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Yarikipati P, Jonusaite S, Pleinis JM, Dominicci Cotto C, Sanchez-Hernandez D, Morrison DE, Goyal S, Schellinger J, Pénalva C, Curtiss J, Rodan AR, Jenny A. Unanticipated domain requirements for Drosophila Wnk kinase in vivo. PLoS Genet 2023; 19:e1010975. [PMID: 37819975 PMCID: PMC10593226 DOI: 10.1371/journal.pgen.1010975] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Revised: 10/23/2023] [Accepted: 09/14/2023] [Indexed: 10/13/2023] Open
Abstract
WNK (With no Lysine [K]) kinases have critical roles in the maintenance of ion homeostasis and the regulation of cell volume. Their overactivation leads to pseudohypoaldosteronism type II (Gordon syndrome) characterized by hyperkalemia and high blood pressure. More recently, WNK family members have been shown to be required for the development of the nervous system in mice, zebrafish, and flies, and the cardiovascular system of mice and fish. Furthermore, human WNK2 and Drosophila Wnk modulate canonical Wnt signaling. In addition to a well-conserved kinase domain, animal WNKs have a large, poorly conserved C-terminal domain whose function has been largely mysterious. In most but not all cases, WNKs bind and activate downstream kinases OSR1/SPAK, which in turn regulate the activity of various ion transporters and channels. Here, we show that Drosophila Wnk regulates Wnt signaling and cell size during the development of the wing in a manner dependent on Fray, the fly homolog of OSR1/SPAK. We show that the only canonical RF(X)V/I motif of Wnk, thought to be essential for WNK interactions with OSR1/SPAK, is required to interact with Fray in vitro. However, this motif is unexpectedly dispensable for Fray-dependent Wnk functions in vivo during fly development and fluid secretion in the Malpighian (renal) tubules. In contrast, a structure function analysis of Wnk revealed that the less-conserved C-terminus of Wnk, that recently has been shown to promote phase transitions in cell culture, is required for viability in vivo. Our data thus provide novel insights into unexpected in vivo roles of specific WNK domains.
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Affiliation(s)
- Prathibha Yarikipati
- Department of Developmental and Molecular Biology, Albert Einstein College of Medicine, New York, United States of America
| | - Sima Jonusaite
- Molecular Medicine Program, University of Utah, Salt Lake City, Utah, United States of America
| | - John M. Pleinis
- Molecular Medicine Program, University of Utah, Salt Lake City, Utah, United States of America
| | - Carihann Dominicci Cotto
- Department of Developmental and Molecular Biology, Albert Einstein College of Medicine, New York, United States of America
| | - David Sanchez-Hernandez
- Department of Developmental and Molecular Biology, Albert Einstein College of Medicine, New York, United States of America
| | - Daryl E. Morrison
- Molecular Medicine Program, University of Utah, Salt Lake City, Utah, United States of America
| | - Suhani Goyal
- Department of Internal Medicine, Division of Nephrology, University of Texas Southwestern, Dallas, Texas, United States of America
| | - Jeffrey Schellinger
- Department of Internal Medicine, Division of Nephrology, University of Texas Southwestern, Dallas, Texas, United States of America
| | - Clothilde Pénalva
- Molecular Medicine Program, University of Utah, Salt Lake City, Utah, United States of America
| | - Jennifer Curtiss
- Department of Cell & Developmental Biology, New Mexico State University, Las Cruces, New Mexico, United States of America
| | - Aylin R. Rodan
- Molecular Medicine Program, University of Utah, Salt Lake City, Utah, United States of America
- Department of Internal Medicine, Division of Nephrology and Hypertension, University of Utah, Salt Lake City, Utah, United States of America
- Department of Human Genetics, University of Utah, Salt Lake City, Utah, United States of America
- Medical Service, Veterans Affairs Salt Lake City Health Care System, Salt Lake City, Utah, United States of America
| | - Andreas Jenny
- Department of Developmental and Molecular Biology, Albert Einstein College of Medicine, New York, United States of America
- Department of Genetics, Albert Einstein College of Medicine, New York, New York, United States of America
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2
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Chen R, Swale DR. Functional interactions between potassium-chloride cotransporter (KCC) and inward rectifier potassium (Kir) channels in the insect central nervous system. PESTICIDE BIOCHEMISTRY AND PHYSIOLOGY 2023; 192:105389. [PMID: 37105628 DOI: 10.1016/j.pestbp.2023.105389] [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: 01/12/2023] [Revised: 03/07/2023] [Accepted: 03/07/2023] [Indexed: 06/19/2023]
Abstract
The K+/Cl- cotransporter (KCC) is the primary mechanism by which mature neurons maintain low intracellular chloride (Cl-) concentration and has been shown to be functionally coupled to the GABA-gated chloride channels (GGCC) in Drosophila central neurons. Further, pharmacological inhibition of KCC has been shown to lead to acute toxicity of mosquitoes that highlights the toxicological relevance of insect KCC. Yet, gaps in knowledge remain regarding physiological drivers of KCC function and interactions of ion flux mechanisms upstream of GGCC in insects. Considering this, we employed electrophysiological and fluorescent microscopy techniques to further characterize KCC in the insect nervous system. Fluorescent microscopy indicated insect KCC2 is expressed in rdl neurons, which is the neuron type responsible for GABA-mediated neurotransmission, and are coexpressed with inward rectifier potassium (Kir) 2 channels. Coexpression of Kir2 and KCC2 suggested the possibility of functional coupling between these two K+ flux pathways. Indeed, extracellular recordings of Drosophila CNS showed pre-block of Kir channels prior to block of KCC led to a significant (P < 0.001) increase in CNS firing rates over baseline that when taken together, supports functional coupling of Kir to KCC function. Additionally, we documented a synergistic increase to toxicity of VU0463271, an established KCC inhibitor, above the expected additive toxicity after co-treatment with the Kir inhibitor, VU041. These data expand current knowledge regarding the physiological roles of KCC and Kir channels in the insect nervous system by defining additional pathways that facilitate inhibitory neurotransmission through GGCC.
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Affiliation(s)
- Rui Chen
- Department of Entomology, Louisiana State University AgCenter, Baton Rouge, LA, United States of America
| | - Daniel R Swale
- Department of Entomology, Louisiana State University AgCenter, Baton Rouge, LA, United States of America; Emerging Pathogens Institute, Department of Entomology and Nematology, University of Florida, Gainesville, FL 32610, United States of America.
