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Uenoyama Y, Tsukamura H. KNDy neurones and GnRH/LH pulse generation: Current understanding and future aspects. J Neuroendocrinol 2023; 35:e13285. [PMID: 37232103 DOI: 10.1111/jne.13285] [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: 01/04/2023] [Revised: 03/31/2023] [Accepted: 04/26/2023] [Indexed: 05/27/2023]
Abstract
Uncovering the central mechanism underlying mammalian reproduction is warranted to develop new therapeutic approaches for reproductive disorders in humans and domestic animals. The present study focused on the role of arcuate kisspeptin neurones (also known as KNDy neurones) as an intrinsic gonadotropin-releasing hormone (GnRH) pulse generator, which plays a fundamental role in mammalian reproduction via the stimulation of pituitary gonadotropin synthesis and release and thereby in gametogenesis and steroidogenesis in the gonads of mammals. We also discuss the mechanism that inhibits pulsatile GnRH/gonadotropin release under a negative energy balance, considering that reproductive disorders often occur during malnutrition in humans and livestock.
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Affiliation(s)
| | - Hiroko Tsukamura
- Laboratory of Animal Reproduction, Nagoya University, Nagoya, Japan
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Hau RK, Wright SH, Cherrington NJ. In Vitro and In Vivo Models for Drug Transport Across the Blood-Testis Barrier. Drug Metab Dispos 2023; 51:1157-1168. [PMID: 37258305 PMCID: PMC10449102 DOI: 10.1124/dmd.123.001288] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2023] [Revised: 05/10/2023] [Accepted: 05/25/2023] [Indexed: 06/02/2023] Open
Abstract
The blood-testis barrier (BTB) is a selectively permeable membrane barrier formed by adjacent Sertoli cells (SCs) in the seminiferous tubules of the testes that develops intercellular junctional complexes to protect developing germ cells from external pressures. However, due to this inherent defense mechanism, the seminiferous tubule lumen can act as a pharmacological sanctuary site for latent viruses (e.g., Ebola, Zika) and cancers (e.g., leukemia). Therefore, it is critical to identify and evaluate BTB carrier-mediated drug delivery pathways to successfully treat these viruses and cancers. Many drugs are unable to effectively cross cell membranes without assistance from carrier proteins like transporters because they are large, polar, and often carry a charge at physiologic pH. SCs express transporters that selectively permit endogenous compounds, such as carnitine or nucleosides, across the BTB to support normal physiologic activity, although reproductive toxicants can also use these pathways, thereby circumventing the BTB. Certain xenobiotics, including select cancer therapeutics, antivirals, contraceptives, and environmental toxicants, are known to accumulate within the male genital tract and cause testicular toxicity; however, the transport pathways by which these compounds circumvent the BTB are largely unknown. Consequently, there is a need to identify the clinically relevant BTB transport pathways in in vitro and in vivo BTB models that recapitulate human pharmacokinetics and pharmacodynamics for these xenobiotics. This review summarizes the various in vitro and in vivo models of the BTB reported in the literature and highlights the strengths and weaknesses of certain models for drug disposition studies. SIGNIFICANCE STATEMENT: Drug disposition to the testes is influenced by the physical, physiological, and immunological components of the blood-testis barrier (BTB). But many compounds are known to cross the BTB by transporters, resulting in pharmacological and/or toxicological effects in the testes. Therefore, models that assess drug transport across the human BTB must adequately account for these confounding factors. This review identifies and discusses the benefits and limitations of various in vitro and in vivo BTB models for preclinical drug disposition studies.
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Affiliation(s)
- Raymond K Hau
- College of Pharmacy, Department of Pharmacology & Toxicology, (R.K.H., N.J.C.) and College of Medicine, Department of Physiology, The University of Arizona, Tucson, Arizona (S.H.W.)
| | - Stephen H Wright
- College of Pharmacy, Department of Pharmacology & Toxicology, (R.K.H., N.J.C.) and College of Medicine, Department of Physiology, The University of Arizona, Tucson, Arizona (S.H.W.)
| | - Nathan J Cherrington
- College of Pharmacy, Department of Pharmacology & Toxicology, (R.K.H., N.J.C.) and College of Medicine, Department of Physiology, The University of Arizona, Tucson, Arizona (S.H.W.)
