title: Hyperglycemia and reactive oxygen species mediate apoptosis in aortic endothelial cells through Janus kinase 2.
abstract: The generation of reactive oxygen species (ROS) has been implicated in the perturbation of endothelial function and cell death. However, the specific signaling pathways which mediate and modifying this response have not been fully elucidated. Therefore, in this study we tested the hypothesis that activation of JAK2 is involved in the aortic endothelial cell (EC) response to ROS. When ECs were exposed to HG (25 mM) for 6 h or ROS (i.e., H(2)O(2) (100 microM)) for 1 h and returned to normal medium we found a decrease in cell density and morphologic signs of apoptosis. Furthermore, incubation of ECs with HG and H(2)O(2) also resulted in the tyrosine phosphorylation of JAK2. In addition, pretreatment of ECs with AG-490, an inhibitor of JAK2, prevented nuclear fragmentation, whereas inhibitors of Jun kinase (SP 600125), MAP kinase (PD 98059), Src kinase (PP2) or PI-3 kinase (wortmannin) were without effect. Finally, immunoblot analysis of caspase-3 and PARP cleavage confirmed a role for activation of JAK2 in both HG- or ROS-induced apoptosis, based on inhibition by either AG-490 or adenoviral transfection with a dominant-negative JAK2 mutant. In conclusion the activation of JAK2 plays a pivotal role in oxidant stress-induced commitment of ECs to apoptosis, based on studies with HG and H(2)O(2).
authors.affiliation: Vascular Biology Center, Medical College of Georgia, Augusta, GA 30912, USA.
authors.forename: Amany
authors.initials: A
authors.lastname: Tawfik
authors.forename: Liming
authors.initials: L
authors.lastname: Jin
authors.forename: Amy K L
authors.initials: AK
authors.lastname: Banes-Berceli
authors.forename: Ruth B
authors.initials: RB
authors.lastname: Caldwell
authors.forename: Safia
authors.initials: S
authors.lastname: Ogbi
authors.forename: Amanda
authors.initials: A
authors.lastname: Shirley
authors.forename: Dwayne
authors.initials: D
authors.lastname: Barber
authors.forename: John D
authors.initials: JD
authors.lastname: Catravas
authors.forename: David M
authors.initials: DM
authors.lastname: Stern
authors.forename: David
authors.initials: D
authors.lastname: Fulton
authors.forename: R William
authors.initials: RW
authors.lastname: Caldwell
authors.forename: Mario B
authors.initials: MB
authors.lastname: Marrero
mesh_terms: D000256:Adenoviridae / Q000235:genetics; D001011:Aorta / Q000166:cytology / Q000502:physiology; D017209:Apoptosis / Q000502:physiology*; D015153:Blotting, Western; D002470:Cell Survival; D002478:Cells, Cultured; D042783:Endothelial Cells / Q000502:physiology* / Q000648:ultrastructure; D006801:Humans; D006861:Hydrogen Peroxide / Q000494:pharmacology; D006943:Hyperglycemia / Q000503:physiopathology*; D053614:Janus Kinase 2; D008856:Microscopy, Fluorescence; D009154:Mutation / Q000502:physiology; D011505:Protein-Tyrosine Kinases / Q000502:physiology*; D011518:Proto-Oncogene Proteins / Q000502:physiology*; D017382:Reactive Oxygen Species / Q000378:metabolism*; D015398:Signal Transduction / Q000502:physiology
chemical_list: D011518:Proto-Oncogene Proteins; D017382:Reactive Oxygen Species; D006861:Hydrogen Peroxide; D011505:Protein-Tyrosine Kinases; C507924:JAK2 protein, human; D053614:Janus Kinase 2