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Palominos MF, Muhl V, Richards EJ, Miller CT, Martin CH. Jaw size variation is associated with a novel craniofacial function for galanin receptor 2 in an adaptive radiation of pupfishes. Proc Biol Sci 2023; 290:20231686. [PMID: 37876194 PMCID: PMC10598438 DOI: 10.1098/rspb.2023.1686] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2023] [Accepted: 10/02/2023] [Indexed: 10/26/2023] Open
Abstract
Understanding the genetic basis of novel adaptations in new species is a fundamental question in biology. Here we demonstrate a new role for galr2 in vertebrate craniofacial development using an adaptive radiation of trophic specialist pupfishes endemic to San Salvador Island, Bahamas. We confirmed the loss of a putative Sry transcription factor binding site upstream of galr2 in scale-eating pupfish and found significant spatial differences in galr2 expression among pupfish species in Meckel's cartilage using in situ hybridization chain reaction (HCR). We then experimentally demonstrated a novel role for Galr2 in craniofacial development by exposing embryos to Garl2-inhibiting drugs. Galr2-inhibition reduced Meckel's cartilage length and increased chondrocyte density in both trophic specialists but not in the generalist genetic background. We propose a mechanism for jaw elongation in scale-eaters based on the reduced expression of galr2 due to the loss of a putative Sry binding site. Fewer Galr2 receptors in the scale-eater Meckel's cartilage may result in their enlarged jaw lengths as adults by limiting opportunities for a circulating Galr2 agonist to bind to these receptors during development. Our findings illustrate the growing utility of linking candidate adaptive SNPs in non-model systems with highly divergent phenotypes to novel vertebrate gene functions.
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Affiliation(s)
- M. Fernanda Palominos
- Department of Integrative Biology, University of California, 3101 Valley Life Sciences Building, Berkeley, CA 94720, USA
- Museum of Vertebrate Zoology, University of California, Berkeley, CA 94720, USA
| | - Vanessa Muhl
- Department of Integrative Biology, University of California, 3101 Valley Life Sciences Building, Berkeley, CA 94720, USA
- Museum of Vertebrate Zoology, University of California, Berkeley, CA 94720, USA
| | - Emilie J. Richards
- Department of Ecology, Evolution, and Behavior, University of Minnesota, Minneapolis, MN, USA
| | - Craig T. Miller
- Department of Molecular & Cell Biology, University of California, Berkeley, CA, USA
| | - Christopher H. Martin
- Department of Integrative Biology, University of California, 3101 Valley Life Sciences Building, Berkeley, CA 94720, USA
- Museum of Vertebrate Zoology, University of California, Berkeley, CA 94720, USA
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2
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Gao X, Wang X, Wang X, Li H, Xu L, Fang Y, Cao S, Huang B, Chen H, Xing R, Liu B. Effect of winter feeding frequency on growth performance, biochemical blood parameters, oxidative stress, and appetite-related genes in Takifugu rubripes. FISH PHYSIOLOGY AND BIOCHEMISTRY 2022; 48:1167-1181. [PMID: 35941472 DOI: 10.1007/s10695-022-01107-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/14/2022] [Accepted: 07/31/2022] [Indexed: 06/15/2023]
Abstract
Tiger pufferfish (Takifugu rubripes) is one of Asia's most economically valuable aquaculture species. However, winter production of this species in North China is limited by low water temperature and unavailability of high-quality feed, resulting in high mortality and low profitability. Therefore, the aim of this study was to evaluate the effect of feeding frequency (F1: one daily meal; F2: two daily meals; F3: four daily meals; F4: continuous diurnal feeding using a belt feeder) on the growth performance, plasma biochemistry, digestive and antioxidant enzyme activities, and expression of appetite-related genes in T. rubripes (initial weight: 266.80 ± 12.32 g) cultured during winter (18.0 ± 1.0 °C) for 60 days. The results showed that fish in the F3 group had the highest final weight, weight gain rate, specific growth rate, survival rate, and best feed conversion ratio. Additionally, daily feed intake increased significantly with increasing feeding frequency. The protein efficiency and lipid efficiency ratios of fish in the F3 group were significantly higher than those of fish in the other groups. Furthermore, total cholesterol, triglycerides, and glucose levels increased with increasing feeding frequency, peaking in the F2 group and decreasing under higher feeding frequencies. The antioxidant (superoxide dismutase, catalase, glutathione, and glutathione peroxidase) and digestive (trypsin, amylase, and lipase) enzyme activities of fish in the F1 group were significantly higher than those of fish in the F3 and F4 groups. Additionally, there was a decrease in orexin expression with increasing feeding frequency. In contrast, the expression levels of tachykinin, cholecystokinin, and leptin increased with increasing feeding frequency, peaking in the F4 group. Overall, the findings of this study indicated that a feeding frequency of four meals per day was optimal for improved growth performance of pufferfish juveniles cultured during winter.
