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ID 119320
Title Alternative
Miox in Obesity
Author
Dutta, Rajesh K. Northwestern University
Joladarashi, Darukeshwara Northwestern University
Reddy, Janardan K. Northwestern University
Kanwar, Yashpal S. Northwestern University
Content Type
Journal Article
Description
The kidney is one of the target organs for various metabolic diseases, including diabetes, metabolic syndrome, and obesity. Most of the metabolic studies underscore glomerular pathobiology, although the tubulo-interstitial compartment has been underemphasized. This study highlights mechanisms concerning the pathobiology of tubular injury in the context of myoinositol oxygenase (Miox), a tubular enzyme. The kidneys of mice fed a high fat diet (HFD) had increased Miox expression and activity, and the latter was related to phosphorylation of serine/threonine residues. Also, expression of sterol regulatory element-binding protein1 (Srebp1) and markers of cellular/nuclear damage was increased along with accentuated apoptosis and loss of tubular brush border. Similar results were observed in cells treated with palmitate/BSA. Multiple sterol-response elements and E-box motifs were found in the miox promoter, and its activity was modulated by palmitate/BSA. Electrophoretic mobility and ChIP assays confirmed binding of Srebp to consensus sequences of the miox promoter. Exposure of palmitate/BSA-treated cells to rapamycin normalized Miox expression and prevented Srebp1 nuclear translocation. In addition, rapamycin treatment reduced p53 expression and apoptosis. Like rapamycin, srebp siRNA reduced Miox expression. Increased expression of Miox was associated with the generation of reactive oxygen species (ROS) in kidney tubules of mice fed an HFD and cell exposed to palmitate/BSA. Both miox and srebp1 siRNAs reduced generation of ROS. Collectively, these findings suggest that HFD or fatty acids modulate transcriptional, translational, and post-translational regulation of Miox expression/activity and underscore Miox being a novel target of the transcription factor Srebp1. Conceivably, activation of the mTORC1/Srebp1/Miox pathway leads to the generation of ROS culminating into tubulo-interstitial injury in states of obesity.
Journal Title
Journal of Biological Chemistry
ISSN
00219258
1083351X
NCID
AA1202441X
Publisher
American Society for Biochemistry and Molecular Biology|Elsevier
Volume
291
Issue
3
Start Page
1348
End Page
1367
Published Date
2015-11-17
Rights
This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).
EDB ID
DOI (Published Version)
URL ( Publisher's Version )
FullText File
language
eng
TextVersion
Publisher
departments
Medical Sciences