Elastin synthesis by ligamentum nuchae fibroblasts: effects of culture conditions and extracellular matrix on elastin production.
Elastin synthesis by ligamentum nuchae fibroblasts: effects of culture conditions and extracellular matrix on elastin production.
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DOI：
10.1083/jcb.90.2.332
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发表时间：
1981-08
期刊：
影响因子：
--
通讯作者：
Starcher B
中科院分区：
文献类型：
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作者：
Mecham RP;Lange G;Madaras J;Starcher B
维持培养的胎牛颈韧带成纤维细胞能合成可溶性弹性蛋白，但不能形成不溶性弹性纤维。分泌的弹性蛋白前体在培养基中积累，并使用弹性蛋白放射免疫测定法进行测量。当研究不同胎龄的胎犊韧带组织中弹性蛋白的生成时，从发育最后三个月的胎犊组织中提取的细胞产生的弹性蛋白明显多于从较年轻的胎犊组织中提取的细胞，弹性蛋白的最大合成发生在出生前不久。在低密度韧带细胞中检测到可溶性弹性蛋白，直到增殖开始受到密度抑制，细胞进入静止状态。每个细胞的可溶性弹性蛋白产量也随着群体的增加和培养年龄的增加而下降。在含有5%胎牛血清的培养基中培养的细胞产生的可溶性弹性蛋白大约是在无血清培养基中培养的细胞的四倍。地塞米松（0.1微克/毫升）和博来霉素（1微克/毫升）分别使培养细胞的可溶性弹性蛋白产量增加180%和50%，而茶碱（5微克/毫升）使产量降低50%，并拮抗地塞米松的刺激。抗坏血酸（50微克/毫升），大豆胰蛋白酶抑制剂（1毫克/毫升），胰岛素（100微克/毫升）和氨基乙腈（50微克/毫升）没有影响，但环己亚胺在10(-4)M时完全抑制可溶性弹性蛋白的产生。与培养细胞相比，韧带组织碎（韧带细胞被体内细胞外基质包围）有效地将可溶性弹性蛋白前体融入不溶性交联弹性蛋白中。此外，组织肉糜中每个细胞（每微克DNA）的可溶性弹性蛋白产量高于维持在塑料上的细胞的弹性蛋白产量。这些结果表明，细胞外基质在韧带成纤维细胞弹性纤维的形成和稳定弹性蛋白表型表达中的作用。牛颈韧带成纤维细胞是体外研究弹性蛋白生物合成的良好模型。
Fetal bovine ligamentum nuchae fibroblasts maintained in culture synthesized soluble elastin but were unable to form the insoluble elastic fiber. Secreted elastin precursors accumulated in culture medium and were measured using a radioimmunoassay for elastin. When elastin production was examined in ligament tissue from fetal calves of various gestational ages, cells from tissue taken during the last trimester of development produced significantly more elastin than did cells from younger fetal tissue, with maximal elastin synthesis occurring shortly before birth. Soluble elastin was detected in ligament cells plated at low density until proliferation began to be density inhibited and the cells became quiescent. Also, soluble elastin production per cell declined with increasing population doubling or with age in culture. Cells grown in the presence of 5% fetal calf serum produced approximately four times as much soluble elastin as cells grown in serum-free medium. The addition of dexamethasone (0.1 microM) and bleomycin (1 microgram/ml) increased soluble elastin production by cultured cells 180% and 50%, respectively, whereas theophylline (5 micrograms/ml) depressed production 50% and antagonized stimulation by dexamethasone. Ascorbate (50 micrograms/ml), soybean trypsin inhibitor (1 mg/ml), insulin (100 microunits/ml), and aminoacetonitrile (50 micrograms/ml) had no effect, but cycloheximide at 10(-4) M completely inhibited soluble elastin production. In contrast to cells in culture, ligament tissue minces (ligament cells surrounded by in vivo extracellular matrix) efficiently incorporated soluble elastin precursors into insoluble, cross-linked elastin. In addition, soluble elastin production per cell (per microgram of DNA) was higher in tissue minces than elastin production by cells maintained on plastic. These results suggest a role for extracellular matrix in formation of the elastic fiber and in stabilizing elastin phenotypic expression by ligament fibroblasts. Fibroblasts from the bovine ligamentum nuchae present an excellent model for in vitro studies of elastin biosynthesis.