Genetics, Epigenetics, and Gender Impact in Axial-Spondyloarthritis Susceptibility: An Update on Genetic Polymorphisms and Their Sex Related Associations

RNA-Based Antipsoriatic Gene Therapy: An Updated Review Focusing on Evidence from Animal Models

Psoriasis presents as a complex genetic skin disorder, characterized by the interaction between infiltrated immune cells and keratinocytes. Substantial progress has been made in understanding the molecular mechanisms of both coding and non-coding genes, which has positively impacted clinical treatment approaches. Despite extensive research into the genetic aspects of psoriasis pathogenesis, fully grasping its epigenetic component remains a challenging endeavor. In response to the pressing demand for innovative treatments to alleviate inflammatory skin disorders, various novel strategies are under consideration. These include gene therapy employing antisense nucleotides, silencing RNA complexes, stem cell therapy, and antibody-based therapy. There is a pressing requirement for a psoriasis-like animal model that replicates human psoriasis to facilitate early preclinical evaluations of these novel treatments. The authors conduct a comprehensive review of various gene therapy in different psoriasis-like animal models utilized in psoriasis research. The animals included in the list underwent skin treatments such as imiquimod application, as well as genetic and biologic injections, and the results of these interventions are detailed. Animal models play a crucial role in translating drug discoveries from the laboratory to clinical practice, and these models aid in improving the reproducibility and clinical applicability of preclinical data. Numerous animal models with characteristics similar to those of human psoriasis have proven to be useful in understanding the development of psoriasis. In this review, the article focuses on RNA-based gene therapy exploration in different types of psoriasis-like animal models to improve the treatment of psoriasis.

Risankizumab Efficacy in Synovitis, Acne, Pustulosis, Hyperostosis, and Osteitis (SAPHO) Remission: A Case Report on Rheumatologic and Dermatologic Disease Manifestations with Literature Review

SAPHO syndrome is a complex disease that encompasses both inflammatory arthritis and/or osteitis and dermatologic manifestations. It is considered a rare disease, in fact, no clinical trials have been conducted on its therapy and management. Therefore, therapeutic approach is based on small case studies. Here, we described the case of a 63-year-old woman affected by SAPHO syndrome, treated with the selective IL-23p19 antagonist, Risankizumab, after unsuccessful therapies with Methotrexate, Infliximab, Adalimumab, and an allergic reaction to Secukinumab. At the beginning of therapy, in November 2022, the patient presented with arthritis in both knees associated with palmar pustulosis and guttate psoriasis on the trunk. DAPSA score was 24, PtGA 80 mm, PASI score 11.1, and BSA 40%. Thereafter, Risankizumab was started at the standard dosage of 150 mg. At week 24 patient achieved clinical remission, DAPSA score was 8, PtGA was 30 mm, PASI was 1, and BSA 2.5. Patient maintained clinical remission state at the subsequent week 52 evaluation. At the same time, the patient did not report any adverse effects. Health-related quality of life was also assessed at the same time points aforementioned, showing significant improvement. In conclusion, this case report wants to point out the efficacy and safety of Risankizumab in SAPHO syndrome, reporting a sustained disease remission through a 12 months long follow-up period. We can consider IL-23p19 targeted therapy as a novel treatment option for SAPHO-with a high efficacy potential-especially on patients that have already been treated with other biologics.

Sensitivity and Specificity of Composite Indices of Remission in Male and Female Patients With Psoriatic Arthritis: A Multicenter Cross-Sectional Study of Longitudinal Cohorts

OBJECTIVE

The aim was to evaluate the sex differences in sensitivity, specificity, positive and negative predictive values, and likelihood ratio of the outcome indices minimal disease activity (MDA), Disease Activity Score for Psoriatic Arthritis (DAPSA), and Psoriatic Arthritis Impact of Disease (PsAID) with respect to clinical remission, evaluated from both the physician and patient perspective, in a multicenter cohort of patients with PsA.

