Molecular Mechanism Underlying The Endothelial Dysfunctional Effects Of Typical Nitrated And Oxygenated Polycyclic Aromatic Hydrocarbons

Nitrated polycyclic aromatic hydrocarbons(NPAHs)and oxygenated polycyclic aromatic hydrocarbons(OPAHs)are widespread in the atmosphere and pose potential health risks.PAHs are considered a risk factor for cardiovascular diseases,which are characterized by early key events involving the disruption of endothelial dysfunction.Endothelial dysfunction is featured by altered nitric oxide(NO)production and increased permeability of endothelial cells.Herein,we investigated the effects of NPAHs/OPAHs(1-NNAP,9-NANT,9,10-AQ,and 9-FLU)and their parent PAHs(NAP,ANT,and FLU)on NO production of human umbilical vein endothelial cells(HUVECs)by interfering with endothelial nitric oxide synthase(e NOS)in terms of molecular interaction,enzymatic activity,m RNA and protein expression,as well as revealed the permeability changes of HUVECs with regard to the intercellular junction protein expression and distribution.This study figured out the effects of NPAHs,OPAHs and PAHs on endothelial function,providing scientific data support for comprehensive assessment for PAH-related cardiovascular risk assessment.The main research results and conclusions are as follows:(1)1-NNAP,9-NANT,9,10-AQ,and 9-FLU(0.01 μM)significantly decreased NO production to 0.689,0.497,0.429,and 0.429-fold of control;NAP,FLU and ANT(0.01 μM)significantly increased NO production to 1.404,1.441 and 1.352-fold of control.NPAHs and OPAHs significantly reduced NOS activity,while PAHs significantly increased NOS activity.The 100 ns molecular dynamics simulations revealed the different binding characteristics of NPAHs,OPAHs or PAHs with eNOS HEME domain,helped to figure out the distinct effects of PAHs and derivatives on NOS activity.The m RNA expression of eNOS and phosphorylated eNOS(Ser1177)were decreased by four NPAHs/OPAHs but increased by three PAHs.It showed that NPAHs,OPAHs and parent PAHs distinctly affected the production of NO in HUVECs by interfering with NOS activity,eNOS mRNA and protein expression.(2)ANT,9-NANT and 9,10-AQ(0.01 μM)significantly induced a 1.264,1.390 and 1.277-fold increase in FITC leakage,and promoted paracellular gap formations revealed by transmission electron microscope,indicating the increase in permeability was related to the destruction of cell junctions.ANT,9-NANT and 9,10-AQ markedly downregulated the m RNA expression of VE-cadherin,ZO-1 and occludin,as well as the protein expression of ZO-1 and occludin,induced the internalization of VEcadherin,suggesting enhanced permeability of HUVECs was attributed to the disturbance of the expression and distribution of intercelluar junction protein.