Defining genetic risk factors for scleroderma-associated interstitial lung disease : IRF5 and STAT4 gene variants are associated with scleroderma while STAT4 is protective against scleroderma-associated interstitial lung disease

Sex Bias in Systemic Sclerosis: from Clinical to Immunological Differences

Systemic sclerosis (SSc) is a chronic autoimmune disease characterized by microvasculopathy, extensive fibrosis, and autoantibodies. The disease affects mostly the female sex. In this review, we highlight sex bias in clinical manifestations in SSc, and the pathophysiological changes underlying this bias. Male sex is associated with the diffuse cutaneous form of the disease, digital ulcers, interstitial lung disease, and worse prognosis. These clinical differences can be attributed to sex hormones and sex chromosomes, as females differ from males in sex hormones (estrogens in females, androgens in males) and sex chromosomes (XX in females, XY in males). Estrogens in females generally have immunostimulatory and profibrotic effects, and androgens have immunosuppressive effects. The X-chromosome contains many immunity-related genes, but the double dose of X-linked genes in females is avoided by random inactivation of one X-chromosome (XCI). However, many X-linked immunity-related genes, including toll-like receptor (TLR)7, TLR8 and Bruton's tyrosine kinase (BTK), escape XCI resulting in a biallelic expression with pathophysiological implications. Also, autosomal genes are differentially expressed between sexes. Therefore, sex should be included in future studies on SSc to aid in forming predictive algorithms and helping therapeutic decisions in this difficult-to-treat disease.

Pathogenesis of interstitial lung disease in systemic sclerosis

Interstitial lung disease (ILD) is a frequent important complication of systemic sclerosis (SSc). Factors relevant to aetiopathogenesis of SSc are also central to SSc-ILD. Severity of SSc-ILD is variable but it has a major impact on morbidity and mortality. Factors determining SSc-ILD susceptibility reflect the genetic architecture of SSc and are increasingly being defined. There are aspects linked to immunogenomics and non-immunological genetic factors that may be less conserved and underlie some of the geographical and racial diversity of SSc. These associations may also underlie important links between autoantibody subgroups and patient level risk of SSc-ILD. Examination of blood and tissue samples and observational clinical research together with integrated analysis of in vitro and in vivo preclinical models have elucidated pathogenic mechanisms of SSc-ILD. These have confirmed the potential importance of immune mechanisms in the innate and adaptive immune systemic as well as a significant role for profibrotic pathways especially transforming growth factor beta (TGFbeta) and its regulators and downstream mediators. Recent analysis of clinical trial cohorts as well as integrated and multilevel high dimensional analysis of bio-samples has shed further light on SSc-ILD. This is likely to underpin future advances in stratified and precision medicine for treatment of SSc.

Immunogenetics of Systemic Sclerosis

Systemic sclerosis (SSc) is a rare autoimmune connective tissue disorder characterized by massive fibrosis, vascular damage, and immune imbalance. Advances in rheumatology and immunology over the past two decades have led to a redefinition of systemic sclerosis, shifting from its initial perception as primarily a "hyperfibrotic" state towards a recognition of systemic sclerosis as an immune-mediated disease. Consequently, the search for genetic markers has transitioned from focusing on fibrotic mechanisms to exploring immune regulatory pathways. Immunogenetics, an emerging field at the intersection of immunology, molecular biology, and genetics has provided valuable insights into inherited factors that influence immunity. Data from genetic studies conducted thus far indicate that alterations in genetic messages can significantly impact disease risk and progression. While certain genetic variations may confer protective effects, others may exacerbate disease susceptibility. This paper presents a comprehensive review of the most relevant genetic changes that influence both the risk and course of systemic sclerosis. Special emphasis is placed on factors regulating the immune response, recognizing their pivotal role in the pathogenesis of the disease.

Therapeutic Approaches for the Treatment of Interstitial Lung Disease: An Exploratory Review on Molecular Mechanisms

BACKGROUND

Interstitial Lung Diseases (ILDs) are characterized by shortness of breath caused by alveolar wall inflammation and/or fibrosis.

OBJECTIVE

Our review aims to study the depth of various variants of ILD, diagnostic procedures, pathophysiology, molecular dysfunction and regulation, subject and objective assessment techniques, pharmacological intervention, exercise training and various modes of delivery for rehabilitation.

METHOD

Articles are reviewed from PubMed and Scopus and search engines.

