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Premachandran H, Wilkin J, Arruda-Carvalho M. Minimizing Variability in Developmental Fear Studies in Mice: Toward Improved Replicability in the Field. Curr Protoc 2024; 4:e1040. [PMID: 38713136 DOI: 10.1002/cpz1.1040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/08/2024]
Abstract
In rodents, the first weeks of postnatal life feature remarkable changes in fear memory acquisition, retention, extinction, and discrimination. Early development is also marked by profound changes in brain circuits underlying fear memory processing, with heightened sensitivity to environmental influences and stress, providing a powerful model to study the intersection between brain structure, function, and the impacts of stress. Nevertheless, difficulties related to breeding and housing young rodents, preweaning manipulations, and potential increased variability within that population pose considerable challenges to developmental fear research. Here we discuss several factors that may promote variability in studies examining fear conditioning in young rodents and provide recommendations to increase replicability. We focus primarily on experimental conditions, design, and analysis of rodent fear data, with an emphasis on mouse studies. The convergence of anatomical, synaptic, physiological, and behavioral changes during early life may increase variability, but careful practice and transparency in reporting may improve rigor and consensus in the field. © 2024 The Authors. Current Protocols published by Wiley Periodicals LLC.
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Affiliation(s)
- Hanista Premachandran
- Department of Psychology, University of Toronto Scarborough, Toronto, Ontario, Canada
- These authors contributed equally to this work
| | - Jennifer Wilkin
- Department of Psychology, University of Toronto Scarborough, Toronto, Ontario, Canada
- These authors contributed equally to this work
| | - Maithe Arruda-Carvalho
- Department of Psychology, University of Toronto Scarborough, Toronto, Ontario, Canada
- Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario, Canada
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2
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Park K, Park H, Chung C. Fear conditioning and extinction distinctively alter bidirectional synaptic plasticity within the amygdala of an animal model of post-traumatic stress disorder. Neurobiol Stress 2024; 29:100606. [PMID: 38292517 PMCID: PMC10825524 DOI: 10.1016/j.ynstr.2024.100606] [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: 10/06/2023] [Revised: 01/03/2024] [Accepted: 01/03/2024] [Indexed: 02/01/2024] Open
Abstract
Synaptic plasticity in the amygdala plays an essential role in the formation and inhibition of fear memory; however, this plasticity has mainly been studied in the lateral amygdala, making it largely uninvestigated in other subnuclei. Here, we investigated long-term potentiation (LTP) and long-term depression (LTD) in the basolateral amygdala (BLA) to the medial division of the central amygdala (CEm) synapses of juvenile C57BL/6N (B6) and 129S1/SvImJ (S1) mice. We found that in naïve B6 and S1 mice, LTP was not induced at the BLA to CEm synapses, whereas fear conditioning lowered the threshold for LTP induction in these synapses of both B6 and S1 mice. Interestingly, fear extinction disrupted the induction of LTP at the BLA to CEm synapses of B6 mice, whereas LTP was left intact in S1 mice. Both low-frequency stimulation (LFS) and modest LFS (mLFS) induced LTD in naïve B6 and S1 mice, suggesting that the BLA to CEm synapses express bidirectional plasticity. Fear conditioning disrupted both types of LTD induction selectively in S1 mice and LFS-LTD, presumably NMDAR-dependent LTD was partially recovered by fear extinction. However, mLFS-LTD which has been known to be endocannabinoid receptor 1 (CB1R)-dependent was not induced after fear extinction in both mouse strains. Our observations suggest that fear conditioning enhances LTP while fear extinction diminishes LTP at the BLA to the CEm synapses of B6 mice with successful extinction. Considering that S1 mice showed strong fear conditioning and impaired extinction, strong fear conditioning in the S1 strain may be related to disrupted LTD, and impaired extinction may be due to constant LTP and weak LFS-LTD at the BLA to CEm synapses. Our study contributes to the further understanding of the dynamics of synaptic potentiation and depression between the subnuclei of the amygdala in juvenile mice after fear conditioning and extinction.
