ABSTRACT
The dopaminergic neuromodulator system is fundamental to brain functions. Abnormal dopamine (DA) pathway is implicated in psychiatric disorders, including schizophrenia (SZ) and autism spectrum disorder (ASD). Mutations in Cullin 3 (CUL3), a core component of the Cullin-RING ubiquitin E3 ligase complex, have been associated with SZ and ASD. However, little is known about the function and mechanism of CUL3 in the DA system. Here, we show that CUL3 is critical for the function of DA neurons and DA-relevant behaviors in male mice. CUL3-deficient mice exhibited hyperactive locomotion, deficits in working memory and sensorimotor gating, and increased sensitivity to psychostimulants. In addition, enhanced DA signaling and elevated excitability of the VTA DA neurons were observed in CUL3-deficient animals. Behavioral impairments were attenuated by dopamine D2 receptor antagonist haloperidol and chemogenetic inhibition of DA neurons. Furthermore, we identified HCN2, a hyperpolarization-activated and cyclic nucleotide-gated channel, as a potential target of CUL3 in DA neurons. Our study indicates that CUL3 controls DA neuronal activity by maintaining ion channel homeostasis and provides insight into the role of CUL3 in the pathogenesis of psychiatric disorders.SIGNIFICANCE STATEMENT This study provides evidence that Cullin 3 (CUL3), a core component of the Cullin-RING ubiquitin E3 ligase complex that has been associated with autism spectrum disorder and schizophrenia, controls the excitability of dopamine (DA) neurons in mice. Its DA-specific heterozygous deficiency increased spontaneous locomotion, impaired working memory and sensorimotor gating, and elevated response to psychostimulants. We showed that CUL3 deficiency increased the excitability of VTA DA neurons, and inhibiting D2 receptor or DA neuronal activity attenuated behavioral deficits of CUL3-deficient mice. We found HCN2, a hyperpolarization-activated channel, as a target of CUL3 in DA neurons. Our findings reveal CUL3's role in DA neurons and offer insights into the pathogenic mechanisms of autism spectrum disorder and schizophrenia.
Subject(s)
Autism Spectrum Disorder , Autistic Disorder , Schizophrenia , Animals , Male , Mice , Cullin Proteins/genetics , Cullin Proteins/metabolism , Dopamine/metabolism , Dopaminergic Neurons/physiology , Ubiquitins/metabolism , Ubiquitins/pharmacology , Ventral Tegmental AreaABSTRACT
The volumetric density of the metal atomic site is decisive to the operating efficiency of the photosynthetic nanoreactor, yet its rational design and synthesis remain a grand challenge. Herein, we report a shell-regulating approach to enhance the volumetric density of Co atomic sites onto/into multishell ZnxCd1-xS for greatly improving CO2 photoreduction activity. We first establish a quantitative relation between the number of shell layers, specific surface areas, and volumetric density of atomic sites on multishell ZnxCd1-xS and conclude a positive relation between photosynthetic performance and the number of shell layers. The triple-shell ZnxCd1-xS-Co1 achieves the highest CO yield rate of 7629.7 µmol g-1 h-1, superior to those of the double-shell ZnxCd1-xS-Co1 (5882.2 µmol g-1 h-1) and single-shell ZnxCd1-xS-Co1 (4724.2 µmol g-1 h-1). Density functional theory calculations suggest that high-density Co atomic sites can promote the mobility of photogenerated electrons and enhance the adsorption of Co(bpy)32+ to increase CO2 activation (CO2 â CO2* â COOH* â CO* â CO) via the S-Co-bpy interaction, thereby enhancing the efficiency of photocatalytic CO2 reduction.
ABSTRACT
Dopamine (DA) neurons in the ventral tegmental area (VTA) are critical to coping with stress. However, molecular mechanisms regulating their activity and stress-induced depression were not well understood. We found that the receptor tyrosine kinase ErbB4 in VTA was activated in stress-susceptible mice. Deleting ErbB4 in VTA or in DA neurons, or chemical genetic inhibition of ErbB4 kinase activity in VTA suppressed the development of chronic social defeat stress (CSDS)-induced depression-like behaviors. ErbB4 activation required the expression of NRG1 in the laterodorsal tegmentum (LDTg); LDTg-specific deletion of NRG1 inhibited depression-like behaviors. NRG1 and ErbB4 suppressed potassium currents of VTA DA neurons and increased their firing activity. Finally, we showed that acute inhibition of ErbB4 after stress attenuated DA neuron hyperactivity and expression of depression-like behaviors. Together, these observations demonstrate a critical role of NRG1-ErbB4 signaling in regulating depression-like behaviors and identify an unexpected mechanism by which the LDTg-VTA circuit regulates the activity of DA neurons.
