Author + information
- Zhang Mingming,
- Dongdong Sun and
- Haichang Wang
Oncostatin M (OSM) is an inflammatory cytokine that belongs to the interleukin-6 (IL-6) class of cytokines. OSM exhibits many unique biological activities by activating the Oβ receptor. However, its role in myocardial I/R injury in mice remains unknown.
We investigated whether Notch3/Akt signaling is involved in the regulation of OSM-induced protection against cardiac ischemia/reperfusion injury. The effects of OSM were assessed in mice that underwent myocardial I/R injury by OSM treatment or by genetic deficiency of the OSM receptor Oβ. We investigated its effects on cardiomyocyte apoptosis and mitochondrial biogenesis and whether Notch3/Akt signaling was involved in the regulation of OSM-induced protection against cardiac I/R injury. The mice underwent 30 minutes of ischemia followed by 3h of reperfusion and were randomized to be treated with Notch3 siRNA (siNotch3) or lentivirus carrying Notch3 cDNA (Notch3) 72h before coronary artery ligation. Myocardial infarct size, cardiac function, cardiomyocyte apoptosis and mitochondria morphology in mice that underwent cardiac I/R injury were compared between groups. H9C2 cardiomyocytes were cultured in DMEM with 10% heat-inactivated fetal bovine serum (FBS), penicillin 100 IU/ml and streptomycin 10 ug/ml. For induction of simulated I/R injury, cells were cultured in D-Hanks solution in a modular incubator chamber (BioSpherix) with 1% O2, 5% CO2 and 94% N2 for 4h (to simulate ischemia for 4h), then exposed to an atmosphere of 21% O2, 5% CO2 and 74% N2 and cultured for 4 h (to simulate reperfusion for 4h). OSM (20nmol/ml, Sigma) was added to the media 3 days before SI/R in the H9C2 cardiomyocytes. Wortmannin (a specific PI3K inhibitor, 5×10-6 mol/L) was added to the media 24h before SI/R in the SI/R+Notch3+Wgroup.
OSM alleviated cardiac I/R injury by inhibiting cardiomyocyte apoptosis through promotion of Notch3 production, thus activating the PI3K/Akt pathway. OSM enhanced mitochondrial biogenesis and mitochondrial function in mice subjected to cardiac I/R injury. In contrast, OSM receptor Oβ knock out exacerbated cardiac I/R injury, decreased Notch3 production, enhanced cardiomyocyte apoptosis, and impaired mitochondrial biogenesis in cardiac I/R injured mice. The mechanism of OSM on cardiac I/R injury is partly mediated by the Notch3/Akt pathway. The in vitro study also demonstrated thatOSM inhibited H9C2 cell apoptosis. JC-1 fluorescence microscopy in H9C2 cells revealed that OSM increased mitochondrial membrane potential in the SI/R model.
These results suggest a novel role of Notch3/Akt signaling that contributes to OSM-induced protection against cardiac I/R injury. OSM is a potential novel therapeutic target for preventing myocardial I/R injury in mice.