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Price MS, Moore TI, Venkatachalam K. Intracellular Lactate Dynamics Reveal the Metabolic Diversity of Drosophila Glutamatergic Neurons. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.02.26.582095. [PMID: 38464270 PMCID: PMC10925175 DOI: 10.1101/2024.02.26.582095] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/12/2024]
Abstract
Lactate, an intermediary between glycolysis and mitochondrial oxidative phosphorylation, reflects the metabolic state of neurons. Here, we utilized a genetically-encoded lactate FRET biosensor to uncover subpopulations of distinct metabolic states among Drosophila glutamatergic neurons. Neurons within specific subpopulations exhibited correlated lactate flux patterns that stemmed from inherent cellular properties rather than neuronal interconnectivity. Further, individual neurons exhibited consistent patterns of lactate flux over time such that stimulus-evoked changes in lactate were correlated with pre-treatment fluctuations. Leveraging these temporal autocorrelations, deep-learning models accurately predicted post-stimulus responses from pre-stimulus fluctuations. These findings point to the existence of distinct neuronal subpopulations, each characterized by unique lactate dynamics, and raise the possibility that neurons with correlated metabolic activities might synchronize across different neural circuits. Such synchronization, rooted in neuronal metabolic states, could influence information processing in the brain.
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Affiliation(s)
- Matthew S. Price
- Department of Integrative Biology and Pharmacology, McGovern Medical School at the University of Texas Health Sciences Center (UTHealth), Houston, TX, USA
- Neuroscience Graduate Program, The University of Texas MD Anderson Cancer Center UTHealth Houston Graduate School of Biomedical Sciences
- Molecular and Translational Biology Graduate Program, The University of Texas MD Anderson Cancer Center UTHealth Houston Graduate School of Biomedical Sciences
| | - Travis I. Moore
- Department of Integrative Biology and Pharmacology, McGovern Medical School at the University of Texas Health Sciences Center (UTHealth), Houston, TX, USA
- Molecular and Translational Biology Graduate Program, The University of Texas MD Anderson Cancer Center UTHealth Houston Graduate School of Biomedical Sciences
| | - Kartik Venkatachalam
- Department of Integrative Biology and Pharmacology, McGovern Medical School at the University of Texas Health Sciences Center (UTHealth), Houston, TX, USA
- Neuroscience Graduate Program, The University of Texas MD Anderson Cancer Center UTHealth Houston Graduate School of Biomedical Sciences
- Molecular and Translational Biology Graduate Program, The University of Texas MD Anderson Cancer Center UTHealth Houston Graduate School of Biomedical Sciences
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2
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Justs KA, Sempertegui S, Riboul DV, Oliva CD, Durbin RJ, Crill S, Stawarski M, Su C, Renden RB, Fily Y, Macleod GT. Mitochondrial phosphagen kinases support the volatile power demands of motor nerve terminals. J Physiol 2023; 601:5705-5732. [PMID: 37942946 PMCID: PMC10841428 DOI: 10.1113/jp284872] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2023] [Accepted: 10/17/2023] [Indexed: 11/10/2023] Open
Abstract
Motor neurons are the longest neurons in the body, with axon terminals separated from the soma by as much as a meter. These terminals are largely autonomous with regard to their bioenergetic metabolism and must burn energy at a high rate to sustain muscle contraction. Here, through computer simulation and drawing on previously published empirical data, we determined that motor neuron terminals in Drosophila larvae experience highly volatile power demands. It might not be surprising then, that we discovered the mitochondria in the motor neuron terminals of both Drosophila and mice to be heavily decorated with phosphagen kinases - a key element in an energy storage and buffering system well-characterized in fast-twitch muscle fibres. Knockdown of arginine kinase 1 (ArgK1) in Drosophila larval motor neurons led to several bioenergetic deficits, including mitochondrial matrix acidification and a faster decline in the cytosol ATP to ADP ratio during axon burst firing. KEY POINTS: Neurons commonly fire in bursts imposing highly volatile demands on the bioenergetic machinery that generates ATP. Using a computational approach, we built profiles of presynaptic power demand at the level of single action potentials, as well as the transition from rest to sustained activity. Phosphagen systems are known to buffer ATP levels in muscles and we demonstrate that phosphagen kinases, which support such phosphagen systems, also localize to mitochondria in motor nerve terminals of fruit flies and mice. By knocking down phosphagen kinases in fruit fly motor nerve terminals, and using fluorescent reporters of the ATP:ADP ratio, lactate, pH and Ca2+ , we demonstrate a role for phosphagen kinases in stabilizing presynaptic ATP levels. These data indicate that the maintenance of phosphagen systems in motor neurons, and not just muscle, could be a beneficial initiative in sustaining musculoskeletal health and performance.
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Affiliation(s)
- Karlis A. Justs
- Integrative Biology and Neuroscience Graduate Program, Florida Atlantic University, Jupiter, FL 33458, USA
| | - Sergio Sempertegui
- Department of Physics, College of Science, Florida Atlantic University, Boca Raton, FL, 33431, USA
| | - Danielle V. Riboul
- Integrative Biology and Neuroscience Graduate Program, Florida Atlantic University, Jupiter, FL 33458, USA
| | - Carlos D. Oliva
- Wilkes Honors College, Florida Atlantic University, Jupiter, FL 33458, USA
| | - Ryan J. Durbin
- Department of Physiology and Cell Biology, University of Nevada, Reno School of Medicine, Reno, NV, 89557
| | - Sarah Crill
- Wilkes Honors College, Florida Atlantic University, Jupiter, FL 33458, USA
| | - Michal Stawarski
- Wilkes Honors College, Florida Atlantic University, Jupiter, FL 33458, USA
| | - Chenchen Su
- Wilkes Honors College, Florida Atlantic University, Jupiter, FL 33458, USA
| | - Robert B. Renden
- Department of Physiology and Cell Biology, University of Nevada, Reno School of Medicine, Reno, NV, 89557
| | - Yaouen Fily
- Wilkes Honors College, Florida Atlantic University, Jupiter, FL 33458, USA
| | - Gregory T. Macleod
- Wilkes Honors College, Florida Atlantic University, Jupiter, FL 33458, USA
- Institute for Human Health & Disease Intervention, Florida Atlantic University, Jupiter, FL 33458, USA
- Stiles-Nicholson Brain Institute, Florida Atlantic University, Jupiter, FL 33458, USA
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3
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Huang Z, Sun Z, Liu J, Ju X, Xia H, Yang Y, Chen K, Wang Q. Insect transient receptor potential vanilloid channels as potential targets of insecticides. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2023; 148:104899. [PMID: 37531974 DOI: 10.1016/j.dci.2023.104899] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/2023] [Revised: 07/28/2023] [Accepted: 07/30/2023] [Indexed: 08/04/2023]
Abstract
Chordotonal organs are miniature sensory organs present in insects. Chordotonal organs depend on transient receptor potential (TRP) channels. Transient receptor potential vanilloid (TRPV) channels are the only TRPs identified that can act as targets of insecticides. By binding with TRPV channels, insecticides targeting the chordotonal organs trigger the inflow of calcium ions, resulting in abnormal function of the chordotonal organ to achieve the goal of eliminating pests. TRPV channels are highly expressed in various developmental stages and tissue parts of insects and play an important role in the whole life history of insects. In this review, we will discuss the structure and types of TRPV channels as well as their genetic relationships in different species. We also systematically reviewed the recent progress of TRPV channels as insecticide targets, demonstrating that TRPV channels can be used as the target of new high-efficiency insecticides.
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Affiliation(s)
- Zengqing Huang
- School of Life Sciences, Jiangsu University, Zhenjiang, Jiangsu, PR China
| | - Zhonghe Sun
- School of Life Sciences, Jiangsu University, Zhenjiang, Jiangsu, PR China
| | - Jiayi Liu
- School of Medicine, Jiangsu University, Zhenjiang, Jiangsu, 212013, PR China
| | - Xiaoli Ju
- School of Medicine, Jiangsu University, Zhenjiang, Jiangsu, 212013, PR China
| | - Hengchuan Xia
- School of Life Sciences, Jiangsu University, Zhenjiang, Jiangsu, PR China
| | - Yanhua Yang
- School of Life Sciences, Jiangsu University, Zhenjiang, Jiangsu, PR China
| | - Keping Chen
- School of Life Sciences, Jiangsu University, Zhenjiang, Jiangsu, PR China
| | - Qiang Wang
- School of Life Sciences, Jiangsu University, Zhenjiang, Jiangsu, PR China.
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Hao H, Song L, Zhang L. Wolfram syndrome 1 regulates sleep in dopamine receptor neurons by modulating calcium homeostasis. PLoS Genet 2023; 19:e1010827. [PMID: 37399203 DOI: 10.1371/journal.pgen.1010827] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2022] [Accepted: 06/13/2023] [Indexed: 07/05/2023] Open
Abstract
Sleep disruptions are quite common in psychological disorders, but the underlying mechanism remains obscure. Wolfram syndrome 1 (WS1) is an autosomal recessive disease mainly characterized by diabetes insipidus/mellitus, neurodegeneration and psychological disorders. It is caused by loss-of function mutations of the WOLFRAM SYNDROME 1 (WFS1) gene, which encodes an endoplasmic reticulum (ER)-resident transmembrane protein. Heterozygous mutation carriers do not develop WS1 but exhibit 26-fold higher risk of having psychological disorders. Since WS1 patients display sleep abnormalities, we aimed to explore the role of WFS1 in sleep regulation so as to help elucidate the cause of sleep disruptions in psychological disorders. We found in Drosophila that knocking down wfs1 in all neurons and wfs1 mutation lead to reduced sleep and dampened circadian rhythm. These phenotypes are mainly caused by lack of wfs1 in dopamine 2-like receptor (Dop2R) neurons which act to promote wake. Consistently, the influence of wfs1 on sleep is blocked or partially rescued by inhibiting or knocking down the rate-limiting enzyme of dopamine synthesis, suggesting that wfs1 modulates sleep via dopaminergic signaling. Knocking down wfs1 alters the excitability of Dop2R neurons, while genetic interactions reveal that lack of wfs1 reduces sleep via perturbation of ER-mediated calcium homeostasis. Taken together, we propose a role for wfs1 in modulating the activities of Dop2R neurons by impinging on intracellular calcium homeostasis, and this in turn influences sleep. These findings provide a potential mechanistic insight for pathogenesis of diseases associated with WFS1 mutations.
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Affiliation(s)
- Huanfeng Hao
- Key Laboratory of Molecular Biophysics of Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Li Song
- Key Laboratory of Molecular Biophysics of Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Luoying Zhang
- Key Laboratory of Molecular Biophysics of Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei, China
- Hubei Province Key Laboratory of Oral and Maxillofacial Development and Regeneration, Wuhan, Hubei, China
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Karagas NE, Gupta R, Rastegari E, Tan KL, Leung HH, Bellen HJ, Venkatachalam K, Wong CO. Loss of Activity-Induced Mitochondrial ATP Production Underlies the Synaptic Defects in a Drosophila Model of ALS. J Neurosci 2022; 42:8019-8037. [PMID: 36261266 PMCID: PMC9617612 DOI: 10.1523/jneurosci.2456-21.2022] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2021] [Revised: 08/23/2022] [Accepted: 08/27/2022] [Indexed: 11/21/2022] Open
Abstract
Mutations in the gene encoding vesicle-associated membrane protein B (VAPB) cause a familial form of amyotrophic lateral sclerosis (ALS). Expression of an ALS-related variant of vapb (vapbP58S ) in Drosophila motor neurons results in morphologic changes at the larval neuromuscular junction (NMJ) characterized by the appearance of fewer, but larger, presynaptic boutons. Although diminished microtubule stability is known to underlie these morphologic changes, a mechanism for the loss of presynaptic microtubules has been lacking. By studying flies of both sexes, we demonstrate the suppression of vapbP58S -induced changes in NMJ morphology by either a loss of endoplasmic reticulum (ER) Ca2+ release channels or the inhibition Ca2+/calmodulin (CaM)-activated kinase II (CaMKII). These data suggest that decreased stability of presynaptic microtubules at vapbP58S NMJs results from hyperactivation of CaMKII because of elevated cytosolic [Ca2+]. We attribute the Ca2+ dyshomeostasis to delayed extrusion of cytosolic Ca2+ Suggesting that this defect in Ca2+ extrusion arose from an insufficient response to the bioenergetic demand of neural activity, depolarization-induced mitochondrial ATP production was diminished in vapbP58S neurons. These findings point to bioenergetic dysfunction as a potential cause for the synaptic defects in vapbP58S -expressing motor neurons.SIGNIFICANCE STATEMENT Whether the synchrony between the rates of ATP production and demand is lost in degenerating neurons remains poorly understood. We report that expression of a gene equivalent to an amyotrophic lateral sclerosis (ALS)-causing variant of vesicle-associated membrane protein B (VAPB) in fly neurons decouples mitochondrial ATP production from neuronal activity. Consequently, levels of ATP in mutant neurons are unable to keep up with the bioenergetic burden of neuronal activity. Reduced rate of Ca2+ extrusion, which could result from insufficient energy to power Ca2+ ATPases, results in the accumulation of residual Ca2+ in mutant neurons and leads to alterations in synaptic vesicle (SV) release and synapse development. These findings suggest that synaptic defects in a model of ALS arise from the loss of activity-induced ATP production.
