vasoactive-intestinal-peptide and vasoactive-intestinal-peptide-(1-12)

It is well known that psoriasis, an immunogenetic cutaneous disorder whose major pathogenic findings are epidermal hyperplasia and T-cell infiltration, is aggravated by psychological stresses. Although the exact mechanism is not yet clarified, antidromic secretion of neuropeptides by cutaneous nerve fibers is thought to be involved. In this study, we examined the effect and mechanism of vasoactive intestinal polypeptide (VIP), one of the major neuropeptides, on the proliferation of HaCaT cell which is a spontaneous, immortalized, human keratinocyte cell line. Twenty-four and 48 h after its addition, 1 pM to 100 nM of VIP increased the number of cells cultured with/without serum. We indirectly verified VIP(1)R on the surface of HaCaT cell based on the proliferative ability of various VIP families such as VIP, PACAP and secretin, and increased PKA level 30 min after stimulation. However, because H-89, a PKA inhibitor, did not inhibit the proliferative potential of VIP, its mitogenicity is not medicated through VIP(1)R. One nM VIP produced the TGF-alpha protein which is a strong mitogen of keratinocytes and increased in the psoriatic lesion 2.25 times more compared with the control. Genistein, a tyrosine kinase inhibitor, abrogated the mitogenic activity of VIP. Like VIP, VIP fragments, VIP(1-12) and VIP(10-28) also acted as a mitogen for HaCaT cells through the same mechanism. Collectively, our studies clearly show that VIP and its fragments stimulate keratinocyte growth, not through increased cAMP level, but through increased TGF-alpha protein production.

Topics: Cell Division; Cell Line; Cyclic AMP; Cyclic AMP-Dependent Protein Kinases; DNA; Enzyme Inhibitors; Hormone Antagonists; Humans; Isoquinolines; Keratinocytes; Mitogens; Neuropeptides; Peptide Fragments; Pituitary Adenylate Cyclase-Activating Polypeptide; Receptors, Cell Surface; Receptors, Vasoactive Intestinal Peptide; Receptors, Vasoactive Intestinal Polypeptide, Type I; Secretin; Sermorelin; Signal Transduction; Stress, Physiological; Sulfonamides; Transforming Growth Factor alpha; Vasoactive Intestinal Peptide

The purpose of this study was to begin to determine the mechanisms underlying vasodilation elicited by vasoactive intestinal peptide (VIP) in sterically stabilized liposomes (SSL) in the in situ peripheral microcirculation. Using intravital microscopy, we found that suffusion of VIP in SSL (0.42 and 0.85 nmol) onto the hamster cheek pouch for 1 h elicited significant and prolonged concentration-dependent vasodilation (P < 0.05). Suffusion of VIP in SSL (0.1 nmol) for 7 min elicited a qualitatively similar response, although its magnitude was significantly smaller than that elicited by 1 h of suffusion of VIP in SSL (P < 0.05). The VIP-receptor antagonist VIP-(10-28), but not the amino-terminal fragment VIP-(1-12), significantly attenuated and delayed the onset of VIP in SSL-induced vasodilation (P < 0.05). The nitric oxide (NO) synthase inhibitor NG-nitro-L-arginine methyl ester (L-NAME), but not NG-nitro-D-arginine methyl ester (D-NAME), abrogated VIP in SSL-induced responses. We conclude that VIP in SSL elicits significant and prolonged vasodilation in the in situ peripheral microcirculation, which is specific, partly receptor dependent, and partly transduced by the L-arginine/NO biosynthetic pathway.

Topics: Animals; Arterioles; Cheek; Cricetinae; Dose-Response Relationship, Drug; Drug Carriers; Humans; Liposomes; Male; Mesocricetus; Microcirculation; Peptide Fragments; Phosphatidylcholines; Phosphatidylglycerols; Time Factors; Vasoactive Intestinal Peptide; Vasodilation

Intracerebroventricular administration of vasoactive intestinal peptide (VIP) disturbed the learning by rats of the location of a platform submerged in a water pool. When the platform was removed from the pool, VIP injection produced marked impairment of the ability to find a previously learned location in the pool. This spatial memory impairment caused by VIP was restored by peripheral pre-administration of cerulein.

Topics: Animals; Ceruletide; Injections, Intraventricular; Learning; Male; Peptide Fragments; Rats; Rats, Wistar; Space Perception; Vasoactive Intestinal Peptide

The low-energy collision-induced dissociation reactions of a series of multiply-protonated peptides have been investigated by tandem mass spectrometry. It is known that doubly-protonated tryptic peptides undergo facile fragmentation yielding redundant sequence information. The present work has shown that this fortunate circumstance seems likely to be the exception rather than the rule. The presence of additional basic residues, at positions other than the C-terminus, complicates the spectra. The most important such complication discovered in the present work involves wholesale transfer of one or two residues from the C-terminal end of a doubly-charged b fragment to the side chain of a lysine residue located near the N-terminus, resulting in mass shifts of the products of subsequent second-stage fragmentations. Other examples of the participation of the flexible lysine side chain are suggested but could not be confirmed to the same extent. The role of Coulombic repulsion in facilitating fragmentation has been explored via investigations of triply- and quadruply-protonated basic peptides bearing one charge for every three or four amino acid residues. Such species yielded almost no sequence information under low-energy collision conditions, due to the localization of the ionizing protons on highly basic sites rather than on the peptide backbone. It is proposed that collisionally activated mobilization of protons from the basic sites, where they are originally located upon formation, to the backbone is a necessary condition for structurally useful fragmentation to occur. It was not possible, on the basis of the present work, to deduce mechanistic generalizations and predictive schemes which would permit structural interpretations of such fragment spectra for unknown peptides.

Topics: Amino Acid Sequence; Angiotensin I; Bradykinin; Endorphins; gamma-Endorphin; Mass Spectrometry; Molecular Sequence Data; Peptide Fragments; Peptides; Protons; Sequence Analysis; Substance P; Vasoactive Intestinal Peptide

Topics: Acquired Immunodeficiency Syndrome; Amino Acid Sequence; Antigens, Differentiation, T-Lymphocyte; Chemotaxis, Leukocyte; HIV; HIV Envelope Protein gp120; Humans; Molecular Sequence Data; N-Formylmethionine Leucyl-Phenylalanine; Peptide Fragments; Receptors, HIV; Receptors, Virus; Retroviridae Proteins; Sequence Homology, Nucleic Acid; T-Lymphocytes; Vasoactive Intestinal Peptide