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1.
Circ Res ; 126(2): 182-196, 2020 01 17.
Article in English | MEDLINE | ID: mdl-31709908

ABSTRACT

RATIONALE: Hypertrophied hearts switch from mainly using fatty acids (FAs) to an increased reliance on glucose for energy production. It has been shown that preserving FA oxidation (FAO) prevents the pathological shift of substrate preference, preserves cardiac function and energetics, and reduces cardiomyocyte hypertrophy during cardiac stresses. However, it remains elusive whether substrate metabolism regulates cardiomyocyte hypertrophy directly or via a secondary effect of improving cardiac energetics. OBJECTIVE: The goal of this study was to determine the mechanisms of how preservation of FAO prevents the hypertrophic growth of cardiomyocytes. METHODS AND RESULTS: We cultured adult rat cardiomyocytes in a medium containing glucose and mixed-chain FAs and induced pathological hypertrophy by phenylephrine. Phenylephrine-induced hypertrophy was associated with increased glucose consumption and higher intracellular aspartate levels, resulting in increased synthesis of nucleotides, RNA, and proteins. These changes could be prevented by increasing FAO via deletion of ACC2 (acetyl-CoA-carboxylase 2) in phenylephrine-stimulated cardiomyocytes and in pressure overload-induced cardiac hypertrophy in vivo. Furthermore, aspartate supplementation was sufficient to reverse the antihypertrophic effect of ACC2 deletion demonstrating a causal role of elevated aspartate level in cardiomyocyte hypertrophy. 15N and 13C stable isotope tracing revealed that glucose but not glutamine contributed to increased biosynthesis of aspartate, which supplied nitrogen for nucleotide synthesis during cardiomyocyte hypertrophy. CONCLUSIONS: Our data show that increased glucose consumption is required to support aspartate synthesis that drives the increase of biomass during cardiac hypertrophy. Preservation of FAO prevents the shift of metabolic flux into the anabolic pathway and maintains catabolic metabolism for energy production, thus preventing cardiac hypertrophy and improving myocardial energetics.


Subject(s)
Aspartic Acid/biosynthesis , Cardiomegaly/metabolism , Glucose/metabolism , Myocytes, Cardiac/metabolism , Acetyl-CoA Carboxylase/metabolism , Animals , Aspartic Acid/pharmacology , Cardiomegaly/etiology , Cells, Cultured , Fatty Acids/metabolism , Male , Mice , Myocytes, Cardiac/drug effects , Rats , Rats, Wistar
2.
Circulation ; 142(10): 983-997, 2020 09 08.
Article in English | MEDLINE | ID: mdl-32597196

ABSTRACT

BACKGROUND: Increased fatty acid oxidation (FAO) has long been considered a culprit in the development of obesity/diabetes mellitus-induced cardiomyopathy. However, enhancing cardiac FAO by removing the inhibitory mechanism of long-chain fatty acid transport into mitochondria via deletion of acetyl coenzyme A carboxylase 2 (ACC2) does not cause cardiomyopathy in nonobese mice, suggesting that high FAO is distinct from cardiac lipotoxicity. We hypothesize that cardiac pathology-associated obesity is attributable to the imbalance of fatty acid supply and oxidation. Thus, we here seek to determine whether further increasing FAO by inducing ACC2 deletion prevents obesity-induced cardiomyopathy, and if so, to elucidate the underlying mechanisms. METHODS: We induced high FAO in adult mouse hearts by cardiac-specific deletion of ACC2 using a tamoxifen-inducible model (ACC2 iKO). Control and ACC2 iKO mice were subjected to high-fat diet (HFD) feeding for 24 weeks to induce obesity. Cardiac function, mitochondria function, and mitophagy activity were examined. RESULTS: Despite both control and ACC2 iKO mice exhibiting a similar obese phenotype, increasing FAO oxidation by deletion of ACC2 prevented HFD-induced cardiac dysfunction, pathological remodeling, and mitochondria dysfunction, as well. Similarly, increasing FAO by knockdown of ACC2 prevented palmitate-induced mitochondria dysfunction and cardiomyocyte death in vitro. Furthermore, HFD suppressed mitophagy activity and caused damaged mitochondria to accumulate in the heart, which was attenuated, in part, in the ACC2 iKO heart. Mechanistically, ACC2 iKO prevented HFD-induced downregulation of parkin. During stimulation for mitophagy, mitochondria-localized parkin was severely reduced in control HFD-fed mouse heart, which was restored, in part, in ACC2 iKO HFD-fed mice. CONCLUSIONS: These data show that increasing cardiac FAO alone does not cause cardiac dysfunction, but protects against cardiomyopathy in chronically obese mice. The beneficial effect of enhancing cardiac FAO in HFD-induced obesity is mediated, in part, by the maintenance of mitochondria function through regulating parkin-mediated mitophagy. Our findings also suggest that targeting the parkin-dependent mitophagy pathway could be an effective strategy against the development of obesity-induced cardiomyopathy.