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Affiliation(s)
- Nicholas E Karagas
- Department of Integrative Biology and Pharmacology, McGovern Medical School at the University of Texas Health Sciences Center, Houston, Texas 77030
- Graduate Program in Biochemistry and Cell Biology, MD Anderson Cancer Center and University of Texas Health Sciences Center Graduate School of Biomedical Sciences, Houston, TX, 77030
| | - Richa Gupta
- Department of Integrative Biology and Pharmacology, McGovern Medical School at the University of Texas Health Sciences Center, Houston, Texas 77030
| | - Elham Rastegari
- Department of Integrative Biology and Pharmacology, McGovern Medical School at the University of Texas Health Sciences Center, Houston, Texas 77030
| | - Kai Li Tan
- Departments of Molecular and Human Genetics and Neuroscience, Baylor College of Medicine, Houston, TX 77030
- Graduate Program in Developmental Biology, Baylor College of Medicine, Houston, Texas 77030
- Duncan Neurological Research Institute, Texas Children Hospital, Houston, Texas 77030
| | - Ho Hang Leung
- Department of Biological Sciences, Rutgers University, Newark, New Jersey 07102
| | - Hugo J Bellen
- Departments of Molecular and Human Genetics and Neuroscience, Baylor College of Medicine, Houston, TX 77030
- Graduate Program in Developmental Biology, Baylor College of Medicine, Houston, Texas 77030
- Duncan Neurological Research Institute, Texas Children Hospital, Houston, Texas 77030
| | - Kartik Venkatachalam
- Department of Integrative Biology and Pharmacology, McGovern Medical School at the University of Texas Health Sciences Center, Houston, Texas 77030
- Graduate Program in Biochemistry and Cell Biology, MD Anderson Cancer Center and University of Texas Health Sciences Center Graduate School of Biomedical Sciences, Houston, TX, 77030
- Graduate Program in Neuroscience, MD Anderson Cancer Center and University of Texas Health Sciences Center Graduate School of Biomedical Sciences, Houston, TX, 77030
| | - Ching-On Wong
- Department of Biological Sciences, Rutgers University, Newark, New Jersey 07102
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Activity-dependent endoplasmic reticulum Ca 2+ uptake depends on Kv2.1-mediated endoplasmic reticulum/plasma membrane junctions to promote synaptic transmission. Proc Natl Acad Sci U S A 2022; 119:e2117135119. [PMID: 35862456 PMCID: PMC9335237 DOI: 10.1073/pnas.2117135119] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
The endoplasmic reticulum (ER) extends throughout the neuron as a continuous organelle, and its dysfunction is associated with several neurological disorders. During electrical activity, the ER takes up Ca2+ from the cytosol, which has been shown to support synaptic transmission. This close choreography of ER Ca2+ uptake with electrical activity suggests functional coupling of the ER to sources of voltage-gated Ca2+ entry through an unknown mechanism. We report that a nonconducting role for Kv2.1 through its ER binding domain is necessary for ER Ca2+ uptake during neuronal activity. Loss of Kv2.1 profoundly disables neurotransmitter release without altering presynaptic voltage. This suggests that Kv2.1-mediated signaling hubs play an important neurobiological role in Ca2+ handling and synaptic transmission independent of ion conduction. The endoplasmic reticulum (ER) forms a continuous and dynamic network throughout a neuron, extending from dendrites to axon terminals, and axonal ER dysfunction is implicated in several neurological disorders. In addition, tight junctions between the ER and plasma membrane (PM) are formed by several molecules including Kv2 channels, but the cellular functions of many ER-PM junctions remain unknown. Recently, dynamic Ca2+ uptake into the ER during electrical activity was shown to play an essential role in synaptic transmission. Our experiments demonstrate that Kv2.1 channels are necessary for enabling ER Ca2+ uptake during electrical activity, as knockdown (KD) of Kv2.1 rendered both the somatic and axonal ER unable to accumulate Ca2+ during electrical stimulation. Moreover, our experiments demonstrate that the loss of Kv2.1 in the axon impairs synaptic vesicle fusion during stimulation via a mechanism unrelated to voltage. Thus, our data demonstrate that a nonconducting role of Kv2.1 exists through its binding to the ER protein VAMP-associated protein (VAP), which couples ER Ca2+ uptake with electrical activity. Our results further suggest that Kv2.1 has a critical function in neuronal cell biology for Ca2+ handling independent of voltage and reveals a critical pathway for maintaining ER lumen Ca2+ levels and efficient neurotransmitter release. Taken together, these findings reveal an essential nonclassical role for both Kv2.1 and the ER-PM junctions in synaptic transmission.
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Martelli F, Hernandes NH, Zuo Z, Wang J, Wong CO, Karagas NE, Roessner U, Rupasinghe T, Robin C, Venkatachalam K, Perry T, Batterham P, Bellen HJ. Low doses of the organic insecticide spinosad trigger lysosomal defects, elevated ROS, lipid dysregulation, and neurodegeneration in flies. eLife 2022; 11:73812. [PMID: 35191376 PMCID: PMC8863376 DOI: 10.7554/elife.73812] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2021] [Accepted: 01/28/2022] [Indexed: 12/14/2022] Open
Abstract
Large-scale insecticide application is a primary weapon in the control of insect pests in agriculture. However, a growing body of evidence indicates that it is contributing to the global decline in population sizes of many beneficial insect species. Spinosad emerged as an organic alternative to synthetic insecticides and is considered less harmful to beneficial insects, yet its mode of action remains unclear. Using Drosophila, we show that low doses of spinosad antagonize its neuronal target, the nicotinic acetylcholine receptor subunit alpha 6 (nAChRα6), reducing the cholinergic response. We show that the nAChRα6 receptors are transported to lysosomes that become enlarged and increase in number upon low doses of spinosad treatment. Lysosomal dysfunction is associated with mitochondrial stress and elevated levels of reactive oxygen species (ROS) in the central nervous system where nAChRα6 is broadly expressed. ROS disturb lipid storage in metabolic tissues in an nAChRα6-dependent manner. Spinosad toxicity is ameliorated with the antioxidant N-acetylcysteine amide. Chronic exposure of adult virgin females to low doses of spinosad leads to mitochondrial defects, severe neurodegeneration, and blindness. These deleterious effects of low-dose exposures warrant rigorous investigation of its impacts on beneficial insects.
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Affiliation(s)
- Felipe Martelli
- School of BioSciences, The University of Melbourne, Melbourne, Australia
| | | | - Zhongyuan Zuo
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, United States
| | - Julia Wang
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, United States
| | - Ching-On Wong
- Department of Integrative Biology and Pharmacology, McGovern Medical School at the University of Texas Health Sciences Center, Houston, United States
| | - Nicholas E Karagas
- Department of Integrative Biology and Pharmacology, McGovern Medical School at the University of Texas Health Sciences Center, Houston, United States
| | - Ute Roessner
- School of BioSciences, The University of Melbourne, Melbourne, Australia
| | - Thusita Rupasinghe
- School of BioSciences, The University of Melbourne, Melbourne, Australia
| | - Charles Robin
- School of BioSciences, The University of Melbourne, Melbourne, Australia
| | - Kartik Venkatachalam
- Department of Integrative Biology and Pharmacology, McGovern Medical School at the University of Texas Health Sciences Center, Houston, United States
| | - Trent Perry
- School of BioSciences, The University of Melbourne, Melbourne, Australia
| | - Philip Batterham
- School of BioSciences, The University of Melbourne, Melbourne, Australia
| | - Hugo J Bellen
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, United States.,Neurological Research Institute, Texas Children Hospital, Houston, United States.,Howard Hughes Medical Institute, Baylor College of Medicine, Houston, United States
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8
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Mitochondria-Endoplasmic Reticulum Interplay Regulates Exo-Cytosis in Human Neuroblastoma Cells. Cells 2022; 11:cells11030514. [PMID: 35159324 PMCID: PMC8834387 DOI: 10.3390/cells11030514] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2021] [Revised: 01/23/2022] [Accepted: 01/27/2022] [Indexed: 02/04/2023] Open
Abstract
Mitochondria–endoplasmic reticulum (ER) contact sites (MERCS) have been emerging as a multifaceted subcellular region of the cell which affects several physiological and pathological mechanisms. A thus far underexplored aspect of MERCS is their contribution to exocytosis. Here, we set out to understand the role of these contacts in exocytosis and find potential mechanisms linking these structures to vesicle release in human neuroblastoma SH-SY5Y cells. We show that increased mitochondria to ER juxtaposition through Mitofusin 2 (Mfn2) knock-down resulted in a substantial upregulation of the number of MERCS, confirming the role of Mfn2 as a negative regulator of these structures. Furthermore, we report that both vesicle numbers and vesicle protein levels were decreased, while a considerable upregulation in exocytotic events upon cellular depolarization was detected. Interestingly, in Mfn2 knock-down cells, the inhibition of the inositol 1,4,5-trisphosphate receptor (IP3R) and the mitochondrial calcium (Ca2+) uniporter (MCU) restored vesicle protein content and attenuated exocytosis. We thus suggest that MERCS could be targeted to prevent increased exocytosis in conditions in which ER to mitochondria proximity is upregulated.
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Cho TS, Beigaitė E, Klein NE, Sweeney ST, Bhattacharya MRC. The Putative Drosophila TMEM184B Ortholog Tmep Ensures Proper Locomotion by Restraining Ectopic Firing at the Neuromuscular Junction. Mol Neurobiol 2022; 59:2605-2619. [PMID: 35107803 PMCID: PMC9018515 DOI: 10.1007/s12035-022-02760-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2021] [Accepted: 01/20/2022] [Indexed: 11/29/2022]
Abstract
TMEM184B is a putative seven-pass membrane protein that promotes axon degeneration after injury. TMEM184B mutation causes aberrant neuromuscular architecture and sensory and motor behavioral defects in mice. The mechanism through which TMEM184B causes neuromuscular defects is unknown. We employed Drosophila melanogaster to investigate the function of the closely related gene, Tmep (CG12004), at the neuromuscular junction. We show that Tmep is required for full adult viability and efficient larval locomotion. Tmep mutant larvae have a reduced body contraction rate compared to controls, with stronger deficits in females. In recordings from body wall muscles, Tmep mutants show substantial hyperexcitability, with many postsynaptic potentials fired in response to a single stimulation, consistent with a role for Tmep in restraining synaptic excitability. Additional branches and satellite boutons at Tmep mutant neuromuscular junctions are consistent with an activity-dependent synaptic overgrowth. Tmep is expressed in endosomes and synaptic vesicles within motor neurons, suggesting a possible role in synaptic membrane trafficking. Using RNAi knockdown, we show that Tmep is required in motor neurons for proper larval locomotion and excitability, and that its reduction increases levels of presynaptic calcium. Locomotor defects can be rescued by presynaptic knockdown of endoplasmic reticulum calcium channels or by reducing evoked release probability, further suggesting that excess synaptic activity drives behavioral deficiencies. Our work establishes a critical function for Tmep in the regulation of synaptic transmission and locomotor behavior.
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Affiliation(s)
- Tiffany S Cho
- Department of Neuroscience, University of Arizona, 1040 E 4th Street, Tucson, AZ, 85721, USA
| | - Eglė Beigaitė
- Department of Biology, University of York, York, YO10 5DD, UK.,York Biomedical Research Institute, University of York, York, YO10 5DD, UK
| | - Nathaniel E Klein
- Department of Neuroscience, University of Arizona, 1040 E 4th Street, Tucson, AZ, 85721, USA
| | - Sean T Sweeney
- Department of Biology, University of York, York, YO10 5DD, UK.,York Biomedical Research Institute, University of York, York, YO10 5DD, UK
| | - Martha R C Bhattacharya
- Department of Neuroscience, University of Arizona, 1040 E 4th Street, Tucson, AZ, 85721, USA.
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10
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Weiss S, Clamon LC, Manoim JE, Ormerod KG, Parnas M, Littleton JT. Glial ER and GAP junction mediated Ca 2+ waves are crucial to maintain normal brain excitability. Glia 2021; 70:123-144. [PMID: 34528727 DOI: 10.1002/glia.24092] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2021] [Revised: 08/29/2021] [Accepted: 08/30/2021] [Indexed: 11/08/2022]
Abstract
Astrocytes play key roles in regulating multiple aspects of neuronal function from invertebrates to humans and display Ca2+ fluctuations that are heterogeneously distributed throughout different cellular microdomains. Changes in Ca2+ dynamics represent a key mechanism for how astrocytes modulate neuronal activity. An unresolved issue is the origin and contribution of specific glial Ca2+ signaling components at distinct astrocytic domains to neuronal physiology and brain function. The Drosophila model system offers a simple nervous system that is highly amenable to cell-specific genetic manipulations to characterize the role of glial Ca2+ signaling. Here we identify a role for ER store-operated Ca2+ entry (SOCE) pathway in perineurial glia (PG), a glial population that contributes to the Drosophila blood-brain barrier. We show that PG cells display diverse Ca2+ activity that varies based on their locale within the brain. Ca2+ signaling in PG cells does not require extracellular Ca2+ and is blocked by inhibition of SOCE, Ryanodine receptors, or gap junctions. Disruption of these components triggers stimuli-induced seizure-like episodes. These findings indicate that Ca2+ release from internal stores and its propagation between neighboring glial cells via gap junctions are essential for maintaining normal nervous system function.
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Affiliation(s)
- Shirley Weiss
- The Picower Institute for Learning and Memory, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA.,Department of Physiology and Pharmacology, Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Lauren C Clamon
- The Picower Institute for Learning and Memory, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA.,Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
| | - Julia E Manoim
- Department of Physiology and Pharmacology, Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Kiel G Ormerod
- The Picower Institute for Learning and Memory, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
| | - Moshe Parnas
- Department of Physiology and Pharmacology, Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel.,Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel
| | - J Troy Littleton
- The Picower Institute for Learning and Memory, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA.,Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA.,Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
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11
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Xie Q, Ma R, Li H, Wang J, Guo X, Chen H. Advancement in research on the role of the transient receptor potential vanilloid channel in cerebral ischemic injury (Review). Exp Ther Med 2021; 22:881. [PMID: 34194559 PMCID: PMC8237269 DOI: 10.3892/etm.2021.10313] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2020] [Accepted: 05/28/2021] [Indexed: 01/04/2023] Open
Abstract
Stroke is a common critical disease occurring in middle-aged and elderly individuals, and is characterized by high morbidity, lethality and mortality. As such, it is of great concern to medical professionals. The aim of the present review was to investigate the effects of transient receptor potential vanilloid (TRPV) subtypes during cerebral ischemia in ischemia-reperfusion animal models, oxygen glucose deprivation and in other administration cell models in vitro to explore new avenues for stroke research and clinical treatments. TRPV1, TRPV2 and TRPV4 employ different methodologies by which they confer protection against cerebral ischemic injury. TRPV1 and TRPV4 are likely related to the inhibition of inflammatory reactions, neurotoxicity and cell apoptosis, thus promoting nerve growth and regulation of intracellular calcium ions (Ca2+). The mechanisms of neuroprotection of TRPV1 are the JNK pathway, N-methyl-D-aspartate (NMDA) receptor and therapeutic hypothermia. The mechanisms of neuroprotection of TRPV4 are the PI3K/Akt pathways, NMDA receptor and p38 MAPK pathway, amongst others. The mechanisms by which TRPV2 confers its protective effects are predominantly connected with the regulation of nerve growth factor, MAPK and JNK pathways, as well as JNK-dependent pathways. Thus, TRPVs have the potential for improving outcomes associated with cerebral ischemic or reperfusion injuries. The protection conferred by TRPV1 and TRPV4 is closely related to cellular Ca2+ influx, while TRPV2 has a different target and mode of action, possibly due to its expression sites. However, in light of certain contradictory research conclusions, further experimentation is required to clarify the mechanisms and specific pathways by which TRPVs act to alleviate nerve injuries.
