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| 2. |
- Haitina, Tatjana, et al.
(författare)
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Functional characterization of two melanocortin (MC) receptors in lamprey showing orthology to the MC1 and MC4 receptor subtypes
- 2007
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Ingår i: BMC Evolutionary Biology. - : Springer Science and Business Media LLC. - 1471-2148. ; 7, s. 101-
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Tidskriftsartikel (refereegranskat)abstract
- Background The melanocortin (MC) receptors have a key role in regulating body weight and pigmentation. They belong to the rhodopsin family of G protein-coupled receptors (GPCRs). The purpose of this study was to identify ancestral MC receptors in agnathan, river lamprey. Results We report cloning of two MC receptors from river lamprey. The lamprey receptors, designated MCa and MCb, showed orthology to the MC1 and MC4 receptor subtypes, respectively. The molecular clock analysis suggested that lamprey MC receptor genes were not duplicated recently and diverged from each other more than 400 MYR ago. Expression and pharmacological characterization showed that the lamprey MCa receptor was able to bind and be activated by both lamprey and human MSH peptides. The lamprey MCa receptor had relatively high affinity for ACTH derived peptides similarly to the fish MC receptors. We found that both of the lamprey MC receptors were expressed in skin, while the MCb receptor was also found in liver, heart and skeletal muscle. Conclusion This study shows presence of MC receptors in agnathans indicating early signs of specific functions of melanocortin receptor subtypes.
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| 3. |
- Haitina, Tatjana, et al.
(författare)
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Further evidence for ancient role of ACTH peptides at melanocortin (MC) receptors; pharmacology of dogfish and lamprey peptides at dogfish MC receptors
- 2007
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Ingår i: Peptides. - : Elsevier BV. - 0196-9781 .- 1873-5169. ; 28:4, s. 798-805
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Tidskriftsartikel (refereegranskat)abstract
- The cloning of melanocortin (MC) receptors in distant species has provided us tools to get insight in how the ligand–receptors interactions in the MC system have evolved. We have however lacked studies on pharmacology of native ancient melanocortin peptides at the ancient MC receptors. In this paper we synthesized melanocortin peptides from both the sea lamprey (Petromyzon marinus) and spiny dogfish (Squalus acanthias) and tested them on the MC3 and MC4 receptors from spiny dogfish. The results show that both the dogfish and lamprey ACTH peptides have similar or higher affinity than the dogfish α-, β- and γ-MSH peptides to the dogfish MC3 and MC4 receptors. Moreover, both the dogfish and lamprey ACTH peptides have more than 10-fold higher affinity than α-MSH to the dogfish MC4 receptor. We also show that dogfish δ-MSH is able to bind to MC receptors and its potency is higher than of dogfish β-MSH, which is considered to be its precursor. Our results provide the first evidence that native ACTH ligands from dogfish and lamprey have a preference above native MSH peptides to ancient version of the MC3 and MC4 receptors. This further strengthens the hypotheses that the ligand contributing to the first version of the melanocortin ligand-receptor system resembled ACTH.
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| 4. |
- Imai, Koji, et al.
(författare)
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Validation of ozone data from the Superconducting Submillimeter-Wave Limb-Emission Sounder (SMILES)
- 2013
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Ingår i: Journal of Geophysical Research. - : American Geophysical Union (AGU). - 0148-0227 .- 2156-2202 .- 2169-897X. ; 118:11, s. 5750-5769
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Tidskriftsartikel (refereegranskat)abstract
- The Superconducting Submillimeter-Wave Limb-Emission Sounder (SMILES) onboard the International Space Station provided global measurements of ozone profiles in the middle atmosphere from 12 October 2009 to 21 April 2010. We present validation studies of the SMILES version 2.1 ozone product based on coincidence statistics with satellite observations and outputs of chemistry and transport models (CTMs). Comparisons of the stratospheric ozone with correlative data show agreements that are generally within 10%. In the mesosphere, the agreement is also good and better than 30% even at a high altitude of 73km, and the SMILES measurements with their local time coverage also capture the diurnal variability very well. The recommended altitude range for scientific use is from 16 to 73km. We note that the SMILES ozone values for altitude above 26km are smaller than some of the correlative satellite datasets; conversely the SMILES values in the lower stratosphere tend to be larger than correlative data, particularly in the tropics, with less than 8% difference below similar to 24km. The larger values in the lower stratosphere are probably due to departure of retrieval results between two detection bands at altitudes below 28km; it is similar to 3% at 24km and is increasing rapidly down below.
