BACKGROUND The genes and mechanisms involved in the association between diabetes or hypertension and CKD risk are unclear. Previous studies have implicated a role for γ-adducin (ADD3), a cytoskeletal protein encoded by Add3. METHODS We investigated renal vascular function in vitro and in vivo and the susceptibility to CKD in rats with wild-type or mutated Add3 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. RESULTS 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 Add3 transgenic rats, those from FHH rats had elevated membrane expression of BKα and BK channel current. FHH and Add3 knockout rats exhibited impairments in the myogenic response of afferent arterioles and in renal blood flow autoregulation, which were rescued in Add3 transgenic rats. We confirmed these findings in a genetic complementation study that involved crossing FHH and MNS rats that share the ADD3 mutation. Add3 transgenic rats showed attenuation of proteinuria, glomerular injury, and kidney fibrosis with aging and mineralocorticoid-induced hypertension. CONCLUSIONS 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.

中文翻译：

---

γ-Adducin的突变会损害肾脏血流的自动调节并促进肾脏疾病的发展。

背景技术尚不清楚涉及糖尿病或高血压与CKD风险之间关联的基因和机制。先前的研究表明，γ-adducin（ADD3）是一种由Add3编码的细胞骨架蛋白。方法我们研究了野生型或突变的Add3大鼠和ADD3过表达或敲除的转基因大鼠在体外和体内的肾血管功能以及对CKD的敏感性。我们还研究了从这些大鼠中分离出的肾小球和原代肾血管平滑肌细胞。结果该研究在小鹿型高血压（FHH）大鼠中鉴定出ADD3中的K572Q突变-先前在米兰血压正常（MNS）大鼠中也报道过的突变，该突变也发​​展为肾脏疾病。使用分子动力学模拟，我们发现该突变使关键的ADD3-ACTIN结合位点不稳定。从FHH大鼠的肾脏和肾脏血管平滑肌细胞制备的膜级分中ADD3表达的减少与F-肌动蛋白细胞骨架的破坏有关。与来自Add3转基因大鼠的肾血管平滑肌细胞相比，来自FHH大鼠的那些具有升高的BKα膜表达和BK通道电流。FHH和Add3基因敲除大鼠在传入小动脉的肌源性反应和肾血流自动调节方面均表现出损伤，这在Add3转基因大鼠中得以挽救。我们在一项遗传互补研究中证实了这些发现，该研究涉及共享ADD3突变的FHH和MNS杂交大鼠。Add3转基因大鼠表现出蛋白尿减少，肾小球损伤和肾纤维化以及衰老和盐皮质激素诱发的高血压。