Endogenous DNA damage clusters in human skin, 3-D model, and cultured skin cells
Endogenous DNA damage clusters in human skin, 3-D model, and cultured skin cells
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DOI：
10.1016/j.freeradbiomed.2005.05.008
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发表时间：
2005-09-15
影响因子：
7.4
通讯作者：
Sutherland, BM
中科院分区：
文献类型：
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作者：
Bennett, PV;Cuomo, NL;Sutherland, BM
簇状损伤（两个或多个氧化碱基、无碱基位点或相对 DNA 链上几个螺旋圈内的链断裂）是通过电离辐射在 DNA 中形成的。细胞簇很难修复，因此对基因组完整性构成重大挑战。尽管在一些永久性人类细胞系中发现了内源性簇，但尚不清楚簇是否在人体组织或原代细胞中积累。使用高灵敏度凝胶电泳、电子成像和数均长度分析，我们测定了人类皮肤、3D 皮肤模型和原代培养皮肤细胞中 DNA 的内源簇水平。来自人类皮肤真皮和表皮的 DNA 含有极低水平的内源簇（每千兆碱基几个）。然而，培养的皮肤成纤维细胞和角质形成细胞——无论是单层培养物还是3D模型皮肤培养物——都会积累氧化嘧啶、氧化嘌呤和脱碱基簇。在硒存在下生长细胞或增加细胞内 Fpg 蛋白水平（可能是通过增加簇损伤的处理）可降低内源簇的水平。这些结果意味着内源簇的水平会受到细胞外部环境及其处理 DNA 损伤的能力的影响。由爱思唯尔公司出版
Clustered damages-two or more oxidized bases, abasic sites, or strand breaks on opposing DNA strands within a few helical turns-are formed in DNA by ionizing radiation. Clusters are difficult for cells to repair and thus pose significant challenges to genomic integrity. Although endogenous clusters were found in some permanent human cell lines, it was not known if clusters accumulated in human tissues or primary cells. Using high-sensitivity gel electrophoresis, electronic imaging, and number average length analysis, we determined endogenous cluster levels in DNA from human skin, a 3-D skin model, and primary cultured skin cells. DNA from dermis and epidermis of human skin contained extremely low levels of endogenous clusters (a few per gigabase). However, cultured skin fibroblasts and keratinocytes-whether in monolayer cultures or in 3-D model skin cultures-accumulated oxidized pyrimidine, oxidized purine, and abasic clusters. The levels of endogenous clusters were decreased by growing cells in the presence of selenium or by increasing cellular levels of Fpg protein, presumably by increasing processing of clustered damages. These results imply that the levels of endogenous clusters can be affected by the cells' external environment and their ability to deal with DNA damage. Published by Elsevier Inc.