Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, Mississippi.
Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin.
J Am Soc Nephrol. 2020 Apr;31(4):687-700. doi: 10.1681/ASN.2019080784. Epub 2020 Feb 6.
The genes and mechanisms involved in the association between diabetes or hypertension and CKD risk are unclear. Previous studies have implicated a role for -adducin (ADD3), a cytoskeletal protein encoded by .
We investigated renal vascular function and and the susceptibility to CKD in rats with wild-type or mutated and in genetically modified rats with overexpression or knockout of ADD3. We also studied glomeruli and primary renal vascular smooth muscle cells isolated from these rats.
This study identified a K572Q mutation in ADD3 in fawn-hooded hypertensive (FHH) rats-a mutation previously reported in Milan normotensive (MNS) rats that also develop kidney disease. Using molecular dynamic simulations, we found that this mutation destabilizes a critical ADD3-ACTIN binding site. A reduction of ADD3 expression in membrane fractions prepared from the kidney and renal vascular smooth muscle cells of FHH rats was associated with the disruption of the F-actin cytoskeleton. Compared with renal vascular smooth muscle cells from transgenic rats, those from FHH rats had elevated membrane expression of BK and BK channel current. FHH and knockout rats exhibited impairments in the myogenic response of afferent arterioles and in renal blood flow autoregulation, which were rescued in transgenic rats. We confirmed these findings in a genetic complementation study that involved crossing FHH and MNS rats that share the ADD3 mutation. transgenic rats showed attenuation of proteinuria, glomerular injury, and kidney fibrosis with aging and mineralocorticoid-induced hypertension.
This is the first report that a mutation in ADD3 that alters ACTIN binding causes renal vascular dysfunction and promotes the susceptibility to kidney disease.
糖尿病或高血压与 CKD 风险之间的关联所涉及的基因和机制尚不清楚。先前的研究表明，细胞骨架蛋白 - 内收蛋白（ADD3）在其中起作用，该蛋白由 编码。
我们研究了野生型或突变型 大鼠的肾脏血管功能和 CKD 易感性，以及 ADD3 过表达或敲除的基因修饰大鼠。我们还研究了从这些大鼠分离的肾小球和原代肾血管平滑肌细胞。
本研究在 fawn-hooded 高血压（FHH）大鼠中发现了 ADD3 中的 K572Q 突变-该突变先前在米兰正常血压（MNS）大鼠中报道过，这些大鼠也患有肾脏疾病。通过分子动力学模拟，我们发现该突变会破坏 ADD3-ACTIN 结合的关键位点。从 FHH 大鼠的肾脏和肾血管平滑肌细胞的膜部分制备物中发现 ADD3 表达减少与 F-肌动蛋白细胞骨架的破坏有关。与来自 转基因大鼠的肾血管平滑肌细胞相比，FHH 大鼠的 BK 和 BK 通道电流的膜表达升高。与 敲除大鼠相比，FHH 和 敲除大鼠的传入小动脉的肌原性反应和肾血流自动调节受损，而在 转基因大鼠中得到恢复。我们在涉及共享 ADD3 突变的 FHH 和 MNS 大鼠的遗传互补研究中证实了这些发现。随着年龄的增长和醛固酮诱导的高血压， 转基因大鼠的蛋白尿、肾小球损伤和肾脏纤维化减轻。
这是第一个报道 ADD3 突变改变 ACTIN 结合会导致肾脏血管功能障碍并促进肾脏疾病易感性的报告。
