Adipose tissue expression of gelatinases in mouse models of obesity.
Following the observation by Brown et al. (Am J Physiol 1997; 272: C937-49) that primary rat adipocytes in culture secrete gelatinase A (MMP-2), we have evaluated gelatinase expression in adipose tissue with the use of mouse models of obesity. Wild-type mice were kept on a standard fat diet (SFD) or on a high fat diet (42% fat, HFD) and- genetically obese db/db mice were kept on SFD; gonadal and subcutaneous fat pads were removed and analysed ex vivo. These studies revealed that: 1) the HFD induced adipocyte hypertrophy; 2) after 32 weeks, significantly higher levels of 70 kDa (p <0.05) and 65 kDa proMMP-2 (p <0.01) were observed in extracts of gonadal fat pads of mice on HFD; 3) the contribution of active MMP-2 to the total level was comparable in SFD and HFD groups (20 to 30%); and 4) gelatinase B (MMP-9) was not consistently detected. These findings were confirmed by gelatin zymography and by mRNA determination using competitive RT-PCR. The presence of MMP-2 in the adipose tissue was confirmed immunologically and its localization in adipocytes revealed by immunogold electron microscopy. The potential functional role of MMP-2 in adipose tissue remains to be determined.
Lijnen
H R
HR
Center for Molecular and Vascular Biology, University of Leuven, Belgium. roger.lijnen@med.kuleuven.ac.be
Maquoi
E
E
Holvoet
P
P
Mertens
A
A
Lupu
F
F
Morange
P
P
Alessi
M C
MC
Juhan-Vague
I
I
D000273:Adipose Tissue / Q000201:enzymology* / Q000648:ultrastructure; D000818:Animals; D004041:Dietary Fats / Q000494:pharmacology; D004195:Disease Models, Animal; D004792:Enzyme Precursors / Q000032:analysis; D018093:Gelatinases / Q000032:analysis* / Q000235:genetics; D006651:Histocytochemistry; D006984:Hypertrophy; D020778:Matrix Metalloproteinase 2 / Q000032:analysis / Q000235:genetics; D020780:Matrix Metalloproteinase 9 / Q000032:analysis; D051379:Mice; D008820:Mice, Obese; D008854:Microscopy, Electron; D009765:Obesity / Q000201:enzymology / Q000473:pathology*; D012333:RNA, Messenger / Q000032:analysis
D004041:Dietary Fats; D004792:Enzyme Precursors; D012333:RNA, Messenger; D018093:Gelatinases; D020778:Matrix Metalloproteinase 2; D020780:Matrix Metalloproteinase 9