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Wasilewicz LJ, Gagnon ZE, Jung J, Mercier AJ. Investigating postsynaptic effects of a Drosophila neuropeptide on muscle contraction. J Neurophysiol 2024; 131:137-151. [PMID: 38150542 DOI: 10.1152/jn.00246.2023] [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: 06/20/2023] [Revised: 11/20/2023] [Accepted: 12/20/2023] [Indexed: 12/29/2023] Open
Abstract
The Drosophila neuropeptide, DPKQDFMRFamide, was previously shown to enhance excitatory junctional potentials (EJPs) and muscle contraction by both presynaptic and postsynaptic actions. Since the peptide acts on both sides of the synaptic cleft, it has been difficult to examine postsynaptic modulatory mechanisms, particularly when contractions are elicited by nerve stimulation. Here, postsynaptic actions are examined in 3rd instar larvae by applying peptide and the excitatory neurotransmitter, l-glutamate, in the bathing solution to elicit contractions after silencing motor output by removing the central nervous system (CNS). DPKQDFMRFamide enhanced glutamate-evoked contractions at low concentrations (EC50 1.3 nM), consistent with its role as a neurohormone, and the combined effect of both substances was supra-additive. Glutamate-evoked contractions were also enhanced when transmitter release was blocked in temperature-sensitive (Shibire) mutants, confirming the peptide's postsynaptic action. The peptide increased membrane depolarization in muscle when co-applied with glutamate, and its effects were blocked by nifedipine, an L-type channel blocker, indicating effects at the plasma membrane involving calcium influx. DPKQDFMRFamide also enhanced contractions induced by caffeine in the absence of extracellular calcium, suggesting increased calcium release from the sarcoplasmic reticulum (SR) or effects downstream of calcium release from the SR. The peptide's effects do not appear to involve calcium/calmodulin-dependent protein kinase II (CaMKII), previously shown to mediate presynaptic effects. The approach used here might be useful for examining postsynaptic effects of neurohormones and cotransmitters in other systems.NEW & NOTEWORTHY Distinguishing presynaptic and postsynaptic effects of neurohormones is a long-standing challenge in many model organisms. Here, postsynaptic actions of DPKQDFMRFamide are demonstrated by assessing its ability to potentiate contractions elicited by direct application of the neurotransmitter, glutamate, when axons are silent and when transmitter release is blocked. The peptide acts at multiple sites to increase contraction, increasing glutamate-induced depolarization at the cell membrane, acting on L-type channels, and acting downstream of calcium release from the sarcoplasmic reticulum.
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Affiliation(s)
- Lucas J Wasilewicz
- Department of Biological Sciences, Brock University, St. Catharines, Ontario, Canada
| | - Zoe E Gagnon
- Department of Biological Sciences, Brock University, St. Catharines, Ontario, Canada
| | - JaeHwan Jung
- Department of Biological Sciences, Brock University, St. Catharines, Ontario, Canada
| | - A Joffre Mercier
- Department of Biological Sciences, Brock University, St. Catharines, Ontario, Canada
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Stege NM, Eijgenraam TR, Oliveira Nunes Teixeira V, Feringa AM, Schouten EM, Kuster DW, van der Velden J, Wolters AH, Giepmans BN, Makarewich CA, Bassel-Duby R, Olson EN, de Boer RA, Silljé HH. DWORF Extends Life Span in a PLN-R14del Cardiomyopathy Mouse Model by Reducing Abnormal Sarcoplasmic Reticulum Clusters. Circ Res 2023; 133:1006-1021. [PMID: 37955153 PMCID: PMC10699510 DOI: 10.1161/circresaha.123.323304] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/30/2023] [Revised: 10/18/2023] [Accepted: 11/01/2023] [Indexed: 11/14/2023]
Abstract
BACKGROUND The p.Arg14del variant of the PLN (phospholamban) gene causes cardiomyopathy, leading to severe heart failure. Calcium handling defects and perinuclear PLN aggregation have both been suggested as pathological drivers of this disease. Dwarf open reading frame (DWORF) has been shown to counteract PLN regulatory calcium handling function in the sarco/endoplasmic reticulum (S/ER). Here, we investigated the potential disease-modulating action of DWORF in this cardiomyopathy and its effects on calcium handling and PLN aggregation. METHODS We studied a PLN-R14del mouse model, which develops cardiomyopathy with similar characteristics as human patients, and explored whether cardiac DWORF overexpression could delay cardiac deterioration. To this end, R14Δ/Δ (homozygous PLN-R14del) mice carrying the DWORF transgene (R14Δ/ΔDWORFTg [R14Δ/Δ mice carrying the DWORF transgene]) were used. RESULTS DWORF expression was suppressed in hearts of R14Δ/Δ mice with severe heart failure. Restoration of DWORF expression in R14Δ/Δ mice delayed cardiac fibrosis and heart failure and increased life span >2-fold (from 8 to 18 weeks). DWORF accelerated sarcoplasmic reticulum calcium reuptake and relaxation in isolated cardiomyocytes with wild-type PLN, but in R14Δ/Δ cardiomyocytes, sarcoplasmic reticulum calcium reuptake and relaxation were already enhanced, and no differences were detected between R14Δ/Δ and R14Δ/ΔDWORFTg. Rather, DWORF overexpression delayed the appearance and formation of large pathogenic perinuclear PLN clusters. Careful examination revealed colocalization of sarcoplasmic reticulum markers with these PLN clusters in both R14Δ/Δ mice and human p.Arg14del PLN heart tissue, and hence these previously termed aggregates are comprised of abnormal organized S/ER. This abnormal S/ER organization in PLN-R14del cardiomyopathy contributes to cardiomyocyte cell loss and replacement fibrosis, consequently resulting in cardiac dysfunction. CONCLUSIONS Disorganized S/ER is a major characteristic of PLN-R14del cardiomyopathy in humans and mice and results in cardiomyocyte death. DWORF overexpression delayed PLN-R14del cardiomyopathy progression and extended life span in R14Δ/Δ mice, by reducing abnormal S/ER clusters.
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Affiliation(s)
- Nienke M. Stege
- Department of Cardiology, University Medical Center Groningen, University of Groningen, the Netherlands (N.M.S., T.R.E., V.O.N.T., A.M.F., E.M.S., R.A.d.B., H.H.W.S.)
| | - Tim R. Eijgenraam
- Department of Cardiology, University Medical Center Groningen, University of Groningen, the Netherlands (N.M.S., T.R.E., V.O.N.T., A.M.F., E.M.S., R.A.d.B., H.H.W.S.)
| | - Vivian Oliveira Nunes Teixeira
- Department of Cardiology, University Medical Center Groningen, University of Groningen, the Netherlands (N.M.S., T.R.E., V.O.N.T., A.M.F., E.M.S., R.A.d.B., H.H.W.S.)
| | - Anna M. Feringa
- Department of Cardiology, University Medical Center Groningen, University of Groningen, the Netherlands (N.M.S., T.R.E., V.O.N.T., A.M.F., E.M.S., R.A.d.B., H.H.W.S.)
| | - Elisabeth M. Schouten
- Department of Cardiology, University Medical Center Groningen, University of Groningen, the Netherlands (N.M.S., T.R.E., V.O.N.T., A.M.F., E.M.S., R.A.d.B., H.H.W.S.)
| | - Diederik W.D. Kuster
- Department of Physiology (D.W.D.K., J.v.d.V.), Amsterdam UMC, Vrije Universiteit Amsterdam, the Netherlands
- Amsterdam Cardiovascular Sciences, Heart Failure and Arrhythmias (D.W.D.K., J.v.d.V.), Amsterdam UMC, Vrije Universiteit Amsterdam, the Netherlands
| | - Jolanda van der Velden
- Department of Physiology (D.W.D.K., J.v.d.V.), Amsterdam UMC, Vrije Universiteit Amsterdam, the Netherlands
- Amsterdam Cardiovascular Sciences, Heart Failure and Arrhythmias (D.W.D.K., J.v.d.V.), Amsterdam UMC, Vrije Universiteit Amsterdam, the Netherlands
| | - Anouk H.G. Wolters
- Biomedical Sciences of Cells and Systems, UMC Groningen, University of Groningen, the Netherlands (A.H.G.W., B.N.G.G.)
| | - Ben N.G. Giepmans
- Biomedical Sciences of Cells and Systems, UMC Groningen, University of Groningen, the Netherlands (A.H.G.W., B.N.G.G.)
| | - Catherine A. Makarewich
- Division of Molecular Cardiovascular Biology of the Heart Institute, Cincinnati Children’s Hospital Medical Center, OH (C.A.M.)
- Department of Pediatrics, University of Cincinnati College of Medicine, OH (C.A.M.)
| | - Rhonda Bassel-Duby
- Department of Cardiology, University Medical Center Groningen, University of Groningen, the Netherlands (N.M.S., T.R.E., V.O.N.T., A.M.F., E.M.S., R.A.d.B., H.H.W.S.)
- Department of Molecular Biology and Hamon Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas (R.B.-D., E.N.O.)
| | - Eric N. Olson
- Department of Molecular Biology and Hamon Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas (R.B.-D., E.N.O.)
| | - Rudolf A. de Boer
- Department of Cardiology, Erasmus University Medical Center, Rotterdam, the Netherlands (R.A.d.B.)
| | - Herman H.W. Silljé
- Department of Cardiology, University Medical Center Groningen, University of Groningen, the Netherlands (N.M.S., T.R.E., V.O.N.T., A.M.F., E.M.S., R.A.d.B., H.H.W.S.)
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Buhr A, Schiemann R, Meyer H. Neprilysin 4: an essential peptidase with multifaceted physiological relevance. Biol Chem 2023; 404:513-520. [PMID: 36653344 DOI: 10.1515/hsz-2022-0286] [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: 09/22/2022] [Accepted: 12/27/2022] [Indexed: 01/20/2023]
Abstract
Neprilysins are highly conserved ectoenzymes that hydrolyze and thus inactivate signaling peptides in the extracellular space. Herein, we focus on Neprilysin 4 from Drosophila melanogaster and evaluate the existing knowledge on the physiological relevance of the peptidase. Particular attention is paid to the role of the neprilysin in regulating feeding behavior and the expression of insulin-like peptides in the central nervous system. In addition, we assess the function of the peptidase in controlling the activity of the sarcoplasmic and endoplasmic reticulum Ca2+ ATPase in myocytes, as well as the underlying molecular mechanism in detail.
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Affiliation(s)
- Annika Buhr
- Department of Biology/Chemistry, Zoology and Developmental Biology Section, Osnabruck University, Barbarastrasse 11, D-49076 Osnabruck, Germany
| | - Ronja Schiemann
- Department of Biology/Chemistry, Zoology and Developmental Biology Section, Osnabruck University, Barbarastrasse 11, D-49076 Osnabruck, Germany
| | - Heiko Meyer
- Department of Biology/Chemistry, Zoology and Developmental Biology Section, Osnabruck University, Barbarastrasse 11, D-49076 Osnabruck, Germany.,Center for Cellular Nanoanalytics (CellNanOs), Barbarastrasse 11, D-49076 Osnabruck, Germany
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Phillips TA, Robia SL. Regulation of the regulator: Endopeptidase cleavage controls the expression of a micropeptide that regulates SERCA. Cell Calcium 2022; 107:102655. [PMID: 36179466 DOI: 10.1016/j.ceca.2022.102655] [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: 08/31/2022] [Accepted: 09/20/2022] [Indexed: 11/16/2022]
Abstract
Micropeptides regulate cellular calcium handling by modulating the function of the calcium transporter SERCA. In a recent Nature Communications paper [4] authors Schiemann et al. describe regulation of an invertebrate SERCA-active micropeptide, sarcolamban, by an endopeptidase called neprilysin 4 (NEP4). NEP4 activity limits sarcolamban expression by cleavage of luminal residues near the micropeptide's c-terminus. This cleavage event liberates sarcolamban from the membrane, reduces its oligomerization, and prevents it from inhibiting SERCA. The study reveals a novel mechanism for "regulation of the regulator" that may be a general feature of micropeptide/SERCA physiology.
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Affiliation(s)
- Taylor A Phillips
- Department of Cell and Molecular Physiology, Loyola University Chicago, Maywood 60153, IL, United States of America
| | - Seth L Robia
- Department of Cell and Molecular Physiology, Loyola University Chicago, Maywood 60153, IL, United States of America.
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