Kidokoro Kengo, Satoh Minoru, Itano Seiji, Kuwabara Atsunori, Sasaki Tamaki, Kashihara Naoki
Department of Nephrology and Hypertension, Kawasaki Medical School, Japan.
Department of Nephrology and Hypertension, Kawasaki Medical School, Japan
J Renin Angiotensin Aldosterone Syst. 2016 May 23;17(2):1470320315625704. doi: 10.1177/1470320315625704. Print 2016 Apr-Jun.
We investigated the feasibility of using a fluorescence resonance energy transfer system to image enzymatic activity in order to evaluate the effects of aliskiren (a direct renin inhibitor) on diabetic nephropathy.
First, we induced diabetes in C57BL/6J mice using streptozotocin, then treated them with either aliskiren (25 mg/kg/day) or the angiotensin type 1 receptor blocker valsartan (15 mg/kg/day) for four weeks. Finally, we utilized renin fluorescence resonance energy transfer substrate to assess renin activity.
Renin activity was much higher in the kidneys of diabetic mice compared to those of the non-diabetic control mice. While aliskiren inhibited this activity, valsartan did not. We noted that production of reactive oxygen species intensified and the bioavailability of nitric oxide diminished in the glomeruli of diabetic mice. Aliskiren and valsartan significantly ameliorated these effects. They suppressed glomerular production of reactive oxygen species and urinary albumin excretion. In fact, urinary albumin excretion in diabetic mice treated with aliskiren or valsartan was lower than that in untreated diabetic mice. Furthermore, aliskiren and valsartan significantly reduced glomerular permeability by maintaining the glomerular endothelial surface layer.
Fluorescence resonance energy transfer could provide a new tool for evaluating tissue and plasma enzymatic activity.
我们研究了使用荧光共振能量转移系统对酶活性进行成像的可行性，以评估阿利吉仑（一种直接肾素抑制剂）对糖尿病肾病的影响。
首先，我们使用链脲佐菌素诱导C57BL/6J小鼠患糖尿病，然后用阿利吉仑（25毫克/千克/天）或1型血管紧张素受体阻滞剂缬沙坦（15毫克/千克/天）对它们进行为期四周的治疗。最后，我们利用肾素荧光共振能量转移底物来评估肾素活性。
与非糖尿病对照小鼠相比，糖尿病小鼠肾脏中的肾素活性要高得多。阿利吉仑可抑制这种活性，而缬沙坦则不能。我们注意到糖尿病小鼠肾小球中活性氧的产生增加，一氧化氮的生物利用度降低。阿利吉仑和缬沙坦可显著改善这些影响。它们抑制了肾小球活性氧的产生和尿白蛋白排泄。实际上，用阿利吉仑或缬沙坦治疗的糖尿病小鼠的尿白蛋白排泄低于未治疗的糖尿病小鼠。此外，阿利吉仑和缬沙坦通过维持肾小球内皮表面层显著降低了肾小球通透性。
荧光共振能量转移可为评估组织和血浆酶活性提供一种新工具。
