C17orf99 | |||||||||||||||||||||||||||||||||||||||||||||||||||
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Aliases | C17orf99 , UNQ464, chromosome 17 open reading frame 99, IL-40, IL40, Interleukin 40 | ||||||||||||||||||||||||||||||||||||||||||||||||||
External IDs | MGI: 1924977; HomoloGene: 90660; GeneCards: C17orf99; OMA:C17orf99 - orthologs | ||||||||||||||||||||||||||||||||||||||||||||||||||
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Interleukin 40 (IL-40), also known with other name C17orf99, is a protein belonging to a group of cytokines called interleukins. It is encoded by a gene that does not belong to any cytokine superfamily. [5] This cytokine is produced primarily by human expression tissues such as bone marrow and fetal liver, and its expression can be also induced in peripheral B cells after activation. [6] IL-40 is involved in immunoglobulin A (IgA) production, and plays an important role in humoral immune responses and B cell homeostasis and development. [7] [8]
In October 2017, an article was published [9] concerning a previously uncharacterized gene C17orf99 (chromosome 17 open reading frame 99) which is localized on chromosome 17 (17q25.3). [10] This gene encodes a polypeptide chain with 265 amino acids long sequence (including a 20-aa signal peptide), which further determines the mature small secreted protein with predicted molecular weight of approximately 27 kDa.
Due to its unique sequence, IL-40 is not structurally related to any other cytokine family, suggesting that it has a distinct evolutionary history. Besides IL-40, there are few cytokines that also do not belong to any cytokine superfamily, namely: IL-32 and IL-34. [7]
Since this protein is primarily secreted after B cell activation, it was assumed that the gene product C17orf99 would affect the immune system, however, the precise effects require further investigation. Testing was conducted on mice with targeted chromosomal deletion. The novel cytokine that resulted from the study was designated IL-40 and is the most recent in a line of cytokines found.
Only mammalian genomes contain C17orf99, which is expressed by B cells that have been activated, however the expression profile of IL-40 is similar in two species (mouse and human) and is 72% conserved at the amino acid level between them. [9]
IL-40 has been found is crucial for humoral immune reactions, synthesis of IgA [11] and might be helpful for the growth of B cells, B cell maturation in the BM and in the periphery and their homeostasis. Importantly, human activated B cells and some B cell lymphomas express IL-40 as well. The major producing cells are B cells, bone marrow stroma cells.
IL-40 is associated with lactation and affects initiation of IgA production in the mammary gland. Through the interaction of mucosal immunity and microbiota, the composition of the gut microbiome in mice is also correlated with expression of cytokine IL-40.
Cytokines like IL-4 and TGF-1 can increase the amount of IL-40.
Latter findings imply that it might be related to pathophysiological and inflammatory aspects of diseases.
IL-40 cytokine may play a regulatory role in the pathogenesis of inflammatory diseases such as rheumatoid arthritis, ankylosing spondylitis, which is a common chronic inflammatory autoimmune rheumatic disorder, several cell lines of human diffuse large B cell lymphoma and also can play some role in autoimmune hepatitis as discriminating autoantigens. [6]
In a disorder called ankylosing spondylitis (AS), [12] it has been discovered to be connected with elevated circulating levels of pro-inflammatory cytokines and additionally, it has been revealed that anti-inflammatory cytokines are crucial for AS immunological homeostasis such as interleukin (IL)-1 family, in that it includes both pro-inflammatory (IL-1α, IL-1β, IL-18, IL-33, and IL-36) and anti-inflammatory (IL-37 and IL-38) cytokines. It has been revealed that IL-40 was significantly higher in AS patients than in controls, and it can be used as biomarker with other cytokines in serum of patients. [13] [14] [15]
Given the association of IL-40 with B cells homeostasis [16] and the crucial role of B cells in autoimmunity, [16] it only makes sense to focus on this cytokine during studies of rheumatoid arthritis or autoimmunity in general. Exploring IL-40 as a potential biomarker for earlier diagnosis of these diseases could lead to improvement in therapeutic outcomes. Additionally, there is potential to leverage IL-40 in therapeutic interventions. [17]
The expression of IL-40, an interleukin involved in immune regulation, has been found to be elevated in the synovial fluid of patients with rheumatoid arthritis. [16] RA is characterized by autoimmune reactions primarily targeting the synovial membrane, [18] making the synovial fluid a valuable medium for studying molecules that interact with or originate from this membrane. A comparison of IL-40 expression in synovial tissue between RA and osteoarthritis (OA) patients reveals significantly higher levels in RA patients, particularly within the inflammatory infiltrate. Within the synovial tissue of RA patients, IL-40 is observed to co-localize with various immune cells such as macrophages, B cells, T cells, and neutrophils. [16] Neutrophils, in particular, have been identified as a known source of IL-40 in the context of RA. [16]
