The Role of IL-36 in the Pathophysiological Processes of Autoimmune Diseases

Interleukin-1 receptor accessory protein blockade limits the development of atherosclerosis and reduces plaque inflammation

AIMS

The interleukin-1 receptor accessory protein (IL1RAP) is a co-receptor required for signalling through the IL-1, IL-33, and IL-36 receptors. Using a novel anti-IL1RAP-blocking antibody, we investigated the role of IL1RAP in atherosclerosis.

METHODS AND RESULTS

Single-cell RNA sequencing data from human atherosclerotic plaques revealed the expression of IL1RAP and several IL1RAP-related cytokines and receptors, including IL1B and IL33. Histological analysis showed the presence of IL1RAP in both the plaque and adventitia, and flow cytometry of murine atherosclerotic aortas revealed IL1RAP expression on plaque leucocytes, including neutrophils and macrophages. High-cholesterol diet fed apolipoprotein E-deficient (Apoe-/-) mice were treated with a novel non-depleting IL1RAP-blocking antibody or isotype control for the last 6 weeks of diet. IL1RAP blockade in mice resulted in a 20% reduction in subvalvular plaque size and limited the accumulation of neutrophils and monocytes/macrophages in plaques and of T cells in adventitia, compared with control mice. Indicative of reduced plaque inflammation, the expression of several genes related to leucocyte recruitment, including Cxcl1 and Cxcl2, was reduced in brachiocephalic arteries of anti-IL1RAP-treated mice, and the expression of these chemokines in human plaques was mainly restricted to CD68+ myeloid cells. Furthermore, in vitro studies demonstrated that IL-1, IL-33, and IL-36 induced CXCL1 release from both macrophages and fibroblasts, which could be mitigated by IL1RAP blockade.

CONCLUSION

Limiting IL1RAP-dependent cytokine signalling pathways in atherosclerotic mice reduces plaque burden and plaque inflammation, potentially by limiting plaque chemokine production.

Different expression levels of interleukin-36 in asthma phenotypes

Interleukin (IL)-36 family is closely associated with inflammation and consists of IL-36α, IL-36β, IL-36γ, and IL-36Ra. The role of IL-36 in the context of asthma and asthmatic phenotypes is not well characterized. We examined the sputum IL-36 levels in patients with different asthma phenotypes in order to unravel the mechanism of IL-36 in different asthma phenotypes. Our objective was to investigate the induced sputum IL-36α, IL-36β, IL-36γ, and IL-36Ra concentrations in patients with mild asthma, and to analyze the relationship of these markers with lung function and other cytokines in patients with different asthma phenotypes. Induced sputum samples were collected from patients with mild controlled asthma (n = 62, 27 males, age 54.77 ± 15.49) and healthy non-asthmatic controls (n = 16, 10 males, age 54.25 ± 14.60). Inflammatory cell counts in sputum were determined. The concentrations of IL-36 and other cytokines in the sputum supernatant were measured by ELISA and Cytometric Bead Array. This is the first study to report the differential expression of different isoforms of IL-36 in different asthma phenotypes. IL-36α and IL-36β concentrations were significantly higher in the asthma group (P = 0.003 and 0.031), while IL-36Ra concentrations were significantly lower (P < 0.001) compared to healthy non-asthmatic controls. Sputum IL-36α and IL-36β concentrations in the neutrophilic asthma group were significantly higher than those in paucigranulocytic asthma (n = 24) and eosinophilic asthma groups (n = 23). IL-36α and IL-36β showed positive correlation with sputum neutrophils and total cell count (R = 0.689, P < 0.01; R = 0.304, P = 0.008; R = 0.689, P < 0.042; R = 0.253, P = 0.026). In conclusion, IL-36α and IL-36β may contribute to asthma airway inflammation by promoting neutrophil recruitment in airways. Our study provides insights into the inflammatory pathways of neutrophilic asthma and identifies potential therapeutic target.

Paediatric pustulotic arthro-osteitis patient with an IL36RN variant, heterozygous c.115+6T>C, who was successfully treated with tonsillectomy: A case report and literature review

Pustulotic arthro-osteitis (PAO) is an infrequent condition, with its manifestation in children being even rare. Some reports propose an association between genetic variants and the onset of PAO. Currently, no definitive treatment protocol exists for paediatric patients with PAO. In this study, we present the paediatric case of PAO with an IL36RN variant who was successfully treated with tonsillectomy.

