1
|
Bjornson KJ, Vanderplow AM, Yang Y, Anderson DR, Kermath BA, Cahill ME. Stress-mediated dysregulation of the Rap1 small GTPase impairs hippocampal structure and function. iScience 2023; 26:107566. [PMID: 37664580 PMCID: PMC10470260 DOI: 10.1016/j.isci.2023.107566] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2022] [Revised: 05/15/2023] [Accepted: 08/02/2023] [Indexed: 09/05/2023] Open
Abstract
The effects of repeated stress on cognitive impairment are thought to be mediated, at least in part, by reductions in the stability of dendritic spines in brain regions critical for proper learning and memory, including the hippocampus. Small GTPases are particularly potent regulators of dendritic spine formation, stability, and morphology in hippocampal neurons. Through the use of small GTPase protein profiling in mice, we identify increased levels of synaptic Rap1 in the hippocampal CA3 region in response to escalating, intermittent stress. We then demonstrate that increased Rap1 in the CA3 is sufficient in and of itself to produce stress-relevant dendritic spine and cognitive phenotypes. Further, using super-resolution imaging, we investigate how the pattern of Rap1 trafficking to synapses likely underlies its effects on the stability of select dendritic spine subtypes. These findings illuminate the involvement of aberrant Rap1 regulation in the hippocampus in contributing to the psychobiological effects of stress.
Collapse
Affiliation(s)
- Kathryn J. Bjornson
- Department of Comparative Biosciences, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Amanda M. Vanderplow
- Department of Comparative Biosciences, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Yezi Yang
- Department of Comparative Biosciences, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Danielle R. Anderson
- Department of Comparative Biosciences, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Bailey A. Kermath
- Department of Comparative Biosciences, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Michael E. Cahill
- Department of Comparative Biosciences, University of Wisconsin-Madison, Madison, WI 53706, USA
| |
Collapse
|
2
|
Vanderplow AM, Kermath BA, Bernhardt CR, Gums KT, Seablom EN, Radcliff AB, Ewald AC, Jones MV, Baker TL, Watters JJ, Cahill ME. A feature of maternal sleep apnea during gestation causes autism-relevant neuronal and behavioral phenotypes in offspring. PLoS Biol 2022; 20:e3001502. [PMID: 35113852 PMCID: PMC8812875 DOI: 10.1371/journal.pbio.3001502] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2021] [Accepted: 11/29/2021] [Indexed: 12/26/2022] Open
Abstract
Mounting epidemiologic and scientific evidence indicates that many psychiatric disorders originate from a complex interplay between genetics and early life experiences, particularly in the womb. Despite decades of research, our understanding of the precise prenatal and perinatal experiences that increase susceptibility to neurodevelopmental disorders remains incomplete. Sleep apnea (SA) is increasingly common during pregnancy and is characterized by recurrent partial or complete cessations in breathing during sleep. SA causes pathological drops in blood oxygen levels (intermittent hypoxia, IH), often hundreds of times each night. Although SA is known to cause adverse pregnancy and neonatal outcomes, the long-term consequences of maternal SA during pregnancy on brain-based behavioral outcomes and associated neuronal functioning in the offspring remain unknown. We developed a rat model of maternal SA during pregnancy by exposing dams to IH, a hallmark feature of SA, during gestational days 10 to 21 and investigated the consequences on the offspring's forebrain synaptic structure, synaptic function, and behavioral phenotypes across multiples stages of development. Our findings represent a rare example of prenatal factors causing sexually dimorphic behavioral phenotypes associated with excessive (rather than reduced) synapse numbers and implicate hyperactivity of the mammalian target of rapamycin (mTOR) pathway in contributing to the behavioral aberrations. These findings have implications for neuropsychiatric disorders typified by superfluous synapse maintenance that are believed to result, at least in part, from largely unknown insults to the maternal environment.
Collapse
Affiliation(s)
- Amanda M. Vanderplow
- Department of Comparative Biosciences, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Bailey A. Kermath
- Department of Comparative Biosciences, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Cassandra R. Bernhardt
- Department of Comparative Biosciences, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Kimberly T. Gums
- Department of Comparative Biosciences, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Erin N. Seablom
- Department of Comparative Biosciences, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Abigail B. Radcliff
- Department of Comparative Biosciences, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Andrea C. Ewald
- Department of Comparative Biosciences, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Mathew V. Jones
- Department of Neuroscience, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Tracy L. Baker
- Department of Comparative Biosciences, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Jyoti J. Watters
- Department of Comparative Biosciences, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Michael E. Cahill
- Department of Comparative Biosciences, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| |
Collapse
|
3
|
Vanderplow AM, Eagle AL, Kermath BA, Bjornson KJ, Robison AJ, Cahill ME. Akt-mTOR hypoactivity in bipolar disorder gives rise to cognitive impairments associated with altered neuronal structure and function. Neuron 2021; 109:1479-1496.e6. [PMID: 33765445 PMCID: PMC8105282 DOI: 10.1016/j.neuron.2021.03.008] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Revised: 01/20/2021] [Accepted: 03/04/2021] [Indexed: 12/22/2022]
Abstract
The Akt family of kinases exerts many of its cellular effects via the activation of the mammalian target of rapamycin (mTOR) kinase through a series of intermediary proteins. Multiple lines of evidence have identified Akt-family kinases as candidate schizophrenia and bipolar disorder genes. Although dysfunction of the prefrontal cortex (PFC) is a key feature of both schizophrenia and bipolar disorder, no studies have comprehensively assessed potential alterations in Akt-mTOR pathway activity in the PFC of either disorder. Here, we examined the activity and expression profile of key proteins in the Akt-mTOR pathway in bipolar disorder and schizophrenia homogenates from two different PFC subregions. Our findings identify reduced Akt-mTOR PFC signaling in a subset of bipolar disorder subjects. Using a reverse-translational approach, we demonstrated that Akt hypofunction in the PFC is sufficient to give rise to key cognitive phenotypes that are paralleled by alterations in synaptic connectivity and function.
Collapse
Affiliation(s)
- Amanda M Vanderplow
- Department of Comparative Biosciences, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Andrew L Eagle
- Department of Physiology, Michigan State University, East Lansing, MI 48824, USA
| | - Bailey A Kermath
- Department of Comparative Biosciences, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Kathryn J Bjornson
- Department of Comparative Biosciences, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Alfred J Robison
- Department of Physiology, Michigan State University, East Lansing, MI 48824, USA
| | - Michael E Cahill
- Department of Comparative Biosciences, University of Wisconsin-Madison, Madison, WI 53706, USA.
| |
Collapse
|
4
|
Kermath BA, Vanderplow AM, Cahill ME. Dysregulated Prefrontal Cortical RhoA Signal Transduction in Bipolar Disorder with Psychosis: New Implications for Disease Pathophysiology. Cereb Cortex 2021; 30:59-71. [PMID: 31220216 DOI: 10.1093/cercor/bhz070] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
While research has identified alterations in dorsolateral prefrontal cortical function as a key factor to the etiology of bipolar disorder, few studies have uncovered robust changes in protein signal transduction pathways in this disorder. Given the direct relevance of protein-based expressional alterations to cellular functions and because many of the key regulatory mechanisms for the disease pathogenesis likely include alterations in protein activity rather than changes in expression alone, the identification of alterations in discrete signal transduction pathways in bipolar disorder would have broad implications for understanding the disease pathophysiology. As prior microarray data point to a previously unrecognized involvement of the RhoA network in bipolar disorder, here we investigate the protein expression and activity of key components of a RhoA signal transduction pathway in dorsolateral prefrontal cortical homogenates from subjects with bipolar disorder. The results of this investigation implicate overactivation of prefrontal cortical RhoA signaling in specific subtypes of bipolar disorder. The specificity of these findings is demonstrated by a lack of comparable changes in schizophrenia; however, our findings do identify convergence between both disorders at the level of activity-mediated actin cytoskeletal regulation. These findings have implications for understanding the altered cortical synaptic connectivity of bipolar disorder.