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Affiliation(s)
- Xiaoqiang Gao
- Key Laboratory for Sustainable Development of Marine Fisheries, Ministry of Agriculture, Qingdao Key Laboratory for Marine Fish Breeding and Biotechnology, Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao, 266071, People's Republic of China
| | - Xinyi Wang
- Key Laboratory for Sustainable Development of Marine Fisheries, Ministry of Agriculture, Qingdao Key Laboratory for Marine Fish Breeding and Biotechnology, Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao, 266071, People's Republic of China
- College of Fisheries and Life Science, Ocean University, Shanghai, 201306, People's Republic of China
| | - Xi Wang
- Key Laboratory for Sustainable Development of Marine Fisheries, Ministry of Agriculture, Qingdao Key Laboratory for Marine Fish Breeding and Biotechnology, Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao, 266071, People's Republic of China
- College of Fisheries and Life Science, Ocean University, Shanghai, 201306, People's Republic of China
| | - Hongxu Li
- Key Laboratory for Sustainable Development of Marine Fisheries, Ministry of Agriculture, Qingdao Key Laboratory for Marine Fish Breeding and Biotechnology, Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao, 266071, People's Republic of China
| | - Liang Xu
- Key Laboratory for Sustainable Development of Marine Fisheries, Ministry of Agriculture, Qingdao Key Laboratory for Marine Fish Breeding and Biotechnology, Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao, 266071, People's Republic of China
| | - Yingying Fang
- Key Laboratory for Sustainable Development of Marine Fisheries, Ministry of Agriculture, Qingdao Key Laboratory for Marine Fish Breeding and Biotechnology, Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao, 266071, People's Republic of China
| | - Shuquan Cao
- Key Laboratory for Sustainable Development of Marine Fisheries, Ministry of Agriculture, Qingdao Key Laboratory for Marine Fish Breeding and Biotechnology, Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao, 266071, People's Republic of China
| | - Bin Huang
- Key Laboratory for Sustainable Development of Marine Fisheries, Ministry of Agriculture, Qingdao Key Laboratory for Marine Fish Breeding and Biotechnology, Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao, 266071, People's Republic of China
| | - Haibin Chen
- Yuhai Hongqi Ocean Engineering Co. LTD, Rizhao, 276800, People's Republic of China
| | - Rui Xing
- Yuhai Hongqi Ocean Engineering Co. LTD, Rizhao, 276800, People's Republic of China
| | - Baoliang Liu
- Key Laboratory for Sustainable Development of Marine Fisheries, Ministry of Agriculture, Qingdao Key Laboratory for Marine Fish Breeding and Biotechnology, Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao, 266071, People's Republic of China.
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3
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Appetite regulating genes in zebrafish gut; a gene expression study. PLoS One 2022; 17:e0255201. [PMID: 35853004 PMCID: PMC9295983 DOI: 10.1371/journal.pone.0255201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2021] [Accepted: 05/16/2022] [Indexed: 11/19/2022] Open
Abstract
The underlying molecular pathophysiology of feeding disorders, particularly in peripheral organs, is still largely unknown. A range of molecular factors encoded by appetite-regulating genes are already described to control feeding behaviour in the brain. However, the important role of the gastrointestinal tract in the regulation of appetite and feeding in connection to the brain has gained more attention in the recent years. An example of such inter-organ connection can be the signals mediated by leptin, a key regulator of body weight, food intake and metabolism, with conserved anorexigenic effects in vertebrates. Leptin signals functions through its receptor (lepr) in multiple organs, including the brain and the gastrointestinal tract. So far, the regulatory connections between leptin signal and other appetite-regulating genes remain unclear, particularly in the gastrointestinal system. In this study, we used a zebrafish mutant with impaired function of leptin receptor to explore gut expression patterns of appetite-regulating genes, under different feeding conditions (normal feeding, 7-day fasting, 2 and 6-hours refeeding). We provide evidence that most appetite-regulating genes are expressed in the zebrafish gut. On one hand, we did not observed significant differences in the expression of orexigenic genes (except for hcrt) after changes in the feeding condition. On the other hand, we found 8 anorexigenic genes in wild-types (cart2, cart3, dbi, oxt, nmu, nucb2a, pacap and pomc), as well as 4 genes in lepr mutants (cart3, kiss1, kiss1r and nucb2a), to be differentially expressed in the zebrafish gut after changes in feeding conditions. Most of these genes also showed significant differences in their expression between wild-type and lepr mutant. Finally, we observed that impaired leptin signalling influences potential regulatory connections between anorexigenic genes in zebrafish gut. Altogether, these transcriptional changes propose a potential role of leptin signal in the regulation of feeding through changes in expression of certain anorexigenic genes in the gastrointestinal tract of zebrafish.
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4
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Ishikawa A, Yamanouchi S, Iwasaki W, Kitano J. Convergent copy number increase of genes associated with freshwater colonization in fishes. Philos Trans R Soc Lond B Biol Sci 2022; 377:20200509. [PMID: 35634928 PMCID: PMC9149799 DOI: 10.1098/rstb.2020.0509] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2021] [Accepted: 03/14/2022] [Indexed: 07/20/2023] Open
Abstract
Copy number variation (CNV) can cause phenotypic changes. However, in contrast to amino acid substitutions and cis-regulatory changes, little is known about the functional categories of genes in which CNV is important for adaptation to novel environments. It is also unclear whether the same genes repeatedly change the copy numbers for adapting to similar environments. Here, we investigate CNV associated with freshwater colonization in fishes, which was observed multiple times across different lineages. Using 48 ray-finned fishes across diverse orders, we identified 23 genes whose copy number increases were associated with freshwater colonization. These genes showed enrichment for peptide receptor activity, hexosyltransferase activity and unsaturated fatty acid metabolism. We further revealed that three of the genes showed copy number increases in freshwater populations compared to marine ancestral populations of the stickleback genus Gasterosteus. These results indicate that copy number increases of genes involved in fatty acid metabolism (FADS2), immune function (PSMB8a) and thyroid hormone metabolism (UGT2) may be important for freshwater colonization at both the inter-order macroevolutionary scale and at the intra-genus microevolutionary scale. Further analysis across diverse taxa will help to understand the role of CNV in the adaptation to novel environments. This article is part of the theme issue 'Genetic basis of adaptation and speciation: from loci to causative mutations'.
