Structural and Sequence Motifs in Dermatan Sulfate for Promoting Fibroblast Growth Factor-2 (FGF-2) and FGF-7 Activity

Abstract

Glycosaminoglycans have been implicated in the binding and activation of a variety of growth factors, cytokines, and chemokines. In this way, glycosaminoglycans are thought to participate in events such as development and wound repair. In particular, heparin and heparan sulfate have been well studied, and specific aspects of their structure dictate their participation in a variety of activities. In contrast, although dermatan sulfate participates in many of the same biological processes as heparin and heparan sulfate, the interactions of dermatan sulfate have been less well studied. Dermatan sulfate is abundant in the wound environment and binds and activates growth factors such as fibroblast growth factor-2 (FGF-2) and FGF-7, which are present during the wound repair process. To determine the minimum size and sulfation content of active dermatan sulfate oligosaccharides, dermatan sulfate was first digested and then separated by size exclusion high pressure liquid chromatography, and the activity to facilitate FGF-2 and FGF-7 was assayed by the cellular proliferation of cell lines expressing FGFR1 or FGFR2 IIIb. The minimum size required for the activation of FGF-2 was an octasaccharide and for FGF-7 a decasaccharide. Active fractions were rich in monosulfated, primarily 4-O-sulfated, disaccharides and iduronic acid. Increasing the sulfation to primarily 2/4-O-sulfated and 2/6-O-sulfated disaccharides did not increase activity. Cell proliferation decreased or was abolished with higher sulfated dermatan sulfate preparations. This indicated a preference for specific dermatan sulfate oligosaccharides capable of promoting FGF-2-and FGF-7-dependent cell proliferation. These data identify critical oligosaccharides that promote specific members of the FGF family that are important for wound repair and angiogenesis.Components of the extracellular matrix are broken down following injury or inflammation. These extracellular matrix products in turn participate in various phases of the wound repair process. Following injury, proteoglycans (PG) 1 and their glycosaminoglycan (GAG) chains are released and become soluble and abundant in fluids collected from wounds (1). Dermatan sulfate (DS) is the most common GAG in the skin and is estimated to comprise between 36 and 78% of the total sulfated GAG in wound fluid samples (1). DS consists of repeating disaccharide units of N-acetylgalactosamine and glucuronic acid (GlcA)-linked ␤134 and ␤133, respectively. Similar to modifications in heparin and heparan sulfate (HS) but distinct from the other chondroitin sulfates (CS), the GlcA of DS undergoes epimerization of the C-5 carbon, resulting in iduronic acid (IdoUA). In addition, sulfation modifications can occur at the 2-position of the uronic acid and at the 4-or 6-position of the N-acetylgalactosamine residue. GAGs and their PG core proteins participate in a variety of functions during wound healing, including binding multiple growth factors and promoting their activities (1-8). Of these activities, the fibroblast growth factor ...

Inhibition or Activation of Apert Syndrome FGFR2 (S252W) Signaling by Specific Glycosaminoglycans

“…CS-B (2 g/ml) and FGF7 (Fig. 1B) also showed a detectable mitogenic activity on wild-type FGFR2b, which is consistent with previous reports (22,23). However, FGFR2b (S252W) preferentially responded to distinct GAGs in the presence of the three FGFs (Fig.…”

“…2 and 4). 2) CS-B was not restricted to activate wild-type FGFR2b with FGF2 or FGF7 as reported in the past (22,23,29). It also activated wild-type FGFR2c (Fig.…”

“…In contrast, mice deficient in HS and CS show defects in FGF signaling during gastrulation (15,17,18). Therefore heparin is not biologically relevant, but HS and CS are (22,23,29). Kidney HS has unique 3-O-sulfated sequences that are different from that of 3-O-sulfated heparin (30).…”

Demonstration of the Pleiotrophin-binding Oligosaccharide Sequences Isolated from Chondroitin Sulfate/Dermatan Sulfate Hybrid Chains of Embryonic Pig Brains

“…The smallest oligosaccharides in the chondroitinase B digest of E-CS/DS, which bound to PTN at a physiological salt concentration, were octasaccharides, although stronger interactions were observed with decasaccharides or larger oligosaccharides. This size dependence is reminiscent of the interactions of GAG oligosaccharides with other heparin-binding growth factors such as fibroblast growth factor (FGF) 1 (36), FGF2 (36,37), FGF4 (38), FGF7 (37), and hepatocyte growth factor (39).…”

Identification and Functions of Chondroitin Sulfate in the Milieu of Neural Stem Cells

“…Recently, it was reported that DS promotes FGF-2-dependent HSdeficient lymphoid cell proliferation, and the minimal size required for activation of FGF-2 was an octasaccharide (52). To examine whether any functional domain exists in the CS polysaccharides, an inhibition assay for their activities to promote FGF-2-mediated cell proliferation would be useful using CS-E-derived oligosaccharides with various structural features.…”