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Safari MS, Woerl P, Garmsiri C, Weber D, Kwiatkowski M, Hotze M, Kuenkel L, Lang L, Erlacher M, Gelpi E, Hainfellner JA, Baier G, Baier-Bitterlich G, Zur Nedden S. Glucose-1,6-bisphosphate: A new gatekeeper of cerebral mitochondrial pyruvate uptake. Mol Metab 2024; 88:102018. [PMID: 39182844 PMCID: PMC11404074 DOI: 10.1016/j.molmet.2024.102018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/13/2024] [Revised: 08/15/2024] [Accepted: 08/20/2024] [Indexed: 08/27/2024] Open
Abstract
OBJECTIVE Glucose-1,6-bisphosphate (G-1,6-BP), a byproduct of glycolysis that is synthesized by phosphoglucomutase 2 like 1 (PGM2L1), is particularly abundant in neurons. G-1,6-BP is sensitive to the glycolytic flux, due to its dependence on 1,3-bisphosphoglycerate as phosphate donor, and the energy state, due to its degradation by inosine monophosphate-activated phosphomannomutase 1. Since the exact role of this metabolite remains unclear, our aim was to elucidate the specific function of G-1,6-BP in the brain. METHODS The effect of PGM2L1 on neuronal post-ischemic viability was assessed by siRNA-mediated knockdown of PGM2L1 in primary mouse neurons. Acute mouse brain slices were used to correlate the reduction in G-1,6-BP upon ischemia to changes in carbon metabolism by 13C6-glucose tracing. A drug affinity responsive target stability assay was used to test if G-1,6-BP interacts with the mitochondrial pyruvate carrier (MPC) subunits in mouse brain protein extracts. Human embryonic kidney cells expressing a MPC bioluminescence resonance energy transfer sensor were used to analyze how PGM2L1 overexpression affects MPC activity. The effect of G-1,6-BP on mitochondrial pyruvate uptake and oxygen consumption rates was analyzed in isolated mouse brain mitochondria. PGM2L1 and a predicted upstream kinase were overexpressed in a human neuroblastoma cell line and G-1,6-BP levels were measured. RESULTS We found that G-1,6-BP in mouse brain slices was quickly degraded upon ischemia and reperfusion. Knockdown of PGM2L1 in mouse neurons reduced post-ischemic viability, indicating that PGM2L1 plays a neuroprotective role. The reduction in G-1,6-BP upon ischemia was not accompanied by alterations in glycolytic rates but we did see a reduced 13C6-glucose incorporation into citrate, suggesting a potential role in mitochondrial pyruvate uptake or metabolism. Indeed, G-1,6-BP interacted with both MPC subunits and overexpression of PGM2L1 increased MPC activity. G-1,6-BP, at concentrations found in the brain, enhanced mitochondrial pyruvate uptake and pyruvate-induced oxygen consumption rates. Overexpression of a predicted upstream kinase inhibited PGM2L1 activity, showing that besides metabolism, also signaling pathways can regulate G-1,6-BP levels. CONCLUSIONS We provide evidence that G-1,6-BP positively regulates mitochondrial pyruvate uptake and post-ischemic neuronal viability. These compelling data reveal a novel mechanism by which neurons can couple glycolysis-derived pyruvate to the tricarboxylic acid cycle. This process is sensitive to the glycolytic flux, the cell's energetic state, and upstream signaling cascades, offering many regulatory means to fine-tune this critical metabolic step.
