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Mangiamele LA, Dawn A, LeCure KM, Mantica GE, Racicot R, Fuxjager MJ, Preininger D. How new communication behaviors evolve: Androgens as modifiers of neuromotor structure and function in foot-flagging frogs. Horm Behav 2024; 161:105502. [PMID: 38382227 DOI: 10.1016/j.yhbeh.2024.105502] [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: 08/03/2023] [Revised: 12/08/2023] [Accepted: 02/05/2024] [Indexed: 02/23/2024]
Abstract
How diverse animal communication signals have arisen is a question that has fascinated many. Xenopus frogs have been a model system used for three decades to reveal insights into the neuroendocrine mechanisms and evolution of vocal diversity. Due to the ease of studying central nervous system control of the laryngeal muscles in vitro, Xenopus has helped us understand how variation in vocal communication signals between sexes and between species is produced at the molecular, cellular, and systems levels. Yet, it is becoming easier to make similar advances in non-model organisms. In this paper, we summarize our research on a group of frog species that have evolved a novel hind limb signal known as 'foot flagging.' We have previously shown that foot flagging is androgen dependent and that the evolution of foot flagging in multiple unrelated species is accompanied by the evolution of higher androgen hormone sensitivity in the leg muscles. Here, we present new preliminary data that compare patterns of androgen receptor expression and neuronal cell density in the lumbar spinal cord - the neuromotor system that controls the hind limb - between foot-flagging and non-foot-flagging frog species. We then relate our work to prior findings in Xenopus, highlighting which patterns of hormone sensitivity and neuroanatomical structure are shared between the neuromotor systems underlying Xenopus vocalizations and foot-flagging frogs' limb movement and which appear to be species-specific. Overall, we aim to illustrate the power of drawing inspiration from experiments in model organisms, in which the mechanistic details have been worked out, and then applying these ideas to a non-model species to reveal new details, further complexities, and fresh hypotheses.
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Affiliation(s)
- Lisa A Mangiamele
- Department of Biological Sciences, Smith College, Northampton, MA 01063, United States of America.
| | - AllexAndrya Dawn
- Department of Biological Sciences, Smith College, Northampton, MA 01063, United States of America
| | - Kerry M LeCure
- Department of Biological Sciences, Smith College, Northampton, MA 01063, United States of America
| | - Gina E Mantica
- Department of Biological Sciences, Smith College, Northampton, MA 01063, United States of America
| | - Riccardo Racicot
- Department of Biological Sciences, Smith College, Northampton, MA 01063, United States of America
| | - Matthew J Fuxjager
- Department of Ecology and Evolutionary Biology, Brown University, Providence, RI 02912, United States of America
| | - Doris Preininger
- Department of Evolutionary Biology, University of Vienna, Vienna, Austria; Vienna Zoo, Vienna, Austria
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2
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Cara AL, Burger LL, Beekly BG, Allen SJ, Henson EL, Auchus RJ, Myers MG, Moenter SM, Elias CF. Deletion of Androgen Receptor in LepRb Cells Improves Estrous Cycles in Prenatally Androgenized Mice. Endocrinology 2023; 164:bqad015. [PMID: 36683455 PMCID: PMC10091504 DOI: 10.1210/endocr/bqad015] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/24/2022] [Revised: 01/13/2023] [Accepted: 01/18/2023] [Indexed: 01/24/2023]
Abstract
Androgens are steroid hormones crucial for sexual differentiation of the brain and reproductive function. In excess, however, androgens may decrease fertility as observed in polycystic ovary syndrome, a common endocrine disorder characterized by oligo/anovulation and/or polycystic ovaries. Hyperandrogenism may also disrupt energy homeostasis, inducing higher central adiposity, insulin resistance, and glucose intolerance, which may exacerbate reproductive dysfunction. Androgens bind to androgen receptors (ARs), which are expressed in many reproductive and metabolic tissues, including brain sites that regulate the hypothalamo-pituitary-gonadal axis and energy homeostasis. The neuronal populations affected by androgen excess, however, have not been defined. We and others have shown that, in mice, AR is highly expressed in leptin receptor (LepRb) neurons, particularly in the arcuate (ARH) and the ventral premammillary nuclei (PMv). Here, we assessed if LepRb neurons, which are critical in the central regulation of energy homeostasis and exert permissive actions on puberty and fertility, have a role in the pathogenesis of female hyperandrogenism. Prenatally androgenized (PNA) mice lacking AR in LepRb cells (LepRbΔAR) show no changes in body mass, body composition, glucose homeostasis, or sexual maturation. They do show, however, a remarkable improvement of estrous cycles combined with normalization of ovary morphology compared to PNA controls. Our findings indicate that the prenatal androgenization effects on adult reproductive physiology (ie, anestrus and anovulation) are mediated by a subpopulation of LepRb neurons directly sensitive to androgens. They also suggest that the effects of hyperandrogenism on sexual maturation and reproductive function in adult females are controlled by distinct neural circuits.
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Affiliation(s)
- Alexandra L Cara
- Department of Molecular & Integrative Physiology, University of Michigan, Ann Arbor, Michigan 48109, USA
- Department of Integrative Biology and Physiology, University of California, Los Angeles, Los Angeles, California 90095, USA
| | - Laura L Burger
- Department of Molecular & Integrative Physiology, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - Bethany G Beekly
- Department of Molecular & Integrative Physiology, University of Michigan, Ann Arbor, Michigan 48109, USA
- Neuroscience Graduate Program, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - Susan J Allen
- Department of Molecular & Integrative Physiology, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - Emily L Henson
- Department of Molecular & Integrative Physiology, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - Richard J Auchus
- Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan 48109, USA
- Department of Pharmacology, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - Martin G Myers
- Department of Molecular & Integrative Physiology, University of Michigan, Ann Arbor, Michigan 48109, USA
- Neuroscience Graduate Program, University of Michigan, Ann Arbor, Michigan 48109, USA
- Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - Suzanne M Moenter
- Department of Molecular & Integrative Physiology, University of Michigan, Ann Arbor, Michigan 48109, USA
- Neuroscience Graduate Program, University of Michigan, Ann Arbor, Michigan 48109, USA
- Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan 48109, USA
- Department of Obstetrics and Gynecology, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - Carol F Elias
- Department of Molecular & Integrative Physiology, University of Michigan, Ann Arbor, Michigan 48109, USA
- Neuroscience Graduate Program, University of Michigan, Ann Arbor, Michigan 48109, USA
- Department of Obstetrics and Gynecology, University of Michigan, Ann Arbor, Michigan 48109, USA
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3
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Anderson NK, Goodwin SE, Schuppe ER, Dawn A, Preininger D, Mangiamele LA, Fuxjager MJ. Activational vs. organizational effects of sex steroids and their role in the evolution of reproductive behavior: Looking to foot-flagging frogs and beyond. Horm Behav 2022; 146:105248. [PMID: 36054981 DOI: 10.1016/j.yhbeh.2022.105248] [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: 05/25/2022] [Revised: 07/14/2022] [Accepted: 08/18/2022] [Indexed: 11/21/2022]
Abstract
Sex steroids play an important role in regulation of the vertebrate reproductive phenotype. This is because sex steroids not only activate sexual behaviors that mediate copulation, courtship, and aggression, but they also help guide the development of neural and muscular systems that underlie these traits. Many biologists have therefore described the effects of sex steroid action on reproductive behavior as both "activational" and "organizational," respectively. Here, we focus on these phenomena from an evolutionary standpoint, highlighting that we know relatively little about the way that organizational effects evolve in the natural world to support the adaptation and diversification of reproductive behavior. We first review the evidence that such effects do in fact evolve to mediate the evolution of sexual behavior. We then introduce an emerging animal model - the foot-flagging frog, Staurois parvus - that will be useful to study how sex hormones shape neuromotor development necessary for sexual displays. The foot flag is nothing more than a waving display that males use to compete for access to female mates, and thus the neural circuits that control its production are likely laid down when limb control systems arise during the developmental transition from tadpole to frog. We provide data that highlights how sex steroids might organize foot-flagging behavior through its putative underlying mechanisms. Overall, we anticipate that future studies of foot-flagging frogs will open a powerful window from which to see how sex steroids influence the neuromotor systems to help germinate circuits that drive signaling behavior. In this way, our aim is to bring attention to the important frontier of endocrinological regulation of evolutionary developmental biology (endo-evo-devo) and its relationship to behavior.
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Affiliation(s)
- Nigel K Anderson
- Department of Ecology, Evolution, and Organismal Biology, Brown University, Providence, RI, United States of America
| | - Sarah E Goodwin
- Department of Biological Sciences, Smith College, Northampton, MA, United States of America
| | - Eric R Schuppe
- Center for Integrative Neuroscience, University of California, San Francisco, San Francisco, CA, United States of America
| | - AllexAndrya Dawn
- Department of Biological Sciences, Smith College, Northampton, MA, United States of America
| | - Doris Preininger
- Department of Evolutionary Biology, University of Vienna, Vienna, Austria; Vienna Zoo, Vienna, Austria
| | - Lisa A Mangiamele
- Department of Biological Sciences, Smith College, Northampton, MA, United States of America.
| | - Matthew J Fuxjager
- Department of Ecology, Evolution, and Organismal Biology, Brown University, Providence, RI, United States of America.
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4
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Chew C, Sengelaub DR. Exercise is neuroprotective on the morphology of somatic motoneurons following the death of neighboring motoneurons via androgen action at the target muscle. Dev Neurobiol 2021; 81:22-35. [PMID: 33289343 PMCID: PMC10905969 DOI: 10.1002/dneu.22794] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2020] [Revised: 10/29/2020] [Accepted: 11/25/2020] [Indexed: 11/10/2022]
Abstract
Motoneuron loss is a severe medical problem that can result in loss of motor control and eventually death. We have previously demonstrated that partial motoneuron loss can result in dendritic atrophy and functional deficits in nearby surviving motoneurons, and that an androgen-dependent effect of exercise following injury can be neuroprotective against this dendritic atrophy. In this study, we explored where the necessary site of androgen action is for exercise-driven neuroprotective effects on induced dendritic atrophy. Motoneurons innervating the vastus medialis muscles of adult male rats were selectively killed by intramuscular injection of cholera toxin-conjugated saporin. Simultaneously, some saporin-injected animals were given implants of the androgen receptor antagonist hydroxyflutamide, either directly at the adjacent vastus lateralis musculature ipsilateral to the saporin-injected vastus medialis or interscapularly as a systemic control. Following saporin injections, some animals were allowed free access to a running wheel attached to their home cages. Four weeks later, motoneurons innervating the same vastus lateralis muscle were labeled with cholera toxin-conjugated horseradish peroxidase, and dendritic arbors were reconstructed in three dimensions. Dendritic arbor lengths of saporin-injected animals allowed to exercise were significantly longer than those not allowed to exercise. Androgen receptor blockade locally at the vastus lateralis muscle prevented the protective effect of exercise. These findings indicate that exercise following neural injury exerts a protective effect on motoneuron dendrites, which acts via androgen receptor action at the target muscle.
