Lecithin:Cholesterol Acyltransferase (LCAT) Deficiency Promotes Differentiation of Satellite Cells to Brown Adipocytes in a Cholesterol-dependent Manner.
Our laboratory previously reported that lecithin:cholesterol acyltransferase (LCAT) and LDL receptor double knock-out mice (Ldlr(-/-)xLcat(-/-) or DKO) spontaneously develop functioning ectopic brown adipose tissue (BAT) in skeletal muscle, putatively contributing to protection from the diet-induced obesity phenotype. Here we further investigated their developmental origin and the mechanistic role of LCAT deficiency. Gene profiling of skeletal muscle in DKO newborns and adults revealed a classical lineage. Primary quiescent satellite cells (SC) from chow-fed DKO mice, not in Ldlr(-/-)xLcat(+/+) single-knock-out (SKO) or C57BL/6 wild type, were found to (i) express exclusively classical BAT-selective genes, (ii) be primed to express key functional BAT genes, and (iii) exhibit markedly increased ex vivo adipogenic differentiation into brown adipocytes. This gene priming effect was abrogated upon feeding the mice a 2% high cholesterol diet in association with accumulation of excess intracellular cholesterol. Ex vivo cholesterol loading of chow-fed DKO SC recapitulated the effect, indicating that cellular cholesterol is a key regulator of SC-to-BAT differentiation. Comparing adipogenicity of Ldlr(+/+)xLcat(-/-) (LCAT-KO) SC with DKO SC identified a role for LCAT deficiency in priming SC to express BAT genes. Additionally, we found that reduced cellular cholesterol is important for adipogenic differentiation, evidenced by increased induction of adipogenesis in cholesterol-depleted SC from both LCAT-KO and SKO mice. Taken together, we conclude that ectopic BAT in DKO mice is classical in origin, and its development begins in utero. We further showed complementary roles of LCAT deficiency and cellular cholesterol reduction in the SC-to-BAT adipogenesis.
From the Keenan Research Centre, Li Ka Shing Knowledge Institute, Department of Medicine, St. Michael's Hospital, Toronto, Ontario M5B 1W8, Canada and the Department of Physiology, Faculty of Medicine, and.
Dinushan
D
Nesan
From the Keenan Research Centre, Li Ka Shing Knowledge Institute, Department of Medicine, St. Michael's Hospital, Toronto, Ontario M5B 1W8, Canada and.
Ghazaleh
G
Tavallaee
From the Keenan Research Centre, Li Ka Shing Knowledge Institute, Department of Medicine, St. Michael's Hospital, Toronto, Ontario M5B 1W8, Canada and.
Deborah
D
Koh
From the Keenan Research Centre, Li Ka Shing Knowledge Institute, Department of Medicine, St. Michael's Hospital, Toronto, Ontario M5B 1W8, Canada and the Department of Physiology, Faculty of Medicine, and.
Amir
A
Bashiri
From the Keenan Research Centre, Li Ka Shing Knowledge Institute, Department of Medicine, St. Michael's Hospital, Toronto, Ontario M5B 1W8, Canada and.
Rawand
R
Abdin
From the Keenan Research Centre, Li Ka Shing Knowledge Institute, Department of Medicine, St. Michael's Hospital, Toronto, Ontario M5B 1W8, Canada and the Department of Physiology, Faculty of Medicine, and Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario M5S 1A8, Canada ngd@smh.ca.
Dominic S
DS
Ng
D052437:Adipocytes, Brown / Q000378:metabolism* / Q000473:pathology; D050156:Adipogenesis; D000818:Animals; D002454:Cell Differentiation; D002784:Cholesterol / Q000235:genetics / Q000378:metabolism*; D007863:Lecithin Cholesterol Acyltransferase Deficiency / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D051379:Mice; D018345:Mice, Knockout; D032496:Satellite Cells, Skeletal Muscle / Q000378:metabolism* / Q000473:pathology
D002784:Cholesterol
LCAT; animal model; brown adipose tissue; cholesterol; differentiation; metabolic regulation; obesity; satellite cells; uncoupling protein 1