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Affiliation(s)
- Kwanghoon Park
- Department of Biological Sciences, Konkuk University, Seoul, 05029, South Korea
| | - Hoyong Park
- Department of Biological Sciences, Konkuk University, Seoul, 05029, South Korea
| | - ChiHye Chung
- Department of Biological Sciences, Konkuk University, Seoul, 05029, South Korea
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3
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Ryherd GL, Bunce AL, Edwards HA, Baumgartner NE, Lucas EK. Sex differences in avoidance behavior and cued threat memory dynamics in mice: Interactions between estrous cycle and genetic background. Horm Behav 2023; 156:105439. [PMID: 37813043 PMCID: PMC10810684 DOI: 10.1016/j.yhbeh.2023.105439] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/20/2023] [Revised: 09/11/2023] [Accepted: 10/02/2023] [Indexed: 10/11/2023]
Abstract
Anxiety disorders are the most prevalent mental illnesses worldwide, exhibit high heritability, and affect twice as many women as men. To evaluate potential interactions between genetic background and cycling ovarian hormones on sex differences in susceptibility to negative valence behaviors relevant to anxiety disorders, we assayed avoidance behavior and cued threat memory dynamics in gonadally-intact adult male and female mice across four common inbred mouse strains: C57Bl/6J, 129S1/SVlmJ, DBA/2J, and BALB/cJ. Independent of sex, C57Bl/6J mice exhibited low avoidance but high threat memory, 129S1/SvlmJ mice high avoidance and high threat memory, DBA/2J mice low avoidance and low threat memory, and BALB/cJ mice high avoidance but low threat memory. Within-strain comparisons revealed reduced avoidance behavior in the high hormone phase of the estrous cycle (proestrus) compared to all other estrous phases in all strains except DBA/2J, which did not exhibit cycle-dependent behavioral fluctuations. Robust and opposing sex differences in threat conditioning and extinction training were found in the C57Bl/6J and 129S1/SvlmJ lines, whereas no sex differences were observed in the DBA/2J or BALB/cJ lines. C57Bl/6J males exhibited enhanced acute threat memory, whereas 129S1/SvlmJ females exhibited enhanced sustained threat memory, compared to their sex-matched littermates. These effects were not mediated by estrous cycle stage or sex differences in active versus passive defensive behavioral responses. Our data demonstrate that core features of behavioral endophenotypes relevant to anxiety disorders, such as avoidance and threat memory, are genetically driven yet dissociable and can be influenced further by cycling ovarian hormones.
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Affiliation(s)
- Garret L Ryherd
- Department of Molecular Biomedical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, NC, USA
| | - Averie L Bunce
- Department of Molecular Biomedical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, NC, USA
| | - Haley A Edwards
- Department of Molecular Biomedical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, NC, USA
| | - Nina E Baumgartner
- Department of Molecular Biomedical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, NC, USA; Department of Psychiatry & Behavioral Neurobiology, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Elizabeth K Lucas
- Department of Molecular Biomedical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, NC, USA; Department of Psychiatry & Behavioral Neurobiology, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, AL, USA.
