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Verma H, Kaur S, Kaur S, Gangwar P, Dhiman M, Mantha AK. Role of Cytoskeletal Elements in Regulation of Synaptic Functions: Implications Toward Alzheimer's Disease and Phytochemicals-Based Interventions. Mol Neurobiol 2024:10.1007/s12035-024-04053-3. [PMID: 38491338 DOI: 10.1007/s12035-024-04053-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2023] [Accepted: 02/13/2024] [Indexed: 03/18/2024]
Abstract
Alzheimer's disease (AD), a multifactorial disease, is characterized by the accumulation of neurofibrillary tangles (NFTs) and amyloid beta (Aβ) plaques. AD is triggered via several factors like alteration in cytoskeletal proteins, a mutation in presenilin 1 (PSEN1), presenilin 2 (PSEN2), amyloid precursor protein (APP), and post-translational modifications (PTMs) in the cytoskeletal elements. Owing to the major structural and functional role of cytoskeletal elements, like the organization of axon initial segmentation, dendritic spines, synaptic regulation, and delivery of cargo at the synapse; modulation of these elements plays an important role in AD pathogenesis; like Tau is a microtubule-associated protein that stabilizes the microtubules, and it also causes inhibition of nucleo-cytoplasmic transportation by disrupting the integrity of nuclear pore complex. One of the major cytoskeletal elements, actin and its dynamics, regulate the dendritic spine structure and functions; impairments have been documented towards learning and memory defects. The second major constituent of these cytoskeletal elements, microtubules, are necessary for the delivery of the cargo, like ion channels and receptors at the synaptic membranes, whereas actin-binding protein, i.e., Cofilin's activation form rod-like structures, is involved in the formation of paired helical filaments (PHFs) observed in AD. Also, the glial cells rely on their cytoskeleton to maintain synaptic functionality. Thus, making cytoskeletal elements and their regulation in synaptic structure and function as an important aspect to be focused for better management and targeting AD pathology. This review advocates exploring phytochemicals and Ayurvedic plant extracts against AD by elucidating their neuroprotective mechanisms involving cytoskeletal modulation and enhancing synaptic plasticity. However, challenges include their limited bioavailability due to the poor solubility and the limited potential to cross the blood-brain barrier (BBB), emphasizing the need for targeted strategies to improve therapeutic efficacy.
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Affiliation(s)
- Harkomal Verma
- Department of Zoology, School of Basic Sciences, Central University of Punjab, Village Ghudda, VPO - Ghudda, Bathinda, 151 401, Punjab, India
| | - Sharanjot Kaur
- Department of Microbiology, School of Basic Sciences, Central University of Punjab, Village Ghudda, Bathinda, Punjab, India
| | - Sukhchain Kaur
- Department of Microbiology, School of Basic Sciences, Central University of Punjab, Village Ghudda, Bathinda, Punjab, India
| | - Prabhakar Gangwar
- Department of Zoology, School of Basic Sciences, Central University of Punjab, Village Ghudda, VPO - Ghudda, Bathinda, 151 401, Punjab, India
| | - Monisha Dhiman
- Department of Microbiology, School of Basic Sciences, Central University of Punjab, Village Ghudda, Bathinda, Punjab, India
| | - Anil Kumar Mantha
- Department of Zoology, School of Basic Sciences, Central University of Punjab, Village Ghudda, VPO - Ghudda, Bathinda, 151 401, Punjab, India.
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2
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Toyoda S, Handa T, Yong H, Takahashi H, Shiwaku H. IMPDH2 forms spots at branching sites and distal ends of astrocyte stem processes. Genes Cells 2024; 29:150-158. [PMID: 38009721 DOI: 10.1111/gtc.13088] [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: 10/10/2023] [Revised: 11/12/2023] [Accepted: 11/15/2023] [Indexed: 11/29/2023]
Abstract
Inosine monophosphate dehydrogenase (IMPDH) is a rate-limiting enzyme in the de novo GTP biosynthesis pathway. Recent studies suggest that IMPDH2, an isoform of IMPDH, can localize to specific subcellular compartments under certain conditions and regulate site-specific GTP availability and small GTPase activity in invasive cancer cells. However, it is unclear whether IMPDH2 plays a site-specific regulatory role in subcellular functions in healthy cells. In this study, we focused on brain cells and examined the localization pattern of IMPDH2. We discovered that IMPDH2 forms localized spots in the astrocytes of the adult mouse hippocampus. Further analysis of spot distribution in primary astrocyte cultures revealed that IMPDH2 spots are predominantly localized on branching sites and distal ends of astrocyte stem processes. Our findings suggest a potential unidentified role for IMPDH2 and GTP synthesis specifically at specialized nodes of astrocyte branches.
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Affiliation(s)
- Saori Toyoda
- Department of Psychiatry and Behavioral Sciences, Tokyo Medical and Dental University Graduate School, Tokyo, Japan
| | - Takehisa Handa
- Department of Psychiatry and Behavioral Sciences, Tokyo Medical and Dental University Graduate School, Tokyo, Japan
| | - Huang Yong
- Department of Neuropathology, Medical Research Institute and Center for Brain Integration Research, Tokyo Medical and Dental University, Tokyo, Japan
| | - Hidehiko Takahashi
- Department of Psychiatry and Behavioral Sciences, Tokyo Medical and Dental University Graduate School, Tokyo, Japan
| | - Hiroki Shiwaku
- Department of Psychiatry and Behavioral Sciences, Tokyo Medical and Dental University Graduate School, Tokyo, Japan
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3
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Han KA, Ko J. Orchestration of synaptic functions by WAVE regulatory complex-mediated actin reorganization. Exp Mol Med 2023; 55:1065-1075. [PMID: 37258575 PMCID: PMC10318009 DOI: 10.1038/s12276-023-01004-1] [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: 02/07/2023] [Revised: 03/13/2023] [Accepted: 03/13/2023] [Indexed: 06/02/2023] Open
Abstract
The WAVE regulatory complex (WRC), composed of five components-Cyfip1/Sra1, WAVE/Scar, Abi, Nap1/Nckap1, and Brk1/HSPC300-is essential for proper actin cytoskeletal dynamics and remodeling in eukaryotic cells, likely by matching various patterned signals to Arp2/3-mediated actin nucleation. Accumulating evidence from recent studies has revealed diverse functions of the WRC in neurons, demonstrating its crucial role in dictating the assembly of molecular complexes for the patterning of various trans-synaptic signals. In this review, we discuss recent exciting findings on the physiological role of the WRC in regulating synaptic properties and highlight the involvement of WRC dysfunction in various brain disorders.
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Affiliation(s)
- Kyung Ah Han
- Department of Brain Sciences, Daegu Gyeongbuk Institute of Science and Technology (DGIST), 333 Techno Jungangdae-Ro, Hyeonpoong-Eup, Dalseong-Gun, Daegu, 42988, Korea
- Center for Synapse Diversity and Specificity, DGIST, Daegu, 42988, Korea
| | - Jaewon Ko
- Department of Brain Sciences, Daegu Gyeongbuk Institute of Science and Technology (DGIST), 333 Techno Jungangdae-Ro, Hyeonpoong-Eup, Dalseong-Gun, Daegu, 42988, Korea.
- Center for Synapse Diversity and Specificity, DGIST, Daegu, 42988, Korea.
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4
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Han JX, Wen CX, Sun R, Tang MY, Li XM, Lian H. The dorsal hippocampal CA3 regulates spatial reference memory through the CtBP2/GluR2 pathway. FASEB J 2022; 36:e22456. [PMID: 35969153 DOI: 10.1096/fj.202101609rr] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2021] [Revised: 06/20/2022] [Accepted: 07/06/2022] [Indexed: 11/11/2022]
Abstract
The dorsal hippocampus plays a pivotal role in spatial memory. However, the role of subregion-specific molecular pathways in spatial cognition remains unclear. We observed that the transcriptional coregulator C-terminal binding protein 2 (CtBP2) presented CA3-specific enrichment in expression. RNAi interference of CtBP2 in the dorsal CA3 (dCA3) neurons, but not the ventral CA3 (vCA3), specifically impaired spatial reference memory and reduced the expression of GluR2, the calcium permeability determinant subunit of AMPA receptors. Application of an antagonist for GluR2-absent calcium permeable AMPA receptors rescued spatial memory deficits in dCA3 CtBP2 knockdown animals. Transcriptomic analysis suggest that CtBP2 may regulate GluR2 protein level through post-translational mechanisms, especially by the endocytosis pathway which regulates AMPA receptor sorting. Consistently, CtBP2 deficiency altered the mRNA expression of multiple endocytosis-regulatory genes, and CtBP2 knockdown in primary hippocampal neurons enhanced GluR2-containing AMPA receptor endocytosis. Together, our results provide evidence that the dCA3 regulates spatial reference memory by the CtBP2/GluR2 pathway through the modulation of calcium permeable AMPA receptors.
