Project title
血基質氧化酵素-1 調節腹膜表面細胞衰老的角色---腹膜硬化症的機轉
Internal ID
NSC100-2314-B002-126
Principal Investigator
Start Date
August 1, 2011
End Date
July 12, 2012
Partner Organizations
Project Web Site
Role of Heme Oxygenase-1 (HO-2) in Regulation of Peritoneal Mesothelial Cell Senescence---Mechanism of Peritoneal Fibrosis = 血基質氧化酵素-1 調節腹膜表面細胞衰老的角色---腹膜硬化症的機轉
Description
We had studied for years focusing on the management of peritoneal fibrosis. We had identified that the un-physiological peritoneal dialysis (PD) solutions may induce oxidative stress, chronic inflammatory reaction within the peritoneal cavity. We also had documented that hemoperitoneum occurs not infrequently in PD patients, and may induce peritoneal fibrosis through oxidative stress and ferritin reaction (97-2314-B-002-053-MY3, paper submitted). In this proposal we will investigate the role of heme oxygenase-1 (HO) and ferritin heavy chain in cellular senescence of cultured human omentum-derived peritoneal mesothelial cells. In the first year, we checked the hypothesis that during cellular senescence free radical may accumulate and therefore HO-1 may also be induced. Induction of the enzyme is protective for the cell from rapid progression of senescence. We will characterize the expression pattern of HO-1 alteration during the senescence course of cultured human peritoneal mesothelial cells. To study their role in deterring cellular senescence, we will use RNA interference to knock down expression of each gene. Studies have supported that aging is associated with the consequence of free radical damage by various endogenous reactive oxygen species. In the second year project, we will study further the free radical induction of HO-1 expression, which may further cause generation of ferritin heavy chain. We also aim to study the alteration of senescence- and aging-related markers, including population doubling number, p16-INK4a, p66shc, Sirt1, FoxO, Klotho, Werner syndrome protein WNR, and mTOR signaling will be examined. Telomere length, autophagy marker LC3, oxidative stress marker 8-hydroxydeoxyguanosine and Fe (II) to Fe (III) ratio will be measured as well. To further support our hypothesis, in the third year, we also attempt to over-express HO-1 into the cultured cells by introducing an expression vector carrying HO-1 full-length cDNA, and analyze the senescence phenotypes. To test the hypothesis that ferritin heavy chain is a down stream effector of HO-1, we will introduce ferritin heavy chain expression vector into the cells that bear HO-1 interference RNA. If HO-1 knock-down cells can have then a slower pace of senescence when they are forced to express ferritin heavy chain, it will support the hypothesis. Through this 3-year project, together with the previous 3-year NSC project (97-2314-B-002-053-MY3, paper submitted), we can measure directly what really happen in sub-clinical PD patients, and answer one important but unanswered question: “Why uneventful PD patients will get PF at the end of long-term PD therapy?” In summary, Our findings can be a big jump by making clear the HO-1 and ferritin heavy chain serving as protectors of cellular senescence. And our proposal will provide value as an important basis for future translational research and give a better view in this uncharted territory.