Introduction: Cardiac progenitor cells (CPCs) possess incredible repair properties in the neonatal heart but are prone to disease and age diminishing their efficacy. Interestingly, CPCs stemness is linked to a unique metabolic phenotype altered once cells undergo proliferation and commitment. Recent data indicates Lin28 as metabolic regulator of pluripotency, enhancing tissue repair after injury. Nevertheless, there are no studies characterizing the effect of Lin28 on CPC biology or cardiac repair.
Hypothesis: Determine the effect of Lin28 on CPC function and cardiac repair after injury.
Methods and Results: Lin28a expression coincides during embryonic heart development with c-kit and declines postnatal with complete abrogation in 3-week-old adult heart as measured by qRT-PCR and immunohistochemistry. Neonatal CPCs express Lin28a together with increased proliferation but expression is lost in adult CPCs along with decreased proliferation. Next, CPCs were engineered with Lin28a (CPCLinA) lentivirus along with mcherry while mcherry expressing CPCs were used as controls (CPCmc). CPCLinA demonstrated increased proliferation measured by CyQuant compared to CPCmc concurrent with decreased apoptosis measured by annexin-V based FACS analysis. Interestingly, CPCLinA demonstrated a significant enhancement of glycolysis, glycolytic capacity and glycolytic reserve together with increased expression of glycolytic enzymes compared to CPCmc as measured by seahorse assay and qRT-PCR respectively. Oxidative metabolism was also upregulated together with increased intracellular ATP in CPCLinA compared to controls. Additionally, CPCLinA demonstrated significantly reduced ROS generation as measured by CM-H2TMROS based FACS analysis compared to CPCmc. To determine in vivo efficacy, CPCLinA and CPCmc were transplanted in the heart after myocardial infarction. Increased proliferation (p-histone/Ki67) together with decreased TUNEL+ cells were observed in CPCLinA compared to control CPCmc hearts 2 days after transplantation.
Conclusions: Metabolic reprogramming of CPCs with Lin28a induces a shift towards glycolytic metabolism in CPCs enhancing proliferation and survival including ability to repair the heart after myocardial injury.