Falanga V, Takagi H, Ceballos P I, Pardes J B
University of Miami School of Medicine, Department of Dermatology and Cutaneous Surgery, Florida 33136.
Exp Cell Res. 1994 Jul;213(1):80-4. doi: 10.1006/excr.1994.1175.
We have investigated receptor binding of epidermal growth factor (EGF) and transforming growth factor-beta 1 (TGF-beta) in cultures of human dermal fibroblasts exposed to low (2%, hypoxia) or standard (20%) oxygen tension. Compared to standard oxygen, the binding of both 125I-TGF-beta and 125I-EGF in low oxygen tension was diminished by a mean of 65 and 62%, respectively (P < 0.02), and was reversed by reexposure of cultures to standard oxygen tension. Low oxygen tension decreased the number of binding sites of both EGF (mean = 44%) and TGF-beta (mean = 33%). Preincubation of the media in the two different oxygen conditions showed that alterations in the redox potential of the medium was not responsible for the changes observed in receptor binding. As shown by Northern analysis, diminished TGF-beta receptor binding in hypoxia was accompanied by up to a 10-fold decrease in mRNA levels of TGF-beta type II receptor. We conclude that low oxygen tension decreases EGF and TGF-beta receptor binding and synthesis.
我们研究了暴露于低氧（2%，缺氧）或标准氧（20%）张力下的人皮肤成纤维细胞培养物中表皮生长因子（EGF）和转化生长因子-β1（TGF-β）的受体结合情况。与标准氧相比，低氧张力下125I-TGF-β和125I-EGF的结合分别平均减少了65%和62%（P < 0.02），并且当培养物重新暴露于标准氧张力时这种减少得以逆转。低氧张力降低了EGF（平均 = 44%）和TGF-β（平均 = 33%）的结合位点数。在两种不同氧条件下对培养基进行预孵育表明，培养基氧化还原电位的改变并非受体结合所观察到变化的原因。如Northern分析所示，缺氧时TGF-β受体结合减少伴随着TGF-β II型受体mRNA水平最多10倍的下降。我们得出结论，低氧张力会降低EGF和TGF-β的受体结合及合成。
