Hypoxic preconditioning of cardiomyocytes and cardioprotection: phophorylation of HIF- 1α induced by p42/p44 mitogen-activated protein kinases is involved  Xiuhua Liu, Xudong Wu, Lirong Cai, Chaoshu Tang, Jingyi Su  Pathophysiology  Volume 9, Issue 4, Pages 201-205 (September 2003) DOI: 10.1016/S0928-4680(03)00006-3

Fig. 1 Effects of HPC on H/R injury of neonatal cardiomyocytes. Cardiomyocytes were subjected to 3 h of hypoxia and 3 h of reoxygenation (H/R) either with or without preceding HPC 24 h early. HPC was carried out alone, with PD98059 (a selective inhibitor of MAPK kinase MEK-1/2: upstream activators of p42/44 MAPKs, 50 μmol/l) or with BDM (an activator of protein phosphatase, 20 mmol/l). PD98059 or BDM were present 10 min prior to HPC and during HPC. After 3 h of reoxygenation following 3 h of hypoxia, cardiomyocytes were stained with MTT to determine viability, and medium was collected for analysis of LDH release. H/R vs. control, HPC vs. H/R, PD and BDM vs. HPC: *P<0.05. Pathophysiology 2003 9, 201-205DOI: (10.1016/S0928-4680(03)00006-3)

Fig. 2 Time course of HPC on activities of p42/44 MAPKs in cardiomyocytes. Cardiomyocytes from different groups were harvested at 10, 30, and 60 min after HPC or the same time points in control group. The whole cell extracts were separated by SDS-PAGE, and the blots were incubated with the phospho-specific antibody against p42/p44-MAPKs. C, control cardiomyocytes cultured in normoxia; HPC, hypoxic preconditioned cardiomyocytes; PD, cardiomyocytes pretreated with D98059 (a selective inhibitor of MAPK kinase MEK-1/2: upstream activators of p42/44 MAPKs, 50 μmol/l) 10 min prior to HPC; BDM, cardiomyocytes pretreated with BDM (2,3-butanedione monoxide, an activator of protein phosphatase, 20 mmol/l) 10 min prior to HPC. Pathophysiology 2003 9, 201-205DOI: (10.1016/S0928-4680(03)00006-3)

Fig. 3 Effects of HPC on phosphorylation of HIF-1α in cardiomyocytes. Cardiomyocytes from different groups were harvested at 30 min after HPC or the same time points in control group. The whole cell extracts were separated by SDS-PAGE, and the blot was incubated with anti-HIF-1α. C, control cardiomyocytes cultured in normoxia; HPC, hypoxic preconditioned cardiomyocytes; PD, cardiomyocytes pretreated with PD98059 (a selective inhibitor of MAPK kinase MEK-1/2: upstream activators of p42/44 MAPKs, 50 μmol/l) 10 min prior to HPC; BDM, cardiomyocytes pretreated with BDM (2,3-butanedione monoxide, an activator of protein phosphatase, 20 mmol/l) 10 min prior to HPC. Pathophysiology 2003 9, 201-205DOI: (10.1016/S0928-4680(03)00006-3)