Subject(s)
Depression , Ventral Tegmental Area , Mice , Animals , Ventral Tegmental Area/metabolism , Dopaminergic Neurons/metabolism , Signal Transduction , Phosphorylation , Receptor, ErbB-4/genetics , Receptor, ErbB-4/metabolismABSTRACT
Wnt signaling plays a critical role in production and differentiation of neurons and undergoes a progressive reduction during cortical development. However, how Wnt signaling is regulated is not well understood. Here we provide evidence for an indispensable role of neddylation, a ubiquitylation-like protein modification, in inhibiting Wnt/ß-catenin signaling. We show that ß-catenin is neddylated; and inhibiting ß-catenin neddylation increases its nuclear accumulation and Wnt/ß-catenin signaling. To test this hypothesis in vivo, we mutated Nae1, an obligative subunit of the E1 for neddylation in cortical progenitors. The mutation leads to eventual reduction in radial glia progenitors (RGPs). Consequently, the production of intermediate progenitors (IPs) and neurons is reduced, and neuron migration is impaired, resulting in disorganization of the cerebral cortex. These phenotypes are similar to those of ß-catenin gain-of-function mice. Finally, suppressing ß-catenin expression is able to rescue deficits of Nae1 mutant mice. Together, these observations identified a mechanism to regulate Wnt/ß-catenin signaling in cortical development.
Subject(s)
NEDD8 Protein/metabolism , Animals , Cell Differentiation/physiology , Cell Proliferation , Cerebral Cortex/metabolism , Female , Male , Mice , NEDD8 Protein/genetics , Neural Stem Cells/metabolism , Neurogenesis/physiology , Neurons/metabolism , Signal Transduction/physiology , Ubiquitin-Activating Enzymes/genetics , Ubiquitin-Activating Enzymes/metabolism , Wnt Signaling Pathway/physiology , beta Catenin/metabolismABSTRACT
Myosin X (Myo X) transports cargos to the tips of filopodia for cell adhesion, migration, and neuronal axon guidance. Deleted in Colorectal Cancer (DCC) is one of the Myo X cargos that is essential for Netrin-1-regulated axon pathfinding. The function of Myo X in axon development in vivo and the underlying mechanisms remain elusive. Here, we provide evidence for the role of Myo X in Netrin-1-DCC-regulated axon development in developing mouse neocortex. The knockout (KO) or knockdown (KD) of Myo X in cortical neurons of embryonic mouse brain impairs axon initiation and contralateral branching/targeting. Similar axon deficits are detected in Netrin-1-KO or DCC-KD cortical neurons. Further proteomic analysis of Myo X binding proteins identifies KIF13B (a kinesin family motor protein). The Myo X interaction with KIF13B is induced by Netrin-1. Netrin-1 promotes anterograde transportation of Myo X into axons in a KIF13B-dependent manner. KIF13B-KD cortical neurons exhibit similar axon deficits. Together, these results reveal Myo X-KIF13B as a critical pathway for Netrin-1-promoted axon initiation and branching/targeting.SIGNIFICANCE STATEMENT Netrin-1 increases Myosin X (Myo X) interaction with KIF13B, and thus promotes axonal delivery of Myo X and axon initiation and contralateral branching in developing cerebral neurons, revealing unrecognized functions and mechanisms underlying Netrin-1 regulation of axon development.
