Granulocyte colony-stimulating factor (G-CSF) is used for heartfailure therapy and promotes myocardial regeneration byinducing mobilization of bone marrow stem cells to the injuredheart after myocardial infarction; however, this treatment hasone weakness in that its biological effect is transient. In ourprevious report, we generated 5 mutants harboring N-linkedglycosylation to improve its antiapoptotic activities. Amongthem, one mutant (Phe140Asn) had higher cell viability thanwild-type hG-CSF in rat cardiomyocytes, even after treatmentwith an apoptotic agent (H2O2). Cells treated with this mutantsignificantly upregulated the antiapoptotic proteins, andexperienced reductions in caspase 3 activity and PARPcleavage. Moreover, the total number of apoptotic cells wasdramatically lower in cultures treated with mutant hG-CSF.Taken together, these results suggest that the addition of anN-linked glycosylation was successful in improving theantiapoptotic activity of hG-CSF, and that this mutated productwill be a feasible therapy for patients who have experiencedheart failure.