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Arellano JI, Duque A, Rakic P. A coming-of-age story: adult neurogenesis or adolescent neurogenesis in rodents? Front Neurosci 2024; 18:1383728. [PMID: 38505771 PMCID: PMC10948509 DOI: 10.3389/fnins.2024.1383728] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2024] [Accepted: 02/23/2024] [Indexed: 03/21/2024] Open
Abstract
It is surprising that after more than a century using rodents for scientific research, there are no clear, consensual, or consistent definitions for when a mouse or a rat becomes adult. Specifically, in the field of adult hippocampal neurogenesis, where this concept is central, there is a trend to consider that puberty marks the start of adulthood and is not uncommon to find 30-day-old mice being described as adults. However, as others discussed earlier, this implies an important bias in the perceived importance of this trait because functional studies are normally done at very young ages, when neurogenesis is at its peak, disregarding middle aged and old animals that exhibit very little generation of new neurons. In this feature article we elaborate on those issues and argue that research on the postnatal development of mice and rats in the last 3 decades allows to establish an adolescence period that marks the transition to adulthood, as occurs in other mammals. Adolescence in both rat and mice ends around postnatal day 60 and therefore this age can be considered the onset of adulthood in both species. Nonetheless, to account for inter-individual, inter-strain differences in maturation and for possible delays due to environmental and social conditions, 3 months of age might be a safer option to consider mice and rats bona fide adults, as suggested by The Jackson Labs.
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Affiliation(s)
- Jon I. Arellano
- Department of Neuroscience, Yale University, New Haven, CT, United States
| | - Alvaro Duque
- Department of Neuroscience, Yale University, New Haven, CT, United States
| | - Pasko Rakic
- Department of Neuroscience, Yale University, New Haven, CT, United States
- Kavli Institute for Neuroscience at Yale, Yale University, New Haven, CT, United States
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Zala SM, Church B, Potts WK, Knauer F, Penn DJ. Female scent accelerates growth of juvenile male mice. Sci Rep 2023; 13:7371. [PMID: 37147391 PMCID: PMC10163255 DOI: 10.1038/s41598-023-34548-3] [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: 01/20/2023] [Accepted: 05/03/2023] [Indexed: 05/07/2023] Open
Abstract
Exposing female house mice (Mus musculus) to male urinary scent accelerates their sexual development (Vandenbergh effect). Here, we tested whether exposing juvenile male mice to females' urine similarly influences male growth and size of their sexual organs. We exposed three-week old male house mice to female urine or water (control) for ca. three months. We found that female-exposed males grew significantly faster and gained more body mass than controls, despite all males being reared on a controlled diet, but we detected no differences in males' muscle mass or sexual organs. In contrast, exposing juvenile males to male urine had no effect their growth. We tested whether the males' accelerated growth imposed functional trade-offs on males' immune resistance to an experimental infection. We challenged the same male subjects with an avirulent bacterial pathogen (Salmonella enterica), but found no evidence that faster growth impacted their bacterial clearance, body mass or survival during infection compared to controls. Our results provide the first evidence to our knowledge that juvenile male mice accelerate their growth when exposed to the urine of adult females, though we found no evidence that increased growth had negative trade-offs on immune resistance to infectious disease.
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Affiliation(s)
- Sarah M Zala
- Konrad Lorenz Institute of Ethology, University of Veterinary Medicine, Vienna, Savoyenstrasse 1a, 1160, Vienna, Austria.
- Department of Biology, University of Utah, 257 S. 1400 E., Salt Lake City, UT, 84112, USA.
| | - Brian Church
- Department of Biology, University of Utah, 257 S. 1400 E., Salt Lake City, UT, 84112, USA
| | - Wayne K Potts
- Department of Biology, University of Utah, 257 S. 1400 E., Salt Lake City, UT, 84112, USA
| | - Felix Knauer
- Research Institute of Wildlife Ecology, University of Veterinary Medicine, Vienna, 1160, Vienna, Austria
| | - Dustin J Penn
- Konrad Lorenz Institute of Ethology, University of Veterinary Medicine, Vienna, Savoyenstrasse 1a, 1160, Vienna, Austria
- Department of Biology, University of Utah, 257 S. 1400 E., Salt Lake City, UT, 84112, USA
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Bartke A. Somatotropic Axis, Pace of Life and Aging. Front Endocrinol (Lausanne) 2022; 13:916139. [PMID: 35909509 PMCID: PMC9329927 DOI: 10.3389/fendo.2022.916139] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/08/2022] [Accepted: 06/17/2022] [Indexed: 12/01/2022] Open
Abstract
Mice with genetic growth hormone (GH) deficiency or GH resistance live much longer than their normal siblings maintained under identical conditions with unlimited access to food. Extended longevity of these mutants is associated with extension of their healthspan (period of life free of disability and disease) and with delayed and/or slower aging. Importantly, GH and GH-related traits have been linked to the regulation of aging and longevity also in mice that have not been genetically altered and in other mammalian species including humans. Avai+lable evidence indicates that the impact of suppressed GH signaling on aging is mediated by multiple interacting mechanisms and involves trade-offs among growth, reproduction, and longevity. Life history traits of long-lived GH-related mutants include slow postnatal growth, delayed sexual maturation, and reduced fecundity (smaller litter size and increased intervals between the litters). These traits are consistent with a slower pace-of-life, a well-documented characteristic of species of wild animals that are long-lived in their natural environment. Apparently, slower pace-of-life (or at least some of its features) is associated with extended longevity both within and between species. This association is unexpected and may appear counterintuitive, because the relationships between adult body size (a GH-dependent trait) and longevity within and between species are opposite rather than similar. Studies of energy metabolism and nutrient-dependent signaling pathways at different stages of the life course will be needed to elucidate mechanisms of these relationships.