Collapse
Affiliation(s)
- Bailey A Kermath
- Department of Comparative Biosciences, University of Wisconsin at Madison, Madison, WI, USA
| | - Amanda M Vanderplow
- Department of Comparative Biosciences, University of Wisconsin at Madison, Madison, WI, USA
| | - Michael E Cahill
- Department of Comparative Biosciences, University of Wisconsin at Madison, Madison, WI, USA
| |
Collapse
|
5
|
Vanderplow AM, Kermath BA, Ewald AC, Gums KT, Seablom EN, Baker TL, Watters JJ, Cahill ME. Maternal sleep disordered breathing during pregnancy as a cause of autism relevant neuronal and behavioral aberrations in the offspring. FASEB J 2020. [DOI: 10.1096/fasebj.2020.34.s1.02352] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
|
6
|
Roby DA, Ruiz F, Kermath BA, Voorhees JR, Niehoff M, Zhang J, Morley JE, Musiek ES, Farr SA, Burris TP. Pharmacological activation of the nuclear receptor REV-ERB reverses cognitive deficits and reduces amyloid-β burden in a mouse model of Alzheimer's disease. PLoS One 2019; 14:e0215004. [PMID: 30973894 PMCID: PMC6459530 DOI: 10.1371/journal.pone.0215004] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2018] [Accepted: 03/26/2019] [Indexed: 12/27/2022] Open
Abstract
Alzheimer's disease currently lacks treatment options that effectively reverse the biological/anatomical pathology and cognitive deficits associated with the disease. Loss of function of the nuclear receptor REV-ERB is associated with reduced cognitive function in mouse models. The effect of enhanced REV-ERB activity on cognitive function has not been examined. In this study, we tested the hypothesis that enhanced REV-ERB function may enhance cognitive function in a model of Alzheimer's disease. We utilized the REV-ERB agonist SR9009 to pharmacologically activate the activity of REV-ERB in the SAMP8 mouse model of Alzheimer's disease. SR9009 reversed cognitive dysfunction of an aged SAMP8 mouse in several behavioral assays including novel object recognition, T-maze foot shock avoidance, and lever press operant conditioning task assessments. SR9009 treatment reduced amyloid-β 1-40 and 1-42 levels in the cortex, which is consistent with improved cognitive function. Furthermore, SR9009 treatment led to increased hippocampal PSD-95, cortical synaptophysin expression and the number of synapses suggesting improvement in synaptic function. We conclude that REV-ERB is a potential target for treatment of Alzheimer's disease.
Collapse
Affiliation(s)
- Deborah A. Roby
- Department of Pharmacology and Physiology, Saint Louis University School of Medicine, St. Louis, MO, United States of America
| | - Fernanda Ruiz
- Department of Pharmacology and Physiology, Saint Louis University School of Medicine, St. Louis, MO, United States of America
| | - Bailey A. Kermath
- Department of Pharmacology and Physiology, Saint Louis University School of Medicine, St. Louis, MO, United States of America
| | - Jaymie R. Voorhees
- Center for Clinical Pharmacology, Washington University School of Medicine and St. Louis College of Pharmacy, St. Louis, MO, United States of America
| | - Michael Niehoff
- Department of Internal Medicine, Saint Louis University School of Medicine, St. Louis, MO, United States of America
| | - Jinsong Zhang
- Department of Pharmacology and Physiology, Saint Louis University School of Medicine, St. Louis, MO, United States of America
| | - John E. Morley
- Department of Internal Medicine, Saint Louis University School of Medicine, St. Louis, MO, United States of America
| | - Erik S. Musiek
- Department of Neurology, Washington University School of Medicine, St. Louis, MO, United States of America
| | - Susan A. Farr
- Department of Pharmacology and Physiology, Saint Louis University School of Medicine, St. Louis, MO, United States of America
- Department of Internal Medicine, Saint Louis University School of Medicine, St. Louis, MO, United States of America
| | - Thomas P. Burris
- Center for Clinical Pharmacology, Washington University School of Medicine and St. Louis College of Pharmacy, St. Louis, MO, United States of America
| |
Collapse
|
7
|
Abstract
