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1.
J Microbiol Biol Educ ; 25(1): e0007423, 2024 Apr 25.
Artigo em Inglês | MEDLINE | ID: mdl-38661414

RESUMO

Case studies present students with an opportunity to learn and apply course content through problem solving and critical thinking. Supported by the High-throughput Discovery Science & Inquiry-based Case Studies for Today's Students (HITS) Research Coordination Network, our interdisciplinary team designed, implemented, and assessed two case study modules entitled "You Are What You Eat." Collectively, the case study modules present students with an opportunity to engage in experimental research design and the ethical considerations regarding microbiome research and society. In this manuscript, we provide instructors with tools for adopting or adapting the research design and/or the ethics modules. To date, the case has been implemented using two modalities (remote and in-person) in three courses (Microbiology, Physiology, and Neuroscience), engaging over 200 undergraduate students. Our assessment data demonstrate gains in content knowledge and students' perception of learning following case study implementation. Furthermore, when reflecting on our experiences and student feedback, we identified ways in which the case study could be modified for different settings. In this way, we hope that the "You Are What You Eat" case study modules can be implemented widely by instructors to promote problem solving and critical thinking in the traditional classroom or laboratory setting when discussing next-generation sequencing and/or metagenomics research.

2.
J Undergrad Neurosci Educ ; 21(2): A108-A116, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37588653

RESUMO

Case studies are a valuable teaching tool to engage students in course content using real-world scenarios. As part of the High-throughput Discovery Science & Inquiry-based Case Studies for Today's Students (HITS) Research Coordination Network (RCN), our team has created the Sleepy Mice Case Study for students to engage with RStudio and the Allen Institute for Brain Science's open access high-throughput sleep dataset on mice. Sleep is important for health, a familiar concern to college students, and was a basis for this case study. In this case, students completed an initial homework assignment, in-class work, and a final take-home application assignment. The case study was implemented in synchronous and asynchronous Introductory Neuroscience courses, a Biopsychology course, and a Human Anatomy and Physiology course, reflecting its versatility. The case can be used to teach course-specific learning objectives such as sleep-related content and/or science data processing skills. The case study was successful as shown by gains in student scores and confidence in achieving learning objectives. Most students reported enjoying learning about sleep deprivation course content using the case study. Best practices based on instructor experiences in implementation are also included to facilitate future use so that the Sleepy Mice Case Study can be used to teach content and/or research-related skills in various courses and modalities.

3.
J Undergrad Neurosci Educ ; 22(1): A66-A73, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-38322396

RESUMO

Case studies are a high impact educational practice that engage students in collaborative problem solving through storytelling. HITS, an NSF funded research coordination network dedicated to exposing students to high-throughput discovery science, drove creation of this case. In this case, students imagine themselves as researchers developing new therapeutic drugs for epilepsy. Specifically, students work with the Allen Cell Types Database, which is the result of collaborative, interdisciplinary open science. Neurosurgeons partnered with the Allen institute to provide living human brain tissue for electrophysiological, morphological, and transcriptomic study. Students collaborate to collect and organize data, investigate a research question they identified, and perform fundamental statistical analyses to address their question. By leveraging the unique Cell Types dataset the case enhances student knowledge of epilepsy, illuminates high-throughput scientific approaches, and builds quantitative and research related skills. The case is also versatile and was implemented in two distinct courses. The case can also be taught in different modalities, in person or remote, with a combination of synchronous and asynchronous work. Indirect and direct measures along with quantitative and qualitative approaches were used for case assessment and improvement. Students performed well on case related exam questions, reported high confidence in their achievement of the learning outcomes, and enjoyed the case's link to neurological disease, real research data and advanced technological approaches. Our assessment findings and instructor implementation experiences are also included to facilitate the adoption or adaptation of the case for a variety of courses and/or modalities in neuroscience and STEM related curricula.

