Mayflower Organization For Research and Education, Sunnyvale, California 94085, USA.
Metab Syndr Relat Disord. 2010 Aug;8(4):355-63. doi: 10.1089/met.2010.0011.
Signaling events associated with diabetic nephropathy are not well understood. Triangulation of events triggered by unrelated bioactive peptides nephrilin and anephril, both of which inhibit albuminuria in diabetic mice, could reveal a common subset of events associated with albuminuria.
db/db mice received 20 microg/day anephril or nephrilin for 7 weeks. Streptozotocin (STZ)-treated DBA/2J mice received 2 mg/kg nephrilin for 26 days. In both studies, urine albumin and creatinine, plasma glucose, and tissue proteins were measured by enzyme-linked immunosorbent assay (ELISA). In a safety study, DBA/2J mice received 20 mg/kg nephrilin for 26 days, and tissues from these mice were fixed in formalin for histological analysis. HEK293 human kidney cells were treated with glycated hemoglobin plus 20 microg/mL nephrilin or anephril for 24 h.
Both peptides reduced albuminuria in db/db mice compared to saline-treated animals without affecting plasma glucose or insulin. In kidney tissues, the immunoreactivities of insulin receptor substrate-2 (IRS2), phosphorylated protein kinase C (p-PKC), and serum- and glucocortocoid-inducible kinase (SGK1) were reduced. Nephrilin, but not anephril, lowered elevated SGK1 in spleens of db/db mice. In STZ-pretreated DBA/2J mice, nephrilin reduced albuminuria and the accumulation of nuclear Rictor, IRS2, and p-PKC in the kidney. In cultured kidney cells, nephrilin disrupted the association of Rictor with IRS2 and nuclear compartmentalization. Histopathological examination of tissues from mice treated with 20 mg/kg nephrilin daily for 26 days showed no significant pathology compared to saline-treated controls.
We define a subset of signaling markers closely associated with albuminuria. Mammalian target of rapamycin complex 2 (mTORC2)::IRS complexes may play a role in the nuclear accumulation, and possible downstream transcriptional effects, of p-PKC. The activity and apparent safety of nephrilin in rodents suggest a novel intervention strategy for diabetic kidney disease.
与糖尿病肾病相关的信号事件尚不清楚。与无关的生物活性肽 Nephrilin 和 Anephril 触发的事件的三角测量，这两种肽都能抑制糖尿病小鼠的白蛋白尿，可能揭示与白蛋白尿相关的共同事件子集。
db/db 小鼠每天接受 20 微克 Anephril 或 Nephrilin 治疗 7 周。链脲佐菌素（STZ）处理的 DBA/2J 小鼠接受 2 毫克/千克 Nephrilin 治疗 26 天。在这两项研究中，通过酶联免疫吸附试验（ELISA）测量尿液白蛋白和肌酐、血浆葡萄糖和组织蛋白。在一项安全性研究中，DBA/2J 小鼠接受 20 毫克/千克 Nephrilin 治疗 26 天，这些小鼠的组织用福尔马林固定用于组织学分析。用糖化血红蛋白加 20 微克/ml Nephrilin 或 Anephril 处理 HEK293 人肾细胞 24 小时。
与生理盐水处理的动物相比，两种肽均降低了 db/db 小鼠的白蛋白尿，而不影响血浆葡萄糖或胰岛素。在肾脏组织中，胰岛素受体底物-2（IRS2）、磷酸化蛋白激酶 C（p-PKC）和血清和糖皮质激素诱导激酶（SGK1）的免疫反应性降低。Nephrilin 但不是 Anephril，降低了 db/db 小鼠脾脏中升高的 SGK1。在 STZ 预处理的 DBA/2J 小鼠中，Nephrilin 降低了白蛋白尿和肾脏中核 Rictor、IRS2 和 p-PKC 的积累。在培养的肾细胞中，Nephrilin 破坏了 Rictor 与 IRS2 的关联和核区室化。与生理盐水处理的对照组相比，用 20 毫克/千克 Nephrilin 每天治疗 26 天的小鼠组织的组织病理学检查未显示出显著的病理学变化。
我们定义了与白蛋白尿密切相关的信号标记物的子集。雷帕霉素复合物 2（mTORC2）：IRS 复合物可能在 p-PKC 的核积累及其可能的下游转录效应中起作用。Nephrilin 在啮齿动物中的活性和明显的安全性表明，它可能是一种治疗糖尿病肾病的新干预策略。
