Cromatina, metabolisme i destí celular

  • Buschbeck_Group_Statue_11_2017
ICO - German Trias i Pujol

Office:        (+34) 93 557 2800 extn 4070
Laboratory: (+34) 93 557 2800 extn 4071

Josep Carreras Leukaemia Research Institute
Edifici IMPPC
Can Ruti CampusCtra de Can Ruti
Camí de les Escoles s/n
08916 Badalona, Barcelona, Spain

Office 2-17 Lab 2-15 (second floor)

Twitter: @MarcusBuschbeck

Directions

Summary

Epigenetic information is written in chromatin. But how exactly do epigenetic mechanisms operate on the molecular level? How do chromatin alterations contribute to cell fate transitions? How does the environment influence these processes? And how does the metabolic state of a cell impact on its chromatin structure and its epigenetic memory?

These are the questions we address in the lab. Studying stem cells and cancer we focus on molecular aspects of epigenetic regulation and on the question of whether we can translate this knowledge into diagnostic and therapeutic tools for the management of diseases such as acute myeloid leukemia and myelodysplastic syndrome.

Research

In our scientific approach we combine biochemical techniques, genetic manipulation of cell cultures and ultrasequencing of enriched chromatin fractions to address mechanistic and functional aspects of epigenetics. Key findings are validated in vivo. For the study of cancer we combine established cell lines, primary cultures and other patient samples.

Ongoing projects in the lab are related to the several of the following themes:

  •    The link between metabolism and epigenetic regulation.
  •    The regulation and molecular function of histone variants.
  •    Nuclear organization and 3D chromatin architecture
  •    Chromatin regulators as drug targets in myeloid diseases.

 

These are two examples of ongoing projects:

Chromatin modifiers as drug targets in MDS and cancer

Intrinsic and acquired resistances are the main reason for failure of current cancer treatments. For best treatments initial responses are limited to less than 50% of patients and virtually all responders eventually relapse and progress. The main goal of this study is to identify urgently needed response-predicting biomarkers and new combinatorial drug targets to increase rate and durability of response.

We coordinate the RESPONSE network (PIE16/00011) that brings together clinical and experimental groups. Together we we focus on three major cancers and their current treatments: advanced colorectal and lung cancer treated with chemotherapy and high-risk myelodysplastic syndrome treated with azacitidine.

To achieve our goals we combine the power of genetic screening technology with the analysis of highly informative clinical sample collections. We focus on transcriptional and chromatin regulators as a promising yet underexplored group of drug effectors. We examine drug-sensitizing genes and pathways with the aim to determine new drug targets for combinational therapy. Our long-term goal is to maximally advance the preclinical studies enabling the design of well-informed clinical trials. Using transcriptomic and epigenomic techniques we will further dissect the molecular function of most relevant effector genes.

The regulation and function of the macroH2A histone variants

Histones form the protein core of the nucleosome, which is the modular building block of chromatin structure. Histone variants endow chromatin with unique properties and show a specific genomic distribution. The histone variants macroH2A are unique in having a tripartite structure consisting of a N-terminal histone-fold, an intrinsically unstructured linker domain and a C-terminal macro domain. Recently, we have made two major discoveries. First, macroH2A proteins have a major role in the nuclear organization (Douet et al., 2017, JCS; Kozlowski, Corujo et al., 2018, EMBO Rep). This has the potential to explain how these proteins can act as tumor suppressors, promoters of differentiation and barriers to somatic ecll reprogramming (discussed in Buschbeck and Hake, 2017, Nature Reviews).

Second, we have identified the macroH2A1.1 isoform to be part of amolecular mechanism allowing cells to couple the metabolic requirements between distant organelles such as nucleus and mitochondria. Specifically, we found that macroH2A1.1 binds nuclear PARP1 and dampens its NAD+ consumption thereby creating a buffer of NAD+ precursors facilitating NAD+ dependent reactions in other organelles, such as respiration in mitochondria (Posavec Marjanovic, Hurtado-Bagès et al., 2017, NSMB). As co-coordinators of the MSCA ITN 'ChroMe', we are further pursuing additional research lines at the intersection of the chromatin and metabolism fields.

