measurement-energy-metabolism-explanted-retinal-tissue-using

Measurement of Energy Metabolism in Explanted Retinal Tissue Using Extracellular Flux Analysis

High acuity vision is a heavily energy-consuming process, and the retina has developed several unique adaptations to precisely meet such demands while ...

Washington University School of Medicine

Fatty acid synthase (FAS) is altered in metabolic disorders and cancer. Conventional FAS null mice die in utero, so effects of whole-body inhibition of lipogenesis following development are unknown. Inducible global knockout of FAS (iFASKO) in mice was lethal due to a disrupted intestinal barrier and leukopenia. Conditional loss of FAS was associated with the selective suppression of granulopoiesis without disrupting granulocytic differentiation. Transplantation of iFASKO bone marrow into wild-type mice followed by Cre induction resulted in selective neutrophil depletion, but not death. Impaired lipogenesis increased ER stress and apoptosis in neutrophils by preferentially decreasing peroxisome-derived membrane phospholipids containing ether bonds. Inducible global knockout of PexRAP, a peroxisomal enzyme required for ether lipid synthesis, also produced neutropenia. FAS knockdown in neutrophil-like HL-60 cells caused cell loss that was partially rescued by ether lipids. Inhibiting ether lipid synthesis selectively constrains neutrophil development, revealing an unrecognized pathway in immunometabolism. 

Peroxisomal lipid synthesis regulates inflammation by sustaining neutrophil membrane phospholipid composition and viability.

Acute ether lipid deficiency affects neutrophil biology in mice.

Diabetes is a disorder of abnormal lipid metabolism, a notion strongly supported by the work of Edwin Bierman, for whom this eponymous lecture is named. This abnormal lipid environment continues to be associated with devastating vascular complications in diabetes despite current therapies, suggesting that our understanding of the pathophysiology of blood vessel disease in diabetes is limited. In this review, potential new insights into the nature of diabetic vasculopathy will be discussed. Recent observations suggest that while the concept of distinct macrovascular and microvascular complications of diabetes has been useful, vascular diseases in diabetes may be more interrelated than previously appreciated. Moreover, the intermediary metabolic pathway of de novo lipogenesis, which synthesizes lipids from simple precursors, is robustly sensitive to insulin and may contribute to these complications. De novo lipogenesis requires fatty acid synthase, and recent studies of this enzyme suggest that endogenously produced lipids are channeled to specific intracellular sites to affect physiology. These findings raise the possibility that novel approaches to treating diabetes and its complications could be based on altering the intracellular lipid milieu.

Clay F. Semenkovich

Division of Metabolism,
Endocrinology and Lipid Research,
Department of Medicine,
Division of Metabolism, Endocrinology and Lipid Research, Department of Medicine

Washington University School of Medicine

Measurement of Energy Metabolism in Explanted Retinal Tissue Using Extracellular Flux Analysis

Clay F. Semenkovich

.css-o250i3{font-size:18px;font-family:Open Sans,sans-serif;line-height:21.6px;}Division of Metabolism,Endocrinology and Lipid Research,Department of Medicine,Division of Metabolism, Endocrinology and Lipid Research, Department of Medicine

Washington University School of Medicine

Measurement of Energy Metabolism in Explanted Retinal Tissue Using Extracellular Flux Analysis

Division of Metabolism,
Endocrinology and Lipid Research,
Department of Medicine,
Division of Metabolism, Endocrinology and Lipid Research, Department of Medicine