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1.
Proc Natl Acad Sci U S A ; 116(43): 21800-21811, 2019 10 22.
Article in English | MEDLINE | ID: mdl-31591195

ABSTRACT

The excitatory amino acid transporter 2 (EAAT2) is the major glutamate transporter in the brain expressed predominantly in astrocytes and at low levels in neurons and axonal terminals. EAAT2 expression is reduced in aging and sporadic Alzheimer's disease (AD) patients' brains. The role EAAT2 plays in cognitive aging and its associated mechanisms remains largely unknown. Here, we show that conditional deletion of astrocytic and neuronal EAAT2 results in age-related cognitive deficits. Astrocytic, but not neuronal EAAT2, deletion leads to early deficits in short-term memory and in spatial reference learning and long-term memory. Neuronal EAAT2 loss results in late-onset spatial reference long-term memory deficit. Neuronal EAAT2 deletion leads to dysregulation of the kynurenine pathway, and astrocytic EAAT2 deficiency results in dysfunction of innate and adaptive immune pathways, which correlate with cognitive decline. Astrocytic EAAT2 deficiency also shows transcriptomic overlaps with human aging and AD. Overall, the present study shows that in addition to the widely recognized astrocytic EAAT2, neuronal EAAT2 plays a role in hippocampus-dependent memory. Furthermore, the gene expression profiles associated with astrocytic and neuronal EAAT2 deletion are substantially different, with the former associated with inflammation and synaptic function similar to changes observed in human AD and gene expression changes associated with inflammation similar to the aging human brain.


Subject(s)
Alzheimer Disease/metabolism , Astrocytes/metabolism , Cognitive Dysfunction/pathology , Excitatory Amino Acid Transporter 2/deficiency , Memory Disorders/pathology , Neurons/metabolism , Adult , Aged, 80 and over , Aging/physiology , Animals , Cognition/physiology , Cognitive Dysfunction/genetics , Excitatory Amino Acid Transporter 2/genetics , Hippocampus/physiology , Humans , Kynurenine/metabolism , Male , Memory Disorders/genetics , Memory, Long-Term/physiology , Memory, Short-Term/physiology , Mice , Mice, Knockout , Middle Aged , Young Adult
2.
Synapse ; 73(5): e22088, 2019 05.
Article in English | MEDLINE | ID: mdl-30632204

ABSTRACT

In adult female, but not male, Sprague Dawley rats, chronic immobilization stress (CIS) increases mossy fiber (MF) Leu-Enkephalin levels and redistributes delta- and mu-opioid receptors (DORs and MORs) in hippocampal CA3 pyramidal cells and GABAergic interneurons to promote excitation and learning processes following subsequent opioid exposure. Here, we demonstrate that CIS females, but not males, acquire conditioned place preference (CPP) to oxycodone and that CIS "primes" the hippocampal opioid system in females for oxycodone-associated learning. In CA3b, oxycodone-injected (Oxy) CIS females relative to saline-injected (Sal) CIS females exhibited an increase in the cytoplasmic and total densities of DORs in pyramidal cell dendrites so that they were similar to Sal- and Oxy-CIS males. Consistent with our earlier studies, Sal- and Oxy-CIS females but not CIS males had elevated DOR densities in MF-CA3 dendritic spines, which we have previously shown are important for opioid-mediated long-term potentiation. In the dentate gyrus, Oxy-CIS females had more DOR-labeled interneurons than Sal-CIS females. Moreover, Sal- and Oxy-CIS females compared to both groups of CIS males had elevated levels of DORs and MORs in GABAergic interneuron dendrites, suggesting capacity for greater synthesis or storage of these receptors in circuits important for opioid-mediated disinhibition. However, more plasmalemmal MORs were on large parvalbumin-containing dendrites of Oxy-CIS males compared to Sal-CIS males, suggesting a limited ability for increased granule cell disinhibition. These results suggest that low levels of DORs in MF-CA3 synapses and hilar GABAergic interneurons may contribute to the attenuation of oxycodone CPP in males exposed to CIS.


Subject(s)
Analgesics, Opioid/pharmacology , CA3 Region, Hippocampal/metabolism , Conditioning, Classical , Dentate Gyrus/metabolism , Oxycodone/pharmacology , Repetition Priming , Stress, Psychological/physiopathology , Animals , CA3 Region, Hippocampal/cytology , CA3 Region, Hippocampal/drug effects , Dendrites/metabolism , Dentate Gyrus/cytology , Dentate Gyrus/drug effects , Female , Interneurons/metabolism , Male , Rats , Rats, Sprague-Dawley , Receptors, Opioid, delta/metabolism , Receptors, Opioid, mu/metabolism , Restraint, Physical , Stress, Psychological/metabolism
3.
Proc Natl Acad Sci U S A ; 112(48): E6614-23, 2015 Dec 01.
Article in English | MEDLINE | ID: mdl-26627253

