Suchergebnisse

[Background]: Age-associated changes in genomic DNA methylation have been primarily attributed to 5-methylcytosine (5mC). However, the recent discovery of 5-hydroxymethylcytosine (5hmC) suggests that this epigenetic mark might also play a role in the process. [Methods]: Here, we analyzed the genome-wide profile of 5hmc in mesenchymal stem cells (MSCs) obtained from bone-marrow donors, aged 2-89 years. [Results]: We identified 10,685 frequently hydroxymethylated CpG sites in MSCs that were, as in other cell types, significantly associated with low density CpG regions, introns, the histone posttranslational modification H3k4me1 and enhancers. Study of the age-associated changes to 5hmC identified 785 hyper- and 846 hypo-hydroxymethylated CpG sites in the MSCs obtained from older individuals. [Conclusions]: DNA hyper-hydroxymethylation in the advanced-age group was associated with loss of 5mC, which suggests that, at specific CpG sites, this epigenetic modification might play a role in DNA methylation changes during lifetime. Since bone-marrow MSCs have many clinical applications, and the fact that the epigenomic alterations in this cell type associated with aging identified in this study could have associated functional effects, the age of donors should be taken into account in clinical settings. ; This work has been financially supported by the Plan Nacional de I + D + I 2008–2011/2013–2016/FEDER (PI11/01728 to A.F.F.; PI12/01080 and PI15/00892 to M.F.F.; PI 12/0615 to J.A.R.; PI05/2217 and PI08/0029 to J.G-C); the ISCIII-Subdirección General de Evaluación y Fomento de la Investigación (Miguel Servet contract: CP11/00131 to A.F.F.); IUOPA (to G.F.B. and M.S); Fundacion Cientifica de la AECC (to R.G.U.); Fundación Ramón Areces (to M.F.F); and FICYT (to E.G.T., M.G.G and A.C.);the Madrid Regional Government (S-BIO-02042006 and S2010/BMD-2420 to J.G-C) and the Asturias Regional Government (GRUPIN14-052 to M.F.F.). The IUOPA is supported by the Obra Social Cajastur, Spain. ; Peer Reviewed

BACKGROUND: Age-associated changes in genomic DNA methylation have been primarily attributed to 5-methylcytosine (5mC). However, the recent discovery of 5-hydroxymethylcytosine (5hmC) suggests that this epigenetic mark might also play a role in the process. METHODS: Here, we analyzed the genome-wide profile of 5hmc in mesenchymal stem cells (MSCs) obtained from bone-marrow donors, aged 2-89 years. RESULTS: We identified 10,685 frequently hydroxymethylated CpG sites in MSCs that were, as in other cell types, significantly associated with low density CpG regions, introns, the histone posttranslational modification H3k4me1 and enhancers. Study of the age-associated changes to 5hmC identified 785 hyper- and 846 hypo-hydroxymethylated CpG sites in the MSCs obtained from older individuals. CONCLUSIONS: DNA hyper-hydroxymethylation in the advanced-age group was associated with loss of 5mC, which suggests that, at specific CpG sites, this epigenetic modification might play a role in DNA methylation changes during lifetime. Since bone-marrow MSCs have many clinical applications, and the fact that the epigenomic alterations in this cell type associated with aging identified in this study could have associated functional effects, the age of donors should be taken into account in clinical settings. ; This work has been financially supported by the Plan Nacional de I+D+I 2008–2011/2013–2016/FEDER (PI11/01728 to A.F.F.; PI12/01080 and PI15/00892 to M.F.F.; PI 12/0615 to J.A.R.; PI05/2217 and PI08/0029 to J.G‑C); the ISCIII‑Subdirección General de Evaluación y Fomento de la Investigación (Miguel Servet contract: CP11/00131 to A.F.F.); IUOPA (to G.F.B. and M.S); Fundacion Cientifica de la AECC (to R.G.U.); Fundación Ramón Areces (to M.F.F); and FICYT (to E.G.T., M.G.G and A.C.); the Madrid Regional Government (S‑BIO‑0204‑2006 and S2010/BMD‑2420 to J.G‑C) and the Asturias Regional Government (GRUPIN14‑052 to M.F.F.). The IUOPA is supported by the Obra Social Cajastur, Spain.

