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Fuchs J, Bareesel S, Kroon C, Polyzou A, Eickholt BJ, Leondaritis G. Plasma membrane phospholipid phosphatase-related proteins as pleiotropic regulators of neuron growth and excitability. Front Mol Neurosci 2022; 15:984655. [PMID: 36187351 PMCID: PMC9520309 DOI: 10.3389/fnmol.2022.984655] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2022] [Accepted: 08/23/2022] [Indexed: 11/22/2022] Open
Abstract
Neuronal plasma membrane proteins are essential for integrating cell extrinsic and cell intrinsic signals to orchestrate neuronal differentiation, growth and plasticity in the developing and adult nervous system. Here, we shed light on the family of plasma membrane proteins phospholipid phosphatase-related proteins (PLPPRs) (alternative name, PRGs; plasticity-related genes) that fine-tune neuronal growth and synaptic transmission in the central nervous system. Several studies uncovered essential functions of PLPPRs in filopodia formation, axon guidance and branching during nervous system development and regeneration, as well as in the control of dendritic spine number and excitability. Loss of PLPPR expression in knockout mice increases susceptibility to seizures, and results in defects in sensory information processing, development of psychiatric disorders, stress-related behaviors and abnormal social interaction. However, the exact function of PLPPRs in the context of neurological diseases is largely unclear. Although initially described as active lysophosphatidic acid (LPA) ecto-phosphatases that regulate the levels of this extracellular bioactive lipid, PLPPRs lack catalytic activity against LPA. Nevertheless, they emerge as atypical LPA modulators, by regulating LPA mediated signaling processes. In this review, we summarize the effects of this protein family on cellular morphology, generation and maintenance of cellular protrusions as well as highlight their known neuronal functions and phenotypes of KO mice. We discuss the molecular mechanisms of PLPPRs including the deployment of phospholipids, actin-cytoskeleton and small GTPase signaling pathways, with a focus on identifying gaps in our knowledge to stimulate interest in this understudied protein family.
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Affiliation(s)
- Joachim Fuchs
- Institute of Molecular Biology and Biochemistry, Charité – Universitätsmedizin Berlin, Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Shannon Bareesel
- Institute of Molecular Biology and Biochemistry, Charité – Universitätsmedizin Berlin, Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Cristina Kroon
- Institute of Molecular Biology and Biochemistry, Charité – Universitätsmedizin Berlin, Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Alexandra Polyzou
- Department of Pharmacology, Faculty of Medicine, School of Health Sciences, University of Ioannina, Ioannina, Greece
| | - Britta J. Eickholt
- Institute of Molecular Biology and Biochemistry, Charité – Universitätsmedizin Berlin, Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
- *Correspondence: Britta J. Eickholt,
| | - George Leondaritis
- Department of Pharmacology, Faculty of Medicine, School of Health Sciences, University of Ioannina, Ioannina, Greece
- Institute of Biosciences, University Research Center Ioannina, University of Ioannina, Ioannina, Greece
- George Leondaritis,
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Wang D, Jin MF, Li L, Liu Y, Sun Y, Ni H. PRG5 Knockout Precipitates Late-Onset Hypersusceptibility to Pilocarpine-Induced Juvenile Seizures by Exacerbating Hippocampal Zinc Signaling-Mediated Mitochondrial Damage. Front Neurosci 2021; 15:715555. [PMID: 34512249 PMCID: PMC8430038 DOI: 10.3389/fnins.2021.715555] [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: 05/27/2021] [Accepted: 07/30/2021] [Indexed: 11/13/2022] Open
Abstract
Introduction Epileptogenesis is understood as the plastic process that produces a persistent reorganization of the brain’s neural network after a precipitating injury (recurrent neonatal seizures, for instance) with a latent period, finally leading to neuronal hyperexcitability. Plasticity-related genes (PRGs), also known as lipid phosphate phosphatase-related proteins (PLPPRs), are regulators of mitochondrial membrane integrity and energy metabolism. This study was undertaken to determine whether PRG5 gene knockout contributes to the delayed hypersensitivity induced by developmental seizures and the aberrant sprouting of hippocampal mossy fibers, and to determine whether it is achieved through the mitochondrial pathway. Here, we developed a “twist” seizure model by coupling pilocarpine-induced juvenile seizures with later exposure to penicillin to test the long-term effects of PRG5 knockout on seizure latency through comparison with wild-type (WT) mice. Hippocampal mossy fiber sprouting (MFS) was detected by Timm staining. In order to clarify the mechanism of the adverse reactions triggered by PRG5 knockout, hippocampal HT22 neuronal cultures were exposed to glutamate, with or without PRG5 interference. Mitochondrial function, oxidative stress indicators and zinc ion content were detected. Results PRG5 gene knockout significantly reduced the seizure latency, and aggravated the lowered seizure threshold induced by developmental seizures. Besides, knockout of the PRG5 gene reduced the MFS scores to a certain extent. Furthermore, PRG5 gene silencing significantly increases the zinc ion content in hippocampal neurons, impairs neuronal activity and mitochondrial function, and exacerbates glutamate-induced oxidative stress damage. Conclusion In summary, PRG5 KO is associated with significantly greater hypersusceptibility to juvenile seizures in PRG5(–/–) mice compared with WT mice. These effects may be related to the hippocampal zinc signaling. The effects do not appear to be related to changes in MFS because KO mice with juvenile seizures had the shortest seizure latencies but exhibited less MFS than WT mice with juvenile seizures.
