Association Study Of Polymorphisms, MRNA Expression Of Peli-1 With Systemic Lupus Erythematosus

BackgroundSystemic lupus erythematosus(SLE) is a systemic autoimmune disease, characterized by a multitude of autoantibody production, complement activation and immune-complex deposition, resulting in multiple tissues and organs damage as well as physiological function impairment. SLE predominantly affects women. Recently, multiple studies explore the etiology and pathogenesis of SLE, but the exact mechanism of SLE has not been fully elucidated to date. The mechanism of SLE is complex, and both genetic factors andenvironmental agents are involved in the initiation and progression of this disease. These factors interact with each other and form a complex web, then causing increased release and production of inflammation cytokines. SLE was initially considered as a B cell-mediated autoimmune disease, with the deepening of research, T cells also have been found to play important roles in the development of SLE.In 1993, a new kind of highly conservative E3 ubiquitin ligase protein named Pellino was first discovered in drosophila. Three members of the Pellino family had been characterized, including Pellino1, Pellino2 and Pellino3. Most notably, Peli-1 plays diverse roles in both innate and adaptive immunity. Recent researches also have indentified that Pellino proteins can regulate TLR/IL-1R-mediated immune responses. Besides, Peli-1 has an essential role in mediating NF-κB activation by TRIF-dependentTLRs. In addition, Chang et al suggested a new function of Peli-1 in the maintenance of peripheral T-cell tolerance and regulation of T-cell activation.Based upon all these points, we first performed this study to explore that Peli-1 gene associated with the development of SLE through genetic susceptibility and m RNA levels.Part I Association study of Peli-1 single nucleotide polymorphism and Systemic lupus erythematosusObjective To explore the associations of two single nucleotide polymorphisms(rs329498, rs10496105) in Peli-1 gene with susceptibility to systemic lupus erythematosus in a Chinese Han population. Besides, we also determined whether an association existed between these two SNPs and the main clnical festures.Methods We conducted a case-control study and a total of 738 SLE patients and 827 healthy controls were finally recruited. Peli-1 rs329498, rs10496105 polymorphisms were specified from genomic DNA using Taq Man genotyping assay on Fluidigm 192.24 system.Results(1) Association analysis of Peli-1 rs329498 and SLEGenotypic frequencies for AA, AC, and CC in SLE group were 40.8%, 44.6%, and 14.6%, respectively. The control group was 36.5%, 45.5% and 18.0%, respectively. No significant difference was detected in the distribution of genotypic frequencies between SLE patients and controls(χ2=4.63, P=0.099). The allele contrast showed a significant difference between SLE patients and controls(χ2=4.80, P=0.028) and the minor allele C was associated with a 0.851 fold(95% CI: 0.737-0.983) risk for the susceptibility to SLE compared with the A allele. However, no significant differences were discovered in the dominant model, as well as in the recessive model. We compared the distributionwith respect to the allele and genotype frequencies of rs329498 polymorphism between LN patients and non-LN patients. We found an increased frequency of the major allele A in LN patients than in non-LN patients(χ2=8.18, P=0.017). Compared with major allele A, the minor allele C was associated with a 0.681-fold higher risk for the susceptibility to LN patients(95% CI: 0.528-0.880). Moreover, a significant difference was also detected under a dominant model with regard to the distribution of genotype frequencies between LN patients and non-LN patients(CC+AC versus AA: OR= 0.632, 95% CI: 0.451-0.884, P=0.007). Clinical features analysis showed a significant difference in the distribution of genotypic frequencies between patients with malar rash and patients without this feature(χ2=6.63, P=0.036).(2) Association analysis of Peli-1 rs10496105 and SLEWith regard to SNP rs10496105, genotype frequencies for GG, AG and AA were 70.0%, 26.2% and 3.8% in the SLE patients, 69.4%, 27.2% and 3.4% in controls, respectively. And there were no significant difference in the allelic distributions between them, as well as in the dominant model and recessive model(all P>0.05). In addition, no significant difference was detected in the genotype distribution between LN patients and non-LN patients either. Besides, we failed to found any positive results of rs10496105 with these main clinical symptoms of SLE(all P>0.05).Conclusion Peli-1 gene polymorphism rs329498 might contribute to SLE susceptibility in Chinese Population. Besides, the rs329498 SNP was also associated with LN and malar rash. However, we did not find any correlations between rs10496105 SNP and SLE susceptibility.Part Ⅱ Expression of Peli-1 m RNA in peripheral blood mononuclear cells from patients with Systemic lupus erythematosusObjective To compared the expression of Peli-1 m RNA between systemic lupus erythematosus(SLE) patients and controls, lupus nephritis(LN) group and non-LN group, active and inactive group, and explore the relationship between m RNA levels and clinical, laboratory data and disease activity.Methods A total of 31 SLE patients and 30 healthy controls were collected. The m RNA was extracted with Trizol from human peripheral blood mononuclear cells(PBMCs). By the relative quantitation PCR to detect the m RNA level in PBMCs. To compare the median m RNA level between different groups, the Mann-Whitney test was used. Spearman’s rank correlation coefficient was used to analysis the correlations between Peil-1 m RNA level and systemic lupus erythematosus disease activity index(SLEDAI). All the data were analyzed by the statistical software SPSS 17.0.Results(1) Peli-1 m RNA expression in PBMCsWith respect to the expression of m RNA in PBMCs, there was no statistical significant difference Between the 31 SLE patients and 30 healthy controls(Z=-0.404,P=0.686). No significant difference was observed between 11 LN patients and 20 non-LN patients(Z=-0.619,P=0.536). Besides, we did not find any difference between the 19 active and 12 inactive patients(Z=-0.973,P=0.330).(2) The relationship between Peli-1 m RNA levels and the main clinical featuresAccording to the results of Mann-Whitney test, there were no significant differences between Peli-1 m RNA levels and the main clinical features(all P>0.05).(3) The relationship between Peli-1 m RNA levels and the main laboratory featuresNo significant differences were detected between Peli-1 m RNA levels and the main laboratory features(all P>0.05).(4) Correlation analysis of Peli-1 m RNA expression in PBMCs from SLE patients and SLEDAISpearman rank correlation analysis results suggested that no significant positive correlation was found between Peli-1 m RNA expression in PBMCs from SLE patients and SLEDAI(rs=0.148, P=0.428).Conclusion The Peli-1 mRNA expression was not significantly different in SLE patients and healthy controls, as well as LN and non-LN groups, active and inactive groups. Moreover, this study did not found any significant associations of Peli-1 m RNA expression levels with several clinical and laboratory features. Besides, no significant positive correlation was found between Peli-1 m RNA expression in PBMCs from SLE patients and SLEDAI.