title: Oxidative stress-induced Notch1 signaling promotes cardiogenic gene expression in mesenchymal stem cells.
abstract: BACKGROUND
  Administration of bone marrow-derived mesenchymal stem cells (MSCs) after myocardial infarction (MI) results in modest functional improvements. However; the effect of microenvironment changes after MI, such as elevated levels of oxidative stress on cardiogenic gene expression of MSCs, remains unclear.
  
  
  METHODS
  MSCs were isolated from the bone marrow of adult rats and treated for 1 week with H2O2 (0.1 to 100 μM) or 48 hours with glucose oxidase (GOX; 0 to 5 mU/ml) to mimic long-term pulsed or short-term continuous levels of H2O2, respectively.
  
  
  RESULTS
  In 100 μM H2O2 or 5 mU/ml GOX-treated MSCs, mRNA expression of selected endothelial genes (Flt1, vWF, PECAM1), and early cardiac marker (nkx2-5, αMHC) increased significantly, whereas early smooth muscle markers (smooth muscle α-actin and sm22α) and fibroblast marker vimentin decreased, as measured with real-time PCR. Interestingly, mRNA expression and activity of the cell-surface receptor Notch1 were significantly increased, as were its downstream targets, Hes5 and Hey1. Co-treatment of MSCs with 100 μM H2O2 and a γ-secretase inhibitor that prevents Notch signaling abrogated the increase in cardiac and endothelial genes, while augmenting the decrease in smooth muscle markers. Further, on GOX treatment, a significant increase in Wnt11, a downstream target of Notch1, was observed. Similar results were obtained with adult rat cardiac-derived progenitor cells.
  
  
  CONCLUSIONS
  These data suggest that H2O2- or GOX-mediated oxidative stress upregulates Notch1 signaling, which promotes cardiogenic gene expression in adult stem/progenitor cells, possibly involving Wnt11. Modulating the balance between Notch activation and H2O2-mediated oxidative stress may lead to improved adult stem cell-based therapies for cardiac repair and regeneration.
authors.forename: Archana V
authors.initials: AV
authors.lastname: Boopathy
authors.forename: Karl D
authors.initials: KD
authors.lastname: Pendergrass
authors.forename: Pao Lin
authors.initials: PL
authors.lastname: Che
authors.forename: Young-Sup
authors.initials: YS
authors.lastname: Yoon
authors.forename: Michael E
authors.initials: ME
authors.lastname: Davis
mesh_terms: D000199:Actins / Q000378:metabolism; D000818:Animals; D001854:Bone Marrow Cells / Q000166:cytology; D002454:Cell Differentiation / Q000187:drug effects; D002478:Cells, Cultured; D004151:Dipeptides / Q000494:pharmacology; D015870:Gene Expression / Q000187:drug effects; D005949:Glucose Oxidase / Q000494:pharmacology; D006861:Hydrogen Peroxide / Q000633:toxicity; D008297:Male; D059630:Mesenchymal Stem Cells / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism; D009206:Myocardium / Q000166:cytology / Q000378:metabolism; D018384:Oxidative Stress / Q000187:drug effects; D034741:RNA, Small Interfering / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D051881:Receptor, Notch1 / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction / Q000187:drug effects; D013234:Stem Cells / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D051153:Wnt Proteins / Q000378:metabolism
chemical_list: D000199:Actins; D004151:Dipeptides; C419410:N-(N-(3,5-difluorophenacetyl)alanyl)phenylglycine tert-butyl ester; D034741:RNA, Small Interfering; D051881:Receptor, Notch1; D051153:Wnt Proteins; C502412:Wnt11 protein, rat; D006861:Hydrogen Peroxide; D005949:Glucose Oxidase