The heart is the first organ to form and has a complex structure consisting of many specialized cell types populating the heart muscle, blood vessels, and connective tissue. During early cardiac development, cells must multiply rapidly but also specify, i.e. limit their developmental potential and determine into which cell type they will later differentiate. Our group investigates how different cardiovascular progenitor populations arise, specify, and differentiate, notably by dissecting lineage trajectories via single-cell transcriptomics and chromatin accessibility profiling. We are particularly interested in how these processes are disrupted in congenital heart defects and how we can use knowledge from development to develop new regenerative approaches in adults. 

One of our areas of interest is the role of transcription factors such as Isl1, which during heart development is expressed in so-called second heart field (SHF) cardiovascular progenitors that later mainly contribute to the right ventricle, the outflow tract and portions of the atria.

left: Whole-mount immunohistological staining of an Isl1Cre/+;R26mTmG/+ embryo at embryonic day 9.5 showing Isl1-Cre mediated mG (green) marking of SHF progenitors and their derivatives.

rechts: Immunohistological staining of a heart section from an Isl1Cre/+;R26mTmG/+ mouse at 4 weeks, showing Isl1-Cre mediated mG (green) marking of the right ventricle, parts of the left ventricle and both atria. Perilipin1 (magenta) marks adipocytes.

Human induced pluripotent stem cells (hiPSCs) are stem cells that are derived from the somatic cells (e.g. blood or skin cells) of healthy individuals or patients. They have the capacity to self-renew indefinitely and to give rise to any cell type of the body in vitro, making them an exceptionally powerful tool for studying human disease in patient-specific backgrounds. A major focus of our research is using hiPSC-based disease modelling to gain insights into the molecular and cellular mechanisms involved in cardiovascular disorders such as arrhythmogenic right ventricular cardiomyopathy (ARVC), hypoplastic left heart syndrome (HLHS), cardiomyopathy associated with Noonan syndrome, left ventricular non-compaction (LVNC), and others. Once a therapeutic target has been identified, we also use hiPSC-derived cells as a platform for testing novel therapies, as we have previously done for Duchenne muscular dystrophy (DMD).

left: Confocal immunofluorescence image of hiPSC-derived cardiomyocytes stained for the sarcomere proteins cardiac troponin T (red) and a-actinin (green). Scale bar: 50 µm.

right: Live immunofluorescence imaging of a 3D cardiac spheroid derived from a double reporter stem cell line expressing eGFP and mCherry in the endogenous loci of the cardiac transcription factors NKX2.5 and TBX5, respectively. Scale bar: 200 µm.

As cells cultured in 2D fail to recapitulate certain features of their in vivo counterparts, part of our work is dedicated to developing 3D cardiac models that better mimic the physiology of heart tissue. We routinely produce engineered heart tissue based on hiPSC-derived cardiac cells seeded on decellularized ventricular matrix from pigs or non-human primates, which we cultivate in a biomimetic chamber system promoting tissue maturation by continuous mechanical and electrical stimulation. We have also established an ex vivo embryo culture system that allows us to study the function of human cardiac cells in human-mouse or human-pig chimeras. Finally, we recently generated human pluripotent stem cell-derived cardiac organoids showing morphological, functional, and molecular self-organization of ventricular myocardium and epicardium. 

left: Confocal immunofluorescence image of a cardiac organoid section showing the outer epicardial layer (tight junction protein 1 staining in yellow), the subjacent epicardium-derived cells (EPDCs) having undergone epithelial-to-mesenchymal transition (vimentin staining in magenta) and the myocardial layer (cardiac troponin T staining in green). Scale bar: 50 µm.

right: Biomimetic chamber containing engineered heart tissue undergoing radiofrequency ablation to mimic an acute myocardial injury.

• Generation, culture and differentiation of human pluripotent stem cells in 2D and 3D
• CRISPR/Cas9 gene editing for the generation of engineered reporter lines and knock-in/knock-out lines
• Functional characterization of cardiomyocytes via calcium imaging, optical action potential recordings, contractility measurements
• Bulk and single-cell RNA-sequencing and ATAC-sequencing
• Immunofluorescence analysis, confocal microscopy
• Flow cytometry and FACS sorting
• Cell injection in embryos and ex vivo embryo culture
• Molecular biology techniques including cloning, digital PCR
• Capillary Western Blot, chromatin immunoprecipitation

