1
|
Leavy A, Phelan J, Jimenez-Mateos EM. Contribution of microglia to the epileptiform activity that results from neonatal hypoxia. Neuropharmacology 2024; 253:109968. [PMID: 38692453 DOI: 10.1016/j.neuropharm.2024.109968] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2024] [Revised: 04/13/2024] [Accepted: 04/22/2024] [Indexed: 05/03/2024]
Abstract
Microglia are described as the immune cells of the brain, their immune properties have been extensively studied since first described, however, their neural functions have only been explored over the last decade. Microglia have an important role in maintaining homeostasis in the central nervous system by surveying their surroundings to detect pathogens or damage cells. While these are the classical functions described for microglia, more recently their neural functions have been defined; they are critical to the maturation of neurons during embryonic and postnatal development, phagocytic microglia remove excess synapses during development, a process called synaptic pruning, which is important to overall neural maturation. Furthermore, microglia can respond to neuronal activity and, together with astrocytes, can regulate neural activity, contributing to the equilibrium between excitation and inhibition through a feedback loop. Hypoxia at birth is a serious neurological condition that disrupts normal brain function resulting in seizures and epilepsy later in life. Evidence has shown that microglia may contribute to this hyperexcitability after neonatal hypoxia. This review will summarize the existing data on the role of microglia in the pathogenesis of neonatal hypoxia and the plausible mechanisms that contribute to the development of hyperexcitability after hypoxia in neonates. This article is part of the Special Issue on "Microglia".
Collapse
Affiliation(s)
- Aisling Leavy
- Discipline of Physiology, School of Medicine, Trinity College Dublin, The University of Dublin, Dublin, Ireland
| | - Jessie Phelan
- Discipline of Physiology, School of Medicine, Trinity College Dublin, The University of Dublin, Dublin, Ireland
| | - Eva M Jimenez-Mateos
- Discipline of Physiology, School of Medicine, Trinity College Dublin, The University of Dublin, Dublin, Ireland.
| |
Collapse
|
2
|
Mehmood A, Shah S, Guo RY, Haider A, Shi M, Ali H, Ali I, Ullah R, Li B. Methyl-CpG-Binding Protein 2 Emerges as a Central Player in Multiple Sclerosis and Neuromyelitis Optica Spectrum Disorders. Cell Mol Neurobiol 2023; 43:4071-4101. [PMID: 37955798 DOI: 10.1007/s10571-023-01432-7] [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: 08/27/2023] [Accepted: 10/27/2023] [Indexed: 11/14/2023]
Abstract
MECP2 and its product methyl-CpG binding protein 2 (MeCP2) are associated with multiple sclerosis (MS) and neuromyelitis optica spectrum disorders (NMOSD), which are inflammatory, autoimmune, and demyelinating disorders of the central nervous system (CNS). However, the mechanisms and pathways regulated by MeCP2 in immune activation in favor of MS and NMOSD are not fully understood. We summarize findings that use the binding properties of MeCP2 to identify its targets, particularly the genes recognized by MeCP2 and associated with several neurological disorders. MeCP2 regulates gene expression in neurons, immune cells and during development by modulating various mechanisms and pathways. Dysregulation of the MeCP2 signaling pathway has been associated with several disorders, including neurological and autoimmune diseases. A thorough understanding of the molecular mechanisms underlying MeCP2 function can provide new therapeutic strategies for these conditions. The nervous system is the primary system affected in MeCP2-associated disorders, and other systems may also contribute to MeCP2 action through its target genes. MeCP2 signaling pathways provide promise as potential therapeutic targets in progressive MS and NMOSD. MeCP2 not only increases susceptibility and induces anti-inflammatory responses in immune sites but also leads to a chronic increase in pro-inflammatory cytokines gene expression (IFN-γ, TNF-α, and IL-1β) and downregulates the genes involved in immune regulation (IL-10, FoxP3, and CX3CR1). MeCP2 may modulate similar mechanisms in different pathologies and suggest that treatments for MS and NMOSD disorders may be effective in treating related disorders. MeCP2 regulates gene expression in MS and NMOSD. However, dysregulation of the MeCP2 signaling pathway is implicated in these disorders. MeCP2 plays a role as a therapeutic target for MS and NMOSD and provides pathways and mechanisms that are modulated by MeCP2 in the regulation of gene expression.
Collapse
Affiliation(s)
- Arshad Mehmood
- Department of Neurology, The Second Hospital of Hebei Medical University, Shijiazhuang, 050000, Hebei, People's Republic of China
- Key Laboratory of Neurology of Hebei Province, Shijiazhuang, 050000, Hebei, People's Republic of China
| | - Suleman Shah
- Department of Cell Biology and Genetics, School of Basic Medical Sciences, Health Science Center, Shenzhen University, Shenzhen, China
| | - Ruo-Yi Guo
- Department of Neurology, The Second Hospital of Hebei Medical University, Shijiazhuang, 050000, Hebei, People's Republic of China
- Key Laboratory of Neurology of Hebei Province, Shijiazhuang, 050000, Hebei, People's Republic of China
| | - Arsalan Haider
- Key Lab of Health Psychology, Institute of Psychology, University of Chinese Academy of Sciences, Beijing, China
| | - Mengya Shi
- Department of Neurology, The Second Hospital of Hebei Medical University, Shijiazhuang, 050000, Hebei, People's Republic of China
- Key Laboratory of Neurology of Hebei Province, Shijiazhuang, 050000, Hebei, People's Republic of China
| | - Hamid Ali
- Department of Biosciences, COMSATS University Islamabad, Park Road Tarlai Kalan, Islamabad, 44000, Pakistan
| | - Ijaz Ali
- Centre for Applied Mathematics and Bioinformatics, Gulf University for Science and Technology, Hawally, 32093, Kuwait
| | - Riaz Ullah
- Medicinal Aromatic and Poisonous Plants Research Center, College of Pharmacy, King Saud University, Riyadh, Saudi Arabia
| | - Bin Li
- Department of Neurology, The Second Hospital of Hebei Medical University, Shijiazhuang, 050000, Hebei, People's Republic of China.
- Key Laboratory of Neurology of Hebei Province, Shijiazhuang, 050000, Hebei, People's Republic of China.
| |
Collapse
|
3
|
Baldassarro VA, Cescatti M, Rocco ML, Aloe L, Lorenzini L, Giardino L, Calzà L. Nerve growth factor promotes differentiation and protects the oligodendrocyte precursor cells from in vitro hypoxia/ischemia. Front Neurosci 2023; 17:1111170. [PMID: 36875668 PMCID: PMC9978228 DOI: 10.3389/fnins.2023.1111170] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2022] [Accepted: 02/02/2023] [Indexed: 02/18/2023] Open
Abstract
Introduction Nerve growth factor (NGF) is a pleiotropic molecule acting on different cell types in physiological and pathological conditions. However, the effect of NGF on the survival, differentiation and maturation of oligodendrocyte precursor cells (OPCs) and oligodendrocytes (OLs), the cells responsible for myelin formation, turnover, and repair in the central nervous system (CNS), is still poorly understood and heavily debated. Methods Here we used mixed neural stem cell (NSC)-derived OPC/astrocyte cultures to clarify the role of NGF throughout the entire process of OL differentiation and investigate its putative role in OPC protection under pathological conditions. Results We first showed that the gene expression of all the neurotrophin receptors (TrkA, TrkB, TrkC, and p75NTR ) dynamically changes during the differentiation. However, only TrkA and p75NTR expression depends on T3-differentiation induction, as Ngf gene expression induction and protein secretion in the culture medium. Moreover, in the mixed culture, astrocytes are the main producer of NGF protein, and OPCs express both TrkA and p75NTR . NGF treatment increases the percentage of mature OLs, while NGF blocking by neutralizing antibody and TRKA antagonist impairs OPC differentiation. Moreover, both NGF exposure and astrocyte-conditioned medium protect OPCs exposed to oxygenglucose deprivation (OGD) from cell death and NGF induces an increase of AKT/pAKT levels in OPCs nuclei by TRKA activation. Discussion This study demonstrated that NGF is implicated in OPC differentiation, maturation, and protection in the presence of metabolic challenges, also suggesting implications for the treatment of demyelinating lesions and diseases.