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Tenuta M, Carlomagno F, Cangiano B, Kanakis G, Pozza C, Sbardella E, Isidori AM, Krausz C, Gianfrilli D. Somatotropic-Testicular Axis: A crosstalk between GH/IGF-I and gonadal hormones during development, transition, and adult age. Andrology 2020; 9:168-184. [PMID: 33021069 DOI: 10.1111/andr.12918] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Revised: 07/31/2020] [Accepted: 09/28/2020] [Indexed: 12/24/2022]
Abstract
BACKGROUND The hypothalamic-pituitary-gonadal (HPG) and hypothalamic-pituitary-somatotropic (HPS) axes are strongly interconnected. Interactions between these axes are complex and poorly understood. These interactions are characterized by redundancies in reciprocal influences at each level of regulation and the combination of endocrine and paracrine effects that change during development. OBJECTIVES To comprehensively review the crosstalk between the HPG and HPS axes and related pathological and clinical aspects during various life stages of male subjects. MATERIALS AND METHODS A thorough search of publications available in PubMed was performed using proper keywords. RESULTS Molecular studies confirmed the expressions of growth hormone (GH) and insulin-like growth factor-I (IGF-I) receptors on the HPG axis and reproductive organs, indicating a possible interaction between HPS and HPG axes at various levels. Insulin growth factors participate in sexual differentiation during fetal development, indicating that normal HPS axis activity is required for proper testicular development. IGF-I contributes to correct testicular position during minipuberty, determines linear growth during childhood, and promotes puberty onset and pace through gonadotropin-releasing hormone activation. IGF-I levels are high during transition age, even when linear growth is almost complete, suggesting its role in reproductive tract maturation. Patients with GH deficiency (GHD) and insensitivity (GHI) exhibit delayed puberty and impaired genital development; replacement therapy in such patients induces proper pubertal development. In adults, few studies have suggested that lower IGF-I levels are associated with impaired sperm parameters. DISCUSSION AND CONCLUSION The role of GH-IGF-I in testicular development remains largely unexplored. However, it is important to evaluate gonadic development in children with GHD. Additionally, HPS axis function should be evaluated in children with urogenital malformation or gonadal development alterations. Correct diagnosis and prompt therapeutic intervention are needed for healthy puberty, attainment of complete gonadal development during transition age, and fertility potential in adulthood.
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Affiliation(s)
- Marta Tenuta
- Department of Experimental Medicine, Sapienza University, Rome, Italy
| | | | - Biagio Cangiano
- Department of Clinical Sciences and Community Health, University of Milan, Milan, Italy
| | - George Kanakis
- Athens Naval and Veterans Affairs Hospital, Athens, Greece
| | - Carlotta Pozza
- Department of Experimental Medicine, Sapienza University, Rome, Italy
| | - Emilia Sbardella
- Department of Experimental Medicine, Sapienza University, Rome, Italy
| | - Andrea M Isidori
- Department of Experimental Medicine, Sapienza University, Rome, Italy
| | - Csilla Krausz
- Department of Experimental and Clinical Biomedical Sciences "Mario Serio", University of Florence, Florence, Italy
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Iwase H, Ball S, Adams K, Eyestone W, Walters A, Cooper DKC. Growth hormone receptor knockout: Relevance to xenotransplantation. Xenotransplantation 2020; 28:e12652. [PMID: 33058285 DOI: 10.1111/xen.12652] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Revised: 09/03/2020] [Accepted: 09/15/2020] [Indexed: 02/06/2023]
Abstract
Xenotransplantation research has made considerable progress in recent years, largely through the increasing availability of pigs with multiple genetic modifications, effective immunosuppressive therapy, and anti-inflammatory therapy to protect pig tissues from the primate immune and inflammatory responses and correct molecular incompatibilities. Further study is required regarding identification and investigation of physiological incompatibilities. Although the exact cause remains uncertain, we and others have observed relatively rapid growth of kidney xenografts after transplantation into nonhuman primates (NHPs). There has also been some evidence of growth, or at least ventricular hypertrophy, of the pig heart after orthotopic transplantation into NHPs. Rapid growth could be problematic, particularly with regard to the heart within the relatively restricted confines of the chest. It has been suggested that the problem of rapid growth of the pig organ after transplantation could be resolved by growth hormone receptor (GHR) gene knockout in the pig. The GHR, although most well-known for regulating growth, has many other biological functions, including regulating metabolism and controlling physiological processes. Genetically modified GHRKO pigs have recently become available. We provide data on their growth compared to comparable pigs that do not include GHRKO, and we have reviewed the literature regarding the effect of GHRKO, and its relevance to xenotransplantation.
