Tumor necrosis factor (TNF), formerly known as TNF-α, is a chemical messenger that mediates the immune system and induces inflammation.[5] TNF is produced primarily by activated macrophages, and induces inflammation by binding to its target receptors on other cells.[6] It is a member of the tumor necrosis factor superfamily, a family of transmembrane proteins that are immunocytokines, chemical messengers of the immune system.[7] Excessive production of TNF plays a critical role in several inflammatory diseases, and TNF-blocking drugs are often employed to treat these diseases.[8]
TNF is produced primarily by macrophages but is also produced in several other cell types, such as T cells, B cells, dendritic cells, and mast cells. It is produced rapidly in response to pathogens, cytokines, and environmental stressors, without dependence on the synthesis of other proteins.[9] TNF is initially produced as a type II transmembrane protein (tmTNF), which is then cleaved by TNF alpha converting enzyme (TACE) into a soluble form (sTNF) and secreted from the cell.[10] Three TNF molecules assemble together to form an active homotrimer, whereas individual TNF molecules are inert.[10]
When TNF binds to its target receptors, tumor necrosis factor receptor 1 (TNFR1) and tumor necrosis factor receptor 2 (TNFR2), a pathway of signals is triggered within the target cell, resulting in an inflammatory response. sTNF can only activate TNFR1, whereas tmTNF can activate both TNFR1 and TNFR2[6], as well as trigger inflammatory signaling pathways within its own cell.[11] TNF's effects on the immune system include the activation of white blood cells, blood coagulation, secretion of cytokines, and fever, among others.[5] TNF plays a role beyond the immune system, such as contributing to homeostasis in the central nervous system.[12]
Excessive production of TNF is a key factor in inflammatory disorders such as rheumatoid arthritis, psoriasis, and inflammatory bowel disease, and can be effectively treated by drugs that inhibit TNF from binding to its receptors.[8] TNF is also implicated in the pathology of other diseases including cancer, liver fibrosis, and Alzheimer's, although TNF inhibition has yet to show definitive benefits.[13] Due to the important and complex role of TNF in the immune system, the inhibition of TNF can lead to side effects such as increased risk of infections and new forms of autoimmunities.[14]
- ^ a b c ENSG00000230108, ENSG00000223952, ENSG00000204490, ENSG00000228321, ENSG00000232810, ENSG00000228849, ENSG00000206439 GRCh38: Ensembl release 89: ENSG00000228978, ENSG00000230108, ENSG00000223952, ENSG00000204490, ENSG00000228321, ENSG00000232810, ENSG00000228849, ENSG00000206439 – Ensembl, May 2017
- ^ a b c GRCm38: Ensembl release 89: ENSMUSG00000024401 – Ensembl, May 2017
- ^ "Human PubMed Reference:". National Center for Biotechnology Information, U.S. National Library of Medicine.
- ^ "Mouse PubMed Reference:". National Center for Biotechnology Information, U.S. National Library of Medicine.
- ^ a b Cite error: The named reference
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DeathByInflammationwas invoked but never defined (see the help page). - ^ Croft M, Siegel RM (March 2017). "Beyond TNF: TNF superfamily cytokines as targets for the treatment of rheumatic diseases". Nature Reviews Rheumatology. 13 (4): 217–233. doi:10.1038/nrrheum.2017.22. PMC 5486401. PMID 28275260.
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TNFOnCNSwas invoked but never defined (see the help page). - ^ Sethi JK, Hotamisligil GS (October 2021). "Metabolic Messengers: tumour necrosis factor". Nature Metabolism. 3 (10): 1302–1312. doi:10.1038/s42255-021-00470-z. PMID 34650277.
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