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Affiliation(s)
- Cory Chew
- Program in Neuroscience, Department of Psychological and Brain Sciences, Indiana University, Bloomington, IN, USA
| | - Dale R Sengelaub
- Program in Neuroscience, Department of Psychological and Brain Sciences, Indiana University, Bloomington, IN, USA
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Tobiansky DJ, Fuxjager MJ. Sex Steroids as Regulators of Gestural Communication. Endocrinology 2020; 161:5822602. [PMID: 32307535 PMCID: PMC7316366 DOI: 10.1210/endocr/bqaa064] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/10/2020] [Accepted: 04/16/2020] [Indexed: 12/13/2022]
Abstract
Gestural communication is ubiquitous throughout the animal kingdom, occurring in species that range from humans to arthropods. Individuals produce gestural signals when their nervous system triggers the production of limb and body movement, which in turn functions to help mediate communication between or among individuals. Like many stereotyped motor patterns, the probability of a gestural display in a given social context can be modulated by sex steroid hormones. Here, we review how steroid hormones mediate the neural mechanisms that underly gestural communication in humans and nonhumans alike. This is a growing area of research, and thus we explore how sex steroids mediate brain areas involved in language production, social behavior, and motor performance. We also examine the way that sex steroids can regulate behavioral output by acting in the periphery via skeletal muscle. Altogether, we outline a new avenue of behavioral endocrinology research that aims to uncover the hormonal basis for one of the most common modes of communication among animals on Earth.
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Affiliation(s)
- Daniel J Tobiansky
- Department of Ecology and Evolutionary Biology, Brown University, Providence, Rhode Island
- Correspondence: Daniel J. Tobiansky, Department of Ecology and Evolutionary Biology, Brown University, Providence, RI 02912.
| | - Matthew J Fuxjager
- Department of Ecology and Evolutionary Biology, Brown University, Providence, Rhode Island
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Deficiency in Androgen Receptor Aggravates the Depressive-Like Behaviors in Chronic Mild Stress Model of Depression. Cells 2019; 8:cells8091021. [PMID: 31480771 PMCID: PMC6769639 DOI: 10.3390/cells8091021] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2019] [Revised: 08/22/2019] [Accepted: 08/28/2019] [Indexed: 02/06/2023] Open
Abstract
While androgen receptor (AR) and stress may influence the development of the major depressive disorder (MDD), the detailed relationship, however, remains unclear. Here we found loss of AR accelerated development of depressive-like behaviors in mice under chronic mild stress (CMS). Mechanism dissection indicated that AR might function via altering the expression of miR-204-5p to modulate the brain-derived neurotrophic factor (BDNF) expression to influence the depressive-like behaviors in the mice under the CMS. Adding the antiandrogen flutamide with the stress hormone corticosterone can additively decrease BDNF mRNA in mouse hippocampus mHippoE-14 cells, which can then be reversed via down-regulating the miR-204-5p expression. Importantly, targeting this newly identified AR-mediated miR-204-5p/BDNF/AKT/MAPK signaling with small molecules including 7,8-DHF and fluoxetine, all led to alter the depressive-like behavior in AR knockout mice under CMS exposure. Together, results from these preclinical studies conclude that decreased AR may accelerate the stress-induced MDD via altering miR-204-5p/BDNF/AKT/MAPK signaling, and targeting this newly identified signaling may help in the development of better therapeutic approaches to reduce the development of MDD.