Subject(s)
Cardiomyopathies/prevention & control , Diet, High-Fat/adverse effects , Fatty Acids/metabolism , Mitochondria, Heart/metabolism , Mitophagy/drug effects , Ubiquitin-Protein Ligases/metabolism , Acetyl-CoA Carboxylase/genetics , Acetyl-CoA Carboxylase/metabolism , Animals , Cardiomyopathies/chemically induced , Cardiomyopathies/genetics , Cardiomyopathies/metabolism , Mice , Mice, Knockout , Mitochondria, Heart/genetics , Mitophagy/genetics , Oxidation-Reduction/drug effects , Ubiquitin-Protein Ligases/genetics
3.
J Neurosci ; 34(34): 11366-84, 2014 Aug 20.
Article in English | MEDLINE | ID: mdl-25143617

ABSTRACT

The habenular complex in the epithalamus consists of distinct regions with diverse neuronal populations. Past studies have suggested a role for the habenula in voluntary exercise motivation and reinforcement of intracranial self-stimulation but have not assigned these effects to specific habenula subnuclei. Here, we have developed a genetic model in which neurons of the dorsal medial habenula (dMHb) are developmentally eliminated, via tissue-specific deletion of the transcription factor Pou4f1 (Brn3a). Mice with dMHb lesions perform poorly in motivation-based locomotor behaviors, such as voluntary wheel running and the accelerating rotarod, but show only minor abnormalities in gait and balance and exhibit normal levels of basal locomotion. These mice also show deficits in sucrose preference, but not in the forced swim test, two measures of depression-related phenotypes in rodents. We have also used Cre recombinase-mediated expression of channelrhodopsin-2 and halorhodopsin to activate dMHb neurons or silence their output in freely moving mice, respectively. Optical activation of the dMHb in vivo supports intracranial self-stimulation, showing that dMHb activity is intrinsically reinforcing, whereas optical silencing of dMHb outputs is aversive. Together, our findings demonstrate that the dMHb is involved in exercise motivation and the regulation of hedonic state, and is part of an intrinsic reinforcement circuit.


Subject(s)
Habenula/physiology , Motivation/physiology , Motor Activity/physiology , Reinforcement, Psychology , Animals , Channelrhodopsins , Conditioning, Operant , Food Preferences , Habenula/cytology , Locomotion/genetics , Locomotion/physiology , Mice , Mice, Inbred C57BL , Mice, Transgenic , Motivation/genetics , Motor Activity/genetics , Neurons/physiology , Optogenetics , Self Stimulation , Swimming/physiology , Synaptotagmins/genetics , Transcription Factor Brn-3A/deficiency , Transcription Factor Brn-3A/genetics , beta-Galactosidase/genetics , beta-Galactosidase/metabolism
4.
J Neurosci ; 33(46): 18022-35, 2013 Nov 13.
Article in English | MEDLINE | ID: mdl-24227714

ABSTRACT

The Chrna5 gene encodes the α5 nicotinic acetylcholine receptor subunit, an "accessory" subunit of pentameric nicotinic receptors, that has been shown to play a role in nicotine-related behaviors in rodents and is genetically linked to smoking behavior in humans. Here we have used a BAC transgenic mouse line, α5(GFP), to examine the cellular phenotype, connectivity, and function of α5-expressing neurons. Although the medial habenula (MHb) has been proposed as a site of α5 function, α5(GFP) is not detectable in the MHb, and α5 mRNA is expressed there only at very low levels. However, α5(GFP) is strongly expressed in a subset of neurons in the interpeduncular nucleus (IP), median raphe/paramedian raphe (MnR/PMnR), and dorsal tegmental area (DTg). Double-label fluorescence in situ hybridization reveals that these neurons are exclusively GABAergic. Transgenic and conventional tract tracing show that α5(GFP) neurons in the IP project principally to the MnR/PMnR and DTg/interfascicular dorsal raphe, both areas rich in serotonergic neurons. The α5(GFP) neurons in the IP are located in a region that receives cholinergic fiber inputs from the ventral MHb, and optogenetically assisted circuit mapping demonstrates a monosynaptic connection between these cholinergic neurons and α5(GFP) IP neurons. Selective inhibitors of both α4ß2- and α3ß4-containing nicotinic receptors were able to reduce nicotine-evoked inward currents in α5(GFP) neurons in the IP, suggesting a mixed nicotinic receptor profile in these cells. Together, these findings show that the α5-GABAergic interneurons form a link from the MHb to serotonergic brain centers, which is likely to mediate some of the behavioral effects of nicotine.


Subject(s)
GABAergic Neurons/metabolism , Gene Expression Regulation , Habenula/physiology , Nerve Net/physiology , Receptors, GABA-A/biosynthesis , Animals , Female , Male , Mice , Mice, Inbred C57BL , Mice, Transgenic , Organ Culture Techniques , Serotonergic Neurons/metabolism
5.
Dev Biol ; 365(1): 152-63, 2012 May 01.
Article in English | MEDLINE | ID: mdl-22586713

ABSTRACT

Hmx1 is a variant homeodomain transcription factor expressed in the developing sensory nervous system, retina, and craniofacial mesenchyme. Recently, mutations at the Hmx1 locus have been linked to craniofacial defects in humans, rats, and mice, but its role in nervous system development is largely unknown. Here we show that Hmx1 is expressed in a subset of sensory neurons in the cranial and dorsal root ganglia which does not correspond to any specific sensory modality. Sensory neurons in the dorsal root and trigeminal ganglia of Hmx1dm/dm mouse embryos have no detectable Hmx1 protein, yet they undergo neurogenesis and express sensory subtype markers normally, demonstrating that Hmx1 is not globally required for the specification of sensory neurons from neural crest precursors. Loss of Hmx1 expression has no obvious effect on the early development of the trigeminal (V), superior (IX/X), or dorsal root ganglia neurons in which it is expressed, but results in marked defects in the geniculate (VII) ganglion. Hmx1dm/dm mouse embryos possess only a vestigial posterior auricular nerve, and general somatosensory neurons in the geniculate ganglion are greatly reduced by mid-gestation. Although Hmx1 is expressed in geniculate neurons prior to cell cycle exit, it does not appear to be required for neurogenesis, and the loss of geniculate neurons is likely to be the result of increased cell death. Fate mapping of neural crest-derived tissues indicates that Hmx1-expressing somatosensory neurons at different axial levels may be derived from either the neural crest or the neurogenic placodes.


Subject(s)
Geniculate Ganglion/physiology , Homeodomain Proteins/physiology , Transcription Factors/physiology , Animals , Cell Differentiation/physiology , Geniculate Ganglion/embryology , Mice , Nerve Tissue Proteins/physiology , Neural Crest/cytology , Neural Crest/embryology , Neurogenesis/physiology , Organ Specificity , Sensory Receptor Cells/cytology , Sensory Receptor Cells/physiology
6.
J Clin Microbiol ; 47(11): 3653-62, 2009 Nov.
Article in English | MEDLINE | ID: mdl-19776232

ABSTRACT

In recent years, enterovirus 71 (EV71) has been a cause of numerous outbreaks of hand-foot-and-mouth disease, with severe neurological complications in the Asia-Pacific region. The reemergence in Taiwan of EV71 genotype B5 in 2008 resulted in the largest outbreak of EV71 in Taiwan in the past 11 years. Phylogenetic analyses indicated that dominant genotype changes from B to C or C to B occurred at least three times between 1986 and 2008. Furthermore, antigenic cartography of EV71 by using neutralization tests revealed that the reemerging EV71 genotype B5 strains formed a separate cluster which was antigenically distinct from the B4 and C genotypes. Moreover, analyses of full-length genomic sequences of EV71 circulating in Taiwan during this period showed the occurrence of intra- and interserotypic recombination. Therefore, continuous surveillance of EV71 including the monitoring of genetic evolution and antigenic changes is recommended and may contribute to the development of a vaccine for EV71.


Subject(s)
Antigens, Viral/genetics , Disease Outbreaks , Enterovirus A, Human/isolation & purification , Enterovirus Infections/epidemiology , Enterovirus Infections/virology , Evolution, Molecular , RNA, Viral/genetics , Antibodies, Neutralizing/immunology , Antibodies, Viral/immunology , Cluster Analysis , Enterovirus A, Human/classification , Enterovirus A, Human/genetics , Enterovirus A, Human/immunology , Humans , Molecular Sequence Data , Phylogeny , Sequence Analysis, DNA , Sequence Homology , Serotyping , Taiwan/epidemiology
7.
Commun Biol ; 2: 326, 2019.
Article in English | MEDLINE | ID: mdl-31508501

ABSTRACT

The kidney's inherent complexity has made identifying cell-specific pathways challenging, particularly when temporally associating them with the dynamic pathophysiology of acute kidney injury (AKI). Here, we combine renal cell-specific luciferase reporter mice using a chemoselective luciferin to guide the acquisition of cell-specific transcriptional changes in C57BL/6 background mice. Hydrogen peroxide generation, a common mechanism of tissue damage, was tracked using a peroxy-caged-luciferin to identify optimum time points for immunoprecipitation of labeled ribosomes for RNA-sequencing. Together, these tools revealed a profound impact of AKI on mitochondrial pathways in the collecting duct. In fact, targeting the mitochondria with an antioxidant, ameliorated not only hydrogen peroxide generation, but also significantly reduced oxidative stress and the expression of the AKI biomarker, LCN2. This integrative approach of coupling physiological imaging with transcriptomics and drug testing revealed how the collecting duct responds to AKI and opens new venues for cell-specific predictive monitoring and treatment.


Subject(s)
Acute Kidney Injury/genetics , Imaging, Three-Dimensional , Ischemia/genetics , Ischemia/pathology , Transcriptome/genetics , Acute Kidney Injury/complications , Acute Kidney Injury/pathology , Animals , Antioxidants/metabolism , Kidney Tubules, Collecting/injuries , Kidney Tubules, Collecting/pathology , Mice, Inbred C57BL , Nephrons/metabolism , Nephrons/pathology , Oxidative Stress , Reactive Oxygen Species/metabolism , Reperfusion Injury/complications , Reperfusion Injury/genetics , Reperfusion Injury/pathology
8.
Virus Res ; 131(2): 250-9, 2008 Feb.
Article in English | MEDLINE | ID: mdl-18036697

ABSTRACT

Genetic recombination is a well-known phenomenon for enteroviruses. In this study, we determined the phylogenetic relationships of five distinct regions of the EV71 genome for 73 EV71 isolates from 1986 and from 1998 to 2005 in Taiwan. Phylogenetic analyses showed that the 5'-UTR, VP4-VP2, VP1, and 3D regions of EV71 isolated in 2004 and 2005 were grouped into genotype C. However, the 2B region of these isolates differed in that it grouped with genotype B, indicating recombination within EV71 had occurred. This intratypic recombination was first seen in 2002 and became predominant in 2004 and 2005. The simplot and bootscan analyses identified two recombination points located at the 3'-termini of the 2A and 3C regions. This intratypic recombination was identified among naturally circulating EV71 isolates in Taiwan, therefore, it suggests that nonstructural genes may recombine to produce new EV71 variants.


