Hypoxic conditions stimulate the production of angiogenin and vascular endothelial growth factor by human renal proximal tubular epithelial cells in culture
Hypoxic conditions stimulate the production of angiogenin and vascular endothelial growth factor by human renal proximal tubular epithelial cells in culture
复制标题
DOI：
10.1093/ndt/gfl041
复制
发表时间：
2006-06-01
影响因子：
6.1
通讯作者：
Okumura, Ken
中科院分区：
文献类型：
--
作者：
Nakamura, Masayuki;Yamabe, Hideaki;Okumura, Ken
肾小管间质区慢性低氧是肾功能退化和肾小管间质损害的重要原因。先前的报告表明，维持肾血流在抑制进行性肾损害中起作用。新生血管对于维持血流是重要的。我们研究了生产的血管生成因子培养肾近端肾小管上皮细胞（PTEC）在缺氧conditions.Methods。培养的PTEC暴露于正常和低氧条件。酶联免疫吸附法检测细胞培养上清中血管生成素（ANG）和血管内皮生长因子（VEGF）的含量。采用实时荧光定量RT-PCR检测血管生成素（ANG）和血管内皮生长因子（VEGF）mRNA在PTEC中的表达。应用免疫荧光技术检测血管生成素（ANG）、血管内皮生长因子（VEGF）和缺氧诱导因子-1（HIF-1）的表达。结果：PTEC细胞培养上清中存在ANG和VEGF，PTEC细胞中存在ANG和VEGF mRNA。低氧刺激PTEC分泌ANG（2.5倍低氧，P<0.001）和VEGF（3.2倍低氧，P<0.001）。缺氧6 h时ANG mRNA表达增加1.38倍（P<0.05），缺氧24 h时VEGF mRNA表达增加2.04倍（P<0.01）。低氧条件下PTEC中ANG、VEGF和HIF-1蛋白表达增强。结论：缺氧条件下，PTEC分泌的ANG和VEGF可能通过增加HIF-1的表达而调节肾血管新生和血管重建。
Background.Chronic low oxygen in the tubulointerstitial area is a crucial cause of renal degradation and tubulointerstitial damage. Previous reports have suggested that the maintenance of renal blood flow plays a role in the suppression of progressive renal damage. Neovascularization is important for the maintenance of blood flow. We studied the production of angiogenic factors by culturing renal proximal tubular epithelial cells (PTEC) under hypoxic conditions.Methods.Cultured PTEC were exposed to normal and low-oxygen conditions. The levels of angiogenin (ANG) and vascular endothelial growth factor (VEGF) in the cell supernatants were measured by enzyme-linked immunosorbent assay. The messenger RNAs (mRNAs) of ANG and VEGF in the PTEC were examined by real-time reverse transcriptase polymerase chain reaction (real-time RT–PCR). The presence of ANG, VEGF and hypoxia-inducible factor-1 (HIF-1) was studied by immunofluorescence techniques. The effect of cobalt chloride (CoCl2), which is an HIF-1 inducer, on the production of ANG and VEGF was also examined in order to elucidate the contribution of the HIF-1 pathway to the production of these cytokines.Results.ANG and VEGF were demonstrated to exist in the cell supernatants, and ANG and VEGF mRNAs were detected in the PTEC. Hypoxic conditions stimulated the secretion of ANG (2.5-foldvsnormoxia,P<0.001) and VEGF (3.2-foldvsnormoxia,P<0.001) by PTEC. Hypoxic conditions increased the mRNA expression of ANG for 6 h (1.38-foldvsnormoxia,P<0.05) and VEGF for 24 h (2.04-foldvsnormoxia,P<0.01). Hypoxic conditions also enhanced ANG, VEGF and HIF-1 protein expression in PTEC. The CoCl2increased the secretion of ANG (5.2-foldvscontrol,P<0.0001) and VEGF (2.3-foldvscontrol,P<0.0001) by PTEC.Conclusion.Under hypoxic conditions, the ANG and VEGF secreted by PTEC may modulate angiogenesis and vascular remodeling in the renal interstitium via an increase in the production of HIF-1.