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4
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Moore SJ, Cazares VA, Temme SJ, Murphy GG. Age-related deficits in neuronal physiology and cognitive function are recapitulated in young mice overexpressing the L-type calcium channel, Ca V 1.3. Aging Cell 2023; 22:e13781. [PMID: 36703244 PMCID: PMC10014069 DOI: 10.1111/acel.13781] [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: 09/01/2022] [Revised: 12/21/2022] [Accepted: 12/30/2022] [Indexed: 01/28/2023] Open
Abstract
The calcium dysregulation hypothesis of brain aging posits that an age-related increase in neuronal calcium concentration is responsible for alterations in a variety of cellular processes that ultimately result in learning and memory deficits in aged individuals. We previously generated a novel transgenic mouse line, in which expression of the L-type voltage-gated calcium, CaV 1.3, is increased by ~50% over wild-type littermates. Here, we show that, in young mice, this increase is sufficient to drive changes in neuronal physiology and cognitive function similar to those observed in aged animals. Specifically, there is an increase in the magnitude of the postburst afterhyperpolarization, a deficit in spatial learning and memory (assessed by the Morris water maze), a deficit in recognition memory (assessed in novel object recognition), and an overgeneralization of fear to novel contexts (assessed by contextual fear conditioning). While overexpression of CaV 1.3 recapitulated these key aspects of brain aging, it did not produce alterations in action potential firing rates, basal synaptic communication, or spine number/density. Taken together, these results suggest that increased expression of CaV 1.3 in the aged brain is a crucial factor that acts in concert with age-related changes in other processes to produce the full complement of structural, functional, and behavioral outcomes that are characteristic of aged animals.
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Affiliation(s)
- Shannon J. Moore
- Michigan Neuroscience InstituteAnn ArborMichiganUSA
- Molecular & Integrative PhysiologyUniversity of MichiganAnn ArborMichiganUSA
| | - Victor A. Cazares
- Molecular & Integrative PhysiologyUniversity of MichiganAnn ArborMichiganUSA
- Department of PsychologyWilliams CollegeWilliamstownMassachusettsUSA
| | | | - Geoffrey G. Murphy
- Michigan Neuroscience InstituteAnn ArborMichiganUSA
- Molecular & Integrative PhysiologyUniversity of MichiganAnn ArborMichiganUSA
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5
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Fritz EM, Pierre A, De Bundel D, Singewald N. Ghrelin receptor agonist MK0677 and overnight fasting do not rescue deficient fear extinction in 129S1/SvImJ mice. Front Psychiatry 2023; 14:1094948. [PMID: 36846243 PMCID: PMC9947350 DOI: 10.3389/fpsyt.2023.1094948] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/10/2022] [Accepted: 01/03/2023] [Indexed: 02/11/2023] Open
Abstract
The hunger hormone ghrelin has been implicated in the modulation of anxiety- and fear-related behaviors in rodents and humans, while its dysregulation may be associated with psychiatric illness. Along these lines, the ghrelin system has been suggested as a potential target to facilitate fear extinction, which is the main mechanism underlying cognitive behavioral therapy. So far, this hypothesis has not been tested in individuals that have difficulties to extinguish fear. Thus, we investigated pharmacological (ghrelin receptor agonist MK0677) and non-pharmacological (overnight fasting) strategies to target the ghrelin system in the 129S1/SvImJ (S1) mouse strain, which models the endophenotype of impaired fear extinction that has been associated with treatment resistance in anxiety and PTSD patients. MK0677 induced food intake and overnight fasting increased plasma ghrelin levels in S1 mice, suggesting that the ghrelin system is responsive in the S1 strain. However, neither systemic administration of MK0677 nor overnight fasting had an effect on fear extinction in S1 mice. Similarly, our groups previously reported that both interventions did not attenuate fear in extinction-competent C57BL/6J mice. In summary, our findings are in contrast to several studies reporting beneficial effects of GHSR agonism and overnight fasting on fear- and anxiety-related behaviors in rodents. Rather, our data agree with accumulating evidence of divergent behavioral effects of ghrelin system activation and underscore the hypothesis that potential benefits of targeting the ghrelin system in fear extinction may be dependent on factors (e.g., previous stress exposure) that are not yet fully understood.