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3
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Contreras EG, Klämbt C. The Drosophila blood-brain barrier emerges as a model for understanding human brain diseases. Neurobiol Dis 2023; 180:106071. [PMID: 36898613 DOI: 10.1016/j.nbd.2023.106071] [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: 12/29/2022] [Revised: 02/24/2023] [Accepted: 03/07/2023] [Indexed: 03/12/2023] Open
Abstract
The accurate regulation of the microenvironment within the nervous system is one of the key features characterizing complex organisms. To this end, neural tissue has to be physically separated from circulation, but at the same time, mechanisms must be in place to allow controlled transport of nutrients and macromolecules into and out of the brain. These roles are executed by cells of the blood-brain barrier (BBB) found at the interface of circulation and neural tissue. BBB dysfunction is observed in several neurological diseases in human. Although this can be considered as a consequence of diseases, strong evidence supports the notion that BBB dysfunction can promote the progression of brain disorders. In this review, we compile the recent evidence describing the contribution of the Drosophila BBB to the further understanding of brain disease features in human patients. We discuss the function of the Drosophila BBB during infection and inflammation, drug clearance and addictions, sleep, chronic neurodegenerative disorders and epilepsy. In summary, this evidence suggests that the fruit fly, Drosophila melanogaster, can be successfully employed as a model to disentangle mechanisms underlying human diseases.
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Affiliation(s)
- Esteban G Contreras
- University of Münster, Institute of Neuro- and Behavioral Biology, Badestr. 9, Münster, Germany.
| | - Christian Klämbt
- University of Münster, Institute of Neuro- and Behavioral Biology, Badestr. 9, Münster, Germany.
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4
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SIK3 and Wnk converge on Fray to regulate glial K+ buffering and seizure susceptibility. PLoS Genet 2023; 19:e1010581. [PMID: 36626385 PMCID: PMC9870106 DOI: 10.1371/journal.pgen.1010581] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2022] [Revised: 01/23/2023] [Accepted: 12/19/2022] [Indexed: 01/11/2023] Open
Abstract
Glial cells play a critical role in maintaining homeostatic ion concentration gradients. Salt-inducible kinase 3 (SIK3) regulates a gene expression program that controls K+ buffering in glia, and upregulation of this pathway suppresses seizure behavior in the eag, Shaker hyperexcitability mutant. Here we show that boosting the glial SIK3 K+ buffering pathway suppresses seizures in three additional molecularly diverse hyperexcitable mutants, highlighting the therapeutic potential of upregulating glial K+ buffering. We then explore additional mechanisms regulating glial K+ buffering. Fray, a transcriptional target of the SIK3 K+ buffering program, is a kinase that promotes K+ uptake by activating the Na+/K+/Cl- co-transporter, Ncc69. We show that the Wnk kinase phosphorylates Fray in Drosophila glia and that this activity is required to promote K+ buffering. This identifies Fray as a convergence point between the SIK3-dependent transcriptional program and Wnk-dependent post-translational regulation. Bypassing both regulatory mechanisms via overexpression of a constitutively active Fray in glia is sufficient to robustly suppress seizure behavior in multiple Drosophila models of hyperexcitability. Finally, we identify cortex glia as a critical cell type for regulation of seizure susceptibility, as boosting K+ buffering via expression of activated Fray exclusively in these cells is sufficient to suppress seizure behavior. These findings highlight Fray as a key convergence point for distinct K+ buffering regulatory mechanisms and cortex glia as an important locus for control of neuronal excitability.
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Miao X, Wu J, Chen H, Lu G. Comprehensive Analysis of the Structure and Function of Peptide:N-Glycanase 1 and Relationship with Congenital Disorder of Deglycosylation. Nutrients 2022; 14:nu14091690. [PMID: 35565658 PMCID: PMC9102325 DOI: 10.3390/nu14091690] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2022] [Revised: 04/13/2022] [Accepted: 04/15/2022] [Indexed: 02/01/2023] Open
Abstract
The cytosolic PNGase (peptide:N-glycanase), also known as peptide-N4-(N-acetyl-β-glucosaminyl)-asparagine amidase, is a well-conserved deglycosylation enzyme (EC 3.5.1.52) which catalyzes the non-lysosomal hydrolysis of an N(4)-(acetyl-β-d-glucosaminyl) asparagine residue (Asn, N) into a N-acetyl-β-d-glucosaminyl-amine and a peptide containing an aspartate residue (Asp, D). This enzyme (NGLY1) plays an essential role in the clearance of misfolded or unassembled glycoproteins through a process named ER-associated degradation (ERAD). Accumulating evidence also points out that NGLY1 deficiency can cause an autosomal recessive (AR) human genetic disorder associated with abnormal development and congenital disorder of deglycosylation. In addition, the loss of NGLY1 can affect multiple cellular pathways, including but not limited to NFE2L1 pathway, Creb1/Atf1-AQP pathway, BMP pathway, AMPK pathway, and SLC12A2 ion transporter, which might be the underlying reasons for a constellation of clinical phenotypes of NGLY1 deficiency. The current comprehensive review uncovers the NGLY1’ssdetailed structure and its important roles for participation in ERAD, involvement in CDDG and potential treatment for NGLY1 deficiency.
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Affiliation(s)
- Xiangguang Miao
- Queen Mary School, Nanchang University, No. 1299 Xuefu Avenue, Honggutan New District, Nanchang 330036, China;
| | - Jin Wu
- Laboratory of Translational Medicine Research, Department of Pathology, Deyang People’s Hospital, No. 173 First Section of Taishanbei Road, Jingyang District, Deyang 618000, China;
- Deyang Key Laboratory of Tumor Molecular Research, No. 173 First Section of Taishanbei Road, Jingyang District, Deyang 618000, China
- Department of Molecular & Cellular Biology, Roswell Park Comprehensive Cancer Center, Elm and Carlton Streets, Buffalo, NY 14263, USA
| | - Hongping Chen
- Department of Histology and Embryology, Medical College of Nanchang University, Nanchang 330006, China
- Correspondence: (H.C.); (G.L.); Tel.: +86-188-0147-4087 (G.L.)
| | - Guanting Lu
- Laboratory of Translational Medicine Research, Department of Pathology, Deyang People’s Hospital, No. 173 First Section of Taishanbei Road, Jingyang District, Deyang 618000, China;
- Deyang Key Laboratory of Tumor Molecular Research, No. 173 First Section of Taishanbei Road, Jingyang District, Deyang 618000, China
- Correspondence: (H.C.); (G.L.); Tel.: +86-188-0147-4087 (G.L.)
