1
|
Ogawa S, Yamamoto N, Hagio H, Oka Y, Parhar IS. Multiple gonadotropin-releasing hormone systems in non-mammalian vertebrates: Ontogeny, anatomy, and physiology. J Neuroendocrinol 2022; 34:e13068. [PMID: 34931380 DOI: 10.1111/jne.13068] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Revised: 11/17/2021] [Accepted: 11/19/2021] [Indexed: 01/08/2023]
Abstract
Three paralogous genes for gonadotropin-releasing hormone (GnRH; gnrh1, gnrh2, and gnrh3) and GnRH receptors exist in non-mammalian vertebrates. However, there are some vertebrate species in which one or two of these paralogous genes have become non-functional during evolution. The developmental migration of GnRH neurons in the brain is evolutionarily conserved in mammals, reptiles, birds, amphibians, and jawed teleost fish. The three GnRH paralogs have specific expression patterns in the brain and originate from multiple sites. In acanthopterygian teleosts (medaka, cichlid, etc.), the preoptic area (POA)-GnRH1 and terminal nerve (TN)-GnRH3 neuronal types originate from the olfactory regions. In other fish species (zebrafish, goldfish and salmon) with only two GnRH paralogs (GnRH2 and GnRH3), the TN- and POA-GnRH3 neuronal types share the same olfactory origin. However, the developmental origin of midbrain (MB)-GnRH2 neurons is debatable between mesencephalic or neural crest site. Each GnRH system has distinctive anatomical and physiological characteristics, and functions differently. The POA-GnRH1 neurons are hypophysiotropic in nature and function in the neuroendocrine control of reproduction. The non-hypophysiotropic GnRH2/GnRH3 neurons probably play neuromodulatory roles in metabolism (MB-GnRH2) and the control of motivational state for sexual behavior (TN-GnRH3).
Collapse
Affiliation(s)
- Satoshi Ogawa
- Jeffrey Cheah School of Medicine & Health Sciences, Monash University Malaysia, Selangor, Malaysia
| | - Naoyuki Yamamoto
- Laboratory of Fish Biology, Department of Animal Sciences, Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, Japan
| | - Hanako Hagio
- Laboratory of Fish Biology, Department of Animal Sciences, Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, Japan
- Institute for Advanced Research, Nagoya University, Nagoya, Japan
| | - Yoshitaka Oka
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan
| | - Ishwar S Parhar
- Jeffrey Cheah School of Medicine & Health Sciences, Monash University Malaysia, Selangor, Malaysia
| |
Collapse
|
2
|
Docampo-Seara A, Candal E, Rodríguez MA. Study of the glial cytoarchitecture of the developing olfactory bulb of a shark using immunochemical markers of radial glia. Brain Struct Funct 2022; 227:1067-1082. [PMID: 34997380 PMCID: PMC8930965 DOI: 10.1007/s00429-021-02448-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Accepted: 12/22/2021] [Indexed: 11/30/2022]
Abstract
During development of the olfactory bulb (OB), glial cells play key roles in axonal guiding/targeting, glomerular formation and synaptic plasticity. Studies in mammals have shown that radial glial cells and peripheral olfactory glia (olfactory ensheathing cells, OECs) are involved in the development of the OB. Most studies about the OB glia were carried out in mammals, but data are lacking in most non-mammalian vertebrates. In the present work, we studied the development of the OB glial system in the cartilaginous fish Scyliorhinus canicula (catshark) using antibodies against glial markers, such as glial fibrillary acidic protein (GFAP), brain lipid-binding protein (BLBP), and glutamine synthase (GS). These glial markers were expressed in cells with radial morphology lining the OB ventricle of embryos and this expression continues in ependymal cells (tanycytes) in early juveniles. Astrocyte-like cells were also observed in the granular layer and surrounding glomeruli. Numerous GS-positive cells were present in the primary olfactory pathway of embryos. In the developmental stages analysed, the olfactory nerve layer and the glomerular layer were the regions with higher GFAP, BLBP and GS immuno-reactivity. In addition, numerous BLBP-expressing cells (a marker of mammalian OECs) showing proliferative activity were present in the olfactory nerve layer. Our findings suggest that glial cells of peripheral and central origin coexist in the OB of catshark embryos and early juveniles. These results open the path for future studies about the differential roles of glial cells in the catshark OB during embryonic development and in adulthood.
