Interleukin-1 beta (IL-1β) also known as leukocytic pyrogen, leukocytic endogenous mediator, mononuclear cell factor, lymphocyte activating factor and other names, is a cytokineprotein that in humans is encoded by the IL1Bgene.[5][6][7][8] There are two genes for interleukin-1 (IL-1): IL-1 alpha and IL-1 beta (this gene). IL-1β precursor is cleaved by cytosolic caspase 1 (interleukin 1 beta convertase) to form mature IL-1β.
The fever-producing property of human leukocytic pyrogen (interleukin 1) was purified by Dinarello in 1977 with a specific activity of 10–20 nanograms/kg.[9] In 1979, Dinarello reported that purified human leukocytic pyrogen was the same molecule that was described by Igal Gery in 1972.[10][11][12] He named it lymphocyte-activating factor (LAF) because it was a lymphocyte mitogen. It was not until 1984 that interleukin 1 was discovered to consist of two distinct proteins, now called interleukin-1 alpha and interleukin-1 beta.[6]
IL-1β is a member of the interleukin 1 family of cytokines. This cytokine is produced by activated macrophages, monocytes, and a subset of dendritic cells known as slanDC,[13] as a proprotein, which is proteolytically processed to its active form by caspase 1 (CASP1/ICE). This cytokine is an important mediator of the inflammatory response, and is involved in a variety of cellular activities, including cell proliferation, differentiation, and apoptosis. The induction of cyclooxygenase-2 (PTGS2/COX2) by this cytokine in the central nervous system (CNS) is found to contribute to inflammatory pain hypersensitivity. This gene and eight other interleukin 1 family genes form a cytokine gene cluster on chromosome 2.[14]
IL-1β, in combination with IL-23, induced expression of IL-17, IL-21 and IL-22 by γδ T cells. This induction of expression is in the absence of additional signals. That suggests IL-1β is involved in modulation of autoimmune inflammation [15]
Different inflammasome complex — cytosolic molecular complex — have been described. Inflammasomes recognize danger signals and activate proinflammatory process and production of IL-1β and IL-18. NLRP3 (contains three domain: pyrin domain, a nucleotide-binding domain and a leucine-rich repeat) type of inflammasome is activated by various stimuli and there are documented several diseases connected to NLRP3 activation like type 2 diabetes mellitus, Alzheimer's disease, obesity and atherosclerosis.[16]
Before cleavage by caspase 1, pro-IL-1β has a molecular weight of 37 kDa.[13] The molecular weight of the proteolytically processed IL-1β is 17.5 kDa. IL-1β has the following amino acid sequence:
The presence of IL-1β has been also found in patients with multiple sclerosis (a chronic autoimmune disease of the central nervous system). However, it is not known exactly which cells produce IL-1β. Treatment of multiple sclerosis with glatiramer acetate or natalizumab has also been shown to reduce the presence of IL-1β or its receptor.[22]
Several types of inflammasomes are suggested to play role in tumorgenesis due to their immunomodulatory properties, modulation of gut microbiota, differentiation and apoptosis. Over-expression of IL-1β caused by inflammasome may result in carcinogenesis. Some data suggest that NLRP3 inflammasome polymorphisms is connected to malignancies such as colon cancer and melanoma. It was reported that IL-1β secretion was elevated in the lung adenocarcinoma cell line A549. It has also been shown in another study that IL-1β, together with IL-8, plays an important role in chemoresistance of malignant pleural mesothelioma by inducing expression of transmembrane transporters.[23] Another study showed that inhibition of inflammasome and IL-1β expression decreased development of cancer cells in melanoma.[24]
Furthermore, it has been found that in breast cancer cells, IL-1β activates p38 and p42/22 MAPK pathways which ultimately lead to the secretion of the RANK/RANKL inhibitor osteoprotegerin. Higher osteoprotegerin and IL-1β levels are a characteristic of breast cancer cells with a higher metastatic potential.[25]
The human immunodeficiency virus (HIV) infects cells of the immune system, such as macrophages, dendritic cells, and CD4+ T helper cells (TH). The latter can be infected by the virus in various ways with different fates depending on the state of activation of the T helper cell.[13]
Firstly, TH cells can die of viral lysis due to an active infection that produces enough virions to kill the cell. Secondly, CD4+ T cells can be infected by the virus but instead of producing more viral particles, the cell enters a latent phase. In this period, the T helper cells looks identical from the outside but any stressor could lead to the renewed production of HIV and its propagation to new immune cells. Lastly, the TH cell can become abortively infected, where the virus gets detected inside the cell and a programmed cell-death, known as pyroptosis, kills the infected cell. Pyroptosis is mediated via caspase-1 and is characterized by cell lysis and the secretion of IL-1β causing inflammation and attraction of more immune cells. This can create a cycle of CD4+ T cells getting abortively infect with HIV, dying of pyroptosis, new T helper cells arriving to the site of inflammation where they get infected again. The results is the depletion of T helper cells. Even though, levels of IL-1β in blood are not majorly different between HIV positive and negative individuals, studies have shown elevated levels of IL-1β of lymphatic tissue in HIV-infected individuals.[13]
In fact, the gut-associated lymphoid tissue (GALT) has a high density of immune cells as the gut is an interface between symbiotic gut microbes that should remain with the host and pathogenic bacteria that should not gain access into the circulatory system. If HIV-infection leads to the secretion of IL-1βin monocytes and macrophages, it causes inflammation of this area. The mucosal epithelial layer responds to this by producing less or altering the tight junction proteins which makes it easier for pathogenic microbes to move into the lamina propria. Here, the pathogens can further activate local immune cells and amplify the inflammatory response.[13]
It has been shown that IL-1 family plays important role in inflammation in many degenerative diseases, such as age-related macular degeneration, diabetic retinopathy and retinitis pigmentosa. Significantly increased protein level of IL-1β has been found in the vitreous of diabetic retinopathy patient. The role of IL-1β has been investigated for potential therapeutic target for treatment of diabetic retinopathy. However, systemic using of canakinumab did not have a significant effect. The role of IL-1β in age-related macular degeneration has not been proven in patient, but in many animal models and in vitro studies it has been demonstrated the role of IL-1β in retinal pigmented epithelial cells and photoreceptor cells damage. NLRP3 inflammasome activate caspase-1 which catalyze cleavage of inactive cytosolic precursor pro-IL-1β to its mature form IL-1β. Retinal pigmented epithelial cells forms blood retinal barrier in human retina which is important for retinal metabolic activity, integrity and inhibition of immune cells infiltration. It has been shown that human retinal pigmented epithelial cells can secrete IL-1 β in exposure to oxidative stress. The inflammatory reaction leads to damage of retinal cells and infiltration of cells of the immune system. The inflammatory process including NLRP3 upregulation is one of the causes of age-related macular degeneration and other retinal diseases that lead to vision loss.[26][27][28] Additionally, it has been shown that caspase-1 is upregulated in the retina of diabetic patients, causing a higher production of IL-1β and subsequent death of retinal neurons.[29]
Studies in mice on experimental autoimmune encephalomyelitis (EAE), a model for multiple sclerosis (MS) research, have found that blocking IL-1β could make the animals resistant to EAE. IL-1β led to the production of an antigen-specific pro-inflammatory subset of T helper cells (TH17). In combination with other cytokines, interleukin-1β can upregulate the production of the cytokine GM-CSF which is correlated to neuroinflammation. Detailed mechanisms on this front are yet to be elucidated.[29]
IL-1β has also been observed in elevated levels of the cerebrospinal fluid and brain tissues of Alzheimer patients. The amyloid-β plaques, that are characteristic of Alzheimer disease, are damage-associated molecular patterns (DAMPs) that are recognized by pattern recognition receptors (PRRs) and lead to the activation of microglia. Consequently, microglia release interleukin-1β among other cytokines. Nevertheless, the significance of IL-1β in Alzheimer disease and the onset of neuroinflammation still remains largely unknown.[29]
Lastly, in vitro studies have shown that IL-1β causes an increase in mitochondrial glutaminase activity. In response, there is excessive glutamate secretion which has a neurotoxic effect.[29]
Anakinra is a recombinant and slightly modified version of the human interleukin 1 receptor antagonist protein. Anakinra blocks the biologic activity of IL-1 alpha and beta by competitively inhibiting IL-1 binding to the interleukin type 1 receptor (IL-1RI), which is expressed in a wide variety of tissues and organs. Anakinra is marketed as Kineret and is approved in the US for treatment of RA, NOMID, DIRA.
