Showing papers by "Tetsuya Ohtaki published in 2001"

Metastasis suppressor gene KiSS-1 encodes peptide ligand of a G-protein-coupled receptor.

Abstract: Metastasis is a major cause of death in cancer patients and involves a multistep process including detachment of cancer cells from a primary cancer, invasion of surrounding tissue, spread through circulation, re-invasion and proliferation in distant organs. KiSS-1 is a human metastasis suppressor gene1, that suppresses metastases of human melanomas2 and breast carcinomas3 without affecting tumorigenicity. However, its gene product and functional mechanisms have not been elucidated. Here we show that KiSS-1 (refs 1, 4) encodes a carboxy-terminally amidated peptide with 54 amino-acid residues, which we have isolated from human placenta as the endogenous ligand of an orphan G-protein-coupled receptor (hOT7T175) and have named ‘metastin’. Metastin inhibits chemotaxis and invasion of hOT7T175-transfected CHO cells in vitro and attenuates pulmonary metastasis of hOT7T175-transfected B16-BL6 melanomas in vivo. The results suggest possible mechanisms of action for KiSS-1 and a potential new therapeutic approach.

Conformation of a peptide ligand bound to its G-protein coupled receptor.

Abstract: Many peptide hormones elicit a wide array of physiological effects by binding to G-protein coupled receptors. We have determined the conformation of pituitary adenylate cyclase activating polypeptide, PACAP(1–21)NH2, bound to a PACAP-specific receptor by NMR spectroscopy. Residues 3–7 form a unique β-coil structure that is preceded by an N-terminal extended tail. This β-coil creates a patch of hydrophobic residues that is important for receptor binding. In contrast, the C-terminal region (residues 8–21) forms an α-helix, similar to that in the micelle-bound PACAP. Thus, the conformational difference between PACAP in the receptor-bound and the micelle-bound states is limited to the N-terminal seven residues. This observation is consistent with the two-step ligand transportation model in which PACAP first binds to the membrane nonspecifically and then diffuses two-dimensionally in search of its receptor; a conformational change at the N-terminal region then allows specific interactions between the ligand and the receptor.

Distribution of galanin-like peptide in the rat brain.

Abstract: Galanin-like peptide (GALP) is a novel galanin-like peptide isolated from the porcine hypothalamus. To determine the distribution of GALP in the rat brain, we performed immunohistochemical studies using a monoclonal antibody toward the N-terminal sequence of GALP. GALP-immunoreactive neuronal cell bodies were observed only in the arcuate nucleus (Arc), which was further confirmed by in situ hybridization studies using digoxigenin-labeled antisense GALP riboprobe. Additional immunostained cells were found in the median eminence and infundibular stalk. The GALP neurons found in the Arc were further characterized by double label immunohistochemistry. More than 85% of the GALP neurons were immunostained with leptin receptor antibody. However, the GALP neurons and fibers found in the Arc were not labeled with alpha-MSH, somatostatin, neuropeptide Y, agouti-related protein, or galanin antibodies, indicating that GALP is found in neurons other than these known Arc neurons. Dense staining of GALP-containing fibers was found in the anterior parvicellular part of the paraventricular hypothalamic nucleus, in the ventral part of the lateral septal nucleus, and in the bed nucleus of the stria terminalis. Relatively dense staining was noted in the medial preoptic area (MPA), and weak staining was noted in the periventricular hypothalamic nucleus. Detailed double labeling studies in the paraventricular hypothalamic nucleus demonstrated that GALP-containing fibers converged in a more rostral direction than did agouti-related protein-containing fibers. Furthermore, GALP-immunoreactive fibers were in close apposition with GnRH-immunoreactive fibers in the MPA and bed nucleus of the stria terminalis, and about 6% of GnRH-positive neurons in the MPA showed close contact with the GALP-immunoreactive fibers. Our findings indicate that GALP neurons, as leptin-responsive neurons, may participate in the regulation of feeding behavior and/or reproductive functions.

Stimulation effect of galanin-like peptide (GALP) on luteinizing hormone-releasing hormone-mediated luteinizing hormone (LH) secretion in male rats.