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Affiliation(s)
- Eva Maria Fritz
- Department of Pharmacology and Toxicology, Institute of Pharmacy and CMBI, University of Innsbruck, Innsbruck, Austria
| | - Anouk Pierre
- Department of Pharmaceutical Sciences, Research Group Experimental Pharmacology, Center for Neurosciences (C4N), Vrije Universiteit Brussel, Brussels, Belgium
| | - Dimitri De Bundel
- Department of Pharmaceutical Sciences, Research Group Experimental Pharmacology, Center for Neurosciences (C4N), Vrije Universiteit Brussel, Brussels, Belgium
| | - Nicolas Singewald
- Department of Pharmacology and Toxicology, Institute of Pharmacy and CMBI, University of Innsbruck, Innsbruck, Austria
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Henn RE, Elzinga SE, Glass E, Parent R, Guo K, Allouch AM, Mendelson FE, Hayes J, Webber-Davis I, Murphy GG, Hur J, Feldman EL. Obesity-induced neuroinflammation and cognitive impairment in young adult versus middle-aged mice. Immun Ageing 2022; 19:67. [PMID: 36550567 PMCID: PMC9773607 DOI: 10.1186/s12979-022-00323-7] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2022] [Accepted: 12/05/2022] [Indexed: 12/24/2022]
Abstract
BACKGROUND Obesity rates are increasing worldwide. Obesity leads to many complications, including predisposing individuals to the development of cognitive impairment as they age. Immune dysregulation, including inflammaging (e.g., increased circulating cytokines) and immunosenescence (declining immune system function), commonly occur in obesity and aging and may impact cognitive impairment. As such, immune system changes across the lifespan may impact the effects of obesity on neuroinflammation and associated cognitive impairment. However, the role of age in obesity-induced neuroinflammation and cognitive impairment is unclear. To further define this putative relationship, the current study examined metabolic and inflammatory profiles, along with cognitive changes using a high-fat diet (HFD) mouse model of obesity. RESULTS First, HFD promoted age-related changes in hippocampal gene expression. Given this early HFD-induced aging phenotype, we fed HFD to young adult and middle-aged mice to determine the effect of age on inflammatory responses, metabolic profile, and cognitive function. As anticipated, HFD caused a dysmetabolic phenotype in both age groups. However, older age exacerbated HFD cognitive and neuroinflammatory changes, with a bi-directional regulation of hippocampal inflammatory gene expression. CONCLUSIONS Collectively, these data indicate that HFD promotes an early aging phenotype in the brain, which is suggestive of inflammaging and immunosenescence. Furthermore, age significantly compounded the impact of HFD on cognitive outcomes and on the regulation of neuroinflammatory programs in the brain.
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Affiliation(s)
- Rosemary E Henn
- Department of Neurology, University of Michigan, Ann Arbor, MI, 48109, USA
- NeuroNetwork for Emerging Therapies, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Sarah E Elzinga
- Department of Neurology, University of Michigan, Ann Arbor, MI, 48109, USA
- NeuroNetwork for Emerging Therapies, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Emily Glass
- Michigan Neuroscience Institute, University of Michigan, Ann Arbor, MI, 48109, USA
- Department of Molecular and Integrative Physiology, Division of Cardiovascular Medicine, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Rachel Parent
- Michigan Neuroscience Institute, University of Michigan, Ann Arbor, MI, 48109, USA
- Department of Molecular and Integrative Physiology, Division of Cardiovascular Medicine, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Kai Guo
- Department of Biomedical Sciences, University of North Dakota, Grand Forks, ND, 58202, USA
| | - Adam M Allouch
- Department of Neurology, University of Michigan, Ann Arbor, MI, 48109, USA
- NeuroNetwork for Emerging Therapies, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Faye E Mendelson
- Department of Neurology, University of Michigan, Ann Arbor, MI, 48109, USA
- NeuroNetwork for Emerging Therapies, University of Michigan, Ann Arbor, MI, 48109, USA
| | - John Hayes
- Department of Neurology, University of Michigan, Ann Arbor, MI, 48109, USA
- NeuroNetwork for Emerging Therapies, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Ian Webber-Davis
- Department of Neurology, University of Michigan, Ann Arbor, MI, 48109, USA
- NeuroNetwork for Emerging Therapies, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Geoffery G Murphy
- Michigan Neuroscience Institute, University of Michigan, Ann Arbor, MI, 48109, USA
- Department of Molecular and Integrative Physiology, Division of Cardiovascular Medicine, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Junguk Hur
- Department of Biomedical Sciences, University of North Dakota, Grand Forks, ND, 58202, USA
| | - Eva L Feldman
- Department of Neurology, University of Michigan, Ann Arbor, MI, 48109, USA.
