Chen-Chen Feng

Gene-gene and gene-sex epistatic interactions of MiR146a, IRF5, IKZF1, ETS1 and IL21 in systemic lupus erythematosus.

Several confirmed genetic susceptibility loci involved in the interferon signaling and Th17/B cell response for SLE in Chinese Han populations have been described. Available data also indicate that sex-specific genetic differences contribute to SLE susceptibility. The aim of this study was to test for gene–gene/gene-sex epistasis (interactions) in these known lupus susceptibility loci. Six single-nucleotide polymorphisms (SNPs) in MiR146a, IRF5, IKZF1, ETS1 and IL21 were genotyped by Sequenom MassArray system. A total of 1,825 subjects (858 SLE patients and 967 controls) were included in the final analysis. Epistasis was tested by additive model, multiplicative model and multifactor dimensionality reduction (MDR) method. Additive interaction analysis revealed interactions between IRF5 and IKZF1 (OR 2.26, 95% CI 1.48–3.44 [P = 1.21×104]). A similar tendency was also observed between IL21 and ETS1 by parametric methods. In addition, multiple high dimensional gene-gene or gene-sex interactions (three-and four-way) were identified by MDR analysis. Our study identified novel gene–gene/gene-sex interactions in lupus. Furthermore, these findings highlight sex, interferon pathway, and Th17/B cells as important contributors to the pathogenesis of SLE.

The dual nature of Ets-1: focus to the pathogenesis of systemic lupus erythematosus.

E26 transformation-specific-1 (Ets-1) belongs to the Ets family of transcription factors which share a common 85-amino-acid DNA-binding domain. Ets-1 is essential to regulation of the immune system including immune cell proliferation and differentiation. Past data demonstrated Ets-1 play a role in negative regulation of Th17 cells and B cells differentiation. Recently, association of genetic variation in Ets-1 with susceptibility to systemic lupus erythematosus (SLE) have been independently identified by two Genome-wide association studies (GWAS), and decreased Ets-1mRNA level in peripheral blood mononuclear cells (PBMCs) of SLE patients has been reported. All these findings suggest that the transcription factor is broadly linked to the pathogenesis of this disease. However, aberrant control of other immune cells and effector molecules illuminated the complexities of Ets-1 biology. In this review article, we will focus on the dual nature of Ets-1 and discuss its regulatory capability. Hopefully the information obtained will lead to a better understanding of the pathogenesis and development of novel therapeutic strategies for SLE.

IL-32 with potential insights into rheumatoid arthritis

Rheumatoid arthritis (RA) is an autoimmune disease, characterized by chronic inflammation in synovial joints. Effective treatment for RA is lacking because the clear etiology and pathogenesis of RA have not been fully elucidated. Cytokine-mediated immunity has been found to play an important role in the pathogenesis of various autoimmune diseases such as RA. Recently, IL-32 is identified with high expression in RA patients and mice models of experimental inflammatory arthritis. IL-32 is recognized to play a crucial role in RA with pro-inflammatory effects. Furthermore, interventions for blocking IL-32 in RA seem possible and applicable. Therefore, targeting IL-32 may give therapeutic potential. In this article, we discuss the biological features of IL-32 and summarize recent advances in understanding the role of IL-32 in disease onset of and treatment for RA. Hopefully the information obtained will benefit for developing novel therapeutic strategies.

Expression profiles of Th17 pathway related genes in human systemic lupus erythematosus.

Recently, evidence is emerging that inappropriate regulation of type 17 T helper cells (Th17) plays a fundamental role in the development of many autoimmune diseases including systemic lupus erythematosus (SLE). However, the role of Th17-related cytokines in SLE remains elusive. To further investigate the role and imbalance of Th17-related cytokines in the pathogenesis of SLE. A Quantitative RT-PCR Array (Human Th17 for Autoimmunity & Inflammation PCR Array) analyses were performed to study Th17-related genes expression in peripheral white blood cells of 25 new-onset patients with SLE and 15 healthy subjects. When gene expression for SLE patients was compared to the mean of normal controls, among the 84 target genes related to Th17 pathway, 7 (CXCL1, ICAM1, IL10, IL5, IL8, ISG20, JAK2,) were upregulated and 6 (CD28, CD40LG, S1PR1, IL17RE, IL23R, RORC) downregulated. However, comparisons of mRNA expression of Th17 related cytokines between lupus nephritis (LN) patients and SLE patients without nephritis (SLE non LN) showed no significant difference. In conclusion, SLE patients and normal controls showed different expression of a few genes in Th17 pathway, indicating that the pathway may be involved in the pathogenesis of SLE.

