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

Abstract

Punch wounds (3 mm) were made in the skin of rats and the animals were killed after 1 or 3 days. Plugs (4 mm) of wounded and unwounded skin were incubated in vitro with [3H]fucose. The labelled plugs were homogenized and subjected to sequential extraction with buffered salt solutions, ethanol–ether, and 8 M urea – 50 mM dithiothreitol (DTT). Nondialysable counts in the extracts and insoluble residue were determined and the incorporation of label by wounded and unwounded skin plugs was compared. Wound plugs showed a greater total incorporation of [3H]fucose. In addition, a greater proportion of [3H]fucose was found in the urea–DTT extracts. The highest specific activity (disintegrations per minute t [3H]fucose per milligram dry weight) was found in a finely dispersed precipitate, sedimenting at 10 000 × g but not at 1000 × g. The transglutaminase inhibitors aminoacetonitrile and dansyl cadaverine were found to increase the extractability of a portion of the material which incorporated [3H]fucose without affecting the total incorporation. These results show that healing wounds have an increased biosynthetic capacity for an insoluble fucosylated glycoprotein fraction and they suggest that transglutaminase is necessary to make this fraction fully insoluble.