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Ikegami K, Watanabe Y, Nakamura S, Goto T, Inoue N, Uenoyama Y, Tsukamura H. Cellular and molecular mechanisms regulating the KNDy neuronal activities to generate and modulate GnRH pulse in mammals. Front Neuroendocrinol 2022; 64:100968. [PMID: 34808231 DOI: 10.1016/j.yfrne.2021.100968] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/14/2021] [Revised: 10/18/2021] [Accepted: 11/15/2021] [Indexed: 12/30/2022]
Abstract
Accumulating findings during the past decades have demonstrated that the hypothalamic arcuate kisspeptin neurons are supposed to be responsible for pulsatile release of gonadotropin-releasing hormone (GnRH) to regulate gametogenesis and steroidogenesis in mammals. The arcuate kisspeptin neurons express neurokinin B (NKB) and dynorphin A (Dyn), thus, the neurons are also referred to as KNDy neurons. In the present article, we mainly focus on the cellular and molecular mechanisms underlying GnRH pulse generation, that is focused on the action of NKB and Dyn and an interaction between KNDy neurons and astrocytes to control GnRH pulse generation. Then, we also discuss the factors that modulate the activity of KNDy neurons and consequent pulsatile GnRH/LH release in mammals.
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Affiliation(s)
- Kana Ikegami
- Graduate School of Science, The University of Tokyo, Tokyo 113-0033, Japan
| | - Youki Watanabe
- Graduate School of Applied Life Science, Nippon Veterinary and Life Science University, Tokyo 180-8602, Japan
| | - Sho Nakamura
- Faculty of Veterinary Medicine, Okayama University of Science, Imabari, Ehime 794-8555, Japan
| | - Teppei Goto
- RIKEN Center for Biosystems Dynamics Research, Hyogo 650-0047, Japan
| | - Naoko Inoue
- Graduate School of Bioagricultural Science, Nagoya University, Nagoya 464-8601, Japan
| | - Yoshihisa Uenoyama
- Graduate School of Bioagricultural Science, Nagoya University, Nagoya 464-8601, Japan
| | - Hiroko Tsukamura
- Graduate School of Bioagricultural Science, Nagoya University, Nagoya 464-8601, Japan.
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Uenoyama Y, Nagae M, Tsuchida H, Inoue N, Tsukamura H. Role of KNDy Neurons Expressing Kisspeptin, Neurokinin B, and Dynorphin A as a GnRH Pulse Generator Controlling Mammalian Reproduction. Front Endocrinol (Lausanne) 2021; 12:724632. [PMID: 34566891 PMCID: PMC8458932 DOI: 10.3389/fendo.2021.724632] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/14/2021] [Accepted: 08/23/2021] [Indexed: 01/16/2023] Open
Abstract
Increasing evidence accumulated during the past two decades has demonstrated that the then-novel kisspeptin, which was discovered in 2001, the known neuropeptides neurokinin B and dynorphin A, which were discovered in 1983 and 1979, respectively, and their G-protein-coupled receptors, serve as key molecules that control reproduction in mammals. The present review provides a brief historical background and a summary of our recent understanding of the roles of hypothalamic neurons expressing kisspeptin, neurokinin B, and dynorphin A, referred to as KNDy neurons, in the central mechanism underlying gonadotropin-releasing hormone (GnRH) pulse generation and subsequent tonic gonadotropin release that controls mammalian reproduction.
