Environmentally relevant concentrations of 6-PPDQ disrupts vitamin D3 adsorption and receptor function in Caenorhabditis elegans

Abstract

As derivative of antioxidant of N-(1,3-dimethylbutyl)-N’-phenyl-p-phenylenediamine (6-PPD), 6-PPD quinone (6-PPDQ) is frequently found in environments and body of organisms. Vitamin D3 is an important vitamin needing the adsorption from intestine. In Caenorhabditis elegans, vitamin D3 content was reduced by 0.1-10 μg/L 6-PPDQ. Meanwhile, 6-PPDQ (0.1-10 μg/L) decreased expressions of lrp-2, scl-12, scl-13, and ifo-1, and their RNAi decreased vitamin D3 content in 6-PPDQ exposed animals. 6-PPDQ (0.1-10 μg/L) further decreased nhr-8 expression and increased daf-12 expression, and expression of these 2 vitamin D3 receptor genes could be changed by RNAi of lrp-2, scl-12, scl-13, and ifo-1 after 6-PPDQ exposure. The 6-PPDQ toxicity was increased by RNAi of lrp-2, scl-12, scl-13, ifo-1, and nhr-8 and inhibited by daf-12 RNAi. Moreover, after 6-PPDQ exposure, SOD-3 and HSP-6 expressions were decreased by nhr-8 RNAi and increased by daf-12 RNAi. Therefore, 6-PPDQ potentially caused damage on adsorption of vitamin D3 and function of its receptors, and these effects were related to toxicity induction of 6-PPDQ.