[3H]Fucose incorporation by healing skin wounds and the effect of transglutaminase inhibitors

Glycoprotein composition in cyclophosphamide-induced lung fibrosis

The present study investigated the glycosylation state of proteins in lung tissue of a cyclophosphamide-induced model of pulmonary fibrosis in rats. In fibrotic lung, the carbohydrate constituents (total hexose, fucose, sialic acid and hexosamine) of salt-soluble, collagenase, elastase and papain digested glycoproteins were significantly higher compared to normal lungs. Interestingly, fibrotic lung tissues had higher activities of mannosyl, glucosyl, galactosyl, sialyl and fucosyl transferases than normal lung tissues. Similarly, mannosyl, glucosyl, galactosyl, sialyl and fucosyl transferases were higher in serum from rats with fibrosis than in that from normals. These data indicate that glycoprotein metabolism is significantly altered from normal in animals with interstitial lung fibrosis.

Increase in transglutaminase and its extracellular products in response to an inflammatory stimulus by lipopolysaccharide

Transglutaminase (TGase) activities were measured in rat tissues 1-7 days after intraperitoneal injection of saline or lipopolysaccharide (LPS) and in the cells and media from pre-confluent human fibroblasts cultured for two days in the presence or absence of LPS. epsilon (gamma-Glutamyl)lysine and [3H]putrescine-labelled gamma-glutamyl derivatives in extracellular and cellular fibroblast proteins were also measured. Three effects of LPS were observed. Firstly, total TGase activity is greater in the tissues from the LPS-injected animals, with the maximum increase occurring at 1 day in dermis, epidermis and liver, at 5 days in the aorta and, after a decrease at 2-5 days, at 7 days in the panniculus muscle. Secondly, the fraction of the total activity which is buffer-extractable is greater on days 1 and/or 2 in all the tissues from the LPS-injected rats. Thirdly, in cultures of human fibroblasts, LPS increases that fraction of bound [3H]putrescine and of TGase and its gamma-glutamylamine products which occurs in the extracellular medium. In addition, a higher concentration of TGase-derived crosslinks was found in extracellular as opposed to intracellular proteins. In conjunction with previous findings in skin wound healing and in atherosclerosis these results support the concept of an extracellular function for tissue TGase and indicate that there is a widespread association of increases in TGase and its extracellular products with inflammation and the healing or fibrotic processes which follow it.

Biocompatibility of wound management products: the effect of various monosaccharides on L929 and 2002 fibroblast cells in culture

The effects of various monosaccharides on the growth of human 2002 and mouse L929 fibroblast cultures have been investigated. Eleven monosaccharides having acidic, neutral, and basic characteristics were evaluated in a bioassay procedure developed for the investigation of biocompatibility of wound management materials. Rate of growth in both cell lines was inhibited by D-galacturonic acid and by D-glucuronic acid. Although most neutral sugars produced no significant change in the growth rate or in the morphology of the cells, galactose produced a significant increase in the growth rate of both cell lines whilst L-fucose caused a significant decrease in growth of the L929 cells but did not significantly affect the growth of 2002 cells; xylose increased the growth rate of L929 but not 2002 cells. D-Glucosamine, a basic sugar, produced inhibition of growth which followed a different pattern from that produced by the acidic sugars; N-acetylglucosamine produced a species specific increase in cell growth of L929 cells. The results show that the effects produced by the monosaccharides on the cultured fibroblasts are related to their chemical structure and to cell line, and suggest that the use of galactose as a possible aid to wound healing should be investigated.

Components of increased labelling with putrescine and fucose during healing of skin wounds

To study the glycoproteins and transglutaminase substrates involved in healing, wounds were made in the skin of anesthetized rats with a biopsy punch. Explants made 1-5 days later were incubated with [3H]-labelled putrescine, fucose or proline. As compared with unwounded skin there was an increased incorporation of label which was greatest at 3 days. Incubation for various times suggests that the incorporation of fucose and proline is dependent on protein synthesis, whereas putrescine is incorporated into preformed proteins. Putrescine and fucose label polypeptides with an Mr of about 45,000 before and 14,000 after reduction. These correspond in size with the aminopropeptide of type III collagen. Other labelled material of higher molecular weight is partly degraded to similar polypeptides on collagenase digestion. Much of the [3H]putrescine in the polypeptides is in the form of gamma-glutamyl putrescine. It is hypothesized that isopeptide linkage of the aminopropeptide III occurs in wound healing.