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Schellinger JN, Sun Q, Pleinis JM, An SW, Hu J, Mercenne G, Titos I, Huang CL, Rothenfluh A, Rodan AR. Chloride oscillation in pacemaker neurons regulates circadian rhythms through a chloride-sensing WNK kinase signaling cascade. Curr Biol 2022; 32:1429-1438.e6. [PMID: 35303418 PMCID: PMC8972083 DOI: 10.1016/j.cub.2022.03.017] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2021] [Revised: 12/02/2021] [Accepted: 03/04/2022] [Indexed: 12/21/2022]
Abstract
Central pacemaker neurons regulate circadian rhythms and undergo diurnal variation in electrical activity in mammals and flies.1,2 Circadian variation in the intracellular chloride concentration of mammalian pacemaker neurons has been proposed to influence the response to GABAergic neurotransmission through GABAA receptor chloride channels.3 However, results have been contradictory,4-9 and a recent study demonstrated circadian variation in pacemaker neuron chloride without an effect on GABA response.10 Therefore, whether and how intracellular chloride regulates circadian rhythms remains controversial. Here, we demonstrate a signaling role for intracellular chloride in the Drosophila small ventral lateral (sLNv) pacemaker neurons. In control flies, intracellular chloride increases in sLNvs over the course of the morning. Chloride transport through sodium-potassium-2-chloride (NKCC) and potassium-chloride (KCC) cotransporters is a major determinant of intracellular chloride concentrations.11Drosophila melanogaster with loss-of-function mutations in the NKCC encoded by Ncc69 have abnormally low intracellular chloride 6 h after lights on, loss of morning anticipation, and a prolonged circadian period. Loss of kcc, which is expected to increase intracellular chloride, suppresses the long-period phenotype of Ncc69 mutant flies. Activation of a chloride-inhibited kinase cascade, consisting of WNK (with no lysine [K]) kinase and its downstream substrate, Fray, is necessary and sufficient to prolong period length. Fray activation of an inwardly rectifying potassium channel, Irk1, is also required for the long-period phenotype. These results indicate that the NKCC-dependent rise in intracellular chloride in Drosophila sLNv pacemakers restrains WNK-Fray signaling and overactivation of an inwardly rectifying potassium channel to maintain normal circadian period length.
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Affiliation(s)
- Jeffrey N Schellinger
- Department of Internal Medicine, Division of Nephrology, University of Texas Southwestern, Dallas, TX 75390, USA
| | - Qifei Sun
- Department of Internal Medicine, Division of Nephrology, University of Texas Southwestern, Dallas, TX 75390, USA
| | - John M Pleinis
- Molecular Medicine Program, University of Utah, Salt Lake City, UT 84112, USA
| | - Sung-Wan An
- Department of Internal Medicine, Division of Nephrology, University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA
| | - Jianrui Hu
- Molecular Medicine Program, University of Utah, Salt Lake City, UT 84112, USA
| | - Gaëlle Mercenne
- Molecular Medicine Program, University of Utah, Salt Lake City, UT 84112, USA
| | - Iris Titos
- Molecular Medicine Program, University of Utah, Salt Lake City, UT 84112, USA
| | - Chou-Long Huang
- Department of Internal Medicine, Division of Nephrology, University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA
| | - Adrian Rothenfluh
- Molecular Medicine Program, University of Utah, Salt Lake City, UT 84112, USA; Department of Psychiatry, Huntsman Mental Health Institute, University of Utah, Salt Lake City, UT 84108, USA; Department of Neurobiology, University of Utah, Salt Lake City, UT 84112, USA; Department of Human Genetics, University of Utah, Salt Lake City, UT 84112, USA
| | - Aylin R Rodan
- Molecular Medicine Program, University of Utah, Salt Lake City, UT 84112, USA; Department of Human Genetics, University of Utah, Salt Lake City, UT 84112, USA; Department of Internal Medicine, Division of Nephrology and Hypertension, University of Utah, Salt Lake City, UT 84132, USA; Medical Service, Veterans Affairs Salt Lake City Health Care System, Salt Lake City, UT 84148, USA.
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7
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Li H, Lones L, DiAntonio A. Bidirectional regulation of glial potassium buffering - glioprotection versus neuroprotection. eLife 2021; 10:62606. [PMID: 33646119 PMCID: PMC7946421 DOI: 10.7554/elife.62606] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2020] [Accepted: 02/26/2021] [Indexed: 11/13/2022] Open
Abstract
Glia modulate neuronal excitability and seizure sensitivity by maintaining potassium and water homeostasis. A salt inducible kinase 3 (SIK3)-regulated gene expression program controls the glial capacity to buffer K+ and water in Drosophila, however upstream regulatory mechanisms are unknown. Here, we identify an octopaminergic circuit linking neuronal activity to glial ion and water buffering. Under basal conditions, octopamine functions through the inhibitory octopaminergic G-protein-coupled receptor (GPCR) OctβR to upregulate glial buffering capacity, while under pathological K+ stress, octopamine signals through the stimulatory octopaminergic GPCR OAMB1 to downregulate the glial buffering program. Failure to downregulate this program leads to intracellular glia swelling and stress signaling, suggesting that turning down this pathway is glioprotective. In the eag shaker Drosophila seizure model, the SIK3-mediated buffering pathway is inactivated. Reactivation of the glial buffering program dramatically suppresses neuronal hyperactivity, seizures, and shortened life span in this mutant. These findings highlight the therapeutic potential of a glial-centric therapeutic strategy for diseases of hyperexcitability.
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Affiliation(s)
- Hailun Li
- Department of Developmental Biology, Washington University in St. Louis School of Medicine, St. Louis, United States
| | - Lorenzo Lones
- Department of Developmental Biology, Washington University in St. Louis School of Medicine, St. Louis, United States
| | - Aaron DiAntonio
- Department of Developmental Biology, Washington University in St. Louis School of Medicine, St. Louis, United States.,Needleman Center for Neurometabolism and Axonal Therapeutics, St. Louis, United States
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8
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Abstract
One in three epilepsy cases is drug resistant, and seizures often begin in infancy, when they are life-threatening and when therapeutic options are highly limited. An important tool for prioritizing and validating genes associated with epileptic conditions, which is suitable for large-scale screening, is disease modeling in Drosophila. Approximately two-thirds of disease genes are conserved in Drosophila, and gene-specific fly models exhibit behavioral changes that are related to symptoms of epilepsy. Models are based on behavior readouts, seizure-like attacks and paralysis following stimulation, and neuronal, cell-biological readouts that are in the majority based on changes in nerve cell activity or morphology. In this review, we focus on behavioral phenotypes. Importantly, Drosophila modeling is independent of, and complementary to, other approaches that are computational and based on systems analysis. The large number of known epilepsy-associated gene variants indicates a need for efficient research strategies. We will discuss the status quo of epilepsy disease modelling in Drosophila and describe promising steps towards the development of new drugs to reduce seizure rates and alleviate other epileptic symptoms.