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Affiliation(s)
- Qian Xie
- School of Pharmacy and State Key Laboratory of Characteristic Chinese Medicine Resources in Southwest China, Chengdu University of Traditional Chinese Medicine, Chengdu, Sichuan 611137, P.R. China
| | - Rong Ma
- School of Pharmacy and State Key Laboratory of Characteristic Chinese Medicine Resources in Southwest China, Chengdu University of Traditional Chinese Medicine, Chengdu, Sichuan 611137, P.R. China
| | - Hongyan Li
- School of Pharmacy and State Key Laboratory of Characteristic Chinese Medicine Resources in Southwest China, Chengdu University of Traditional Chinese Medicine, Chengdu, Sichuan 611137, P.R. China
| | - Jian Wang
- School of Pharmacy and State Key Laboratory of Characteristic Chinese Medicine Resources in Southwest China, Chengdu University of Traditional Chinese Medicine, Chengdu, Sichuan 611137, P.R. China
| | - Xiaoqing Guo
- School of Pharmacy and State Key Laboratory of Characteristic Chinese Medicine Resources in Southwest China, Chengdu University of Traditional Chinese Medicine, Chengdu, Sichuan 611137, P.R. China
| | - Hai Chen
- School of Pharmacy and State Key Laboratory of Characteristic Chinese Medicine Resources in Southwest China, Chengdu University of Traditional Chinese Medicine, Chengdu, Sichuan 611137, P.R. China
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12
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Abstract
Chemotherapy-induced peripheral neuropathy (CIPN) is a debilitating “dying back” neuropathy featuring a distal-to-proximal peripheral nerve degeneration seen in cancer patients undergoing chemotherapy. The pathogenenic mechanisms of CIPN are largely unknown. We report that in sensory neurons, the CIPN-inducing drug bortezomib caused axonopathy and disrupted mitochondria motility by increasing delta 2 tubulin (D2), the only irreversible tubulin posttranslational modification and a marker of hyper-stable microtubules. These data provide a new paradigm for the risk associated with enhanced tubulin longevity in peripheral neuropathy and suggest that targeting the enzymes regulating this tubulin modification may provide therapies that prevent the axonal injury observed in bortezomib-induced peripheral neuropathy. The pathogenesis of chemotherapy-induced peripheral neuropathy (CIPN) is poorly understood. Here, we report that the CIPN-causing drug bortezomib (Bort) promotes delta 2 tubulin (D2) accumulation while affecting microtubule stability and dynamics in sensory neurons in vitro and in vivo and that the accumulation of D2 is predominant in unmyelinated fibers and a hallmark of bortezomib-induced peripheral neuropathy (BIPN) in humans. Furthermore, while D2 overexpression was sufficient to cause axonopathy and inhibit mitochondria motility, reduction of D2 levels alleviated both axonal degeneration and the loss of mitochondria motility induced by Bort. Together, our data demonstrate that Bort, a compound structurally unrelated to tubulin poisons, affects the tubulin cytoskeleton in sensory neurons in vitro, in vivo, and in human tissue, indicating that the pathogenic mechanisms of seemingly unrelated CIPN drugs may converge on tubulin damage. The results reveal a previously unrecognized pathogenic role for D2 in BIPN that may occur through altered regulation of mitochondria motility.
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13
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Regulation of longevity by depolarization-induced activation of PLC-β-IP 3R signaling in neurons. Proc Natl Acad Sci U S A 2021; 118:2004253118. [PMID: 33859040 PMCID: PMC8072327 DOI: 10.1073/pnas.2004253118] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
We demonstrate that depolarization of Drosophila glutamatergic neurons augmented inositol trisphosphate receptor (IP3R)-dependent release of endoplasmic reticulum (ER) Ca2+, which in turn potentiated mitochondrial Ca2+ uptake and ATP production. Perturbations that induced chronic depolarization, including the expression of neurodegeneration-related transgenes, led to the diversion of released ER Ca2+ into lysosomes and an attendant shortening of animal lifespan. Thus, genetic disruption of PLC-β–IP3R signaling or lysosomal Ca2+ uptake restored longevity in animals with chronically depolarized glutamatergic neurons. Our findings point to aberrant Ca2+ signaling between the ER and lysosomes as a mechanism by which hyperexcitable glutamatergic neurons shorten animal lifespan. Mitochondrial ATP production is a well-known regulator of neuronal excitability. The reciprocal influence of plasma-membrane potential on ATP production, however, remains poorly understood. Here, we describe a mechanism by which depolarized neurons elevate the somatic ATP/ADP ratio in Drosophila glutamatergic neurons. We show that depolarization increased phospholipase-Cβ (PLC-β) activity by promoting the association of the enzyme with its phosphoinositide substrate. Augmented PLC-β activity led to greater release of endoplasmic reticulum Ca2+ via the inositol trisphosphate receptor (IP3R), increased mitochondrial Ca2+ uptake, and promoted ATP synthesis. Perturbations that decoupled membrane potential from this mode of ATP synthesis led to untrammeled PLC-β–IP3R activation and a dramatic shortening of Drosophila lifespan. Upon investigating the underlying mechanisms, we found that increased sequestration of Ca2+ into endolysosomes was an intermediary in the regulation of lifespan by IP3Rs. Manipulations that either lowered PLC-β/IP3R abundance or attenuated endolysosomal Ca2+ overload restored animal longevity. Collectively, our findings demonstrate that depolarization-dependent regulation of PLC-β–IP3R signaling is required for modulation of the ATP/ADP ratio in healthy glutamatergic neurons, whereas hyperactivation of this axis in chronically depolarized glutamatergic neurons shortens animal lifespan by promoting endolysosomal Ca2+ overload.
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14
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Parato J, Bartolini F. The microtubule cytoskeleton at the synapse. Neurosci Lett 2021; 753:135850. [PMID: 33775740 DOI: 10.1016/j.neulet.2021.135850] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2021] [Revised: 03/19/2021] [Accepted: 03/22/2021] [Indexed: 12/13/2022]
Abstract
In neurons, microtubules (MTs) provide routes for transport throughout the cell and structural support for dendrites and axons. Both stable and dynamic MTs are necessary for normal neuronal functions. Research in the last two decades has demonstrated that MTs play additional roles in synaptic structure and function in both pre- and postsynaptic elements. Here, we review current knowledge of the functions that MTs perform in excitatory and inhibitory synapses, as well as in the neuromuscular junction and other specialized synapses, and discuss the implications that this knowledge may have in neurological disease.
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Affiliation(s)
- Julie Parato
- Columbia University Medical Center, Department of Pathology & Cell Biology, 630 West 168(th)Street, P&S 15-421, NY, NY, 10032, United States; SUNY Empire State College, Department of Natural Sciences, 177 Livingston Street, Brooklyn, NY, 11201, United States
| | - Francesca Bartolini
- Columbia University Medical Center, Department of Pathology & Cell Biology, 630 West 168(th)Street, P&S 15-421, NY, NY, 10032, United States.
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15
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Saito M, Nakayama M, Fujita K, Uchida A, Yano H, Goto S, Okazawa H, Sone M. Role of the Drosophila YATA protein in the proper subcellular localization of COPI revealed by in vivo analysis. Genes Genet Syst 2021; 95:303-314. [PMID: 33583916 DOI: 10.1266/ggs.20-00027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
yata mutants of Drosophila melanogaster exhibit phenotypes including progressive brain shrinkage, developmental abnormalities and shortened lifespan, whereas in mammals, null mutations of the yata ortholog Scyl1 result in motor neuron degeneration. yata mutation also causes defects in the anterograde intracellular trafficking of a subset of proteins including APPL, which is the Drosophila ortholog of mammalian APP, a causative molecule in Alzheimer's disease. SCYL1 binds and regulates the function of coat protein complex I (COPI) in secretory vesicles. Here, we reveal a role for the Drosophila YATA protein in the proper localization of COPI. Immunohistochemical analyses performed using confocal microscopy and structured illumination microscopy showed that YATA colocalizes with COPI and GM130, a cis-Golgi marker. Analyses using transgenically expressed YATA with a modified N-terminal sequence revealed that the N-terminal portion of YATA is required for the proper subcellular localization of YATA. Analysis using transgenically expressed YATA proteins in which the C-terminal sequence was modified revealed a function for the C-terminal portion of YATA in the subcellular localization of COPI. Notably, when YATA was mislocalized, it also caused the mislocalization of COPI, indicating that YATA plays a role in directing COPI to the proper subcellular site. Moreover, when both YATA and COPI were mislocalized, the staining pattern of GM130 revealed Golgi with abnormal elongated shapes. Thus, our in vivo data indicate that YATA plays a role in the proper subcellular localization of COPI.
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Affiliation(s)
- Maiko Saito
- Department of Biomolecular Science, Faculty of Science, Toho University
| | - Minoru Nakayama
- Department of Biomolecular Science, Faculty of Science, Toho University
| | - Kyota Fujita
- Department of Neuropathology, Medical Research Institute, Tokyo Medical and Dental University
| | - Atsuko Uchida
- Department of Neuroscience, The Ohio State University
| | | | - Satoshi Goto
- Department of Life Science, College of Science, Rikkyo University
| | - Hitoshi Okazawa
- Department of Neuropathology, Medical Research Institute, Tokyo Medical and Dental University
| | - Masaki Sone
- Department of Biomolecular Science, Faculty of Science, Toho University
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16
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Aponte-Santiago NA, Littleton JT. Synaptic Properties and Plasticity Mechanisms of Invertebrate Tonic and Phasic Neurons. Front Physiol 2020; 11:611982. [PMID: 33391026 PMCID: PMC7772194 DOI: 10.3389/fphys.2020.611982] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Accepted: 11/24/2020] [Indexed: 12/15/2022] Open
Abstract
Defining neuronal cell types and their associated biophysical and synaptic diversity has become an important goal in neuroscience as a mechanism to create comprehensive brain cell atlases in the post-genomic age. Beyond broad classification such as neurotransmitter expression, interneuron vs. pyramidal, sensory or motor, the field is still in the early stages of understanding closely related cell types. In both vertebrate and invertebrate nervous systems, one well-described distinction related to firing characteristics and synaptic release properties are tonic and phasic neuronal subtypes. In vertebrates, these classes were defined based on sustained firing responses during stimulation (tonic) vs. transient responses that rapidly adapt (phasic). In crustaceans, the distinction expanded to include synaptic release properties, with tonic motoneurons displaying sustained firing and weaker synapses that undergo short-term facilitation to maintain muscle contraction and posture. In contrast, phasic motoneurons with stronger synapses showed rapid depression and were recruited for short bursts during fast locomotion. Tonic and phasic motoneurons with similarities to those in crustaceans have been characterized in Drosophila, allowing the genetic toolkit associated with this model to be used for dissecting the unique properties and plasticity mechanisms for these neuronal subtypes. This review outlines general properties of invertebrate tonic and phasic motoneurons and highlights recent advances that characterize distinct synaptic and plasticity pathways associated with two closely related glutamatergic neuronal cell types that drive invertebrate locomotion.
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Affiliation(s)
- Nicole A. Aponte-Santiago
- The Picower Institute for Learning and Memory, Department of Biology and Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA, United States
- Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, Department of Obstetrics, Gynecology and Reproductive Sciences, University of California, San Francisco, San Francisco, CA, United States
| | - J. Troy Littleton
- The Picower Institute for Learning and Memory, Department of Biology and Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA, United States
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17
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Li TN, Chen YJ, Lu TY, Wang YT, Lin HC, Yao CK. A positive feedback loop between Flower and PI(4,5)P 2 at periactive zones controls bulk endocytosis in Drosophila. eLife 2020; 9:60125. [PMID: 33300871 PMCID: PMC7748424 DOI: 10.7554/elife.60125] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2020] [Accepted: 12/09/2020] [Indexed: 01/01/2023] Open
Abstract
Synaptic vesicle (SV) endocytosis is coupled to exocytosis to maintain SV pool size and thus neurotransmitter release. Intense stimulation induces activity-dependent bulk endocytosis (ADBE) to recapture large quantities of SV constituents in large endosomes from which SVs reform. How these consecutive processes are spatiotemporally coordinated remains unknown. Here, we show that Flower Ca2+ channel-dependent phosphatidylinositol 4,5-bisphosphate (PI(4,5)P2) compartmentalization governs control of these processes in Drosophila. Strong stimuli trigger PI(4,5)P2 microdomain formation at periactive zones. Upon exocytosis, Flower translocates from SVs to periactive zones, where it increases PI(4,5)P2 levels via Ca2+ influxes. Remarkably, PI(4,5)P2 directly enhances Flower channel activity, thereby establishing a positive feedback loop for PI(4,5)P2 microdomain compartmentalization. PI(4,5)P2 microdomains drive ADBE and SV reformation from bulk endosomes. PI(4,5)P2 further retrieves Flower to bulk endosomes, terminating endocytosis. We propose that the interplay between Flower and PI(4,5)P2 is the crucial spatiotemporal cue that couples exocytosis to ADBE and subsequent SV reformation.
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Affiliation(s)
- Tsai-Ning Li
- Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan
| | - Yu-Jung Chen
- Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan
| | - Ting-Yi Lu
- Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan
| | - You-Tung Wang
- Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan
| | - Hsin-Chieh Lin
- Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan
| | - Chi-Kuang Yao
- Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan.,Neuroscience Program of Academia Sinica, Academia Sinica, Taipei, Taiwan.,Institute of Biochemical Sciences, College of Life Science, National Taiwan University, Taipei, Taiwan
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18
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Abstract
Neuropeptides are important for regulating numerous neural functions and behaviors. Release of neuropeptides requires long-lasting, high levels of cytosolic Ca2+ However, the molecular regulation of neuropeptide release remains to be clarified. Recently, Stac3 was identified as a key regulator of L-type Ca2+ channels (CaChs) and excitation-contraction coupling in vertebrate skeletal muscles. There is a small family of stac genes in vertebrates with other members expressed by subsets of neurons in the central nervous system. The function of neural Stac proteins, however, is poorly understood. Drosophila melanogaster contain a single stac gene, Dstac, which is expressed by muscles and a subset of neurons, including neuropeptide-expressing motor neurons. Here, genetic manipulations, coupled with immunolabeling, Ca2+ imaging, electrophysiology, and behavioral analysis, revealed that Dstac regulates L-type CaChs (Dmca1D) in Drosophila motor neurons and this, in turn, controls the release of neuropeptides.