Subject(s)
Enterovirus A, Human/genetics , Enterovirus Infections/virology , Recombination, Genetic , 5' Untranslated Regions/genetics , Cluster Analysis , Enterovirus A, Human/isolation & purification , Evolution, Molecular , Genome, Viral , Genotype , Humans , Molecular Sequence Data , Phylogeny , RNA, Viral/genetics , Sequence Analysis, DNA , Sequence Homology , Taiwan , Viral Proteins/genetics
9.
J Biol Rhythms ; 32(5): 444-455, 2017 Oct.
Article in English | MEDLINE | ID: mdl-28954569

ABSTRACT

In nocturnal rodents, voluntary wheel-running activity (WRA) represents a self-reinforcing behavior. We have previously demonstrated that WRA is markedly reduced in mice with a region-specific deletion of the transcription factor Pou4f1 (Brn3a), which leads to an ablation of the dorsal medial habenula (dMHb). The decrease in WRA in these dMHb-lesioned (dMHbCKO) mice suggests that the dMHb constitutes a critical center for conveying reinforcement by exercise. However, WRA also represents a prominent output of the circadian system, and the possibility remains that the dMHb is a source of input to the master circadian pacemaker located in the suprachiasmatic nucleus (SCN) of the hypothalamus. To test this hypothesis, we assessed the integrity of the circadian system in dMHbCKO mice. Here we show that the developmental lesion of the dMHb reduces WRA under both a light-dark cycle and constant darkness, increases the circadian period of WRA, but has no effect on the circadian amplitude or period of home cage activity or the daily amplitude of sleep stages, suggesting that the lengthening of period is a result of the decreased WRA in the mutant mice. Polysomnographic sleep recordings show that dMHbCKO mice have an overall unaltered daily amplitude of sleep stages but have fragmented sleep and an overall increase in total rapid eye movement (REM) sleep. Photoresponsiveness is intact in dMHbCKO mice, but compared with control animals, they reentrain faster to a 6-h abrupt phase delay protocol. Circadian changes in WRA of dMHbCKO mice do not appear to emerge within the central pacemaker, as circadian expression of the clock genes Per1 and Per2 within the SCN is normal. We do find some evidence for fragmented sleep and an overall increase in total REM sleep, supporting a model in which the dMHb is part of the neural circuitry encoding motivation and involved in the manifestation of some of the symptoms of depression.


Subject(s)
Circadian Rhythm , Habenula/physiology , Motor Activity , Animals , Circadian Rhythm/genetics , Circadian Rhythm/physiology , Darkness , Depression , Habenula/pathology , Light , Locomotion/genetics , Mice , Period Circadian Proteins/genetics , Period Circadian Proteins/metabolism , Photoperiod , Sleep , Sleep, REM , Suprachiasmatic Nucleus/physiology , Transcription Factor Brn-3A/genetics , Transcription Factor Brn-3A/metabolism
10.
J Comp Neurol ; 496(3): 406-21, 2006 May 20.
Article in English | MEDLINE | ID: mdl-16566002

ABSTRACT

In this study, the peptide VYRKPPFNGSIFamide (Val(1)-SIFamide) was identified in the stomatogastric nervous system (STNS) of the American lobster, Homarus americanus, using matrix-assisted laser desorption/ionization-Fourier transform mass spectrometry (MALDI-FTMS). When bath-applied to the stomatogastric ganglion (STG), synthetic Val(1)-SIFamide activated the pyloric motor pattern, increasing both burst amplitude and duration in the pyloric dilator (PD) neurons. To determine the distribution of this novel SIFamide isoform within the lobster STNS and neuroendocrine organs, a rabbit polyclonal antibody was generated against synthetic Val(1)-SIFamide. Whole-mount immunolabeling with this antibody showed that this peptide is widely distributed within the STNS, including extensive neuropil staining in the STG and commissural ganglia (CoGs) as well as immunopositive somata in the CoGs and the oesophageal ganglion. Labeling was also occasionally seen in the pericardial organ (PO), but not in the sinus gland. When present in the PO, labeling was restricted to fibers-of-passage and was never seen in release terminals. Adsorption of the antibody by either Val(1)-SIFamide or Gly(1)-SIFamide abolished all Val(1)-SIFamide staining within the STNS, including the STG neuropil, whereas adsorption by other lobster neuropeptides had no effect on immunolabeling. These data strongly suggest that the staining we report is a true reflection of the distribution of this peptide in the STNS. Collectively, our mass spectrometric, physiological, and anatomical data are consistent with Val(1)-SIFamide serving as a locally released neuromodulator in the lobster STG. Thus, our study provides the first direct demonstration of function for an SIFamide isoform in any species.


Subject(s)
Digestive System/innervation , Nephropidae/metabolism , Nervous System Physiological Phenomena , Nervous System/metabolism , Neurons/physiology , Neuropeptides/metabolism , Animals , Digestive System/drug effects , Ganglia, Invertebrate/metabolism , Immunohistochemistry/methods , In Vitro Techniques , Models, Neurological , Nephropidae/anatomy & histology , Nervous System Physiological Phenomena/drug effects , Neurons/drug effects , Neuropeptides/isolation & purification , Neuropeptides/pharmacology , Neurosecretory Systems/metabolism , Pyloric Antrum/drug effects , Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization/methods , Time Factors
11.
eNeuro ; 3(3)2016.
Article in English | MEDLINE | ID: mdl-27482535

ABSTRACT

Animal models have been developed to investigate aspects of stress, anxiety, and depression, but our understanding of the circuitry underlying these models remains incomplete. Prior studies of the habenula, a poorly understood nucleus in the dorsal diencephalon, suggest that projections to the medial habenula (MHb) regulate fear and anxiety responses, whereas the lateral habenula (LHb) is involved in the expression of learned helplessness, a model of depression. Tissue-specific deletion of the transcription factor Pou4f1 in the dorsal MHb (dMHb) results in a developmental lesion of this subnucleus. These dMHb-ablated mice show deficits in voluntary exercise, a possible correlate of depression. Here we explore the role of the dMHb in mood-related behaviors and intrinsic reinforcement. Lesions of the dMHb do not elicit changes in contextual conditioned fear. However, dMHb-lesioned mice exhibit shorter immobility time in the tail suspension test, another model of depression. dMHb-lesioned mice also display increased vulnerability to the induction of learned helplessness. However, this effect is not due specifically to the dMHb lesion, but appears to result from Pou4f1 haploinsufficiency elsewhere in the nervous system. Pou4f1 haploinsufficiency does not produce the other phenotypes associated with dMHb lesions. Using optogenetic intracranial self-stimulation, intrinsic reinforcement by the dMHb can be mapped to a specific population of neurokinin-expressing habenula neurons. Together, our data show that the dMHb is involved in the regulation of multiple mood-related behaviors, but also support the idea that these behaviors do not reflect a single functional pathway.


Subject(s)
Affect/physiology , Habenula/metabolism , Neurons/metabolism , Reinforcement, Psychology , Tachykinins/metabolism , Transcription Factor Brn-3A/deficiency , Animals , Avoidance Learning/physiology , Conditioning, Psychological/physiology , Depression/metabolism , Fear/physiology , Gene Expression , Helplessness, Learned , Male , Mice, Inbred C57BL , Mice, Transgenic , Motor Activity/physiology , Septum of Brain/metabolism , Spatial Behavior/physiology , Tissue Culture Techniques , Transcription Factor Brn-3A/genetics
12.
J Comp Neurol ; 493(4): 607-26, 2005 Dec 26.
Article in English | MEDLINE | ID: mdl-16304631

ABSTRACT

In crustaceans, circulating hormones influence many physiological processes. Two neuroendocrine organs, the sinus gland (SG) and the pericardial organ (PO), are the sources of many of these compounds. As a first step in determining the roles played by hemolymph-borne agents in the crab Cancer productus, we characterized the hormone complement of its SG and PO. We show via transmission electron microscopy that the nerve terminals making up each site possess dense-core and/or electron-lucent vesicles, suggesting diverse complements of bioactive molecules for both structures. By using immunohistochemistry, we show that small molecule transmitters, amines and peptides, are among the hormones present in these tissues, with many differentially distributed between the two sites (e.g., serotonin in the PO but not the SG). With several mass spectrometric (MS) methods, we identified many of the peptides responsible for the immunolabeling and surveyed the SG and PO for peptides for which no antibodies exist. By using MS, we characterized 39 known peptides [e.g., beta-pigment-dispersing hormone (beta-PDH), crustacean cardioactive peptide, and red pigment-concentrating hormone] and de novo sequenced 23 novel ones (e.g., a new beta-PDH isoform and the first B-type allatostatins identified from a non-insect species). Collectively, our results show that diverse and unique complements of hormones, including many previously unknown peptides, are present in the SG and PO of C. productus. Moreover, our study sets the stage for future biochemical and physiological studies of these molecules and ultimately the elucidation of the role(s) they play in hormonal control in C. productus.


Subject(s)
Brachyura/metabolism , Endocrine Glands/metabolism , Endocrine Glands/ultrastructure , Invertebrate Hormones/metabolism , Neurons/ultrastructure , Neurosecretory Systems/ultrastructure , Animals , Brachyura/ultrastructure , Immunohistochemistry , Invertebrate Hormones/classification , Neurons/metabolism , Neurosecretory Systems/metabolism , Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
13.
Mol Brain ; 6: 60, 2013 Dec 27.
Article in English | MEDLINE | ID: mdl-24373546

