1
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Ramakrishna S, Radhakrishna BK, Kaladiyil AP, Shah NM, Basavaraju N, Freude KK, Kommaddi RP, Muddashetty RS. Distinct calcium sources regulate temporal profiles of NMDAR and mGluR-mediated protein synthesis. Life Sci Alliance 2024; 7:e202402594. [PMID: 38749544 PMCID: PMC11096670 DOI: 10.26508/lsa.202402594] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2024] [Revised: 05/02/2024] [Accepted: 05/02/2024] [Indexed: 05/18/2024] Open
Abstract
Calcium signaling is integral for neuronal activity and synaptic plasticity. We demonstrate that the calcium response generated by different sources modulates neuronal activity-mediated protein synthesis, another process essential for synaptic plasticity. Stimulation of NMDARs generates a protein synthesis response involving three phases-increased translation inhibition, followed by a decrease in translation inhibition, and increased translation activation. We show that these phases are linked to NMDAR-mediated calcium response. Calcium influx through NMDARs elicits increased translation inhibition, which is necessary for the successive phases. Calcium through L-VGCCs acts as a switch from translation inhibition to the activation phase. NMDAR-mediated translation activation requires the contribution of L-VGCCs, RyRs, and SOCE. Furthermore, we show that IP3-mediated calcium release and SOCE are essential for mGluR-mediated translation up-regulation. Finally, we signify the relevance of our findings in the context of Alzheimer's disease. Using neurons derived from human fAD iPSCs and transgenic AD mice, we demonstrate the dysregulation of NMDAR-mediated calcium and translation response. Our study highlights the complex interplay between calcium signaling and protein synthesis, and its implications in neurodegeneration.
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Affiliation(s)
- Sarayu Ramakrishna
- https://ror.org/04dese585 Centre for Brain Research, Indian Institute of Science, Bangalore, India
| | - Bindushree K Radhakrishna
- https://ror.org/04dese585 Centre for Brain Research, Indian Institute of Science, Bangalore, India
- Manipal Academy of Higher Education, Manipal, India
| | - Ahamed P Kaladiyil
- https://ror.org/04dese585 Centre for Brain Research, Indian Institute of Science, Bangalore, India
| | - Nisa Manzoor Shah
- https://ror.org/04dese585 Centre for Brain Research, Indian Institute of Science, Bangalore, India
- Manipal Academy of Higher Education, Manipal, India
| | - Nimisha Basavaraju
- https://ror.org/04dese585 Centre for Brain Research, Indian Institute of Science, Bangalore, India
- Manipal Academy of Higher Education, Manipal, India
| | - Kristine K Freude
- Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Frederiksberg C, Denmark
| | - Reddy Peera Kommaddi
- https://ror.org/04dese585 Centre for Brain Research, Indian Institute of Science, Bangalore, India
| | - Ravi S Muddashetty
- https://ror.org/04dese585 Centre for Brain Research, Indian Institute of Science, Bangalore, India
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2
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Dhull A, Zhang Z, Sharma R, Dar AI, Rani A, Wei J, Gopalakrishnan S, Ghannam A, Hahn V, Pulukuri AJ, Tasevski S, Moughni S, Wu BJ, Sharma A. Discovery of 2-deoxy glucose surfaced mixed layer dendrimer: a smart neuron targeted systemic drug delivery system for brain diseases. Theranostics 2024; 14:3221-3245. [PMID: 38855177 PMCID: PMC11155412 DOI: 10.7150/thno.95476] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2024] [Accepted: 05/16/2024] [Indexed: 06/11/2024] Open
Abstract
The availability of non-invasive drug delivery systems capable of efficiently transporting bioactive molecules across the blood-brain barrier to specific cells at the injury site in the brain is currently limited. Delivering drugs to neurons presents an even more formidable challenge due to their lower numbers and less phagocytic nature compared to other brain cells. Additionally, the diverse types of neurons, each performing specific functions, necessitate precise targeting of those implicated in the disease. Moreover, the complex synthetic design of drug delivery systems often hinders their clinical translation. The production of nanomaterials at an industrial scale with high reproducibility and purity is particularly challenging. However, overcoming this challenge is possible by designing nanomaterials through a straightforward, facile, and easily reproducible synthetic process. Methods: In this study, we have developed a third-generation 2-deoxy-glucose functionalized mixed layer dendrimer (2DG-D) utilizing biocompatible and cost-effective materials via a highly facile convergent approach, employing copper-catalyzed click chemistry. We further evaluated the systemic neuronal targeting and biodistribution of 2DG-D, and brain delivery of a neuroprotective agent pioglitazone (Pio) in a pediatric traumatic brain injury (TBI) model. Results: The 2DG-D exhibits favorable characteristics including high water solubility, biocompatibility, biological stability, nanoscale size, and a substantial number of end groups suitable for drug conjugation. Upon systemic administration in a pediatric mouse model of traumatic brain injury (TBI), the 2DG-D localizes in neurons at the injured brain site, clears rapidly from off-target locations, effectively delivers Pio, ameliorates neuroinflammation, and improves behavioral outcomes. Conclusions: The promising in vivo results coupled with a convenient synthetic approach for the construction of 2DG-D makes it a potential nanoplatform for addressing brain diseases.
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Affiliation(s)
- Anubhav Dhull
- Department of Chemistry, College of Arts and Sciences, Washington State University, 1470 NE College Ave, Pullman, WA, USA 99164
| | - Zhi Zhang
- Department of Natural Sciences, College of Arts, Sciences, and Letters, University of Michigan -Dearborn, 4901 Evergreen Rd, Dearborn, MI, USA 48128
| | - Rishi Sharma
- Department of Chemistry, College of Arts and Sciences, Washington State University, 1470 NE College Ave, Pullman, WA, USA 99164
| | - Aqib Iqbal Dar
- Department of Chemistry, College of Arts and Sciences, Washington State University, 1470 NE College Ave, Pullman, WA, USA 99164
| | - Anu Rani
- Department of Chemistry, College of Arts and Sciences, Washington State University, 1470 NE College Ave, Pullman, WA, USA 99164
| | - Jing Wei
- Department of Pharmaceutical Sciences, College of Pharmacy and Pharmaceutical Sciences, Washington State University, Spokane, WA, USA 99202
| | - Shamila Gopalakrishnan
- Department of Chemistry, College of Arts and Sciences, Washington State University, 1470 NE College Ave, Pullman, WA, USA 99164
| | - Amanda Ghannam
- Department of Natural Sciences, College of Arts, Sciences, and Letters, University of Michigan -Dearborn, 4901 Evergreen Rd, Dearborn, MI, USA 48128
| | - Victoria Hahn
- Department of Natural Sciences, College of Arts, Sciences, and Letters, University of Michigan -Dearborn, 4901 Evergreen Rd, Dearborn, MI, USA 48128
| | - Anunay James Pulukuri
- Department of Chemistry, College of Arts and Sciences, Washington State University, 1470 NE College Ave, Pullman, WA, USA 99164
| | - Stefanie Tasevski
- Department of Natural Sciences, College of Arts, Sciences, and Letters, University of Michigan -Dearborn, 4901 Evergreen Rd, Dearborn, MI, USA 48128
| | - Sara Moughni
- Department of Natural Sciences, College of Arts, Sciences, and Letters, University of Michigan -Dearborn, 4901 Evergreen Rd, Dearborn, MI, USA 48128
| | - Boyang Jason Wu
- Department of Pharmaceutical Sciences, College of Pharmacy and Pharmaceutical Sciences, Washington State University, Spokane, WA, USA 99202
| | - Anjali Sharma
- Department of Chemistry, College of Arts and Sciences, Washington State University, 1470 NE College Ave, Pullman, WA, USA 99164
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3
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Oliveira MM, Mohamed M, Elder MK, Banegas-Morales K, Mamcarz M, Lu EH, Golhan EAN, Navrange N, Chatterjee S, Abel T, Klann E. The integrated stress response effector GADD34 is repurposed by neurons to promote stimulus-induced translation. Cell Rep 2024; 43:113670. [PMID: 38219147 PMCID: PMC10964249 DOI: 10.1016/j.celrep.2023.113670] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2023] [Revised: 10/11/2023] [Accepted: 12/26/2023] [Indexed: 01/16/2024] Open
Abstract
Neuronal protein synthesis is required for long-lasting plasticity and long-term memory consolidation. Dephosphorylation of eukaryotic initiation factor 2α is one of the key translational control events that is required to increase de novo protein synthesis that underlies long-lasting plasticity and memory consolidation. Here, we interrogate the molecular pathways of translational control that are triggered by neuronal stimulation with brain-derived neurotrophic factor (BDNF), which results in eukaryotic initiation factor 2α (eIF2α) dephosphorylation and increases in de novo protein synthesis. Primary rodent neurons exposed to BDNF display elevated translation of GADD34, which facilitates eIF2α dephosphorylation and subsequent de novo protein synthesis. Furthermore, GADD34 requires G-actin generated by cofilin to dephosphorylate eIF2α and enhance protein synthesis. Finally, GADD34 is required for BDNF-induced translation of synaptic plasticity-related proteins. Overall, we provide evidence that neurons repurpose GADD34, an effector of the integrated stress response, as an orchestrator of rapid increases in eIF2-dependent translation in response to plasticity-inducing stimuli.
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Affiliation(s)
| | - Muhaned Mohamed
- Center for Neural Science, New York University, New York, NY, USA
| | - Megan K Elder
- Center for Neural Science, New York University, New York, NY, USA
| | | | - Maggie Mamcarz
- Center for Neural Science, New York University, New York, NY, USA
| | - Emily H Lu
- Center for Neural Science, New York University, New York, NY, USA
| | - Ela A N Golhan
- Center for Neural Science, New York University, New York, NY, USA
| | - Nishika Navrange
- Center for Neural Science, New York University, New York, NY, USA
| | - Snehajyoti Chatterjee
- Department of Neuroscience and Pharmacology, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
| | - Ted Abel
- Department of Neuroscience and Pharmacology, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
| | - Eric Klann
- Center for Neural Science, New York University, New York, NY, USA; NYU Neuroscience Institute, New York University School of Medicine, New York, NY, USA.
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4
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Chen J, Ding Q, An L, Wang H. Ca2+-stimulated adenylyl cyclases as therapeutic targets for psychiatric and neurodevelopmental disorders. Front Pharmacol 2022; 13:949384. [PMID: 36188604 PMCID: PMC9523369 DOI: 10.3389/fphar.2022.949384] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2022] [Accepted: 09/05/2022] [Indexed: 11/13/2022] Open
Abstract
As the main secondary messengers, cyclic AMP (cAMP) and Ca2+ trigger intracellular signal transduction cascade and, in turn, regulate many aspects of cellular function in developing and mature neurons. The group I adenylyl cyclase (ADCY, also known as AC) isoforms, including ADCY1, 3, and 8 (also known as AC1, AC3, and AC8), are stimulated by Ca2+ and thus functionally positioned to integrate cAMP and Ca2+ signaling. Emerging lines of evidence have suggested the association of the Ca2+-stimulated ADCYs with bipolar disorder, schizophrenia, major depressive disorder, post-traumatic stress disorder, and autism. In this review, we discuss the molecular and cellular features as well as the physiological functions of ADCY1, 3, and 8. We further discuss the recent therapeutic development to target the Ca2+-stimulated ADCYs for potential treatments of psychiatric and neurodevelopmental disorders.
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5
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Morcuende A, García-Gutiérrez MS, Tambaro S, Nieto E, Manzanares J, Femenia T. Immunomodulatory Role of CB2 Receptors in Emotional and Cognitive Disorders. Front Psychiatry 2022; 13:866052. [PMID: 35492718 PMCID: PMC9051035 DOI: 10.3389/fpsyt.2022.866052] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/30/2022] [Accepted: 03/07/2022] [Indexed: 12/15/2022] Open
Abstract
Emotional behavior, memory, and learning have been associated with alterations in the immune system in neuropsychiatric and neurodegenerative diseases. In recent years, several studies pointed out the involvement of the cannabinoid receptor 2 (CB2r) in the immune system and the regulation of inflammation. This receptor is widely distributed in different tissues and organs with higher expression in spleen and immune system cells. However, CB2r has also been detected in several brain areas and different brain cell types, such as neurons and glia. These findings suggest that CB2r may closely relate the immune system and the brain circuits regulating inflammation, mood, and cognitive functions. Therefore, we review the studies that may help elucidate the molecular bases of CB2r in regulating inflammation in different brain cells and its role in the pathophysiology of psychiatric and neurodegenerative disorders.
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Affiliation(s)
- Alvaro Morcuende
- Instituto de Neurociencias, Universidad Miguel Hernández-Consejo Superior de Investigaciones Científicas (CSIC), Alicante, Spain
| | - María Salud García-Gutiérrez
- Instituto de Neurociencias, Universidad Miguel Hernández-Consejo Superior de Investigaciones Científicas (CSIC), Alicante, Spain.,Redes de Investigación Cooperativa Orientada a Resultados en Salud, Red de Investigación en Atención Primaria de Adicciones, Instituto de Salud Carlos III, Ministerio de Ciencia e Innovación (MICINN) and Fondo Europeo de Desarrollo Regional (FEDER), Madrid, Spain.,Instituto de Investigación Sanitaria y Biomédica de Alicante, Alicante, Spain
| | - Simone Tambaro
- Division of Neurogeriatrics, Center for Alzheimer Research, Department of Neurobiology, Care Sciences and Society, Karolinska Institutet, Stockholm, Sweden
| | - Elena Nieto
- Instituto de Neurociencias, Universidad Miguel Hernández-Consejo Superior de Investigaciones Científicas (CSIC), Alicante, Spain
| | - Jorge Manzanares
- Instituto de Neurociencias, Universidad Miguel Hernández-Consejo Superior de Investigaciones Científicas (CSIC), Alicante, Spain.,Redes de Investigación Cooperativa Orientada a Resultados en Salud, Red de Investigación en Atención Primaria de Adicciones, Instituto de Salud Carlos III, Ministerio de Ciencia e Innovación (MICINN) and Fondo Europeo de Desarrollo Regional (FEDER), Madrid, Spain.,Instituto de Investigación Sanitaria y Biomédica de Alicante, Alicante, Spain
| | - Teresa Femenia
- Instituto de Neurociencias, Universidad Miguel Hernández-Consejo Superior de Investigaciones Científicas (CSIC), Alicante, Spain.,Redes de Investigación Cooperativa Orientada a Resultados en Salud, Red de Investigación en Atención Primaria de Adicciones, Instituto de Salud Carlos III, Ministerio de Ciencia e Innovación (MICINN) and Fondo Europeo de Desarrollo Regional (FEDER), Madrid, Spain
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6
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Carbamazepine Restores Neuronal Signaling, Protein Synthesis, and Cognitive Function in a Mouse Model of Fragile X Syndrome. Int J Mol Sci 2020; 21:ijms21239327. [PMID: 33297570 PMCID: PMC7731004 DOI: 10.3390/ijms21239327] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2020] [Revised: 11/19/2020] [Accepted: 12/03/2020] [Indexed: 02/07/2023] Open
Abstract
Fragile X syndrome (FXS) is a leading genetic disorder of intellectual disability caused by the loss of the functional fragile X mental retardation protein (FMRP). To date, there is no efficacious mechanism-based medication for FXS. With regard to potential disease mechanisms in FXS, it is widely accepted that the lack of FMRP causes elevated protein synthesis and deregulation of neuronal signaling. Abnormal enhancement of the ERK½ (extracellular signal-regulated kinase ½) and PI3K-Akt (Phosphoinositide 3 kinase-protein kinase B) signaling pathways has been identified in both FXS patients and FXS mouse models. In this study, we show that carbamazepine, which is an FDA-approved drug and has been mainly used to treat seizure and neuropathic pain, corrects cognitive deficits including passive avoidance and object location memory in FXS mice. Carbamazepine also rescues hyper locomotion and social deficits. At the cellular level, carbamazepine dampens the elevated level of ERK½ and Akt signaling as well as protein synthesis in FXS mouse neurons. Together, these results advocate repurposing carbamazepine for FXS treatment.
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7
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Canclini L, Cal K, Bardier C, Ruiz P, Mercer JA, Calliari A. Calcium triggers the dissociation of myosin-Va from ribosomes in ribonucleoprotein complexes. FEBS Lett 2020; 594:2311-2321. [PMID: 32412091 DOI: 10.1002/1873-3468.13813] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2020] [Revised: 04/29/2020] [Accepted: 04/30/2020] [Indexed: 11/08/2022]
Abstract
The sorting of RNAs to specific regions of the cell for local translation represents an important mechanism directing protein distribution and cell compartmentalization. While significant progress has been made in understanding the mechanisms underlying the transport and localization of mRNAs, the mechanisms governing ribosome mobilization are less well understood. Ribosomes present in the cytoplasm of multiple cell types can form ribonucleoprotein complexes that also contain myosin-Va (Myo5a), a processive, actin-dependent molecular motor. Here, we report that Myo5a can be disassociated from ribosomes when ribonucleoprotein complexes are exposed to calcium, both in vitro and in vivo. We suggest that Myo5a may act as a molecular switch able to anchor or release ribosomes from the actin cytoskeleton in response to intracellular signaling.
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Affiliation(s)
- Lucía Canclini
- Department of Genetics, Instituto de Investigaciones Biológicas 'Clemente Estable' (MEC), Montevideo, Uruguay
| | - Karina Cal
- Department of Biosciences, Facultad de Veterinaria, Universidad de la República (UdelaR), Montevideo, Uruguay
| | - Camila Bardier
- Department of Genetics, Instituto de Investigaciones Biológicas 'Clemente Estable' (MEC), Montevideo, Uruguay
| | - Paul Ruiz
- Department of Biosciences, Facultad de Veterinaria, Universidad de la República (UdelaR), Montevideo, Uruguay
| | | | - Aldo Calliari
- Department of Biosciences, Facultad de Veterinaria, Universidad de la República (UdelaR), Montevideo, Uruguay
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8
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Ding Q, Sethna F, Wu XT, Miao Z, Chen P, Zhang Y, Xiao H, Feng W, Feng Y, Li X, Wang H. Transcriptome signature analysis repurposes trifluoperazine for the treatment of fragile X syndrome in mouse model. Commun Biol 2020; 3:127. [PMID: 32179850 PMCID: PMC7075969 DOI: 10.1038/s42003-020-0833-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Accepted: 02/07/2020] [Indexed: 02/06/2023] Open
Abstract
Fragile X syndrome (FXS) is a prevailing genetic disorder of intellectual disability and autism. There is no efficacious medication for FXS. Through in silico screening with a public database, computational analysis of transcriptome profile in FXS mouse neurons predicts therapeutic value of an FDA-approved drug trifluoperazine. Systemic administration of low-dose trifluoperazine at 0.05 mg/kg attenuates multiple FXS- and autism-related behavioral symptoms. Moreover, computational analysis of transcriptome alteration caused by trifluoperazine suggests a new mechanism of action against PI3K (Phosphatidylinositol-4,5-bisphosphate 3-kinase) activity. Consistently, trifluoperazine suppresses PI3K activity and its down-stream targets Akt (protein kinase B) and S6K1 (S6 kinase 1) in neurons. Further, trifluoperazine normalizes the aberrantly elevated activity of Akt and S6K1 and enhanced protein synthesis in FXS mouse. Together, our data demonstrate a promising value of transcriptome-based computation in identification of therapeutic strategy and repurposing drugs for neurological disorders, and suggest trifluoperazine as a potential treatment for FXS. Qi Ding, Ferzin Sethna et al. perform a computational analysis of the transcriptome profile of Fmr1−/− neurons and identify trifluoperazine as potential therapeutic agent against Fragile X Syndrome. Next, they show that low doses of trifluoperazine ameliorate some of the behavioral and molecular phenotypes present in Fmr1−/− mice.
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Affiliation(s)
- Qi Ding
- Department of Physiology, Michigan State University, East Lansing, USA
| | - Ferzin Sethna
- Genetics Program, Michigan State University, East Lansing, USA
| | - Xue-Ting Wu
- Key Laboratory of Synthetic Biology, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 200032, Shanghai, China
| | - Zhuang Miao
- Genetics Program, Michigan State University, East Lansing, USA
| | - Ping Chen
- Key Laboratory of Synthetic Biology, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 200032, Shanghai, China
| | - Yueqi Zhang
- Department of Physiology, Michigan State University, East Lansing, USA
| | - Hua Xiao
- Department of Physiology, Michigan State University, East Lansing, USA
| | - Wei Feng
- Department of Pharmacology and Chemical Biology, Emory University School of Medicine, Atlanta, GA, 30322, Georgia
| | - Yue Feng
- Department of Pharmacology and Chemical Biology, Emory University School of Medicine, Atlanta, GA, 30322, Georgia
| | - Xuan Li
- Key Laboratory of Synthetic Biology, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 200032, Shanghai, China
| | - Hongbing Wang
- Department of Physiology, Michigan State University, East Lansing, USA. .,Neuroscience Program, Michigan State University, East Lansing, MI, 48824, USA.