4.
J Undergrad Neurosci Educ ; 19(2): A226-A259, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34552440

RESUMO

Neuroscience research is changing at an incredible pace due to technological innovation and recent national and global initiatives such as the BRAIN initiative. Given the wealth of data supporting the value of course-based undergraduate research experiences (CUREs) for students, we developed and assessed a neurotechnology CURE, Mapping the Brain. The goal of the course is to immerse undergraduate and graduate students in research and to explore technological advances in neuroscience. In the laboratory portion of the course, students pursued a hypothesis-driven, collaborative National Institutes of Health (NIH) research project. Using chemogenetic technology (Designer Receptors Exclusively Activated by Designer Drugs-DREADDs) and a recombinase-based intersectional genetic strategy, students mapped norepinephrine neurons, and their projections and explored the effects of activating these neurons in vivo. In lecture, students compared traditional and cutting-edge neuroscience methodologies, analyzed primary literature, designed hypothesis-based experiments, and discussed technological limitations of studying the brain. Over two consecutive years in the Program at North Carolina State University, we assessed student learning and perceptions of learning based on Society for Neuroscience's (SfN) core concepts and essential principles of neuroscience. Using analysis of student assignments and pre/post content and perception-based course surveys, we also assessed whether the course improved student research article analysis and neurotechnology assessment. Our analyses reveal new insights and pedagogical approaches for engaging students in research and improving their critical analysis of research articles and neurotechnologies. Our data also show that our multifaceted approach increased student confidence and promoted a data focused mentality when tackling research literature. Through the integration of authentic research and a neurotechnology focus, Mapping the Brain provides a unique model as a modern neuroscience laboratory course.

5.
Artigo em Inglês | MEDLINE | ID: mdl-33884065

RESUMO

Pandemic SARS-CoV-2 has ushered in a renewed interest in science along with rapid changes to educational modalities. While technology provides a variety of ways to convey learning resources, the incorporation of alternate modalities can be intimidating for those designing curricula. We propose strategies to permit rapid adaptation of curricula to achieve learning in synchronous, asynchronous, or hybrid learning environments. Case studies are a way to engage students in realistic scenarios that contextualize concepts and highlight applications in the life sciences. While case studies are commonly available and adaptable to course goals, the practical considerations of how to deliver and assess cases in online and blended environments can instill panic. Here we review existing resources and our collective experiences creating, adapting, and assessing case materials across different modalities. We discuss the benefits of using case studies and provide tips for implementation. Further, we describe functional examples of a three-step process to prepare cases with defined outcomes for individual student preparation, collaborative learning, and individual student synthesis to create an inclusive learning experience, whether in a traditional or remote learning environment.

6.
Biochem Mol Biol Educ ; 49(1): 115-128, 2021 01.
Artigo em Inglês | MEDLINE | ID: mdl-33176069

RESUMO

The rapid development of molecular biotechnology presents a curricular challenge for educators trying to provide students with relevant coursework. A comprehensive biology education should also include opportunities for students to develop intellectual and technical skills through authentic research experiences. Integrating relevant and interesting research projects into their classes, however, can be a challenging task for instructors. To address these varied demands, we redesigned our existing molecular cloning course to incorporate an independent research project assessing calcium signaling. In the revised course, students use traditional and recombination-based cloning strategies to generate bacterial and mammalian expression vectors encoding CaMPARI, a novel fluorescent calcium indicator. Bacterially-expressed CaMPARI is used in protein quantification and purification assays. Students must also design their own research project evaluating the effect of chemotherapeutic agents on calcium signaling in a mammalian system. Revised and novel labs were designed to be modular, facilitating their integration into the course over 2 years. End-of-semester student evaluations were compared between years revealing a significant difference in students' perception of the course's difficulty between years. This change in attitude highlights potential pedagogical considerations that must be examined when introducing new material and activities into existing courses. Since calcium signaling is important for cellular process across diverse species, instructors may be able to develop research projects within their respective areas of interest. Integration of authentic research experiences into the curriculum is challenging; however, the framework described here provides a versatile structure that can be adapted to merge diverse instructor interests with evolving educational needs.


Assuntos
Biotecnologia/educação , Pesquisa , Animais , Cálcio/metabolismo , Clonagem Molecular , Currículo , Corantes Fluorescentes/química , Humanos , Proteínas/análise , Estudantes
7.
Biochem Mol Biol Educ ; 48(4): 381-390, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32585745

RESUMO

While it is essential for life science students to be trained in modern techniques and approaches, rapidly developing, interdisciplinary fields such as bioinformatics present distinct challenges to undergraduate educators. In particular, many educators lack training in new fields, and high-quality teaching and learning materials may be sparse. To address this challenge with respect to bioinformatics, the Network for the Integration of Bioinformatics into Life Science Education (NIBLSE), in partnership with Quantitative Undergraduate Biology Education and Synthesis (QUBES), developed incubators, a novel collaborative process for the development of open educational resources (OER). Incubators are short-term, online communities that refine unpublished teaching lessons into more polished and widely usable learning resources. The resulting products are published and made freely available in the NIBLSE Resource Collection, providing recognition of scholarly work by incubator participants. In addition to producing accessible, high-quality resources, incubators also provide opportunities for faculty development. Because participants are intentionally chosen to represent a range of expertise in bioinformatics and pedagogy, incubators also build professional connections among educators with diverse backgrounds and perspectives and promote the discussion of practical issues involved in deploying a resource in the classroom. Here we describe the incubator process and provide examples of beneficial outcomes. Our experience indicates that incubators are a low cost, short-term, flexible method for the development of OERs and professional community that could be adapted to a variety of disciplinary and pedagogical contexts.


Assuntos
Disciplinas das Ciências Biológicas/educação , Redes Comunitárias , Biologia Computacional/educação , Currículo/normas , Aprendizagem , Ensino/normas , Humanos , Estudantes
8.
Neurochem Int ; 138: 104772, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32464226

RESUMO

INTRODUCTION: A solid body of preclinical evidence shows that glucagon-like peptide-1 receptor (GLP-1R) agonists attenuate the effects of substance use disorder related behaviors. The mechanisms underlying these effects remain elusive. In the present study, we hypothesized that GLP-1R activation modulates dopaminetransporter (DAT) and thus dopamine (DA) homeostasis in striatum. This was evaluated in three different experiments: two preclinical and one clinical. METHODS: Rat striatal DA uptake, DA clearance and DAT cell surface expression was assessed following GLP-1 (7-36)-amide exposure in vitro. DA uptake in mice was assesed ex vivo following systemic treatment with the GLP-1R agonist exenatide. In addition, DA uptake was measured in GLP-1R knockout mice and compared with DA-uptake in wild type mice. In healthy humans, changes in DAT availability was assessed during infusion of exenatide measured by single-photon emission computed tomography imaging. RESULTS: In rats, GLP-1 (7-36)-amide increased DA uptake, DA clearance and DAT cell surface expression in striatum. In mice, exenatide did not change striatal DA uptake. In GLP-1R knockout mice, DA uptake was similar to what was measured in wildtype mice. In humans, systemic infusion of exenatide did not result in acute changes in striatal DAT availability. CONCLUSIONS: The GLP-1R agonist-induced modulation of striatal DAT activity in vitro in rats could not be replicated ex vivo in mice and in vivo in humans. Therefore, the underlying mechanisms of action for the GLP-1R agonists-induced efficacy in varios addiction-like behavioural models still remain.


Assuntos
Corpo Estriado/metabolismo , Proteínas da Membrana Plasmática de Transporte de Dopamina/metabolismo , Dopamina/metabolismo , Peptídeo 1 Semelhante ao Glucagon/metabolismo , Fragmentos de Peptídeos/metabolismo , Adolescente , Adulto , Animais , Corpo Estriado/efeitos dos fármacos , Antagonistas de Dopamina/farmacologia , Proteínas da Membrana Plasmática de Transporte de Dopamina/antagonistas & inibidores , Proteínas da Membrana Plasmática de Transporte de Dopamina/genética , Exenatida/farmacologia , Feminino , Peptídeo 1 Semelhante ao Glucagon/antagonistas & inibidores , Peptídeo 1 Semelhante ao Glucagon/genética , Humanos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Técnicas de Cultura de Órgãos , Fragmentos de Peptídeos/antagonistas & inibidores , Fragmentos de Peptídeos/genética , Ratos , Ratos Sprague-Dawley , Especificidade da Espécie , Tomografia Computadorizada de Emissão de Fóton Único/métodos , Adulto Jovem
9.
Artigo em Inglês | MEDLINE | ID: mdl-28861131

