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Montag D. Retrograde Amnesia - A Question of Disturbed Calcium Levels? Front Cell Neurosci 2022; 15:746198. [PMID: 34975406 PMCID: PMC8718400 DOI: 10.3389/fncel.2021.746198] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2021] [Accepted: 12/02/2021] [Indexed: 11/13/2022] Open
Abstract
Retrograde amnesia is the inability to remember events or information. The successful acquisition and memory of information is required before retrograde amnesia may occur. Often, the trigger for retrograde amnesia is a traumatic event. Loss of memories may be caused in two ways: either by loss/erasure of the memory itself or by the inability to access the memory, which is still present. In general, memories and learning are associated with a positive connotation although the extinction of unpleasant experiences and memories of traumatic events may be highly welcome. In contrast to the many experimental models addressing learning deficits caused by anterograde amnesia, the incapability to acquire new information, retrograde amnesia could so far only be investigated sporadically in human patients and in a limited number of model systems. Apart from models and diseases in which neurodegeneration or dementia like Alzheimer’s disease result in loss of memory, retrograde amnesia can be elicited by various drugs of which alcohol is the most prominent one and exemplifies the non-specific effects and the variable duration. External or internal impacts like traumatic brain injury, stroke, or electroconvulsive treatments may similarly result in variable degrees of retrograde amnesia. In this review, I will discuss a new genetic approach to induce retrograde amnesia in a mouse model and raise the hypothesis that retrograde amnesia is caused by altered intracellular calcium homeostasis. Recently, we observed that neuronal loss of neuroplastin resulted in retrograde amnesia specifically for associative memories. Neuroplastin is tightly linked to the expression of the main Ca2+ extruding pumps, the plasma membrane calcium ATPases (PMCAs). Therefore, neuronal loss of neuroplastin may block the retrieval and storage of associative memories by interference with Ca2+ signaling cascades. The possibility to elicit retrograde amnesia in a controlled manner allows to investigate the underlying mechanisms and may provide a deeper understanding of the molecular and circuit processes of memory.
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Affiliation(s)
- Dirk Montag
- Neurogenetics Laboratory, Leibniz Institute for Neurobiology, Magdeburg, Germany
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2
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Control of membrane protein homeostasis by a chaperone-like glial cell adhesion molecule at multiple subcellular locations. Sci Rep 2021; 11:18435. [PMID: 34531445 PMCID: PMC8446001 DOI: 10.1038/s41598-021-97777-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2021] [Accepted: 08/24/2021] [Indexed: 01/17/2023] Open
Abstract
The significance of crosstalks among constituents of plasma membrane protein clusters/complexes in cellular proteostasis and protein quality control (PQC) remains incompletely understood. Examining the glial (enriched) cell adhesion molecule (CAM), we demonstrate its chaperone-like role in the biosynthetic processing of the megalencephalic leukoencephalopathy with subcortical cyst 1 (MLC1)-heteromeric regulatory membrane protein complex, as well as the function of the GlialCAM/MLC1 signalling complex. We show that in the absence of GlialCAM, newly synthesized MLC1 molecules remain unfolded and are susceptible to polyubiquitination-dependent proteasomal degradation at the endoplasmic reticulum. At the plasma membrane, GlialCAM regulates the diffusional partitioning and endocytic dynamics of cluster members, including the ClC-2 chloride channel and MLC1. Impaired folding and/or expression of GlialCAM or MLC1 in the presence of diseases causing mutations, as well as plasma membrane tethering compromise the functional expression of the cluster, leading to compromised endo-lysosomal organellar identity. In addition, the enlarged endo-lysosomal compartments display accelerated acidification, ubiquitinated cargo-sorting and impaired endosomal recycling. Jointly, these observations indicate an essential and previously unrecognized role for CAM, where GliaCAM functions as a PQC factor for the MLC1 signalling complex biogenesis and possess a permissive role in the membrane dynamic and cargo sorting functions with implications in modulations of receptor signalling.
