Sandorfi N, Louneva N, Hitraya E, Hajnoczky G, Saitta B, Jimenez S A
Division of Rheumatology, Department of medicine, Thomas Jefferson University, Philadelphia, PA 19107-5041, USA.
Ann Rheum Dis. 2005 Dec;64(12):1685-91. doi: 10.1136/ard.2005.037515. Epub 2005 May 18.
The anti-tumour antibiotic mithramycin is also a potent inhibitor of fibrosis after glaucoma surgery. This drug displays high affinity binding to GC-rich sequences in DNA, including those present in the promoter of the gene encoding the alpha1 chain of type I collagen (COL1A1).
To evaluate the effects of mithramycin on COL1A1 expression in systemic sclerosis fibroblasts.
Confluent cultures of dermal fibroblasts from patients with recent onset diffuse systemic sclerosis were treated with mithramycin in vitro. Cell viability and protein expression were examined by fluorescence and confocal imaging. Type I collagen production was analysed by confocal imaging and metabolic labelling. COL1A1 messenger RNA levels and stability were assessed by northern hybridisation, and COL1A1 transcription was examined by transient transfections.
Treatment of systemic sclerosis fibroblasts with mithramycin (10-100 nmol/l) did not cause significant cytotoxicity. Type I collagen biosynthesis decreased by 33-40% and 50-70% in cells cultured with mithramycin at 10 nmol/l and 100 nmol/l, respectively. Mithramycin at 50 nmol/l decreased COL1A1 mRNA levels by 40-60%. The effects of mithramycin on collagen gene expression were mediated by transcriptional and post-transcriptional mechanisms as shown by the reduction of COL1A1 promoter activity and by a decrease in the stability of these transcripts, respectively.
Mithramycin causes potent inhibition of collagen production and gene expression in systemic sclerosis dermal fibroblasts in vitro in the absence of cytotoxic effects. These results suggest that this drug may be an effective treatment for the fibrotic process which is the hallmark of systemic sclerosis.
抗肿瘤抗生素光辉霉素也是青光眼手术后纤维化的有效抑制剂。该药物与DNA中富含鸟嘌呤-胞嘧啶的序列具有高亲和力结合，包括存在于编码I型胶原α1链（COL1A1）基因启动子中的序列。
评估光辉霉素对系统性硬化症成纤维细胞中COL1A1表达的影响。
用光辉霉素体外处理近期发病的弥漫性系统性硬化症患者的真皮成纤维细胞汇合培养物。通过荧光和共聚焦成像检查细胞活力和蛋白质表达。通过共聚焦成像和代谢标记分析I型胶原的产生。通过Northern杂交评估COL1A1信使核糖核酸水平和稳定性，并通过瞬时转染检查COL1A1转录。
用光辉霉素（10 - 100 nmol/L）处理系统性硬化症成纤维细胞不会引起明显的细胞毒性。在分别用10 nmol/L和100 nmol/L光辉霉素培养的细胞中，I型胶原生物合成分别减少33% - 40%和50% - 70%。50 nmol/L的光辉霉素使COL1A1 mRNA水平降低40% - 60%。光辉霉素对胶原基因表达的影响分别通过COL1A1启动子活性的降低和这些转录本稳定性的降低所显示的转录和转录后机制介导。
在无细胞毒性作用的情况下，光辉霉素在体外可有效抑制系统性硬化症真皮成纤维细胞中的胶原产生和基因表达。这些结果表明，该药物可能是治疗作为系统性硬化症标志的纤维化过程的有效疗法。