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Affiliation(s)
- Dandan Wang
- Division of Brain Science, Institute of Pediatric Research, Children's Hospital of Soochow University, Suzhou, China.,Department of Pediatrics, First Affiliated Hospital of University of Science and Technology of China, Hefei, China
| | - Mei-Fang Jin
- Division of Brain Science, Institute of Pediatric Research, Children's Hospital of Soochow University, Suzhou, China
| | - Lili Li
- Division of Brain Science, Institute of Pediatric Research, Children's Hospital of Soochow University, Suzhou, China
| | - Yueying Liu
- Department of Pediatrics, North Branch, Affiliated Hospital of Jiangnan University, Wuxi, China
| | - Yuxiao Sun
- Division of Brain Science, Institute of Pediatric Research, Children's Hospital of Soochow University, Suzhou, China
| | - Hong Ni
- Division of Brain Science, Institute of Pediatric Research, Children's Hospital of Soochow University, Suzhou, China
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Menon S, Goldfarb D, Ho CT, Cloer EW, Boyer NP, Hardie C, Bock AJ, Johnson EC, Anil J, Major MB, Gupton SL. The TRIM9/TRIM67 neuronal interactome reveals novel activators of morphogenesis. Mol Biol Cell 2021; 32:314-330. [PMID: 33378226 PMCID: PMC8098814 DOI: 10.1091/mbc.e20-10-0622] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2020] [Revised: 11/25/2020] [Accepted: 12/17/2020] [Indexed: 12/18/2022] Open
Abstract
TRIM9 and TRIM67 are neuronally enriched E3 ubiquitin ligases essential for appropriate morphogenesis of cortical and hippocampal neurons and fidelitous responses to the axon guidance cue netrin-1. Deletion of murine Trim9 or Trim67 results in neuroanatomical defects and striking behavioral deficits, particularly in spatial learning and memory. TRIM9 and TRIM67 interact with cytoskeletal and exocytic proteins, but the full interactome is not known. Here we performed the unbiased proximity-dependent biotin identification (BioID) approach to define TRIM9 and TRIM67 protein-protein proximity network in developing cortical neurons and identified putative neuronal TRIM interaction partners. Candidates included cytoskeletal regulators, cytosolic protein transporters, exocytosis and endocytosis regulators, and proteins necessary for synaptic regulation. A subset of high-priority candidates was validated, including Myo16, Coro1A, MAP1B, ExoC1, GRIP1, PRG-1, and KIF1A. For a subset of validated candidates, we utilized total internal reflection fluorescence microscopy to demonstrate dynamic colocalization with TRIM proteins at the axonal periphery, including at the tips of filopodia. Further analysis demonstrated that the RNA interference-based knockdown of the unconventional myosin Myo16 in cortical neurons altered growth cone filopodia density and axonal branching patterns in a TRIM9- and netrin-1-dependent manner. Future analysis of other validated candidates will likely identify novel proteins and mechanisms by which TRIM9 and TRIM67 regulate neuronal form and function. [Media: see text].
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Affiliation(s)
- Shalini Menon
- Department of Cell Biology and Physiology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
| | - Dennis Goldfarb
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
| | - Chris T. Ho
- Department of Cell Biology and Physiology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
| | - Erica W. Cloer
- Department of Cell Biology and Physiology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
| | - Nicholas P. Boyer
- Neuroscience Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
| | - Christopher Hardie
- Department of Cell Biology and Physiology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
| | - Andrew J. Bock
- Department of Cell Biology and Physiology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
| | - Emma C. Johnson
- Department of Cell Biology and Physiology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
| | - Joel Anil
- Department of Cell Biology and Physiology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
| | - M. Ben Major
- Department of Cell Biology and Physiology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
| | - Stephanie L. Gupton
- Department of Cell Biology and Physiology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
- Neuroscience Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
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Altered synaptic phospholipid signaling in PRG-1 deficient mice induces exploratory behavior and motor hyperactivity resembling psychiatric disorders. Behav Brain Res 2017; 336:1-7. [PMID: 28843862 DOI: 10.1016/j.bbr.2017.08.032] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2017] [Revised: 08/15/2017] [Accepted: 08/17/2017] [Indexed: 11/23/2022]
Abstract
Plasticity related gene 1 (PRG-1) is a neuron specific membrane protein located at the postsynaptic density of glutamatergic synapses. PRG-1 modulates signaling pathways of phosphorylated lipid substrates such as lysophosphatidic acid (LPA). Deletion of PRG-1 increases presynaptic glutamate release probability leading to neuronal over-excitation. However, due to its cortical expression, PRG-1 deficiency leading to increased glutamatergic transmission is supposed to also affect motor pathways. We therefore analyzed the effects of PRG-1 function on exploratory and motor behavior using homozygous PRG-1 knockout (PRG-1-/-) mice and PRG-1/LPA2-receptor double knockout (PRG-1-/-/LPA2-/-) mice in two open field settings of different size and assessing motor behavior in the Rota Rod test. PRG-1-/- mice displayed significantly longer path lengths and higher running speed in both open field conditions. In addition, PRG-1-/- mice spent significantly longer time in the larger open field and displayed rearing and self-grooming behavior. Furthermore PRG-1-/- mice displayed stereotypical behavior resembling phenotypes of psychiatric disorders in the smaller sized open field arena. Altogether, this behavior is similar to the stereotypical behavior observed in animal models for psychiatric disease of autistic spectrum disorders which reflects a disrupted balance between glutamatergic and GABAergic synapses. These differences indicate an altered excitation/inhibition balance in neuronal circuits in PRG-1-/- mice as recently shown in the somatosensory cortex [38]. In contrast, PRG-1-/-/LPA2-/- did not show significant changes in behavior in the open field suggesting that these specific alterations were abolished when the LPA2-receptor was lacking. Our findings indicate that PRG-1 deficiency led to over-excitability caused by an altered LPA/LPA2-R signaling inducing a behavioral phenotype typically observed in animal models for psychiatric disorders.
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