METHODS

In this cross-sectional analysis of 2 longitudinal cohorts, all patients with PsA consecutively attending our rheumatology units were considered potentially eligible for the study. In all patients, a complete clinical examination was carried out. The DAPSA was calculated for each patient (DAPSA values ≤ 4 were considered as remission) and MDA was also evaluated. Patient and physician global assessment values ≤ 1 were considered as a surrogate of remission from the patient and physician perspective, respectively.

RESULTS

Two hundred seventy-two patients with PsA were enrolled (mean age 55.7 [SD 12.4]; 141 male, 131 female). In both sexes, MDA had good sensitivity and specificity toward remission as assessed by the rheumatologist. Remission according to DAPSA had excellent values of specificity but lacks sensitivity in both sexes. PsAID ≤ 4 had excellent values of sensitivity but lacked specificity in both sexes. Remission defined by DAPSA values was found to be more sensitive and specific in female patients (45.4% and 100%, respectively) than in male patients (33.3% and 84.2%, respectively) with respect to physician-judged remission.

CONCLUSION

The results of this study demonstrate for the first time, to our knowledge, that some differences between the 2 sexes on the different outcome indices are possible. This could be important in the clinical management of patients with PsA.

Impact of biological therapy in reducing the risk of arthritis development in inflammatory bowel diseases

OBJECTIVE

Evaluate spondyloarthritis (SpA) incidence in inflammatory bowel diseases (IBD) between patients treated with biological disease-modifying antirheumatic drugs (bDMARDs) and conventional DMARDs (cDMARDs) and define risk factors associated with SpA development.

METHODS

Retrospective cohort study was conducted on patients with Crohn's disease (CD) or ulcerative colitis (UC) and divided into two cohorts: cDMARDs or bDMARDs/targeted synthetic (ts) DMARDs treated patients. Rheumatological assessment was performed in patients presenting musculoskeletal symptoms. Multivariate analysis and Kaplan-Meier curves were used to evaluate the adjusted SpA risk development.

RESULTS

507 patients were included in the study. 176 patients with CD received bDMARDs, 112 cDMARDs and 106 new SpA diagnosies were formulated. Females (OR 1.7 (95% CI 1.1 to 3), adjusted p=0.04), non-stricturing/non-penetrating phenotype (OR 2 (95% CI 1.1 to 3.4), adjusted p=0.01), psoriasis (OR 2.1 (95% CI 1 to 4.6), adjusted p=0.04) and non-infectious uveitis (OR 6.8 (95% CI 1.4 to 33.4), adjusted p=0.01) were associated with increased SpA risk development, while bDMARDs usage was protective (OR 0.4 (95% CI 0.2 to 0.8), adjusted p=0.01), statistically higher than cDMARDs throughout the entire follow-up (effect size 0.47). 98 patients with UC received b-tsDMARDs, 121 cDMARDs and 56 new SpA diagnoses were formulated. Females (OR 2.1 (95% CI 1 to 4.3), adjusted p=0.02) and psoriasis (OR 2.7 (95% CI 1 to 6.8), adjusted p=0.03) were associated with increased SpA risk development, while bDMARDs were protective for SpA development for up to 12 months of treatment compared with cDMARDs (p=0.03).

CONCLUSIONS

bDMARDs treatment had an impact in reducing SpA development and clinical associated risk factors to transition from IBD to IBD-SpA emerged.

