A peptide of the α3 chain of type IV collagen protects basement membrane against damage by PMN

We have shown that basement membrane (BM) collagen (type IV), and specifically the peptide CNYYSNSYSFWLASLNPER (a.a. 185-203), from the non-collagenous domain of the alpha 3 chain inhibits PMN. We examined the role of this peptide on PMN damage to BM in a vessel wall model. The presence of the endothelial monolayer as well as treatment of PMN with the alpha 3(IV) 185-203 peptide reduced damage to BM by non-activated but not by activated PMN. The damage inhibition is unique to the alpha 3(IV) peptide and not exhibited by comparable alpha 1(IV) and alpha 2(IV) chain peptides. A shorter peptide alpha 3(IV) 185-191, containing the -SNS- triplet, reduced damage, whereas the one lacking the triplet, residues 194-203, was not effective. The CD47-alpha v beta 3 integrin complex is the receptor for the alpha 3(IV) peptide. Incubation of PMN with CD47 reactive mAb followed by the alpha 3(IV) peptide abolished its protective effect on BM damage. (C) 1999 Academic Press.