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Bollinger JL, Salinas I, Fender E, Sengelaub DR, Wellman CL. Gonadal hormones differentially regulate sex-specific stress effects on glia in the medial prefrontal cortex. J Neuroendocrinol 2019; 31:e12762. [PMID: 31228875 PMCID: PMC6715499 DOI: 10.1111/jne.12762] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/27/2019] [Revised: 05/20/2019] [Accepted: 06/18/2019] [Indexed: 12/21/2022]
Abstract
Women are more susceptible to various stress-linked psychopathologies, including depression. Dysfunction of the medial prefrontal cortex (mPFC) has been implicated in depression, and studies indicate sex differences in stress effects on mPFC structure and function. For example, chronic stress induces dendritic atrophy in the mPFC in male rats, yet dendritic growth in females. Recent findings suggest glial pathways toward depression. Glia are highly responsive to neuronal activity and function as critical regulators of synaptic plasticity. Preclinical models demonstrate stress-induced microglial activation in mPFC in males, yet deactivation in females. By contrast, stress reduces astrocyte complexity in mPFC in male rats, whereas the effects in females are unknown. Glia possess receptors for most gonadal hormones and gonadal hormones are known to modulate neuronal activity. Thus, gonadal hormones represent a potential mechanism underlying sex differences in glia, as well as divergent stress effects. Therefore, we examined the role of gonadal hormones in sex-specific stress effects on neuronal activity (ie FosB/ ΔFosB induction) and glia in the mPFC. The findings obtained indicate greater microglial activation in mPFC in females and a greater astrocyte area in males. Basal astrocyte morphology is modulated by androgens, whereas androgens or oestrogens dampen the microglial state in males. Astrocyte morphology is associated with neuronal activity in both sexes, regardless of hormonal condition. Chronic stress induced astrocytic atrophy in males, yet hypertrophy in females, with gonadal hormones partly regulating this difference. Stress effects on microglia are oestradiol-dependent in females. Taken together, these data suggest sex-specific, gonadal hormone-dependent stress effects on astrocytes and microglia in the mPFC.
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Affiliation(s)
- Justin L Bollinger
- Department of Psychological and Brain Sciences, Indiana University, Bloomington, IN, USA
- Program in Neuroscience, Indiana University, Bloomington, IN, USA
- Center for the Integrative Study of Animal Behavior, Indiana University, Bloomington, IN, USA
| | - Isabella Salinas
- Center for the Integrative Study of Animal Behavior, Indiana University, Bloomington, IN, USA
| | - Emily Fender
- Department of Psychological and Brain Sciences, Indiana University, Bloomington, IN, USA
| | - Dale R Sengelaub
- Department of Psychological and Brain Sciences, Indiana University, Bloomington, IN, USA
- Program in Neuroscience, Indiana University, Bloomington, IN, USA
- Center for the Integrative Study of Animal Behavior, Indiana University, Bloomington, IN, USA
| | - Cara L Wellman
- Department of Psychological and Brain Sciences, Indiana University, Bloomington, IN, USA
- Program in Neuroscience, Indiana University, Bloomington, IN, USA
- Center for the Integrative Study of Animal Behavior, Indiana University, Bloomington, IN, USA
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8
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Chew C, Sengelaub DR. Neuroprotective Effects of Exercise on the Morphology of Somatic Motoneurons Following the Death of Neighboring Motoneurons. Neurorehabil Neural Repair 2019; 33:656-667. [PMID: 31286830 DOI: 10.1177/1545968319860485] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Background. Motoneuron loss is a severe medical problem that can result in loss of motor control and eventually death. We have previously demonstrated that partial motoneuron loss can result in dendritic atrophy and functional deficits in nearby surviving motoneurons, and that treatment with androgens can be neuroprotective against this dendritic atrophy. Exercise has also been shown to be protective following a variety of neural injury models and, in some cases, is dependent on androgen action. Objective. In this study, we explored whether exercise shows the same neuroprotective effect on induced dendritic atrophy as that seen with androgen treatment. Methods. Motoneurons innervating the vastus medialis muscles of adult male rats were selectively killed by intramuscular injection of cholera toxin-conjugated saporin. Following saporin injections, some animals were allowed free access to a running wheel attached to their home cages. Four weeks later, motoneurons innervating the ipsilateral vastus lateralis muscle were labeled with cholera toxin-conjugated horseradish peroxidase, and dendritic arbors were reconstructed in 3 dimensions. Results. Dendritic arbor lengths of animals allowed to exercise were significantly longer than those not allowed to exercise. Conclusions. These findings indicate that exercise following neural injury exerts a protective effect on motoneuron dendrites comparable to that seen with exogenous androgen treatment.
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Affiliation(s)
- Cory Chew
- 1 Indiana University, Bloomington, IN, USA
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9
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Chew C, Kiley BJ, Sengelaub DR. Neuroprotective Effects on the Morphology of Somatic Motoneurons Following the Death of Neighboring Motoneurons: A Role for Microglia? Dev Neurobiol 2019; 79:131-154. [PMID: 30430756 DOI: 10.1002/dneu.22652] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2018] [Revised: 10/19/2018] [Accepted: 10/29/2018] [Indexed: 11/08/2022]
Abstract
Partial depletion of spinal motoneuron populations induces dendritic atrophy in neighboring motoneurons, and treatment with testosterone protects motoneurons from induced dendritic atrophy. We explored a potential mechanism for this induced atrophy and protection by testosterone, examining the microglial response to partial depletion of motoneurons. Motoneurons innervating the vastus medialis muscles of adult male rats were killed by intramuscular injection of cholera toxin-conjugated saporin; some saporin-injected rats were treated with testosterone. Microglia were later visualized via immunohistochemical staining, classified as monitoring or activated, and counted stereologically. Partial motoneuron depletion increased the number of activated microglia in the quadriceps motor pool, and this increase was attenuated with testosterone treatment. The attenuation in microglial response could reflect an effect of testosterone on suppressing microglia activation, potentially sparing motoneuron dendrites. Alternatively, testosterone could be neuroprotective, sparing motoneuron dendrites, secondarily resulting in reduced microglial activation. To discriminate between these hypotheses, following partial motoneuron depletion, rats were treated with minocycline to inhibit microglial activation. Motoneurons innervating the ipsilateral vastus lateralis muscle were later labeled with cholera toxin-conjugated horseradish peroxidase, and dendritic arbors were reconstructed. Reduction of microglial activation by minocycline did not prevent induced dendritic atrophy following partial motoneuron depletion. Further, reduction of microglial activation by minocycline treatment resulted in dendritic atrophy in intact animals. Together, these findings indicate that the neuroprotective effect of testosterone on dendrites following motoneuron death is not due to inhibiting microglial activation, and that microglial activity contributes to the normal maintenance of dendritic arbors.
