Cross-Disease Innate Gene Signature: Emerging Diversity and Abundance in RA Comparing to SLE and SSc

Identification of biomarkers related to neutrophils and two molecular subtypes of systemic lupus erythematosus

Background

Systemic lupus erythematosus (SLE), an autoimmune disease with complex pathogenesis, poses a considerable threat to women’s health. Increasing evidence indicates that neutrophils play an important role in the development and progression of lupus.

Methods

Weighted correlation network analysis and single-sample gene set enrichment analysis (GSEA) were used to analyse SLE expression data from a comprehensive gene expression database and identify modules associated with neutrophils. Thereafter, the biomarkers most closely related to neutrophils were identified. We reclassified SLE into two molecular subtypes based on the aforementioned biomarkers and evaluated cell infiltration, molecular mechanisms, and signature pathways in each subtype.

Results

The results showed significant differences in immunological characteristics between the two molecular subtypes of SLE. Hub genes were significantly upregulated in the NEUT-H subtype, and they may be associated with lupus activity. The GSEA revealed associations between our biomarkers and key metabolic pathways.

Conclusions

Our study provides not only a classification for patients with SLE but also new cell and gene targets for immunotherapy, as well as a new experimental paradigm to explore immunotherapy for other autoimmune diseases.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12920-022-01306-9.

Single Immunoglobulin IL-1-Related Receptor (SIGIRR) Gene rs7396562 Polymorphism and Expression Level in Rheumatoid Arthritis

Objectives

The aim of our study was to investigate the association of single-nucleotide polymorphism (SNP) and mRNA expression profile of single immunoglobulin IL-1-related receptor (SIGIRR) in rheumatoid arthritis (RA) in a Chinese population.

Methods

SIGIRR rs7396562 polymorphism was genotyped using TaqMan allelic discrimination assay in 517 RA patients and 601 healthy controls. Simultaneously, the SIGIRR mRNA expression levels of 79 RA patients and 76 healthy controls were examined by real-time quantitative polymerase chain reaction (RT-qPCR).

Results

The frequency of SIGIRR rs7396562 T allele was significantly higher in RA patients compared with healthy controls (T versus G: OR = 1.277, 95%CI = 1.079 - 1.511, P = 0.004). The TT genotype of SIGIRR rs7396562 was more frequent in RA patients than in healthy controls (OR = 1.547, 95%CI = 1.107 - 2.163, P = 0.011). Moreover, we also found a significant difference in the recessive model (TT versus TG+GG: OR = 1.439, 95%CI = 1.122 - 1.847, P = 0.004). However, no significant evidence was observed for the association of the SIGIRR rs7396562 with RA in dominant model (TT+TG versus GG: OR = 1.275, 95%CI = 0.947 - 1.717, P = 0.109). Further analysis showed no association between SIGIRR rs7396562 polymorphism and laboratory parameters of RA patients (all P > 0.05). The mRNA expression of SIGIRR was decreased in PBMCs of patients with RA when compared to healthy controls (Z = -2.459, P = 0.014). No significant differences in SIGIRR mRNA expression levels were observed in patients with RA with different genotypes (P = 0.280).

Conclusions

Our findings demonstrated that the dysregulation of SIGIRR might be associated with the pathogenesis of RA, and SIGIRR rs7396562 polymorphism might contribute to RA susceptibility in the Chinese population.

Effects of Biological Therapies on Molecular Features of Rheumatoid Arthritis

Rheumatoid arthritis (RA) is an autoimmune and chronic inflammatory disease primarily affecting the joints, and closely related to specific autoantibodies that mostly target modified self-epitopes. Relevant findings in the field of RA pathogenesis have been described. In particular, new insights come from studies on synovial fibroblasts and cells belonging to the innate and adaptive immune system, which documented the aberrant production of inflammatory mediators, oxidative stress and NETosis, along with relevant alterations of the genome and on the regulatory epigenetic mechanisms. In recent years, the advances in the understanding of RA pathogenesis by identifying key cells and cytokines allowed the development of new targeted disease-modifying antirheumatic drugs (DMARDs). These drugs considerably improved treatment outcomes for the majority of patients. Moreover, numerous studies demonstrated that the pharmacological therapy with biologic DMARDs (bDMARDs) promotes, in parallel to their clinical efficacy, significant improvement in all these altered molecular mechanisms. Thus, continuous updating of the knowledge of molecular processes associated with the pathogenesis of RA, and on the specific effects of bDMARDs in the correction of their dysregulation, are essential in the early and correct approach to the treatment of this complex autoimmune disorder. The present review details basic mechanisms related to the physiopathology of RA, along with the core mechanisms of response to bDMARDs.

Cannabinoids, Inner Ear, Hearing, and Tinnitus: A Neuroimmunological Perspective

Cannabis has been used for centuries for recreational and therapeutic purposes. Whereas, the recreative uses are based on the psychotropic effect of some of its compounds, its therapeutic effects range over a wide spectrum of actions, most of which target the brain or the immune system. Several studies have found cannabinoid receptors in the auditory system, both at peripheral and central levels, thus raising the interest in cannabinoid signaling in hearing, and especially in tinnitus, which is affected also by anxiety, memory, and attention circuits where cannabinoid effects are well described. Available studies on animal models of tinnitus suggest that cannabinoids are not likely to be helpful in tinnitus treatment and could even be harmful. However, the pharmacology of cannabinoids is very complex, and most studies focused on neural CB1R-based responses. Cannabinoid effects on the immune system (where CB2Rs predominate) are increasingly recognized as essential in understanding nervous system pathological responses, and data on immune cannabinoid targets have emerged in the auditory system as well. In addition, nonclassical cannabinoid targets (such as TRP channels) appear to play an important role in the auditory system as well. This review will focus on neuroimmunological mechanisms for cannabinoid effects and their possible use as protective and therapeutic agents in the ear and auditory system, especially in tinnitus.

High CXCR3 on Leukemic Cells Distinguishes IgHV mut from IgHV unmut in Chronic Lymphocytic Leukemia: Evidence from CD5high and CD5low Clones

Despite the shared pattern of surface antigens, neoplastic cells in chronic lymphocytic leukemia (CLL) are highly heterogeneous in CD5 expression, a marker linked to a proliferative pool of neoplastic cells. To further characterize CD5^high and CD5^low neoplastic cells, we assessed the chemokine receptors (CCR5, CCR7, CCR10, CXCR3, CXCR4, CXCR5) and adhesion molecules (CD54, CD62L, CD49d) on the CD5^high and CD5^low subpopulations, defined by CD5/CD19 coexpression, in peripheral blood of CLL patients (n = 60) subgrouped according to the IgHV mutational status (IgHV^mut, n = 24; IgHV^unmut, n = 36). CD5^high subpopulation showed a high percentage of CXCR3 (P < 0.001), CCR10 (P = 0.001), and CD62L (P = 0.031) and high levels of CXCR5 (P = 0.005), CCR7 (P = 0.013) compared to CD5^low cells expressing high CXCR4 (P < 0.001). Comparing IgHV^mut and IgHV^unmut patients, high levels of CXCR3 on CD5^high and CD5^low subpopulations were detected in the IgHV^mut patients, with better discrimination in CD5^low subpopulation. Levels of CXCR3 on CD5^low subpopulation were associated with time to the next treatment, thus further confirming its prognostic value. Taken together, our analysis revealed higher CXCR3 expression on both CD5^high and CD5^low neoplastic cells in IgHV^mut with a better prognosis compared to IgHV^unmut patients. Contribution of CXCR3 to CLL pathophysiology and its suitability for prognostication and therapeutic exploitation deserves future investigations.