Association Between The CMIP And HPR Genes Polymorphisms And Serum Lipid Levels In Two Ethnic Groups Of China And IgA Nephropathy

Part I : ASSOCIATION BETWEEN THE CMIP AND HPR SINGLE NUCLEOTIDE POLYMORPHISMS AND SERUM LIPID LEVELS IN TWO ETHNIC GROUPS OF CHINABackground: Cardiovascular disease is the leading cause of death in most countries in the world,including China.In recent years,the incidence of ischemic cardiovascular diseases based on atherosclerosis is still increasing year by year.Data show that dyslipidemia is one of the important causes of atherosclerosis.It is well-known that serum lipid levels are influenced by environmental factors(such as population characteristics,dietary structure,lifestyle,etc.),genetic factors,and their interactions.Recent human genetic and genome-wide association studies(GWASes)have discovered some new genes loci affecting serum lipid levels.As compared with the traditional lipid-related genes,the relationship between these new genes and blood lipid levels remains to be confirmed,and the mechanism of lipid metabolism is also not well known to humans.Recent studies have found that the CMIP and HPR genes may beclosely related to the level of serum TC,LDL-C and HDL-C.Maonan nationality is one of the 55 ethnic minorities in China,and it is also one of the several isolated ethnic minorities in Guangxi province.Its geographical position,living environment,eating habits,behavior lifestyle,intra-ethnic marriages and genetic background are different from the local Han nationality,which is a better group for studying risk factors for dyslipidemia.In this study,5 newly found lipid-related SNPs in the HPR and CMIP genes were selected for genotyping.The effects of environmental factors,genetic factors and their interactions on the serum lipid levels in the Maonan population were analyzed and compared with those in the Han population.Objective: The present study was conducted to investigate the serum lipid distribution in Maonan and Han nationalities,explore the association of CMIP and HPR SNPs and their haplotypes with serum lipid levels.The influences of environmental factors,genetic factors and their interaction on serum lipid levels were also analyzed.Method: Our study population was selected from the Maonan and local Han population resided in the Huanjiang Maonan Autonomous County in the Northwestern of Guangxi Zhuang Autonomous Region of Southwestern China by using a multistage,stratified and randomized sampling scheme.This study finally included 1263 unrelated subjects of Maonan nationality and 1251 participants of Han nationality.All subjects were rural agricultural workers from the same area.The age structure and sex ratio were matched between the two ethnic groups.Questionnaire and physical examination were performed.Serum TC,TG,HDL-C,LDL-C,Apo A1 and Apo B levels were tested.BMI and Apo A1/Apo B ratio were calculated.Genomic DNA of the samples was isolated from peripheral blood leucocytes according to the phenol-chloroform method.Genotypes of the CMIP rs2925979,CMIP rs16955379,CMIP rs56823429,HPR rs2000999 and HPR rs1065360 SNPs were determined by polymerase chain reaction and restriction fragment length polymorphism(PCR-RFLP),and then the genotypes were verified by direct sequencing of PCR products.The linkage disequilibrium(LD)detection,estimation of D' value or r2 value and haplotype analysis were accomplished using SHEsis online software.Results: There were statistically significant differences in TG,HDL-C,LDL-C and Apo B levels between Maonan and Han ethnic groups(P < 0.05),and higher TG,LDL-C and Apo B levels and lower HDL-C levels were found in Maonan population.The genotypic and allelic frequencies of CMIP rs16955379,CMIP rs2925979,HPR rs1065360 and HPR rs2000999 were significant different between Maonan and Han nationalities(P < 0.05).The genotypic frequencies of the CMIP rs16955379 SNP between males and females in Maonan nationality,CMIP rs2925979 genotypic frequencies between males and females in Han and Maonan nationality,and HPR rs2000999 genotypic frequencies between males and females in Han nationality were significantly different.The allelic frequencies of CMIP rs2925979 were significantly different between males and females in Maonan population(P < 0.05,respectively).Serum HDL-C level of different genotypes in CMIP rs16955379 was significantly different in Han population.Serum TC,TG,LDL-C and APOB levels of different genotypes in CMIP rs2925979 were significant different in Han population,and serum LDL-C level of different genotypes in CMIP rs2925979 was significantly different in Maonan population.Serum TG level of different genotypes in CMIP rs2925979 were significantly different in Han males,while serum