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Affiliation(s)
- Jia-Xuan Han
- Department of Neurology of the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China.,NHC and CAMS Key Laboratory of Medical Neurobiology, MOE Frontier Center of Brain Science and Brain-machine Integration, School of Brain Science and Brain Medicine, Zhejiang University School of Medicine, Hangzhou, China
| | - Chen-Xi Wen
- NHC and CAMS Key Laboratory of Medical Neurobiology, MOE Frontier Center of Brain Science and Brain-machine Integration, School of Brain Science and Brain Medicine, Zhejiang University School of Medicine, Hangzhou, China
| | - Rui Sun
- Department of Neurology of the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China.,NHC and CAMS Key Laboratory of Medical Neurobiology, MOE Frontier Center of Brain Science and Brain-machine Integration, School of Brain Science and Brain Medicine, Zhejiang University School of Medicine, Hangzhou, China
| | - Meng-Yu Tang
- Department of Neurology of the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China.,NHC and CAMS Key Laboratory of Medical Neurobiology, MOE Frontier Center of Brain Science and Brain-machine Integration, School of Brain Science and Brain Medicine, Zhejiang University School of Medicine, Hangzhou, China
| | - Xiao-Ming Li
- Department of Neurology of the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China.,NHC and CAMS Key Laboratory of Medical Neurobiology, MOE Frontier Center of Brain Science and Brain-machine Integration, School of Brain Science and Brain Medicine, Zhejiang University School of Medicine, Hangzhou, China
| | - Hong Lian
- Department of Neurology of the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
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5
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Morcom L, Gobius I, Marsh APL, Suárez R, Lim JWC, Bridges C, Ye Y, Fenlon LR, Zagar Y, Douglass AM, Donahoo ALS, Fothergill T, Shaikh S, Kozulin P, Edwards TJ, Cooper HM, Sherr EH, Chédotal A, Leventer RJ, Lockhart PJ, Richards LJ. DCC regulates astroglial development essential for telencephalic morphogenesis and corpus callosum formation. eLife 2021; 10:e61769. [PMID: 33871356 PMCID: PMC8116049 DOI: 10.7554/elife.61769] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2020] [Accepted: 04/18/2021] [Indexed: 02/04/2023] Open
Abstract
The forebrain hemispheres are predominantly separated during embryogenesis by the interhemispheric fissure (IHF). Radial astroglia remodel the IHF to form a continuous substrate between the hemispheres for midline crossing of the corpus callosum (CC) and hippocampal commissure (HC). Deleted in colorectal carcinoma (DCC) and netrin 1 (NTN1) are molecules that have an evolutionarily conserved function in commissural axon guidance. The CC and HC are absent in Dcc and Ntn1 knockout mice, while other commissures are only partially affected, suggesting an additional aetiology in forebrain commissure formation. Here, we find that these molecules play a critical role in regulating astroglial development and IHF remodelling during CC and HC formation. Human subjects with DCC mutations display disrupted IHF remodelling associated with CC and HC malformations. Thus, axon guidance molecules such as DCC and NTN1 first regulate the formation of a midline substrate for dorsal commissures prior to their role in regulating axonal growth and guidance across it.
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Affiliation(s)
- Laura Morcom
- The University of Queensland, Queensland Brain InstituteBrisbaneAustralia
| | - Ilan Gobius
- The University of Queensland, Queensland Brain InstituteBrisbaneAustralia
| | - Ashley PL Marsh
- Bruce Lefroy Centre for Genetic Health Research, Murdoch Children’s Research Institute, Royal Children’s HospitalParkvilleAustralia
- Department of Paediatrics, University of MelbourneParkvilleAustralia
| | - Rodrigo Suárez
- The University of Queensland, Queensland Brain InstituteBrisbaneAustralia
| | - Jonathan WC Lim
- The University of Queensland, Queensland Brain InstituteBrisbaneAustralia
| | - Caitlin Bridges
- The University of Queensland, Queensland Brain InstituteBrisbaneAustralia
| | - Yunan Ye
- The University of Queensland, Queensland Brain InstituteBrisbaneAustralia
| | - Laura R Fenlon
- The University of Queensland, Queensland Brain InstituteBrisbaneAustralia
| | - Yvrick Zagar
- Sorbonne Université, INSERM, CNRS, Institut de la VisionParisFrance
| | - Amelia M Douglass
- The University of Queensland, Queensland Brain InstituteBrisbaneAustralia
| | | | - Thomas Fothergill
- The University of Queensland, Queensland Brain InstituteBrisbaneAustralia
| | - Samreen Shaikh
- The University of Queensland, Queensland Brain InstituteBrisbaneAustralia
| | - Peter Kozulin
- The University of Queensland, Queensland Brain InstituteBrisbaneAustralia
| | - Timothy J Edwards
- The University of Queensland, Queensland Brain InstituteBrisbaneAustralia
- The University of Queensland, Faculty of MedicineBrisbaneAustralia
| | - Helen M Cooper
- The University of Queensland, Queensland Brain InstituteBrisbaneAustralia
| | - IRC5 Consortium
- Members and Affiliates of the International Research Consortium for the Corpus Callosum and Cerebral Connectivity (IRC5)Los AngelesUnited States
| | - Elliott H Sherr
- Departments of Neurology and Pediatrics, Institute of Human Genetics and Weill Institute of Neurosciences, University of California, San FranciscoSan FranciscoUnited States
| | - Alain Chédotal
- Sorbonne Université, INSERM, CNRS, Institut de la VisionParisFrance
| | - Richard J Leventer
- Department of Paediatrics, University of MelbourneParkvilleAustralia
- Neuroscience Research Group, Murdoch Children’s Research InstituteParkvilleAustralia
- Department of Neurology, University of Melbourne, Royal Children’s HospitalParkvilleAustralia
| | - Paul J Lockhart
- Bruce Lefroy Centre for Genetic Health Research, Murdoch Children’s Research Institute, Royal Children’s HospitalParkvilleAustralia
- Department of Paediatrics, University of MelbourneParkvilleAustralia
| | - Linda J Richards
- The University of Queensland, Queensland Brain InstituteBrisbaneAustralia
- The University of Queensland, School of Biomedical SciencesBrisbaneAustralia
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6
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Schiweck J, Murk K, Ledderose J, Münster-Wandowski A, Ornaghi M, Vida I, Eickholt BJ. Drebrin controls scar formation and astrocyte reactivity upon traumatic brain injury by regulating membrane trafficking. Nat Commun 2021; 12:1490. [PMID: 33674568 PMCID: PMC7935889 DOI: 10.1038/s41467-021-21662-x] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2020] [Accepted: 01/27/2021] [Indexed: 01/31/2023] Open
Abstract
The brain of mammals lacks a significant ability to regenerate neurons and is thus particularly vulnerable. To protect the brain from injury and disease, damage control by astrocytes through astrogliosis and scar formation is vital. Here, we show that brain injury in mice triggers an immediate upregulation of the actin-binding protein Drebrin (DBN) in astrocytes, which is essential for scar formation and maintenance of astrocyte reactivity. In turn, DBN loss leads to defective astrocyte scar formation and excessive neurodegeneration following brain injuries. At the cellular level, we show that DBN switches actin homeostasis from ARP2/3-dependent arrays to microtubule-compatible scaffolds, facilitating the formation of RAB8-positive membrane tubules. This injury-specific RAB8 membrane compartment serves as hub for the trafficking of surface proteins involved in astrogliosis and adhesion mediators, such as β1-integrin. Our work shows that DBN-mediated membrane trafficking in astrocytes is an important neuroprotective mechanism following traumatic brain injury in mice.
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Affiliation(s)
- Juliane Schiweck
- grid.6363.00000 0001 2218 4662Institute of Biochemistry, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Kai Murk
- grid.6363.00000 0001 2218 4662Institute of Biochemistry, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Julia Ledderose
- grid.6363.00000 0001 2218 4662Institute of Biochemistry, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | | | - Marta Ornaghi
- grid.6363.00000 0001 2218 4662Institute of Biochemistry, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Imre Vida
- grid.6363.00000 0001 2218 4662Institute of Anatomy, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Britta J. Eickholt
- grid.6363.00000 0001 2218 4662Institute of Biochemistry, Charité - Universitätsmedizin Berlin, Berlin, Germany ,grid.6363.00000 0001 2218 4662NeuroCure - Cluster of Excellence, Charité - Universitätsmedizin Berlin, Berlin, Germany
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7
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Vitovcova B, Skarkova V, Rudolf K, Rudolf E. Biology of Glioblastoma Multiforme-Exploration of Mitotic Catastrophe as a Potential Treatment Modality. Int J Mol Sci 2020; 21:ijms21155324. [PMID: 32727112 PMCID: PMC7432846 DOI: 10.3390/ijms21155324] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2020] [Revised: 07/22/2020] [Accepted: 07/25/2020] [Indexed: 12/23/2022] Open
Abstract
Glioblastoma multiforme (GBM) represents approximately 60% of all brain tumors in adults. This malignancy shows a high biological and genetic heterogeneity associated with exceptional aggressiveness, leading to a poor survival of patients. This review provides a summary of the basic biology of GBM cells with emphasis on cell cycle and cytoskeletal apparatus of these cells, in particular microtubules. Their involvement in the important oncosuppressive process called mitotic catastrophe will next be discussed along with select examples of microtubule-targeting agents, which are currently explored in this respect such as benzimidazole carbamate compounds. Select microtubule-targeting agents, in particular benzimidazole carbamates, induce G2/M cell cycle arrest and mitotic catastrophe in tumor cells including GBM, resulting in phenotypically variable cell fates such as mitotic death or mitotic slippage with subsequent cell demise or permanent arrest leading to senescence. Their effect is coupled with low toxicity in normal cells and not developed chemoresistance. Given the lack of efficient cytostatics or modern molecular target-specific compounds in the treatment of GBM, drugs inducing mitotic catastrophe might offer a new, efficient alternative to the existing clinical management of this at present incurable malignancy.
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Abstract
Astrocytes are the most abundant cell type in the central nervous system and have diverse functions in blood–brain barrier maintenance, neural circuitry formation and function, and metabolic regulation. To better understand the diverse roles of astrocytes, we will summarize what is known about astrocyte development and the challenges limiting our understanding of this process. We will also discuss new approaches and technologies advancing the field.