Because many authors of scientific manuscripts make the minor error of using a homoglyph, sharp s (ß), instead of beta (β), mentions of "IL-1ß" [sic] often become "IL-1ss" [sic] upon automated transcoding (because ß transcodes to ss). This is why so many mentions of the latter appear in web search results.
^ ab"Catabolin" is the name given by Jeremy Saklatvala for IL-1 alpha. March CJ, Mosley B, Larsen A, Cerretti DP, Braedt G, Price V, et al. (1985). "Cloning, sequence and expression of two distinct human interleukin-1 complementary DNAs". Nature. 315 (6021): 641–647. Bibcode:1985Natur.315..641M. doi:10.1038/315641a0. PMID2989698. S2CID4240002.
^Gery I, Handschumacher RE (March 1974). "Potentiation of the T lymphocyte response to mitogens. III. Properties of the mediator(s) from adherent cells". Cellular Immunology. 11 (1–3): 162–169. doi:10.1016/0008-8749(74)90016-1. PMID4549027.
^ abcdeYaseen MM, Abuharfeil NM, Darmani H (January 2023). "The role of IL-1β during human immunodeficiency virus type 1 infection". Reviews in Medical Virology. 33 (1): e2400. doi:10.1002/rmv.2400. PMID36209388. S2CID252762935.
^Pelegrín P, García-Castillo J, Mulero V, Meseguer J (October 2001). "Interleukin-1beta isolated from a marine fish reveals up-regulated expression in macrophages following activation with lipopolysaccharide and lymphokines". Cytokine. 16 (2): 67–72. doi:10.1006/cyto.2001.0949. PMID11683587.
^Scapigliati G, Buonocore F, Bird S, Zou J, Pelegrin P, Falasca C, et al. (November 2001). "Phylogeny of cytokines: molecular cloning and expression analysis of sea bass Dicentrarchus labrax interleukin-1beta". Fish & Shellfish Immunology. 11 (8): 711–726. doi:10.1006/fsim.2001.0347. PMID11759041.
^Pelegrín P, Chaves-Pozo E, Mulero V, Meseguer J (March 2004). "Production and mechanism of secretion of interleukin-1beta from the marine fish gilthead seabream". Developmental and Comparative Immunology. 28 (3): 229–237. doi:10.1016/j.dci.2003.08.002. PMID14642889.
Smirnova MG, Kiselev SL, Gnuchev NV, Birchall JP, Pearson JP (2003). "Role of the pro-inflammatory cytokines tumor necrosis factor-alpha, interleukin-1 beta, interleukin-6 and interleukin-8 in the pathogenesis of the otitis media with effusion". European Cytokine Network. 13 (2): 161–172. PMID12101072.
Chakravorty M, Ghosh A, Choudhury A, Santra A, Hembrum J, Roychoudhury S (February 2004). "Ethnic differences in allele distribution for the IL8 and IL1B genes in populations from eastern India". Human Biology. 76 (1): 153–159. doi:10.1353/hub.2004.0016. PMID15222686. S2CID2816300.