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Ilic K, Mlinac-Jerkovic K, Sedmak G, Rosenzweig I, Kalanj-Bognar S. Neuroplastin in human cognition: review of literature and future perspectives. Transl Psychiatry 2021; 11:394. [PMID: 34282131 PMCID: PMC8289873 DOI: 10.1038/s41398-021-01509-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/07/2021] [Revised: 06/16/2021] [Accepted: 06/23/2021] [Indexed: 02/07/2023] Open
Abstract
Synaptic glycoprotein neuroplastin is involved in synaptic plasticity and complex molecular events underlying learning and memory. Studies in mice and rats suggest that neuroplastin is essential for cognition, as it is needed for long-term potentiation and associative memory formation. Recently, it was found that some of the effects of neuroplastin are related to regulation of calcium homeostasis through interactions with plasma membrane calcium ATPases. Neuroplastin is increasingly seen as a key factor in complex brain functions, but studies in humans remain scarce. Here we summarize present knowledge about neuroplastin in human tissues and argue its genetic association with cortical thickness, intelligence, schizophrenia, and autism; specific immunolocalization depicting hippocampal trisynaptic pathway; potential role in tissue compensatory response in neurodegeneration; and high, almost housekeeping, level of spatio-temporal gene expression in the human brain. We also propose that neuroplastin acts as a housekeeper of neuroplasticity, and that it may be considered as an important novel cognition-related molecule in humans. Several promising directions for future investigations are suggested, which may complete our understanding of neuroplastin actions in molecular basis of human cognition.
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Affiliation(s)
- Katarina Ilic
- Croatian Institute for Brain Research, School of Medicine, University of Zagreb, Šalata12, 10000, Zagreb, Croatia
| | - Kristina Mlinac-Jerkovic
- Croatian Institute for Brain Research, School of Medicine, University of Zagreb, Šalata12, 10000, Zagreb, Croatia
| | - Goran Sedmak
- Croatian Institute for Brain Research, School of Medicine, University of Zagreb, Šalata12, 10000, Zagreb, Croatia
| | - Ivana Rosenzweig
- Sleep and Brain Plasticity Centre, Department of Neuroimaging, Institute of Psychiatry, Psychology and Neuroscience (IoPPN), King's College London (KCL), Strand, London, WC2R 2LS, UK
- Sleep Disorders Centre, Guy's and St Thomas' Hospital, Great Maze Pond, London, SE1 9RT, UK
| | - Svjetlana Kalanj-Bognar
- Croatian Institute for Brain Research, School of Medicine, University of Zagreb, Šalata12, 10000, Zagreb, Croatia.
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Lin X, Brunk MGK, Yuanxiang P, Curran AW, Zhang E, Stöber F, Goldschmidt J, Gundelfinger ED, Vollmer M, Happel MFK, Herrera-Molina R, Montag D. Neuroplastin expression is essential for hearing and hair cell PMCA expression. Brain Struct Funct 2021; 226:1533-1551. [PMID: 33844052 PMCID: PMC8096745 DOI: 10.1007/s00429-021-02269-w] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Accepted: 03/27/2021] [Indexed: 12/25/2022]
Abstract
Hearing deficits impact on the communication with the external world and severely compromise perception of the surrounding. Deafness can be caused by particular mutations in the neuroplastin (Nptn) gene, which encodes a transmembrane recognition molecule of the immunoglobulin (Ig) superfamily and plasma membrane Calcium ATPase (PMCA) accessory subunit. This study investigates whether the complete absence of neuroplastin or the loss of neuroplastin in the adult after normal development lead to hearing impairment in mice analyzed by behavioral, electrophysiological, and in vivo imaging measurements. Auditory brainstem recordings from adult neuroplastin-deficient mice (Nptn-/-) show that these mice are deaf. With age, hair cells and spiral ganglion cells degenerate in Nptn-/- mice. Adult Nptn-/- mice fail to behaviorally respond to white noise and show reduced baseline blood flow in the auditory cortex (AC) as revealed by single-photon emission computed tomography (SPECT). In adult Nptn-/- mice, tone-evoked cortical activity was not detectable within the primary auditory field (A1) of the AC, although we observed non-persistent tone-like evoked activities in electrophysiological recordings of some young Nptn-/- mice. Conditional ablation of neuroplastin in Nptnlox/loxEmx1Cre mice reveals that behavioral responses to simple tones or white noise do not require neuroplastin expression by central glutamatergic neurons. Loss of neuroplastin from hair cells in adult NptnΔlox/loxPrCreERT mice after normal development is correlated with increased hearing thresholds and only high prepulse intensities result in effective prepulse inhibition (PPI) of the startle response. Furthermore, we show that neuroplastin is required for the expression of PMCA 2 in outer hair cells. This suggests that altered Ca2+ homeostasis underlies the observed hearing impairments and leads to hair cell degeneration. Our results underline the importance of neuroplastin for the development and the maintenance of the auditory system.
