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Jung T, Shin B, Tamo G, Kim H, Vijayvargia R, Leitner A, Marcaida MJ, Astorga-Wells J, Jung R, Aebersold R, Peraro MD, Hebert H, Seong IS, Song JJ. The Polyglutamine Expansion at the N-Terminal of Huntingtin Protein Modulates the Dynamic Configuration and Phosphorylation of the C-Terminal HEAT Domain. Structure 2020; 28:1035-1050.e8. [PMID: 32668197 PMCID: PMC11059206 DOI: 10.1016/j.str.2020.06.008] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2019] [Revised: 04/01/2020] [Accepted: 06/23/2020] [Indexed: 11/15/2022]
Abstract
The polyQ expansion in huntingtin protein (HTT) is the prime cause of Huntington's disease (HD). The recent cryoelectron microscopy (cryo-EM) structure of HTT-HAP40 complex provided the structural information on its HEAT-repeat domains. Here, we present analyses of the impact of polyQ length on the structure and function of HTT via an integrative structural and biochemical approach. The cryo-EM analysis of normal (Q23) and disease (Q78) type HTTs shows that the structures of apo HTTs significantly differ from the structure of HTT in a HAP40 complex and that the polyQ expansion induces global structural changes in the relative movements among the HTT domains. In addition, we show that the polyQ expansion alters the phosphorylation pattern across HTT and that Ser2116 phosphorylation in turn affects the global structure and function of HTT. These results provide a molecular basis for the effect of the polyQ segment on HTT structure and activity, which may be important for HTT pathology.
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Affiliation(s)
- Taeyang Jung
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology (KAIST), KI for the BioCentury, Daejeon 34141, Korea; School of Engineering Sciences in Chemistry, Biotechnology and Health, Department of Biomedical Engineering and Health Systems, KTH Royal Institute of Technology, 141 52 Huddinge, Sweden; Department of Biosciences and Nutrition, Karolinska Institutet, 141 83 Huddinge, Sweden
| | - Baehyun Shin
- Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA 02114, USA; Department of Neurology, Harvard Medical School, Boston, MA 02114, USA
| | - Giorgio Tamo
- Institute of Bioengineering, School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - Hyeongju Kim
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology (KAIST), KI for the BioCentury, Daejeon 34141, Korea
| | - Ravi Vijayvargia
- Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA 02114, USA; Department of Neurology, Harvard Medical School, Boston, MA 02114, USA
| | - Alexander Leitner
- Department of Biology, Institute of Molecular Systems Biology, ETH Zürich, 8093 Zürich, Switzerland
| | - Maria J Marcaida
- Institute of Bioengineering, School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - Juan Astorga-Wells
- Department of Medical Biochemistry & Biophysics, Karolinska Institutet, 171 65 Solna, Sweden; HDxperts AB, 183 48 Täby, Sweden
| | - Roy Jung
- Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA 02114, USA; Department of Neurology, Harvard Medical School, Boston, MA 02114, USA
| | - Ruedi Aebersold
- Department of Biology, Institute of Molecular Systems Biology, ETH Zürich, 8093 Zürich, Switzerland; Faculty of Science, University of Zürich, Zürich, Switzerland
| | - Matteo Dal Peraro
- Institute of Bioengineering, School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland.
| | - Hans Hebert
- School of Engineering Sciences in Chemistry, Biotechnology and Health, Department of Biomedical Engineering and Health Systems, KTH Royal Institute of Technology, 141 52 Huddinge, Sweden; Department of Biosciences and Nutrition, Karolinska Institutet, 141 83 Huddinge, Sweden.
| | - Ihn Sik Seong
- Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA 02114, USA; Department of Neurology, Harvard Medical School, Boston, MA 02114, USA.
| | - Ji-Joon Song
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology (KAIST), KI for the BioCentury, Daejeon 34141, Korea.
