Association Study Of Long Noncoding RNAs Expression Levels And Their Gene Single Nucleotide Polymorphisms With Rheumatoid Arthritis

Background Rheumatoid arthritis(RA)is a chronic autoimmune disease.It is characterized by autoantibodies,systemic inflammation and persistent synovitis,invades the small joints of limbs,and leads to eventual joint degradation,deformation,and loss of function.At present,the world prevalence of RA is approximately 1.0% among adults,the burden of the disease is heavy,the pathogenesis of disease is still unclear.The current study found that the incidence of RA may be related to environmental,genetic,autoimmune,endocrine abnormalities and infection factors,among them,genetic factor plays a crucial role in RA.The genetic background of RA disease is complex,involving both the encoding and noncoding genes.Encoding genes have been widely reported in previous studies,but the association of noncoding genes and RA is rare.Long noncoding RNAs(lnc RNAs)are defined as noncoding RNA that transcripts longer than 200 nucleotides,have a large number and a wide variety of species,and can participate in many biological processes such as gene transcription,RNA splicing,chromosome remodeling and protein transport from the following aspects: transcription level,post transcriptional level,protein metabolism and epigenetic level.Recently,a number of lnc RNAs have been proved to be stable in the peripheral blood mononuclear cells(PBMCs)and play an important role in regulating human immune system.They are thought to be involved in the pathogenesis of immune mediated inflammatory diseases.Recent researches indicated that lnc RNAs may also play a role in the pathogenesis of RA.ObjectiveTo compare the expression levels of lnc RNAs(linc0597,GAS5 and H19)in PBMCs of RA patients and healthy controls,and to explore the association between the lnc RNAs single nucleotide polymorphisms(SNP)and susceptibility to RA in a Chinese Han population.MethodsCase-control design was used in a two-stage study.In the first stage,the expression level of lnc RNAs in PBMCs of 77 RA cases and 78 healthy controls was detected by quantitative real-time polymerase chain reaction(q RT-PCR).In the second stage,we detected SNP in 626 RA cases and 650 healthy controls by Fluidigm EP1 platform and Taq Man SNP probe genotyping method.Epi Data 3.1 database was adopted to double entry questionnaire data,and SPSS 23.0 was used to analyze the data.α=0.05.Results(1)In the first stage,we detected the expression level of lnc RNAs in PBMCs of 77 RA cases and 78 healthy controls.It was found that the expression level of GAS5,linc0597 and H19 in PBMCs of RA cases was lower than that of healthy controls,the differences were statistically significant(Z=-4.821,P<0.001;Z=-6.095,P<0.001;Z=-2.330,P=0.020).The study further carried out the correlation analysis of the expression level of lnc RNAs with the main laboratory parameters,the degree of disease activity and the clinical medication of RA.It was found that the expression level of GAS5 was down-regulated(Z=-2.259,P=0.024)in RA patients with low complement,and was correlated with the level of C-reaction protein(CRP)(rs=-0.273,P=0.017).No significant association between linc0597 and H19 expression level and the main laboratory parameters,the degree of disease activity and the clinical medication of RA(all P>0.05).(2)In the second phase,we detected the lnc RNAs SNP of 626 RA cases and 650 healthy controls.The results showed that rs6790 of GAS5,rs2067051 and rs2075745 of H19,rs2070107,rs2877877,rs2632516 and rs2285991 of linc0597 before and after adjusting for gender and age,were found no differences in genotype frequencies,allele frequencies,dominant model,or recessive model among the RA and healthy controls(all P>0.05).There was no significant association between SNP and major laboratory indicators,such as RF and CCP in RA patients(all P>0.05).(3)There was no significant correlation between lncRNAs SNP and its expression level in PBMCs of 59 RA patients(all P>0.05).ConclusionsThe expression levels of GAS5,linc0597 and H19 in RA patients was down-regulated.The expression level of GAS5 was down-regulated in the RA with low complement,and was negatively correlated with the level of CRP in RA,further suggested that GAS5 may play an important role in the pathogenesis of RA.The SNP of GAS5,linc0597 and H19 were not associated with the susceptibility to RA.