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Affiliation(s)
- Xiao Lin
- Neurogenetics Laboratory, Leibniz Institute for Neurobiology, Brenneckestr. 6, 39118, Magdeburg, Germany
- Department Neurochemistry and Molecular Biology, Leibniz Institute for Neurobiology, Brenneckestr. 6, 39118, Magdeburg, Germany
| | - Michael G K Brunk
- Department System Physiology and Learning, AG CortXplorer, Leibniz Institute for Neurobiology, Brenneckestr. 6, 39118, Magdeburg, Germany
| | - Pingan Yuanxiang
- Research Group Neuroplasticity, Leibniz Institute for Neurobiology, Brenneckestr. 6, 39118, Magdeburg, Germany
| | - Andrew W Curran
- Department System Physiology and Learning, Leibniz Institute for Neurobiology, Brenneckestr. 6, 39118, Magdeburg, Germany
| | - Enqi Zhang
- Institute of Medical Psychology, Otto-Von-Guericke University Magdeburg, University Hospital, Leipziger Str. 44, 39120, Magdeburg, Germany
| | - Franziska Stöber
- Department System Physiology and Learning, Leibniz Institute for Neurobiology, Brenneckestr. 6, 39118, Magdeburg, Germany
| | - Jürgen Goldschmidt
- Department System Physiology and Learning, Leibniz Institute for Neurobiology, Brenneckestr. 6, 39118, Magdeburg, Germany
- Center for Behavioral Brain Sciences (CBBS), 39106, Magdeburg, Germany
| | - Eckart D Gundelfinger
- Department Neurochemistry and Molecular Biology, Leibniz Institute for Neurobiology, Brenneckestr. 6, 39118, Magdeburg, Germany
- Medical Faculty, Molecular Neuroscience, Otto-Von-Guericke University Magdeburg, University Hospital, Leipziger Str. 44, 39120, Magdeburg, Germany
- Center for Behavioral Brain Sciences (CBBS), 39106, Magdeburg, Germany
| | - Maike Vollmer
- Department System Physiology and Learning, Leibniz Institute for Neurobiology, Brenneckestr. 6, 39118, Magdeburg, Germany
- Department of Otolaryngology-Head and Neck Surgery, Otto-Von-Guericke University Magdeburg, University Hospital, Leipziger Str. 44, 39120, Magdeburg, Germany
| | - Max F K Happel
- Department System Physiology and Learning, AG CortXplorer, Leibniz Institute for Neurobiology, Brenneckestr. 6, 39118, Magdeburg, Germany
- Center for Behavioral Brain Sciences (CBBS), 39106, Magdeburg, Germany
| | - Rodrigo Herrera-Molina
- Department Neurochemistry and Molecular Biology, Leibniz Institute for Neurobiology, Brenneckestr. 6, 39118, Magdeburg, Germany
- Centro Integrativo de Biología Y Química Aplicada, Universidad Bernardo O'Higgins, 8307993, Santiago, Chile
- Center for Behavioral Brain Sciences (CBBS), 39106, Magdeburg, Germany
| | - Dirk Montag
- Neurogenetics Laboratory, Leibniz Institute for Neurobiology, Brenneckestr. 6, 39118, Magdeburg, Germany.