In addition to its presence in the synovial fluid, IL-40 levels are elevated in the serum of RA patients compared to those with OA. However, the concentration of IL-40 is notably higher in the local inflammatory sites, specifically the RA synovial fluid, compared to levels of IL-40 in serum. [16] [17]
IL-40 in RA patients is correlated with disease activity and the levels of autoantibodies. [16] Furthermore, during the early stages of RA, IL-40 is elevated in the serum compared to healthy individuals. However, after three months of conventional therapy, IL-40 levels in the early stages of RA can be normalized. [17] Studies have shown that elevated IL-40 levels in RA decrease following B-cell depletion therapy, as demonstrated by the effects of rituximab on serum IL-40 after 16 and 24 weeks of therapy [16]
Serum levels of IL-40 in early RA correlate with the levels of autoantibodies and NETosis markers. These correlations become evident when neutrophils are stimulated to undergo NETosis or when they are exposed to inflammatory factors like IL-1β, IL-8, tumor necrosis factor, or lipopolysaccharide. Following the induction of NETosis or exposure to inflammatory cytokines, neutrophils showed enhanced secretion of IL-40, indicating their potential involvement in the heightened IL-40 levels observed among early RA patients. [16] [17]
For ankylosing spondylitis (AS) IL-40 has a potential relevance as a biomarker. The levels of IL-40 are significantly higher in the serum of AS patients in comparison with healthy controls (HCs). IL-40 might have excellent diagnostic performance, suggesting its potential as a biomarker for AS susceptibility. [19] IL-40 levels were upregulated in serum of AS patients regardless of age, disease duration, disease activity or HLA-B27. [19] This observation is relevant to AS since it is suggested that the gut microbiota plays a role in the development of the condition. [19]
Recently, an implication of IL-40 in the pathogenesis of primary Sjögren syndrome (pSS) and pSS-associated lymphoma was investigated. Overexpression of IL-40 was demonstrated in the salivary glands of patients with pSS, particularly in lymphocytic infiltrates and ductal epithelial cells, when compared to non-Sjögren's syndrome patients (nSS). IL-40 was also up-regulated in patients with pSS-associated lymphoma in comparison to nSS. [20] The expression of IL-40 was associated with the degree of inflammatory infiltrate in the salivary glands, [20] which suggests a potential role of IL-40 in driving the inflammatory response. The tissue expression of IL-40 correlated with the expression levels of IL-4 and TGF-β. [20]
In comparison to nSS patients, CD19+ B lymphocytes were the major source of IL-40 in the lymphatic-infiltrated glands of pSS patients.
[20] Furthermore, pSS patients had an expanded population of CD19+IL-40+ B cells in peripheral blood mononuclear cells compared to HCs. [20] In addition, IL-40 was elevated in the serum of patients with pSS compared to nSS and significantly correlated with the disease activity score EULAR Sjögren's Syndrome Disease Activity Index. (citace) Moreover, a positive association was found between IL-40 levels and anti-SSA (Sjögren Syndrome related antigen A) and immunoglobulin (Ig) levels. [20] In in vitro conditions, recombinant IL-40 significantly enhanced the expression of proinflacmmatory cytokines in T cells and IFN-γ production by B cells, both isolated from pSS patients. [20] Moreover, recombinant IL-40 stimulated NETosis in neutrophils from pSS patients. [20]
Rheumatoid arthritis (RA) is a long-term autoimmune disorder that primarily affects joints. It typically results in warm, swollen, and painful joints. Pain and stiffness often worsen following rest. Most commonly, the wrist and hands are involved, with the same joints typically involved on both sides of the body. The disease may also affect other parts of the body, including skin, eyes, lungs, heart, nerves, and blood. This may result in a low red blood cell count, inflammation around the lungs, and inflammation around the heart. Fever and low energy may also be present. Often, symptoms come on gradually over weeks to months.
In immunology, autoimmunity is the system of immune responses of an organism against its own healthy cells, tissues and other normal body constituents. Any disease resulting from this type of immune response is termed an "autoimmune disease". Prominent examples include celiac disease, diabetes mellitus type 1, Henoch–Schönlein purpura, systemic lupus erythematosus, Sjögren syndrome, eosinophilic granulomatosis with polyangiitis, Hashimoto's thyroiditis, Graves' disease, idiopathic thrombocytopenic purpura, Addison's disease, rheumatoid arthritis, ankylosing spondylitis, polymyositis, dermatomyositis, and multiple sclerosis. Autoimmune diseases are very often treated with steroids.
Immunosuppressive drugs, also known as immunosuppressive agents, immunosuppressants and antirejection medications, are drugs that inhibit or prevent the activity of the immune system.