Collapse
Affiliation(s)
| | | | | | | | - Luca Lorenzini
- Department of Veterinary Medical Science, University of Bologna, Bologna, Italy
| | - Luciana Giardino
- Department of Veterinary Medical Science, University of Bologna, Bologna, Italy.,IRET Foundation, Bologna, Italy
| | - Laura Calzà
- Health Science and Technologies - Interdepartmental Center for Industrial Research (HST-ICIR), University of Bologna, Bologna, Italy.,Department of Pharmacy and Biotechnology, University of Bologna, Bologna, Italy.,Montecatone Rehabilitation Institute, Bologna, Italy
| |
Collapse
|
4
|
Kalafatakis I, Karagogeos D. Oligodendrocytes and Microglia: Key Players in Myelin Development, Damage and Repair. Biomolecules 2021; 11:1058. [PMID: 34356682 PMCID: PMC8301746 DOI: 10.3390/biom11071058] [Citation(s) in RCA: 39] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2021] [Revised: 07/16/2021] [Accepted: 07/16/2021] [Indexed: 12/13/2022] Open
Abstract
Oligodendrocytes, the myelin-making cells of the CNS, regulate the complex process of myelination under physiological and pathological conditions, significantly aided by other glial cell types such as microglia, the brain-resident, macrophage-like innate immune cells. In this review, we summarize how oligodendrocytes orchestrate myelination, and especially myelin repair after damage, and present novel aspects of oligodendroglial functions. We emphasize the contribution of microglia in the generation and regeneration of myelin by discussing their beneficial and detrimental roles, especially in remyelination, underlining the cellular and molecular components involved. Finally, we present recent findings towards human stem cell-derived preclinical models for the study of microglia in human pathologies and on the role of microbiome on glial cell functions.
Collapse
Affiliation(s)
- Ilias Kalafatakis
- Laboratory of Neuroscience, Department of Basic Science, University of Crete Medical School, 70013 Heraklion, Greece;
- IMBB FORTH, Nikolaou Plastira 100, Vassilika Vouton, 70013 Heraklion, Greece
| | - Domna Karagogeos
- Laboratory of Neuroscience, Department of Basic Science, University of Crete Medical School, 70013 Heraklion, Greece;
- IMBB FORTH, Nikolaou Plastira 100, Vassilika Vouton, 70013 Heraklion, Greece
| |
Collapse
|
5
|
Li T, Niu J, Yu G, Ezan P, Yi C, Wang X, Koulakoff A, Gao X, Chen X, Sáez JC, Giaume C, Xiao L. Connexin 43 deletion in astrocytes promotes CNS remyelination by modulating local inflammation. Glia 2019; 68:1201-1212. [PMID: 31868275 DOI: 10.1002/glia.23770] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2019] [Revised: 11/30/2019] [Accepted: 12/10/2019] [Indexed: 12/15/2022]
Abstract
As the most abundant gap junction protein in the central nervous system (CNS), astrocytic connexin 43 (Cx43) maintains astrocyte network homeostasis, affects oligodendroglial development and participates in CNS pathologies as well as injury progression. However, its role in remyelination is not yet fully understood. To address this issue, we used astrocyte-specific Cx43 conditional knockout (Cx43 cKO) mice generated through the use of a hGFAP-cre promoter, in combination with mice carrying a floxed Cx43 allele that were subjected to lysolecithin so as to induce demyelination. We found no significant difference in the demyelination of the corpus callosum between Cx43 cKO mice and their non-cre littermate controls, while the remyelination process in Cx43 cKO mice was accelerated. Moreover, an increased number of mature oligodendrocytes and an unaltered number of oligodendroglial lineage cells were found in Cx43 cKO mouse lesions. This indicates that oligodendrocyte precursor cell (OPC) differentiation was facilitated by astroglial Cx43 depletion as remyelination progressed. Underlying the latter, there was a down-regulated glial activation and modulated local inflammation as well as a reduction of myelin debris in Cx43 cKO mice. Importantly, 2 weeks of orally administrating boldine, a natural alkaloid that blocks Cx hemichannel activity in astrocytes without affecting gap junctional communication, obviously modulated local inflammation and promoted remyelination. Together, the data suggest that the astrocytic Cx43 hemichannel is negatively involved in the remyelination process by favoring local inflammation. Consequently, inhibiting Cx43 hemichannel functionality may be a potential therapeutic approach for demyelinating diseases in the CNS.
Collapse
Affiliation(s)
- Tao Li
- Department of Histology and Embryology, Institute of Brain and Intelligence, Army Medical University (Third Military Medical University), Chongqing, China
| | - Jianqin Niu
- Department of Histology and Embryology, Institute of Brain and Intelligence, Army Medical University (Third Military Medical University), Chongqing, China
| | - Guangdan Yu
- Department of Histology and Embryology, Institute of Brain and Intelligence, Army Medical University (Third Military Medical University), Chongqing, China
| | - Pascal Ezan
- Center for Interdisciplinary Research in Biology (CIRB), Collège de France, Paris, France
| | - Chenju Yi
- Seventh Affiliated Hospital of Sun Yat-sen University, Shenzhen, China
| | - Xiaorui Wang
- Department of Histology and Embryology, Institute of Brain and Intelligence, Army Medical University (Third Military Medical University), Chongqing, China
| | - Annette Koulakoff
- Center for Interdisciplinary Research in Biology (CIRB), Collège de France, Paris, France
| | - Xing Gao
- Department of Histology and Embryology, Institute of Brain and Intelligence, Army Medical University (Third Military Medical University), Chongqing, China
| | - Xianjun Chen
- Department of Histology and Embryology, Institute of Brain and Intelligence, Army Medical University (Third Military Medical University), Chongqing, China
| | - Juan C Sáez
- Departamento de Fisiología, Pontificia Universidad Católica de Chile, Santiago, Chile.,Instituto de Neurociencias, Centro Interdisciplinario de Neurociencias de Valparaíso, Valparaíso, Chile
| | - Christian Giaume
- Center for Interdisciplinary Research in Biology (CIRB), Collège de France, Paris, France
| | - Lan Xiao
- Department of Histology and Embryology, Institute of Brain and Intelligence, Army Medical University (Third Military Medical University), Chongqing, China
| |
Collapse
|
6
|
Lee YM, Sun YH. Maintenance of glia in the optic lamina is mediated by EGFR signaling by photoreceptors in adult Drosophila. PLoS Genet 2015; 11:e1005187. [PMID: 25909451 PMCID: PMC4409299 DOI: 10.1371/journal.pgen.1005187] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2014] [Accepted: 03/31/2015] [Indexed: 01/13/2023] Open
Abstract
The late onset of neurodegeneration in humans indicates that the survival and function of cells in the nervous system must be maintained throughout adulthood. In the optic lamina of the adult Drosophila, the photoreceptor axons are surrounded by multiple types of glia. We demonstrated that the adult photoreceptors actively contribute to glia maintenance in their target field within the optic lamina. This effect is dependent on the epidermal growth factor receptor (EGFR) ligands produced by the R1-6 photoreceptors and transported to the optic lamina to act on EGFR in the lamina glia. EGFR signaling is necessary and sufficient to act in a cell-autonomous manner in the lamina glia. Our results suggest that EGFR signaling is required for the trafficking of the autophagosome/endosome to the lysosome. The loss of EGFR signaling results in cell degeneration most likely because of the accumulation of autophagosomes. Our findings provide in vivo evidence for the role of adult neurons in the maintenance of glia and a novel role for EGFR signaling in the autophagic flux. Degeneration of the nervous system can be viewed as a failure to maintain cell survival or function in the nervous system. The late onset of neurodegeneration in humans indicates that the cell survival in the nervous system must be maintained throughout our lives. Neuronal survival is maintained by neurotrophic factors in adults; however, it is unclear whether glia survival is also maintained throughout adulthood. Here, we use the Drosophila visual system as a model to address the role played by adult neurons for the active maintenance of glia. We demonstrated that the adult photoreceptors secrete a signaling molecule, which is transported to the brain to act on the lamina glia and maintain its integrity. When this signaling pathway is blocked, the lamina glia undergoes a progressive and irreversible degeneration. The primary defect occurs in the trafficking from the late endosome and autophagosome to the lysosome. This defect leads to an accumulation of autophagosomes and subsequent cell degeneration as a result of autophagy. Our findings provide in vivo evidence for a novel aspect of the neuron-glia interaction and a novel role for EGFR signaling in regulating the maintenance and degeneration of the nervous system.