Subject(s)
Axons/physiology , Kinesins/physiology , Membrane Proteins/physiology , Myosins/physiology , Netrin-1/physiology , Animals , Cells, Cultured , Cerebral Cortex/cytology , Cerebral Cortex/growth & development , DCC Receptor/genetics , DCC Receptor/physiology , Female , Kinesins/genetics , Male , Membrane Proteins/genetics , Mice , Mice, Inbred C57BL , Mice, Knockout , Myosins/genetics , Neocortex/cytology , Neocortex/growth & development , Netrin-1/genetics , PregnancyABSTRACT
Amyloid-ß (Aß) deposition occurs years before cognitive symptoms appear and is considered a cause of Alzheimer's disease (AD). The imbalance of Aß production and clearance leads to Aß accumulation and Aß deposition. Increasing evidence indicates an important role of astrocytes, the most abundant cell type among glial cells in the brain, in Aß clearance. We explored the role of low-density lipoprotein receptor-related protein 4 (LRP4), a member of the LDLR family, in AD pathology. We show that Lrp4 is specifically expressed in astrocytes and its levels in astrocytes were higher than those of Ldlr and Lrp1, both of which have been implicated in Aß uptake. LRP4 was reduced in postmortem brain tissues of AD patients. Genetic deletion of the Lrp4 gene augmented Aß plaques in 5xFAD male mice, an AD mouse model, and exacerbated the deficits in neurotransmission, synchrony between the hippocampus and PFC, and cognition. Mechanistically, LRP4 promotes Aß uptake by astrocytes likely by interacting with ApoE. Together, our study demonstrates that astrocytic LRP4 plays an important role in Aß pathology and cognitive function.SIGNIFICANCE STATEMENT This study investigates how astrocytes, a type of non-nerve cells in the brain, may contribute to Alzheimer's disease (AD) development. We demonstrate that the low-density lipoprotein receptor-related protein 4 (LRP4) is reduced in the brain of AD patients. Mimicking the reduced levels in an AD mouse model exacerbates cognitive impairment and increases amyloid aggregates that are known to damage the brain. We show that LRP4 could promote the clearance of amyloid protein by astrocytes. Our results reveal a previously unappreciated role of LRP4 in AD development.
Subject(s)
Alzheimer Disease/metabolism , Amyloid beta-Peptides/metabolism , Astrocytes/metabolism , Brain/metabolism , LDL-Receptor Related Proteins/metabolism , Alzheimer Disease/pathology , Animals , Astrocytes/pathology , Brain/pathology , Disease Models, Animal , Female , Humans , LDL-Receptor Related Proteins/genetics , Male , Mice , Plaque, Amyloid/metabolism , Plaque, Amyloid/pathologyABSTRACT
Neuregulin3 (NRG3) is a growth factor of the neuregulin (NRG) family and a risk gene of various severe mental illnesses including schizophrenia, bipolar disorders, and major depression. However, the physiological function of NRG3 remains poorly understood. Here we show that loss of Nrg3 in GFAP-Nrg3f/f mice increased glutamatergic transmission, but had no effect on GABAergic transmission. These phenotypes were observed in Nex-Nrg3f/f mice, where Nrg3 was specifically knocked out in pyramidal neurons, indicating that Nrg3 regulates glutamatergic transmission by a cell-autonomous mechanism. Consequently, in the absence of Nrg3 in pyramidal neurons, mutant mice displayed various behavioral deficits related to mental illnesses. We show that the Nrg3 mutation decreased paired-pulse facilitation, increased decay of NMDAR currents when treated with MK801, and increased minimal stimulation-elicited response, providing evidence that the Nrg3 mutation increases glutamate release probability. Notably, Nrg3 is a presynaptic protein that regulates the SNARE-complex assembly. Finally, increased Nrg3 levels, as observed in patients with severe mental illnesses, suppressed glutamatergic transmission. Together, these observations indicate that, unlike the prototype Nrg1, the effect of which is mediated by activating ErbB4 in interneurons, Nrg3 is critical in controlling glutamatergic transmission by regulating the SNARE complex at the presynaptic terminals, identifying a function of Nrg3 and revealing a pathophysiological mechanism for hypofunction of the glutamatergic pathway in Nrg3-related severe mental illnesses.
Subject(s)
Glutamic Acid/metabolism , Intracellular Signaling Peptides and Proteins/metabolism , SNARE Proteins/metabolism , Animals , Behavior, Animal/physiology , Intracellular Signaling Peptides and Proteins/genetics , Mental Disorders/genetics , Mice , Mice, Transgenic , Neuregulins , Pyramidal Cells/metabolismABSTRACT
Neurotrophic factor NRG1 and its receptor ErbB4 play a role in GABAergic circuit assembly during development. ErbB4 null mice possess fewer interneurons, have decreased GABA release, and show impaired behavior in various paradigms. In addition, NRG1 and ErbB4 have also been implicated in regulating GABAergic transmission and plasticity in matured brains. However, current ErbB4 mutant strains are unable to determine whether phenotypes in adult mutant mice result from abnormal neural development. This important question, a glaring gap in understanding NRG1-ErbB4 function, was addressed by using two strains of mice with temporal control of ErbB4 deletion and expression, respectively. We found that ErbB4 deletion in adult mice impaired behavior and GABA release but had no effect on neuron numbers and morphology. On the other hand, some deficits due to the ErbB4 null mutation during development were alleviated by restoring ErbB4 expression at the adult stage. Together, our results indicate a critical role of NRG1-ErbB4 signaling in GABAergic transmission and behavior in adulthood and suggest that restoring NRG1-ErbB4 signaling at the postdevelopmental stage might benefit relevant brain disorders.
