EAF2 mediates germinal centre B-cell apoptosis to suppress excessive immune responses and prevent autoimmunity

Regulated apoptosis of germinal centre (GC) B cells is critical for normal humoral immune responses. ELL-associated factor 2 (EAF2) regulates transcription elongation and has been shown to be an androgen-responsive potential tumour suppressor in prostate by inducing apoptosis. Here we show that EAF2 is selectively upregulated in GC B cells among various immune cell types and promotes apoptosis of GC B cells both in vitro and in vivo. EAF2 deficiency results in enlarged GCs and elevated antibody production during a T-dependent immune response. After immunization with type II collagen, mice lacking EAF2 produce high levels of collagen-specific autoantibodies and rapidly develop severe arthritis. Moreover, the mutant mice spontaneously produce anti-dsDNA, rheumatoid factor and anti-nuclear antibodies as they age. These results demonstrate that EAF2-mediated apoptosis in GC B cells limits excessive humoral immune responses and is important for maintaining self-tolerance.

[1]  S. Korsmeyer,et al.  Review Cell Death: Critical Control Points Another Line of Evidence for the Importance of Caspases in Cell Death Came From , 2022 .

[2]  D. Tarlinton,et al.  Through a glass less darkly: apoptosis and the germinal center response to antigen , 2012, Immunological reviews.

[3]  A. Parwani,et al.  Development of a Reactive Stroma Associated with Prostatic Intraepithelial Neoplasia in EAF2 Deficient Mice , 2013, PloS one.

[4]  P. Gaffney,et al.  Variants within MECP2, a key transcription regulator, are associated with increased susceptibility to lupus and differential gene expression in patients with systemic lupus erythematosus. , 2009, Arthritis and rheumatism.

[5]  T. Winkler,et al.  The role of somatic hypermutation in the generation of pathogenic antibodies in SLE , 2013, Autoimmunity.

[6]  Jon W. Huss,et al.  BioGPS: an extensible and customizable portal for querying and organizing gene annotation resources , 2009, Genome Biology.

[7]  Edward F. Rosloniec,et al.  Collagen‐Induced Arthritis , 1996, Current protocols in immunology.

[8]  A. Strasser,et al.  Regulation of memory B-cell survival by the BH3-only protein Puma. , 2011, Blood.

[9]  Stefan P. Glaser,et al.  Mcl-1 Is Essential for Germinal Center Formation and B Cell Memory , 2010, Science.

[10]  G. Kelsoe,et al.  In situ studies of the primary immune response to (4-hydroxy-3- nitrophenyl)acetyl. I. The architecture and dynamics of responding cell populations , 1991, The Journal of experimental medicine.

[11]  P. Polak,et al.  ELL-associated factor 2 (EAF2), a functional homolog of EAF1 with alternative ELL binding properties. , 2003, Blood.

[12]  Thomas L. Rothstein,et al.  The role of clonal selection and somatic mutation in autoimmunity , 1987, Nature.

[13]  A. Strasser,et al.  Bcl‐2 and Fas/APO‐1 regulate distinct pathways to lymphocyte apoptosis. , 1995, The EMBO journal.

[14]  Y. Takahashi,et al.  Fas is required for clonal selection in germinal centers and the subsequent establishment of the memory B cell repertoire. , 2001, Immunity.

[15]  K. Rajewsky,et al.  Fas receptor expression in germinal-center B cells is essential for T and B lymphocyte homeostasis. , 2008, Immunity.

[16]  Dan Wang,et al.  Pirin down‐regulates the EAF2/U19 protein and alleviates its growth inhibition in prostate cancer cells , 2014, The Prostate.

[17]  K. Shokat,et al.  Antigen-induced B-cell death and elimination during germinal-centre immune responses , 1995, Nature.

[18]  A. Strasser.  The role of BH3-only proteins in the immune system , 2005, Nature Reviews Immunology.

[19]  T. Behrens,et al.  Relaxed Negative Selection in Germinal Centers and Impaired Affinity Maturation in bcl-x L Transgenic Mice , 1999, The Journal of experimental medicine.

[20]  A. Strasser,et al.  The Role of Bim, a Proapoptotic BH3‐Only Member of the Bcl‐2 Family, in Cell‐Death Control , 2000, Annals of the New York Academy of Sciences.

[21]  A. Shilatifard,et al.  ELL-associated factors 1 and 2 are positive regulators of RNA polymerase II elongation factor ELL. , 2005, Proceedings of the National Academy of Sciences of the United States of America.

[22]  M. Oropallo,et al.  Germinal center reaction: antigen affinity and presentation explain it all. , 2014, Trends in immunology.

[23]  B. Diamond,et al.  Pathogenic autoantibodies are routinely generated during the response to foreign antigen: a paradigm for autoimmune disease. , 1996, Proceedings of the National Academy of Sciences of the United States of America.

[24]  R. V. van Lier,et al.  BH3-only protein Noxa regulates apoptosis in activated B cells and controls high-affinity antibody formation. , 2012, Blood.

