Impact of early onset obesity and hypertension on the unfolded protein response in renal tissues of juvenile sheep.
Childhood obesity has reached epidemic proportions. Obesity is an independent risk factor for the development of end-stage renal disease. Endoplasmic reticulum stress and subsequent activation of the unfolded protein response (UPR) are implicated in the development of adipose tissue dysregulation and type 2 diabetes mellitus in obesity. The present study explored the impact of adolescent-onset obesity on the UPR after obesity-related hypertension and nephropathy, using an ovine model in which obesity was induced by increased food intake and reduced activity. Obese young adults had a higher mean arterial pressure (lean, 89.6+/-1.7 mm Hg versus obese, 101+/-3.0 mm Hg; P<0.01) and greater sensitivity to low physiological doses of angiotensin II. Obesity increased the glomerular area and was associated with activation of the UPR in renal cells with a greater abundance of glucose-regulated protein 78, C/EBP homologous protein, Bax, phosphorylated c-Jun amino-terminal kinase, and activating transcription factor 6 (all P<0.05). In addition, there was a marked upregulation of proinflammatory genes, most notably those involved in macrophage signaling. Reactive oxygen species production and handling were also perturbed in obese adults. Renal endoplasmic reticulum stress was positively correlated with macrophage content (r=0.83; P<0.001), phosphorylated c-Jun amino-terminal kinase (r=0.73; P<0.01), and adiposity (r=0.71; P<0.01). In conclusion, adolescent-onset, obesity-related renal endoplasmic reticulum stress was associated with activation of the UPR, apoptosis, and inflammation, potentially increasing the associated renal damage observed in young adults. The UPR may prove to be a useful therapeutic target for the treatment and prevention of obesity-related nephropathy and associated hypertension, thereby reducing the burden of end-stage renal disease.
Sharkey
Don
D
Centre for Reproduction and Early Life, Institute of Clinical Research, University of Nottingham, Nottingham, United Kingdom.
Fainberg
Hernan P
HP
Wilson
Vicky
V
Harvey
Emma
E
Gardner
David S
DS
Symonds
Michael E
ME
Budge
Helen
H
D000704:Analysis of Variance; D000804:Angiotensin II / Q000494:pharmacology; D000818:Animals; D000831:Animals, Newborn; D015153:Blotting, Western; D004195:Disease Models, Animal; D018450:Disease Progression; D005260:Female; D006973:Hypertension / Q000150:complications*; D007150:Immunohistochemistry; D007668:Kidney / Q000378:metabolism / Q000473:pathology*; D007674:Kidney Diseases / Q000209:etiology / Q000473:pathology; D008297:Male; D009569:Nitric Oxide / Q000378:metabolism; D009765:Obesity / Q000150:complications*; D011506:Proteins / Q000378:metabolism*; D012333:RNA, Messenger / Q000032:analysis; D011897:Random Allocation; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012680:Sensitivity and Specificity; D012756:Sheep; D018709:Statistics, Nonparametric; D046509:Tissue Culture Techniques
D011506:Proteins; D012333:RNA, Messenger; D000804:Angiotensin II; D009569:Nitric Oxide