ABSTRACT

BACKGROUND: Neuropeptides are a diverse category of signaling molecules in the nervous system regulating a variety of processes including food intake, social behavior, circadian rhythms, learning, and memory. Both the identification and functional characterization of specific neuropeptides are ongoing fields of research. Matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF MS) analysis of nervous tissues from a variety of organisms allows direct detection and identification of neuropeptides. Here, we demonstrate an analysis workflow that allows for the detection of differences in specific neuropeptides amongst a variety of neuropeptides being simultaneously measured. For sample preparation, we describe a straight-forward and rapid (minutes) method where individual adult Drosophila melanogaster brains are analyzed. Using a MATLAB-based data analysis workflow, also compatible with MALDI-TOF mass spectra obtained from other sample preparations and instrumentation, we demonstrate how changes in neuropeptides levels can be detected with this method. RESULTS: Over fifty isotopically resolved ion signals in the peptide mass range are reproducibly observed across experiments. MALDI-TOF MS profile spectra were used to statistically identify distinct relative differences in organ-wide endogenous levels of detected neuropeptides between biological conditions. In particular, three distinct levels of a particular neuropeptide, pigment dispersing factor, were detected by comparing groups of preprocessed spectra obtained from individual brains across three different D. melanogaster strains, each of which express different amounts of this neuropeptide. Using the same sample preparation, MALDI-TOF/TOF tandem mass spectrometry confirmed that at least 14 ion signals observed across experiments are indeed neuropeptides. Among the identified neuropeptides were three products of the neuropeptide-like precursor 1 gene previously not identified in the literature. CONCLUSIONS: Using MALDI-TOF MS and preprocessing/statistical analysis, changes in relative levels of a particular neuropeptide in D. melanogaster tissue can be statistically detected amongst a variety of neuropeptides. While the data analysis methods should be compatible with other sample preparations, the presented sample preparation method was sufficient to identify previously unconfirmed D. melanogaster neuropeptides.


Subject(s)
Drosophila melanogaster/metabolism , Neuropeptides/metabolism , Proteomics/methods , Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization/methods , Amino Acid Sequence , Animals , Confidence Intervals , Drosophila Proteins/chemistry , Drosophila Proteins/metabolism , Ions , Isotope Labeling , Molecular Sequence Data , Neuropeptides/chemistry , Neuropeptides/isolation & purification , Signal Processing, Computer-Assisted
14.
Nat Neurosci ; 15(5): 793-802, 2012 Mar 25.
Article in English | MEDLINE | ID: mdl-22446880

ABSTRACT

Cell type-specific expression of optogenetic molecules allows temporally precise manipulation of targeted neuronal activity. Here we present a toolbox of four knock-in mouse lines engineered for strong, Cre-dependent expression of channelrhodopsins ChR2-tdTomato and ChR2-EYFP, halorhodopsin eNpHR3.0 and archaerhodopsin Arch-ER2. All four transgenes mediated Cre-dependent, robust activation or silencing of cortical pyramidal neurons in vitro and in vivo upon light stimulation, with ChR2-EYFP and Arch-ER2 demonstrating light sensitivity approaching that of in utero or virally transduced neurons. We further show specific photoactivation of parvalbumin-positive interneurons in behaving ChR2-EYFP reporter mice. The robust, consistent and inducible nature of our ChR2 mice represents a significant advance over previous lines, and the Arch-ER2 and eNpHR3.0 mice are to our knowledge the first demonstration of successful conditional transgenic optogenetic silencing. When combined with the hundreds of available Cre driver lines, this optimized toolbox of reporter mice will enable widespread investigations of neural circuit function with unprecedented reliability and accuracy.


Subject(s)
Brain/cytology , Integrases/metabolism , Light , Neurogenesis/physiology , Neurons/physiology , Action Potentials/physiology , Animals , Archaeal Proteins , Channelrhodopsins , Electroporation/methods , Halorhodopsins/genetics , Halorhodopsins/metabolism , In Vitro Techniques , Integrases/genetics , Luminescent Proteins/genetics , Mice , Mice, Transgenic , Neurogenesis/genetics , Optics and Photonics , Proteins/genetics , RNA, Untranslated , Wakefulness
15.
J Biol Rhythms ; 26(6): 518-29, 2011 Dec.
Article in English | MEDLINE | ID: mdl-22215610

ABSTRACT

Intertidal species have both circadian and circatidal clocks. Although the behavioral evidence for these oscillators is more than 5 decades old, virtually nothing is known about their molecular clockwork. Pigment-dispersing hormones (PDHs) were originally described in crustaceans. Their insect homologs, pigment-dispersing factors (PDFs), have a prominent role as clock output and synchronizing signals released from clock neurons. We show that gene duplication in crabs has led to two PDH genes (ß-pdh-I and ß-pdh-II). Phylogenetically, ß-pdh-I is more closely related to insect pdf than to ß-pdh-II, and we hypothesized that ß-PDH-I may represent a canonical clock output signal. Accordingly, ß-PDH-I expression in the brain of the intertidal crab Cancer productus is similar to that of PDF in Drosophila melanogaster, and neurons that express PDH-I also show CYCLE-like immunoreactivity. Using D. melanogaster pdf-null mutants (pdf(01)) as a heterologous system, we show that ß-pdh-I is indistinguishable from pdf in its ability to rescue the mutant arrhythmic phenotype, but ß-pdh-II fails to restore the wild-type phenotype. Application of the three peptides to explanted brains shows that PDF and ß-PDH-I are equally effective in inducing the signal transduction cascade of the PDF receptor, but ß-PDH-II fails to induce a normal cascade. Our results represent the first functional characterization of a putative molecular clock output in an intertidal species and may provide a critical step towards the characterization of molecular components of biological clocks in intertidal organisms.


