High glucose induces cell hypertrophy and stimulates collagen gene transcription in proximal tubule.
High glucose induces cell hypertrophy and stimulates collagen gene transcription in proximal tubule.
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DOI：
10.1152/ajprenal.1990.259.4.f704
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发表时间：
1990-10
期刊：
影响因子：
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通讯作者：
F. N. Ziyadeh;Edward R. Snipes;Melanie Watanabe;R. Alvarez;S. Goldfarb;Thomas P. Haverty
中科院分区：
文献类型：
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作者：
F. N. Ziyadeh;Edward R. Snipes;Melanie Watanabe;R. Alvarez;S. Goldfarb;Thomas P. Haverty
糖尿病肾脏的肾小管间质改变与肾小球滤过率下降密切相关。在这项研究中，我们使用了小鼠近曲小管上皮细胞的细胞培养系统，以测试葡萄糖对细胞生长，大小和基质生物合成的影响。与生长在100 mg/dl葡萄糖中的细胞相比，生长在450 mg/dl葡萄糖中的细胞[3 H]胸苷掺入显著抑制。在较高葡萄糖浓度下生长的细胞稍大，它们的蛋白质含量和总蛋白质合成速率显著增加，并且它们分泌的IV型和I型前胶原大约是其两倍。相应地，稳态前胶原mRNA水平也增加：α 1（IV）前胶原增加2.6倍，α 2（I）前胶原增加2.2倍。此外，核径流研究表明，前胶原基因转录率刺激约50%，β-肌动蛋白转录率没有改变。我们使用氯霉素乙酰转移酶（CAT）报告基因构建体，以确定是否增加的α 2（I）基因的转录速率与其增强子序列的激活。当在高糖培养基中培养时，用增强子转染的细胞表现出CAT活性增加五倍以上。这些研究证明了高环境葡萄糖浓度对近端小管细胞生长和胶原蛋白生物合成的多种影响;尽管发生细胞肥大，但细胞增殖减少。前胶原基因转录速率受到刺激，这种反应有助于观察到的前胶原mRNA含量增加。增强子序列的激活可能是高葡萄糖水平增加I型前胶原转录的一种可能模式，推测涉及反式作用因子。
Tubulointerstitial changes in the diabetic kidney correlate closely with the decline in glomerular filtration. In this study, we used a cell culture system of mouse proximal tubule epithelial cells to test the effects of glucose on cell growth, size, and matrix biosynthesis. [3H]thymidine incorporation was significantly inhibited in cells grown in 450 mg/dl glucose, compared with cells grown in 100 mg/dl glucose. The cells grown in the higher glucose concentration were slightly larger, their protein content and the total protein synthetic rate were significantly increased, and they secreted approximately twice as much procollagens type IV and type I. Concordantly, steady-state procollagen mRNA levels were also increased: 2.6-fold for the alpha 1(IV) and 2.2-fold for the alpha 2(I) procollagens. Additionally, nuclear run-off studies demonstrated that procollagen gene transcription rate was stimulated approximately 50%; beta-actin transcription rate was not altered. We used chloramphenicol acetyltransferase (CAT) reporter gene constructs to determine whether the increased transcription rate of alpha 2(I) gene was associated with activation of its enhancer sequence. Cells transfected with the enhancer demonstrated more than fivefold increase in CAT activity when cultured in the high-glucose medium. These studies demonstrate a multitude of effects of high ambient glucose concentrations on proximal tubule cell growth and collagen biosynthesis; cell proliferation is decreased although cell hypertrophy occurs. Procollagen gene transcription rate is stimulated and this response contributes to the observed increase in procollagen mRNA content. Activation of an enhancer sequence may be one possible mode through which high glucose levels increase the transcription of procollagen type I, presumably involving trans-acting factor(s).