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Affiliation(s)
- Paul Lasko
- Department of Human Genetics, Radboud University Medical Centre, Nijmegen, Netherlands
- Department of Biology, McGill University, Montréal, Québec, Canada
| | - Kevin Lüthy
- Department of Human Genetics, Radboud University Medical Centre, Nijmegen, Netherlands
- Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Centre, Nijmegen, Netherlands
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9
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Talsness DM, Owings KG, Coelho E, Mercenne G, Pleinis JM, Partha R, Hope KA, Zuberi AR, Clark NL, Lutz CM, Rodan AR, Chow CY. A Drosophila screen identifies NKCC1 as a modifier of NGLY1 deficiency. eLife 2020; 9:57831. [PMID: 33315011 PMCID: PMC7758059 DOI: 10.7554/elife.57831] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2020] [Accepted: 12/12/2020] [Indexed: 12/12/2022] Open
Abstract
N-Glycanase 1 (NGLY1) is a cytoplasmic deglycosylating enzyme. Loss-of-function mutations in the NGLY1 gene cause NGLY1 deficiency, which is characterized by developmental delay, seizures, and a lack of sweat and tears. To model the phenotypic variability observed among patients, we crossed a Drosophila model of NGLY1 deficiency onto a panel of genetically diverse strains. The resulting progeny showed a phenotypic spectrum from 0 to 100% lethality. Association analysis on the lethality phenotype, as well as an evolutionary rate covariation analysis, generated lists of modifying genes, providing insight into NGLY1 function and disease. The top association hit was Ncc69 (human NKCC1/2), a conserved ion transporter. Analyses in NGLY1-/- mouse cells demonstrated that NKCC1 has an altered average molecular weight and reduced function. The misregulation of this ion transporter may explain the observed defects in secretory epithelium function in NGLY1 deficiency patients.
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Affiliation(s)
- Dana M Talsness
- Department of Human Genetics, University of Utah School of Medicine, Salt Lake City, United States
| | - Katie G Owings
- Department of Human Genetics, University of Utah School of Medicine, Salt Lake City, United States
| | - Emily Coelho
- Department of Human Genetics, University of Utah School of Medicine, Salt Lake City, United States
| | - Gaelle Mercenne
- Department of Internal Medicine, Division of Nephrology and Hypertension, and Molecular Medicine Program, University of Utah, Salt Lake City, United States
| | - John M Pleinis
- Department of Internal Medicine, Division of Nephrology and Hypertension, and Molecular Medicine Program, University of Utah, Salt Lake City, United States
| | - Raghavendran Partha
- Department of Computational and Systems Biology, University of Pittsburgh, Pittsburgh, United States
| | - Kevin A Hope
- Department of Human Genetics, University of Utah School of Medicine, Salt Lake City, United States
| | - Aamir R Zuberi
- Genetic Resource Science, The Jackson Laboratory, Bar Harbor, United States
| | - Nathan L Clark
- Department of Human Genetics, University of Utah School of Medicine, Salt Lake City, United States
| | - Cathleen M Lutz
- Genetic Resource Science, The Jackson Laboratory, Bar Harbor, United States
| | - Aylin R Rodan
- Department of Internal Medicine, Division of Nephrology and Hypertension, and Molecular Medicine Program, University of Utah, Salt Lake City, United States.,Medical Service, Veterans Affairs Salt Lake City Health Care System, Salt Lake City, United States
| | - Clement Y Chow
- Department of Human Genetics, University of Utah School of Medicine, Salt Lake City, United States
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Wrapping glia regulates neuronal signaling speed and precision in the peripheral nervous system of Drosophila. Nat Commun 2020; 11:4491. [PMID: 32901033 PMCID: PMC7479103 DOI: 10.1038/s41467-020-18291-1] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2019] [Accepted: 08/11/2020] [Indexed: 02/06/2023] Open
Abstract
The functionality of the nervous system requires transmission of information along axons with high speed and precision. Conductance velocity depends on axonal diameter whereas signaling precision requires a block of electrical crosstalk between axons, known as ephaptic coupling. Here, we use the peripheral nervous system of Drosophila larvae to determine how glia regulates axonal properties. We show that wrapping glial differentiation depends on gap junctions and FGF-signaling. Abnormal glial differentiation affects axonal diameter and conductance velocity and causes mild behavioral phenotypes that can be rescued by a sphingosine-rich diet. Ablation of wrapping glia does not further impair axonal diameter and conductance velocity but causes a prominent locomotion phenotype that cannot be rescued by sphingosine. Moreover, optogenetically evoked locomotor patterns do not depend on conductance speed but require the presence of wrapping glial processes. In conclusion, our data indicate that wrapping glia modulates both speed and precision of neuronal signaling.
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11
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Takai A, Yamaguchi M, Yoshida H, Chiyonobu T. Investigating Developmental and Epileptic Encephalopathy Using Drosophila melanogaster. Int J Mol Sci 2020; 21:ijms21176442. [PMID: 32899411 PMCID: PMC7503973 DOI: 10.3390/ijms21176442] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2020] [Revised: 08/30/2020] [Accepted: 09/01/2020] [Indexed: 12/16/2022] Open
Abstract
Developmental and epileptic encephalopathies (DEEs) are the spectrum of severe epilepsies characterized by early-onset, refractory seizures occurring in the context of developmental regression or plateauing. Early infantile epileptic encephalopathy (EIEE) is one of the earliest forms of DEE, manifesting as frequent epileptic spasms and characteristic electroencephalogram findings in early infancy. In recent years, next-generation sequencing approaches have identified a number of monogenic determinants underlying DEE. In the case of EIEE, 85 genes have been registered in Online Mendelian Inheritance in Man as causative genes. Model organisms are indispensable tools for understanding the in vivo roles of the newly identified causative genes. In this review, we first present an overview of epilepsy and its genetic etiology, especially focusing on EIEE and then briefly summarize epilepsy research using animal and patient-derived induced pluripotent stem cell (iPSC) models. The Drosophila model, which is characterized by easy gene manipulation, a short generation time, low cost and fewer ethical restrictions when designing experiments, is optimal for understanding the genetics of DEE. We therefore highlight studies with Drosophila models for EIEE and discuss the future development of their practical use.
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Affiliation(s)
- Akari Takai
- Department of Pediatrics, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto 602-8566, Japan;
| | - Masamitsu Yamaguchi
- Department of Applied Biology, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto 603-8585, Japan; (M.Y.); (H.Y.)
