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Ablation of Adipose-HO-1 Expression Increases White Fat over Beige Fat Through Inhibition of Mitochondrial Fusion and of PGC1alpha in Female Mice
Hormone Molecular Biology and Clinical Investigation
  • S Singh
  • I Grant
  • A Meissner
  • A Kappas
  • Nader Abraham, New York Medical College
Document Type
Article
Publication Date
8-1-2017
Department
Medicine
Abstract

Background Hmox1 plays an important role in the regulation of mitochondrial bioenergetics and function by regulating cellular heme-derived CO and bilirubin. Previous studies have demonstrated that global disruption of HO-1 in humans and mice resulted in severe organ dysfunction. Methods We investigated the potential role of adipose-specific-HO-1 genetic ablation on adipose tissue function, mitochondrial quality control and energy expenditure by generating an adipo-HO-1 knockout mouse model (Adipo-HO-1-/-) and, in vitro, adipocyte cells in which HO activity was inhibited. Adiposity, signaling proteins, fasting glucose and oxygen consumption were determined and compared to adipocyte cultures with depressed levels of both HO-1/HO-2. Results Adipo-HO-1-/- female mice exhibited increased adipocyte size, and decreases in the mitochondrial fusion to fission ratio, PGC1, and SIRT3. Importantly, ablation of HO-1 in adipose tissue resulted in fat acquiring many properties of visceral fat such as decreases in thermogenic genes including pAMPK and PRDM16. Deletion of HO-1 in mouse adipose tissue led to complete metabolic dysfunction, an increase in white adipose tissue, a reduction of beige fat and associated increases in FAS, aP2 and hyperglycemia. Mechanistically, genetic deletion of HO-1 in adipose tissues decreased the mitochondrial fusion to fission ratio; disrupted the activity of the PGC1 transcriptional axis and thermogenic genes both in vitro and in vivo. Conclusion Ablation of adipose tissue-HO-1 abridged PGC1 expression promoted mitochondrial dysfunction and contributed to an increase of pro-inflammatory visceral fat and abrogated beige-cell like phenotype.

Creative Commons License
Creative Commons Attribution-NonCommercial-No Derivative Works 4.0 International
Citation Information
S Singh, I Grant, A Meissner, A Kappas, et al.. "Ablation of Adipose-HO-1 Expression Increases White Fat over Beige Fat Through Inhibition of Mitochondrial Fusion and of PGC1alpha in Female Mice" Hormone Molecular Biology and Clinical Investigation Vol. 31 Iss. 1 (2017)
Available at: http://works.bepress.com/nader_abraham/50/