The Association Of Polycyclic Aromatic Hydrocarbons Exposure With Mosaic Loss Of Chromosome Y Among Coke-oven Workers

Mosaic loss of chromosome Y?mLOY?refers to a portion of cells losing the Y chromosome,while the remaining retains the normal chromosome Y.It was recently considered that loss of Y chromosome in peripheral blood represents a proxy trait for aneuploidy and can be readily estimated from array-based genotyping data or sequencing reads.LOY-status of blood cells is correlated with an increased risk for all-cause mortality as well as non-hematological cancers mortality,and is an appropriate biomarker of male carcinogenesis.Some epidemiological studies also reported that men with higher frequency of leukocyte mLOY had elevated risks of Alzheimer disease,cardiovascular events,and autoimmune diseases.Thus,identifying the risk factors for mLOY is of great clinical significance for the prevention of chronic diseases.It was previously suggested that mLOY was age-related,and males could develop aggravated mLOY as they getting old.However,recent epidemiologic investigations indicated that mLOY could be modified by environmental and genetic factors.Compared with never-smokers and former-smokers,current-smokers showed the highest level of mLOY.Exposure to air particulate matter?10?m?PM10?might exacerbate leukocyte mLOY.Two previous genome-wide association studies?GWAS?had observed several common mLOY-related loci.However,there are not yet investigations about the interative and combine effects of the environmental and genetic factors on mLOY.As the major common genotoxic components to cigarette smoke and particulate matter,polycyclic aromatic hydrocarbons?PAHs?exposure had been widely reported to be associated with increased risks of cancers and cardiovascular diseases?CVD?.Coke-oven plant can produce plenty of coke oven emissions?COEs?,and the mainly components are PAHs.The coke-oven workers are a typical population with high level of PAHs exposure.Once absorbed,the metabolic process of PAHs could produce many reactive oxygen species?ROS?,and the PAHs can also directly bind with the DNA to form PAHs-DNA adducts,which could lead to oxidative stress and chromosome damage.As a result,we hypothesized that exposure to PAHs may also cause mLOY,and then take parts in the development of above diseases.To systematically investigate the dose-response relationships between PAHs exposure and mLOY,we performed a cross-sectional study including 1005 male workers from a coke-oven plant.The urinary concentrations of 10 PAH metabolites and plasma concentrations of anti-7,8,-dihydrodiol-9,10-epoxide benzo[a]pyrene-Albumin?BPDE-Alb?adducts were determined for each participant,in order to measure their internal PAH exposure levels.We carried out the genome-wide genotyping of these subjects by using the SNP genotyping array,estimated their levels of mLOY based on the single nucleotide polymorphism?SNP?array data,and extracted the genotypes of mLOY-related SNPs according to the GWAS findings.Additionally,we evaluated the interative and combined effects of age,tobacco smoking,and SNPs with PAHs on mLOY among these male participants.Objectives:We aimed to investigate whether exposure to PAHs were associated with accelerated mLOY,and further explore the interactive and combined effects of age,tobacco smoking,and SNPs with PAHs on mLOY among these male participants.Methods:A total of 1005 male coke-oven workers were included in this study.We obtained basic information on their demographic characteristics,health status,lifestyles,and occupational history by training researchers to interview face-to-face based on a standardized questionnaire.The anthropometric data,including weight and height,were obtained by direct measurement.We define the score for body mass index?BMI?as weight divided by squared height?kg/m²?.Each participant donated fasting blood and urine samples.The urinary levels of 10 PAH metabolites were detected by using gas chromatography-mass spectrometer?GC-MS?,regarding the sum of 10 metabolites as?OH-PAHs,and the plasma levels of BPDE-Alb adducts were measured by enzyme linked immunosorbent assay?ELISA?methods.We conducted the SNP microarray genotyping experiments on each subject,and estimated mLOY with standard method using the median Log-R Ratios?mLRR,observed intensity/expected intensity?of 1480probes in the male-specific region of chromosome Y?ChrY:2655180-59034049,hg19/GRCH37?.The lower level of mLRR-Y indicated a higher level of mLOY.The selection of mLOY-related SNPs was based on the reported of Wright et al.'s study,which recently conducted a GWAS in 85,542 men with European ancestry and identified 19 genomic regions associated with mLOY at a genome-wide significance level(P<5×10^-8).We selected 14 SNPs,including rs2736609,rs4754301,rs9805742,rs10151519,rs1122138,rs12448368,rs11082396,rs13088318,rs6802910,rs56084922,rs13191948,rs381500,rs4721217,and rs6468341 with the same methods used in Qin Na et's study.The dose-response relationship of PAHs exposure biomarkers with mLRR-Y were estimated by using multiple linear regression models,with adjustment for age,BMI,pack-years,alcohol drinking status,exercise,and experimental batch.Since age and cigarette smoking had been reported to be mLOY-related,we further explored the interactive and joint effects of age,smoking status,and SNPs with PAHs exposure on mLOY.Results:We found that age and smoking pack-years both showed significant inverse associations with peripheral leukocyte mLRR-Y[??95%CI?=-0.0004?-0.0007,-0.0001?and-0.0002?