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Abstract
The Tacr3 gene encodes tachykinin receptor 3 (NK3R), which belongs to the tachykinin receptor family. This family of proteins includes typical G protein-coupled receptors and belongs to the rhodopsin subfamily. NK3R functions by binding to its high-affinity ligand, neurokinin B(NKB). The role of Tacr3/NK3R in growth and reproduction has been extensively studied, but Tacr3/NK3R is also widely expressed in the nervous system from the spinal cord to the brain and is involved in both physiological and pathological processes in the nervous system, including mood disorders, chronic pain, learning and memory deficiencies, Alzheimer's disease, Parkinson's disease, addiction-related processes, hypoxic-ischemic encephalopathy, body fluid management, neural development, and schizophrenia. Here, we summarize the structure of NK3R/NKB and its cellular signaling as well as the expression of Tacr3/NK3R in the nervous system, and we provide a comprehensive summary of the role of Tacr3/NK3R in neurological diseases, including reproduction-related disorders and other neurological diseases. At the end of this review, we propose the hypothesis that Tacr3/NK3R mediates a variety of brain functions by affecting the excitability of different neurons with specific functions. On the basis of this "excited or not" hypothesis, more studies related to Tacr3 should be carried out in other nervous system diseases in order to better understand the biological roles of Tacr3.
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Affiliation(s)
- Wen-wen Zhang
- Department of Integrative Medicine and Neurobiology, Institutes of Integrative Medicine, School of Basic Medical Sciences, Institutes of Brain Science, Brain Science Collaborative Innovation Center, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Fudan University, Shanghai, China
| | - Yanqing Wang
- Department of Integrative Medicine and Neurobiology, Institutes of Integrative Medicine, School of Basic Medical Sciences, Institutes of Brain Science, Brain Science Collaborative Innovation Center, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Fudan University, Shanghai, China
| | - Yu-Xia Chu
- Department of Integrative Medicine and Neurobiology, Institutes of Integrative Medicine, School of Basic Medical Sciences, Institutes of Brain Science, Brain Science Collaborative Innovation Center, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Fudan University, Shanghai, China
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Son YW, Choi HN, Che JH, Kang BC, Yun JW. Advances in selecting appropriate non-rodent species for regulatory toxicology research: Policy, ethical, and experimental considerations. Regul Toxicol Pharmacol 2020; 116:104757. [PMID: 32758521 DOI: 10.1016/j.yrtph.2020.104757] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2020] [Revised: 07/27/2020] [Accepted: 07/31/2020] [Indexed: 12/20/2022]
Abstract
In vivo animal studies are required by regulatory agencies to investigate drug safety before clinical trials. In this review, we summarize the process of selecting a relevant non-rodent species for preclinical studies. The dog is the primary, default non-rodent used in toxicology studies with multiple scientific advantages, including adequate background data and availability. Rabbit has many regulatory advantages as the first non-rodent for the evaluation of reproductive and developmental as well as local toxicity. Recently, minipigs have increasingly replaced dogs and rabbits in toxicology studies due to ethical and scientific advantages including similarity to humans and breeding habits. When these species are not relevant, nonhuman primates (NHPs) can be used as the available animal models, especially in toxicology studies investigating biotherapeutics. Particularly, based on the phylogenetic relationships, the use of New-World marmosets can be considered before Old-World monkeys, especially cynomolgus with robust historical data. Importantly, the use of NHPs should be justified in terms of scientific benefits considering target affinity, expression pattern, and pharmacological cross-reactivity. Strict standards are required for the use of animals. Therefore, this review is helpful for the selection of appropriate non-rodent in regulatory toxicology studies by providing sufficient regulatory, ethical, and scientific data for each species.
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Affiliation(s)
- Yong-Wook Son
- Department of Biotechnology, The Catholic University of Korea, Bucheon, 14662, South Korea
| | - Ha-Ni Choi
- Department of Biotechnology, The Catholic University of Korea, Bucheon, 14662, South Korea
| | - Jeong-Hwan Che
- Biomedical Center for Animal Resource and Development, Seoul National University College of Medicine, Seoul, 03080, South Korea
| | - Byeong-Cheol Kang
- Graduate School of Translational Medicine, Seoul National University College of Medicine, Seoul, 03080, South Korea
| | - Jun-Won Yun
- Department of Biotechnology, The Catholic University of Korea, Bucheon, 14662, South Korea.
