CHAPTER 10. Do Proteoglycans Mediate Chronic Photoaging

As well as collagen and elastin, glycosaminoglycans (GAGs) and proteoglycans (PGs) are abundant components in the extracellular matrix (ECM) in the skin. Hyaluronic acid (HA), dermatan sulfate (DS), chondroitin sulfate (CS), heparan sulfate (HS), heparin (HP), and keratin sulfate (KS) are six known members of GAGs, and numbers of their own partner PGs have been reported, except HA. Their structural and physiological roles are being revealed, and they are focused in these days as one of new targets for preventing or recovering skin aging. Understanding the complex interaction of GAGs and PGs with ECM components, specially, collagen and elastic fibers, may help us find new ideas to overcome the skin aging phenomenon. In this review, aging-related change of collagen and elastic fibers and glycosaminoglycan synthesis were simply explained as background, and the structural and physiological roles of skin-abundant GAGs and PGs, including hyaluronic acid, DS-PGs (decorin, biglycan, and others), CS-PGs (versican, CD44, and others), HS-PGs (perlecan and others), KS-PGs (lumican, osteoglycin, and fibromodulin), and their skin aging-related changes and possible involvements in the development of phenotypes of photoaging were summarized.