Abstract
Serum levels of leukotriene-B4 (LTB4) are increased in type 1 diabetes (T1D) and it mediates systemic inflammation and macrophage reprogramming associated with this condition. Herein, we investigated the involvement of LTB4 in adiposity loss, hyperlipidemia, and changes in macrophage metabolism in a mouse model of streptozotocin-induced T1D. LTB4 receptor (BLT1) antagonist u75302 was employed to block LTB4 effects. As expected, hypoinsulinemia in T1D was associated with hyperglycemia, low levels of glucagon, hyperlipidemia, significant body fat loss, and increased white adipose tissue expression of Fgf21, a marker for lipolysis. With the exception of hyperglycemia and hypoglucagonemia, blockade of LTB4 signaling reverted these parameters in T1D mice. Along with hyperlipidemia, macrophages from T1D mice exhibited higher lipid uptake and accumulation. These cells also had enhanced glycolysis and oxidative metabolism and these parameters were dependent on the mitochondrial uncoupling respiration, as evidenced by elevated expression of oxidation markers carnitine palmitoyltransferase and uncoupling protein 1. Interestingly, all these parameters were at least partially reverted in T1D mice treated with u75302. Altogether, these findings suggest that in T1D mice LTB4/BLT1 is involved in the fat loss, hyperlipidemia, and increased macrophage lipid uptake and metabolism with an important involvement of mitochondrial uncoupling activity. These previously unrecognized LTB4/BLT1 functions may be explored in future to therapeutically alleviate severity of hyperlipidemia and systemic inflammation in T1D.
Original language | English (US) |
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Pages (from-to) | 665-675 |
Number of pages | 11 |
Journal | Journal of Leukocyte Biology |
Volume | 106 |
Issue number | 3 |
DOIs | |
State | Published - Sep 2019 |
Externally published | Yes |
Keywords
- Adiposity/drug effects
- Animals
- Biomarkers/metabolism
- Diabetes Mellitus, Type 1/metabolism
- Down-Regulation/drug effects
- Energy Metabolism/drug effects
- Fatty Acids/metabolism
- Glycolysis/drug effects
- Hyperlipidemias/metabolism
- Leukotriene B4/pharmacology
- Lipogenesis/drug effects
- Liver/drug effects
- Macrophages, Peritoneal/drug effects
- Male
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- Oxidation-Reduction/drug effects
- Signal Transduction/drug effects
- Uncoupling Protein 1/metabolism