title: Adipose triglyceride lipase (ATGL) expression in human skeletal muscle is type I (oxidative) fiber specific.
abstract: Accumulation of triacylglycerol (TAG) and lipid intermediates in skeletal muscle plays an important role in the etiology of insulin resistance and type 2 diabetes mellitus. Disturbances in skeletal muscle lipid turnover and lipolysis may contribute significantly to this. So far, knowledge on the regulation of muscle lipolysis is limited. Recently the identification of a new lipase was reported: adipose triglyceride lipase (ATGL). ATGL deficient animals show significant lipid accumulation in skeletal muscle, which may indicate that ATGL plays a pivotal role in skeletal muscle lipolysis. However, until now, it is still unknown whether ATGL protein is expressed in human skeletal muscle. Therefore, the aim of the present study was to investigate whether ATGL is expressed at the protein level in human skeletal muscle, and to examine whether its expression is fiber-type specific. To accomplish this, we established an imunohistochemical and immunofluorescent staining procedure to study ATGL protein expression in relation to fiber type in human vastus lateralis muscle of eight male subjects (BMI range: 21.0-34.5 kg/m2 and age: 38-59 years). In the present paper we report for the first time that ATGL protein is indeed expressed in human skeletal muscle. Moreover, ATGL is exclusively expressed in type I (oxidative) muscle fibers, suggesting a pivotal role for ATGL in intramuscular fatty acid handling, lipid storage and breakdown.
authors.affiliation: Department of Human Biology, Nutrition and Toxicology Research Institute Maastricht, Maastricht University, PO Box 616, 6200 MD Maastricht, The Netherlands. J.Jocken@HB.unimaas.nl
authors.forename: Johan W E
authors.initials: JW
authors.lastname: Jocken
authors.forename: Egbert
authors.initials: E
authors.lastname: Smit
authors.forename: Gijs H
authors.initials: GH
authors.lastname: Goossens
authors.forename: Yvonne P G
authors.initials: YP
authors.lastname: Essers
authors.forename: Marleen A
authors.initials: MA
authors.lastname: van Baak
authors.forename: Marco
authors.initials: M
authors.lastname: Mensink
authors.forename: Wim H M
authors.initials: WH
authors.lastname: Saris
authors.forename: Ellen E
authors.initials: EE
authors.lastname: Blaak
mesh_terms: D000328:Adult; D000886:Anthropometry; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008875:Middle Aged; D018657:Muscle Fibers, Slow-Twitch / Q000378:metabolism*; D018482:Muscle, Skeletal / Q000378:metabolism*; D002787:Sterol Esterase / Q000235:genetics / Q000378:metabolism*
chemical_list: D002787:Sterol Esterase