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Fairweather SJ, Shah N, Brӧer S. Heteromeric Solute Carriers: Function, Structure, Pathology and Pharmacology. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2021; 21:13-127. [PMID: 33052588 DOI: 10.1007/5584_2020_584] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Solute carriers form one of three major superfamilies of membrane transporters in humans, and include uniporters, exchangers and symporters. Following several decades of molecular characterisation, multiple solute carriers that form obligatory heteromers with unrelated subunits are emerging as a distinctive principle of membrane transporter assembly. Here we comprehensively review experimentally established heteromeric solute carriers: SLC3-SLC7 amino acid exchangers, SLC16 monocarboxylate/H+ symporters and basigin/embigin, SLC4A1 (AE1) and glycophorin A exchanger, SLC51 heteromer Ost α-Ost β uniporter, and SLC6 heteromeric symporters. The review covers the history of the heteromer discovery, transporter physiology, structure, disease associations and pharmacology - all with a focus on the heteromeric assembly. The cellular locations, requirements for complex formation, and the functional role of dimerization are extensively detailed, including analysis of the first complete heteromer structures, the SLC7-SLC3 family transporters LAT1-4F2hc, b0,+AT-rBAT and the SLC6 family heteromer B0AT1-ACE2. We present a systematic analysis of the structural and functional aspects of heteromeric solute carriers and conclude with common principles of their functional roles and structural architecture.
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Affiliation(s)
- Stephen J Fairweather
- Research School of Biology, Australian National University, Canberra, ACT, Australia. .,Resarch School of Chemistry, Australian National University, Canberra, ACT, Australia.
| | - Nishank Shah
- Research School of Biology, Australian National University, Canberra, ACT, Australia
| | - Stefan Brӧer
- Research School of Biology, Australian National University, Canberra, ACT, Australia.
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Xu J, Sun M, Li X, Huang L, Gao Z, Gao J, Xie A. MicroRNA expression profiling after recurrent febrile seizures in rat and emerging role of miR-148a-3p/SYNJ1 axis. Sci Rep 2021; 11:1262. [PMID: 33441699 PMCID: PMC7806659 DOI: 10.1038/s41598-020-79543-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2020] [Accepted: 12/04/2020] [Indexed: 02/06/2023] Open
Abstract
Febrile seizures (FSs) are common neurological disorders in both infants and children, although the precise underlying mechanism remains to be explored, especially in the expression pattern and function of microRNAs (miRNAs). In this report, we aimed to screen new potential miRNAs and examine the role of miR-148a-3p in hippocampal neurons in FS rats via Synaptojanin-1 (SYNJ1). Thirty rats were randomly divided into the normal and FS model groups, which were investigated by miRNA array. This process identified 31 differentially expressed (20 upregulated and 11 downregulated) miRNAs and potential miRNA target genes. In addition, hippocampal neurons were assigned into five groups for different transfections. Apoptosis was detected by TUNEL and flow cytometry. SYNJ1 was identified as a target gene of miR-148-3p. In vitro experiments revealed that inhibition of miR-148a-3p decreased neuronal cell apoptosis. Moreover, overexpression of miR-148a-3p resulted in activation of PI3K/Akt signaling pathway and the apoptosis of hippocampal neurons. MiR-148a-3p inhibitor could reverse the above events. Taken together, our data demonstrated that the hippocampal miRNA expression profiles of a rat model of FS provide a large database of candidate miRNAs and neuron-related target genes. Furthermore, miR-148a-3p acted as a apoptosis enhcaner via the activation of the SYNJ1/PI3K/Akt signaling pathway, highlighting a potential therapeutic target in the treatment of infants with hyperthermia-induced brain injury.