IL-36 signaling pathway dysregulation in Crimean-Congo hemorrhagic fever virus patients: A potential therapeutic avenue

Crimean-Congo hemorrhagic fever (CCHF) is a severe viral disease. The scientific literature is growing, emphasizing the significance of the interleukin (IL)-36 family in the proinflammatory signaling pathway. However, to date, no research has explored the potential of IL-36 family members as biomarkers in CCHF. This study aims to bridge this gap by evaluating IL-36α, IL-36β, and IL-36γ levels in CCHF patients and healthy controls and investigating their association with disease severity and prognosis. Sixty confirmed CCHF patients and 29 healthy controls were enrolled in this case-control study. Serum levels of IL-36α, IL-36β, and IL-36γ were measured using enzyme-linked immunosorbent assays. Significantly higher levels of IL-36α and IL-36β were observed in CCHF patients compared to healthy controls (p < 0.05). However, no statistically significant changes were found in IL-36γ levels between the two groups. Among the CCHF patients, those who did not survive exhibited significantly elevated IL-36α and IL-36γ levels compared to survivors (p < 0.01). Positive correlations were identified between IL-36α and IL-36γ levels with activated partial thromboplastin time, and D-dimer (p < 0.01). Conversely, platelet levels showed a negative correlation with IL-36α and IL-36γ levels (p < 0.01). The increased levels of IL-36α, IL-36β, and IL-36γ in patients indicate their participation in proinflammatory reactions in CCHF patients. Understanding the role of IL-36 family members in CCHF pathogenesis could offer valuable insights into disease progression and facilitate the development of targeted therapeutic strategies.

Elevated serum IL-36γ levels in patients with ankylosing spondylitis and its association with disease activity

Ankylosing spondylitis (AS) is a chronic autoimmune disease. The purpose of this study was to investigate the levels of serum IL-36γ in AS patients and their association with AS. The study enrolled 131 subjects, including 45 with active AS, 46 with inactive AS, and 40 healthy controls (HCs). The basic clinical information of each participant was obtained through physical examination and relevant clinical medical records. Serum IL-36γ levels were detected through an enzyme-linked immunosorbent assay. Serum IL-36γ levels in the active AS group were significantly higher than those in the HC group (94.72 vs. 65.76 pg/mL, P = 0.0087). The serum IL-36γ concentration in the inactive AS group was increased as compared to that in the HC group (100.90 vs. 65.76 pg/mL, P = 0.0138). Correlation analysis indicated that serum IL-36γ was positively correlated with glutamyl transferase in the active AS group (P = 0.0172), while serum IL-36γ was positively correlated with uric acid in the inactive AS group (P = 0.0151). The area under the curve (AUC) for IL-36γ was 0.6824 (P = 0.0009), and the AUC for IL-36γ combined with the erythrocyte sedimentation rate and C-reactive protein levels was 0.8102 (P < 0.0001), according to receiver operating characteristic curve analysis. This study found that serum IL-36γ levels were elevated in AS patients and correlated with disease activity. Our results suggest that IL-36γ may be involved in the progression of AS disease and is a potential biomarker for AS.

Current management of generalized pustular psoriasis

Generalized pustular psoriasis (GPP) is a rare subset of psoriasis involving episodes of sterile pustules accompanied by inflammation and, often, systemic involvement. The inflammatory nature of GPP has potential for severe multisystem complications including high-output cardiac failure, infections, digestive system issues, and disfiguring or lethal acute flare episodes. The disease tends to have higher prevalence in females and Asians. The IL-1/IL-36 inflammatory pathway is a critical facet of GPP's pathology. Genetic mutations that are associated with GPP include modifications of Interleukin 36 Receptor Antagonist (IL36RN), Caspase Recruitment Domain Family Member 14 (CARD14), Adaptor Related Protein Complex 1 Subunit Sigma 3 (AP1S3), Myeloperoxidase (MPO) and Serpin Peptidase Inhibitor Clade A Member 3 (SERPINA3) genes. Treatment guidelines for GPP are not well-entrenched. Currently, only one GPP-specific treatment, the interleukin-36 receptor antagonist (IL-36Ra) spesolimab, has been approved for use in the United States. Additional anti-IL-36 pathway therapies are currently being developed. Other treatment options include other biologic therapies such as IL-17 inhibitors, IL-23 inhibitors and TNFα inhibitors. Non-biologic therapeutic options include retinoids, cyclosporine and methotrexate. Treatment options differ throughout the world; most countries utilize retinoids, cyclosporine and methotrexate as first-line non-biologic options. China and United Kingdom have no GPP-specific biologic therapies approved for use, while several biologic therapies are approved for use in Japan. This review aims to serve as an update on the current global management of GPP while also including relevant aspects of disease pathogenesis, diagnosis, clinical presentation, histopathology, aetiology and epidemiology.