• Prof. Dr. Alessandra Moretti
  Chair of Regenerative Medicine of Cardiovascular Diseases, group leader
• Dr. Tatjana Dorn
  Senior scientist (developmental biology, lineage decision)
• Dr. Monika Nowak-Imialek
  Veterinarian scientist (porcine expanded pluripotent stem cells & human-pig chimeras)
• Dr. Gianluca Santamaria
  Postdoc (bioinformatic data analysis)
• Dr. Alexander Göedel
  Physician scientist (bioinformatic data analysis)
• Dr. Christine Schneider
  Physician scientist (3D tissue engineering & functional imaging)
• Sophie Zengerle
  PhD student (organoids and modeling of congenital heart disease) 
• Sinem Sürmeli
  PhD student (CRISPR-based genome editing) 
• Luis Felipe Monge Mora
  PhD student (cardiac organiods and imaging) 
• Marco Crovella
  Technician (animals and histology)
• Christina Scherb
  Technician (molecular biology)
• Birgit Campbell
  Technician (cell culture and iPSC generation)
• Aylin Mayer
  Technician (heart tissue slices andd gene editing)

Scientific Projects:
We regularly offer projects for diploma, PhD and M.D. students.

Third-Party Funding:

• European Research Council - EPICURE
• German Research Foundation

• German Centre for Cardiovascular Research, Munich Heart

  
  Alliance

• Else Kröner-Fresenius Foundation

Original work

Rawat H, Kornherr J, Zawada D, Bakhshiyeva S, Kupatt C, Laugwitz KL, Bähr A, Dorn T, Moretti A, Nowak-Imialek M. (2023) Recapitulating porcine cardiac development in vitro: from expanded potential stem cell to embryo culture models. Front Cell Dev Biol. 11:1111684. doi: 10.3389/fcell.2023.1111684. PMID: 37261075

Poch CM, Dendorfer A, Laugwitz KL, Moretti A. (2023) Ex vivo Culture and Contractile Force Measurements of Non-human Primate Heart Slices. Bio Protoc. 13(13):e4750. doi: 10.21769/BioProtoc.4750. PMID: 37456341

Meier AB, Zawada D, De Angelis MT, Martens LD, Santamaria G, Zengerle S, Nowak-Imialek M, Kornherr J, Zhang F, Tian Q, Wolf CM, Kupatt C, Sahara M, Lipp P, Theis FJ, Gagneur J, Goedel A, Laugwitz KL, Dorn T, Moretti A. (2023) Epicardioid single-cell genomics uncovers principles of human epicardium biology in heart development and disease. Nat Biotechnol. 41(12):1787-1800. doi: 10.1038/s41587-023-01718-7. PMID: 37012447

Zawada D, Kornherr J, Meier AB, Santamaria G, Dorn T, Nowak-Imialek M, Ortmann D, Zhang F, Lachmann M, Dreßen M, Ortiz M, Mascetti VL, Harmer SC, Nobles M, Tinker A, De Angelis MT, Pedersen RA, Grote P, Laugwitz KL, Moretti A, Goedel A. (2023) Retinoic acid signaling modulation guides in vitro specification of human heart field-specific progenitor pools. Nat Commun. 14(1):1722. doi: 10.1038/s41467-023-36764-x. PMID: 37012244

Poch CM, Foo KS, De Angelis MT, Jennbacken K, Santamaria G, Bähr A, Wang QD, Reiter F, Hornaschewitz N, Zawada D, Bozoglu T, My I, Meier A, Dorn T, Hege S, Lehtinen ML, Tsoi YL, Hovdal D, Hyllner J, Schwarz S, Sudhop S, Jurisch V, Sini M, Fellows MD, Cummings M, Clarke J, Baptista R, Eroglu E, Wolf E, Klymiuk N, Lu K, Tomasi R, Dendorfer A, Gaspari M, Parrotta E, Cuda G, Krane M, Sinnecker D, Hoppmann P, Kupatt C, Fritsche-Danielson R, Moretti A, Chien KR, Laugwitz KL. (2022) Migratory and anti-fibrotic programmes define the regenerative potential of human cardiac progenitors. Nat Cell Biol. 24(5):659-671. doi: 10.1038/s41556-022-00899-8. PMID: 35550611

Esfandyari D, Idrissou BMG, Hennis K, Avramopoulos P, Dueck A, El-Battrawy I, Grüter L, Meier MA, Näger AC, Ramanujam D, Dorn T, Meitinger T, Hagl C, Milting H, Borggrefe M, Fenske S, Biel M, Dendorfer A, Sassi Y, Moretti A, Engelhardt S. (2022) MicroRNA-365 regulates human cardiac action potential duration. Nat Commun. 13(1):220. doi: 10.1038/s41467-021-27856-7. PMID: 35017523

Krane M, Dreßen M, Santamaria G, My I, Schneider CM, Dorn T, Laue S, Mastantuono E, Berutti R, Rawat H, Gilsbach R, Schneider P, Lahm H, Schwarz S, Doppler SA, Paige S, Puluca N, Doll S, Neb I, Brade T, Zhang Z, Abou-Ajram C, Northoff B, Holdt LM, Sudhop S, Sahara M, Goedel A, Dendorfer A, Tjong FVY, Rijlaarsdam ME, Cleuziou J, Lang N, Kupatt C, Bezzina C, Lange R, Bowles NE, Mann M, Gelb BD, Crotti L, Hein L, Meitinger T, Wu S, Sinnecker D, Gruber PJ, Laugwitz KL, Moretti A. (2021) Sequential Defects in Cardiac Lineage Commitment and Maturation Cause Hypoplastic Left Heart Syndrome. Circulation. 144(17):1409-1428. doi: 10.1161/CIRCULATIONAHA.121.056198. PMID: 34694888

Moretti A, Fonteyne L, Giesert F, Hoppmann P, Meier AB, Bozoglu T, Baehr A, Schneider CM, Sinnecker D, Klett K, Fröhlich T, Rahman FA, Haufe T, Sun S, Jurisch V, Kessler B, Hinkel R, Dirschinger R, Martens E, Jilek C, Graf A, Krebs S, Santamaria G, Kurome M, Zakhartchenko V, Campbell B, Voelse K, Wolf A, Ziegler T, Reichert S, Lee S, Flenkenthaler F, Dorn T, Jeremias I, Blum H, Dendorfer A, Schnieke A, Krause S, Walter MC, Klymiuk N, Laugwitz KL, Wolf E, Wurst W, Kupatt C (2020). Somatic gene editing ameliorates skeletal and cardiac muscle failure in pig and human models of Duchenne muscular dystrophy. Nat Med 26(2):207-214

Guo Y, Dorn T, Kühl SJ, Linnemann A, Rothe M, Pfister AS, Vainio S, Laugwitz KL, Moretti A*, Kühl M* (2019). The Wnt inhibitor Dkk1 is required for maintaining the normal cardiac differentiation program in Xenopus laevis. Dev Biol. 449:1-13.

Dorn T, Kornherr J, Parrotta EI, Zawada D, Ayetey H, Santamaria G, Iop L, Mastantuono E, Sinnecker D, Goedel A, Dirschinger RJ, My I, Laue S, Bozoglu T, Baarlink C, Ziegler T, Graf E, Hinkel R, Cuda G, Kääb S, Grace AA, Grosse R, Kupatt C, Meitinger T, Smith AG, Laugwitz KL, Moretti A. (2018) Interplay of cell-cell contacts and RhoA/MRTF-A signaling regulates cardiomyocyte identity. EMBO J 37:pii: e98133.

Chen Z, Xian W, Bellin M, Dorn T, Tian Q, Goedel A, Dreizehnter L, Schneider CM, Ward-van Oostwaard D, Ng JK, Hinkel R, Pane LS, Mummery CL, Lipp P, Moretti A, Laugwitz KL, Sinnecker D. (2017) Subtype-specific promoter-driven action potential imaging for precise disease modelling and drug testing in hiPSC-derived cardiomyocytes. Eur Heart J 38:292-301.

Rocchetti M, Sala L, Dreizehnter L, Crotti L, Sinnecker D, Mura M, Pane LS, Altomare C, Torre E, Mostacciuolo G, Severi S, Porta A, De Ferrari GM, George AL Jr, Schwartz PJ, Gnecchi M, Moretti A, Zaza A. (2017) Elucidating arrhythmogenic mechanisms of long-QT syndrome CALM1-F142L mutation in patient-specific induced pluripotent stem cell-derived cardiomyocytes. Cardiovasc Res 113:531-541.

