A decorin-deficient matrix affects skin chondroitin/dermatan sulfate levels and keratinocyte function.
Decorin is a small leucine-rich proteoglycan harboring a single glycosaminoglycan chain, which, in skin, is mainly composed of dermatan sulfate (DS). Mutant mice with targeted disruption of the decorin gene (Dcn(-/-)) exhibit an abnormal collagen architecture in the dermis and reduced tensile strength, collectively leading to a skin fragility phenotype. Notably, Ehlers-Danlos patients with mutations in enzymes involved in the biosynthesis of DS display a similar phenotype, and recent studies indicate that DS is involved in growth factor binding and signaling. To determine the impact of the loss of DS-decorin in the dermis, we analyzed the glycosaminoglycan content of Dcn(-/-) and wild-type mouse skin. The total amount of chondroitin/dermatan sulfate (CS/DS) was increased in the Dcn(-/-) skin, but was overall less sulfated with a significant reduction in bisulfated ΔDiS2,X (X=4 or 6) disaccharide units, due to the reduced expression of uronyl 2-O sulfotransferase (Ust). With increasing age, sulfation declined; however, Dcn(-/-) CS/DS was constantly undersulfated vis-à-vis wild-type. Functionally, we found altered fibroblast growth factor (Fgf)-7 and -2 binding due to changes in the micro-heterogeneity of skin Dcn(-/-) CS/DS. To better delineate the role of decorin, we used a 3D Dcn(-/-) fibroblast cell culture model. We found that the CS/DS extracts of wild-type and Dcn(-/-) fibroblasts were similar to the skin sugars, and this correlated with the lack of uronyl 2-O sulfotransferase in the Dcn(-/-) fibroblasts. Moreover, Ffg7 binding to total CS/DS was attenuated in the Dcn(-/-) samples. Surprisingly, wild-type CS/DS significantly reduced the binding of Fgf7 to keratinocytes in a concentration dependent manner unlike the Dcn(-/-) CS/DS that only affected the binding at higher concentrations. Although binding to cell-surfaces was quite similar at higher concentrations, keratinocyte proliferation was differentially affected. Higher concentration of Dcn(-/-) CS/DS induced proliferation in contrast to wild-type CS/DS. 3D co-cultures of fibroblasts and keratinocytes showed that, unlike Dcn(-/-) CS/DS, wild-type CS/DS promoted differentiation of keratinocytes. Collectively, our results provide novel mechanistic explanations for the reported defects in wound healing in Dcn(-/-) mice and possibly Ehlers-Danlos patients. Moreover, the lack of decorin-derived DS and an altered CS/DS composition differentially influence keratinocyte behavior.
Insitute of Physiological Chemistry and Pathobiochemistry, Waldeyerstr. 15, University Hospital Münster, University of Münster, D-48149 Münster, Germany.
Katerina
K
Nikolovska
Insitute of Physiological Chemistry and Pathobiochemistry, Waldeyerstr. 15, University Hospital Münster, University of Münster, D-48149 Münster, Germany.
Jana K
JK
Renke
Insitute of Physiological Chemistry and Pathobiochemistry, Waldeyerstr. 15, University Hospital Münster, University of Münster, D-48149 Münster, Germany.
Oliver
O
Jungmann
Insitute of Physiological Chemistry and Pathobiochemistry, Waldeyerstr. 15, University Hospital Münster, University of Münster, D-48149 Münster, Germany.
Kay
K
Grobe
Department of Pathology, Anatomy and Cell Biology, and the Cancer Cell Biology and Signaling Program, Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA, 19107, USA.
Renato V
RV
Iozzo
Department of Chemical and Biological Sciences, "Aurel Vlaicu" University of Arad, Romania and Mass Spectrometry Laboratory, National Institute for Research and Development in Electrochemistry and Condensed Matter, Timisoara, Romania.
Alina D
AD
Zamfir
Insitute of Physiological Chemistry and Pathobiochemistry, Waldeyerstr. 15, University Hospital Münster, University of Münster, D-48149 Münster, Germany. Electronic address: dgseidle@uni-muenster.de.
Daniela G
DG
Seidler
D000367:Age Factors; D000818:Animals; D015153:Blotting, Western; D018929:Cell Culture Techniques; D002809:Chondroitin Sulfates / Q000378:metabolism*; D017931:DNA Primers / Q000235:genetics; D058575:Decorin / Q000172:deficiency* / Q000235:genetics; D003871:Dermatan Sulfate / Q000031:analogs & derivatives* / Q000378:metabolism; D004535:Ehlers-Danlos Syndrome / Q000473:pathology; D005109:Extracellular Matrix / Q000378:metabolism*; D005455:Fluorescent Antibody Technique; D015603:Keratinocytes / Q000378:metabolism / Q000502:physiology*; D051379:Mice; D018345:Mice, Knockout; D060888:Real-Time Polymerase Chain Reaction; D012867:Skin / Q000166:cytology / Q000378:metabolism*
D017931:DNA Primers; C546879:Dcn protein, mouse; D058575:Decorin; C069524:dermatan sulfate chondroitin sulfate; D003871:Dermatan Sulfate; D002809:Chondroitin Sulfates
Decorin; Dermatan sulfate; Extracellular matrix; Fibroblast growth factor; SLRP