Increased serum RANTES in patients with systemic lupus erythematosus

The aim of this study was to investigate the serum RANTES (regulated on activation, normal T-cell expressed and secreted) level in patients with systemic lupus erythematosus (SLE), and the associations with disease activity and clinical laboratory indexes. Twenty-seven SLE patients and 27 normal controls were enrolled in this study. Serum RANTES was measured by enzyme-linked immunosorbent assay (ELISA). The clinical and laboratory parameters of the patients were also recorded. Results showed that serum RANTES level was significantly elevated in SLE patients when compared with normal controls. Serum RANTES level was correlated with C3, ANA, anti-dsDNA antibodies, anti-Sm antibodies, and anti-SSB antibodies. Nevertheless, no association of serum RANTES level with SLEDAI was found. Taken together, serum RANTES level was significantly higher in SLE patients, suggesting that RANTES might be involved in the pathogenesis of SLE.

Genetic interaction between genes involved in NF-κB signaling pathway in systemic lupus erythematosus.

Recently, multiple genetic associations have been found between genes involved in nuclear factor-kappaB (NF-κB) signaling pathway and systemic lupus erythematosus (SLE) or other autoimmune diseases. This study was undertaken to replicate some of these associations and further test for genetic interactions among these genes in SLE in a Chinese population. Ten single-nucleotide polymorphisms (SNPs) in NFKB1, REL, inhibitor of κB-like (IκBL), IκB kinase β (IKBKB), tumor necrosis factor receptor associated factor 6 (TRAF6), tumor necrosis factor a-induced protein 3 (TNFAIP3), TNFAIP3 interacting protein 1 (TNIP1) were genotyped in 898 Chinese patients with SLE and 988 healthy controls by Sequenom MassArray technology. Single-marker genetic association analysis was performed, and additive and multiplicative interactions were analyzed. Associations of TNFAIP3 rs2230926 (p=1.43 × 10(-3)) and TNIP1 rs10036748 (p=4.33 × 10(-3)) with SLE were replicated in our study. Two other SNPs, NFKB1 rs28362491 and IκBL rs2071592, showed nominal evidence for association (p=4.70 × 10(-2) and p=5.90 × 10(-3), respectively) but these were not significant after applying Bonferroni correction. Additive interaction analysis revealed significant interaction between NFKB1 rs28362491 and TNFAIP3 rs2230926 (RERI=0.98, 95%CI=0.02-1.93; AP=43.2%, 95%CI=0.12-0.74). Significant multiplicative interaction was observed between NFKB1 rs28362491 and TNIP1 rs3792783 (p=0.03). Our results provide evidence for gene-gene interactions, which further support the important role of NF-κB signaling pathway in the genetic basis of SLE and the notion of genetic interactions accounting for missing heritability.

D18S880 microsatellite polymorphism of carnosinase gene and diabetic nephropathy: a meta-analysis.

OBJECTIVE The aim of this study was to determine whether the CNDP1 (carnosinase gene) D18S880 microsatellite polymorphism confers susceptibility to diabetic nephropathy (DN). METHODS The authors conducted meta-analysis on association between the CNDP1 D18S880 microsatellite polymorphism and DN susceptibility, using fixed and random effects models. RESULTS A total of nine comparative studies were included in this meta-analysis, which included 4546 DN, 7994 diabetes mellitus (DM), and 1826 healthy (Heal) subjects. Overall, the analysis revealed that the D18S880 microsatellite polymorphism was significantly associated with DN for the five trinucleotide repeat (5L) allele and five leucines repeat (5L-5L) homozygous in the comparisons of DN versus DM (5L: odds ratio [OR] 0.90, 95% confidence interval [CI] 0.84-0.97, p=0.008; 5L-5L: OR 0.88, 95% CI 0.81-0.97, p=0.006) and DN versus non-DN (DM+Heal) (5L: OR 0.92, 95% CI 0.86-0.98, p=0.009; 5L-5L: OR 0.89, 95% CI 0.82-0.96, p=0.004). The protective effects of the D18S880 polymorphism were similar to those observed in the subgroups of the type 2 DM and the Caucasian population. However, significant association was not found in the type 1 DM population. CONCLUSIONS This meta-analysis confirms that the carnosinase D18S880 microsatellite polymorphism is associated with DN susceptibility, especially in the type 2 DM and the Caucasian population.

The TLR7 7926A>G polymorphism is associated with susceptibility to systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is a systemic autoimmune disorder that predominantly affects women of childbearing age, with a female-to-male ratio of approximately 9:1. Previous findings indicated that male cases of SLE were associated with Klinefelters syndrome (47, XXY), whereas females with Turners syndrome (45, X0) did not contract SLE. Additionally, duplicated Toll-like receptor 7 (TLR7) was found to promote lupus-like disease. Consequently, the aim of this study was to evaluate whether the TLR7 gene served as a genetic marker for the development of SLE. A case-control study was performed on one tag single nucleotide polymorphism TLR7 rs1634323 in a population with 507 SLE patients and 513 healthy controls. Genotyping was determined by the TaqMan genotyping assay using the ABI 7300 real-time reverse transcription polymerase chain reaction system. The results showed a significantly elevated risk of SLE with the rs1634323 AG genotype in females (P = 0.040, OR = 1.897, 95% CI 1.031-3.491), whereas a similar association was not replicated in males (P = 0.303, OR = 0.338, 95% CI 0.043-2.656). In a subgroup analysis by clinical manifestation of lupus nephritis, no significant differences were found. These findings indicate that the TLR7 gene rs1634323 polymorphism may contribute to SLE susceptibility in females.