Joseph AM, Kumar M, Mitra D (January 2005). "Nef: "necessary and enforcing factor" in HIV infection". Current HIV Research. 3 (1): 87–94. doi:10.2174/1570162052773013. PMID15638726.
Maruyama Y, Stenvinkel P, Lindholm B (2005). "Role of interleukin-1beta in the development of malnutrition in chronic renal failure patients". Blood Purification. 23 (4): 275–281. doi:10.1159/000086012. PMID15925866. S2CID72570361.
Milosevic V, Kopecka J, Salaroglio IC, Libener R, Napoli F, Izzo S, et al. (January 2020). "Wnt/IL-1β/IL-8 autocrine circuitries control chemoresistance in mesothelioma initiating cells by inducing ABCB5". International Journal of Cancer. 146 (1): 192–207. doi:10.1002/ijc.32419. hdl:2318/1711962. PMID31107974. S2CID160014053.
Copeland KF (December 2005). "Modulation of HIV-1 transcription by cytokines and chemokines". Mini Reviews in Medicinal Chemistry. 5 (12): 1093–1101. doi:10.2174/138955705774933383. PMID16375755.
1hib: THE STRUCTURE OF AN INTERLEUKIN-1 BETA MUTANT WITH REDUCED BIOACTIVITY SHOWS MULTIPLE SUBTLE CHANGES IN CONFORMATION THAT AFFECT PROTEIN-PROTEIN RECOGNITION
1i1b: CRYSTAL STRUCTURE OF RECOMBINANT HUMAN INTERLEUKIN-1BETA AT 2.0 ANGSTROMS RESOLUTION
1iob: INTERLEUKIN-1 BETA FROM JOINT X-RAY AND NMR REFINEMENT
1itb: TYPE-1 INTERLEUKIN-1 RECEPTOR COMPLEXED WITH INTERLEUKIN-1 BETA
1l2h: Crystal structure of Interleukin 1-beta F42W/W120F mutant
1s0l: Interleukin 1 beta mutant F42W
1t4q: Interleukin 1 beta F101W
1too: Interleukin 1B Mutant F146W
1tp0: Triple mutation in interleukin 1 beta cavity:replacement of phenylalanines with tryptophan.
1twe: INTERLEUKIN 1 BETA MUTANT F101Y
1twm: Interleukin-1 Beta Mutant F146Y
21bi: INTERLEUKIN-1 BETA (IL-1 BETA) (MUTANT WITH CYS 71 REPLACED BY ALA) (C71A)
2i1b: CRYSTALLOGRAPHIC REFINEMENT OF INTERLEUKIN-1 BETA AT 2.0 ANGSTROMS RESOLUTION
2nvh: Determination of Solvent Content in Cavities in Interleukin-1 Using Experimentally-Phased Electron Density
31bi: INTERLEUKIN-1 BETA (IL-1 BETA) (MUTANT WITH CYS 71 REPLACED BY SER) (C71S)
41bi: INTERLEUKIN-1 BETA (IL-1 BETA) (MUTANT WITH CYS 8 REPLACED BY ALA (C8A)
4i1b: FUNCTIONAL IMPLICATIONS OF INTERLEUKIN-1BETA BASED ON THE THREE-DIMENSIONAL STRUCTURE
5i1b: A COMPARISON OF THE HIGH RESOLUTION STRUCTURES OF HUMAN AND MURINE INTERLEUKIN-1B
6i1b: HIGH-RESOLUTION THREE-DIMENSIONAL STRUCTURE OF INTERLEUKIN-1 BETA IN SOLUTION BY THREE-AND FOUR-DIMENSIONAL NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY
7i1b: HIGH-RESOLUTION THREE-DIMENSIONAL STRUCTURE OF INTERLEUKIN-1 BETA IN SOLUTION BY THREE-AND FOUR-DIMENSIONAL NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY