Epigenetic regulation of IFN-g during Mycobacterium tuberculosis infection is mediated by Tle4, Blimp1 and Methylation at the -53 CpG site

GUADALUPE INÉS ALVAREZ; RODRIGO HERNÁNDEZ DEL PINO; ANGELA BARBERO; ROSA MUSELLA; DOMINGO PALMERO; VERÓNICA GARCÍA; VIRGINIA PASQUINELLI

Buenos Aires

Congreso; LXIII Reunión Anual de Sociedad Argentina de Inmunología, IV Reunión de la Sociedad Latinoamericana de Inmunodeficiencias (LASID) y II Congreso Franco-Argentino de Inmunología (FAIC); 2015

Sociedad Argentina de Inmunología. Sociedad Latinoamericana de Inmunodeficiencias

IFN-g is a crucial cytokine during protectiveimmunity against Mycobacteriumtuberculosis (Mtb) infection. Elucidation of the mechanisms that regulates IFN-g will enhance our knowledge about Tuberculosis (TB) pathogenesis. IFNG expression could be regulated by several epigenetics mechanisms including histone modifications and DNA methylation. Thetranscriptional repressor complex Transducin-like enhancer of split 4 (Tle4) and B lymphocyte-induced maturation protein (Blimp1) binds to DNA and recruits histonedeacetylases (HDACs). Blimp1 and TLE4 silence IFNG in anergic TH1 cells. Methylationof -53 CpG IFNG site is crucial during TH1 differentiation. Therefore, we evaluateTle4/Blimp1 and -53 CpG methylation in the immune response to Mtb.   Peripheral blood mononuclear cells (PBMCs) fromTuberculosis patients (PTB) and Healthy Donors (HD) were stimulated with sonicatedMtb. In some experiments, HDCACs inhibitors (HDACSi) Trichostatin A (TSA), Sodium butyrate (NaB) and Entinostat (MS275) were used. IFN-g expression (determined by Real TimePCR) was negatively correlated with TLE4/Blimp1 expression. In PTB the higherfold increase of IFN-g was observed at 24h (233.856± 93.14 (X±SEM)),while TLE4/Blimp1showed the lowest values (1.034 ± 0.217/0.803 ± 0.125, respectively). Similar results were observedin HD at 48h. TSA and NaB inhibited IFNg production (ELISA), but induce apoptosis even at low concentrations. MS275 increase IFN-g productionat low concentration (Fold increase vs Mtb=426.82±162.49). -53 CpG methylation (bisulfitepyrosequencing) was associated with IFN-g production (pg/ml) in PTB DNA pools (66% X=2726.92 vs74% X=403.70). Recruitment of HDACS trough TLE4/Blimp1 and -53 CpG methylation of IFNG could negatively regulate IFN-g expression during Mtb infection.