1
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Lee SE, Lee GH. Effects of psoralidin on the expression of glutamate decarboxylases and inhibitory synapse development. JOURNAL OF ASIAN NATURAL PRODUCTS RESEARCH 2024:1-9. [PMID: 38753588 DOI: 10.1080/10286020.2024.2346297] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2023] [Accepted: 04/17/2024] [Indexed: 05/18/2024]
Abstract
Gamma-aminobutyric acid (GABA), a major inhibitory neurotransmitter required for excitation/inhibition balance is synthesized by the glutamic acid decarboxylases (GADs) in GABAergic neurons. The levels and activity of GADs are strongly correlated with GABA and neural transmission. Dysregulation of GADs and GABA is associated with various neurological disorders. The study used psoralidin, found in the seeds of Psoralea corylifolia, to investigate its effect on GAD levels and regulatory mechanisms in primary cortical neurons. Psoralidin reduced GAD67 through transcriptional regulation. The reduction was not mediated by the N-methyl-D-aspartate receptor. Additionally, psoralidin attenuated the formation of inhibitory synapses in primary hippocampal neurons.
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Affiliation(s)
- Seong-Eun Lee
- College of Pharmacy, Chosun University, Gwangju, South Korea
| | - Gum Hwa Lee
- College of Pharmacy, Chosun University, Gwangju, South Korea
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2
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Zhou Y, Xu W, Hou J, Hou C, Zhang J. Application of Free Skin Flap Transplantation in Skin Malignant Tumor Resection. JOURNAL OF ONCOLOGY 2022; 2022:7510330. [PMID: 35479963 PMCID: PMC9038399 DOI: 10.1155/2022/7510330] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/25/2021] [Revised: 01/09/2022] [Accepted: 01/20/2022] [Indexed: 11/21/2022]
Abstract
One of the most important surgical approaches for restoring cutaneous abnormalities caused by tumor resection is the insertion of a skin flap. Flap transplantation has been used to cover and fill different deficiencies after tumor removal. However, distal necrosis is among the most prevalent postsurgical consequences for skin flaps, particularly when treating large regions. Blood circulation failure causes flap necrosis, which may lead to serious problems, particularly in patients undergoing body cavity reconstruction following tumor excision. ADSCs (adipose-derived stem cells) are a kind of stem cell separated from the adipose tissue that has multilineage differentiation, simple availability, high proliferation capability, and self-renewal capabilities. This paper uses human adipose-derived stem cell (ADSC) therapy for skin flap transplantation in skin malignant tumor resection. ADSC-based therapy is an applicable technique for assisting flap transplantation. The isolation of ADSC is performed using different trypsin concentrations, and then, the population doubling time is determined. The isolated ADSCs are differentiated and then employed for the skin flap model. The performance of the suggested method is analyzed using various assays. The usage of adipose-derived stem cells to boost the vitality of the skin flaps proved successful.
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Affiliation(s)
- Yue Zhou
- Nanjing Medical University, Nanjing, Jiangsu, China
| | - Weili Xu
- Zhejiang Chinese Medical University, Hangzhou, Zhejiang, China
| | - Jue Hou
- Zhejiang Chinese Medical University, Hangzhou, Zhejiang, China
| | - Chunsheng Hou
- Affiliated Hangzhou First People's Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
| | - Jufang Zhang
- The Affiliated Hangzhou Hospital of Nanjing Medical University, Nanjing, Zhejiang, China
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3
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Costa RO, Martins H, Martins LF, Cwetsch AW, Mele M, Pedro JR, Tomé D, Jeon NL, Cancedda L, Jaffrey SR, Almeida RD. Synaptogenesis Stimulates a Proteasome-Mediated Ribosome Reduction in Axons. Cell Rep 2020; 28:864-876.e6. [PMID: 31340150 PMCID: PMC6686882 DOI: 10.1016/j.celrep.2019.06.080] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2017] [Revised: 12/21/2018] [Accepted: 06/21/2019] [Indexed: 11/19/2022] Open
Abstract
Ribosomes and a subset of cellular mRNAs are trafficked into axons of developing neurons. The axonal localization of translational machinery allows new proteins to be rapidly and locally synthesized during axonal growth and pathfinding. However, in mature neurons, axonal ribosomes are significantly reduced or even absent. The mechanism that elicits this removal is currently unknown. Here, we demonstrate that synapse formation is the trigger for ribosome reduction in mature axons. In vivo analysis shows that axonal ribosome levels decrease in rat brain at a developmental stage coincident with synapse formation. Next, we observe in vitro that different synaptogenic inducers trigger an overall decrease of ribosomal proteins and rRNA in the axons of spinal motor neurons. We further observe that this process is dependent on the ubiquitin-proteasome system but not on autophagy. Together, these data identify synaptogenesis as the long missing biological trigger that leads to ribosome disappearance during axonal maturation. The mechanism behind the striking loss of ribosomes from axons during neuronal maturation is unknown. Using in vivo and in vitro models, including neuron-muscle co-cultures and combining biochemistry and imaging techniques, Costa et al. demonstrate that synapse formation triggers ribosome reduction by a mechanism involving the ubiquitin-proteasome system.
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Affiliation(s)
- Rui O Costa
- Center for Neuroscience and Cell Biology (CNC), University of Coimbra, Coimbra, Portugal; Institute for Interdisciplinary Research, University of Coimbra, Coimbra, Portugal.
