Department of Biochemistry, Medical University of Gdansk, Poland.
Jagiellonian Center for Experimental Therapeutics, Jagiellonian University, Krakow, Poland.
Biochim Biophys Acta Mol Basis Dis. 2017 Jun;1863(6):1464-1472. doi: 10.1016/j.bbadis.2017.02.008. Epub 2017 Feb 10.
Aortic stenosis is known to involve inflammation and thrombosis. Changes in activity of extracellular enzyme - ecto-5'-nucleotidase (referred also as CD73) can alter inflammatory and thrombotic responses. This study aimed to evaluate the effect of CD73 deletion in mice on development of aortic valve dysfunction and to compare it to the effect of high-fat diet. Four groups of mice (normal-diet Wild Type (WT), high-fat diet WT, normal diet CD73-/-, high-fat diet CD73-/-) were maintained for 15weeks followed by echocardiographic analysis of aortic valve function, measurement of aortic surface activities of nucleotide catabolism enzymes as well as alkaline phosphatase activity, mineral composition and histology of aortic valve leaflets. CD73-/- knock out led to an increase in peak aortic flow (1.06±0.26m/s) compared to WT (0.79±0.26m/s) indicating obstruction. Highest values of peak aortic flow (1.26±0.31m/s) were observed in high-fat diet CD73-/- mice. Histological analysis showed morphological changes in CD73-/- including thickening and accumulation of dark deposits, proved to be melanin. Concentrations of Ca, Mg and PO in valve leaflets were elevated in CD73-/- mice. Alkaline phosphatase (ALP) activity was enhanced after ATP treatment and reduced after adenosine treatment in aortas incubated in osteogenic medium. AMP hydrolysis in CD73-/- was below 10% of WT. Activity of ecto-adenosine deaminase (eADA), responsible for adenosine deamination, in the CD73-/- was 40% lower when compared to WT. Deletion of CD73 in mice leads to aortic valve dysfunction similar to that induced by high-fat diet suggesting important role of this surface protein in maintaining heart valve integrity.
主动脉瓣狭窄已知涉及炎症和血栓形成。细胞外酶-ecto-5'-核苷酸酶（也称为 CD73）活性的变化可改变炎症和血栓反应。本研究旨在评估 CD73 缺失对小鼠主动脉瓣功能障碍发展的影响，并将其与高脂肪饮食的影响进行比较。将四组小鼠（正常饮食野生型（WT）、高脂肪饮食 WT、正常饮食 CD73-/-、高脂肪饮食 CD73-/-）维持 15 周，然后进行主动脉瓣功能的超声心动图分析、测量主动脉表面核苷酸代谢酶的活性以及碱性磷酸酶活性、主动脉瓣叶的矿物质组成和组织学。CD73-/- 敲除导致峰值主动脉流量增加（1.06±0.26m/s），与 WT（0.79±0.26m/s）相比表明存在阻塞。高脂肪饮食 CD73-/- 小鼠观察到的峰值主动脉流量最高（1.26±0.31m/s）。组织学分析显示 CD73-/- 的形态变化，包括增厚和暗沉积物的积聚，被证明是黑色素。瓣膜小叶中的 Ca、Mg 和 PO 浓度在 CD73-/- 小鼠中升高。在骨形成培养基中孵育的主动脉中，用 ATP 处理后碱性磷酸酶（ALP）活性增强，用腺苷处理后降低。CD73-/- 中的 AMP 水解低于 WT 的 10%。与 WT 相比，CD73-/- 中的ecto-腺苷脱氨酶（eADA）活性降低了 40%，eADA 负责腺苷脱氨。CD73 缺失的小鼠导致主动脉瓣功能障碍类似于高脂肪饮食诱导的功能障碍，表明这种表面蛋白在维持心脏瓣膜完整性方面起着重要作用。
