title: Small-molecule inhibitors of the Wnt pathway potently promote cardiomyocytes from human embryonic stem cell-derived mesoderm.
abstract: BACKGROUND
  Human embryonic stem cells can form cardiomyocytes when cultured under differentiation conditions. Although the initiating step of mesoderm formation is well characterized, the subsequent steps that promote for cardiac lineages are poorly understood and limit the yield of cardiomyocytes.
  
  
  OBJECTIVE
  Our aim was to develop a human embryonic stem cell-based high-content screening assay to discover small molecules that drive cardiogenic differentiation after mesoderm is established to improve our understanding of the biology involved. Screening of libraries of small-molecule pathway modulators was predicted to provide insight into the cellular proteins and signaling pathways that control stem cell cardiogenesis.
  
  
  RESULTS
  Approximately 550 known pathway modulators were screened in a high-content screening assay, with hits being called out by the appearance of a red fluorescent protein driven by the promoter of the cardiac-specific MYH6 gene. One potent small molecule was identified that inhibits transduction of the canonical Wnt response within the cell, which demonstrated that Wnt inhibition alone was sufficient to generate cardiomyocytes from human embryonic stem cell-derived mesoderm cells. Transcriptional profiling of inhibitor-treated compared with vehicle-treated samples further indicated that inhibition of Wnt does not induce other mesoderm lineages. Notably, several other Wnt inhibitors were very efficient in inducing cardiogenesis, including a molecule that prevents Wnts from being secreted by the cell, which confirmed that Wnt inhibition was the relevant biological activity.
  
  
  CONCLUSIONS
  Pharmacological inhibition of Wnt signaling is sufficient to drive human mesoderm cells to form cardiomyocytes; this could yield novel tools for the benefit of pharmaceutical and clinical applications.
authors: Sanford-Burnham Medical Research Institute, La Jolla, CA 92037, USA.
authors: Erik
authors: E
authors: Willems
authors: Sean
authors: S
authors: Spiering
authors: Herman
authors: H
authors: Davidovics
authors: Marion
authors: M
authors: Lanier
authors: Zebin
authors: Z
authors: Xia
authors: Marcia
authors: M
authors: Dawson
authors: John
authors: J
authors: Cashman
authors: Mark
authors: M
authors: Mercola
mesh_terms: D024722:Cardiac Myosins / Q000235:genetics; D002454:Cell Differentiation / Q000187:drug effects*; D002460:Cell Line; D004305:Dose-Response Relationship, Drug; D055808:Drug Discovery; D053595:Embryonic Stem Cells / Q000187:drug effects* / Q000378:metabolism; D020869:Gene Expression Profiling; D018507:Gene Expression Regulation, Developmental / Q000187:drug effects; D017930:Genes, Reporter; D057166:High-Throughput Screening Assays; D006801:Humans; D008164:Luminescent Proteins / Q000096:biosynthesis / Q000235:genetics; D008648:Mesoderm / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D008856:Microscopy, Fluorescence; D032383:Myocytes, Cardiac / Q000187:drug effects* / Q000378:metabolism; D018995:Myosin Heavy Chains / Q000235:genetics; D011401:Promoter Regions, Genetic / Q000187:drug effects; D015398:Signal Transduction / Q000187:drug effects*; D054852:Small Molecule Libraries; D013997:Time Factors; D014162:Transfection; D051153:Wnt Proteins / Q000037:antagonists & inhibitors* / Q000378:metabolism; D000097573:Red Fluorescent Protein
chemical_list: D024722:Cardiac Myosins; D008164:Luminescent Proteins; D018995:Myosin Heavy Chains; D054852:Small Molecule Libraries; D051153:Wnt Proteins; D000097573:Red Fluorescent Protein; C094239:MYH6 protein, human