Abstract 21055: Direct Nicd1 Overexpression Enhances Cardiac Commitment of Cpcs and Improve Heart Repair After Acute Myocardial Infarction via Notch1/gata4 Signaling
Introduction: Ischemic heart disease is the leading cause of morbidity and mortality in the United States. The adult cardiomyocytes (CM) do not efficiently regenerate itself after injury. Cardiac progenitor cell (CPC) therapy is a promising new approach to restore heart function and prevent LV remodeling after acute myocardial infarction (MI), however, differentiation of CPCs to cardiiomyocytes is still low in vivo, and therapeutic effects of CPCs have been limited thus far. It was recently discovered that Notch1 regulates CPC commitment via comparison of CPCs in the presence or absence of a γ-secretase inhibitor. Here, we want to investigate whether direct overexpression of Notch 1 intracellular domain (NICD1), the active form of Notch1, could enhance cardiac commitment of CPCs, and preserve ventricular function after MI.
Methods and Results: The cardiosphere derived c-kit+ CPCs were isolated, characterized, and cultured on fibronectin coated dishes. Lentiviruses carrying the NICD1 gene or GFP gene were used to modify CPCs. C57/B6 mice (male, 2month old) underwent LAD ligation to induce MI. the NICD1 modified CPCs (NICD1-CPCs, 1x106 cells in 30ul) were intramyocardially injected into border zone of heart after LAD ligation, control animals received media or GFP-CSC only. LV function was assessed by high-resolution echocardiography at 2 weeks after cell transplantation. Two-dimensional and M-mode displacement images and strain images, as well as displacement and strain profiles, were compared among medium control, GFP-CPC control and NICD1-CPC mice. Our data showed that Notch1 positively regulated expression of the cardiac transcription factor, GATA4, which increase about 5.8 fold comparison to GFP-CPC control (p<0.01, n=3). Furthermore, Wnt11, the major Wnt ligand controlling heart differentiation, was 5.3 fold increased in the NCID CPCs comparison to GFP CPCs. NICD-CPC animals showed an improved preservation of ventricular function after MI (EF: 48.1%±4.2% in NICD1-CPC group vs 42.6%±4.4 in GFP-CPC group and 35.8%±9.4% in Medium control group, n=7).
Conclusions: Our data suggested that directly overexpressing the active form of Notch1 can facilitate commitment of CPC to cardiomyocytes, and enhance heart repair after ischemia injury.
- © 2010 by American Heart Association, Inc.