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| 5. |
- Kobayashi, Yuki, et al.
(författare)
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Differential expressions of melanocortin receptor subtypes in melanophores and xanthophores of barfin flounder
- 2010
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Ingår i: General and Comparative Endocrinology. - : Elsevier BV. - 0016-6480 .- 1095-6840. ; 168:1, s. 133-142
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Tidskriftsartikel (refereegranskat)abstract
- alpha-Melanocyte-stimulating hormone (alpha-MSH) is a member of the melanocortin (MC) family, and the MC receptor (MCR) is a member of the G protein-coupled receptor (GPCR) superfamily. We previously found that in barfin flounder, a flatfish, alpha-MSH with an acetyl group at the N-terminus stimulated pigment dispersion in xanthophores; however, this effect was not observed in melanophores. Therefore, the present study was undertaken to find which MCR subtypes are expressed in these pigment cells in order to elucidate how acetylation regulates activities of alpha-MSH-related peptides. Here, we also report the cloning of Mc1r and Mc5r from barfin flounder. Three types of cells-melanophores, xanthophores, and nonchromatophoric dermal cells-were isolated from the skin samples collected from the dorsal fin. These cells were then tested for the expression of Mc1r and Mc5r as well as Mc2r and Mc4r that we had previously cloned. Mc1r and Mc5r transcripts were detected in melanophores, and a sole Mc5r transcript was detected in xanthophores. We had previously found that the efficiency of alpha-MSH was higher than that of desacetyl-alpha-MSH for pigment dispersion in xanthophores. Acetylated MSH peptide may have increased binding affinity to MC5R, whereas alpha-MSH lacks melanin-dispersing activity. Increasing evidences indicate that many GPCRs form heterodimers, and this may affect the affinity of the ligand for the corresponding GPCR. Taken together, the expression of two different Mcr subtypes in melanophores may suggest that a heterodimer consisting of MC1R and MC5R may have a low binding affinity toward alpha-MSH. The present results clarify the types of MCRs that are expressed in melanophores and xanthophores of barfin flounder; furthermore, the results provide important clues about the functional regulation of alpha-MSH-related peptides.
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| 6. |
- Kobayashi, Yuki, et al.
(författare)
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Food deprivation increases the expression of melanocortin-4 receptor in the liver of barfin flounder, Verasper moseri
- 2008
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Ingår i: General and Comparative Endocrinology. - : Elsevier BV. - 0016-6480 .- 1095-6840. ; 155:2, s. 280-287
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Tidskriftsartikel (refereegranskat)abstract
- The melanocortin (MC) system is composed of melanocyte-stimulating hormone, adrenocorticotropic hormone and their receptors. The MC system has a role in both pigmentation and the regulation of energy homeostasis, in which MC4R, one of the five MC receptors, has a key role. Interestingly, the barfin flounder (Pleuronectiformes) reared with a black background shows retarded growth compared to white background-reared fish, which could be associated with the MC system because of its dual role in regulating pigmentation and energy status. Here, we cloned MC4R and assessed the effects of feeding status on its expression in barfin flounder. Barfin flounder MC4R. was composed of 325 amino acids and showed the highest sequence identity to MC4R of fugu (85%), followed by rainbow trout (82%), zebrafish (79%), goldfish (78%), dogfish (71%), chickens (67%), humans (67%) and mice (65%). Among 18 different tissues examined, the predominant expression of MC4R was observed in the brain, liver, testis and ovary as detected with reverse transcription PCR. Food deprivation resulted in a 4-fold increase in the number of MC4R transcripts in the liver, whereas no change was observed in the brain between fasted fish and fed controls. These results suggest that the NIC system including MC4R is associated with energy homeostasis in barfin flounder and that peripheral tissues could play a role in this regulation.
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| 7. |
- Kobayashi, Yuki, et al.