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9
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Yamada Y, Prosser RA. Copper in the suprachiasmatic circadian clock: A possible link between multiple circadian oscillators. Eur J Neurosci 2018; 51:47-70. [PMID: 30269387 DOI: 10.1111/ejn.14181] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2018] [Revised: 09/05/2018] [Accepted: 09/17/2018] [Indexed: 01/07/2023]
Abstract
The mammalian circadian clock in the suprachiasmatic nucleus (SCN) is very robust, able to coordinate our daily physiological and behavioral rhythms with exquisite accuracy. Simultaneously, the SCN clock is highly sensitive to environmental timing cues such as the solar cycle. This duality of resiliency and sensitivity may be sustained in part by a complex intertwining of three cellular oscillators: transcription/translation, metabolic/redox, and membrane excitability. We suggest here that one of the links connecting these oscillators may be forged from copper (Cu). Cellular Cu levels are highly regulated in the brain and peripherally, and Cu affects cellular metabolism, redox state, cell signaling, and transcription. We have shown that both Cu chelation and application induce nighttime phase shifts of the SCN clock in vitro and that these treatments affect glutamate, N-methyl-D-aspartate receptor, and associated signaling processes differently. More recently we found that Cu induces mitogen-activated protein kinase-dependent phase shifts, while the mechanisms by which Cu removal induces phase shifts remain unclear. Lastly, we have found that two Cu transporters are expressed in the SCN, and that one of these transporters (ATP7A) exhibits a day/night rhythm. Our results suggest that Cu homeostasis is tightly regulated in the SCN, and that changes in Cu levels may serve as a time cue for the circadian clock. We discuss these findings in light of the existing literature and current models of multiple coupled circadian oscillators in the SCN.
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Affiliation(s)
- Yukihiro Yamada
- Department of Biochemistry & Cellular and Molecular Biology, NeuroNET Research Center, University of Tennessee, Knoxville, Tennessee
| | - Rebecca A Prosser
- Department of Biochemistry & Cellular and Molecular Biology, NeuroNET Research Center, University of Tennessee, Knoxville, Tennessee
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10
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Bonnefond ML, Florent R, Lenoir S, Lambert B, Abeilard E, Giffard F, Louis MH, Elie N, Briand M, Vivien D, Poulain L, Gauduchon P, N'Diaye M. Inhibition of store-operated channels by carboxyamidotriazole sensitizes ovarian carcinoma cells to anti-Bclx L strategies through Mcl-1 down-regulation. Oncotarget 2018; 9:33896-33911. [PMID: 30338034 PMCID: PMC6188062 DOI: 10.18632/oncotarget.26084] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2017] [Accepted: 08/04/2018] [Indexed: 12/22/2022] Open
Abstract
The anti-apoptotic proteins Bcl-xL and Mcl-1 have been identified to play a pivotal role in apoptosis resistance in ovarian cancer and constitute key targets for innovative therapeutic strategies. Although BH3-mimetics (i.e. ABT-737) potently inhibit Bcl-xL activity, targeting Mcl-1 remains a hurdle to the success of these strategies. Calcium signaling is profoundly remodeled during carcinogenesis and was reported to activate the signaling pathway controlling Mcl-1 expression. In this context, we investigated the effect of carboxyamidotriazole (CAI), a calcium channel inhibitor used in clinical trials, on Mcl-1 expression. CAI had an anti-proliferative effect on ovarian carcinoma cell lines and strongly down-regulated Mcl-1 expression. It inhibited store-operated calcium entry (SOCE) and Mcl-1 translation through mTORC1 deactivation. Moreover, it sensitized ovarian carcinoma cells to anti-Bcl-xL strategies as their combination elicited massive apoptosis. Its effect on mTORC1 and Mcl-1 was mimicked by the potent SOCE inhibitor, YM58483, which also triggered apoptosis when combined with ABT-737. As a whole, this study suggests that CAI sensitizes to anti-Bcl-xL strategies via its action on Mcl-1 translation and that modulation of SOCE could extend the therapeutic arsenal for treatment of ovarian carcinoma.
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Affiliation(s)
- Marie-Laure Bonnefond
- Normandie University, UNICAEN, INSERM U1086 ANTICIPE, Interdisciplinary Research Unit for Cancer Prevention and Treatment, BioTICLA Axis, Biology and Innovative Therapeutics for Ovarian Cancers, Caen, France
- UNICANCER, François Baclesse Cancer Center, BioTICLA Laboratory, Caen, France
| | - Romane Florent
- Normandie University, UNICAEN, INSERM U1086 ANTICIPE, Interdisciplinary Research Unit for Cancer Prevention and Treatment, BioTICLA Axis, Biology and Innovative Therapeutics for Ovarian Cancers, Caen, France
- UNICANCER, François Baclesse Cancer Center, BioTICLA Laboratory, Caen, France
| | - Sophie Lenoir
- Normandie University, UNICAEN, INSERM UMR-S 1237, Physiopathologie et Imagerie des Troubles Neurologiques (PhIND), tPA and Neurovascular Disorders Team, Caen, France
| | - Bernard Lambert
- Normandie University, UNICAEN, INSERM U1086 ANTICIPE, Interdisciplinary Research Unit for Cancer Prevention and Treatment, BioTICLA Axis, Biology and Innovative Therapeutics for Ovarian Cancers, Caen, France
- UNICANCER, François Baclesse Cancer Center, BioTICLA Laboratory, Caen, France
- Délégation Régionale de Normandie, CNRS, Caen, France
| | - Edwige Abeilard
- Normandie University, UNICAEN, INSERM U1086 ANTICIPE, Interdisciplinary Research Unit for Cancer Prevention and Treatment, BioTICLA Axis, Biology and Innovative Therapeutics for Ovarian Cancers, Caen, France
- UNICANCER, François Baclesse Cancer Center, BioTICLA Laboratory, Caen, France
| | - Florence Giffard
- Normandie University, UNICAEN, INSERM U1086 ANTICIPE, Interdisciplinary Research Unit for Cancer Prevention and Treatment, BioTICLA Axis, Biology and Innovative Therapeutics for Ovarian Cancers, Caen, France
- UNICANCER, François Baclesse Cancer Center, BioTICLA Laboratory, Caen, France
| | - Marie-Hélène Louis
- Normandie University, UNICAEN, INSERM U1086 ANTICIPE, Interdisciplinary Research Unit for Cancer Prevention and Treatment, BioTICLA Axis, Biology and Innovative Therapeutics for Ovarian Cancers, Caen, France
- UNICANCER, François Baclesse Cancer Center, BioTICLA Laboratory, Caen, France
| | - Nicolas Elie
- Normandie University, UNICAEN, INSERM U1086 ANTICIPE, Interdisciplinary Research Unit for Cancer Prevention and Treatment, BioTICLA Axis, Biology and Innovative Therapeutics for Ovarian Cancers, Caen, France
- Normandie University, UNICAEN, Centre de Microscopie Appliqué à la Biologie, CMabio3, Structure Fédérative 4206 ICORE, Caen, France
| | - Mélanie Briand
- Normandie University, UNICAEN, INSERM U1086 ANTICIPE, Interdisciplinary Research Unit for Cancer Prevention and Treatment, BioTICLA Axis, Biology and Innovative Therapeutics for Ovarian Cancers, Caen, France
- UNICANCER, François Baclesse Cancer Center, BioTICLA Laboratory, Caen, France
- Centre de Ressources Biologiques, OvaRessources, François Baclesse Cancer Center, Caen, France
| | - Denis Vivien
- Normandie University, UNICAEN, INSERM UMR-S 1237, Physiopathologie et Imagerie des Troubles Neurologiques (PhIND), tPA and Neurovascular Disorders Team, Caen, France