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Affiliation(s)
- Cory Chew
- Program in Neuroscience and Department of Psychological and Brain Sciences, Indiana University, Bloomington, Indiana, 47405
| | - Brandon J Kiley
- Program in Neuroscience and Department of Psychological and Brain Sciences, Indiana University, Bloomington, Indiana, 47405
| | - Dale R Sengelaub
- Program in Neuroscience and Department of Psychological and Brain Sciences, Indiana University, Bloomington, Indiana, 47405
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Asih PR, Tegg ML, Sohrabi H, Carruthers M, Gandy SE, Saad F, Verdile G, Ittner LM, Martins RN. Multiple Mechanisms Linking Type 2 Diabetes and Alzheimer's Disease: Testosterone as a Modifier. J Alzheimers Dis 2018; 59:445-466. [PMID: 28655134 DOI: 10.3233/jad-161259] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Evidence in support of links between type-2 diabetes mellitus (T2DM) and Alzheimer's disease (AD) has increased considerably in recent years. AD pathological hallmarks include the accumulation of extracellular amyloid-β (Aβ) and intracellular hyperphosphorylated tau in the brain, which are hypothesized to promote inflammation, oxidative stress, and neuronal loss. T2DM exhibits many AD pathological features, including reduced brain insulin uptake, lipid dysregulation, inflammation, oxidative stress, and depression; T2DM has also been shown to increase AD risk, and with increasing age, the prevalence of both conditions increases. In addition, amylin deposition in the pancreas is more common in AD than in normal aging, and although there is no significant increase in cerebral Aβ deposition in T2DM, the extent of Aβ accumulation in AD correlates with T2DM duration. Given these similarities and correlations, there may be common underlying mechanism(s) that predispose to both T2DM and AD. In other studies, an age-related gradual loss of testosterone and an increase in testosterone resistance has been shown in men; low testosterone levels can also occur in women. In this review, we focus on the evidence for low testosterone levels contributing to an increased risk of T2DM and AD, and the potential of testosterone treatment in reducing this risk in both men and women. However, such testosterone treatment may need to be long-term, and would need regular monitoring to maintain testosterone at physiological levels. It is possible that a combination of testosterone therapy together with a healthy lifestyle approach, including improved diet and exercise, may significantly reduce AD risk.
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Affiliation(s)
- Prita R Asih
- Department of Anatomy, Dementia Research Unit, School of Medical Sciences, Faculty of Medicine, University of New South Wales, Sydney, NSW, Australia.,KaRa Institute of Neurological Diseases, Sydney, NSW, Australia
| | - Michelle L Tegg
- School of Medical and Health Sciences, Edith Cowan University, Perth, WA, Australia
| | - Hamid Sohrabi
- School of Medical and Health Sciences, Edith Cowan University, Perth, WA, Australia.,Australian Alzheimer's Research Foundation Perth, WA, Australia.,Department of Biomedical Sciences, Macquarie University, Sydney, NSW, Australia.,School of Psychiatry and Clinical Neurosciences, University of Western Australia, Perth, WA, Australia
| | | | - Samuel E Gandy
- Departments of Neurology and Psychiatry and the Alzheimer's Disease Research Center, Icahn School of Medicine at Mount Sinai, One Gustave L Levy Place, New York, NY, USA
| | - Farid Saad
- Bayer Pharma AG, Global Medical Affairs Andrology, Berlin, Germany.,Gulf Medical University School of Medicine, Ajman, UAE
| | - Giuseppe Verdile
- Australian Alzheimer's Research Foundation Perth, WA, Australia.,School of Biomedical Sciences, Curtin University of Technology, Bentley, WA, Australia
| | - Lars M Ittner
- Department of Anatomy, Dementia Research Unit, School of Medical Sciences, Faculty of Medicine, University of New South Wales, Sydney, NSW, Australia.,Neuroscience Research Australia, Sydney, NSW, Australia
| | - Ralph N Martins
- KaRa Institute of Neurological Diseases, Sydney, NSW, Australia.,School of Medical and Health Sciences, Edith Cowan University, Perth, WA, Australia.,Australian Alzheimer's Research Foundation Perth, WA, Australia.,Department of Biomedical Sciences, Macquarie University, Sydney, NSW, Australia.,School of Psychiatry and Clinical Neurosciences, University of Western Australia, Perth, WA, Australia
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11
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Insight into the neuroendocrine basis of signal evolution: a case study in foot-flagging frogs. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2017; 204:61-70. [DOI: 10.1007/s00359-017-1218-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2017] [Revised: 09/25/2017] [Accepted: 09/26/2017] [Indexed: 01/15/2023]
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12
