TGF-β is a multifunctional set of peptides that controls proliferation, differentiation, and other functions in many cell types. TGF-β acts synergistically with TGFA in inducing transformation. It also acts as a negative autocrinegrowth factor. Dysregulation of TGF-β activation and signaling may result in apoptosis. Many cells synthesize TGF-β and almost all of them have specific receptors for this peptide. TGF-β1, TGF-β2, and TGF-β3 all function through the same receptor signaling systems.[3]
TGF-β1 plays an important role in controlling the immune system, and shows different activities on different types of cell, or cells at different developmental stages. Most immune cells (or leukocytes) secrete TGF-β1.[6]
T cells
Some T cells (e.g. regulatory T cells) release TGF-β1 to inhibit the actions of other T cells. Interleukin 1- and interleukin 2-dependent proliferation of activated T cells,[7][8] and the activation of quiescent helper T cells and cytotoxic T cells is prevented by the activity of TGF-β1.[9][10] Similarly, TGF-β1 can inhibit the secretion and activity of many other cytokines including interferon-γ, tumor necrosis factor-alpha (TNF-α) and various interleukins. It can also decrease the expression levels of cytokine receptors, such as the IL-2 receptor to down-regulate the activity of immune cells. However, TGF-β1 can also increase the expression of certain cytokines in T cells and promote their proliferation, particularly if the cells are immature.[6]
B cells
TGF-β1 has similar effects on B cells that also vary according to the differentiation state of the cell. It inhibits proliferation and stimulates apoptosis of B cells,[11] and plays a role in controlling the expression of antibody, transferrin and MHC class II proteins on immature and mature B cells.[6][11]
Myeloid cells
The effects of TGF-β1 on macrophages and monocytes is predominantly suppressive; this cytokine can inhibit the proliferation of these cells and prevent their production of reactive oxygen (e.g. superoxide (O2−)) and nitrogen (e.g. nitric oxide (NO)) intermediates. However, as with other cell types, TGF-β1 can also have the opposite effect on cells of myeloid origin. For example, TGF-β1 acts as a chemoattractant, directing an immune response to some pathogens; macrophages and monocytes respond to low levels of TGF-β1 in a chemotactic manner. Furthermore, the expression of monocytic cytokines (including interleukin-1(IL-1)-alpha, IL-1-beta, and TNF-α),[10] and phagocytic killing by macrophages can be increased by the action of TGF-β1.[6]
↑Vaughn SP, Broussard S, Hall CR, Scott A, Blanton SH, Milunsky JM, Hecht JT (May 2000). "Confirmation of the mapping of the Camurati-Englemann locus to 19q13. 2 and refinement to a 3.2-cM region". Genomics. 66 (1): 119–21. doi:10.1006/geno.2000.6192. PMID10843814.
↑Assoian RK, Komoriya A, Meyers CA, Miller DM, Sporn MB (1983). "Transforming growth factor-beta in human platelets. Identification of a major storage site, purification, and characterization". J. Biol. Chem. 258 (11): 7155–60. PMID6602130.
↑Derynck R, Jarrett JA, Chen EY, Eaton DH, Bell JR, Assoian RK, Roberts AB, Sporn MB, Goeddel DV (1985). "Human transforming growth factor-beta complementary DNA sequence and expression in normal and transformed cells". Nature. 316 (6030): 701–5. doi:10.1038/316701a0. PMID3861940.
↑Wahl SM, Hunt DA, Wong HL, Dougherty S, McCartney-Francis N, Wahl LM, Ellingsworth L, Schmidt JA, Hall G, Roberts AB (1988). "Transforming growth factor-beta is a potent immunosuppressive agent that inhibits IL-1-dependent lymphocyte proliferation". J. Immunol. 140 (9): 3026–32. PMID3129508.
↑Tiemessen MM, Kunzmann S, Schmidt-Weber CB, Garssen J, Bruijnzeel-Koomen CA, Knol EF, van Hoffen E (2003). "Transforming growth factor-beta inhibits human antigen-specific CD4+ T cell proliferation without modulating the cytokine response". Int. Immunol. 15 (12): 1495–504. doi:10.1093/intimm/dxg147. PMID14645158.
↑Gilbert KM, Thoman M, Bauche K, Pham T, Weigle WO (1997). "Transforming growth factor-beta 1 induces antigen-specific unresponsiveness in naive T cells". Immunol. Invest. 26 (4): 459–72. doi:10.3109/08820139709022702. PMID9246566.
↑ 11.011.1Lebman DA, Edmiston JS (1999). "The role of TGF-beta in growth, differentiation, and maturation of B lymphocytes". Microbes Infect. 1 (15): 1297–304. doi:10.1016/S1286-4579(99)00254-3. PMID10611758.