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Affiliation(s)
- Jian Xu
- grid.268079.20000 0004 1790 6079Department of Neurology, Maternal and Child Health Hospital of Weifang Medical University, Weifang, 261011 China ,grid.268079.20000 0004 1790 6079Department of Clinical Lab, Maternal and Child Health Hospital of Weifang Medical University, Weifang, 261011 China
| | - Mingqiang Sun
- grid.268079.20000 0004 1790 6079Department of Clinical Lab, Maternal and Child Health Hospital of Weifang Medical University, Weifang, 261011 China
| | - Xiaodong Li
- grid.268079.20000 0004 1790 6079Department of Pediatric, Maternal and Child Health Hospital of Weifang Medical University, Weifang, 261011 China
| | - Lei Huang
- grid.239573.90000 0000 9025 8099Department of Cancer Blood Disease, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH 45229 USA
| | - Zhenzhong Gao
- grid.268079.20000 0004 1790 6079Department of Pediatric, Maternal and Child Health Hospital of Weifang Medical University, Weifang, 261011 China
| | - Jian Gao
- grid.268079.20000 0004 1790 6079Department of Pediatric, Maternal and Child Health Hospital of Weifang Medical University, Weifang, 261011 China
| | - Anmu Xie
- grid.268079.20000 0004 1790 6079Department of Neurology, Maternal and Child Health Hospital of Weifang Medical University, Weifang, 261011 China
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Zhou J, Ma C, Wang K, Li X, Zhang H, Chen J, Li Z, Shi Y. Rare and common variants analysis of the EMB gene in patients with schizophrenia. BMC Psychiatry 2020; 20:135. [PMID: 32213169 PMCID: PMC7093976 DOI: 10.1186/s12888-020-02513-3] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/25/2019] [Accepted: 02/24/2020] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Recent genome-wide association study showed rs10940346 locus near EMB gene was significantly associated with schizophrenia and suggested that EMB gene is one of the potentially causal genes for schizophrenia, but no causal variant has been identified. Our study aims to further verify EMB gene is a susceptibility gene for schizophrenia and to identify potentially causal variants in EMB gene that lead to schizophrenia. METHODS Targeted sequencing for the un-translated region and all exons of EMB gene was performed among 1803 patients with schizophrenia and 997 healthy controls recruited from Chinese Han population. RESULTS A total of 58 high-quality variants were identified in case and control groups. Seven of them are nonsynonymous rare variations, EMB: p.(Ala52Thr), p.(Glu66Gly), p.(Ser93Cys), p.(Ala118Val), p.(Ile131Met), p.(Gly163Arg) and p.(Arg238Tyr), but none of them reached statistical significance. Among them, p.(Ile131Met), p.(Gly163Arg) and p.(Arg238Tyr), were predicted to be deleterious variants. In addition, a common variant, rs3933097 located in 3'-UTR of EMB gene, achieved allelic and genotypic significance with schizophrenia (Pallele = 3.82 × 10- 6, Pgenotype = 3.18 × 10- 5). CONCLUSIONS Our research first presented a comprehensive mutation spectrum of exons and un-translated region in EMB gene for schizophrenia and provided additional evidence of EMB gene being a susceptibility gene for schizophrenia. However, further functional validations are necessary to reveal its role in the etiology of schizophrenia.
