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Junkins MS, Feng NY, Murphy LA, Curtis G, Merriman DK, Bagriantsev SN, Gracheva EO. Neural control of fluid homeostasis is engaged below 10°C in hibernation. Curr Biol 2024; 34:923-930.e5. [PMID: 38325375 DOI: 10.1016/j.cub.2024.01.035] [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: 05/14/2023] [Revised: 11/29/2023] [Accepted: 01/12/2024] [Indexed: 02/09/2024]
Abstract
Thirteen-lined ground squirrels (Ictidomys tridecemlineatus) hibernate for several months each winter without access to water,1 but the mechanisms that maintain fluid homeostasis during hibernation are poorly understood. In torpor, when body temperature (TB) reaches 4°C, squirrels decrease metabolism, slow heart rate, and reduce plasma levels of the antidiuretic hormones arginine vasopressin (AVP) and oxytocin (OXT).1 Squirrels spontaneously undergo interbout arousal (IBA) every 2 weeks, temporarily recovering an active-like metabolism and a TB of 37°C for up to 48 h.1,2 Despite the low levels of AVP and OXT during torpor, profound increases in blood pressure and heart rate during the torpor-IBA transition are not associated with massive fluid loss, suggesting the existence of a mechanism that protects against diuresis at a low TB. Here, we demonstrate that the antidiuretic hormone release pathway is activated by hypothalamic supraoptic nucleus (SON) neurons early in the torpor-arousal transition. SON neuron activity, dense-core vesicle release from the posterior pituitary, and plasma hormone levels all begin to increase before TB reaches 10°C. In vivo fiber photometry of SON neurons from hibernating squirrels, together with RNA sequencing and c-FOS immunohistochemistry, confirms that SON is electrically, transcriptionally, and translationally active to monitor blood osmolality throughout the dynamic torpor-arousal transition. Our work emphasizes the importance of the antidiuretic pathway during the torpor-arousal transition and reveals that the neurophysiological mechanism that coordinates the hormonal response to retain fluid is active at an extremely low TB, which is prohibitive for these processes in non-hibernators.
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Affiliation(s)
- Madeleine S Junkins
- Department of Cellular and Molecular Physiology, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06510, USA; Department of Neuroscience, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06510, USA; Department of Neuroscience and Program in Cellular Neuroscience, Neurodegeneration and Repair, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06510, USA
| | - Ni Y Feng
- Department of Cellular and Molecular Physiology, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06510, USA; Department of Neuroscience, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06510, USA; Department of Neuroscience and Program in Cellular Neuroscience, Neurodegeneration and Repair, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06510, USA; Neuroscience & Behavior Program, Wesleyan University, 52 Lawn Ave, Middletown, CT 06459, USA.
| | - Lyle A Murphy
- Department of Cellular and Molecular Physiology, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06510, USA
| | - Genevieve Curtis
- Department of Biology, Wesleyan University, 52 Lawn Ave, Middletown, CT 06459, USA
| | - Dana K Merriman
- Department of Biology, University of Wisconsin-Oshkosh, 800 Algoma Blvd, Oshkosh, WI 54901, USA
| | - Sviatoslav N Bagriantsev
- Department of Cellular and Molecular Physiology, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06510, USA.
| | - Elena O Gracheva
- Department of Cellular and Molecular Physiology, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06510, USA; Department of Neuroscience, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06510, USA; Department of Neuroscience and Program in Cellular Neuroscience, Neurodegeneration and Repair, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06510, USA; Kavli Institute for Neuroscience, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06510, USA.
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Relovska S, Wang H, Zhang X, Fernández-Tussy P, Jeong KJ, Choi J, Suárez Y, McDonald JG, Fernández-Hernando C, Chung JJ. DHCR24-mediated sterol homeostasis during spermatogenesis is required for sperm mitochondrial sheath formation and impacts male fertility over time. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.12.21.572851. [PMID: 38187697 PMCID: PMC10769317 DOI: 10.1101/2023.12.21.572851] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2024]
Abstract
Desmosterol and cholesterol are essential lipid components of the sperm plasma membrane. Cholesterol efflux is required for capacitation, a process through which sperm acquire fertilizing ability. In this study, using a transgenic mouse model overexpressing 24-dehydrocholesterol reductase (DHCR24), an enzyme in the sterol biosynthesis pathway responsible for the conversion of desmosterol to cholesterol, we show that disruption of sterol homeostasis during spermatogenesis led to defective sperm morphology characterized by incomplete mitochondrial packing in the midpiece, reduced sperm count and motility, and a decline in male fertility with increasing paternal age, without changes in body fat composition. Sperm depleted of desmosterol exhibit inefficiency in the acrosome reaction, metabolic dysfunction, and an inability to fertilize the egg. These findings provide molecular insights into sterol homeostasis for sperm capacitation and its impact on male fertility.
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Affiliation(s)
- Sona Relovska
- Department of Cellular and Molecular Physiology, Yale School of Medicine, New Haven, CT 06510, USA
| | - Huafeng Wang
- Department of Cellular and Molecular Physiology, Yale School of Medicine, New Haven, CT 06510, USA
| | - Xinbo Zhang
- Department of Comparative Medicine, Yale University School of Medicine, New Haven, CT 06510, USA
- Vascular Biology and Therapeutics Program, Yale University School of Medicine, New Haven, CT 06510, USA
| | - Pablo Fernández-Tussy
- Department of Comparative Medicine, Yale University School of Medicine, New Haven, CT 06510, USA
- Vascular Biology and Therapeutics Program, Yale University School of Medicine, New Haven, CT 06510, USA
| | - Kyung Jo Jeong
- Department of Biomedical Sciences, Korea University College of Medicine, Seoul, South Korea
| | - Jungmin Choi
- Department of Biomedical Sciences, Korea University College of Medicine, Seoul, South Korea
- Department of Genetics, Yale School of Medicine, Yale University, New Haven, Connecticut, USA
| | - Yajaira Suárez
- Department of Comparative Medicine, Yale University School of Medicine, New Haven, CT 06510, USA
- Vascular Biology and Therapeutics Program, Yale University School of Medicine, New Haven, CT 06510, USA
- Department of Pathology, Yale University School of Medicine, New Haven, CT 06510, USA
| | - Jeffrey G. McDonald
- Department of Immunobiology, Yale University School of Medicine, New Haven, CT 06510, USA
- Center for Human Nutrition, University of Texas Southwestern Medical Center, Dallas, TX 75390
| | - Carlos Fernández-Hernando
- Department of Comparative Medicine, Yale University School of Medicine, New Haven, CT 06510, USA
- Vascular Biology and Therapeutics Program, Yale University School of Medicine, New Haven, CT 06510, USA
- Department of Pathology, Yale University School of Medicine, New Haven, CT 06510, USA
| | - Jean-Ju Chung
- Department of Cellular and Molecular Physiology, Yale School of Medicine, New Haven, CT 06510, USA
- Department of Gynecology and Obstetrics, Yale School of Medicine, New Haven, CT 06510, USA
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