Molecular biological analysis of the role of LOX-1 and oxidative stress in the progressive renal diseases

2005 Fiscal Year Final Research Report Summary

• Project/Area Number: 16590778
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Kidney internal medicine
• Research Institution: The University of Tokyo
• Principal Investigator: KANAME Shinya The University of Tokyo, Faculty of Medicine, visiting associate professor, 医学部附属病院, 客員助教授 (60224581)
• Project Period (FY): 2004 – 2005
• Keywords: LOX-1 / adrenomedullin / oxidative stress / podocyte / puromycin

Research Abstract

We previously reported that adrenomedullin (AM), a vasoactive peptide belonging to the calcitonin-gene related peptide (CGRP) family, was expressed in murine podocyte cell lines (MPC) and was upregulated by various stimuli including puromycin (PAN). In this study, we examined the role of AM and oxidative stress in the development of PAN-induced podocyte injury. AM mRNA expression was analyzed by real-time PCR and oxidative stress was determined by ELISA for 8-OHdG, Western blot for nitrotyrosine and fluorescence study using CM-H_2DCFDA for reactive oxygen species (ROS) production. Apoptotic cells were detected by Hoechst33342 and caspase-3 staining. First, we showed that PAN caused an enhancement of oxidative stress markers and also an increase in apoptotic cell number, which was inhibited by antioxidants antimycin and diphenyleneiodium chloride (DPI), indicating that the PAN-induced apoptosis was mediated by enhanced oxidative stress. Because AM was shown to be induced by PAN, we next examined if AM had a protective or pathogenetic role in this condition. The result was that the PAN-induced oxidative stress and apoptosis were inhibited by addition of AM to the culture medium, and moreover, both were clearly exacerbated by blockade of AM action by treatment with an AM antagonist CGRP8-37. In summary, AM was induced by PAN in MPC via oxidative stress, causing an inhibitory effect on PAN-induced oxidative stress and apoptosis. These results suggest that AM may play a protective role as an endogenous regulator with anti-oxidative and anti-apoptotic action, mitigating the cell injury caused by PAN.

Research Products

• [Journal Article] Expression and regulation of adrenomedullin in renal glomerular podocytes. (2005)
  • Author(s): Hino M, Nagase M, Kaname S, Shibata S, Nagase T, Oba S, Funaki M, Kobayashi N, Kawachi H, Mundel P, Fujita T
  • Journal Title: Biochem Biophys Res Com 330 : 178-85, 2005. 330 Pages: 178-85
  • Description: 「研究成果報告書概要(和文)」より
• [Journal Article] Expression and regulation of adrenomedullin in renal glomerular podocytes. (2005)
  • Author(s): Hino M, Nagase M, Kaname S, Shibata S, Nagase T, Oba S, Funaki M, Kobayashi N, Kawachi H, Mundel P, Fujita T
  • Journal Title: Biochem Biophys Res Com 330 Pages: 178-185
  • Description: 「研究成果報告書概要(欧文)」より