Falanga V, Qian S W, Danielpour D, Katz M H, Roberts A B, Sporn M B
University of Miami School of Medicine, Department of Dermatology and Cutaneous Surgery, Florida, 33101.
J Invest Dermatol. 1991 Oct;97(4):634-7. doi: 10.1111/1523-1747.ep12483126.
In this report, we have investigated the secretion and synthesis of transforming growth factor-beta 1 (TGF-beta 1) by human dermal fibroblast cultures in response to hypoxia (2% oxygen), and have compared it to standard oxygen culture conditions (15% oxygen at the cell surface). Sandwich enzyme-linked immunosorbent assay (SELISA) showed a selective and progressive increase in secretion of the TGF-beta 1 isoform in response to hypoxia, up to ninefold after cultures were exposed to low oxygen for 72 h; TGF-beta 2 peptide levels were not increased. We then investigated the transcriptional regulation of the TGF-beta 1 gene in response to low and standard oxygen tensions. In the first 24-48 h, TGF-beta 1 mRNA levels decreased steadily in both oxygen environments. This mRNA decline continued for up to 72 h in standard oxygen but not in cultures exposed to low oxygen tension. At 72 h, steady-state TGF-beta 1 mRNA levels were 8 times greater in low compared to standard oxygen, and this increase was reversible upon re-exposure of fibroblast cultures to standard oxygen tension for 24 h. Elevated TGF-beta 1 m-RNA levels in both low and standard oxygen declined steadily and with the same half-life after the addition of actinomycin D, suggesting that hypoxia increased TGF-beta 1 transcription rather than mRNA stability. We conclude that low oxygen tension upregulates the synthesis of TGF-beta 1 by human dermal fibroblasts, and leads to increased secretion of this peptide.
在本报告中，我们研究了人皮肤成纤维细胞培养物在缺氧（2%氧气）条件下转化生长因子-β1（TGF-β1）的分泌与合成，并将其与标准氧气培养条件（细胞表面15%氧气）进行了比较。夹心酶联免疫吸附测定（SELISA）显示，缺氧会导致TGF-β1亚型的分泌选择性地逐步增加，培养物暴露于低氧72小时后增加了9倍；TGF-β2肽水平未升高。然后，我们研究了低氧和标准氧张力下TGF-β1基因的转录调控。在最初的24至48小时内，两种氧气环境下TGF-β1 mRNA水平均稳步下降。在标准氧气环境中，这种mRNA下降持续长达72小时，但在暴露于低氧张力的培养物中则没有。在72小时时，低氧环境下的稳态TGF-β1 mRNA水平比标准氧气环境高8倍，并且当成纤维细胞培养物重新暴露于标准氧张力24小时后，这种增加是可逆的。添加放线菌素D后，低氧和标准氧气环境中升高的TGF-β1 mRNA水平均稳步下降且半衰期相同，这表明缺氧增加了TGF-β1的转录而非mRNA稳定性。我们得出结论，低氧张力上调了人皮肤成纤维细胞中TGF-β1的合成，并导致该肽分泌增加。