[25]  M. Radic,et al.  Genetic and structural evidence for antigen selection of anti-DNA antibodies. , 1994, Annual review of immunology.

[26]  K. Rajewsky,et al.  Bcl-2 increases memory B cell recruitment but does not perturb selection in germinal centers. , 1994, Immunity.

[27]  P. Polak,et al.  EAF1, a novel ELL-associated factor that is delocalized by expression of the MLL-ELL fusion protein. , 2001, Blood.

[28]  Michel C. Nussenzweig,et al.  Clonal selection in the germinal centre by regulated proliferation and hypermutation , 2014, Nature.

[29]  M. Neuberger,et al.  Rapid methods for the analysis of immunoglobulin gene hypermutation: application to transgenic and gene targeted mice. , 1997, Nucleic acids research.

[30]  Kenneth G. C. Smith,et al.  Soluble antigen can cause enhanced apoptosis of germinal-centre B cells , 1995, Nature.

[31]  G. Kelsoe,et al.  In situ studies of the primary immune response to (4-hydroxy-3- nitrophenyl)acetyl. IV. Affinity-dependent, antigen-driven B cell apoptosis in germinal centers as a mechanism for maintaining self- tolerance , 1995, The Journal of experimental medicine.

[32]  D. Calado,et al.  Germinal Centers , 2017, Methods in Molecular Biology.

[33]  R. Brink.  The imperfect control of self-reactive germinal center B cells. , 2014, Current opinion in immunology.

[34]  T. Manser,et al.  Cutting Edge: Germinal Centers Can Be Induced in the Absence of T Cells1 , 2001, The Journal of Immunology.

[35]  T. Watanabe,et al.  Altered antigen receptor signaling and impaired Fas-mediated apoptosis of B cells in Lyn-deficient mice , 1996, The Journal of experimental medicine.

[36]  Ximing J. Yang,et al.  U19/Eaf2 knockout causes lung adenocarcinoma, B-cell lymphoma, hepatocellular carcinoma and prostatic intraepithelial neoplasia , 2008, Oncogene.

[37]  X. Cai,et al.  Genes regulated by androgen in the rat ventral prostate. , 1997, Proceedings of the National Academy of Sciences of the United States of America.

[38]  A. Strasser,et al.  Proapoptotic BH3-only protein Bim is essential for developmentally programmed death of germinal center-derived memory B cells and antibody-forming cells. , 2007, Blood.

[39]  F. Delbos,et al.  Mismatch repair deficiency interferes with the accumulation of mutations in chronically stimulated B cells and not with the hypermutation process. , 1998, Immunity.

[40]  Acknowledgements , 1992, Experimental Gerontology.

[41]  L. Wysocki,et al.  Somatic mutagenesis in autoimmunity , 2013, Autoimmunity.

[42]  A. Strasser,et al.  The BCL-2 protein family: opposing activities that mediate cell death , 2008, Nature Reviews Molecular Cell Biology.

[43]  R. Brink,et al.  Elimination of germinal-center-derived self-reactive B cells is governed by the location and concentration of self-antigen. , 2012, Immunity.

[44]  J. Forrester,et al.  Peanut lectin binding properties of germinal centers of mouse lymphoid tissue , 1980, Nature.

[45]  T. Kurosaki,et al.  A Role for Lysosomal-Associated Protein Transmembrane 5 in the Negative Regulation of Surface B Cell Receptor Levels and B Cell Activation , 2010, The Journal of Immunology.

[46]  Kenneth G. C. Smith,et al.  bcl-2 Transgene Expression Inhibits Apoptosis in the Germinal Center and Reveals Differences in the Selection of Memory B Cells and Bone Marrow Antibody-Forming Cells , 2000, The Journal of experimental medicine.

[47]  F. Hanaoka,et al.  DNA polymerase η is a limiting factor for A:T mutations in Ig genes and contributes to antibody affinity maturation , 2008, European journal of immunology.

[48]  Zhou Wang,et al.  Suppression of prostate tumor growth by U19, a novel testosterone-regulated apoptosis inducer. , 2003, Cancer research.

[49]  A. Strasser,et al.  Proapoptotic Bcl-2 relative Bim required for certain apoptotic responses, leukocyte homeostasis, and to preclude autoimmunity. , 1999, Science.

[50]  D. Vaux,et al.  Enforced BCL2 expression in B-lymphoid cells prolongs antibody responses and elicits autoimmune disease. , 1991, Proceedings of the National Academy of Sciences of the United States of America.

[51]  S. Ben‐Sasson,et al.  Identification of programmed cell death in situ via specific labeling of nuclear DNA fragmentation , 1992, The Journal of cell biology.

[52]  G. Nossal,et al.  FAS is highly expressed in the germinal center but is not required for regulation of the B-cell response to antigen. , 1995, Proceedings of the National Academy of Sciences of the United States of America.