Glioblastoma multiforme (GBM) is the most common and aggressive type of brain tumor in adulthood. Epigenetic mechanisms are known to play a key role in GBM although the involvement of histone methyltransferase KMT5B and its mark H4K20me2 has remained largely unexplored. The present study shows that DNA hypermethylation and loss of DNA hydroxymethylation is associated with KMT5B downregulation and genome-wide reduction of H4K20me2 levels in a set of human GBM samples and cell lines as compared with non-tumoral specimens. Ectopic overexpression of KMT5B induced tumor suppressor-like features in vitro and in a mouse tumor xenograft model, as well as changes in the expression of several glioblastoma-related genes. H4K20me2 enrichment was found immediately upstream of the promoter regions of a subset of deregulated genes, thus suggesting a possible role for KMT5B in GBM through the epigenetic modulation of key target cancer genes. ; This research was funded by the Health Institute Carlos III (Plan Nacional de I+D+I) cofounding FEDER (PI15/00892 and PI18/01527 to MF and AF); the Government of the Principality of Asturias PCTI-Plan de Ciencia, Tecnología e Innovación de Asturias co-funding 2018–2022/FEDER (IDI/2018/146 to MF); AECC (PROYE18061FERN to MF); FGCSIC (0348_CIE_6_E to MF); Severo Ochoa Program BP17-165 to PS-O and BP17-114 to RP); the Ministry of Economy and Competitiveness of Spain (VL, Juan de la Cierva fellowship IJCI-2015-23316; JT, Juan de la Cierva fellowship FJCI-2015-26965); FICYT (AC and MG); FINBA-ISPA (VL); and IUOPA (VL and CM). The IUOPA is supported by the Obra Social Cajastur-Liberbank, Spain. ; Peer reviewed

Ten-eleven translocation (TET) enzymes are frequently deregulated in cancer, but the underlying molecular mechanisms are still poorly understood. Here we report that TET2 shows frequent epigenetic alterations in human glioblastoma including DNA hypermethylation and hypo-hydroxymethylation, as well as loss of histone acetylation. Ectopic overexpression of TET2 regulated neural differentiation in glioblastoma cell lines and impaired tumor growth. Our results suggest that epigenetic dysregulation of TET2 plays a role in human glioblastoma. ; This work has been financially supported by: the Plan Nacional de I+D+I 2013-2016/FEDER (PI15/00892 to M.F.F. and A.F.F.); the ISCIII-Subdirección General de Evaluación y Fomento de la Investigación, and the Plan Nacional de I+D+I 2008-2011/FEDER (CP11/00131 to A.F.F.); IUOPA (to G.F.B., M.I.S. and C.M.); the Fundación Científica de la AECC (to R.G.U.); FICYT (to M.G.G. and A.C.); and the Asturias Regional Government (GRUPIN14-052 to M.F.F.). A.F.F. is also supported from Ministerio de Economía y Competitividad and the European Regional Development Fund (FEDER), Programa Retos de la Sociedad 2015 (RTC-2015-3393-1). The IUOPA is supported by the Obra Social Cajastur-Liberbank, Spain. ; Peer Reviewed

