Because the heart has negligible intrinsic capacity to regenerate new tissues to replace those lost to injury, there is currently no definitive heart failure treatment, other than organ transplantation. Recent studies have introduced the prospect of replacing damaged heart tissues with healthy cardiomyocytes derived from pluripotent stem cells. However, realizing the full therapeutic potential of stem cells faces numerous hurdles, including the potential for tumor formation, a low rate of cardiomyocyte formation, and an inadequate mechanistic understanding of cardiomyogenesis. Additionally, translational efforts are hampered by a lack of pharmaceutical agents to boost therapeutic effects of stem cells. Dorsomorphin, the first known small molecule inhibitor of the bone morphogenetic protein (BMP) signaling, is one of the most potent chemical inducers of cardiomyogenesis in mouse embryonic stem (ES) cells. Dorsomorphin treatment during the initial 24 to 48 hours of ES cell differentiation was sufficient for robust cardiomyocyte induction. Strikingly, the massive cardiac induction occurs apparently in the absence of mesoderm induction and at the expense of other mesoderm-derived lineages, including endothelial, smooth muscle and hematopoietic lineages. From these results, we hypothesize that a timely BMP signal inhibition commits the primitive multipotent progenitor cells toward the cardiomyocyte development. The present study takes advantage of this unique and powerful model of cardiac induction to elucidate the mechanism of cardiomyogenic commitment and differentiation.
In Aim 1, we examine in detail the effects of small molecule BMP inhibitors on mesoderm, cardiovascular progenitor and cardiomyocyte formation. By comparing the effects of dorsomorphin and an exclusively specific BMP inhibitor DMH1, we will test whether dorsomorphin's known off-target effects against the Flk1 kinase reduces overall mesoderm formation, and whether a pure BMP inhibitor could induce even greater cardiomyocyte formation.
In Aim 2, we will examine whether the Flk1+ mesoderm progenitor cells from DMH1-treated ES cells are preferentially committed to become cardiomyocytes. In addition, we will determine the molecular profile of the putative cardiac-committed progenitors induced by the DMH1 treatment. These studies will shed much needed light on the nature of cardiac progenitor cells.
In Aim 3, we will take the next logical step to test whether small molecules that robustly induce cardiomyocyte formation in vitro can have a beneficial impact on stem cell therapies to improve cardiac repair in a mouse model of myocardial injury. Utilizing the unique ability of small molecules to block BMP signaling in adult animals, we will explore the potential of in vivo stimulation of cardiomyocyte formation following ES cell transplantation. The present study, which utilizes the small molecule BMP inhibitors to probe the mechanism of cardiomyogenesis, will not only inform future stem cell-based strategies to treat heart disease, but provide valuable pharmaceutical agents to boost the therapeutic effects of stem cells.

Public Health Relevance

The prospect of replacing damaged heart tissue with healthy heart cells generated from stem cells offers real hope for millions of Americans who suffer from heart failure. Until recently, it was very difficult to reliably generate heart cells from stem cells, but we recently discovered a class of novel drugs that massively promote heart cell formation in stem cells. This project aims to study how these drugs promote heart cell formation and to examine whether they can boost the beneficial effects of stem cells in a mouse model of heart attacks.

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Research Project (R01)
Project #
3R01HL104040-04S1
Application #
8690200
Study Section
Myocardial Ischemia and Metabolism Study Section (MIM)
Program Officer
Adhikari, Bishow B
Project Start
2010-08-01
Project End
2015-04-30
Budget Start
2013-07-01
Budget End
2014-04-30
Support Year
4
Fiscal Year
2013
Total Cost
$56,503
Indirect Cost
$20,283
Name
Vanderbilt University Medical Center
Department
Internal Medicine/Medicine
Type
Schools of Medicine
DUNS #
004413456
City
Nashville
State
TN
Country
United States
Zip Code
37212
Yang, Tao; Chun, Young Wook; Stroud, Dina M et al. (2014) Screening for acute IKr block is insufficient to detect torsades de pointes liability: role of late sodium current. Circulation 130:224-34
Engers, Darren W; Frist, Audrey Y; Lindsley, Craig W et al. (2013) Synthesis and structure-activity relationships of a novel and selective bone morphogenetic protein receptor (BMP) inhibitor derived from the pyrazolo[1.5-a]pyrimidine scaffold of dorsomorphin: the discovery of ML347 as an ALK2 versus ALK3 selective MLPCN Bioorg Med Chem Lett 23:3248-52
Williams, Ch; Hong, Cc (2013) Making Models Work: Library Annotation through Phenoclustering. Drug Discov Today Dis Models 10:
Roden, Dan M; Hong, Charles C (2013) Stem cell-derived cardiomyocytes as a tool for studying proarrhythmia: a better canary in the coal mine? Circulation 127:1641-3
Wells, Quinn S; Becker, Jason R; Su, Yan R et al. (2013) Whole exome sequencing identifies a causal RBM20 mutation in a large pedigree with familial dilated cardiomyopathy. Circ Cardiovasc Genet 6:317-26
Hao, Jijun; Ao, Ada; Zhou, Li et al. (2013) Selective small molecule targeting *-catenin function discovered by in vivo chemical genetic screen. Cell Rep 4:898-904
Saeed, Omar; Otsuka, Fumiyuki; Polavarapu, Rohini et al. (2012) Pharmacological suppression of hepcidin increases macrophage cholesterol efflux and reduces foam cell formation and atherosclerosis. Arterioscler Thromb Vasc Biol 32:299-307
Wang, Hanmin; Hao, Jijun; Hong, Charles C (2011) Cardiac induction of embryonic stem cells by a small molecule inhibitor of Wnt/ýý-catenin signaling. ACS Chem Biol 6:192-7
Cross, Emily E; Thomason, Rebecca T; Martinez, Mitchell et al. (2011) Application of small organic molecules reveals cooperative TGFýý and BMP regulation of mesothelial cell behaviors. ACS Chem Biol 6:952-61
Ao, Ada; Williams, Charles H; Hao, Jijun et al. (2011) Modified mouse embryonic stem cell based assay for quantifying cardiogenic induction efficiency. J Vis Exp :

Showing the most recent 10 out of 12 publications