MECHANISM OF BLEOMYCIN INDUCED COLLAGEN SYNTHESIS

博莱霉素会导致肺纤维化。从中国分离的多聚体 博莱霉素处理的成纤维细胞合成增加的前胶原 控制多聚体，而非胶原蛋白的合成不受影响。 I型和多聚体合成的时间反应 博莱霉素处理的雏鸡肺中的III型前胶原 与博莱霉素处理雏鸡中这些前胶原的合成比较 肺成纤维细胞。细胞总前胶原I型mRNAs含量 不会因博莱霉素治疗而改变。然而，I型前胶原mRNAs 在多聚体中升高，在核和后多聚体中减少 细胞质。这些数据表明I型前胶原存在分割效应。 MRNAs。博莱霉素增加多聚体的分子机制(S) 将测定前胶原的合成。I型与TYPE的合成 III型前胶原mRNAs在总细胞、细胞核及其在细胞内的积聚 将测定后多聚体细胞质和多聚体。其效果 博莱霉素对前胶原hnRNA核内数量的影响 下定决心。将从对照和博莱霉素处理组分离细胞核 成纤维细胞并在体外转录。第一类和第三类的运输 将评估来自细胞核和多聚体的前胶原mRNAs。其影响 博莱霉素对细胞、胞浆和细胞核总降解的影响 将测定I型和III型前胶原mRNA序列。至 确定多聚体前胶原合成增加的机制(S)， 将分离多聚体mRNPs，并测定I型前胶原和 将确定III型mRNAs。I型和III型前胶原 由这些mRNPs在体外合成的将被检测。盐渍的洗涤 从对照和博莱霉素处理的成纤维细胞中分离出的多聚体将被 添加到含有对照的体外蛋白质合成系统中 用多聚体确定是否存在博莱霉素诱导的刺激 因素(S)。一种前胶原合成抑制因子的存在 将对对照多聚体进行评估。如果有这样一个因素(S)，我们 把这些分离出来。我们还将确定博莱霉素治疗是否会改变 前胶原的分泌、积累和/或降解。这个成纤维细胞 博莱霉素性肺毒性模型可用于筛选 博莱霉素及其类似物对成纤维细胞胶原的直接作用 新陈代谢。此外，这些研究还可能阐明分子基础。 博莱霉素性肺纤维化的治疗。

Bleomycin causes pulmonary fibrosis. Polysomes isolated from bleomycin-treated fibroblasts synthesize increased procollagen as compared to control polysomes, while noncollagen protein synthesis is not effected. The temporal response of cellular and polysomal synthesis of type I and type III procollagens in the lungs of bleomycin-treated chicks will be compared to the synthesis of these procollagens in bleomycin-treated chick lung fibroblasts. The contents of total cellular procollagen type I mRNAs are not altered by bleomycin treatment. However, type I procollagen mRNAs are elevated in polysomes and decreased in nuclei and in the post-polysomal cytoplasm. These data indicate a partitioning effect on type I procollagen mRNAs. The molecular mechanism(s) by which bleomycin increases polysomal procollagen synthesis will be determined. The synthesis of type I and type III procollagen mRNAs in the total cell, nuclei and their accumulation into the post-polysomal cytoplasm and polysomes will be determined. The effect of bleomycin on the nuclear quantities of procollagen hnRNAs will also be determined. Nuclei will be isolated from control and bleomycin-treated fibroblasts and transcribed in vitro. The transport of type I and type III procollagen mRNAs from nuclei and polysomes will be assessed. The effects of bleomycin on the degradation of total cellular, cytoplasmic and nuclear type I and type III procollagen mRNA sequences will be determined. To identify the mechanism(s) of increased polysomal procollagen synthesis, polysomal mRNPs will be isolated and the contents of procollagen type I and type III mRNAs will be determined. Procollagen type I and type III synthesized by these mRNPs in vitro will be determined. The salt wash of polysomes isolated from control and bleomycin-treated fibroblasts will be added to an in vitro protein synthesizing system containing control polysomes to determine the presence of a bleomycin-induced stimulating factor(s). The presence of a procollagen synthesis inhibiting factor in the control polysomes will be assessed. If such a factor(s) exists we isolate these. We will also determine if bleomycin treatment alters the secretion, accumulation and/or degradation of procollagen. This fibroblast model of bleomycin-induced lung toxicity may be then used to screen the direct effect of bleomycin and its analogues on fibroblast collagen metabolism. In addition, these studies may elucidate the molecular basis of bleomycin-induced pulmonary fibrosis.