In differentiated cells, aging is associated with hypermethylation of DNA regions enriched in repressive histone post-translational modifications. However, the chromatin marks associated with changes in DNA methylation in adult stem cells during lifetime are still largely unknown. Here, DNA methylation profiling of mesenchymal stem cells (MSCs) obtained from individuals aged 2 to 92 yr identified 18,735 hypermethylated and 45,407 hypomethylated CpG sites associated with aging. As in differentiated cells, hypermethylated sequences were enriched in chromatin repressive marks. Most importantly, hypomethylated CpG sites were strongly enriched in the active chromatin mark H3K4me1 in stem and differentiated cells, suggesting this is a cell type-independent chromatin signature of DNA hypomethylation during aging. Analysis of scedasticity showed that interindividual variability of DNA methylation increased during aging in MSCs and differentiated cells, providing a new avenue for the identification of DNA methylation changes over time. DNA methylation profiling of genetically identical individuals showed that both the tendency of DNA methylation changes and scedasticity depended on nongenetic as well as genetic factors. Our results indicate that the dynamics of DNA methylation during aging depend on a complex mixture of factors that include the DNA sequence, cell type, and chromatin context involved and that, depending on the locus, the changes can be modulated by genetic and/or external factors. ; We thank Ronnie Lendrum for manuscript preparation and Tim Triche Jr. for his invaluable advice. This work has been financially supported by the Plan Nacional de I+D+I 2008-2011/2013-2016/FEDER (PI11/01728 to A.F.F., PI 12/0615 to J.A.R., PI10/0449 to P.M., and PI11/0119 to C.B.); the ISCIII-Subdirección General de Evaluación y Fomento de la Investigación (Miguel Servet contracts CP11/00131 to A.F.F. and CP07/0059 to C.B.); the Spanish Ministry of Health (PS09/02454 and PI12/01080 to M.F.F.); the Spanish National Research Council (CSIC; 200820I172 to M.F.F.); IUOPA (to C.F. and G.F.B.); Fundacion Cientifica de la AECC (to R.G.U. and P.M.); Fundación Ramón Areces (to M.F.F.); and FICYT (to E.G.T.). J.G.-C. receives funding from the Fondo de Investigaciones Sanitarias (FIS; PI05/2217 and PI08/0029) and the Madrid Regional Government (S-BIO-0204-2006 and S2010/BMD-2420). J.A.R. receives funding from the Fondo de Investigaciones Sanitarias (ISCIII-FIS PI 12/0615). P.M. is also supported by MINECO (SAF2013/43065), ERANET E-Rare (PI112/03112), and Fundación Sandra Ibarra. P.M. also acknowledges support from Obra Social "La Caixa/Fundacio Josep Carreras." The IUOPA is supported by the Obra Social Cajastur, Spain. ; Sí

Histone H4 acetylation at Lysine 16 (H4K16ac) is a key epigenetic mark involved in gene regulation, DNA repair and chromatin remodeling, and though it is known to be essential for embryonic development, its role during adult life is still poorly understood. Here we show that this lysine is massively hyperacetylated in peripheral neutrophils. Genome-wide mapping of H4K16ac in terminally differentiated blood cells, along with functional experiments, supported a role for this histone post-translational modification in the regulation of cell differentiation and apoptosis in the hematopoietic system. Furthermore, in neutrophils, H4K16ac was enriched at specific DNA repeats. These DNA regions presented an accessible chromatin conformation and were associated with the cleavage sites that generate the 50 kb DNA fragments during the first stages of programmed cell death. Our results thus suggest that H4K16ac plays a dual role in myeloid cells as it not only regulates differentiation and apoptosis, but it also exhibits a non-canonical structural role in poising chromatin for cleavage at an early stage of neutrophil cell death. ; Plan Nacional de I+D+I co-funding FEDER [PI15/00892 and PI18/01527 to M.F.F. and A.F.F.; PI16/01318 and PI14/01244 to C.L.]; ISCIII-Subdireccion General de Evaluacion y Fomento de la Investigacion, and Plan Nacional de I+D+I 2008–2011/FEDER [CP11/00131 to A.F.F.]; IUOPA (to G.F.B. and M.I.S.); Fundacion Cientifica de la AECC (to R.G.U.); Ministry of Economy and Competitiveness Juan de la Cierva postdoctoral fellowships [FJCI-2015-26965 to J.R.T., IJCI-2015- 23316 to V.L.]; Fundacion Ramon Areces (to M.F.F); FICYT (to E.G.T., M.G.G., A.C.); Asturias Regional Government [GRUPIN14-052 to M.F.F.]; Gobierno del Principado de Asturias, PCTI-Plan de Ciencia, Tecnologia e Innovacion co-funding Fondos FEDER (grant number IDI/2018/146 to M.F.F. and IDI/2018/144 to C.L.); Deutsche Forschungsgemeinschaft (DFG) [SFB960 to A.V.G., R.D.]; European Research Council [CoG-2014-646903]; Spanish Ministry of Economy and Competitiveness [SAF-SAF2013-43065 to P.M.]; Asociacion Española Contra el Cancer [AECC-CI-2015]; FERO Foundation, and the ISCIII [PI14-01191 to C.B.]; P.M. acknowledges financial support from The Obra Social La Caixa Fundacio Josep Carreras and The Generalitat de Catalunya (SGR330). P.M. an investigator from the Spanish Cell Therapy cooperative network (TERCEL). The IUOPA is supported by the Obra Social Liberbank-Cajastur, Spain. Funding for open access charge: Plan Nacional de I+D+I co-funding FEDER [PI18/01527].