Renal Division, Washington University School of Medicine, St. Louis, MO 63110, USA.
J Am Soc Nephrol. 2010 Apr;21(4):579-86. doi: 10.1681/ASN.2009091004. Epub 2010 Feb 11.
Mutation of the mouse laminin alpha5 gene results in a variety of developmental defects, including defects in kidney structure and function. Whereas the total absence of laminin alpha5 results in breakdown of the glomerular basement membrane (GBM) and failed glomerular vascularization, a hypomorphic Lama5 mutation (the Lama5(neo) allele) results in proteinuria, hematuria, polycystic kidney disease (PKD), and death 3 to 4 weeks after birth. Here, we examined the role of podocyte-derived laminin alpha5 via podocyte-specific inactivation of Lama5 and podocyte-specific rescue of the Lama5(neo) mutation. Podocyte-specific inactivation of Lama5 resulted in varying degrees of proteinuria and rates of progression to nephrotic syndrome. The GBM of proteinuric mice appeared thickened and "moth-eaten," and podocyte foot processes became effaced. Podocyte-specific restoration of laminin alpha5 production using two distinct strategies in Lama5(neo/neo) mice resulted in the resolution of proteinuria, hematuria, and PKD. These results suggest that the development of normal GBM structure and function requires podocyte-derived laminin alpha5 during and after glomerulogenesis and present a unique mechanism for the pathogenesis of PKD in these mice.
突变的小鼠层粘连蛋白 α5 基因导致多种发育缺陷，包括肾脏结构和功能的缺陷。而层粘连蛋白 α5 的完全缺失会导致肾小球基底膜（GBM）的破坏和肾小球血管化失败，而一个低功能的 Lama5 突变（Lama5(neo)等位基因）会导致蛋白尿、血尿、多囊肾病（PKD），并在出生后 3 到 4 周死亡。在这里，我们通过足细胞特异性敲除 Lama5 和足细胞特异性拯救 Lama5(neo)突变，研究了足细胞源性层粘连蛋白 α5 的作用。Lama5 的足细胞特异性敲除导致不同程度的蛋白尿和发展为肾病综合征的速度。蛋白尿小鼠的 GBM 似乎增厚和“虫蚀样”，足细胞足突消失。在 Lama5(neo/neo)小鼠中使用两种不同策略特异性恢复层粘连蛋白 α5 的产生导致蛋白尿、血尿和 PKD 的缓解。这些结果表明，正常 GBM 结构和功能的发育需要在肾小球发生和发生后期间来自足细胞的层粘连蛋白 α5，并为这些小鼠中 PKD 的发病机制提供了一个独特的机制。