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19
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Martelli F, Zhongyuan Z, Wang J, Wong CO, Karagas NE, Roessner U, Rupasinghe T, Venkatachalam K, Perry T, Bellen HJ, Batterham P. Low doses of the neonicotinoid insecticide imidacloprid induce ROS triggering neurological and metabolic impairments in Drosophila. Proc Natl Acad Sci U S A 2020; 117:25840-25850. [PMID: 32989137 PMCID: PMC7568275 DOI: 10.1073/pnas.2011828117] [Citation(s) in RCA: 62] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Declining insect population sizes are provoking grave concern around the world as insects play essential roles in food production and ecosystems. Environmental contamination by intense insecticide usage is consistently proposed as a significant contributor, among other threats. Many studies have demonstrated impacts of low doses of insecticides on insect behavior, but have not elucidated links to insecticidal activity at the molecular and cellular levels. Here, the histological, physiological, and behavioral impacts of imidacloprid are investigated in Drosophila melanogaster, an experimental organism exposed to insecticides in the field. We show that oxidative stress is a key factor in the mode of action of this insecticide at low doses. Imidacloprid produces an enduring flux of Ca2+ into neurons and a rapid increase in levels of reactive oxygen species (ROS) in the larval brain. It affects mitochondrial function, energy levels, the lipid environment, and transcriptomic profiles. Use of RNAi to induce ROS production in the brain recapitulates insecticide-induced phenotypes in the metabolic tissues, indicating that a signal from neurons is responsible. Chronic low level exposures in adults lead to mitochondrial dysfunction, severe damage to glial cells, and impaired vision. The potent antioxidant, N-acetylcysteine amide (NACA), reduces the severity of a number of the imidacloprid-induced phenotypes, indicating a causal role for oxidative stress. Given that other insecticides are known to generate oxidative stress, this research has wider implications. The systemic impairment of several key biological functions, including vision, reported here would reduce the resilience of insects facing other environmental challenges.
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Affiliation(s)
- Felipe Martelli
- School of BioSciences, The University of Melbourne, Parkville, VIC, 3052, Australia
| | - Zuo Zhongyuan
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030
| | - Julia Wang
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030
| | - Ching-On Wong
- Department of Biological Sciences, Rutgers University, Newark, NJ 07102
| | - Nicholas E Karagas
- Department of Integrative Biology and Pharmacology, McGovern Medical School at the University of Texas Health Sciences Center, Houston, TX 77030
| | - Ute Roessner
- School of BioSciences, The University of Melbourne, Parkville, VIC, 3052, Australia
| | - Thusitha Rupasinghe
- School of BioSciences, The University of Melbourne, Parkville, VIC, 3052, Australia
| | - Kartik Venkatachalam
- Department of Integrative Biology and Pharmacology, McGovern Medical School at the University of Texas Health Sciences Center, Houston, TX 77030
| | - Trent Perry
- School of BioSciences, The University of Melbourne, Parkville, VIC, 3052, Australia
| | - Hugo J Bellen
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030
- Neurological Research Institute, Texas Children's Hospital, Houston, TX 77030
- Howard Hughes Medical Institute, Baylor College of Medicine, Houston, TX 77030
| | - Philip Batterham
- School of BioSciences, The University of Melbourne, Parkville, VIC, 3052, Australia;
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20
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Zhang L, Yu J, Guo X, Wei J, Liu T, Zhang W. Parallel Mechanosensory Pathways Direct Oviposition Decision-Making in Drosophila. Curr Biol 2020; 30:3075-3088.e4. [PMID: 32649914 DOI: 10.1016/j.cub.2020.05.076] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2019] [Revised: 04/09/2020] [Accepted: 05/22/2020] [Indexed: 10/23/2022]
Abstract
Female Drosophila choose their sites for oviposition with deliberation. Female flies employ sensitive chemosensory systems to evaluate chemical cues for egg-laying substrates, but how they determine the physical quality of an oviposition patch remains largely unexplored. Here we report that flies evaluate the stiffness of the substrate surface using sensory structures on their appendages. The TRPV family channel Nanchung is required for the detection of all stiffness ranges tested, whereas two other proteins, Inactive and DmPiezo, interact with Nanchung to sense certain spectral ranges of substrate stiffness differences. Furthermore, Tmc is critical for sensing subtle differences in substrate stiffness. The Tmc channel is expressed in distinct patterns on the labellum and legs and the mechanosensory inputs coordinate to direct the final decision making for egg laying. Our study thus reveals the machinery for deliberate egg-laying decision making in fruit flies to ensure optimal survival for their offspring.
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Affiliation(s)
- Liwei Zhang
- School of Life Sciences, Tsinghua-Peking Joint Center for Life Sciences, IDG/McGovern Institute for Brain Research at Tsinghua, Tsinghua University, Beijing 100084, China.
| | - Jie Yu
- School of Life Sciences, Tsinghua-Peking Joint Center for Life Sciences, IDG/McGovern Institute for Brain Research at Tsinghua, Tsinghua University, Beijing 100084, China
| | - Xuan Guo
- School of Life Sciences, Tsinghua-Peking Joint Center for Life Sciences, IDG/McGovern Institute for Brain Research at Tsinghua, Tsinghua University, Beijing 100084, China
| | - Jianhuan Wei
- School of Life Sciences, Tsinghua-Peking Joint Center for Life Sciences, IDG/McGovern Institute for Brain Research at Tsinghua, Tsinghua University, Beijing 100084, China
| | - Ting Liu
- School of Life Sciences, Tsinghua-Peking Joint Center for Life Sciences, IDG/McGovern Institute for Brain Research at Tsinghua, Tsinghua University, Beijing 100084, China
| | - Wei Zhang
- School of Life Sciences, Tsinghua-Peking Joint Center for Life Sciences, IDG/McGovern Institute for Brain Research at Tsinghua, Tsinghua University, Beijing 100084, China.
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21
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TRPV4 disrupts mitochondrial transport and causes axonal degeneration via a CaMKII-dependent elevation of intracellular Ca 2. Nat Commun 2020; 11:2679. [PMID: 32471994 PMCID: PMC7260201 DOI: 10.1038/s41467-020-16411-5] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2019] [Accepted: 05/01/2020] [Indexed: 12/14/2022] Open
Abstract
The cation channel transient receptor potential vanilloid 4 (TRPV4) is one of the few identified ion channels that can directly cause inherited neurodegeneration syndromes, but the molecular mechanisms are unknown. Here, we show that in vivo expression of a neuropathy-causing TRPV4 mutant (TRPV4R269C) causes dose-dependent neuronal dysfunction and axonal degeneration, which are rescued by genetic or pharmacological blockade of TRPV4 channel activity. TRPV4R269C triggers increased intracellular Ca2+ through a Ca2+/calmodulin-dependent protein kinase II (CaMKII)-mediated mechanism, and CaMKII inhibition prevents both increased intracellular Ca2+ and neurotoxicity in Drosophila and cultured primary mouse neurons. Importantly, TRPV4 activity impairs axonal mitochondrial transport, and TRPV4-mediated neurotoxicity is modulated by the Ca2+-binding mitochondrial GTPase Miro. Our data highlight an integral role for CaMKII in neuronal TRPV4-associated Ca2+ responses, the importance of tightly regulated Ca2+ dynamics for mitochondrial axonal transport, and the therapeutic promise of TRPV4 antagonists for patients with TRPV4-related neurodegenerative diseases. Mutations in the TRPV4 channel cause inherited neurodegeneration syndromes, but the molecular mechanisms are unknown. Here the authors reveal that TRPV4 activation causes dose-dependent, CaMKII-mediated neuronal dysfunction and axonal degeneration via disruption of mitochondrial axonal transport.
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22
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Sex specific effects of capsaicin on longevity regulation. Exp Gerontol 2020; 130:110788. [DOI: 10.1016/j.exger.2019.110788] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2019] [Revised: 11/15/2019] [Accepted: 11/20/2019] [Indexed: 01/26/2023]
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Role of the TRPV Channels in the Endoplasmic Reticulum Calcium Homeostasis. Cells 2020; 9:cells9020317. [PMID: 32013022 PMCID: PMC7072170 DOI: 10.3390/cells9020317] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2019] [Revised: 01/08/2020] [Accepted: 01/21/2020] [Indexed: 01/01/2023] Open
Abstract
It has been widely established that transient receptor potential vanilloid (TRPV) channels play a crucial role in calcium homeostasis in mammalian cells. Modulation of TRPV channels activity can modify their physiological function leading to some diseases and disorders like neurodegeneration, pain, cancer, skin disorders, etc. It should be noted that, despite TRPV channels importance, our knowledge of the TRPV channels functions in cells is mostly limited to their plasma membrane location. However, some TRPV channels were shown to be expressed in the endoplasmic reticulum where their modulation by activators and/or inhibitors was demonstrated to be crucial for intracellular signaling. In this review, we have intended to summarize the poorly studied roles and functions of these channels in the endoplasmic reticulum.
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Zhu J, Liu X, Zhu K, Zhou H, Li L, Li Z, Qin W, He Y. Knockdown of TRPV Genes Affects the Locomotion and Feeding Behavior of Nilaparvata lugens (Hemiptera: Delphacidae). JOURNAL OF INSECT SCIENCE (ONLINE) 2020; 20:5736529. [PMID: 32061084 PMCID: PMC7022682 DOI: 10.1093/jisesa/ieaa002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/08/2019] [Indexed: 06/10/2023]
Abstract
The vanilloid-type transient receptor potential (TRPV) channel is reported to be the molecular target of the commercial insecticide pymetrozine, which specifically disrupts the feeding of plant sap-sucking insects. However, the functions of TRPV channels in plant sap-sucking insects have not been fully elucidated. In the present study, RNA interference was used to investigate the effects of the knockdown of TRPV genes (Nan and Iav) on the mortality, locomotion, and feeding behavior of an important plant-feeding insect pest in rice, the brown planthopper, Nilaparvata lugens. Injecting dsRNA of Nan and Iav into fourth-instar nymphs significantly knocked down the target genes. The injection of dsNan or dsIav did not affect any morphological phenotype (including leg extension) of N. lugens nymphs and adults. Knockdown of Nan or Iav resulted in significantly decreased climbing activity against top plants but did not influence the leg-griping strength of adults. Knockdown of Nan resulted in a significantly elevated mortality of N. lugens in the observation period of 7 d after injection, whereas no significant difference in survival rates 7 d after injection was found between dsIav-injected and dsGFP-injected insects. Electropenetrographic (EPG) recordings indicated that knockdown of Nan and Iav reduced the ingestion activity in the rice phloem tissues of N. lugens. Knockdown of Nan and Iav significantly reduced the amount of honeydew excreted by N. lugens. Our findings indicated a relationship between TRPV and N. lugens locomotion and feeding behavior, which may help to fully elucidate the functions of TRPV in insects.
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Affiliation(s)
- Jinghua Zhu
- Hubei Insect Resources Utilization and Sustainable Pest Management Key Laboratory, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Xiaoqing Liu
- Hubei Insect Resources Utilization and Sustainable Pest Management Key Laboratory, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Kunmiao Zhu
- Hubei Insect Resources Utilization and Sustainable Pest Management Key Laboratory, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Hanyu Zhou
- Hubei Insect Resources Utilization and Sustainable Pest Management Key Laboratory, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Liang Li
- Hubei Insect Resources Utilization and Sustainable Pest Management Key Laboratory, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Zengxin Li
- Hubei Insect Resources Utilization and Sustainable Pest Management Key Laboratory, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Weiwei Qin
- Hubei Insect Resources Utilization and Sustainable Pest Management Key Laboratory, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Yueping He
- Hubei Insect Resources Utilization and Sustainable Pest Management Key Laboratory, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, China
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Connolly KJ, O'Hare MB, Mohammed A, Aitchison KM, Anthoney NC, Taylor MJ, Stewart BA, Tuxworth RI, Tear G. The neuronal ceroid lipofuscinosis protein Cln7 functions in the postsynaptic cell to regulate synapse development. Sci Rep 2019; 9:15592. [PMID: 31666534 PMCID: PMC6821864 DOI: 10.1038/s41598-019-51588-w] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2019] [Accepted: 10/03/2019] [Indexed: 02/08/2023] Open
Abstract
The neuronal ceroid lipofuscinoses (NCLs) are a group of fatal, monogenic neurodegenerative disorders with an early onset in infancy or childhood. Despite identification of the genes disrupted in each form of the disease, their normal cellular role and how their deficits lead to disease pathology is not fully understood. Cln7, a major facilitator superfamily domain-containing protein, is affected in a late infantile-onset form of NCL. Cln7 is conserved across species suggesting a common function. Here we demonstrate that Cln7 is required for the normal growth of synapses at the Drosophila larval neuromuscular junction. In a Cln7 mutant, synapses fail to develop fully leading to reduced function and behavioral changes with dysregulation of TOR activity. Cln7 expression is restricted to the post-synaptic cell and the protein localizes to vesicles immediately adjacent to the post-synaptic membrane. Our data suggest an involvement for Cln7 in regulating trans-synaptic communication necessary for normal synapse development.
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Affiliation(s)
- Kyle J Connolly
- Institute of Cancer and Genomic Sciences, University of Birmingham, Birmingham, B15 2TT, UK
| | - Megan B O'Hare
- Department of Developmental Neurobiology, King's College London, New Hunt's House, London, SE1 1UL, UK
| | - Alamin Mohammed
- Institute of Cancer and Genomic Sciences, University of Birmingham, Birmingham, B15 2TT, UK
| | - Katelyn M Aitchison
- Institute of Cancer and Genomic Sciences, University of Birmingham, Birmingham, B15 2TT, UK
| | - Niki C Anthoney
- Institute of Cancer and Genomic Sciences, University of Birmingham, Birmingham, B15 2TT, UK
| | - Matthew J Taylor
- Institute of Cancer and Genomic Sciences, University of Birmingham, Birmingham, B15 2TT, UK
| | - Bryan A Stewart
- Department of Biology, University of Toronto Mississauga, Mississauga, ON, L5L 1C6, Canada.,Department of Cell and Systems Biology, University of Toronto, Toronto, ON, M5S 3G5, Canada
| | - Richard I Tuxworth
- Institute of Cancer and Genomic Sciences, University of Birmingham, Birmingham, B15 2TT, UK.
| | - Guy Tear
- Department of Developmental Neurobiology, King's College London, New Hunt's House, London, SE1 1UL, UK.