ABSTRACT

The experience of psychological stress triggers neuroendocrine, inflammatory, metabolic, and transcriptional perturbations that ultimately predispose to disease. However, the subcellular determinants of this integrated, multisystemic stress response have not been defined. Central to stress adaptation is cellular energetics, involving mitochondrial energy production and oxidative stress. We therefore hypothesized that abnormal mitochondrial functions would differentially modulate the organism's multisystemic response to psychological stress. By mutating or deleting mitochondrial genes encoded in the mtDNA [NADH dehydrogenase 6 (ND6) and cytochrome c oxidase subunit I (COI)] or nuclear DNA [adenine nucleotide translocator 1 (ANT1) and nicotinamide nucleotide transhydrogenase (NNT)], we selectively impaired mitochondrial respiratory chain function, energy exchange, and mitochondrial redox balance in mice. The resulting impact on physiological reactivity and recovery from restraint stress were then characterized. We show that mitochondrial dysfunctions altered the hypothalamic-pituitary-adrenal axis, sympathetic adrenal-medullary activation and catecholamine levels, the inflammatory cytokine IL-6, circulating metabolites, and hippocampal gene expression responses to stress. Each mitochondrial defect generated a distinct whole-body stress-response signature. These results demonstrate the role of mitochondrial energetics and redox balance as modulators of key pathophysiological perturbations previously linked to disease. This work establishes mitochondria as stress-response modulators, with implications for understanding the mechanisms of stress pathophysiology and mitochondrial diseases.


Subject(s)
Gene Expression Regulation , Inflammation/pathology , Mitochondria/physiology , Stress, Psychological , Adenine Nucleotide Translocator 1/genetics , Adrenocorticotropic Hormone/blood , Allostasis , Animals , Catecholamines/blood , DNA, Mitochondrial/genetics , Electron Transport Complex IV/genetics , Genotype , Hippocampus/metabolism , Hippocampus/pathology , Interleukin-6/blood , Male , Mice , Mice, Inbred C57BL , Mice, Transgenic , Mitochondria/pathology , Mitochondrial Proteins/genetics , Mutation , NADH Dehydrogenase/genetics , NADP Transhydrogenase, AB-Specific/genetics , Oxidative Stress , Signal Transduction , Transcription, Genetic
4.
Proc Natl Acad Sci U S A ; 111(45): 16130-5, 2014 Nov 11.
Article in English | MEDLINE | ID: mdl-25349423

ABSTRACT

Genetic evidence suggests cell-type-specific functions for certain nucleoporins, and gene expression profiling has revealed that nucleoporin p62 (NUP62) transcripts are decreased in the prefrontal cortex of major depressives. Chronic stress, which can precipitate depression, induces changes in the architecture and plasticity of apical dendrites that are particularly evident in the CA3 region of the hippocampus. Genetically targeted translating ribosome affinity purification revealed a selective reduction in translated Nup62 transcripts in CA3 of chronically stressed mice, and the Nup62 protein content of nuclei extracted from whole hippocampus was found to be decreased in chronically stressed rats. In cultured cells, phosphorylation of a FAK/proline-rich tyrosine kinase 2 (PYK2) consensus site in the alpha-helical domain of NUP62 (human Y422) is shown to be associated with shedding of NUP62 from the nuclear pore complex (NPC) and/or retention of NUP62 in the cytoplasm. Increased levels of phospho-Y425 Nup62 were observed in cytoplasmic fractions of hippocampi from chronically stressed rats, and immunofluorescence microscopy revealed redistribution of activated Pyk2 to the perinuclear region of stressed pyramidal neurons. Depletion of Nup62 from cultured embryonic day 18 rat hippocampal and cortical neurons resulted in simplification and retraction of dendritic arbors, without disruption of axon initial segment integrity. Thus, at least two types of mechanisms--one affecting expression and the other association with the NPC--could contribute to loss of NUP62 from CA3 pyramidal neurons during chronic stress. Their combined actions may account for the enhanced responsiveness of CA3 apical dendrites to chronic stress and may either be pathogenic or serve to protect CA3 neurons from permanent damage.


Subject(s)
CA3 Region, Hippocampal/metabolism , Focal Adhesion Kinase 2/metabolism , Membrane Glycoproteins/metabolism , Nuclear Pore Complex Proteins/metabolism , Pyramidal Cells/metabolism , Stress, Psychological/metabolism , Animals , Axons/metabolism , Axons/pathology , CA3 Region, Hippocampal/pathology , Chronic Disease , Dendrites/metabolism , Dendrites/pathology , Focal Adhesion Kinase 2/genetics , Humans , Membrane Glycoproteins/genetics , Mice , Nuclear Pore Complex Proteins/genetics , Pyramidal Cells/pathology , Rats , Rats, Sprague-Dawley , Stress, Psychological/genetics , Stress, Psychological/pathology
5.
Bioessays ; 36(11): 1072-81, 2014 Nov.
Article in English | MEDLINE | ID: mdl-25213333

ABSTRACT

The brain is an ever-changing organ that encodes memories and directs behavior. Neuroanatomical studies have revealed structural plasticity of neural architecture, and advances in gene expression technology and epigenetics have demonstrated new mechanisms underlying the brain's dynamic nature. Stressful experiences challenge the plasticity of the brain, and prolonged exposure to environmental stress redefines the normative transcriptional profile of both neurons and glia, and can lead to the onset of mental illness. A more thorough understanding of normal and abnormal gene expression is needed to define the diseased brain and improve current treatments for psychiatric disorders. The efforts to describe gene expression networks have been bolstered by microarray and RNA-sequencing technologies. The heterogeneity of neural cell populations and their unique microenvironments, coupled with broad ranging interconnectivity, makes resolving this complexity exceedingly challenging and requires the combined efforts of single cell and systems level expression profiling to identify targets for therapeutic intervention.