| | - Helena Martins
- Center for Neuroscience and Cell Biology (CNC), University of Coimbra, Coimbra, Portugal
| | - Luís F Martins
- Center for Neuroscience and Cell Biology (CNC), University of Coimbra, Coimbra, Portugal; Institute for Interdisciplinary Research, University of Coimbra, Coimbra, Portugal; PhD Programme in Experimental Biology and Biomedicine (PDBEB), Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal
| | - Andrzej W Cwetsch
- NBT - Department of Neuroscience and Brain Technologies, Istituto Italiano di Tecnologia, Genoa, Italy
| | - Miranda Mele
- Center for Neuroscience and Cell Biology (CNC), University of Coimbra, Coimbra, Portugal; Institute for Interdisciplinary Research, University of Coimbra, Coimbra, Portugal
| | - Joana R Pedro
- Center for Neuroscience and Cell Biology (CNC), University of Coimbra, Coimbra, Portugal
| | - Diogo Tomé
- Center for Neuroscience and Cell Biology (CNC), University of Coimbra, Coimbra, Portugal; iBiMED - Institute of Biomedicine, Department of Medical Sciences, University of Aveiro, Aveiro, Portugal
| | - Noo Li Jeon
- Institute of Advanced Machinery and Design, Seoul National University, Seoul, Republic of Korea; Department of Mechanical and Aerospace Engineering, Seoul National University, Seoul, Republic of Korea
| | - Laura Cancedda
- NBT - Department of Neuroscience and Brain Technologies, Istituto Italiano di Tecnologia, Genoa, Italy; Dulbecco Telethon Institute, Roma, Italy
| | - Samie R Jaffrey
- Department of Pharmacology, Weill Medical College of Cornell University, New York, NY 10065, USA
| | - Ramiro D Almeida
- Center for Neuroscience and Cell Biology (CNC), University of Coimbra, Coimbra, Portugal; Institute for Interdisciplinary Research, University of Coimbra, Coimbra, Portugal; iBiMED - Institute of Biomedicine, Department of Medical Sciences, University of Aveiro, Aveiro, Portugal.
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4
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The regulation of glutamic acid decarboxylases in GABA neurotransmission in the brain. Arch Pharm Res 2019; 42:1031-1039. [PMID: 31786745 DOI: 10.1007/s12272-019-01196-z] [Citation(s) in RCA: 76] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2019] [Accepted: 11/26/2019] [Indexed: 12/18/2022]
Abstract
Gamma-aminobutyric acid (GABA) is the main inhibitory neurotransmitter that is required for the control of synaptic excitation/inhibition and neural oscillation. GABA is synthesized by glutamic acid decarboxylases (GADs) that are widely distributed and localized to axon terminals of inhibitory neurons as well as to the soma and, to a lesser extent, dendrites. The expression and activity of GADs is highly correlated with GABA levels and subsequent GABAergic neurotransmission at the inhibitory synapse. Dysregulation of GADs has been implicated in various neurological disorders including epilepsy and schizophrenia. Two isoforms of GADs, GAD67 and GAD65, are expressed from separate genes and have different regulatory processes and molecular properties. This review focuses on the recent advances in understanding the structure of GAD, its transcriptional regulation and post-transcriptional modifications in the central nervous system. This may provide insights into the pathological mechanisms underlying neurological diseases that are associated with GAD dysfunction.
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5
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Hwang S, Ham S, Lee SE, Lee Y, Lee GH. Hypoxia regulates the level of glutamic acid decarboxylase enzymes and interrupts inhibitory synapse stability in primary cultured neurons. Neurotoxicology 2018; 65:221-230. [DOI: 10.1016/j.neuro.2017.10.006] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2017] [Revised: 09/19/2017] [Accepted: 10/27/2017] [Indexed: 01/23/2023]
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6
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Downregulation of glutamic acid decarboxylase in Drosophila TDP-43-null brains provokes paralysis by affecting the organization of the neuromuscular synapses. Sci Rep 2018; 8:1809. [PMID: 29379112 PMCID: PMC5789004 DOI: 10.1038/s41598-018-19802-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2017] [Accepted: 01/05/2018] [Indexed: 11/12/2022] Open
Abstract
Amyotrophic lateral sclerosis is a progressive neurodegenerative disease that affects the motor system, comprised of motoneurons and associated glia. Accordingly, neuronal or glial defects in TDP-43 function provoke paralysis due to the degeneration of the neuromuscular synapses in Drosophila. To identify the responsible molecules and mechanisms, we performed a genome wide proteomic analysis to determine differences in protein expression between wild-type and TDP-43-minus fly heads. The data established that mutant insects presented reduced levels of the enzyme glutamic acid decarboxylase (Gad1) and increased concentrations of extracellular glutamate. Genetic rescue of Gad1 activity in neurons or glia was sufficient to recuperate flies locomotion, synaptic organization and glutamate levels. Analogous recovery was obtained by treating TDP-43-null flies with glutamate receptor antagonists demonstrating that Gad1 promotes synapses formation and prevents excitotoxicity. Similar suppression of TDP-43 provoked the downregulation of GAD67, the Gad1 homolog protein in human neuroblastoma cell lines and analogous modifications were observed in iPSC-derived motoneurons from patients carrying mutations in TDP-43, uncovering conserved pathological mechanisms behind the disease.
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Abstract
Neurons cultured from rodent central nervous system tissues represent important tools in the study of neurodegenerative disease mechanisms and neuroregenerative processes, including the survival- and axon growth-promoting properties of neurotrophic factors. This chapter presents a detailed protocol for the preparation of rat and mouse cortical, hippocampal, and striatal neuron cell cultures, using either embryonic or postnatal tissue with enzymatic digestion.
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Affiliation(s)
- Laura Facci
- Department of Pharmaceutical and Pharmacological Sciences, University of Padua, Padua, Italy
| | - Stephen D Skaper
- Department of Pharmaceutical and Pharmacological Sciences, University of Padua, Padua, Italy.
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8
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Martins LF, Costa RO, Pedro JR, Aguiar P, Serra SC, Teixeira FG, Sousa N, Salgado AJ, Almeida RD. Mesenchymal stem cells secretome-induced axonal outgrowth is mediated by BDNF. Sci Rep 2017. [PMID: 28646200 PMCID: PMC5482809 DOI: 10.1038/s41598-017-03592-1] [Citation(s) in RCA: 60] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Mesenchymal stem cells (MSCs) have been used for cell-based therapies in regenerative medicine, with increasing importance in central and peripheral nervous system repair. However, MSCs grafting present disadvantages, such as, a high number of cells required for transplantation and low survival rate when transplanted into the central nervous system (CNS). In line with this, MSCs secretome which present on its composition a wide range of molecules (neurotrophins, cytokines) and microvesicles, can be a solution to surpass these problems. However, the effect of MSCs secretome in axonal elongation is poorly understood. In this study, we demonstrate that application of MSCs secretome to both rat cortical and hippocampal neurons induces an increase in axonal length. In addition, we show that this growth effect is axonal intrinsic with no contribution from the cell body. To further understand which are the molecules required for secretome-induced axonal outgrowth effect, we depleted brain-derived neurotrophic factor (BDNF) from the secretome. Our results show that in the absence of BDNF, secretome-induced axonal elongation effect is lost and that axons present a reduced axonal growth rate. Altogether, our results demonstrate that MSCs secretome is able to promote axonal outgrowth in CNS neurons and this effect is mediated by BDNF.