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Affiliation(s)
- Asano Ishikawa
- Ecological Genetics Laboratory, National Institute of Genetics, Yata 1111, Mishima, Shizuoka 411-8540, Japan
- Department of Integrated Biosciences, Graduate School of Frontier Sciences, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8562, Japan
| | - Shun Yamanouchi
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, 2-11-16 Yayoi, Bunkyo-ku, Tokyo 113-0032, Japan
| | - Wataru Iwasaki
- Department of Integrated Biosciences, Graduate School of Frontier Sciences, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8562, Japan
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, 2-11-16 Yayoi, Bunkyo-ku, Tokyo 113-0032, Japan
| | - Jun Kitano
- Ecological Genetics Laboratory, National Institute of Genetics, Yata 1111, Mishima, Shizuoka 411-8540, Japan
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5
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Tsakoumis E, Ahi EP, Schmitz M. Impaired leptin signaling causes subfertility in female zebrafish. Mol Cell Endocrinol 2022; 546:111595. [PMID: 35139421 DOI: 10.1016/j.mce.2022.111595] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/20/2021] [Revised: 01/21/2022] [Accepted: 02/04/2022] [Indexed: 10/19/2022]
Abstract
Reproduction is an energetically costly event across vertebrates and tightly linked to nutritional status and energy reserves. In mammals, the hormone leptin is considered as a link between energy homeostasis and reproduction. However, its role in fish reproduction is still unclear. In this study, we investigated the possible role of leptin in the regulation of reproduction in zebrafish, using a loss of function leptin receptor (lepr) strain. Impaired leptin signaling resulted in severe reproductive deficiencies in female zebrafish. lepr mutant females laid significantly fewer eggs, with low fertilization rates compared to wild-type females. Folliculogenesis was not affected, but oocyte maturation and ovulation were disrupted in lepr mutants. Interestingly, the expression of luteinizing hormone beta (lhb) in the pituitary was significantly lower in mutant females. Analysis of candidate genes in the ovaries and isolated fully grown follicles revealed differential expression of genes involved in steroidogenesis, oocyte maturation and ovulation in the mutants, which are known to be regulated by LH signaling. Moreover, subfertility in lepr mutants could be partially restored by administration of human chorionic gonadotropin. In conclusion, our results show that leptin deficiency does not affect early stages of follicular development, but leptin might be essential in later steps, such as in oocyte maturation and ovulation. To our knowledge, this is the first time that leptin is associated to reproductive deficiencies in zebrafish.
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Affiliation(s)
- Emmanouil Tsakoumis
- Department of Organismal Biology, Environmental Toxicology, Evolutionary Biology Centre, Uppsala University, Uppsala, Sweden.
| | - Ehsan Pashay Ahi
- Organismal and Evolutionary Biology Research Program, University of Helsinki, Helsinki, Finland.
| | - Monika Schmitz
- Department of Organismal Biology, Environmental Toxicology, Evolutionary Biology Centre, Uppsala University, Uppsala, Sweden.
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6
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Mankiewicz JL, Picklo MJ, Idso J, Cleveland BM. Leptin Receptor Deficiency Results in Hyperphagia and Increased Fatty Acid Mobilization during Fasting in Rainbow Trout (Oncorhynchus mykiss). Biomolecules 2022; 12:biom12040516. [PMID: 35454105 PMCID: PMC9028016 DOI: 10.3390/biom12040516] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2022] [Revised: 03/15/2022] [Accepted: 03/26/2022] [Indexed: 12/19/2022] Open
Abstract
Leptin is a pleiotropic hormone known for regulating appetite and metabolism. To characterize the role of leptin signaling in rainbow trout, we used CRISPR/Cas9 genome editing to disrupt the leptin receptor (LepR) genes, lepra1 and lepra2. We compared wildtype (WT) and mutant fish that were either fed to satiation or feed deprived for six weeks. The LepR mutants exhibited a hyperphagic phenotype, which led to heavier body weight, faster specific growth rate, increased viscero- and hepatosomatic indices, and greater condition factor. Muscle glycogen, plasma leptin, and leptin transcripts (lepa1) were also elevated in fed LepR mutant fish. Expression levels of several hypothalamic genes involved in feed regulation were analyzed (agrp, npy, orexin, cart-1, cart-2, pomc-a1, pomc-b). No differences were detected between fed WT and mutants except for pomc-b (proopiomelanocortin-b), where levels were 7.5-fold higher in LepR fed mutants, suggesting that pomc-b expression is regulated by leptin signaling. Fatty acid (FA) content did not statistically differ in muscle of fed mutant fish compared to WT. However, fasted mutants exhibited significantly lower muscle FA concentrations, suggesting that LepR mutants exhibit increased FA mobilization during fasting. These data demonstrate a key role for leptin signaling in lipid and energy mobilization in a teleost fish.
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Affiliation(s)
- Jamie L. Mankiewicz
- National Center for Cool and Cold Water Aquaculture, USDA/ARS, Kearneysville, WV 25430, USA;
| | - Matthew J. Picklo
- Human Nutrition Research Center, USDA/ARS, 2420 2nd Ave. North, Grand Forks, ND 58203, USA; (M.J.P.); (J.I.)
| | - Joseph Idso
- Human Nutrition Research Center, USDA/ARS, 2420 2nd Ave. North, Grand Forks, ND 58203, USA; (M.J.P.); (J.I.)