Beyond the horizon: Innovations and future directions in axial-spondyloarthritis

Axial spondyloarthritis (axSpA) is a chronic inflammatory disease of the spine and sacroiliac joints. This review discusses recent advances across multiple scientific fields that promise to transform axSpA management. Traditionally, axSpA was considered an immune-mediated disease driven by human leukocyte antigen B27 (HLA-B27), interleukin (IL)-23/IL-17 signaling, biomechanics, and dysbiosis. Diagnosis relies on clinical features, laboratory tests, and imaging, particularly magnetic resonance imaging (MRI) nowadays. Management includes exercise, lifestyle changes, non-steroidal anti-inflammatory drugs and if this is not sufficient to achieve disease control also biological and targeted-synthetic disease modifying anti-rheumatic drugs. Beyond long-recognized genetic risks like HLA-B27, high-throughput sequencing has revealed intricate gene-environment interactions influencing dysbiosis, immune dysfunction, and aberrant bone remodeling. Elucidating these mechanisms promises screening approaches to enable early intervention. Advanced imaging is revolutionizing the assessment of axSpA's hallmark: sacroiliac bone-marrow edema indicating inflammation. Novel magnetic resonance imaging (MRI) techniques sensitively quantify disease activity, while machine learning automates complex analysis to improve diagnostic accuracy and monitoring. Hybrid imaging like synthetic MRI/computed tomography (CT) visualizes structural damage with new clarity. Meanwhile, microbiome analysis has uncovered gut ecosystem alterations that may initiate joint inflammation through HLA-B27 misfolding or immune subversion. Correcting dysbiosis represents an enticing treatment target. Moving forward, emerging techniques must augment patient care. Incorporating patient perspectives will be key to ensure innovations like genetics, microbiome, and imaging biomarkers translate into improved mobility, reduced pain, and increased quality of life. By integrating cutting-edge, multidisciplinary science with patients' lived experience, researchers can unlock the full potential of new technologies to deliver transformative outcomes. The future is bright for precision diagnosis, tightly controlled treatment, and even prevention of axSpA.

Differences of RUNX2 gene promoter methylation and transcription level in ankylosing spondylitis

BACKGROUND AND OBJECTIVE

Ankylosing spondylitis is a refractory immune disease that seriously affects the life and work of patients. Epigenetic modifications, especially DNA methylation, have become a research hotspot in complex diseases. We aim to explore the changes in runt-related transcription factor 2 (RUNX2) gene promoter methylation and transcription level in AS.

METHOD

We detected the RUNX2 gene promoter methylation in 83 AS patients and 83 healthy controls (HCs), then inspected the mRNA difference of RUNX2 between 30 AS patients and 30 HCs by the quantitative real-time reverse transcription polymerase chain reaction (qRT-PCR).

RESULTS

The RUNX2 gene promoter was hypomethylated in AS patients compared to HCs (p < .001). The research involved 4 CpG regions and 74 CpG sites of RUNX2, of which CpG-2, CpG-4 regions, and 18 CpG sites have been differentially methylated. The CpG-4 island methylation was negatively correlated with C-reactive protein (p < .05) in AS patients. In the qRT-PCR validation phase, the mRNA level of RUNX2 in AS patients was significantly higher than HCs (p < .05), and in AS patients who were treated with biologics, the methylation level of CpG-2 island showed a negative correlation to mRNA (p < .05). ROC results indicated that RUNX2 methylation and its transcription level have good potential to distinguish AS patients from HCs.

CONCLUSION

The RUNX2 gene promoter was hypomethylated in AS patients. Meanwhile, the qRT-PCR verified the up-regulated expression on the transcription level, suggesting the abnormal methylation of RUNX2 contributes to the pathogenesis of AS.

Emerging Concepts in Precision Medicine in Axial Spondyloarthritis

PURPOSE OF REVIEW

Axial spondyloarthritis (AxSpA) is among the rheumatology's most heritable complex diseases, yet precision medicine at clinics still needs to be explored. We reviewed the emerging concepts and recent developments in polygenic risk scores, Mendelian randomization, pharmacogenomics, single-cell sequencing, and spatial transcriptomics.

RECENT FINDINGS

Polygenic risk score has resulted in encouraging results with potential diagnostic utility as it appears to outperform current diagnostic tools. Its performance and generalizability vary with ethnicity. Mendelian randomization has elucidated multiple causal associations, particularly between inflammatory bowel disease and AxSpA. Single-cell transcriptomics (particularly scRNA-seq and scATAC-seq) has identified numerous cell types, including synovial and blood immunological cells, to understand the contribution of both innate and adaptative immunity in AxSpA. Current molecular tools provide an exciting opportunity to advance precision medicine for AxSpA patients. However, extensive research and implementation strategies are still required before they can have an impact in the clinic.