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2
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Schwaller B. Cytosolic Ca 2+ Buffers Are Inherently Ca 2+ Signal Modulators. Cold Spring Harb Perspect Biol 2020; 12:cshperspect.a035543. [PMID: 31308146 DOI: 10.1101/cshperspect.a035543] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
For precisely regulating intracellular Ca2+ signals in a time- and space-dependent manner, cells make use of various components of the "Ca2+ signaling toolkit," including Ca2+ entry and Ca2+ extrusion systems. A class of cytosolic Ca2+-binding proteins termed Ca2+ buffers serves as modulators of such, mostly short-lived Ca2+ signals. Prototypical Ca2+ buffers include parvalbumins (α and β isoforms), calbindin-D9k, calbindin-D28k, and calretinin. Although initially considered to function as pure Ca2+ buffers, that is, as intracellular Ca2+ signal modulators controlling the shape (amplitude, decay, spread) of Ca2+ signals, evidence has accumulated that calbindin-D28k and calretinin have additional Ca2+ sensor functions. These other functions are brought about by direct interactions with target proteins, thereby modulating their targets' function/activity. Dysregulation of Ca2+ buffer expression is associated with several neurologic/neurodevelopmental disorders including autism spectrum disorder (ASD) and schizophrenia. In some cases, the presence of these proteins is presumed to confer a neuroprotective effect, as evidenced in animal models of Parkinson's or Alzheimer's disease.
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Affiliation(s)
- Beat Schwaller
- Department of Anatomy, Section of Medicine, University of Fribourg, CH-1700 Fribourg, Switzerland
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3
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Liu Y, Feng S, Subedi K, Wang H. Attenuation of Ischemic Stroke-Caused Brain Injury by a Monoamine Oxidase Inhibitor Involves Improved Proteostasis and Reduced Neuroinflammation. Mol Neurobiol 2019; 57:937-948. [PMID: 31620993 PMCID: PMC7035161 DOI: 10.1007/s12035-019-01788-2] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2019] [Accepted: 09/12/2019] [Indexed: 01/01/2023]
Abstract
Mitochondrial dysfunction and oxidative stress play a key role in ischemia/reperfusion (I/R) induced brain injury. We previously showed that ubiquilin-1 (Ubqln1), a ubiquitin-like protein, improves proteostasis and protects brains against oxidative stress and I/R induced brain injury. We demonstrate here that nialamide (NM), a non-selective monoamine oxidase (MAO) inhibitor, upregulated Ublqn1 and protected neurons from oxygen-glucose deprivation- and I/R-caused cell death in in vitro and in vivo, respectively. Post-ischemic administration of the NM in a stroke mouse model even at 3 h following I/R still reduced neuronal injury and improved functional recovery and survival. Treating stroke animals with NM also increased the association of Ubqln1 with mitochondria and decreased the total oxidized and polyubiquitinated protein levels. Intriguingly, NM-enhanced proteostasis was also associated with reduced I/R-caused neuroinflammation, as reflected by attenuated activation of microglia and astrocytes as well as reduced TNF-α level. Thus, our results suggest that MAO inhibition-induced neuroprotection following I/R involves improved proteostasis and reduced neuroinflammation.
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Affiliation(s)
- Yanying Liu
- Division of Basic Biomedical Sciences and Center for Brain and Behavior Research, Sanford School of Medicine, University of South Dakota, Vermillion, SD, 57069, USA
| | - Shelley Feng
- Division of Basic Biomedical Sciences and Center for Brain and Behavior Research, Sanford School of Medicine, University of South Dakota, Vermillion, SD, 57069, USA
| | - Kalpana Subedi
- Division of Basic Biomedical Sciences and Center for Brain and Behavior Research, Sanford School of Medicine, University of South Dakota, Vermillion, SD, 57069, USA
| | - Hongmin Wang
- Division of Basic Biomedical Sciences and Center for Brain and Behavior Research, Sanford School of Medicine, University of South Dakota, Vermillion, SD, 57069, USA.