Collapse
Affiliation(s)
- Yuan-Ming Lee
- Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan
- Institute of Genomic Sciences, National Yang-Ming University, Taipei, Taiwan
| | - Y. Henry Sun
- Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan
- Institute of Genomic Sciences, National Yang-Ming University, Taipei, Taiwan
- * E-mail:
| |
Collapse
|
7
|
Aureli M, Grassi S, Prioni S, Sonnino S, Prinetti A. Lipid membrane domains in the brain. Biochim Biophys Acta Mol Cell Biol Lipids 2015; 1851:1006-16. [PMID: 25677824 DOI: 10.1016/j.bbalip.2015.02.001] [Citation(s) in RCA: 87] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2014] [Revised: 01/29/2015] [Accepted: 02/01/2015] [Indexed: 12/28/2022]
Abstract
The brain is characterized by the presence of cell types with very different functional specialization, but with the common trait of a very high complexity of structures originated by their plasma membranes. Brain cells bear evident membrane polarization with the creation of different morphological and functional subcompartments, whose formation, stabilization and function require a very high level of lateral order within the membrane. In other words, the membrane specialization of brain cells implies the presence of distinct membrane domains. The brain is the organ with the highest enrichment in lipids like cholesterol, glycosphingolipids, and the most recently discovered brain membrane lipid, phosphatidylglucoside, whose collective behavior strongly favors segregation within the membrane leading to the formation of lipid-driven membrane domains. Lipid-driven membrane domains function as dynamic platforms for signal transduction, protein processing, and membrane turnover. Essential events involved in the development and in the maintenance of the functional integrity of the brain depend on the organization of lipid-driven membrane domains, and alterations in lipid homeostasis, leading to deranged lipid-driven membrane organization, are common in several major brain diseases. In this review, we summarize the forces behind the formation of lipid membrane domains and their biological roles in different brain cells. This article is part of a Special Issue entitled Brain Lipids.
Collapse
Affiliation(s)
- Massimo Aureli
- Department of Medical Biotechnology and Translational Medicine, University of Milan, Italy
| | - Sara Grassi
- Department of Medical Biotechnology and Translational Medicine, University of Milan, Italy
| | - Simona Prioni
- Department of Medical Biotechnology and Translational Medicine, University of Milan, Italy
| | - Sandro Sonnino
- Department of Medical Biotechnology and Translational Medicine, University of Milan, Italy
| | - Alessandro Prinetti
- Department of Medical Biotechnology and Translational Medicine, University of Milan, Italy.
| |
Collapse
|
8
|
KhorshidAhmad T, Acosta C, Cortes C, Lakowski TM, Gangadaran S, Namaka M. Transcriptional Regulation of Brain-Derived Neurotrophic Factor (BDNF) by Methyl CpG Binding Protein 2 (MeCP2): a Novel Mechanism for Re-Myelination and/or Myelin Repair Involved in the Treatment of Multiple Sclerosis (MS). Mol Neurobiol 2015; 53:1092-1107. [PMID: 25579386 DOI: 10.1007/s12035-014-9074-1] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2014] [Accepted: 12/29/2014] [Indexed: 12/13/2022]
Abstract
Multiple sclerosis (MS) is a chronic progressive, neurological disease characterized by the targeted immune system-mediated destruction of central nervous system (CNS) myelin. Autoreactive CD4+ T helper cells have a key role in orchestrating MS-induced myelin damage. Once activated, circulating Th1-cells secrete a variety of inflammatory cytokines that foster the breakdown of blood-brain barrier (BBB) eventually infiltrating into the CNS. Inside the CNS, they become reactivated upon exposure to the myelin structural proteins and continue to produce inflammatory cytokines such as tumor necrosis factor α (TNFα) that leads to direct activation of antibodies and macrophages that are involved in the phagocytosis of myelin. Proliferating oligodendrocyte precursors (OPs) migrating to the lesion sites are capable of acute remyelination but unable to completely repair or restore the immune system-mediated myelin damage. This results in various permanent clinical neurological disabilities such as cognitive dysfunction, fatigue, bowel/bladder abnormalities, and neuropathic pain. At present, there is no cure for MS. Recent remyelination and/or myelin repair strategies have focused on the role of the neurotrophin brain-derived neurotrophic factor (BDNF) and its upstream transcriptional repressor methyl CpG binding protein (MeCP2). Research in the field of epigenetic therapeutics involving histone deacetylase (HDAC) inhibitors and lysine acetyl transferase (KAT) inhibitors is being explored to repress the detrimental effects of MeCP2. This review will address the role of MeCP2 and BDNF in remyelination and/or myelin repair and the potential of HDAC and KAT inhibitors as novel therapeutic interventions for MS.
Collapse
Affiliation(s)
- Tina KhorshidAhmad
- College of Pharmacy, University of Manitoba, 750 McDermot Avenue, Winnipeg, R3E 0T5, Manitoba, Canada.,Manitoba Multiple Sclerosis Research Network Organization (MMSRNO), Winnipeg, Canada
| | - Crystal Acosta
- College of Pharmacy, University of Manitoba, 750 McDermot Avenue, Winnipeg, R3E 0T5, Manitoba, Canada.,Manitoba Multiple Sclerosis Research Network Organization (MMSRNO), Winnipeg, Canada
| | - Claudia Cortes
- College of Pharmacy, University of Manitoba, 750 McDermot Avenue, Winnipeg, R3E 0T5, Manitoba, Canada.,Manitoba Multiple Sclerosis Research Network Organization (MMSRNO), Winnipeg, Canada
| | - Ted M Lakowski
- College of Pharmacy, University of Manitoba, 750 McDermot Avenue, Winnipeg, R3E 0T5, Manitoba, Canada.,Manitoba Multiple Sclerosis Research Network Organization (MMSRNO), Winnipeg, Canada
| | - Surendiran Gangadaran
- College of Pharmacy, University of Manitoba, 750 McDermot Avenue, Winnipeg, R3E 0T5, Manitoba, Canada.,Manitoba Multiple Sclerosis Research Network Organization (MMSRNO), Winnipeg, Canada
| | - Michael Namaka
- College of Pharmacy, University of Manitoba, 750 McDermot Avenue, Winnipeg, R3E 0T5, Manitoba, Canada. .,Manitoba Multiple Sclerosis Research Network Organization (MMSRNO), Winnipeg, Canada. .,College of Medicine, University of Manitoba, Winnipeg, Canada. .,School of Medical Rehabilitation, College of Medicine, University of Manitoba, Winnipeg, Canada.
| |
Collapse
|
9
|
Uren RT, Turbić A, Wong AW, Klein R, Murray SS, Turnley AM. A novel role of suppressor of cytokine signaling-2 in the regulation of TrkA neurotrophin receptor biology. J Neurochem 2014; 129:614-27. [PMID: 24484474 DOI: 10.1111/jnc.12671] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2013] [Revised: 01/27/2014] [Accepted: 01/28/2014] [Indexed: 12/18/2022]
Abstract
Suppressor of cytokine signaling-2 (SOCS2) is a regulator of intracellular responses to growth factors and cytokines. Cultured dorsal root ganglia neurons from neonatal mice with increased or decreased SOCS2 expression were examined for altered responsiveness to nerve growth factor (NGF). In the presence of NGF, SOCS2 over-expression increased neurite length and complexity, whereas loss of SOCS2 reduced neurite outgrowth. Neither loss nor gain of SOCS2 expression altered the relative survival of these cells, suggesting that SOCS2 can discriminate between the differentiation and survival responses to NGF. Interaction studies in 293T cells revealed that SOCS2 immunoprecipitates with TrkA and a juxtamembrane motif of TrkA was required for this interaction. SOCS2 also immunoprecipitated with endogenous TrkA in PC12 Tet-On cells. Over-expression of SOCS2 in PC12 Tet-On cells increased total and surface TrkA expression. In contrast, dorsal root ganglion neurons which over-expressed SOCS2 did not exhibit significant changes in total levels but an increase in surface TrkA was noted. SOCS2-induced neurite outgrowth in PC12 Tet-On cells correlated with increased and prolonged activation of pAKT and pErk1/2 and required an intact SOCS2 SH2 domain and SOCS box domain. This study highlights a novel role for SOCS2 in the regulation of TrkA signaling and biology.