Collapse
Affiliation(s)
- A Docampo-Seara
- Departamento de Bioloxía Funcional, Centro de Investigación en Bioloxía (CIBUS), Universidade de Santiago de Compostela, 15782, Santiago de Compostela, Spain.,UCL Institute of Ophthalmology, University College London, London, UK
| | - E Candal
- Departamento de Bioloxía Funcional, Centro de Investigación en Bioloxía (CIBUS), Universidade de Santiago de Compostela, 15782, Santiago de Compostela, Spain
| | - M A Rodríguez
- Departamento de Bioloxía Funcional, Centro de Investigación en Bioloxía (CIBUS), Universidade de Santiago de Compostela, 15782, Santiago de Compostela, Spain.
| |
Collapse
|
3
|
A comprehensive structural, lectin and immunohistochemical characterization of the zebrafish olfactory system. Sci Rep 2021; 11:8865. [PMID: 33893372 PMCID: PMC8065131 DOI: 10.1038/s41598-021-88317-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2020] [Accepted: 04/12/2021] [Indexed: 12/30/2022] Open
Abstract
Fish chemosensory olfactory receptors allow them to detect a wide range of water-soluble chemicals, that mediate fundamental behaviours. Zebrafish possess a well-developed sense of smell which governs reproduction, appetite, and fear responses. The spatial organization of functional properties within the olfactory epithelium and bulb are comparable to those of mammals, making this species suitable for studies of olfactory differentiation and regeneration and neuronal representation of olfactory information. The advent of genomic techniques has been decisive for the discovery of specific olfactory cell types and the identification of cell populations expressing vomeronasal receptors. These advances have marched ahead of morphological and neurochemical studies. This study aims to fill the existing gap in specific histological, lectin-histochemical and immunohistochemical studies on the olfactory rosette and the olfactory bulb of the zebrafish. Tissue dissection and microdissection techniques were employed, followed by histological staining techniques, lectin-histochemical labelling (UEA, LEA, BSI-B4) and immunohistochemistry using antibodies against G proteins subunits αo and αi2, growth-associated protein-43, calbindin, calretinin, glial-fibrillary-acidic-protein and luteinizing-hormone-releasing-hormone. The results obtained enrich the available information on the neurochemical patterns of the zebrafish olfactory system, pointing to a greater complexity than the one currently considered, especially when taking into account the peculiarities of the nonsensory epithelium.
Collapse
|
4
|
Palaniappan TK, Slekiene L, Gunhaga L, Patthey C. Extensive apoptosis during the formation of the terminal nerve ganglion by olfactory placode-derived cells with distinct molecular markers. Differentiation 2019; 110:8-16. [PMID: 31539705 DOI: 10.1016/j.diff.2019.09.003] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2019] [Revised: 08/30/2019] [Accepted: 09/02/2019] [Indexed: 12/20/2022]
Abstract
The terminal nerve ganglion (TNG) is a well-known structure of the peripheral nervous system in cartilaginous and teleost fishes. It derives from the olfactory placode during embryonic development. While the differentiation and migration of gonadotropin releasing hormone (GnRH)-expressing neurons from the olfactory placode has been well documented, the TNG has been neglected in birds and mammals, and its development is less well described. Here we describe the formation of a ganglion-like structure from migratory olfactory placodal cells in chicken. The TNG is surrounded by neural crest cells, but in contrast to other cranial sensory ganglia, we observed no neural crest corridor, and olfactory unsheathing cells appear only after the onset of neuronal migration. We identified Isl1 and Lhx2 as two transcription factors that label neuronal subpopulations in the forming TNG, distinct from GnRH1+ cells, thereby revealing a diversity of cell types during the formation of the TNG. We also provide evidence for extensive apoptosis in the terminal nerve ganglion shortly after its formation, but not in other cranial sensory ganglia. Moreover, at later stages placode-derived neurons expressing GnRH1, Isl1 and/or Lhx2 become incorporated in the telencephalon. The integration of TNG neurons into the telencephalon together with the earlier widespread apoptosis in the TNG might be an explanation why the TNG in mammals and birds is much smaller compared to other vertebrates.