Subject(s)
Brain/metabolism , Mental Disorders/genetics , Neuronal Plasticity/genetics , Animals , Base Sequence , Epigenesis, Genetic , Gene Expression Profiling , Gene Expression Regulation , Gene Regulatory Networks , Glucocorticoids/metabolism , Humans , Mice , Sequence Analysis, RNA , Transcriptome/genetics
6.
Hum Mol Genet ; 22(21): 4267-81, 2013 Nov 01.
Article in English | MEDLINE | ID: mdl-23773994

ABSTRACT

Low-density lipoprotein receptor related protein 6 (Lrp6) mutational effects on neurulation were examined using gain (Crooked tail, Lrp6(Cd)) and loss (Lrp6(-)) of function mouse lines. Two features often associated with canonical Wnt signaling, dorsal-ventral patterning and proliferation, were no different from wild-type (WT) in the Lrp6(Cd/Cd) neural tube. Lrp6(-/-) embryos showed reduced proliferation and subtle patterning changes in the neural folds. Cell polarity defects in both Lrp6(Cd/Cd) and Lrp6(-/-) cranial folds were indicated by cell shape, centrosome displacement and failure of F-actin and GTP-RhoA accumulation at the apical surface. Mouse embryonic fibroblasts (MEFs) derived from Lrp6(Cd/Cd) or Lrp6(-/-) embryos exhibited elevated and decreased RhoA basal activity levels, respectively. While ligand-independent activation of canonical Wnt signaling, bypassing Lrp-Frizzled receptors, did not activate RhoA, non-canonical Wnt5a stimulation of RhoA activity was impaired in Lrp6(-/-) MEFs. RhoA inhibition exacerbated NTDs in cultured Lrp6 knockout embryos compared with WT littermates. In contrast, a ROCK inhibitor rescued Lrp6(Cd/Cd) embryos from NTDs. Lrp6 co-immunoprecipitated with Disheveled-associated activator of morphogenesis 1 (DAAM1), a formin promoting GEF activity in Wnt signaling. Biochemical and cell biological data revealed intracellular accumulation of Lrp6(Cd) protein where interaction with DAAM1 could account for observed elevated RhoA activity. Conversely, null mutation that eliminates Lrp6 interaction with DAAM1 led to lower basal RhoA activity in Lrp6(-/-) embryos. These results indicate that Lrp6 mediates not only canonical Wnt signaling, but can also modulate non-canonical pathways involving RhoA-dependent mechanisms to impact neurulation, possibly through intracellular complexes with DAAM1.


Subject(s)
Low Density Lipoprotein Receptor-Related Protein-6/metabolism , Low Density Lipoprotein Receptor-Related Protein-6/physiology , Neural Tube/embryology , Wnt Proteins/metabolism , Wnt Signaling Pathway , Adaptor Proteins, Signal Transducing/genetics , Adaptor Proteins, Signal Transducing/metabolism , Alleles , Animals , Cell Polarity , Embryo, Mammalian , Female , Gene Expression Regulation, Developmental , HEK293 Cells , Humans , Low Density Lipoprotein Receptor-Related Protein-6/genetics , Mice , Mice, Transgenic , Microfilament Proteins/genetics , Microfilament Proteins/metabolism , NIH 3T3 Cells , Neural Crest/metabolism , Neural Tube/physiology , Neurulation/genetics , Pregnancy , Wnt Proteins/genetics , rho GTP-Binding Proteins/genetics , rho GTP-Binding Proteins/metabolism , rhoA GTP-Binding Protein/genetics , rhoA GTP-Binding Protein/metabolism
7.
Birth Defects Res A Clin Mol Teratol ; 100(8): 623-32, 2014 Aug.
Article in English | MEDLINE | ID: mdl-25115437

ABSTRACT

BACKGROUND: Neural tube closure defects (NTDs) are among the most common congenital malformation in human, typically presenting in liveborns as spina bifida. At least 240 gene mutations in mouse are known to increase the risk of NTD. There is a growing appreciation that environmental factors significantly contribute to NTD expression, and that NTDs likely arise from complex gene-environment interactions. Because maternal folic acid supplementation reduces human NTD risk in some populations by 60 to 70%, it is likely that NTD predisposition is often associated with a defect in folate-dependent one-carbon metabolism. A comprehensive, untargeted metabolic survey of NTD-associated changes in embryo metabolism would provide a valuable test of this assumption. We sought to establish a metabolic profiling platform that is capable of broadly assessing metabolic aberrations associated with NTD-promoting gene mutations in early-stage mouse embryos. METHODS: A liquid chromatography/mass spectrometry-based untargeted metabolite profiling platform was used to broadly identify significant differences in small molecule levels (50-1000 Da) in NTD-affected embryonic day (E) 9.5 mouse embryos (Lrp6(-) (/) (-) ) versus unaffected (Lrp6(+/+) ) control embryos. RESULTS: Results provide proof-of-principal feasibility for the broad survey of the metabolome of individual E9.5 mouse embryos and identification of metabolic changes associated with NTDs and gene mutations. Levels of 30 different metabolites were altered in association with Lrp6 gene deletion. Some metabolites link to folate-dependent one-carbon transfer reactions, as anticipated, while others await structure elucidation and pathway integration. CONCLUSION: Whole-embryo metabolomics offers the potential to identify metabolic changes in genetically determined NTD-prone embryos.


Subject(s)
Folic Acid/metabolism , Low Density Lipoprotein Receptor-Related Protein-6/genetics , Neural Tube Defects/embryology , Neural Tube/embryology , Spinal Dysraphism/embryology , Animals , Disease Models, Animal , Glutathione/metabolism , Metabolome/genetics , Mice , Mice, Knockout , Neural Tube/metabolism , Neural Tube Defects/genetics , Neural Tube Defects/metabolism , Oxidation-Reduction , Oxidative Stress/genetics , Spinal Dysraphism/genetics
8.
Hum Mol Genet ; 19(23): 4560-72, 2010 Dec 01.
Article in English | MEDLINE | ID: mdl-20843827

ABSTRACT

Crooked tail (Cd) mice bear a gain-of-function mutation in Lrp6, a co-receptor for canonical WNT signaling, and are a model of neural tube defects (NTDs), preventable with dietary folic acid (FA) supplementation. Whether the FA response reflects a direct influence of FA on LRP6 function was tested with prenatal supplementation in LRP6-deficient embryos. The enriched FA (10 ppm) diet reduced the occurrence of birth defects among all litters compared with the control (2 ppm FA) diet, but did so by increasing early lethality of Lrp6(-/-) embryos while actually increasing NTDs among nulls alive at embryonic days 10-13 (E10-13). Proliferation in cranial neural folds was reduced in homozygous Lrp6(-/-) mutants versus wild-type embryos at E10, and FA supplementation increased proliferation in wild-type but not mutant neuroepithelia. Canonical WNT activity was reduced in LRP6-deficient midbrain-hindbrain at E9.5, demonstrated in vivo by a TCF/LEF-reporter transgene. FA levels in media modulated the canonical WNT response in NIH3T3 cells, suggesting that although FA was required for optimal WNT signaling, even modest FA elevations attenuated LRP5/6-dependent canonical WNT responses. Gene expression analysis in embryos and adults showed striking interactions between targeted Lrp6 deficiency and FA supplementation, especially for mitochondrial function, folate and methionine metabolism, WNT signaling and cytoskeletal regulation that together implicate relevant signaling and metabolic pathways supporting cell proliferation, morphology and differentiation. We propose that FA supplementation rescues Lrp6(Cd/Cd) fetuses by normalizing hyperactive WNT activity, whereas in LRP6-deficient embryos, added FA further attenuates reduced WNT activity, thereby compromising development.


Subject(s)
Folic Acid/administration & dosage , LDL-Receptor Related Proteins/metabolism , Neural Crest , Neural Tube Defects , Wnt Proteins/metabolism , Animals , Dietary Supplements , Disease Models, Animal , Folic Acid/metabolism , Folic Acid/pharmacology , Gene Expression , Gene Expression Regulation, Developmental , Immunohistochemistry , LDL-Receptor Related Proteins/deficiency , LDL-Receptor Related Proteins/genetics , Low Density Lipoprotein Receptor-Related Protein-6 , Methionine/metabolism , Mice , Mice, Inbred C3H , Mitochondria/metabolism , Mutation , NIH 3T3 Cells , Neural Crest/abnormalities , Neural Crest/drug effects , Neural Crest/growth & development , Neural Tube Defects/embryology , Neural Tube Defects/genetics , Neural Tube Defects/metabolism , Neural Tube Defects/prevention & control , Polymerase Chain Reaction , RNA, Messenger/genetics , Sequence Analysis, DNA , Signal Transduction/drug effects , Wnt Proteins/genetics
9.
J Comp Neurol ; 529(10): 2636-2657, 2021 07 01.
Article in English | MEDLINE | ID: mdl-33483980

ABSTRACT

Chronic immobilization stress (CIS) results in sex-dependent changes in opioid peptide levels and receptor subcellular distributions within the rat dorsal hippocampus, which are paralleled with an inability for males to acquire conditioned place preference (CPP) to oxycodone. Here, RNAScope in situ hybridization was used to determine the expression of hippocampal opioid peptides and receptors in unstressed (US) and CIS estrus female and male adult (∼2.5 months old ) Sprague Dawley rats. In all groups, dentate granule cells expressed PENK and PDYN; additionally, numerous interneurons expressed PENK. OPRD1 and OPRM1 were primarily expressed in interneurons, and to a lesser extent, in pyramidal and granule cells. OPRK1-was expressed in sparsely distributed interneurons. There were few baseline sex differences: US females compared to US males had more PENK-expressing and fewer OPRD1-expressing granule cells and more OPRM1-expressing CA3b interneurons. Several expression differences emerged after CIS. Both CIS females and males compared to their US counterparts had elevated: (1) PENK-expressing dentate granule cells and interneurons in CA1 and CA2/3a; (2) OPRD1 probe number and cell expression in CA1, CA2/3a and CA3b and the dentate gyrus; and (3) OPRK1-expressing interneurons in the dentate hilus. Also, CIS males compared to US males had elevated: (1) PDYN expression in granule cells; (2) OPRD1 probe and interneuron expression in CA2/3a; (3) OPRM1 in granule cells; and (4) OPRK1 interneuron expression in CA2/3a. The sex-specific changes in hippocampal opioid gene expression may impact network properties and synaptic plasticity processes that may contribute to the attenuation of oxycodone CPP in CIS males.


Subject(s)
Hippocampus/metabolism , Opioid Peptides/metabolism , Receptors, Opioid/metabolism , Stress, Psychological/metabolism , Animals , Female , Male , RNA, Messenger , Rats , Rats, Sprague-Dawley , Restraint, Physical , Sex Characteristics
10.
Exp Neurol ; 325: 113075, 2020 03.
Article in English | MEDLINE | ID: mdl-31837319

ABSTRACT

Obstructive sleep apnea (OSA), a chronic sleep disorder characterized by repetitive reduction or cessation of airflow during sleep, is widely prevalent and is associated with adverse neurocognitive sequelae including increased risk of Alzheimer's disease (AD). In humans, OSA is more common in elderly males. OSA is characterized by sleep fragmentation and chronic intermittent hypoxia (CIH), and recent epidemiological studies point to CIH as the best predictor of neurocognitive sequelae associated with OSA. The sex- and age- specific effects of OSA-associated CIH on specific cell populations such as γ-aminobutyric acid (GABA)-ergic neurons in the hippocampus and the medial prefrontal cortex (mPFC), regions important for cognitive function, remain largely unknown. The present study examined the effect of 35 days of either moderate (10% oxygen) or severe (5% oxygen) CIH on GABAergic neurons in the mPFC and hippocampus of young and aged male and female mice as well as post-accelerated ovarian failure (AOF) female mice. In the mPFC and hippocampus, the number of GABA-labeled neurons increased in aged and young severe CIH males compared to controls but not in young moderate CIH males. This change was not representative of the individual GABAergic cell subpopulations, as the number of parvalbumin-labeled neurons decreased while the number of somatostatin-labeled neurons increased in the hippocampus of severe CIH young males only. In all female groups, the number of GABA-labeled cells was not different between CIH and controls. However, in the mPFC, CIH increased the number of parvalbumin-labeled neurons in young females and the number of somatostatin-labeled cells in AOF females but decreased the number of somatostatin-labeled cells in aged females. In the hippocampus, CIH decreased the number of somatostatin-labeled neurons in young females. CIH decreased the density of vesicular GABA transporter in the mPFC of AOF females only. These findings suggest sex-specific changes in GABAergic neurons in the hippocampus and mPFC with males showing an increase of this cell population as compared to their female counterparts following CIH. Age at exposure and severity of CIH also differentially affect the GABAergic cell population in mice.


Subject(s)
GABAergic Neurons/pathology , Hippocampus/pathology , Hypoxia, Brain/pathology , Prefrontal Cortex/pathology , Age Factors , Animals , Cell Count , Female , Hippocampus/metabolism , Hypoxia, Brain/metabolism , Male , Mice , Mice, Inbred C57BL , Prefrontal Cortex/metabolism , Sex Characteristics
11.
Neurobiol Stress ; 13: 100236, 2020 Nov.
Article in English | MEDLINE | ID: mdl-33344692

ABSTRACT

Following oxycodone (Oxy) conditioned place preference (CPP), delta opioid receptors (DORs) differentially redistribute in hippocampal CA3 pyramidal cells in female and male rats in a manner that would promote plasticity and opioid-associative learning processes. However, following chronic immobilization stress (CIS), males do not acquire Oxy-CPP and the trafficking of DORs in CA3 pyramidal neurons is attenuated. Here, we examined the subcellular distribution of DORs in CA1 pyramidal cells using electron microscopy in these same cohorts. CPP: Saline (Sal)-females compared to Sal-males have more cytoplasmic and total DORs in dendrites and more DOR-labeled spines. Following Oxy-CPP, DORs redistribute from near-plasmalemma pools in dendrites to spines in males. CIS: Control females compared to control males have more near-plasmalemmal dendritic DORs. Following CIS, dendritic DORs are elevated in the cytoplasm in females and near-plasmalemma in males. CIS PLUS CPP: CIS Sal-females compared to CIS Sal-males have more DORs on the plasmalemma of dendrites and in spines. After Oxy, the distribution of DORs does not change in either females or males. CONCLUSION: Following Oxy-CPP, DORs within CA1 pyramidal cells remain positioned in naïve female rats to enhance sensitivity to DOR agonists and traffic to dendritic spines in naïve males where they can promote plasticity processes. Following CIS plus behavioral enrichment, DORs are redistributed within CA1 pyramidal cells in females in a manner that could enhance sensitivity to DOR agonists. Conversely, CIS plus behavioral enrichment does not alter DORs in CA1 pyramidal cells in males, which may contribute to their diminished capacity to acquire Oxy-CPP.

12.
Birth Defects Res A Clin Mol Teratol ; 85(4): 314-21, 2009 Apr.
Article in English | MEDLINE | ID: mdl-19067399

ABSTRACT

Despite two decades of research since Smithells and colleagues began exploring its benefits, the mechanisms through which folic acid supplementation supports neural tube closure and early embryonic development are still unclear. The greatest progress toward a molecular-genetic understanding of folate effects on neural tube defect (NTD) pathogenesis has come from animal models. The number of NTD-associated mouse mutants accumulated and studied over the past decade has illuminated the complexity of both genetic factors contributing to NTDs and also NTD-gene interactions with folate metabolism. This article discusses insights gained from mouse models into how folate supplementation impacts neurulation. A case is made for renewed efforts to systematically screen the folate responsiveness of the scores of NTD-associated mouse mutations now identified. Designed after Crooked tail, supplementation studies of additional mouse mutants could build the molecular network maps that will ultimately enable tailoring of therapeutic regimens to individual families.


