Cyclosporin H is a natural cyclic undecapeptide that selectively antagonizes the formyl peptide receptor at concentrations ranging from 0.1 to 10 μM. Unlike cyclosporin A , cyclosporin H does not bind cyclophilin to evoke an immunosuppressant response. Cyclosporin H has been reported to inhibit phorbol ester-mediated effects in mouse skin and block calcium/calmodulin-dependent EF-2 phosphorylation in vitro.
Cyclosporin H is a minor analogue of the cyclosporin family which is immunologically inactive as it does not bind to immunophilin. Cyclopsorin H is the most extensively investigated of the minor cyclosporin analogues and displays a range of activities. It is a potent inhibitor of tumour-promoting phorbol esters on mouse skin in vivo, and of calcium/calmodulin-dependent EF-2 phosphorylation in vitro, a potent and selective antagonist of formyl peptide receptor and inhibitor of formyl peptide-induced superoxide formation.
Cyclosporin H is a selective inhibitor of formyl peptide receptor-1 (FPR-1) and formyl peptide-induced superoxide formation in neutrophils. Cyclosporin H does not bind cyclophilin or evoke an immunosuppressant response. Cyclosporin H has been reported to inhibit tumor promoting phorbol ester TPA/PMA in mouse skin cells and to inhibit calcium/calmodulin-dependent EF-2 phosphorylation.
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