Kasinath B S, Grellier P, Choudhury G G, Abboud S L
Department of Medicine, University of Texas Health Science Center, San Antonio 78284, USA.
J Cell Physiol. 1996 Apr;167(1):131-6. doi: 10.1002/(SICI)1097-4652(199604)167:1<131::AID-JCP15>3.0.CO;2-E.
Proteinuria in diabetic nephropathy has been correlated with reduction in heparan sulfate proteoglycan (HSPG) content of the glomerular basement membrane. We have previously shown that the underlying mechanism probably involves reduction in the synthesis by glomerular epithelial cells. In this study we explored whether high glucose medium regulates basement membrane HSPG gene expression. Northern analysis demonstrated that rat glomerular epithelial cells in vitro constitutively express mRNA for basement membrane HSPG, similar to that observed in rat kidney glomerulus. RNase protection assay showed that incubation of glomerular epithelial cells with 30 mM glucose for 24 h and 7 days resulted in reduction in HSPG mRNA abundance. The decrease in mRNA abundance correlated with reduction in the synthesis of 35SO4-labeled basement membrane HSPG as measured by immunoprecipitation. Reduction in synthesis of HSPG could not be entirely accounted for by decrease in mRNA abundance, suggesting both transcriptional and posttranscriptional mechanisms may be involved in reduction of glomerular basement membrane HSPG synthesis by glomerular epithelial cells in diabetic nephropathy.
糖尿病肾病中的蛋白尿与肾小球基底膜硫酸乙酰肝素蛋白聚糖（HSPG）含量的降低相关。我们之前已表明其潜在机制可能涉及肾小球上皮细胞合成的减少。在本研究中，我们探究了高糖培养基是否调节基底膜HSPG基因表达。Northern分析表明，体外培养的大鼠肾小球上皮细胞组成性表达基底膜HSPG的mRNA，类似于在大鼠肾小球中观察到的情况。核糖核酸酶保护分析显示，将肾小球上皮细胞与30 mM葡萄糖孵育24小时和7天会导致HSPG mRNA丰度降低。mRNA丰度的降低与通过免疫沉淀法测定的35SO4标记的基底膜HSPG合成减少相关。HSPG合成的减少不能完全由mRNA丰度的降低来解释这一现象，提示转录和转录后机制可能均参与了糖尿病肾病中肾小球上皮细胞导致的肾小球基底膜HSPG合成减少。