Subject(s)
Dietary Supplements , Folic Acid/pharmacology , Metabolic Networks and Pathways/drug effects , Neural Tube Defects/metabolism , Tail/abnormalities , Animals , Body Patterning/drug effects , Body Patterning/genetics , Female , Folic Acid/administration & dosage , Genetic Predisposition to Disease , Metabolic Networks and Pathways/genetics , Mice , Mice, Mutant Strains , Models, Biological , Neural Tube Defects/genetics , Neural Tube Defects/pathology , Neural Tube Defects/prevention & control , Pregnancy , Tail/metabolism
13.
Transl Psychiatry ; 9(1): 61, 2019 02 04.
Article in English | MEDLINE | ID: mdl-30718469

ABSTRACT

The author's name was spelled incorrectly as "Masahir Okamoto". This has been updated to "Masahiro Okamoto" in the HTML and PDF of the article.

14.
Neurosci Lett ; 713: 134514, 2019 11 20.
Article in English | MEDLINE | ID: mdl-31560995

ABSTRACT

Following oxycodone conditioned place preference (CPP) in naïve female and male Sprague Dawley rats, delta- and mu-opioid receptors (DORs and MORs) redistribute in hippocampal CA3 pyramidal cells and GABAergic interneurons in a manner that would promote opioid-associative learning processes, particularly in females. MORs and DORs similarly redistribute in CA3 and hilar neurons following chronic immobilization stress (CIS) in females, but not males, essentially "priming" the opioid system for oxycodone-associative learning. Following CIS, only females acquire oxycodone CPP. The present study determined whether sex and CIS differentially affect the levels of phosphorylated MORs and DORs (pMORs and pDORs) in the hippocampus following oxycodone CPP as phosphorylation is important for opioid receptor internationalization and trafficking. In naïve oxycodone-injected (Oxy) female rats, the density of pMOR-immunoreactivity (ir) was increased in CA1 stratum oriens and CA3a,b strata lucidum and radiatum compared to saline-injected (Sal)-females. Additionally, the density of pDOR-ir increased in the pyramidal cell layer and stratum radiatum of CA2/3a in Oxy-males compared to Sal-males. In CIS females that acquire CPP, pDOR-ir levels were increased in the CA2/3a. These findings indicate only rats that acquire oxycodone CPP have activated MORs and DORs in the hippocampus but that the subregion containing activated opioid receptors differs in females and males. These results are consistent with previously observed sex differences in the hippocampal opioid system following Oxy-CPP.


Subject(s)
Conditioning, Classical/physiology , Hippocampus/metabolism , Oxycodone/pharmacology , Receptors, Opioid, delta/metabolism , Receptors, Opioid, mu/metabolism , Sex Characteristics , Stress, Psychological/metabolism , Animals , Female , Immobilization , Male , Phosphorylation/physiology , Pyramidal Cells/metabolism , Rats
15.
Front Behav Neurosci ; 13: 157, 2019.
Article in English | MEDLINE | ID: mdl-31354448

ABSTRACT

Early life experiences program brain structure and function and contribute to behavioral endophenotypes in adulthood. Epigenetic control of gene expression by those experiences affect discrete brain regions involved in mood, cognitive function and regulation of hypothalamic-pituitary-adrenal (HPA) axis. In rodents, acute restraint stress increases the expression of the repressive histone H3 lysine 9 tri-methylation (H3K9me3) in hippocampal fields, including the CA3 pyramidal neurons. These CA3 neurons are crucially involved in cognitive function and mood regulation as well as activation of glucocorticoid (CORT) secretion. CA3 neurons also exhibit structural and functional changes after early-life stress (ELS) as well as after chronic stress in adulthood. Using a protocol of chronic ELS induced by limited bedding and nesting material followed by acute-swim stress (AS) in adulthood, we show that mice with a history of ELS display a blunted CORT response to AS, despite exhibiting activation of immediate early genes after stress similar to that found in control mice. We find that ELS induced persistently increased expression of the repressive H3K9me3 histone mark in the CA3 subfield at baseline that was subsequently decreased following AS. In contrast, AS induced a transient increase of this mark in control mice. Using translating ribosome affinity purification (TRAP) method to isolate CA3 translating mRNAs, we found that expression of genes of the epigenetic gene family, GABA/glutamate family, and glucocorticoid receptors binding genes were decreased transiently in control mice by AS and showed a persistent reduction in ELS mice. In most cases, AS in ELS mice did not induce gene expression changes. A stringent filtering of genes affected by AS in control and ELS mice revealed a noteworthy decrease in gene expression change in ELS mice compared to control. Only 18 genes were selectively regulated by AS in ELS mice and encompassed pathways such as circadian rhythm, inflammatory response, opioid receptors, and more genes included in the glucocorticoid receptor binding family. Thus, ELS programs a restricted translational response to stress in stress-sensitive CA3 neurons leading to persistent changes in gene expression, some of which mimic the transient effects of AS in control mice, while leaving in operation the immediate early gene response to AS.

