Dysfunction of dermal fibroblasts induced by advanced glycation end-products (AGEs) and the contribution of a nonspecific interaction with cell membrane and AGEs.

Advanced glycation end-products (AGEs) have been reported to accumulate in the dermal skin. However, it remains unknown whether the AGEs interact with the dermal fibroblasts and influence their function. Previously, we demonstrated that AGEs hastened photoaging of the skin by means of active oxygen species such as *O(2)(-), H(2)O(2), and *OH, generated during UVA irradiation. The purpose of the present study was to clarify the influence of AGEs on the functions of dermal fibroblasts under physiological conditions. It was found that AGEs decreased both hyaluronic acid (HA) synthesis and activity of elastase-type matrix metalloproteinase (ET-MMP). Because the reactions of both HA synthesis and ET-MMP were found to take place at the cell membrane region, it appeared that AGEs modulated cellular dysfunction through an interaction with the cell membrane. To clarify the mechanisms of these dysfunction in relation to AGEs, we examined the interaction between AGEs and cell membranes, and obtained the following results: (1) AGEs associated with the cell membranes and liposomal membrane prepared with phosphatidyl choline; (2) AGEs hydrophobically modified the circumstances of the cell membrane and liposome membrane as evaluated by experiments using a fluorescence probe; (3) AGEs increased the fluidity of the cell membrane and liposomal membrane as estimated by ESR spin-labeling using 5-doxylstearic acid; and (4) AGEs accelerated lactate dehydrogenase (LDH) leakage from the cells. On the basis of these experimental results, we proposed that AGEs modulated cell function through a nonspecific interaction with the membranes of dermal fibroblasts.