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Mishra D, Tiwari SK, Agarwal S, Sharma VP, Chaturvedi RK. Prenatal carbofuran exposure inhibits hippocampal neurogenesis and causes learning and memory deficits in offspring. Toxicol Sci 2012; 127:84-100. [PMID: 22240977 DOI: 10.1093/toxsci/kfs004] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Neurogenesis is a process of generation of new neurons in the hippocampus and associated with learning and memory. Carbofuran, a carbamate pesticide, elicits several neurochemical, neurophysiological, and neurobehavioral deficits. We evaluated whether chronic prenatal oral exposure of carbofuran during gestational days 7-21 alters postnatal hippocampal neurogenesis at postnatal day 21. We found carbofuran treatment significantly decreased bromodeoxyuridine (BrdU) positive cell proliferation and long-term survival in the hippocampus only but not in the cerebellum. We observed a reduced number of transcription factor SOX-2 and glial fibrillary acidic protein (GFAP) colabeled cells, decreased nestin messenger RNA (mRNA) expression, and decreased histone-H3 phosphorylation following carbofuran treatment, suggesting a decreased pool of neural progenitor cells (NPC). Colocalization of BrdU with doublecortin (DCX), neuronal nuclei (NeuN), and GFAP suggested decreased neuronal differentiation and increased glial differentiation by carbofuran. The number of DCX(+) and NeuN(+) neurons, NeuN protein levels, and fibers length of DCX(+) neurons were decreased by carbofuran. Carbofuran caused a significant downregulation of mRNA expression of the neurogenic genes/transcription factors such as neuregulin, neurogenin, and neuroD1 and upregulation of the gliogenic gene Stat3. Carbofuran exposure led to increased BrdU/caspase 3 colabeled cells, an increased number of degenerative neurons and profound deficits in learning and memory processes. The number and size of primary neurospheres derived from the hippocampus of carbofuran-treated rats were decreased. These results suggest that early gestational carbofuran exposure diminishes neurogenesis, reduces the NPC pool, produces neurodegeneration in the hippocampus, and causes cognitive impairments in rat offspring.
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Affiliation(s)
- Divya Mishra
- Developmental Toxicology Division, Systems Toxicology Group, Council of Scientific and Industrial Research-Indian Institute of Toxicology Research, Lucknow-226001, India
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Abstract
Neuregulin 1 (NRG1) is a secreted trophic factor that activates the postsynaptic erbB4 receptor tyrosine kinase. Both NRG1 and erbB4 have been repeatedly associated with schizophrenia, but their downstream targets are not well characterized. ErbB4 is highly abundant in interneurons, and NRG1-mediated erbB4 activation has been shown to modulate interneuron function, but the role for NRG1-erbB4 signaling in regulating interneuron dendritic growth is not well understood. Here we show that NRG1/erbB4 promote the growth of dendrites in mature interneurons through kalirin, a major dendritic Rac1-GEF. Recent studies have shown associations of the KALRN gene with schizophrenia. Our data point to an essential role of phosphorylation in kalirin-7's C terminus as the critical site for these effects. As reduced interneuron dendrite length occurs in schizophrenia, understanding how NRG1-erbB4 signaling modulates interneuron dendritic morphogenesis might shed light on disease-related alterations in cortical circuits.
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Woo RS, Lee JH, Kim HS, Baek CH, Song DY, Suh YH, Baik TK. Neuregulin-1 protects against neurotoxicities induced by Swedish amyloid precursor protein via the ErbB4 receptor. Neuroscience 2011; 202:413-23. [PMID: 22186019 DOI: 10.1016/j.neuroscience.2011.11.026] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2011] [Revised: 11/08/2011] [Accepted: 11/08/2011] [Indexed: 12/25/2022]
Abstract
Neuregulin-1 (NRG1) plays an important role in the development and plasticity of the brain and exhibits potent neuroprotective properties. However, little information on its role in Alzheimer's disease (AD) is known. The neuroprotective effect and mechanisms of NRG1 in SH-SY5Y cells overexpressing the Swedish mutant form of amyloid precursor protein (Swe-APP) and primary cortical neuronal cells treated with amyloid beta peptide(1-42) (Aβ(1-42)) were investigated in this study. NRG1 attenuated Swe-APP- or Aβ(1-42)-induced lactate dehydrogenase (LDH) release in a concentration-dependent manner. The mitigating effects of NRG1 on neuronal cell death were blocked by ErbB4 inhibition, a key NRG1 receptor, which suggests a role of ErbB4 in the neuroprotective function of NRG1. Moreover, NRG1 reduced the number of Swe-APP- and Aβ(1-42)-induced TUNEL-positive SH-SY5Y cells and primary cortical neurons, respectively. NRG1 reduced the accumulation of reactive oxygen species and attenuated Swe-APP-induced mitochondrial membrane potential loss. NRG1 also induced the upregulation of the expression of the anti-apoptotic protein, Bcl-2, and decreased caspase-3 activation. Collectively, our results demonstrate that NRG1 exerts neuroprotective effects via the ErbB4 receptor, which suggests the neuroprotective potential of NRG1 in AD.
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Affiliation(s)
- R-S Woo
- Department of Anatomy and Neuroscience, College of Medicine, Eulji University, Daejeon, Republic of Korea
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54
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Dysbindin-1, a schizophrenia-related protein, facilitates neurite outgrowth by promoting the transcriptional activity of p53. Mol Psychiatry 2011; 16:1105-16. [PMID: 21502952 DOI: 10.1038/mp.2011.43] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Genetic variations in the DTNBP1 gene (encoding the protein dysbindin-1) have been implicated as risk factors in the pathogenesis of schizophrenia. Previous studies have indicated that dysbindin-1 functions in the regulation of synaptic activity. Recently, dysbindin-1 has also been documented to be involved in neuronal development. In this study, we identified necdin as a binding partner of dysbindin-1 using a yeast two-hybrid screen. Dysbindin-1 recruits necdin to the cytoplasm, thereby attenuating the repressive effects of necdin on p53 transcriptional activity. Knockdown of dysbindin-1, like knockdown of p53, greatly decreases the expressions of the p53 target genes coronin 1b and rab13, which are required for neurite outgrowth. Moreover, overexpression of p53 restores the neurite outgrowth blocked by dysbindin-1 knockdown. In brains of dysbindin-1 null mice (the sandy strain), p21, Coronin 1b and Rab13 levels are reduced. Furthermore, primary cultured cortical neurons from sandy mice display neurite outgrowth defects when compared with those from wild-type mice. Thus, our data provide evidence that dysbindin-1 has an important role in neurite outgrowth through its regulation of p53's transcriptional activity.
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55
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Woo RS, Lee JH, Yu HN, Song DY, Baik TK. Expression of ErbB4 in the neurons of Alzheimer's disease brain and APP/PS1 mice, a model of Alzheimer's disease. Anat Cell Biol 2011; 44:116-27. [PMID: 21829755 PMCID: PMC3145840 DOI: 10.5115/acb.2011.44.2.116] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2011] [Revised: 04/21/2011] [Accepted: 05/02/2011] [Indexed: 01/10/2023] Open
Abstract
Neuregulin-1 (NRG1) plays important roles in the development and plasticity of the brain, and has also been reported to exhibit potent neuroprotective properties. Although ErbB4, a key NRG1 receptor, is expressed in multiple regions in the adult animal brain, little is known about its role in Alzheimer's disease (AD). AD is characterized by progressive impairment of cognition and behavioral disturbance that strongly correlate with degeneration and death of neurons in the cerebral cortex and limbic brain areas, such as the hippocampus and the amygdala. Here, we show that the ErbB4 and phospho-ErbB4 immunoreactivities were higher intensity in the neurons of the CA1-2 transitional field of AD brains as compared to age-matched controls. Also, ErbB4 expression was increased in the neurons of the cortico medial nucleus amygdala, human basal forebrain and superior frontal gyrus of AD brains. In cerebral cortex and hippocampus of amyloid precursor protein/presenilin 1 double transgenic mice, ErbB4 immunoreactivity significantly increased in comparison to age-matched wild type control. These results suggest that up-regulating of ErbB4 immunoreactivity may involve in the progression of pathology of AD.
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Affiliation(s)
- Ran-Sook Woo
- Department of Anatomy and Neuroscience, College of Medicine, Eulji University, Daejeon, Korea
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56
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Neuregulin-1β Prevents Ca2+ Overloading and Apoptosis Through PI3K/Akt Activation in Cultured Dorsal Root Ganglion Neurons with Excitotoxicity Induced by Glutamate. Cell Mol Neurobiol 2011; 31:1195-201. [DOI: 10.1007/s10571-011-9721-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2011] [Accepted: 05/30/2011] [Indexed: 10/18/2022]
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Gerecke KM, Kishore R, Jasnow A, Quadros-Menella P, Parker S, Kozub FJ, Lambert KG, Kinsley CH. Alterations of sex-typical microanatomy: prenatal stress modifies the structure of medial preoptic area neurons in rats. Dev Psychobiol 2011; 54:16-27. [PMID: 21656762 DOI: 10.1002/dev.20570] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2010] [Accepted: 04/26/2011] [Indexed: 11/06/2022]
Abstract
Prenatal stress disrupts normal sexual differentiation and behavior with concomitant alterations in brain development; however, its effects on the cytoarchitecture of neurons in the sexually dimorphic medial preoptic area (mPOA) of the hypothalamus is not known. Morphometric analysis of the mPOA of adult rats showed sex differences as neurons from control females had significantly greater numbers of basal dendritic branches and cumulative basal dendritic length as compared to control male neurons. Prenatal stress significantly altered these sexual dimorphisms, as prenatally stressed (P-S) males had increased measures of cell body area, perimeter, cumulative basal dendritic length, and branch point numbers as compared to control males. Prenatal stress also altered the cytoarchitecture in the female mPOA neurons as P-S female neurons had significantly greater measures for primary dendritic branch number and a trend towards significance for several additional measures as compared to control females. Therefore, there are significant effects of both sex and prenatal stress on neuronal architecture in the mPOA that may help to explain the well-documented alterations in reproductive behaviors observed in P-S animals.