| | - Beth M. Cleveland
- National Center for Cool and Cold Water Aquaculture, USDA/ARS, Kearneysville, WV 25430, USA;
- Correspondence:
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7
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Sivalingam M, Ogawa S, Trudeau VL, Parhar IS. Conserved functions of hypothalamic kisspeptin in vertebrates. Gen Comp Endocrinol 2022; 317:113973. [PMID: 34971635 DOI: 10.1016/j.ygcen.2021.113973] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Revised: 12/23/2021] [Accepted: 12/24/2021] [Indexed: 12/12/2022]
Abstract
Hypothalamic kisspeptin encoded by KISS1/Kiss1 gene emerged as a regulator of the reproductive axis in mammals following the discovery of the kisspeptin receptor (Kissr) and its role in reproduction. Kisspeptin-Kissr systems have been investigated in various vertebrates, and a conserved sequence of kisspeptin-Kissr has been identified in most vertebrate species except in the avian linage. In addition, multiple paralogs of kisspeptin sequences have been identified in the non-mammalian vertebrates. The allegedly conserved role of kisspeptin-Kissr in reproduction became debatable when kiss/kissr genes-deficient zebrafish and medaka showed no apparent effect on the onset of puberty, sexual development, maturation and reproductive capacity. Therefore, it is questionable whether the role of kisspeptin in reproduction is conserved among vertebrate species. Here we discuss from a comparative and evolutional aspect the diverse functions of kisspeptin and its receptor in vertebrates. Primarily this review focuses on the role of hypothalamic kisspeptin in reproductive and non-reproductive functions that are conserved in vertebrate species.
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Affiliation(s)
- Mageswary Sivalingam
- Brain Research Institute, Jeffery Cheah School of Medicine and Health Sciences, Monash University Malaysia, 47500 Bandar Sunway, Petaling Jaya, Selangor, Malaysia
| | - Satoshi Ogawa
- Brain Research Institute, Jeffery Cheah School of Medicine and Health Sciences, Monash University Malaysia, 47500 Bandar Sunway, Petaling Jaya, Selangor, Malaysia
| | - Vance L Trudeau
- Department of Biology, University of Ottawa, Ottawa, ON, Canada
| | - Ishwar S Parhar
- Brain Research Institute, Jeffery Cheah School of Medicine and Health Sciences, Monash University Malaysia, 47500 Bandar Sunway, Petaling Jaya, Selangor, Malaysia.
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8
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Zhang L, Wang F, Gao G, Yan X, Liu H, Liu Z, Wang Z, He L, Lv Q, Wang Z, Wang R, Zhang Y, Li J, Su R. Genome-Wide Association Study of Body Weight Traits in Inner Mongolia Cashmere Goats. Front Vet Sci 2021; 8:752746. [PMID: 34926636 PMCID: PMC8673091 DOI: 10.3389/fvets.2021.752746] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2021] [Accepted: 09/27/2021] [Indexed: 11/13/2022] Open
Abstract
Objective: Body weight is an important economic trait for a goat, which greatly affects animal growth and survival. The purpose of this study was to identify genes associated with birth weight (BW), weaning weight (WW), and yearling weight (YW). Materials and Methods: In this study, a genome-wide association study (GWAS) of BW, WW, and YW was determined using the GGP_Goat_70K single-nucleotide polymorphism (SNP) chip in 1,920 Inner Mongolia cashmere goats. Results: We discovered that 21 SNPs were significantly associated with BW on the genome-wide levels. These SNPs were located in 10 genes, e.g., Mitogen-Activated Protein Kinase 3 (MAPK3), LIM domain binding 2 (LDB2), and low-density lipoprotein receptor-related protein 1B (LRP1B), which may be related to muscle growth and development in Inner Mongolia Cashmere goats. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis revealed that these genes were significantly enriched in the regulation of actin cytoskeleton and phospholipase D signaling pathway etc. Conclusion: In summary, this study will improve the marker-assisted breeding of Inner Mongolia cashmere goats and the molecular mechanisms of important economic traits.
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Affiliation(s)
- Lei Zhang
- College of Animal Science, Inner Mongolia Agricultural University, Hohhot, China.,Inner Mongolia Jinlai Livestock Technology Co., Ltd, Hohhot, China
| | - Fenghong Wang
- College of Animal Science, Inner Mongolia Agricultural University, Hohhot, China
| | - Gong Gao
- College of Animal Science, Inner Mongolia Agricultural University, Hohhot, China
| | - Xiaochun Yan
- College of Animal Science, Inner Mongolia Agricultural University, Hohhot, China
| | - Hongfu Liu
- College of Animal Science, Inner Mongolia Agricultural University, Hohhot, China
| | - Zhihong Liu
- College of Animal Science, Inner Mongolia Agricultural University, Hohhot, China.,Key Laboratory of Animal Genetics, Breeding and Reproduction, Hohhot, China.,Key Laboratory of Mutton Sheep Genetics and Breeding, Ministry of Agriculture and Rural Affairs, Hohhot, China.,Engineering Research Center for Goat Genetics and Breeding, Hohhot, China
| | - Zhixin Wang
- College of Animal Science, Inner Mongolia Agricultural University, Hohhot, China.,Key Laboratory of Animal Genetics, Breeding and Reproduction, Hohhot, China.,Key Laboratory of Mutton Sheep Genetics and Breeding, Ministry of Agriculture and Rural Affairs, Hohhot, China
| | - Libing He
- Inner Mongolia Jinlai Livestock Technology Co., Ltd, Hohhot, China
| | - Qi Lv
- College of Animal Science, Inner Mongolia Agricultural University, Hohhot, China
| | - Zhiying Wang
- College of Animal Science, Inner Mongolia Agricultural University, Hohhot, China
| | - Ruijun Wang
- College of Animal Science, Inner Mongolia Agricultural University, Hohhot, China
| | - Yanjun Zhang
- College of Animal Science, Inner Mongolia Agricultural University, Hohhot, China.,Key Laboratory of Animal Genetics, Breeding and Reproduction, Hohhot, China.,Key Laboratory of Mutton Sheep Genetics and Breeding, Ministry of Agriculture and Rural Affairs, Hohhot, China.,Engineering Research Center for Goat Genetics and Breeding, Hohhot, China
| | - Jinquan Li
- College of Animal Science, Inner Mongolia Agricultural University, Hohhot, China.,Key Laboratory of Animal Genetics, Breeding and Reproduction, Hohhot, China.,Key Laboratory of Mutton Sheep Genetics and Breeding, Ministry of Agriculture and Rural Affairs, Hohhot, China.,Engineering Research Center for Goat Genetics and Breeding, Hohhot, China