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Cai Y, Chew C, Muñoz F, Sengelaub DR. Neuroprotective effects of testosterone metabolites and dependency on receptor action on the morphology of somatic motoneurons following the death of neighboring motoneurons. Dev Neurobiol 2016; 77:691-707. [PMID: 27569375 DOI: 10.1002/dneu.22445] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2016] [Revised: 08/23/2016] [Accepted: 08/25/2016] [Indexed: 11/11/2022]
Abstract
Partial depletion of spinal motoneuron populations induces dendritic atrophy in neighboring motoneurons, and treatment with testosterone is neuroprotective, attenuating induced dendritic atrophy. In this study we examined whether the protective effects of testosterone could be mediated via its androgenic or estrogenic metabolites. Furthermore, to assess whether these neuroprotective effects were mediated through steroid hormone receptors, we used receptor antagonists to attempt to prevent the neuroprotective effects of hormones after partial motoneuron depletion. Motoneurons innervating the vastus medialis muscles of adult male rats were selectively killed by intramuscular injection of cholera toxin-conjugated saporin. Simultaneously, some saporin-injected rats were treated with either dihydrotestosterone or estradiol, alone or in combination with their respective receptor antagonists, or left untreated. Four weeks later, motoneurons innervating the ipsilateral vastus lateralis muscle were labeled with cholera toxin-conjugated horseradish peroxidase, and dendritic arbors were reconstructed in three dimensions. Compared with intact normal animals, partial motoneuron depletion resulted in decreased dendritic length in remaining quadriceps motoneurons. Dendritic atrophy was attenuated with both dihydrotestosterone and estradiol treatment to a degree similar to that seen with testosterone, and attenuation of atrophy was prevented by receptor blockade. Together, these findings suggest that neuroprotective effects on motoneurons can be mediated by either androgenic or estrogenic hormones and require action via steroid hormone receptors, further supporting a role for hormones as neurotherapeutic agents in the injured nervous system. © 2016 Wiley Periodicals, Inc. Develop Neurobiol 77: 691-707, 2017.
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Affiliation(s)
- Yi Cai
- Program in Neuroscience and Department of Psychological and Brain Sciences, Indiana University, Bloomington, Indiana, 47405
| | - Cory Chew
- Program in Neuroscience and Department of Psychological and Brain Sciences, Indiana University, Bloomington, Indiana, 47405
| | - Fernando Muñoz
- Program in Neuroscience and Department of Psychological and Brain Sciences, Indiana University, Bloomington, Indiana, 47405
| | - Dale R Sengelaub
- Program in Neuroscience and Department of Psychological and Brain Sciences, Indiana University, Bloomington, Indiana, 47405
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Mangiamele LA, Fuxjager MJ, Schuppe ER, Taylor RS, Hödl W, Preininger D. Increased androgenic sensitivity in the hind limb muscular system marks the evolution of a derived gestural display. Proc Natl Acad Sci U S A 2016; 113:5664-9. [PMID: 27143723 PMCID: PMC4878525 DOI: 10.1073/pnas.1603329113] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Physical gestures are prominent features of many species' multimodal displays, yet how evolution incorporates body and leg movements into animal signaling repertoires is unclear. Androgenic hormones modulate the production of reproductive signals and sexual motor skills in many vertebrates; therefore, one possibility is that selection for physical signals drives the evolution of androgenic sensitivity in select neuromotor pathways. We examined this issue in the Bornean rock frog (Staurois parvus, family: Ranidae). Males court females and compete with rivals by performing both vocalizations and hind limb gestural signals, called "foot flags." Foot flagging is a derived display that emerged in the ranids after vocal signaling. Here, we show that administration of testosterone (T) increases foot flagging behavior under seminatural conditions. Moreover, using quantitative PCR, we also find that adult male S. parvus maintain a unique androgenic phenotype, in which androgen receptor (AR) in the hind limb musculature is expressed at levels ∼10× greater than in two other anuran species, which do not produce foot flags (Rana pipiens and Xenopus laevis). Finally, because males of all three of these species solicit mates with calls, we accordingly detect no differences in AR expression in the vocal apparatus (larynx) among taxa. The results show that foot flagging is an androgen-dependent gestural signal, and its emergence is associated with increased androgenic sensitivity within the hind limb musculature. Selection for this novel gestural signal may therefore drive the evolution of increased AR expression in key muscles that control signal production to support adaptive motor performance.
