Human adipose triglyceride lipase (PNPLA2) is not regulated by obesity and exhibits low in vitro triglyceride hydrolase activity
- A. MairalAffiliated withInserm, U586, Obesity Research UnitPaul Sabatier University, Louis Bugnard Institute IFR31
- , D. LanginAffiliated withInserm, U586, Obesity Research UnitPaul Sabatier University, Louis Bugnard Institute IFR31Toulouse University Hospital
- , P. ArnerAffiliated withDepartment of Medicine, Karolinska Institutet, Karolinska University Hospital Huddinge
- , J. HoffstedtAffiliated withDepartment of Medicine, Karolinska Institutet, Karolinska University Hospital Huddinge Email author
The recent identification of murine adipose triglyceride lipase (ATGL, now known as patatin-like phospholipase domain containing 2 [PNPLA2]), gene product of Pnpla2, has questioned the unique role of hormone sensitive lipase (HSL, now known as LIPE), gene product of Lipe, in fat cell lipolysis. Here, we investigated human ATGL and HSL adipose tissue gene expression and in vitro lipase activity.
Subjects, materials and methods
Levels of mRNA in adipose tissue from healthy obese and non-obese subjects were measured and lipase activity and adipocyte lipolytic capacity determined. HSL and ATGL cDNAs were transfected into Cos-7 cells and the relative tri- and diglyceride hydrolase activities were measured.
Obesity was associated with a decreased subcutaneous and increased omental adipose tissue level of HSL mRNA. Subcutaneous HSL mRNA content was normalised upon weight reduction. In contrast, ATGL mRNA levels were unaffected by obesity and weight reduction. A high adipose tissue lipase activity was associated with increased maximal lipolysis and increased HSL, but not with ATGL mRNA levels. The in vitro triglyceride hydrolase activity of HSL was markedly higher than that of ATGL and contrary to HSL, ATGL was devoid of diglyceride hydrolase activity. The use of a selective HSL-inhibitor resulted in complete inhibition of HSL-mediated tri- and diglyceride hydrolase activity. The pH profile of human white adipose tissue triolein hydrolase activity was identical to that of HSL but differed from the ATGL profile.
HSL, but not ATGL gene expression shows a regulation according to obesity status and is associated with increased adipose tissue lipase activity. Moreover, HSL has a higher capacity than ATGL to hydrolyse triglycerides in vitro.
KeywordsAdipocyte ATGL Catecholamines Cos-7 cell HSL LIPE Lipolysis PNPLA2
- Human adipose triglyceride lipase (PNPLA2) is not regulated by obesity and exhibits low in vitro triglyceride hydrolase activity
Volume 49, Issue 7 , pp 1629-1636
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- 1. Inserm, U586, Obesity Research Unit, Toulouse, France
- 2. Paul Sabatier University, Louis Bugnard Institute IFR31, Toulouse, France
- 3. Toulouse University Hospital, Toulouse, France
- 4. Department of Medicine, Karolinska Institutet, Karolinska University Hospital Huddinge, 14186, Stockholm, Sweden