| | - Rui Su
- College of Animal Science, Inner Mongolia Agricultural University, Hohhot, China
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Del Vecchio G, Murashita K, Verri T, Gomes AS, Rønnestad I. Leptin receptor-deficient (knockout) zebrafish: Effects on nutrient acquisition. Gen Comp Endocrinol 2021; 310:113832. [PMID: 34089707 DOI: 10.1016/j.ygcen.2021.113832] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/05/2021] [Revised: 04/22/2021] [Accepted: 06/01/2021] [Indexed: 12/18/2022]
Abstract
In mammals, knockout of LEPR results in a hyperphagic, morbid obese, and diabetic phenotype, which supports that leptin plays an important role in the control of appetite and energy metabolism, and that its receptor, LEPR, mediates these effects. To date, little is known about the role(s) of lepr in teleost physiology. We investigated a zebrafish (Danio rerio) homozygous lepr knockout (lepr-/-) line generated by CRISPR/Cas9 in comparison to its wt counterpart with respect to nutrient acquisition, energy allocation, and metabolism. The metabolic characterization included oxygen consumption rate and morphometric parameters (yolk sac area, standard length, wet weight, and condition factor) as proxies for use and allocation of energy in developing (embryos, larvae, and juveniles) zebrafish and showed no particular differences between the two lines, in agreement with previous studies. One exception was found in oxygen consumption at 72 hpf, when zebrafish switch from embryonic to early larval stages and food-seeking behavior could be observed. In this case, the metabolic rate was significantly lower in lepr-/- than in wt. Both phenotypes showed similar responses, with respect to metabolic rate, to acute alterations (22 and 34 °C) in water temperature (measured in terms of Q10 and activation energy) compared to the standard (28 °C) rearing conditions. To assess lepr involvement in signaling the processing and handling of incoming nutrients when an exogenous meal is digested and absorbed, we conducted an in vivo analysis in lepr-/- and wt early (8 days post-fertilization) zebrafish larvae. The larvae were administered a bolus of protein hydrolysate (0%, 1%, 5%, and 15% lactalbumin) directly into the digestive tract lumen, and changes in the mRNA expression profile before and after (1 and 3 h) administration were quantified. The analysis showed transcriptional differences in the expressions of genes involved in the control of appetite and energy metabolism (cart, npy, agrp, and mc4r), sensing (casr, t1r1, t1r3, t1r2-1, t1r2-2, pept1a, and pept1b), and digestion (cck, pyy, try, ct, and amy), with more pronounced effects observed in the orexigenic than in the anorexigenic pathways, suggesting a role of lepr in their regulations. Differences in the mRNA levels of these genes in lepr-/-vs. wt larvae were also observed. Altogether, our analyses suggest an influence of lepr on physiological processes involved in nutrient acquisition, mainly control of food intake and digestion, during early development, whereas metabolism, energy allocation, and growth seem to be only slightly influenced.
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Affiliation(s)
- Gianmarco Del Vecchio
- Department of Biological and Environmental Sciences and Technologies, University of Salento, Via Provinciale Lecce-Monteroni, I-73100 Lecce, Italy; Department of Biological Sciences, University of Bergen, PO Box 7803, NO-5020 Bergen, Norway
| | - Koji Murashita
- Department of Biological Sciences, University of Bergen, PO Box 7803, NO-5020 Bergen, Norway; Aquaculture Research Department, Fisheries Technology Institute, Fisheries Research and Education Agency, 224-1 Hiruda, Tamaki, Watarai, Mie 519-0423, Japan
| | - Tiziano Verri
- Department of Biological and Environmental Sciences and Technologies, University of Salento, Via Provinciale Lecce-Monteroni, I-73100 Lecce, Italy
| | - Ana S Gomes
- Department of Biological Sciences, University of Bergen, PO Box 7803, NO-5020 Bergen, Norway
| | - Ivar Rønnestad
- Department of Biological Sciences, University of Bergen, PO Box 7803, NO-5020 Bergen, Norway.
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10
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Hsieh YW, Tsai YW, Lai HH, Lai CY, Lin CY, Her GM. Depletion of Alpha-Melanocyte-Stimulating Hormone Induces Insatiable Appetite and Gains in Energy Reserves and Body Weight in Zebrafish. Biomedicines 2021; 9:biomedicines9080941. [PMID: 34440144 PMCID: PMC8392443 DOI: 10.3390/biomedicines9080941] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Revised: 07/24/2021] [Accepted: 07/27/2021] [Indexed: 12/23/2022] Open
Abstract
The functions of anorexigenic neurons secreting proopiomelanocortin (POMC)/alpha-melanocyte-stimulating hormone (α-MSH) of the melanocortin system in the hypothalamus in vertebrates are energy homeostasis, food intake, and body weight regulation. However, the mechanisms remain elusive. This article reports on zebrafish that have been genetically engineered to produce α-MSH mutants, α-MSH-7aa and α-MSH-8aa, selectively lacking 7 and 8 amino acids within the α-MSH region, but retaining most of the other normal melanocortin-signaling (Pomc-derived) peptides. The α-MSH mutants exhibited hyperphagic phenotypes leading to body weight gain, as observed in human patients and mammalian models. The actions of several genes regulating appetite in zebrafish are similar to those in mammals when analyzed using gene expression analysis. These include four selected orexigenic genes: Promelanin-concentrating hormone (pmch), agouti-related protein 2 (agrp2), neuropeptide Y (npy), and hypothalamic hypocretin/orexin (hcrt). We also study five selected anorexigenic genes: Brain-derived neurotrophic factor (bdnf), single-minded homolog 1-a (sim1a), corticotropin-releasing hormone b (crhb), thyrotropin-releasing hormone (trh), and prohormone convertase 2 (pcsk2). The orexigenic actions of α-MSH mutants are rescued completely after hindbrain ventricle injection with a synthetic analog of α-MSH and a melanocortin receptor agonist, Melanotan II. We evaluate the adverse effects of MSH depletion on energy balance using the Alamar Blue metabolic rate assay. Our results show that α-MSH is a key regulator of POMC signaling in appetite regulation and energy expenditure, suggesting that it might be a potential therapeutic target for treating human obesity.
