Association between cytokine gene polymorphisms and ankylosing spondylitis susceptibility: a systematic review and meta-analysis

Causal association of gut microbiota on spondyloarthritis and its subtypes: a Mendelian randomization analysis

Background

Despite establishing an association between gut microbiota and spondyloarthritis (SpA) subtypes, the causal relationship between them remains unclear.

Methods

Gut microbiota data were obtained from the MiBioGen collaboration, and SpA genome-wide association study (GWAS) summary data were obtained from the FinnGen collaboration. We conducted a two-sample Mendelian randomization (MR) analysis using the inverse-variance-weighted method supplemented with four additional MR methods (MR-Egger, weighted median, simple mode, and weighted mode). Pleiotropy and heterogeneity were also assessed. Reverse MR analysis was used to detect reverse causal relationships.

Results

We identified 23 causal links between specific gut microbiota taxa and SpA levels. Of these, 22 displayed nominal causal associations, and only one demonstrated a robust causal connection. Actinobacteria id.419 increased the risk of ankylosing spondylitis (AS) (odds ratio (OR) = 1.86 (95% confidence interval (CI): 1.29-2.69); p = 8.63E-04). The family Rikenellaceae id.967 was associated with a reduced risk of both AS (OR = 0.66 (95% CI: 0.47-0.93); p = 1.81E-02) and psoriatic arthritis (OR = 0.70 (95% CI: 0.50-0.97); p = 3.00E-02). Bacillales id.1674 increased the risk of AS (OR = 1.23 (95% CI: 1.00-1.51); p = 4.94E-02) and decreased the risk of enteropathic arthritis (OR = 0.56 (95% CI: 0.35-0.88); p = 1.14E-02). Directional pleiotropy, or heterogeneity, was not observed. No reverse causal associations were observed between the diseases and the gut microbiota.

Conclusion

Our MR analysis suggested a genetic-level causal relationship between specific gut microbiota and SpA, providing insights into the underlying mechanisms behind SpA development mediated by gut microbiota.

Single nucleotide polymorphisms in ADAM17, IL23R and SLCO1C1 genes protect against infliximab failure in adults with Crohn's disease

BACKGROUND

To predict primary failure of infliximab (IFX) therapy in Crohn's disease (CD) and to identify patients who maintain long-term effectiveness to IFX is currently not feasible. Some genetic variations are proposed as potential biomarkers.

AIM

We assessed a set of single nucleotide polymorphisms (SNPs) in genes related to the IFX mechanism of action and the presence of HLA-DQA1 * 05 allele on the primary response and long-term durability in CD patients.

METHODS

A multi-centre cross-sectional study of IFX-exposed adult patients with CD was undertaken. Treatment persistence and time to failure were co-primary endpoints. DNA from the 131 patients was genotyped. Association between SNPs and clinical variables with IFX persistence was assessed.

RESULTS

Failure to IFX was documented in 65 (49.6%) out of 131 patients. IFX persistence was associated either with carrying the TT genotype in ADAM17 rs10929587 (ORa=0.2; 95%CI=0.1-0.8; p = 0.021), or the CC genotype in SLCO1C1 rs3794271 (ORa=0.2; 95%CI=0.1-0.7; p = 0.008), according to multivariate logistic regression. In contrast, previous bowel resection increased the risk of IFX failure (ORa=2.8; 95%CI=1.1-7.3; p = 0.025). Cox regression analysis confirmed these findings and also identified IL23R rs10489629-TT (HRa 0.41; 95%CI=0.22-0.75; p = 0.004) and concomitant immunosuppressants (HRa 0.46; 95%CI=0.27-0.77; p = 0.003) as protection from IFX failure. However, no association between HLA-DQA1 * 05 allele and persistence of IFX therapy was found, with similar failure rates among carriers and non-carriers (52.8% vs. 47.4%, respectively; p = 0.544).

CONCLUSIONS

SNPs rs10929587-TT in ADAM17, rs10489629-TT in IL23R and rs3794271-CC in SLCO1C1, together with no previous bowel surgery and concomitant immunosuppression, were identified as protection from failure to IFX.

