The role of macromolecules in the formation of kidney stones.
The role of macromolecules in the formation of kidney stones.
复制标题
大分子在肾结石形成中的作用。
DOI：
10.1007/s00240-016-0948-8
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发表时间：
2017-02
期刊：
影响因子：
3.1
通讯作者：
Wesson JA
中科院分区：
文献类型：
--
作者：
Rimer JD;Kolbach-Mandel AM;Ward MD;Wesson JA
晶体聚集体的形成是肾结石发病机制中的关键过程之一，涉及晶体（主要是草酸钙一水合物，COM）和尿成分（例如蛋白质）之间的相互作用，其充当结石中晶体之间的粘合剂“胶水”。为了更好地了解导致晶体聚集的蛋白质-晶体相互作用，我们测量了模型蛋白质对大体积COM晶体性质的影响以及它们在晶体表面上的吸附，使用三种合成聚阴离子：聚（天冬氨酸）（polyD），聚（谷氨酸）（polyE）和聚（丙烯酸）（polyAA）。这些阴离子大分子减少COM晶体聚集在本体溶液中的量的程度类似于观察到的蛋白质的混合物从正常的尿液，聚合物之间的差异很小。相反，聚合物表现出COM晶体生长的措施的差异。聚阳离子，如聚（精氨酸）（polyR）和聚（赖氨酸）（polyK）减少聚集弱，对晶体生长的影响可以忽略不计。所有聚离子被发现与COM晶体表面，证明COM晶体的zeta电位在电泳迁移率测量的变化。另一方面，COM聚集和可能的增长可以促进许多二元混合物的聚阳离子和聚阴离子，这似乎是介导的聚合物聚集体的形成，而不是损失的晶体电荷稳定。类似地，晶体聚集促进行为可以通过形成弱电荷聚阴离子的聚集体来驱动，如Tamm-Horsfall蛋白质，这表明聚合物（蛋白质）聚集可能在结石形成中起关键作用。聚阴离子-COM晶体表面相互作用对聚合物侧基的化学组成的敏感性通过聚D和聚E之间的晶体聚集行为的巨大差异来证明，这与原子力显微镜（AFM）测量的各种COM表面上的生长抑制和化学力显微镜（CFM）COM晶体表面和修饰有羧酸盐或脒部分（分别模拟聚阴离子和聚R侧链）的AFM尖端之间的解结合力的测量。与polyD相比，polyE在COM（100）表面缺乏强相互作用似乎是关键差异。最后，聚阴离子和聚阳离子的同时存在似乎改变了聚阳离子介导CFM中的解束缚力和促进晶体生长的能力。总之，聚阴离子强烈与COM表面和影响结晶，而聚阳离子没有，虽然重要的差异，观察到的基础上的聚阴离子的物理化学性质。观察表明，COM聚集与聚阴离子-聚阳离子混合物和弱电荷的聚阴离子促进聚合物聚集体的形成，这起着至关重要的作用，在桥接晶体表面。
The formation of crystal aggregates, one of the critical processes in kidney stone pathogenesis, involves interactions between crystals (predominantly calcium oxalate monohydrate, COM) and urinary constituents (e.g. proteins), which serve as an adhesive “glue” between crystals in stones. To develop a better understanding of the protein-crystal interactions that lead to crystal aggregation, we have measured the effect of model proteins on bulk COM crystal properties as well as their adsorption on crystal surfaces using three synthetic polyanions: poly(aspartic acid) (polyD), poly(glutamic acid) (polyE), and poly(acrylic acid) (polyAA). These anionic macromolecules reduced the amount of COM crystal aggregation in bulk solution to an extent similar to that observed for mixture of proteins from normal urine, with little difference between the polymers. In contrast, the polymers exhibited differences in measures of COM crystal growth. Polycations such as poly(arginine) (polyR) and poly(lysine) (polyK) reduced aggregation weakly and exerted negligible effects on crystal growth. All polyions were found to associate with COM crystal surfaces, as evidenced by changes in the zeta potential of COM crystals in electrophoretic mobility measurements. On the other hand, COM aggregation and possibly growth can be promoted by many binary mixtures of polycations and polyanions, which appeared to be mediated by polymer aggregate formation rather than loss of crystal charge stabilization. Similarly, crystal aggregation promotion behavior can be driven by forming aggregates of weakly charged polyanions, like Tamm-Horsfall Protein, suggesting that polymer (protein) aggregation may play a critical role in stone formation. Sensitivity of polyanion–COM crystal surface interactions to the chemical composition of polymer side groups were demonstrated by large differences in crystal aggregation behavior between polyD and polyE, which correlated with atomic force microscopy (AFM) measurements of growth inhibition on various COM surfaces and chemical force microscopy (CFM) measurements of unbinding forces between COM crystal surfaces and AFM tips decorated with either carboxylate or amidinium moieties (mimicking polyanion and polyR side chains, respectively). The lack of strong interaction for polyE at the COM (100) surface compared to polyD appeared to be the critical difference. Finally, the simultaneous presence of polyanions and polycations appeared to alter the ability of polycations to mediate unbinding forces in CFM and promote crystal growth. In summary, polyanions strongly associated with COM surfaces and influenced crystallization, while polycations did not, though important differences were observed based on the physicochemical properties of polyanions. Observations suggest that COM aggregation with both polyanion–polycation mixtures and weakly charged polyanions is promoted by polymer aggregate formation, which plays a critical role in bridging crystal surfaces.