Gramlich M, Pane LS, Zhou Q, Chen Z, Murgia M, Schötterl S, Goedel A, Metzger K, Brade T, Parrotta E, Schaller M, Gerull B, Thierfelder L, Aartsma-Rus A, Labeit S, Atherton JJ, McGaughran J, Harvey RP, Sinnecker D, Mann M, Laugwitz KL, Gawaz MP, Moretti A. (2015) Antisense-mediated exon skipping: a therapeutic strategy for titin-based dilated cardiomyopathy. EMBO Mol Med 7:562-76.

Dorn T, Goedel A, Lam JT, Haas J, Tian Q, Herrmann F, Bundschu K, Dobreva G, Schiemann M, Dirschinger R, Guo Y, Kühl SJ, Sinnecker D, Lipp P, Laugwitz KL, Kühl M, Moretti A. (2015). Direct nkx2-5 transcriptional repression of isl1 controls cardiomyocyte subtype identity. Stem Cells 33(4):1113-29.

Jung CB, Moretti A, Schnitzler MM, Iop L, Storch U, Bellin M, Dorn T, Ruppenthal S, Pfeiffer S, Goedel A, Dirschinger RJ, Seyfarth M, Lam JT, Sinnecker D, Gudermann T, Lipp P & Laugwitz K-L (2012). Dantrolene rescues arrhythmogenic RYR2 defect in a patient-specific stem cell model of catecholaminergic polymorphic ventricular tachycardia. EMBO Mol. Med. 3:180-191.

Moretti A, Bellin M, Welling A, Jung CB, Lam JT, Bott-Flügel L, Dorn T, Gödel A, Höhnke C, Hofmann F, Seyfarth M, Sinnecker D, Schömig A & Laugwitz K-L (2010). Patient-specific induced pluripotent stem cell models for long-QT syndrome. N. Engl. J. Med. 363: 1397-409.

Qyang Y, Martin-Puig S, Chiravuri M, Chen S, Xu H, Bu L, Jiang X, Lin L, Granger A, Moretti A, Caron L, Wu X, Clarke J, Taketo MM, Laugwitz K-L, Moon RT, Gruber P, Evans SM, Ding S & Chien KR (2007). The renewal and differentiation of Isl1+ cardiovascular progenitors are controlled by a Wnt/β-catenin pathway. Cell Stem Cell 1: 1-15.

Moretti A, Caron, L, Nakano, A, Lam, JT, Chen, Y, Qyang, Y, Sasaki, M, Yunfu, S, Evans, S, Laugwitz, K-L & Chien KR (2006). Multipotent embryonic isl1+ progenitor cells lead to cardiac, smooth muscle, and endothelial cell diversification. Cell 127: 1151-1166.

Laugwitz K-L, Moretti A, Lam J, Gruber P, Yinhong Chen, Woodard S, Lin L-Z, Cai C-L, Lu M, Reth M, Platoshyn O, Yuan J, Evans S & Chien KR (2005). Postnatal isl1+ cardioblasts enter fully differentiated cardiomyocyte lineages. Nature 433: 647-653.

Book chapters, Reviews and Editorials

Dirschinger R., Dorn T., Moretti A. (2019) Human Induced Pluripotent Stem Cells as Platform for Functional Examination of Cardiovascular Genetics in a Dish. In: Erdmann J., Moretti A. (eds) Genetic Causes of Cardiac Disease. Cardiac and Vascular Biology, vol 7. Springer, Cham

Sinnecker D, Moretti A. (2018) Induced Pluripotent Stem Cell-Derived Cardiomyocytes: Towards Personalized Therapeutic Strategies? In: Dierk Thomas, Carol Ann Remme (Eds.) Channelopathies in Heart Disease. Springer International Publishing, ISBN 978-3-319-77811-2.

Sinnecker D, Laugwitz KL, Moretti A. (2014) Induced pluripotent stem cell-derived cardiomyocytes for drug development and toxicity testing. Pharmacol Ther 143:246-52.

Moretti A, Laugwitz KL, Dorn T, Sinnecker D, Mummery C. (2013) Pluripotent stem cell models of human heart disease. Cold Spring Harb Perspect Med 3. pii: a014027.

Evans SM, Moretti A & Laugwitz KL (2010). MicroRNAs in a cardiac loop: progenitor or myocyte? Dev. Cell 19: 787-8.

Laugwitz K-L, Moretti A, Nakano A & Chien KR (2008). Islet-1 Cardiovascular Progenitors: A single source for heart lineages? Development 135: 193-205.

Chien KR, Moretti A & Laugwitz K-L (2004). ES cells to the Rescue. Science 306: 239-240.