Microvascular Research Laboratories, Department Physiology and Pharmacology, Bristol Heart Institute, Preclinical Veterinary School, Southwell Street, Bristol, BS2 8EJ, UK.
J Am Soc Nephrol. 2010 Sep;21(9):1498-509. doi: 10.1681/ASN.2009060617. Epub 2010 Aug 5.
The observation that therapeutic agents targeting vascular endothelial growth factor-A (VEGF-A) associate with renal toxicity suggests that VEGF plays a role in the maintenance of the glomerular filtration barrier. Alternative mRNA splicing produces the VEGF(xxx)b family, which consists of antiangiogenic peptides that reduce permeability and inhibit tumor growth; the contribution of these peptides to normal glomerular function is unknown. Here, we established and characterized heterozygous and homozygous transgenic mice that overexpress VEGF(165)b specifically in podocytes. We confirmed excess production of glomerular VEGF(165)b by reverse transcriptase-PCR, immunohistochemistry, and ELISA in both heterozygous and homozygous animals. Macroscopically, the mice seemed normal up to 18 months of age, unlike the phenotype of transgenic podocyte-specific VEGF(164)-overexpressing mice. Animals overexpressing VEGF(165)b, however, had a significantly reduced normalized glomerular ultrafiltration fraction with accompanying changes in ultrastructure of the glomerular filtration barrier on the vascular side of the glomerular basement membrane. These data highlight the contrasting properties of VEGF splice variants and their impact on glomerular function and phenotype.
观察到针对血管内皮生长因子-A (VEGF-A) 的治疗药物与肾毒性相关，这表明 VEGF 在维持肾小球滤过屏障方面发挥作用。替代 mRNA 剪接产生了 VEGF(xxx)b 家族，其中包括抗血管生成肽，可降低通透性并抑制肿瘤生长；这些肽对正常肾小球功能的贡献尚不清楚。在这里，我们建立并表征了特异性在足细胞中过表达 VEGF(165)b 的杂合子和纯合子转基因小鼠。我们通过逆转录酶-PCR、免疫组织化学和 ELISA 在杂合子和纯合子动物中证实了肾小球 VEGF(165)b 的过量产生。宏观上，这些小鼠在 18 个月大之前看起来正常，与过表达足细胞特异性 VEGF(164)的转基因小鼠的表型不同。然而，过表达 VEGF(165)b 的动物的肾小球超滤分数明显降低，肾小球基底膜血管侧的肾小球滤过屏障的超微结构也发生了变化。这些数据突出了 VEGF 剪接变体的对比特性及其对肾小球功能和表型的影响。