Ankylosing spondylitis (AS) is a type of arthritis characterized by long-term inflammation of the joints of the spine, typically where the spine joins the pelvis. With AS, eye and bowel problems—as well as back pain—may occur. Joint mobility in the affected areas sometimes worsens over time. Ankylosing spondylitis is believed to involve a combination of genetic and environmental factors. More than 90% of people affected in the UK have a specific human leukocyte antigen known as the HLA-B27 antigen. The underlying mechanism is believed to be autoimmune or autoinflammatory. Diagnosis is based on symptoms with support from medical imaging and blood tests. AS is a type of seronegative spondyloarthropathy, meaning that tests show no presence of rheumatoid factor (RF) antibodies.
Granulocyte-macrophage colony-stimulating factor (GM-CSF), also known as colony-stimulating factor 2 (CSF2), is a monomeric glycoprotein secreted by macrophages, T cells, mast cells, natural killer cells, endothelial cells and fibroblasts that functions as a cytokine. The pharmaceutical analogs of naturally occurring GM-CSF are called sargramostim and molgramostim.
Felty's syndrome (FS), also called Felty syndrome, is a rare autoimmune disease characterized by the triad of rheumatoid arthritis, enlargement of the spleen and low neutrophil count. The condition is more common in those aged 50–70 years, specifically more prevalent in females than males, and more so in Caucasians than those of African descent. It is a deforming disease that causes many complications for the individual.
Interleukin-22 (IL-22) is a protein that in humans is encoded by the IL22 gene.
Interleukin 20 (IL20) is a protein that is in humans encoded by the IL20 gene which is located in close proximity to the IL-10 gene on the 1q32 chromosome. IL-20 is a part of an IL-20 subfamily which is a part of a larger IL-10 family.
Interleukin 19 (IL-19) is an immunosuppressive protein that belongs to the IL-10 cytokine subfamily.
Interleukin 17 receptor A, also known as IL17RA and CDw217, is a human gene.
Interleukin 20 receptors (IL20R) belong to the IL-10 family. IL20R are involved in both pro-inflammatory and anti-inflammatory immune response. There are two types of IL20R: Type I and Type II.
Interleukin-17A is a protein that in humans is encoded by the IL17A gene. In rodents, IL-17A used to be referred to as CTLA8, after the similarity with a viral gene.
Sir Marc Feldmann,, is an Australian-educated British immunologist. He is a professor at the University of Oxford and a senior research fellow at Somerville College, Oxford.
The Interleukin-1 family is a group of 11 cytokines that plays a central role in the regulation of immune and inflammatory responses to infections or sterile insults.
Secukinumab, sold under the brand name Cosentyx among others, is a human IgG1κ monoclonal antibody used for the treatment of psoriasis, ankylosing spondylitis, and psoriatic arthritis. It binds to the protein interleukin (IL)-17A and is marketed by Novartis.
Interleukin 36, or IL-36, is a group of cytokines in the IL-1 family with pro-inflammatory effects. The role of IL-36 in inflammatory diseases is under investigation.
Interleukin-38 (IL-38) is a member of the interleukin-1 (IL-1) family and the interleukin-36 (IL-36) subfamily. It is important for the inflammation and host defense. This cytokine is named IL-1F10 in humans and has similar three dimensional structure as IL-1 receptor antagonist (IL-1Ra). The organisation of IL-1F10 gene is conserved with other members of IL-1 family within chromosome 2q13. IL-38 is produced by mammalian cells may bind the IL-1 receptor type I. It is expressed in basal epithelia of skin, in proliferating B cells of the tonsil, in spleen and other tissues. This cytokine is playing important role in regulation of innate and adaptive immunity.
Interleukin 17F (IL-17F) is signaling protein that is in human is encoded by the IL17F gene and is considered a pro-inflammatory cytokine. This protein belongs to the interleukin 17 family and is mainly produced by the T helper 17 cells after their stimulation with interleukin 23. However, IL-17F can be also produced by a wide range of cell types, including innate immune cells and epithelial cells.
Epigenetics of autoimmune disorders is the role that epigenetics play in autoimmune diseases. Autoimmune disorders are a diverse class of diseases that share a common origin. These diseases originate when the immune system becomes dysregulated and mistakenly attacks healthy tissue rather than foreign invaders. These diseases are classified as either local or systemic based upon whether they affect a single body system or if they cause systemic damage.
Iain Blair McInnes is a Scottish rheumatologist, Vice Principal and Head of the College of Medical, Veterinary and Life Sciences, Muirhead Chair of Medicine and Versus Arthritis Professor of Rheumatology at the University of Glasgow. His research has focused on inflammatory diseases, particularly rheumatoid arthritis and psoriatic arthritis.