PPP2R2B hypermethylation causes acquired apoptosis deficiency in systemic autoimmune diseases
Iris K. Madera-Salcedo, Beatriz E. Sánchez-Hernández, Yevgeniya Svyryd, Marcela Esquivel-Velázquez, Noé Rodríguez-Rodríguez, María Isabel Trejo-Zambrano, H. Benjamín García-González, Gabriela Hernández-Molina, Osvaldo M. Mutchinick, Jorge Alcocer-Varela, Florencia Rosetti, José C. Crispín
Iris K. Madera-Salcedo, Beatriz E. Sánchez-Hernández, Yevgeniya Svyryd, Marcela Esquivel-Velázquez, Noé Rodríguez-Rodríguez, María Isabel Trejo-Zambrano, H. Benjamín García-González, Gabriela Hernández-Molina, Osvaldo M. Mutchinick, Jorge Alcocer-Varela, Florencia Rosetti, José C. Crispín
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Research Article Immunology

PPP2R2B hypermethylation causes acquired apoptosis deficiency in systemic autoimmune diseases

Abstract

Chronic inflammation causes target organ damage in patients with systemic autoimmune diseases. The factors that allow this protracted response are poorly understood. We analyzed the transcriptional regulation of PPP2R2B (B55β), a molecule necessary for the termination of the immune response, in patients with autoimmune diseases. Altered expression of B55β conditioned resistance to cytokine withdrawal–induced death (CWID) in patients with autoimmune diseases. The impaired upregulation of B55β was caused by inflammation-driven hypermethylation of specific cytosines located within a regulatory element of PPP2R2B preventing CCCTC-binding factor binding. This phenotype could be induced in healthy T cells by exposure to TNF-α. Our results reveal a gene whose expression is affected by an acquired defect, through an epigenetic mechanism, in the setting of systemic autoimmunity. Because failure to remove activated T cells through CWID could contribute to autoimmune pathology, this mechanism illustrates a vicious cycle through which autoimmune inflammation contributes to its own perpetuation.

Authors

Iris K. Madera-Salcedo, Beatriz E. Sánchez-Hernández, Yevgeniya Svyryd, Marcela Esquivel-Velázquez, Noé Rodríguez-Rodríguez, María Isabel Trejo-Zambrano, H. Benjamín García-González, Gabriela Hernández-Molina, Osvaldo M. Mutchinick, Jorge Alcocer-Varela, Florencia Rosetti, José C. Crispín

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Figure 7

TNF-α induces PPP2R2B methylation, abolishes B55β expression, and impairs CWID in healthy T cells.

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TNF-α induces PPP2R2B methylation, abolishes B55β expression, and impair...
(A) T cells from HDs were activated and expanded in the presence of IL-2 for 10 days. In addition to IL-2, at days 0, 2, 4, 6, and 8, the indicated cytokines (TNF-α, IFN-α, IL-6, IL-21, or IL-17) were added to the culture. At day 10, cells were counted, washed, and replated in the absence of IL-2 and proinflammatory cytokines. (B) Apoptosis (annexin V+ SYTOX Orange−) was quantified before (0 hours) and after IL-2 withdrawal (n = 3–6). *P < 0.05; **P < 0.01; 2-way ANOVA with Tukey’s multiple-comparisons test. (C) Expression of B55β was determined (qPCR) before and after (24 and 48 hours) IL-2 withdrawal. Results were normalized against ACTB (Ct) and then against cells expanded in the presence of IL-2 but in the absence of other cytokines (ΔΔCt). *P < 0.05; **P < 0.01; ***P < 0.001; 2-way ANOVA. (D) Methylation of the CpG dinucleotides from Amp 1 was determined by pyrosequencing in cells expanded in IL-2 (dotted line) and compared with the CpG DNA methylation of the same cells expanded in the presence of TNF-α or IL-21 (n = 8–11). *P < 0.05, paired two-tailed t test. (E) The relative change in methylation status of single CpG dinucleotides in response to TNF-α and IL-21 is shown (n = 8–11). *P < 0.05, paired two-tailed t test.