16.
Neuroscience ; 410: 274-292, 2019 07 01.
Article in English | MEDLINE | ID: mdl-31071414

ABSTRACT

Prescription opioid abuse is a serious public health issue. Recently, we showed that female and male Sprague-Dawley rats acquire conditioned place preference (CPP) to the mu opioid receptor agonist oxycodone. Anatomical analysis of the hippocampus from these rats unveiled sex differences in the opioid system in a way that would support excitation and opiate associative learning processes especially in females. In this study, we examined the expression and protein densities of opioid, plasticity, stress and related kinase and signaling molecules in the hippocampus of female and male rats following oxycodone CPP. Oxycodone CPP females have: a) increases in ARC (activity regulated cytoskeletal-associated protein)-immunoreactivity (ir) in CA3 pyramidal cells; b) decreases in Npy (neuropeptide Y) gene expression in the medial hippocampus but higher numbers of NPY-containing hilar interneurons compared to males; c) increases in Crhr2 (corticotropin releasing factor receptor 2) expression in CA2/3; d) increases in Akt1 (AKT serine/threonine kinase 1) expression in medial hippocampus; and e) decreases in phosphorylated MAPK (mitogen activated protein kinase)-ir in CA1 and dentate gyrus. Oxycodone CPP males have: a) increases in Bdnf (brain derived-neurotrophic factor) expression, which is known to be produced in granule cells, relative to females; b) elevated Mapk1 expression and pMAPK-ir in the dentate hilus which harbors newly generated granule cells; and c) increases in CRHR1-ir in CA3 pyramidal cell soma. These sex-specific changes in plasticity, stress and kinase markers in hippocampal circuitry parallel previously observed sex differences in the opioid system after oxycodone CPP.


Subject(s)
Analgesics, Opioid/pharmacology , Conditioning, Psychological/physiology , Neuronal Plasticity/physiology , Oxycodone/pharmacology , Sex Characteristics , Stress, Psychological/metabolism , Animals , Brain-Derived Neurotrophic Factor/metabolism , Conditioning, Psychological/drug effects , Female , Gene Expression , Hippocampus/drug effects , Hippocampus/metabolism , Male , Mitogen-Activated Protein Kinase Kinases/metabolism , Neuronal Plasticity/drug effects , Rats , Rats, Sprague-Dawley , Stress, Psychological/genetics
17.
J Neurosci ; 27(27): 7196-207, 2007 Jul 04.
Article in English | MEDLINE | ID: mdl-17611273

ABSTRACT

Thousands of children receive methylphenidate (MPH; Ritalin) for attention deficit/hyperactivity disorder (ADHD), yet the long-term neurochemical consequences of MPH treatment are unknown. To mimic clinical Ritalin treatment in children, male rats were injected with MPH (5 mg/kg) or vehicle twice daily from postnatal day 7 (PND7)-PND35. At the end of administration (PND35) or in adulthood (PND135), brain sections from littermate pairs were immunocytochemically labeled for neurotransmitters and cytological markers in 16 regions implicated in MPH effects and/or ADHD etiology. At PND35, the medial prefrontal cortex (mPFC) of rats given MPH showed 55% greater immunoreactivity (-ir) for the catecholamine marker tyrosine hydroxylase (TH), 60% more Nissl-stained cells, and 40% less norepinephrine transporter (NET)-ir density. In hippocampal dentate gyrus, MPH-receiving rats showed a 51% decrease in NET-ir density and a 61% expanded distribution of the new-cell marker PSA-NCAM (polysialylated form of neural cell adhesion molecule). In medial striatum, TH-ir decreased by 21%, and in hypothalamus neuropeptide Y-ir increased by 10% in MPH-exposed rats. At PND135, MPH-exposed rats exhibited decreased anxiety in the elevated plus-maze and a trend for decreased TH-ir in the mPFC. Neither PND35 nor PND135 rats showed major structural differences with MPH exposure. These findings suggest that developmental exposure to high therapeutic doses of MPH has short-term effects on select neurotransmitters in brain regions involved in motivated behaviors, cognition, appetite, and stress. Although the observed neuroanatomical changes largely resolve with time, chronic modulation of young brains with MPH may exert effects on brain neurochemistry that modify some behaviors even in adulthood.


Subject(s)
Appetite/drug effects , Brain/drug effects , Cognition/drug effects , Methylphenidate/administration & dosage , Motivation , Stress, Physiological/prevention & control , Age Factors , Animals , Appetite/physiology , Behavior, Animal/drug effects , Behavior, Animal/physiology , Brain/metabolism , Cognition/physiology , Female , Male , Pregnancy , Rats , Rats, Sprague-Dawley , Stress, Physiological/metabolism
18.
Transl Psychiatry ; 8(1): 153, 2018 08 14.
Article in English | MEDLINE | ID: mdl-30108205

ABSTRACT

Alzheimer's disease (AD) represents a major healthcare burden with no effective treatment. The glutamate modulator, riluzole, was shown to reverse many AD-related gene expression changes and improve cognition in aged rats. However, riluzole's effect on amyloid beta (Aß) pathology, a major histopathological hallmark of AD, remains unclear. 5XFAD transgenic mice, which harbor amyloid ß precursor protein (APP) and presenilin mutations and exhibit early Aß accumulation, were treated with riluzole from 1 to 6 months of age. Riluzole significantly enhanced cognition and reduced Aß42, Aß40, Aß oligomers levels, and Aß plaque load in 5XFAD mice. RNA-Sequencing showed that riluzole reversed many gene expression changes observed in the hippocampus of 5XFAD mice, predominantly in expression of canonical gene markers for microglia, specifically disease-associated microglia (DAM), as well as neurons and astrocytes. Central to the cognitive improvements observed, riluzole reversed alterations in NMDA receptor subunits gene expression, which are essential for learning and memory. These data demonstrate that riluzole exerts a disease modifying effect in an Aß mouse model of early-onset familial AD.