Genetic and Molecular Distinctions Between Axial Psoriatic Arthritis and Radiographic Axial Spondyloarthritis: Post Hoc Analyses from Four Phase 3 Clinical Trials

INTRODUCTION

Emerging evidence suggests psoriatic arthritis (PsA) with axial involvement (axPsA) and radiographic axial spondyloarthritis (r-axSpA) may possibly represent distinct disorders, with some differing clinical manifestations, genetic associations, and radiographic findings. Moreover, axPsA and r-axSpA may respond differently to therapies: guselkumab (interleukin [IL]-23p19 subunit inhibitor [i]) and ustekinumab (IL-12/23p40i) demonstrated improvements in axial symptoms in patients with PsA; however, neither risankizumab (IL-23p19i) nor ustekinumab demonstrated efficacy versus placebo in patients with r-axSpA. Current analyses aim to further understand potential molecular distinctions between axPsA and r-axSpA and examine the pharmacodynamic effects of guselkumab in patients with axPsA and those with PsA without axial involvement (non-axPsA).

METHODS

Post hoc analyses utilized biomarker data from blood and serum samples collected from a subset of participants in phase 3 studies of ustekinumab in r-axSpA and guselkumab in PsA (DISCOVER-1 and DISCOVER-2). Participants with axPsA were identified by investigator-verified sacroiliitis (imaging-confirmed) and axial symptoms. HLA mapping, serum cytokine analysis, and whole-blood RNA sequencing were conducted.

RESULTS

Relative to r-axSpA, patients with axPsA had a lower prevalence of HLA-B27, HLA-C01, and HLA-C02 alleles and a higher prevalence of HLA-B13, HLA-B38, HLA-B57, HLA-C06, and HLA-C12 alleles. Compared with r-axSpA, patients with axPsA had elevated baseline levels of serum IL-17A and IL-17F cytokines, enrichment of IL-17 and IL-10 pathway-associated genes, and neutrophil gene markers. Across axPsA and non-axPsA cohorts, reductions in cytokine levels and normalization of pathway-associated gene expression with guselkumab treatment were comparable.

CONCLUSION

The differences in HLA genetic associations, serum cytokines, and enrichment scores support the concept that axPsA and r-axSpA may be distinct disorders. The comparable pharmacodynamic effects of guselkumab on cytokine levels and pathway-associated genes observed in patients with axPsA and non-axPsA are consistent with demonstrated clinical improvements across PsA cohorts. These findings contribute to the understanding of potential genetic and molecular distinctions between axPsA and r-axSpA.

TRIAL REGISTRATION

ClinicalTrials.gov identifiers, NCT03162796, NCT0315828, NCT02437162, and NCT02438787.

JAK-STAT signaling pathway-related gene single nucleotide polymorphisms and susceptibility to ankylosing spondylitis in eastern Chinese Han population

OBJECTIVE

A case-control study was utilized to investigate the relationship between genetic variation of JAK-STAT signaling pathway-related genes and the susceptibility to ankylosing spondylitis (AS).

METHODS

Fifteen SNPs in the JAK-STAT signaling pathway-related genes from 660 AS patients and 646 healthy controls were genotyped using iMLDR technology (JAK1: rs2230587, rs2230588, rs2780815, rs310241; JAK2: rs2274472, rs2230722, rs2230724, rs10758669; STAT1: rs10199181, rs1547550, rs2066802, rs45463799, rs6718902; STAT3: rs3744483; STAT5A: rs1135669).