-0.0004,-0.000?,P=0.020 and 0.042,respectively].Each PAH exposure biomarker was separately included in the regression models to estimate their associations with mLRR-Y.We found that,among all participants,the levels of urinary 1-hydroxynaphthalene?1-OHNa?,1-hydroxyphenanthrene?1-OHPh?,2-OHPh,1-hydroxypyrene?1-OHP?,the sum of 10 PAHs metabolites??OH-PAHs?,and plasma BPDE-Alb adducts were significantly associated with lower levels of mLRR-Y,with 10-fold increase in level of each biomarker generate a 0.011,0.008,0.007,0.010,0.013,and0.015 decrease in mLRR-Y?all P value<0.05?.But we failed to find the significant associations of 2-OHNa,2-hydroxyphenanthrene?2-OHFlu?,9-OHFlu,3-OHPh,4-OHPh,and 9-OHPh with mLRR-Y.The sensitivity analyses after excluding 79participants with self-report diseases of cardiovascular disease,benign tumor or diabetes mellitus did not materially change the above associations.We further categorized all subjects according to the quartile levels of each PAH exposure biomarker,and found that males within the highest quartile subgroup?Q4?of urinary 1-OHNa,2-OHFlu,1-OHPh,2-OHPh,9-OHPh and?OH-PAHs had a separate0.011,0.010,0.011,0.010,0.010,and 0.012 reduction in mLRR-Y,when compared to those within the first quartile subgroup?Q1?in each of these biomarkers?all P<0.05?.The significantly or marginally increasing trends in mLRR-Y were found across the quartile subgroups of urinary 1-OHNa,2-OHFlu,1-OHPh,2-OHPh,4-OHPh,9-OHPh,1-OHP,?OH-PAHs(all P_trend<0.05),and plasma BPDE-Alb adducts(P_trend=0.051),with the exception of 2-OHNa,9-OHFlu,and 3-OHPh(P_trend=0.122,0.227,and 0.076,respectively).We also conducted the stratification analyses by age??45 and>45 years-old?and smoking status?never smokers and ever smokers?.Among the young participants with aged?45 years-old,there were significant inverse associations of 1-OHNa and 1-OHPh with mLRR-Y[??95%CI?:-0.012?-0.021,-0.002?and-0.010?-0.018,-0.002?,P=0.019and 0.014,respectively].Among the elder participants with aged>45 years,the significant dose-response relationships were found between 2-OHFlu,1-OHP,?OH-PAHs and mLRR-Y[??95%CI?:-0.014?-0.026,-0.003?,-0.018?-0.030,-0.006?,and-0.020?-0.036,-0.005?,P=0.011,0.004,and 0.011,respectively].For never smokers,there was none significant association between each PAH exposure biomarker and mLRR-Y?all P>0.05?,while among ever smokers,a 10-fold increae in 1-OHNa,1-OHPh,2-OHPh,1-OHP,and?OH-PAHs level was associated with a separate 0.011,0.010,0.009,0.013,and 0.015 decrease in mLRR-Y?all P<0.05?.However,no significant interaction effects on mLRR-Y were found for age and smoking status with each PAH exposure biomarker.When analyzing the associations between mLOY-related SNPs with mLRR-Y among our study participants,we used the multiple linear regression models,with adjustment for age,BMI,pack-years,drinking,exercise,urinary?OH-PAHs,plasma BPDE-Alb adducts,and experimental batch.We verified the significant association of rs1122138 in TCL1A gene with mLOY,with one increase in minor allele dosage?A?resulting in 0.007 increase of mLRR-Y?P=0.037?,but we did not find the significant associations for the other 13 SNPs.We further selected 57 SNPs within the region of upstream and downstream 10kb of TCL1A gene based on the SNP microassay data,and identified another 9 SNPs were also significantly associated with increased mLRR-Y value.These 9 SNPs were all in a highly linkage disequilibrium with rs1122138.After subgrouping the participants according to rs1122138 genotypes?CA+AA or CC genotype?,we observed that among the rs1122138CC carriers,a 10-fold increase in urinary 1-OHNa,1-OHPh,1-OHP,?OH-PAHs,and plasma BPDE-Alb adducts were separately associated with a 0.011,0.010,0.009,0.012,and 0.018 decrease in mLRR-Y?all P<0.05?.But these associations were not shown among the rs1122138CA+AA carriers.In addition,the urinay 2-OHFlu showed inverse association with mLRR-Y among rs1122138CA+AA carriers[??95%CI?:-0.012?-0.022,-0.002?],but not among rs1122138CA+AA carriers.There were no significant interactions between each PAH exposure biomarker and rs1122138 on mLRR-Y.We further explored the combined effects of age,smoking status,and SNP rs1122138 with PAHs exposure on elevating mLOY.It was shown that,compared to young workers?aged?45?with low PAHs exposure?urinary?OH-PAHs<19.39?g/mmol creatinine?,the elder workers?aged>45?with high PAHs exposure??19.39?g/mmol creatinine?had lower level of blood mLRR-Y[??95%CI?=-0.017?-0.027,-0.007?,P=0.001].Compared to never smokers with low PAH exposure,the ever smokers with high PAH exposure had a higher degree of mLOY,with a 0.008 decrease in mLRR-Y[95%CI:-0.017 to 0.001,P=0.073].The high PAHs exposed rs1122138 CC carriers showed the lowest level of blood mLRR-Y among the four subgroups,who had a 0.014?95%CI:-0.023 to-0.005,P=0.004?decreased mLRR-Y than the low PAHs exposed workers carrying rs1122138 CA or AA genotype.Compared with those exposed to none risk factor?>45years,ever smokers,rs1122138CC genotype and high PAHs exposure level?,those who exposed to three or four risk factors both showed a lower mLRR-Y[??95%CI?=-0.019?-0.034,-0.003?,P=0.020 and-0.027?-0.045,-0.009?,P=0.003].Conclusion:Our study found that males with elevated exposure to PAHs had a dose dependent increased level of blood mLOY.Our study verified the effects of age,smoking,and TCL1A gene variations on male mLOY,and illustrated the combine effects of PAHs exposure with age,smoking and TCL1A variation on mLOY.But the underlying mechanisms behind these observations need further investigations.These results provided new epidemiological evidence for the risk factors of mLOY and suggested potential preventive clues for mLOY-related chronic diseases.