| | - Laurent Poulain
- Normandie University, UNICAEN, INSERM U1086 ANTICIPE, Interdisciplinary Research Unit for Cancer Prevention and Treatment, BioTICLA Axis, Biology and Innovative Therapeutics for Ovarian Cancers, Caen, France
- UNICANCER, François Baclesse Cancer Center, BioTICLA Laboratory, Caen, France
| | - Pascal Gauduchon
- Normandie University, UNICAEN, INSERM U1086 ANTICIPE, Interdisciplinary Research Unit for Cancer Prevention and Treatment, BioTICLA Axis, Biology and Innovative Therapeutics for Ovarian Cancers, Caen, France
- UNICANCER, François Baclesse Cancer Center, BioTICLA Laboratory, Caen, France
| | - Monique N'Diaye
- Normandie University, UNICAEN, INSERM U1086 ANTICIPE, Interdisciplinary Research Unit for Cancer Prevention and Treatment, BioTICLA Axis, Biology and Innovative Therapeutics for Ovarian Cancers, Caen, France
- UNICANCER, François Baclesse Cancer Center, BioTICLA Laboratory, Caen, France
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11
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Salehpour M, Khodagholi F, Zeinaddini Meymand A, Nourshahi M, Ashabi G. Exercise training with concomitant nitric oxide synthase inhibition improved anxiogenic behavior, spatial cognition, and BDNF/P70S6 kinase activation in 20-month-old rats. Appl Physiol Nutr Metab 2017; 43:45-53. [PMID: 28854337 DOI: 10.1139/apnm-2017-0313] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
This study aimed to investigate the effect of exercise and nitric oxide synthase (NOS) inhibition on memory, anxiety, and protein levels of brain-derived neurotrophic factor (BDNF) and P70S6 kinase (P70S6K). Twenty-month-old rats were divided into 6 groups: a control group, 2 groups treated with l-nitro-arginine methyl ester (L-NAME) (25 or 100 mg/kg) for 63 days, 2 groups treated with L-NAME (25 or 100 mg/kg) for 63 days plus 2 months of exercise, and 1 group treated with exercise. Behavioral tests were conducted to determine the anxiolytic and memory-improving role of exercise and NOS inhibition. BDNF, P70S6K, and cleaved caspase-3 protein levels in the hippocampus and prefrontal cortex were evaluated by Western blotting. Exercise and L-NAME (25 mg/kg) or their combination had an anxiolytic effect and improved spatial memory in old rats compared with the control or exercised group, respectively. Exercise and treatment with a low dose of L-NAME (25 mg/kg) each increased BDNF and P70S6K in the hippocampus and prefrontal cortex compared with levels in control rats. In comparison with exercise alone, co-treatment with exercise and a low dose of L-NAME (25 mg/kg) also increased BDNF and P70S6K in the hippocampus. The neuronal level of cleaved caspase-3 was reduced in the L-NAME (25 mg/kg) + exercise group compared with the exercised group. The L-NAME (100 mg/kg) + exercise treatment had no positive behavioral or molecular effects compared with exercise alone. The protective role of NOS inhibition and aerobic exercise against aging is probably modulated via BDNF and P70S6K in the brain.
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Affiliation(s)
- Mojtaba Salehpour
- a Department of Sport Physiology, Faculty of Sport Sciences, Shahid Rajaee Teacher Training University, PO box 16875-163, Tehran, Iran
| | - Fariba Khodagholi
- b NeuroBiology Research Center, Shahid Beheshti University of Medical Sciences, PO box 19615-1178, Tehran, Iran
| | - Arman Zeinaddini Meymand
- c Neuroscience Research Center, Shahid Beheshti University of Medical Sciences, PO box 19615-1178, Tehran, Iran
| | - Maryam Nourshahi
- d Department of Sport Physiology, Faculty of Physical Education and Sport Sciences, Shahid Beheshti University, PO box 19839-6113, Tehran, Iran
| | - Ghorbangol Ashabi
- e Department of Physiology, Faculty of Medicine, Tehran University of Medical Sciences, PO box 141761-3151, Tehran, Iran
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12
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Brain-Derived Neurotrophic Factor Increases Synaptic Protein Levels via the MAPK/Erk Signaling Pathway and Nrf2/Trx Axis Following the Transplantation of Neural Stem Cells in a Rat Model of Traumatic Brain Injury. Neurochem Res 2017; 42:3073-3083. [PMID: 28780733 DOI: 10.1007/s11064-017-2340-7] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2017] [Revised: 06/05/2017] [Accepted: 06/20/2017] [Indexed: 01/28/2023]
Abstract
Brain-derived neurotrophic factor (BDNF) plays an important role in promoting the growth, differentiation, survival and synaptic stability of neurons. Presently, the transplantation of neural stem cells (NSCs) is known to induce neural repair to some extent after injury or disease. In this study, to investigate whether NSCs genetically modified to encode the BDNF gene (BDNF/NSCs) would further enhance synaptogenesis, BDNF/NSCs or naive NSCs were directly engrafted into lesions in a rat model of traumatic brain injury (TBI). Immunohistochemistry, western blotting and RT-PCR were performed to detect synaptic proteins, BDNF-TrkB and its downstream signaling pathways, at 1, 2, 3 or 4 weeks after transplantation. Our results showed that BDNF significantly increased the expression levels of the TrkB receptor gene and the phosphorylation of the TrkB protein in the lesions. The expression levels of Ras, phosphorylated Erk1/2 and postsynaptic density protein-95 were elevated in the BDNF/NSCs-transplanted groups compared with those in the NSCs-transplanted groups throughout the experimental period. Moreover, the nuclear factor (erythroid-derived 2)-like 2/Thioredoxin (Nrf2/Trx) axis, which is a specific therapeutic target for the treatment of injury or cell death, was upregulated by BDNF overexpression. Therefore, we determined that the increased synaptic proteins level implicated in synaptogenesis might be associated with the activation of the MAPK/Erk1/2 signaling pathway and the upregulation of the antioxidant agent Trx modified by BDNF-TrkB following the BDNF/NSCs transplantation after TBI.
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13
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Li RJ, Xu J, Fu C, Zhang J, Zheng YG, Jia H, Liu JO. Regulation of mTORC1 by lysosomal calcium and calmodulin. eLife 2016; 5. [PMID: 27787197 PMCID: PMC5106211 DOI: 10.7554/elife.19360] [Citation(s) in RCA: 100] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2016] [Accepted: 10/26/2016] [Indexed: 11/13/2022] Open
Abstract
Blockade of lysosomal calcium release due to lysosomal lipid accumulation has been shown to inhibit mTORC1 signaling. However, the mechanism by which lysosomal calcium regulates mTORC1 has remained undefined. Herein we report that proper lysosomal calcium release through the calcium channel TRPML1 is required for mTORC1 activation. TRPML1 depletion inhibits mTORC1 activity, while overexpression or pharmacologic activation of TRPML1 has the opposite effect. Lysosomal calcium activates mTORC1 by inducing association of calmodulin (CaM) with mTOR. Blocking the interaction between mTOR and CaM by antagonists of CaM significantly inhibits mTORC1 activity. Moreover, CaM is capable of stimulating the kinase activity of mTORC1 in a calcium-dependent manner in vitro. These results reveal that mTOR is a new type of CaM-dependent kinase, and TRPML1, lysosomal calcium and CaM play essential regulatory roles in the mTORC1 signaling pathway.
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Affiliation(s)
- Ruo-Jing Li
- Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, United States.,The SJ Yan and HJ Mao Laboratory of Chemical Biology, Johns Hopkins University School of Medicine, Baltimore, United States
| | - Jing Xu
- Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, United States.,The SJ Yan and HJ Mao Laboratory of Chemical Biology, Johns Hopkins University School of Medicine, Baltimore, United States.,Eli Lilly and Company, Indianapolis, United States
| | - Chenglai Fu
- The Solomon H Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, United States
| | - Jing Zhang
- Department of Pharmaceutical and Biomedical Sciences, College of Pharmacy, The University of Georgia, Athens, United States
| | - Yujun George Zheng
- Department of Pharmaceutical and Biomedical Sciences, College of Pharmacy, The University of Georgia, Athens, United States
| | - Hao Jia
- Department of Physiology, Johns Hopkins University School of Medicine, Baltimore, United States
| | - Jun O Liu
- Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, United States.,The SJ Yan and HJ Mao Laboratory of Chemical Biology, Johns Hopkins University School of Medicine, Baltimore, United States.,Department of Oncology, Johns Hopkins University School of Medicine, Baltimore, United States
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14
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Andreani T, Tong M, Gundogan F, Silbermann E, de la Monte SM. Differential Effects of 3rd Trimester-Equivalent Binge Ethanol and Tobacco-Specific Nitrosamine Ketone Exposures on Brain Insulin Signaling in Adolescence. JOURNAL OF DIABETES AND RELATED DISORDERS 2016; 1:105. [PMID: 29242853 PMCID: PMC5726776] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
BACKGROUND Fetal alcohol spectrum disorder (FASD) is associated with impairments in insulin and insulin-like growth factor (IGF) signaling through Akt pathways and altered expression of neuro-glial proteins needed for structural and functional integrity of the brain. However, alcohol abuse correlates with smoking, and tobacco smoke contains 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK), which like other nitrosamines, impairs insulin and IGF signaling. HYPOTHESIS NNK exposure can serve as a co-factor in mediating long-term neuro-developmental abnormalities associated with FASD. DESIGN Long Evans rat pups were IP administered ethanol (2 g/kg) on postnatal days (P) 2, 4, 6 and/or NNK (2 mg/kg) on P3, P5, and P7, simulating third trimester human exposures. Temporal lobes from P30 rats (young adolescent) were used to measure signaling through the insulin/IGF-1/Akt pathways by multiplex ELISAs, and expression of neuroglial proteins by duplex ELISAs. RESULTS Ethanol, NNK, and ethanol + NNK exposures significantly inhibited insulin receptor tyrosine phosphorylation, and IRS-1 and myelin-associated glycoprotein expression. However, the major long-term adverse effects on Akt pathway downstream signaling and its targeted proteins including choline acetyltransferase, Tau, pTau, ubiquitin, and aspartate-β-hydroxylase were due to NNK rather than ethanol. CONCLUSION Alcohol and tobacco exposures can both contribute to long-term brain abnormalities currently regarded fetal ethanol effects. However, the findings suggest that many of the adverse effects on brain function are attributable to smoking, including impairments in signaling through survival and metabolic pathways, and altered expression of genes that regulate myelin synthesis, maturation and integrity and synaptic plasticity. Therefore, public health measures should address both substances of abuse to prevent "FASD".
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Affiliation(s)
- Tomas Andreani
- Department of Medicine, Division of Gastroenterology, and the Liver
Research Center Rhode Island Hospital, Providence, RI, USA
| | - Ming Tong
- Department of Medicine, Division of Gastroenterology, and the Liver
Research Center Rhode Island Hospital, Providence, RI, USA
- Warren Alpert Medical School of Brown University, Providence, RI,
USA
| | - Fusun Gundogan
- Department of Pathology, Women and Infants Hospital of Rhode Island,
Providence, RI, USA
- Warren Alpert Medical School of Brown University, Providence, RI,
USA
| | | | - Suzanne M. de la Monte
- Department of Medicine, Division of Gastroenterology, and the Liver
Research Center Rhode Island Hospital, Providence, RI, USA
- Departments of Pathology and Neurology, and the Division of
Neuropathology, Rhode Island Hospital, Providence, RI, USA
- Warren Alpert Medical School of Brown University, Providence, RI,
USA
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15
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Reinstating aberrant mTORC1 activity in Huntington's disease mice improves disease phenotypes. Neuron 2014; 85:303-15. [PMID: 25556834 DOI: 10.1016/j.neuron.2014.12.019] [Citation(s) in RCA: 120] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/01/2014] [Indexed: 12/28/2022]
Abstract
Huntington's disease (HD) is caused by a polyglutamine tract expansion in huntingtin (HTT). Despite HTTs ubiquitous expression, there is early and robust vulnerability in striatum, the cause of which is poorly understood. Here, we provide evidence that impaired striatal mTORC1 activity underlies varied metabolic and degenerative phenotypes in HD brain and show that introducing the constitutively active form of the mTORC1 regulator, Rheb, into HD mouse brain, alleviates mitochondrial dysfunction, aberrant cholesterol homeostasis, striatal atrophy, impaired dopamine signaling, and increases autophagy. We also find that the expression of Rhes, a striatum-enriched mTOR activator, is reduced in HD patient and mouse brain and that exogenous addition of Rhes alleviates motor deficits and improves brain pathology in HD mice. Our combined work indicates that impaired Rhes/mTORC1 activity in HD brain may underlie the notable striatal susceptibility and thus presents a promising therapeutic target for HD therapy.
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Briz V, Baudry M. Estrogen Regulates Protein Synthesis and Actin Polymerization in Hippocampal Neurons through Different Molecular Mechanisms. Front Endocrinol (Lausanne) 2014; 5:22. [PMID: 24611062 PMCID: PMC3933789 DOI: 10.3389/fendo.2014.00022] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/19/2013] [Accepted: 02/13/2014] [Indexed: 12/21/2022] Open
Abstract
Estrogen rapidly modulates hippocampal synaptic plasticity by activating selective membrane-associated receptors. Reorganization of the actin cytoskeleton and stimulation of mammalian target of rapamycin (mTOR)-mediated protein synthesis are two major events required for the consolidation of hippocampal long-term potentiation and memory. Estradiol regulates synaptic plasticity by interacting with both processes, but the underlying molecular mechanisms are not yet fully understood. Here, we used acute rat hippocampal slices to analyze the mechanisms underlying rapid changes in mTOR activity and actin polymerization elicited by estradiol. Estradiol-induced mTOR phosphorylation was preceded by rapid and transient activation of both extracellular signal-regulated kinase (ERK) and protein kinase B (Akt) and by phosphatase and tensin homolog (PTEN) degradation. These effects were prevented by calpain and ERK inhibitors. Estradiol-induced mTOR stimulation did not require activation of classical estrogen receptors (ER), as specific ERα and ERβ agonists (PPT and DPN, respectively) failed to mimic this effect, and ER antagonists could not block it. Estradiol rapidly activated both RhoA and p21-activated kinase (PAK). Furthermore, a specific inhibitor of RhoA kinase (ROCK), H1152, and a potent and specific PAK inhibitor, PF-3758309, blocked estradiol-induced cofilin phosphorylation and actin polymerization. ER antagonists also blocked these effects of estrogen. Consistently, both PPT and DPN stimulated PAK and cofilin phosphorylation as well as actin polymerization. Finally, the effects of estradiol on actin polymerization were insensitive to protein synthesis inhibitors, but its stimulation of mTOR activity was impaired by latrunculin A, a drug that disrupts actin filaments. Taken together, our results indicate that estradiol regulates local protein synthesis and cytoskeletal reorganization via different molecular mechanisms and signaling pathways.
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Affiliation(s)
- Victor Briz
- Graduate College of Biomedical Sciences, Western University of Health Sciences, Pomona, CA, USA
| | - Michel Baudry
- Graduate College of Biomedical Sciences, Western University of Health Sciences, Pomona, CA, USA
- *Correspondence: Michel Baudry, Graduate College of Biomedical Sciences, Western University of Health Sciences, NSC, Room 102C, 309 E. 2nd Street, Pomona, CA 91766-1854, USA e-mail:
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17
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Sethna F, Moon C, Wang H. From FMRP function to potential therapies for fragile X syndrome. Neurochem Res 2013; 39:1016-31. [PMID: 24346713 DOI: 10.1007/s11064-013-1229-3] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2013] [Revised: 12/03/2013] [Accepted: 12/12/2013] [Indexed: 12/12/2022]
Abstract
Fragile X syndrome (FXS) is caused by mutations in the fragile X mental retardation 1 (FMR1) gene. Most FXS cases occur due to the expansion of the CGG trinucleotide repeats in the 5' un-translated region of FMR1, which leads to hypermethylation and in turn silences the expression of FMRP (fragile X mental retardation protein). Numerous studies have demonstrated that FMRP interacts with both coding and non-coding RNAs and represses protein synthesis at dendritic and synaptic locations. In the absence of FMRP, the basal protein translation is enhanced and not responsive to neuronal stimulation. The altered protein translation may contribute to functional abnormalities in certain aspects of synaptic plasticity and intracellular signaling triggered by Gq-coupled receptors. This review focuses on the current understanding of FMRP function and potential therapeutic strategies that are mainly based on the manipulation of FMRP targets and knowledge gained from FXS pathophysiology.
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Affiliation(s)
- Ferzin Sethna
- Genetics Program, Michigan State University, East Lansing, MI, 48824, USA
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18
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Westerholz S, de Lima AD, Voigt T. Thyroid hormone-dependent development of early cortical networks: temporal specificity and the contribution of trkB and mTOR pathways. Front Cell Neurosci 2013; 7:121. [PMID: 23964198 PMCID: PMC3734363 DOI: 10.3389/fncel.2013.00121] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2013] [Accepted: 07/10/2013] [Indexed: 11/17/2022] Open
Abstract
Early in neocortical network development, triiodothyronine (T3) promotes GABAergic neurons' population increase, their somatic growth and the formation of GABAergic synapses. In the presence of T3, GABAergic interneurons form longer axons and conspicuous axonal arborizations, with an increased number of putative synaptic boutons. Here we show that the increased GABAergic axonal growth is positively correlated with the proximity to non-GABAergic neurons (non-GABA). A differential innervation emerges from a T3-dependent decrease of axonal length in fields with low density of neuronal cell bodies, combined with an increased bouton formation in fields with high density of neuronal somata. T3 addition to deprived networks after the first 2 weeks of development did not rescue deficits in the GABAergic synaptic bouton distribution, or in the frequency and duration of spontaneous bursts. During the critical 2-week-period, GABAergic signaling is depolarizing as revealed by calcium imaging experiments. Interestingly, T3 enhanced the expression of the potassium-chloride cotransporter 2 (KCC2), and accelerated the developmental shift from depolarizing to hyperpolarizing GABAergic signaling in non-GABA. The T3-related increase of spontaneous network activity was remarkably reduced after blockade of either tropomyosin-receptor kinase B (trkB) or mammalian target of rapamycin (mTOR) pathways. T3-dependent increase in GABAergic neurons' soma size was mediated mainly by mTOR signaling. Conversely, the T3-dependent selective increase of GABAergic boutons near non-GABAergic cell bodies is mediated by trkB signaling only. Both trkB and mTOR signaling mediate T3-dependent reduction of the GABAergic axon extension. The circuitry context is relevant for the interaction between T3 and trkB signaling, but not for the interactions between T3 and mTOR signaling.
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Affiliation(s)
- Sören Westerholz
- Institute of Physiology, Otto-von-Guericke University Magdeburg, Germany
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19
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Calpain-2-mediated PTEN degradation contributes to BDNF-induced stimulation of dendritic protein synthesis. J Neurosci 2013; 33:4317-28. [PMID: 23467348 DOI: 10.1523/jneurosci.4907-12.2013] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Memory consolidation has been suggested to be protein synthesis dependent. Previous data indicate that BDNF-induced dendritic protein synthesis is a key event in memory formation through activation of the mammalian target of rapamycin (mTOR) pathway. BDNF also activates calpain, a calcium-dependent cysteine protease, which has been shown to play a critical role in learning and memory. This study was therefore directed at testing the hypothesis that calpain activity is required for BDNF-stimulated local protein synthesis, and at identifying the underlying molecular mechanism. In rat hippocampal slices, cortical synaptoneurosomes, and cultured neurons, BDNF-induced mTOR pathway activation and protein translation were blocked by calpain inhibition. BDNF treatment rapidly reduced levels of hamartin and tuberin, negative regulators of mTOR, in a calpain-dependent manner. Treatment of brain homogenates with purified calpain-1 and calpain-2 truncated both proteins. BDNF treatment increased phosphorylation of both Akt and ERK, but only the effect on Akt was blocked by calpain inhibition. Levels of phosphatase and tensin homolog deleted on chromosome 10 (PTEN), a phosphatase that inactivates Akt, were decreased following BDNF treatment, and calpain inhibition reversed this effect. Calpain-2, but not calpain-1, treatment of brain homogenates resulted in PTEN degradation. In cultured cortical neurons, knockdown of calpain-2, but not calpain-1, by small interfering RNA completely suppressed the effect of BDNF on mTOR activation. Our results reveal a critical role for calpain-2 in BDNF-induced mTOR signaling and dendritic protein synthesis via PTEN, hamartin, and tuberin degradation. This mechanism therefore provides a link between proteolysis and protein synthesis that might contribute to synaptic plasticity.
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20
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Liu L, Martin R, Chan C. Palmitate-activated astrocytes via serine palmitoyltransferase increase BACE1 in primary neurons by sphingomyelinases. Neurobiol Aging 2013; 34:540-50. [PMID: 22727944 PMCID: PMC3459302 DOI: 10.1016/j.neurobiolaging.2012.05.017] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2011] [Revised: 04/27/2012] [Accepted: 05/26/2012] [Indexed: 10/28/2022]
Abstract
Astrocytes play a critical role in neurodegenerative diseases, including Alzheimer's disease (AD). Previously, we showed that saturated free fatty acid, palmitic acid (PA), upregulates β-site amyloid precursor protein-cleaving enzyme 1 (BACE1) level and amyloidogenesis in primary rat neurons mediated by astrocytes. However, the molecular mechanisms by which conditioned media from PA-treated astrocytes upregulates BACE1 level in neurons are unknown. This study demonstrates that serine palmitoyltransferase (SPT) in the astrocytes increases ceramide levels, which enhances the release of cytokines that mediate the activation of neural and acidic sphingomyelinase (SMase) in the neurons, to propagate the deleterious effects of PA (i.e., BACE1 upregulation). In support of the relevance of SPT in AD, our laboratory recently measured and found SPT levels to be significantly upregulated in AD brains as compared with controls. Cytokines, namely tumor necrosis factor-α and interleukin-1β, released into the conditioned media of PA-treated astrocytes activate neural and acidic SMase in the neurons. Neutralizing the cytokines in the PA-treated astrocyte conditioned media reduced BACE1 upregulation. However, inhibiting SPT in the astrocytes decreased the levels of both tumor necrosis factor-α and interleukin-1β in the conditioned media, which in turn reduced the SMase activities and BACE1 level in primary neurons. Thus, our results suggest that the activation of the astrocytes by PA is mediated by SPT, and the activated astrocytes increases BACE1 level in the neurons; the latter is mediate by the SMases.
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Affiliation(s)
- Li Liu
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI 48824
| | - Rebecca Martin
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI 48824
| | - Christina Chan
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI 48824
- Department of Chemical Engineering and Materials Science, Michigan State University, East Lansing, MI 48824
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Abstract
Over this past decade, macroautophagy has gained prominence in the field of adult-onset neurodegeneration: from sporadic disorders such as Alzheimer's and Parkinson's disease, to genetic disorders such as Huntington's disease and frontotemporal dementia, the influence of this fundamental pathway has become an important topic of discussion. While there has been particular emphasis on the potential benefits of macroautophagy, there is growing literature that also suggests that macroautophagy contributes towards neurotoxicity. In this review, we discuss the molecular mechanism of macroautophagy and the currently available pharmacological tools, with special emphasis on mammalian macroautophagy in adult brain. Studies indicate that neuronal context strongly influences the role macroautophagy plays in maintaining cellular health, reflecting an ongoing need for better understanding of how macroautophagic regulation is achieved in the heavily differentiated and polarized neurons if we are to effectively manipulate it to treat neurodegenerative disease.
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22
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Swanger SA, Bassell GJ. Dendritic protein synthesis in the normal and diseased brain. Neuroscience 2012; 232:106-27. [PMID: 23262237 DOI: 10.1016/j.neuroscience.2012.12.003] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2012] [Revised: 11/21/2012] [Accepted: 12/01/2012] [Indexed: 01/25/2023]
Abstract
Synaptic activity is a spatially limited process that requires a precise, yet dynamic, complement of proteins within the synaptic micro-domain. The maintenance and regulation of these synaptic proteins is regulated, in part, by local mRNA translation in dendrites. Protein synthesis within the postsynaptic compartment allows neurons tight spatial and temporal control of synaptic protein expression, which is critical for proper functioning of synapses and neural circuits. In this review, we discuss the identity of proteins synthesized within dendrites, the receptor-mediated mechanisms regulating their synthesis, and the possible roles for these locally synthesized proteins. We also explore how our current understanding of dendritic protein synthesis in the hippocampus can be applied to new brain regions and to understanding the pathological mechanisms underlying varied neurological diseases.
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Affiliation(s)
- S A Swanger
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - G J Bassell
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA 30322, USA; Department of Neurology, Emory University School of Medicine, Atlanta, GA 30322, USA.
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23
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Gross C, Berry-Kravis EM, Bassell GJ. Therapeutic strategies in fragile X syndrome: dysregulated mGluR signaling and beyond. Neuropsychopharmacology 2012; 37:178-95. [PMID: 21796106 PMCID: PMC3238060 DOI: 10.1038/npp.2011.137] [Citation(s) in RCA: 87] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/14/2011] [Revised: 06/17/2011] [Accepted: 06/17/2011] [Indexed: 01/11/2023]
Abstract
Fragile X syndrome (FXS) is an inherited neurodevelopmental disease caused by loss of function of the fragile X mental retardation protein (FMRP). In the absence of FMRP, signaling through group 1 metabotropic glutamate receptors is elevated and insensitive to stimulation, which may underlie many of the neurological and neuropsychiatric features of FXS. Treatment of FXS animal models with negative allosteric modulators of these receptors and preliminary clinical trials in human patients support the hypothesis that metabotropic glutamate receptor signaling is a valuable therapeutic target in FXS. However, recent research has also shown that FMRP may regulate diverse aspects of neuronal signaling downstream of several cell surface receptors, suggesting a possible new route to more direct disease-targeted therapies. Here, we summarize promising recent advances in basic research identifying and testing novel therapeutic strategies in FXS models, and evaluate their potential therapeutic benefits. We provide an overview of recent and ongoing clinical trials motivated by some of these findings, and discuss the challenges for both basic science and clinical applications in the continued development of effective disease mechanism-targeted therapies for FXS.
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Affiliation(s)
- Christina Gross
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA, USA
| | - Elizabeth M Berry-Kravis
- Departments of Pediatrics, Neurology, and Biochemistry, Rush University Medical Center, Chicago, IL, USA
| | - Gary J Bassell
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA, USA
- Department of Neurology, Emory University School of Medicine, Atlanta, GA, USA
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24
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Regulation of brain-derived neurotrophic factor exon IV transcription through calcium responsive elements in cortical neurons. PLoS One 2011; 6:e28441. [PMID: 22174809 PMCID: PMC3235121 DOI: 10.1371/journal.pone.0028441] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2011] [Accepted: 11/08/2011] [Indexed: 01/09/2023] Open
Abstract
Activity-dependent transcription of brain-derived neurotrophic factor (BDNF) has been studied as an important model to elucidate the mechanisms underlying numerous aspects of neuroplasticity. It has been extensively emphasized that Ca2+ influx through different routes may have significantly different effects on BDNF transcription. Here, we examined the regulatory property of the major calcium responsive elements (CaRE) in BDNF promoter IV in cultured rat cortical neurons. BDNF promoter IV, as well as CaRE1 and CaRE3, was significantly activated by Ca2+ influx through L-type voltage-gated calcium channel (L-VGCC) or NMDA receptor (NMDAR). However, the L-VGCC- and NMDAR-mediated activation of CaRE was differentially regulated by different Ca2+-stimulated protein kinases. Specifically, PKA, CaMKI, and CaMKIV activity were required for L-VGCC-, but not NMDAR-mediated CaRE1 activation. CaMKI activity was required for NMDAR- but not L-VGCC-mediated CaRE3 activation. Surprisingly, the activation of CaRF, a previously identified transcription factor for CaRE1, was stimulated via L-VGCC but not NMDAR, and required MEK, PI3K and CaMKII activity. These results suggest a new working model that activity-dependent BDNF IV up-regulation may be coordinately mediated by CaRE1 and CaRE3 activity, which show different responses to Ca2+-stimulated kinases. Our data also explain how the individual cis-element in BDNF promoter is distinctively coupled to different Ca2+ routes.
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