DLK1(PREF1) is a negative regulator of adipogenesis in CD105⁺/CD90⁺/CD34⁺/CD31⁻/FABP4⁻ adipose-derived stromal cells from subcutaneous abdominal fat pats of adult women.
The main physiological function of adipose-derived stromal/progenitor cells (ASC) is to differentiate into adipocytes. ASC are most likely localized at perivascular sites in adipose tissues and retain the capacity to differentiate into multiple cell types. Although cell surface markers for ASC have been described, there is no complete consensus on the antigen expression pattern that will precisely define these cells. DLK1(PREF1) is an established marker for mouse adipocyte progenitors which inhibits adipogenesis. This suggests that DLK1(PREF1) could be a useful marker to characterize human ASC. The DLK1(PREF1) status of human ASC is however unknown. In the present study we isolated ASC from the heterogeneous stromal vascular fraction of subcutaneous abdominal fat pats of adult women. These cells were selected by their plastic adherence and expanded to passage 5. The ASC were characterized as relatively homogenous cell population with the capacity to differentiate in vitro into adipocytes, chondrocytes, and osteoblasts and the immunophenotype CD105⁺/CD90⁺/CD34⁺/CD31⁻/FABP4⁻. The ASC were positive for DLK1(PREF1) which was well expressed in proliferating and density arrested cells but downregulated in the course of adipogenic differentiation. To investigate whether DLK1(PREF1) plays a role in the regulation of adipogenesis in these cells RNAi-mediated knockdown experiments were conducted. Knockdown of DLK1(PREF1) in differentiating ASC resulted in a significant increase of the expression of the adipogenic key regulator PPARγ2 and of the terminal adipogenic differentiation marker FABP4. We conclude that DLK1(PREF1) is well expressed in human ASC and acts as a negative regulator of adipogenesis. Moreover, DLK1(PREF1) could be a functional marker contributing to the characterization of human ASC.
Department of Cell Metabolism and Differentiation Research, Institute for Biomedical Aging Research of the Austrian Academy of Sciences, Rennweg 10, A-6020 Innsbruck, Austria.
Maria C
MC
Mitterberger
Stefan
S
Lechner
Monika
M
Mattesich
Andreas
A
Kaiser
Daniela
D
Probst
Nikolaus
N
Wenger
Gerhard
G
Pierer
Werner
W
Zwerschke
D050156:Adipogenesis; D000328:Adult; D015703:Antigens, CD; D018952:Antigens, CD34; D002135:Calcium-Binding Proteins; D002478:Cells, Cultured; D015536:Down-Regulation; D000071063:Endoglin; D050556:Fatty Acid-Binding Proteins; D005260:Female; D055785:Gene Knockdown Techniques; D006801:Humans; D036341:Intercellular Signaling Peptides and Proteins / Q000235:genetics* / Q000378:metabolism*; D008565:Membrane Proteins / Q000235:genetics* / Q000378:metabolism*; D008875:Middle Aged; D019408:Platelet Endothelial Cell Adhesion Molecule-1; D011506:Proteins / Q000378:metabolism*; D011956:Receptors, Cell Surface; D017154:Stromal Cells / Q000166:cytology*; D050507:Subcutaneous Fat, Abdominal / Q000166:cytology*; D018800:Thy-1 Antigens
D015703:Antigens, CD; D018952:Antigens, CD34; D002135:Calcium-Binding Proteins; C512941:DLK1 protein, human; C064206:ENG protein, human; D000071063:Endoglin; C493410:FABP4 protein, human; D050556:Fatty Acid-Binding Proteins; D036341:Intercellular Signaling Peptides and Proteins; D008565:Membrane Proteins; D019408:Platelet Endothelial Cell Adhesion Molecule-1; D011506:Proteins; D011956:Receptors, Cell Surface; D018800:Thy-1 Antigens