Pastino Alexandra K, Greco Todd M, Mathias Rommel A, Cristea Ileana M, Schwarzbauer Jean E
Department of Molecular Biology, Princeton University, Washington Road, Princeton, NJ 08544-1014, USA.
Department of Molecular Biology, Princeton University, Washington Road, Princeton, NJ 08544-1014, USA.
Matrix Biol. 2017 May;59:39-53. doi: 10.1016/j.matbio.2016.07.003. Epub 2016 Jul 15.
Advanced glycation endproducts (AGEs) are a heterogeneous group of compounds that form via non-enzymatic glycation of proteins throughout our lifespan and at a higher rate in certain chronic diseases such as diabetes. AGEs contribute to the progression of fibrosis, in part by stimulating cellular pathways that affect gene expression. Long-lived ECM proteins are targets for non-enzymatic glycation but the question of whether the AGE-modified ECM leads to excess ECM accumulation and fibrosis remains unanswered. In this study, cellular changes due to AGE accretion in the ECM were investigated. Non-enzymatic glycation of proteins in a decellularized fibroblast ECM was achieved by incubating the ECM in a solution of methylglyoxal (MGO). Mass spectrometry of fibronectin (FN) isolated from the glycated matrix identified twenty-eight previously unidentified MGO-derived AGE modification sites including functional sites such as the RGD integrin-binding sequence. Mesangial cells grown on the glycated, decellularized matrix assembled increased amounts of FN matrix. Soluble AGE-modified bovine serum albumin (BSA) also stimulated FN matrix assembly and this effect was reduced by function-blocking antibodies against the receptor for AGE (RAGE). These results indicate that cells respond to AGEs by increasing matrix assembly and that RAGE is involved in this response. This raises the possibility that the accumulation of ECM during the progression of fibrosis may be enhanced by cell interactions with AGEs on a glycated ECM.
晚期糖基化终产物（AGEs）是一类异质性化合物，其在我们的一生中通过蛋白质的非酶糖基化形成，在某些慢性疾病（如糖尿病）中形成速率更高。AGEs部分通过刺激影响基因表达的细胞途径，促进纤维化进程。长寿的细胞外基质（ECM）蛋白是非酶糖基化的靶点，但AGE修饰的ECM是否导致ECM过度积累和纤维化的问题仍未得到解答。在本研究中，研究了由于ECM中AGEs积累导致的细胞变化。通过将脱细胞成纤维细胞ECM在甲基乙二醛（MGO）溶液中孵育，实现蛋白质的非酶糖基化。从糖基化基质中分离的纤连蛋白（FN）的质谱分析确定了28个以前未鉴定的MGO衍生的AGE修饰位点，包括功能性位点，如RGD整合素结合序列。在糖基化的脱细胞基质上生长的系膜细胞组装了更多的FN基质。可溶性AGE修饰的牛血清白蛋白（BSA）也刺激了FN基质组装，并且针对晚期糖基化终产物受体（RAGE）的功能阻断抗体降低了这种作用。这些结果表明，细胞通过增加基质组装对AGEs作出反应，并且RAGE参与了这种反应。这增加了在纤维化进程中，ECM的积累可能通过细胞与糖基化ECM上的AGEs相互作用而增强的可能性。