People

Selected publications

Kozlowski M, Corujo D, Hothorn M, Guberovic I, Mandemaker IK, Blessing C, Sporn J, Gutierrez-Triana A, Smith R, Portmann T, Treier M, Scheffzek K, Huet S, Timinszky G, Buschbeck M, Ladurner AG

MacroH2A histone variants limit chromatin plasticity through two distinct mechanisms.

EMBO Rep. Oct 2018, 19 (10) . Epub 3 Set 2018
MacroH2A histone variants suppress tumor progression and act as epigenetic barriers to induced pluripotency. How they impart their influence on chromatin plasticity is not well understood. Here, we analyze how the different domains of macroH2A proteins contribute to chromatin structure and dynamics. By solving the crystal structure of the macrodomain of human macroH2A2 at 1.7 Å, we find that its putative binding pocket exhibits marked structural differences compared with the macroH2A1.1 isoform, rendering macroH2A2 unable to bind ADP-ribose. Quantitative binding assays show that this specificity is conserved among vertebrate macroH2A isoforms. We further find that macroH2A histones reduce the transient, PARP1-dependent chromatin relaxation that occurs in living cells upon DNA damage through two distinct mechanisms. First, macroH2A1.1 mediates an isoform-specific effect through its ability to suppress PARP1 activity. Second, the unstructured linker region exerts an additional repressive effect that is common to all macroH2A proteins. In the absence of DNA damage, the macroH2A linker is also sufficient for rescuing heterochromatin architecture in cells deficient for macroH2A.
Més informació
Palau A, Garz AK, Diesch J, Zwick A, Malinverni R, Valero V, Lappin K, Casquero R, Lennartsson A, Zuber J, Navarro T, Mills KI, Götze KS, Buschbeck M

Polycomb protein RING1A limits hematopoietic differentiation in myelodysplastic syndromes.

Oncotarget 29 Des 2017, 8 (70) 115002-115017. Epub 1 Des 2017
Genetic lesions affecting epigenetic regulators are frequent in myelodysplastic syndromes (MDS). Polycomb proteins are key epigenetic regulators of differentiation and stemness that act as two multimeric complexes termed polycomb repressive complexes 1 and 2, PRC1 and PRC2, respectively. While components and regulators of PRC2 such as ASXL1 and EZH2 are frequently mutated in MDS and AML, little is known about the role of PRC1. To analyze the role of PRC1, we have taken a functional approach testing PRC1 components in loss- and gain-of-function experiments that we found overexpressed in advanced MDS patients or dynamically expressed during normal hematopoiesis. This approach allowed us to identify the enzymatically active component RING1A as the key PRC1 component in hematopoietic stem cells and MDS. Specifically, we found that RING1A is expressed in CD34
Més informació
Marjanović MP, Hurtado-Bagès S, Lassi M, Valero V, Malinverni R, Delage H, Navarro M, Corujo D, Guberovic I, Douet J, Gama-Perez P, Garcia-Roves PM, Ahel I, Ladurner AG, Yanes O, Bouvet P, Suelves M, Teperino R, Pospisilik JA, Buschbeck M

MacroH2A1.1 regulates mitochondrial respiration by limiting nuclear NAD(+) consumption.

Nat. Struct. Mol. Biol. 9 Oct 2017, . Epub 9 Oct 2017
Histone variants are structural components of eukaryotic chromatin that can replace replication-coupled histones in the nucleosome. The histone variant macroH2A1.1 contains a macrodomain capable of binding NAD(+)-derived metabolites. Here we report that macroH2A1.1 is rapidly induced during myogenic differentiation through a switch in alternative splicing, and that myotubes that lack macroH2A1.1 have a defect in mitochondrial respiratory capacity. We found that the metabolite-binding macrodomain was essential for sustained optimal mitochondrial function but dispensable for gene regulation. Through direct binding, macroH2A1.1 inhibits basal poly-ADP ribose polymerase 1 (PARP-1) activity and thus reduces nuclear NAD(+) consumption. The resultant accumulation of the NAD(+) precursor NMN allows for maintenance of mitochondrial NAD(+) pools that are critical for respiration. Our data indicate that macroH2A1.1-containing chromatin regulates mitochondrial respiration by limiting nuclear NAD(+) consumption and establishing a buffer of NAD(+) precursors in differentiated cells.
Més informació
Douet J, Corujo D, Malinverni R, Renauld J, Sansoni V, Marjanović MP, Cantari'o N, Valero V, Mongelard F, Bouvet P, Imhof A, Thiry M, Buschbeck M

MacroH2A histone variants maintain nuclear organization and heterochromatin architecture.