Subject(s)
Biological Clocks/physiology , Brachyura/physiology , Drosophila Proteins/metabolism , Drosophila melanogaster/physiology , Neuropeptides/metabolism , Peptides/metabolism , Signal Transduction/physiology , Amino Acid Sequence , Animals , Behavior, Animal/physiology , Brachyura/anatomy & histology , Brain/anatomy & histology , Brain/metabolism , Circadian Rhythm/physiology , Drosophila Proteins/classification , Drosophila Proteins/genetics , Drosophila melanogaster/anatomy & histology , Gene Duplication , Molecular Sequence Data , Neurons/metabolism , Neuropeptides/classification , Neuropeptides/genetics , Peptides/classification , Peptides/genetics , Phenotype , Phylogeny , Sequence Alignment
16.
Front Biosci (Elite Ed) ; 2(4): 1394-404, 2010 06 01.
Article in English | MEDLINE | ID: mdl-20515812

ABSTRACT

Animals with habitats within the intertidal zone are exposed to environmental cycles that include the ebb and flow of tidal waters, changes in tidal levels associated with the lunar month, the light-dark cycle and the alternation of seasons. This intricate temporal environment results in the selection of biological timing systems with endogenous clocks that can oscillate with this wide range of periodicities. Whereas great progress has been made in our understanding of the molecular and neural bases of circadian rhythms, that is, endogenous rhythms synchronized to the solar day, there is little understanding on how circatidal rhythms, namely endogenous rhythms synchronized to tides, are generated. Intertidal crustaceans have been a pivotal group for the demonstration of the endogenous nature of circatidal rhythms and their mechanisms of entrainment. We review here some of the classic work using intertidal crustaceans to unmask basic properties of circatidal systems, as well as work from our laboratory that aims to identify putative chemical signals that could be involved in the circatidal systems of decapod crustaceans.


Subject(s)
Biological Clocks , Crustacea/physiology , Animals , Water Movements
17.
J Clin Virol ; 45(2): 129-34, 2009 Jun.
Article in English | MEDLINE | ID: mdl-19394265

ABSTRACT

BACKGROUND: In Taiwan, trivalent oral poliovirus vaccine (tOPV) is in the routine immunization schedule, but its association with illnesses had not been examined. OBJECTIVES: To investigate clinical presentations and viral characteristics of patients with poliovirus isolates. STUDY DESIGN: Clinical data, vaccination records and viral sequences were retrospectively analyzed for patients from whom polioviruses were isolated during 2000-2005. RESULTS: OPV-like strains were the only pathogen identified in 208 children who were diagnosed with lower respiratory tract infection (24.5%), acute gastroenteritis (16.8%) or upper respiratory tract infection (10.6%). Timing of poliovirus isolation relative to the tOPV vaccination was unusual in 59 patients, including 6 before any dose and 53 more than 10 weeks after the 3rd or later dose of tOPV. Sequence analyses of the VP1, 2C and 3C/D regions for 19 poliovirus isolates revealed that 4 had previously reported neurovirulence reversions, 1 had intertypic recombination, and 6 had both. No patient had neurological complications, but 3 died of myocarditis, including 2 with recombinant strains and 1 who never received OPV. CONCLUSION: This study describes the isolation of OPV-like strains from patients with a variety of illnesses, raising concerns about their pathogenic potential in an area where tOPV is routinely administered. The detection of genetic variations among OPV-like strains warrants continuing surveillance for these variants in patients with severe illnesses besides neurological complications.


Subject(s)
Poliovirus Vaccine, Oral/adverse effects , Poliovirus/classification , Poliovirus/isolation & purification , Child , Child, Preschool , Female , Gastroenteritis/virology , Humans , Infant , Male , Phylogeny , Pneumonia/virology , Poliovirus/genetics , RNA, Viral/genetics , Respiratory Tract Infections/virology , Sequence Analysis, DNA , Taiwan
18.
Gen Comp Endocrinol ; 155(3): 517-25, 2008 Feb 01.
Article in English | MEDLINE | ID: mdl-17961562

ABSTRACT

Recently, we demonstrated that the four known sinus gland (SG) isoforms of Cancer productus crustacean hyperglycemic hormone precursor-related peptide (Capr-CPRP I-IV) are differentially distributed in conserved patterns among individual crabs. This finding strongly supported the presence of multiple prepro-crustacean hyperglycemic hormone (chh) transcripts in each crab, as well as the translation and processing of the encoded prepro-hormones. Whether these transcripts contained common or distinct isoforms of CHH remained unknown. To address this question, molecular analyses of the C. productus eyestalk prepro-chhs were undertaken. Using a PCR-based cloning strategy, four prepro-chh cDNAs were characterized: one encoding CPRP I, one encoding CPRP III (found to possess Ile(26) rather than Leu(26) as reported previously), and two encoding CPRP II. No cDNA encoding CPRP IV was identified. The deduced CHH present in the prepro-hormones containing CPRP I and III were identical (Capr-CHH I) and differed from that (Capr-CHH II) present in the two prepro-hormones containing Capr-CPRP II at a single residue, a Thr(5) for Ser(5) substitution. As both CHH isoforms possess Glu at position 1, a cyclization of this residue to pyroglutamine is likely as the peptides mature, as has been seen for the CHHs of other brachyuran species. Likewise, homology to other CHHs suggests all C. productus isoforms are C-terminally amidated. These post-translational modifications would result in four SG isoforms of CHH: Capr-CHH I, Capr-pyro-CHH I, Capr-CHH II, and Capr-pyro-CHH II. Southern blotting supported the hypothesis that at least three prepro-chh transcripts are present in each crab, while dual in situ hybridization-immunohistochemistry localized the transcripts to previously mapped CHH immunopositive somata in the X-organ, the major source of innervation to the SG.