RESULTS

ILD is a rapidly progressing disease with a high mortality rate. Each variant has its own set of causal agents and expression patterns. Patients often find it challenging to self-manage due to persistent symptoms and a rapid rate of worsening. The present review elaborated on the pathophysiology, risk factors, molecular mechanisms, diagnostics, and therapeutic approaches for ILD will guide future requirements in the quest for innovative and tailored ILD therapies at the molecular and cellular levels.

CONCLUSION

The review highlights the rationale for conventional and novel therapeutic approaches for better management of ILD.

Single nucleotide polymorphisms in cytokine genes and their association with primary Sjögren's syndrome in Saudi patients: A cross-sectional study

OBJECTIVES

To determine the allelic frequencies and effects of genotypic variations in cytokine gene polymorphisms in a Saudi Arabian population.

METHODS

This cross-sectional study involved 41 patients with Primary Sjögren's syndrome (pSS) and 71 healthy controls between October 2018 and May 2019. Single nucleotide polymorphisms genotyping was performed using the SEQUENOM MassARRAY® System, targeting nine polymorphisms in different cytokine genes. Chi-square tests were used to compare the patients and controls.

RESULTS

The interleukin-1 beta (IL-1β) rs1143627 CT (control, 52.7%; patients, 21.2%) and TT + CT (p= 0.003; p=0.033) genotypes were less frequent in patients with pSS than in healthy controls. The C allele in rs10488631 in the interferon regulatory factor 5 (IRF5) gene and the A allele in rs12583006 in the B-cell activating factor (BAFF) gene were associated with an increased risk of pSS development in the patient group.

CONCLUSION

The CT genotype at -31 (rs1143627) in the IL-1β gene was not associated with a high risk of pSS development in the Saudi population, in contrast to what has been verified in other ethnicities. However, the C allele in rs10488631 in IRF-5 and the A allele in rs12583006 in BAFF were associated.

Exome sequencing link mutation in RGPD4 with systemic sclerosis-associated interstitial lung disease and the low level of testosterone—an exploration study

Background

Interstitial lung disease (ILD) is the most common and potentially most devastating manifestation of SSc in pulmonary involvement. However, the mechanism for systemic sclerosis-associated ILD (SSc-ILD) is unclear. This work aims to explore the potential candidates for SSc-ILD upon whole exome sequencing (WES) and attempts to analyze the possible pathogenesis of SSc-ILD from the perspective of the genetic level.

Materials

Variants were confirmed by whole exome sequencing (WES), and SKAT analysis was employed to explore the most differential variants. Targeted variants were performed in biological functions, associated with clinical manifestations, and the probable change of downstream.

Results

By WES and SKAT analysis of SSc with and without ILD, only the variants of RGPD4 achieved statistical power (P < 2.51 × 10^-6, P-FDR = 0.025, OR = 15.95). A total of 20 rare functional variants (missense, truncating, splicing) were tested for the RGPD4 gene, and five truncating and damaging missense variants were identified. Carriers showed the older inclusion age (P = 0.02) and the higher frequency use of prednisone (P=0.02) compared to the non-carriers. Further analysis illustrated that carriers showed lower levels of TES in comparison to non-carriers but did not reach statistical difference (P = 0.08). In bivariate correlation analysis, we analyzed the relationship between the mutant status of RGPD4 and the levels of sex hormones after adjusting for age confounders. Only the level of TES showed a negative correlation with the mutant status (B = -0.509, P = 0.037).

Conclusion

The variants of RGPD4 might contribute to the ILD development of SSc and might also be a causative factor of lower TES among SSc-ILD, which provided insight to a better understanding of pathobiology of SSc-ILD, and androgen hormone supplement might be a therapeutic target in this debilitating disease.

Recent advances in elucidating the genetic basis of systemic sclerosis

PURPOSE OF REVIEW

Systemic sclerosis (SSc) is a complex autoimmune disorder that affects the connective tissue and causes severe vascular damage and fibrosis of the skin and internal organs. There are recent advances in the field that apply novel methods to high throughput genotype information of thousands of patients with SSc and provide promising results towards the use of genomic data to help SSc diagnosis and clinical care.

RECENT FINDINGS

This review addresses the development of the first SSc genomic risk score, which can contribute to differentiating SSc patients from healthy controls and other immune-mediated diseases. Moreover, we explore the implementation of data mining strategies on the results of genome-wide association studies to highlight subtype-specific HLA class II associations and a strong association of the HLA class I locus with SSc for the first time. Finally, the combination of genomic data with transcriptomics informed drug repurposing and genetic association studies in well characterized SSc patient cohorts identified markers of severe complications of the disease.

SUMMARY

Early diagnosis and clinical management of SSc and SSc-related complications are still challenging for rheumatologists. The development of predictive models and tools using genotype data may help to finally deliver personalized clinical care and treatment for patients with SSc in the near future.

