Stankov Metodi V, Schmidt Reinhold E, Behrens Georg M N
Clinic for Immunology and Rheumatology, Hannover Medical School, Carl-Neuberg-Strasse 1, 30625 Hannover, Germany.
Exp Biol Med (Maywood). 2009 Dec;234(12):1484-92. doi: 10.3181/0907-RM-205.
Current understanding of adipogenesis derives mainly from studies with in vitro cell culture systems with divergent experimental requirements. We aimed to investigate the discrepancy between the anti-adipogenic effects of the HIV protease-inhibitor indinavir (IDV) in vitro and the lack of evidence that IDV inhibits adipogenesis in humans.
We studied cell viability and adipogenesis in murine 3T3-F442A, 3T3-L1 and primary human subcutaneous preadipocytes (phsPA). Differentiation was studied after activation of the established four signalling pathways in different combinations. We analyzed CCAAT/enhancer-binding protein (C/EBP) alpha and peroxisome proliferator-activated receptor (PPAR) gamma expression and triacylglyceride accumulation. Cells were exposed to IDV at concentrations around therapeutic C(max) levels and higher (10 muM and 20 muM) for up to 30 days.
Under insulin and fetal calf serum (FCS) input, IDV inhibited 3T3-F442A differentiation, an effect that was partially rescued by the addition of 3-isobutyl-1-methylxanthine (IBMX) stimulation. Combined stimulation with FCS, insulin, dexamethasone (DEX) and IBMX led to normal 3T3-L1 differentiation even in the presence of IDV. However, omission of IBMX rendered this cell line sensitive to IDV's anti-adipogenic effects. Differentiation of phsPA requiring complete adipogenic stimulation was not affected by IDV presence.
Our data suggest that the potency of IDV to impair differentiation under partial stimulation disappears when all of the differentiation pathways are activated. Such compensatory mechanisms might be responsible for the inability of the drug to affect adipogenesis in vivo.
目前对脂肪生成的理解主要源于对具有不同实验要求的体外细胞培养系统的研究。我们旨在研究HIV蛋白酶抑制剂茚地那韦（IDV）在体外的抗脂肪生成作用与缺乏IDV抑制人体脂肪生成证据之间的差异。
我们研究了小鼠3T3-F442A、3T3-L1和原代人皮下前脂肪细胞（phsPA）的细胞活力和脂肪生成。在以不同组合激活已确立的四种信号通路后研究分化情况。我们分析了CCAAT/增强子结合蛋白（C/EBP）α和过氧化物酶体增殖物激活受体（PPAR）γ的表达以及三酰甘油的积累。细胞暴露于浓度约为治疗性C（max）水平及更高（10μM和20μM）的IDV中长达30天。
在胰岛素和胎牛血清（FCS）输入下，IDV抑制3T3-F442A分化，添加3-异丁基-1-甲基黄嘌呤（IBMX）刺激可部分挽救该效应。FCS、胰岛素、地塞米松（DEX）和IBMX联合刺激即使在存在IDV的情况下也能使3T3-L1正常分化。然而，省略IBMX会使该细胞系对IDV的抗脂肪生成作用敏感。需要完全脂肪生成刺激的phsPA分化不受IDV存在的影响。
我们的数据表明，当所有分化途径都被激活时，IDV在部分刺激下损害分化的能力消失。这种补偿机制可能是该药物无法在体内影响脂肪生成的原因。