- Kansai Gakken Laboratory, Kankyo Eisei Yakuhin Co. Ltd., Kyoto 619-0237, Japan
| | - Hideki Yoshida
- Department of Applied Biology, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto 603-8585, Japan; (M.Y.); (H.Y.)
| | - Tomohiro Chiyonobu
- Department of Pediatrics, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto 602-8566, Japan;
- Correspondence:
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12
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Li H, Russo A, DiAntonio A. SIK3 suppresses neuronal hyperexcitability by regulating the glial capacity to buffer K + and water. J Cell Biol 2019; 218:4017-4029. [PMID: 31645458 PMCID: PMC6891094 DOI: 10.1083/jcb.201907138] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2019] [Revised: 08/27/2019] [Accepted: 09/19/2019] [Indexed: 01/10/2023] Open
Abstract
Glial regulation of extracellular potassium (K+) helps to maintain appropriate levels of neuronal excitability. While channels and transporters mediating K+ and water transport are known, little is understood about upstream regulatory mechanisms controlling the glial capacity to buffer K+ and osmotically obliged water. Here we identify salt-inducible kinase 3 (SIK3) as the central node in a signal transduction pathway controlling glial K+ and water homeostasis in Drosophila Loss of SIK3 leads to dramatic extracellular fluid accumulation in nerves, neuronal hyperexcitability, and seizures. SIK3-dependent phenotypes are exacerbated by K+ stress. SIK3 promotes the cytosolic localization of HDAC4, thereby relieving inhibition of Mef2-dependent transcription of K+ and water transport molecules. This transcriptional program controls the glial capacity to regulate K+ and water homeostasis and modulate neuronal excitability. We identify HDAC4 as a candidate therapeutic target in this pathway, whose inhibition can enhance the K+ buffering capacity of glia, which may be useful in diseases of dysregulated K+ homeostasis and hyperexcitability.
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Affiliation(s)
- Hailun Li
- Department of Developmental Biology, Washington University in St. Louis School of Medicine, St. Louis, MO
| | - Alexandra Russo
- Department of Developmental Biology, Washington University in St. Louis School of Medicine, St. Louis, MO
| | - Aaron DiAntonio
- Department of Developmental Biology, Washington University in St. Louis School of Medicine, St. Louis, MO
- Needleman Center for Neurometabolism and Axonal Therapeutics, Washington University in St. Louis School of Medicine, St. Louis, MO
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13
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Hill AS, Jain P, Folan NE, Ben-Shahar Y. The Drosophila ERG channel seizure plays a role in the neuronal homeostatic stress response. PLoS Genet 2019; 15:e1008288. [PMID: 31393878 PMCID: PMC6687100 DOI: 10.1371/journal.pgen.1008288] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2019] [Accepted: 07/04/2019] [Indexed: 11/24/2022] Open
Abstract
Neuronal physiology is particularly sensitive to acute stressors that affect excitability, many of which can trigger seizures and epilepsies. Although intrinsic neuronal homeostasis plays an important role in maintaining overall nervous system robustness and its resistance to stressors, the specific genetic and molecular mechanisms that underlie these processes are not well understood. Here we used a reverse genetic approach in Drosophila to test the hypothesis that specific voltage-gated ion channels contribute to neuronal homeostasis, robustness, and stress resistance. We found that the activity of the voltage-gated potassium channel seizure (sei), an ortholog of the mammalian ERG channel family, is essential for protecting flies from acute heat-induced seizures. Although sei is broadly expressed in the nervous system, our data indicate that its impact on the organismal robustness to acute environmental stress is primarily mediated via its action in excitatory neurons, the octopaminergic system, as well as neuropile ensheathing and perineurial glia. Furthermore, our studies suggest that human mutations in the human ERG channel (hERG), which have been primarily implicated in the cardiac Long QT Syndrome (LQTS), may also contribute to the high incidence of seizures in LQTS patients via a cardiovascular-independent neurogenic pathway.
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Affiliation(s)
- Alexis S. Hill
- Department of Biology, College of the Holy Cross, Worcester, Massachusetts, United States of America
| | - Poorva Jain
- Department of Biology, Washington University in St. Louis, St. Louis, Missouri, United States of America
| | - Nicole E. Folan
- Department of Biology, College of the Holy Cross, Worcester, Massachusetts, United States of America
| | - Yehuda Ben-Shahar
- Department of Biology, Washington University in St. Louis, St. Louis, Missouri, United States of America
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14
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Chen R, Prael FJ, Li Z, Delpire E, Weaver CD, Swale DR. Functional Coupling of K +-Cl - Cotransporter (KCC) to GABA-Gated Cl - Channels in the Central Nervous System of Drosophila melanogaster Leads to Altered Drug Sensitivities. ACS Chem Neurosci 2019; 10:2765-2776. [PMID: 30942574 DOI: 10.1021/acschemneuro.8b00697] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
GABAergic signaling is the cornerstone for fast synaptic inhibition of neural signaling in arthropods and mammals and is the molecular target for insecticides and pharmaceuticals, respectively. The K+-Cl- cotransporter (KCC) is the primary mechanism by which mature neurons maintain low intracellular Cl- concentration, yet the fundamental physiology, comparative physiology, and toxicological relevance of insect KCC is understudied. Considering this, we employed electrophysiological, genetic, and pharmacological methods to characterize the physiological underpinnings of KCC function to the Drosophila CNS. Our data show that genetic ablation or pharmacological inhibition of KCC results in an increased spike discharge frequency and significantly ( P < 0.05) reduces the CNS sensitivity to γ-aminobutyric acid (GABA). Further, simultaneous inhibition of KCC and ligand-gated chloride channel (LGCC) complex results in a significant ( P < 0.001) increase in CNS spontaneous activity over baseline firing rates that supports functional coupling of KCC to LGCC function. Interestingly, 75% reduction in KCC mRNA did not alter basal neurotransmission levels indicating that only a fraction of the KCC population is required to maintain the Cl- ionic gradient when at rest, but prolonged synaptic activity increases the threshold for GABA-mediated inhibition and reduces nerve sensitivity to GABA. These data expand current knowledge regarding the physiological role of KCC in a model insect and provides the necessary foundation to develop KCC as a novel biochemical target of insecticides, as well as complements existing research to provide a holistic understanding of the plasticity in mammalian health and disease.