- NeuroNetwork for Emerging Therapies, University of Michigan, Ann Arbor, MI, 48109, USA.
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7
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Tronson NC, Schuh KM. Hormonal contraceptives, stress, and the brain: The critical need for animal models. Front Neuroendocrinol 2022; 67:101035. [PMID: 36075276 DOI: 10.1016/j.yfrne.2022.101035] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/30/2022] [Revised: 07/26/2022] [Accepted: 09/01/2022] [Indexed: 01/10/2023]
Abstract
Hormonal contraceptives are among the most important health and economic developments in the 20thCentury, providing unprecedented reproductive control and a range of health benefits including decreased premenstrual symptoms and protections against various cancers. Hormonal contraceptives modulate neural function and stress responsivity. These changes are usually innocuous or even beneficial, including their effects onmood. However, in approximately 4-10% of users, or up to 30 million people at any given time, hormonal contraceptives trigger depression or anxiety symptoms. How hormonal contraceptives contribute to these responses and who is at risk for adverse outcomes remain unknown. In this paper, we discussstudies of hormonal contraceptive use in humans and describe the ways in which laboratory animal models of contraceptive hormone exposure will be an essential tool for expanding findings to understand the precise mechanisms by which hormonal contraceptives influence the brain, stress responses, and depression risk.
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Affiliation(s)
- Natalie C Tronson
- Department of Psychology, University of Michigan, Ann Arbor, MI, USA.
| | - Kristen M Schuh
- Department of Psychology, University of Michigan, Ann Arbor, MI, USA
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8
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Fritz EM, Kreuzer M, Altunkaya A, Singewald N, Fenzl T. Altered sleep behavior in a genetic mouse model of impaired fear extinction. Sci Rep 2021; 11:8978. [PMID: 33903668 PMCID: PMC8076259 DOI: 10.1038/s41598-021-88475-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2021] [Accepted: 04/13/2021] [Indexed: 02/03/2023] Open
Abstract
Sleep disturbances are a common complaint of anxiety patients and constitute a hallmark feature of post-traumatic stress disorder (PTSD). Emerging evidence suggests that poor sleep is not only a secondary symptom of anxiety- and trauma-related disorders but represents a risk factor in their development, for example by interfering with emotional memory processing. Fear extinction is a critical mechanism for the attenuation of fearful and traumatic memories and multiple studies suggest that healthy sleep is crucial for the formation of extinction memories. However, fear extinction is often impaired in anxiety- and trauma-related disorders-an endophenotype that is perfectly modelled in the 129S1/SvImJ inbred mouse strain. To investigate whether these mice exhibit altered sleep at baseline that could predispose them towards maladaptive fear processing, we compared their circadian sleep/wake patterns to those of typically extinction-competent C57BL/6 mice. We found significant differences regarding diurnal distribution of sleep and wakefulness, but also sleep architecture, spectral features and sleep spindle events. With regard to sleep disturbances reported by anxiety- and PTSD patients, our findings strengthen the 129S1/SvImJ mouse models' face validity and highlight it as a platform to investigate novel, sleep-focused diagnostic and therapeutic strategies. Whether the identified alterations causally contribute to its pathological anxiety/PTSD-like phenotype will, however, have to be addressed in future studies.
