Abstract
Cardiosphere-derived cells (CDCs) effect therapeutic regeneration after myocardial infarction (MI) both in animal models and in humans. Here, we test the hypothesis that cell-cell contact plays a role in mediating the observed therapeutic benefits of CDCs, above and beyond conventional paracrine effects. Human CDCs or vehicle were injected into immunodeficient (SCID) mouse hearts during acute MI. CDC transplantation augmented the proportion of cycling (Ki67+) cardiomyocytes and improved ventricular function. CDC-conditioned media only modestly augmented the percentage of Ki67+ cardiomyocytes (>control but + or BrdU+ nuclei) increased relative to solitary NRVM culture. To further dissect the relative contributions of soluble factors versus contact-dependent mechanisms, we compared CDCs grown with NRVMs in a transwell contact-free system versus admixed coculture. The percentage of cycling NRVMs was higher in admixed coculture than in the contact-free system. Pretreatment with inhibitors of MEK and PI3K, or with β1 integrin neutralizing antibody, blocked the ability of CDCs to promote myocyte cycling. While conditioned media are not inert, direct apposition of CDCs to cardiomyocytes produces greater enhancement of cardiomyocyte proliferation in vitro and in vivo, and improves function post-MI. Intact cardiomyocyte β1 integrin signaling is necessary for the contact-dependent cardioproliferative effects of CDCs. Stem Cells 2014;32:2397-2406
Original language | English (US) |
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Pages (from-to) | 2397-2406 |
Number of pages | 10 |
Journal | Stem Cells |
Volume | 32 |
Issue number | 9 |
DOIs | |
State | Published - 2014 |
Externally published | Yes |
Keywords
- Cardiomyocyte
- Cardiosphere-derived cells
- Cell-cell communication
- Paracrine factors
- Proliferation
- β1 integrin
ASJC Scopus subject areas
- Cell Biology
- Developmental Biology
- Molecular Medicine