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Affiliation(s)
- Juan Zhou
- grid.16821.3c0000 0004 0368 8293Bio-X Institutes, Key Laboratory for the Genetics of Developmental and Neuropsychiatric Disorders (Ministry of Education), Collaborative Innovation Center for Brain Science, Shanghai Jiao Tong University, Shanghai, China
| | - Chuanchuan Ma
- grid.16821.3c0000 0004 0368 8293Bio-X Institutes, Key Laboratory for the Genetics of Developmental and Neuropsychiatric Disorders (Ministry of Education), Collaborative Innovation Center for Brain Science, Shanghai Jiao Tong University, Shanghai, China
| | - Ke Wang
- grid.16821.3c0000 0004 0368 8293Bio-X Institutes, Key Laboratory for the Genetics of Developmental and Neuropsychiatric Disorders (Ministry of Education), Collaborative Innovation Center for Brain Science, Shanghai Jiao Tong University, Shanghai, China
| | - Xiuli Li
- grid.16821.3c0000 0004 0368 8293Bio-X Institutes, Key Laboratory for the Genetics of Developmental and Neuropsychiatric Disorders (Ministry of Education), Collaborative Innovation Center for Brain Science, Shanghai Jiao Tong University, Shanghai, China
| | - Han Zhang
- grid.16821.3c0000 0004 0368 8293Bio-X Institutes, Key Laboratory for the Genetics of Developmental and Neuropsychiatric Disorders (Ministry of Education), Collaborative Innovation Center for Brain Science, Shanghai Jiao Tong University, Shanghai, China
| | - Jianhua Chen
- grid.16821.3c0000 0004 0368 8293Shanghai Clinical Research Center for Mental Health, Shanghai Key Laboratory of Psychotic Disorders, Shanghai Mental Health Center, Shanghai Jiao Tong University School of Medicine, Shanghai, 200030 People’s Republic of China
| | - Zhiqiang Li
- grid.410645.20000 0001 0455 0905The Affiliated Hospital of Qingdao University & The Biomedical Sciences Institute, Qingdao University, Qingdao, China
| | - Yongyong Shi
- Bio-X Institutes, Key Laboratory for the Genetics of Developmental and Neuropsychiatric Disorders (Ministry of Education), Collaborative Innovation Center for Brain Science, Shanghai Jiao Tong University, Shanghai, China. .,Shanghai Clinical Research Center for Mental Health, Shanghai Key Laboratory of Psychotic Disorders, Shanghai Mental Health Center, Shanghai Jiao Tong University School of Medicine, Shanghai, 200030, People's Republic of China. .,The Affiliated Hospital of Qingdao University & The Biomedical Sciences Institute, Qingdao University, Qingdao, China.
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Janssens J, Philtjens S, Kleinberger G, Van Mossevelde S, van der Zee J, Cacace R, Engelborghs S, Sieben A, Banzhaf-Strathmann J, Dillen L, Merlin C, Cuijt I, Robberecht C, Schmid B, Santens P, Ivanoiu A, Vandenbulcke M, Vandenberghe R, Cras P, De Deyn PP, Martin JJ, Maudsley S, Haass C, Cruts M, Van Broeckhoven C. Investigating the role of filamin C in Belgian patients with frontotemporal dementia linked to GRN deficiency in FTLD-TDP brains. Acta Neuropathol Commun 2015; 3:68. [PMID: 26555887 PMCID: PMC4641381 DOI: 10.1186/s40478-015-0246-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2015] [Accepted: 10/21/2015] [Indexed: 12/13/2022] Open
Abstract
TAR DNA-binding protein 43 (TDP-43) inclusions are pathological hallmarks of patients with frontotemporal lobar degeneration (FTLD) and amyotrophic lateral sclerosis (ALS). Loss of TDP-43 in zebrafish engenders a severe muscle and vascular phenotype with a concomitant elevation of filamin C (FLNC) levels, an observation confirmed in the frontal cortex of FTLD-TDP patients. Here, we aimed to further assess the contribution of FLNC to frontotemporal dementia (FTD) etiology. We conducted a mutational screening of FLNC in a cohort of 529 unrelated Belgian FTD and FTD-ALS patients, and a control cohort of 920 unrelated and age-matched individuals. Additionally we performed an in-depth characterization of FLNC expression levels in FTD patients and a murine FTD model. In total 68 missense variants were identified of which 19 (MAF < 1 %) were patient-only. Gene burden analysis demonstrated a