Inhibition of NF-kappaB activity by plasmid expressed alphaMSH peptide.

Alpha-Melanocyte Stimulating Hormone (alphaMSH) is a neuroimmunomodulatory peptide with remarkable anti-inflammatory properties. Daily or twice daily administration of the peptide reduces the symptoms of several inflammatory animal disease models and the peptide has demonstrated safety in human trials. Unfortunately, the pharmacokinetics of peptide delivery are not favorable from the pharmaceutical perspective. For this reason, plasmid-based vectors were created that constitutively express the immunomodulatory peptide. The fusion constructs encode the 13 amino acids of alphaMSH in frame with the first domain of serum albumin, separated by a linker and furin cleavage sites. The fusion proteins were expressed and processed in human fetal kidney (293) cells. Supernatant from B16/F10 cells transfected with the constructs stimulated secretion of melanin from melanocytes. Furthermore, transfected cytoskeletal muscle (Sol8) cells secreted bioactive alphaMSH that reduced NF-kappaB-mediated transcriptional activation of a luciferase reporter gene. The activity of these vectors provides tools and the impetus for testing the constructs in several animal models of chronic inflammation.