(författare)
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Melanocortin receptor subtypes in interrenal cells and corticotropic activity of α-melanocyte-stimulating hormones in barfin flounder, Verasper moseri
- 2011
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Ingår i: General and Comparative Endocrinology. - : Elsevier BV. - 0016-6480 .- 1095-6840. ; 170:3, s. 558-568
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this study was to characterize the pituitary-interrenal axis in barfin flounder, a flatfish. Adrenocorticotropic hormone (ACTH) and melanocortin 2 receptor (MC2R) have been shown to be indispensable substances in pituitary and interrenal cells for cortisol release, respectively. We previously identified ACTH in the pars distalis of the barfin flounder pituitary gland, and detected transcripts of Mc1r, Mc4r, and Mc5r in the head kidney wherein interrenal cells are located. We have now demonstrated the presence of MC2R, which is a specific receptor for ACTH, in interrenal cells by molecular cloning of Mc2r cDNA and in situ hybridization, and confirmation of the in vitro cortisol-releasing activity of ACTH. These results show the presence of a classical pituitary-interrenal axis in this fish. We also evaluated the role of α-melanocyte-stimulating hormone (α-MSH) and its related peptides. In situ hybridization was used to demonstrate the expression of Mc5r in interrenal cells; both desacetyl-α-MSH and diacetyl-α-MSH showed in vitro cortisol-releasing activities, while the activity of α-MSH was negligible. These findings indicate the presence of an additional pituitary-interrenal axis consisting of α-MSH-like peptides secreted from the neurointermediate lobe of the pituitary and MC5R in the interrenal cells. The cortisol-releasing activity of desacetyl-α-MSH and diacetyl-α-MSH, compared with the low activity of α-MSH, suggest a unique and specific functional role of these forms of MSH peptides. The interrenal co-expression of two subtypes of Mcrs may play a role in this specialization.
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| 8. |
- Takahashi, Akiyoshi, et al.
(författare)
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The melanin-concentrating hormone receptor 2 (MCH-R2) mediates the effect of MCH to control body color for background adaptation in the barfin flounder
- 2007
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Ingår i: General and Comparative Endocrinology. - : Elsevier BV. - 0016-6480 .- 1095-6840. ; 151:2, s. 210-219
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Tidskriftsartikel (refereegranskat)abstract
- Melanin-concentrating hormone (MCH) is a neuropeptide generated in neurons originating in the hypothalamus, from which axons project to the entire brain and neurohypophysis in fish. MCH has both central and peripheral roles such as food intake and body color change. Here we cloned two MCH receptors (MCH-R) from the barfin flounder, Verasper moseri, Pleuronectiformes. The phylogenetic analysis shows that these are orthologues to the mammalian MCH-R1 and MCH-R2 showing 49 and 30% amino acid sequence identity to the corresponding human receptors while they have 31% amino acid sequence identify between them. Essential amino acid residues for ligand binding, signal transduction and receptor conformation, which have been shown in mammalian MCH-R, are well conserved in the flounder MCH-Rs. MCH-R1 has one intron in the extracellular N-terminal region and MCH-R2 has one intron in the DRY motif, which is a homologous position to one of the five introns of human MCH-R2. Orthologues of MCH-R1 and MCH-R2 may have appeared by gene duplication of the ancestry of MCH-Rs having at least two introns, and then MCH-R1 and MCH-R2 inherited different introns in flounder strains. We also determined their tissue distribution and functional role in rearing condition. Reverse transcription PCR revealed that the expression of MCH-R1 is confined to the brain of the barfin flounder, while transcripts of MCH-R2 were detected in the brain, pituitary, eyeball, gill, atrium, ventricle, head kidney, body kidney, spleen, intestine, inclinator, skeletal muscle testis, ovary, eyed-side skin, and non-eyed-side skin. The expression of MCH-R2 in eyed-side skin was higher in fish reared in a black tank (121 days) than in a white tank while the expression levels of MCH in the brain were significantly greater in the group reared with the white background suggesting down-regulation of this receptor gene with increased levels of MCH. The results suggest that the MCH-R2 mediates the effect of MCH to control body color for background adaptation in the eyed-side skin of the barfin flounder.
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