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26
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Roles for the Endoplasmic Reticulum in Regulation of Neuronal Calcium Homeostasis. Cells 2019; 8:cells8101232. [PMID: 31658749 PMCID: PMC6829861 DOI: 10.3390/cells8101232] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2019] [Revised: 10/01/2019] [Accepted: 10/03/2019] [Indexed: 02/06/2023] Open
Abstract
By influencing Ca2+ homeostasis in spatially and architecturally distinct neuronal compartments, the endoplasmic reticulum (ER) illustrates the notion that form and function are intimately related. The contribution of ER to neuronal Ca2+ homeostasis is attributed to the organelle being the largest reservoir of intracellular Ca2+ and having a high density of Ca2+ channels and transporters. As such, ER Ca2+ has incontrovertible roles in the regulation of axodendritic growth and morphology, synaptic vesicle release, and neural activity dependent gene expression, synaptic plasticity, and mitochondrial bioenergetics. Not surprisingly, many neurological diseases arise from ER Ca2+ dyshomeostasis, either directly due to alterations in ER resident proteins, or indirectly via processes that are coupled to the regulators of ER Ca2+ dynamics. In this review, we describe the mechanisms involved in the establishment of ER Ca2+ homeostasis in neurons. We elaborate upon how changes in the spatiotemporal dynamics of Ca2+ exchange between the ER and other organelles sculpt neuronal function and provide examples that demonstrate the involvement of ER Ca2+ dyshomeostasis in a range of neurological and neurodegenerative diseases.
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27
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Huang H, Liu S, Kornberg TB. Glutamate signaling at cytoneme synapses. Science 2019; 363:948-955. [PMID: 30819957 DOI: 10.1126/science.aat5053] [Citation(s) in RCA: 46] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2018] [Revised: 05/14/2018] [Accepted: 02/04/2019] [Indexed: 12/24/2022]
Abstract
We investigated the roles of components of neuronal synapses for development of the Drosophila air sac primordium (ASP). The ASP, an epithelial tube, extends specialized signaling filopodia called cytonemes that take up signals such as Dpp (Decapentaplegic, a homolog of the vertebrate bone morphogenetic protein) from the wing imaginal disc. Dpp signaling in the ASP was compromised if disc cells lacked Synaptobrevin and Synaptotagmin-1 (which function in vesicle transport at neuronal synapses), the glutamate transporter, and a voltage-gated calcium channel, or if ASP cells lacked Synaptotagmin-4 or the glutamate receptor GluRII. Transient elevations of intracellular calcium in ASP cytonemes correlate with signaling activity. Calcium transients in ASP cells depend on GluRII, are activated by l-glutamate and by stimulation of an optogenetic ion channel expressed in the wing disc, and are inhibited by EGTA and by the GluR inhibitor NASPM (1-naphthylacetyl spermine trihydrochloride). Activation of GluRII is essential but not sufficient for signaling. Cytoneme-mediated signaling is glutamatergic.
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Affiliation(s)
- Hai Huang
- Cardiovascular Research Institute, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Songmei Liu
- Cardiovascular Research Institute, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Thomas B Kornberg
- Cardiovascular Research Institute, University of California, San Francisco, San Francisco, CA 94143, USA.
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28
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Ojelade SA, Lee TV, Giagtzoglou N, Yu L, Ugur B, Li Y, Duraine L, Zuo Z, Petyuk V, De Jager PL, Bennett DA, Arenkiel BR, Bellen HJ, Shulman JM. cindr, the Drosophila Homolog of the CD2AP Alzheimer's Disease Risk Gene, Is Required for Synaptic Transmission and Proteostasis. Cell Rep 2019; 28:1799-1813.e5. [PMID: 31412248 PMCID: PMC6703184 DOI: 10.1016/j.celrep.2019.07.041] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2018] [Revised: 05/30/2019] [Accepted: 07/15/2019] [Indexed: 12/11/2022] Open
Abstract
The Alzheimer's disease (AD) susceptibility gene, CD2-associated protein (CD2AP), encodes an actin binding adaptor protein, but its function in the nervous system is largely unknown. Loss of the Drosophila ortholog cindr enhances neurotoxicity of human Tau, which forms neurofibrillary tangle pathology in AD. We show that Cindr is expressed in neurons and present at synaptic terminals. cindr mutants show impairments in synapse maturation and both synaptic vesicle recycling and release. Cindr associates and genetically interacts with 14-3-3ζ, regulates the ubiquitin-proteasome system, and affects turnover of Synapsin and the plasma membrane calcium ATPase (PMCA). Loss of cindr elevates PMCA levels and reduces cytosolic calcium. Studies of Cd2ap null mice support a conserved role in synaptic proteostasis, and CD2AP protein levels are inversely related to Synapsin abundance in human postmortem brains. Our results reveal CD2AP neuronal requirements with relevance to AD susceptibility, including for proteostasis, calcium handling, and synaptic structure and function.
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Affiliation(s)
- Shamsideen A Ojelade
- Department of Neurology, Baylor College of Medicine, Houston, TX 77030, USA; Jan and Dan Duncan Neurologic Research Institute, Texas Children's Hospital, Houston, TX 77030, USA
| | - Tom V Lee
- Department of Neurology, Baylor College of Medicine, Houston, TX 77030, USA; Jan and Dan Duncan Neurologic Research Institute, Texas Children's Hospital, Houston, TX 77030, USA
| | - Nikolaos Giagtzoglou
- Department of Neurology, Baylor College of Medicine, Houston, TX 77030, USA; Jan and Dan Duncan Neurologic Research Institute, Texas Children's Hospital, Houston, TX 77030, USA
| | - Lei Yu
- Rush Alzheimer's Disease Center, Rush University Medical Center, Chicago, IL 60612, USA
| | - Berrak Ugur
- Program in Developmental Biology, Baylor College of Medicine, Houston, TX 77030, USA
| | - Yarong Li
- Department of Neurology, Baylor College of Medicine, Houston, TX 77030, USA; Jan and Dan Duncan Neurologic Research Institute, Texas Children's Hospital, Houston, TX 77030, USA
| | - Lita Duraine
- Department of Molecular & Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Zhongyuan Zuo
- Department of Molecular & Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Vlad Petyuk
- Pacific Northwest National Laboratory, Richland, WA 99354, USA
| | - Philip L De Jager
- Center for Translational & Computational Neuroimmunology, Department of Neurology and the Taub Institute, Columbia University Medical Center, New York, NY 10032, USA; Cell Circuits Program, Broad Institute, Cambridge, MA 02142, USA
| | - David A Bennett
- Rush Alzheimer's Disease Center, Rush University Medical Center, Chicago, IL 60612, USA
| | - Benjamin R Arenkiel
- Jan and Dan Duncan Neurologic Research Institute, Texas Children's Hospital, Houston, TX 77030, USA; Program in Developmental Biology, Baylor College of Medicine, Houston, TX 77030, USA; Department of Molecular & Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Department of Neuroscience, Baylor College of Medicine, Houston, TX 77030, USA
| | - Hugo J Bellen
- Jan and Dan Duncan Neurologic Research Institute, Texas Children's Hospital, Houston, TX 77030, USA; Program in Developmental Biology, Baylor College of Medicine, Houston, TX 77030, USA; Department of Molecular & Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Department of Neuroscience, Baylor College of Medicine, Houston, TX 77030, USA; Howard Hughes Medical Institute, Baylor College of Medicine, Houston, TX 77030, USA
| | - Joshua M Shulman
- Department of Neurology, Baylor College of Medicine, Houston, TX 77030, USA; Jan and Dan Duncan Neurologic Research Institute, Texas Children's Hospital, Houston, TX 77030, USA; Program in Developmental Biology, Baylor College of Medicine, Houston, TX 77030, USA; Department of Molecular & Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Department of Neuroscience, Baylor College of Medicine, Houston, TX 77030, USA.
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29
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James TD, Zwiefelhofer DJ, Frank CA. Maintenance of homeostatic plasticity at the Drosophila neuromuscular synapse requires continuous IP 3-directed signaling. eLife 2019; 8:39643. [PMID: 31180325 PMCID: PMC6557630 DOI: 10.7554/elife.39643] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2018] [Accepted: 05/27/2019] [Indexed: 12/18/2022] Open
Abstract
Synapses and circuits rely on neuroplasticity to adjust output and meet physiological needs. Forms of homeostatic synaptic plasticity impart stability at synapses by countering destabilizing perturbations. The Drosophila melanogaster larval neuromuscular junction (NMJ) is a model synapse with robust expression of homeostatic plasticity. At the NMJ, a homeostatic system detects impaired postsynaptic sensitivity to neurotransmitter and activates a retrograde signal that restores synaptic function by adjusting neurotransmitter release. This process has been separated into temporally distinct phases, induction and maintenance. One prevailing hypothesis is that a shared mechanism governs both phases. Here, we show the two phases are separable. Combining genetics, pharmacology, and electrophysiology, we find that a signaling system consisting of PLCβ, inositol triphosphate (IP3), IP3 receptors, and Ryanodine receptors is required only for the maintenance of homeostatic plasticity. We also find that the NMJ is capable of inducing homeostatic signaling even when its sustained maintenance process is absent. Editorial note: This article has been through an editorial process in which the authors decide how to respond to the issues raised during peer review. The Reviewing Editor's assessment is that all the issues have been addressed (see decision letter).
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Affiliation(s)
- Thomas D James
- Department of Anatomy and Cell Biology, University of Iowa Carver College of Medicine, Iowa City, United States.,Interdisciplinary Graduate Program in Neuroscience, University of Iowa, Iowa City, United States
| | - Danielle J Zwiefelhofer
- Department of Anatomy and Cell Biology, University of Iowa Carver College of Medicine, Iowa City, United States
| | - C Andrew Frank
- Department of Anatomy and Cell Biology, University of Iowa Carver College of Medicine, Iowa City, United States.,Interdisciplinary Programs in Neuroscience, Genetics and Molecular Medicine, University of Iowa, Iowa City, United States
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30
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Mao F, Guo L, Jin M, Qiao XM, Ye GY, Huang J. Molecular cloning and characterization of TRPVs in two rice pests: Nilaparvata lugens (Stål) and Nephotettix cincticeps (Uhler). PEST MANAGEMENT SCIENCE 2019; 75:1361-1369. [PMID: 30370997 DOI: 10.1002/ps.5254] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2018] [Revised: 09/28/2018] [Accepted: 10/26/2018] [Indexed: 06/08/2023]
Abstract
BACKGROUD Insect TRPV is a subfamily of transient receptor potential (TRP) ion channels, including two genes, nanchung and inactive. It has recently been found that two commercial insecticides, pymetrozine and pyrifluquinazon, target the heteromeric TRPV ion channel complex which is specifically expressed in the chordotonal organ neurons in Drosophila. However, information on the TRPV genes in agricultural insects is still limited. RESULTS In this study, we cloned and characterized two TRPV genes from Nilaparvata lugens (NlNan and NLIav) and Nephotettix cincticeps (NcNan and NcIav), two serious rice pests throughout Asia. The deduced amino acid sequences share highly identity with other insect homologues (58-85%) and have the characteristic TRPV domain architecture: five ankyrin repeats and six transmembrane domains. These TRPV transcripts were expressed in all developmental stages and expression levels in male adults were significantly higher than in female adults. Moreover, expression levels in antennae were much higher than in heads and legs. CONCLUSION NlNan, NlIav, NcNan and NcIav may have roles in male-specific behaviors, and the sequence information lays the foundation for further study on the structural and functional characterization of TRPVs in agricultural pests. © 2018 Society of Chemical Industry.
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Affiliation(s)
- Fen Mao
- State Key Laboratory of Rice Biology & Ministry of Agriculture Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Institute of Insect Sciences, Zhejiang University, Hangzhou, China
| | - Lei Guo
- State Key Laboratory of Rice Biology & Ministry of Agriculture Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Institute of Insect Sciences, Zhejiang University, Hangzhou, China
| | - Miao Jin
- State Key Laboratory of Rice Biology & Ministry of Agriculture Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Institute of Insect Sciences, Zhejiang University, Hangzhou, China
| | - Xiao-Mu Qiao
- State Key Laboratory of Rice Biology & Ministry of Agriculture Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Institute of Insect Sciences, Zhejiang University, Hangzhou, China
| | - Gong-Yin Ye
- State Key Laboratory of Rice Biology & Ministry of Agriculture Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Institute of Insect Sciences, Zhejiang University, Hangzhou, China
| | - Jia Huang
- State Key Laboratory of Rice Biology & Ministry of Agriculture Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Institute of Insect Sciences, Zhejiang University, Hangzhou, China
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31
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Rodrigues AZC, Wang ZM, Messi ML, Delbono O. Sympathomimetics regulate neuromuscular junction transmission through TRPV1, P/Q- and N-type Ca 2+ channels. Mol Cell Neurosci 2019; 95:59-70. [PMID: 30763691 PMCID: PMC6394868 DOI: 10.1016/j.mcn.2019.01.007] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2018] [Revised: 01/24/2019] [Accepted: 01/26/2019] [Indexed: 01/10/2023] Open
Abstract
Increasing evidence indicates that, first, the sympathetic nervous system interacts extensively with both vasculature and skeletal muscle fibers near neuromuscular junctions (NMJs) and, second, its neurotransmitter, noradrenaline, influences myofiber molecular composition and function and motor innervation. Since sympathomimetic agents have been reported to improve NMJ transmission, we examined whether two in clinical use, salbutamol and clenbuterol, affect the motor axon terminal via extracellular Ca2+ and molecular targets, such as TRPV1 and P/Q- and N-type voltage-activated Ca2+ channels. Electrophysiological recordings in ex-vivo preparations of peroneal nerves and lumbricalis muscles from young adult mice focused on spontaneous miniature end-plate potentials and singly and repetitively evoked end-plate potentials. Adding one dose of salbutamol or clenbuterol to the nerve/muscle preparation or repeatedly administering salbutamol to a mouse for 4 weeks increased spontaneous and evoked synaptic vesicle release but induced a steep decline in EPP amplitude in response to repetitive nerve stimulation. These effects were mediated primarily by ω-agatoxin IVA-sensitive P/Q-type and secondarily by ω-conotoxin GVIA-sensitive N-type Ca2+ channels. Presynaptic arvanil-sensitive TRPV1 channels seem to regulate Ca2+ at the motor neuron terminal at rest, while putative presynaptic β-adrenergic receptors may mediate sympathomimetic and catecholamine effects on presynaptic Ca2+ channels during NMJ activation.
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Affiliation(s)
- Anna Zaia Carolina Rodrigues
- Department of Internal Medicine, Section on Gerontology and Geriatric Medicine, Wake Forest School of Medicine, Winston-Salem, NC, United States of America; Neuroscience Program, Wake Forest School of Medicine, Winston-Salem, NC, United States of America
| | - Zhong-Min Wang
- Department of Internal Medicine, Section on Gerontology and Geriatric Medicine, Wake Forest School of Medicine, Winston-Salem, NC, United States of America
| | - María Laura Messi
- Department of Internal Medicine, Section on Gerontology and Geriatric Medicine, Wake Forest School of Medicine, Winston-Salem, NC, United States of America
| | - Osvaldo Delbono
- Department of Internal Medicine, Section on Gerontology and Geriatric Medicine, Wake Forest School of Medicine, Winston-Salem, NC, United States of America; Neuroscience Program, Wake Forest School of Medicine, Winston-Salem, NC, United States of America.
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32
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Brusich DJ, Spring AM, James TD, Yeates CJ, Helms TH, Frank CA. Drosophila CaV2 channels harboring human migraine mutations cause synapse hyperexcitability that can be suppressed by inhibition of a Ca2+ store release pathway. PLoS Genet 2018; 14:e1007577. [PMID: 30080864 PMCID: PMC6095605 DOI: 10.1371/journal.pgen.1007577] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2017] [Revised: 08/16/2018] [Accepted: 07/20/2018] [Indexed: 11/28/2022] Open
Abstract
Gain-of-function mutations in the human CaV2.1 gene CACNA1A cause familial hemiplegic migraine type 1 (FHM1). To characterize cellular problems potentially triggered by CaV2.1 gains of function, we engineered mutations encoding FHM1 amino-acid substitutions S218L (SL) and R192Q (RQ) into transgenes of Drosophila melanogaster CaV2/cacophony. We expressed the transgenes pan-neuronally. Phenotypes were mild for RQ-expressing animals. By contrast, single mutant SL- and complex allele RQ,SL-expressing animals showed overt phenotypes, including sharply decreased viability. By electrophysiology, SL- and RQ,SL-expressing neuromuscular junctions (NMJs) exhibited enhanced evoked discharges, supernumerary discharges, and an increase in the amplitudes and frequencies of spontaneous events. Some spontaneous events were gigantic (10-40 mV), multi-quantal events. Gigantic spontaneous events were eliminated by application of TTX-or by lowered or chelated Ca2+-suggesting that gigantic events were elicited by spontaneous nerve firing. A follow-up genetic approach revealed that some neuronal hyperexcitability phenotypes were reversed after knockdown or mutation of Drosophila homologs of phospholipase Cβ (PLCβ), IP3 receptor, or ryanodine receptor (RyR)-all factors known to mediate Ca2+ release from intracellular stores. Pharmacological inhibitors of intracellular Ca2+ store release produced similar effects. Interestingly, however, the decreased viability phenotype was not reversed by genetic impairment of intracellular Ca2+ release factors. On a cellular level, our data suggest inhibition of signaling that triggers intracellular Ca2+ release could counteract hyperexcitability induced by gains of CaV2.1 function.
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Affiliation(s)
- Douglas J. Brusich
- Department of Anatomy and Cell Biology, University of Iowa Carver College of Medicine, Iowa City, IA, United States of America
| | - Ashlyn M. Spring
- Department of Anatomy and Cell Biology, University of Iowa Carver College of Medicine, Iowa City, IA, United States of America
- Interdisciplinary Graduate Program in Genetics, University of Iowa, Iowa City, IA, United States of America
| | - Thomas D. James
- Department of Anatomy and Cell Biology, University of Iowa Carver College of Medicine, Iowa City, IA, United States of America
- Interdisciplinary Graduate Program in Neuroscience, University of Iowa, Iowa City, IA, United States of America
| | - Catherine J. Yeates
- Department of Anatomy and Cell Biology, University of Iowa Carver College of Medicine, Iowa City, IA, United States of America
- Interdisciplinary Graduate Program in Neuroscience, University of Iowa, Iowa City, IA, United States of America
| | - Timothy H. Helms
- Department of Anatomy and Cell Biology, University of Iowa Carver College of Medicine, Iowa City, IA, United States of America
| | - C. Andrew Frank
- Department of Anatomy and Cell Biology, University of Iowa Carver College of Medicine, Iowa City, IA, United States of America
- Interdisciplinary Graduate Program in Genetics, University of Iowa, Iowa City, IA, United States of America
- Interdisciplinary Graduate Program in Neuroscience, University of Iowa, Iowa City, IA, United States of America
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33
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Wang Q, Han TH, Nguyen P, Jarnik M, Serpe M. Tenectin recruits integrin to stabilize bouton architecture and regulate vesicle release at the Drosophila neuromuscular junction. eLife 2018; 7:35518. [PMID: 29901439 PMCID: PMC6040883 DOI: 10.7554/elife.35518] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2018] [Accepted: 06/13/2018] [Indexed: 11/15/2022] Open
Abstract
Assembly, maintenance and function of synaptic junctions depend on extracellular matrix (ECM) proteins and their receptors. Here we report that Tenectin (Tnc), a Mucin-type protein with RGD motifs, is an ECM component required for the structural and functional integrity of synaptic specializations at the neuromuscular junction (NMJ) in Drosophila. Using genetics, biochemistry, electrophysiology, histology and electron microscopy, we show that Tnc is secreted from motor neurons and striated muscles and accumulates in the synaptic cleft. Tnc selectively recruits αPS2/βPS integrin at synaptic terminals, but only the cis Tnc/integrin complexes appear to be biologically active. These complexes have distinct pre- and postsynaptic functions, mediated at least in part through the local engagement of the spectrin-based membrane skeleton: the presynaptic complexes control neurotransmitter release, while postsynaptic complexes ensure the size and architectural integrity of synaptic boutons. Our study reveals an unprecedented role for integrin in the synaptic recruitment of spectrin-based membrane skeleton. Nerve cells or neurons can communicate with each other by releasing chemical messengers into the gap between them, the synapse. Both neurons and synapses are surrounded by a network of proteins called the extracellular matrix, which anchors, protects and supports the synapse. The matrix also helps to regulate the dynamic communication across the synapses and consequently neurons. Little is known about the proteins of the extracellular matrix, in particular about the ones involved in structural support. This is especially important for the so-called neuromuscular junctions, where neurons stimulate muscle contraction and trigger vigorous movement. Receptor proteins on cell surfaces, such as integrins, can bind to the extracellular matrix proteins to anchor the cells and are important for all cell junctions, including synaptic junctions. But because of their many essential roles during development, it was unclear how integrins modulate the activity of the synapse. To investigate this further, Wang et al. studied the neuromuscular junctions of fruit flies. The experiments revealed that both muscle and neurons secrete a large protein called Tenectin, which accumulates into the small space between the neuron and the muscle, the synaptic cleft. This protein can bind to integrin and is necessary to support the neuromuscular junction structurally and functionally. Wang et al. discovered that Tenectin works by gathering integrins on the surface of the neuron and the muscle. In the neuron, Tenectin forms complexes with integrin to regulate the release of neurotransmitters. In the muscle, the complexes provide support to the synaptic structures. However, when Tenectin was experimentally removed, it only disrupted the integrins at the neuromuscular junction, without affecting integrins in other regions of the cells, such as the site where the muscle uses integrins to attach to the tendon. Moreover, without Tenectin an important intracellular scaffolding meshwork that lines up and reinforces cell membranes was no longer organized properly at the synapse. A next step will be to identify the missing components between Tenectin/integrin complexes on the surface of neurons and the neurotransmitter release machinery inside the cells. The extracellular matrix and its receptors play fundamental roles in the development and function of the nervous system. A better knowledge of the underlying mechanisms will help us to better understand the complex interplay between the synapse and the extracellular matrix.
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Affiliation(s)
- Qi Wang
- Section on Cellular Communication, Eunice Kennedy Shriver, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, United States
| | - Tae Hee Han
- Section on Cellular Communication, Eunice Kennedy Shriver, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, United States
| | - Peter Nguyen
- Section on Cellular Communication, Eunice Kennedy Shriver, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, United States
| | - Michal Jarnik
- Section on Intracellular Protein Trafficking, Eunice Kennedy Shriver, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, United States
| | - Mihaela Serpe
- Section on Cellular Communication, Eunice Kennedy Shriver, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, United States
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34
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Extended Synaptotagmin Localizes to Presynaptic ER and Promotes Neurotransmission and Synaptic Growth in Drosophila. Genetics 2017; 207:993-1006. [PMID: 28882990 DOI: 10.1534/genetics.117.300261] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2017] [Accepted: 09/01/2017] [Indexed: 01/08/2023] Open
Abstract
The endoplasmic reticulum (ER) is an extensive organelle in neurons with important roles at synapses including the regulation of cytosolic Ca2+, neurotransmission, lipid metabolism, and membrane trafficking. Despite intriguing evidence for these crucial functions, how the presynaptic ER influences synaptic physiology remains enigmatic. To gain insight into this question, we have generated and characterized mutations in the single extended synaptotagmin (Esyt) ortholog in Drosophila melanogaster Esyts are evolutionarily conserved ER proteins with Ca2+-sensing domains that have recently been shown to orchestrate membrane tethering and lipid exchange between the ER and plasma membrane. We first demonstrate that Esyt localizes to presynaptic ER structures at the neuromuscular junction. Next, we show that synaptic growth, structure, and homeostatic plasticity are surprisingly unperturbed at synapses lacking Esyt expression. However, neurotransmission is reduced in Esyt mutants, consistent with a presynaptic role in promoting neurotransmitter release. Finally, neuronal overexpression of Esyt enhances synaptic growth and the sustainment of the vesicle pool during intense activity, suggesting that increased Esyt levels may modulate the membrane trafficking and/or resting Ca2+ pathways that control synapse extension. Thus, we identify Esyt as a presynaptic ER protein that can promote neurotransmission and synaptic growth, revealing the first in vivo neuronal functions of this conserved gene family.
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35
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Xu C, Luo J, He L, Montell C, Perrimon N. Oxidative stress induces stem cell proliferation via TRPA1/RyR-mediated Ca 2+ signaling in the Drosophila midgut. eLife 2017; 6. [PMID: 28561738 PMCID: PMC5451214 DOI: 10.7554/elife.22441] [Citation(s) in RCA: 57] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2016] [Accepted: 05/23/2017] [Indexed: 12/20/2022] Open
Abstract
Precise regulation of stem cell activity is crucial for tissue homeostasis and necessary to prevent overproliferation. In the Drosophila adult gut, high levels of reactive oxygen species (ROS) has been detected with different types of tissue damage, and oxidative stress has been shown to be both necessary and sufficient to trigger intestinal stem cell (ISC) proliferation. However, the connection between oxidative stress and mitogenic signals remains obscure. In a screen for genes required for ISC proliferation in response to oxidative stress, we identified two regulators of cytosolic Ca2+ levels, transient receptor potential A1 (TRPA1) and ryanodine receptor (RyR). Characterization of TRPA1 and RyR demonstrates that Ca2+ signaling is required for oxidative stress-induced activation of the Ras/MAPK pathway, which in turns drives ISC proliferation. Our findings provide a link between redox regulation and Ca2+ signaling and reveal a novel mechanism by which ISCs detect stress signals.
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Affiliation(s)
- Chiwei Xu
- Department of Genetics, Harvard Medical School, Boston, United States
| | - Junjie Luo
- Department of Molecular, Cellular and Developmental Biology, University of California Santa Barbara, Santa Barbara, United States.,Neuroscience Research Institute, University of California, Santa Barbara, Santa Barbara, United States
| | - Li He
- Department of Genetics, Harvard Medical School, Boston, United States
| | - Craig Montell
- Department of Molecular, Cellular and Developmental Biology, University of California Santa Barbara, Santa Barbara, United States.,Neuroscience Research Institute, University of California, Santa Barbara, Santa Barbara, United States
| | - Norbert Perrimon
- Department of Genetics, Harvard Medical School, Boston, United States.,Howard Hughes Medical Institute, Harvard Medical School, Boston, United States
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In Vivo Calcium Signaling during Synaptic Refinement at the Drosophila Neuromuscular Junction. J Neurosci 2017; 37:5511-5526. [PMID: 28476946 DOI: 10.1523/jneurosci.2922-16.2017] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2016] [Revised: 04/17/2017] [Accepted: 04/18/2017] [Indexed: 11/21/2022] Open
Abstract
Neural activity plays a key role in pruning aberrant synapses in various neural systems, including the mammalian cortex, where low-frequency (0.01 Hz) calcium oscillations refine topographic maps. However, the activity-dependent molecular mechanisms remain incompletely understood. Activity-dependent pruning also occurs at embryonic Drosophila neuromuscular junctions (NMJs), where low-frequency Ca2+ oscillations are required for synaptic refinement and the response to the muscle-derived chemorepellant Sema2a. We examined embryonic growth cone filopodia in vivo to directly observe their exploration and to analyze the episodic Ca2+ oscillations involved in refinement. Motoneuron filopodia repeatedly contacted off-target muscle fibers over several hours during late embryogenesis, with episodic Ca2+ signals present in both motile filopodia as well as in later-stabilized synaptic boutons. The Ca2+ transients matured over several hours into regular low-frequency (0.03 Hz) oscillations. In vivo imaging of intact embryos of both sexes revealed that the formation of ectopic filopodia is increased in Sema2a heterozygotes. We provide genetic evidence suggesting a complex presynaptic Ca2+-dependent signaling network underlying refinement that involves the phosphatases calcineurin and protein phosphatase-1, as well the serine/threonine kinases CaMKII and PKA. Significantly, this network influenced the neuron's response to the muscle's Sema2a chemorepellant, critical for the removal of off-target contacts.SIGNIFICANCE STATEMENT To address the question of how synaptic connectivity is established during development, we examined the behavior of growth cone filopodia during the exploration of both correct and off-target muscle fibers in Drosophila embryos. We demonstrate that filopodia repeatedly contact off-target muscles over several hours, until they ultimately retract. We show that intracellular signals are observed in motile and stabilized "ectopic" contacts. Several genetic experiments provide insight in the molecular pathway underlying network refinement, which includes oscillatory calcium signals via voltage-gated calcium channels as a key component. Calcium orchestrates the activity of several kinases and phosphatases, which interact in a coordinated fashion to regulate chemorepulsion exerted by the muscle.
