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研究显示,蛋白质异常修饰形成的寡聚体,与其多聚体、淀粉样纤维相比,具有更强的细胞毒性.这一发现被认为是蛋白质错误折叠和聚集研究领域中的重要进展.蛋白质的异常修饰如还原糖的非酶糖基化,是糖尿病最基本的病理特征.2型糖尿病患者尿液中的核糖浓度显著升高,表明糖尿病不仅与葡萄糖代谢紊乱相关,同时也与核糖代谢失调相关.以牛血清白蛋白(BSA)为研究对象,通过荧光分光光度计检测、原子力显微镜、透射电子显微镜观察以及分子排阻色谱分离,观察到核糖糖基化能够诱导BSA聚集,从单体、寡聚体逐渐形成多聚体.通过CCK-8 Kit、乳酸脱氢酶细胞活性检测、TUNEL染色、caspase-3活性检测以及流式细胞检测等方法,发现核糖糖基化的BSA单体对SH-SY5Y细胞(人神经母细胞瘤细胞系)具有明显的毒性,与此同时,糖化寡聚体和多聚体没有表现出显著的毒性.进一步研究发现,核糖糖基化的BSA单体通过与AGEs的受体RAGE相互作用,激活细胞内的MAPK通路,从而导致细胞凋亡.
Studies have shown that oligomers formed by aberrant protein modifications are more cytotoxic than their multimers, amyloid fibers, and are found to be important advances in the field of protein misfolding and aggregation. Abnormal modifications such as non-enzymatic glycosylation of reducing sugars are the most basic pathological features of diabetes.Decreased levels of ribose in urine of patients with type 2 diabetes mellitus indicate that diabetes is not only associated with glucose metabolism disorders but also with ribose metabolism disorders Using bovine serum albumin (BSA) as the research object, it was observed that the glycosylation of ribosylation could induce the aggregation of BSA by fluorescence spectrophotometer, atomic force microscopy, transmission electron microscopy and molecular exclusion chromatography, Aggregates gradually formed multimers.Using CCK-8 Kit, lactate dehydrogenase cell activity test, TUNEL staining, caspase-3 activity assay and flow cytometry, we found that ribosylation of BSA monomer on SH- SY5Y cells (human neuroblastoma cell lines) have significant toxicity, while glycated oligomers and multimers do not show significant toxicity. Further studies Found that glycosylation of the nucleus by receptor-BSA monomer RAGE interaction with AGEs, activation of MAPK pathway in the cell, leading to apoptosis.