Deficiency in Apoptosis-Inducing Factor Recapitulates Chronic Kidney Disease via Aberrant Mitochondrial Homeostasis.

Abstract

Apoptosis-inducing factor (AIF) is a mitochondrial flavoprotein with dual roles in redox signaling and programmed cell death. Deficiency in AIF is known to result in defective oxidative phosphorylation (OXPHOS), via loss of complex I activity and assembly in other tissues. Because the kidney relies on OXPHOS for metabolic homeostasis, we hypothesized that a decrease in AIF would result in chronic kidney disease (CKD). Here, we report that partial knockdown of Aif in mice recapitulates many features of CKD, in association with a compensatory increase in the mitochondrial ATP pool via a shift toward mitochondrial fusion, excess mitochondrial reactive oxygen species production, and Nox4 upregulation. However, despite a 50% lower AIF protein content in the kidney cortex, there was no loss of complex I activity or assembly. When diabetes was superimposed onto Aif knockdown, there were extensive changes in mitochondrial function and networking, which augmented the renal lesion. Studies in patients with diabetic nephropathy showed a decrease in AIF within the renal tubular compartment and lower AIFM1 renal cortical gene expression, which correlated with declining glomerular filtration rate. Lentiviral overexpression of Aif1m rescued glucose-induced disruption of mitochondrial respiration in human primary proximal tubule cells. These studies demonstrate that AIF deficiency is a risk factor for the development of diabetic kidney disease.

• Authors: Melinda T Coughlan, Gavin C Higgins, Tuong-Vi Nguyen, Sally A Penfold, Vicki Thallas-Bonke, Sih Min Tan, Georg Ramm, Nicole J Van Bergen, Darren C Henstridge, Karly C Sourris, Brooke E Harcourt, Ian A Trounce, Portia M Robb, Adrienne Laskowski, Sean L McGee, Amanda J Genders, Ken Walder, Brian G Drew, Paul Gregorevic, Hongwei Qian, Merlin C Thomas, George Jerums, Richard J Macisaac, Alison Skene, David A Power, Elif I Ekinci, Xiaonan W Wijeyeratne, Linda A Gallo, Michal Herman-Edelstein, Michael T Ryan, Mark E Cooper, David R Thorburn, Josephine M Forbes
• Journal: Diabetes (Diabetes) Vol. 65 Issue 4 Pg. 1085-98 (04 2016) ISSN: 1939-327X [Electronic] United States
• PMID: 26822084 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
• Copyright: © 2016 by the American Diabetes Association. Readers may use this article as long as the work is properly cited, the use is educational and not for profit, and the work is not altered.

Chemical References

• Apoptosis Inducing Factor
• AIFM1 protein, mouse

Topics

• Animals
• Apoptosis Inducing Factor (genetics)
• Cell Respiration (genetics)
• Cells, Cultured
• Diabetes Mellitus, Experimental (complications, genetics, metabolism)
• Diabetic Nephropathies (genetics, metabolism)
• Genetic Predisposition to Disease
• Homeostasis (genetics)
• Humans
• Male
• Mice
• Mice, Inbred C57BL
• Mice, Inbred CBA
• Mice, Transgenic
• Mitochondria (metabolism)
• Oxidative Phosphorylation
• Renal Insufficiency, Chronic (genetics, metabolism)
• Risk Factors