Collapse
Affiliation(s)
- Rachel T Uren
- Department of Anatomy and Neuroscience, Centre for Neuroscience Research, The University of Melbourne, Parkville, Victoria, Australia
| | | | | | | | | | | |
Collapse
|
10
|
Abstract
A major challenge in repairing the injured spinal cord is to assure survival of damaged cells and to encourage regrowth of severed axons. Because neurotrophins are known to affect these processes during development, many experimental approaches to improving function of the injured spinal cord have made use of these agents, particularly Brain derived neurotrophic factor (BDNF) and Neurotrophin-3 (NT-3). More recently, neurotrophins have also been shown to affect the physiology of cells and synapses in the spinal cord. The effect of neurotrophins on circuit performance adds an important dimension to their consideration as agents for repairing the injured spinal cord. In this chapter we discuss the role of neurotrophins in promoting recovery after spinal cord injury from both a structural and functional perspective.
Collapse
Affiliation(s)
- Vanessa S Boyce
- Department of Neurobiology and Behavior, Stony Brook University, Stony Brook, NY, 11794-5230, USA
| | | |
Collapse
|
11
|
Schmitz M, Lüllmann K, Zafar S, Ebert E, Wohlhage M, Oikonomou P, Schlomm M, Mitrova E, Beekes M, Zerr I. Association of prion protein genotype and scrapie prion protein type with cellular prion protein charge isoform profiles in cerebrospinal fluid of humans with sporadic or familial prion diseases. Neurobiol Aging 2013; 35:1177-88. [PMID: 24360565 DOI: 10.1016/j.neurobiolaging.2013.11.010] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2013] [Revised: 10/31/2013] [Accepted: 11/10/2013] [Indexed: 01/03/2023]
Abstract
The present study investigates whether posttranslational modifications of cellular prion protein (PrP(C)) in the cerebrospinal fluid (CSF) of humans with prion diseases are associated with methionine (M) and/or valine (V) polymorphism at codon 129 of the prion protein gene (PRNP), scrapie prion protein (PrP(Sc)) type in sporadic Creutzfeldt-Jakob disease (sCJD), or PRNP mutations in familial Creutzfeldt-Jakob disease (fCJD/E200K), and fatal familial insomnia (FFI). We performed comparative 2-dimensional immunoblotting of PrP(C) charge isoforms in CSF samples from cohorts of diseased and control donors. Mean levels of total PrP(C) were significantly lower in the CSF from fCJD patients than from those with sCJD or FFI. Of the 12 most abundant PrP(C) isoforms in the examined CSF, one (IF12) was relatively decreased in (1) sCJD with VV (vs. MM or MV) at PRNP codon 129; (2) in sCJD with PrP(Sc) type 2 (vs. PrP(Sc) type 1); and (3) in FFI versus sCJD or fCJD. Furthermore, truncated PrP(C) species were detected in sCJD and control samples without discernible differences. Finally, serine 43 of PrP(C) in the CSF and brain tissue from CJD patients showed more pronounced phosphorylation than in control donors.
Collapse
Affiliation(s)
- Matthias Schmitz
- Department of Neurology, Clinical Dementia Center and DZNE Georg-August University, Göttingen, Germany.
| | - Katharina Lüllmann
- Department of Neurology, Clinical Dementia Center and DZNE Georg-August University, Göttingen, Germany
| | - Saima Zafar
- Department of Neurology, Clinical Dementia Center and DZNE Georg-August University, Göttingen, Germany
| | - Elisabeth Ebert
- Department of Neurology, Clinical Dementia Center and DZNE Georg-August University, Göttingen, Germany
| | - Marie Wohlhage
- Department of Neurology, Clinical Dementia Center and DZNE Georg-August University, Göttingen, Germany
| | - Panteleimon Oikonomou
- Department of Neurology, Clinical Dementia Center and DZNE Georg-August University, Göttingen, Germany
| | - Markus Schlomm
- Department of Neurology, Clinical Dementia Center and DZNE Georg-August University, Göttingen, Germany
| | - Eva Mitrova
- Slovak Medical University, Bratislava, Slovakia
| | - Michael Beekes
- Robert Koch-Institute, FG 14 - AG 5: Work Group Unconventional Pathogens and Their Inactivation, Division of Applied Infection Control and Nosocomial Hygiene, Berlin, Germany
| | - Inga Zerr
- Department of Neurology, Clinical Dementia Center and DZNE Georg-August University, Göttingen, Germany
| |
Collapse
|
12
|
Pang Y, Fan LW, Tien LT, Dai X, Zheng B, Cai Z, Lin RCS, Bhatt A. Differential roles of astrocyte and microglia in supporting oligodendrocyte development and myelination in vitro. Brain Behav 2013; 3:503-14. [PMID: 24392271 PMCID: PMC3869978 DOI: 10.1002/brb3.152] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/09/2013] [Revised: 05/23/2013] [Accepted: 06/08/2013] [Indexed: 12/13/2022] Open
Abstract
Oligodendrocyte (OL) development relies on many extracellular cues, most of which are secreted cytokines from neighboring neural cells. Although it is generally accepted that both astrocytes and microglia are beneficial for OL development, there is a lack of understanding regarding whether astrocytes and microglia play similar or distinct roles. The current study examined the effects of astrocytes and microglia on OL developmental phenotypes including cell survival, proliferation, differentiation, and myelination in vitro. Our data reveal that, although both astrocytes- and microglia-conditioned medium (ACDM and MCDM, respectively) protect OL progenitor cells (OPCs) against growth factor withdrawal-induced apoptosis, ACDM is significantly more effective than MCDM in supporting long-term OL survival. In contrast, MCDM preferentially promotes OL differentiation and myelination. These differential effects of ACDM and MCDM on OL development are highlighted by distinct pattern of cytokine/growth factors in the conditioned medium, which correlates with differentially activated intracellular signaling pathways in OPCs upon exposure to the conditioned medium.
Collapse
Affiliation(s)
- Yi Pang
- Department of Pediatrics, University of Mississippi Medical Center Jackson, Mississippi, 39216
| | - Lir-Wan Fan
- Department of Pediatrics, University of Mississippi Medical Center Jackson, Mississippi, 39216
| | - Lu-Tai Tien
- School of Medicine, Fu Jen Catholic University Xinzhuang Dist, New Taipei City, 24205, Taiwan
| | - Xuemei Dai
- Department of Chemistry, Jackson State University Jackson, Mississippi, 39217
| | - Baoying Zheng
- Department of Pathology, University of Mississippi Medical Center Jackson, Mississippi, 39216
| | - Zhengwei Cai
- Department of Pediatrics, University of Mississippi Medical Center Jackson, Mississippi, 39216
| | - Rick C S Lin
- Department of Neurobiology and Anatomical Sciences, University of Mississippi Medical Center Jackson, Mississippi, 39216
| | - Abhay Bhatt
- Department of Pediatrics, University of Mississippi Medical Center Jackson, Mississippi, 39216
| |
Collapse
|
13
|
Cruz CD. Neurotrophins in bladder function: what do we know and where do we go from here? Neurourol Urodyn 2013; 33:39-45. [PMID: 23775873 DOI: 10.1002/nau.22438] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2013] [Accepted: 04/30/2013] [Indexed: 12/19/2022]
Abstract
AIMS Neurotrophins (NTs) have attracted considerable attention in the urologic community. The reason for this resides in the recognition of their ability to induce plastic changes of the neuronal circuits that govern bladder function. In many pathologic states, urinary symptoms, including urgency and urinary frequency, reflect abnormal activity of bladder sensory afferents that results from neuroplastic changes. Accordingly, in pathologies associated with increased sensory input, such as the overactive bladder syndrome (OAB) or bladder pain syndrome/interstitial cystitis (BPS/IC), significant amounts of NTs have been found in the bladder wall. METHODS Here, current knowledge about the importance of NTs in bladder function will be reviewed, with a focus on the most well-studied NTs, nerve growth factor (NGF), and brain-derived neurotrophic factor (BDNF). RESULTS Both NTs are present in the bladder and regulate bladder sensory afferents and urothelial cells. Experimental models of bladder dysfunction show that upregulation of these NTs is strongly linked to bladder hyperactivity and, in some cases, pain. NT manipulation has been tested in animal models of bladder dysfunction, and recently, NGF downregulation, achieved by administration of a monoclonal antibody, has also been tested in patients with BPS/IC and chronic prostatitis/chronic pelvic pain syndrome (CP/CPPS). NTs have also been found in high quantities in the urine of OAB and BPS/IC patients, raising the possibility of NTs serving as biomarkers. CONCLUSIONS Available data show that our knowledge of NTs has greatly increased in recent years and that some results may have future clinical application.
Collapse
Affiliation(s)
- Célia Duarte Cruz
- Department of Experimental Biology, Faculty of Medicine of Porto, University of Porto, Porto, Portugal; IBMC - Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal
| |
Collapse
|
14
|
Amemori T, Romanyuk N, Jendelova P, Herynek V, Turnovcova K, Prochazka P, Kapcalova M, Cocks G, Price J, Sykova E. Human conditionally immortalized neural stem cells improve locomotor function after spinal cord injury in the rat. Stem Cell Res Ther 2013; 4:68. [PMID: 23759119 PMCID: PMC3706805 DOI: 10.1186/scrt219] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2012] [Accepted: 06/04/2013] [Indexed: 12/28/2022] Open
Abstract
Introduction A growing number of studies have highlighted the potential of stem cell and more-differentiated neural cell transplantation as intriguing therapeutic approaches for neural repair after spinal cord injury (SCI). Methods A conditionally immortalized neural stem cell line derived from human fetal spinal cord tissue (SPC-01) was used to treat a balloon-induced SCI. SPC-01 cells were implanted into the lesion 1 week after SCI. To determine the feasibility of tracking transplanted stem cells, a portion of the SPC-01 cells was labeled with poly-L-lysine-coated superparamagnetic iron-oxide nanoparticles, and the animals grafted with labeled cells underwent magnetic resonance imaging. Functional recovery was evaluated by using the BBB and plantar tests, and lesion morphology, endogenous axonal sprouting and graft survival, and differentiation were analyzed. Quantitative polymerase chain reaction (qPCR) was used to evaluate the effect of transplanted SPC-01 cells on endogenous regenerative processes. Results Transplanted animals displayed significant motor and sensory improvement 2 months after SCI, when the cells robustly survived in the lesion and partially filled the lesion cavity. qPCR revealed the increased expression of rat and human neurotrophin and motor neuron genes. The grafted cells were immunohistologically positive for glial fibrillary acidic protein (GFAP); however, we found 25% of the cells to be positive for Nkx6.1, an early motor neuron marker. Spared white matter and the robust sprouting of growth-associated protein 43 (GAP43)+ axons were found in the host tissue. Four months after SCI, the grafted cells matured into Islet2+ and choline acetyltransferase (ChAT)+ neurons, and the graft was grown through with endogenous neurons. Grafted cells labeled with poly-L-lysine-coated superparamagnetic nanoparticles before transplantation were detected in the lesion on T2-weighted images as hypointense spots that correlated with histologic staining for iron and the human mitochondrial marker MTCO2. Conclusions The transplantation of SPC-01 cells produced significant early functional improvement after SCI, suggesting an early neurotrophic action associated with long-term restoration of the host tissue, making the cells a promising candidate for future cell therapy in patients with SCI.
Collapse
|
15
|
Tanaka T, Murakami K, Bando Y, Yoshida S. Minocycline reduces remyelination by suppressing ciliary neurotrophic factor expression after cuprizone-induced demyelination. J Neurochem 2013; 127:259-70. [PMID: 23647102 DOI: 10.1111/jnc.12289] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2013] [Accepted: 04/29/2013] [Indexed: 12/29/2022]
Abstract
Remyelination is disrupted in demyelinating diseases such as multiple sclerosis, but the underlying pathogenetic mechanisms are unclear. In this study, we employed the murine cuprizone model of demyelination, in which remyelination occurs after removal of the toxin from the diet, to examine the cellular and molecular changes during demyelination and remyelination. Microglia accumulated in the corpus callosum during weeks 2-4 of the cuprizone diet, and these cells remained activated 2 weeks after the change to the normal diet. To examine the role of microglia in remyelination, mice were treated with minocycline to inactivate these cells after cuprizone-induced demyelination. Minocycline treatment reduced the number of CC1-positive oligodendrocytes, as well as levels of myelin basic protein (MBP) and CNPase in the remyelination phase. The expression of CNTF mRNA in the corpus callosum increased after 4 weeks on the cuprizone diet and remained high 2 weeks after the change to the normal diet. Minocycline suppressed CNTF expression during the remyelination phase on the normal diet. Primary culture experiments showed that CNTF was produced by microglia in addition to astrocytes. In vitro, CNTF directly affected the differentiation of oligodendrocytic cells. These findings suggest that minocycline reduces remyelination by suppressing CNTF expression by microglia after cuprizone-induced demyelination.
Collapse
Affiliation(s)
- Tatsuhide Tanaka
- Department of Functional Anatomy and Neuroscience, Asahikawa Medical University, Asahikawa, Hokkaido, Japan
| | | | | | | |
Collapse
|
16
|
Stein DG. A clinical/translational perspective: can a developmental hormone play a role in the treatment of traumatic brain injury? Horm Behav 2013; 63:291-300. [PMID: 22626570 DOI: 10.1016/j.yhbeh.2012.05.004] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/13/2012] [Revised: 05/07/2012] [Accepted: 05/08/2012] [Indexed: 01/24/2023]
Abstract
Despite decades of laboratory research and clinical trials, a safe and effective treatment for traumatic brain injury (TBI) has yet to be put into successful clinical use. I suggest that much of the problem can be attributed to a reductionist perspective and attendant research strategy directed to finding or designing drugs that target a single receptor mechanism, gene, or brain locus. This approach fails to address the complexity of TBI, which leads to a cascade of systemic toxic events in the brain and throughout the body that may persist over long periods of time. Attention is now turning to pleiotropic drugs: drugs that act on multiple genomic, proteomic and metabolic pathways to enhance morphological and functional outcomes after brain injury. Of the various agents now in clinical trials, the neurosteroid progesterone (PROG) is gaining attention despite the widespread assumption that it is "just a female hormone" with limited, if any, neuroprotective properties. This perspective should change. PROG is also a powerful developmental hormone that plays a critical role in protecting the fetus during gestation. I argue here that development, neuroprotection and cellular repair have a number of properties in common. I discuss evidence that PROG is pleiotropically neuroprotective and may be a useful therapeutic and neuroprotective agent for central nervous system injury and some neurodegenerative diseases.
Collapse
Affiliation(s)
- Donald G Stein
- Department of Emergency Medicine, Emory University, USA.
| |
Collapse
|
17
|
Yousuf S, Atif F, Sayeed I, Wang J, Stein DG. Post-stroke infections exacerbate ischemic brain injury in middle-aged rats: immunomodulation and neuroprotection by progesterone. Neuroscience 2012; 239:92-102. [PMID: 23079632 DOI: 10.1016/j.neuroscience.2012.10.017] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2012] [Revised: 09/26/2012] [Accepted: 10/05/2012] [Indexed: 01/22/2023]
Abstract
We investigated the effect of delayed, prolonged systemic inflammation on stroke outcomes and progesterone (P4) neuroprotection in middle-aged rats. After transient middle cerebral artery occlusion/reperfusion (MCAO) surgery, rats received P4 (8 or 16 mg/kg) or vehicle injections at 2h, 6h and every 24h until day 7 post-occlusion. At 24h post-injury systemic inflammation was induced by giving three doses of lipopolysaccharide (LPS; 50 μg/kg, at 4h intervals) to model post-stroke infections. We measured serum brain-derived neurotrophic factor (BDNF), pro-inflammatory cytokines, and behavioral parameters at multiple times. Serum BDNF levels decreased more in the vehicle+LPS group compared to vehicle-alone at 3 and 7 days post-injury (P<0.05). Vehicle-alone showed a significant increase in interleukin-1β, interleukin-6, and tumor necrosis factor alpha levels at different times following stroke and these levels were further elevated in the vehicle+LPS group. P4 at both doses produced a significant (P<0.05) decline in cytokine levels compared to vehicle and vehicle+LPS. P4 restored BDNF levels at 3 and 7 days post-stroke (P<0.05). Behavioral assessment (rotarod, grip strength, sensory neglect and locomotor activity tests) at 3, 5 and 7 days post-stroke revealed that the vehicle group had significant (P<0.05) deficits in all tests compared to intact controls, and performance was worse in the vehicle+LPS group. P4 at both doses produced significant functional improvement on all tests. Systemic inflammation did not show an additive effect on infarct volume but P4 at both doses showed significant infarct reduction. We suggest that post-stroke infection exacerbates stroke outcomes and P4 exerts neuroprotective/modulatory effects through its systemic anti-inflammatory and BDNF regulatory actions.
Collapse
Affiliation(s)
- S Yousuf
- Department of Emergency Medicine, Brain Research Laboratory, Emory University, Atlanta, GA 30322, USA
| | | | | | | | | |
Collapse
|
18
|
Schmitz M, Signore SC, Zerr I, Althaus HH. Oligodendroglial process formation is differentially affected by modulating the intra- and extracellular cholesterol content. J Mol Neurosci 2012; 49:457-69. [PMID: 22740150 PMCID: PMC3566395 DOI: 10.1007/s12031-012-9833-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2012] [Accepted: 06/04/2012] [Indexed: 12/12/2022]
Abstract
Cholesterol is an essential component of eukaryotic plasma membranes and plays an important role in membrane organization and signaling processes. It is the major lipid component of detergent resistant caveolin-1 containing rafts which previously had been reported as a platform for nerve growth factor (NGF) signaling in oligodendrocytes (OL). Surprisingly, a knockdown of caveolin-1 attenuated the process formation of OL (Schmitz et al. J Neurosci Res 88:572–588, 2010), for which a loss of cholesterol could be responsible. In the present report, we could show that a caveolin-1 knockdown resulted in an elevation of cellular cholesterol level; it may indicate an important role of caveolin-1 in cholesterol trafficking to the plasma membrane. Treatment with exogenous PEG cholesterol, which was incorporated to the plasma membrane, supported oligodendroglial process formation, in particular when OL were stimulated by NGF. In this context we have found that OL express NPC1L1 (Niemann–Pick disease type C1-Like 1) which could modulate cholesterol uptake. In contrast, depletion of membrane-bound cholesterol diminished NGF-induced process formation concomitant with a reduced activity of p42/44 mitogen-activated protein kinases.
Collapse
Affiliation(s)
- Matthias Schmitz
- Max-Planck Institute of Experimental Medicine, RU Neural Regeneration, Hermann-Rein-Straße 3, 37075, Goettingen, Germany.
| | | | | | | |
Collapse
|
19
|
Bartzokis G. Neuroglialpharmacology: myelination as a shared mechanism of action of psychotropic treatments. Neuropharmacology 2012; 62:2137-53. [PMID: 22306524 PMCID: PMC3586811 DOI: 10.1016/j.neuropharm.2012.01.015] [Citation(s) in RCA: 107] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2011] [Revised: 01/18/2012] [Accepted: 01/19/2012] [Indexed: 12/20/2022]
Abstract
Current psychiatric diagnostic schema segregate symptom clusters into discrete entities, however, large proportions of patients suffer from comorbid conditions that fit neither diagnostic nor therapeutic schema. Similarly, psychotropic treatments ranging from lithium and antipsychotics to serotonin reuptake inhibitors (SSRIs) and acetylcholinesterase inhibitors have been shown to be efficacious in a wide spectrum of psychiatric disorders ranging from autism, schizophrenia (SZ), depression, and bipolar disorder (BD) to Alzheimer's disease (AD). This apparent lack of specificity suggests that psychiatric symptoms as well as treatments may share aspects of pathophysiology and mechanisms of action that defy current symptom-based diagnostic and neuron-based therapeutic schema. A myelin-centered model of human brain function can help integrate these incongruities and provide novel insights into disease etiologies and treatment mechanisms. Available data are integrated herein to suggest that widely used psychotropic treatments ranging from antipsychotics and antidepressants to lithium and electroconvulsive therapy share complex signaling pathways such as Akt and glycogen synthase kinase-3 (GSK3) that affect myelination, its plasticity, and repair. These signaling pathways respond to neurotransmitters, neurotrophins, hormones, and nutrition, underlie intricate neuroglial communications, and may substantially contribute to the mechanisms of action and wide spectra of efficacy of current therapeutics by promoting myelination. Imaging and genetic technologies make it possible to safely and non-invasively test these hypotheses directly in humans and can help guide clinical trial efforts designed to correct myelination abnormalities. Such efforts may provide insights into novel avenues for treatment and prevention of some of the most prevalent and devastating human diseases.
Collapse
Affiliation(s)
- George Bartzokis
- Department of Psychiatry, The David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA.
| |
Collapse
|
20
|
Mekhail M, Almazan G, Tabrizian M. Oligodendrocyte-protection and remyelination post-spinal cord injuries: a review. Prog Neurobiol 2012; 96:322-39. [PMID: 22307058 DOI: 10.1016/j.pneurobio.2012.01.008] [Citation(s) in RCA: 84] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2011] [Revised: 01/09/2012] [Accepted: 01/19/2012] [Indexed: 12/28/2022]
Abstract
In the past four decades, the main focus of investigators in the field of spinal cord regeneration has been to devise therapeutic measures that enhance neural regeneration. More recently, emphasis has been placed on enhancing remyelination and providing oligodendrocyte-protection after a spinal cord injury (SCI). Demyelination post-SCI is part of the cascading secondary injury that takes place immediately after the primary insult; therefore, therapeutic measures are needed to reduce oligodendrocyte death and/or enhance remyelination during the acute stage, preserving neurological functions that would be lost otherwise. In this review a thorough investigation of the oligodendrocyte-protective and remyelinative molecular therapies available to date is provided. The advent of new biomaterials shown to promote remyelination post-SCI is discussed mainly in the context of a combinatorial approach where the biomaterial also provides drug delivery capabilities. The aim of these molecular and biomaterial-based therapies is twofold: (1) oligodendrocyte-protective therapy, which involves protecting already existing oligodendrocytes from undergoing apoptosis/necrosis; and (2) inductive remyelination, which involves harnessing the remyelinative capabilities of endogenous oligodendrocyte precursor cells (OPCs) at the lesion site by providing a suitable environment for their migration, survival, proliferation and differentiation. From the evidence reported in the literature, we conclude that the use of a combinatorial approach including biomaterials and molecular therapies would provide advantages such as: (1) sustained release of the therapeutic molecule, (2) local delivery at the lesion site, and (3) an environment at the site of injury that promotes OPC migration, differentiation and remyelination.
Collapse
Affiliation(s)
- Mina Mekhail
- Department of Biomedical Engineering, McGill University, Montreal, Quebec, Canada.
| | | | | |
Collapse
|
21
|
Pang Y, Zheng B, Kimberly SL, Cai Z, Rhodes PG, Lin RCS. Neuron-oligodendrocyte myelination co-culture derived from embryonic rat spinal cord and cerebral cortex. Brain Behav 2012; 2:53-67. [PMID: 22574274 PMCID: PMC3343299 DOI: 10.1002/brb3.33] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/06/2011] [Revised: 12/13/2011] [Accepted: 12/18/2011] [Indexed: 02/07/2023] Open
Abstract
An in vitro myelination model derived from rat central nervous system (CNS) remains to be established. Here, we describe a simple and reproducible myelination culture method using dissociated neuron-oligodendrocyte (OL) co-cultures from either the embryonic day 16 (E16) rat spinal cord or cerebral cortex. The dissociated cells are plated directly on poly-L-lysine-coated cover slips and maintained in a modified myelination medium that supports both OL and neuron differentiation. The spinal cord derived OL progenitor cells develop quickly into myelin basic protein (MBP)+ mature OLs and start to myelinate axons around 17 days in vitro (DIV17). Myelination reaches its peak around six weeks (DIV40) and the typical nodes of Ranvier are revealed by paranodal proteins Caspr and juxaparanodal protein Kv1.2 immunoreactivity. Electron microscopy (EM) shows typical myelination cytoarchitecture and synaptic organization. In contrast, the cortical-derived co-culture requires triiodothyronine (T3) in the culture medium for myelination. Finally, either hypomyelination and/or demyelination can be induced by exposing proinflammatory cytokines or demyelinating agents to the co-culture, suggesting the feasibility of this modified in vitro myelination model for myelin-deficit investigation.
Collapse
Affiliation(s)
- Yi Pang
- Department of Pediatrics, University of Mississippi Medical Center, Jackson, Mississippi 39216
| | - Baoying Zheng
- Department of Pathology, University of Mississippi Medical Center, Jackson, Mississippi 39216
| | - Simpson L. Kimberly
- Department of Neurobiology and Anatomical Sciences, University of Mississippi Medical Center, Jackson, Mississippi 39216
- Department of Psychiatry and Human Behavior, University of Mississippi Medical Center, Jackson, Mississippi 39216
| | - Zhengwei Cai
- Department of Pediatrics, University of Mississippi Medical Center, Jackson, Mississippi 39216
| | - Philip G. Rhodes
- Department of Pediatrics, University of Mississippi Medical Center, Jackson, Mississippi 39216
| | - Rick C. S. Lin
- Department of Neurobiology and Anatomical Sciences, University of Mississippi Medical Center, Jackson, Mississippi 39216
- Department of Psychiatry and Human Behavior, University of Mississippi Medical Center, Jackson, Mississippi 39216
| |
Collapse
|
22
|
Gudi V, Škuljec J, Yildiz Ö, Frichert K, Skripuletz T, Moharregh-Khiabani D, Voß E, Wissel K, Wolter S, Stangel M. Spatial and temporal profiles of growth factor expression during CNS demyelination reveal the dynamics of repair priming. PLoS One 2011; 6:e22623. [PMID: 21818353 PMCID: PMC3144923 DOI: 10.1371/journal.pone.0022623] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2011] [Accepted: 06/26/2011] [Indexed: 11/18/2022] Open
Abstract
Demyelination is the cause of disability in various neurological disorders. It is therefore crucial to understand the molecular regulation of oligodendrocytes, the myelin forming cells in the CNS. Growth factors are known to be essential for the development and maintenance of oligodendrocytes and are involved in the regulation of glial responses in various pathological conditions. We employed the well established murine cuprizone model of toxic demyelination to analyze the expression of 13 growth factors in the CNS during de- and remyelination. The temporal mRNA expression profile during demyelination and the subsequent remyelination were analyzed separately in the corpus callosum and cerebral cortex using laser microdissection and real-time PCR techniques. During demyelination a similar pattern of growth factor mRNA expression was observed in both areas with a strong up-regulation of NRG1 and GDNF and a slight increase of CNTF in the first week of cuprizone treatment. HGF, FGF-2, LIF, IGF-I, and TGF-ß1 were up-regulated mainly during peak demyelination. In contrast, during remyelination there were regional differences in growth factor mRNA expression levels. GDNF, CNTF, HGF, FGF-2, and BDNF were elevated in the corpus callosum but not in the cortex, suggesting tissue differences in the molecular regulation of remyelination in the white and grey matter. To clarify the cellular source we isolated microglia from the cuprizone lesions. GDNF, IGF-1, and FGF mRNA were detected in the microglial fraction with a temporal pattern corresponding to that from whole tissue PCR. In addition, immunohistochemical analysis revealed IGF-1 protein expression also in the reactive astrocytes. CNTF was located in astrocytes. This study identified seven different temporal expression patterns for growth factors in white and grey matter and demonstrated the importance of early tissue priming and exact orchestration of different steps during callosal and cortical de- and remyelination.
Collapse
Affiliation(s)
- Viktoria Gudi
- Department of Neurology, Hannover Medical School, Hannover, Germany
- Center for Systems Neuroscience, Hannover, Germany
| | - Jelena Škuljec
- Department of Neurology, Hannover Medical School, Hannover, Germany
- Center for Systems Neuroscience, Hannover, Germany
| | - Özlem Yildiz
- Department of Neurology, Hannover Medical School, Hannover, Germany
| | | | | | | | - Elke Voß
- Department of Neurology, Hannover Medical School, Hannover, Germany
| | - Kirsten Wissel
- Department of Otolaryngology, Hannover Medical School, Hannover, Germany
| | - Sabine Wolter
- Department of Pharmacology, Hannover Medical School, Hannover, Germany
| | - Martin Stangel
- Department of Neurology, Hannover Medical School, Hannover, Germany
- Center for Systems Neuroscience, Hannover, Germany
| |
Collapse
|
23
|
Effect of cavtratin, a caveolin-1 scaffolding domain peptide, on oligodendroglial signaling cascades. Cell Mol Neurobiol 2011; 31:991-7. [PMID: 21523467 PMCID: PMC3178791 DOI: 10.1007/s10571-011-9694-1] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2011] [Accepted: 04/11/2011] [Indexed: 12/11/2022]
Abstract
Caveolin and caveolin containing rafts are involved in the signaling of growth factors in various cell types. Previous reports of our lab indicated a co-localization of caveolin and the high affinity nerve growth factor (NGF) receptor tyrosine kinase A (TrkA). Mutual effects have been observed among which a caveolin-1 knock-down resulted in an impairment of the NGF signaling cascade rather than in an increase of activity as expected from other growth factor reports. On the other hand, an over-expression of caveolin-1 impaired the NGF stimulated activity of p42/44 mitogen activated protein kinases (MAPK). In this study, we used a caveolin-1 scaffolding domain (CSD) peptide (cavtratin) of which an inhibitory effect on growth factor receptors was reported. Our data showed that cavtratin suppresses the NGF-induced phosphorylation of TrkA as well as the activation of MAPK in porcine oligodendrocytes significantly.
Collapse
|
24
|
Silbereis JC, Huang EJ, Back SA, Rowitch DH. Towards improved animal models of neonatal white matter injury associated with cerebral palsy. Dis Model Mech 2011; 3:678-88. [PMID: 21030421 DOI: 10.1242/dmm.002915] [Citation(s) in RCA: 92] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Newborn neurological injuries are the leading cause of intellectual and motor disabilities that are associated with cerebral palsy. Cerebral white matter injury is a common feature in hypoxic-ischemic encephalopathy (HIE), which affects full-term infants, and in periventricular leukomalacia (PVL), which affects preterm infants. This article discusses recent efforts to model neonatal white matter injury using mammalian systems. We emphasize that a comprehensive understanding of oligodendrocyte development and physiology is crucial for obtaining new insights into the pathobiology of HIE and PVL as well as for the generation of more sophisticated and faithful animal models.
Collapse
Affiliation(s)
- John C Silbereis
- Department of Pediatrics, Eli and Edythe Broad Institute for Stem Cell Research and Regeneration Medicine, University of California San Francisco, 513 Parnassus Avenue, San Francisco, CA 94143, USA
| | | | | | | |
Collapse
|
25
|
Chen R, Hyrien O, Noble M, Mayer-Pröschel M. A composite likelihood approach to the analysis of longitudinal clonal data on multitype cellular systems under an age-dependent branching process. Biostatistics 2011; 12:173-91. [PMID: 20732974 PMCID: PMC3006127 DOI: 10.1093/biostatistics/kxq050] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2008] [Revised: 06/03/2010] [Accepted: 06/29/2010] [Indexed: 12/26/2022] Open
Abstract
A recurrent statistical problem in cell biology is to draw inference about cell kinetics from observations collected at discrete time points. We investigate this problem when multiple cell clones are observed longitudinally over time. The theory of age-dependent branching processes provides an appealing framework for the quantitative analysis of such data. Likelihood inference being difficult in this context, we propose an alternative composite likelihood approach, where the estimation function is defined from the marginal or conditional distributions of the number of cells of each observable cell type. These distributions have generally no closed-form expressions but they can be approximated using simulations. We construct a bias-corrected version of the estimating function, which also offers computational advantages. Two algorithms are discussed to compute parameter estimates. Large sample properties of the estimator are presented. The performance of the proposed method in finite samples is investigated in simulation studies. An application to the analysis of the generation of oligodendrocytes from oligodendrocyte type-2 astrocyte progenitor cells cultured in vitro reveals the effect of neurothrophin-3 on these cells. Our work demonstrates also that the proposed approach outperforms the existing ones.
Collapse
Affiliation(s)
- Rui Chen
- Department of Biostatistics and Computational Biology, University of Rochester Medical Center, 601 Elmwood Avenue, Rochester, NY 14642, USA
| | | | | | | |
Collapse
|
26
|
Schmitz M, Klöppner S, Klopfleisch S, Möbius W, Schwartz P, Zerr I, Althaus HH. Mutual effects of caveolin and nerve growth factor signaling in pig oligodendrocytes. J Neurosci Res 2010; 88:572-88. [PMID: 19795378 DOI: 10.1002/jnr.22235] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Signaling of growth factors may depend on the recruitment of their receptors to specialized microdomains. Previous reports on PC12 cells indicated an interaction of raft-organized caveolin and TrkA signaling. Because porcine oligodendrocytes (OLs) respond to nerve growth factor (NGF), we were interested to know whether caveolin also plays a role in oligodendroglial NGF/TrkA signaling. OLs expressed caveolin at the plasma membrane but also intracellularly. This was partially organized in the classically Omega-shaped invaginations, which may represent caveolae. We could show that caveolin and TrkA colocalize by using a discontinuous sucrose gradient (Song et al. [1996] J. Biol. Chem. 271:9690-9697), MACS technology, and immunoprecipitation. However, differential extraction of caveolin and TrkA with Triton X-100 at 4 degrees C indicated that caveolin and TrkA are probably not exclusively present in detergent-resistant, caveolin-containing rafts (CCRs). NGF treatment of OLs up-regulated the expression of caveolin-1 (cav-1) and stimulated tyrosine-14 phosphorylation of cav-1. Furthermore, OLs were transfected with cav-1-specific small interfering RNA (siRNA). A knockdown of cav-1 resulted in a reduced activation of downstream components of the NGF signaling cascade, such as p21Ras and mitogen-activated protein kinase (MAPK) after NGF exposure of OLs. Subsequently, increased oligodendroglial process formation via NGF was impaired. The present study indicates that CCRs/caveolin could play a modulating role during oligodendroglial differentiation and regeneration.
Collapse
Affiliation(s)
- Matthias Schmitz
- RU Neural Regeneration, Max-Planck Institute of Experimental Medicine, Goettingen, Germany.
| | | | | | | | | | | | | |
Collapse
|
27
|
Uzdensky AB, Lobanov AV. Elevated activity of the crayfish stretch receptor neuron increases resistance of surrounding glial cells to apoptosis induced by photodynamic treatment. Neurosci Lett 2010; 468:89-92. [PMID: 19879336 DOI: 10.1016/j.neulet.2009.10.072] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2009] [Revised: 10/12/2009] [Accepted: 10/22/2009] [Indexed: 10/20/2022]
Abstract
Neuroglial interaction is very important for functioning and survival of nerve and glial cells. In the present work, we studied the influence of the intense neuronal activity on survival of the isolated crayfish stretch receptor neuron and surrounding glial cells subjected to photodynamic treatment, which induces intense oxidative stress. In the experimental group, neurons were stimulated by multiple extensions of the receptor muscle for 1h so that the firing rate did not fall below 10-15 Hz, whereas in the control group, the receptor muscles were relaxed and neurons were silent. After stimulation, the preparations were photosensitized with alumophthalocyanine Photosens and irradiated by 670 nm laser diode. The isolated stretch receptors were stained with propidium iodide and Hoechst 33342, which reveal the nuclei of the necrotic and the apoptotic cells, respectively. The level of apoptosis of photosensitized glial cells was significantly lower in the experimental group compared to the resting control. Necrosis of neurons and glial cells was not significantly influenced. Therefore, elevated neuronal activity increased the resistance of the surrounding glial cells to photoinduced apoptosis. This could be attributed to the depletion of the energetic resources, which are transferred from glia into the neuron to support its firing, or to the neurotrophic neuron-to-glia signaling.
Collapse
|
28
|
Tse WKF, Eisenhaber B, Ho SHK, Ng Q, Eisenhaber F, Jiang YJ. Genome-wide loss-of-function analysis of deubiquitylating enzymes for zebrafish development. BMC Genomics 2009; 10:637. [PMID: 20040115 PMCID: PMC2809080 DOI: 10.1186/1471-2164-10-637] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2009] [Accepted: 12/30/2009] [Indexed: 02/02/2023] Open
Abstract
Background Deconjugation of ubiquitin and/or ubiquitin-like modified protein substrates is essential to modulate protein-protein interactions and, thus, signaling processes in cells. Although deubiquitylating (deubiquitinating) enzymes (DUBs) play a key role in this process, however, their function and regulation remain insufficiently understood. The "loss-of-function" phenotype studies can provide important information to elucidate the gene function, and zebrafish is an excellent model for this goal. Results From an in silico genome-wide search, we found more than 90 putative DUBs encoded in the zebrafish genome belonging to six different subclasses. Out of them, 85 from five classical subclasses have been tested with morpholino (MO) knockdown experiments and 57 of them were found to be important in early development of zebrafish. These DUB morphants resulted in a complex and pleiotropic phenotype that, regardless of gene target, always affected the notochord. Based on the huC neuronal marker expression, we grouped them into five sets (groups I to V). Group I DUBs (otud7b, uchl3 and bap1) appear to be involved in the Notch signaling pathway based on the neuronal hyperplasia, while group IV DUBs (otud4, usp5, usp15 and usp25) play a critical role in dorsoventral patterning through the BMP pathway. Conclusion We have identified an exhaustive list of genes in the zebrafish genome belonging to the five established classes of DUBs. Additionally, we performed the corresponding MO knockdown experiments in zebrafish as well as functional studies for a subset of the predicted DUB genes. The screen results in this work will stimulate functional follow-up studies of potential DUB genes using the zebrafish model system.
Collapse
Affiliation(s)
- William K F Tse
- Laboratory of Developmental Signalling and Patterning, Genes and Development Division, Institute of Molecular and Cell Biology, Agency for Science, Technology and Research, Singapore.
| | | | | | | | | | | |
Collapse
|
29
|
Protection of crayfish glial cells but not neurons from photodynamic injury by nerve growth factor. J Mol Neurosci 2009; 39:308-19. [PMID: 19381880 DOI: 10.1007/s12031-009-9199-2] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2009] [Accepted: 03/29/2009] [Indexed: 10/20/2022]
Abstract
Photodynamic treatment that causes intense oxidative stress and cell death is currently used in neurooncology. However, along with tumor cells, it may damage healthy neurons and glia. In order to study photodynamic effect on normal nerve and glial cells, we used crayfish stretch receptor, a simple system consisting of only two identified sensory neurons surrounded by glial cells. Photodynamic treatment induced firing abolition and necrosis of neurons as well as necrosis and apoptosis of glial cells. Nerve growth factor but not brain-derived neurotrophic factor or epidermal growth factor protected glial cells but not neurons from photoinduced necrosis and apoptosis. Inhibitors of tyrosine kinases or protein kinase JNK eliminated anti-apoptotic effect of nerve growth factor in photosensitized glial cells but not neurons. Therefore, these signaling proteins were involved in the anti-apoptotic activity of nerve growth factor. These data indicate the possible presence of receptors capable of recognizing murine nerve growth factor in crayfish glial cells. Thus, intercellular signaling mediated by nerve-growth-factor-like neurotrophin, receptor tyrosine kinase, and JNK may be involved in crayfish glia protection from apoptosis induced by photodynamic treatment.
Collapse
|