Usefulness of Cytokine Gene Polymorphisms for the Therapeutic Choice in Japanese Patients with Rheumatoid Arthritis

The 5' untranslated region variant rs3811050 C/T of the interleukin-38 encoding gene is associated with susceptibility to rheumatoid arthritis in Iraqi women

BACKGROUND

Interleukin (IL)-38, the latest member of the IL-1 cytokine family, is proposed to have a pathogenic role in rheumatoid arthritis (RA). It is encoded by the IL1F10 gene, which harbors single nucleotide polymorphisms (SNPs) that may predict the risk of autoimmune diseases. Among them are 5' untranslated region (UTR) SNPs, which play a key role in post-transcriptional control, but have not been studied in Iraqi RA patients.

METHODS

Two novel IL1F10 5'UTR SNPs (rs3811050 C/T and rs3811051 T/G) were explored in RA and control women (n = 120 and 110, respectively). SNPs were genotyped using TaqMan assay. An ELISA kit was used to measure serum IL-38 concentrations.

RESULTS

A reduced risk of RA was associated with rs3811050 T allele and CT genotype (corrected probability [pc] = 0.01 and < 0.001, respectively), while there was no significant association with rs3811051. Haplotype analysis demonstrated that C-T haplotype was associated with a 1.65-fold greater risk of RA, whereas a reduced risk was linked to T-G haplotype. IL-38 concentrations were higher in patients than in controls (p < 0.001). In addition, IL-38 showed acceptable performance in distinguishing between RA and control women (p < 0.001). When IL-38 concentrations were stratified according to SNP genotypes, no significant differences were found.

CONCLUSIONS

The rs3811050 variant was more likely to affect RA susceptibility in Iraqi women, and the T allele may play a role in reducing disease risk. IL-38 concentrations were elevated in RA patients, but were not affected by the rs3811050 and rs3811051 genotypes.

Naringenin ameliorates collagen-induced arthritis through activating AMPK-mediated autophagy in macrophages

BACKGROUND

Naringenin is widely recognized for its notable attributes, including anti-inflammatory, anti-cancer, and immunomodulatory activities. However, its specific implications for rheumatoid arthritis (RA) and the underlying mechanisms remain to be explored. This study aimed to investigate the therapeutic efficacy and pharmacological mechanism of Naringenin in the treatment of collagen-induced arthritis (CIA).

METHODS

A CIA model was established in DBA/1 mice, and various doses of Naringenin were administered orally to assess its impact on RA. The study also involved lipopolysaccharides (LPS)-induced RAW264.7 cells to further evaluate the effects of Naringenin. Mechanistic studies were conducted to elucidate the signaling pathways involved in Naringenin's actions.

RESULTS

Naringenin significantly alleviated foot inflammation in DBA/1 CIA mice and attenuated the levels of pro-inflammatory cytokines in serum. It also enhanced antioxidant capacity in the CIA model. In vitro studies with LPS-induced RAW264.7 cells demonstrated that Naringenin attenuated pro-inflammatory cytokines and reactive oxygen species (ROS) levels. Mechanistic studies confirmed that Naringenin activated autophagy and increased autophagic flux. Blocking autophagy, either by silencing Atg5 or inhibiting autophagolysosome using chloroquine, effectively counteracted the impact of Naringenin on pro-inflammatory cytokines. Further exploration revealed that Naringenin activated the AMPK/ULK1 signaling pathway, and inhibition of AMPK reversed the initiation of autophagy and reduced pro-inflammatory cytokine secretion induced by Naringenin.

CONCLUSIONS

This study unveils a novel mechanism by which Naringenin may be used to treat RA. It demonstrates the therapeutic efficacy of Naringenin in a CIA model by reducing inflammation, modulating cytokine levels, and enhancing antioxidant capacity. Moreover, the activation of autophagy through the AMPK/ULK1 signaling pathway appears to play a critical role in Naringenin's anti-inflammatory effects. These findings suggest potential strategies for the development of anti-rheumatic medications based on Naringenin.

Interferon-gamma (IFN-γ) intronic variant (rs2430561) is a risk factor for systemic lupus erythematosus: Observation from a meta-analysis

BACKGROUND

The role of interferon-gamma (IFN-γ) in autoimmune disorders has been well documented. Elevated levels of IFN-γ are observed in rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE) and are linked with disease severity. Single nucleotide polymorphism in the intronic region of the IFN-γ gene (+874 T>A rs2430561) has been associated with susceptibility to the development of RA and SLE; however, the reports remained contradictories. We conducted a meta-analysis using earlier published articles to reach a valid conclusion on the role of IFN-γ polymorphism (+874 T>A) in autoimmune diseases.