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Calretinin Functions in Malignant Mesothelioma Cells Cannot Be Replaced by the Closely Related Ca 2+-Binding Proteins Calbindin-D28k and Parvalbumin. Int J Mol Sci 2018; 19:ijms19124015. [PMID: 30545133 PMCID: PMC6321210 DOI: 10.3390/ijms19124015] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2018] [Revised: 12/05/2018] [Accepted: 12/10/2018] [Indexed: 01/05/2023] Open
Abstract
Calretinin (CR; CALB2) belonging to the family of EF-hand Ca2+-binding proteins (CaBP) is widely used as a positive marker for the identification of human malignant mesothelioma (MM) and functionally was suggested to play a critical role during carcinogenesis of this highly aggressive asbestos-associated neoplasm. Increasing evidence suggests that CR not only acts as a prototypical Ca2+ buffer protein, i.e., limiting the amplitude of Ca2+ signals but also as a Ca2+ sensor. No studies have yet investigated whether other closely related CaBPs might serve as substitutes for CR’s functions(s) in MM cells. Genetically modified MM cell lines with medium (MSTO-211H and ZL5) or low (SPC111) endogenous CR expression levels were generated that overexpress either CR’s closest homologue calbindin-D28k (CB) or parvalbumin (PV), the latter considered as a “pure” Ca2+ buffer protein. After lentiviral shCALB2-mediated CR downregulation, in both MSTO-211H and ZL5 cells expressing CB or PV, the CR deficiency-mediated increase in cell death was not prevented by CB or PV. With respect to proliferation and cell morphology of SPC111 cells, CB was able to substitute for CR, but not for CR’s other functions to promote cell migration or invasion. In conclusion, CR has a likely unique role in MM that cannot be substituted by “similar” CaBPs.
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5
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Calretinin promotes invasiveness and EMT in malignant mesothelioma cells involving the activation of the FAK signaling pathway. Oncotarget 2018; 9:36256-36272. [PMID: 30555628 PMCID: PMC6284738 DOI: 10.18632/oncotarget.26332] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2018] [Accepted: 10/25/2018] [Indexed: 12/29/2022] Open
Abstract
Calretinin (CR) is used as a positive marker for human malignant mesothelioma (MM) and is essential for mesothelioma cell growth/survival. Yet, the putative role(s) of CR during MM formation in vivo, binding partners or CR's influence on specific signaling pathways remain unknown. We assessed the effect of CR overexpression in the human MM cell lines MSTO-211H and SPC111. CR overexpression augmented the migration and invasion of MM cells in vitro. These effects involved the activation of the focal adhesion kinase (FAK) signaling pathway, since levels of total FAK and phospho-FAK (Tyr397) were found up-regulated in these cells. CR was also implicated in controlling epithelial-to-mesenchymal transition (EMT), evidenced by changes of the cell morphology and up-regulation of typical EMT markers. Co-IP experiments revealed FAK as a new binding partner of CR. CR co-localized with FAK at focal adhesion sites; moreover, CR-overexpressing cells displayed enhanced nuclear FAK accumulation and an increased resistance towards the FAK inhibitor VS-6063. Finally, CR downregulation via a lentiviral shRNA against CR (CALB2) resulted in a significantly reduced tumor formation in vivo in an orthotopic xenograft mouse model based on peritoneal MM cell injection. Our results indicate that CR might be considered as a possible target for MM treatment.
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Liu Y, Qiao F, Leiferman PC, Ross A, Schlenker EH, Wang H. FOXOs modulate proteasome activity in human-induced pluripotent stem cells of Huntington's disease and their derived neural cells. Hum Mol Genet 2018; 26:4416-4428. [PMID: 28973411 PMCID: PMC6075623 DOI: 10.1093/hmg/ddx327] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2017] [Accepted: 08/17/2017] [Indexed: 12/27/2022] Open
Abstract
Although it has been speculated that proteasome dysfunction may contribute to the pathogenesis of Huntington's disease (HD), a devastating neurodegenerative disorder, how proteasome activity is regulated in HD affected stem cells and somatic cells remains largely unclear. To better understand the pathogenesis of HD, we analyzed proteasome activity and the expression of FOXO transcription factors in three wild-type (WT) and three HD induced-pluripotent stem cell (iPSC) lines. HD iPSCs exhibited elevated proteasome activity and higher levels of FOXO1 and FOXO4 proteins. Knockdown of FOXO4 but not FOXO1 expression decreased proteasome activity. Following neural differentiation, the HD-iPSC-derived neural progenitor cells (NPCs) demonstrated lower levels of proteasome activity and FOXO expressions than their WT counterparts. More importantly, overexpression of FOXO4 but not FOXO1 in HD NPCs dramatically enhanced proteasome activity. When HD NPCs were further differentiated into DARPP32-positive neurons, these HD neurons were more susceptible to death than WT neurons and formed Htt aggregates under the condition of oxidative stress. Similar to HD NPCs, HD-iPSC-derived neurons showed reduced proteasome activity and diminished FOXO4 expression compared to WT-iPSC-derived neurons. Furthermore, HD iPSCs had lower AKT activities than WT iPSCs, whereas the neurons derived from HD iPSC had higher AKT activities than their WT counterparts. Inhibiting AKT activity increased both FOXO4 level and proteasome activity, indicating a potential role of AKT in regulating FOXO levels. These data suggest that FOXOs modulate proteasome activity, and thus represents a potentially valuable therapeutic target for HD.
