The role of the deubiquitinating enzymes Cyld and A20 in B cell lymphomagenesis
African, American and Oceania Studies
Final Report Abstract
In this grand application we investigated how enforced NF-κB activation driven by B-cell specific deletion of the deubiquitinating enzymes, CYLD and A20, affect B-cell lymphomagenesis. It is known that a tightly regulated NF-κB pathway is crucial for B- cell development and homeostasis. Aberrant activation of this pathway has been shown to be involved in chronic lymphocytic leukemia (B-CLL), the most common leukemia in the Western world. CLL is characterized by the accumulation of small CD5+ B lymphocytes with a mature phenotype. Different signaling pathways, such as the nuclear factor kappa B (NF-κB), show constitutive activity in CLL cells; however, the underlying mechanisms leading to this disease remain largely unknown and were a subject of this grand application. To prevent persistent NF-κB activation, a tight control is required. Whereas linkage with polyubiquitin chains via lysine-48 results in proteasomal degradation of target proteins, lysine-63-linked polyubiquitin chains have non-degradative, regulatory functions and serve in the recruitment of various kinase complex platforms. Ubiquitination is a reversible process mediated by deubiquitinating enzymes, such as CYLD and A20, which prevent persistent NF-κB activation by deubiquitinating target proteins. CYLD acts as a negative regulator of the NF-κB pathway by removing lysine-63-linked ubiquitin chains from its target proteins thereby regulating diverse biological functions, such as immune-cell-development, activation, inflammation and tumorigenesis. Previously, we have identified a short isoform of CYLD, termed sCYLD, encoded by a natural splice variant of the Cyld mRNA that retains deubiquitinating activity but lacks the domain for TRAF2 and NEMO, required to dampen NF-κB activation. Mice lacking (FL)-Cyld but overexpressing sCYLD demonstrate enlarged lymphoid organs resulting from an expanded B2 B-cell compartment. Similar to CYLD, A20 (TNFAIP3) is capable of removing lysine-63, but also lysine-48-linked ubiquitin chains from its target proteins. Others and we could show that B-cell-specific deletion of A20 results in sustained canonical NF-κB activity and predisposes mice to autoimmunity. During the time of this application we could show that mice with accelerated activation of canonical NF-κB activation, driven by sCYLD overexpression in B cells, spontaneously develop a CD5+ B-cell lymphoproliferative disorder while mice with a complete lack of CYLD did not develop signs of this disease, indicating a sCYLD dependent phenotype. Further enhancement of canonical NF-κB activation, achieved by additional B-cell-specific deletion of A20, reinforced clonal accumulation of CD5+ B cells, ultimately leading to a late-onset CLL-like disease, recapitulating hallmarks of human CLL. Mice with A20 deletion specifically in B cells (A20BKO mice) were used to achieve sustained activation of canonical NF-κB signaling; in CLL patients, this activation occurs through other mechanisms, including BCR or microenvironmental activation. We further found that a substantial number of CLL patient samples express sCYLD, strongly implicating a role for it in human B-CLL. We propose that our new CLL-like mouse model represents an appropriate tool for studying ubiquitination-driven canonical NF-κB activation in CLL. Thus, inhibition of alternative splicing of this negative regulator is essential for preventing NF-κB-driven clonal CD5+ B-cell expansion and ultimately CLL-like disease.