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Affiliation(s)
- Lisa A Mangiamele
- Department of Biological Sciences, Smith College, Northampton, MA 01063
| | | | - Eric R Schuppe
- Department of Biology, Wake Forest University, Winston-Salem, NC 27109
| | - Rebecca S Taylor
- Department of Biological Sciences, Smith College, Northampton, MA 01063
| | - Walter Hödl
- Department of Integrative Zoology, University of Vienna, A-1090 Vienna, Austria
| | - Doris Preininger
- Department of Integrative Zoology, University of Vienna, A-1090 Vienna, Austria; Vienna Zoo, A-1130 Vienna, Austria
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Fuxjager MJ, Lee JH, Chan TM, Bahn JH, Chew JG, Xiao X, Schlinger BA. Research Resource: Hormones, Genes, and Athleticism: Effect of Androgens on the Avian Muscular Transcriptome. Mol Endocrinol 2016; 30:254-71. [PMID: 26745669 DOI: 10.1210/me.2015-1270] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Male vertebrate social displays vary from physically simple to complex, with the latter involving exquisite motor command of the body and appendages. Studies of these displays have, in turn, provided substantial insight into neuromotor mechanisms. The neotropical golden-collared manakin (Manacus vitellinus) has been used previously as a model to investigate intricate motor skills because adult males of this species perform an acrobatic and androgen-dependent courtship display. To support this behavior, these birds express elevated levels of androgen receptors (AR) in their skeletal muscles. Here we use RNA sequencing to explore how testosterone (T) modulates the muscular transcriptome to support male manakin courtship displays. In addition, we explore how androgens influence gene expression in the muscles of the zebra finch (Taenopygia guttata), a model passerine bird with a limited courtship display and minimal muscle AR. We identify androgen-dependent, muscle-specific gene regulation in both species. In addition, we identify manakin-specific effects that are linked to muscle use during the manakin display, including androgenic regulation of genes associated with muscle fiber contractility, cellular homeostasis, and energetic efficiency. Overall, our results point to numerous genes and gene networks impacted by androgens in male birds, including some that underlie optimal muscle function necessary for performing acrobatic display routines. Manakins are excellent models to explore gene regulation promoting athletic ability.
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Affiliation(s)
- Matthew J Fuxjager
- Department of Biology (M.J.F.), Wake Forest University, Winston-Salem, North Carolina 27109; Department of Life and Nanopharmaceutical Sciences (J.-H.L.), and Department of Maxillofacial Biomedical Engineering (J.-H.L.), School of Dentistry, Kyung Hee University, Dongdaemun-gu, Seoul 130-701, Republic of Korea; Department of Integrative Biology and Physiology (M.J.F., J.-H.L., T.-M.C., J.H.B., J.G.C., X.X., B.A.S.) and Laboratory of Neuroendocrinology (M.J.F., B.A.S.), Brain Research Institute, University of California, Los Angeles, Los Angeles, California 90095; and Smithsonian Tropical Research Institute (B.A.S.), 0843-03092 Balboa, Ancón, Panama
| | - Jae-Hyung Lee
- Department of Biology (M.J.F.), Wake Forest University, Winston-Salem, North Carolina 27109; Department of Life and Nanopharmaceutical Sciences (J.-H.L.), and Department of Maxillofacial Biomedical Engineering (J.-H.L.), School of Dentistry, Kyung Hee University, Dongdaemun-gu, Seoul 130-701, Republic of Korea; Department of Integrative Biology and Physiology (M.J.F., J.-H.L., T.-M.C., J.H.B., J.G.C., X.X., B.A.S.) and Laboratory of Neuroendocrinology (M.J.F., B.A.S.), Brain Research Institute, University of California, Los Angeles, Los Angeles, California 90095; and Smithsonian Tropical Research Institute (B.A.S.), 0843-03092 Balboa, Ancón, Panama
| | - Tak-Ming Chan
- Department of Biology (M.J.F.), Wake Forest University, Winston-Salem, North Carolina 27109; Department of Life and Nanopharmaceutical Sciences (J.-H.L.), and Department of Maxillofacial Biomedical Engineering (J.-H.L.), School of Dentistry, Kyung Hee University, Dongdaemun-gu, Seoul 130-701, Republic of Korea; Department of Integrative Biology and Physiology (M.J.F., J.-H.L., T.-M.C., J.H.B., J.G.C., X.X., B.A.S.) and Laboratory of Neuroendocrinology (M.J.F., B.A.S.), Brain Research Institute, University of California, Los Angeles, Los Angeles, California 90095; and Smithsonian Tropical Research Institute (B.A.S.), 0843-03092 Balboa, Ancón, Panama
| | - Jae Hoon Bahn
- Department of Biology (M.J.F.), Wake Forest University, Winston-Salem, North Carolina 27109; Department of Life and Nanopharmaceutical Sciences (J.-H.L.), and Department of Maxillofacial Biomedical Engineering (J.-H.L.), School of Dentistry, Kyung Hee University, Dongdaemun-gu, Seoul 130-701, Republic of Korea; Department of Integrative Biology and Physiology (M.J.F., J.-H.L., T.-M.C., J.H.B., J.G.C., X.X., B.A.S.) and Laboratory of Neuroendocrinology (M.J.F., B.A.S.), Brain Research Institute, University of California, Los Angeles, Los Angeles, California 90095; and Smithsonian Tropical Research Institute (B.A.S.), 0843-03092 Balboa, Ancón, Panama
| | - Jenifer G Chew