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Affiliation(s)
- Kim M Gerecke
- Department of Psychology, Rhodes College, 2000 N. Parkway, Memphis, TN 38112, USA.
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58
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Pan B, Huang XF, Deng C. Antipsychotic treatment and neuregulin 1-ErbB4 signalling in schizophrenia. Prog Neuropsychopharmacol Biol Psychiatry 2011; 35:924-30. [PMID: 21513767 DOI: 10.1016/j.pnpbp.2011.04.002] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/25/2011] [Revised: 03/18/2011] [Accepted: 04/03/2011] [Indexed: 12/17/2022]
Abstract
Evidence from genetic, transgenic and post-mortem studies has strongly supported the critical role that neuregulin 1 (NRG1) and its ErbB4 receptor plays in the pathophysiology of schizophrenia. This article aims to review current evidence regarding the effects of antipsychotic treatment on NRG1-ErbB4 signalling. NRG1 and ErbB4 knockout mice display abnormal behaviours relevant to certain features of schizophrenia, which could be improved by antipsychotic (clozapine/haloperidol) treatment. In contrast to most NRG1/ErbB4 knockout mice with a decreased NRG1-ErbB4 signalling, the majority post-mortem studies showed an increased NRG1-ErbB4 signalling in schizophrenic patients. These differences could be due to degrees of alteration in risk genes (subtle variations in patients vs pronounced alteration in mutant mice) or the duration of the modification on NRG1 signalling. Various antipsychotics have different effects on NRG1 and ErbB4 expression and signalling that are dependent on treatment duration. Current evidence suggests that a chronic (12weeks) antipsychotic treatment, at least in animal models, could downregulate NRG1-ErbB4 signalling, although an upregulation is seen for a short-term treatment. These effects may be due to multiple binding profiles with various G-coupled protein receptors (e.g. dopamine, and serotonin receptors) of antipsychotics. Studies are needed to investigate the interactions between NRG1-ErbB4 and the other signalling pathways (such as glutamatergic, GABAergic and dopaminergic). Furthermore, the interactions between NRG1/ErbB4 and other schizophrenia suspensibility genes under antipsychotic treatment also require investigation.
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Affiliation(s)
- Bo Pan
- Centre for Translational Neuroscience, School of Health Sciences, University of Wollongong, Wollongong, 2522 NSW, Australia
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59
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Liu Z, Gao W, Wang Y, Zhang W, Liu H, Li Z. Neuregulin-1β regulates outgrowth of neurites and migration of neurofilament 200 neurons from dorsal root ganglial explants in vitro. Peptides 2011; 32:1244-8. [PMID: 21515322 DOI: 10.1016/j.peptides.2011.04.005] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/05/2011] [Revised: 04/04/2011] [Accepted: 04/07/2011] [Indexed: 01/05/2023]
Abstract
Neuregulin-1β (NRG-1β) signaling has multiple functions in neurons. To assess NRG-1β on neurite outgrowth and neuronal migration in vitro, organotypic dorsal root ganglion (DRG) neuronal culture model was established. Neurite outgrowth and neuronal migration were evaluated using this culture model in the presence (5nmol/L, 10nmol/L, 20nmol/L) or absence of NRG-1β. Neurofilament 200 (NF-200)-immunoreactive (IR) neurons were determined as the migrating neurons. The number of nerve fiber bundles extended from DRG explant increased significantly in the presence of NRG-1β (5nmol/L, 23.0±2.2, P<0.05; 10nmol/L, 27.0±2.7, P<0.001; 20nmol/L, 30.8±3.7, P<0.001) as compared with that in the absence of NRG-1β (19.0±2.2). The number of neurons migrating from DRG explants increased significantly in the presence of NRG-1β (5nmol/L, 39.6±5.0, P<0.05; 10nmol/L, 54.6±6.7, P<0.001; 20nmol/L, 62.2±5.7, P<0.001) as compared with that in the absence of NRG-1β (31.6±4.0). Moreover, the increase of the number of nerve fiber bundles and the number of migrating NF-200-IR neurons was dose-dependent for NRG-1β addition. The data in this study imply that NRG-1β promotes neurite outgrowth and neuronal migration from DRG explants in vitro.
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Affiliation(s)
- Zhen Liu
- Department of Anatomy, Shandong University School of Medicine, 44 Wenhua Xi Road, Jinan, Shandong Province 250012, China
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60
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Zhang J, Zhao F, Wu G, Li Y, Jin X. Functional and histological improvement of the injured spinal cord following transplantation of Schwann cells transfected with NRG1 gene. Anat Rec (Hoboken) 2011; 293:1933-46. [PMID: 20734425 DOI: 10.1002/ar.21223] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
In this study, we implanted Schwann cells (SCs) transfected with Neuregulin 1 (NRG1) gene into rats with hemisection spinal cord injury, determined its effects on the repair of spinal cord injury and investigated the underlying mechanisms. Primary SCs were cultured, purified, and transfected with NRG1 gene. SCs and SCs transfected with NRG1 gene were implanted, respectively, into rats with hemisection spinal cord injury. Behavior, imaging, electrophysiology, and immuno-histological analyses were performed to evaluate the effect of NRG1 gene-transfected SCs on the repair of spinal cord injury. In vitro studies showed that NRG1 protein was highly expressed in SCs transfected with NRG1 gene. In addition, the receptors for NRG1, ErbB2, and ErbB4, were upregulated in a time-dependent manner. NRG1-transfected SCs secreted large amount of NRG1 proteins in vivo, which efficiently promoted the expression of ErbB2 and ErbB4 in the neurons and neuroglia cells. Moreover, the number of NSE- and GFAP-positive cells was increased. After cell transplantation, many transplanted cells survived and migrated to the areas with spinal cord injuries. The injuries were recovered in all the experimental groups, but the most significant recovery was observed in the group of rats implanted with SCs transfected with NRG1 gene. We conclude that NRG1-transfected SCs can significantly increase the effect on the repair of spinal cord injury. This repair effect is achieved via the upregulation of ErbB receptor in the target cells, increased proliferation of glial cells, and protection of neurons from apoptosis.
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Affiliation(s)
- Jifei Zhang
- Department of Histoembryology, Medical College of Mudanjiang, Mudanjiang City, Heilongjiang Province, China
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61
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Joung I, Yoo M, Woo JH, Chang CY, Heo H, Kwon YK. Secretion of EGF-like domain of heregulinβ promotes axonal growth and functional recovery of injured sciatic nerve. Mol Cells 2010; 30:477-84. [PMID: 20957456 DOI: 10.1007/s10059-010-0137-5] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2010] [Accepted: 08/16/2010] [Indexed: 01/12/2023] Open
Abstract
Neuregulin 1 (NRG1) and epidermal growth factor receptor (ErbB) signaling pathways control Schwann cells during axonal regeneration in an injured peripheral nervous system. We investigated whether a persistent supply of recombinant NRG1 to the injury site could improve axonal growth and recovery of sensory and motor functions in rats during nerve regeneration. We generated a recombinant adenovirus expressing a secreted form of EGF-like domain from Heregulinβ (sHRGβE-Ad). This virus, sHRGβE-Ad allowed for the secretion of 30-50 ng of small sHRGβE peptides per 10(7-8) virus particle outside cells and was able to phosphorylate ErbB receptors. Transduction of the concentrated sHRGβE-Ad into an axotomy model of sciatic nerve damage caused an effective promotion of nerve regeneration, as shown by histological features of the axons and Schwann cells, as well as increased expression of neurofilaments, GAP43 and S100 in the distal stump of the injury site. This result is consistent with longer axon lengths and thicker calibers observed in the sHRGβE-Ad treated animals. Furthermore, sensory and motor functions were significantly improved in sHRGβE-Ad treated animals when evaluated by a behavioral test. These results suggest a therapeutic potential for sHRGβE-Ad in treatment of peripheral nerve injury.
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Affiliation(s)
- Insil Joung
- Department of Biological Sciences, Hanseo University, Seosan, 352-820, Korea
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62
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Jeanneteau F, Deinhardt K, Miyoshi G, Bennett AM, Chao MV. The MAP kinase phosphatase MKP-1 regulates BDNF-induced axon branching. Nat Neurosci 2010; 13:1373-9. [PMID: 20935641 PMCID: PMC2971689 DOI: 10.1038/nn.2655] [Citation(s) in RCA: 128] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2010] [Accepted: 09/08/2010] [Indexed: 12/20/2022]
Abstract
The refinement of neural circuits during development depends upon a dynamic process of branching of axons and dendrites that leads to synapse formation and connectivity. The neurotrophin BDNF plays an essential role in the outgrowth and activity-dependent remodeling of axonal arbors in vivo. However, the mechanisms that translate extracellular signals into axonal branch formation are incompletely understood. Here we report that the MAP kinase phosphatase-1 (MKP-1) controls axon branching. MKP-1 expression induced by BDNF signaling exerts spatio-temporal deactivation of JNK, which negatively regulates the phosphorylation of JNK substrates that impinge upon microtubule destabilization. Indeed, neurons from mkp-1 null mice were unable to produce axon branches in response to BDNF. Our results indicate a heretofore-unknown signaling mechanism to regulate axonal branching and provide a framework for studying the molecular mechanism of innervation and axonal remodeling under normal and pathological conditions.