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Affiliation(s)
- Eva Maria Fritz
- Department of Pharmacology and Toxicology, Institute of Pharmacy and CMBI, University of Innsbruck, Innsbruck, Austria
| | - Matthias Kreuzer
- Department of Anesthesiology and Intensive Care, School of Medicine, Klinikum Rechts Der Isar, Technical University of Munich, Ismaninger Straße 22, 81675, Munich, Germany
| | - Alp Altunkaya
- Department of Anesthesiology and Intensive Care, School of Medicine, Klinikum Rechts Der Isar, Technical University of Munich, Ismaninger Straße 22, 81675, Munich, Germany
| | - Nicolas Singewald
- Department of Pharmacology and Toxicology, Institute of Pharmacy and CMBI, University of Innsbruck, Innsbruck, Austria
| | - Thomas Fenzl
- Department of Pharmacology and Toxicology, Institute of Pharmacy and CMBI, University of Innsbruck, Innsbruck, Austria.
- Department of Anesthesiology and Intensive Care, School of Medicine, Klinikum Rechts Der Isar, Technical University of Munich, Ismaninger Straße 22, 81675, Munich, Germany.
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9
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Rodriguez G, Moore SJ, Neff RC, Glass ED, Stevenson TK, Stinnett GS, Seasholtz AF, Murphy GG, Cazares VA. Deficits across multiple behavioral domains align with susceptibility to stress in 129S1/SvImJ mice. Neurobiol Stress 2020; 13:100262. [PMID: 33344715 PMCID: PMC7739066 DOI: 10.1016/j.ynstr.2020.100262] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2020] [Revised: 09/07/2020] [Accepted: 10/16/2020] [Indexed: 01/08/2023] Open
Abstract
Acute physical or psychological stress can elicit adaptive behaviors that allow an organism maintain homeostasis. However, intense and/or prolonged stressors often have the opposite effect, resulting in maladaptive behaviors and curbing goal-directed action; in the extreme, this may contribute to the development of psychiatric conditions like generalized anxiety disorder, major depressive disorder, or post-traumatic stress disorder. While treatment of these disorders generally focuses on reducing reactivity to potentially threatening stimuli, there are in fact impairments across multiple domains including valence, arousal, and cognition. Here, we use the genetically stress-susceptible 129S1 mouse strain to explore the effects of stress across multiple domains. We find that 129S1 mice exhibit a potentiated neuroendocrine response across many environments and paradigms, and that this is associated with reduced exploration, neophobia, decreased novelty- and reward-seeking, and spatial learning and memory impairments. Taken together, our results suggest that the 129S1 strain may provide a useful model for elucidating mechanisms underlying myriad aspects of stress-linked psychiatric disorders as well as potential treatments that may ameliorate symptoms.
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Affiliation(s)
- G Rodriguez
- Michigan Neuroscience Institute, USA.,Neuroscience Graduate Program, USA
| | - S J Moore
- Department of Molecular and Integrative Physiology, USA.,Michigan Neuroscience Institute, USA
| | - R C Neff
- Department of Molecular and Integrative Physiology, USA
| | - E D Glass
- Department of Molecular and Integrative Physiology, USA.,Michigan Neuroscience Institute, USA
| | | | | | - A F Seasholtz
- Michigan Neuroscience Institute, USA.,Neuroscience Graduate Program, USA.,Department of Biological Chemistry University of Michigan, Ann Arbor, MI, USA
| | - G G Murphy
- Department of Molecular and Integrative Physiology, USA.,Michigan Neuroscience Institute, USA.,Neuroscience Graduate Program, USA
| | - V A Cazares
- Department of Molecular and Integrative Physiology, USA.,Michigan Neuroscience Institute, USA.,Department of Psychology, Williams College, MA, USA
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10
