A New Preadipocyte Cell Line, AP-18, Established from Adult Mouse Adipose Tissue

A New Preadipocyte Cell Line, AP-18, Established from Adult Mouse Adipose Tissue

HIDEYUKI DOI, NAKUI MASAKI, HITOSHI TAKAHASHI, HIROMICHI KOMATSU, KEISEI FUJIMORI and SUSUMU SATOMI

Division of Advanced Surgical Science and Technology, Graduate School of Medicine Tohoku University, Sendai, Japan

Establishing preadipocyte cell lines from mature adipose tissues could help lead to a better understanding of adipogenesis. We have established a unique preadipocyte cell line, AP-18, derived from the subepidermal layer of ear skin from an adult C3H/HeM mouse. AP-18 cells exhibit fibroblast-like morphology, slow growth, and contact inhibition. The doubling time of AP-18 cells is 50-60 h, which is about 2-fold longer than that of well-known 3T3-L1 cells derived from mouse embryos. A small population of AP-18 cells spontaneously differentiates into adipocytes by 8 days after confluence, as judged by the accumulation of triglyceride droplets. Treatment of confluent AP-18 preadipocytes with adipogenic agents, containing dexamethasone, 3-methyl-1-isobutylxanthine, and insulin, increased triglyceride contents about 5-fold compared to the contents in untreated cells. We also analyzed mRNA expression profiles for key transcription factors involved in adipocyte differentiation, peroxisome proliferator-activated receptor (PPAR)γ and the CCAAT/enhancer binding protein (C/EBP) family, and for differentiation markers, aP2, adipocyte-specific fatty acid-binding protein and adipsin, adipocyte-specific serine protease. AP-18 preadipocytes express mRNAs for C/EBPβ, C/EBPα, PPARγ, and aP2 before differentiation, but not adipsin mRNA. Expression of aP2 mRNA was increased in fully differentiated AP-18 cells. Likewise, expression of adipsin mRNA was increased after induced differentiation of AP-18 cells and reached the highest level in fully differentiated adipocytes. Thus, differentiation of AP-18 cells is associated with the increased expression of aP2 and adipsin mRNAs. The newly established AP-18 cell line provides a useful model for investigating adipocyte differentiation and adipogenesis.

keywords ——preadipocyte; mouse; proliferation; differentiation; adipogenesis

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Tohoku J. Exp. Med., 2005, 207, 209-216

Correspondence: Hideyuki Doi, M.D., Division of Advanced Surgical Science and Technology, Graduate School of Medicine, Tohoku University, Seiryomachi, Aoba-ku, Sendai 980-8574, Japan.

e-mail: dovaline@mail.tains.tohoku.ac.jp