Department of Pharmaceutical Biochemistry, Wroclaw Medical University, Wroclaw, Poland.
Department of Pharmaceutical Biochemistry, Wroclaw Medical University, Wroclaw, Poland.
Arch Med Res. 2014 Jan;45(1):36-43. doi: 10.1016/j.arcmed.2013.10.003. Epub 2013 Dec 5.
Hyperglycemia and oxidative stress in type 2 diabetes (T2DM) provoke neutrophil overstimulation and the release and/or translocation of proteases from granules to the cell surface. Although the expression of neutrophil membrane-bound elastase (MLE) is well documented, the presence of the membrane-bound form of cathepsin B (MCB) is unknown. The aim of our study was to evaluate the neutrophil MLE and MCB activities in T2DM patients and their associations with the metabolic and clinical parameters of the disease.
Neutrophils were obtained from 47 T2DM patients and 20 control subjects. The activities of MLE and MCB and the intracellular activities of the examined proteases (ILE and ICB, respectively) were measured using fluorometric substrates. Additionally, the percentage equivalents of the activities, namely, MLEtot/ILEtot and MCBtot/ICBtot, were calculated. The susceptibility to inhibitors of both forms of the studied proteases was also determined.
A significant increase in the activities of MLE, MCB, ILE, and ICB was found in neutrophils from T2DM patients compared with the control group. The percentage equivalent (contribution of the total membrane-bound activities to the total intracellular activities) was also higher. A partial resistance of the membrane-bound forms toward their inhibitors was revealed. Higher activities of both the membrane-bound and the intracellular proteases were also observed in patients with poor glycemic and metabolic control. The differences between subgroups with different therapeutic schemes were also revealed.
The pathophysiological implications of the neutrophil membrane-bound forms of leukocyte elastase and cathepsin B are of great importance in the development of T2DM and its complications.
2 型糖尿病（T2DM）中的高血糖和氧化应激会刺激中性粒细胞过度激活，并导致蛋白酶从颗粒释放和/或转移到细胞表面。尽管中性粒细胞膜结合弹性蛋白酶（MLE）的表达已有充分的研究，但膜结合形式的组织蛋白酶 B（MCB）的存在情况尚不清楚。我们的研究目的是评估 T2DM 患者中性粒细胞 MLE 和 MCB 的活性，并研究其与疾病代谢和临床参数的关系。
从 47 例 T2DM 患者和 20 例对照者中获得中性粒细胞。使用荧光底物测量 MLE 和 MCB 的活性以及被检查蛋白酶（ILE 和 ICB）的细胞内活性。此外，还计算了活性的百分比等效物，即 MLEtot/ILEtot 和 MCBtot/ICBtot。还确定了两种形式的研究蛋白酶抑制剂的敏感性。
与对照组相比，T2DM 患者的中性粒细胞中 MLE、MCB、ILE 和 ICB 的活性显著增加。百分比等效物（总膜结合活性对总细胞内活性的贡献）也更高。发现两种形式的膜结合蛋白酶均具有部分抗性。血糖和代谢控制较差的患者的膜结合和细胞内蛋白酶活性也更高。还揭示了不同治疗方案亚组之间的差异。
中性粒细胞白细胞弹性蛋白酶和组织蛋白酶 B 的膜结合形式的病理生理意义在 T2DM 及其并发症的发展中非常重要。