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Sharkey LM, Sandoval-Pistorius SS, Moore SJ, Gerson JE, Komlo R, Fischer S, Negron-Rios KY, Crowley EV, Padron F, Patel R, Murphy GG, Paulson HL. Modeling UBQLN2-mediated neurodegenerative disease in mice: Shared and divergent properties of wild type and mutant UBQLN2 in phase separation, subcellular localization, altered proteostasis pathways, and selective cytotoxicity. Neurobiol Dis 2020; 143:105016. [PMID: 32653673 DOI: 10.1016/j.nbd.2020.105016] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2020] [Revised: 06/26/2020] [Accepted: 07/07/2020] [Indexed: 12/12/2022] Open
Abstract
The ubiquitin-binding proteasomal shuttle protein UBQLN2 is implicated in common neurodegenerative disorders due to its accumulation in disease-specific aggregates and, when mutated, directly causes familial frontotemporal dementia/amyotrophic lateral sclerosis (FTD/ALS). Like other proteins linked to FTD/ALS, UBQLN2 undergoes phase separation to form condensates. The relationship of UBQLN2 phase separation and accumulation to neurodegeneration, however, remains uncertain. Employing biochemical, neuropathological and behavioral assays, we studied the impact of overexpressing WT or mutant UBQLN2 in the CNS of transgenic mice. Expression of UBQLN2 harboring a pathogenic mutation (P506T) elicited profound and widespread intraneuronal inclusion formation and aggregation without prominent neurodegenerative or behavioral changes. Both WT and mutant UBQLN2 formed ubiquitin- and P62-positive inclusions in neurons, supporting the view that UBQLN2 is intrinsically prone to phase separate, with the size, shape and frequency of inclusions depending on expression level and the presence or absence of a pathogenic mutation. Overexpression of WT or mutant UBQLN2 resulted in a dose-dependent decrease in levels of a key interacting chaperone, HSP70, as well as dose-dependent profound degeneration of the retina. We conclude that, at least in mice, robust aggregation of a pathogenic form of UBQLN2 is insufficient to cause neuronal loss recapitulating that of human FTD/ALS. Our results nevertheless support the view that altering the normal cellular balance of UBQLN2, whether wild type or mutant protein, has deleterious effects on cells of the CNS and retina that likely reflect perturbations in ubiquitin-dependent protein homeostasis.
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Affiliation(s)
- Lisa M Sharkey
- Department of Neurology, University of Michigan, Ann Arbor, MI 48109-2200, United States of America.
| | - Stephanie S Sandoval-Pistorius
- Department of Neurology, University of Michigan, Ann Arbor, MI 48109-2200, United States of America; Neuroscience Graduate Program, University of Michigan, Ann Arbor, MI 48109, United States of America
| | - Shannon J Moore
- Michigan Neuroscience Institute and Department of Physiology, University of Michigan, Ann Arbor, MI 48109-2200, United States of America
| | - Julia E Gerson
- Department of Neurology, University of Michigan, Ann Arbor, MI 48109-2200, United States of America
| | - Robert Komlo
- Department of Neurology, University of Michigan, Ann Arbor, MI 48109-2200, United States of America
| | - Svetlana Fischer
- Department of Neurology, University of Michigan, Ann Arbor, MI 48109-2200, United States of America
| | - Keyshla Y Negron-Rios
- Department of Neurology, University of Michigan, Ann Arbor, MI 48109-2200, United States of America
| | - Emily V Crowley
- Department of Neurology, University of Michigan, Ann Arbor, MI 48109-2200, United States of America
| | - Francisco Padron
- Department of Neurology, University of Michigan, Ann Arbor, MI 48109-2200, United States of America
| | - Ronak Patel
- Department of Neurology, University of Michigan, Ann Arbor, MI 48109-2200, United States of America
| | - Geoffrey G Murphy
- Michigan Neuroscience Institute and Department of Physiology, University of Michigan, Ann Arbor, MI 48109-2200, United States of America
| | - Henry L Paulson
- Department of Neurology, University of Michigan, Ann Arbor, MI 48109-2200, United States of America.
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