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Affiliation(s)
- Yang-Wen Hsieh
- Department of Bioscience and Biotechnology, National Taiwan Ocean University, Keelung 202, Taiwan; (Y.-W.H.); (C.-Y.L.); (C.-Y.L.)
- Institute of Biopharmaceutical Sciences, National Yang Ming Chiao Tung University, Taipei 112, Taiwan;
| | - Yi-Wen Tsai
- Department of Family Medicine, Chang Gung Memorial Hospital, Keelung 204, Taiwan;
- College of Medicine, Chang Gung University, Taoyuan 333, Taiwan
| | - Hsin-Hung Lai
- Institute of Biopharmaceutical Sciences, National Yang Ming Chiao Tung University, Taipei 112, Taiwan;
| | - Chi-Yu Lai
- Department of Bioscience and Biotechnology, National Taiwan Ocean University, Keelung 202, Taiwan; (Y.-W.H.); (C.-Y.L.); (C.-Y.L.)
- Institute of Biopharmaceutical Sciences, National Yang Ming Chiao Tung University, Taipei 112, Taiwan;
| | - Chiu-Ya Lin
- Department of Bioscience and Biotechnology, National Taiwan Ocean University, Keelung 202, Taiwan; (Y.-W.H.); (C.-Y.L.); (C.-Y.L.)
- Institute of Biopharmaceutical Sciences, National Yang Ming Chiao Tung University, Taipei 112, Taiwan;
| | - Guor Mour Her
- Institute of Biopharmaceutical Sciences, National Yang Ming Chiao Tung University, Taipei 112, Taiwan;
- Correspondence: ; Tel.: +886-2-2826-7000 (ext. 67990)
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11
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Ahi EP, Tsakoumis E, Brunel M, Schmitz M. Transcriptional study reveals a potential leptin-dependent gene regulatory network in zebrafish brain. FISH PHYSIOLOGY AND BIOCHEMISTRY 2021; 47:1283-1298. [PMID: 34236575 PMCID: PMC8302498 DOI: 10.1007/s10695-021-00967-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Accepted: 05/12/2021] [Indexed: 06/01/2023]
Abstract
The signal mediated by leptin hormone and its receptor is a major regulator of body weight, food intake and metabolism. In mammals and many teleost fish species, leptin has an anorexigenic role and inhibits food intake by influencing the appetite centres in the hypothalamus. However, the regulatory connections between leptin and downstream genes mediating its appetite-regulating effects are still not fully explored in teleost fish. In this study, we used a loss of function leptin receptor zebrafish mutant and real-time quantitative PCR to assess brain expression patterns of several previously identified anorexigenic genes downstream of leptin signal under different feeding conditions (normal feeding, 7-day fasting, 2 and 6-h refeeding). These downstream factors include members of cart genes, crhb and gnrh2, as well as selected genes co-expressed with them based on a zebrafish co-expression database. Here, we found a potential gene expression network (GRN) comprising the abovementioned genes by a stepwise approach of identifying co-expression modules and predicting their upstream regulators. Among the transcription factors (TFs) predicted as potential upstream regulators of this GRN, we found expression pattern of sp3a to be correlated with transcriptional changes of the downstream gene network. Interestingly, the expression and transcriptional activity of Sp3 orthologous gene in mammals have already been implicated to be under the influence of leptin signal. These findings suggest a potentially conserved regulatory connection between leptin and sp3a, which is predicted to act as a transcriptional driver of a downstream gene network in the zebrafish brain.