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Affiliation(s)
- Rui Chen
- Department of Entomology , Louisiana State University AgCenter , Baton Rouge , Louisiana 70803 , United States
| | - Francis J Prael
- Department of Pharmacology , Vanderbilt University , Nashville , Tennessee 37232 , United States
- Vanderbilt Institute of Chemical Biology , Vanderbilt University , Nashville , Tennessee 37232 , United States
| | - Zhilin Li
- Department of Entomology , Louisiana State University AgCenter , Baton Rouge , Louisiana 70803 , United States
| | - Eric Delpire
- Department of Anesthesiology , Vanderbilt University School of Medicine , Nashville , Tennessee 37232 , United States
| | - C David Weaver
- Department of Pharmacology , Vanderbilt University , Nashville , Tennessee 37232 , United States
- Vanderbilt Institute of Chemical Biology , Vanderbilt University , Nashville , Tennessee 37232 , United States
| | - Daniel R Swale
- Department of Entomology , Louisiana State University AgCenter , Baton Rouge , Louisiana 70803 , United States
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15
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Abstract
Glia are abundant components of animal nervous systems. Recognized 170 years ago, concerted attempts to understand these cells began only recently. From these investigations glia, once considered passive filler material in the brain, have emerged as active players in neuron development and activity. Glia are essential for nervous system function, and their disruption leads to disease. The nematode Caenorhabditis elegans possesses glial types similar to vertebrate glia, based on molecular, morphological, and functional criteria, and has become a powerful model in which to study glia and their neuronal interactions. Facile genetic and transgenic methods in this animal allow the discovery of genes required for glial functions, and effects of glia at single synapses can be monitored by tracking neuron shape, physiology, or animal behavior. Here, we review recent progress in understanding glia-neuron interactions in C. elegans. We highlight similarities with glia in other animals, and suggest conserved emerging principles of glial function.
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Affiliation(s)
- Aakanksha Singhvi
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, Washington 98109, USA;
| | - Shai Shaham
- Laboratory of Developmental Genetics, The Rockefeller University, New York, NY 10065, USA;
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16
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Stenesen D, Moehlman AT, Schellinger JN, Rodan AR, Krämer H. The glial sodium-potassium-2-chloride cotransporter is required for synaptic transmission in the Drosophila visual system. Sci Rep 2019; 9:2475. [PMID: 30792494 PMCID: PMC6385505 DOI: 10.1038/s41598-019-38850-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2018] [Accepted: 01/08/2019] [Indexed: 02/07/2023] Open
Abstract
The Drosophila Ncc69 gene encodes a Na+-K+-2Cl−-cotransporter (NKCC) that is critical for regulating intra- and extracellular ionic conditions in different tissues. Here, we show that the Ncc69 transporter is necessary for fly vision and that its expression is required non-autonomously in glia to maintain visual synaptic transmission. Flies mutant for Ncc69 exhibit normal photoreceptor depolarization in response to a light pulse but lack the ON and OFF-transients characteristic of postsynaptic responses of lamina neurons, indicating a failure in synaptic transmission. We also find that synaptic transmission requires the Ncc69 regulatory kinases WNK and Fray in glia. The ERG phenotype is associated with a defect in the recycling of the histamine neurotransmitter. Ncc69 mutants exhibit higher levels of the transport metabolite carcinine in lamina cartridges, with its accumulation most intense in the extracellular space. Our work reveals a novel role of glial NKCC transporters in synaptic transmission, possibly through regulating extracellular ionic conditions.
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Affiliation(s)
- Drew Stenesen
- Department of Neuroscience, University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA.,Biology Department, University of Dallas, Irving, TX, 75062, USA
| | - Andrew T Moehlman
- Department of Neuroscience, University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA
| | - Jeffrey N Schellinger
- Department of Internal Medicine, Division of Nephrology, University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA
| | - Aylin R Rodan
- Department of Internal Medicine, Division of Nephrology, University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA. .,Department of Internal Medicine, Division of Nephrology and Hypertension and Molecular Medicine Program, University of Utah, Salt Lake City, UT, 84112, USA. .,Medical Service, Veterans Affairs Salt Lake City Health Care System, Salt Lake City, Utah, USA.
| | - Helmut Krämer
- Department of Neuroscience, University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA. .,Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA.
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17
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Investigation of Seizure-Susceptibility in a Drosophila melanogaster Model of Human Epilepsy with Optogenetic Stimulation. Genetics 2017. [PMID: 28630111 DOI: 10.1534/genetics.116.194779] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
We examined seizure-susceptibility in a Drosophila model of human epilepsy using optogenetic stimulation of ReaChR (red-activatable channelrhodopsin). Photostimulation of the seizure-sensitive mutant parabss1 causes behavioral paralysis that resembles paralysis caused by mechanical stimulation, in many aspects. Electrophysiology shows that photostimulation evokes abnormal seizure-like neuronal firing in parabss1 followed by a quiescent period resembling synaptic failure and apparently responsible for paralysis. The pattern of neuronal activity concludes with seizure-like activity just prior to recovery. We tentatively identify the mushroom body as one apparent locus of optogenetic seizure initiation. The α/β lobes may be primarily responsible for mushroom body seizure induction.
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18
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Ng FS, Sengupta S, Huang Y, Yu AM, You S, Roberts MA, Iyer LK, Yang Y, Jackson FR. TRAP-seq Profiling and RNAi-Based Genetic Screens Identify Conserved Glial Genes Required for Adult Drosophila Behavior. Front Mol Neurosci 2016; 9:146. [PMID: 28066175 PMCID: PMC5177635 DOI: 10.3389/fnmol.2016.00146] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2016] [Accepted: 11/30/2016] [Indexed: 01/06/2023] Open
Abstract
Although, glial cells have well characterized functions in the developing and mature brain, it is only in the past decade that roles for these cells in behavior and plasticity have been delineated. Glial astrocytes and glia-neuron signaling, for example, are now known to have important modulatory functions in sleep, circadian behavior, memory and plasticity. To better understand mechanisms of glia-neuron signaling in the context of behavior, we have conducted cell-specific, genome-wide expression profiling of adult Drosophila astrocyte-like brain cells and performed RNA interference (RNAi)-based genetic screens to identify glial factors that regulate behavior. Importantly, our studies demonstrate that adult fly astrocyte-like cells and mouse astrocytes have similar molecular signatures; in contrast, fly astrocytes and surface glia-different classes of glial cells-have distinct expression profiles. Glial-specific expression of 653 RNAi constructs targeting 318 genes identified multiple factors associated with altered locomotor activity, circadian rhythmicity and/or responses to mechanical stress (bang sensitivity). Of interest, 1 of the relevant genes encodes a vesicle recycling factor, 4 encode secreted proteins and 3 encode membrane transporters. These results strongly support the idea that glia-neuron communication is vital for adult behavior.