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Affiliation(s)
- Freddy Jeanneteau
- Molecular Neurobiology Program, Skirball Institute of Biomolecular Medicine, New York, New York, USA.
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63
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Intramembranous valine linked to schizophrenia is required for neuregulin 1 regulation of the morphological development of cortical neurons. J Neurosci 2010; 30:9199-208. [PMID: 20610754 DOI: 10.1523/jneurosci.0605-10.2010] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Neuregulin 1 (NRG1) signaling is critical to various aspects of neuronal development and function. Among different NRG1 isoforms, the type III isoforms of NRG1 are unique in their ability to signal via the intracellular domain after gamma-secretase-dependent intramembranous processing. However, the functional consequences of type III NRG1 signaling via its intracellular domain are mostly unknown. In this study, we have identified mutations within type III NRG1 that disrupt intramembranous proteolytic processing and abolish intracellular domain signaling. In particular, substitutions at valine 321, previously linked to schizophrenia risks, result in NRG1 proteins that fail to undergo gamma-secretase-mediated nuclear localization and transcriptional activation. Using processing-defective mutants of type III NRG1, we demonstrate that the intracellular domain signaling is specifically required for NRG1 regulation of the growth and branching of cortical dendrites but not axons. Consistent with the role of type III NRG1 signaling via the intracellular domain in the initial patterning of cortical dendrites, our findings from pharmacological and genetic studies indicate that type III NRG1 functions in dendritic development independent of ERBB kinase activity. Together, these results support the proposal that aberrant intramembranous processing and defective signaling via the intracellular domain of type III NRG1 impair a subset of NRG1 functions in cortical development and contribute to abnormal neuroconnectivity implicated in schizophrenia.
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64
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Hoffmann I, Bueter W, Zscheppang K, Brinkhaus MJ, Liese A, Riemke S, Dörk T, Dammann O, Dammann CEL. Neuregulin-1, the fetal endothelium, and brain damage in preterm newborns. Brain Behav Immun 2010; 24:784-91. [PMID: 19733651 PMCID: PMC2885532 DOI: 10.1016/j.bbi.2009.08.012] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/03/2009] [Revised: 08/25/2009] [Accepted: 08/26/2009] [Indexed: 12/16/2022] Open
Abstract
OBJECTIVE To assess the potential role for Neuregulin-1 (NRG1) as a systemic endogenous protector in the setting of perinatal inflammatory brain damage. METHODS We measured NRG1-protein and mRNA levels in human umbilical venous endothelial cells (HUVECs) of different gestational ages at various durations of exposure to lipopolysaccharide (LPS). In parallel, we genotyped the donor individuals for SNP8NRG221533, a disease-related single nucleotide polymorphism in the 5' region upstream of the NRG1 sequence. Intracellular NRG1 localization was visualized by confocal microscopy. Furthermore we analyzed the relationship between SNP8NRG221533 genotype and neurodevelopmental outcome in children born preterm. RESULTS We observed a positive dose-response-relationship between NRG1-mRNA and intracellular protein levels with both advancing gestational age and duration of LPS exposure in HUVECs. The presence of allele C at the SNP8NRG221533 locus was associated with an increased cellular production of NRG1 in HUVECs, and with a significantly reduced risk for cerebral palsy and developmental delay in children born preterm. INTERPRETATION In conclusion, our data indicate that gestational age, duration of LPS exposure, and the SNP8NRG221533 genotype affect NRG1 levels. Our results support the hypothesis that NRG1 may qualify as an endogenous protector during fetal development.
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Affiliation(s)
- Insa Hoffmann
- Pediatric Pulmonology and Neonatology, Hannover Medical School, Hannover, Germany
| | - Wolfgang Bueter
- Perinatal Neuroepidemiology Unit, Hannover Medical School, Hannover, Germany
| | - Katja Zscheppang
- Pediatric Pulmonology and Neonatology, Hannover Medical School, Hannover, Germany
| | | | - Andrea Liese
- Pediatric Pulmonology and Neonatology, Hannover Medical School, Hannover, Germany
| | - Stefan Riemke
- Perinatal Neuroepidemiology Unit, Hannover Medical School, Hannover, Germany
| | - Thilo Dörk
- Gynecology and Obstetrics, Hannover Medical School, Hannover, Germany
| | - Olaf Dammann
- Perinatal Neuroepidemiology Unit, Hannover Medical School, Hannover, Germany,Newborn Medicine, Floating Hospital for Children at Tufts Medical Center, Boston, MA, USA,Neuroepidemiology Unit, Children's Hospital, Boston, MA, USA
| | - Christiane E. L. Dammann
- Pediatric Pulmonology and Neonatology, Hannover Medical School, Hannover, Germany,Newborn Medicine, Floating Hospital for Children at Tufts Medical Center, Boston, MA, USA
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65
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Shamir A, Buonanno A. Molecular and cellular characterization of Neuregulin-1 type IV isoforms. J Neurochem 2010; 113:1163-76. [PMID: 20218976 DOI: 10.1111/j.1471-4159.2010.06677.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Numerous genetic studies associated the Neuregulin 1 (NRG1) Icelandic haplotype (HAP(ice)), and its single nucleotide polymorphism SNP8NRG243177 [T/T], with schizophrenia. Because SNP8NRG243177 [T/T] has characteristics of a functional polymorphism that maps close to NRG1 type IV coding sequences, our initial goal was to map precisely the human type IV transcription initiation site. We determined that the initiation site is 23 bp upstream of the previously reported type IV exon, and that no other transcripts map to the SNP8NRG243177 region. Because NRG1 type IV transcripts are specific to human, we isolated full-length NRG1 type IV cDNAs from human hippocampi and expressed them in non-neural cells and dissociated rat hippocampal neurons to study protein expression, processing and function. Using an antiserum we generated against the NRG1 type IV-specific N-terminus, we found that the protein is targeted to the cell surface where PKC activation promotes its cleavage and release of the extracellular domain. Conditioned medium derived from type IV expressing cells stimulates ErbB receptor phosphorylation, as well as downstream Akt and Erk signaling, demonstrating that NRG1 type IV possesses biological activity similar to other releasable NRG1 isoforms. To study the subcellular targeting of distinct isoforms, neurons were transfected with the Ig-domain-containing NRG1 types I and IV, or the cysteine-rich domain type III isoform. Three dimensional confocal images from transfected neurons indicate that, whereas all isoforms are expressed on somato-dendritic membranes, only the type III-cysteine-rich domain isoform is detectable in distal axons. These results suggest that NRG1 type IV expression levels associated with SNP8NRG243177 [T/T] can selectively modify signaling of NRG1 released from somato-dendritic compartments, in contrast to the type III NRG1 that is also associated with axons.
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Affiliation(s)
- Alon Shamir
- Section on Molecular Neurobiology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, Maryland 20892, USA
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66
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Harrill JA, Freudenrich TM, Machacek DW, Stice SL, Mundy WR. Quantitative assessment of neurite outgrowth in human embryonic stem cell-derived hN2 cells using automated high-content image analysis. Neurotoxicology 2010; 31:277-90. [PMID: 20188755 DOI: 10.1016/j.neuro.2010.02.003] [Citation(s) in RCA: 89] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2009] [Revised: 02/09/2010] [Accepted: 02/17/2010] [Indexed: 02/04/2023]
Abstract
Throughout development neurons undergo a number of morphological changes including neurite outgrowth from the cell body. Exposure to neurotoxic chemicals that interfere with this process may result in permanent deficits in nervous system function. Traditionally, rodent primary neural cultures and immortalized human and non-human clonal cell lines have been used to investigate the molecular mechanisms controlling neurite outgrowth and examine chemical effects on this process. The present study characterizes the molecular phenotype of hN2 human embryonic stem cell (hESC)-derived neural cells and uses automated high-content image analysis to measure neurite outgrowth in vitro. At 24h post-plating hN2 cells express a number of protein markers indicative of a neuronal phenotype, including: nestin, beta(III)-tubulin, microtubule-associated protein 2 (MAP2) and phosphorylated neurofilaments. Neurite outgrowth in hN2 cells proceeded rapidly, with a majority of cells extending one to three neurites by 48h in culture. In addition, concentration-dependent decreases in neurite outgrowth and ATP-content were observed following treatment of hN2 cells with either bisindolylmaleimide I, U0126, lithium chloride, sodium orthovanadate and brefeldin A, all of which have previously been shown to inhibit neurite outgrowth in primary rodent neural cultures. Overall, the molecular phenotype, rate of neurite outgrowth and sensitivity of hN2 cells to neurite outgrowth inhibitors were comparable to other in vitro models previously characterized in the literature. hN2 cells provide a model in which to investigate chemical effects on neurite outgrowth in a non-transformed human-derived cells and provide an alternative to the use of primary rodent neural cultures or immortalized clonal cell lines.
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Affiliation(s)
- Joshua A Harrill
- Systems Biology Branch, Integrated Systems Toxicology Division, National Health and Environmental Effects Research Laboratory, United States Environmental Protection Agency, Research Triangle Park, NC 27711, United States
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67
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Kuai L, Wang X, Madison JM, Schreiber SL, Scolnick EM, Haggarty SJ. Chemical genetics identifies small-molecule modulators of neuritogenesis involving neuregulin-1/ErbB4 signaling. ACS Chem Neurosci 2010; 1:325-342. [PMID: 20495671 DOI: 10.1021/cn900046a] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Genetic findings have suggested that neuregulin-1 (Nrg1) and its receptor v-erb-a erythroblastic leukemia viral oncogene homolog 4 (ErbB4) may play a role in neuropsychiatric diseases. However, the downstream signaling events and relevant phenotypic consequences of altered Nrg1 signaling in the nervous system remain poorly understood. To identify small molecules for probing Nrg1-ErbB4 signaling, a PC12-cell model was developed and used to perform a live-cell, image-based screen of the effects of small molecules on Nrg1-induced neuritogenesis. By comparing the resulting phenotypic data to that of a similar screening performed with nerve growth factor (NGF), this multidimensional screen identified compounds that directly inhibit Nrg1-ErbB4 signaling, such as the 4-anilino-quinazoline Iressa (gefitinib), as well as compounds that potentiate Nrg1-ErbB4 signaling, such as the indolocarbazole K-252a. These findings provide new insights into the regulation of Nrg1-ErbB4 signaling events and demonstrate the feasibility of using such a multidimensional, chemical-genetic approach for discovering probes of pathways implicated in neuropsychiatric diseases.
