Dermatan sulfate activates nuclear factor-kappab and induces endothelial and circulating intercellular adhesion molecule-1.

Proteoglycans (PGs) can influence cell behaviors through binding events mediated by their glycosaminoglycan (GAG) chains. This report demonstrates that chondroitin sulfate B, also known as dermatan sulfate (DS), a major GAG released during the inflammatory phase of wound repair, directly activates cells at the physiologic concentrations of DS found in wounds. Cultured human dermal microvascular endothelial cells exposed to DS responded with rapid nuclear translocation of nuclear factor-kappaB (NF-kappaB), increased expression of intercellular adhesion molecule-1 (ICAM-1) mRNA, and increased ICAM-1 cell surface protein. Heparan sulfate and chondroitin sulfates A and C had no effect on activation of NF-kappaB or induction of ICAM-1. Inhibition of NF-kappaB activation blocked the effect of DS. The increase in cell surface ICAM-1 did not involve TNF-alpha or IL-1 release by endothelial cells, but it was facilitated by autocrine factors whose release was initiated by DS. The ICAM-1-inductive activity of DS was confirmed in vivo. Injection of DS, but not heparin or other chondroitin sulfates, into mice greatly increased circulating levels of soluble ICAM. These data provide evidence that DS, but not other GAGs, initiates a previously unrecognized cell signaling event that can act during the response to injury.

Dermatan sulfate released after injury is a potent promoter of fibroblast growth factor-2 function.

Proteoglycans have been shown in vitro to bind multiple components of the cellular microenvironment that function during wound healing. To study the composition and function of these molecules when derived from an in vivo source, soluble proteoglycans released into human wound fluid were characterized and evaluated for influence on fibroblast growth factor-2 activity. Immunoblot analysis of wound fluid revealed the presence of syndecan-1, syndecan-4, glypican, decorin, perlecan, and versican. Sulfated glycosaminoglycan concentrations ranged from 15 to 65 microgram/ml, and treatment with chondroitinase B showed that a large proportion of the glycosaminoglycan was dermatan sulfate. The total glycosaminoglycan mixture present in wound fluid supported the ability of fibroblast growth factor-2 to signal cell proliferation. Dermatan sulfate, and not heparan sulfate, was the major contributor to this activity, and dermatan sulfate bound FGF-2 with Kd = 2.48 microM. These data demonstrate that proteoglycans released during wound repair are functionally active and provide the first evidence that dermatan sulfate is a potent mediator of fibroblast growth factor-2 responsiveness.

A 70-kDa amino-terminal fibronectin fragment supports gelatin binding to macrophages and decreases gelatinase activity.

We previously reported that a macrophage response that increased binding to 125I-radiolabeled soluble denatured collagen (gelatin) was induced by preincubation of macrophage with a 70-kDa amino-terminal fibronectin fragment and soluble nonlabeled gelatin [S. F. Penc, F. A. Blumenstock, J. E. Kaplan (1995) J. Leukoc. Biol. 58, 501-509]. We now report that neither protein synthesis nor recycling of receptors between the cell surface and interior were required for this response. However, removal of cell surface components with trypsin demonstrated that induced gelatin binding required native cell surface constituents. It was found that in the presence of the 70-kDa fibronectin fragment and gelatin, matrix metalloprotease-2 (MMP-2) and matrix metalloprotease-9 (MMP-9) activity in the cell layers was significantly decreased or undetectable, respectively. Similar levels of increased gelatin binding could be reproduced after inhibition of matrix-degrading metalloprotease activity with 1'10-phenanthroline. These results demonstrate that a macrophage specific response that decreased gelatinase activity and increased gelatin binding was initiated by interaction with a 70-kDa fibronectin fragment and gelatin.

A role for a 70-kDa amino-terminal fibronectin fragment in supporting soluble gelatin interactions with rat peritoneal macrophages.

Seventy-kilodalton amino-terminal and 180-kDa cell-binding fibronectin fragments were used to determine which fibronectin domains support soluble gelatin interactions with macrophages. At each time measured, intact and 180-kDa fibronectin supported significantly larger quantities of cell-associated gelatin than control levels (P < 0.05). Throughout the time course fibronectin supported more binding than 180 kDa. Seventy kilodalton did not augment gelatin binding until 2 h, but by 6 h 70 kDa supported more binding than intact fibronectin (P < 0.01). This appeared to result from a cellular response initiated by 70-kDa-gelatin interactions with the macrophages. Within 4 h the majority of gelatin associated with cells under control conditions, and in the presence of fibronectin or 180 kDa, was internalized. Seventy-kilodalton-mediated binding remained localized primarily to the cell surfaces at all times. The macrophages partially degraded the internalized and external gelatin fractions. These results demonstrate that intact fibronectin and specific fibronectin fragments support soluble gelatin interactions with macrophages.