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Sasaki T, Sonoda T, Tatebayashi R, Kitagawa Y, Oishi S, Yamamoto K, Fujii N, Inoue N, Uenoyama Y, Tsukamura H, Maeda KI, Matsuda F, Morita Y, Matsuyama S, Ohkura S. Peripheral administration of SB223412, a selective neurokinin-3 receptor antagonist, suppresses pulsatile luteinizing hormone secretion by acting on the gonadotropin-releasing hormone pulse generator in estrogen-treated ovariectomized female goats. J Reprod Dev 2020; 66:351-357. [PMID: 32281549 PMCID: PMC7470901 DOI: 10.1262/jrd.2019-145] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Accumulating evidence suggests that KNDy neurons located in the hypothalamic arcuate nucleus (ARC), which are reported to express kisspeptin, neurokinin B, and dynorphin A, are indispensable for the gonadotropin-releasing hormone (GnRH) pulse generation that results in rhythmic GnRH secretion. The aims of the present study were to investigate the effects of peripheral administration of the neurokinin 3 receptor (NK3R/TACR3, a receptor for neurokinin B) antagonist, SB223412, on GnRH pulse-generating activity and pulsatile luteinizing hormone (LH) secretion in ovariectomized Shiba goats treated with luteal phase levels of estrogen. The NK3R antagonist was infused intravenously for 4 h {0.16 or 1.6 mg/(kg body weight [BW]·4 h)} during which multiple unit activity (MUA) in the ARC was recorded, an electrophysiological technique commonly employed to monitor GnRH pulse generator activity. In a separate experiment, the NK3R antagonist (40 or 200 mg/[kg BW·day]) was administered orally for 7 days to determine whether the NK3R antagonist could modulate pulsatile LH secretion when administered via the oral route. Intravenous infusion of the NK3R antagonist significantly increased the interval of episodic bursts of MUA compared with that of the controls. Oral administration of the antagonist for 7 days also significantly prolonged the interpulse interval of LH pulses. The results of this study demonstrate that peripheral administration of an NK3R antagonist suppresses pulsatile LH secretion by acting on the GnRH pulse generator, suggesting that NK3R antagonist administration could be used to modulate reproductive functions in ruminants.
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Affiliation(s)
- Takuya Sasaki
- Laboratory of Animal Production Science, Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya 464-8601, Japan
| | - Tomoya Sonoda
- Laboratory of Animal Production Science, Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya 464-8601, Japan
| | - Ryoki Tatebayashi
- Laboratory of Animal Production Science, Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya 464-8601, Japan
| | - Yuri Kitagawa
- Laboratory of Animal Production Science, Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya 464-8601, Japan
| | - Shinya Oishi
- Laboratory of Bioorganic Medicinal Chemistry, Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto 606-8501, Japan
| | - Koki Yamamoto
- Laboratory of Bioorganic Medicinal Chemistry, Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto 606-8501, Japan
| | - Nobutaka Fujii
- Laboratory of Bioorganic Medicinal Chemistry, Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto 606-8501, Japan
| | - Naoko Inoue
- Laboratory of Reproductive Science, Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya 464-8601, Japan
| | - Yoshihisa Uenoyama
- Laboratory of Reproductive Science, Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya 464-8601, Japan
| | - Hiroko Tsukamura
- Laboratory of Reproductive Science, Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya 464-8601, Japan
| | - Kei-Ichiro Maeda
- Laboratory of Theriogenology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo 113-8657, Japan
| | - Fuko Matsuda
- Laboratory of Theriogenology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo 113-8657, Japan
| | - Yasuhiro Morita
- Laboratory of Animal Production Science, Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya 464-8601, Japan
| | - Shuichi Matsuyama
- Laboratory of Animal Production Science, Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya 464-8601, Japan
| | - Satoshi Ohkura
- Laboratory of Animal Production Science, Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya 464-8601, Japan
