Transglutaminase-mediated polyamination of vasoactive intestinal peptide (VIP) Gln16 residue modulates VIP/PACAP receptor activity.
Previous data showing an increase of receptor binding activity of [R16]VIP, a vasoactive intestinal peptide (VIP) structural analogue containing arginine at the position 16 of its amino acid sequence, have pointed out the importance of a positive charge at this site. Here, the functional characterization of three VIP polyaminated adducts (VIPDap, VIPSpd, and VIPSpm), obtained by a transglutaminase-catalysed reaction between the VIP Gln16 residue and 1,3-diaminopropane (Dap), spermidine (Spd), or spermine (Spm), is reported. Appropriate binding assays and adenylate cyclase enzymatic determinations have shown that these VIP adducts act as structural VIP agonists, both in vitro and in vivo. In particular, their IC50 and EC50 values of human and rat VIP/pituitary adenylate cyclase activating peptide (PACAP)1 and VIP/PACAP2 receptors indicate that VIPDap is a VIP agonist, with an affinity and a potency higher than that of VIP, while VIPSpd and VIPSpm are also agonists but with affinities lower than that of VIP. These findings suggest that the difference in adduct agonist activity reflects the differences in the positive charge and carbon chain length of the polyamine covalently linked with the VIP Gln16 residue. In addition, the data obtained strongly suggest that the length of polyamine carbon chain could be critical for the interaction of the agonist with its receptor, even though possible hydrophobic interaction cannot be ruled out. In vivo experiments on murine J774 macrophage cell cultures have shown the ability of these compounds to stimulate the inducible nitric oxide synthase activity at the transcriptional level.
De Maria
Salvatore
S
Department of Experimental Medicine and Centro di Ricerca Interdipartimentale di Scienze Computazionali e Biotecnologiche, II University of Naples, Italy.
Metafora
Salvatore
S
Metafora
Vittoria
V
Morelli
Francesco
F
Robberecht
Patrick
P
Waelbroeck
Magalì
M
Stiuso
Paola
P
De Rosa
Alfredo
A
Cozzolino
Anna
A
Esposito
Carla
C
Facchiano
Angelo
A
Cartenì
Maria
M
D000595:Amino Acid Sequence; D000818:Animals; D002478:Cells, Cultured; D006224:Cricetinae; D005973:Glutamine / Q000737:chemistry*; D006801:Humans; D008264:Macrophages / Q000166:cytology / Q000187:drug effects; D051379:Mice; D008969:Molecular Sequence Data; D009569:Nitric Oxide / Q000378:metabolism; D019001:Nitric Oxide Synthase / Q000187:drug effects / Q000235:genetics; D052247:Nitric Oxide Synthase Type II; D011073:Polyamines / Q000737:chemistry; D051381:Rats; D051236:Receptors, Pituitary Adenylate Cyclase-Activating Polypeptide; D011979:Receptors, Pituitary Hormone / Q000378:metabolism*; D018005:Receptors, Vasoactive Intestinal Peptide / Q000187:drug effects / Q000378:metabolism*; D051239:Receptors, Vasoactive Intestinal Peptide, Type II; D051238:Receptors, Vasoactive Intestinal Polypeptide, Type I; D013095:Spermidine / Q000737:chemistry; D013096:Spermine / Q000737:chemistry; D011503:Transglutaminases / Q000737:chemistry / Q000378:metabolism*; D014660:Vasoactive Intestinal Peptide / Q000737:chemistry* / Q000378:metabolism* / Q000494:pharmacology
D011073:Polyamines; D051236:Receptors, Pituitary Adenylate Cyclase-Activating Polypeptide; D011979:Receptors, Pituitary Hormone; D018005:Receptors, Vasoactive Intestinal Peptide; D051239:Receptors, Vasoactive Intestinal Peptide, Type II; D051238:Receptors, Vasoactive Intestinal Polypeptide, Type I; D005973:Glutamine; D013096:Spermine; D009569:Nitric Oxide; D014660:Vasoactive Intestinal Peptide; C496319:NOS2 protein, human; D019001:Nitric Oxide Synthase; D052247:Nitric Oxide Synthase Type II; C496317:Nos2 protein, mouse; C496318:Nos2 protein, rat; D011503:Transglutaminases; D013095:Spermidine