title: Thymosin beta 4 treatment after myocardial infarction does not reprogram epicardial cells into cardiomyocytes.
abstract: Myocardial infarction (MI) is one of the leading causes of morbidity and mortality world-wide. Whether endogenous repair and regenerative ability could be augmented by drug administration is an important issue for generation of novel therapeutic approach. Recently it was reported that in mice pretreated with thymosin beta 4 (TB4) and subsequently subjected to experimental MI, a subset of epicardial cells differentiated into cardiomyocytes. In clinical settings, epicardial priming with TB4 prior to MI is impractical. Here we tested if TB4 treatment after MI could reprogram epicardium into cardiomyocytes and augment the epicardium's injury response. Using epicardium genetic lineage trace line Wt1(CreERT2/+) and double reporter line Rosa26(mTmG/+), we found post-MI TB4 treatment significantly increased the thickness of epicardium and coronary capillary density. However, epicardium-derived cells did not adopt cardiomyocyte fate, nor did they migrate into myocardium to become coronary endothelial cells. Our result thus indicates that TB4 treatment after MI does not alter epicardial cell fate to include the cardiomyocyte lineage, providing both cautions and insights for the full exploration of the potential benefits of TB4 in the clinical settings. This article is part of a Special Issue entitled 'Possible Editorial'.
authors: Key Laboratory of Nutrition and Metabolism, Institute for Nutritional Sciences, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China. zhoubin@sibs.ac.cn
authors: Bin
authors: B
authors: Zhou
authors: Leah B
authors: LB
authors: Honor
authors: Qing
authors: Q
authors: Ma
authors: Jin-Hee
authors: JH
authors: Oh
authors: Ruei-Zeng
authors: RZ
authors: Lin
authors: Juan M
authors: JM
authors: Melero-Martin
authors: Alexander
authors: A
authors: von Gise
authors: Pingzhu
authors: P
authors: Zhou
authors: Tianyuan
authors: T
authors: Hu
authors: Lingjuan
authors: L
authors: He
authors: Kai Hong
authors: KH
authors: Wu
authors: Hui
authors: H
authors: Zhang
authors: Yuebo
authors: Y
authors: Zhang
authors: William T
authors: WT
authors: Pu
mesh_terms: D000818:Animals; D002454:Cell Differentiation / Q000187:drug effects; D051379:Mice; D009203:Myocardial Infarction / Q000188:drug therapy* / Q000378:metabolism; D032383:Myocytes, Cardiac / Q000166:cytology* / Q000187:drug effects*; D010496:Pericardium / Q000166:cytology* / Q000187:drug effects*; D013947:Thymosin / Q000494:pharmacology* / Q000627:therapeutic use*; D000099201:Thymosin beta(4)
chemical_list: D013947:Thymosin; D000099201:Thymosin beta(4)