RESULTS

Allele analysis revealed that the T allele of STAT1 rs6718902 was a protective agent for male AS patients (OR = 0.765, 95% CI = 0.644-0.909). Inheritance models showed that GG + CG as well as GG genotypes of STAT1 rs1547550 had a significant risk of developing AS in males (OR = 5.374, 95%CI = 2.505-11.526; OR = 5.186, 95%CI = 2.412-11.153). The TT + CT and TT genotypes at STAT1 rs6718902 were observed to be associated with a significantly decreased risk of AS compared to CC genotypes among male patients and male controls (OR = 0.637, 95%CI = 0.485-0.837; OR = 0.597, 95%CI = 0.422-0.845). Furthermore, the genotypes of JAK1 gene rs2230588, rs2780815, and rs310241 were correlated with the severity of clinical conditions in female AS patients, while the JAK2 rs2230724 genotypes may affect disease ability in male AS patients.

CONCLUSION

These findings indicated that JAK-STAT signaling pathway-related gene single nucleotide polymorphisms may be associated with AS susceptibility in eastern Chinese Han population. Key Points • The T allele of rs6718902 on the STAT1 gene may be a protective agent for male AS patients. • STAT1 rs1547550 GG + CG and GG genotypes were observed to be connected with a risk of male AS patients. However, STAT1 rs6718902 TT + CT and TT genotypes reduced the susceptibility risk of male AS patients compared to wild-type CC. • The JAK1 genes rs2230588, rs2780815, and rs310241 may affect disease functional status in female AS patients, while the JAK2 rs2230724 genotype was related to disease activity in male AS patients.

How Has Molecular Biology Enhanced Our Undertaking of axSpA and Its Management

PURPOSE

This review aims at investigating pathophysiological mechanisms in spondyloarthritis (SpA). Analysis of genetic factors, immunological pathways, and abnormalities of bone metabolism lay the foundations for a better understanding of development of the axial clinical manifestations in patients, allowing physician to choose the most appropriate therapeutic strategy in a more targeted manner.

RECENT FINDINGS

In addition to the contribution of MHC system, findings emerged about the role of non-HLA genes (as ERAP1 and 2, whose inhibition could represent a new therapeutic approach) and of epigenetic mechanisms that regulate the expression of genes involved in SpA pathogenesis. Increasing evidence of bone metabolism abnormalities secondary to the activation of immunological pathways suggests the development of various bone anomalies that are present in axSpA patients. SpA are a group of inflammatory diseases with a multifactorial origin, whose pathogenesis is linked to the genetic predisposition, the action of environmental risk factors, and the activation of immune response. It is now well known how bone metabolism leads to long-term structural damage via increased bone turnover, bone loss and osteoporosis, osteitis, erosions, osteosclerosis, and osteoproliferation. These effects can exist in the same patient over time or even simultaneously. Evidence suggests a cross relationship among innate immunity, autoimmunity, and bone remodeling in SpA, making treatment approach a challenge for rheumatologists. Specifically, treatment targets are consistently increasing as new drugs are upcoming. Both biological and targeted synthetic drugs are promising in terms of their efficacy and safety profile in patients affected by SpA.

Identification of gut dysbiosis in axial spondyloarthritis patients and improvement of experimental ankylosing spondyloarthritis by microbiome-derived butyrate with immune-modulating function

Introduction

Dysbiosis is an environmental factor that affects the induction of axial spondyloarthritis (axSpA) pathogenesis. In the present study, we investigated differences in the gut microbiota of patients with axSpA and revealed an association between specific gut microbiota and their metabolites, and SpA pathogenesis.

Method

Using 16S rRNA sequencing data derived from feces samples of 33 axSpA patients and 20 healthy controls (HCs), we examined the compositions of their gut microbiomes.

Results

As a result, axSpA patients were found to have decreased α-diversity compared to HCs, indicating that axSpA patients have less diverse microbiomes. In particular, at the species level, Bacteroides and Streptococcus were more abundant in axSpA patients than in HCs, whereas Faecalibacterium (F). prausnitzii, a butyrate-producing bacteria, was more abundant in HCs. Thus, we decided to investigate whether F. prausnitzii was associated with health conditions by inoculating F. prausnitzii (0.1, 1, and 10 μg/mL) or by administrating butyrate (0.5 mM) into CD4⁺ T cells derived from axSpA patients. The levels of IL-17A and IL-10 in the CD4⁺ T cell culture media were then measured. We also assessed osteoclast formation by administrating butyrate to the axSpA-derived peripheral blood mononuclear cells. The CD4⁺ IL-17A⁺ T cell differentiation, IL-17A levels were decreased, whereas IL-10 was increased by F. prausnitzii inoculation. Butyrate reduced CD4⁺ IL-17A⁺ T cell differentiation and osteoclastogenesis.