MATERIALS AND METHODS

Various online databases such as PubMed, Google Scholar, Science Direct, and Scopus were searched to find eligible reports for inclusion in the present analysis. Two independent authors extracted eligible studies and data. The meta-analysis was performed by comprehensive meta-analysis software (CMA) v.3.1. Trial sequential analysis was performed to test whether enough case-control studies have already been conducted worldwide to reach a valid observation.

RESULTS

Six published reports on the role of IFN-γ +874 T>A in SLE and four in RA were found after searching various databases. However, out of those six studies in SLE, in one study, the distribution of genotypes was not following the hardy-Weinberg equilibrium. In RA, three studies were deviated out of four reports. Thus, a total of five studies comprising 1440 SLE patients and 1748 controls were considered for the present meta-analysis. Meta-analysis showed a significant association between IFN-γ +874 T>A variants with susceptibility to SLE (homozygous comparison: p = 0.036, OR = 1.592, heterozygous model: p = 0.042, OR = 1.507, dominant model: p = 0.002, OR = 1.309).

CONCLUSIONS

IFN-γ +874 T>A variant is associated with predisposition to SLE development.

Association between the interferon-γ +874 T/A polymorphism and susceptibility to systemic lupus erythematosus and rheumatoid arthritis: A meta-analysis

We aimed to determine whether the interferon (IFN)-γ +874 T/A polymorphism (rs2430561) is associated with susceptibility to systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA). A meta-analysis was conducted to assess the association between the IFN-γ +874 T/A polymorphism and SLE or RA using allele contrast, homozygous contrast, recessive, and dominant models. A total of nine studies (six on SLE and three on RA), involving 1839 patients and 2272 controls, were included in the meta-analysis. The meta-analysis revealed a significant association between SLE and the TT genotype of the IFN-γ +874 T/A polymorphism (odds ratio [OR] = 0.751, 95% confidence interval [CI] = 0.634-0.899, p = .001), and stratification by ethnicity indicated an association between the IFN-γ +874 TT genotype and the Asian population. The analysis also revealed a significant association between SLE and the TT + TA genotype of the IFN-γ +874 T/A polymorphism in Arab populations (OR = 1.598, 95% CI = 1.053-2.425, p = .028). However, no association between the IFN-γ +874 T/A polymorphism and RA was found using allele contrast, recessive, dominant or homozygous contrast models in all study subjects and ethnic groups. This meta-analysis demonstrated that the IFN-γ +874 T/A polymorphism is associated with susceptibility to SLE in Asian and Arab populations.

Effect of Cytokine Gene Polymorphisms on Eltrombopag Reactivity in Japanese Patients with Immune Thrombocytopenia

Background

Immune thrombocytopenic purpura (ITP) is an autoimmune disease characterized by low platelet counts resulting from antiplatelet autoantibodies. Analysis of polymorphisms in cytokine-encoding genes is important for understanding the pathophysiology of ITP and selecting appropriate treatments. We investigated associations between polymorphisms in cytokine-encoding genes and responses to therapy in Japanese patients with ITP.

Methods

The participants in this study comprised 153 patients with ITP and 70 healthy controls. We extracted data on sex, age, platelet counts, bleeding symptoms, and therapeutic responses, including those to prednisolone (PSL) and eltrombopag. Genomic DNA was isolated from peripheral blood and polymorphisms in TNF-α, IL-10, TGF-β₁, and IFN-γ genes were analyzed using the PCR-SSP method.

Results

Our results showed that the TGF-β₁ +869 C/C genotype might be related to ITP in Japanese patients. The IL-10 -592 C/C and A/A, -819 C/C and T/T, and -1082, -819, -592 ATA/ATA genotypes might be associated with reactivity to PSL. Furthermore, the IL-10 -592 C/A -819 C/T genotypes, IL-10 ACC/ATA genotype, and TGF-β₁ +869 T/T and T/C genotypes might be linked to the response to eltrombopag.

Conclusion

Our results indicate that analysis of polymorphisms in cytokine-encoding genes could aid in understanding PSL and eltrombopag responsiveness in Japanese patients with ITP.