The role of the hypothalamus in female reproductive senescence is unclear. Here we identified novel molecular neuroendocrine changes during the natural progression from regular reproductive cycles to acyclicity in middle-aged female rats, comparable with the perimenopausal progression in women. Expression of 48 neuroendocrine genes was quantified within three hypothalamic regions: the anteroventral periventricular nucleus, the site of steroid positive feedback onto GnRH neurons; the arcuate nucleus (ARC), the site of negative feedback and pulsatile GnRH release; and the median eminence (ME), the site of GnRH secretion. Surprisingly, the majority of changes occurred in the ARC and ME, with few effects in anteroventral periventricular nucleus. The overall pattern was increased mRNA levels with chronological age and decreases with reproductive cycle status in middle-aged rats. Affected genes included transcription factors (Stat5b, Arnt, Ahr), sex steroid hormone receptors (Esr1, Esr2, Pgr, Ar), steroidogenic enzymes (Sts, Hsd17b8), growth factors (Igf1, Tgfa), and neuropeptides (Kiss1, Tac2, Gnrh1). Bionetwork analysis revealed region-specific correlations between genes and hormones. Immunohistochemical analyses of kisspeptin and estrogen receptor-α in the ARC demonstrated age-related decreases in kisspeptin cell numbers as well as kisspeptin-estrogen receptor-α dual-labeled cells. Taken together, these results identify unexpectedly strong roles for the ME and ARC during reproductive decline and highlight fundamental differences between middle-aged rats with regular cycles and all other groups. Our data provide evidence of decreased excitatory stimulation and altered hormone feedback with aging and suggest novel neuroendocrine pathways that warrant future study. Furthermore, these changes may impact other neuroendocrine systems that undergo functional declines with age.
Collapse
Affiliation(s)
- Bailey A Kermath
- Institute for Neuroscience (B.A.K., A.C.G.), Division of Pharmacology and Toxicology (P.D.R., A.C.G.), and Institute for Cell and Molecular Biology (A.C.G.), The University of Texas at Austin, Austin, Texas 78712; Department of Biology (M.J.W.), University of Wisconsin-Whitewater, Whitewater, Wisconsin 53190; and Department of Pediatrics (A.W.), Johns Hopkins University School of Medicine, Baltimore Maryland 21287
| | | | | | | | | |
Collapse
|
8
|
Kermath BA, Riha PD, Sajjad A, Gore AC. Effects of chronic NMDA-NR2b inhibition in the median eminence of the reproductive senescent female rat. J Neuroendocrinol 2013; 25:887-97. [PMID: 23957788 PMCID: PMC3800684 DOI: 10.1111/jne.12087] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/14/2013] [Revised: 08/05/2013] [Accepted: 08/10/2013] [Indexed: 01/07/2023]
Abstract
Gonadotrophin-releasing hormone (GnRH) neurones of the hypothalamic-pituitary-gonadal (HPG) axis drive reproductive function and undergo age-related decreases in activation during the transition to reproductive senescence. Decreased GnRH secretion from the median eminence (ME) partially arises from attenuated glutamatergic signalling via the NMDA receptor (NMDAR) and may be a result of changing NMDAR stoichiometry to favour NR2b over NR2a subunit expression with ageing. We have previously shown that the systemic inhibition of NR2b-containing receptors with ifenprodil, an NR2b-specific antagonist, stimulates parameters of luteinising hormone (used as a proxy for GnRH) release in both young and middle-aged females. In the present study, we chronically administered ifenprodil, an NR2b-specific antagonist, at the site of GnRH terminals in the ME or at GnRH perikarya in the preoptic area, in reproductively senescent middle-aged female rats, aiming to determine whether NR2b antagonism could restore aspects of reproductive functionality. Effects on oestrous cyclicity, serum hormones, and protein expression of GnRH, NR2b and phosphorylated NR2b (Tyr-1472) in the ME were measured. Chronic ifenprodil treatment in the ME (but not the preoptic area) altered oestrous cyclicity by increasing the percentage of days spent in pro-oestrus. This was accompanied by increased GnRH fluorescence intensity in the external ME zone and a greater proportion of GnRH terminals that co-labelled with pNR2b with treatment. We also observed changes in the relationships between protein immunofluorescence, serum hormone levels and other aspects of reproductive physiology in acyclic females, as revealed by bionetwork analysis. Together, these data support the hypothesis that NMDAR-NR2b expression and phosphorylation state play a role in reproductive senescence and highlight the ME as a major player in reproductive ageing.
