Howard E W, Benton R, Ahern-Moore J, Tomasek J J
Department of Pathology, University of Oklahoma Health Sciences Center, Oklahoma City 73104, USA.
Exp Cell Res. 1996 Oct 10;228(1):132-7. doi: 10.1006/excr.1996.0308.
High glucose concentrations associated with diabetes have been shown to cause the nonenzymatic modification of proteins. Reducing sugars covalently bind to free amine groups, undergo Amadori rearrangements, and crosslink with other glucose-modified proteins. Crosslinking of type I collagen by incubation with different concentrations of glucose 6-phosphate for up to 5 days resulted in a nondeformable collagen lattice as assayed by physical compaction analysis. Nonglycated collagen was fully compactible. Fibroblasts cultured on nonglycated collagen lattices were able to contract the lattice over a 5-day period, while fibroblasts on collagen glycated with 50 mM or more glucose 6-phosphate were unable to do this. Cells on both nonglycated and glycated collagen lattices initially lacked organized bundles of actin microfilaments or stress fibers. Over time, the cells on glycated lattices formed stress fibers, suggesting that they were still exerting mechanical force on a nondeformable matrix. These results suggest that crosslinking of collagen fibrils by nonenzymatic glycation alters the physical properties of the extracellular matrix, resulting in changes in the organization of the intracellular actin cytoskeleton.
已证明与糖尿病相关的高血糖浓度会导致蛋白质的非酶修饰。还原糖与游离胺基共价结合，发生阿马多里重排，并与其他葡萄糖修饰的蛋白质交联。通过物理压实分析测定，将I型胶原蛋白与不同浓度的6-磷酸葡萄糖孵育长达5天，会导致形成不可变形的胶原晶格。未糖化的胶原蛋白是完全可压实的。在未糖化的胶原晶格上培养的成纤维细胞能够在5天内使晶格收缩，而在与50 mM或更高浓度的6-磷酸葡萄糖糖化的胶原蛋白上的成纤维细胞则无法做到这一点。未糖化和糖化胶原晶格上的细胞最初都缺乏有组织的肌动蛋白微丝束或应力纤维。随着时间的推移，糖化晶格上的细胞形成了应力纤维，这表明它们仍在对不可变形的基质施加机械力。这些结果表明，非酶糖基化导致的胶原纤维交联会改变细胞外基质的物理性质，从而导致细胞内肌动蛋白细胞骨架组织的变化。