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Vonhoff F, Keshishian H. Activity-Dependent Synaptic Refinement: New Insights from Drosophila. Front Syst Neurosci 2017; 11:23. [PMID: 28484377 PMCID: PMC5399093 DOI: 10.3389/fnsys.2017.00023] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2017] [Accepted: 04/03/2017] [Indexed: 01/26/2023] Open
Abstract
During development, neurons establish inappropriate connections as they seek out their synaptic partners, resulting in supernumerary synapses that must be pruned away. The removal of miswired synapses usually involves electrical activity, often through a Hebbian spike-timing mechanism. A novel form of activity-dependent refinement is used by Drosophila that may be non-Hebbian, and is critical for generating the precise connectivity observed in that system. In Drosophila, motoneurons use both glutamate and the biogenic amine octopamine for neurotransmission, and the muscle fibers receive multiple synaptic inputs. Motoneuron growth cones respond in a time-regulated fashion to multiple chemotropic signals arising from their postsynaptic partners. Central to this mechanism is a very low frequency (<0.03 Hz) oscillation of presynaptic cytoplasmic calcium, that regulates and coordinates the action of multiple downstream effectors involved in the withdrawal from off-target contacts. Low frequency calcium oscillations are widely observed in developing neural circuits in mammals, and have been shown to be critical for normal connectivity in a variety of neural systems. In Drosophila these mechanisms allow the growth cone to sample widely among possible synaptic partners, evaluate opponent chemotropic signals, and withdraw from off-target contacts. It is possible that the underlying molecular mechanisms are conserved widely among invertebrates and vertebrates.
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Affiliation(s)
- Fernando Vonhoff
- Department of Molecular, Cellular and Developmental Biology, Yale UniversityNew Haven, CT, USA
| | - Haig Keshishian
- Department of Molecular, Cellular and Developmental Biology, Yale UniversityNew Haven, CT, USA
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38
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Chakraborty S, Elvezio V, Kaczocha M, Rebecchi M, Puopolo M. Presynaptic inhibition of transient receptor potential vanilloid type 1 (TRPV1) receptors by noradrenaline in nociceptive neurons. J Physiol 2017; 595:2639-2660. [PMID: 28094445 DOI: 10.1113/jp273455] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2016] [Accepted: 12/23/2016] [Indexed: 12/20/2022] Open
Abstract
KEY POINTS The transient receptor potential vanilloid type 1 (TRPV1) receptor is a polymodal molecular integrator in the pain pathway expressed in Aδ- and C-fibre nociceptors and is responsible for the thermal hyperalgesia associated with inflammatory pain. Noradrenaline strongly inhibited the activity of TRPV1 channels in dorsal root ganglia neurons. The effect of noradrenaline was reproduced by clonidine and antagonized by yohimbine, consistent with contribution of α2 adrenergic receptors. The inhibitory effect of noradrenaline on TRPV1 channels was dependent on calcium influx and linked to calcium/calmodulin-dependent protein kinase II. In spinal cord slices, clonidine reduced the frequency of capsaicin-induced miniature EPSCs in the presence of tetrodotoxin and ω-conotoxin-MVIIC, consistent with inhibition of presynaptic TRPV1 channels by α2 adrenergic receptors. We suggest that modulation of presynaptic TRPV1 channels in nociceptive neurons by descending noradrenergic inputs may constitute a mechanism for noradrenaline to modulate incoming noxious stimuli in the dorsal horn of the spinal cord. ABSTRACT The transient receptor potential vanilloid type 1 (TRPV1) receptor is a well-known contributor to nociceptor excitability. To address whether noradrenaline can down-regulate TRPV1 channel activity in nociceptors and reduce their synaptic transmission, the effects of noradrenaline and clonidine were tested on the capsaicin-activated current recorded from acutely dissociated small diameter (<27 μm) dorsal root ganglia (DRG) neurons and on miniature (m)EPSCs recorded from large lamina I neurons in horizontal spinal cord slices. Noradrenaline or clonidine inhibited the capsaicin-activated current by ∼60%, and the effect was reversed by yohimbine, confirming that it was mediated by activation of α2 adrenergic receptors. Similarly, clonidine reduced the frequency of capsaicin-induced mEPSCs by ∼60%. Inhibition of capsaicin-activated current by noradrenaline was mediated by GTP binding proteins, and was highly dependent on calcium influx. The inhibitory effect of noradrenaline on the capsaicin-activated current was not affected either by blocking the activity of protein kinase A with H89, or by blocking the activity of protein kinase C with bisindolylmaleimide II. In contrast, when the calcium/calmodulin-dependent protein kinase II (CaMKII) was blocked with KN-93, the inhibitory effect of noradrenaline on the capsaicin-activated current was greatly reduced, suggesting that activation of adrenergic receptors in DRG neurons is preferentially linked to CaMKII activity. We suggest that modulation of TRPV1 channels by noradrenaline in nociceptive neurons is a mechanism whereby noradrenaline may suppress incoming noxious stimuli at the primary synaptic afferents in the dorsal horn of the spinal cord.
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Affiliation(s)
- Saikat Chakraborty
- Department of Anesthesiology, Stony Brook Medicine, Stony Brook, NY, 11794, USA.,Present address: Department of Biochemistry, Rush University Medical Center, Cohn Research Building, 1735 W. Harrison St., Chicago, IL, 60612, USA
| | - Vincent Elvezio
- Department of Anesthesiology, Stony Brook Medicine, Stony Brook, NY, 11794, USA
| | - Martin Kaczocha
- Department of Anesthesiology, Stony Brook Medicine, Stony Brook, NY, 11794, USA
| | - Mario Rebecchi
- Department of Anesthesiology, Stony Brook Medicine, Stony Brook, NY, 11794, USA
| | - Michelino Puopolo
- Department of Anesthesiology, Stony Brook Medicine, Stony Brook, NY, 11794, USA
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Salgado VL. Insect TRP channels as targets for insecticides and repellents. JOURNAL OF PESTICIDE SCIENCE 2017; 42:1-6. [PMID: 30363111 PMCID: PMC6140660 DOI: 10.1584/jpestics.d16-104] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2016] [Accepted: 12/19/2016] [Indexed: 05/04/2023]
Abstract
This review provides a brief overview of ion channels, then focuses on TRP channels, describing the properties and functions of the seven TRP channel classes found in insects. Finally, recent work showing that a heteromeric channel composed of Nanchung and Inactive vanilloid TRP (TRPV) channel subunits is the target of the selective feeding blockers pymetrozine and pyrifluquinazon is described. The possible utility of other TRP channels as targets of insecticides and repellents is also considered.
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TRPV1 activation counters diet-induced obesity through sirtuin-1 activation and PRDM-16 deacetylation in brown adipose tissue. Int J Obes (Lond) 2017; 41:739-749. [PMID: 28104916 PMCID: PMC5413365 DOI: 10.1038/ijo.2017.16] [Citation(s) in RCA: 69] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/26/2016] [Revised: 12/03/2016] [Accepted: 01/01/2017] [Indexed: 12/23/2022]
Abstract
Background/Objective An imbalance between energy intake and expenditure leads to obesity. Increasing metabolism and thermogenesis in brown adipose tissue (BAT) can help in overcoming obesity. Here, we investigated the effect of activation of transient receptor potential vanilloid subfamily 1 (TRPV1) in the upregulation of thermogenic proteins in BAT to counter diet-induced obesity. Subjects/Methods We investigated the effect of dietary supplementation of capsaicin (TRPV1 agonist) on the expression of metabolically important thermogenic proteins in BAT of wild type and TRPV1−/− mice that received either a normal chow or high fat (± capsaicin; TRPV1 activator) diet by immunoblotting. We measured the metabolic activity, respiratory quotient and BAT lipolysis. Results CAP antagonized high fat diet (HFD)-induced obesity without decreasing energy intake in mice. HFD suppressed TRPV1 expression and activity in BAT and CAP countered this effect. HFD feeding caused glucose intolerance, hypercholesterolemia and decreased the plasma concentration of glucagon like peptide-1 and CAP countered these effects. HFD suppressed the expression of metabolically important thermogenic genes, ucp-1, bmp8b, sirtuin 1, pgc-1α and prdm-16 in BAT and CAP prevented this effect. CAP increased the phosphorylation of sirtuin 1 and induced an interaction between PPARγ with PRDM-16. Further, CAP treatment, in vitro, decreased the acetylation of PRDM-16, which was antagonized by inhibition of TRPV1 by capsazepine, chelation of intracellular Ca2+ by cell permeable BAPTA-AM or the inhibition of SIRT-1 by EX 527. Further, CAP supplementation, post HFD, promoted weight loss and enhanced the respiratory exchange ratio. CAP did not have any effect in TRPV1−/− mice. Conclusions Our data show that activation of TRPV1 in BAT enhances the expression of SIRT-1, which facilitates the deacetylation and interaction of PPARγ and PRDM-16. These data suggest that TRPV1 activation is a novel strategy to counter diet-induced obesity by enhancing metabolism and energy expenditure.
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41
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Ding Y, Ling J, Qiao Y, Li Z, Sun Z, Cai J, Guo Y, Wang H. A high-throughput fluorimetric microarray with enhanced fluorescence and suppressed "coffee-ring" effects for the detection of calcium ions in blood. Sci Rep 2016; 6:38602. [PMID: 27917959 PMCID: PMC5137002 DOI: 10.1038/srep38602] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2016] [Accepted: 11/09/2016] [Indexed: 01/29/2023] Open
Abstract
A rapid, ultrasensitive, and high-throughput fluorimetric microarray method has been developed using hydrophobic pattern as the microarray substrate and 3-aminopropyltriethoxysilane-coupled carboxylic acid calcium (APS-CCA) as the fluorescent probes for sensing Ca2+ ions in blood. The hydrophobic pattern of the developed Ca2+ analysis microarray could largely suppress the "coffee-ring" effects to facilitate the better distribution density of testing microspots toward the high-throughput detections, and especially prevent the cross-contamination of the multiple samples between adjacent microspots. Moreover, the use of APS matrix could endow the CCA probe the enhanced environmental stability and fluorescence intensity, which is about 2.3-fold higher than that of free CCA. The interactions between APS-CCA and Ca2+ ions were systematically characterized by UV-vis and fluorescence measurements including microscopy imaging. It was demonstrated that the fluorimetric microarray could display the strong capacity of specifically sensing Ca2+ ions with the minimal interferences from blood backgrounds. Such an APS-CCA-based fluorimetric microarray can allow for the analysis of Ca2+ ions down to 0.0050 mM in blood, promising a highly sensitive and selective detection candidate for Ca2+ ions to be applied in the clinical laboratory.
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Affiliation(s)
- Yanjun Ding
- Department of Forensic Science, School of Basic Medical Sciences, Central South University, Changsha 410013, Hunan, China
| | - Jiang Ling
- Department of Forensic Science, School of Basic Medical Sciences, Central South University, Changsha 410013, Hunan, China
- College of Chemistry and Chemical Engineering, Qufu Normal University, Qufu 273165, P. R. China
| | - Yuchun Qiao
- College of Chemistry and Chemical Engineering, Qufu Normal University, Qufu 273165, P. R. China
| | - Zhengjian Li
- College of Chemistry and Chemical Engineering, Qufu Normal University, Qufu 273165, P. R. China
| | - Zongzhao Sun
- College of Chemistry and Chemical Engineering, Qufu Normal University, Qufu 273165, P. R. China
| | - Jifeng Cai
- Department of Forensic Science, School of Basic Medical Sciences, Central South University, Changsha 410013, Hunan, China
| | - Yadong Guo
- Department of Forensic Science, School of Basic Medical Sciences, Central South University, Changsha 410013, Hunan, China
| | - Hua Wang
- College of Chemistry and Chemical Engineering, Qufu Normal University, Qufu 273165, P. R. China
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42
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Effects of a TRPV1 agonist capsaicin on respiratory rhythm generation in brainstem-spinal cord preparation from newborn rats. Pflugers Arch 2016; 469:327-338. [PMID: 27900462 DOI: 10.1007/s00424-016-1912-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2016] [Revised: 11/20/2016] [Accepted: 11/22/2016] [Indexed: 12/19/2022]
Abstract
The heat-sensitive transient receptor potential vanilloid 1 (TRPV1) channels are expressed in the peripheral and central nervous systems. However, there is no report on how the activation of TRPV1 causes the modulation of neuronal activity in the medullary respiratory center. We examined effects of capsaicin, a specific agonist of TRPV1 channels, on respiratory rhythm generation in brainstem-spinal cord preparation from newborn rats. Capsaicin induced a biphasic response in the respiratory rhythm (a transient decrease followed by an increase in the C4 rate). The second-phase excitatory effect (but not the initial inhibitory effect) in the biphasic response was partly blocked by capsazepine or AMG9810 (TRPV1 antagonists). Capsaicin caused strong desensitization. After its washout, the strength of C4 burst inspiratory activity was augmented once per four to five respiratory cycles. The preinspiratory and inspiratory neurons showed tonic firings due to membrane depolarization during the initial inhibitory phase. In the presence of TTX, capsaicin increased the fluctuation of the membrane potential of the CO2-sensitive preinspiratory neurons in the parafacial respiratory group (pFRG), accompanied by slight depolarization. The C4 inspiratory activity did not stop, even 60-90 min after the application of 50/100 μM capsaicin. Voltage-sensitive dye imaging demonstrated that the spatiotemporal pattern of the respiratory rhythm generating networks after application of capsaicin (50 μM, 70-90 min) was highly similar to the control. A histochemical analysis using TRPV1 channel protein antibodies and mRNA demonstrated that the TRPV1 channel-positive cells were widely distributed in the reticular formation of the medulla, including the pFRG. Our results showed that the application of capsaicin in the medulla has various influences on the respiratory center: transient inhibitory and subsequent excitatory effects on the respiratory rhythm and periodical augmentation of the inspiratory burst pattern. The effects of capsaicin were partially blocked by TRPV1 antagonists but could be also induced at least partially via the non-specific action. Our results also suggested a minor contribution of the TRPV1 channels to central chemoreception.
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The Emerging Roles of the Calcineurin-Nuclear Factor of Activated T-Lymphocytes Pathway in Nervous System Functions and Diseases. J Aging Res 2016; 2016:5081021. [PMID: 27597899 PMCID: PMC5002468 DOI: 10.1155/2016/5081021] [Citation(s) in RCA: 64] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2016] [Accepted: 07/21/2016] [Indexed: 12/27/2022] Open
Abstract
The ongoing epidemics of metabolic diseases and increase in the older population have increased the incidences of neurodegenerative diseases. Evidence from murine and cell line models has implicated calcineurin-nuclear factor of activated T-lymphocytes (NFAT) signaling pathway, a Ca2+/calmodulin-dependent major proinflammatory pathway, in the pathogenesis of these diseases. Neurotoxins such as amyloid-β, tau protein, and α-synuclein trigger abnormal calcineurin/NFAT signaling activities. Additionally increased activities of endogenous regulators of calcineurin like plasma membrane Ca2+-ATPase (PMCA) and regulator of calcineurin 1 (RCAN1) also cause neuronal and glial loss and related functional alterations, in neurodegenerative diseases, psychotic disorders, epilepsy, and traumatic brain and spinal cord injuries. Treatment with calcineurin/NFAT inhibitors induces some degree of neuroprotection and decreased reactive gliosis in the central and peripheral nervous system. In this paper, we summarize and discuss the current understanding of the roles of calcineurin/NFAT signaling in physiology and pathologies of the adult and developing nervous system, with an emphasis on recent reports and cutting-edge findings. Calcineurin/NFAT signaling is known for its critical roles in the developing and adult nervous system. Its role in physiological and pathological processes is still controversial. However, available data suggest that its beneficial and detrimental effects are context-dependent. In view of recent reports calcineurin/NFAT signaling is likely to serve as a potential therapeutic target for neurodegenerative diseases and conditions. This review further highlights the need to characterize better all factors determining the outcome of calcineurin/NFAT signaling in diseases and the downstream targets mediating the beneficial and detrimental effects.