Collapse
Affiliation(s)
- Bailey A. Kermath
- Institute for Neuroscience, The University of Texas at Austin, Austin TX 78712 USA
| | - Penny D. Riha
- Division of Pharmacology and Toxicology, The University of Texas at Austin, Austin, TX 78712 USA.F
| | - Ahmar Sajjad
- Institute for Cell and Molecular Biology, The University of Texas at Austin, Austin, TX 78712 USA
| | - Andrea C. Gore
- Institute for Neuroscience, The University of Texas at Austin, Austin TX 78712 USA
- Division of Pharmacology and Toxicology, The University of Texas at Austin, Austin, TX 78712 USA.F
- Institute for Cell and Molecular Biology, The University of Texas at Austin, Austin, TX 78712 USA
- Corresponding author: Andrea C. Gore, The University of Texas at Austin, 107 W. Dean Keeton, C0875, Austin, TX 78712, Phone (512) 471-3669, Fax (512) 471-5002,
| |
Collapse
|
9
|
Abstract
Polychlorinated biphenyls (PCBs) are industrial contaminants and known endocrine-disrupting chemicals. Previous work has shown that gestational exposure to PCBs cause changes in reproductive neuroendocrine processes. Here we extended work farther down the life spectrum and tested the hypothesis that early life exposure to Aroclor 1221 (A1221), a mixture of primarily estrogenic PCBs, results in sexually dimorphic aging-associated alterations to reproductive parameters in rats, and gene expression changes in hypothalamic nuclei that regulate reproductive function. Pregnant Sprague Dawley rats were injected on gestational days 16 and 18 with vehicle (dimethylsulfoxide), A1221 (1 mg/kg), or estradiol benzoate (50 μg/kg). Developmental parameters, estrous cyclicity (females), and timing of reproductive senescence were monitored in the offspring through 9 months of age. Expression of 48 genes was measured in 3 hypothalamic nuclei: the anteroventral periventricular nucleus (AVPV), arcuate nucleus (ARC), and median eminence (females only) by real-time RT-PCR. Serum LH, testosterone, and estradiol were assayed in the same animals. In males, A1221 had no effects; however, prenatal estradiol benzoate increased serum estradiol, gene expression in the AVPV (1 gene), and ARC (2 genes) compared with controls. In females, estrous cycles were longer in the A1221-exposed females throughout the life cycle. Gene expression was not affected in the AVPV, but significant changes were caused by A1221 in the ARC and median eminence as a function of cycling status. Bionetwork analysis demonstrated fundamental differences in physiology and gene expression between cycling and acyclic females independent of treatment. Thus, gestational exposure to biologically relevant levels of estrogenic endocrine-disrupting chemicals has sexually dimorphic effects, with an altered transition to reproductive aging in female rats but relatively little effect in males.