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Affiliation(s)
- Letian Kuai
- Stanley Center for Psychiatric Research, Broad Institute of Harvard and MIT, 7 Cambridge Center, Cambridge, Massachusetts 02142
| | - Xiang Wang
- Department of Chemistry and Biochemistry, University of Colorado, 215 UCB, Boulder, Colorado 80309
| | - Jon M. Madison
- Stanley Center for Psychiatric Research, Broad Institute of Harvard and MIT, 7 Cambridge Center, Cambridge, Massachusetts 02142
| | - Stuart L. Schreiber
- Chemical Biology Program, Broad Institute of Harvard and MIT, 7 Cambridge Center, Cambridge, Massachusetts 02142
| | - Edward M. Scolnick
- Stanley Center for Psychiatric Research, Broad Institute of Harvard and MIT, 7 Cambridge Center, Cambridge, Massachusetts 02142
| | - Stephen J. Haggarty
- Stanley Center for Psychiatric Research, Broad Institute of Harvard and MIT, 7 Cambridge Center, Cambridge, Massachusetts 02142
- Center for Human Genetic Research, Massachusetts General Hospital, Department of Neurology, Harvard Medical School, 185 Cambridge Street, Boston, Massachusetts 02114
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68
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Dickerson JW, Hemmerle AM, Numan S, Lundgren KH, Seroogy KB. Decreased expression of ErbB4 and tyrosine hydroxylase mRNA and protein in the ventral midbrain of aged rats. Neuroscience 2009; 163:482-9. [PMID: 19505538 DOI: 10.1016/j.neuroscience.2009.06.008] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2009] [Revised: 06/03/2009] [Accepted: 06/04/2009] [Indexed: 10/20/2022]
Abstract
Decreased availability or efficacy of neurotrophic factors may underlie an increased susceptibility of mesencephalic dopaminergic cells to age-related degeneration. Neuregulins (NRGs) are pleotrophic growth factors for many cell types, including mesencephalic dopamine cells in culture and in vivo. The functional NRG receptor ErbB4 is expressed by virtually all midbrain dopamine neurons. To determine if levels of the NRG receptor are maintained during aging in the dopaminergic ventral mesencephalon, expression of ErbB4 mRNA and protein was examined in young (3 months), middle-aged (18 months), and old (24-25 months) Brown Norway/Fischer 344 F1 rats. ErbB4 mRNA levels in the substantia nigra pars compacta (SNpc), but not the adjacent ventral tegmental area (VTA) or subtantia nigra pars lateralis (SNl), were significantly reduced in the middle-aged and old animals when compared to young rats. Protein expression of ErbB4 in the ventral midbrain was significantly decreased in the old rats when compared to the young rats. Expression of tyrosine hydroxylase (TH) mRNA levels was significantly reduced in the old rats when compared to young animals in the SNpc, but not in the VTA or SNI. TH protein levels in the ventral midbrain were also decreased in the old animals when compared to the young animals. These data demonstrate a progressive decline of ErbB4 expression, coinciding with a loss of the dopamine-synthesizing enzyme TH, in the ventral midbrain of aged rats, particularly in the SNpc. These findings may implicate a role for diminished NRG/ErbB4 trophic support in dopamine-related neurodegenerative disorders of aging such as Parkinson's disease.
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Affiliation(s)
- J W Dickerson
- Department of Neurology, College of Medicine, University of Cincinnati, Cincinnati, OH 45267, USA
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69
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Chu CT, Plowey ED, Dagda RK, Hickey RW, Cherra SJ, Clark RSB. Autophagy in neurite injury and neurodegeneration: in vitro and in vivo models. Methods Enzymol 2009; 453:217-49. [PMID: 19216909 DOI: 10.1016/s0076-6879(08)04011-1] [Citation(s) in RCA: 99] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Recent advances indicate that maintaining a balanced level of autophagy is critically important for neuronal health and function. Pathologic dysregulation of macroautophagy has been implicated in synaptic dysfunction, cellular stress, and neuronal cell death. Autophagosomes and autolysosomes are induced in acute and chronic neurological disorders including stroke, brain trauma, neurotoxin injury, Parkinson's, Alzheimer's, Huntington's, motor neuron, prion, lysosomal storage, and other neurodegenerative diseases. Compared to other cell types, neuronal autophagy research presents particular challenges that may be addressed through still evolving techniques. Neuronal function depends upon maintenance of axons and dendrites (collectively known as neurites) that extend for great distances from the cell body. Both autophagy and mitochondrial content have been implicated in regulation of neurite length and function in physiological (plasticity) and pathological remodeling. Here, we highlight several molecular cell biological and imaging methods to study autophagy and mitophagy in neuritic and somatic compartments of differentiated neuronal cell lines and primary neuron cultures, using protocols developed in toxic and genetic models of parkinsonian neurodegeneration. In addition, mature neurons can be studied using in vivo protocols for modeling ischemic and traumatic injuries. Future challenges include application of automated computer-assisted image analysis to the axodendritic tree of individual neurons and improving methods for measuring neuronal autophagic flux.
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Affiliation(s)
- Charleen T Chu
- Department of Pathology, Division of Neuropathology, University of Pittsburgh School of Medicine and Center for Neuroscience, Pittsburgh, Pennsylvania, USA
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70
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Freese C, Garratt AN, Fahrenholz F, Endres K. The effects of alpha-secretase ADAM10 on the proteolysis of neuregulin-1. FEBS J 2009; 276:1568-80. [PMID: 19220854 DOI: 10.1111/j.1742-4658.2009.06889.x] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Although ADAM10 is a major alpha-secretase involved in non-amyloidogenic processing of the amyloid precursor protein, several additional substrates have been identified, most of them in vitro. Thus, therapeutical approaches for the prevention of Alzheimer's disease by upregulation of this metalloproteinase may have severe side effects. In the present study, we examined whether the ErbB receptor ligand neuregulin-1, which is essential for myelination and other important neuronal functions, is cleaved by ADAM10. Studies with beta- and gamma-secretase inhibitors, as well as with the metalloproteinase inhibitor GM6001, revealed an inhibition of neuregulin-1 processing in human astroglioma cell line U373; however, specific RNA interference-induced knockdown of ADAM10 remained without effect. In vivo investigations of mice overexpressing either ADAM10 or dominant negative ADAM10 showed unaltered cleavage of neuregulin-1 compared to wild-type animals. As a consequence, the myelin sheath thickness of peripheral nerves was unaffected in mice with altered ADAM10 activity. Thus, although the beta-secretase BACE-1 acts as a neuregulin-1 sheddase, ADAM10 does not lead to altered neuregulin-1 processing either in cell culture or in vivo. Adverse reactions of an ADAM10-based therapy of Alzheimer's disease due to neuregulin-1 cleavage are therefore unlikely.
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Affiliation(s)
- Christian Freese
- Institute of Biochemistry, Johannes Gutenberg-University, Mainz, Germany
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71
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Gruber O, Falkai P, Schneider-Axmann T, Schwab SG, Wagner M, Maier W. Neuregulin-1 haplotype HAP(ICE) is associated with lower hippocampal volumes in schizophrenic patients and in non-affected family members. J Psychiatr Res 2008; 43:1-6. [PMID: 18291420 DOI: 10.1016/j.jpsychires.2008.01.009] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/06/2007] [Revised: 01/02/2008] [Accepted: 01/02/2008] [Indexed: 01/31/2023]
Abstract
The neuregulin-1 (NRG1) gene on chromosome 8p has been suggested as a potential susceptibility gene for schizophrenia. The exact way in which genetic variation in NRG1 might impact on this susceptibility for the disorder is a focus of current research. The present study aimed at investigating the possible relationship between a putative NRG1 at-risk haplotype (HAP(ICE)) and hippocampal volumes in schizophrenic patients and their healthy first-degree relatives. We genotyped 30 schizophrenic patients and 52 non-affected family members with regard to the presence or absence of the NRG1 haplotype HAP(ICE). Structural magnetic resonance imaging was used to determine hippocampal brain volumes in the same subjects. Patients and relatives carrying haplotype HAP(ICE) both had smaller relative hippocampal volumes as compared to patients or relatives who did not carry this haplotype. These findings provide first direct evidence for a link between NRG1 genetic variation and hippocampal volume reductions in schizophrenic patients and non-affected relatives. This preliminary evidence may help to guide further research into the pathophysiological pathways that underlie this genetic susceptibility for schizophrenia.
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Affiliation(s)
- Oliver Gruber
- Department of Psychiatry and Psychotherapy, Georg August University, Goettingen, Germany.