RESUMO

Metagenomics is an important method for studying microbial life. However, undergraduate exposure to metagenomics is hindered by associated software, computing demands, and dataset access. In this inquiry-based activity designed for introductory life science majors and nonmajors, students perform an investigation of the bacterial communities inhabiting the human belly button and associated metagenomics data collected through a citizen science project and visualized using an open-access bioinformatics tool. The activity is designed for attainment of the following student learning outcomes: defining terms associated with metagenomics analyses, describing the biological impact of the microbiota on human health, formulating a hypothesis, analyzing and interpreting metagenomics data to compare microbiota, evaluating a specific hypothesis, and synthesizing a conceptual model as to why bacterial populations vary. This activity was implemented in six introductory biology and biotechnology courses across five institutions. Attainment of student learning outcomes was assessed through completion of a quiz and students' presentations of their findings. In presentations, students demonstrated their ability to develop novel hypotheses and analyze and interpret metagenomic data to evaluate their hypothesis. In quizzes, students demonstrated their ability to define key terms and describe the biological impact of the microbiota on human health. Student learning gains assessment also revealed that students perceived gains for all student learning outcomes. Collectively, our assessment demonstrates achievement of the learning outcomes and supports the utility of this inquiry-based activity to engage undergraduates in the scientific process via analyses of metagenomics datasets and associated exploration of a microbial community that lives on the human body.

10.
Cell Rep ; 15(11): 2563-73, 2016 06 14.
Artigo em Inglês | MEDLINE | ID: mdl-27264177

RESUMO

Chemogenetic technologies, including the mutated human Gq-coupled M3 muscarinic receptor (hM3Dq), have greatly facilitated our ability to directly link changes in cellular activity to altered physiology and behavior. Here, we extend the hM3Dq toolkit with recombinase-responsive mouse lines that permit hM3Dq expression in virtually any cell type. These alleles encode a fusion protein designed to increase effective expression levels by concentrating hM3Dq to the cell body and dendrites. To illustrate their broad utility, we targeted three different genetically defined cell populations: noradrenergic neurons of the compact, bilateral locus coeruleus and two dispersed populations, Camk2a+ neurons and GFAP+ glia. In all three populations, we observed reproducible expression and confirmed that activation of hM3Dq is sufficient to dose-dependently evoke phenotypic changes, without extreme phenotypes associated with hM3Dq overexpression. These alleles offer the ability to non-invasively control activity of diverse cell types to uncover their function and dysfunction at any developmental stage.


Assuntos
Drogas Desenhadas/farmacologia , Técnicas Genéticas , Integrases/metabolismo , Receptor Muscarínico M3/genética , Alelos , Animais , Ansiedade/complicações , Ansiedade/patologia , Ansiedade/fisiopatologia , Comportamento Animal/efeitos dos fármacos , Clozapina , Dendritos/efeitos dos fármacos , Dendritos/metabolismo , Ritmo Gama/efeitos dos fármacos , Hipocampo/efeitos dos fármacos , Hipocampo/patologia , Hipocampo/fisiopatologia , Humanos , Hipotermia/complicações , Hipotermia/patologia , Hipotermia/fisiopatologia , Locomoção/efeitos dos fármacos , Camundongos , Neuroglia/efeitos dos fármacos , Neuroglia/metabolismo , Recombinação Genética/genética
11.
Brain Res ; 1641(Pt B): 234-44, 2016 06 15.
Artigo em Inglês | MEDLINE | ID: mdl-26612521

RESUMO

Uncovering the mechanisms that underlie central noradrenergic neuron heterogeneity is essential to understanding selective subtype vulnerability to disease and environmental insult. Using recombinase-based intersectional genetic fate mapping we have previously demonstrated that molecularly distinct progenitor populations give rise to mature noradrenergic neurons differing in their anatomical location, axon morphology and efferent projection pattern. Here we review the findings from our previous study and extend our analysis of the noradrenergic subpopulation defined by transient developmental expression of Hoxb1. Using a combination of intersectional genetic fate mapping and analysis of a targeted loss of function mutation in Hoxb1, we have now uncovered additional heterogeneity based on the requirement of some noradrenergic neurons for Hoxb1 expression. By comparing the distribution of noradrenergic neurons derived from the Hoxb1 expression domain in wild-type and mutant mice, we demonstrate that Hoxb1 expression is required by a subset of neurons in the pons. Additional fate mapping, using a Hoxb1 enhancer element that drives Cre recombinase expression exclusively in rhombomere 4 of the hindbrain, reveals the existence of a subpopulation of noradrenergic neurons in the pons with more restricted axonal targets than the full Hoxb1-derived subpopulation. The unique projection profile of this newly defined subpopulation suggests that it may be functionally distinct. These analyses shed new light on the molecular determinants of noradrenergic identity in the pons and the overall complexity of the central noradrenergic system. This article is part of a Special Issue entitled SI: Noradrenergic System.


Assuntos
Neurônios Adrenérgicos/citologia , Neurônios Adrenérgicos/fisiologia , Encéfalo/citologia , Encéfalo/crescimento & desenvolvimento , Animais , Encéfalo/fisiologia , Vias Neurais/citologia , Vias Neurais/crescimento & desenvolvimento , Vias Neurais/fisiologia
12.
Development ; 142(24): 4385-93, 2015 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-26586220

RESUMO

Investigating the developmental, structural and functional complexity of mammalian tissues and organs depends on identifying and gaining experimental access to diverse cell populations. Here, we describe a set of recombinase-responsive fluorescent indicator alleles in mice that significantly extends our ability to uncover cellular diversity by exploiting the intrinsic genetic signatures that uniquely define cell types. Using a recombinase-based intersectional strategy, these new alleles uniquely permit non-invasive labeling of cells defined by the overlap of up to three distinct gene expression domains. In response to different combinations of Cre, Flp and Dre recombinases, they express eGFP and/or tdTomato to allow the visualization of full cellular morphology. Here, we demonstrate the value of these features through a proof-of-principle analysis of the central noradrenergic system. We label previously inaccessible subpopulations of noradrenergic neurons to reveal details of their three-dimensional architecture and axon projection profiles. These new indicator alleles will provide experimental access to cell populations at unprecedented resolution, facilitating analysis of their developmental origin and anatomical, molecular and physiological properties.


Assuntos
Neurônios/citologia , Recombinases/metabolismo , Coloração e Rotulagem , Alelos , Animais , Axônios/metabolismo , Galinhas , Feminino , Corantes Fluorescentes/metabolismo , Expressão Gênica , Proteínas de Fluorescência Verde/metabolismo , Masculino , Camundongos , Neurônios/metabolismo
13.
Neurochem Int ; 73: 113-121, 2014 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-24090638

RESUMO

The serotonergic system regulates a wide range of behavior, including mood and impulsivity, and its dysregulation has been associated with mood disorders, autism spectrum disorder, and addiction. Diabetes is a risk factor for these conditions. Insulin resistance in the brain is specifically associated with susceptibility to psychostimulant abuse. Here, we examined whether phosphorylation of Akt, a key regulator of the insulin signaling pathway, controls serotonin (5-HT) signaling. To explore how impairment in Akt function regulates 5-HT homeostasis, we used a brain-specific rictor knockout (KO) mouse model of impaired neuronal phosphorylation of Akt at Ser473. Cortical 5-HT1A and 5-HT2A receptor binding was significantly elevated in rictor KO mice. Concomitant with this elevated receptor expression, the 5-HT1A receptor agonist 8-Hydroxy-2-(di-n-propylamino)tetralin (8-OH-DPAT) led to an increased hypothermic response in rictor KO mice. The increased cortical 5-HT1A receptor density was associated with higher 5-HT1A receptor levels on the cortical cell surface. In contrast, rictor KO mice displayed significantly reduced head-twitch response (HTR) to the 5-HT2A/C agonist 2,5-dimethoxy-4-iodoamphetamine (DOI), with evidence of impaired 5-HT2A/C receptor signaling. In vitro, pharmacological inhibition of Akt significantly increased 5-HT1A receptor expression and attenuated DOI-induced 5-HT2A receptor signaling, thereby lending credence to the observed in vivo cross-talk between neuronal Akt signaling and 5-HT receptor regulation. These data reveal that defective central Akt function alters 5-HT signaling as well as 5-HT-associated behaviors, demonstrating a novel role for Akt in maintaining neuronal 5-HT receptor function.


Assuntos
Neurônios/metabolismo , Proteína Oncogênica v-akt/genética , Receptor 5-HT1A de Serotonina/metabolismo , Receptor 5-HT2A de Serotonina/metabolismo , 8-Hidroxi-2-(di-n-propilamino)tetralina/farmacologia , Animais , Insulina/fisiologia , Sistema de Sinalização das MAP Quinases/efeitos dos fármacos , Sistema de Sinalização das MAP Quinases/genética , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Neurônios/fisiologia , Receptor 5-HT1A de Serotonina/efeitos dos fármacos , Receptor 5-HT2A de Serotonina/efeitos dos fármacos , Serotonina/metabolismo , Proteínas da Membrana Plasmática de Transporte de Serotonina/metabolismo , Agonistas do Receptor de Serotonina/farmacologia , Transdução de Sinais/genética , Transdução de Sinais/fisiologia
14.
Nat Neurosci ; 16(8): 1016-23, 2013 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-23852112

RESUMO

Central norepinephrine-producing neurons comprise a diverse population of cells differing in anatomical location, connectivity, function and response to disease and environmental insult. The mechanisms that generate this diversity are unknown. Here we elucidate the lineal relationship between molecularly distinct progenitor populations in the developing mouse hindbrain and mature norepinephrine neuron subtype identity. We have identified four genetically separable subpopulations of mature norepinephrine neurons differing in their anatomical location, axon morphology and efferent projection pattern. One of the subpopulations showed an unexpected projection to the prefrontal cortex, challenging the long-held belief that the locus coeruleus is the sole source of norepinephrine projections to the cortex. These findings reveal the embryonic origins of central norepinephrine neurons and provide multiple molecular points of entry for future study of individual norepinephrine circuits in complex behavioral and physiological processes including arousal, attention, mood, memory, appetite and homeostasis.


Assuntos
Neurônios Adrenérgicos/classificação , Neurogênese , Rombencéfalo/citologia , Fibras Adrenérgicas/fisiologia , Neurônios Adrenérgicos/citologia , Neurônios Adrenérgicos/enzimologia , Vias Aferentes , Animais , Axônios/ultraestrutura , Contagem de Células , Linhagem da Célula , Dopamina beta-Hidroxilase/análise , Feminino , Genes Reporter , Proteínas de Fluorescência Verde/biossíntese , Proteínas de Fluorescência Verde/genética , Locus Cerúleo/citologia , Locus Cerúleo/embriologia , Masculino , Camundongos , Proteínas do Tecido Nervoso/análise , Células-Tronco Neurais/citologia , Norepinefrina/fisiologia , Especificidade de Órgãos , Córtex Pré-Frontal/citologia , Córtex Pré-Frontal/embriologia , Proteínas Recombinantes de Fusão/biossíntese , Proteínas Recombinantes de Fusão/genética , Rombencéfalo/embriologia
15.
Neuropharmacology ; 61(7): 1123-8, 2011 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-21420985

RESUMO

Across species, the brain evolved to respond to natural rewards such as food and sex. These physiological responses are important for survival, reproduction and evolutionary processes. It is no surprise, therefore, that many of the neural circuits and signaling pathways supporting reward processes are conserved from Caenorhabditis elegans to Drosophilae, to rats, monkeys and humans. The central role of dopamine (DA) in encoding reward and in attaching salience to external environmental cues is well recognized. Less widely recognized is the role of reporters of the "internal environment", particularly insulin, in the modulation of reward. Insulin has traditionally been considered an important signaling molecule in regulating energy homeostasis and feeding behavior rather than a major component of neural reward circuits. However, research over recent decades has revealed that DA and insulin systems do not operate in isolation from each other, but instead, work together to orchestrate both the motivation to engage in consummatory behavior and to calibrate the associated level of reward. Insulin signaling has been found to regulate DA neurotransmission and to affect the ability of drugs that target the DA system to exert their neurochemical and behavioral effects. Given that many abused drugs target the DA system, the elucidation of how dopaminergic, as well as other brain reward systems, are regulated by insulin will create opportunities to develop therapies for drug and potentially food addiction. Moreover, a more complete understanding of the relationship between DA neurotransmission and insulin may help to uncover etiological bases for "food addiction" and the growing epidemic of obesity. This review focuses on the role of insulin signaling in regulating DA homeostasis and DA signaling, and the potential impact of impaired insulin signaling in obesity and psychostimulant abuse.


Assuntos
Comportamento Aditivo/metabolismo , Insulina/metabolismo , Receptor de Insulina/metabolismo , Transdução de Sinais , Animais , Encéfalo/metabolismo , Dopamina/metabolismo , Humanos , Resistência à Insulina , Neurônios/metabolismo , Obesidade/metabolismo
16.
Nat Neurosci ; 14(4): 469-77, 2011 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-21399631

RESUMO

Plasmalemmal neurotransmitter transporters (NTTs) regulate the level of neurotransmitters, such as dopamine (DA) and glutamate, after their release at brain synapses. Stimuli including protein kinase C (PKC) activation can lead to the internalization of some NTTs and a reduction in neurotransmitter clearance capacity. We found that the protein Flotillin-1 (Flot1), also known as Reggie-2, was required for PKC-regulated internalization of members of two different NTT families, the DA transporter (DAT) and the glial glutamate transporter EAAT2, and we identified a conserved serine residue in Flot1 that is essential for transporter internalization. Further analysis revealed that Flot1 was also required to localize DAT within plasma membrane microdomains in stable cell lines, and was essential for amphetamine-induced reverse transport of DA in neurons but not for DA uptake. In sum, our findings provide evidence for a critical role of Flot1-enriched membrane microdomains in PKC-triggered DAT endocytosis and the actions of amphetamine.


Assuntos
Proteínas da Membrana Plasmática de Transporte de Dopamina/metabolismo , Endocitose/fisiologia , Microdomínios da Membrana/metabolismo , Proteínas de Membrana/fisiologia , Proteína Quinase C/fisiologia , Animais , Endocitose/efeitos dos fármacos , Transportador 2 de Aminoácido Excitatório/metabolismo , Transportador 2 de Aminoácido Excitatório/fisiologia , Células HEK293 , Células HeLa , Humanos , Camundongos , Neuroglia/metabolismo
17.
J Neurosci ; 30(34): 11305-16, 2010 Aug 25.
Artigo em Inglês | MEDLINE | ID: mdl-20739551

RESUMO

Noradrenergic signaling in the CNS plays an essential role in circuits involving attention, mood, memory, and stress as well as providing pivotal support for autonomic function in the peripheral nervous system. The high-affinity norepinephrine (NE) transporter (NET) is the primary mechanism by which noradrenergic synaptic transmission is terminated. Data indicate that NET function is regulated by insulin, a hormone critical for the regulation of metabolism. Given the high comorbidity of metabolic disorders such as diabetes and obesity with mental disorders such as depression and schizophrenia, we sought to determine how insulin signaling regulates NET function and thus noradrenergic homeostasis. Here, we show that acute insulin treatment, through the downstream kinase protein kinase B (Akt), significantly decreases NET surface expression in mouse hippocampal slices and superior cervical ganglion neuron boutons (sites of synaptic NE release). In vivo manipulation of insulin/Akt signaling, with streptozotocin, a drug that induces a type 1-like diabetic state in mice, also results in aberrant NET function and NE homeostasis. Notably, we also demonstrate that Akt inhibition or stimulation, independent of insulin, is capable of altering NET surface availability. These data suggest that aberrant states of Akt signaling such as in diabetes and obesity have the potential to alter NET function and noradrenergic tone in the brain. Furthermore, they provide one potential molecular mechanism by which Akt, a candidate gene for mood disorders such as schizophrenia and depression, can impact brain monoamine homeostasis.


Assuntos
Homeostase/fisiologia , Insulina/fisiologia , Proteínas da Membrana Plasmática de Transporte de Norepinefrina/metabolismo , Norepinefrina/fisiologia , Proteínas Proto-Oncogênicas c-akt/fisiologia , Transdução de Sinais/fisiologia , Animais , Células CHO , Células Cultivadas , Cricetinae , Cricetulus , Humanos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Transporte Proteico/fisiologia
18.
PLoS Biol ; 8(6): e1000393, 2010 Jun 08.
Artigo em Inglês | MEDLINE | ID: mdl-20543991

RESUMO

The mammalian target of rapamycin (mTOR) complex 2 (mTORC2) is a multimeric signaling unit that phosphorylates protein kinase B/Akt following hormonal and growth factor stimulation. Defective Akt phosphorylation at the mTORC2-catalyzed Ser473 site has been linked to schizophrenia. While human imaging and animal studies implicate a fundamental role for Akt signaling in prefrontal dopaminergic networks, the molecular mechanisms linking Akt phosphorylation to specific schizophrenia-related neurotransmission abnormalities have not yet been described. Importantly, current understanding of schizophrenia suggests that cortical decreases in DA neurotransmission and content, defined here as cortical hypodopaminergia, contribute to both the cognitive deficits and the negative symptoms characteristic of this disorder. We sought to identify a mechanism linking aberrant Akt signaling to these hallmarks of schizophrenia. We used conditional gene targeting in mice to eliminate the mTORC2 regulatory protein rictor in neurons, leading to impairments in neuronal Akt Ser473 phosphorylation. Rictor-null (KO) mice exhibit prepulse inhibition (PPI) deficits, a schizophrenia-associated behavior. In addition, they show reduced prefrontal dopamine (DA) content, elevated cortical norepinephrine (NE), unaltered cortical serotonin (5-HT), and enhanced expression of the NE transporter (NET). In the cortex, NET takes up both extracellular NE and DA. Thus, we propose that amplified NET function in rictor KO mice enhances accumulation of both NE and DA within the noradrenergic neuron. This phenomenon leads to conversion of DA to NE and ultimately supports both increased NE tissue content as well as a decrease in DA. In support of this hypothesis, NET blockade in rictor KO mice reversed cortical deficits in DA content and PPI, suggesting that dysregulation of DA homeostasis is driven by alteration in NET expression, which we show is ultimately influenced by Akt phosphorylation status. These data illuminate a molecular link, Akt regulation of NET, between the recognized association of Akt signaling deficits in schizophrenia with a specific mechanism for cortical hypodopaminergia and hypofunction. Additionally, our findings identify Akt as a novel modulator of monoamine homeostasis in the cortex.