Abstract: Galanin-like peptide (GALP) is a recently isolated hypothalamic peptide which has sequence homology to galanin and binds to galanin receptors with high affinity. It has been shown that GALP neurons are localized in the arcuate nucleus and that GALP-immunoreactive fibers are in close apposition with LHRH neurons in the medial preoptic area (MPA). In the present study, we found that intracerebroventricular (icv) administration of GALP increased the plasma LH level but did not change the levels of other hormones. Concomitantly, accumulation of c-Fos protein was dramatically increased in the nuclei of LHRH-positive cells in the MPA by icv GALP administration. Furthermore, the GALP-induced plasma LH response was completely abolished by pretreatment with Cetrorelix, a LHRH receptor antagonist. On the other hand, GALP did not affect the release of LH, FSH, TSH, ACTH, GH or PRL directly from dispersed rat pituitary cells in vitro. These results strongly suggest a role for GALP in the control of gonadotropin secre...

Novel physiologically active peptide and use thereof

Abstract: The present invention intends to provide a novel peptide and use thereof. More particularly, the present invention provides a novel peptide and a DNA encoding the same, a drug comprising the peptide or DNA, a screening method/screening kit for a compound or its salt that promotes or inhibits the activity of the peptide, a compound or its salt obtained by the screening, a drug comprising the compound or its salt, etc. The peptide of the invention and the DNA encoding the same are usable, e.g., for the diagnosis, treatment, prevention, etc. of digestive diseases, etc. Moreover, the peptide of the invention is useful as a reagent for screening a compound or its salt that promotes or inhibits the activity of the protein of the invention.

Novel protein, dna thereof and process for producing the same

Abstract: A novel protein containing a peptide having a ligand activity to a G protein-coupled receptor protein; amides, esters, salts, etc. of the peptide; and drugs, etc. containing the same.

Bio-organic synthesis of a newly isolated peptide metastin, metastasis suppressor gene KiSS-1 processing product

Abstract: Metastin, a newly isolated peptide ligand of orphan receptor hOT7T175, was synthesized by a bio-organic technique combining recombinant DNA technology with a cysteine-specific cleavage reaction.

Nouvelle proteine, adn codant pour celle-ci, et son procede de production

Abstract: La presente invention concerne une nouvelle proteine contenant un peptide ayant une activite de ligand envers une proteine a recepteur couple a la proteine G, ainsi que des amides, esters, sels, etc. du peptide, et que des produits pharmaceutiques, etc. les contenant.

An alternative approach to the synthesis of a recombinant galanin-like peptide (GALP)

Abstract: GALP is a novel galanin-like peptide that has been isolated from porcine hypothalamus in our Research Division. In the present study, a large quantity of porcine GALP (pGALP) was synthesized with a high degree of purity using recombinant DNA technology. A basic fibroblast growth factor (bFGF) mutein, CS23, was used as a fusion partner and pGALP was released by chemical cleavage with cyanogen bromide (BrCN). Using various criteria such as HPLC, SDS–PAGE, amino acid analysis, amino acid sequence, relative-molecular-mass measurement by liquid secondary-ion mass spectrometry, as well as biological activity, the purified molecule was shown to be pGALP and was found to have the same biological activity as a chemically synthesized standard. The pGALP obtained here will be useful for elucidation of its physiological role in vivo. Furthermore, CS23ML76, a newly prepared bFGF mutein, was found to be more appropriate than CS23 as a fusion partner in this procedure.

Nouveau peptide actif sur le plan physiologique et utilisation associee

Abstract: L'invention concerne un nouveau peptide ainsi que l'utilisation de celui-ci, et elle concerne notamment un nouveau peptide, un ADN codant ce peptide, des medicaments contenant ce peptide ou cet ADN, un procede/necessaire de criblage destine a un compose ou a un sel de celui-ci favorisant ou inhibant l'activite du peptide ci-dessus, des composes ou sels de ce peptide obtenus au moyen du criblage, ainsi que des medicaments contenant les composes ou sels de ce peptide. Il est possible d'utiliser le peptide ci-dessus decrit ainsi que l'ADN codant pour celui-ci, par exemple dans le diagnostic, le traitement et la prevention de maladies digestives. En outre, ce peptide est utile en tant que reactif dans le criblage d'un compose ou d'un sel de celui-ci favorisant ou inhibant l'activite du peptide ci-dessus.