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Radovic, B.* ; Vujić, N.* ; Leopold, C.* ; Schlager, S.* ; Goeritzer, M.* ; Patankar, J.V.* ; Korbelius, M.* ; Kolb, D.* ; Reindl, J.* ; Wegscheider, M.* ; Tomin, T.* ; Birner-Gruenberger, R.* ; Schittmayer, M.* ; Groschner, L.* ; Magnes, C.* ; Diwoky, C.* ; Frank, S.* ; Steyrer, E.* ; Du, H.* ; Graier, W.F.* ; Madl, T. ; Kratky, D.*

Lysosomal acid lipase regulates VLDL synthesis and insulin sensitivity in mice.

Diabetologia 59, 1743-1752 (2016)
Verlagsversion DOI
Open Access Gold (Paid Option)
Creative Commons Lizenzvertrag
Aims/hypothesis: Lysosomal acid lipase (LAL) hydrolyses cholesteryl esters and triacylglycerols (TG) within lysosomes to mobilise NEFA and cholesterol. Since LAL-deficient (Lal-/-) mice suffer from progressive loss of adipose tissue and severe accumulation of lipids in hepatic lysosomes, we hypothesised that LAL deficiency triggers alternative energy pathway(s). Methods: We studied metabolic adaptations in Lal-/- mice. Results: Despite loss of adipose tissue, Lal-/- mice show enhanced glucose clearance during insulin and glucose tolerance tests and have increased uptake of [3H]2-deoxy-D-glucose into skeletal muscle compared with wild-type mice. In agreement, fasted Lal-/- mice exhibit reduced glucose and glycogen levels in skeletal muscle. We observed 84% decreased plasma leptin levels and significantly reduced hepatic ATP, glucose, glycogen and glutamine concentrations in fed Lal-/- mice. Markedly reduced hepatic acyl-CoA concentrations decrease the expression of peroxisome proliferator-activated receptor α (PPARα) target genes. However, treatment of Lal-/- mice with the PPARα agonist fenofibrate further decreased plasma TG (and hepatic glucose and glycogen) concentrations in Lal-/- mice. Depletion of hepatic nuclear factor 4α and forkhead box protein a2 in fasted Lal-/- mice might be responsible for reduced expression of microsomal TG transfer protein, defective VLDL synthesis and drastically reduced plasma TG levels. Conclusions/interpretation: Our findings indicate that neither activation nor inactivation of PPARα per se but rather the availability of hepatic acyl-CoA concentrations regulates VLDL synthesis and subsequent metabolic adaptations in Lal-/- mice. We conclude that decreased plasma VLDL production enhances glucose uptake into skeletal muscle to compensate for the lack of energy supply.
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Publikationstyp Artikel: Journalartikel
Dokumenttyp Wissenschaftlicher Artikel
Schlagwörter Glucose Tolerance ; Lipolysis ; Lysosomes ; Vldl
ISSN (print) / ISBN 0012-186X
e-ISSN 1432-0428
Zeitschrift Diabetologia
Quellenangaben Band: 59, Heft: 8, Seiten: 1743-1752 Artikelnummer: , Supplement: ,
Verlag Springer
Verlagsort Berlin ; Heidelberg [u.a.]
Begutachtungsstatus Peer reviewed