The Potential Role of Genetics, Environmental Factors, and Gut Dysbiosis in the Aberrant Non-Coding RNA Expression to Mediate Inflammation and Osteoclastogenic/Osteogenic Differentiation in Ankylosing Spondylitis

Ankylosing spondylitis (AS) or radiographic axial spondyloarthritis is a chronic immune-mediated rheumatic disorder characterized by the inflammation in the axial skeleton, peripheral joints, and soft tissues (enthesis, fascia, and ligament). In addition, the extra-skeletal complications including anterior uveitis, interstitial lung diseases and aortitis are found. The pathogenesis of AS implicates an intricate interaction among HLA (HLA-B27) and non-HLA loci [endoplasmic reticulum aminopeptidase 1 (ERAP1), and interleukin-23 receptor (IL23R), gut dysbiosis, immune plasticity, and numerous environmental factors (infections, heavy metals, stress, cigarette smoking, etc.) The latter multiple non-genetic factors may exert a powerful stress on epigenetic regulations. These epigenetic regulations of gene expression contain DNA methylation/demethylation, histone modifications and aberrant non-coding RNAs (ncRNAs) expression, leading to inflammation and immune dysfunctions. In the present review, we shall discuss these contributory factors that are involved in AS pathogenesis, especially the aberrant ncRNA expression and its effects on the proinflammatory cytokine productions (TNF-α, IL-17 and IL-23), T cell skewing to Th1/Th17, and osteoclastogenic/osteogenic differentiation. Finally, some potential investigatory approaches are raised for solving the puzzles in AS pathogenesis.

A meta-analysis for association of TNF-α -308G>A polymorphism with susceptibility to Ankylosing Spondylitis

Objective

We performed a meta-analysis of all eligible studies on the association of TNF-α -308G>A polymorphism with risk of Ankylosing spondylitis (AS).

Methods

A comprehensive literature research was performed in online databases.

Results

A total of 28 studies with 4489 cases and 5919 controls were included. Pooled ORs showed a significant association between TNF-α -308G>A polymorphism and risk of AS. Moreover, stratified analysis by ethnicity showed a significant association between TNF-α -308G>A polymorphism and AS risk in Asians, Caucasians and Mixed populations, but not in Chinese population.

Conclusion

This meta-analysis suggested that the TNF-α -308G>A polymorphism was associated with AS risk.

Advances in our understanding of gout as an auto-inflammatory disease

Gout, the most common inflammatory arthritis, is the result of hyperuricemia and inflammation induced by monosodium urate (MSU) crystal deposition. However, most people with hyperuricemia will never develop gout, implying a molecular-genetic contribution to the development of gout. Recent genomic studies reveal links between certain genetic variations and gout. We highlight recent advances in our understanding of gout as an auto-inflammatory disease. We review the auto-inflammatory aspects of gout, including the inflammasome and thirteen gout-associated inflammatory-pathway genes and associated comorbidities. This information provides important insights into emerging immune-modulating targets in the management of gout, and future novel therapeutic targets in gout treatment. Cumulatively, this has important implications for treating gout as an auto-inflammatory disease, as opposed to a purely metabolic disease.

Association between interleukin-1, interleukin-6, and tumor necrosis factor-alpha polymorphisms and juvenile idiopathic arthritis: a meta-analysis

INTRODUCTION

In juvenile idiopathic arthritis (JIA), interleukin (IL)-1, IL-6, and tumor necrosis factor-alpha (TNF-α) are associated with development and progression of JIA. We investigated whether IL-1, IL-6, and TNF-α polymorphisms were associated with susceptibility to JIA.

EVIDENCE ACQUISITION

A meta-analysis was conducted on the associations between IL-1α-899 C/T, IL-1β-511 C/T, IL-6-174 G/C, and TNF-α-308 G/A and -238 G/A polymorphisms, and JIA (PubMed and Embase).

EVIDENCE SYNTHESIS

A total of 27 studies involving 4678 JIA patients and 7634 controls were considered in the meta-analysis. There was no association between the IL-1α-899 C/T, IL-1β-511 C/T, IL-6-174 G/C, and TNF-α-308 G/A and -238 G/A polymorphisms, and JIA in allele contrast or any other genetic models. In subgroup analysis based on subtype, except for the dominant model of TNF-α-238 G/A, systemic JIA was not significantly associated with IL-6 and TNF-α polymorphisms. In Caucasians, the dominant and additive models of IL-1β-511 C/T were significantly associated with JIA (odds ratio [OR] 1.48, 95% confidence interval [CI] 1.09-2.00, P=0.01; OR 1.46, 95% CI 1.05-2.03, P=0.02, respectively).

CONCLUSIONS

This meta-analysis showed no association between IL-1, IL-6, and TNF-α polymorphisms, and JIA, but the TT genotype of IL-1β -511 C/T was associated with higher prevalence of JIA in Caucasians.