Subject(s)
Alzheimer Disease/drug therapy , Memory/drug effects , Plaque, Amyloid/drug therapy , Receptors, N-Methyl-D-Aspartate/drug effects , Riluzole/pharmacology , Animals , Astrocytes/drug effects , Cognition/drug effects , Disease Models, Animal , Gene Expression/drug effects , Hippocampus/drug effects , Male , Mice , Mice, Inbred C57BL , Mice, Transgenic , Microglia/drug effects , Sequence Analysis, RNA
19.
Neuroscience ; 393: 236-257, 2018 11 21.
Article in English | MEDLINE | ID: mdl-30316908

ABSTRACT

Although opioid addiction has risen dramatically, the role of gender in addiction has been difficult to elucidate. We previously found sex-dependent differences in the hippocampal opioid system of Sprague-Dawley rats that may promote associative learning relevant to drug abuse. The present studies show that although female and male rats acquired conditioned place preference (CPP) to the mu-opioid receptor (MOR) agonist oxycodone (3 mg/kg, I.P.), hippocampal opioid circuits were differentially altered. In CA3, Leu-Enkephalin-containing mossy fibers had elevated levels in oxycodone CPP (Oxy) males comparable to those in females and sprouted in Oxy-females, suggesting different mechanisms for enhancing opioid sensitivity. Electron microscopy revealed that in Oxy-males delta opioid receptors (DORs) redistributed to mossy fiber-CA3 synapses in a manner resembling females that we previously showed is important for opioid-mediated long-term potentiation. Moreover, in Oxy-females DORs redistributed to CA3 pyramidal cell spines, suggesting the potential for enhanced plasticity processes. In Saline-injected (Sal) females, dentate hilar parvalbumin-containing basket interneuron dendrites had fewer MORs, however plasmalemmal and total MORs increased in Oxy-females. In dentate hilar GABAergic dendrites that contain neuropeptide Y, Sal-females compared to Sal-males had higher plasmalemmal DORs, and near-plasmalemmal DORs increased in Oxy-females. This redistribution of MORs and DORs within hilar interneurons in Oxy-females would potentially enhance disinhibition of granule cells via two different circuits. Together, these results indicate that oxycodone CPP induces sex-dependent redistributions of opioid receptors in hippocampal circuits in a manner facilitating opioid-associative learning processes and may help explain the increased susceptibility of females to opioid addiction acquisition and relapse.


Subject(s)
Hippocampus/drug effects , Oxycodone/pharmacology , Sex Characteristics , Animals , Hippocampus/metabolism , Interneurons/drug effects , Interneurons/metabolism , Long-Term Potentiation/drug effects , Male , Neurons/drug effects , Neurons/metabolism , Pyramidal Cells/drug effects , Pyramidal Cells/metabolism , Rats , Rats, Sprague-Dawley , Receptors, Opioid, delta/drug effects , Receptors, Opioid, delta/metabolism , Receptors, Opioid, mu/drug effects , Receptors, Opioid, mu/metabolism
20.
Neurobiol Stress ; 8: 33-41, 2018 Feb.
Article in English | MEDLINE | ID: mdl-29888302

ABSTRACT

Opioid peptides and their receptors re-organize within hippocampal neurons of female, but not male, rats following chronic immobilization stress (CIS) in a manner that promotes drug-related learning. This study was conducted to determine if there are also sex differences in gene expression in the hippocampus following CIS. Adult female and male rats were subjected to CIS (30 min/day) for 10 days. Twenty-four hours after the last stressor, the rats were euthanized, the brains were harvested and the medial (dentate gyrus/CA1) and lateral (CA2/CA3) dorsal hippocampus were isolated. Following total RNA isolation, cDNA was prepared for gene expression analysis using a RT2 Profiler PCR expression array. This custom designed qPCR expression array contained genes for opioid peptides and receptors, as well as genes involved in stress-responses and candidate genes involved in synaptic plasticity, including those upregulated following oxycodone self-administration in mice. Few sex differences are seen in hippocampal gene expression in control (unstressed) rats. In response to CIS, gene expression in the hippocampus was altered in males but not females. In males, opioid, stress, plasticity and kinase/signaling genes were all down-regulated following CIS, except for the gene that codes for corticotropin releasing hormone, which was upregulated. Changes in opioid gene expression following chronic stress were limited to the CA2 and CA3 regions (lateral sample). In conclusion, modest sex- and regional-differences are seen in expression of the opioid receptor genes, as well as genes involved in stress and plasticity responses in the hippocampus following CIS.

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