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Affiliation(s)
- Ehsan Pashay Ahi
- Department of Organismal Biology, Comparative Physiology, Evolutionary Biology Centre, Uppsala University, Norbyvägen 18A, SE-752 36 Uppsala, Sweden
- Organismal and Evolutionary Biology Research Programme, University of Helsinki, Viikinkaari 9, 00014 Helsinki, Finland
| | - Emmanouil Tsakoumis
- Department of Organismal Biology, Comparative Physiology, Evolutionary Biology Centre, Uppsala University, Norbyvägen 18A, SE-752 36 Uppsala, Sweden
| | - Mathilde Brunel
- Department of Molecular Sciences, Swedish University of Agricultural Sciences, Allmas Allé 5, SE-750 07 Uppsala, Sweden
| | - Monika Schmitz
- Department of Organismal Biology, Comparative Physiology, Evolutionary Biology Centre, Uppsala University, Norbyvägen 18A, SE-752 36 Uppsala, Sweden
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12
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The probiotic Lactobacillus rhamnosus mimics the dark-driven regulation of appetite markers and melatonin receptors' expression in zebrafish (Danio rerio) larvae: Understanding the role of the gut microbiome. Comp Biochem Physiol B Biochem Mol Biol 2021; 256:110634. [PMID: 34119649 DOI: 10.1016/j.cbpb.2021.110634] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2021] [Revised: 05/05/2021] [Accepted: 06/07/2021] [Indexed: 01/15/2023]
Abstract
The use of probiotics has been recently considered a novel therapeutic strategy to prevent pathologies such as obesity; however, the specific mechanisms of action by which probiotics exert their beneficial effects on metabolic health remain unclear. The aim of the present study was to investigate the short-term effects of a probiotic Lactobacillus rhamnosus supplementation (PROB) on appetite regulation, growth-related markers, and microbiota diversity in zebrafish (Danio rerio) larvae, compared to a group subjected to a constant darkness photoperiod (DARK), as well as to evaluate the effects of both treatments on melatonin receptors' expression. After a 24 h treatment, both PROB and DARK conditions caused a significant increase in leptin a expression. Moreover, mRNA abundances of leptin b and proopiomelanocortin a were elevated in the PROB group, and DARK showed a similar tendency, supporting a negative regulation of appetite markers by the treatments. Moreover, both PROB and DARK also enhanced the abundances of melatonin receptors transcript (melatonin receptor 1 ba and bb) and protein (melatonin receptor 1) suggesting a potential involvement of melatonin in mediating these effects. Nevertheless, treatments did not exhibit a significant effect on the expression of most of the growth hormone/insulin-like growth factor axis genes evaluated. Finally, only the DARK condition significantly modulated gut microbiota diversity at such short time, altogether highlighting the rapid effects of this probiotic on modulating appetite regulatory and melatonin receptors' expression, without a concomitant variation of gut microbiota.
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Chen H, Liang X, Gu X, Zeng Q, Mao Z, Martyniuk CJ. Environmentally relevant concentrations of sertraline disrupts behavior and the brain and liver transcriptome of juvenile yellow catfish (Tachysurus fulvidraco): Implications for the feeding and growth axis. JOURNAL OF HAZARDOUS MATERIALS 2021; 409:124974. [PMID: 33450510 DOI: 10.1016/j.jhazmat.2020.124974] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/13/2020] [Revised: 12/10/2020] [Accepted: 12/23/2020] [Indexed: 06/12/2023]
Abstract
Sertraline (SER) is one of the most prevalent antidepressants detected in aquatic environments, but its impact on fish behavior and growth remain poorly understood. As such, behavior and growth were assessed in yellow catfish (Tachysurus fulvidraco) following SER exposure. SER induced shoaling, reduced food consumption and growth, and increased cannibalism at environmentally relevant concentrations. To ascertain toxicity mechanisms, acetylcholinesterase (AChE) activity and transcripts related to growth and feeding were measured. AChE activity was increased in fish exposed to 10 and 100 μg/L SER. Transcript levels of neuropeptide Y, somatostatin, growth hormone, and insulin growth factor 1 were reduced in the brain following SER exposure. RNA-seq conducted in brain and liver revealed that gene networks associated with feeding and growth (i.e. leptin expression networks in the brain and insulin signaling pathways in the liver) were altered, proposed to be associated with the decreased food intake and growth. The brain also accumulated SER, which may relate to neurobehavioral responses. Lastly, the main metabolite of SER, norsertraline, was detected in the liver, and may also relate to toxicity. This study uncovers mechanisms and key events proposed to lead to impaired behavior and growth after exposure to some antidepressants.
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Affiliation(s)
- Huihui Chen
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, China; State Key Laboratory of Developmental Biology of Freshwater Fish, College of Life Sciences, Hunan Normal University, Changsha 410081, China
| | - Xuefang Liang
- Inner Mongolia Key Laboratory of Environmental Pollution Control & Waste Resource Reuse, School of Ecology and Environment, Inner Mongolia University, Hohhot 010021, China
| | - Xiaohong Gu
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, China; Jiangsu Collaborative Innovation Center of Regional Modern Agriculture & Environmental Protection, Huaiyin Normal University, Huaian 223300, China.
| | - Qingfei Zeng
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, China
| | - Zhigang Mao
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, China
| | - Christopher J Martyniuk
- Department of Physiological Sciences and Center for Environmental and Human Toxicology, University of Florida Genetics Institute, Interdisciplinary Program in Biomedical Sciences Neuroscience, College of Veterinary Medicine, University of Florida, Gainesville, FL 32611, USA
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14
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Blanco AM, Soengas JL. Leptin signalling in teleost fish with emphasis in food intake regulation. Mol Cell Endocrinol 2021; 526:111209. [PMID: 33588023 DOI: 10.1016/j.mce.2021.111209] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/05/2020] [Revised: 01/14/2021] [Accepted: 02/05/2021] [Indexed: 12/13/2022]
Abstract
Leptin, the product of the obese (ob or Lep) gene, was first cloned in teleost fish in 2005, more than a decade after its identification in mammals. This was because bony fish and mammalian leptins share a very low amino acid sequence identity, which suggests different functionality of the leptin system in fish compared to that of mammals. Indeed, major differences are evident between the mammalian and fish leptin system. Thus, for instance, mammalian leptin is synthesized and released by the adipose tissue in response to the amount of fat depots, while several tissues (mainly the liver) are the main sources of leptin in fish, whose determining factors of production are still unclear. In mammals, the main physiological role for leptin is its involvement in the maintenance of energy balance by decreasing food intake and increasing energy expenditure, although a wide variety of actions have been attributed to this hormone (e.g., regulation of lipid and carbohydrate metabolism, reproduction and immune functions). In fish, available literature also points towards a multifunctional nature for leptin, although knowledge on its functions is limited. In this review, we offer an overview of teleostean leptin structure and mechanism of action, and discuss the available knowledge on the role of this hormone in food intake regulation in teleost fish, aiming to provide a comparative overview between the functioning of the teleostean and mammalian leptin systems.