Publications
- Elevated levels of Bcl-3 inhibits Treg development and function resulting in spontaneous colitis. Nat Commun. 2017 Apr 28;8:15069
Reißig S, Tang Y, Nikolaev A, Gerlach K, Wolf C, Davari K, Gallus C, Masri J, Mufazalov IA, Neurath MF, Wunderlich FT, Schattenberg JM, Galle PR, Weigmann B, Waisman A, Glasmacher E, Hövelmeyer N
(See online at https://dx.doi.org/10.1038/ncomms15069) - Mutated cylindromatosis gene affects the functional state of dendritic cells. Eur J Immunol. 2010 Oct;40(10):2848-57
Bros M, Dexheimer N, Besche V, Masri J, Trojandt S, Hövelmeyer N, Reissig S, Massoumi R, Grabbe S, Waisman A, Reske-Kunz AB
(See online at https://dx.doi.org/10.1002/eji.200939285) - Smad7 in T cells drives T helper 1 responses in multiple sclerosis and experimental autoimmune encephalomyelitis. Brain. 2010 Apr;133(Pt 4):1067-81
Kleiter I, Song J, Lukas D, Hasan M, Neumann B, Croxford AL, Pedré X, Hövelmeyer N, Yogev N, Mildner A, Prinz M, Wiese E, Reifenberg K, Bittner S, Wiendl H, Steinman L, Becker C, Bogdahn U, Neurath MF, Steinbrecher A, Waisman A
(See online at https://dx.doi.org/10.1093/brain/awq039) - A20 deficiency in B cells enhances B-cell proliferation and results in the development of autoantibodies. Eur J Immunol. 2011 Mar;41(3):595-601
Hövelmeyer N, Reissig S, Xuan NT, Adams-Quack P, Lukas D, Nikolaev A, Schlüter D, Waisman A
(See online at https://dx.doi.org/10.1002/eji.201041313) - Down-regulation of CYLD as a trigger for NF-κB activation and a mechanism of apoptotic resistance in hepatocellular carcinoma cells. Int J Oncol. 2011 Jan;38(1):121-31
Urbanik T, Köhler BC, Boger RJ, Wörns MA, Heeger S, Otto G, Hövelmeyer N, Galle PR, Schuchmann M, Waisman A, Schulze-Bergkamen H
(See online at https://doi.org/10.3892/ijo_00000831) - Liver specific deletion of CYLDexon7/8 induces severe biliary damage, fibrosis and increases hepatocarcinogenesis in mice. J Hepatol. 2012 Nov;57(5):995-1003
Urbanik T, Boger RJ, Longerich T, Becker K, Ehrenberg KR, Hövelmeyer N, Hahn M, Schuchmann M, Jäger D, Waisman A, Wörns MA, Schulze-Bergkamen H
(See online at https://doi.org/10.1016/j.jhep.2012.06.017) - The tumor suppressor CYLD controls the function of murine regulatory T cells. J Immunol. 2012 Nov 15;189(10):4770-6
Reissig S, Hövelmeyer N, Weigmann B, Nikolaev A, Kalt B, Wunderlich TF, Hahn M, Neurath MF, Waisman A
(See online at https://doi.org/10.4049/jimmunol.1201993) - Mechanisms of chronic JAK-STAT3-SOCS3 signaling in obesity. JAKSTAT. 2013 Apr 1;2(2):e23878
Wunderlich CM, Hövelmeyer N, Wunderlich FT
(See online at https://dx.doi.org/10.4161/jkst.23878) - CYLD deletion triggers nuclear factor-κB-signaling and increases cell death resistance in murine hepatocytes. World J Gastroenterol. 2014 Dec 7;20(45):17049-64
Urbanik T, Koehler BC, Wolpert L, Elßner C, Scherr AL, Longerich T, Kautz N, Welte S, Hövelmeyer N, Jäger D, Waisman A, Schulze-Bergkamen H
(See online at https://doi.org/10.3748/wjg.v20.i45.17049) - Overexpression of Bcl-3 inhibits the development of marginal zone B cells. Eur J Immunol. 2014 Feb;44(2):545-52
Hövelmeyer N, Wörns MA, Reissig S, Adams-Quack P, Leclaire J, Hahn M, Wörtge S, Nikolaev A, Galle PR, Waisman A
(See online at https://doi.org/10.1002/eji.201343655) - The deubiquitinating enzyme CYLD regulates the differentiation and maturation of thymic medullary epithelial cells. Immunol Cell Biol. 2015 Jul;93(6):558-66
Reissig S, Hövelmeyer N, Tang Y, Weih D, Nikolaev A, Riemann M, Weih F, Waisman A
(See online at https://doi.org/10.1038/icb.2014.122) - BAX inhibitor-1 is a Ca(2+) channel critically important for immune cell function and survival. Cell Death Differ. 2016 Feb;23(2):358-68
Lisak D, Schacht T, Gawlitza A, Albrecht P, Aktas O, Koop B, Gliem M, Hofstetter HH, Zanger K, Bultynck G, Parys JB, De Smedt H, Kindler T, Adams-Quack P, Hahn M, Waisman A, Reed JC, Hövelmeyer N, Methner A
(See online at https://doi.org/10.1038/cdd.2015.115) - NF-κB-inducing kinase is essential for B-cell maintenance in mice. Eur J Immunol. 2016 Mar;46(3):732-41
Hahn M, Macht A, Waisman A, Hövelmeyer N
(See online at https://doi.org/10.1002/eji.201546081) - Aberrant splicing of the tumor suppressor CYLD promotes the development of chronic lymphocytic leukemia via sustained NF-κB signaling. Leukemia. 2017 Jun 1
Hahn M, Bürckert JP, Luttenberger CA, Klebow S, Hess M, Al-Maarri M, Vogt M, Reißig S, Hallek M, Wienecke-Baldacchino A, Buch T, Muller CP, Pallasch CP, Wunderlich FT, Waisman A, Hövelmeyer N
(See online at https://doi.org/10.1038/leu.2017.168)