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72
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Neuregulin 1 in neural development, synaptic plasticity and schizophrenia. Nat Rev Neurosci 2008; 9:437-52. [PMID: 18478032 DOI: 10.1038/nrn2392] [Citation(s) in RCA: 778] [Impact Index Per Article: 48.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Schizophrenia is a highly debilitating mental disorder that affects approximately 1% of the general population, yet it continues to be poorly understood. Recent studies have identified variations in several genes that are associated with this disorder in diverse populations, including those that encode neuregulin 1 (NRG1) and its receptor ErbB4. The past few years have witnessed exciting progress in our knowledge of NRG1 and ErbB4 functions and the biological basis of the increased risk for schizophrenia that is potentially conferred by polymorphisms in the two genes. An improved understanding of the mechanisms by which altered function of NRG1 and ErbB4 contributes to schizophrenia might eventually lead to the development of more effective therapeutics.
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73
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Murphy SP, Bielby-Clarke K. Neuregulin signaling in neurons depends on ErbB4 interaction with PSD-95. Brain Res 2008; 1207:32-5. [DOI: 10.1016/j.brainres.2008.02.063] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2007] [Revised: 02/11/2008] [Accepted: 02/18/2008] [Indexed: 01/08/2023]
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74
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Ozog MA, Modha G, Church J, Reilly R, Naus CC. Co-administration of Ciliary Neurotrophic Factor with Its Soluble Receptor Protects against Neuronal Death and Enhances Neurite Outgrowth. J Biol Chem 2008; 283:6546-60. [DOI: 10.1074/jbc.m709065200] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
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75
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Wang P, Jeng CJ, Chien CL, Wang SM. Signaling mechanisms of daidzein-induced axonal outgrowth in hippocampal neurons. Biochem Biophys Res Commun 2008; 366:393-400. [DOI: 10.1016/j.bbrc.2007.11.147] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2007] [Accepted: 11/22/2007] [Indexed: 11/24/2022]
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76
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Hamel MG, Ajmo JM, Leonardo CC, Zuo F, Sandy JD, Gottschall PE. Multimodal signaling by the ADAMTSs (a disintegrin and metalloproteinase with thrombospondin motifs) promotes neurite extension. Exp Neurol 2007; 210:428-40. [PMID: 18178186 DOI: 10.1016/j.expneurol.2007.11.014] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2007] [Revised: 11/01/2007] [Accepted: 11/16/2007] [Indexed: 01/03/2023]
Abstract
Aggregating proteoglycans (PG) bearing chondroitin sulfate (CS) side chains associate with hyaluronan and various secreted proteins to form a complex of extracellular matrix (ECM) that inhibits neural plasticity in the central nervous system (CNS). Chondroitinase treatment depletes PGs of their CS side chains and enhances neurite extension. Increasing evidence from in vivo models indicates that proteolytic cleavage of the PG core protein by members of the ADAMTS (a disintegrin and metalloproteinase with thrombospondin motifs) family of glutamyl-endopeptidases also promotes neural plasticity. The purpose of this study was to determine whether proteolytic action of the ADAMTSs influences neurite outgrowth in cultured neurons. Transfection of primary rat neurons with ADAMTS4 cDNA induced longer neurites, whether the neurons were grown on a monolayer of astrocytes that secrete inhibitory PGs or on laminin/poly-L-lysine substrate alone. Similar results were found when neurons were transfected with a construct encoding a proteolytically inactive, point mutant of ADAMTS4. Addition of recombinant ADAMTS4 or ADAMTS5 protein to immature neuronal cultures also enhanced neurite extension in a dose-dependent manner, an effect demonstrated to be dependent on the activation of MAP ERK1/2 kinase. These results suggest that ADAMTS4 enhances neurite outgrowth via a mechanism that does not require proteolysis but is dependent on activation of the MAP kinase cascade. Thus a model to illustrate multimodal ADAMTS activity would entail proteolysis of CS-bearing PGs to create a loosened matrix environment more favorable for neurite outgrowth, and enhanced neurite outgrowth directly stimulated by ADAMTS signaling at the cell surface.
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Affiliation(s)
- Michelle G Hamel
- University of South Florida College of Medicine, Department of Molecular Pharmacology & Physiology, 12901 Bruce B. Downs Boulevard, Tampa, FL 33612-4799, USA
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77
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Mei L, Xiong WC. Neuregulin-1 signaling in schizophrenia. FUTURE NEUROLOGY 2007. [DOI: 10.2217/14796708.2.5.477] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Affiliation(s)
- Lin Mei
- Medical College of Georgia, Program of Developmental Neurobiology, Institute of Molecular Medicine & Genetics, Department of Neurology, Augusta, GA 30912, USA
| | - Wen-Cheng Xiong
- Medical College of Georgia, Program of Developmental Neurobiology, Institute of Molecular Medicine & Genetics, Department of Neurology, Augusta, GA 30912, USA
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78
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Nie S, Chang C. PI3K and Erk MAPK mediate ErbB signaling in Xenopus gastrulation. Mech Dev 2007; 124:657-67. [PMID: 17716876 PMCID: PMC2098746 DOI: 10.1016/j.mod.2007.07.005] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2007] [Revised: 06/18/2007] [Accepted: 07/12/2007] [Indexed: 12/22/2022]
Abstract
ErbB signaling regulates cell adhesion and movements during Xenopus gastrulation, but the downstream pathways involved have not been elucidated. In this study, we show that phosphatidylinositol-3 kinase (PI3K) and Erk mitogen-activated protein kinase (MAPK) mediate ErbB signaling to regulate gastrulation. Both PI3K and MAPK function sequentially in mesoderm specification and movements, and ErbB signaling is important only for the late phase activation of these pathways to control cell behaviors. Activation of either PI3K or Erk MAPK rescues gastrulation defects in ErbB4 morphant embryos, and restores convergent extension in the trunk mesoderm as well as coherent cell migration in the head mesoderm. The two signals preferentially regulate different aspects of cell behaviors, with PI3K more efficient in rescuing cell adhesion and spreading and MAPK more effective in stimulating the formation of filopodia. PI3K and MAPK also weakly activate each other, and together they modulate gastrulation movements. Our results reveal that PI3K and Erk MAPK, which have previously been considered as mesodermal inducing signals, also act downstream of ErbB signaling to participate in regulation of gastrulation morphogenesis.
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Affiliation(s)
| | - Chenbei Chang
- correspondent, ; 205-975-7229 (phone); 205-975-5648 (fax)
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79
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Moore CD, Thacker EE, Larimore J, Gaston D, Underwood A, Kearns B, Patterson SI, Jackson T, Chapleau C, Pozzo-Miller L, Theibert A. The neuronal Arf GAP centaurin alpha1 modulates dendritic differentiation. J Cell Sci 2007; 120:2683-93. [PMID: 17635995 PMCID: PMC2810648 DOI: 10.1242/jcs.006346] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Centaurin alpha1 is an Arf GTPase-activating protein (GAP) that is highly expressed in the nervous system. In the current study, we show that endogenous centaurin alpha1 protein is localized in the synaptosome fraction, with peak expression in early postnatal development. In cultured dissociated hippocampal neurons, centaurin alpha1 localizes to dendrites, dendritic spines and the postsynaptic region. siRNA-mediated knockdown of centaurin alpha1 levels or overexpression of a GAP-inactive mutant of centaurin alpha1 leads to inhibition of dendritic branching, dendritic filopodia and spine-like protrusions in dissociated hippocampal neurons. Overexpression of wild-type centaurin alpha1 in cultured hippocampal neurons in early development enhances dendritic branching, and increases dendritic filopodia and lamellipodia. Both filopodia and lamellipodia have been implicated in dendritic branching and spine formation. Following synaptogenesis in cultured neurons, wild-type centaurin alpha1 expression increases dendritic filopodia and spine-like protrusions. Expression of a GAP-inactive mutant diminishes spine density in CA1 pyramidal neurons within cultured organotypic hippocampal slice cultures. These data support the conclusion that centaurin alpha1 functions through GAP-dependent Arf regulation of dendritic branching and spines that underlie normal dendritic differentiation and development.
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Affiliation(s)
- Carlene D. Moore
- Department of Neurobiology and Civitan International Research Center, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Erin E. Thacker
- Department of Neurobiology and Civitan International Research Center, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Jennifer Larimore
- Department of Neurobiology and Civitan International Research Center, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - David Gaston
- Department of Neurobiology and Civitan International Research Center, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Alison Underwood
- Department of Neurobiology and Civitan International Research Center, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Brian Kearns
- Department of Neurobiology and Civitan International Research Center, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Sean I. Patterson
- IHEM-CONICET, Departmento de Morfo-Fisiología, Facultad de Ciencias Médicas, Universidad Nacional de Cuyo, Mendoza, Argentina
| | - Trevor Jackson
- Departments of Physiology and Dermatology, School of Clinical and Laboratory Sciences, Medical School, University of Newcastle upon Tyne, NE2 4HH, UK
| | - Chris Chapleau
- Department of Neurobiology and Civitan International Research Center, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Lucas Pozzo-Miller
- Department of Neurobiology and Civitan International Research Center, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Anne Theibert
- Department of Neurobiology and Civitan International Research Center, University of Alabama at Birmingham, Birmingham, AL 35294, USA
- Author for correspondence ()
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80
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Li B, Woo RS, Mei L, Malinow R. The neuregulin-1 receptor erbB4 controls glutamatergic synapse maturation and plasticity. Neuron 2007; 54:583-97. [PMID: 17521571 PMCID: PMC2031848 DOI: 10.1016/j.neuron.2007.03.028] [Citation(s) in RCA: 274] [Impact Index Per Article: 16.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2006] [Revised: 02/15/2007] [Accepted: 03/29/2007] [Indexed: 11/16/2022]
Abstract
Neuregulin-1 (NRG1) signaling participates in numerous neurodevelopmental processes. Through linkage analysis, nrg1 has been associated with schizophrenia, although its pathophysiological role is not understood. The prevailing models of schizophrenia invoke hypofunction of the glutamatergic synapse and defects in early development of hippocampal-cortical circuitry. Here, we show that the erbB4 receptor, as a postsynaptic target of NRG1, plays a key role in activity-dependent maturation and plasticity of excitatory synaptic structure and function. Synaptic activity leads to the activation and recruitment of erbB4 into the synapse. Overexpressed erbB4 selectively enhances AMPA synaptic currents and increases dendritic spine size. Preventing NRG1/erbB4 signaling destabilizes synaptic AMPA receptors and leads to loss of synaptic NMDA currents and spines. Our results indicate that normal activity-driven glutamatergic synapse development is impaired by genetic deficits in NRG1/erbB4 signaling leading to glutamatergic hypofunction. These findings link proposed effectors in schizophrenia: NRG1/erbB4 signaling perturbation, neurodevelopmental deficit, and glutamatergic hypofunction.