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Affiliation(s)
- Ayelén Melisa Blanco
- Laboratorio de Fisioloxía Animal, Departamento de Bioloxía Funcional e Ciencias da Saúde, Facultade de Bioloxía and Centro de Investigación Mariña, Universidade de Vigo, Vigo, Pontevedra, Spain
| | - José Luis Soengas
- Laboratorio de Fisioloxía Animal, Departamento de Bioloxía Funcional e Ciencias da Saúde, Facultade de Bioloxía and Centro de Investigación Mariña, Universidade de Vigo, Vigo, Pontevedra, Spain.
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15
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Marvel M, Levavi-Sivan B, Wong TT, Zmora N, Zohar Y. Gnrh2 maintains reproduction in fasting zebrafish through dynamic neuronal projection changes and regulation of gonadotropin synthesis, oogenesis, and reproductive behaviors. Sci Rep 2021; 11:6657. [PMID: 33758252 PMCID: PMC7987954 DOI: 10.1038/s41598-021-86018-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2020] [Accepted: 01/29/2021] [Indexed: 01/31/2023] Open
Abstract
Restricted food intake, either from lack of food sources or endogenous fasting, during reproductive periods is a widespread phenomenon across the animal kingdom. Considering previous studies show the canonical upstream regulator of reproduction in vertebrates, the hypothalamic Gonadotropin-releasing hormone (Gnrh), is inhibited in some fasting animals, we sought to understand the neuroendocrine control of reproduction in fasted states. Here, we explore the roles of the midbrain neuropeptide, Gnrh2, in inducing reproduction via its pituitary prevalence, gonadotropin synthesis, gametogenesis, and reproductive outputs in the zebrafish model undergoing different feeding regimes. We discovered a fasting-induced four-fold increase in length and abundance of Gnrh2 neuronal projections to the pituitary and in close proximity to gonadotropes, whereas the hypothalamic Gnrh3 neurons are reduced by six-fold in length. Subsequently, we analyzed the functional roles of Gnrh2 by comparing reproductive parameters of a Gnrh2-depleted model, gnrh2-/-, to wild-type zebrafish undergoing different feeding conditions. We found that Gnrh2 depletion in fasted states compromises spawning success, with associated decreases in gonadotropin production, oogenesis, fecundity, and male courting behavior. Gnrh2 neurons do not compensate in other circumstances by which Gnrh3 is depleted, such as in gnrh3-/- zebrafish, implying that Gnrh2 acts to induce reproduction specifically in fasted zebrafish.
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Affiliation(s)
- Miranda Marvel
- grid.266673.00000 0001 2177 1144Department of Marine Biotechnology, Institute of Marine and Environmental Technology, University of Maryland Baltimore County, Baltimore, MD 21202 USA
| | - Berta Levavi-Sivan
- grid.9619.70000 0004 1937 0538Department of Animal Sciences, The Robert H. Smith Faculty of Agriculture, Food, and Environment, The Hebrew University of Jerusalem, 76100 Rehovot, Israel
| | - Ten-Tsao Wong
- grid.266673.00000 0001 2177 1144Department of Marine Biotechnology, Institute of Marine and Environmental Technology, University of Maryland Baltimore County, Baltimore, MD 21202 USA
| | - Nilli Zmora
- grid.266673.00000 0001 2177 1144Department of Marine Biotechnology, Institute of Marine and Environmental Technology, University of Maryland Baltimore County, Baltimore, MD 21202 USA
| | - Yonathan Zohar
- grid.266673.00000 0001 2177 1144Department of Marine Biotechnology, Institute of Marine and Environmental Technology, University of Maryland Baltimore County, Baltimore, MD 21202 USA
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16
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Pereira S, Cline DL, Glavas MM, Covey SD, Kieffer TJ. Tissue-Specific Effects of Leptin on Glucose and Lipid Metabolism. Endocr Rev 2021; 42:1-28. [PMID: 33150398 PMCID: PMC7846142 DOI: 10.1210/endrev/bnaa027] [Citation(s) in RCA: 62] [Impact Index Per Article: 20.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Indexed: 12/18/2022]
Abstract
The discovery of leptin was intrinsically associated with its ability to regulate body weight. However, the effects of leptin are more far-reaching and include profound glucose-lowering and anti-lipogenic effects, independent of leptin's regulation of body weight. Regulation of glucose metabolism by leptin is mediated both centrally and via peripheral tissues and is influenced by the activation status of insulin signaling pathways. Ectopic fat accumulation is diminished by both central and peripheral leptin, an effect that is beneficial in obesity-associated disorders. The magnitude of leptin action depends upon the tissue, sex, and context being examined. Peripheral tissues that are of particular relevance include the endocrine pancreas, liver, skeletal muscle, adipose tissues, immune cells, and the cardiovascular system. As a result of its potent metabolic activity, leptin is used to control hyperglycemia in patients with lipodystrophy and is being explored as an adjunct to insulin in patients with type 1 diabetes. To fully understand the role of leptin in physiology and to maximize its therapeutic potential, the mechanisms of leptin action in these tissues needs to be further explored.
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Affiliation(s)
- Sandra Pereira
- Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, Canada
| | - Daemon L Cline
- Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, Canada
| | - Maria M Glavas
- Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, Canada
| | - Scott D Covey
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, Canada
| | - Timothy J Kieffer
- Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, Canada.,Department of Surgery, University of British Columbia, Vancouver, Canada.,School of Biomedical Engineering, University of British Columbia, Vancouver, Canada
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