Sirtuin-3 (
Sirt3) has a critical role in the regulation of human aging and
reactive oxygen species (ROS) formation. A recent study has identified
Sirt3 as an essential regulator of stem cell aging. This study investigated whether
Sirt3 is necessary for bone marrow cell (BMC)-mediated cardiac repair in post-
myocardial infarction (MI). In vitro, BMC-derived endothelial progenitor cells (EPCs) from wild type (WT) and Sirt3KO mice were cultured.
EPC angiogenesis, ROS formation and apoptosis were assessed. In vivo, WT and
Sirt3 KO mice were subjected to MI and BMCs from WT and
Sirt3 KO mice were injected into ischemic area immediately. The expression of
VEGF and VEGFR2 was reduced in Sirt3KO-EPCs. Angiogenic capacities and colony formation were significantly impaired in Sirt3KO-EPCs compared to WT-EPCs. Loss of
Sirt3 further enhanced ROS formation and apoptosis in EPCs. Overexpression of
Sirt3 or treatment with
NADPH oxidase inhibitor
apocynin (Apo, 200 and 400 microM) rescued these abnormalities. In post-MI mice, BMC treatment increased number of
Sca1+/c-kit+ cells; enhanced
VEGF expression and angiogenesis whereas Sirt3KO-BMC treatment had little effects. BMC treatment also attenuated
NADPH oxidase subunits p47phox and gp91phox expression, and significantly reduced ROS formation, apoptosis,
fibrosis and
hypertrophy in post-MI mice. Sirt3KO-BMC treatment did not display these beneficial effects. In contrast, Sirt3KO mice treated with BMCs from WT mice attenuated myocardial apoptosis,
fibrosis and improved cardiac function. Our data demonstrate that
Sirt3 is essential for BMC
therapy; and loss of
Sirt3 limits BMC-mediated angiogenesis and cardiac repair in post-MI.