Subject(s)
Behavior, Animal , Brain/pathology , Interneurons/pathology , Neuregulin-1/metabolism , Receptor, ErbB-4/physiology , Synapses/physiology , Synaptic Transmission , Animals , Brain/metabolism , Interneurons/metabolism , Mice , Mice, Knockout , Neuregulin-1/genetics , Signal Transduction , gamma-Aminobutyric Acid/metabolismABSTRACT
Fear learning and memory are vital for livings to survive, dysfunctions in which have been implicated in various neuropsychiatric disorders. Appropriate neuronal activation in amygdala is critical for fear memory. However, the underlying regulatory mechanisms are not well understood. Here we report that Neogenin, a DCC (deleted in colorectal cancer) family receptor, which plays important roles in axon navigation and adult neurogenesis, is enriched in excitatory neurons in BLA (Basolateral amygdala). Fear memory is impaired in male Neogenin mutant mice. The number of cFos+ neurons in response to tone-cued fear training was reduced in mutant mice, indicating aberrant neuronal activation in the absence of Neogenin. Electrophysiological studies show that Neogenin mutation reduced the cortical afferent input to BLA pyramidal neurons and compromised both induction and maintenance of Long-Term Potentiation evoked by stimulating cortical afferent, suggesting a role of Neogenin in synaptic plasticity. Concomitantly, there was a reduction in spine density and in frequency of miniature excitatory postsynaptic currents (mEPSCs), but not miniature inhibitory postsynaptic currents, suggesting a role of Neogenin in forming excitatory synapses. Finally, ablating Neogenin in the BLA in adult male mice impaired fear memory likely by reducing mEPSC frequency in BLA excitatory neurons. These results reveal an unrecognized function of Neogenin in amygdala for information processing by promoting and maintaining neurotransmission and synaptic plasticity and provide insight into molecular mechanisms of neuronal activation in amygdala.SIGNIFICANCE STATEMENT Appropriate neuronal activation in amygdala is critical for information processing. However, the underlying regulatory mechanisms are not well understood. Neogenin is known to regulate axon navigation and adult neurogenesis. Here we show that it is critical for neurotransmission and synaptic plasticity in the amygdala and thus fear memory by using a combination of genetic, electrophysiological, behavioral techniques. Our studies identify a novel function of Neogenin and provide insight into molecular mechanisms of neuronal activation in amygdala for fear processing.
Subject(s)
Basolateral Nuclear Complex/metabolism , Fear/physiology , Learning/physiology , Membrane Proteins/genetics , Membrane Proteins/metabolism , Neurons/metabolism , Animals , Excitatory Postsynaptic Potentials/physiology , Fear/psychology , Male , Mice , Mice, Transgenic , Organ Culture TechniquesABSTRACT
During aging, acetylcholine receptor (AChR) clusters become fragmented and denervated at the neuromuscular junction (NMJ). Underpinning molecular mechanisms are not well understood. We showed that LRP4, a receptor for agrin and critical for NMJ formation and maintenance, was reduced at protein level in aged mice, which was associated with decreased MuSK tyrosine phosphorylation, suggesting compromised agrin-LRP4-MuSK signaling in aged muscles. Transgenic expression of LRP4 in muscles alleviated AChR fragmentation and denervation and improved neuromuscular transmission in aged mice. LRP4 ubiquitination was augmented in aged muscles, suggesting increased LRP4 degradation as a mechanism for reduced LRP4. We found that sarcoglycan α (SGα) interacted with LRP4 and delayed LRP4 degradation in cotransfected cells. AAV9-mediated expression of SGα in muscles mitigated AChR fragmentation and denervation and improved neuromuscular transmission in aged mice. These observations support a model where compromised agrin-LRP4-MuSK signaling serves as a pathological mechanism of age-related NMJ decline and identify a novel function of SGα in stabilizing LRP4 for NMJ stability in aged mice.SIGNIFICANCE STATEMENT This study provides evidence that LRP4, a receptor of agrin that is critical for NMJ formation and maintenance, is reduced at protein level in aged muscles. Transgenic expression of LRP4 in muscles ameliorates AChR fragmentation and denervation and improves neuromuscular transmission in aged mice, demonstrating a critical role of the agrin-LRP4-MuSK signaling. Our study also reveals a novel function of SGα to prevent LRP4 degradation in aged muscles. Finally, we show that NMJ decline in aged mice can be mitigated by AAV9-mediated expression of SGα in muscles. These observations provide insight into pathological mechanisms of age-related NMJ decline and suggest that improved agrin-LRP4-MuSK signaling may be a target for potential therapeutic intervention.
Subject(s)
Aging , Muscle, Skeletal/metabolism , Neuromuscular Junction/metabolism , Receptors, Cholinergic/metabolism , Receptors, LDL/metabolism , Sarcoglycans/metabolism , Animals , Female , LDL-Receptor Related Proteins , Male , Mice, Inbred C57BL , Mice, Transgenic , Muscle, Skeletal/innervation , Phosphorylation , Receptor Protein-Tyrosine Kinases/metabolismABSTRACT
The development of highly efficient and durable alkaline hydrogen evolution reaction (HER) catalysts is crucial for achieving high-performance practical anion exchange membrane water electrolyzer (AEMWE) at ampere-level current density. Herein, we report a design concept by employing Ga single atoms as an electronic bridge to stabilize the Ru clusters for boosting alkaline HER performance in practical AEMWE. Experimental and theoretical results collectively reveal that the bridged Ga sites trigger strong metal-support interaction for the homogeneous distribution of Ru clusters with high density, as well as optimize the Ru-H bond strength due to the electron transfer between Ru and Ga for enhanced intrinsic HER activity. Moreover, the oxophilic Ga sites near the Ru clusters tend to adsorb the hydroxyl species and accelerate the water dissociation for sufficient proton supplement in an alkaline medium. The Ru-GaSA/N-C catalyst exhibits a low overpotential of 4 ± 1 mV (10 mA cm-2) and high mass activity of 9.3 ± 0.5 A mg-1Ru at -0.05 V vs RHE. In particular, the Ru-GaSA/N-C-based AEMWE in 1 M KOH delivers a voltage of only 1.74 V to reach an industrial current density of 1 A cm-2, and can steadily operate at 1 A cm-2 for more than 170 h.
ABSTRACT
Trafficking of α-Amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA) receptors (AMPARs), mediated by AMPAR interacting proteins, enabled neurons to maintain tuning capabilities at rest or active state. α/ß-Hydrolase domain-containing 6 (ABHD6), an endocannabinoid hydrolase, was an AMPAR auxiliary subunit found to negatively regulate the surface delivery of AMPARs. While ABHD6 was found to prevent AMPAR tetramerization in endoplasmic reticulum, ABHD6 was also reported to localize at postsynaptic site. Yet, the role of ABHD6 interacting with AMPAR at postsynaptic site, and the physiological significance of ABHD6 regulating AMPAR trafficking remains elusive. Here, we generated the ABHD6 knockout (ABHD6KO) mice and found that deletion of ABHD6 selectively enhanced AMPAR-mediated basal synaptic responses and the surface expression of postsynaptic AMPARs. Furthermore, we found that loss of ABHD6 impaired hippocampal long-term depression (LTD) and synaptic downscaling in hippocampal synapses. AMPAR internalization assays revealed that ABHD6 was essential for neuronal activity-dependent endocytosis of surface AMPARs, which is independent of ABHD6's hydrolase activity. The defects of AMPAR endocytosis and LTD are expressed as deficits in learning flexibility in ABHD6KO mice. Collectively, we demonstrated that ABHD6 is an endocytic accessory protein promoting AMPAR endocytosis, thereby contributes to the formation of LTD, synaptic downscaling and reversal learning.
Subject(s)
Hydrolases , Receptors, AMPA , Mice , Animals , Receptors, AMPA/metabolism , Hydrolases/metabolism , Neuronal Plasticity/physiology , Learning , Synapses/metabolism , Endocytosis , Hippocampus/metabolism , Monoacylglycerol Lipases/metabolismABSTRACT
Thienorphine is a new nonselective partial agonist of opioid receptors, which is currently under a Phase II clinical trial in China as a new treatment for opioid dependence. In this study, we compared the effect of thienorphine with morphine on long-term potentiation (LTP) in the lateral perforant path (LPP)-granule cell synapse of the rat dentate gyrus (DG). Furthermore, the effect of thienorphine on the synaptic structure of the CA1 hippocampal region and the expression of synaptophysin was investigated. Results indicated interesting differences between thienorphine and morphine on the modulation of hippocampal synaptic plasticity. Chronic thienorphine treatment facilitated LTP in the LPP-DG cell synapses more than chronic morphine treatment. Morphometric measurement and analysis showed that chronic thienorphine administration decreased the length of the active zone and reduced the thickness of CA1 postsynaptic densities compared with the saline group (control), but were elevated compared with the morphine group. Furthermore, the expression of hippocampal synaptophysin was increased with chronic thienorphine administration but reduced with chronic morphine treatment. Taken together, our study clearly demonstrates that chronic thienorphine treatment enhances LTP, modulates hippocampal synaptic structure, and increases the expression of hippocampal synaptophysin. Therefore, further study is warranted to investigate thienorphine as a new treatment for opioid dependence.
Subject(s)
Buprenorphine/analogs & derivatives , Dentate Gyrus/drug effects , Long-Term Potentiation/drug effects , Narcotic Antagonists/pharmacology , Post-Synaptic Density/drug effects , Animals , Buprenorphine/administration & dosage , Buprenorphine/pharmacology , CA1 Region, Hippocampal/drug effects , CA1 Region, Hippocampal/metabolism , CA1 Region, Hippocampal/physiology , Dentate Gyrus/physiology , Male , Morphine/pharmacology , Narcotic Antagonists/administration & dosage , Post-Synaptic Density/physiology , Post-Synaptic Density/ultrastructure , Rats , Rats, Wistar , Synaptophysin/genetics , Synaptophysin/metabolismABSTRACT
BACKGROUND: Synapses are the connections between neurons in the central nervous system (CNS) or between neurons and other excitable cells in the peripheral nervous system (PNS), where electrical or chemical signals rapidly travel through one cell to another with high spatial precision. Synaptic analysis, based on synapse numbers and fine morphology, is the basis for understanding neurological functions and diseases. Manual analysis of synaptic structures in electron microscopy (EM) images is often limited by low efficiency and subjective bias. NEW METHOD: We developed a multifunctional synaptic analysis system based on several advanced deep learning (DL) models. The system achieved synapse counting in low-magnification EM images and synaptic ultrastructure analysis in high-magnification EM images. RESULTS: The synapse counting system based on ResNet18 and a Faster R-CNN model had a mean average precision (mAP) of 92.55%. For synaptic ultrastructure analysis, the Faster R-CNN model based on ResNet50 achieved a mAP of 91.60%, the DeepLab v3 + model based on ResNet50 enabled high performance in presynaptic and postsynaptic membrane segmentation with a global accuracy of 0.9811, and the Faster R-CNN model based on ResNet18 achieved a mAP of 91.41% for synaptic vesicle detection. CONCLUSIONS: The proposed multifunctional synaptic analysis system may help to overcome the experimental bias inherent in manual analysis, thereby facilitating EM image-based synaptic function studies.
Subject(s)
Deep Learning , Synapses/physiology , Microscopy, Electron , Synaptic Vesicles , Neurons/physiologyABSTRACT
The study investigated the effects of feed efficiency (residual feed intake, RFI and residual intake and gain, RIG) on the production performance of small-sized meat ducks. Ninety ducks with intermediate and extreme (high and low) RFI values were selected from 1,083 male ducks of similar body weight, and the 3 groups were then redivided according to RIG. For both efficiency measures, the feed conversion ratio (FCR) and average daily feed intake (ADFI) of efficient ducks were significantly lower than those of inefficient ducks (P < 0.05), while the residual body weight gain (RG) was significantly higher in efficient ducks (P < 0.05). Inefficient-RFI animals showed greater skin fat yield (P < 0.05), but no other differences in carcass traits were observed (P > 0.05). RIG had positive effects on the pH1 value of the breast muscle (P < 0.05), but feed efficiency did not affect the other meat quality traits (P > 0.05). With regard to blood biochemical parameters, efficient ducks had significantly lower triglycerides (TG) (P < 0.05). Correlation analysis demonstrated that RFI was positively correlated with average daily feed intake and feed conversion ratio (P < 0.05), while RIG exhibited a strong negative correlation with both (P < 0.05). The average daily body weight gain was positively correlated with RIG (P < 0.05). RIG had a positive effect on the pH1 value of the breast muscle (P < 0.05). Furthermore, triglyceride and high-density lipoprotein cholesterol levels correlated with both efficiency classifications (P < 0.05). Overall, the efficiency measures did not affect the carcass and meat quality of small-sized meat ducks but could identify ducks with lower feed consumption and fast growth.
