MAD2B contributes to podocyte injury of diabetic nephropathy via inducing cyclin B1 and Skp2 accumulation

Am J Physiol Renal Physiol. 2015 Apr 1;308(7):F728-36. doi: 10.1152/ajprenal.00409.2014. Epub 2015 Jan 28.

Abstract

It is well documented that mitotic arrest deficiency (MAD)2B can inhibit the anaphase-promoting complex/cyclosome (APC/C) via cadherin (Cdh)1 and, consequently, can destroy the effective mitotic spindle checkpoint control. Podocytes have been observed to rapidly detach and die when being forced to bypass cell cycle checkpoints. However, the role of MAD2B, a cell cycle regulator, in podocyte impairment of diabetic nephropathy (DN) is unclear. In the present study, we investigated the significance of MAD2B in the pathogenesis of DN in patients, an animal model, and in vitro podocyte cultures. By Western blot and immunohistochemistry analyses, we found that MAD2B was evidently upregulated under high glucose milieu in vivo and in vitro, whereas Cdh1 was inhibited with high glucose exposure. Overexpression of MAD2B in podocytes by plasmid DNA transfection suppressed expression of Cdh1 and triggered the accumulation of cyclin B1 and S phase kinase-associated protein (Skp)2, two key molecules involving in cell cycle regulation, and the subsequent podocyte insult. In contrast, MAD2B deletion alleviated the high glucose-induced reduction of Cdh1 as well as the elevation of cyclin B1 and Skp2, which rescued the podocyte from damage. Taken together, our data demonstrate that MAD2B may play an important role in high glucose-mediated podocyte injury of DN via modulation of Cdh1, cyclin B1, and Skp2 expression.

Keywords: S phase kinase-associated protein 2; cyclin B1; diabetic nephropathy; mitotic arrest deficiency 2B; podocytes.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Anaphase-Promoting Complex-Cyclosome / metabolism
  • Animals
  • Cdh1 Proteins / metabolism
  • Cell Cycle Proteins / metabolism
  • Cell Nucleus / metabolism
  • Cyclin B1 / metabolism*
  • Diabetic Nephropathies / metabolism*
  • Diabetic Nephropathies / pathology
  • Humans
  • Mad2 Proteins / metabolism*
  • Mice, Inbred C57BL
  • Mitosis / physiology
  • Podocytes / metabolism*
  • Rats, Sprague-Dawley
  • Rats, Wistar
  • S-Phase Kinase-Associated Proteins / metabolism*

Substances

  • Cdh1 Proteins
  • Cell Cycle Proteins
  • Cyclin B1
  • Mad2 Proteins
  • S-Phase Kinase-Associated Proteins
  • Anaphase-Promoting Complex-Cyclosome