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44
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Bodaleo FJ, Gonzalez-Billault C. The Presynaptic Microtubule Cytoskeleton in Physiological and Pathological Conditions: Lessons from Drosophila Fragile X Syndrome and Hereditary Spastic Paraplegias. Front Mol Neurosci 2016; 9:60. [PMID: 27504085 PMCID: PMC4958632 DOI: 10.3389/fnmol.2016.00060] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2016] [Accepted: 07/11/2016] [Indexed: 11/21/2022] Open
Abstract
The capacity of the nervous system to generate neuronal networks relies on the establishment and maintenance of synaptic contacts. Synapses are composed of functionally different presynaptic and postsynaptic compartments. An appropriate synaptic architecture is required to provide the structural basis that supports synaptic transmission, a process involving changes in cytoskeletal dynamics. Actin microfilaments are the main cytoskeletal components present at both presynaptic and postsynaptic terminals in glutamatergic synapses. However, in the last few years it has been demonstrated that microtubules (MTs) transiently invade dendritic spines, promoting their maturation. Nevertheless, the presence and functions of MTs at the presynaptic site are still a matter of debate. Early electron microscopy (EM) studies revealed that MTs are present in the presynaptic terminals of the central nervous system (CNS) where they interact with synaptic vesicles (SVs) and reach the active zone. These observations have been reproduced by several EM protocols; however, there is empirical heterogeneity in detecting presynaptic MTs, since they appear to be both labile and unstable. Moreover, increasing evidence derived from studies in the fruit fly neuromuscular junction proposes different roles for MTs in regulating presynaptic function in physiological and pathological conditions. In this review, we summarize the main findings that support the presence and roles of MTs at presynaptic terminals, integrating descriptive and biochemical analyses, and studies performed in invertebrate genetic models.
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Affiliation(s)
- Felipe J Bodaleo
- Laboratory of Cell and Neuronal Dynamics, Department of Biology, Faculty of Sciences, Universidad de ChileSantiago, Chile; Center for Geroscience, Brain Health and Metabolism (GERO)Santiago, Chile
| | - Christian Gonzalez-Billault
- Laboratory of Cell and Neuronal Dynamics, Department of Biology, Faculty of Sciences, Universidad de ChileSantiago, Chile; Center for Geroscience, Brain Health and Metabolism (GERO)Santiago, Chile; The Buck Institute for Research on Aging, NovatoCA, USA
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45
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Summerville JB, Faust JF, Fan E, Pendin D, Daga A, Formella J, Stern M, McNew JA. The effects of ER morphology on synaptic structure and function in Drosophila melanogaster. J Cell Sci 2016; 129:1635-48. [PMID: 26906425 DOI: 10.1242/jcs.184929] [Citation(s) in RCA: 61] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2015] [Accepted: 02/17/2016] [Indexed: 01/21/2023] Open
Abstract
Hereditary spastic paraplegia (HSP) is a set of genetic diseases caused by mutations in one of 72 genes that results in age-dependent corticospinal axon degeneration accompanied by spasticity and paralysis. Two genes implicated in HSPs encode proteins that regulate endoplasmic reticulum (ER) morphology. Atlastin 1 (ATL1, also known as SPG3A) encodes an ER membrane fusion GTPase and reticulon 2 (RTN2, also known as SPG12) helps shape ER tube formation. Here, we use a new fluorescent ER marker to show that the ER within wild-type Drosophila motor nerve terminals forms a network of tubules that is fragmented and made diffuse upon loss of the atlastin 1 ortholog atl. atl or Rtnl1 loss decreases evoked transmitter release and increases arborization. Similar to other HSP proteins, Atl inhibits bone morphogenetic protein (BMP) signaling, and loss of atl causes age-dependent locomotor deficits in adults. These results demonstrate a crucial role for ER in neuronal function, and identify mechanistic links between ER morphology, neuronal function, BMP signaling and adult behavior.
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Affiliation(s)
- James B Summerville
- Department of BioSciences, Program in Biochemistry and Cell Biology, Rice University, Houston, TX 77005, USA
| | - Joseph F Faust
- Department of BioSciences, Program in Biochemistry and Cell Biology, Rice University, Houston, TX 77005, USA
| | - Ethan Fan
- Department of BioSciences, Program in Biochemistry and Cell Biology, Rice University, Houston, TX 77005, USA
| | - Diana Pendin
- CNR, Neuroscience Institute, 35121 Padova, Italy
| | - Andrea Daga
- E. Medea Scientific Institute, 31015 Conegliano, Italy
| | - Joseph Formella
- Department of BioSciences, Program in Biochemistry and Cell Biology, Rice University, Houston, TX 77005, USA
| | - Michael Stern
- Department of BioSciences, Program in Biochemistry and Cell Biology, Rice University, Houston, TX 77005, USA
| | - James A McNew
- Department of BioSciences, Program in Biochemistry and Cell Biology, Rice University, Houston, TX 77005, USA
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Chakraborty S, Rebecchi M, Kaczocha M, Puopolo M. Dopamine modulation of transient receptor potential vanilloid type 1 (TRPV1) receptor in dorsal root ganglia neurons. J Physiol 2016; 594:1627-42. [PMID: 26563747 DOI: 10.1113/jp271198] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2015] [Accepted: 11/04/2015] [Indexed: 01/11/2023] Open
Abstract
The transient receptor potential vanilloid type 1 (TRPV1) receptor plays a key role in the modulation of nociceptor excitability. To address whether dopamine can modulate the activity of TRPV1 channels in nociceptive neurons, the effects of dopamine and dopamine receptor agonists were tested on the capsaicin-activated current recorded from acutely dissociated small diameter (<27 μm) dorsal root ganglia (DRG) neurons. Dopamine or SKF 81297 (an agonist at D1/D5 receptors), caused inhibition of both inward and outward currents by ∼60% and ∼48%, respectively. The effect of SKF 81297 was reversed by SCH 23390 (an antagonist at D1/D5 receptors), confirming that it was mediated by activation of D1/D5 dopamine receptors. In contrast, quinpirole (an agonist at D2 receptors) had no significant effect on the capsaicin-activated current. Inhibition of the capsaicin-activated current by SKF 81297 was mediated by G protein coupled receptors (GPCRs), and highly dependent on external calcium. The inhibitory effect of SKF 81297 on the capsaicin-activated current was not affected when the protein kinase A (PKA) activity was blocked with H89, or when the protein kinase C (PKC) activity was blocked with bisindolylmaleimide II (BIM). In contrast, when the calcium-calmodulin-dependent protein kinase II (CaMKII) was blocked with KN-93, the inhibitory effect of SKF 81297 on the capsaicin-activated current was greatly reduced, suggesting that activation of D1/D5 dopamine receptors may be preferentially linked to CaMKII activity. We suggest that modulation of TRPV1 channels by dopamine in nociceptive neurons may represent a way for dopamine to modulate incoming noxious stimuli.
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Affiliation(s)
- Saikat Chakraborty
- Department of Anesthesiology, Stony Brook Medicine, Stony Brook, NY, 11794, USA
| | - Mario Rebecchi
- Department of Anesthesiology, Stony Brook Medicine, Stony Brook, NY, 11794, USA
| | - Martin Kaczocha
- Department of Anesthesiology, Stony Brook Medicine, Stony Brook, NY, 11794, USA
| | - Michelino Puopolo
- Department of Anesthesiology, Stony Brook Medicine, Stony Brook, NY, 11794, USA
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Deshpande M, Rodal AA. The Crossroads of Synaptic Growth Signaling, Membrane Traffic and Neurological Disease: Insights from Drosophila. Traffic 2015; 17:87-101. [PMID: 26538429 DOI: 10.1111/tra.12345] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2015] [Revised: 10/29/2015] [Accepted: 10/29/2015] [Indexed: 12/13/2022]
Abstract
Neurons require target-derived autocrine and paracrine growth factors to maintain proper identity, innervation, homeostasis and survival. Neuronal growth factor signaling is highly dependent on membrane traffic, both for the packaging and release of the growth factors themselves, and for regulation of intracellular signaling by their transmembrane receptors. Here, we review recent findings from the Drosophila larval neuromuscular junction (NMJ) that illustrate how specific steps of intracellular traffic and inter-organelle interactions impinge on signaling, particularly in the bone morphogenic protein, Wingless and c-Jun-activated kinase pathways, regulating elaboration and stability of NMJ arbors, construction of synapses and synaptic transmission and homeostasis. These membrane trafficking and signaling pathways have been implicated in human motor neuron diseases including amyotrophic lateral sclerosis and hereditary spastic paraplegia, highlighting their importance for neuronal health and survival.
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Affiliation(s)
| | - Avital A Rodal
- Department of Biology, Brandeis University, Waltham, MA, USA
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48
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Signal integration by Ca(2+) regulates intestinal stem-cell activity. Nature 2015; 528:212-7. [PMID: 26633624 PMCID: PMC4669953 DOI: 10.1038/nature16170] [Citation(s) in RCA: 120] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2014] [Accepted: 10/30/2015] [Indexed: 01/05/2023]
Abstract
Somatic stem cells (SCs) maintain tissue homeostasis by dynamically adjusting proliferation and differentiation in response to stress and metabolic cues. Here, we identify Ca2+ signaling as a central regulator of intestinal SC (ISC) activity in Drosophila. We find that dietary L-glutamate stimulates ISC division and gut growth. The metabotropic glutamate receptor (mGluR) is required in ISCs for this response and for an associated modulation of cytosolic Ca2+ oscillations that results in sustained high cytosolic Ca2+ concentrations. High cytosolic Ca2+ induces ISC proliferation by regulating Calcineurin and CREB - regulated transcriptional co-activator (CRTC). In response to a wide range of dietary and stress stimuli, ISCs reversibly transition between Ca2+ oscillation states that represent poised or activated modes of proliferation, respectively. We propose that the dynamic regulation of intracellular Ca2+ levels allows effective integration of diverse mitogenic signals in ISCs to tailor their proliferative activity to the needs of the tissue.
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Wong CO, Palmieri M, Li J, Akhmedov D, Chao Y, Broadhead GT, Zhu MX, Berdeaux R, Collins CA, Sardiello M, Venkatachalam K. Diminished MTORC1-Dependent JNK Activation Underlies the Neurodevelopmental Defects Associated with Lysosomal Dysfunction. Cell Rep 2015; 12:2009-20. [PMID: 26387958 DOI: 10.1016/j.celrep.2015.08.047] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2015] [Revised: 07/20/2015] [Accepted: 08/14/2015] [Indexed: 12/12/2022] Open
Abstract
Here, we evaluate the mechanisms underlying the neurodevelopmental deficits in Drosophila and mouse models of lysosomal storage diseases (LSDs). We find that lysosomes promote the growth of neuromuscular junctions (NMJs) via Rag GTPases and mechanistic target of rapamycin complex 1 (MTORC1). However, rather than employing S6K/4E-BP1, MTORC1 stimulates NMJ growth via JNK, a determinant of axonal growth in Drosophila and mammals. This role of lysosomal function in regulating JNK phosphorylation is conserved in mammals. Despite requiring the amino-acid-responsive kinase MTORC1, NMJ development is insensitive to dietary protein. We attribute this paradox to anaplastic lymphoma kinase (ALK), which restricts neuronal amino acid uptake, and the administration of an ALK inhibitor couples NMJ development to dietary protein. Our findings provide an explanation for the neurodevelopmental deficits in LSDs and suggest an actionable target for treatment.
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Affiliation(s)
- Ching-On Wong
- Department of Integrative Biology and Pharmacology, University of Texas School of Medicine, Houston, TX 77030, USA
| | - Michela Palmieri
- Department of Molecular and Human Genetics, Baylor College of Medicine, Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, Texas, TX 77030, USA
| | - Jiaxing Li
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Dmitry Akhmedov
- Department of Integrative Biology and Pharmacology, University of Texas School of Medicine, Houston, TX 77030, USA
| | - Yufang Chao
- Department of Integrative Biology and Pharmacology, University of Texas School of Medicine, Houston, TX 77030, USA
| | - Geoffrey T Broadhead
- Department of Integrative Biology and Pharmacology, University of Texas School of Medicine, Houston, TX 77030, USA
| | - Michael X Zhu
- Department of Integrative Biology and Pharmacology, University of Texas School of Medicine, Houston, TX 77030, USA; Program in Cell and Regulatory Biology (CRB), Graduate School of Biomedical Sciences, University of Texas School of Medicine, Houston, TX 77030, USA
| | - Rebecca Berdeaux
- Department of Integrative Biology and Pharmacology, University of Texas School of Medicine, Houston, TX 77030, USA; Program in Cell and Regulatory Biology (CRB), Graduate School of Biomedical Sciences, University of Texas School of Medicine, Houston, TX 77030, USA
| | - Catherine A Collins
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Marco Sardiello
- Department of Molecular and Human Genetics, Baylor College of Medicine, Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, Texas, TX 77030, USA
| | - Kartik Venkatachalam
- Department of Integrative Biology and Pharmacology, University of Texas School of Medicine, Houston, TX 77030, USA; Program in Cell and Regulatory Biology (CRB), Graduate School of Biomedical Sciences, University of Texas School of Medicine, Houston, TX 77030, USA; Program in Neuroscience, Graduate School of Biomedical Sciences, University of Texas School of Medicine, Houston, TX 77030, USA.
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Nesterov A, Spalthoff C, Kandasamy R, Katana R, Rankl N, Andrés M, Jähde P, Dorsch J, Stam L, Braun FJ, Warren B, Salgado V, Göpfert M. TRP Channels in Insect Stretch Receptors as Insecticide Targets. Neuron 2015; 86:665-71. [DOI: 10.1016/j.neuron.2015.04.001] [Citation(s) in RCA: 89] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2014] [Revised: 01/13/2015] [Accepted: 03/10/2015] [Indexed: 01/06/2023]
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