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Affiliation(s)
- Luís F Martins
- CNC - Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal.,PhD programme in Experimental Biology and Biomedicine (PDBEB), Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal.,Institute for Interdisciplinary Research, University of Coimbra, Coimbra, Portugal
| | - Rui O Costa
- CNC - Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal.,Institute for Interdisciplinary Research, University of Coimbra, Coimbra, Portugal
| | - Joana R Pedro
- CNC - Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal
| | - Paulo Aguiar
- INEB - Instituto de Engenharia Biomédica, i3S - Instituto de Investigação e Inovação em Saúde, Porto, Portugal
| | - Sofia C Serra
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Braga, Portugal.,ICVS/3B's-PT Government Associate Laboratory, Braga/Guimarães, Portugal
| | - Fabio G Teixeira
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Braga, Portugal.,ICVS/3B's-PT Government Associate Laboratory, Braga/Guimarães, Portugal
| | - Nuno Sousa
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Braga, Portugal.,ICVS/3B's-PT Government Associate Laboratory, Braga/Guimarães, Portugal
| | - António J Salgado
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Braga, Portugal.,ICVS/3B's-PT Government Associate Laboratory, Braga/Guimarães, Portugal
| | - Ramiro D Almeida
- CNC - Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal. .,School of Health, Polytechnic of Porto (ESS-IPP), Porto, Portugal. .,Institute for Interdisciplinary Research, University of Coimbra, Coimbra, Portugal.
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9
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Pinto MJ, Alves PL, Martins L, Pedro JR, Ryu HR, Jeon NL, Taylor AM, Almeida RD. The proteasome controls presynaptic differentiation through modulation of an on-site pool of polyubiquitinated conjugates. J Cell Biol 2016; 212:789-801. [PMID: 27022091 PMCID: PMC4810304 DOI: 10.1083/jcb.201509039] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2015] [Accepted: 02/24/2016] [Indexed: 11/22/2022] Open
Abstract
The intra-axonal events governing formation of presynaptic terminals are still poorly understood. Pinto et al. reveal a mechanism by which a localized decrease in proteasome degradation and resultant accumulation of polyubiquitinated proteins at nascent sites signal assembly of presynaptic terminals. Differentiation of the presynaptic terminal is a complex and rapid event that normally occurs in spatially specific axonal regions distant from the soma; thus, it is believed to be dependent on intra-axonal mechanisms. However, the full nature of the local events governing presynaptic assembly remains unknown. Herein, we investigated the involvement of the ubiquitin–proteasome system (UPS), the major degradative pathway, in the local modulation of presynaptic differentiation. We found that proteasome inhibition has a synaptogenic effect on isolated axons. In addition, formation of a stable cluster of synaptic vesicles onto a postsynaptic partner occurs in parallel to an on-site decrease in proteasome degradation. Accumulation of ubiquitinated proteins at nascent sites is a local trigger for presynaptic clustering. Finally, proteasome-related ubiquitin chains (K11 and K48) function as signals for the assembly of presynaptic terminals. Collectively, we propose a new axon-intrinsic mechanism for presynaptic assembly through local UPS inhibition. Subsequent on-site accumulation of proteins in their polyubiquitinated state triggers formation of presynapses.
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Affiliation(s)
- Maria J Pinto
- CNC - Center for Neuroscience and Cell Biology, University of Coimbra, 3004-517 Coimbra, Portugal PhD Program in Experimental Biology and Biomedicine, Center for Neuroscience and Cell Biology, University of Coimbra, 3004-517 Coimbra, Portugal
| | - Pedro L Alves
- Instituto de Educação e Cidadania, 3770-033 Mamarrosa, Portugal
| | - Luís Martins
- CNC - Center for Neuroscience and Cell Biology, University of Coimbra, 3004-517 Coimbra, Portugal
| | - Joana R Pedro
- CNC - Center for Neuroscience and Cell Biology, University of Coimbra, 3004-517 Coimbra, Portugal
| | - Hyun R Ryu
- Institute of Advanced Machinery and Design, Seoul National University, Seoul 151-744, Korea
| | - Noo Li Jeon
- Institute of Advanced Machinery and Design, Seoul National University, Seoul 151-744, Korea Department of Mechanical and Aerospace Engineering, Seoul National University, Seoul 151-744, Korea
| | - Anne M Taylor
- Joint Department of Biomedical Engineering, University of North Carolina at Chapel Hill and North Carolina State University, Chapel Hill, NC 27599
| | - Ramiro D Almeida
- CNC - Center for Neuroscience and Cell Biology, University of Coimbra, 3004-517 Coimbra, Portugal Institute for Interdisciplinary Research, University of Coimbra, 3004-517 Coimbra, Portugal School of Allied Health Technologies, Polytechnic Institute of Porto, 4400-330 Vila Nova de Gaia, Portugal
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10
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Pinto MJ, Pedro JR, Costa RO, Almeida RD. Visualizing K48 Ubiquitination during Presynaptic Formation By Ubiquitination-Induced Fluorescence Complementation (UiFC). Front Mol Neurosci 2016; 9:43. [PMID: 27375430 PMCID: PMC4901079 DOI: 10.3389/fnmol.2016.00043] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2016] [Accepted: 05/24/2016] [Indexed: 11/18/2022] Open
Abstract
In recent years, signaling through ubiquitin has been shown to be of great importance for normal brain development. Indeed, fluctuations in ubiquitin levels and spontaneous mutations in (de)ubiquitination enzymes greatly perturb synapse formation and neuronal transmission. In the brain, expression of lysine (K) 48-linked ubiquitin chains is higher at a developmental stage coincident with synaptogenesis. Nevertheless, no studies have so far delved into the involvement of this type of polyubiquitin chains in synapse formation. We have recently proposed a role for polyubiquitinated conjugates as triggering signals for presynaptic assembly. Herein, we aimed at characterizing the axonal distribution of K48 polyubiquitin and its dynamics throughout the course of presynaptic formation. To accomplish so, we used an ubiquitination-induced fluorescence complementation (UiFC) strategy for the visualization of K48 polyubiquitin in live hippocampal neurons. We first validated its use in neurons by analyzing changing levels of polyubiquitin. UiFC signal is diffusely distributed with distinct aggregates in somas, dendrites and axons, which perfectly colocalize with staining for a K48-specific antibody. Axonal UiFC aggregates are relatively stable and new aggregates are formed as an axon grows. Approximately 65% of UiFC aggregates colocalize with synaptic vesicle clusters and they preferentially appear in the axonal domains of axo-somatodendritic synapses when compared to isolated axons. We then evaluated axonal accumulation of K48 ubiquitinated signals in bead-induced synapses. We observed rapid accumulation of UiFC signal and endogenous K48 ubiquitin at the sites of newly formed presynapses. Lastly, we show by means of a microfluidic platform, for the isolation of axons, that presynaptic clustering on beads is dependent on E1-mediated ubiquitination at the axonal level. Altogether, these results indicate that enrichment of K48 polyubiquitin at the site of nascent presynaptic terminals is an important axon-intrinsic event for presynaptic differentiation.
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Affiliation(s)
- Maria J Pinto
- Center for Neuroscience and Cell Biology (CNC), University of CoimbraCoimbra, Portugal; PhD Programme in Experimental Biology and Biomedicine (PDBEB), Center for Neuroscience and Cell Biology, University of CoimbraCoimbra, Portugal
| | - Joana R Pedro
- Center for Neuroscience and Cell Biology (CNC), University of Coimbra Coimbra, Portugal
| | - Rui O Costa
- Center for Neuroscience and Cell Biology (CNC), University of Coimbra Coimbra, Portugal
| | - Ramiro D Almeida
- Center for Neuroscience and Cell Biology (CNC), University of CoimbraCoimbra, Portugal; School of Allied Health Technologies, Polytechnic Institute of Porto (ESTSP-IPP)Vila Nova de Gaia, Portugal; Institute for Interdisciplinary Research, University of CoimbraCoimbra, Portugal
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11
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Curcio M, Salazar IL, Mele M, Canzoniero LMT, Duarte CB. Calpains and neuronal damage in the ischemic brain: The swiss knife in synaptic injury. Prog Neurobiol 2016; 143:1-35. [PMID: 27283248 DOI: 10.1016/j.pneurobio.2016.06.001] [Citation(s) in RCA: 62] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2015] [Revised: 03/22/2016] [Accepted: 05/09/2016] [Indexed: 12/26/2022]
Abstract
The excessive extracellular accumulation of glutamate in the ischemic brain leads to an overactivation of glutamate receptors with consequent excitotoxic neuronal death. Neuronal demise is largely due to a sustained activation of NMDA receptors for glutamate, with a consequent increase in the intracellular Ca(2+) concentration and activation of calcium- dependent mechanisms. Calpains are a group of Ca(2+)-dependent proteases that truncate specific proteins, and some of the cleavage products remain in the cell, although with a distinct function. Numerous studies have shown pre- and post-synaptic effects of calpains on glutamatergic and GABAergic synapses, targeting membrane- associated proteins as well as intracellular proteins. The resulting changes in the presynaptic proteome alter neurotransmitter release, while the cleavage of postsynaptic proteins affects directly or indirectly the activity of neurotransmitter receptors and downstream mechanisms. These alterations also disturb the balance between excitatory and inhibitory neurotransmission in the brain, with an impact in neuronal demise. In this review we discuss the evidence pointing to a role for calpains in the dysregulation of excitatory and inhibitory synapses in brain ischemia, at the pre- and post-synaptic levels, as well as the functional consequences. Although targeting calpain-dependent mechanisms may constitute a good therapeutic approach for stroke, specific strategies should be developed to avoid non-specific effects given the important regulatory role played by these proteases under normal physiological conditions.
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Affiliation(s)
- Michele Curcio
- CNC - Center for Neuroscience and Cell Biology, University of Coimbra, 3004-504 Coimbra, Portugal
| | - Ivan L Salazar
- CNC - Center for Neuroscience and Cell Biology, University of Coimbra, 3004-504 Coimbra, Portugal; Doctoral Programme in Experimental Biology and Biomedicine, Center for Neuroscience and Cell Biology, University of Coimbra, 3004-504 Coimbra, Portugal; Institute for Interdisciplinary Research, University of Coimbra (IIIUC), 3030-789 Coimbra, Portugal
| | - Miranda Mele
- CNC - Center for Neuroscience and Cell Biology, University of Coimbra, 3004-504 Coimbra, Portugal
| | | | - Carlos B Duarte
- CNC - Center for Neuroscience and Cell Biology, University of Coimbra, 3004-504 Coimbra, Portugal; Department of Life Sciences, University of Coimbra, 3000-456 Coimbra, Portugal.
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12
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Hippocampal neuronal subtypes develop abnormal dendritic arbors in the presence of Fragile X astrocytes. Neuroscience 2016; 324:202-17. [DOI: 10.1016/j.neuroscience.2016.03.011] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2015] [Revised: 02/02/2016] [Accepted: 03/04/2016] [Indexed: 12/18/2022]
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13
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Mele M, Aspromonte MC, Duarte CB. Downregulation of GABA A Receptor Recycling Mediated by HAP1 Contributes to Neuronal Death in In Vitro Brain Ischemia. Mol Neurobiol 2016; 54:45-57. [PMID: 26732589 DOI: 10.1007/s12035-015-9661-9] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2015] [Accepted: 12/17/2015] [Indexed: 01/17/2023]
Abstract
Downregulation of GABAergic synaptic transmission contributes to the increase in overall excitatory activity in the ischemic brain. A reduction of GABAA receptor (GABAAR) surface expression partly accounts for this decrease in inhibitory activity, but the mechanisms involved are not fully elucidated. In this work, we investigated the alterations in GABAAR trafficking in cultured rat hippocampal neurons subjected to oxygen/glucose deprivation (OGD), an in vitro model of global brain ischemia, and their impact in neuronal death. The traffic of GABAAR was evaluated after transfection of hippocampal neurons with myc-tagged GABAAR β3 subunits. OGD decreased the rate of GABAAR β3 subunit recycling and reduced the interaction of the receptors with HAP1, a protein involved in the recycling of the receptors. Furthermore, OGD induced a calpain-mediated cleavage of HAP1. Transfection of hippocampal neurons with HAP1A or HAP1B isoforms reduced the OGD-induced decrease in surface expression of GABAAR β3 subunits, and HAP1A maintained the rate of receptor recycling. Furthermore, transfection of hippocampal neurons with HAP1 significantly decreased OGD-induced cell death. These results show a key role for HAP1 protein in the downmodulation of GABAergic neurotransmission during cerebral ischemia, which contributes to neuronal demise.
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Affiliation(s)
- Miranda Mele
- CNC-Center for Neuroscience and Cell Biology, Faculty of Medicine (Polo I), University of Coimbra, Rua Larga, 3004-504, Coimbra, Portugal.,Institute for Interdisciplinary Research (IIIUC), University of Coimbra, Coimbra, 3030-789, Portugal
| | - Maria Cristina Aspromonte
- CNC-Center for Neuroscience and Cell Biology, Faculty of Medicine (Polo I), University of Coimbra, Rua Larga, 3004-504, Coimbra, Portugal.,Department of Science and Technology, University of Sannio, Benevento, 82100, Italy
| | - Carlos B Duarte
- CNC-Center for Neuroscience and Cell Biology, Faculty of Medicine (Polo I), University of Coimbra, Rua Larga, 3004-504, Coimbra, Portugal. .,Department of Life Sciences, University of Coimbra, Coimbra, 3001-401, Portugal.
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14
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Costa JT, Mele M, Baptista MS, Gomes JR, Ruscher K, Nobre RJ, de Almeida LP, Wieloch T, Duarte CB. Gephyrin Cleavage in In Vitro Brain Ischemia Decreases GABAA Receptor Clustering and Contributes to Neuronal Death. Mol Neurobiol 2015; 53:3513-3527. [PMID: 26093381 DOI: 10.1007/s12035-015-9283-2] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2015] [Accepted: 06/02/2015] [Indexed: 02/01/2023]
Abstract
GABA (γ-aminobutyric acid) is the major inhibitory neurotransmitter in the central nervous system, and changes in GABAergic neurotransmission modulate the activity of neuronal networks. Gephyrin is a scaffold protein responsible for the traffic and synaptic anchoring of GABAA receptors (GABAAR); therefore, changes in gephyrin expression and oligomerization may affect the activity of GABAergic synapses. In this work, we investigated the changes in gephyrin protein levels during brain ischemia and in excitotoxic conditions, which may affect synaptic clustering of GABAAR. We found that gephyrin is cleaved by calpains following excitotoxic stimulation of hippocampal neurons with glutamate, as well as after intrahippocampal injection of kainate, giving rise to a stable cleavage product. Gephyrin cleavage was also observed in cultured hippocampal neurons subjected to transient oxygen-glucose deprivation (OGD), an in vitro model of brain ischemia, and after transient middle cerebral artery occlusion (MCAO) in mice, a model of focal brain ischemia. Furthermore, a truncated form of gephyrin decreased the synaptic clustering of the protein, reduced the synaptic pool of GABAAR containing γ2 subunits and upregulated OGD-induced cell death in hippocampal cultures. Our results show that excitotoxicity and brain ischemia downregulate full-length gephyrin with a concomitant generation of truncated products, which affect synaptic clustering of GABAAR and cell death.
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Affiliation(s)
- João T Costa
- CNC-Center for Neuroscience and Cell Biology, University of Coimbra, 3004-504, Coimbra, Portugal
| | - Miranda Mele
- CNC-Center for Neuroscience and Cell Biology, University of Coimbra, 3004-504, Coimbra, Portugal.,Institute for Interdisciplinary Research, University of Coimbra (IIIUC), Coimbra, 3030-789, Portugal
| | - Márcio S Baptista
- CNC-Center for Neuroscience and Cell Biology, University of Coimbra, 3004-504, Coimbra, Portugal
| | - João R Gomes
- CNC-Center for Neuroscience and Cell Biology, University of Coimbra, 3004-504, Coimbra, Portugal
| | - Karsten Ruscher
- Laboratory for Experimental Brain Research, Division of Neurosurgery, Department of Clinical Sciences, Lund University, BMC A13, S-22184, Lund, Sweden
| | - Rui J Nobre
- CNC-Center for Neuroscience and Cell Biology, University of Coimbra, 3004-504, Coimbra, Portugal.,Institute for Interdisciplinary Research, University of Coimbra (IIIUC), Coimbra, 3030-789, Portugal
| | - Luís Pereira de Almeida
- CNC-Center for Neuroscience and Cell Biology, University of Coimbra, 3004-504, Coimbra, Portugal.,Faculty of Pharmacy, University of Coimbra, Coimbra, Portugal
| | - Tadeusz Wieloch
- Laboratory for Experimental Brain Research, Division of Neurosurgery, Department of Clinical Sciences, Lund University, BMC A13, S-22184, Lund, Sweden
| | - Carlos B Duarte
- CNC-Center for Neuroscience and Cell Biology, University of Coimbra, 3004-504, Coimbra, Portugal. .,Department of Life Sciences, University of Coimbra, 3004-517, Coimbra, Portugal. .,Center for Neuroscience and Cell Biology, Faculty of Medicine, Polo I, Rua Larga, University of Coimbra, 3004-504, Coimbra, Portugal.
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15
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Mele M, Ribeiro L, Inácio AR, Wieloch T, Duarte CB. GABA(A) receptor dephosphorylation followed by internalization is coupled to neuronal death in in vitro ischemia. Neurobiol Dis 2014; 65:220-32. [PMID: 24513087 DOI: 10.1016/j.nbd.2014.01.019] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2013] [Revised: 01/08/2014] [Accepted: 01/30/2014] [Indexed: 12/22/2022] Open
Abstract
Cerebral ischemia is characterized by an early disruption of GABAergic neurotransmission contributing to an imbalance of the excitatory/inhibitory equilibrium and neuronal death, but the molecular mechanisms involved are not fully understood. Here we report a downregulation of GABA(A) receptor (GABA(A)R) expression, affecting both mRNA and protein levels of GABA(A)R subunits, in hippocampal neurons subjected to oxygen-glucose deprivation (OGD), an in vitro model of ischemia. Similar alterations in the abundance of GABA(A)R subunits were observed in in vivo brain ischemia. OGD reduced the interaction of surface GABA(A)R with the scaffold protein gephyrin, followed by clathrin-dependent receptor internalization. Internalization of GABA(A)R was dependent on glutamate receptor activation and mediated by dephosphorylation of the β3 subunit at serine 408/409. Expression of phospho-mimetic mutant GABA(A)R β3 subunits prevented receptor internalization and protected hippocampal neurons from ischemic cell death. The results show a key role for β3 GABA(A)R subunit dephosphorylation in the downregulation of GABAergic synaptic transmission in brain ischemia, contributing to neuronal death. GABA(A)R phosphorylation might be a therapeutic target to preserve synaptic inhibition in brain ischemia.
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Affiliation(s)
- Miranda Mele
- CNC-Center for Neuroscience and Cell Biology, University of Coimbra, 3004-517 Coimbra, Portugal; Department of Life Sciences, University of Coimbra, 3004-517 Coimbra, Portugal; Institute for Interdisciplinary Research, University of Coimbra (IIIUC), 3030-789 Coimbra, Portugal
| | - Luís Ribeiro
- CNC-Center for Neuroscience and Cell Biology, University of Coimbra, 3004-517 Coimbra, Portugal; Department of Life Sciences, University of Coimbra, 3004-517 Coimbra, Portugal
| | - Ana R Inácio
- Wallenberg Neuroscience Center, Lund University, 221 84 Lund, Sweden
| | - Tadeusz Wieloch
- Wallenberg Neuroscience Center, Lund University, 221 84 Lund, Sweden
| | - Carlos B Duarte
- CNC-Center for Neuroscience and Cell Biology, University of Coimbra, 3004-517 Coimbra, Portugal; Department of Life Sciences, University of Coimbra, 3004-517 Coimbra, Portugal.
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16
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Caldeira MV, Salazar IL, Curcio M, Canzoniero LMT, Duarte CB. Role of the ubiquitin-proteasome system in brain ischemia: friend or foe? Prog Neurobiol 2013; 112:50-69. [PMID: 24157661 DOI: 10.1016/j.pneurobio.2013.10.003] [Citation(s) in RCA: 94] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2013] [Revised: 10/08/2013] [Accepted: 10/15/2013] [Indexed: 11/26/2022]
Abstract
The ubiquitin-proteasome system (UPS) is a catalytic machinery that targets numerous cellular proteins for degradation, thus being essential to control a wide range of basic cellular processes and cell survival. Degradation of intracellular proteins via the UPS is a tightly regulated process initiated by tagging a target protein with a specific ubiquitin chain. Neurons are particularly vulnerable to any change in protein composition, and therefore the UPS is a key regulator of neuronal physiology. Alterations in UPS activity may induce pathological responses, ultimately leading to neuronal cell death. Brain ischemia triggers a complex series of biochemical and molecular mechanisms, such as an inflammatory response, an exacerbated production of misfolded and oxidized proteins, due to oxidative stress, and the breakdown of cellular integrity mainly mediated by excitotoxic glutamatergic signaling. Brain ischemia also damages protein degradation pathways which, together with the overproduction of damaged proteins and consequent upregulation of ubiquitin-conjugated proteins, contribute to the accumulation of ubiquitin-containing proteinaceous deposits. Despite recent advances, the factors leading to deposition of such aggregates after cerebral ischemic injury remain poorly understood. This review discusses the current knowledge on the role of the UPS in brain function and the molecular mechanisms contributing to UPS dysfunction in brain ischemia with consequent accumulation of ubiquitin-containing proteins. Chemical inhibitors of the proteasome and small molecule inhibitors of deubiquitinating enzymes, which promote the degradation of proteins by the proteasome, were both shown to provide neuroprotection in brain ischemia, and this apparent contradiction is also discussed in this review.
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Affiliation(s)
- Margarida V Caldeira
- CNC-Center for Neuroscience and Cell Biology, University of Coimbra, Largo Marquês de Pombal, 3004-517 Coimbra, Portugal; Department of Life Sciences, University of Coimbra, 3004-517 Coimbra, Portugal
| | - Ivan L Salazar
- CNC-Center for Neuroscience and Cell Biology, University of Coimbra, Largo Marquês de Pombal, 3004-517 Coimbra, Portugal; Doctoral Programme in Experimental Biology and Biomedicine, Center for Neuroscience and Cell Biology, University of Coimbra, Portugal; Institute for Interdisciplinary Research, University of Coimbra (IIIUC), Portugal
| | - Michele Curcio
- CNC-Center for Neuroscience and Cell Biology, University of Coimbra, Largo Marquês de Pombal, 3004-517 Coimbra, Portugal; Department of Science and Technology, University of Sannio, Benevento, Italy
| | | | - Carlos B Duarte
- CNC-Center for Neuroscience and Cell Biology, University of Coimbra, Largo Marquês de Pombal, 3004-517 Coimbra, Portugal; Department of Life Sciences, University of Coimbra, 3004-517 Coimbra, Portugal.
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17
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Istaphanous GK, Ward CG, Nan X, Hughes EA, McCann JC, McAuliffe JJ, Danzer SC, Loepke AW. Characterization and quantification of isoflurane-induced developmental apoptotic cell death in mouse cerebral cortex. Anesth Analg 2013; 116:845-54. [PMID: 23460572 DOI: 10.1213/ane.0b013e318281e988] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
BACKGROUND Accumulating evidence indicates that isoflurane and other, similarly acting anesthetics exert neurotoxic effects in neonatal animals. However, neither the identity of dying cortical cells nor the extent of cortical cell loss has been sufficiently characterized. We conducted the present study to immunohistochemically identify the dying cells and to quantify the fraction of cells undergoing apoptotic death in neonatal mouse cortex, a substantially affected brain region. METHODS Seven-day-old littermates (n = 36) were randomly assigned to a 6-hour exposure to either 1.5% isoflurane or fasting in room air. Animals were euthanized immediately after exposure and brain sections were double-stained for activated caspase 3 and one of the following cellular markers: Neuronal Nuclei (NeuN) for neurons, glutamic acid decarboxylase (GAD)65 and GAD67 for GABAergic cells, as well as GFAP (glial fibrillary acidic protein) and S100β for astrocytes. RESULTS In 7-day-old mice, isoflurane exposure led to widespread increases in apoptotic cell death relative to controls, as measured by activated caspase 3 immunolabeling. Confocal analyses of caspase 3-labeled cells in cortical layers II and III revealed that the overwhelming majority of cells were postmitotic neurons, but some were astrocytes. We then quantified isoflurane-induced neuronal apoptosis in visual cortex, an area of substantial injury. In unanesthetized control animals, 0.08% ± 0.001% of NeuN-positive layer II/III cortical neurons were immunoreactive for caspase 3. By contrast, the rate of apoptotic NeuN-positive neurons increased at least 11-fold (lower end of the 95% confidence interval [CI]) to 2.0% ± 0.004% of neurons immediately after isoflurane exposure (P = 0.0017 isoflurane versus control). In isoflurane-treated animals, 2.9% ± 0.02% of all caspase 3-positive neurons in superficial cortex also coexpressed GAD67, indicating that inhibitory neurons may also be affected. Analysis of GABAergic neurons, however, proved unexpectedly complex. In addition to inducing apoptosis among some GAD67-immunoreactive neurons, anesthesia also coincided with a dramatic decrease in both GAD67 (0.98 vs 1.84 ng/mg protein, P < 0.00001, anesthesia versus control) and GAD65 (2.25 ± 0.74 vs 23.03 ± 8.47 ng/mg protein, P = 0.0008, anesthesia versus control) protein levels. CONCLUSIONS Prolonged exposure to isoflurane increased neuronal apoptotic cell death in 7-day-old mice, eliminating approximately 2% of cortical neurons, of which some were identified as GABAergic interneurons. Moreover, isoflurane exposure interfered with the inhibitory nervous system by downregulating the central enzymes GAD65 and GAD67. Conversely, at this age, only a minority of degenerating cells were identified as astrocytes. The clinical relevance of these findings in animals remains to be determined.
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Affiliation(s)
- George K Istaphanous
- Department of Anesthesia, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA
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18
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Spatiotemporal resolution of BDNF neuroprotection against glutamate excitotoxicity in cultured hippocampal neurons. Neuroscience 2013; 237:66-86. [PMID: 23384605 DOI: 10.1016/j.neuroscience.2013.01.054] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2012] [Accepted: 01/28/2013] [Indexed: 02/02/2023]
Abstract
Brain-derived neurotrophic factor (BDNF) protects hippocampal neurons from glutamate excitotoxicity as determined by analysis of chromatin condensation, through activation of extracellular signal-regulated kinase (ERK) and phosphatidylinositol 3-kinase (PI3-K) signaling pathways. However, it is still unknown whether BDNF also prevents the degeneration of axons and dendrites, and the functional demise of synapses, which would be required to preserve neuronal activity. Herein, we have studied the time-dependent changes in several neurobiological markers, and the regulation of proteolytic mechanisms in cultured rat hippocampal neurons, through quantitative western blot and immunocytochemistry. Calpain activation peaked immediately after the neurodegenerative input, followed by a transient increase in ubiquitin-conjugated proteins and increased abundance of cleaved-caspase-3. Proteasome and calpain inhibition did not reproduce the protective effect of BDNF and caspase inhibition in preventing chromatin condensation. However, proteasome and calpain inhibition did protect the neuronal markers for dendrites (MAP-2), axons (Neurofilament-H) and the vesicular glutamate transporters (VGLUT1-2), whereas caspase inhibition was unable to mimic the protective effect of BDNF on neurites and synaptic markers. BDNF partially prevented the downregulation of synaptic activity measured by the KCl-evoked glutamate release using a Förster (Fluorescence) resonance energy transfer (FRET) glutamate nanosensor. These results translate a time-dependent activation of proteases and spatial segregation of these mechanisms, where calpain activation is followed by proteasome deregulation, from neuronal processes to the soma, and finally by caspase activation in the cell body. Moreover, PI3-K and PLCγ small molecule inhibitors significantly blocked the protective action of BDNF, suggesting an activity-dependent mechanism of neuroprotection. Ultimately, we hypothesize that neuronal repair after a degenerative insult is initiated at the synaptic level.
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Abstract
Neurons cultured from rodent central nervous system tissues represent an important tool in the study of neurodegenerative disease mechanisms and neuroregenerative processes, including the survival- and axon growth-promoting properties of neurotrophic factors. This chapter presents a detailed protocol for the preparation of rat and mouse cortical and hippocampal neuron cell cultures using either embryonic or postnatal tissue with enzymatic digestion.
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Affiliation(s)
- Laura Facci
- Department of Pharmacology and Anesthesiology, University of Padova, Padova, Italy
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Buddhala C, Suarez M, Modi J, Prentice H, Ma Z, Tao R, Wu JY. Calpain cleavage of brain glutamic acid decarboxylase 65 is pathological and impairs GABA neurotransmission. PLoS One 2012; 7:e33002. [PMID: 22427928 PMCID: PMC3299728 DOI: 10.1371/journal.pone.0033002] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2011] [Accepted: 02/02/2012] [Indexed: 11/19/2022] Open
Abstract
Previously, we have shown that the GABA synthesizing enzyme, L-glutamic acid decarboxylase 65 (GAD65) is cleaved to form its truncated form (tGAD65) which is 2-3 times more active than the full length form (fGAD65). The enzyme responsible for cleavage was later identified as calpain. Calpain is known to cleave its substrates either under a transient physiological stimulus or upon a sustained pathological insult. However, the precise role of calpain cleavage of fGAD65 is poorly understood. In this communication, we examined the cleavage of fGAD65 under diverse pathological conditions including rats under ischemia/reperfusion insult as well as rat brain synaptosomes and primary neuronal cultures subjected to excessive stimulation with high concentration of KCl. We have shown that the formation of tGAD65 progressively increases with increasing stimulus concentration both in rat brain synaptosomes and primary rat embryo cultures. More importantly, direct cleavage of synaptic vesicle - associated fGAD65 by calpain was demonstrated and the resulting tGAD65 bearing the active site of the enzyme was detached from the synaptic vesicles. Vesicular GABA transport of the newly synthesized GABA was found to be reduced in calpain treated SVs. Furthermore, we also observed that the levels of tGAD65 in the focal cerebral ischemic rat brain tissue increased corresponding to the elevation of local glutamate as indicated by microdialysis. Moreover, the levels of tGAD65 was also proportional to the degree of cell death when the primary neuronal cultures were exposed to high KCl. Based on these observations, we conclude that calpain-mediated cleavage of fGAD65 is pathological, presumably due to decrease in the activity of synaptic vesicle - associated fGAD65 resulting in a decrease in the GABA synthesis - packaging coupling process leading to reduced GABA neurotransmission.
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Affiliation(s)
- Chandana Buddhala
- Department of Biomedical Science, Charles E Schmidt College of Medicine, Florida Atlantic University, Boca Raton, Florida, United States of America,
| | - Marjorie Suarez
- Department of Biomedical Science, Charles E Schmidt College of Medicine, Florida Atlantic University, Boca Raton, Florida, United States of America,
| | - Jigar Modi
- Department of Biomedical Science, Charles E Schmidt College of Medicine, Florida Atlantic University, Boca Raton, Florida, United States of America,
| | - Howard Prentice
- Department of Biomedical Science, Charles E Schmidt College of Medicine, Florida Atlantic University, Boca Raton, Florida, United States of America,
| | - Zhiyuan Ma
- Department of Biomedical Science, Charles E Schmidt College of Medicine, Florida Atlantic University, Boca Raton, Florida, United States of America,
| | - Rui Tao
- Department of Biomedical Science, Charles E Schmidt College of Medicine, Florida Atlantic University, Boca Raton, Florida, United States of America,
| | - Jang Yen Wu
- Department of Biomedical Science, Charles E Schmidt College of Medicine, Florida Atlantic University, Boca Raton, Florida, United States of America,
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Rusconi L, Kilstrup-Nielsen C, Landsberger N. Extrasynaptic N-methyl-D-aspartate (NMDA) receptor stimulation induces cytoplasmic translocation of the CDKL5 kinase and its proteasomal degradation. J Biol Chem 2011; 286:36550-8. [PMID: 21832092 PMCID: PMC3196071 DOI: 10.1074/jbc.m111.235630] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Mutations in the X-linked gene cyclin-dependent kinase-like 5 (CDKL5) have been found in patients with epileptic encephalopathy characterized by early onset intractable epilepsy, including infantile spasms and other types of seizures, severe developmental delay, and often the development of Rett syndrome-like features. Despite its clear involvement in proper brain development, CDKL5 functions are still far from being understood. In this study, we analyzed the subcellular localization of the endogenous kinase in primary murine hippocampal neurons. CDKL5 was localized both in nucleus and cytoplasm and, conversely to proliferating cells, did not undergo constitutive shuttling between these compartments. Nevertheless, glutamate stimulation was able to induce the exit of the kinase from the nucleus and its subsequent accumulation in the perinuclear cytoplasm. Moreover, we found that sustained glutamate stimulation promoted CDKL5 proteasomal degradation. Both events were mediated by the specific activation of extrasynaptic pool of N-methyl-d-aspartate receptors. Proteasomal degradation was also induced by withdrawal of neurotrophic factors and hydrogen peroxide treatment, two different paradigms of cell death. Altogether, our results indicate that both subcellular localization and expression of CDKL5 are modulated by the activation of extrasynaptic N-methyl-d-aspartate receptors and suggest regulation of CDKL5 by cell death pathways.
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Affiliation(s)
- Laura Rusconi
- Laboratory of Genetic and Epigenetic Control of Gene Expression, Department of Biomedical, Informatics and Communication Sciences, University of Insubria, Busto Arsizio 21052, Italy
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Yarlagadda A, Hampe CS, Clayton AH. The blood brain barrier and the role of ratiometric molecular analysis in schizophrenia. PSYCHIATRY (EDGMONT (PA. : TOWNSHIP)) 2010; 7:20-23. [PMID: 21274392 PMCID: PMC3028465] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
The etiology of schizophrenia and other chronic psychotic disorders is complicated considering the multifactorial contribution of developmental, biological, and environmental factors. The role of the blood brain barrier has not yet been established as part of schizophrenia etiology; however, in previous blood brain barrier articles, we discussed potential consequences of various biological abnormalities due to dysregulation of molecular components, such as cofactors,(1) signaling molecules,(2) enzymes,(3) cytokines,(4) and antibodies.(5) In this review, we will discuss the potential use of peripheral ratiometric molecular analysis relevant to the central nervous system for the evaluation of the development of schizophrenia.
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Affiliation(s)
- Atmaram Yarlagadda
- Dr. Yarlagadda is Assistant Professor, Department of Psychiatry and Neurobehavioral Sciences, Charlottesville, Virginia
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