Genetics of Generalized Pustular Psoriasis: Current Understanding and Implications for Future Therapeutics

Psoriasis is a chronic inflammatory skin disease characterized by the appearance of clearly demarcated erythematous and scaly plaques. It can be divided into various types, including plaque, nail, guttate, inverse, and pustular psoriasis. Plaque psoriasis is the most commonly occurring type, though there is another rare but severe pustular autoinflammatory skin disease called generalized pustular psoriasis (GPP), which manifests with acute episodes of pustulation and systemic symptoms. Though the etiopathogenesis of psoriasis is not yet fully understood, a growing body of literature has demonstrated that both genetic and environmental factors play a role. The discovery of genetic mutations associated with GPP has shed light on our comprehension of the mechanisms of the disease, promoting the development of targeted therapies. This review will summarize genetic determinants as known and provide an update on the current and potential treatments for GPP. The pathogenesis and clinical presentation of the disease are also included for a comprehensive discussion.

New insights on IL‑36 in intestinal inflammation and colorectal cancer (Review)

Interleukin (IL)-36 is a member of the IL-1 superfamily, which includes three receptor agonists and one antagonist and exhibits a familial feature of inflammatory regulation. Distributed among various tissues, such as the skin, lung, gut and joints, the mechanism of IL-36 has been most completely investigated in the skin and has been used in clinical treatment of generalized pustular psoriasis. Meanwhile, the role of IL-36 in the intestine has also been under scrutiny and has been shown to be involved in the regulation of various intestinal diseases. Inflammatory bowel disease and colorectal cancer are the most predominant inflammatory and neoplastic diseases of the intestine, and multiple studies have identified a complex role for IL-36 in both of them. Indeed, inhibiting IL-36 signaling is currently regarded as a promising therapeutic approach. Therefore, the present review briefly describes the composition and expression of IL-36 and focuses on the role of IL-36 in intestinal inflammation and colorectal cancer. The targeted therapies that are currently being developed for the IL-36 receptor are also discussed.

Autoimmune Neuroinflammatory Diseases: Role of Interleukins

Autoimmune neuroinflammatory diseases are a group of disorders resulting from abnormal immune responses in the nervous system, causing inflammation and tissue damage. The interleukin (IL) family of cytokines, especially IL-1, IL-6, and IL-17, plays a critical role in the pathogenesis of these diseases. IL-1 is involved in the activation of immune cells, production of pro-inflammatory cytokines, and promotion of blood-brain barrier breakdown. IL-6 is essential for the differentiation of T cells into Th17 cells and has been implicated in the initiation and progression of neuroinflammation. IL-17 is a potent pro-inflammatory cytokine produced by Th17 cells that plays a crucial role in recruiting immune cells to sites of inflammation. This review summarizes the current understanding of the roles of different interleukins in autoimmune neuroinflammatory diseases, including multiple sclerosis, amyotrophic lateral sclerosis, Alzheimer's disease, neuromyelitis optica, and autoimmune encephalitis, and discusses the potential of targeting ILs as a therapeutic strategy against these diseases. We also highlight the need for further research to better understand the roles of ILs in autoimmune neuroinflammatory diseases and to identify new targets for treating these debilitating diseases.

