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: PO0710

Downregulation of Ehhadh and Tubular Dysfunction in Diabetic Nephropathy

Session Information

Category: Diabetic Kidney Disease

  • 601 Diabetic Kidney Disease: Basic

Authors

  • Zhong, Jianyong, Vanderbilt University Medical Center, Nashville, Tennessee, United States
  • Yang, Haichun, Vanderbilt University Medical Center, Nashville, Tennessee, United States
  • Harris, Raymond C., Vanderbilt University Medical Center, Nashville, Tennessee, United States
  • Fogo, Agnes B., Vanderbilt University Medical Center, Nashville, Tennessee, United States
Background

As a peroxisomal protein, enoyl-CoA hydratase and 3-hydroxyacyl CoA dehydrogenase (Ehhadh) catalyzes the second and third committed steps in the peroxisomal beta-oxidation pathway. Ehhadh also interacts with catalase and peroxisomal biogenesis factor 5 (PEX5), which decomposes hydrogen peroxide and regulates peroxisomal biogenesis, respectively. Previously we detected reduced tubular Ehhadh expression in human and mouse diabetic nephropathy. This study aims to investigate the potential impact of Ehhadh on peroxisomal/mitochondria functional change in response to high glucose in vitro.

Methods

Primary cultured proximal tubular epithelial cells (PTC) were exposed to high glucose, mannitol or control medium. Ehhadh subcellular localization and peroxisome quantitation (area per cell) were analyzed by confocal microscopy. Ehhadh, catalase, PEX5, ACOX1, Hsd17d4, scp2, ACAA1, cpt1a, Acadm, AHDHB, Acat1 and ACAA2 mRNA expression were assessed by qPCR. Peroxidase activity and oxidase stress were also analyzed.

Results

Ehhadh transcription and protein were significantly downregulated in PTC under high glucose conditions. Ehhadh was localized mostly to peroxisomes and rarely in mitochondria. Key enzymes for beta-oxidation in peroxisomes (ACOX1, Hsd17d4, scp2 and ACAA1) and mitochondria (cpt1a, Acadm, AHDHB, Acat1 and ACAA2) were not changed under high glucose conditions. Catalase transcription and peroxidase activity were reduced in high glucose vs control. PEX5 was also reduced, but peroxisome quantitation was increased 39.6% under high glucose conditions. Oxidative stress was also increased 7.6% in high glucose vs control.

Conclusion

Ehhadh downregulation is associated with reduced peroxidase activity, increased peroxisomal biogenesis and oxidative stress in PTC. Whether altering Ehhadh can impact such dysfunction awaits further study.

Funding

  • NIDDK Support