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Tachykinins and Kisspeptins in the Regulation of Human Male Fertility. J Clin Med 2019; 9:jcm9010113. [PMID: 31906206 PMCID: PMC7019842 DOI: 10.3390/jcm9010113] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Revised: 12/24/2019] [Accepted: 12/27/2019] [Indexed: 12/21/2022] Open
Abstract
Infertility is a global disease affecting one out of six couples of reproductive age in the world, with a male factor involved in half the cases. There is still much to know about the regulation of human male fertility and thus we decided to focus on two peptide families that seem to play a key role in this function: tachykinins and kisspeptins. With this aim, we conducted an exhaustive review in order to describe the role of tachykinins and kisspeptins in human fertility and their possible implications in infertility etiopathogenesis. Many advances have been made to elucidate the roles of these two families in infertility, and multiple animal species have been studied, including humans. All of this knowledge could lead to new advances in male infertility diagnosis and treatment, but further research is needed to clarify all the implications of tachykinins and kisspeptins in fertility.
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SB223412, a neurokinin-3 receptor-selective antagonist, suppresses testosterone secretion in male guinea pigs. Theriogenology 2017; 102:183-189. [DOI: 10.1016/j.theriogenology.2017.07.053] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2017] [Revised: 07/28/2017] [Accepted: 07/29/2017] [Indexed: 11/23/2022]
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Vidal JD, Whitney KM. Morphologic manifestations of testicular and epididymal toxicity. SPERMATOGENESIS 2014; 4:e979099. [PMID: 26413388 DOI: 10.4161/21565562.2014.979099] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 07/18/2014] [Accepted: 10/16/2014] [Indexed: 11/19/2022]
Abstract
Histopathologic examination of the testis is the most sensitive means to detect effects on spermatogenesis; however, the complexity of testicular histology, interrelatedness of cell types within the testis, and long duration of spermatogenesis can make assessment of a testicular toxicant challenging. A thorough understanding of the histology and morphologic manifestations of response to injury is critical to successfully identify a testicular effect and to begin to understand the underlying mechanism of action. The basic patterns of response to xenobiotic-induced injury to the testis and epididymis are detailed and discussed.
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Noritake KI, Matsuoka T, Ohsawa T, Shimomura K, Sanbuissho A, Uenoyama Y, Maeda KI, Tsukamura H. Involvement of neurokinin receptors in the control of pulsatile luteinizing hormone secretion in rats. J Reprod Dev 2011; 57:409-15. [PMID: 21358144 DOI: 10.1262/jrd.11-002s] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
It has recently been shown that neurokinin B, a tachykinin, is associated with GnRH pulse generation in sheep and goats. The aim of the present study was to clarify the role of tachykinin receptors in the control of LH secretion in rats. To this end, we evaluated the effect of CS-003, an antagonist for all three neurokinin receptors (NK1, NK2 and NK3 receptors), on pulsatile LH secretion in both sexes of rats with different routes of administration. Both oral and third ventricular administration of CS-003 suppressed LH secretion in both sexes of gonadectomized animals. Furthermore, intact male rats with oral administration of CS-003 showed decreased serum testosterone levels, which might be due to suppressed LH secretion. None of the three subtype-specific neurokinin receptor antagonists showed a significant effect on LH secretion in ovariectomized rats when each antagonist was singly administered. The present results suggest that neurokinins play a role in the control of pulsatile GnRH/LH secretion via multiple neurokinin receptors in both male and female rats.
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Affiliation(s)
- Ken-ichi Noritake
- Medicinal Safety Research Laboratories, Daiichi Sankyo Co. Ltd., Shizuoka, Japan
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