Collapse
Affiliation(s)
| | - Lina Slekiene
- Umeå Centre for Molecular Medicine, Umeå University, 901 87, Umeå, Sweden
| | - Lena Gunhaga
- Umeå Centre for Molecular Medicine, Umeå University, 901 87, Umeå, Sweden
| | - Cedric Patthey
- Umeå Centre for Molecular Medicine, Umeå University, 901 87, Umeå, Sweden.
| |
Collapse
|
5
|
Taroc EZM, Prasad A, Lin JM, Forni PE. The terminal nerve plays a prominent role in GnRH-1 neuronal migration independent from proper olfactory and vomeronasal connections to the olfactory bulbs. Biol Open 2017; 6:1552-1568. [PMID: 28970231 PMCID: PMC5665474 DOI: 10.1242/bio.029074] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Gonadotropin-releasing hormone-1 (GnRH-1) neurons (GnRH-1 ns) migrate from the developing olfactory pit into the hypothalamus during embryonic development. Migration of the GnRH-1 neurons is required for mammalian reproduction as these cells control release of gonadotropins from the anterior pituitary gland. Disturbances in GnRH-1 ns migration, GnRH-1 synthesis, secretion or signaling lead to varying degrees of hypogonadotropic hypogonadism (HH), which impairs pubertal onset and fertility. HH associated with congenital olfactory defects is clinically defined as Kallmann Syndrome (KS). The association of olfactory defects with HH in KS suggested a potential direct relationship between defective olfactory axonal routing, lack of olfactory bulbs (OBs) and aberrant GnRH-1 ns migration. However, it has never been experimentally proven that the formation of axonal connections of the olfactory/vomeronasal neurons to their functional targets are necessary for the migration of GnRH-1 ns to the hypothalamus. Loss-of-function of the Arx-1 homeobox gene leads to the lack of proper formation of the OBs with abnormal axonal termination of olfactory sensory neurons (
Yoshihara et al., 2005). Our data prove that correct development of the OBs and axonal connection of the olfactory/vomeronasal sensory neurons to the forebrain are not required for GnRH-1 ns migration, and suggest that the terminal nerve, which forms the GnRH-1 migratory scaffold, follows different guidance cues and differs in gene expression from olfactory/vomeronasal sensory neurons. Summary: Our work reveals that correct olfactory bulb development is not required for GnRH-1 neuronal migration. This study challenges the idea that GnRH-1 neuronal migration to the hypothalamus relies on correct routing of the olfactory and vomeronasal neurons and supports the existence of the TN in mammals.
Collapse
Affiliation(s)
- Ed Zandro M Taroc
- Department of Biological Sciences, University at Albany, Albany, NY 12222, USA
| | - Aparna Prasad
- Department of Biological Sciences, University at Albany, Albany, NY 12222, USA
| | - Jennifer M Lin
- Department of Biological Sciences, University at Albany, Albany, NY 12222, USA
| | - Paolo E Forni
- Department of Biological Sciences, University at Albany, Albany, NY 12222, USA
| |
Collapse
|
6
|
D'aniello B, Luongo L, Rastogi RK, Di Meglio M, Pinelli C. Tract-tracing study of the extrabulbar olfactory projections in the brain of some teleosts. Microsc Res Tech 2015; 78:268-76. [PMID: 25663434 DOI: 10.1002/jemt.22471] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2014] [Accepted: 01/15/2015] [Indexed: 11/09/2022]
Abstract
The extrabulbar olfactory projections (EBOP) is a collection of nerve fibers that originate from primary olfactory receptor neurons. These fibers penetrate into the brain, bypassing the olfactory bulbs (OBs). While the presence of an EBOP has been well established in teleosts, here we morphologically characterize the EBOP structure in four species each with a different morphological relationship of OB with the ventral telencephalic area. Tract-tracing methods (carbocyanine DiI/DIA and biocytin) were used. FMRFamide immunoreactive nervus terminalis (NT) components were also visualized to define any neuroanatomical relationship between the NT and EBOP. Unilateral DiI/DiA application to the olfactory chamber stained the entire olfactory epithelium, olfactory nerve fibers, and ipsilateral olfactory bulb. Labeled primary olfactory fibers running ventromedially as extrabulbar primary olfactory projections reached various regions of the secondary prosencephalon. Only in Moenkhausia sanctaefilomenae (no olfactory peduncle) did lipophilic tracer-labeled fibers reach the ipsilateral mesencephalon. The combination of tracing techniques and FMRFamide immunohistochemistry revealed a substantial overlap of the label along the olfactory pathways as well as in the anterior secondary prosencephalon. However, FMRFamide immunoreactivity was never colocalized in the same cellular or fiber component as visualized using tracer molecules. Our results showed a certain uniformity in the neuroanatomy and extension of EBOP in all four species, independent of the pedunculate feature of the OBs. The present study also provided additional evidence to support the view that EBOP and FMRFamide immunoreactive components of the NT are separate anatomical entities.
Collapse
Affiliation(s)
- Biagio D'aniello
- Department of Biology, University of Naples Federico II, 80126, Naples, Italy
| | | | | | | | | |
Collapse
|