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Affiliation(s)
- Fanny S Ng
- Department of Neuroscience, Sackler Program in Biomedical Sciences, Tufts University School of Medicine Boston, MA, USA
| | - Sukanya Sengupta
- Department of Neuroscience, Sackler Program in Biomedical Sciences, Tufts University School of Medicine Boston, MA, USA
| | - Yanmei Huang
- Department of Neuroscience, Sackler Program in Biomedical Sciences, Tufts University School of Medicine Boston, MA, USA
| | - Amy M Yu
- Department of Neuroscience, Sackler Program in Biomedical Sciences, Tufts University School of Medicine Boston, MA, USA
| | - Samantha You
- Department of Neuroscience, Sackler Program in Biomedical Sciences, Tufts University School of Medicine Boston, MA, USA
| | - Mary A Roberts
- Department of Neuroscience, Sackler Program in Biomedical Sciences, Tufts University School of Medicine Boston, MA, USA
| | - Lakshmanan K Iyer
- Department of Neuroscience, Sackler Program in Biomedical Sciences, Tufts University School of Medicine Boston, MA, USA
| | - Yongjie Yang
- Department of Neuroscience, Sackler Program in Biomedical Sciences, Tufts University School of Medicine Boston, MA, USA
| | - F Rob Jackson
- Department of Neuroscience, Sackler Program in Biomedical Sciences, Tufts University School of Medicine Boston, MA, USA
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19
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Yoshida A, Nakano S, Suzuki T, Ihara K, Higashiyama T, Mori I. A glial K(+) /Cl(-) cotransporter modifies temperature-evoked dynamics in Caenorhabditis elegans sensory neurons. GENES, BRAIN, AND BEHAVIOR 2016; 15:429-40. [PMID: 26463820 DOI: 10.1111/gbb.12260] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/15/2015] [Revised: 09/30/2015] [Accepted: 10/08/2015] [Indexed: 11/30/2022]
Abstract
K(+) /Cl(-) cotransporters (KCCs) are known to be crucial in the control of neuronal electrochemical Cl(-) gradient. However, the role of these proteins in glial cells remains largely unexplored despite a number of studies showing expression of KCC proteins in glial cells of many species. Here, we show that the Caenorhabditis elegans K(+) /Cl(-) cotransporter KCC-3 is expressed in glial-like cells and regulates the thermosensory behavior through modifying temperature-evoked activity of a thermosensory neuron. Mutations in the kcc-3 gene were isolated from a genetic screen for mutants defective in thermotaxis. KCC-3 is expressed and functions in the amphid sheath glia that ensheathes the AFD neuron, a major thermosensory neuron known to be required for thermotaxis. A genetic analysis indicated that the regulation of the thermosensory behavior by KCC-3 is mediated through AFD, and we further show that KCC-3 in the amphid sheath glia regulates the dynamics of the AFD activity. Our results show a novel mechanism by which the glial KCC-3 protein non-cell autonomously modifies the stimulus-evoked activity of a sensory neuron and highlights the functional importance of glial KCC proteins in modulating the dynamics of a neural circuitry to control an animal behavior.
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Affiliation(s)
- A Yoshida
- Division of Biological Science, Graduate School of Science, Nagoya University, Nagoya, Aichi, Japan
| | - S Nakano
- Division of Biological Science, Graduate School of Science, Nagoya University, Nagoya, Aichi, Japan
| | - T Suzuki
- Division of Biological Science, Graduate School of Science, Nagoya University, Nagoya, Aichi, Japan
- JST ERATO Higashiyama Live-Holonics Project, Nagoya University, Nagoya, Aichi, Japan
- Present address: College of Bioscience and Biotechnology, Chubu University, Kasugai, Aichi, Japan
| | - K Ihara
- Center for Gene Research, Nagoya University, Nagoya, Aichi, Japan
| | - T Higashiyama
- Division of Biological Science, Graduate School of Science, Nagoya University, Nagoya, Aichi, Japan
- JST ERATO Higashiyama Live-Holonics Project, Nagoya University, Nagoya, Aichi, Japan
- Institute of Transformative Bio-Molecules (ITbM), Nagoya University, Nagoya, Aichi, Japan
| | - I Mori
- Division of Biological Science, Graduate School of Science, Nagoya University, Nagoya, Aichi, Japan
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20
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Disruption of Endocytosis with the Dynamin Mutant shibirets1 Suppresses Seizures in Drosophila. Genetics 2015; 201:1087-102. [PMID: 26341658 DOI: 10.1534/genetics.115.177600] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2015] [Accepted: 08/31/2015] [Indexed: 11/18/2022] Open
Abstract
One challenge in modern medicine is to control epilepsies that do not respond to currently available medications. Since seizures consist of coordinated and high-frequency neural activity, our goal was to disrupt neurotransmission with a synaptic transmission mutant and evaluate its ability to suppress seizures. We found that the mutant shibire, encoding dynamin, suppresses seizure-like activity in multiple seizure-sensitive Drosophila genotypes, one of which resembles human intractable epilepsy in several aspects. Because of the requirement of dynamin in endocytosis, increased temperature in the shi(ts1) mutant causes impairment of synaptic vesicle recycling and is associated with suppression of the seizure-like activity. Additionally, we identified the giant fiber neuron as critical in the seizure circuit and sufficient to suppress seizures. Overall, our results implicate mutant dynamin as an effective seizure suppressor, suggesting that targeting or limiting the availability of synaptic vesicles could be an effective and general method of controlling epilepsy disorders.
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21
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Kahle KT, Khanna AR, Alper SL, Adragna NC, Lauf PK, Sun D, Delpire E. K-Cl cotransporters, cell volume homeostasis, and neurological disease. Trends Mol Med 2015; 21:513-23. [PMID: 26142773 PMCID: PMC4834970 DOI: 10.1016/j.molmed.2015.05.008] [Citation(s) in RCA: 87] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2015] [Revised: 05/10/2015] [Accepted: 05/29/2015] [Indexed: 11/24/2022]
Abstract
K(+)-Cl(-) cotransporters (KCCs) were originally characterized as regulators of red blood cell (RBC) volume. Since then, four distinct KCCs have been cloned, and their importance for volume regulation has been demonstrated in other cell types. Genetic models of certain KCCs, such as KCC3, and their inhibitory WNK-STE20/SPS1-related proline/alanine-rich kinase (SPAK) serine-threonine kinases, have demonstrated the evolutionary necessity of these molecules for nervous system cell volume regulation, structure, and function, and their involvement in neurological disease. The recent characterization of a swelling-activated dephosphorylation mechanism that potently stimulates the KCCs has pinpointed a potentially druggable switch of KCC activity. An improved understanding of WNK/SPAK-mediated KCC cell volume regulation in the nervous system might reveal novel avenues for the treatment of multiple neurological diseases.
