Expression of decorin and collagens I and III in different layers of human skin in vivo: a laser capture microdissection study

Abstract

Extracellular matrix (ECM) organization is a complex process that requires the coordinated efforts of many molecules. For the regulation of collagen fiber diameter, the proteoglycan decorin appears to be of major relevance. To investigate the role of decorin in the process of (photo-)aging in more detail, full-thickness punch biopsies were isolated from human buttock skin. Single exposure with two minimal erythemal doses of solar simulated irradiation caused down-regulation of decorin mRNA in young (n = 5) and old subjects (n = 5) after 24 h. Interestingly, decorin mRNA was elevated with age. To test the hypothesis that a decreased collagen-to-decorin-ratio impairs collagen structure we also investigated collagens I and III gene expression. Both were down-regulated with increasing age and after single UV-irradiation. As determined by laser capture microdissection-quantitative real time-Polymerase chain reaction (n = 11), decorin is mostly present in the reticular dermis while being absent from the papillary dermis. Minor expression was also observed in the epidermis. However, in contrast to full-thickness skin biopsies age-dependent changes in collagens I, III, and decorin expression could not be observed with this methodology indicating technical limitations. Together with our finding that collagens I and III mRNA are similarly expressed in the reticular and papillary dermis and are down-regulated by UV, our studies support the idea of a major role of decorin in ECM organization. Altered expression of decorin mRNA in the different dermal strata and a decrease in the collagen-to-decorin ratio inflicted by both age and ultraviolet irradiation possibly affect collagen bundle diameter and subsequently the mechanical properties of human skin.

Reactivating the extracellular matrix synthesis of sulfated glycosaminoglycans and proteoglycans to improve the human skin aspect and its mechanical properties

“…Indeed, collagen disorganization and degradation was found in tissues having either truncated decorin core protein (as a consequence of UV irradiation32 or genetic disorders31) or altered sGAG chains (in aged skin) 33,34. It has been shown that the level of mRNA expression of decorin is also impacted by aging and by UV irradiation 35. In our study, we have shown that the composition once topically applied on a 41-year-old skin explant was able to stimulate both decorin component expression such as core protein (Figure 5) and chondroitin sulfate (Figure 3A).…”

Solar Ultraviolet Irradiation Induces Decorin Degradation in Human Skin Likely via Neutrophil Elastase

“…Non-glycanated decorin is comprised of the core protein, which contains oligosaccharide chains of varying lengths. In contrast to collagen, relatively little is known regarding the effects of UV irradiation on the levels and metabolism of decorin in human skin [24], [25].…”

Dermatopathology – the link between ancillary techniques and clinical lesions

“…Transition from precancerous to neoplastic cells can be confirmed within a single tissue sample, as has been shown in people with nevi cells transitioning into melanoma . LCM also allows evaluation of extracellular matrix proteins; for example, it was reported that decorin, a major protein involved in regulation of collagen fibre diameter, is expressed in reticular dermis, but absent in papillary dermis . The difference in decorin mRNA expression may contribute to the age and UV irradiation induced decrease of collagen I and IV by affecting bundle diameter in the superficial dermis.…”