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Affiliation(s)
- Yanying Liu
- Division of Basic Biomedical Sciences, Sanford School of Medicine, University of South Dakota, Vermillion, SD 57069, USA
| | - Fangfang Qiao
- Division of Basic Biomedical Sciences, Sanford School of Medicine, University of South Dakota, Vermillion, SD 57069, USA
| | | | - Alan Ross
- Sanford Medical Genetics Laboratory, Sioux Falls, SD 57105, USA
| | - Evelyn H Schlenker
- Division of Basic Biomedical Sciences, Sanford School of Medicine, University of South Dakota, Vermillion, SD 57069, USA
| | - Hongmin Wang
- Division of Basic Biomedical Sciences, Sanford School of Medicine, University of South Dakota, Vermillion, SD 57069, USA
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7
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Progress in developing transgenic monkey model for Huntington's disease. J Neural Transm (Vienna) 2017; 125:401-417. [PMID: 29127484 DOI: 10.1007/s00702-017-1803-y] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2016] [Accepted: 10/17/2017] [Indexed: 12/27/2022]
Abstract
Huntington's disease (HD) is a complex neurodegenerative disorder that has no cure. Although treatments can often be given to relieve symptoms, the neuropathology associated with HD cannot be stopped or reversed. HD is characterized by degeneration of the striatum and associated pathways that leads to impairment in motor and cognitive functions as well as psychiatric disturbances. Although cell and rodent models for HD exist, longitudinal study in a transgenic HD nonhuman primate (i.e., rhesus macaque; HD monkeys) shows high similarity in its progression with human patients. Progressive brain atrophy and changes in white matter integrity examined by magnetic resonance imaging are coherent with the decline in cognitive behaviors related to corticostriatal functions and neuropathology. HD monkeys also express higher anxiety and irritability/aggression similar to human HD patients that other model systems have not yet replicated. While a comparative model approach is critical for advancing our understanding of HD pathogenesis, HD monkeys could provide a unique platform for preclinical studies and long-term assessment of translatable outcome measures. This review summarizes the progress in the development of the transgenic HD monkey model and the opportunities for advancing HD preclinical research.
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8
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Paldino E, Cardinale A, D'Angelo V, Sauve I, Giampà C, Fusco FR. Selective Sparing of Striatal Interneurons after Poly (ADP-Ribose) Polymerase 1 Inhibition in the R6/2 Mouse Model of Huntington's Disease. Front Neuroanat 2017; 11:61. [PMID: 28824383 PMCID: PMC5539174 DOI: 10.3389/fnana.2017.00061] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2017] [Accepted: 07/07/2017] [Indexed: 01/02/2023] Open
Abstract
Poly (ADP-ribose) polymerases (PARPs) are enzymes that catalyze ADP-ribose units transfer from NAD to their substrate proteins. It has been observed that PARP-1 is able to increase both post-ischemic and excitotoxic neuronal death. In fact, we have previously shown that, INO-1001, a PARP-1 inhibitor, displays a neuroprotective effect in the R6/2 model of Huntington’s disease (HD). In this study, we investigated the effects of PARP-1-inhibition on modulation of phosphorylated c-AMP response element binding protein (pCREB) and CREB-binding protein (CBP) localization in the different striatal neuronal subsets. Moreover, we studied the neurodegeneration of those interneurons that are particularly vulnerable to HD such as parvalbuminergic and calretininergic, and of other subclasses of interneurons that are known to be resistant, such as cholinergic and somatostatinergic interneurons. Transgenic mice were treated with INO-1001 (10 mg/Kg daily) starting from 4 weeks of age. Double-label immunofluorescence was performed to value the distribution of CBP in ubiquitinated Neuronal intranuclear inclusions (NIIs) in the striatum. INO-1001-treated and saline-treated brain sections were incubated with: goat anti-choline acetyl transferase; goat anti-nitric oxide synthase; mouse anti-parvalbumin and mouse anti-calretinin. Morphometric evaluation and cell counts were performed. Our study showed that the PARP inhibitor has a positive effect in sparing parvalbumin and calretinin-containing interneurons of the striatum, where CREB was upregulated. Moreover, INO-1001 promoted CBP localization into the nuclei of the R6/2 mouse. The sum of our data corroborates the previous observations indicating PARP inhibition as a possible therapeutic tool to fight HD.
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Affiliation(s)
- Emanuela Paldino
- Laboratory of Neuroanatomy, Santa Lucia Foundation IRCCS HospitalRome, Italy
| | - Antonella Cardinale
- Laboratory of Neuroanatomy, Santa Lucia Foundation IRCCS HospitalRome, Italy
| | - Vincenza D'Angelo
- Department of Neuroscience, University of Rome Tor VergataRome, Italy
| | - Ilaria Sauve
- Laboratory of Neuroanatomy, Santa Lucia Foundation IRCCS HospitalRome, Italy
| | - Carmela Giampà
- Laboratory of Neuroanatomy, Santa Lucia Foundation IRCCS HospitalRome, Italy.,Department of Anatomy and Cell Biology, Catholic UniversityRome, Italy
| | - Francesca R Fusco
- Laboratory of Neuroanatomy, Santa Lucia Foundation IRCCS HospitalRome, Italy
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9
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Petryszyn S, Parent A, Parent M. The calretinin interneurons of the striatum: comparisons between rodents and primates under normal and pathological conditions. J Neural Transm (Vienna) 2017; 125:279-290. [PMID: 28168621 DOI: 10.1007/s00702-017-1687-x] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2016] [Accepted: 01/22/2017] [Indexed: 12/16/2022]
Abstract
This paper reviews the major organizational features of calretinin interneurons in the dorsal striatum of rodents and primates, with some insights on the state of these neurons in Parkinson's disease and Huntington's chorea. The rat striatum harbors medium-sized calretinin-immunoreactive (CR+) interneurons, whereas the mouse striatum is pervaded by medium-sized CR+ interneurons together with numerous small and highly immunoreactive CR+ cells. The CR interneuronal network is even more elaborated in monkey and human striatum where, in addition to the small- and medium-sized CR+ interneurons, a set of large CR+ interneurons occurs. The majority of these giant CR+ interneurons, which are unique to the primate striatum, also display immunoreactivity for choline acetyltransferase (ChAT), a faithful marker of cholinergic neurons. The expression of CR and/or ChAT by the large striatal interneurons appears to be seriously compromised in Parkinson's disease and Huntington's chorea. The species differences noted above have to be considered to better understand the role of CR interneurons in striatal organization in both normal and pathological conditions.
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Affiliation(s)
- S Petryszyn
- Department of Psychiatry and Neuroscience, Faculty of Medicine, Centre de recherche de l'Institut universitaire en santé mentale de Québec, Université Laval, 2601, Canardière, Room F-6500, Quebec, QC, G1J 2G3, Canada
| | - A Parent
- Department of Psychiatry and Neuroscience, Faculty of Medicine, Centre de recherche de l'Institut universitaire en santé mentale de Québec, Université Laval, 2601, Canardière, Room F-6500, Quebec, QC, G1J 2G3, Canada
| | - Martin Parent
- Department of Psychiatry and Neuroscience, Faculty of Medicine, Centre de recherche de l'Institut universitaire en santé mentale de Québec, Université Laval, 2601, Canardière, Room F-6500, Quebec, QC, G1J 2G3, Canada.
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Barinka F, Maglóczky Z, Zecevic N. Editorial: At the top of the interneuronal pyramid-calretinin expressing cortical interneurons. Front Neuroanat 2015; 9:108. [PMID: 26321921 PMCID: PMC4536377 DOI: 10.3389/fnana.2015.00108] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2015] [Accepted: 07/24/2015] [Indexed: 11/24/2022] Open
Affiliation(s)
- Filip Barinka
- Department of Neurology, University of Regensburg Regensburg, Germany
| | - Zsófia Maglóczky
- Institute of Experimental Medicine, Hungarian Academy of Sciences Budapest, Hungary
| | - Nada Zecevic
- Department of Neuroscience, University of Connecticut Health Center Farmington, CT, USA
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NCX1 Exchanger Cooperates with Calretinin to Confer Preconditioning-Induced Tolerance Against Cerebral Ischemia in the Striatum. Mol Neurobiol 2015; 53:1365-1376. [DOI: 10.1007/s12035-015-9095-4] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2014] [Accepted: 01/12/2015] [Indexed: 10/24/2022]
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12
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Direct reprogramming of Huntington's disease patient fibroblasts into neuron-like cells leads to abnormal neurite outgrowth, increased cell death, and aggregate formation. PLoS One 2014; 9:e109621. [PMID: 25275533 PMCID: PMC4183653 DOI: 10.1371/journal.pone.0109621] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2014] [Accepted: 09/11/2014] [Indexed: 01/01/2023] Open
Abstract
Recent advances in trans-differentiation of one type cell to another have made it possible to directly convert Huntington’s disease (HD) patient fibroblasts into neurons by modulation of cell-lineage-specific transcription factors or RNA processing. However, this possibility has not been examined. Here, we demonstrate that HD patient-derived fibroblasts can be directly trans-differentiated into neuron-like cells by knockdown of the expression of a single gene encoding the polypyrimidine-tract-binding protein. The directly converted HD neuron-like cells were positive in expression of Tuj1, NeuN, DARPP-32, and γ-aminobutyric acid and exhibited neuritic breakdown, abnormal neuritic branching, increased cell death, and aggregation of mutant huntingtin. These observations indicate that the neuron-like cells directly converted from HD patient fibroblasts recapitulate the major aspects of neuropathological characteristics of HD and thus provide an additional model for understanding the disorder and validation of therapeutic reagents.
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Brini M, Calì T, Ottolini D, Carafoli E. Neuronal calcium signaling: function and dysfunction. Cell Mol Life Sci 2014; 71:2787-814. [PMID: 24442513 PMCID: PMC11113927 DOI: 10.1007/s00018-013-1550-7] [Citation(s) in RCA: 336] [Impact Index Per Article: 33.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2013] [Revised: 12/15/2013] [Accepted: 12/30/2013] [Indexed: 01/07/2023]
Abstract
Calcium (Ca(2+)) is an universal second messenger that regulates the most important activities of all eukaryotic cells. It is of critical importance to neurons as it participates in the transmission of the depolarizing signal and contributes to synaptic activity. Neurons have thus developed extensive and intricate Ca(2+) signaling pathways to couple the Ca(2+) signal to their biochemical machinery. Ca(2+) influx into neurons occurs through plasma membrane receptors and voltage-dependent ion channels. The release of Ca(2+) from the intracellular stores, such as the endoplasmic reticulum, by intracellular channels also contributes to the elevation of cytosolic Ca(2+). Inside the cell, Ca(2+) is controlled by the buffering action of cytosolic Ca(2+)-binding proteins and by its uptake and release by mitochondria. The uptake of Ca(2+) in the mitochondrial matrix stimulates the citric acid cycle, thus enhancing ATP production and the removal of Ca(2+) from the cytosol by the ATP-driven pumps in the endoplasmic reticulum and the plasma membrane. A Na(+)/Ca(2+) exchanger in the plasma membrane also participates in the control of neuronal Ca(2+). The impaired ability of neurons to maintain an adequate energy level may impact Ca(2+) signaling: this occurs during aging and in neurodegenerative disease processes. The focus of this review is on neuronal Ca(2+) signaling and its involvement in synaptic signaling processes, neuronal energy metabolism, and neurotransmission. The contribution of altered Ca(2+) signaling in the most important neurological disorders will then be considered.
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Affiliation(s)
- Marisa Brini
- Department of Biology, University of Padova, Via U.Bassi, 58/b, 35131 Padua, Italy
| | - Tito Calì
- Department of Biology, University of Padova, Via U.Bassi, 58/b, 35131 Padua, Italy
| | - Denis Ottolini
- Department of Biology, University of Padova, Via U.Bassi, 58/b, 35131 Padua, Italy
| | - Ernesto Carafoli
- Venetian Institute for Molecular Medicine (VIMM), Via G.Orus, 2, 35129 Padua, Italy
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14
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Schwaller B. Calretinin: from a "simple" Ca(2+) buffer to a multifunctional protein implicated in many biological processes. Front Neuroanat 2014; 8:3. [PMID: 24550787 PMCID: PMC3913827 DOI: 10.3389/fnana.2014.00003] [Citation(s) in RCA: 94] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2013] [Accepted: 01/19/2014] [Indexed: 12/30/2022] Open
Abstract
The hexa-EF-hand Ca(2+)-binding protein calretinin (CR) is predominantly expressed in specific neurons of the central and peripheral nervous system. However, CR expression is also observed in non-neuronal cells, e.g., during embryonic development and in mesothelioma cells. Of the 6 EF-hand domains, 5 are functional; the first 4 domains form 2 pairs showing high cooperativity within a pair that results in non-linear modulation of intracellular Ca(2+) signals by CR. EF-hand domain 5 has a low affinity and represents the identified interaction site with CR-binding partners present in mouse cerebellar granule cells. CR binding to other targets including the pore-forming α1 subunit of the Ca(2+) channel Ca V 2.1, as well as to huntingtin indicates additional Ca(2+) sensor functions besides the well-known Ca(2+)-buffering functions. The absence of CR in cerebellar granule cells of CR(-/-) mice results in increased excitability and altered firing of Purkinje cells and promotes cerebellar 160-Hz oscillations impairing motor coordination. The putative role of CR in neuroprotection is still highly discussed. Altogether, CR emerges as a multi-functional protein also associated with development, i.e., cell proliferation, differentiation, and cell death.
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Affiliation(s)
- Beat Schwaller
- Anatomy, Department of Medicine, University of FribourgFribourg, Switzerland
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15
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Liu Y, Hettinger CL, Zhang D, Rezvani K, Wang X, Wang H. Sulforaphane enhances proteasomal and autophagic activities in mice and is a potential therapeutic reagent for Huntington's disease. J Neurochem 2014; 129:539-47. [PMID: 24383989 PMCID: PMC3997618 DOI: 10.1111/jnc.12647] [Citation(s) in RCA: 75] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2013] [Revised: 12/21/2013] [Accepted: 12/30/2013] [Indexed: 11/30/2022]
Abstract
The ubiquitin proteasome system (UPS) is impaired in Huntington's disease, a devastating neurodegenerative disorder. Sulforaphane, a naturally occurring compound, has been shown to stimulate UPS activity in cell cultures. To test whether sulforaphane enhances UPS function in vivo, we treated UPS function reporter mice ubiquitously expressing the green fluorescence protein (GFP) fused to a constitutive degradation signal that promotes its rapid degradation in the conditions of a healthy UPS. The modified GFP is termed GFP UPS reporter (GFPu). We found that both GFPu and ubiquitinated protein levels were significantly reduced and the three peptidase activities of the proteasome were increased in the brain and peripheral tissues of the mice. Interestingly, sulforaphane treatment also enhanced autophagy activity in the brain and the liver. To further examine whether sulforaphane promotes mutant huntingtin (mHtt) degradation, we treated Huntington's disease cells with sulforaphane and found that sulforaphane not only enhanced mHtt degradation but also reduced mHtt cytotoxicity. Sulforaphane-mediated mHtt degradation was mainly through the UPS pathway as the presence of a proteasome inhibitor abolished this effect. Taken together, these data indicate that sulforaphane activates protein degradation machineries in both the brain and peripheral tissues and may be a therapeutic reagent for Huntington's disease and other intractable disorders. Accumulation of mutant huntingtin (mHtt) protein causes Huntington's disease (HD). Sulforaphane (SFN), a naturally occurring compound, increased proteasome and autophagy activities in vivo and enhanced mHtt turnover and cell survival in HD cell models. SFN-mediated mHtt degradation is mainly through the proteasome pathway. These data suggest that SFN can be a therapeutic reagent for treating HD and other intractable disorders.
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Affiliation(s)
- Yanying Liu
- Division of Basic Biomedical Sciences, Sanford School of Medicine, University of South Dakota, Vermillion, South Dakota, USA
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Czeredys M, Gruszczynska-Biegala J, Schacht T, Methner A, Kuznicki J. Expression of genes encoding the calcium signalosome in cellular and transgenic models of Huntington's disease. Front Mol Neurosci 2013; 6:42. [PMID: 24324398 PMCID: PMC3838962 DOI: 10.3389/fnmol.2013.00042] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2013] [Accepted: 11/05/2013] [Indexed: 11/13/2022] Open
Abstract
Huntington's disease (HD) is a hereditary neurodegenerative disease caused by the expansion of a polyglutamine stretch in the huntingtin (HTT) protein and characterized by dysregulated calcium homeostasis. We investigated whether these disturbances are correlated with changes in the mRNA level of the genes that encode proteins involved in calcium homeostasis and signaling (i.e., the calciosome). Using custom-made TaqMan low-density arrays containing probes for 96 genes, we quantified mRNA in the striatum in YAC128 mice, a model of HD, and wildtype mice. HTT mutation caused the increased expression of some components of the calcium signalosome, including calretinin, presenilin 2, and calmyrin 1, and the increased expression of genes indirectly involved in calcium homeostasis, such as huntingtin-associated protein 1 and calcyclin-binding protein. To verify these findings in a different model, we used PC12 cells with an inducible expression of mutated full-length HTT. Using single-cell imaging with Fura-2AM, we found that store-operated Ca2+ entry but not endoplasmic reticulum (ER) store content was changed as a result of the expression of mutant HTT. Statistically significant downregulation of the Orai calcium channel subunit 2, calmodulin, and septin 4 was detected in cells that expressed mutated HTT. Our data indicate that the dysregulation of calcium homeostasis correlates with changes in the gene expression of members of the calciosome. These changes, however, differed in the two models of HD used in this study. Our results indicate that each HD model exhibits distinct features that may only partially resemble the human disease.
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Affiliation(s)
- Magdalena Czeredys
- Laboratory of Neurodegeneration, International Institute of Molecular and Cell Biology Warsaw, Poland
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Giacomello M, Oliveros JC, Naranjo JR, Carafoli E. Neuronal Ca(2+) dyshomeostasis in Huntington disease. Prion 2013; 7:76-84. [PMID: 23324594 DOI: 10.4161/pri.23581] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
The expansion of the N-terminal poly-glutamine tract of the huntingtin (Htt) protein is responsible for Huntington disease (HD). A large number of studies have explored the neuronal phenotype of HD, but the molecular aethiology of the disease is still very poorly understood. This has hampered the development of an appropriate therapeutical strategy to at least alleviate its symptoms. In this short review, we have focused our attention on the alteration of a specific cellular mechanism common to all HD models, either genetic or induced by treatment with 3-NPA, i.e. the cellular dyshomeostasis of Ca(2+). We have highlighted the direct and indirect (i.e. transcriptionally mediated) effects of mutated Htt on the maintenance of the intracellular Ca(2+) balance, the correct modulation of which is fundamental to cell survival and the disturbance of which plays a key role in the death of the cell.
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