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Affiliation(s)
- Ekin Su Akdemir
- Center for Cell and Gene Therapy, Baylor College of Medicine, Houston, TX, 77030, USA.,Program in Developmental Biology, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Anna Yu-Szu Huang
- Center for Cell and Gene Therapy, Baylor College of Medicine, Houston, TX, 77030, USA.,Program in Developmental Biology, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Benjamin Deneen
- Center for Cell and Gene Therapy, Baylor College of Medicine, Houston, TX, 77030, USA.,Program in Developmental Biology, Baylor College of Medicine, Houston, TX, 77030, USA.,Department of Neuroscience, Baylor College of Medicine, Houston, TX, 77030, USA.,Department of Neurosurgery, Baylor College of Medicine, Houston, TX, 77030, USA
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9
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Ali AAH, Schwarz-Herzke B, Rollenhagen A, Anstötz M, Holub M, Lübke J, Rose CR, Schnittler HJ, von Gall C. Bmal1-deficiency affects glial synaptic coverage of the hippocampal mossy fiber synapse and the actin cytoskeleton in astrocytes. Glia 2019; 68:947-962. [PMID: 31743496 DOI: 10.1002/glia.23754] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2019] [Revised: 10/30/2019] [Accepted: 10/31/2019] [Indexed: 01/13/2023]
Abstract
Bmal1 is an essential component of the molecular clockwork, which drives circadian rhythms in cell function. In Bmal1-deficient (Bmal1-/-) mice, chronodisruption is associated with cognitive deficits and progressive brain pathology including astrocytosis indicated by increased expression of glial fibrillary acidic protein (GFAP). However, relatively little is known about the impact of Bmal1-deficiency on astrocyte morphology prior to astrocytosis. Therefore, in this study we analysed astrocyte morphology in young (6-8 weeks old) adult Bmal1-/- mice. At this age, overall GFAP immunoreactivity was not increased in Bmal1-deficient mice. At the ultrastructural level, we found a decrease in the volume fraction of the fine astrocytic processes that cover the hippocampal mossy fiber synapse, suggesting an impairment of perisynaptic processes and their contribution to neurotransmission. For further analyses of actin cytoskeleton, which is essential for distal process formation, we used cultured Bmal1-/- astrocytes. Bmal1-/- astrocytes showed an impaired formation of actin stress fibers. Moreover, Bmal1-/- astrocytes showed reduced levels of the actin-binding protein cortactin (CTTN). Cttn promoter region contains an E-Box like element and chromatin immunoprecipitation revealed that Cttn is a potential Bmal1 target gene. In addition, the level of GTP-bound (active) Rho-GTPase (Rho-GTP) was reduced in Bmal1-/- astrocytes. In summary, our data demonstrate that Bmal1-deficiency affects morphology of the fine astrocyte processes prior to strong upregulation of GFAP, presumably because of impaired Cttn expression and reduced Rho-GTP activation. These morphological changes might result in altered synaptic function and, thereby, relate to cognitive deficits in chronodisruption.
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Affiliation(s)
- Amira A H Ali
- Institute of Anatomy II, Medical Faculty, Heinrich Heine University, Düsseldorf, Germany
| | - Beryl Schwarz-Herzke
- Institute of Anatomy II, Medical Faculty, Heinrich Heine University, Düsseldorf, Germany
| | - Astrid Rollenhagen
- Institute of Neuroscience and Medicine INM-10, Research Centre Jülich GmbH, Jülich, Germany
| | - Max Anstötz
- Institute of Neuroscience and Medicine INM-10, Research Centre Jülich GmbH, Jülich, Germany
| | - Martin Holub
- Institute of Anatomy II, Medical Faculty, Heinrich Heine University, Düsseldorf, Germany
| | - Joachim Lübke
- Institute of Neuroscience and Medicine INM-10, Research Centre Jülich GmbH, Jülich, Germany.,Department of Psychiatry, Psychotherapy and Psychosomatics, Medical Faculty/RWTH University Hospital Aachen, Aachen, Germany.,Institute of Neuroscience and Medicine INM-10, JARA Translational Brain Medicine, Aachen, Germany
| | - Christine R Rose
- Institute of Neurobiology, Faculty of Mathematics and Natural Sciences, Heinrich Heine University, Düsseldorf, Germany
| | - Hans-Joachim Schnittler
- Institute of Anatomy and Vascular Biology, Medical Faculty, Westfälische Wilhelms University, Münster, Germany
| | - Charlotte von Gall
- Institute of Anatomy II, Medical Faculty, Heinrich Heine University, Düsseldorf, Germany
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10
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Chánez-Paredes S, Montoya-García A, Schnoor M. Cellular and pathophysiological consequences of Arp2/3 complex inhibition: role of inhibitory proteins and pharmacological compounds. Cell Mol Life Sci 2019; 76:3349-3361. [PMID: 31073744 PMCID: PMC11105272 DOI: 10.1007/s00018-019-03128-y] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2019] [Revised: 04/30/2019] [Accepted: 05/02/2019] [Indexed: 02/06/2023]
Abstract
The actin-related protein complex 2/3 (Arp2/3) generates branched actin networks important for many cellular processes such as motility, vesicular trafficking, cytokinesis, and intercellular junction formation and stabilization. Activation of Arp2/3 requires interaction with actin nucleation-promoting factors (NPFs). Regulation of Arp2/3 activity is achieved by endogenous inhibitory proteins through direct binding to Arp2/3 and competition with NPFs or by binding to Arp2/3-induced actin filaments and disassembly of branched actin networks. Arp2/3 inhibition has recently garnered more attention as it has been associated with attenuation of cancer progression, neurotoxic effects during drug abuse, and pathogen invasion of host cells. In this review, we summarize current knowledge on expression, inhibitory mechanisms and function of endogenous proteins able to inhibit Arp2/3 such as coronins, GMFs, PICK1, gadkin, and arpin. Moreover, we discuss cellular consequences of pharmacological Arp2/3 inhibition.
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Affiliation(s)
- Sandra Chánez-Paredes
- Department for Molecular Biomedicine, CINVESTAV-IPN, Av. IPN 2508, San Pedro Zacatenco, GAM, 07360, Mexico City, Mexico
| | - Armando Montoya-García
- Department for Molecular Biomedicine, CINVESTAV-IPN, Av. IPN 2508, San Pedro Zacatenco, GAM, 07360, Mexico City, Mexico
| | - Michael Schnoor
- Department for Molecular Biomedicine, CINVESTAV-IPN, Av. IPN 2508, San Pedro Zacatenco, GAM, 07360, Mexico City, Mexico.
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11
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Sakers K, Eroglu C. Control of neural development and function by glial neuroligins. Curr Opin Neurobiol 2019; 57:163-170. [PMID: 30991196 DOI: 10.1016/j.conb.2019.03.007] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2019] [Revised: 03/12/2019] [Accepted: 03/13/2019] [Indexed: 11/16/2022]
Abstract
Neuroligins are a family of cell adhesion molecules, which are best known for their functions as postsynaptic components of the trans-synaptic neurexin-neuroligin complexes. Neuroligins are highly conserved across evolution with important roles in the formation, maturation and function of synaptic structures. Mutations in the genes that encode for neuroligins have been linked to a number of neurodevelopmental disorders such as autism and schizophrenia, which stem from synaptic pathologies. Owing to their essential functions in regulating synaptic connectivity and their link to synaptic dysfunction in disease, previous studies on neuroligins have focused on neurons. Yet a recent work reveals that neuroligins are also expressed in the central nervous system by glial cells, such as astrocytes and oligodendrocytes, and perform important roles in controlling synaptic connectivity in a non-cell autonomous manner. In this review, we will highlight these recent findings demonstrating the important roles of glial neuroligins in regulating the development and connectivity of healthy and diseased brains.
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Affiliation(s)
- Kristina Sakers
- Department of Cell Biology, Duke University Medical Center, Durham, NC 27710, United States
| | - Cagla Eroglu
- Department of Cell Biology, Duke University Medical Center, Durham, NC 27710, United States; Department of Neurobiology, Duke University Medical Center, Durham, NC 27710, United States; Duke Institute for Brain Sciences (DIBS), Durham, NC 27710, United States; Regeneration Next Initiative, Duke University, Durham, NC 27710, United States.
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12
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ATM phosphorylation of the actin-binding protein drebrin controls oxidation stress-resistance in mammalian neurons and C. elegans. Nat Commun 2019; 10:486. [PMID: 30700723 PMCID: PMC6353951 DOI: 10.1038/s41467-019-08420-w] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2018] [Accepted: 12/27/2018] [Indexed: 12/13/2022] Open
Abstract
Drebrin (DBN) regulates cytoskeletal functions during neuronal development, and is thought to contribute to structural and functional synaptic changes associated with aging and Alzheimer’s disease. Here we show that DBN coordinates stress signalling with cytoskeletal dynamics, via a mechanism involving kinase ataxia-telangiectasia mutated (ATM). An excess of reactive oxygen species (ROS) stimulates ATM-dependent phosphorylation of DBN at serine-647, which enhances protein stability and accounts for improved stress resilience in dendritic spines. We generated a humanized DBN Caenorhabditis elegans model and show that a phospho-DBN mutant disrupts the protective ATM effect on lifespan under sustained oxidative stress. Our data indicate a master regulatory function of ATM-DBN in integrating cytosolic stress-induced signalling with the dynamics of actin remodelling to provide protection from synapse dysfunction and ROS-triggered reduced lifespan. They further suggest that DBN protein abundance governs actin filament stability to contribute to the consequences of oxidative stress in physiological and pathological conditions. Drebrin is an actin-binding protein known to play a role in neuronal dendritic spines but its precise regulation is unclear. Here, the authors report that DBN is activated by oxidative stress in an ATM-kinase dependent manner and increases resistance to oxidative stress in mice and in C. elegans.
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13
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Decreased expression of LATS1 correlates with astrogliosis after spinal cord injury. Biochem Biophys Res Commun 2018; 505:151-156. [PMID: 30241940 DOI: 10.1016/j.bbrc.2018.09.025] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Accepted: 09/06/2018] [Indexed: 02/06/2023]
Abstract
Large tumor suppressor kinase 1 (LATS1) is a serine/threonine kinase of the AGC kinase family in mammals and involved in various biological processes, it is a key regulator of cell cycle progression. However, the role of LATS1 in central nervous system trauma is still unknown. In present study, we performed an acute spinal cord injury (SCI) model in adult rats and investigated the dynamic changes of LATS1 expression in the spinal cord. We found that LATS1 protein levels were significantly decreased at day 1 after injury. Meanwhile, double immunofluorescence staining showed these changes were striking in astrocytes, which were largely proliferated after SCI. In vitro, LATS1 overexpression inhibited astrocyte proliferation. Conversely, LATS1 depletion by siRNA promoted cell proliferation in primary astrocyte. Moreover, LATS1 overexpression reduced cyclin D1 expression and increased the expression of p27kip1. In addition, LATS1 overexpression also promoted yes-associated protein 1 (YAP) phosphorylation. Our data suggested that LATS1 might play an important role in spinal cord injury and suppress astrogliosis through regulating the expression of cyclin D1, p27kip1 and p-YAP.
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Schiweck J, Eickholt BJ, Murk K. Important Shapeshifter: Mechanisms Allowing Astrocytes to Respond to the Changing Nervous System During Development, Injury and Disease. Front Cell Neurosci 2018; 12:261. [PMID: 30186118 PMCID: PMC6111612 DOI: 10.3389/fncel.2018.00261] [Citation(s) in RCA: 117] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2018] [Accepted: 07/31/2018] [Indexed: 12/30/2022] Open
Abstract
Astrocytes are the most prevalent glial cells in the brain. Historically considered as “merely supporting” neurons, recent research has shown that astrocytes actively participate in a large variety of central nervous system (CNS) functions including synaptogenesis, neuronal transmission and synaptic plasticity. During disease and injury, astrocytes efficiently protect neurons by various means, notably by sealing them off from neurotoxic factors and repairing the blood-brain barrier. Their ramified morphology allows them to perform diverse tasks by interacting with synapses, blood vessels and other glial cells. In this review article, we provide an overview of how astrocytes acquire their complex morphology during development. We then move from the developing to the mature brain, and review current research on perisynaptic astrocytic processes, with a particular focus on how astrocytes engage synapses and modulate their formation and activity. Comprehensive changes have been reported in astrocyte cell shape in many CNS pathologies. Factors influencing these morphological changes are summarized in the context of brain pathologies, such as traumatic injury and degenerative conditions. We provide insight into the molecular, cellular and cytoskeletal machinery behind these shape changes which drive the dynamic remodeling in astrocyte morphology during injury and the development of pathologies.
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Affiliation(s)
- Juliane Schiweck
- Institute for Biochemistry, Charité Universitätsmedizin Berlin, Berlin, Germany
| | - Britta J Eickholt
- Institute for Biochemistry, Charité Universitätsmedizin Berlin, Berlin, Germany
| | - Kai Murk
- Institute for Biochemistry, Charité Universitätsmedizin Berlin, Berlin, Germany
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15
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Barnes J, Salas F, Mokhtari R, Dolstra H, Pedrosa E, Lachman HM. Modeling the neuropsychiatric manifestations of Lowe syndrome using induced pluripotent stem cells: defective F-actin polymerization and WAVE-1 expression in neuronal cells. Mol Autism 2018; 9:44. [PMID: 30147856 PMCID: PMC6094927 DOI: 10.1186/s13229-018-0227-3] [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: 12/22/2017] [Accepted: 07/29/2018] [Indexed: 12/12/2022] Open
Abstract
Background Lowe syndrome (LS) is a rare genetic disorder caused by loss of function mutations in the X-linked gene, OCRL, which codes for inositol polyphosphate 5-phosphatase. LS is characterized by the triad of congenital cataracts, neurodevelopmental impairment (primarily intellectual and developmental disabilities [IDD]), and renal proximal tubular dysfunction. Studies carried out over the years have shown that hypomorphic mutations in OCRL adversely affect endosome recycling and actin polymerization in kidney cells and patient-derived fibroblasts. The renal problem has been traced to an impaired recycling of megalin, a multi-ligand receptor that plays a key role in the reuptake of lipoproteins, amino acids, vitamin-binding proteins, and hormones. However, the neurodevelopmental aspects of the disorder have been difficult to study because the mouse knockout (KO) model does not display LS-related phenotypes. Fortunately, the discovery of induced pluripotent stem (iPS) cells has provided an opportunity to grow patient-specific neurons, which can be used to model neurodevelopmental disorders in vitro, as demonstrated in the many studies that have been published in the past few years in autism spectrum disorders (ASD), schizophrenia (SZ), bipolar disorder (BD), and IDD. Methods We now report the first findings in neurons and neural progenitor cells (NPCs) generated from iPS cells derived from patients with LS and their typically developing male siblings, as well as an isogenic line in which the OCRL gene has been incapacitated by a null mutation generated using CRISPR-Cas9 gene editing. Results We show that neuronal cells derived from patient-specific iPS cells containing hypomorphic variants are deficient in their capacity to produce F-filamentous actin (F-actin) fibers. Abnormalities were also found in the expression of WAVE-1, a component of the WAVE regulatory complex (WRC) that regulates actin polymerization. Curiously, neuronal cells carrying the engineered OCRL null mutation, in which OCRL protein is not expressed, did not show similar defects in F-actin and WAVE-1 expression. This is similar to the apparent lack of a phenotype in the mouse Ocrl KO model, and suggests that in the complete absence of OCRL protein, as opposed to producing a dysfunctional protein, as seen with the hypomorphic variants, there is partial compensation for the F-actin/WAVE-1 regulating function of OCRL. Conclusions Alterations in F-actin polymerization and WRC have been found in a number of genetic subgroups of IDD and ASD. Thus, LS, a very rare genetic condition, is linked to a more expansive family of genes responsible for neurodevelopmental disorders that have shared pathogenic features. Electronic supplementary material The online version of this article (10.1186/s13229-018-0227-3) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Jesse Barnes
- 1Department of Genetics, Albert Einstein College of Medicine, Bronx, New York, USA
| | - Franklin Salas
- 2Department of Psychiatry and Behavioral Sciences, Albert Einstein College of Medicine, Bronx, New York, USA
| | - Ryan Mokhtari
- 3Department of Neuroscience and Physiology, SUNY Upstate Medical University, Syracuse, New York, USA
| | - Hedwig Dolstra
- 4Swammerdam Institute of Life Sciences, University of Amsterdam, Amsterdam, Netherlands
| | - Erika Pedrosa
- 2Department of Psychiatry and Behavioral Sciences, Albert Einstein College of Medicine, Bronx, New York, USA
| | - Herbert M Lachman
- 1Department of Genetics, Albert Einstein College of Medicine, Bronx, New York, USA.,2Department of Psychiatry and Behavioral Sciences, Albert Einstein College of Medicine, Bronx, New York, USA.,5Department of Neuroscience, Albert Einstein College of Medicine, Bronx, New York, USA.,6Department of Medicine, Albert Einstein College of Medicine, Bronx, New York, USA
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16
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Yamagishi Y, Oya K, Matsuura A, Abe H. Use of CK-548 and CK-869 as Arp2/3 complex inhibitors directly suppresses microtubule assembly both in vitro and in vivo. Biochem Biophys Res Commun 2018; 496:834-839. [PMID: 29395083 DOI: 10.1016/j.bbrc.2018.01.143] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2018] [Accepted: 01/23/2018] [Indexed: 11/28/2022]
Abstract
Two types of Arp2/3 complex inhibitors, CK-666/636 and CK-548/869, are commonly used to study Arp2/3 complex-dependent actin assembly both in vitro and in vivo. However, we found that CK-548 and CK-869 directly suppress microtubule (MT) assembly independent of the actin cytoskeleton. Treatment of cultured mammalian cells with 50 μM CK-869 dramatically decreased MT networks and, instead, accumulated tubulin at the cell periphery, as did nocodazole that inhibits MT assembly. An in vitro MT-sedimentation assay revealed that CK-548 and CK-869 significantly suppressed MT polymerization. In budding yeast, although CK-548 and CK-869 are reported to lack binding abilities in the yeast Arp3, CK-548 treatment decreased cytoplasmic MT at several tens of micromolar concentrations. In addition, we found that the effects of CK-548 and CK-869 on MT assembly varied according to species. We propose that CK-548 and CK-869 are not suitable for studying the cytoskeleton in living cells.
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Affiliation(s)
- Yuka Yamagishi
- Department of Nanobiology, Graduate School of Advanced Integration Science, Chiba University, Chiba 263-8522, Japan.
| | - Kazumasa Oya
- Department of Biology, Graduate School of Science, Chiba University, Chiba 263-8522, Japan
| | - Akira Matsuura
- Department of Nanobiology, Graduate School of Advanced Integration Science, Chiba University, Chiba 263-8522, Japan; Department of Biology, Graduate School of Science, Chiba University, Chiba 263-8522, Japan
| | - Hiroshi Abe
- Department of Nanobiology, Graduate School of Advanced Integration Science, Chiba University, Chiba 263-8522, Japan; Department of Biology, Graduate School of Science, Chiba University, Chiba 263-8522, Japan.
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17
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Molinie N, Gautreau A. The Arp2/3 Regulatory System and Its Deregulation in Cancer. Physiol Rev 2017; 98:215-238. [PMID: 29212790 DOI: 10.1152/physrev.00006.2017] [Citation(s) in RCA: 119] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2017] [Revised: 05/10/2017] [Accepted: 05/11/2017] [Indexed: 02/07/2023] Open
Abstract
The Arp2/3 complex is an evolutionary conserved molecular machine that generates branched actin networks. When activated, the Arp2/3 complex contributes the actin branched junction and thus cross-links the polymerizing actin filaments in a network that exerts a pushing force. The different activators initiate branched actin networks at the cytosolic surface of different cellular membranes to promote their protrusion, movement, or scission in cell migration and membrane traffic. Here we review the structure, function, and regulation of all the direct regulators of the Arp2/3 complex that induce or inhibit the initiation of a branched actin network and that controls the stability of its branched junctions. Our goal is to present recent findings concerning novel inhibitory proteins or the regulation of the actin branched junction and place these in the context of what was previously known to provide a global overview of how the Arp2/3 complex is regulated in human cells. We focus on the human set of Arp2/3 regulators to compare normal Arp2/3 regulation in untransformed cells to the deregulation of the Arp2/3 system observed in patients affected by various cancers. In many cases, these deregulations promote cancer progression and have a direct impact on patient survival.
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Affiliation(s)
- Nicolas Molinie
- Ecole Polytechnique, Université Paris-Saclay, CNRS UMR 7654, Palaiseau, France; and Moscow Institute of Physics and Technology, Life Sciences Center, Dolgoprudny, Russia
| | - Alexis Gautreau
- Ecole Polytechnique, Université Paris-Saclay, CNRS UMR 7654, Palaiseau, France; and Moscow Institute of Physics and Technology, Life Sciences Center, Dolgoprudny, Russia
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18
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MicroRNA-211/BDNF axis regulates LPS-induced proliferation of normal human astrocyte through PI3K/AKT pathway. Biosci Rep 2017; 37:BSR20170755. [PMID: 28790168 PMCID: PMC5563540 DOI: 10.1042/bsr20170755] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2017] [Revised: 07/20/2017] [Accepted: 08/08/2017] [Indexed: 01/09/2023] Open
Abstract
Spinal cord injury (SCI) makes a major contribution to disability and deaths worldwide. Reactive astrogliosis, a typical feature after SCI, which undergoes varying molecular and morphological changes, is ubiquitous but poorly understood. Reactive astrogliosis contributes to glial scar formation that impedes axonal regeneration. Brain-derived neurotrophic factor (BDNF), a well-established neurotrophic factor, exerts neuroprotective and growth-promoting effects on a variety of neuronal populations after injury. In the present study, by using LPS-induced in vitro injury model of astroglial cultures, we observed a high expression of interleukin (IL)-6, IL-1β, and BDNF in LPS-stimulated normal human astrocytes (NHAs). BDNF significantly promoted NHA proliferation. Further, online tools were employed to screen the candidate miRNAs which might directly target BDNF to inhibit its expression. Amongst the candidate miRNAs, miR-211 expression was down-regulated by LPS stimulation in a dose-dependent manner. Through direct targetting, miR-211 inhibited BDNF expression. Ectopic miR-211 expression significantly suppressed NHA proliferation, as well as LPS-induced activation of PI3K/Akt pathway. In contrast, inhibition of miR-211 expression significantly promoted NHA proliferation and LPS-induced activation of PI3K/Akt pathway. Taken together, miR-211/BDNF axis regulates LPS-induced NHA proliferation through PI3K/AKT pathway; miR-211/BDNF might serve as a promising target in the strategy against reactive astrocyte proliferation after SCI.
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19
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Control of astrocyte morphology by Rho GTPases. Brain Res Bull 2017; 136:44-53. [PMID: 28502648 DOI: 10.1016/j.brainresbull.2017.05.003] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2016] [Revised: 05/05/2017] [Accepted: 05/10/2017] [Indexed: 12/15/2022]
Abstract
Astrocytes modulate and support neuronal and synapse function via numerous mechanisms that often rely on diffusion of signalling molecules, ions or metabolites through extracellular space. As a consequence, the spatial arrangement and the distance between astrocyte processes and neuronal structures are of functional importance. Likewise, changes of astrocyte structure will affect the ability of astrocytes to interact with neurons. In contrast to neurons, where rapid morphology changes are critically involved in many aspects of physiological brain function, a role of astrocyte restructuring in brain physiology is only beginning to emerge. In neurons, small GTPases of the Rho family are powerful initiators and modulators of structural changes. Less is known about the functional significance of these signalling molecules in astrocytes. Here, we review recent experimental evidence for the role of RhoA, Cdc42 and Rac1 in controlling dynamic astrocyte morphology as well as experimental tools and analytical approaches for studying astrocyte morphology changes.
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20
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Chen J, Cui Z, Yang S, Wu C, Li W, Bao G, Xu G, Sun Y, Wang L, Zhang J. The upregulation of annexin A2 after spinal cord injury in rats may have implication for astrocyte proliferation. Neuropeptides 2017; 61:67-76. [PMID: 27836325 DOI: 10.1016/j.npep.2016.10.007] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/02/2016] [Revised: 10/18/2016] [Accepted: 10/24/2016] [Indexed: 01/03/2023]
Abstract
Annexin A2 (ANXA2), is a member of the annexin family of proteins that exhibit Ca2+-dependent binding to phospholipids. One attractive biological function of ANXA2 is participating in DNA synthesis and cell proliferation. Previous studies have shown that ANXA2 play a role in the development of the central nervous system. However, the biological function of ANXA2 after spinal cord injury (SCI) is still with limited acquaintance. In the present study, we performed a SCI model in adult rats and investigated the dynamic changes of ANXA2 expression in the spinal cord. Western blot analysis indicated a striking expression upregulation of ANXA2 after SCI. Immunohistochemistry further confirmed that ANXA2 immunoactivity was expressed at low levels in normal condition and increased at 5day after SCI. Double immunofluorescence staining prompted that ANXA2 immunoreactivity was found in astrocytes and neurons. Interestingly, ANXA2 expression was increased predominantly in astrocytes. We also examined the expression profiles of proliferating cell nuclear antigen (PCNA), Cyclin D1 and active caspase-3 in the injured spinal cords by western blot. Co-expression of ANXA2/PCNA, ANXA2/Cyclin D1 was detected in glial fibrillary acidic protein. Importantly, double immunofluorescence staining revealed that cell proliferation evaluated by PCNA appeared in many ANXA2-expressing cells and rare caspase-3 was observed in ANXA2-expressing cells after SCI. In addition, ANXA2 knockdown in astrocytes resulted in the increase of PCNA expression after LPS stimulation, showing that ANXA2 inhibited astrocyte proliferation after inflammation. Our data suggested that ANXA2 might play important roles in CNS pathophysiology after SCI.
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Affiliation(s)
- Jiajia Chen
- Department of Spine Surgery, The Second Affiliated Hospital of Nantong University, Nantong University, 226001 Nantong, Jiangsu, People's Republic of China
| | - Zhiming Cui
- Department of Spine Surgery, The Second Affiliated Hospital of Nantong University, Nantong University, 226001 Nantong, Jiangsu, People's Republic of China.
| | - Saishuai Yang
- Department of Spine Surgery, The Second Affiliated Hospital of Nantong University, Nantong University, 226001 Nantong, Jiangsu, People's Republic of China
| | - Chunshuai Wu
- Department of Spine Surgery, The Second Affiliated Hospital of Nantong University, Nantong University, 226001 Nantong, Jiangsu, People's Republic of China
| | - Weidong Li
- Department of Spine Surgery, The Second Affiliated Hospital of Nantong University, Nantong University, 226001 Nantong, Jiangsu, People's Republic of China
| | - Guofeng Bao
- Department of Spine Surgery, The Second Affiliated Hospital of Nantong University, Nantong University, 226001 Nantong, Jiangsu, People's Republic of China
| | - Guanhua Xu
- Department of Spine Surgery, The Second Affiliated Hospital of Nantong University, Nantong University, 226001 Nantong, Jiangsu, People's Republic of China
| | - Yuyu Sun
- Department of Spine Surgery, The Second Affiliated Hospital of Nantong University, Nantong University, 226001 Nantong, Jiangsu, People's Republic of China
| | - Lingling Wang
- Department of Spine Surgery, The Second Affiliated Hospital of Nantong University, Nantong University, 226001 Nantong, Jiangsu, People's Republic of China
| | - Jinlong Zhang
- Department of Spine Surgery, The Second Affiliated Hospital of Nantong University, Nantong University, 226001 Nantong, Jiangsu, People's Republic of China
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21
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Tehrani S, Davis L, Cepurna WO, Choe TE, Lozano DC, Monfared A, Cooper L, Cheng J, Johnson EC, Morrison JC. Astrocyte Structural and Molecular Response to Elevated Intraocular Pressure Occurs Rapidly and Precedes Axonal Tubulin Rearrangement within the Optic Nerve Head in a Rat Model. PLoS One 2016; 11:e0167364. [PMID: 27893827 PMCID: PMC5125687 DOI: 10.1371/journal.pone.0167364] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2016] [Accepted: 11/12/2016] [Indexed: 02/01/2023] Open
Abstract
Glaucomatous axon injury occurs at the level of the optic nerve head (ONH) in response to uncontrolled intraocular pressure (IOP). The temporal response of ONH astrocytes (glial cells responsible for axonal support) to elevated IOP remains unknown. Here, we evaluate the response of actin-based astrocyte extensions and integrin-based signaling within the ONH to 8 hours of IOP elevation in a rat model. IOP elevation of 60 mm Hg was achieved under isoflurane anesthesia using anterior chamber cannulation connected to a saline reservoir. ONH astrocytic extension orientation was significantly and regionally rearranged immediately after IOP elevation (inferior ONH, 43.2° ± 13.3° with respect to the anterior-posterior axis versus 84.1° ± 1.3° in controls, p<0.05), and re-orientated back to baseline orientation 1 day post IOP normalization. ONH axonal microtubule filament label intensity was significantly reduced 1 and 3 days post IOP normalization, and returned to control levels on day 5. Phosphorylated focal adhesion kinase (FAK) levels steadily decreased after IOP normalization, while levels of phosphorylated paxillin (a downstream target of FAK involved in focal adhesion dynamics) were significantly elevated 5 days post IOP normalization. The levels of phosphorylated cortactin (a downstream target of Src kinase involved in actin polymerization) were significantly elevated 1 and 3 days post IOP normalization and returned to control levels by day 5. No significant axon degeneration was noted by morphologic assessment up to 5 days post IOP normalization. Actin-based astrocyte structure and signaling within the ONH are significantly altered within hours after IOP elevation and prior to axonal cytoskeletal rearrangement, producing some responses that recover rapidly and others that persist for days despite IOP normalization.
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Affiliation(s)
- Shandiz Tehrani
- Casey Eye Institute, Department of Ophthalmology, Oregon Health & Science University, Portland, Oregon, United States of America
- * E-mail:
| | - Lauren Davis
- Casey Eye Institute, Department of Ophthalmology, Oregon Health & Science University, Portland, Oregon, United States of America
| | - William O. Cepurna
- Casey Eye Institute, Department of Ophthalmology, Oregon Health & Science University, Portland, Oregon, United States of America
| | - Tiffany E. Choe
- Casey Eye Institute, Department of Ophthalmology, Oregon Health & Science University, Portland, Oregon, United States of America
| | - Diana C. Lozano
- Casey Eye Institute, Department of Ophthalmology, Oregon Health & Science University, Portland, Oregon, United States of America
| | - Ashley Monfared
- Casey Eye Institute, Department of Ophthalmology, Oregon Health & Science University, Portland, Oregon, United States of America
| | - Lauren Cooper
- Casey Eye Institute, Department of Ophthalmology, Oregon Health & Science University, Portland, Oregon, United States of America
| | - Joshua Cheng
- Casey Eye Institute, Department of Ophthalmology, Oregon Health & Science University, Portland, Oregon, United States of America
| | - Elaine C. Johnson
- Casey Eye Institute, Department of Ophthalmology, Oregon Health & Science University, Portland, Oregon, United States of America
| | - John C. Morrison
- Casey Eye Institute, Department of Ophthalmology, Oregon Health & Science University, Portland, Oregon, United States of America
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22
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Multiple faces of protein interacting with C kinase 1 (PICK1): Structure, function, and diseases. Neurochem Int 2016; 98:115-21. [DOI: 10.1016/j.neuint.2016.03.001] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2015] [Revised: 03/02/2016] [Accepted: 03/02/2016] [Indexed: 11/19/2022]
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Astrocytic GAP43 Induced by the TLR4/NF-κB/STAT3 Axis Attenuates Astrogliosis-Mediated Microglial Activation and Neurotoxicity. J Neurosci 2016; 36:2027-43. [PMID: 26865625 DOI: 10.1523/jneurosci.3457-15.2016] [Citation(s) in RCA: 85] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
UNLABELLED Growth-associated protein 43 (GAP43), a protein kinase C (PKC)-activated phosphoprotein, is often implicated in axonal plasticity and regeneration. In this study, we found that GAP43 can be induced by the endotoxin lipopolysaccharide (LPS) in rat brain astrocytes both in vivo and in vitro. The LPS-induced astrocytic GAP43 expression was mediated by Toll-like receptor 4 and nuclear factor-κB (NF-κB)- and interleukin-6/signal transducer and activator of transcription 3 (STAT3)-dependent transcriptional activation. The overexpression of the PKC phosphorylation-mimicking GAP43(S41D) (constitutive active GAP43) in astrocytes mimicked LPS-induced process arborization and elongation, while application of a NF-κB inhibitory peptide TAT-NBD or GAP43(S41A) (dominant-negative GAP43) or knockdown of GAP43 all inhibited astrogliosis responses. Moreover, GAP43 knockdown aggravated astrogliosis-induced microglial activation and expression of proinflammatory cytokines. We also show that astrogliosis-conditioned medium from GAP43 knock-down astrocytes inhibited GAP43 phosphorylation and axonal growth, and increased neuronal damage in cultured rat cortical neurons. These proneurotoxic effects of astrocytic GAP43 knockdown were accompanied by attenuated glutamate uptake and expression of the glutamate transporter excitatory amino acid transporter 2 (EAAT2) in LPS-treated astrocytes. The regulation of EAAT2 expression involves actin polymerization-dependent activation of the transcriptional coactivator megakaryoblastic leukemia 1 (MKL1), which targets the serum response elements in the promoter of rat Slc1a2 gene encoding EAAT2. In sum, the present study suggests that astrocytic GAP43 mediates glial plasticity during astrogliosis, and provides beneficial effects for neuronal plasticity and survival and attenuation of microglial activation. SIGNIFICANCE STATEMENT Astrogliosis is a complex state in which injury-stimulated astrocytes exert both protective and harmful effects on neuronal survival and plasticity. In this study, we demonstrated for the first time that growth-associated protein 43 (GAP43), a well known growth cone protein that promotes axonal regeneration, can be induced in rat brain astrocytes by the proinflammatory endotoxin lipopolysaccharide via both nuclear factor-κB and signal transducer and activator of transcription 3-mediated transcriptional activation. Importantly, LPS-induced GAP43 mediates plastic changes of astrocytes while attenuating astrogliosis-induced microglial activation and neurotoxicity. Hence, astrocytic GAP43 upregulation may serve to indicate beneficial astrogliosis after CNS injury.
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Abeysinghe HCS, Phillips EL, Chin-Cheng H, Beart PM, Roulston CL. Modulating Astrocyte Transition after Stroke to Promote Brain Rescue and Functional Recovery: Emerging Targets Include Rho Kinase. Int J Mol Sci 2016; 17:288. [PMID: 26927079 PMCID: PMC4813152 DOI: 10.3390/ijms17030288] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2015] [Revised: 01/26/2016] [Accepted: 02/05/2016] [Indexed: 01/13/2023] Open
Abstract
Stroke is a common and serious condition, with few therapies. Whilst previous focus has been directed towards biochemical events within neurons, none have successfully prevented the progression of injury that occurs in the acute phase. New targeted treatments that promote recovery after stroke might be a better strategy and are desperately needed for the majority of stroke survivors. Cells comprising the neurovascular unit, including blood vessels and astrocytes, present an alternative target for supporting brain rescue and recovery in the late phase of stroke, since alteration in the unit also occurs in regions outside of the lesion. One of the major changes in the unit involves extensive morphological transition of astrocytes resulting in altered energy metabolism, decreased glutamate reuptake and recycling, and retraction of astrocyte end feed from both blood vessels and neurons. Whilst globally inhibiting transitional change in astrocytes after stroke is reported to result in further damage and functional loss, we discuss the available evidence to suggest that the transitional activation of astrocytes after stroke can be modulated for improved outcomes. In particular, we review the role of Rho-kinase (ROCK) in reactive gliosis and show that inhibiting ROCK after stroke results in reduced scar formation and improved functional recovery.
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Affiliation(s)
- Hima Charika S Abeysinghe
- Neurotrauma Research, Department of Medicine, St Vincent's Campus, University of Melbourne, Parkville, VIC 3065, Australia.
- Department of Surgery, St Vincent's Campus, University of Melbourne, Parkville, VIC 3065, Australia.
| | - Ellie L Phillips
- Department of Biochemistry and Molecular Biology, Bio21 Insitute, University of Melbourne, Parkville, VIC 3010, Australia.
| | - Heung Chin-Cheng
- Department of Biochemistry and Molecular Biology, Bio21 Insitute, University of Melbourne, Parkville, VIC 3010, Australia.
| | - Philip M Beart
- The Florey Institute of Neuroscience and Mental Health, Melbourne Brain Centre, Parkville, VIC 3010, Australia.
| | - Carli L Roulston
- Neurotrauma Research, Department of Medicine, St Vincent's Campus, University of Melbourne, Parkville, VIC 3065, Australia.
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25
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Newell-Litwa KA, Horwitz R, Lamers ML. Non-muscle myosin II in disease: mechanisms and therapeutic opportunities. Dis Model Mech 2015; 8:1495-515. [PMID: 26542704 PMCID: PMC4728321 DOI: 10.1242/dmm.022103] [Citation(s) in RCA: 94] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The actin motor protein non-muscle myosin II (NMII) acts as a master regulator of cell morphology, with a role in several essential cellular processes, including cell migration and post-synaptic dendritic spine plasticity in neurons. NMII also generates forces that alter biochemical signaling, by driving changes in interactions between actin-associated proteins that can ultimately regulate gene transcription. In addition to its roles in normal cellular physiology, NMII has recently emerged as a critical regulator of diverse, genetically complex diseases, including neuronal disorders, cancers and vascular disease. In the context of these disorders, NMII regulatory pathways can be directly mutated or indirectly altered by disease-causing mutations. NMII regulatory pathway genes are also increasingly found in disease-associated copy-number variants, particularly in neuronal disorders such as autism and schizophrenia. Furthermore, manipulation of NMII-mediated contractility regulates stem cell pluripotency and differentiation, thus highlighting the key role of NMII-based pharmaceuticals in the clinical success of stem cell therapies. In this Review, we discuss the emerging role of NMII activity and its regulation by kinases and microRNAs in the pathogenesis and prognosis of a diverse range of diseases, including neuronal disorders, cancer and vascular disease. We also address promising clinical applications and limitations of NMII-based inhibitors in the treatment of these diseases and the development of stem-cell-based therapies.
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Affiliation(s)
- Karen A Newell-Litwa
- Department of Cell Biology, University of Virginia, Charlottesville, VA 22908, USA
| | - Rick Horwitz
- Department of Cell Biology, University of Virginia, Charlottesville, VA 22908, USA
| | - Marcelo L Lamers
- Department of Morphological Sciences, Institute of Basic Health Science, Federal University of Rio Grande do Sul, Porto Alegre, Rio Grande do Sul 90610-010, Brazil
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26
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Smith I, Haag M, Ugbode C, Tams D, Rattray M, Przyborski S, Bithell A, Whalley BJ. Neuronal-glial populations form functional networks in a biocompatible 3D scaffold. Neurosci Lett 2015; 609:198-202. [DOI: 10.1016/j.neulet.2015.10.044] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2015] [Revised: 10/06/2015] [Accepted: 10/14/2015] [Indexed: 11/30/2022]
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Cockbill LMR, Murk K, Love S, Hanley JG. Protein interacting with C kinase 1 suppresses invasion and anchorage-independent growth of astrocytic tumor cells. Mol Biol Cell 2015; 26:4552-61. [PMID: 26466675 PMCID: PMC4678014 DOI: 10.1091/mbc.e15-05-0270] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2015] [Accepted: 10/07/2015] [Indexed: 12/11/2022] Open
Abstract
Astrocytic tumors are the most common form of primary brain tumor. Astrocytic tumor cells infiltrate the surrounding CNS tissue, allowing them to evade removal upon surgical resection of the primary tumor. Dynamic changes to the actin cytoskeleton are crucial to cancer cell invasion, but the specific mechanisms that underlie the particularly invasive phenotype of astrocytic tumor cells are unclear. Protein interacting with C kinase 1 (PICK1) is a PDZ and BAR domain-containing protein that inhibits actin-related protein 2/3 (Arp2/3)-dependent actin polymerization and is involved in regulating the trafficking of a number of cell-surface receptors. Here we report that, in contrast to other cancers, PICK1 expression is down-regulated in grade IV astrocytic tumor cell lines and also in clinical cases of the disease in which grade IV tumors have progressed from lower-grade tumors. Exogenous expression of PICK1 in the grade IV astrocytic cell line U251 reduces their capacity for anchorage-independent growth, two-dimensional migration, and invasion through a three-dimensional matrix, strongly suggesting that low PICK1 expression plays an important role in astrocytic tumorigenesis. We propose that PICK1 negatively regulates neoplastic infiltration of astrocytic tumors and that manipulation of PICK1 is an attractive possibility for therapeutic intervention.
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Affiliation(s)
- Louisa M R Cockbill
- School of Biochemistry, University of Bristol, Bristol BS8 1TD, United Kingdom
| | - Kai Murk
- School of Biochemistry, University of Bristol, Bristol BS8 1TD, United Kingdom
| | - Seth Love
- School of Clinical Sciences, University of Bristol, Bristol BS10 5NB, United Kingdom
| | - Jonathan G Hanley
- School of Biochemistry, University of Bristol, Bristol BS8 1TD, United Kingdom
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28
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SMIFH2 has effects on Formins and p53 that perturb the cell cytoskeleton. Sci Rep 2015; 5:9802. [PMID: 25925024 PMCID: PMC5386218 DOI: 10.1038/srep09802] [Citation(s) in RCA: 56] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2014] [Accepted: 03/19/2015] [Indexed: 01/08/2023] Open
Abstract
Formin proteins are key regulators of the cytoskeleton involved in developmental and homeostatic programs, and human disease. For these reasons, small molecules interfering with Formins' activity have gained increasing attention. Among them, small molecule inhibitor of Formin Homology 2 domains (SMIFH2) is often used as a pharmacological Formin blocker. Although SMIFH2 inhibits actin polymerization by Formins and affects the actin cytoskeleton, its cellular mechanism of action and target specificity remain unclear. Here we show that SMIFH2 induces remodelling of actin filaments, microtubules and the Golgi complex as a result of its effects on Formins and p53. We found that SMIFH2 triggers alternated depolymerization-repolymerization cycles of actin and tubulin, increases cell migration, causes scattering of the Golgi complex, and also cytotoxicity at high dose. Moreover, SMIFH2 reduces expression and activity of p53 through a post-transcriptional, proteasome-independent mechanism that influences remodelling of the cytoskeleton. As the action of SMIFH2 may go beyond Formin inhibition, only short-term and low-dose SMIFH2 treatments minimize confounding effects induced by loss of p53 and cytotoxicity.
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29
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Xie AX, Petravicz J, McCarthy KD. Molecular approaches for manipulating astrocytic signaling in vivo. Front Cell Neurosci 2015; 9:144. [PMID: 25941472 PMCID: PMC4403552 DOI: 10.3389/fncel.2015.00144] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2015] [Accepted: 03/27/2015] [Indexed: 12/26/2022] Open
Abstract
Astrocytes are the predominant glial type in the central nervous system and play important roles in assisting neuronal function and network activity. Astrocytes exhibit complex signaling systems that are essential for their normal function and the homeostasis of the neural network. Altered signaling in astrocytes is closely associated with neurological and psychiatric diseases, suggesting tremendous therapeutic potential of these cells. To further understand astrocyte function in health and disease, it is important to study astrocytic signaling in vivo. In this review, we discuss molecular tools that enable the selective manipulation of astrocytic signaling, including the tools to selectively activate and inactivate astrocyte signaling in vivo. Lastly, we highlight a few tools in development that present strong potential for advancing our understanding of the role of astrocytes in physiology, behavior, and pathology.
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Affiliation(s)
- Alison X Xie
- Department of Pharmacology, School of Medicine, University of North Carolina at Chapel Hill Chapel Hill, NC, USA
| | - Jeremy Petravicz
- Department of Brain and Cognitive Sciences, Picower Institute for Learning and Memory, Massachusetts Institute of Technology Cambridge, MA, USA
| | - Ken D McCarthy
- Department of Pharmacology, School of Medicine, University of North Carolina at Chapel Hill Chapel Hill, NC, USA
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30
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Madasu Y, Yang C, Boczkowska M, Bethoney KA, Zwolak A, Rebowski G, Svitkina T, Dominguez R. PICK1 is implicated in organelle motility in an Arp2/3 complex-independent manner. Mol Biol Cell 2015; 26:1308-22. [PMID: 25657323 PMCID: PMC4454178 DOI: 10.1091/mbc.e14-10-1448] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
A SAXS-based structural model is described for PICK1, a key player in AMPA receptor trafficking. It is shown that the acidic C-terminal tail of PICK1 is involved in autoinhibition and motility of PICK1-associated vesicle-like structures, but, contrary to previous reports, PICK1 neither binds nor inhibits Arp2/3 complex. PICK1 is a modular scaffold implicated in synaptic receptor trafficking. It features a PDZ domain, a BAR domain, and an acidic C-terminal tail (ACT). Analysis by small- angle x-ray scattering suggests a structural model that places the receptor-binding site of the PDZ domain and membrane-binding surfaces of the BAR and PDZ domains adjacent to each other on the concave side of the banana-shaped PICK1 dimer. In the model, the ACT of one subunit of the dimer interacts with the PDZ and BAR domains of the other subunit, possibly accounting for autoinhibition. Consistently, full-length PICK1 shows diffuse cytoplasmic localization, but it clusters on vesicle-like structures that colocalize with the trans-Golgi network marker TGN38 upon deletion of either the ACT or PDZ domain. This localization is driven by the BAR domain. Live-cell imaging further reveals that PICK1-associated vesicles undergo fast, nondirectional motility in an F-actin–dependent manner, but deleting the ACT dramatically reduces vesicle speed. Thus the ACT links PICK1-associated vesicles to a motility factor, likely myosin, but, contrary to previous reports, PICK1 neither binds nor inhibits Arp2/3 complex.
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Affiliation(s)
- Yadaiah Madasu
- Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104
| | - Changsong Yang
- Department of Biology, University of Pennsylvania, Philadelphia, PA 19104
| | - Malgorzata Boczkowska
- Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104
| | - Kelley A Bethoney
- Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104
| | - Adam Zwolak
- Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104
| | - Grzegorz Rebowski
- Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104
| | - Tatyana Svitkina
- Department of Biology, University of Pennsylvania, Philadelphia, PA 19104
| | - Roberto Dominguez
- Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104
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31
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Kedracka-Krok S, Swiderska B, Jankowska U, Skupien-Rabian B, Solich J, Buczak K, Dziedzicka-Wasylewska M. Clozapine influences cytoskeleton structure and calcium homeostasis in rat cerebral cortex and has a different proteomic profile than risperidone. J Neurochem 2015; 132:657-76. [DOI: 10.1111/jnc.13007] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2014] [Revised: 11/18/2014] [Accepted: 11/25/2014] [Indexed: 12/25/2022]
Affiliation(s)
- Sylwia Kedracka-Krok
- Department of Physical Biochemistry; Faculty of Biochemistry; Biophysics and Biotechnology; Jagiellonian University; Krakow Poland
- Malopolska Centre of Biotechnology; Department of Structural Biology; Krakow Poland
| | - Bianka Swiderska
- Department of Physical Biochemistry; Faculty of Biochemistry; Biophysics and Biotechnology; Jagiellonian University; Krakow Poland
- Malopolska Centre of Biotechnology; Department of Structural Biology; Krakow Poland
| | - Urszula Jankowska
- Department of Physical Biochemistry; Faculty of Biochemistry; Biophysics and Biotechnology; Jagiellonian University; Krakow Poland
- Malopolska Centre of Biotechnology; Department of Structural Biology; Krakow Poland
| | - Bozena Skupien-Rabian
- Department of Physical Biochemistry; Faculty of Biochemistry; Biophysics and Biotechnology; Jagiellonian University; Krakow Poland
- Malopolska Centre of Biotechnology; Department of Structural Biology; Krakow Poland
| | - Joanna Solich
- Institute of Pharmacology; Polish Academy of Sciences; Krakow Poland
| | - Katarzyna Buczak
- Department of Physical Biochemistry; Faculty of Biochemistry; Biophysics and Biotechnology; Jagiellonian University; Krakow Poland
| | - Marta Dziedzicka-Wasylewska
- Department of Physical Biochemistry; Faculty of Biochemistry; Biophysics and Biotechnology; Jagiellonian University; Krakow Poland
- Institute of Pharmacology; Polish Academy of Sciences; Krakow Poland
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32
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Schweinhuber SK, Meßerschmidt T, Hänsch R, Korte M, Rothkegel M. Profilin isoforms modulate astrocytic morphology and the motility of astrocytic processes. PLoS One 2015; 10:e0117244. [PMID: 25629407 PMCID: PMC4309604 DOI: 10.1371/journal.pone.0117244] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2014] [Accepted: 12/22/2014] [Indexed: 01/17/2023] Open
Abstract
The morphology of astrocytic processes determines their close structural association with synapses referred to as the ‘tripartite synapse’. Concerted morphological plasticity processes at tripartite synapses are supposed to shape neuronal communication. Morphological changes in astrocytes as well as the motility of astrocytic processes require remodeling of the actin cytoskeleton. Among the regulators of fast timescale actin-based motility, the actin binding protein profilin 1 has recently been shown to control the activity-dependent outgrowth of astrocytic processes. Here, we demonstrate that cultured murine astrocytes in addition to the ubiquitous profilin 1 also express the neuronal isoform profilin 2a. To analyze the cellular function of both profilins in astrocytes, we took advantage of a shRNA mediated isoform-specific downregulation. Interestingly, consistent with earlier results in neurons, we found redundant as well as isoform-specific functions of both profilins in modulating cellular physiology. The knockdown of either profilin 1 or profilin 2a led to a significant decrease in cell spreading of astrocytes. In contrast, solely the knockdown of profilin 2a resulted in a significantly reduced morphological complexity of astrocytes in both dissociated and slice culture astrocytes. Moreover, both isoforms proved to be crucial for forskolin-induced astrocytic stellation. Furthermore, forskolin treatment resulted in isoform-specific changes in the phosphorylation level of profilin 1 and profilin 2a, leading to a PKA-dependent phosphorylation of profilin 2a. In addition, transwell assays revealed an involvement of both isoforms in the motility of astrocytic processes, while FRAP analysis displayed an isoform-specific role of profilin 1 in the regulation of actin dynamics in peripheral astrocytic processes. Taken together, we suggest profilin isoforms to be important modulators of astrocytic morphology and motility with overlapping as well as isoform-specific functions.
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Affiliation(s)
| | - Tania Meßerschmidt
- Cellular Neurobiology, Zoological Institute, TU Braunschweig, Braunschweig, Germany
| | - Robert Hänsch
- Molecular and Cell Biology of Plants, Institute of Plant Biology, TU Braunschweig, Braunschweig, Germany
| | - Martin Korte
- Cellular Neurobiology, Zoological Institute, TU Braunschweig, Braunschweig, Germany
| | - Martin Rothkegel
- Cellular Neurobiology, Zoological Institute, TU Braunschweig, Braunschweig, Germany
- * E-mail:
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33
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Tehrani S, Johnson EC, Cepurna WO, Morrison JC. Astrocyte processes label for filamentous actin and reorient early within the optic nerve head in a rat glaucoma model. Invest Ophthalmol Vis Sci 2014; 55:6945-52. [PMID: 25257054 DOI: 10.1167/iovs.14-14969] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE To determine if astrocyte processes label for actin and to quantify the orientation of astrocytic processes within the optic nerve head (ONH) in a rat glaucoma model. METHODS Chronic intraocular pressure (IOP) elevation was produced by episcleral hypertonic saline injection and tissues were collected after 5 weeks. For comparison, eyes with optic nerve transection were collected at 2 weeks. Fellow eyes served as controls. Axonal degeneration in retrobulbar optic nerves was graded on a scale of 1 to 5. Optic nerve head sections (n ≥ 4 eyes per group) were colabeled with phalloidin (actin marker) and antibodies to astrocytic glial fibrillary acidic protein and aquaporin 4, or axonal tubulin βIII. Confocal microscopy and FIJI software were used to quantify the orientation of actin bundles. RESULTS Control ONHs showed stereotypically arranged actin bundles within astrocyte processes. Optic nerve head actin bundle orientation was nearly perpendicular to axons (82.9° ± 6.3° relative to axonal axis), unlike the retrobulbar optic nerve (45.4° ± 28.7°, P < 0.05). With IOP elevation, ONH actin bundle orientation became less perpendicular to axons, even in eyes with no perceivable axonal injury (i.e., 38.8° ± 15.1° in grade 1, P < 0.05 in comparison to control ONHs). With severe injury, ONH actin bundle orientation became more parallel to the axonal axis (24.1° ± 28.4°, P < 0.05 in comparison to control ONHs). Optic nerve head actin bundle orientation in transected optic nerves was unchanged. CONCLUSIONS Actin labeling identifies fine astrocyte processes within the ONH. Optic nerve head astrocyte process reorientation occurs early in response to elevated IOP.
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Affiliation(s)
- Shandiz Tehrani
- Casey Eye Institute, Oregon Health & Science University, Portland, Oregon, United States
| | - Elaine C Johnson
- Casey Eye Institute, Oregon Health & Science University, Portland, Oregon, United States
| | - William O Cepurna
- Casey Eye Institute, Oregon Health & Science University, Portland, Oregon, United States
| | - John C Morrison
- Casey Eye Institute, Oregon Health & Science University, Portland, Oregon, United States
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34
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A pivotal role of nonmuscle myosin II during microglial activation. Exp Neurol 2014; 261:666-76. [PMID: 25150163 DOI: 10.1016/j.expneurol.2014.08.010] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2014] [Revised: 08/02/2014] [Accepted: 08/12/2014] [Indexed: 01/15/2023]
Abstract
Microglia are resident macrophages in the central nervous system (CNS) and the primary cells that contribute to CNS inflammation in many pathological conditions. Upon any signs of brain damage, microglia become activated and undergo tremendous cellular reorganization to adopt appropriate phenotypes. They migrate to lesion areas, accumulate, phagocytose cells or cellular debris, and produce a large array of inflammatory mediators like cytokines, chemokines, reactive oxygen species, and other mediators. To cope with the extreme cellular rearrangements during activation, microglia have to be highly dynamic. One major component of the cytoskeleton in nonmuscle cells is nonmuscle myosin II (NM II). This study was aimed to examine the functional role of NM II in resting and activated microglia. Using immunohistochemistry, we demonstrate strong expression of NM II isoform B (NM IIB) in microglia during cuprizone-induced demyelination as well as in cultured microglia. Treatment with the NM II inhibitor blebbistatin prevented the morphological shaping of microglial cells, led to functional deficits during chemokine-directed migration and phagocytosis, induced NM IIB redistribution, and affected actin microfilament patterning. In addition, inhibition of NM II led to an attenuated release of nitric oxide (NO), while TNFα secretion was not altered. In conclusion, we propose a pivotal role of NM II in cytoskeleton organization during microglial activation. This is of great importance to understand the mechanisms of microglial action in inflammatory CNS diseases.
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35
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Cui Z, Zhang J, Bao G, Xu G, Sun Y, Wang L, Chen J, Jin H, Liu J, Yang L, Feng G, Li W. Spatiotemporal profile and essential role of RBM3 expression after spinal cord injury in adult rats. J Mol Neurosci 2014; 54:252-63. [PMID: 24668366 DOI: 10.1007/s12031-014-0282-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2013] [Accepted: 03/03/2014] [Indexed: 12/15/2022]
Abstract
Hypoxia and other adverse conditions are usually encountered by rapidly growing cells. The RNA-binding motif protein 3 (RBM3) is induced by low temperature and hypoxia. However, its expression and function in spinal cord injury are still unclear. To investigate the certain expression and biological function in the central nervous system, we performed an acute spinal cord contusion injury (SCI) model in adult rats. Western blot analysis indicated a striking expression upregulation of RBM3 after spinal cord injury (SCI). Double immunofluorescence staining prompted that RBM3 immunoreactivity was found in astrocytes and neurons. Interestingly, RBM3 expression was increased predominantly in astrocytes. Furthermore, colocalization of RBM3 with proliferating cell nuclear antigen (PCNA) was detected in astrocytes. To further understand whether RBM3 plays a role in astrocyte proliferation, we applied lipopolysaccharide (LPS) to induce astrocyte proliferation in vitro. Western blot analysis demonstrated that RBM3 expression was positively correlated with PCNA expression following LPS stimulation. Immunofluorescence analysis showed that the expression of RBM3 was also changed following the stimulation of astrocytes with LPS, which was parallel with the data in vivo. Additionally, knocking RBM3 down with small interfering RNA (siRNA) demonstrated that RBM3 might play a significant role in the proliferation of astrocytes treated by hypoxia in vitro. These results suggest that RBM3 may be involved in the proliferation of astrocytes after SCI. To summarize, we firstly uncover the temporal and spatial expression changes of RBM3 in spinal cord injury. Our data suggest that RBM3 might be implicated in central nervous system pathophysiology after SCI.
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Affiliation(s)
- Zhiming Cui
- Department of Spine Surgery, The Second Affiliated Hospital of Nantong University, Nantong University, 226001, Nantong, Jiangsu, People's Republic of China,
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