Evaluation of serum Interleukin 36 in Iraqi patients with Rheumatoid arthritis

Rheumatoid arthritis is a worldwide inflammatory chronic autoimmune disease with varying severity. Due to no definitive cure for this disease, current therapies aim to decrease the pain and slow further damage. The interleukin (IL)‐36 cytokine was little known for its role in rheumatoid arthritis; this research aimed to evaluate the serum IL36 levels in RA patients compared to healthy controls. This study included 80 patients with rheumatoid arthritis registered at the Rheumatology Clinic in Baghdad teaching hospital. The patients were divided into three groups based on the treatments received. Group 1 included patients treated with biological therapy (etanercept, adalimumab), Group2 patients with non-biological treatment (methotrexate hydroxychloroquine and prednisone), Group3 patients without any treatment and compared with Group 4 healthy control group. Patients is all groups were assessed for their serum IL-36 concentration; the mean IL-36 serum level was significantly higher in three groups of RA patients which include the group of patients treated with biological therapy (Enbrel (etanercept) and Humira (adalimumab) means were (1132.41±475.2,), and group of non-biological therapy patients (Methotrexate hydroxychloroquine and prednisone) (G2) means was 553.95±307, than patients' group without any treatment (G3) means was 1044.01±575.3 compared to the control (341.38±113.1) p-value> 0.00001. The patient's age and BMI were not significantly different between three groups of patient Rheumatoid arthritis. Parameters for this disease also were tested which include RF, CRP, ESR, anti-CCP and disease activity score-28 (DAS 28), there were significant differences when compared with the control group. IL-36 serum level was significantly higher in three groups of rheumatoid arthritis than those in controls, and when compared between three patients groups there was less concentration in the non-biological therapy treatment group means was 553.95±307 than in the rest of the patient groups,biology tratment, without any treatment, means were (1132.41±475.2, 1044.01±575.3) respectively. This study found that Rheumatoid arthritis patients' serum IL36 levels increased, where a non-biologic therapies reduced this cytokine. IL-36's pathogenic involvement in Rheumatoid arthritis needs more study. Keywords: Rheumatoid arthritis, IL-36, IL-1,C‐reactive protein, RF, ESR and anti-CCP.

Preparative isolation of maltol glycoside from Dianthus superbus and its anti-inflammatory activity in vitro

Dianthus superbus is a traditional Chinese medicine that is commonly utilized as a treatment for inflammation, pain, and immunological conditions. In this study, an anti-inflammatory maltol glycoside derived from Dianthus superbus was isolated for the first time via medium and high-pressure liquid chromatography, and at the same time, the in vitro anti-inflammatory activity of this maltol glycoside was preliminarily explored. Initially, crude samples of Dianthus superbus were preprocessed via MCI GEL® CHP20P and Spherical C18 medium-pressure chromatography, under the guidance of evaluation of in vitro anti-inflammatory activity. Fr44 was found to be the target fraction, and it was further isolated via two-dimensional reversed-phase/hydrophilic interaction liquid chromatography, yielding > 95% pure and was identified as tunicoside B. MTT assay, nitric oxide and nitric oxide synthase were used to evaluate the effects of tunicoside B on murine macrophage Raw264.7 by nitric oxide synthase assay kit, molecular docking, and western blotting. The results showed that tunicoside B did not affect the viability of cells and exhibited significant anti-inflammatory activity. As far as we know, this is the first report of tunicoside B from Dianthus superbus and the first study on the anti-inflammatory activity of tunicoside B. More importantly, the approach established in this study is expected to provide a theoretical basis for the separation and pharmacological activity study of maltol glycosides from other natural products.

Tunicoside B was isolated via medium-pressure chromatography and 2D reversed-phase/hydrophilic interaction liquid chromatography. Tunicoside B did not affect the viability of cells in vivo, and exhibited significant anti-inflammatory activity.

Proteomic Analysis of Tears and Conjunctival Cells Collected with Schirmer Strips Using timsTOF Pro: Preanalytical Considerations

This study aimed to investigate the human proteome profile of samples collected from whole (W) Schirmer strips (ScS) and their two parts—the bulb (B) and the rest of the strip (R)—with a comprehensive proteomic approach using a trapped ion mobility mass spectrometer, the timsTOF Pro. Eight ScS were collected from two healthy subjects at four different visits to be separated into three batches, i.e., 4W, 4B, and 4R. In total, 1582 proteins were identified in the W, B, and R batches. Among all identified proteins, binding proteins (43.4%) and those with catalytic activity (42.2%) constituted more than 80% of the molecular functions. The most represented biological processes were cellular processes (31.2%), metabolic processes (20.8%), and biological regulation (13.1%). Enzymes were the most represented protein class (41%), consisting mainly of hydrolases (47.5%), oxidoreductases (22.1%), and transferases (16.7%). The bulb (B), which is in contact with the conjunctiva, might collect both tear and cell proteins and therefore promote the identification of more proteins. Processing B and R separately before mass spectrometry (MS) analysis, combined with the high data acquisition speed and the addition of ion-mobility-based separation in the timsTOF Pro, can bring a new dimension to biomarker investigations of a limited sample such as tear fluid.