↑Dong Y, Tang L, Letterio JJ, Benveniste EN (July 2001). "The Smad3 protein is involved in TGF-beta inhibition of class II transactivator and class II MHC expression". Journal of Immunology. 167 (1): 311–9. doi:10.4049/jimmunol.167.1.311. PMID11418665.
↑Schönherr E, Broszat M, Brandan E, Bruckner P, Kresse H (July 1998). "Decorin core protein fragment Leu155-Val260 interacts with TGF-beta but does not compete for decorin binding to type I collagen". Arch. Biochem. Biophys. 355 (2): 241–8. doi:10.1006/abbi.1998.0720. PMID9675033.
↑Takeuchi Y, Kodama Y, Matsumoto T (Dec 1994). "Bone matrix decorin binds transforming growth factor-beta and enhances its bioactivity". J. Biol. Chem. 269 (51): 32634–8. PMID7798269.
↑Choy L, Derynck R (November 1998). "The type II transforming growth factor (TGF)-beta receptor-interacting protein TRIP-1 acts as a modulator of the TGF-beta response". J. Biol. Chem. 273 (47): 31455–62. doi:10.1074/jbc.273.47.31455. PMID9813058.
↑Ebner R, Chen RH, Lawler S, Zioncheck T, Derynck R (November 1993). "Determination of type I receptor specificity by the type II receptors for TGF-beta or activin". Science. 262 (5135): 900–2. doi:10.1126/science.8235612. PMID8235612.
↑McGonigle S, Beall MJ, Feeney EL, Pearce EJ (February 2001). "Conserved role for 14-3-3epsilon downstream of type I TGFbeta receptors". FEBS Lett. 490 (1–2): 65–9. doi:10.1016/s0014-5793(01)02133-0. PMID11172812.
Munger JS, Harpel JG, Gleizes PE, Mazzieri R, Nunes I, Rifkin DB (1997). "Latent transforming growth factor-beta: structural features and mechanisms of activation". Kidney Int. 51 (5): 1376–82. doi:10.1038/ki.1997.188. PMID9150447.
Iozzo RV (1999). "The biology of the small leucine-rich proteoglycans. Functional network of interactive proteins". J. Biol. Chem. 274 (27): 18843–6. doi:10.1074/jbc.274.27.18843. PMID10383378.
Reinhold D, Wrenger S, Kähne T, Ansorge S (1999). "HIV-1 Tat: immunosuppression via TGF-beta1 induction". Immunol. Today. 20 (8): 384–5. doi:10.1016/S0167-5699(99)01497-8. PMID10431160.
Yamada Y (2001). "Association of polymorphisms of the transforming growth factor-beta1 gene with genetic susceptibility to osteoporosis". Pharmacogenetics. 11 (9): 765–71. doi:10.1097/00008571-200112000-00004. PMID11740340.
Chen W, Wahl SM (2002). TGF-beta: receptors, signaling pathways and autoimmunity. Curr. Dir. Autoimmun. Current Directions in Autoimmunity. 5. pp. 62–91. doi:10.1159/000060548. ISBN978-3-8055-7308-5. PMID11826761.
Marone M, Bonanno G, Rutella S, Leone G, Scambia G, Pierelli L (2002). "Survival and cell cycle control in early hematopoiesis: role of bcl-2, and the cyclin dependent kinase inhibitors P27 and P21". Leuk. Lymphoma. 43 (1): 51–7. doi:10.1080/10428190210195. PMID11908736.
Schnaper HW, Hayashida T, Hubchak SC, Poncelet AC (2003). "TGF-beta signal transduction and mesangial cell fibrogenesis". Am. J. Physiol. Renal Physiol. 284 (2): F243–52. doi:10.1152/ajprenal.00300.2002. PMID12529270.
Grainger DJ (2004). "Transforming growth factor beta and atherosclerosis: so far, so good for the protective cytokine hypothesis". Arterioscler. Thromb. Vasc. Biol. 24 (3): 399–404. doi:10.1161/01.ATV.0000114567.76772.33. PMID14699019.
McGowan TA, Zhu Y, Sharma K (2004). "Transforming growth factor-beta: a clinical target for the treatment of diabetic nephropathy". Curr. Diab. Rep. 4 (6): 447–54. doi:10.1007/s11892-004-0055-z. PMID15539010.
Sheppard D (2005). "Integrin-mediated activation of latent transforming growth factor beta". Cancer Metastasis Rev. 24 (3): 395–402. doi:10.1007/s10555-005-5131-6. PMID16258727.
