Direct Reprogramming of Fibroblasts into Cardiomyocytes

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1 Direct Reprogramming of Fibroblasts into Cardiomyocytes G. Hasenfuss No conflict Heart Center Heart Research Center Göttingen Georg-August-University Göttingen

2 Cardiac Regeneration Options in 5/2011 Stem cell-based pharmacotherapy (angiogenesis etc.) Bone marrow cells Cardiomyocyte-based regeneration Cell cycle Activation of CMs Endogenous transdifferentiation of non-cms Application of exogenous cells and tissues - Neonatal CM - Cardiospheres - ESCs - Adult SC (SSCs, magscs) - ips cells

3 Transcription factors necessary for reprogramming somatic cells into ips cells Yu J, Thomson JA (2007): Induced Pluripotent Stem Cell Lines Derived from Human Somatic Cells. Science 318: Takahashi K, Yamanaka S (2007): Induction of Pluripotent Stem Cells from Adult Human Fibroblasts by Defined Factor. Cell 131: Oct3/4 Sox2 Nanog Lin28 Epigenetic Reprogramming Oct3/4 Sox2 Klf4 c-myc (not necessary, Nat Biotechnol 26: , 2008)

4 Generation of ips cells Reprogramming of somatic cells Cell type Factors for reprogramming Blood Plasmid Virus Liver Skin Protein Small Molekule Analysis ips cells Cell Therapy Regeneration Drug Screening Pathophysiology

5 Guan et al 2010 ips Cells and Cardiac Cells from Patient Hair Keratinocytes from hair follicles ips-cell from keratinocytes ips-cell derived cardiomyoctyes Action potential Calcium transients

6 Problems associated with induced (reprogrammed) Pluripotent cells regarding regeneration Genertion Rejection Teratoma formation NK-Zelle Activating receptor Inhibitory receptor NKG2D No MHC Class I Stem cell Dressel et al., FASEB J 2010

7 More unresovled issues with ips cells Copy number variation and selection during reprogramming to pluripotency Hussein et al Nature, March 2011 Somatic coding mutations in human induced pluripotent stem cells Gore Nature, March 2011 Hotspots of aberrant epigenomic reprogramming in human induced pluripotent stem cells Lister et al Nature, March 2011

8 Reprogramming of Somatic Cells Xu et al., Nat Cell Biol 2011

9 Cardiomyocytes from Fibroblasts without a pluripotent state Conversion of mouse fibroblasts into cardiomyocytes using a direct reprogramming strategy Jem A. Efe1, Simon Hilcove1, Janghwan Kim1, Hongyan Zhou1, Kunfu Ouyang2, Gang Wang2, Ju Chen2 and Sheng Ding1,3 Nature Cell Biology 2011 Transient low level expression of Oct4 Sox2 Klf4 (c-myc)

10 Calcium cycling Efe et al., Nat Cell Biol 2011

11 Electrophysiology Efe et al., Nat Cell Biol 2011

12 Reprogramming of Somatic Cells 3 Transcription Factors: Gata4, Mef2C, Tbx5 Ieda et al Cell 2010 Xu et al., Nat Cell Biol 2011

13 Fibroblast Derived Cardiomyocytes Ieda et al., Cell 2010

14 Fibroblast Derived Cardiomyocytes Ieda et al., Cell 2010

15 Fibroblast Derived Cardiomyocytes Following intramyocardial injection of transfected fibroblasts with 3TF cardiomyocates develop in vivo Ieda et al., Cell 2010

16 Epigenetic modification of genes Histone octamere H3K27me3 H3K4 Histone modification -Acetylation -Phosphorylation -Methylation -Ubiqutination Promoter modification - Methylation Methylated cytosines H3K27 H3K4me3 Unmethylated cytosines Gene switched on : Active (open) chromatin

17 Histone Methylation Actin Ryanodine Receptor Troponin T Ieda et al., Cell 2010

18 DNA Methylation Natriuretic P. αmhc Ieda et al., Cell 2010

19 Reprogramming of Somatic Cells Xu et al., Nat Cell Biol 2011

20 Summary Direct reprogramming of fibroblasts into cardiomyocytes In vitro with subsequent cardiomyocyte transplantation - lower risk of tumors - no/little cell proliferation In vivo conversion of fibroblasts into cardiomyocytes - conversion of scar tissue into contractile tissue - procedure without retrovirus needed

21 Acknowledgements Kaomei Guan Frieder Wolf Alexander M. Becker Katrin Streckfuss-Boemeke Diana Kaiser Anke Cierpka Yvonne Hintz Bernhard Unsöld Lars Maier Stephan Wagner R. Dressesl Collaborators Institute of Human Genetics University of Göttingen Wolfgang Engel Indiana University School of Medicine, USA Loren Field Molecular Pharmacology, Univers. Göttingen W. Zimmermann M. Tiburcy This work was supported by a Heidenreich von Siebold-Program 2006 grant from University of Göttingen (K.G.), a Forschungs- und Berufungspool (Kapitel TG 74) grant of Ministry for Science and Culture of Lower Saxony (G.H.), and a BMBF grant G3-11(G.H.). The authors declare no conflict of interest