TC?LDL-C and Apo B levels of different genotypes in CMIP rs2925979 were significantly different in Han females,.Serum Apo A1 level of different genotypes in HPR rs1065360 was significantly different in Han population,and the Aao B level of different genotypes in HPR rs1065360 was significantly different in Han males(5 SNPs,P < 0.05/5,respectively).Serum lipid levels both in Maonan and Han population were closely associated with age,gender,waist circumference,systolic blood pressure,diastolic blood pressure,glucose,smoking and alcohol consumption(P < 0.05,respectively).There is a Linkage disequilibrium between CMIP rs16955379,CMIP rs2925979,CMIP rs56823429,HPR rs2000999 and HPR rs10653605.The most common haplotype was G-C-A-G-T.The frequencies of G-C-A-G-T,G-T-C-A-T,A-TC-A-T and G-T-A-G-T haplotypes was significantly different between the two ethnic groups(P<0.05).Serum lipid levels were significantly different in the two populations with the four different haplotypes(4 index,P < 0.05/4).The risk of dyslipidemia increased if subjects had some risk factors(Obesity,smoking,alcohol consumption or agedness)with G-C-A-G-T haplotype together in the two ethnic group(P < 0.05).Conclusion: There was a difference in serum lipid levels between Maonan and Han population.Age,gender,waist circumference,blood pressure,glucose,smoking and alcohol consumption were risk factors of dyslipidemia in the two ethnic groups.The genotypic and allelic frequencies of CMIP and HPR gene SNPs were significantly different between the two ethnic groups.There were also differences in the relationship of HPR and CMIP gene polymorphism and serum lipid levels between males and females.It is suggested that HPR and CMIP gene polymorphism and their haplotypes are closely related to lipid level,and the two gene SNPs ang their haplotypes were associated with serum lipid levels had ethnic-and/or genderspecificity.There was a Linkage disequilibrium between the five SNPs loci,which may interact with each other to influence lipid metabolism.Thedifference of serum lipid spectrum between the two ethnic groups could be partly attributable to CMIP and HPR gene SNPs and their haplotypes,and G-CA-G-T was the most common haplotype.Related haplotyoes may be associated with increasing of dyslipidemia.Related haplotypes interacted with environmental factors play an important role in dyslipidemia.Haplotypes are more related with lipid metabolic abnormalities than a single SNP.Environmental factors,genetic factors and their interaction both affected serum lipid levels in Maonan and Han population.Part II:ASSOCIATION OF THE CMIP GENE SINGLE NUCLEOTIDE POLYMORPHISM WITH SERUM LIPIDS LEVEL AND DYSLIPIDEMIA OF Ig A NEPHROPATHYBackground: Ig A nephropathy(Ig AN)is the most common primary glomerular disease in China.About 15~40% of patients eventually develop to the end-stage renal disease,requiring renal replacement therapy and consuming a large amount of medical resources.Ig AN is a complex disease affected by multiple genes and environmental factors.Many studies suggest that genetic factors play an important role in the pathogenesis of Ig AN.The clinical andpathological manifestations of Ig AN are diverse.Dyslipidemia is the main risk factor of atherosclerosis which is the most common cause of cardiovascular disease.The data indicated that patients with Ig AN,regardless of progression to chronic renal failure or end-stage renal disease,have the most common complications and causes of death from cardiovascular disease.The effect of dyslipidemia on cardiovascular complications and renal progression in chronic renal diseases has been confirmed.However,there is very limited research on the genetic background of dyslipidemia susceptibility in Ig AN patients.The CMIP gene was recently found to be closely related to TC,LDL-C and HDL-C levels.The relationship between dyslipidemia of Ig AN and CMIP gene polymorphism has not been reported so far.Objective: The purpose of this study is to detect the effect of CMIP gene single nucleotide polymorphism(CMIPrs2925979 and CMIPrs16955379)on serum lipid levels and dyslipidemia of Ig AN;to analyze the risk factors related to the serum lipid level of Ig AN,and to explore the clinical and pathological indexes associated with CMIP gene SNPs in Ig AN.Method: All the subjects were patients diagnosed with Ig A nephropathy in the First Affiliated Hospital of Guangxi Medical University from August 2010 to December 2017.Questionnaire and physical examination were carried out on543 patients with Ig A nephropathy(281 patients with dyslipidemia and 262 patients without dyslipidemia).TC,TG,HDL-C,LDL-C,Apo A1 and Apo Blevels were tested,calculating BMI and Apo A1/Apo B ratio were conducted.Blood