Association of FAS gene polymorphisms with systemic lupus erythematosus: A case-control study and meta-analysis

The association of functional polymorphisms in the promoter of the apoptosis gene FAS with systemic lupus erythematosus (SLE) susceptibility has been a controversial subject. We conducted a case-control study to investigate this association in a Chinese population and performed a meta-analysis in different populations. The single nucleotide polymorphisms (SNPs) rs2234767 (−1377G>A) and rs1800682 (−670A>G) were genotyped by TaqMan allelic discrimination assays in 552 Chinese SLE patients and 718 healthy controls. In our case-control study, we observed allelic association between the promoter SNP rs2234767 [P=0.033, odds ratio (OR)=0.836, 95% confidence interval (CI), 0.709–0.986] and SLE but not the SNP rs1800682. Haplotype analysis revealed that one haplotype of GA was significantly associated with the disease (P=0.039, OR=1.184, 95% CI, 1.009–1.391). In the meta-analysis available studies, including our data, were combined using the STATA software package v.7.0. The meta-analysis revealed a significant association between FAS polymorphisms and SLE (rs2234767 A vs. G allele; P=0.004, OR=0.819, 95% CI, 0.715–0.938, rs1800682 G vs. A allele: P=0.034, OR=0.791, 95% CI, 0.637–0.983). In conclusion, FAS gene polymorphisms may contribute to SLE susceptibility in the Chinese population, and the meta-analysis shows that FAS polymorphisms may be associated with SLE susceptibility in different populations.

The association of IL1α and IL1β polymorphisms with susceptibility to systemic lupus erythematosus: A meta-analysis

Many epidemiological studies have investigated IL1α and IL1β polymorphisms with SLE risk, but no conclusions are available because of conflicting results. This meta-analysis was performed to more precisely estimate the relationships. The databases of PubMed updated to September 1st, 2012 were retrieved. Odds ratio (OR) and corresponding 95% confidence interval (95% CI) as effect size were calculated by a fixed- or random-effect model. In total, six case-control studies for IL1β-511C/T, four studies for IL1β+3953C/T, three studies for IL1α-889C/T and three studies for IL1α+4845G/T were involved in this analysis. The results indicated that for IL1α-889C/T polymorphism T allele was associated with decreased risk of SLE (OR (95% CI)) (T vs. C: 0.802 (0.679-0.949); TT+CT vs. CC: 0.615 (0.380-0.995); TT vs. CC: 0.679 (0.466-0.989)). However, when analysis for TT vs. CT+CC was conducted, the result indicated that IL1α-889C/T polymorphism was not associated with SLE (OR (95% CI): 0.847 (0.595-1.205)). Combined analysis indicated that IL1β-511C/T polymorphism was not overall associated with risk of SLE (OR (95% CI)) (T vs. C: 1.113 (0.954-1.298); TT vs. CT+CC: 1.146 (0.889-1.447); TT+CT vs. CC: 1.145 (0.903-1.452); TT vs. CC: 1.255 (0.928-1.698)). When subgroup analysis for Asian ethnicity was conducted, the results indicated that IL1β-511C/T polymorphism was associated with SLE only for TT vs. CT+CC (OR (95% CI): 1.468 (1.001-2.152)), but was not associated for T vs. C (OR (95% CI): 1.214 (0.955-1.544)), TT+CT vs. CC (OR (95% CI): 1.112 (0.765-1.615)) and TT vs.CC (OR (95% CI): 1.411 (0.896-2.222)). In addition, overall analyses indicated that IL1β+3953C/T and IL1α+4845G/C polymorphisms were also not associated with risk of SLE (OR (95% CI)) (for IL1β+3953C/T T vs. C: 0.996 (0.610-1.626), TT vs. CT+CC: 0.658 (0.318-1.358), TT+CT vs. CC: 1.021 (0.618-1.687), TT vs. CC: 0.640 (0.309-1.325); for IL1α+4845G/T T vs. G: 1.067 (0.791-1.440), TT+GT vs. GG: 0.934 (0.646-1.351)).This study inferred that IL1α-889C/T polymorphism might be moderately associated with SLE, but no sufficient evidence was available to support any associations between IL1β+3953C/T or IL1α+4845G/C polymorphisms and SLE. We could not draw a definite conclusion between IL1β-511C/T polymorphism and risk of SLE owing to the limited data. Further large sample-sized studies should be required.