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Affiliation(s)
- Motahareh Solina Safari
- CCB-Biocenter, Institute of Neurobiochemistry, Medical University of Innsbruck, 6020 Innsbruck, Austria
| | - Priska Woerl
- CCB-Biocenter, Institute of Neurobiochemistry, Medical University of Innsbruck, 6020 Innsbruck, Austria
| | - Carolin Garmsiri
- CCB-Biocenter, Institute of Neurobiochemistry, Medical University of Innsbruck, 6020 Innsbruck, Austria
| | - Dido Weber
- CCB-Biocenter, Institute of Neurobiochemistry, Medical University of Innsbruck, 6020 Innsbruck, Austria
| | - Marcel Kwiatkowski
- Department of Biochemistry, Institute of Bioanalytic & Intermediary Metabolism, University of Innsbruck, 6020 Innsbruck, Austria
| | - Madlen Hotze
- Department of Biochemistry, Institute of Bioanalytic & Intermediary Metabolism, University of Innsbruck, 6020 Innsbruck, Austria
| | - Louisa Kuenkel
- CCB-Biocenter, Institute of Neurobiochemistry, Medical University of Innsbruck, 6020 Innsbruck, Austria
| | - Luisa Lang
- CCB-Biocenter, Institute of Neurobiochemistry, Medical University of Innsbruck, 6020 Innsbruck, Austria
| | - Matthias Erlacher
- CCB-Biocenter, Institute of Genomics and RNomics, Medical University of Innsbruck, 6020 Innsbruck, Austria
| | - Ellen Gelpi
- Department of Neurology, Division of Neuropathology and Neurochemistry, Medical University of Vienna, 1090 Vienna, Austria
| | - Johannes A Hainfellner
- Department of Neurology, Division of Neuropathology and Neurochemistry, Medical University of Vienna, 1090 Vienna, Austria
| | - Gottfried Baier
- Institute for Cell Genetics, Medical University of Innsbruck, 6020 Innsbruck, Austria
| | - Gabriele Baier-Bitterlich
- CCB-Biocenter, Institute of Neurobiochemistry, Medical University of Innsbruck, 6020 Innsbruck, Austria
| | - Stephanie Zur Nedden
- CCB-Biocenter, Institute of Neurobiochemistry, Medical University of Innsbruck, 6020 Innsbruck, Austria.
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Xu Z, Xu R. Current potential diagnostic biomarkers of amyotrophic lateral sclerosis. Rev Neurosci 2024; 0:revneuro-2024-0037. [PMID: 38976599 DOI: 10.1515/revneuro-2024-0037] [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: 03/08/2024] [Accepted: 06/13/2024] [Indexed: 07/10/2024]
Abstract
Amyotrophic lateral sclerosis (ALS) currently lacks the useful diagnostic biomarkers. The current diagnosis of ALS is mainly depended on the clinical manifestations, which contributes to the diagnostic delay and be difficult to make the accurate diagnosis at the early stage of ALS, and hinders the clinical early therapeutics. The more and more pathogenesis of ALS are found at the last 30 years, including excitotoxicity, the oxidative stress, the mitochondrial dysfunction, neuroinflammation, the altered energy metabolism, the RNA misprocessing and the most recent neuroimaging findings. The findings of these pathogenesis bring the new clues for searching the diagnostic biomarkers of ALS. At present, a large number of relevant studies about the diagnostic biomarkers are underway. The ALS pathogenesis related to the diagnostic biomarkers might lessen the diagnostic reliance on the clinical manifestations. Among them, the cortical altered signatures of ALS patients derived from both structural and functional magnetic resonance imaging and the emerging proteomic biomarkers of neuronal loss and glial activation in the cerebrospinal fluid as well as the potential biomarkers in blood, serum, urine, and saliva are leading a new phase of biomarkers. Here, we reviewed these current potential diagnostic biomarkers of ALS.
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Affiliation(s)
- Zheqi Xu
- Department of Neurology, Jiangxi Provincial People's Hospital, The First Affiliated Hospital of Nanchang Medical College, Nanchang 330006, China
- The Clinical College of Nanchang Medical College, Nanchang 330006, China
- Medical College of Nanchang University, Nanchang 330006, China
| | - Renshi Xu
- Department of Neurology, Jiangxi Provincial People's Hospital, The First Affiliated Hospital of Nanchang Medical College, Nanchang 330006, China
- The Clinical College of Nanchang Medical College, Nanchang 330006, China
- Medical College of Nanchang University, Nanchang 330006, China
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Nguyen JH, Curtis MA, Imami AS, Ryan WG, Alganem K, Neifer KL, Saferin N, Nawor CN, Kistler BP, Miller GW, Shukla R, McCullumsmith RE, Burkett JP. Developmental pyrethroid exposure disrupts molecular pathways for MAP kinase and circadian rhythms in mouse brain. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.08.28.555113. [PMID: 37745438 PMCID: PMC10515776 DOI: 10.1101/2023.08.28.555113] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/26/2023]
Abstract
Neurodevelopmental disorders (NDDs) are a category of pervasive disorders of the developing nervous system with few or no recognized biomarkers. A significant portion of the risk for NDDs, including attention deficit hyperactivity disorder (ADHD), is contributed by the environment, and exposure to pyrethroid pesticides during pregnancy has been identified as a potential risk factor for NDD in the unborn child. We recently showed that low-dose developmental exposure to the pyrethroid pesticide deltamethrin in mice causes male-biased changes to ADHD- and NDD-relevant behaviors as well as the striatal dopamine system. Here, we used an integrated multiomics approach to determine the broadest possible set of biological changes in the mouse brain caused by developmental pyrethroid exposure (DPE). Using a litter-based, split-sample design, we exposed mouse dams during pregnancy and lactation to deltamethrin (3 mg/kg or vehicle every 3 days) at a concentration well below the EPA-determined benchmark dose used for regulatory guidance. We raised male offspring to adulthood, euthanized them, and pulverized and divided whole brain samples for split-sample transcriptomics, kinomics and multiomics integration. Transcriptome analysis revealed alterations to multiple canonical clock genes, and kinome analysis revealed changes in the activity of multiple kinases involved in synaptic plasticity, including the mitogen-activated protein (MAP) kinase ERK. Multiomics integration revealed a dysregulated protein-protein interaction network containing primary clusters for MAP kinase cascades, regulation of apoptosis, and synaptic function. These results demonstrate that DPE causes a multi-modal biophenotype in the brain relevant to ADHD and identifies new potential mechanisms of action. NEW & NOTEWORTHY Here, we provide the first evidence that low-dose developmental exposure to the pyrethroid pesticide, deltamethrin, results in molecular disruptions in the adult mouse brain in pathways regulating circadian rhythms and neuronal growth (MAP kinase). This same exposure causes a neurodevelopmental disorder (NDD) relevant behavioral changes in adult mice, making these findings relevant to the prevention of NDDs.
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Zhang Y, Ya D, Yang J, Jiang Y, Li X, Wang J, Tian N, Deng J, Yang B, Li Q, Liao R. EAAT3 impedes oligodendrocyte remyelination in chronic cerebral hypoperfusion-induced white matter injury. CNS Neurosci Ther 2024; 30:e14487. [PMID: 37803915 PMCID: PMC10805396 DOI: 10.1111/cns.14487] [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: 06/26/2023] [Revised: 09/20/2023] [Accepted: 09/22/2023] [Indexed: 10/08/2023] Open
Abstract
BACKGROUND Chronic cerebral hypoperfusion-induced demyelination causes progressive white matter injury, although the pathogenic pathways are unknown. METHODS The Single Cell Portal and PanglaoDB databases were used to analyze single-cell RNA sequencing experiments to determine the pattern of EAAT3 expression in CNS cells. Immunofluorescence (IF) was used to detect EAAT3 expression in oligodendrocytes and oligodendrocyte progenitor cells (OPCs). EAAT3 levels in mouse brains were measured using a western blot at various phases of development, as well as in traumatic brain injury (TBI) and intracerebral hemorrhage (ICH) mouse models. The mouse bilateral carotid artery stenosis (BCAS) model was used to create white matter injury. IF, Luxol Fast Blue staining, and electron microscopy were used to investigate the effect of remyelination. 5-Ethynyl-2-Deoxy Uridine staining, transwell chamber assays, and IF were used to examine the effects of OPCs' proliferation, migration, and differentiation in vivo and in vitro. The novel object recognition test, the Y-maze test, the rotarod test, and the grid walking test were used to examine the impact of behavioral modifications. RESULTS A considerable amount of EAAT3 was expressed in OPCs and mature oligodendrocytes, according to single-cell RNA sequencing data. During multiple critical phases of mouse brain development, there were no substantial changes in EAAT3 levels in the hippocampus, cerebral cortex, or white matter. Furthermore, neither the TBI nor ICH models significantly affected the levels of EAAT3 in the aforementioned brain areas. The chronic white matter injury caused by BCAS, on the other hand, resulted in a strikingly high level of EAAT3 expression in the oligodendroglia and white matter. Correspondingly, blocking EAAT3 assisted in the recovery of cognitive and motor impairment as well as the restoration of cerebral blood flow following BCAS. Furthermore, EAAT3 suppression was connected to improved OPCs' survival and proliferation in vivo as well as faster OPCs' proliferation, migration, and differentiation in vitro. Furthermore, this study revealed that the mTOR pathway is implicated in EAAT3-mediated remyelination. CONCLUSIONS Our findings provide the first evidence that abnormally high levels of oligodendroglial EAAT3 in chronic cerebral hypoperfusion impair OPCs' pro-remyelination actions, hence impeding white matter repair and functional recovery. EAAT3 inhibitors could be useful in the treatment of ischemia demyelination.
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Affiliation(s)
- Yingmei Zhang
- Laboratory of NeuroscienceAffiliated Hospital of Guilin Medical University, Guilin Medical UniversityGuilinChina
- Department of NeurologyAffiliated Hospital of Guilin Medical University, Guilin Medical UniversityGuilinChina
| | - Dongshan Ya
- Laboratory of NeuroscienceAffiliated Hospital of Guilin Medical University, Guilin Medical UniversityGuilinChina
- Department of NeurologyAffiliated Hospital of Guilin Medical University, Guilin Medical UniversityGuilinChina
| | - Jiaxin Yang
- Laboratory of NeuroscienceAffiliated Hospital of Guilin Medical University, Guilin Medical UniversityGuilinChina
- Department of NeurologyAffiliated Hospital of Guilin Medical University, Guilin Medical UniversityGuilinChina
| | - Yanlin Jiang
- Department of PharmacologyAffiliated Hospital of Guilin Medical University, Guilin Medical UniversityGuilinChina
| | - Xiaoxia Li
- Laboratory of NeuroscienceAffiliated Hospital of Guilin Medical University, Guilin Medical UniversityGuilinChina
- Department of NeurologyAffiliated Hospital of Guilin Medical University, Guilin Medical UniversityGuilinChina
| | - Jiawen Wang
- Laboratory of NeuroscienceAffiliated Hospital of Guilin Medical University, Guilin Medical UniversityGuilinChina
- Guangxi Clinical Research Center for Neurological DiseasesAffiliated Hospital of Guilin Medical University, Guilin Medical UniversityGuilinChina
| | - Ning Tian
- Laboratory of NeuroscienceAffiliated Hospital of Guilin Medical University, Guilin Medical UniversityGuilinChina
- Guangxi Clinical Research Center for Neurological DiseasesAffiliated Hospital of Guilin Medical University, Guilin Medical UniversityGuilinChina
| | - Jungang Deng
- Department of PharmacologyAffiliated Hospital of Guilin Medical University, Guilin Medical UniversityGuilinChina
| | - Bin Yang
- Guangxi Clinical Research Center for Neurological DiseasesAffiliated Hospital of Guilin Medical University, Guilin Medical UniversityGuilinChina
| | - Qinghua Li
- Laboratory of NeuroscienceAffiliated Hospital of Guilin Medical University, Guilin Medical UniversityGuilinChina
- Department of NeurologyAffiliated Hospital of Guilin Medical University, Guilin Medical UniversityGuilinChina
- Guangxi Clinical Research Center for Neurological DiseasesAffiliated Hospital of Guilin Medical University, Guilin Medical UniversityGuilinChina
| | - Rujia Liao
- Laboratory of NeuroscienceAffiliated Hospital of Guilin Medical University, Guilin Medical UniversityGuilinChina
- Department of NeurologyAffiliated Hospital of Guilin Medical University, Guilin Medical UniversityGuilinChina
- Guangxi Clinical Research Center for Neurological DiseasesAffiliated Hospital of Guilin Medical University, Guilin Medical UniversityGuilinChina
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Hao Y, Li Z, Zhang A, Sun L, Wang G, Wang H, Jia Z. The role of PKN1 in glioma pathogenesis and the antiglioma effect of raloxifene targeting PKN1. J Cell Mol Med 2023; 27:2730-2743. [PMID: 37480215 PMCID: PMC10494285 DOI: 10.1111/jcmm.17860] [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: 03/04/2023] [Revised: 06/29/2023] [Accepted: 07/11/2023] [Indexed: 07/23/2023] Open
Abstract
PKN1 (protein kinase N1), a serine/threonine protein kinase family member, is associated with various cancers. However, the role of PKN1 in gliomas has rarely been studied. We suggest that PKN1 expression in glioma specimens is considerably upregulated and positively correlates with the histopathological grading of gliomas. Knocking down PKN1 expression in glioblastoma (GBM) cells inhibits GBM cell proliferation, invasion and migration and promotes apoptosis. In addition, yes-associated protein (YAP) expression, an essential effector of the Hippo pathway contributing to the oncogenic role of gliomagenesis, was also downregulated. In contrast, PKN1 upregulation enhances the malignant characteristics of GBM cells and simultaneously upregulates YAP expression. Therefore, PKN1 is a promising therapeutic target for gliomas. Raloxifene (Ralo), a commonly used selective oestrogen-receptor modulator to treat osteoporosis in postmenopausal women, was predicted to target PKN1 according to the bioinformatics team from the School of Mathematics, Tianjin Nankai University. We showed that Ralo effectively targets PKN1, inhibits GBM cells proliferation and migration and sensitizes GBM cells to the major chemotherapeutic drug, Temozolomide. Ralo also reverses the effect of PKN1 on YAP activation. Thus, we confirm that PKN1 contributes to the pathogenesis of gliomas and may be a potential target for Ralo adjuvant glioma therapy.
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Affiliation(s)
- Yubing Hao
- Department of NeurosurgeryTianjin Medical University General Hospital. Tianjin Neurological Institute, Laboratory of Neuro‐Oncology, Key Laboratory of Post‐Trauma Neuro‐Repair and Regeneration in Central Nervous System, Ministry of Education. Tianjin Key Laboratory of Injuries, Variations and Regeneration of Nervous SystemTianjinP. R. China
| | - Zelin Li
- Clinical College of NeurologyNeurosurgery and Neurorehabilitation Tianjin Medical UniversityTianjinP. R. China
| | - Anling Zhang
- Department of NeurosurgeryTianjin Medical University General Hospital. Tianjin Neurological Institute, Laboratory of Neuro‐Oncology, Key Laboratory of Post‐Trauma Neuro‐Repair and Regeneration in Central Nervous System, Ministry of Education. Tianjin Key Laboratory of Injuries, Variations and Regeneration of Nervous SystemTianjinP. R. China
| | - Li Sun
- Laboratory of Neuro‐ChemistryTianjin Neurological Institute, Tianjin Medical University General HospitalTianjinChina
| | - Guangxiu Wang
- Department of NeurosurgeryTianjin Medical University General Hospital. Tianjin Neurological Institute, Laboratory of Neuro‐Oncology, Key Laboratory of Post‐Trauma Neuro‐Repair and Regeneration in Central Nervous System, Ministry of Education. Tianjin Key Laboratory of Injuries, Variations and Regeneration of Nervous SystemTianjinP. R. China
| | - Hu Wang
- Department of NeurosurgeryTianjin Huanhu HospitalTianjinChina
| | - Zhifan Jia
- Department of NeurosurgeryTianjin Medical University General Hospital. Tianjin Neurological Institute, Laboratory of Neuro‐Oncology, Key Laboratory of Post‐Trauma Neuro‐Repair and Regeneration in Central Nervous System, Ministry of Education. Tianjin Key Laboratory of Injuries, Variations and Regeneration of Nervous SystemTianjinP. R. China
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Tan SY, Jiang JX, Huang HX, Mo XP, Feng JR, Chen Y, Yang L, Long C. Neural mechanism underlies CYLD modulation of morphology and synaptic function of medium spiny neurons in dorsolateral striatum. Front Mol Neurosci 2023; 16:1107355. [PMID: 36846565 PMCID: PMC9945542 DOI: 10.3389/fnmol.2023.1107355] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2022] [Accepted: 01/17/2023] [Indexed: 02/11/2023] Open
Abstract
Although the deubiquitinase cylindromatosis (CYLD), an abundant protein in the postsynaptic density fraction, plays a crucial role in mediating the synaptic activity of the striatum, the precise molecular mechanism remains largely unclear. Here, using a Cyld-knockout mouse model, we demonstrate that CYLD regulates dorsolateral striatum (DLS) neuronal morphology, firing activity, excitatory synaptic transmission, and plasticity of striatal medium spiny neurons via, likely, interaction with glutamate receptor 1 (GluA1) and glutamate receptor 2 (GluA2), two key subunits of alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid receptors (AMPARs). CYLD deficiency reduces levels of GluA1 and GluA2 surface protein and increases K63-linked ubiquitination, resulting in functional impairments both in AMPAR-mediated excitatory postsynaptic currents and in AMPAR-dependent long-term depression. The results demonstrate a functional association of CYLD with AMPAR activity, which strengthens our understanding of the role of CYLD in striatal neuronal activity.
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Affiliation(s)
- Shu-Yi Tan
- School of Life Sciences, South China Normal University, Guangzhou, China
| | - Jin-Xiang Jiang
- School of Life Sciences, South China Normal University, Guangzhou, China
| | - Hui-Xian Huang
- School of Life Sciences, South China Normal University, Guangzhou, China
| | - Xiu-Ping Mo
- School of Life Sciences, Guangzhou University, Guangzhou, China
| | - Jing-Ru Feng
- School of Life Sciences, South China Normal University, Guangzhou, China
| | - Yu Chen
- School of Life Sciences, South China Normal University, Guangzhou, China
| | - Li Yang
- School of Life Sciences, Guangzhou University, Guangzhou, China
| | - Cheng Long
- School of Life Sciences, South China Normal University, Guangzhou, China.,South China Normal University-Panyu Central Hospital Joint Laboratory of Translational Medical Research, Panyu Central Hospital, Guangzhou, China
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New perspectives on cytoskeletal dysregulation and mitochondrial mislocalization in amyotrophic lateral sclerosis. Transl Neurodegener 2021; 10:46. [PMID: 34789332 PMCID: PMC8597313 DOI: 10.1186/s40035-021-00272-z] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2021] [Accepted: 10/28/2021] [Indexed: 02/07/2023] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disease characterized by selective, early degeneration of motor neurons in the brain and spinal cord. Motor neurons have long axonal projections, which rely on the integrity of neuronal cytoskeleton and mitochondria to regulate energy requirements for maintaining axonal stability, anterograde and retrograde transport, and signaling between neurons. The formation of protein aggregates which contain cytoskeletal proteins, and mitochondrial dysfunction both have devastating effects on the function of neurons and are shared pathological features across several neurodegenerative conditions, including ALS, Alzheimer's disease, Parkinson's disease, Huntington's disease and Charcot-Marie-Tooth disease. Furthermore, it is becoming increasingly clear that cytoskeletal integrity and mitochondrial function are intricately linked. Therefore, dysregulations of the cytoskeletal network and mitochondrial homeostasis and localization, may be common pathways in the initial steps of neurodegeneration. Here we review and discuss known contributors, including variants in genetic loci and aberrant protein activities, which modify cytoskeletal integrity, axonal transport and mitochondrial localization in ALS and have overlapping features with other neurodegenerative diseases. Additionally, we explore some emerging pathways that may contribute to this disruption in ALS.
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Safari MS, Obexer D, Baier-Bitterlich G, Zur Nedden S. PKN1 Is a Novel Regulator of Hippocampal GluA1 Levels. Front Synaptic Neurosci 2021; 13:640495. [PMID: 33613259 PMCID: PMC7892898 DOI: 10.3389/fnsyn.2021.640495] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2020] [Accepted: 01/18/2021] [Indexed: 11/13/2022] Open
Abstract
Alterations in the processes that control α-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor (AMPAR) expression, assembly and trafficking are closely linked to psychiatric and neurodegenerative disorders. We have recently shown that the serine/threonine kinase Protein kinase N1 (PKN1) is a developmentally active regulator of cerebellar synaptic maturation by inhibiting AKT and the neurogenic transcription factor neurogenic differentiation factor-2 (NeuroD2). NeuroD2 is involved in glutamatergic synaptic maturation by regulating expression levels of various synaptic proteins. Here we aimed to study the effect of Pkn1 knockout on AKT phosphorylation and NeuroD2 levels in the hippocampus and the subsequent expression levels of the NeuroD2 targets and AMPAR subunits: glutamate receptor 1 (GluA1) and GluA2/3. We show that PKN1 is expressed throughout the hippocampus. Interestingly, not only postnatal but also adult hippocampal phospho-AKT and NeuroD2 levels were significantly elevated upon Pkn1 knockout. Postnatal and adult Pkn1 -/- hippocampi showed enhanced expression of the AMPAR subunit GluA1, particularly in area CA1. Surprisingly, GluA2/3 levels were not different between both genotypes. In addition to higher protein levels, we also found an enhanced GluA1 content in the membrane fraction of postnatal and adult Pkn1 -/- animals, while GluA2/3 levels remained unchanged. This points toward a very specific regulation of GluA1 expression and/or trafficking by the novel PKN1-AKT-NeuroD2 axis. Considering the important role of GluA1 in hippocampal development as well as the pathophysiology of several disorders, ranging from Alzheimer's, to depression and schizophrenia, our results validate PKN1 for future studies into neurological disorders related to altered AMPAR subunit expression in the hippocampus.
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Affiliation(s)
- Motahareh Solina Safari
- CCB-Biocenter, Institute of Neurobiochemistry, Medical University of Innsbruck, Innsbruck, Austria
| | - Dido Obexer
- CCB-Biocenter, Institute of Neurobiochemistry, Medical University of Innsbruck, Innsbruck, Austria
| | | | - Stephanie Zur Nedden
- CCB-Biocenter, Institute of Neurobiochemistry, Medical University of Innsbruck, Innsbruck, Austria
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