Heterogeneous vascular endothelial growth factor (VEGF) isoform mRNA and receptor mRNA expression in human glomeruli, and the identification of VEGF148 mRNA, a novel truncated splice variant
Heterogeneous vascular endothelial growth factor (VEGF) isoform mRNA and receptor mRNA expression in human glomeruli, and the identification of VEGF148 mRNA, a novel truncated splice variant
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DOI：
10.1042/cs19990016
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发表时间：
1999-09-01
期刊：
影响因子：
6
通讯作者：
Harper, SJ
中科院分区：
文献类型：
--
作者：
Whittle, C;Gillespie, K;Harper, SJ
血管内皮生长因子(VEGF)介导血管通透性增加和内皮细胞有丝分裂，并可能协调正常的肾小球通透性和蛋白尿。不同的异构体是差异基因剪接的结果。血管内皮生长因子与两种细胞表面酪氨酸激酶受体KDR和Flt-I(FMS样酪氨酸激酶-I)结合。后者也以可溶性形式(Sflt)存在，具有抑制作用。我们研究了单个正常人肾小球中血管内皮生长因子异构体及其受体的表达模式。将190个肾小球(20个个体)的mRNA收集在磁珠上，用血管内皮生长因子亚型和受体的引物进行巢式逆转录-聚合酶链式反应。同时进行CD45的巢式逆转录-聚合酶链式反应，以排除白细胞污染。意想不到的产物被分离、克隆和测序。肾小球血管内皮细胞生长因子mRWA亚型的表达有多种模式。最常见的是(58%)，所有三种常见形式都有表达。在肾小球中，63.00%、85.00%和84.00%的肾小球组织中均有血管内皮生长因子(189)的表达。此外，还发现了两种意想不到的聚合酶链式反应产物：18%的肾小球表达VEGF(145)，27%的肾小球表达一种新的截短的VEGF剪接变异体--VEGF(148)，缺失外显子6、外显子7末端和外显子8。总体而言，KDR出现在59%的肾小球中，Flt-I出现在45%，SFlt出现在57%。因此，血管内皮生长因子在正常肾小球中的表达是复杂和多变的，存在个体间和个体内的差异。此外，sFlt似乎是肾小球内表达的血管内皮生长因子受体的共同优势形式，这表明，在健康个体中，一定程度的血管内皮生长因子自我调节是正常的。血管内皮细胞生长因子(148)的生理意义仍有待证实。
Vascular endothelial growth factor (VEGF) mediates increased vascular permeability and endothelial mitogenesis, and may orchestrate normal glomerular permselectivity and proteinuria. Distinct isoforms result from differential gene splicing. VEGF binds to two cell surface tyrosine-kinase receptors, KDR (kinase domain region) and Flt-I (fms-like tyrosine kinase-I). The latter also exists in a soluble form (sFlt), which is inhibitory. We have studied patterns of VEGF-isoform and VEGF-receptor expression in isolated single normal human glomeruli. mRNA from 190 glomeruli (from 20 individuals) was harvested on to magnetic beads, and nested reverse transcription-PCR was performed using primers for the VEGF isoforms and VEGF receptors. Simultaneous nested reverse transcription-PCR for CD45 was conducted in order to exclude leucocyte contamination. Unexpected products were isolated, cloned and sequenced. Multiple patterns of glomerular VEGF mRWA isoform expression were identified. Most frequently (58%), all three common forms were expressed. VEGF(189) (i.e. 189-amino-acid form of VEGF) was expressed in 63%, VEGF(165) in 85% and VEGF(121) in 84% of glomeruli. Two unexpected PCR products were also identified: 18% of glomeruli expressed VEGF(145), and 27% of glomeruli expressed a new truncated VEGF splice variant, VEGF(148), lacking exon 6, the terminal part of exon 7 and exon 8. Multiple patterns of VEGF-receptor expression were also identified, the most common being expression of all three isoforms (28%). Overall, KDR was seen in 59% of glomeruli, Flt-I in 45% and sFlt in 57%. Thus the expression of VEGF within normal glomeruli is complex and variable, with inter- and intra-individual variation. Furthermore, sFlt appears to be the co-dominant form of VEGF receptor expressed within glomeruli, suggesting that, in healthy individuals, a degree of VEGF autoregulation is the norm. The physiological importance of VEGF(148) remains to be confirmed.