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Affiliation(s)
- Bo Li
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724, USA
| | - Ran-Sook Woo
- Program of Developmental Neurobiology and Department of Neurology, Institute of Molecular Medicine and Genetics, Medical College of Georgia, Augusta, Georgia 30912, USA
| | - Lin Mei
- Program of Developmental Neurobiology and Department of Neurology, Institute of Molecular Medicine and Genetics, Medical College of Georgia, Augusta, Georgia 30912, USA
| | - Roberto Malinow
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724, USA
- * Corresponding Author, e-mail:
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81
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Mechawar N, Lacoste B, Yu WF, Srivastava LK, Quirion R. Developmental profile of neuregulin receptor ErbB4 in postnatal rat cerebral cortex and hippocampus. Neuroscience 2007; 148:126-39. [PMID: 17630218 DOI: 10.1016/j.neuroscience.2007.04.066] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2006] [Revised: 04/09/2007] [Accepted: 04/12/2007] [Indexed: 01/29/2023]
Abstract
We investigated the cellular and subcellular distributions of neuregulin tyrosine kinase receptor ErbB4 in the postnatal rat frontal cortex and hippocampus by light-, confocal- and electron-microscopic immunocytochemistry. At birth, ErbB4-immunoreactivity (ErbB4-IR) was prominent in the apical cytoplasm and dendrites of cortical plate neurons and hippocampal pyramidal cells. Throughout postnatal development and in adulthood, ErbB4-IR in both regions remained confined to the somatodendritic compartment of neurons, which increased in number to reach the adult pattern by the end of the first postnatal month (P30). At all ages examined, double-labeling experiments revealed that ErbB4-IR always co-localized with the neuronal marker neuronal nuclei (NeuN) and never with glial markers Nestin or glial fibrillary acidic protein (GFAP). Immunoperoxidase labeling at the ultrastructural level confirmed the exclusive localization of ErbB4-IR in somatodendrites, and notably in dendritic spines. Immunogold labeling showed preponderant ErbB4-IR in the cytoplasm, where it was associated with microtubules. Furthermore, ErbB4-IR was abundant in the nucleus of adult cortical and hippocampal neurons, suggesting a role for ErbB4 nuclear signaling in the brain beyond embryonic development. Taken together, these results show that ErbB4 is expressed by neuronal somatodendrites in cerebral cortex and hippocampus from birth to adulthood, and support a role for neuregulins in dendritic growth and plasticity.
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Affiliation(s)
- N Mechawar
- Douglas Hospital Research Centre, McGill University, Department of Psychiatry, 6875 LaSalle Boulevard, Verdun, Montréal, Québec, Canada H4H 1R3.
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82
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LaCroix-Fralish ML, Tawfik VL, Spratt KF, DeLeo JA. Sex differences in lumbar spinal cord gene expression following experimental lumbar radiculopathy. J Mol Neurosci 2007; 30:283-95. [PMID: 17401154 DOI: 10.1385/jmn:30:3:283] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/1999] [Revised: 11/30/1999] [Accepted: 11/30/1999] [Indexed: 01/07/2023]
Abstract
Considerable evidence indicates that there are sex-related differences in clinical and experimental pain sensitivity. In the present study, we sought to determine what genes were expressed in the spinal cord in a sexually dimorphic manner. We first analyzed global gene expression in the lumbar spinal cord of uninjured male and female rats using the Affymetrix RAE230A GeneChip platform in order to identify genes that are selectively expressed in male and female rats at a basal level. We subsequently analyzed global gene expression in the lumbar spinal cord of male and female rats at two time points (7 days and 14 d) following a rodent model of lumbar radiculopathy (L5 nerve root ligation) in order to determine what genes were regulated in a sexually dimorphic manner following nerve root injury. We utilized a linear regression analysis method to identify genes that were significantly different from the corresponding sham surgical controls. The expression patterns of several genes of interest were subsequently confirmed using RT-PCR. Our findings demonstrate significant differences in lumbar spinal cord gene expression in both uninjured and injured (L5 nerve root ligation) male and female rats. Further confirmation of a subset of the genes identified Neuregulin 1 and its high affinity receptor, ErbB4, Tachykinin 1, and Metabotropic glutamate receptor 6 as female specific genes upregulated following L5 nerve root injury. These findings provide several target genes for further study that may elucidate the neurochemical mechanisms underlying sex differences in pain sensitivity and lead to improved treatments for chronic pain syndromes.
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83
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Lein PJ, Guo X, Shi GX, Moholt-Siebert M, Bruun D, Andres DA. The novel GTPase Rit differentially regulates axonal and dendritic growth. J Neurosci 2007; 27:4725-36. [PMID: 17460085 PMCID: PMC3495986 DOI: 10.1523/jneurosci.5633-06.2007] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
The Rit GTPase is widely expressed in developing and adult nervous systems, and our previous data with pheochromocytoma cells implicate Rit signaling in NGF-induced neurite outgrowth. In this study, we investigated a role for Rit in neuronal morphogenesis. Expression of a dominant-negative (dn) Rit mutant in hippocampal neurons inhibited axonal growth but potentiated dendritic growth. Conversely, a constitutively active (ca) Rit mutant promoted axonal growth but inhibited dendritic growth. Dendritogenesis is regulated differently in sympathetic neurons versus hippocampal neurons in that sympathetic neurons require NGF and bone morphogenetic proteins (BMPs) to trigger dendritic growth. Despite these differences, dnRit potentiated and caRit blocked BMP7-induced dendritic growth in sympathetic neurons. Biochemical studies indicated that BMP7 treatments that caused dendritic growth also decreased Rit GTP loading. Additional studies demonstrate that caRit increased extracellular signal-regulated kinase 1/2 (ERK1/2) phosphorylation and pharmacological inhibition of MEK1 (mitogen-activated protein kinase/ERK 1) blocked the axon-promoting and dendrite-inhibiting effects of caRit. These observations suggest that Rit is a convergence point for multiple signaling pathways and it functions to promote axonal growth but inhibit dendritic growth via activation of ERK1/2. Modulation of the activational status of Rit may therefore represent a generalized mechanism across divergent neuronal cell types for regulating axonal versus dendritic growth modes.
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Affiliation(s)
- Pamela J Lein
- Center for Research on Occupational and Environmental Toxicology, Oregon Health & Science University, Portland, Oregon 97239, USA.
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84
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Lacroix-Fralish ML, Tawfik VL, Nutile-McMenemy N, Deleo JA. Neuregulin 1 is a pronociceptive cytokine that is regulated by progesterone in the spinal cord: implications for sex specific pain modulation. Eur J Pain 2007; 12:94-103. [PMID: 17459743 DOI: 10.1016/j.ejpain.2007.03.010] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2006] [Revised: 02/01/2007] [Accepted: 03/11/2007] [Indexed: 11/15/2022]
Abstract
Sex differences in the magnitude of response to thermal and tactile stimuli have been demonstrated in both clinical and animal studies. Females typically display lower threshold responses to painful stimuli as compared to males. We have previously observed sexually dimorphic expression of the growth factor, neuregulin 1 (NRG1) following L5 nerve root ligation (LR) in male and female rats. In the present study, we sought to determine which gonadal hormones were involved in regulating NRG1 expression following L5 nerve root ligation. We observed that expression of NRG1 mRNA and the neuregulin receptors, ErbB2 and ErbB4 in the lumbar spinal cord was facilitated by the presence of progesterone in female rats following L5 nerve root ligation. An increase in NRG1 protein and NRG1 immunoreactivity was also observed in the ipsilateral spinal cord of progesterone treated female rats as compared to ovariectomized female rats and male rats at day 14 following LR. NRG1 immunoreactivity was equally colocalized with either the astrocytic marker, GFAP, and with NeuN labeled neurons 14days following L5 nerve root ligation. Intrathecal administration of recombinant NRG1-beta1 protein significantly decreased the hindpaw tactile withdrawal threshold in male rats, ovariectomized female rats, and progesterone treated female rats. These results demonstrate a role for progesterone-dependent regulation of glial and/or neuronal neuregulin 1 in female rats in mediating sex differences in nociception. Furthermore, our results suggest that NRG1 may be involved in central sensitization during the maintenance phase, but not in the initiation of persistent pain in female rats.
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85
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Liu Y, Tao YM, Woo RS, Xiong WC, Mei L. Stimulated ErbB4 internalization is necessary for neuregulin signaling in neurons. Biochem Biophys Res Commun 2007; 354:505-10. [PMID: 17250808 PMCID: PMC2696396 DOI: 10.1016/j.bbrc.2007.01.009] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2006] [Accepted: 01/03/2007] [Indexed: 11/24/2022]
Abstract
Neuregulin-1 (NRG1) plays an important role in neural development, synapse formation, and synaptic plasticity by activating ErbB receptor tyrosine kinases. Although ligand-induced endocytosis has been shown to be important for many receptor tyrosine kinases, whether NRG1 signaling depends on ErbB endocytosis remains controversial. Here, we provide evidence that ErbB4, a prominent ErbB protein in the brain, becomes internalized in NRG1-stimulated neurons. The induced ErbB4 endocytosis requires its kinase activity. Remarkably, inhibition of ErbB endocytosis attenuates NRG1-induced activation of Erk and Akt in neurons. These observations indicate a role of ErbB endocytosis in NRG1 signaling in neurons.