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Affiliation(s)
- Hayato Iwase
- Xenotransplantation Program, Department of Surgery, University of Alabama at Birmingham, Birmingham, AL, USA
| | | | | | | | | | - David K C Cooper
- Xenotransplantation Program, Department of Surgery, University of Alabama at Birmingham, Birmingham, AL, USA
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Martini M, Froment P, Franceschini I, Pillon D, Guibert E, Cahier C, Mhaouty-Kodja S, Keller M. Perinatal Exposure to Methoxychlor Affects Reproductive Function and Sexual Behavior in Mice. Front Endocrinol (Lausanne) 2020; 11:639. [PMID: 33013709 PMCID: PMC7509471 DOI: 10.3389/fendo.2020.00639] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/25/2020] [Accepted: 08/06/2020] [Indexed: 01/07/2023] Open
Abstract
Numerous chemicals derived from human activity are now disseminated in the environment where their exert estrogenic endocrine disrupting effects, and therefore represent major health concerns. The present study explored whether Methoxychlor (MXC), an insecticide with xenoestrogens activities, given during the perinatal period (from gestational day 11 to postnatal day 8) and at an environmentally dose [20 μg/kg (body weight)/day], would affect reproductive physiology and sexual behavior of the offspring in mice. While MXC exposure did not induce any differences in the weight gain of animals from birth to 4 months of age, a clear difference (although in opposite direction according to the sexes) was observed on the anogenital distance between intact and exposed animals. A similar effect was also observed on preputial separation and vaginal opening, which reflects, respectively, in males and females, puberty occurrence. The advanced puberty observed in females was associated with an enhanced expression of kisspeptin cells in the anteroventral periventricular region of the medial preoptic area. Exposure to MXC did not induce in adult females changes in the estrous cycle or in the weight of the female reproductive tract. By contrast, males showed reduced weight of the epididymis and seminiferous vesicles associated with reduced testosterone levels and seminiferous tubule diameter. We also showed that both males and females showed deficits in mate preference tests. As a whole, our results show that MXC impacts reproductive outcomes.
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Affiliation(s)
- Mariangela Martini
- Physiologie de la Reproduction et des Comportements, UMR 7247 INRA/CNRS/Université François Rabelais, Nouzilly, France
- Department of Biological Sciences & Toxicology Program, North Carolina State University, Raleigh, NC, United States
| | - Pascal Froment
- Physiologie de la Reproduction et des Comportements, UMR 7247 INRA/CNRS/Université François Rabelais, Nouzilly, France
| | - Isabelle Franceschini
- Physiologie de la Reproduction et des Comportements, UMR 7247 INRA/CNRS/Université François Rabelais, Nouzilly, France
| | - Delphine Pillon
- Physiologie de la Reproduction et des Comportements, UMR 7247 INRA/CNRS/Université François Rabelais, Nouzilly, France
| | - Edith Guibert
- Physiologie de la Reproduction et des Comportements, UMR 7247 INRA/CNRS/Université François Rabelais, Nouzilly, France
| | - Claude Cahier
- Unité Expérimentale de Physiologie Animale de l'Orfrasière, UE 1297, INRA, Nouzilly, France
| | - Sakina Mhaouty-Kodja
- Sorbonne Université, CNRS, INSERM, Neuroscience Paris Seine - Institut de Biologie Paris Seine, Paris, France
| | - Matthieu Keller
- Physiologie de la Reproduction et des Comportements, UMR 7247 INRA/CNRS/Université François Rabelais, Nouzilly, France
- *Correspondence: Matthieu Keller
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Weger BD, Rawashdeh O, Gachon F. At the Intersection of Microbiota and Circadian Clock: Are Sexual Dimorphism and Growth Hormones the Missing Link to Pathology? Bioessays 2019; 41:e1900059. [DOI: 10.1002/bies.201900059] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2019] [Revised: 06/28/2019] [Indexed: 12/15/2022]
Affiliation(s)
- Benjamin D. Weger
- Institute of Bioengineering, School of Life SciencesEcole Polytechnique Fédérale de LausanneLausanne CH‐1015 Switzerland
| | - Oliver Rawashdeh
- School of Biomedical Science, Faculty of MedicineThe University of QueenslandSt. Lucia QLD‐4072 Australia
| | - Frédéric Gachon
- Institute for Molecular BioscienceThe University of QueenslandSt. Lucia QLD‐4072 Australia
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