title: Hepatic ischemic preconditioning in mice is associated with activation of NF-kappaB, p38 kinase, and cell cycle entry.
abstract: A brief period of hepatic ischemia protects the liver against subsequent ischemia-reperfusion (IR) injury, but the mechanism of such preconditioning is poorly understood. We examined whether preconditioning activated nuclear factor kappa B (NF-kappaB), the stress-activated protein kinases (SAPK), c-Jun N-terminal kinase-1 (JNK-1) and p38, and entry into the cell cycle. We used a murine model of partial hepatic ischemia. Preconditioning was performed by clamping the vasculature for 2 to 20 minutes, and allowing reperfusion for 10 minutes before 90-minute ischemia or IR. As assessed by serum alanine aminotransferase (ALT) levels and liver histology, preconditioning periods of 5 and 10 minutes were highly protective against IR injury, whereas 2-, 15-, and 20-minute intervals were ineffective. Preconditioning was associated with entry of hepatocytes into the cell cycle within 2 hours of subsequent IR, as indicated by proliferating cell nuclear antigen (PCNA) nuclear staining, induction of cyclin D1 and numerous mitotic figures; in the absence of preconditioning, such changes were not seen until 24 hours. Preconditioning increased nuclear binding of NF-kappaB within 30 minutes of the subsequent ischemic interval, paralleled by degradation of inhibitory (binding) protein for NF-kappaB (IkappaBalpha). Ischemic preconditioning also activated p38 kinase and JNK-1, which are known to converge on cyclin D1 regulation. The protective effect of the preconditioning regimen was more closely associated with p38 kinase than JNK-1 activation. In conclusion, the hepatoprotective effects of ischemic preconditioning are associated with activation of NF-kappaB and SAPKs that are associated with entry of hepatocytes into the cell cycle, a critical biological effect that favors survival of the liver against ischemic and IR injury.
authors.affiliation: Storr Liver Unit, Westmead Millennium Institute, University of Sydney at Westmead Hospital, Westmead, NSW 2145, Australia.
authors.forename: Narci
authors.initials: N
authors.lastname: Teoh
authors.forename: Aileen
authors.initials: A
authors.lastname: Dela Pena
authors.forename: Geoffrey
authors.initials: G
authors.lastname: Farrell
mesh_terms: D000818:Animals; D002453:Cell Cycle; D002467:Cell Nucleus / Q000737:chemistry / Q000378:metabolism; D019938:Cyclin D1 / Q000032:analysis / Q000096:biosynthesis; D003600:Cytosol / Q000737:chemistry; D005260:Female; D022781:Hepatocytes / Q000166:cytology; D019194:Ischemic Preconditioning; D008099:Liver / Q000098:blood supply* / Q000648:ultrastructure; D051379:Mice; D008810:Mice, Inbred C57BL; D048055:Mitogen-Activated Protein Kinase 8; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism*; D016328:NF-kappa B / Q000378:metabolism*; D018809:Proliferating Cell Nuclear Antigen / Q000032:analysis; D015427:Reperfusion Injury / Q000517:prevention & control; D048051:p38 Mitogen-Activated Protein Kinases
chemical_list: D016328:NF-kappa B; D018809:Proliferating Cell Nuclear Antigen; D019938:Cyclin D1; D048055:Mitogen-Activated Protein Kinase 8; D020928:Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases