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1.
Complex Psychiatry ; 8(3-4): 80-89, 2023 Jan.
Article in English | MEDLINE | ID: mdl-36660008

ABSTRACT

Introduction: Sexual assault is an urgent public health concern with both immediate and long-lasting health consequences, affecting 44% of women and 25% of men during their lifetimes. Large studies are needed to understand the unique healthcare needs of this patient population. Methods: We mined clinical notes to identify patients with a history of sexual assault in the electronic health record (EHR) at Vanderbilt University Medical Center (VUMC), a large university hospital in the Southeastern USA, from 1989 to 2021 (N = 3,376,424). Using a phenome-wide case-control study, we identified diagnoses co-occurring with disclosures of sexual assault. We performed interaction tests to examine whether sex modified any of these associations. Association analyses were restricted to a subset of patients receiving regular care at VUMC (N = 833,185). Results: The phenotyping approach identified 14,496 individuals (0.43%) across the VUMC-EHR with documentation of sexual assault and achieved a positive predictive value of 93.0% (95% confidence interval = 85.6-97.0%), determined by manual patient chart review. Out of 1,703 clinical diagnoses tested across all subgroup analyses, 465 were associated with sexual assault. Sex-by-trauma interaction analysis revealed 55 sex-differential associations and demonstrated increased odds of psychiatric diagnoses in male survivors. Discussion: This case-control study identified associations between disclosures of sexual assault and hundreds of health conditions, many of which demonstrated sex-differential effects. The findings of this study suggest that patients who have experienced sexual assault are at risk for developing wide-ranging medical and psychiatric comorbidities and that male survivors may be particularly vulnerable to developing mental illness.

2.
Cell Rep ; 41(3): 111474, 2022 10 18.
Article in English | MEDLINE | ID: mdl-36261025

ABSTRACT

Within eukaryotic cells, translation is regulated independent of transcription, enabling nuanced, localized, and rapid responses to stimuli. Neurons respond transcriptionally and translationally to synaptic activity. Although transcriptional responses are documented in astrocytes, here we test whether astrocytes have programmed translational responses. We show that seizure activity rapidly changes the transcripts on astrocyte ribosomes, some predicted to be downstream of BDNF signaling. In acute slices, we quantify the extent to which cues of neuronal activity activate translation in astrocytes and show that this translational response requires the presence of neurons, indicating that the response is non-cell autonomous. We also show that this induction of new translation extends into the periphery of astrocytes. Finally, synaptic proteomics show that new translation is required for changes that occur in perisynaptic astrocyte protein composition after fear conditioning. Regulation of translation in astrocytes by neuronal activity suggests an additional mechanism by which astrocytes may dynamically modulate nervous system functioning.


Subject(s)
Astrocytes , Proteome , Brain-Derived Neurotrophic Factor , Cell Membrane Structures , Proteomics
3.
Brain Imaging Behav ; 15(2): 1007-1024, 2021 Apr.
Article in English | MEDLINE | ID: mdl-32740888

ABSTRACT

Externalizing psychopathology (EXT) is characterized by poor decision-making in situations that involve simultaneous cues for approach and avoidance behavior (i.e. approach-avoidance conflicts). Previous studies of EXT have examined these deficits primarily using tasks involving decisions between positive reward and negative punishment, suggesting that EXT is characterized by a general bias towards high salience (e.g. temporally proximal or reward) cues relative to low salience (e.g. temporally distal or loss) cues. However, in order to better characterize decision-making in approach-avoidance conflicts, the present study utilized a novel task to examine neural activation in contexts involving both positive reward and negative punishment as well as positive punishment and negative reward by manipulating physical proximity of affective cues. Neuroimaging results indicated that EXT was associated with deficits related to cue prioritization based on salience, suggesting that failure to differentiate relevant from less relevant information contributes to poor decision-making among individuals with EXT.


Subject(s)
Decision Making , Psychopathology , Cues , Humans , Magnetic Resonance Imaging , Reward
4.
JAMA Netw Open ; 3(12): e2027920, 2020 12 01.
Article in English | MEDLINE | ID: mdl-33372972

ABSTRACT

Importance: Functional seizures (formerly psychogenic nonepileptic seizures), paroxysmal episodes that are often similar to epileptic seizures in their clinical presentation and display no aberrant brain electrical patterns, are understudied. Patients experience a long diagnostic delay, few treatment modalities, a high rate of comorbidities, and significant stigma due to the lack of knowledge about functional seizures. Objective: To characterize the clinical epidemiology of a population of patients with functional seizures observed at Vanderbilt University Medical Center (VUMC). Design, Setting, and Participants: This case-control study included patients with functional seizures identified in the VUMC electronic health record (VUMC-EHR) system from October 1989 to October 2018. Patients with epilepsy were excluded from the study and all remaining patients in the VUMC medical center system were used as controls. In total, the study included 1431 patients diagnosed with functional seizures, 2251 with epilepsy and functional seizures, 4715 with epilepsy without functional seizures, and 502 200 control patients who received treatment at VUMC for a minimum of a 3 years. Data were analyzed from November 2018 to March 2020. Exposure: Diagnosis of functional seizures, as identified from the VUMC-EHR system by an automated phenotyping algorithm that incorporated International Classification of Diseases, Ninth Revision (ICD-9) codes, International Statistical Classification of Diseases and Related Health Problems, Tenth Revision (ICD-10) codes, Current Procedural Terminology codes, and natural language processing. Main Outcomes and Measures: Associations of functional seizures with comorbidities and risk factors, measured in odds ratios (ORs). Results: Of 2 346 808 total patients in the VUMC-EHR aged 18 years or older, 3341 patients with functional seizures were identified (period prevalence, 0.14%), 1062 (74.2%) of whom were women and for which the median (interquartile range) age was 49.3 (39.4-59.9) years. This assessment replicated previously reported associations with psychiatric disorders including posttraumatic stress disorder (PTSD) (OR, 1.22; 95% CI, 1.21-1.24; P < 3.02 × 10-5), anxiety (OR, 1.14; 95% CI, 1.13-1.15; P < 3.02 × 10-5), and depression (OR, 1.14; 95% CI, 1.13-1.15; P < 3.02 × 10-5), and identified novel associations with cerebrovascular disease (OR, 1.08; 95% CI, 1.06-1.09; P < 3.02 × 10-5). An association was found between functional seizures and the known risk factor sexual assault trauma (OR, 10.26; 95% CI, 10.09-10.44; P < 3.02 × 10-5), and sexual assault trauma was found to mediate nearly a quarter of the association between female sex and functional seizures in the VUMC-EHR. Conclusions and Relevance: This case-control study found evidence to support previously reported associations, discovered new associations between functional seizures and PTSD, anxiety, and depression. An association between cerebrovascular disease and functional seizures was also found. Results suggested that sexual trauma may be a mediating factor in the association between female sex and functional seizures.


Subject(s)
Mental Disorders/epidemiology , Seizures/epidemiology , Adult , Anxiety/epidemiology , Case-Control Studies , Comorbidity , Delayed Diagnosis , Depression/epidemiology , Female , Hospitals, University/statistics & numerical data , Humans , Male , Middle Aged , Odds Ratio , Risk Factors , Seizures/etiology , Seizures/psychology , Stress Disorders, Post-Traumatic/epidemiology
5.
Acta Neuropathol ; 139(1): 45-61, 2020 01.
Article in English | MEDLINE | ID: mdl-31456032

ABSTRACT

Apart from amyloid ß deposition and tau neurofibrillary tangles, Alzheimer's disease (AD) is a neurodegenerative disorder characterized by neuronal loss and astrocytosis in the cerebral cortex. The goal of this study is to investigate genetic factors associated with the neuronal proportion in health and disease. To identify cell-autonomous genetic variants associated with neuronal proportion in cortical tissues, we inferred cellular population structure from bulk RNA-Seq derived from 1536 individuals. We identified the variant rs1990621 located in the TMEM106B gene region as significantly associated with neuronal proportion (p value = 6.40 × 10-07) and replicated this finding in an independent dataset (p value = 7.41 × 10-04) surpassing the genome-wide threshold in the meta-analysis (p value = 9.42 × 10-09). This variant is in high LD with the TMEM106B non-synonymous variant p.T185S (rs3173615; r2 = 0.98) which was previously identified as a protective variant for frontotemporal lobar degeneration (FTLD). We stratified the samples by disease status, and discovered that this variant modulates neuronal proportion not only in AD cases, but also several neurodegenerative diseases and in elderly cognitively healthy controls. Furthermore, we did not find a significant association in younger controls or schizophrenia patients, suggesting that this variant might increase neuronal survival or confer resilience to the neurodegenerative process. The single variant and gene-based analyses also identified an overall genetic association between neuronal proportion, AD and FTLD risk. These results suggest that common pathways are implicated in these neurodegenerative diseases, that implicate neuronal survival. In summary, we identified a protective variant in the TMEM106B gene that may have a neuronal protection effect against general aging, independent of disease status, which could help elucidate the relationship between aging and neuronal survival in the presence or absence of neurodegenerative disorders. Our findings suggest that TMEM106B could be a potential target for neuronal protection therapies to ameliorate cognitive and functional deficits.


Subject(s)
Aging/genetics , Brain , Genetic Predisposition to Disease/genetics , Membrane Proteins/genetics , Nerve Tissue Proteins/genetics , Neurodegenerative Diseases/genetics , Neurons , Aged , Aged, 80 and over , Brain/metabolism , Brain/pathology , Female , Humans , Male , Neurons/metabolism , Neurons/pathology , Polymorphism, Single Nucleotide
6.
Cell Rep ; 26(3): 594-607.e7, 2019 01 15.
Article in English | MEDLINE | ID: mdl-30650354

ABSTRACT

Alternative translation initiation and stop codon readthrough in a few well-studied cases have been shown to allow the same transcript to generate multiple protein variants. Because the brain shows a particularly abundant use of alternative splicing, we sought to study alternative translation in CNS cells. We show that alternative translation is widespread and regulated across brain transcripts. In neural cultures, we identify alternative initiation on hundreds of transcripts, confirm several N-terminal protein variants, and show the modulation of the phenomenon by KCl stimulation. We also detect readthrough in cultures and show differential levels of normal and readthrough versions of AQP4 in gliotic diseases. Finally, we couple translating ribosome affinity purification to ribosome footprinting (TRAP-RF) for cell-type-specific analysis of neuronal and astrocytic translational readthrough in the mouse brain. We demonstrate that this unappreciated mechanism generates numerous and diverse protein isoforms in a cell-type-specific manner in the brain.


Subject(s)
Brain/metabolism , Protein Isoforms/metabolism , Proteomics/methods , Animals , Brain/pathology , Mice
7.
Nat Genet ; 51(1): 106-116, 2019 01.
Article in English | MEDLINE | ID: mdl-30559488

ABSTRACT

We combined de novo mutation (DNM) data from 10,927 individuals with developmental delay and autism to identify 253 candidate neurodevelopmental disease genes with an excess of missense and/or likely gene-disruptive (LGD) mutations. Of these genes, 124 reach exome-wide significance (P < 5 × 10-7) for DNM. Intersecting these results with copy number variation (CNV) morbidity data shows an enrichment for genomic disorder regions (30/253, likelihood ratio (LR) +1.85, P = 0.0017). We identify genes with an excess of missense DNMs overlapping deletion syndromes (for example, KIF1A and the 2q37 deletion) as well as duplication syndromes, such as recurrent MAPK3 missense mutations within the chromosome 16p11.2 duplication, recurrent CHD4 missense DNMs in the 12p13 duplication region, and recurrent WDFY4 missense DNMs in the 10q11.23 duplication region. Network analyses of genes showing an excess of DNMs highlights functional networks, including cell-specific enrichments in the D1+ and D2+ spiny neurons of the striatum.


Subject(s)
DNA Copy Number Variations/genetics , Mutation/genetics , Neurodevelopmental Disorders/genetics , Animals , Autistic Disorder/genetics , Chromosome Aberrations , Developmental Disabilities/genetics , Exome/genetics , Humans , Intellectual Disability/genetics , Intracellular Signaling Peptides and Proteins/genetics , Mi-2 Nucleosome Remodeling and Deacetylase Complex/genetics , Mice , Phenotype , Polymorphism, Single Nucleotide/genetics
8.
Brain ; 141(9): 2561-2575, 2018 09 01.
Article in English | MEDLINE | ID: mdl-30007309

ABSTRACT

We recently demonstrated that microRNA-218 (miR-218) is greatly enriched in motor neurons and is released extracellularly in amyotrophic lateral sclerosis model rats. To determine if the released, motor neuron-derived miR-218 may have a functional role in amyotrophic lateral sclerosis, we examined the effect of miR-218 on neighbouring astrocytes. Surprisingly, we found that extracellular, motor neuron-derived miR-218 can be taken up by astrocytes and is sufficient to downregulate an important glutamate transporter in astrocytes [excitatory amino acid transporter 2 (EAAT2)]. The effect of miR-218 on astrocytes extends beyond EAAT2 since miR-218 binding sites are enriched in mRNAs translationally downregulated in amyotrophic lateral sclerosis astrocytes. Inhibiting miR-218 with antisense oligonucleotides in amyotrophic lateral sclerosis model mice mitigates the loss of EAAT2 and other miR-218-mediated changes, providing an important in vivo demonstration of the relevance of microRNA-mediated communication between neurons and astrocytes. These data define a novel mechanism in neurodegeneration whereby microRNAs derived from dying neurons can directly modify the glial phenotype and cause astrocyte dysfunction.


Subject(s)
Amyotrophic Lateral Sclerosis/genetics , Astrocytes/physiology , MicroRNAs/metabolism , Amino Acid Transport System X-AG/genetics , Amino Acid Transport System X-AG/physiology , Animals , Astrocytes/metabolism , Cells, Cultured , Disease Models, Animal , Down-Regulation , Excitatory Amino Acid Transporter 2/genetics , Excitatory Amino Acid Transporter 2/physiology , Glutamic Acid/metabolism , HEK293 Cells , Humans , Mice , Mice, Inbred C57BL , MicroRNAs/genetics , MicroRNAs/physiology , Motor Neurons/metabolism , Motor Neurons/physiology , Neuroglia/metabolism
9.
Cell Rep ; 23(8): 2225-2235, 2018 05 22.
Article in English | MEDLINE | ID: mdl-29791834

ABSTRACT

Preclinical work has long focused on male animals, though biological sex clearly influences risk for certain diseases, including many psychiatric disorders. Such disorders are often treated by drugs targeting the CNS norepinephrine system. Despite roles for noradrenergic neurons in behavior and neuropsychiatric disease models, their molecular characterization has lagged. We profiled mouse noradrenergic neurons in vivo, defining over 3,000 high-confidence transcripts expressed therein, including druggable receptors. We uncovered remarkable sex differences in gene expression, including elevated expression of the EP3 receptor in females-which we leverage to illustrate the behavioral and pharmacologic relevance of these findings-and of Slc6a15 and Lin28b, both major depressive disorder (MDD)-associated genes. Broadly, we present a means of transcriptionally profiling locus coeruleus under baseline and experimental conditions. Our findings underscore the need for preclinical work to include both sexes and suggest that sex differences in noradrenergic neurons may underlie behavioral differences relevant to disease.


Subject(s)
Adrenergic Neurons/metabolism , Locus Coeruleus/metabolism , Sex Characteristics , Animals , Behavior, Animal , Female , Gene Expression Regulation , Lipopolysaccharides , Male , Mice , Norepinephrine Plasma Membrane Transport Proteins/metabolism , Protein Biosynthesis , RNA, Messenger/genetics , RNA, Messenger/metabolism , Receptors, Prostaglandin E, EP3 Subtype/metabolism , Reproducibility of Results , Ribosomes/metabolism , Transcription, Genetic
10.
Alcohol Alcohol ; 53(3): 209-215, 2018 May 01.
Article in English | MEDLINE | ID: mdl-29329417

ABSTRACT

Growing evidence suggests that glutamate neurotransmission plays a critical role in alcohol addiction. Cue-induced change of glutamate has been observed in animal studies but never been investigated in humans. This work investigates cue-induced change in forebrain glutamate in individuals with alcohol use disorder (AUD). A total of 35 subjects (17 individuals with AUD and 18 healthy controls) participated in this study. The glutamate concentration was measured with single-voxel 1H-MR spectroscopy at the dorsal anterior cingulate. Two MRS sessions were performed in succession, the first to establish basal glutamate levels and the second to measure the change in response to alcohol cues. The changes in glutamate were quantified for both AUD subjects and controls. A mixed model ANOVA and t-tests were performed for statistical analysis. ANOVA revealed a main effect of cue-induced decrease of glutamate level in the anterior cingulate cortex (ACC). A significant interaction revealed that only AUD subjects showed significant decrease of glutamate in the ACC. There were no significant group differences in the level of basal glutamate. However, a negative correlation was found between the basal glutamate level and the number of drinking days in the past 2 weeks for the AUD subjects. Collectively, our results indicate that glutamate in key areas of the forebrain reward circuit is modulated by alcohol cues in early alcohol dependence.


Subject(s)
Alcohol Drinking/metabolism , Alcoholism/metabolism , Cues , Glutamic Acid/metabolism , Gyrus Cinguli/metabolism , Magnetic Resonance Spectroscopy/methods , Adult , Alcohol Drinking/psychology , Alcoholism/diagnosis , Alcoholism/psychology , Female , Humans , Male , Photic Stimulation/methods , Young Adult
11.
Alcohol ; 66: 9-14, 2018 02.
Article in English | MEDLINE | ID: mdl-29277285

ABSTRACT

Executive working memory capacity (eWMC) is central to adaptive decision-making. Research has revealed reduced eWMC and higher rates of impulsive decision making in individuals with alcohol use disorders (AUDs: DSM-IV Alcohol Dependence of Alcohol Abuse) and antisocial psychopathology (AP). Recent work has shown that placing a load on working memory (WM) further increases impulsive decision making on the delay discounting (DD) task in those with AUDs and AP. The current study examined the effects of an attention refocusing manipulation to offset the effects of this WM-load on DD rates in control subjects, those with AUDs without AP, and AUDs with AP (AUD-AP). Results revealed that 1) the AUD-AP group had higher DD rates (i.e., more impulsive decision-making) than the AUD group, followed by controls, and 2) attention refocusing after a load is placed on WM was associated with lower DD rates compared to the load without refocusing in both AUD groups, but not controls. Results suggest that refocusing attention after a cognitive load may be an effective cognitive strategy for reducing the impulsivity-enhancing effects of cognitive load on decision making in individuals with AUDs and AP.


Subject(s)
Alcoholism/psychology , Antisocial Personality Disorder/psychology , Attention , Brain/physiopathology , Executive Function , Memory, Short-Term , Personality , Adult , Alcoholism/diagnosis , Alcoholism/physiopathology , Antisocial Personality Disorder/diagnosis , Antisocial Personality Disorder/physiopathology , Case-Control Studies , Cognition , Female , Humans , Impulsive Behavior , Male , Reaction Time , Time Factors , Young Adult
12.
eNeuro ; 5(6)2018.
Article in English | MEDLINE | ID: mdl-30723792

ABSTRACT

Local translation in neurites is a phenomenon that enhances the spatial segregation of proteins and their functions away from the cell body, yet it is unclear how local translation varies across neuronal cell types. Further, it is unclear whether differences in local translation across cell types simply reflect differences in transcription or whether there is also a cell type-specific post-transcriptional regulation of the location and translation of specific mRNAs. Most of the mRNAs discovered as being locally translated have been identified from hippocampal neurons because their laminar organization facilitates neurite-specific dissection and microscopy methods. Given the diversity of neurons across the brain, studies have not yet analyzed how locally translated mRNAs differ across cell types. Here, we used the SynapTRAP method to harvest two broad cell types in the mouse forebrain: GABAergic neurons and layer 5 projection neurons. While some transcripts overlap, the majority of the local translatome is not shared across these cell types. In addition to differences driven by baseline expression levels, some transcripts also exhibit cell type-specific post-transcriptional regulation. Finally, we provide evidence that GABAergic neurons specifically localize mRNAs for peptide neurotransmitters, including somatostatin and cortistatin, suggesting localized production of these key signaling molecules in the neurites of GABAergic neurons. Overall, this work suggests that differences in local translation in neurites across neuronal cell types are poised to contribute substantially to the heterogeneity in neuronal phenotypes.


Subject(s)
GABAergic Neurons/metabolism , Neurites/metabolism , Peptide Chain Termination, Translational/physiology , Pyramidal Cells/metabolism , RNA Processing, Post-Transcriptional/physiology , RNA, Messenger/metabolism , Animals , Cerebral Cortex/cytology , GABAergic Neurons/ultrastructure , Gene Ontology , Green Fluorescent Proteins/genetics , Green Fluorescent Proteins/metabolism , Mice , Mice, Transgenic , Prosencephalon/cytology , Pyramidal Cells/ultrastructure , Retinol-Binding Proteins, Plasma/genetics , Retinol-Binding Proteins, Plasma/metabolism , Tartrate-Resistant Acid Phosphatase/genetics , Tartrate-Resistant Acid Phosphatase/metabolism , Vesicular Inhibitory Amino Acid Transport Proteins/genetics , Vesicular Inhibitory Amino Acid Transport Proteins/metabolism
13.
Curr Opin Syst Biol ; 3: 67-76, 2017 Jun.
Article in English | MEDLINE | ID: mdl-29057378

ABSTRACT

As recent advances in human genetics have begun to more rapidly identify the individual genes contributing to risk of psychiatric disease, the spotlight now turns to understanding how disruption of these genes alters the brain, and thus behavior. Compared to other tissues, cellular complexity in the brain provides both a substantial challenge and a significant opportunity for systems biology approaches. Current methods are maturing that will allow for finally defining the 'parts list' for the functioning mouse and human brains, enabling new approaches to defining how the system goes awry in disorders of the CNS. However, the availability of tissue is certainly a challenge for systems biology of neuroscience, compared to systems biology of other tissues, where biopsy is feasible. This challenge is particularly notable for disorders caused by extremely rare genetic variants. Thus computational and systems biology approaches, as well as precise experimental models by way of genome editing, will play key roles in defining mechanisms for disorders, and their individual symptoms, across varied genetic etiologies. Here, we highlight recent progress in neurogenetics, postmortem genomics, cell-type specific profiling, and precision modeling toward defining mechanisms in disease.

14.
Cell Stem Cell ; 21(3): 332-348.e9, 2017 09 07.
Article in English | MEDLINE | ID: mdl-28886366

ABSTRACT

Directed reprogramming of human fibroblasts into fully differentiated neurons requires massive changes in epigenetic and transcriptional states. Induction of a chromatin environment permissive for acquiring neuronal subtype identity is therefore a major barrier to fate conversion. Here we show that the brain-enriched miRNAs miR-9/9∗ and miR-124 (miR-9/9∗-124) trigger reconfiguration of chromatin accessibility, DNA methylation, and mRNA expression to induce a default neuronal state. miR-9/9∗-124-induced neurons (miNs) are functionally excitable and uncommitted toward specific subtypes but possess open chromatin at neuronal subtype-specific loci, suggesting that such identity can be imparted by additional lineage-specific transcription factors. Consistently, we show that ISL1 and LHX3 selectively drive conversion to a highly homogeneous population of human spinal cord motor neurons. This study shows that modular synergism between miRNAs and neuronal subtype-specific transcription factors can drive lineage-specific neuronal reprogramming, providing a general platform for high-efficiency generation of distinct subtypes of human neurons.


Subject(s)
Cellular Reprogramming , Chromatin/metabolism , Fibroblasts/cytology , MicroRNAs/metabolism , Neurons/cytology , Adult , Cell Lineage/genetics , Cells, Cultured , Cellular Reprogramming/genetics , Chromatin Assembly and Disassembly/genetics , DNA Methylation/genetics , Electrophysiological Phenomena , Epigenesis, Genetic , Gene Expression Profiling , Heterochromatin/metabolism , Humans , MicroRNAs/genetics , Motor Neurons/cytology , Motor Neurons/metabolism , Neurogenesis/genetics , Neurons/metabolism , Spinal Cord/cytology , Time Factors , Transcription, Genetic , Transcriptional Activation/genetics
15.
J Neurosci ; 37(36): 8688-8705, 2017 09 06.
Article in English | MEDLINE | ID: mdl-28821669

ABSTRACT

Localized translation in neurites helps regulate synaptic strength and development. Dysregulation of local translation is associated with many neurological disorders. However, due to technical limitations, study of this phenomenon has largely been limited to brain regions with laminar organization of dendrites such as the hippocampus or cerebellum. It has not been examined in the cortex, a region of importance for most neurological disorders, where dendrites of each neuronal population are densely intermingled with cell bodies of others. Therefore, we have developed a novel method, SynapTRAP, which combines synaptoneurosomal fractionation with translating ribosome affinity purification to identify ribosome-bound mRNA in processes of genetically defined cell types. We demonstrate SynapTRAP's efficacy and report local translation in the cortex of mice, where we identify a subset of mRNAs that are translated in dendrites by neuronal ribosomes. These mRNAs have disproportionately longer lengths, enrichment for FMRP binding and G-quartets, and their genes are under greater evolutionary constraint in humans. In addition, we show that alternative splicing likely regulates this phenomenon. Overall, SynapTRAP allows for rapid isolation of cell-type-specific localized translation and is applicable to classes of previously inaccessible neuronal and non-neuronal cells in vivoSIGNIFICANCE STATEMENT Instructions for making proteins are found in the genome, housed within the nucleus of each cell. These are then copied as RNA and exported to manufacture new proteins. However, in the brain, memory is thought to be encoded by strengthening individual connections (synapses) between neurons far from the nucleus. Thus, to efficiently make new proteins specifically where they are needed, neurons can transport RNAs to sites near synapses to locally produce proteins. Importantly, several mutations that cause autism disrupt this process. It has been assumed this process occurs in all brain regions, but has never been measured in the cortex. We applied a newly developed method measure to study, for the first time, local translation in cortical neurons.


Subject(s)
Cerebral Cortex/metabolism , Gene Expression Profiling , MicroRNAs/metabolism , Neurites/metabolism , Ribosomes/metabolism , Transcription Factors/metabolism , Transcriptome/physiology , Animals , Male , Mice , Mice, Transgenic
16.
Stem Cells Dev ; 26(22): 1597-1611, 2017 11 15.
Article in English | MEDLINE | ID: mdl-28851266

ABSTRACT

Central nervous system injury often leads to functional impairment due, in part, to the formation of an inhibitory glial scar following injury that contributes to poor regeneration. Astrocytes are the major cellular components of the glial scar, which has led to the belief that they are primarily inhibitory following injury. Recent work has challenged this by demonstrating that some astrocytes are required for spinal cord regeneration and astrocytic roles in recovery depend on their phenotype. In this work, two mixed populations containing primarily either fibrous or protoplasmic astrocytes were derived from mouse embryonic stem cells (mESCs). Motoneuron and V2a interneuron growth on live cultures, freeze-lysed cultures, or decellularized extracellular matrix (ECM) from astrocytes were assessed. Both neuronal populations were found to extend significantly longer neurites on protoplasmic-derived substrates than fibrous-derived substrates. Interestingly, neurons extended longer neurites on protoplasmic-derived ECM than fibrous-derived ECM. ECM proteins were compared with in vivo astrocyte expression profiles, and it was found that the ESC-derived ECMs were enriched for astrocyte-specific proteins. Further characterization revealed that protoplasmic ECM had significantly higher levels of axon growth promoting proteins, while fibrous ECM had significantly higher levels of proteins that inhibit axon growth. Supporting this observation, knockdown of spondin-1 improved neurite growth on fibrous ECM, while laminin α5 and γ1 knockdown decreased neurite growth on protoplasmic ECM. These methods allow for scalable production of specific astrocyte subtype-containing populations with different neuronal growth support capacities, and can be used for further studies of the functional importance of astrocyte heterogeneity.


Subject(s)
Astrocytes/cytology , Embryonic Stem Cells/cytology , Nerve Regeneration/physiology , Neurons/cytology , Animals , Extracellular Matrix/metabolism , Glial Fibrillary Acidic Protein/metabolism , Mice , Neurites/physiology , Neurogenesis/physiology , Neuroglia/cytology , Spinal Cord Injuries/metabolism , Spinal Cord Injuries/therapy
17.
Alcohol Clin Exp Res ; 41(9): 1622-1629, 2017 Sep.
Article in English | MEDLINE | ID: mdl-28743164

ABSTRACT

BACKGROUND: Alcohol use disorders are associated with patterns of impulsive/risky decision making on behavioral economic decision tasks, but little is known about the factors affecting drinking-related decisions. METHODS: The effects of incentives and disincentives to attend and drink at hypothetical alcohol-related party events as a function of lifetime (LT) alcohol and antisocial problems were examined in a sample of 434 young adults who varied widely in LT alcohol and antisocial problems. RESULTS: Moderate and high disincentives substantially discouraged decisions to attend the party events and were associated with decisions to drink less at the party events. High versus low party incentives were associated with more attendance decisions. LT antisocial problems were associated with being less deterred from attending by moderate and high disincentives. LT alcohol problems were associated with greater attendance at high party incentive contexts. LT alcohol problems were associated with drinking more at the majority of events; however, the results indicate that young adults with high levels of alcohol problems moderate their drinking in response to moderate and high disincentives. Finally, attendance and drinking decisions on this hypothetical task were significantly related to actual drinking practices. CONCLUSIONS: The results suggest that antisocial symptoms are associated with a reduced sensitivity to the potential negative consequences of drinking, while alcohol problems are associated with a greater sensitivity to the rewarding aspects of partying. The results also underline the value of directly assessing drinking-related decisions in different hypothetical contexts as well as assessing decisions about attendance at risky drinking events in addition to drinking amount decisions.


Subject(s)
Alcohol Drinking/psychology , Alcoholism/psychology , Antisocial Personality Disorder/psychology , Decision Making , Social Environment , Adolescent , Adult , Female , Humans , Male , Motivation , Reward , Risk-Taking , Students , Universities , Young Adult
18.
Proc Natl Acad Sci U S A ; 114(19): E3830-E3838, 2017 05 09.
Article in English | MEDLINE | ID: mdl-28439016

ABSTRACT

Local translation in neuronal processes is key to the alteration of synaptic strength necessary for long-term potentiation, learning, and memory. Here, we present evidence that regulated de novo protein synthesis occurs within distal, perisynaptic astrocyte processes. Astrocyte ribosomal proteins are found adjacent to synapses in vivo, and immunofluorescent detection of peptide elongation in acute slices demonstrates robust translation in distal processes. We have also developed a biochemical approach to define candidate transcripts that are locally translated in astrocyte processes. Computational analyses indicate that astrocyte-localized translation is both sequence-dependent and enriched for particular biological functions, such as fatty acid synthesis, and for pathways consistent with known roles for astrocyte processes, such as GABA and glutamate metabolism. These transcripts also include glial regulators of synaptic refinement, such as Sparc Finally, the transcripts contain a disproportionate amount of a binding motif for the quaking RNA binding protein, a sequence we show can significantly regulate mRNA localization and translation in the astrocytes. Overall, our observations raise the possibility that local production of astrocyte proteins may support microscale alterations of adjacent synapses.


Subject(s)
Astrocytes/metabolism , Cell Nucleus/metabolism , Memory/physiology , Protein Biosynthesis/physiology , RNA, Messenger/metabolism , Synapses/metabolism , Animals , Astrocytes/cytology , Humans , Neurons/classification , Neurons/metabolism
19.
Front Mol Neurosci ; 10: 9, 2017.
Article in English | MEDLINE | ID: mdl-28190998

ABSTRACT

Studies on regulation of gene expression have contributed substantially to understanding mechanisms for the long-term activity-dependent alterations in neural connectivity that are thought to mediate learning and memory. Most of these studies, however, have focused on the regulation of mRNA transcription. Here, we utilized high-throughput sequencing coupled with ribosome footprinting to globally characterize the regulation of translation in primary mixed neuronal-glial cultures in response to sustained depolarization. We identified substantial and complex regulation of translation, with many transcripts demonstrating changes in ribosomal occupancy independent of transcriptional changes. We also examined sequence-based mechanisms that might regulate changes in translation in response to depolarization. We found that these are partially mediated by features in the mRNA sequence-notably upstream open reading frames and secondary structure in the 5' untranslated region-both of which predict downregulation in response to depolarization. Translationally regulated transcripts are also more likely to be targets of FMRP and include genes implicated in autism in humans. Our findings support the idea that control of mRNA translation plays an important role in response to neural activity across the genome.

20.
Brain Imaging Behav ; 11(1): 76-85, 2017 02.
Article in English | MEDLINE | ID: mdl-26809287

ABSTRACT

Externalizing psychopathology (EXT) is characterized by regulatory deficits of behavior, cognition, and negative emotion. Previous research on EXT suggests that cognitive and affective dysregulation are highly related, such that strong affective states constrain a reduced-capacity cognitive system. Reappraisal is an effective emotional control strategy involving complex interactions between cognitive and affective brain functions and may therefore offer novel insight into the specific neural mechanisms of affective dysregulation among individuals with EXT. To evaluate these possibilities, we tested individuals with low or high EXT in a reappraisal paradigm. Neuroimaging results indicated that EXT was associated with hypo-activation in the amygdala and superior parietal lobule during both maintenance and reappraisal as well as poor modulation of the lateral occipital cortex during negative emotion reappraisal. These results suggest a general disruption of perceptual-attentional resource allocation such that high EXT individuals are characterized by poor modulation of perceptual-attentional resources during reappraisal. Subsequently, emotion reappraisal may be a useful but not adequate tool to control negative affect in EXT.


Subject(s)
Brain/physiopathology , Emotional Intelligence/physiology , Emotions/physiology , Executive Function/physiology , Mental Disorders/physiopathology , Brain/diagnostic imaging , Brain Mapping , Female , Humans , Magnetic Resonance Imaging , Male , Mental Disorders/diagnostic imaging , Neuropsychological Tests , Psychiatric Status Rating Scales , Young Adult
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