TLR4/NLRP3 Gene Single Nucleotide Polymorphisms And Environmental Risks Interaction Effect On Blood Pressure In Adolescents

Essential hypertension(EH)is a well-recognized risk factor for cardiovascular diseases(CVDs)and chronic kidney disease worldwide.However,the high prevalence,disabling consequences,and relatively low control rate still form severe challenges.The pathogenesis of EH is affected by a variety of factors,but the exact mechanisms and the etiology remain unclear.Immune and inflammation have become a focus of research in the past years,with the hope that they’ll be a novel and promising therapeutic target.As a major branch of the body’s immune defense,the innate immune system serves as the first line of defense against infection.As an important pattern recognition receptor in innate immunity,the expression of TLR4 and NLRP3 is very important for the activation of pro-inflammatory immune responses and have attracted attention for its involvement in hypertension.However,the exact mechanisms responsible for the association remain to be fully defined,especially the studies for adolescent populations are more limited.In recent years,epidemiological studies have reported that the incidence of cardiovascular metabolic disease is elevated among children and adolescents.In the light of that target organ damage induced by hypertension is reversible in the early stage,and it is proposed that adolescence will be presented as an ideal intervention target for CVDs in the near future.In this context,we investigate the hypertension in the early life with a vision to improve the outcomes of patients with critical cardiovascular.Chapter1 Epidemiological characteristics of hypertension and cardiovascular risk factors in adolescents:a cross-sectional study Objective To investigate the prevalence of hypertension and unfavorable metabolic factors such as obesity,dyslipidemia,and HUA;and explore the prediction role of uric acid on hypertension in adolescents and provide some practical basis for the ideal time of urate lowering therapy.Methods In this study,a cross sectional survey method was used.The subjects were high school freshmen participating in a medical examination for enrollment in a large-scale school in Nanning,Guangxi,Southwest China.The project consisted of three stages,namely,questionnaire survey,physical examination,and blood sample collection.Questionnaires were sent home and filled out by the students with their parents’ help,and general information was collected.The anthropometric measurements were performed by trained medical staff according to standard protocols.The Lipids and uric acid in non-fasting blood samples collected by venipuncture were measured.To detect the nonlinear relationships between serum uric acid and blood pressure using smooth curve fitting analysis.A two-stage linear regression was performed to estimate the threshold and saturation effect after adjusted for the same covariates.Results Our sample was comprised 1288 adolescents aged 15-19 years old.The detection rates were 14.1%,6.7%,and 14.1% in overweight,obesity,and hypertension,respectively.In addition,there is a high prevalence of dyslipidemia and HUA in patients who received blood sample tested,especially for hypertriglyceridemia and hypo-HDL-C(15.9% and 23.8%).The detection rate of one abnormal component was 32.3%,and more than two abnormal components was 36.1%.We observed the nonlinear relationship between serum uric acid and DBP,and DBP increased significantly with serum uric acid levels above 10.43 and 10.99mg/ d L in men,overweight and obese.Conclusions The prevalence of cardiovascular metabolic abnormalities is high in adolescents,and these unfavorable factors occur in cluster.In the clinical settings,male with overweight and obese should be early given pharmacologic interventions once serum uric acid levels above 10.43 and 10.99 mg/d L.Chapter2 TLR4/NLRP3 gene single nucleotide polymorphisms and environmental risks interaction effect on blood pressure in adolescents Objective The study was undertaken to detect the association of two single nucleotide polymorphisms(SNPs)in the TLR4/NLRP3 gene(rs1927914 G>A and rs10754558 G>C)and hypertension in adolescents.Traditional risk factors for essential hypertension such as obesity,dyslipidemia and HUA are considered to be environmental factors,we further explored gene-environment interaction effect on hypertension in adolescents.Methods The subjects were 553 adolescents who blood biochemical test and genotype data were available in the epidemiological study.Genotyping of TLR4rs1927914 was performed by KASP method,and genotyping of NLRP3rs10754558 was performed by Sanger sequencing.We validated our genotyping results by a random sample of 5% repeated sequencing.We tested the effect modification by rs1927914 and rs10754558 allelic risk,and multivariate linear regression was performed to estimate the interaction effect through Likelihood-ratio tests.Results Genetic association studies have suggested that rs10754558 was associated with DBP under additive and recessive models(β=2.105,P=0.026 and β=0.938,P=0.045).However,rs1927914 showed no association with blood pressure under three genetic models(P>0.05).The impact of BMI on DBP was influenced by interaction with rs1927914 genotype(P interaction=0.013): DBP significantly increased as BMI levels in subjects with GG(β=1.016,P=0.001),compared to AA and GA(β=0.168,P=0.273;β=0.139,P=0.403);Similarly,the impact of LDL-C on DBP was influenced by interaction with rs1927914genotype(P interaction=0.033).The impact of HDL-C on SBP and DBP was influenced by interaction with rs10754558 genotype(P interaction=0.043 and0.002),the same as the impact of TC on DBP(P=0.011).When analyzed as a dichotomous variable,the impact of TG on SBP and DBP was influenced by interaction with rs10754558 genotype(P interaction=0.023).Conclusions NLRP3 rs10754558 was associated with hypertension in adolescents.TLR4/NLRP3 single nucleotide polymorphisms and traditional risk factor such as obesity and dyslipidemia,as gene-environment interaction effect influenced blood pressure in adolescents.Chapter3 The role of TLR4/NLRP3 gene pathway in hypertension based on expression profile database(GEO/e QTL)and SNP bioinformatics tools Objective The aim of this study is to investigate the expression of TLR4/NLRP3 pathway gene via public databases,and explore their potential connection with hypertension phenotype.With the expression quantitative trait loci(e QTL)data and SNP Bioinformatics tools via public database,we also evaluate the relationship between gene expression levels and genotypes at a specific tissue,and the possible mechanisms through which functional SNP regulate gene expression.Methods We downloaded datasets from the Gene Expression Omnibus(GEO)and the expression profiles of TLR4/NLRP3 and their downstream molecules were collected and analyzed between case and control group.Gene Tissue Expression(GTEx)data on matched genotype and expression data were also collected in multiple tissues including heart,blood vessels,kidneys,adrenal gland,and peripheral blood.Then,the genotype-expression association studies at a specific tissue or organ were performed.We explore the possible mechanisms of functional SNPs located in non-coding regions are often linked to regulate gene expression and influence complex traits via SNP prediction bioinformatics tools.Results In GSE74144,My D88 m RNA levels were significantly elevated among individuals with left ventricular hypertrophy compared to healthy controls and hypertension alone(P= 0.0048、P=0.053).Similarly,ASC m RNA levels were significantly increased among individuals with left ventricular hypertrophy in comparison with hypertensive individuals(P=0.0176).Individuals carrying different genotype in rs1927914 show different TLR4 m RNA levels in the tissue including atrial appendages,left ventricle,and whole blood cell via e QTL analysis.Rs1927914 may affect the gene expression in an allele-specific manner by modifying the sequence polymorphisms of the transcription factor;rs10754558 may affect the gene expression by modifying the sequence polymorphisms of target sites for mi RNA.Conclusions TLR4/NLPR3 gene pathway may be implicated in the pathogenesis of hypertension,especially for left ventricular hypertrophy.Individuals with rs1927914 risk allele are likely to be an especially at-risk population.TLR4 gene rs1927914 and NLRP3 rs10754558 may affect the gene expression in an allele-specific manner by modifying the sequence polymorphisms of the transcription factor or target sites for mi RNA.