Up-regulation of hepatic lipolysis stimulated lipoprotein receptor by leptin: a potential lever for controlling lipid clearance during the postprandial phase.
As a hepatic receptor for triglyceride-rich lipoproteins, the lipolysis-stimulated lipoprotein receptor (LSR) may be involved in the dynamics of lipid distribution between the liver and peripheral tissues. Here, we explore the potential role of leptin in regulating LSR. At physiological concentrations (1-10 ng/ml), leptin increased LSR protein and mRNA levels in Hepa1-6 cells through an ERK1/2-dependent and α-amanitin-sensitive pathway. In vivo, leptin treatment of C57BL6/Rj mice (1 μg 2×/d, 8 d) led to a significant increase in hepatic LSR mRNA and protein, decreased liver triglycerides and increased VLDL secretion as compared to controls. LSR(+/-) mice with elevated postprandial lipemia placed on a high-fat (60% kcal) diet exhibited accelerated weight gain and increased fat mass as compared to controls. While plasma leptin levels were increased 3-fold, hepatic leptin receptor protein levels and phosphorylation of ERK1/2 were significantly reduced. Therefore, leptin is an important regulator of LSR protein levels providing the means for the control of hepatic uptake of lipids during the postprandial phase. However, this may no longer be functional in LSR(+/-) mice placed under a chronic dietary fat load, suggesting that this animal model could be useful for the study of molecular mechanisms involved in peripheral leptin resistance.
Stenger
Christophe
C
Lipidomix, Nancy University, Institut National Polytechnique de Lorraine-Ecole Nationale Supérieure d'Agronomie et des Industries Alimentaires (INPL ENSAIA), Vandoeuvre-lès-Nancy, France.
Hanse
Marine
M
Pratte
Dagmar
D
Mbala
Marie-Ludvine
ML
Akbar
Samina
S
Koziel
Violette
V
Escanyé
Marie-Christine
MC
Kriem
Badreddine
B
Malaplate-Armand
Catherine
C
Olivier
Jean-Luc
JL
Oster
Thierry
T
Pillot
Thierry
T
Yen
Frances T
FT
D000818:Animals; D015153:Blotting, Western; D001835:Body Weight / Q000187:drug effects; D002460:Cell Line; D005455:Fluorescent Antibody Technique; D020738:Leptin / Q000097:blood / Q000494:pharmacology*; D050356:Lipid Metabolism / Q000187:drug effects*; D008066:Lipolysis / Q000187:drug effects*; D008099:Liver / Q000187:drug effects* / Q000378:metabolism; D051379:Mice; D008810:Mice, Inbred C57BL; D016133:Polymerase Chain Reaction; D019518:Postprandial Period; D018110:Receptors, Lipoprotein / Q000378:metabolism*; D015854:Up-Regulation / Q000187:drug effects*
D020738:Leptin; D018110:Receptors, Lipoprotein