Abstract: TH-PO675

NADPH-Oxidase NOX5 Aggravates Renal Injury in Human Diabetic Nephropathy

Session Information

Category: Diabetes

  • 501 Diabetes Mellitus and Obesity: Basic - Experimental

Authors

  • Jha, Jay Chandra, Monash University, Melbourne, Victoria, Australia
  • Coughlan, Melinda T., Monash University, Melbourne, Victoria, Australia
  • Power, David A., Austin Health, Heidelberg, New South Wales, Australia
  • Kennedy, Chris R., Kidney Research Centre, Ottawa, Ontario, Canada
  • Cooper, Mark E., Monash University, Melbourne, Victoria, Australia
  • Jandeleit-Dahm, Karin, Monash University, Melbourne, Victoria, Australia
Background

Renal oxidative stress plays an important role in mediating kidney injury in diabetes. There is increasing evidences that recently discovered pro-oxidant enzyme, Nox5 plays a significant role in human diabetic nephropathy (DN). Nox5 is present in humans and rabbits but not in mice or rats. Thus, there is a paucity of information about Nox5 in conventional animal models of DN. We examined the role of Nox5 in human diabetic nephropathy, in human renal cell populations as well as in a high fat fed rabbit model of kidney disease.

Methods

Protein expression of Nox5 and its localization in glomerular cells (podocytes and mesangial cells) and tubular cells were examined by immunostaining in human kidney biopsies obtained from non-diabetic and diabetic individuals. In vitro, human mesangial cells, podocytes and proximal tubules were exposed to high glucose, TGF-β and AngII and Nox5 was knockdown in these renal cells. Cell morphology, gene and protein expression of markers of fibrosis and inflammation as well as putative signalling pathways and the level of ROS were assessed in these human renal cells. We also examined expression of pro-fibrotic gene in high fat fed rabbits by next generation sequencing (NGS) and RT-PCR and renal injury by histochemistry.

Results

Expression of Nox5 was increased in both glomerular and tubular compartments of kidney biopsies obtained from diabetic individuals when compared to non-diabetic individuals. In addition, silencing of Nox5 in human renal cells resulted in reduced ROS production and decreased expression of pro-fibrotic and pro-inflammatory markers as well as putative elements that are implicated in DN. Moreover, increased expression of Nox5 in high fat fed rabbits versus normal diet fed rabbits was associated with increased expression of fibronectin, CTGF, collagen IV and VCAM-1 as well as increased mesangial expansion in the kidney.

Conclusion

These findings suggest that Nox5 accelerates renal injury in diabetes and provide proof of principle for the development of a new renoprotective agent in diabetes.