ASN's Mission

ASN leads the fight to prevent, treat, and cure kidney diseases throughout the world by educating health professionals and scientists, advancing research and innovation, communicating new knowledge, and advocating for the highest quality care for patients.

learn more

Contact ASN

1401 H St, NW, Ste 900, Washington, DC 20005

email@asn-online.org

202-640-4660

The Latest on Twitter

Kidney Week

Abstract: TH-PO787

MAD2B-Medicated Cell Cycle Re-Entry of Podocytes Is Involved in the Pathogenesis of FSGS

Session Information

Category: Glomerular Diseases

  • 1201 Glomerular Diseases: Fibrosis and Extracellular Matrix

Authors

  • Bao, Dian, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, HUBEI, China
  • Su, Hua, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, HUBEI, China
  • Zhang, Chun, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, HUBEI, China
Background

Mitotic spindle assembly checkpoint protein 2 (MAD2B), an APC/C inhibitor, plays a pivotal role in cell cycle control. Previously, we reported that upregulation of MAD2B is involved in several renal diseases. However, the role and mechanism of MAD2B in the pathogenesis of focal segmental glomerulosclerosis (FSGS) is not known. In this study, we aimed to explore the role and mechanism of MAD2B in regulation podocyte cell cycle re-entry during FSGS.

Methods

Mouse FSGS model and conditionally immortalized human podocytes (HPCs) under puromycin aminonucleoside (PAN) treatment was utilized. Expression of MAD2B, APC/C complex regulatory molecules Cdh1, as well as its substrates cyclinB1, skp2, p27 and cyclinE1 was detected by western blot and immunohistochemistry. The cell cycle was analyzed by flow cytometry. Ki-67 and p-H3 expression was assessed by western blot and immunofluorescence. Knockdown of MAD2B was carried out by lentiviral shRNA transfection.Ku55933, a specific inhibitor of ATM kinase, was utilized. And PYR-41 was applied to interfere ubiquitination. CoIP was performed to assess the interaction between ATM and MAD2B.

Results

Comparing to control mice, the level of MAD2B in the glomeruli of FSGS mice is elevated dramatically. In PAN-treated HPCs, MAD2B deficiency attenuated the upregulation of p-H3, cyclinB1 and reversed Cdh1 reduction, which was companied by less cells staying in S-stage. Furthermore, pharmacological interference of ATM kinase activity in vitro ameliorated the accumulation of MAD2B with the less expression of p-H3 and Ki67 and the preservation of podocyte function presenting as increased podocin and CD2AP abundance. Finally, by using inhibitor targeting ubiquitinaton abolished the ATM kinase-mediated MAD2B regulation and subsequent cell cycle re-entry of podocytes, both in vitro and in vivo.

Conclusion

Overexpression of MAD2B is involved in the cell cycle re-entry and podocyte injury during FSGS, while ATM kinase-mediated posttranslational modification, especially ubiquitination is the potential upstream mechanism for MAD2B regulation.

Funding

  • Government Support - Non-U.S.