Subject(s)
Animal Feed , Ducks , Male , Animals , Ducks/physiology , Animal Feed/analysis , Chickens , Eating/physiology , Meat/analysis , Phenotype , Body Weight/genetics , Weight GainABSTRACT
N-methyl-D-aspartate receptors (NMDARs) are essential for excitatory neurotransmission and synaptic plasticity. GluN2A and GluN2B, two predominant Glu2N subunits of NMDARs in the hippocampus and the cortex, display distinct clustered distribution patterns and mobility at synaptic and extrasynaptic sites. However, how GluN2A clusters are specifically organized and stabilized remains poorly understood. Here, we found that the previously reported GluN2A-specific binding partner Rabphilin-3A (Rph3A) has the ability to undergo phase separation, which relies on arginine residues in its N-terminal domain. Rph3A phase separation promotes GluN2A clustering by binding GluN2A's C-terminal domain. A complex formed by Rph3A, GluN2A, and the scaffolding protein PSD95 promoted Rph3A phase separation. Disrupting Rph3A's phase separation suppressed the synaptic and extrasynaptic surface clustering, synaptic localization, stability, and synaptic response of GluN2A in hippocampal neurons. Together, our results reveal the critical role of Rph3A phase separation in determining the organization and stability of GluN2A in the neuronal surface.
Subject(s)
Hippocampus , Neurons , Receptors, N-Methyl-D-Aspartate , Synapses , Adaptor Proteins, Signal Transducing/metabolism , Hippocampus/metabolism , Receptors, N-Methyl-D-Aspartate/genetics , Receptors, N-Methyl-D-Aspartate/metabolism , Synapses/genetics , Synapses/metabolism , Vesicular Transport Proteins/metabolism , Neurons/metabolism , Rabphilin-3AABSTRACT
Heat perception enables acute avoidance responses to prevent tissue damage and maintain body thermal homeostasis. Unlike other modalities, how heat signals are processed in the spinal cord remains unclear. By single-cell gene profiling, we identified ErbB4, a transmembrane tyrosine kinase, as a novel marker of heat-sensitive spinal neurons in mice. Ablating spinal ErbB4+ neurons attenuates heat sensation. These neurons receive monosynaptic inputs from TRPV1+ nociceptors and form excitatory synapses onto target neurons. Activation of ErbB4+ neurons enhances the heat response, while inhibition reduces the heat response. We showed that heat sensation is regulated by NRG1, an activator of ErbB4, and it involves dynamic activity of the tyrosine kinase that promotes glutamatergic transmission. Evidence indicates that the NRG1-ErbB4 signaling is also engaged in hypersensitivity of pathological pain. Together, these results identify a spinal neuron connection consisting of ErbB4+ neurons for heat sensation and reveal a regulatory mechanism by the NRG1-ErbB4 signaling.
Subject(s)
Hot Temperature , Neuregulin-1 , Neurons , Thermosensing , Animals , Mice , Neuregulin-1/pharmacology , Neurons/physiology , Receptor, ErbB-4/geneticsABSTRACT
Dopamine (DA) transmission is critical to motivation, movement, and emotion. Unlike glutamatergic and GABAergic synapses, the development of DA synapses is less understood. We show that bassoon (BSN) clusters along DA axons in the core of nucleus accumbens (NAcc) were increased in neonatal stages and reduced afterward, suggesting DA synapse elimination. Remarkably, DA neuron-specific ablating neuregulin 3 (NRG3), a protein whose levels correlate with BSN clusters, increased the clusters and impaired DA release and behaviors related to DA transmission. An unbiased screen of transmembrane proteins with the extracellular domain (ECD) of NRG3 identified Caspr3 (contactin associate-like protein 3) as a binding partner. Caspr3 was enriched in striatal medium spiny neurons (MSNs). NRG3 and Caspr3 interact in trans, which was blocked by Caspr3-ECD. Caspr3 null mice displayed phenotypes similar to those in DAT-Nrg3f/f mice in DA axonal BSN clusters and DA transmission. Finally, in vivo disruption of the NRG3-Caspr3 interaction increased BSN clusters. Together, these results demonstrate that DA synapse development is controlled by trans interaction between NRG3 in DA neurons and Caspr3 in MSNs, identifying a novel pair of cell adhesion molecules for brain circuit wiring.
