REGULATION OF PLATELET-DERIVED GROWTH-FACTOR SECRETION AND GENE-EXPRESSION IN HUMAN LIVER FAT-STORING CELLS
REGULATION OF PLATELET-DERIVED GROWTH-FACTOR SECRETION AND GENE-EXPRESSION IN HUMAN LIVER FAT-STORING CELLS
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DOI：
10.1016/0016-5085(94)90236-4
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发表时间：
1994-10-01
期刊：
影响因子：
29.4
通讯作者：
ABBOUD, HE
中科院分区：
文献类型：
--
作者：
MARRA, F;CHOUDHURY, GG;ABBOUD, HE
背景/目的：肝脏脂肪储存细胞（FSCs）在肝损伤过程中积极增殖并分泌细胞外基质。血小板衍生生长因子（PDGF）是培养的FSCs的有效丝裂原。在本研究中，我们研究了PDGF基因在培养的人肝FSCs中的表达和产生的调控。方法：采用Northern blotting法和核糖核酸酶保护法分别检测PDGF a链和b链的表达。通过条件培养基的免疫沉淀和免疫印迹以及FSC的代谢标记和免疫沉淀来评估PDGF的分泌。结果：检测到3个PDGF a链转录本。肉豆蔻酸酯佛波酯（10(-7)mol/L）或PDGF BB （20 ng/mL）刺激FSC可增加PDGF a链和b链信使RNA的稳态水平。PDGF AA对a链信使RNA水平有小的刺激作用，但对b链信使RNA水平无刺激作用。FSCs在条件培养基中分泌PDGF。分泌的蛋白具有生物活性，因为浓缩的条件培养基诱导胸腺嘧啶掺入增加，而抗pdgf抗体抑制了胸腺嘧啶掺入。结论：本研究表明培养的FSCs表达PDGF A链和b链基因，并在培养基中释放具有生物活性的PDGF。这些数据提出了PDGF在FSCs中发挥自分泌或短环旁分泌作用的可能性，这可能是肝损伤期间维持增殖状态的一种机制。
Background/Aims: Liver fat-storing cells (FSCs) actively proliferate and secrete extracellular matrix during liver injury. Platelet-derived growth factor (PDGF) is a potent mitogen for cultured FSCs. In the present study, we investigated the regulation of PDGF gene expression and production in cultured human liver FSCs. Methods: PDGF A-chain and B-chain expression was analyzed by Northern blotting and ribonuclease protection assay, respectively. Secretion of PDGF was evaluated by immunoprecipitation and immunoblotting of conditioned medium and metabolic labeling of FSC followed by immunoprecipitation. Results: Three PDGF A-chain transcripts were detectable. Stimulation of FSC with phorbol myristate acetate (10(-7) mol/L) or PDGF BB (20 ng/mL) increased steady-state levels of PDGF A-chain and B-chain messenger RNA. PDGF AA had a small stimulatory effect on A-chain but not B-chain messenger RNA levels. FSCs secrete PDGF in the conditioned medium. The secreted protein is bioactive, because concentrated conditioned medium induced an increase in thymidine incorporation that was inhibited by anti-PDGF antibodies. Conclusions: This study shows that cultured FSCs express PDGF A- and B-chain genes and release bioactive PDGF in the culture medium. These data raise the possibility of an autocrine or short-loop paracrine effect of PDGF in FSCs as a mechanism contributing to the maintenance of the proliferative state during liver injury.