Deletion of p47phox attenuates the progression of diabetic nephropathy and reduces the severity of diabetes in the Akita mouse.
OBJECTIVE
Reactive oxygen species (ROS) contribute to diabetes-induced glomerular injury and endoplasmic reticulum (ER) stress-induced beta cell dysfunction, but the source of ROS has not been fully elucidated. Our aim was to determine whether p47(phox)-dependent activation of NADPH oxidase is responsible for hyperglycaemia-induced glomerular injury in the Akita mouse, a model of type 1 diabetes mellitus resulting from ER stress-induced beta cell dysfunction.


METHODS
We examined the effect of deleting p47 (phox) (also known as Ncf1), the gene for the NADPH oxidase subunit, on diabetic nephropathy in the Akita mouse (Ins2 (WT/C96Y)) by studying four groups of mice: (1) non-diabetic mice (Ins2 (WT/WT)/p47 (phox+/+)); (2) non-diabetic p47 (phox)-null mice (Ins2 (WT/WT)/p47 (phox-/-)); (3) diabetic mice: (Ins2 (WT/C96Y)/p47 (phox+/+)); and (4) diabetic p47 (phox)-null mice (Ins2 (WT/C96Y)/p47 (phox-/-)). We measured the urinary albumin excretion rate, oxidative stress, mesangial matrix expansion, and plasma and pancreatic insulin concentrations in 16-week-old mice; we also measured glucose tolerance and insulin sensitivity, islet and glomerular NADPH oxidase activity and subunit expression, and pro-fibrotic gene expression in 8-week-old mice. In addition, we measured NADPH oxidase activity, subunit expression and pro-fibrotic gene expression in high glucose-treated murine mesangial cells.


RESULTS
Deletion of p47 (phox) reduced kidney hypertrophy, oxidative stress and mesangial matrix expansion, and also reduced hyperglycaemia by increasing pancreatic and circulating insulin concentrations. p47 (phox-/-) mice exhibited improved glucose tolerance, but modestly decreased insulin sensitivity. Deletion of p47 (phox) attenuated high glucose-induced activation of NADPH oxidase and pro-fibrotic gene expression in glomeruli and mesangial cells.


CONCLUSIONS
Deletion of p47 (phox) attenuates diabetes-induced glomerular injury and beta cell dysfunction in the Akita mouse.
Institute of Medical Sciences, University of Toronto, 7326 Medical Sciences Building, 1 Kings College Circle, Toronto, ON M5S 1A8, Canada. chu.liu@utoronto.ca
G C
GC
Liu
F
F
Fang
J
J
Zhou
K
K
Koulajian
S
S
Yang
L
L
Lam
H N
HN
Reich
R
R
John
A M
AM
Herzenberg
A
A
Giacca
G Y
GY
Oudit
J W
JW
Scholey
D000818:Animals; D015153:Blotting, Western; D003921:Diabetes Mellitus, Experimental; D003922:Diabetes Mellitus, Type 1 / Q000235:genetics / Q000378:metabolism / Q000503:physiopathology*; D003928:Diabetic Nephropathies / Q000235:genetics / Q000378:metabolism / Q000503:physiopathology*; D018450:Disease Progression; D017353:Gene Deletion; D015971:Gene Expression Regulation, Enzymologic; D006943:Hyperglycemia / Q000235:genetics / Q000503:physiopathology*; D007678:Kidney Glomerulus / Q000293:injuries / Q000503:physiopathology*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D019255:NADPH Oxidases / Q000235:genetics / Q000378:metabolism*; D018384:Oxidative Stress; D017382:Reactive Oxygen Species / Q000378:metabolism*
D017382:Reactive Oxygen Species; D019255:NADPH Oxidases; C060505:neutrophil cytosolic factor 1