Subject(s)
Corpus Striatum , Dopamine , Dopaminergic Neurons/cytology , Membrane Proteins/physiology , Nerve Tissue Proteins/physiology , Neuregulins/physiology , Animals , Corpus Striatum/cytology , Mice , Mice, Knockout , SynapsesABSTRACT
The excitability of interneurons requires Nav1.1, the α subunit of the voltage-gated sodium channel. Nav1.1 deficiency and mutations reduce interneuron excitability, a major pathological mechanism for epilepsy syndromes. However, the regulatory mechanisms of Nav1.1 expression remain unclear. Here, we provide evidence that neddylation is critical to Nav1.1 stability. Mutant mice lacking Nae1, an obligatory component of the E1 ligase for neddylation, in parvalbumin-positive interneurons (PVINs) exhibited spontaneous epileptic seizures and premature death. Electrophysiological studies indicate that Nae1 deletion reduced PVIN excitability and GABA release and consequently increased the network excitability of pyramidal neurons (PyNs). Further analysis revealed a reduction in sodium-current density, not a change in channel property, in mutant PVINs and decreased Nav1.1 protein levels. These results suggest that insufficient neddylation in PVINs reduces Nav1.1 stability and thus the excitability of PVINs; the ensuing increased PyN activity causes seizures in mice. Consistently, Nav1.1 was found reduced by proteomic analysis that revealed abnormality in synapses and metabolic pathways. Our findings describe a role of neddylation in maintaining Nav1.1 stability for PVIN excitability and reveal what we believe is a new mechanism in the pathogenesis of epilepsy.
Subject(s)
Action Potentials , Epilepsy/metabolism , Interneurons/metabolism , NAV1.1 Voltage-Gated Sodium Channel/metabolism , Seizures/metabolism , Animals , Disease Models, Animal , Interneurons/pathology , Mice , Mice, Mutant Strains , NAV1.1 Voltage-Gated Sodium Channel/genetics , Protein Stability , Pyramidal Cells/metabolism , Pyramidal Cells/pathology , Seizures/genetics , Ubiquitin-Activating Enzymes/deficiency , Ubiquitin-Activating Enzymes/metabolismABSTRACT
As a new kind of green solvents for potential replacement of traditional volatile organic compounds, deep eutectic solvents (DESs) have been attracting more and more attention in various applications. In this work, three types of hydrophobic DESs were synthesized by simple mixing of trioctylmethyl ammonium chloride (used as hydrogen bond acceptor) with decanoic acid, ketoprofen and gemfibrozil (hydrogen bond donors), respectively, at different molar ratios. In order to evaluate the solvent characteristics of these DESs, some of the physical properties such as melting point, density, viscosity, and water contact angle were determined. Then, these hydrophobic DESs were used for the vortex-assisted liquid-liquid microextraction of bisphenol-type contaminants in water, followed by quantitative determination of bisphenols contents with high performance liquid chromatography (HPLC-FLD) coupled with fluorescence detection. For this purpose, four bisphenols, namely, 2, 2-bis(4-hydroxydiphenyl)propane (BPA), 2, 2-bis (4-hydroxyphenyl)butane (BPB), 4, 4'-(1-phenylethylidene)bisphenol (BPAP) and 4, 4'-cyclohexylidenebisphenol (BPZ) were selected as model contaminants. It was found that the enrichment factors of the proposed method were in the range from 97 to 112, depending on the structure of the analytes. Under optimal experimental conditions, the linearity ranges of the method varied from 0.3 to 700 µg L-1 with linear correlation coefficients (R2) higher than 0.996. The limit of detections (LODs) and limit of quantifications (LOQs) were in the range of 0.3-0.5 µg L-1 and 0.06-0.08 µg L-1, respectively. Furthermore, the developed method was successfully used in the extraction and determination of four bisphenols from food-contacted plastic samples.