Assuntos
Proteínas de Transporte/fisiologia , Dopamina/metabolismo , Proteínas da Membrana Plasmática de Transporte de Norepinefrina/fisiologia , Córtex Pré-Frontal/metabolismo , Esquizofrenia/fisiopatologia , Animais , Proteínas de Transporte/genética , Camundongos , Camundongos Knockout , Fosforilação , Proteínas Proto-Oncogênicas c-akt/química , Proteínas Proto-Oncogênicas c-akt/metabolismo , Proteína Companheira de mTOR Insensível à Rapamicina , Serina/metabolismo , Transdução de Sinais , Transativadores/metabolismo , Fatores de Transcrição
19.
Mol Pharmacol ; 74(4): 1101-8, 2008 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-18617632

RESUMO

The soluble N-ethylmaleimide-sensitive factor attachment protein receptor protein syntaxin 1A (SYN1A) interacts with and regulates the function of transmembrane proteins, including ion channels and neurotransmitter transporters. Here, we define the first 33 amino acids of the N terminus of the dopamine (DA) transporter (DAT) as the site of direct interaction with SYN1A. Amphetamine (AMPH) increases the association of SYN1A with human DAT (hDAT) in a heterologous expression system (hDAT cells) and with native DAT in murine striatal synaptosomes. Immunoprecipitation of DAT from the biotinylated fraction shows that the AMPH-induced increase in DAT/SYN1A association occurs at the plasma membrane. In a superfusion assay of DA efflux, cells overexpressing SYN1A exhibited significantly greater AMPH-induced DA release with respect to control cells. By combining the patch-clamp technique with amperometry, we measured DA release under voltage clamp. At -60 mV, a physiological resting potential, AMPH did not induce DA efflux in hDAT cells and DA neurons. In contrast, perfusion of exogenous SYN1A (3 microM) into the cell with the whole-cell pipette enabled AMPH-induced DA efflux at -60 mV in both hDAT cells and DA neurons. It has been shown recently that Ca2+/calmodulin-dependent protein kinase II (CaMKII) is activated by AMPH and regulates AMPH-induced DA efflux. Here, we show that AMPH-induced association between DAT and SYN1A requires CaMKII activity and that inhibition of CaMKII blocks the ability of exogenous SYN1A to promote DA efflux. These data suggest that AMPH activation of CaMKII supports DAT/SYN1A association, resulting in a mode of DAT capable of DA efflux.


Assuntos
Anfetamina/farmacologia , Proteínas da Membrana Plasmática de Transporte de Dopamina/metabolismo , Dopamina/metabolismo , Sintaxina 1/metabolismo , Sequência de Aminoácidos , Animais , Linhagem Celular , Membrana Celular/metabolismo , Células Cultivadas , Corpo Estriado/citologia , Proteínas da Membrana Plasmática de Transporte de Dopamina/química , Proteínas da Membrana Plasmática de Transporte de Dopamina/genética , Glutationa Transferase/metabolismo , Humanos , Rim/citologia , Mesencéfalo/citologia , Camundongos , Camundongos Transgênicos , Dados de Sequência Molecular , Neurônios/citologia , Neurônios/metabolismo , Proteínas Recombinantes de Fusão/química , Proteínas Recombinantes de Fusão/metabolismo , Sinaptossomos/metabolismo , Transfecção
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