Department of Structural Pathology, Institute of Nephrology, Niigata University, Niigata, Japan.
Nephron Exp Nephrol. 2009;113(2):e45-56. doi: 10.1159/000228408. Epub 2009 Jul 10.
BACKGROUND/AIMS: A chemokine fractalkine (FKN/CX3CL1) is induced primarily by endothelial cells and accumulates inflammatory cells via its receptor CX3CR1. Since glomerular preferential expression of FKN/CX3CL1 gene was reported in normal human kidney, we presumed FKN/CX3CL1 might play some roles in glomerular physiology. The purpose of this study is to examine the expression and localization of FKN/CX3CL1 in normal and proteinuric glomeruli.
Normal and proteinuric rat kidneys were studied. The gene and protein expressions of FKN/CX3CL1 and CX3CR1 were examined by real-time RT-PCR, in situ hybridization and immunohistochemistry, Western blotting.
By real-time RT-PCR, glomerular preferential expression of FKN/CX3CL1 was confirmed, whereas CX3CR1 was detected in glomeruli and cortices. The localization of FKN/CX3CL1 gene and protein were demonstrated in glomerular cells including podocytes. In nephrotic puromycin aminonucleoside (PAN) nephrosis glomeruli, increased expression of FKN/CX3CL1 in podocyte was shown by immunohistochemistry. Western blotting showed that in nephrotic glomeruli, the membrane-anchored form of FKN/CX3CL1 was increased while the soluble form was decreased.
The expression of FKN/CX3CL1 in normal podocytes and the increased expression of the membrane-anchored form in nephrotic glomeruli strongly suggest that FKN/CX3CL1 may play roles in glomerular physiology such as maintaining glomerular filtration barrier.
背景/目的：趋化因子 fractalkine（FKN/CX3CL1）主要由内皮细胞诱导产生，并通过其受体 CX3CR1 聚集炎症细胞。由于在正常人类肾脏中已报道肾小球优先表达 FKN/CX3CL1 基因，我们推测 FKN/CX3CL1 可能在肾小球生理学中发挥某些作用。本研究旨在检查 FKN/CX3CL1 在正常和蛋白尿肾小球中的表达和定位。
研究了正常和蛋白尿大鼠的肾脏。通过实时 RT-PCR、原位杂交和免疫组织化学、Western blotting 检查了 FKN/CX3CL1 和 CX3CR1 的基因和蛋白表达。
通过实时 RT-PCR，证实了肾小球对 FKN/CX3CL1 的优先表达，而 CX3CR1 则在肾小球和皮质中检测到。肾小球细胞包括足细胞中的 FKN/CX3CL1 基因和蛋白的定位得到了证明。在肾病性嘌呤霉素氨基核苷（PAN）肾病肾小球中，免疫组织化学显示足细胞中 FKN/CX3CL1 的表达增加。Western blotting 显示在肾病性肾小球中，FKN/CX3CL1 的膜结合形式增加，而可溶性形式减少。
正常足细胞中 FKN/CX3CL1 的表达以及肾病性肾小球中膜结合形式的增加表明 FKN/CX3CL1 可能在肾小球生理学中发挥作用，例如维持肾小球滤过屏障。