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Affiliation(s)
- Yu Liu
- Program of Developmental Neurobiology, Institute of Molecular Medicine and Genetics, Department of Neurology, Medical College of Georgia, Augusta GA 30912, USA
- Department of Radiochemotherapy, Zhongnan Hospital of Wuhan University, Wuhan, Hubei, 430071, P. R. China
| | - Yan-Mei Tao
- Program of Developmental Neurobiology, Institute of Molecular Medicine and Genetics, Department of Neurology, Medical College of Georgia, Augusta GA 30912, USA
| | - Ran-Sook Woo
- Program of Developmental Neurobiology, Institute of Molecular Medicine and Genetics, Department of Neurology, Medical College of Georgia, Augusta GA 30912, USA
| | - Wen-Cheng. Xiong
- Program of Developmental Neurobiology, Institute of Molecular Medicine and Genetics, Department of Neurology, Medical College of Georgia, Augusta GA 30912, USA
| | - Lin Mei
- Program of Developmental Neurobiology, Institute of Molecular Medicine and Genetics, Department of Neurology, Medical College of Georgia, Augusta GA 30912, USA
- Corresponding author. Fax: +1 706 721 8685. E-mail address: (L. Mei)
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86
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Bertram I, Bernstein HG, Lendeckel U, Bukowska A, Dobrowolny H, Keilhoff G, Kanakis D, Mawrin C, Bielau H, Falkai P, Bogerts B. Immunohistochemical Evidence for Impaired Neuregulin-1 Signaling in the Prefrontal Cortex in Schizophrenia and in Unipolar Depression. Ann N Y Acad Sci 2007; 1096:147-56. [PMID: 17405926 DOI: 10.1196/annals.1397.080] [Citation(s) in RCA: 89] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
In the central nervous system (CNS), neuregulin-1 (NRG-1) proteins function in neuronal migration, differentiation, and survival of oligodendrocytes. The NRG-1 gene codes for at least 15 different isoforms, which may be classified on the basis of their molecular structure. At least two different haplotypes of the NRG-1 gene may be associated with schizophrenia. An abnormal expression pattern of NRG-1 mRNA was found in the prefrontal cortex of schizophrenic patients in comparison to controls. We here show that the NRG-1alpha isoform is significantly reduced in white matter of the prefrontal cortex in schizophrenia but not in affective disorder. In the prefrontal gray matter, the density of NRG-1alpha expressing neurons was reduced in individuals with schizophrenia and in unipolar patients. We studied brains of 22 schizophrenics, 12 patients with affective disorders (7 unipolar and 5 bipolar), and 22 matched controls. NRG-1alpha immunoreactive material was detected with a polyclonal antiserum against the synthetic peptide from alpha-type EGF-like domain of human NRG. The demonstrated decreased number of NRG-1 immunoreactive neurons in the brains of schizophrenics and patients with unipolar depression points to an important role of this NRG-1alpha splice variant in neuropsychiatric disorders. Reduced NRG-1alpha protein concentrations were found in brains of schizophrenics after Western blot analysis. The diminished expression of NRG-1alpha strongly supports an early neurodevelopmental component to schizophrenia.
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Affiliation(s)
- Iris Bertram
- Exp. Psychiatry Lab., University of Magdeburg, Leipziger Str. 44, D-39120 Magdeburg, Germany
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87
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Carter CJ. Schizophrenia susceptibility genes converge on interlinked pathways related to glutamatergic transmission and long-term potentiation, oxidative stress and oligodendrocyte viability. Schizophr Res 2006; 86:1-14. [PMID: 16842972 DOI: 10.1016/j.schres.2006.05.023] [Citation(s) in RCA: 89] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/24/2005] [Revised: 05/22/2006] [Accepted: 05/27/2006] [Indexed: 10/24/2022]
Abstract
Over 130 genes have been associated with schizophrenia in genetic studies. None of these has reached a sufficient level of confidence to be accepted as a universal susceptibility gene and problems of replicability suggest that many may be false positives. Nevertheless, these genes can be grouped into distinct families related to glutamate transmission (in particular related to NMDA receptor function), the control of synaptic plasticity, dopaminergic transmission, oxidative stress, glutathione and quinone metabolism and oligodendrocyte viability. These families mirror the processes disrupted in the schizophrenic brain and certain gene families can be linked together to form a clearly defined signalling cascade involved in the phenomenon of NMDA receptor-dependent long-term potentiation and synaptic plasticity, that may be interconnected with oligodendrocyte and oxidative stress-related pathways. Many of the protein products of these genes interact with each other, forming complex integrated networks. Certain high-interest genes (for example DISC1, NRG1, COMT) may exert multiple effects on different areas of these pathways, while others exert more specific effects on certain branches. The convergence of a large number of genes on a definable signaling network raises the possibility of numerous interactions between gene candidates, and suggests that a targeted multigenic pathway approach would be useful in gene association studies.
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88
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Esper RM, Pankonin MS, Loeb JA. Neuregulins: Versatile growth and differentiation factors in nervous system development and human disease. ACTA ACUST UNITED AC 2006; 51:161-75. [PMID: 16412517 DOI: 10.1016/j.brainresrev.2005.11.006] [Citation(s) in RCA: 114] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2005] [Revised: 11/02/2005] [Accepted: 11/04/2005] [Indexed: 12/29/2022]
Abstract
The neuregulins are a family of growth and differentiation factors with a wide range of functions in the nervous system. The power and diversity of the neuregulin signaling system comes in part from a large number of alternatively-spliced forms of the NRG1 gene that can produce both soluble and membrane-bound forms. The soluble forms of neuregulin are unique from other factors in that they have a structurally distinct heparin-binding domain that targets and potentiates its actions. In addition, a finely tuned, bidirectional mechanism regulates when and where neuregulin is released from neurons in response to neurotrophic factors produced by both neuronal targets and supporting glial cells. Together, this produces a balanced intercellular signaling system that can be localized to distinct regions for both normal development and maintenance of the mature nervous system. Recent evidence suggests that neuregulin signaling plays important roles in many neurological disorders including multiple sclerosis, traumatic brain and spinal cord injury, peripheral neuropathy, and schizophrenia. Here, we review the basic biology of neuregulins and relate this to research suggesting their involvement with and potential therapeutic uses for neurological disorders.
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Affiliation(s)
- Raymond M Esper
- Department of Neurology, Wayne State University, Detroit, MI 48201, USA
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89
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Harrison PJ, Law AJ. Neuregulin 1 and schizophrenia: genetics, gene expression, and neurobiology. Biol Psychiatry 2006; 60:132-40. [PMID: 16442083 DOI: 10.1016/j.biopsych.2005.11.002] [Citation(s) in RCA: 361] [Impact Index Per Article: 20.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/30/2005] [Revised: 11/14/2005] [Accepted: 11/22/2005] [Indexed: 12/23/2022]
Abstract
Neuregulin 1 (NRG1) is a leading schizophrenia susceptibility gene. The NRG1 locus on chromosome 8p shows linkage to the disorder, and genetic association has been found between schizophrenia and various non-coding polymorphisms and haplotypes, especially at the 5' end of the NRG1 gene, in many but not all case-control and family studies. NRG1 is a pleiotropic growth factor, important in nervous system development and functioning; roles include the modulation of neuronal migration, synaptogenesis, gliogenesis, neuron-glia communication, myelination, and neurotransmission. Understanding the neurobiology of NRG1 and its involvement in schizophrenia is challenged by the complexity of the gene, which gives rise to multiple functionally distinct isoforms, including six "types" of NRG1 defined by 5' exon usage. Type IV and type I NRG1 may be particularly relevant to schizophrenia, with initial data showing altered expression of these isoforms in the disorder or in association with NRG1 risk alleles. We review the structure and functions of NRG1, consider the evidence for and against it being a schizophrenia susceptibility gene, and discuss mechanisms that might underlie the contribution of NRG1 to disease pathophysiology.
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Affiliation(s)
- Paul J Harrison
- Department of Psychiatry, University of Oxford, Warneford Hospital, Oxford, United Kingdom.
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90
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Rieff HI, Corfas G. ErbB receptor signalling regulates dendrite formation in mouse cerebellar granule cells in vivo. Eur J Neurosci 2006; 23:2225-9. [PMID: 16630068 DOI: 10.1111/j.1460-9568.2006.04727.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The formation of morphologically and functionally mature dendrites is a key event in neuronal maturation and the establishment of functional neuronal networks, but the signals that regulate mammalian dendritic development remain poorly understood. Here we show that the erbB receptor signalling pathway, which modulates expression of several neurotransmitter receptors, also regulates dendritic development of cerebellar granule cells in the intact cerebellum. These results suggest that neuregulin-erbB signalling may control a program of postsynaptic development, from initiating dendrite morphogenesis to the formation and maturation of the postsynaptic apparatus.
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Affiliation(s)
- Heather I Rieff
- Neurobiology Program, Children's Hospital, Harvard Medical School, 300 Longwood Ave., Boston, MA 02115, USA
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91
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Yang P, Baker KA, Hagg T. The ADAMs family: coordinators of nervous system development, plasticity and repair. Prog Neurobiol 2006; 79:73-94. [PMID: 16824663 DOI: 10.1016/j.pneurobio.2006.05.001] [Citation(s) in RCA: 84] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2006] [Revised: 05/18/2006] [Accepted: 05/23/2006] [Indexed: 10/24/2022]
Abstract
A disintegrin and metalloprotease (ADAM) transmembrane proteins have metalloprotease, integrin-binding, intracellular signaling and cell adhesion activities. In contrast to other metalloproteases, ADAMs are particularly important for cleavage-dependent activation of proteins such as Notch, amyloid precursor protein (APP) and transforming growth factor alpha (TGFalpha), and can bind integrins. Not surprisingly, ADAMs have been shown or suggested to play important roles in the development of the nervous system, where they regulate proliferation, migration, differentiation and survival of various cells, as well as axonal growth and myelination. On the eleventh anniversary of the naming of this family of proteins, the relatively unknown ADAMs are emerging as potential therapeutic targets for neural repair. For example, over-expression of ADAM10, one of the alpha-secretases for APP, can prevent amyloid formation and hippocampal defects in an Alzheimer mouse model. Another example of this potential neural repair role is the finding that ADAM21 is uniquely associated with neurogenesis and growing axons of the adult brain. This comprehensive review will discuss the growing literature about the roles of ADAMs in the developing and adult nervous system, and their potential roles in neurological disorders. Most excitingly, the expanding understanding of their normal roles suggests that they can be manipulated to promote neural repair in the degenerating and injured adult nervous system.
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Affiliation(s)
- Peng Yang
- Kentucky Spinal Cord Injury Research Center, Department of Neurological Surgery, University of Louisville, Louisville, KY 40292, USA
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92
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Lu L, Neff F, Fischer DA, Henze C, Hirsch EC, Oertel WH, Schlegel J, Hartmann A. Regional vulnerability of mesencephalic dopaminergic neurons prone to degenerate in Parkinson's disease: a post-mortem study in human control subjects. Neurobiol Dis 2006; 23:409-21. [PMID: 16753304 DOI: 10.1016/j.nbd.2006.04.002] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2006] [Revised: 03/27/2006] [Accepted: 04/02/2006] [Indexed: 10/24/2022] Open
Abstract
Parkinson's disease (PD) is characterized by loss of dopaminergic (DA) neurons in the human midbrain, which varies greatly among mesencephalic subregions. The genetic expression profiles of mesencephalic DA neurons particularly prone to degenerate during PD (nigrosome 1 within the substantia nigra pars compacta-SNpc) and those particularly resistant in the disease course (central grey substance-CGS) were compared in five control subjects by immuno-laser capture microdissection followed by RNA arbitrarily primed PCR. 8 ESTs of interest were selected for analysis by real time quantitative reverse transcription PCR. DA neurons in the CGS preferentially expressed implicated in cell survival (7 out of 8 genes selected), whereas SNpc DA neurons preferentially expressed one gene making them potentially susceptible to undergo cell death in PD. We propose that factors making CGS DA neurons more resistant may be helpful in protecting SNpc DA neurons against a pathological insult.
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Affiliation(s)
- Lixia Lu
- Department of Neurology, Philipps-Universität Marburg, Germany
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93
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Bernstein HG, Lendeckel U, Bertram I, Bukowska A, Kanakis D, Dobrowolny H, Stauch R, Krell D, Mawrin C, Budinger E, Keilhoff G, Bogerts B. Localization of neuregulin-1α (heregulin-α) and one of its receptors, ErbB-4 tyrosine kinase, in developing and adult human brain. Brain Res Bull 2006; 69:546-59. [PMID: 16647583 DOI: 10.1016/j.brainresbull.2006.02.017] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2005] [Revised: 02/23/2006] [Accepted: 02/26/2006] [Indexed: 01/18/2023]
Abstract
Using immunohistochemistry, Western blot analysis, and RT-polymerase chain reaction, we studied the distribution of neuregulin-1 splice variant alpha (NRG-1alpha) and one of its putative receptors, ErbB-4 tyrosine kinase, in human brain. In the pre- and perinatal human brain immunoreactivity was confined to numerous neurons, with the highest cell density found in cortical gray matter, hypothalamus and cerebellum. In the adult brain, single cortical gray and white matter neurons showed NRG-1alpha immunoreactivity. Occasionally, immunoreactive oligodendrocytes were observed. NRG-1alpha-expressing neurons were also found in the hypothalamus, hippocampus, basal ganglia and brain stem. Application of two antibodies recognizing alpha and beta isoforms revealed a different distribution pattern in that many cortical and hippocampal pyramidal neurons were labeled. ErbB-4 immunoreactivity was expressed in both neurons and oligodendrocytes. Our data show that NRG-1alpha expression is lower in the adult human brain than in the developing brain, and, therefore, support a role for NRG-1alpha in brain development.
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94
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Kalkman HO. The role of the phosphatidylinositide 3-kinase–protein kinase B pathway in schizophrenia. Pharmacol Ther 2006; 110:117-34. [PMID: 16434104 DOI: 10.1016/j.pharmthera.2005.10.014] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2005] [Accepted: 10/26/2005] [Indexed: 01/05/2023]
Abstract
Neuroanatomical studies of brains from schizophrenic patients report evidence for neuronal dystrophy, while in genetic studies in schizophrenia there is evidence for mutations in growth factors and the downstream enzymes phosphatidylinositide 3-kinase (PI3K) and protein kinase B (PKB). Since the PI3K-PKB pathway is involved in cellular growth and proliferation, reduced activity of this cascade in schizophrenia could at least partly explain the neuronal dystrophy. Risk factors for schizophrenia, such as corticosteroids and cannabis, suppress the activity of the PI3K-PKB pathway. Conversely, estrogen and vitamin D, 2 factors with a moderate protective activity in schizophrenia, electroconvulsive shock therapy, and chronic treatment with antipsychotic compounds stimulate the pathway. Reduced activity of the PI3K-PKB pathway makes the brain more susceptible to virus infections, anoxia, and obstetric complications (recognized risk factors for schizophrenia), whereas a diminution of growth factor levels towards the end of puberty could contribute to an increase in schizophrenia symptoms observed around that time. On the other hand, constitutive (over)activation of the PI3K-PKB pathway increases cancer risk. Consequently, the presumed hypoactivity of the PI3K-PKB cascade might provide a partial explanation for the remarkable epidemiological finding of a reduced cancer rate in schizophrenic patients. Recognition of the role of a dysfunctional PI3K-PKB pathway in schizophrenia might help in the discovery of hitherto undetected causative gene mutations and could also lead to novel therapeutic approaches. However, a major challenge that remains to be solved is how the PI3K-PKB pathway can be activated without increasing the risk of cancer.
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Affiliation(s)
- Hans O Kalkman
- Neuroscience Research, Novartis Institutes of Biomedical Research Basel, Building WSJ-360.4.05, Novartis Pharma AG, CH4002 Basel, Switzerland.
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95
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Scolnick EM, Petryshen T, Sklar P. Schizophrenia: do the genetics and neurobiology of neuregulin provide a pathogenesis model? Harv Rev Psychiatry 2006; 14:64-77. [PMID: 16603473 DOI: 10.1080/10673220600642960] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
The sequencing of the human genome and an emerging dense map of markers across the human genome have spawned new approaches to search for risk genes for human diseases with complex genetics. These approaches are particularly relevant to the search for risk genes for bipolar disorder and schizophrenia. A gene called neuregulin 1 has been reported to be a risk gene for schizophrenia. This article reviews aspects of the genetics, cellular neurobiology, and biochemistry of neuregulin 1 and attempts to integrate several observations from disparate fields into a model for the pathogenesis of schizophrenia. The model outlines experimental approaches that may, in the future, shed more light on its validity.
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Affiliation(s)
- Edward M Scolnick
- Broad Institute of the Massachusetts Institute of Technology and Harvard University, Cambridge 02139, USA.
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96
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Chen J, Tseng HC, Dichter MA, Zhang H, Greene MI. Differential localization of ErbB receptor ensembles influences their signaling in hippocampal neurons. DNA Cell Biol 2006; 24:553-62. [PMID: 16153156 DOI: 10.1089/dna.2005.24.553] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Our studies indicate that ErbB complexes participate in both survival and synaptic plasticity signals of hippocampal neurons but in a manner that depends on the subcellular localization of the receptor ensembles. Using dissociated hippocampal cultures, we found that neurons, rather than glial cells, are the primary targets of ErbB receptor ligands such as epidermal growth factor and heregulin. Further investigation demonstrated that ErbB receptors distribute differentially in hippocampal neurons with the epidermal growth factor receptor confined to neural cell bodies and the p185(c-neu) and ErbB4 receptors distributed to both neural soma and neurites. Activation of ErbB receptor and downstream signaling molecules were observed in neurites only after heregulin stimulation. The receptor complex which mediated neurite located signals was the p185(c-neu)/ErbB4 heterodimer. Colocalization of p185(c-neu), but not epidermal growth factor receptor, with postsynaptic density protein 95 suggests that the heregulin signaling contributes to synapse specific activities. However, the epidermal growth factor receptor complex mediates physiological survival signals, as neuronal survival was enhanced by epidermal growth factor, rather than heregulin. Collectively, these studies indicate that different ErbB ensembles localize to different locations on the neuron to mediate distinct signals and functions.
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Affiliation(s)
- Jinqiu Chen
- Department of Pathology and Laboratory Medicine, University of Pennsylvania School of Medicine, Philadelphia, 19104, USA.
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97
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Sun MK, Alkon DL. Protein kinase C substrate activators: potential as novel antidepressants. Drug Dev Res 2005. [DOI: 10.1002/ddr.20019] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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