促酰化蛋白诱导3T3-F442A前脂肪细胞分化的机制

A New Adipocytes Derived Protein,Acylation Stimulating Protein Inducing 3T3-F442A Preadipocytes to Differentiate

目的初步探讨促酰化蛋白诱导前脂肪细胞分化的作用及其可能机制。方法以3T3-F442A前脂肪细胞为研究对象,分为促酰化蛋白组(促酰化蛋白诱导分化)和对照组(无诱导分化剂)。在不同的分化时间点比较两组细胞的形态学变化和分化率;采用3H-油酸掺入法测定脂肪细胞甘油三酯合成率,化学比色法测定细胞中甘油三酯的总量。在诱导分化第0、1、2、4和6天收获细胞,采用逆转录聚合酶链反应检测转录因子过氧化体增殖物激活型受体γ、C/EBPδ和C/EBPαmRNA表达情况。结果促酰化蛋白可诱导3T3-F442A前脂肪细胞向成熟脂肪细胞的形态转变,且分化率较高,与对照组相比差异有显著性(P<0.05)。促酰化蛋白促进3T3-F442A前脂肪细胞的甘油三酯合成,并增加细胞甘油三酯的总量,均明显高于对照组(P<0.05)。转录因子C/EBPδ、C/EBPα和过氧化体增殖物激活型受体γmRNA的表达呈现一定的时间顺序,其中C/EBPδmRNA在3T3-F442A前脂肪细胞分化早期中表达水平急剧升高,然后又迅速下降至很低;而C/EBPαmRNA和过氧化体增殖物激活型受体γmRNA的表达随着分化的进行而逐渐升高,且在分化晚期始终保持高水平的表达。结论新型脂源性激素促酰化蛋白具有诱导前脂肪细胞分化的生物学作用,转录因子C/EBPδ、C/EBPα和过氧化体增殖物激活型受体γmRNA的时序性表达,可能是促酰化蛋白诱导3T3-F442A前脂肪细胞分化的重要分子机制之一。

Aim To study the role of acylation stimulating protein for the differentiation of 3T3-F442A preadipocytes and explore the molecular mechanism of it. Methods There were two groups in this study： acylation stimulating protein （AsP） group （induced to differentiate by AsP） and control group（ without inducers）. The morphological changes were observed by Oil- Red O staining. Tfiglyceride （TG） synthesis and TG mass were assayed by chemical colorimetry. The cell were harvested on the 0th day,1th day, 2th, 4th day, 6th day after induced differentiation and total RNAofthese cell were abstracted. The transcription factor peroxisome prolifemtor activated receptor γ（ PPARγ）, C/EBPα, C/EBPδ mRNAs expression were assayed by reverse transcription-polymerase chain reaction（RT-PCR）. Results 3T3-F442A preadipoeytes were induced to differentiate with AsP alone. Fat droplets were clearly visible in the cytoplasm of 3T3-F442A cell. The differentiation rate were high （80%） in AsP group. In AsP group TG synthesis and TG mass were significantly increased, both of them were higher than that of control group （ P 〈 0.05）. PPARγ mRNA expression in the 3T3- F442A cell were low on 0th day of induced differentiation, and it was increase significantly on the 1th and 2th day induced by AsP（ P 〈 0.05}. It continued to increase significantly on the 4th and 6th day（ P 〈 0.05）. The C/EBPδ mRNA were expressed in low level on 0th day of differentiation induced by ASp and the expression level was increase significantly on the 1th and 2th day of differentiation（ P 〈 0.05）. But the expression of C/EBPδ mRNA was decreased on the 4th and 6th day, there were no significant difference compared with that of 0th day （ P 〉 0.05）. .The expression of C/EBPα mRNA was very low on the 0th day of differentiation induced by AsP. It was increased on the 1th and 2th