective through formation and biliary excretion of seleno-bis (S-glutathionyl) arsinium ion [(GS)2AsSe]-. Selenium-deficient humans living in arsenic-endemic regions are at increased risk of arsenic-induced diseases, and may benefit from selenium supplementation. The influence of selenium on human arsenic hepatobiliary transport has not been studied using optimal human models. HepaRG cells, a surrogate for primary human hepatocytes, were used to investigate selenium (selenite, selenide, selenomethionine, and methylselenocysteine) effects on arsenic hepatobiliary transport. Arsenite + selenite and arsenite + selenide at different molar ratios revealed mutual toxicity antagonism, with the latter being higher. Significant levels of arsenic biliary excretion were detected with a biliary excretion index (BEI) of 14 ± 8%, which was stimulated to 32 ± 7% by selenide. Consistent with the formation and biliary efflux of [(GS)2AsSe]-, arsenite increased the BEI of selenide from 0% to 24 ± 5%. Arsenic biliary excretion was lost in the presence of selenite, selenomethionine, and methylselenocysteine. Sinusoidal export of arsenic was stimulated â¼1.6-fold by methylselenocysteine, but unchanged by other selenium forms. Arsenic canalicular and sinusoidal transport (±selenide) was temperature- and GSH-dependent and inhibited by MK571. Knockdown experiments revealed that multidrug resistance protein 2 (MRP2/ABCC2) accounted for all detectable biliary efflux of arsenic (±selenide). Overall, the chemical form of selenium and human MRP2 strongly influenced arsenic hepatobiliary transport, information critical for human selenium supplementation in arsenic-endemic regions.
Asunto(s)
Arsénico/metabolismo , Hepatocitos/efectos de los fármacos , Hepatocitos/metabolismo , Proteína 2 Asociada a Resistencia a Múltiples Medicamentos/metabolismo , Compuestos de Selenio/farmacología , Línea Celular , Supervivencia Celular/efectos de los fármacos , Regulación de la Expresión Génica/efectos de los fármacos , Técnicas de Silenciamiento del Gen , Humanos , Antagonistas de Leucotrieno/farmacología , Metiltransferasas/genética , Metiltransferasas/metabolismo , Proteína 2 Asociada a Resistencia a Múltiples Medicamentos/genética , Proteínas Asociadas a Resistencia a Múltiples Medicamentos/genética , Proteínas Asociadas a Resistencia a Múltiples Medicamentos/metabolismo , Propionatos/farmacología , Quinolinas/farmacología , Temperatura , Contaminantes Químicos del Agua/metabolismoRESUMEN
Chinese herbal medicine is widely used because it has a good safety profile and few side effects. However, the risk of adverse drug reactions caused by herb-drug interactions (HDIs) is often overlooked. Therefore, the task of identifying possible HDIs and elucidating their mechanisms is of great significance for the prevention and treatment of HDI-related adverse reactions. Since extract from Dioscorea bulbifera L. rhizomes (DB) can cause various degrees of liver damage, it is speculated that HDIs may occur between DB extract and chemicals metabolized or excreted by the liver. Our study revealed that the cardiotoxicity of pirarubicin (THP) was increased by co-administration of DB, and the expression of P-glycoprotein (P-gp) and multidrug resistance-associated protein 2 (Mrp2) in the liver was inhibited by DB extract, which led to the accumulation of THP in heart tissue. In conclusion, there are risks of the co-administration of DB extract and THP. The mechanism of HDIs can be better revealed by targeting the efflux transporters.