Selective targeting of the BRG/PB1 bromodomains impairs embryonic and trophoblast stem cell maintenance

  • Sci Adv. 2015 Nov 13;1(10):e1500723. doi: 10.1126/sciadv.1500723.
Oleg Fedorov  1 ,  Josefina Castex  2 ,  Cynthia Tallant  1 ,  Dafydd R Owen  3 ,  Sarah Martin  1 ,  Matteo Aldeghi  4 ,  Octovia Monteiro  1 ,  Panagis Filippakopoulos  5 ,  Sarah Picaud  6 ,  John D Trzupek  3 ,  Brian S Gerstenberger  3 ,  Chas Bountra  1 ,  Dominica Willmann  2 ,  Christopher Wells  1 ,  Martin Philpott  1 ,  Catherine Rogers  1 ,  Philip C Biggin  7 ,  Paul E Brennan  1 ,  Mark E Bunnage  3 ,  Roland Schüle  8 ,  Thomas Günther  2 ,  Stefan Knapp  9 ,  Susanne Müller  1
Affiliations
  • 1. Target Discovery Institute, University of Oxford, NDM Research Building, Roosevelt Drive, Oxford OX3 7FZ, UK. ; Structural Genomics Consortium, University of Oxford, Old Road Campus Research Building, Roosevelt Drive, Oxford OX3 7DQ, UK.
  • 2. Urologische Klinik und Zentrale Klinische Forschung, Klinikum der Universität Freiburg, Breisacher Strasse 66, 79106 Freiburg, Germany.
  • 3. Pfizer Worldwide Medicinal Chemistry, 610 Main Street, Cambridge, MA 02139, USA.
  • 4. Target Discovery Institute, University of Oxford, NDM Research Building, Roosevelt Drive, Oxford OX3 7FZ, UK. ; Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK.
  • 5. Structural Genomics Consortium, University of Oxford, Old Road Campus Research Building, Roosevelt Drive, Oxford OX3 7DQ, UK. ; Ludwig Institute for Cancer Research, University of Oxford, Oxford OX3 7DQ, UK.
  • 6. Structural Genomics Consortium, University of Oxford, Old Road Campus Research Building, Roosevelt Drive, Oxford OX3 7DQ, UK.
  • 7. Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK.
  • 8. Urologische Klinik und Zentrale Klinische Forschung, Klinikum der Universität Freiburg, Breisacher Strasse 66, 79106 Freiburg, Germany. ; Deutsches Konsortium für Translationale Krebsforschung, Standort Freiburg, 79106 Freiburg, Germany. ; Institute for Pharmaceutical Chemistry and Buchmann Institute for Molecular Life Sciences, Johann Wolfgang Goethe-University, Max-von-Laue-Str. 9, D-60438 Frankfurt am Main, Germany.
  • 9. Target Discovery Institute, University of Oxford, NDM Research Building, Roosevelt Drive, Oxford OX3 7FZ, UK. ; Structural Genomics Consortium, University of Oxford, Old Road Campus Research Building, Roosevelt Drive, Oxford OX3 7DQ, UK. ; Institute for Pharmaceutical Chemistry and Buchmann Institute for Molecular Life Sciences, Johann Wolfgang Goethe-University, Max-von-Laue-Str. 9, D-60438 Frankfurt am Main, Germany.
PMID: 26702435 DOI: 10.1126/sciadv.1500723
Abstract

Mammalian SWI/SNF [also called Brg/Brahma-associated factors (BAFs)] are evolutionarily conserved chromatin-remodeling complexes regulating gene transcription programs during development and stem cell differentiation. BAF complexes contain an ATP (adenosine 5'-triphosphate)-driven remodeling enzyme (either BRG1 or BRM) and multiple protein interaction domains including bromodomains, an evolutionary conserved acetyl lysine-dependent protein interaction motif that recruits transcriptional regulators to acetylated chromatin. We report a potent and cell active protein interaction inhibitor, PFI-3, that selectively binds to essential BAF bromodomains. The high specificity of PFI-3 was achieved on the basis of a novel binding mode of a salicylic acid head group that led to the replacement of water molecules typically maintained in Other bromodomain inhibitor complexes. We show that exposure of embryonic stem cells to PFI-3 led to deprivation of stemness and deregulated lineage specification. Furthermore, differentiation of trophoblast stem cells in the presence of PFI-3 was markedly enhanced. The data present a key function of BAF bromodomains in stem cell maintenance and differentiation, introducing a novel versatile chemical probe for studies on acetylation-dependent cellular processes controlled by BAF remodeling complexes.

Keywords
BAF complex; BRG; BRM; PB1; chemical probe; chromatin remodelling,embryonic stem cells; epigenetics; trophoblast stem cells.
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