Subject(s)
Brachyura/genetics , Endocrine Glands/metabolism , Nerve Tissue Proteins/genetics , Nerve Tissue Proteins/metabolism , Protein Precursors/genetics , Protein Precursors/metabolism , Protein Processing, Post-Translational , Amino Acid Sequence , Animals , Base Sequence , Cloning, Molecular , DNA, Complementary/isolation & purification , Eye/chemistry , Eye/metabolism , Molecular Sequence Data , Peptide Hormones/genetics , Peptide Hormones/metabolism , Protein Isoforms/genetics , Protein Isoforms/metabolism , Sequence Homology, Amino Acid
19.
J Comp Neurol ; 508(2): 197-211, 2008 May 10.
Article in English | MEDLINE | ID: mdl-18311785

ABSTRACT

Two beta-pigment-dispersing hormone (beta-PDH) isoforms have been identified in several decapod crustaceans, including the crab Cancer productus, but whether these peptides serve common or distinct physiological roles remains to be elucidated. Here we show that the distribution of beta-PDH-like immunoreactivity in the nervous system of C. productus is similar to that found in other brachyurans, suggesting roles as both a circulating hormone and a locally released transmitter for members of this peptide family. cDNAs encoding NSELINSILGLPKVMNDAamide (authentic beta-PDH; here termed Canpr-beta-PDH I) or NSELINSLLGLSRLMNEAamide [corrected](Canpr-beta-PDH II) were cloned. Double in situ hybridization revealed that these two beta-PDH isoforms are differentially distributed within the eyestalk. For example, in most neurons between the medulla interna (MI) and the medulla terminalis (MT), both isoforms appear present; however, in some neurons in this region, mRNA for only one or the other isoform was detected. Likewise, only prepro-beta-pdh I mRNA was detected in the somata of the lamina ganglionaris (LG) and in the brain. By direct tissue mass spectrometry, only Canpr-beta-PDH II was detected in the neurosecretory sinus gland (SG), whereas Canpr-beta-PDH I was found in all other parts of the eyestalk. Collectively, these data suggest distinct functions for each of the C. productus beta-PDHs; Canpr-beta-PDH II appears to be a neurohormone in the SG, whereas Canpr-beta-PDH I may function as a local transmitter/modulator. Our data support the hypothesis that duplication and subsequent mutation of a common neuropeptide gene may underlie the evolution of two differentially distributed transcripts that serve distinct physiological roles.


Subject(s)
Brachyura/metabolism , Cloning, Molecular/methods , Gene Expression/physiology , Peptides/genetics , Peptides/metabolism , Animals , Brachyura/ultrastructure , Fourier Analysis , Mass Spectrometry , Microscopy, Confocal , Nervous System/metabolism , Protein Isoforms/genetics , Protein Isoforms/metabolism
20.
Gen Comp Endocrinol ; 154(1-3): 184-92, 2007.
Article in English | MEDLINE | ID: mdl-17698069

ABSTRACT

Over the past decade, mass spectrometry has become a prominent technique for identifying peptide hormones. In crustaceans, studies directed at characterizing the peptide complements present in neuroendocrine structures have generally involved the isolation of tissue from a large number of individuals, which are pooled, extracted, purified, and then analyzed via chromatographic techniques coupled with mass spectrometry. While this approach provides information on the peptides present in the population of animals used as the tissue source, data on the peptide complement present in any individual animal are lost. Direct tissue matrix assisted laser desorption/ionization Fourier transform mass spectrometry (MALDI-FTMS) of single tissues has the potential to identify differences in peptide expression between individuals. Here, we have used direct tissue MALDI-FTMS of individual sinus glands (SGs) to show that the four isoforms of crustacean hyperglycemic hormone precursor-related peptide (CPRP) identified previously from pooled Cancer productus SGs (i.e. Fu, Q., Christie, A.E., Li, L. 2005. Mass spectrometric characterization of crustacean hyperglycemic hormone precursor-related peptides (CPRPs) from the sinus gland of the crab, Cancer productus. Peptides 26, 2137-2150.) are differentially distributed in conserved patterns among individual crabs. Of the crabs examined, approximately 61% of the individuals possessed Capr-CPRP I and II, but not III or IV, approximately 26% Capr-CPRP I, II and III, but not IV, and approximately 13% Capr-CPRP I, II and IV, but not III. Our findings set the stage for future molecular investigations on the origin(s) of this individual-specific variation in CPRP complement, as well as investigations of the function and regulation of the individual isoforms. These data also lend a cautionary note to the assumption that the peptides identified via pooled tissues reveal an accurate picture of the peptides present in any given individual.


Subject(s)
Brachyura/chemistry , Brachyura/metabolism , Nerve Tissue Proteins/analysis , Nerve Tissue Proteins/metabolism , Protein Precursors/analysis , Protein Precursors/metabolism , Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization/methods , Amino Acid Sequence , Animals , Brachyura/anatomy & histology , Female , Fourier Analysis , Male , Molecular Sequence Data , Peptide Fragments/analysis , Peptide Fragments/metabolism , Protein Isoforms/analysis , Protein Isoforms/metabolism , Tissue Distribution
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