J. Cell. Sci. 10 Mar 2017, . Epub 10 Mar 2017
Genetic loss-of-function studies in development, cancer and somatic cell reprogramming have suggested that the group of macroH2A histone variants might function through stabilizing the differentiated state by a yet unknown mechanism. Here, we present results demonstrating that macroH2A variants have a major function in maintaining nuclear organization and heterochromatin architecture. Specifically, we find that a substantial amount of macroH2A is associated with heterochromatic repeat sequences. We further identify macroH2A on sites of interstitial heterochromatin decorated by H3K9me3. Loss of macroH2A leads to major defects in nuclear organization including reduced nuclear circularity, disruption of nucleoli and a global loss of dense heterochromatin. Domains formed by repeat sequences when depleted of macroH2A are disorganized, expanded and fragmented and mildly re-expressed. On the molecular level we find that macroH2A is required for the interaction of repeat sequences with the nucleostructural protein Lamin B1. Taken together our results argue that a major function of macroH2A histone variants is to link nucleosome composition to higher order chromatin architecture.
Més informació
Buschbeck M, Hake SB

Variants of core histones and their roles in cell fate decisions, development and cancer.

Nat. Rev. Mol. Cell Biol. 1 Feb 2017, . Epub 1 Feb 2017
Histone variants endow chromatin with unique properties and show a specific genomic distribution that is regulated by specific deposition and removal machineries. These variants - in particular, H2A.Z, macroH2A and H3.3 - have important roles in early embryonic development, and they regulate the lineage commitment of stem cells, as well as the converse process of somatic cell reprogramming to pluripotency. Recent progress has also shed light on how mutations, transcriptional deregulation and changes in the deposition machineries of histone variants affect the process of tumorigenesis. These alterations promote or even drive cancer development through mechanisms that involve changes in epigenetic plasticity, genomic stability and senescence, and by activating and sustaining cancer-promoting gene expression programmes.
Més informació
Show all publications

Current projects

LAS VARIANTES DE HISTONAS MACROH2A VINCULAN LA ARQUITECTURA DEL GENOMA AL METABOLISMO

Responsable:Marcus Buschbeck
Codi:BFU2015-66559-P
Financiadors:
Data d'inici:01/01/2016
Data de finalització:31/12/2018

International Nucleome Consortium

Responsable:Sarah Hurtado-Bagès
Codi:CA18127
Financiadors:
Data d'inici:26/10/2017
Data de finalització:25/10/2021

Chromatin-metabolism interactions as targets for healthy living (ChroMe)

Responsable:Marcus Buschbeck
Codi:ChroMe
Financiadors:
Data d'inici:01/03/2016
Data de finalització:29/02/2020

RESPONSE

Responsable:Marcus Buschbeck
Codi:PIE16/00011
Financiadors:
Data d'inici:01/01/2017
Data de finalització:31/12/2019

Previous projects

Drug repositioning as a fast and cost effective approach to personalized therapies. A pilot study on myelodysplastic syndrome and acute myeloid leukaemia

Responsable:Marcus Buschbeck
Codi:AECC_IMPPC_MB_2015
Financiadors:
Data d'inici:28/02/2014
Data de finalització:31/03/2016

Plan Nacional - Epigenetic Regulators of Stem Cell Function

Responsable:Marcus Buschbeck
Codi:SAF2012-39749
Financiadors:
Data d'inici:01/01/2013
Data de finalització:31/12/2015

Dissecting the Role of Polycomb Complexes in the Pathogenesis of Myelodysplastic Syndromes (MDS) and the Evolution to Acute Myeloid Leukemia (DJCLS R 14/16)

Responsable:Marcus Buschbeck
Codi:DJCLS R 14/16
Financiadors:
Data d'inici:01/08/2015
Data de finalització:31/07/2017

How does the histone variant macroH2A regulate muscle metabolism in health and disease?

Responsable:Marcus Buschbeck
Codi:18738
Financiadors:
Data d'inici:16/02/2015
Data de finalització:26/10/2017