Collapse
Affiliation(s)
- Deena M Walker
- The University of Texas at Austin, The Institute for Neuroscience, 1 University Station, C0875, Austin, Texas 78712, USA
| | | | | | | |
Collapse
|
10
|
Kermath BA, Gore AC. Neuroendocrine control of the transition to reproductive senescence: lessons learned from the female rodent model. Neuroendocrinology 2012; 96:1-12. [PMID: 22354218 PMCID: PMC3574559 DOI: 10.1159/000335994] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/15/2011] [Accepted: 12/06/2011] [Indexed: 01/19/2023]
Abstract
The natural transition to reproductive senescence is an important physiological process that occurs with aging, resulting in menopause in women and diminished or lost fertility in most mammalian species. This review focuses on how rodent models have informed our knowledge of age-related changes in gonadotropin-releasing hormone (GnRH) neurosecretory function and the subsequent loss of reproductive capacity. Studies in rats and mice have shown molecular, morphological and functional changes in GnRH cells. Furthermore, during reproductive aging altered sex steroid feedback to the hypothalamus contributes to a decrease of stimulatory signaling and increase in inhibitory tone onto GnRH neurons. At the site of the GnRH terminals where the peptide is released into the portal vasculature, the cytoarchitecture of the median eminence becomes disorganized with aging, and mechanisms of glial-GnRH neuronal communication may be disrupted. These changes can result in the dysregulation of GnRH secretion with reproductive decline. Interestingly, reproductive aging effects on the GnRH circuitry are observed in middle age even prior to any obvious physiological changes in cyclicity. We speculate that the hypothalamus may play a critical role in this mid-life transition. Because there are substantial species differences in these aging processes, we also compare and contrast rodent aging to that in primates. Work discussed herein shows that in order to understand neuroendocrine mechanisms of reproductive senescence, further research needs to be conducted in ovarian-intact models.
Collapse
Affiliation(s)
- Bailey A. Kermath
- Institute for Neurosciences; The University of Texas at Austin, Austin, TX, 78712, USA
| | - Andrea C. Gore
- Institute for Neurosciences; The University of Texas at Austin, Austin, TX, 78712, USA
- Division of Pharmacology & Toxicology; The University of Texas at Austin, Austin, TX, 78712, USA
- Institute for Cellular & Molecular Biology; The University of Texas at Austin, Austin, TX, 78712, USA
| |
Collapse
|
11
|
Rojas JC, Simola N, Kermath BA, Kane JR, Schallert T, Gonzalez-Lima F. Striatal neuroprotection with methylene blue. Neuroscience 2009; 163:877-89. [PMID: 19596056 DOI: 10.1016/j.neuroscience.2009.07.012] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2009] [Revised: 07/03/2009] [Accepted: 07/07/2009] [Indexed: 12/31/2022]
Abstract
Recent literature indicates that low-dose Methylene Blue (MB), an autoxidizable dye with powerful antioxidant and metabolic enhancing properties, might prevent neurotoxin-induced neural damage and associated functional deficits. This study evaluated whether local MB may counteract the anatomical and functional effects of the intrastriatal infusion of the neurotoxin rotenone (Rot) in the rat. To this end, stereological analyses of striatal lesion volumes were performed and changes in oxidative energy metabolism in the striatum and related motor regions were mapped using cytochrome oxidase histochemistry. The influence of MB on striatal levels of oxidative stress induced by Rot was determined, and behavioral tests were used to investigate the effect of unilateral MB coadministration on motor asymmetry. Rot induced large anatomical lesions resembling "metabolic strokes," whose size was greatly reduced in MB-treated rats. Moreover, MB prevented the decrease in cytochrome oxidase activity and the perilesional increase in oxidative stress associated with Rot infusion in the striatum. MB also prevented the indirect effects of the Rot-induced lesion on cytochrome oxidase activity in related motor regions, such as the striatal regions rostral and caudal to the lesion, the substantia nigra compacta and reticulata, and the pedunculopontine nucleus. At a network level, MB maintained a global strengthening of functional connectivity in basal ganglia-thalamocortical motor circuits, as opposed to the functional decoupling observed in Rot-alone subjects. Finally, MB partially prevented the behavioral sensorimotor asymmetries elicited by Rot. These results are consistent with protective effects of MB against neurotoxic damage in the brain parenchyma. This study provides the first demonstration of the anatomical, metabolic and behavioral neuroprotective effects of MB in the striatum in vivo, and supports the notion that MB could be a valuable intervention against neural damage associated with oxidative stress and energy hypometabolism.
Collapse
Affiliation(s)
- J C Rojas
- Institute for Neuroscience, University of Texas at Austin, Austin, TX, USA
| | | | | | | | | | | |
Collapse
|