Cellular and Molecular Diversity in Scleroderma

With the increasing armamentarium of high-throughput tools available at manageable cost, it is attractive and informative to determine the molecular underpinnings of patient heterogeneity in systemic sclerosis (SSc). Given the highly variable clinical outcomes of patients labelled with the same diagnosis, unravelling the cellular and molecular basis of disease heterogeneity will be crucial to predicting disease risk, stratifying management and ultimately informing a patient-centered precision medicine approach. Herein, we summarise the findings of the past several years in the fields of genomics, transcriptomics, and proteomics that contribute to unraveling the cellular and molecular heterogeneity of SSc. Expansion of these findings and their routine integration with quantitative analysis of histopathology and imaging studies into clinical care promise to inform a scientifically driven patient-centred personalized medicine approach to SSc in the near future.

Type I interferon detection in autoimmune diseases: challenges and clinical applications

INTRODUCTION

Accumulating data highlights that the dysregulation of type I interferon (IFN) pathways plays a central role in the pathogenesis of several systemic and organ-specific autoimmune diseases. Advances in understanding the role of type I IFNs in these disorders can lead to targeted drug development as well as establishing potential disease biomarkers.

AREAS COVERED

Here, we summarize current knowledge regarding the role of type I IFNs in the major systemic, as well as organ-specific, autoimmune disorders, including prominent inflammatory CNS disorders like multiple sclerosis.

EXPERT OPINION

Type I IFN involvement and its clinical associations in a wide spectrum of autoimmune diseases represents a promising area for research aiming to unveil common pathogenetic pathways in systemic and organ-specific autoimmunity.

Role of JAK/STAT in Interstitial Lung Diseases; Molecular and Cellular Mechanisms

Interstitial lung diseases (ILDs) comprise different fibrotic lung disorders characterized by cellular proliferation, interstitial inflammation, and fibrosis. The JAK/STAT molecular pathway is activated under the interaction of a broad number of profibrotic/pro-inflammatory cytokines, such as IL-6, IL-11, and IL-13, among others, which are increased in different ILDs. Similarly, several growth factors over-expressed in ILDs, such as platelet-derived growth factor (PDGF), transforming growth factor β1 (TGF-β1), and fibroblast growth factor (FGF) activate JAK/STAT by canonical or non-canonical pathways, which indicates a predominant role of JAK/STAT in ILDs. Between the different JAK/STAT isoforms, it appears that JAK2/STAT3 are predominant, initiating cellular changes observed in ILDs. This review analyzes the expression and distribution of different JAK/STAT isoforms in ILDs lung tissue and different cell types related to ILDs, such as lung fibroblasts and alveolar epithelial type II cells and analyzes JAK/STAT activation. The effect of JAK/STAT phosphorylation on cellular fibrotic processes, such as proliferation, senescence, autophagy, endoplasmic reticulum stress, or epithelial/fibroblast to mesenchymal transition will be described. The small molecules directed to inhibit JAK/STAT activation were assayed in vitro and in in vivo models of pulmonary fibrosis, and different JAK inhibitors are currently approved for myeloproliferative disorders. Recent evidence indicates that JAK inhibitors or monoclonal antibodies directed to block IL-6 are used as compassionate use to attenuate the excessive inflammation and lung fibrosis related to SARS-CoV-2 virus. These altogether indicate that JAK/STAT pathway is an attractive target to be proven in future clinical trials of lung fibrotic disorders.

Genetic Susceptibility to Antisynthetase Syndrome Associated With Single-Nucleotide Variants in the IL1B Gene That Lead Variation in IL-1β Serum Levels

The antisynthetase syndrome (ASSD) is an autoimmune disorder characterized by myositis, arthritis, mechanic's hands, fever, Raynaud phenomenon, and interstitial lung disease (ILD). We aimed to evaluate single-nucleotide polymorphisms in the interleukin 1B (IL1B) gene and their association between ILD with antisynthetase autoantibodies, as well as IL-1β serum levels. The most frequent antisynthetase autoantibody was anti-Jo1. The most frequent tomographic pattern was non-specific interstitial pneumonia, whereas in the anti-Jo1 subjects, it was organized pneumonia. Anti-Jo1 patients tend to have more significant arthritis, and Raynaud phenomenon have higher levels of creatinine phosphokinase. In the IL1B gene, the GG genotype and G allele of rs1143634 [odds ratio (OR) = 2.21 and OR = 2.60, respectively, p < 0.05] are associated with an increased risk, as well as with the dominant and recessive models (p < 0.05). This finding is maintained after logistic regression analysis adjusting for potential confounding variables (p < 0.05). Subjects with the rs16944/AG heterozygous genotype had higher serum levels of IL-1β compared to homozygous (p < 0.05). In conclusion, rs1143634 is associated with a higher risk of ASSD. Also, the GA genotype is associated with higher levels of IL-1β in ASSD patients.

