Croes Cresci-Anne C C, Chrysanthou Marialena, Hoppenbrouwers Tamara, Wichers Harry, Keijer Jaap, Savelkoul Huub F J, Teodorowicz Malgorzata
Department of Cell Biology and Immunology, Wageningen University and Research Centre, 6700 AH Wageningen, The Netherlands.
Department of Food Quality and Design, Wageningen University and Research Centre, 6708 WG Wageningen, The Netherlands.
Biomolecules. 2024 Nov 23;14(12):1492. doi: 10.3390/biom14121492.
Advanced glycation end-products (AGEs) are products of a non-enzymatic reaction between amino acids and reducing sugars. Glycated human serum albumin (HSA) increases in diabetics as a consequence of elevated blood glucose levels and glycating metabolites like methylglyoxal (MGO). The impact of different types of glycation on the immunomodulatory properties of HSA is poorly understood and is studied here. HSA was glycated with D-glucose, MGO, or glyoxylic acid (CML). Glycation-related biochemical changes were characterized using various biochemical methods. The binding of differentially glycated HSA to AGE receptors was determined with inhibition ELISAs, and the impact on inflammatory markers in macrophage cell line THP-1 and adherent monocytes isolated from human peripheral blood mononuclear cells (PBMCs) was studied. All glycation methods led to unique AGE profiles and had a distinct impact on protein structure. Glycation resulted in increased binding of HSA to the AGE receptors, with MGO modification showing the highest binding, followed by glucose and, lastly, CML. Additionally, modification of HSA with MGO led to the increased expression of pro-inflammatory markers in THP-1 macrophages and enhanced phosphorylation of NF-κB p65. The same pattern, although less prominent, was observed for HSA glycated with glucose and CML, respectively. An increase in pro-inflammatory markers was also observed in PBMC-derived monocytes exposed to all glycated forms of HSA, although HSA-CML led to a significantly higher inflammatory response. In conclusion, the type of HSA glycation impacts immune functional readouts with potential relevance for diabetes.
晚期糖基化终末产物（AGEs）是氨基酸与还原糖之间非酶促反应的产物。由于血糖水平升高以及甲基乙二醛（MGO）等糖化代谢产物增加，糖尿病患者体内糖化人血清白蛋白（HSA）水平会升高。不同类型的糖化作用对HSA免疫调节特性的影响尚不清楚，本文对此展开研究。HSA分别与D-葡萄糖、MGO或乙醛酸（CML）进行糖化反应。运用多种生化方法对糖化相关的生化变化进行表征。通过抑制性酶联免疫吸附测定法确定不同糖化形式的HSA与AGE受体的结合情况，并研究其对巨噬细胞系THP-1以及从人外周血单核细胞（PBMC）分离出的贴壁单核细胞中炎症标志物的影响。所有糖化方法均导致独特的AGE谱，并对蛋白质结构产生明显影响。糖化作用导致HSA与AGE受体的结合增加，其中MGO修饰的结合力最高，其次是葡萄糖，最后是CML。此外，用MGO修饰HSA会导致THP-1巨噬细胞中促炎标志物表达增加，并增强核因子κB p65的磷酸化。葡萄糖和CML糖化的HSA分别观察到相同的模式，尽管不太明显。在暴露于所有糖化形式HSA的PBMC来源单核细胞中也观察到促炎标志物增加，尽管HSA-CML导致的炎症反应明显更高。总之，HSA的糖化类型会影响免疫功能读数，这可能与糖尿病有关。