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Affiliation(s)
- Kristopher T Kahle
- Department of Neurosurgery, Boston Children's Hospital and Harvard Medical School, Boston, MA 02114, USA; Manton Center for Orphan Disease Research, Children's Hospital Boston, 300 Longwood Avenue, Boston, MA 02114, USA.
| | - Arjun R Khanna
- Department of Neurosurgery, Boston Children's Hospital and Harvard Medical School, Boston, MA 02114, USA
| | - Seth L Alper
- Renal Division and Molecular and Vascular Medicine Division, Beth Israel Deaconess Medical Center; Department of Medicine, Harvard Medical School, Boston, MA 02215, USA
| | - Norma C Adragna
- Department of Pharmacology and Toxicology, Boonshoft School of Medicine, Wright State University, Dayton, OH 45435, USA
| | - Peter K Lauf
- Department of Pharmacology and Toxicology, Boonshoft School of Medicine, Wright State University, Dayton, OH 45435, USA; Department of Pathology, Boonshoft School of Medicine, Wright State University, Dayton, OH 45435, USA
| | - Dandan Sun
- Department of Neurology, University of Pittsburgh, Pittsburgh, PA 15217, USA; Veterans Affairs Pittsburgh Health Care System, Geriatric Research, Educational and Clinical Center, Pittsburgh, PA 15213, USA
| | - Eric Delpire
- Department of Anesthesiology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA.
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22
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Kroll JR, Saras A, Tanouye MA. Drosophila sodium channel mutations: Contributions to seizure-susceptibility. Exp Neurol 2015; 274:80-7. [PMID: 26093037 DOI: 10.1016/j.expneurol.2015.06.018] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2014] [Revised: 06/14/2015] [Accepted: 06/16/2015] [Indexed: 01/10/2023]
Abstract
This paper reviews Drosophila voltage-gated Na(+) channel mutations encoded by the para (paralytic) gene and their contributions to seizure disorders in the fly. Numerous mutations cause seizure-sensitivity, for example, para(bss1), with phenotypes that resemble human intractable epilepsy in some aspects. Seizure phenotypes are also seen with human GEFS+ spectrum mutations that have been knocked into the Drosophila para gene, para(GEFS+) and para(DS) alleles. Other para mutations, para(ST76) and para(JS) act as seizure-suppressor mutations reverting seizure phenotypes in other mutants. Seizure-like phenotypes are observed from mutations and other conditions that cause a persistent Na(+) current through either changes in mRNA splicing or protein structure.
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Affiliation(s)
- Jason R Kroll
- Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720, USA
| | - Arunesh Saras
- Department of Environmental Science, Policy and Management, University of California, Berkeley, CA 94720, USA
| | - Mark A Tanouye
- Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720, USA; Department of Environmental Science, Policy and Management, University of California, Berkeley, CA 94720, USA.
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23
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Musto AE, Walker CP, Petasis NA, Bazan NG. Hippocampal neuro-networks and dendritic spine perturbations in epileptogenesis are attenuated by neuroprotectin d1. PLoS One 2015; 10:e0116543. [PMID: 25617763 PMCID: PMC4305283 DOI: 10.1371/journal.pone.0116543] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2014] [Accepted: 12/10/2014] [Indexed: 12/11/2022] Open
Abstract
Purpose Limbic epileptogenesis triggers molecular and cellular events that foster the establishment of aberrant neuronal networks that, in turn, contribute to temporal lobe epilepsy (TLE). Here we have examined hippocampal neuronal network activities in the pilocarpine post-status epilepticus model of limbic epileptogenesis and asked whether or not the docosahexaenoic acid (DHA)-derived lipid mediator, neuroprotectin D1 (NPD1), modulates epileptogenesis. Methods Status epilepticus (SE) was induced by intraperitoneal administration of pilocarpine in adult male C57BL/6 mice. To evaluate simultaneous hippocampal neuronal networks, local field potentials were recorded from multi-microelectrode arrays (silicon probe) chronically implanted in the dorsal hippocampus. NPD1 (570 μg/kg) or vehicle was administered intraperitoneally daily for five consecutive days 24 hours after termination of SE. Seizures and epileptiform activity were analyzed in freely-moving control and treated mice during epileptogenesis and epileptic periods. Then hippocampal dendritic spines were evaluated using Golgi-staining. Results We found brief spontaneous microepileptiform activity with high amplitudes in the CA1 pyramidal and stratum radiatum in epileptogenesis. These aberrant activities were attenuated following systemic NPD1 administration, with concomitant hippocampal dendritic spine protection. Moreover, NPD1 treatment led to a reduction in spontaneous recurrent seizures. Conclusions Our results indicate that NPD1 displays neuroprotective bioactivity on the hippocampal neuronal network ensemble that mediates aberrant circuit activity during epileptogenesis. Insight into the molecular signaling mediated by neuroprotective bioactivity of NPD1 on neuronal network dysfunction may contribute to the development of anti-epileptogenic therapeutic strategies.
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Affiliation(s)
- Alberto E. Musto
- Neuroscience Center of Excellence, Louisiana State University Health Sciences Center, New Orleans, Louisiana, United States of America
- * E-mail: (NGB); (AEM)
| | - Chelsey P. Walker
- Neuroscience Center of Excellence, Louisiana State University Health Sciences Center, New Orleans, Louisiana, United States of America
| | - Nicos A. Petasis
- Department of Chemistry, Loker Hydrocarbon Research Institute, University of Southern California, Los Angeles, California, United States of America
| | - Nicolas G. Bazan
- Neuroscience Center of Excellence, Louisiana State University Health Sciences Center, New Orleans, Louisiana, United States of America
- * E-mail: (NGB); (AEM)
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24
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Abstract
Brain glial cells, in particular astrocytes and microglia, secrete signaling molecules that regulate glia-glia or glia-neuron communication and synaptic activity. While much is known about roles of glial cells in nervous system development, we are only beginning to understand the physiological functions of such cells in the adult brain. Studies in vertebrate and invertebrate models, in particular mice and Drosophila, have revealed roles of glia-neuron communication in the modulation of complex behavior. This chapter emphasizes recent evidence from studies of rodents and Drosophila that highlight the importance of glial cells and similarities or differences in the neural circuits regulating circadian rhythms and sleep in the two models. The chapter discusses cellular, molecular, and genetic approaches that have been useful in these models for understanding how glia-neuron communication contributes to the regulation of rhythmic behavior.
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Affiliation(s)
- F Rob Jackson
- Department of Neuroscience, Sackler Program in Biomedical Sciences, Tufts University School of Medicine, Boston, MA, USA.
| | - Fanny S Ng
- Department of Neuroscience, Sackler Program in Biomedical Sciences, Tufts University School of Medicine, Boston, MA, USA
| | - Sukanya Sengupta
- Department of Neuroscience, Sackler Program in Biomedical Sciences, Tufts University School of Medicine, Boston, MA, USA
| | - Samantha You
- Department of Neuroscience, Sackler Program in Biomedical Sciences, Tufts University School of Medicine, Boston, MA, USA
| | - Yanmei Huang
- Department of Neuroscience, Sackler Program in Biomedical Sciences, Tufts University School of Medicine, Boston, MA, USA
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