Discussion

We found that CD4⁺ IL-17A⁺ T cell polarization was reduced, when F. prausnitzii or butyrate were introduced into curdlan-induced SpA mice or CD4⁺ T cells of axSpA patient. Consistently, butyrate treatment was associated with the reduction of arthritis scores and inflammation levels in SpA mice. Taken together, we concluded that the reduced abundance of butyrate-producing microbes, particularly F. prausnitzii, may be associated with axSpA pathogenesis.

Central Obesity in Axial Spondyloarthritis: The Missing Link to Understanding Worse Outcomes in Women?

OBJECTIVE

To determine (1) the prevalence of central obesity in axial spondyloarthritis (axSpA) and its effect on disease-related outcomes and (2) how this differs between sexes.

METHODS

Data were extracted from the Ankylosing Spondylitis Registry of Ireland. Patients with physical measurements for the calculation of anthropometric measures were included. BMI and waist-to-hip ratio (WHR) were used to compare classifications of obesity. Comparison analyses based on sex and central obesity were carried out. Multivariate analysis examined the effects of these factors on the following patient-reported outcomes: the Bath Ankylosing Spondylitis Disease Activity Index (BASDAI), the Bath Ankylosing Spondylitis Functional Index (BASFI), the Ankylosing Spondylitis Quality of Life (ASQoL) questionnaire, and the Health Assessment Questionnaire (HAQ).

RESULTS

In total, 753 patients were included in the analysis. Of these patients, 29.6% (n = 223) were classified as obese based on their BMI, and 41.3% (n = 311) were classified as centrally obese according to the WHR. The prevalence of central obesity was significantly higher among women with axSpA compared to men (71.6% vs 29.9%, P < 0.01). Central obesity had a clear effect on patient outcomes, regardless of sex. Presence of central obesity was associated with significantly worse BASFI scores (P < 0.01), HAQ scores (P < 0.01), and ASQoL questionnaire scores (P = 0.01), with a nonsignificant trend toward worse BASDAI scores (P = 0.07).

CONCLUSION

There was a high prevalence of central obesity as assessed by the WHR in axSpA, most notably among women with axSpA. This modifiable comorbidity was significantly associated with worse quality of life, greater impairment of functional ability, and a trend toward worse disease activity. Regular use of the WHR to screen for central obesity as part of an axSpA assessment would provide an opportunity for prompt identification and intervention for at-risk patients.

An Update Evolving View of Copy Number Variations in Autoimmune Diseases

Autoimmune diseases (AIDs) usually share possible common mechanisms, i.e., a defect in the immune tolerance exists due to diverse causes from central and peripheral tolerance mechanisms. Some genetic variations including copy number variations (CNVs) are known to link to several AIDs and are of importance in the susceptibility to AIDs and the potential therapeutic responses to medicines. As an important source of genetic variants, DNA CNVs have been shown to be very common in AIDs, implying these AIDs may possess possible common mechanisms. In addition, some CNVs are differently distributed in various diseases in different ethnic populations, suggesting that AIDs may have their own different phenotypes and different genetic and/or environmental backgrounds among diverse populations. Due to the continuous advancement in genotyping technology, such as high-throughput whole-genome sequencing method, more susceptible variants have been found. Moreover, further replication studies should be conducted to confirm the results of studies with different ethnic cohorts and independent populations. In this review, we aim to summarize the most relevant data that emerged in the past few decades on the relationship of CNVs and AIDs and gain some new insights into the issue.