The Dermatan Sulfate Proteoglycan Decorin Modulates α2β1 Integrin and the Vimentin Intermediate Filament System during Collagen Synthesis

Abstract

Decorin, a small leucine-rich proteoglycan harboring a dermatan sulfate chain at its N-terminus, is involved in regulating matrix organization and cell signaling. Loss of the dermatan sulfate of decorin leads to an Ehlers-Danlos syndrome characterized by delayed wound healing. Decorin-null (Dcn−/−) mice display a phenotype similar to that of EDS patients. The fibrillar collagen phenotype of Dcn−/− mice could be rescued in vitro by decorin but not with decorin lacking the glycosaminoglycan chain. We utilized a 3D cell culture model to investigate the impact of the altered extracellular matrix on Dcn−/− fibroblasts. Using 2D gel electrophoresis followed by mass spectrometry, we identified vimentin as one of the proteins that was differentially upregulated by the presence of decorin. We discovered that a decorin-deficient matrix leads to abnormal nuclear morphology in the Dcn−/− fibroblasts. This phenotype could be rescued by the decorin proteoglycan but less efficiently by the decorin protein core. Decorin treatment led to a significant reduction of the α2β1 integrin at day 6 in Dcn−/− fibroblasts, whereas the protein core had no effect on β1. Interestingly, only the decorin core induced mRNA synthesis, phosphorylation and de novo synthesis of vimentin indicating that the proteoglycan decorin in the extracellular matrix stabilizes the vimentin intermediate filament system. We could support these results in vivo, because the dermis of wild-type mice have more vimentin and less β1 integrin compared to Dcn−/−. Furthermore, the α2β1 null fibroblasts also showed a reduced amount of vimentin compared to wild-type. These data show for the first time that decorin has an impact on the biology of α2β1 integrin and the vimentin intermediate filament system. Moreover, our findings provide a mechanistic explanation for the reported defects in wound healing associated with the Dcn−/− phenotype.

Flow induces epithelial-mesenchymal transition, cellular heterogeneity and biomarker modulation in 3D ovarian cancer nodules

“…A corresponding significant decrease in 3D tumor volume and viability was observed in 3D nodules grown under flow. These findings are consistent with the decreased proliferation that is a characteristic of EMT (30,32,(35)(36)(37) and the high attrition rates that metastatic nodules experience as they cope with the physical and biological stresses associated with colonizing distant sites (1,6,67,68 Fractal dimension (a ratio describing how an object fills space out to its maximum radius with a value of 1 describing a line and a value of 2 a circle) was used to quantify the morphological features of 3D tumors grown under flow versus nonflow conditions. Fractal dimension was significantly lower under flow (1.78 ± 0.01, n = 8 fields) than in nonflow (1.87 ± 0.01, n = 6 fields) conditions (P < 0.05), supporting the observation that flow induces morphological changes consistent with increased EMT in 3D tumors.…”

“…Decreased E-cadherin expression also is a hallmark of epithelial-to-mesenchymal transition (EMT) (26)(27)(28)(29)(30), a critical step in metastatic progression and a prognostic indicator of aggressive and refractory disease (31)(32)(33)(34)(35). Along with loss of E-cadherin, EMT is characterized by a range of molecular and morphological features, including the acquisition of a motile and mesenchymal phenotype with increased spindle-like morphology as well as increased expression of vimentin, an intermediate filament that maintains cell and tissue integrity and helps confer resistance to mechanical stress (30,32,(35)(36)(37). The cell-cycle regulator p27Kip1 modulates proliferation, motility, and apoptosis by inhibiting an array of cyclindependent kinases including cell-division control protein kinase 2 (CDC2) and also plays a role in cytoskeletal remodeling (38,39).…”

Chondroitin/dermatan 2-O sulfotransferase potentiates Fgf2 induced cell migration

“…Recently, the small non-coding microRNA149 has been linked to a new fine-tuning element of Fgf2-induced proliferation in endothelial cells by regulating the HS proteoglycan glypican (Chamorro-Jorganes et al, 2014). We have previously shown that the lack of decorin in skin led to the reduction of Ust and an impaired cell morphology in a 3D environment (Nikolovska et al, 2014;Jungmann et al, 2012), which could partially contribute to the delayed wound healing of the Dcn 2/2 mice (Järveläinen et al, 2006). We proved the importance of 2-O sulfation by showing that there was an impaired migration of 3T3 cells with a knockdown of Ust.…”

Decorin Potentiates Interferon-γ Activity in a Model of Allergic Inflammation

“…Along these lines, PMNs derived from this mouse show increased adhesion to blood vessels during intravital microscopy (26). Whereas the decorin-de- (42,59). The CD3⑀ stimulation may lead to changes on the cell surface that result in a decrease of activity.…”

“…Purification and characterization of the biologically active decorin protein core were described before (41). Samples were analyzed as described before and had no detectable levels of endotoxins (42). The following substances were used: CS4S and CS6S (Sigma), murine recombinant cytokines IFN-␥ and TNF-␣ (R&D Systems), and mrCXCL-10 (eBiosciences).…”