samples were extracted for DNA,PCR amplification,electrophoresis imaging,and then PCR products were sent to direct sequencing to measure genotypes.The clinical and pathological data were compared and analyzed of between dyslipidemia group and without dyslipidemia group.Wecompared the genotypic and allelic frequencies between Ig AN with dyslipidemia group and normal serum lipid group,and divided them into four groups: Ig AN dyslipidemia + carrying the loci allele;Ig AN dyslipidemia + not carrying the loci allele;Ig AN non-dyslipidemia + carrying the loci allele;Ig A non-dyslipidemia + not carrying the loci allele,and the results were compared between different groups.We explored the relationship between CMIP gene SNPs and serum lipid levels and dyslipidemia in Ig AN,and analyzed the risk factors associated with serum lipid levels in Ig AN.Genotype Hardy-Weinberg equilibrium,LD calculation and haplotypes analysis were analyzed using SHEsis software.Result: Of the 543 patients,281 were dyslipidemia(51.7%).Ig AN patients blood lipids group compared with dyslipidemia group,two groups between BMI,TC,TG,LDL,Apo A1,systolic pressure,diastolic pressure,urea(BUN),uric acid(UA),and estimated glomerular filtration rate(e GFR),propagated(albumin),drinking,decline in renal function,high blood pressure,edema,hematuria tubular atrophy and interstitial fibrosis,comparing the difference was statistically significant(P < 0.05).The genotype and allele frequency of CMIPrs16955379 were statistically significant between the two groups.The genotype and allele frequencies of CMIPrs2925979 were not statistically significant between the two groups(P < 0.05).Serum HDL-C level were different in diversity of CMIP rs16955379 genotypes,and serum TG and Apo A1 levels were different in diversity of CMIPrs2925979 genotypes.There were significant different between CMIP rs16955379 C allele carriers and noncarriers in serum TG and Apo A1 level,between CMIP rs2925979 A allele carriers and not carriers in serum TC and TG levels.(2 SNPs,P< 0.05/2,respectively).Comparing clinical and pathological data between different allelescarriers of Ig A nephropathy: serum TG,HDL,systolic pressure,diastolic blood pressure,pulse pressure difference,mesangial cells proliferation,capillary hyperplasia,tubular atrophy and interstitial fibrosis were significant different between CMIPrs16955379 C allele carriers and non carriers.Serum TC,diastolic pressure,BUN,Scr,UA,urine protein quantitative,renal dysfunction,urinary protein,segmental sclerosis,tubular atrophy and interstitial fibrosis were significant different between CMIPrs2925979 A allele carriers and non carriers.The TT genotype of CMIP rs16955379 and A allele carriers of CMIP rs2925979 were closely associated with dyslipidemia in Ig AN.The GG genotype CMIP rs2925979 and C allele carriers of CMIP rs16955379 can reduce the risk of dyslipidemia(P < 0.05,respectively).Multivariate linear regression analysis of Ig A nephropathy showed that serum TC level was associated with ALT,CMIPrs16955379 with C allele,hypertention,alcohol and UA.Serum TG level was associated with ALT,renal function decline,CMIPrs16955379 C alleles,alcohol consumption,smoking,BMI,UA,and renal tubular interstitial disease.Serum HDL level was associated with ALT,CMIPrs16955379 C allele,UA,renal progression,mesangial cell proliferation and capillary hyperplasia.Serum LDL level was associated with CMIPrs16955379 C allele carrying,Hypertention,ALT and UA levels.Serum Apo A1 level was associated with BIM level and renal dysfunction.Serum Apo B level was associated with renal dysfunction,weight,and CMIP rs2925979 A allele carrying.Apo A1/ Apo B level was associated with renal dys function and hypertention(P <0.05,respectively).There was a LD between CMIP rs16955379 and rs2925979,and rs2925979G-rs16955379 T was the commonest haplotype.The haplotype frequencies of CMIP SNPs were significantly different between dyslipidemia and normal group in Ig AN(P < 0.05).Conclusion: About half of Ig AN patients had dyslipidemia,those patients with dyslipidemia had higher blood pressure,worse renal function,and more obvious hematuria,and more serious renal tubular interstitial damage.The patients with dyslipidemia presented poor clinical features and pathologic results.The genotypic and allelic frequencies of CMIP rs16955379 were significant different between normal and dyslipidemia group in Ig AN.There were significant different in several serum lipid level between CMIP SNPs different allele carriers.Linkage disequilibra analysis showed that the two loci(CMIP rs2925979 and CMIP rs16955379)in strong LD.The commonest haplotype was rs2925979g-rs16955379 t.The related haplotypes increased the risk of dyslipidemia in Ig AN.