We have previously demonstrated the use of genetically modified mesenchymal stem cells overexpressing Akt (Akt-MSC) for therapeutic myocardial protection and repair. More recently, we have shown that conditioned media from these cells can protect cardiomyocytes from hypoxia induced apoptosis in vitro and the myocardium from ischemic damage in vivo. Based on our observation that the protective effect of the conditioned media can occur earlier than 72 hours, we postulated that the actions of Akt-MSC on ischemic myocardium are paracrine in nature and mediated by specific secreted proteins with cytoprotective properties. Further studies have shown that these cells dramatically upregulated (40X) secreted frizzled related protein (Sfrp 2). Sfrp 2 has been shown to bind and antagonize the effects of members of the Wnt family of proteins some of which modulate cell survival or apoptosis. Indeed, our preliminary data showed that Wnts can be upregulated in hypoxic cardiomyocytes in vitro and in the myocardium following infarction in vivo. Based on these results, we hypothesize that (i) Sfrp 2 is involved in paracrine anti-apoptotic effect of Akt-MSCs in vivo (ii) administration of Sfrp 2 protein or gene will confer therapeutic protection against infarct damage in vivo; (iii) the observed protective effect of Sfrp 2 is due to its interruption of the Wnt signaling pathway by interacting and sequestering specific Wnt(s) that have pro-apoptotic properties. To test these hypotheses, we will knockdown the expression of Sfrp 2 in Akt-MSC by siRNA followed by injection of the cells or the conditioned media from the cells into the infarcted mouse hearts. We will then determine in vivo therapeutic efficacy by intramyocardial injections of purified, recombinant Sfrp 2 for protection against ischemic damage in vivo. In addition we will evaluate the effects of overexpression of Sfrp 2 using AAV-mediated expression using regulated and cell specific promoters. Subsequently, we will examine the mechanism of the protection by determining if Sfrp 2 regulates the canonical or the non-canonical Wnt signaling pathways by using in vitro and in vivo reporter assays. Finally we will find Wnts that have proapoptotic properties and determine the nature of interaction of Sfrp 2 with these proapoptotic Wnts. Our studies, if successful, will lead to discovery of novel pathways, mechanisms and may result in new modes of treatment for acute myocardial infarction. ? ? ?

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Research Project (R01)
Project #
5R01HL081744-03
Application #
7446063
Study Section
Myocardial Ischemia and Metabolism Study Section (MIM)
Program Officer
Buxton, Denis B
Project Start
2006-09-15
Project End
2010-06-30
Budget Start
2008-07-01
Budget End
2009-06-30
Support Year
3
Fiscal Year
2008
Total Cost
$502,653
Indirect Cost
Name
Duke University
Department
Internal Medicine/Medicine
Type
Schools of Medicine
DUNS #
044387793
City
Durham
State
NC
Country
United States
Zip Code
27705
Hodgkinson, Conrad P; Gomez, José A; Baksh, Syeda Samara et al. (2018) Insights from molecular signature of in vivo cardiac c-Kit(+) cells following cardiac injury and ?-catenin inhibition. J Mol Cell Cardiol 123:64-74
Dal-Pra, Sophie; Hodgkinson, Conrad P; Mirotsou, Maria et al. (2017) Demethylation of H3K27 Is Essential for the Induction of Direct Cardiac Reprogramming by miR Combo. Circ Res 120:1403-1413
Li, Yanzhen; Dal-Pra, Sophie; Mirotsou, Maria et al. (2016) Tissue-engineered 3-dimensional (3D) microenvironment enhances the direct reprogramming of fibroblasts into cardiomyocytes by microRNAs. Sci Rep 6:38815
Hodgkinson, Conrad P; Bareja, Akshay; Gomez, José A et al. (2016) Emerging Concepts in Paracrine Mechanisms in Regenerative Cardiovascular Medicine and Biology. Circ Res 118:95-107
Yuan, Hsiangkuo; Gomez, Jose A; Chien, Jennifer S et al. (2016) Tracking mesenchymal stromal cells using an ultra-bright TAT-functionalized plasmonic-active nanoplatform. J Biophotonics 9:406-13
Yang, Yanqiang; Gomez, Jose A; Herrera, Marcela et al. (2015) Salt restriction leads to activation of adult renal mesenchymal stromal cell-like cells via prostaglandin E2 and E-prostanoid receptor 4. Hypertension 65:1047-54
Jayawardena, Tilanthi M; Finch, Elizabeth A; Zhang, Lunan et al. (2015) MicroRNA induced cardiac reprogramming in vivo: evidence for mature cardiac myocytes and improved cardiac function. Circ Res 116:418-24
Hodgkinson, Conrad P; Kang, Martin H; Dal-Pra, Sophie et al. (2015) MicroRNAs and Cardiac Regeneration. Circ Res 116:1700-11
Schmeckpeper, Jeffrey; Verma, Amanda; Yin, Lucy et al. (2015) Inhibition of Wnt6 by Sfrp2 regulates adult cardiac progenitor cell differentiation by differential modulation of Wnt pathways. J Mol Cell Cardiol 85:215-25
Huang, Jing; Guo, Jian; Beigi, Farideh et al. (2014) HASF is a stem cell paracrine factor that activates PKC epsilon mediated cytoprotection. J Mol Cell Cardiol 66:157-64

Showing the most recent 10 out of 22 publications