- Department of Biology (M.J.F.), Wake Forest University, Winston-Salem, North Carolina 27109; Department of Life and Nanopharmaceutical Sciences (J.-H.L.), and Department of Maxillofacial Biomedical Engineering (J.-H.L.), School of Dentistry, Kyung Hee University, Dongdaemun-gu, Seoul 130-701, Republic of Korea; Department of Integrative Biology and Physiology (M.J.F., J.-H.L., T.-M.C., J.H.B., J.G.C., X.X., B.A.S.) and Laboratory of Neuroendocrinology (M.J.F., B.A.S.), Brain Research Institute, University of California, Los Angeles, Los Angeles, California 90095; and Smithsonian Tropical Research Institute (B.A.S.), 0843-03092 Balboa, Ancón, Panama
| | - Xinshu Xiao
- Department of Biology (M.J.F.), Wake Forest University, Winston-Salem, North Carolina 27109; Department of Life and Nanopharmaceutical Sciences (J.-H.L.), and Department of Maxillofacial Biomedical Engineering (J.-H.L.), School of Dentistry, Kyung Hee University, Dongdaemun-gu, Seoul 130-701, Republic of Korea; Department of Integrative Biology and Physiology (M.J.F., J.-H.L., T.-M.C., J.H.B., J.G.C., X.X., B.A.S.) and Laboratory of Neuroendocrinology (M.J.F., B.A.S.), Brain Research Institute, University of California, Los Angeles, Los Angeles, California 90095; and Smithsonian Tropical Research Institute (B.A.S.), 0843-03092 Balboa, Ancón, Panama
| | - Barney A Schlinger
- Department of Biology (M.J.F.), Wake Forest University, Winston-Salem, North Carolina 27109; Department of Life and Nanopharmaceutical Sciences (J.-H.L.), and Department of Maxillofacial Biomedical Engineering (J.-H.L.), School of Dentistry, Kyung Hee University, Dongdaemun-gu, Seoul 130-701, Republic of Korea; Department of Integrative Biology and Physiology (M.J.F., J.-H.L., T.-M.C., J.H.B., J.G.C., X.X., B.A.S.) and Laboratory of Neuroendocrinology (M.J.F., B.A.S.), Brain Research Institute, University of California, Los Angeles, Los Angeles, California 90095; and Smithsonian Tropical Research Institute (B.A.S.), 0843-03092 Balboa, Ancón, Panama
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English AW, Wilhelm JC, Ward PJ. Exercise, neurotrophins, and axon regeneration in the PNS. Physiology (Bethesda) 2015; 29:437-45. [PMID: 25362637 DOI: 10.1152/physiol.00028.2014] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Electrical stimulation and exercise are treatments to enhance recovery from peripheral nerve injuries. Brain-derived neurotrophic factor and androgen receptor signaling are requirements for the effectiveness of these treatments. Increased neuronal activity is adequate to promote regeneration in injured nerves, but the dosing of activity and its relationship to neurotrophins and sex steroid hormones is less clear. Translation of these therapies will require principles associated with their cellular mechanisms.
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Affiliation(s)
- Arthur W English
- Department of Cell Biology, Emory University School of Medicine, Atlanta, Georgia; and
| | - Jennifer C Wilhelm
- Department of Psychology, College of Charleston, Charleston, South Carolina
| | - Patricia J Ward
- Department of Cell Biology, Emory University School of Medicine, Atlanta, Georgia; and
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Rudolph LM, Sengelaub DR. Castration-induced upregulation of muscle ERα supports estrogen sensitivity of motoneuron dendrites in a sexually dimorphic neuromuscular system. Dev Neurobiol 2013; 73:921-35. [PMID: 23939785 DOI: 10.1002/dneu.22118] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2013] [Revised: 07/31/2013] [Accepted: 08/02/2013] [Indexed: 01/21/2023]
Abstract
The spinal cord of rats contains the sexually dimorphic motoneurons of the spinal nucleus of the bulbocavernosus (SNB). In males, SNB dendrites fail to grow after castration, but androgen or estrogen treatment supports dendritic growth in castrated males. Estrogenic support of SNB dendrite growth is mediated by estrogen receptors (ER) in the target muscle. ERα expression in cells lacking a basal lamina (referred to as "extra-muscle fiber cells") of the SNB target musculature coincides with the period of estrogen-dependent SNB dendrite growth. In the SNB target muscle, extra-muscle fiber ERα expression declines with age and is typically absent after postnatal (P) day 21 (P21). Given that estradiol downregulates ERα in skeletal muscle, we tested the hypothesis that depleting gonadal hormones would prevent the postnatal decline in ERα expression in the SNB target musculature. We castrated male rats at P7 and assessed ERα immunolabeling at P21; ERα expression was significantly greater in castrated males compared with normal animals. Because ERα expression in SNB target muscles mediates estrogen-dependent SNB dendrogenesis, we further hypothesized that the castration-induced increase in muscle ERα would heighten the estrogen sensitivity of SNB dendrites. Male rats were castrated at P7 and treated with estradiol from P21 to P28; estradiol treatment in castrates resulted in dendritic hypertrophy in SNB motoneurons compared with normal males. We conclude that early castration results in an increase in ERα expression in the SNB target muscle, and this upregulation of ERα supports estrogen sensitivity of SNB dendrites, allowing for hypermasculinization of SNB dendritic arbors.
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Affiliation(s)
- Lauren M Rudolph
- Department of Psychological and Brain Sciences and Program in Neuroscience, Indiana University, Bloomington, Indiana, 47405
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