Interstitial Lung Disease in Patients With Systemic Sclerosis: Toward Personalized-Medicine-Based Prediction and Drug Screening Models of Systemic Sclerosis-Related Interstitial Lung Disease (SSc-ILD)

Systemic sclerosis (SSc) is an autoimmune connective tissue disease, characterized by immune dysregulation and progressive fibrosis. Interstitial lung disease (ILD) is the most common cause of death among SSc patients and there are currently very limited approved disease-modifying treatment options for systemic sclerosis-related interstitial lung disease (SSc-ILD). The mechanisms underlying pulmonary fibrosis in SSc-ILD are not completely unraveled, and knowledge on fibrotic processes has been acquired mostly from studies in idiopathic pulmonary fibrosis (IPF). The incomplete knowledge of SSc-ILD pathogenesis partly explains the limited options for disease-modifying therapy for SSc-ILD. Fibrosis in IPF appears to be related to aberrant repair following injury, but whether this also holds for SSc-ILD is less evident. Furthermore, immune dysregulation appears to contribute to pro-fibrotic responses in SSc-ILD, perhaps more than in IPF. In addition, SSc-ILD patient heterogeneity complicates the understanding of the underlying mechanisms of disease development, and more importantly, limits correct clinical diagnosis and treatment effectivity. Therefore, there is an unmet need for patient-relevant (in vitro) models to examine patient-specific disease pathogenesis, predict disease progression, screen appropriate treatment regimens and identify new targets for treatment. Technological advances in in vitro patient-relevant disease modeling, including (human induced pluripotent stem cell (hiPSC)-derived) lung epithelial cells, organoids and organ-on-chip technology offer a platform that has the potential to contribute to unravel the underlying mechanisms of SSc-ILD development. Combining these models with state-of-the-art analysis platforms, including (single cell) RNA sequencing and (imaging) mass cytometry, may help to delineate pathogenic mechanisms and define new treatment targets of SSc-ILD.

Systemic sclerosis-associated interstitial lung disease

PURPOSE OF REVIEW

In this review, the authors discuss systemic sclerosis-associated interstitial lung disease (SSc-ILD) with a focus on recent developments in diagnosis, surveillance, and management.

RECENT FINDINGS

With advances in the management of SSc, the importance of ILD has been increasingly recognized and is the leading cause of mortality. Early detection is essential, and a combination of lung function testing and chest imaging are key tools in diagnosis and surveillance. The foundation of treatment is immunomodulation with recent studies identifying several potential new agents. The use of therapies targeting pro-fibrotic pathways have demonstrated significant effects on lung function decline and represent the latest advance in therapy for SSc-ILD.

SUMMARY

Recent studies support the use of newer therapies in SSc-ILD including antifibrotic agents. The identification and management of comorbidities is important, and lung transplantation is a viable option for patients with advanced disease.

Histopathology and genetic susceptibility in COVID-19 pneumonia

BACKGROUND

The clinical features of COVID-19 pneumonia range from a mild illness to patients with a very severe illness with acute hypoxemic respiratory failure requiring ventilation and Intensive Care Unit admission.

AIMS

To provide a brief overview of the existing evidence for such differences in host response and outcome, and generate hypotheses for divergent patterns and avenues for future research, by highlighting similarities and differences in histopathological appearance between COVID-19 and influenza as well as previous coronavirus outbreaks, and by discussing predisposition through genetics and underlying disease.

MATERIALS AND METHOD

We assessed the available early literature for histopathological patterns of COVID-19 pneumonia and underlying risk factors.

RESULT

The histopathological spectrum of COVID-19 pneumonia includes variable patterns of epithelial damage, vascular complications, fibrosis and inflammation. Risk factors for a fatal disease include older age, respiratory disease, diabetes mellitus, obesity and hypertension.

DISCUSSION

While some risk factors and their potential role in COVID-19 pneumonia are increasingly recognized, little is known about the mechanisms behind episodes of sudden deterioration or the infrequent idiosyncratic clinical demise in otherwise healthy and young subjects.

CONCLUSION

The answer to many of the remaining questions regarding COVID-19 pneumonia pathogenesis may in time be provided by genotyping as well careful clinical, serological, radiological and histopathological phenotyping.