significant association between the presence of rare variants in FLNC and disease (P = 0.0349, RR = 1.46 [95 % CI 1.03–2.07]). Furthermore, elevated FLNC expression levels, observed previously in FTLD-TDP patients, were mainly attributable to FTD patients with the progranulin (GRN) p.0(IVS1 + 5G > C) loss-of-function mutation. Increased FLNC levels were, to a lesser extent, also identified in a FLNC p.V831I variant carrier and in FTD patients with the p.R159H mutation in valosin-containing protein (VCP). The GRN-associated increase of FLNC was confirmed in the frontal cortex of aged Grn knockout mice starting at 16–18 months of age. Combined quantitative proteomic and bioinformatic analyses of the frontal cortex of FTD patients possessing elevated FLNC levels, identified multiple altered protein factors involved in accelerated aging, neurodegeneration and synaptogenesis. Our findings further support the involvement of aberrant FLNC expression levels in FTD pathogenesis. Identification of increased FLNC levels in aged Grn mice and impaired pathways related to aging and neurodegeneration, implies a potential role for FLNC in mediating or accelerating the aging process.
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Beesley PW, Herrera-Molina R, Smalla KH, Seidenbecher C. The Neuroplastin adhesion molecules: key regulators of neuronal plasticity and synaptic function. J Neurochem 2014; 131:268-83. [PMID: 25040546 DOI: 10.1111/jnc.12816] [Citation(s) in RCA: 63] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2014] [Revised: 07/02/2014] [Accepted: 07/03/2014] [Indexed: 01/21/2023]
Abstract
The Neuroplastins Np65 and Np55 are neuronal and synapse-enriched immunoglobulin superfamily molecules that play important roles in a number of key neuronal and synaptic functions including, for Np65, cell adhesion. In this review we focus on the physiological roles of the Neuroplastins in promoting neurite outgrowth, regulating the structure and function of both inhibitory and excitatory synapses in brain, and in neuronal and synaptic plasticity. We discuss the underlying molecular and cellular mechanisms by which the Neuroplastins exert their physiological effects and how these are dependent upon the structural features of Np65 and Np55, which enable them to bind to a diverse range of protein partners. In turn this enables the Neuroplastins to interact with a number of key neuronal signalling cascades. These include: binding to and activation of the fibroblast growth factor receptor; Np65 trans-homophilic binding leading to activation of p38 MAPK and internalization of glutamate (GluR1) receptor subunits; acting as accessory proteins for monocarboxylate transporters, thus affecting neuronal energy supply, and binding to GABAA α1, 2 and 5 subunits, thus regulating the composition and localization of GABAA receptors. An emerging theme is the role of the Neuroplastins in regulating the trafficking and subcellular localization of specific binding partners. We also discuss the involvement of Neuroplastins in a number of pathophysiological conditions, including ischaemia, schizophrenia and breast cancer and the role of a single nucleotide polymorphism in the human Neuroplastin (NPTN) gene locus in impairment of cortical development and cognitive functions. Neuroplastins are neuronal cell adhesion molecules, which induce neurite outgrowth and play important roles in synaptic maturation and plasticity. This review summarizes the functional implications of Neuroplastins for correct synaptic membrane protein localization, neuronal energy supply, expression of LTP and LTD, animal and human behaviour, and pathophysiology and disease. It focuses particularly on Neuroplastin binding partners and signalling mechanisms, and proposes perspectives for future research on these important immunoglobulin superfamily members.
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Affiliation(s)
- Philip W Beesley
- School of Biological Sciences, Royal Holloway University of London, Egham, UK
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