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Vullhorst D, Bloom MS, Akella N, Buonanno A. ER-PM Junctions on GABAergic Interneurons Are Organized by Neuregulin 2/VAP Interactions and Regulated by NMDA Receptors. Int J Mol Sci 2023; 24:2908. [PMID: 36769244 PMCID: PMC9917868 DOI: 10.3390/ijms24032908] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2023] [Revised: 01/24/2023] [Accepted: 01/27/2023] [Indexed: 02/05/2023] Open
Abstract
Neuregulins (NRGs) signal via ErbB receptors to regulate neural development, excitability, synaptic and network activity, and behaviors relevant to psychiatric disorders. Bidirectional signaling between NRG2/ErbB4 and NMDA receptors is thought to homeostatically regulate GABAergic interneurons in response to increased excitatory neurotransmission or elevated extracellular glutamate levels. Unprocessed proNRG2 forms discrete clusters on cell bodies and proximal dendrites that colocalize with the potassium channel Kv2.1 at specialized endoplasmic reticulum-plasma membrane (ER-PM) junctions, and NMDA receptor activation triggers rapid dissociation from ER-PM junctions and ectodomain shedding by ADAM10. Here, we elucidate the mechanistic basis of proNRG2 clustering at ER-PM junctions and its regulation by NMDA receptors. Importantly, we demonstrate that proNRG2 promotes the formation of ER-PM junctions by directly binding the ER-resident membrane tether VAP, like Kv2.1. The proNRG2 intracellular domain harbors two non-canonical, low-affinity sites that cooperatively mediate VAP binding. One of these is a cryptic and phosphorylation-dependent VAP binding motif that is dephosphorylated following NMDA receptor activation, thus revealing how excitatory neurotransmission promotes the dissociation of proNRG2 from ER-PM junctions. Therefore, proNRG2 and Kv2.1 can independently function as VAP-dependent organizers of neuronal ER-PM junctions. Based on these and prior studies, we propose that proNRG2 and Kv2.1 serve as co-regulated downstream effectors of NMDA receptors to homeostatically regulate GABAergic interneurons.
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Affiliation(s)
- Detlef Vullhorst
- Section on Molecular Neurobiology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, MD 20892, USA
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2
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Abstract
Reactive oxygen species (ROS) have emerged as regulators of key processes supporting neuronal growth, function, and plasticity across lifespan. At normal physiological levels, ROS perform important roles as secondary messengers in diverse molecular processes such as regulating neuronal differentiation, polarization, synapse maturation, and neurotransmission. In contrast, high levels of ROS are toxic and can ultimately lead to cell death. Excitable cells, such as neurons, often require high levels of metabolic activity to perform their functions. As a consequence, these cells are more likely to produce high levels of ROS, potentially enhancing their susceptibility to oxidative damage. In addition, because neurons are generally post-mitotic, they may be subject to accumulating oxidative damage. Thus, maintaining tight control over ROS concentration in the nervous system is essential for proper neuronal development and function. We are developing a more complete understanding of the cellular and molecular mechanisms for control of ROS in these processes. This review focuses on ROS regulation of the developmental and functional properties of neurons, highlighting recent in vivo studies. We also discuss the current evidence linking oxidative damage to pathological conditions associated with neurodevelopmental and neurodegenerative disorders.
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Expanding the Disorder-Function Paradigm in the C-Terminal Tails of Erbbs. Biomolecules 2021; 11:biom11111690. [PMID: 34827688 PMCID: PMC8615588 DOI: 10.3390/biom11111690] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2021] [Revised: 11/03/2021] [Accepted: 11/10/2021] [Indexed: 12/16/2022] Open
Abstract
ErbBs are receptor tyrosine kinases involved not only in development, but also in a wide variety of diseases, particularly cancer. Their extracellular, transmembrane, juxtamembrane, and kinase folded domains were described extensively over the past 20 years, structurally and functionally. However, their whole C-terminal tails (CTs) following the kinase domain were only described at atomic resolution in the last 4 years. They were shown to be intrinsically disordered. The CTs are known to be tyrosine-phosphorylated when the activated homo- or hetero-dimers of ErbBs are formed. Their phosphorylation triggers interaction with phosphotyrosine binding (PTB) or Src Homology 2 (SH2) domains and activates several signaling pathways controling cellular motility, proliferation, adhesion, and apoptosis. Beyond this passive role of phosphorylated domain and site display for partners, recent structural and function studies unveiled active roles in regulation of phosphorylation and interaction: the CT regulates activity of the kinase domain; different phosphorylation states have different compaction levels, potentially modulating the succession of phosphorylation events; and prolines have an important role in structure, dynamics, and possibly regulatory interactions. Here, we review both the canonical role of the disordered CT domains of ErbBs as phosphotyrosine display domains and the recent findings that expand the known range of their regulation functions linked to specific structural and dynamic features.
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4
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Ortiz MA, Mikhailova T, Li X, Porter BA, Bah A, Kotula L. Src family kinases, adaptor proteins and the actin cytoskeleton in epithelial-to-mesenchymal transition. Cell Commun Signal 2021; 19:67. [PMID: 34193161 PMCID: PMC8247114 DOI: 10.1186/s12964-021-00750-x] [Citation(s) in RCA: 48] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2021] [Accepted: 05/14/2021] [Indexed: 12/20/2022] Open
Abstract
Over a century of scientific inquiry since the discovery of v-SRC but still no final judgement on SRC function. However, a significant body of work has defined Src family kinases as key players in tumor progression, invasion and metastasis in human cancer. With the ever-growing evidence supporting the role of epithelial-mesenchymal transition (EMT) in invasion and metastasis, so does our understanding of the role SFKs play in mediating these processes. Here we describe some key mechanisms through which Src family kinases play critical role in epithelial homeostasis and how their function is essential for the propagation of invasive signals. Video abstract.
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Affiliation(s)
- Maria A Ortiz
- Department of Biochemistry and Molecular Biology, SUNY Upstate Medical University, Syracuse, USA.,Department of Urology, SUNY Upstate Medical University, Syracuse, USA
| | - Tatiana Mikhailova
- Department of Biochemistry and Molecular Biology, SUNY Upstate Medical University, Syracuse, USA
| | - Xiang Li
- Department of Biochemistry and Molecular Biology, SUNY Upstate Medical University, Syracuse, USA.,Department of Urology, SUNY Upstate Medical University, Syracuse, USA
| | - Baylee A Porter
- Department of Biochemistry and Molecular Biology, SUNY Upstate Medical University, Syracuse, USA.,Department of Urology, SUNY Upstate Medical University, Syracuse, USA
| | - Alaji Bah
- Department of Biochemistry and Molecular Biology, SUNY Upstate Medical University, Syracuse, USA
| | - Leszek Kotula
- Department of Biochemistry and Molecular Biology, SUNY Upstate Medical University, Syracuse, USA. .,Department of Urology, SUNY Upstate Medical University, Syracuse, USA.
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5
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Kiyatkin A, van Alderwerelt van Rosenburgh IK, Klein DE, Lemmon MA. Kinetics of receptor tyrosine kinase activation define ERK signaling dynamics. Sci Signal 2020; 13:13/645/eaaz5267. [PMID: 32817373 DOI: 10.1126/scisignal.aaz5267] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
In responses to activation of receptor tyrosine kinases (RTKs), crucial cell fate decisions depend on the duration and dynamics of ERK signaling. In PC12 cells, epidermal growth factor (EGF) induces transient ERK activation that leads to cell proliferation, whereas nerve growth factor (NGF) promotes sustained ERK activation and cell differentiation. These differences have typically been assumed to reflect distinct feedback mechanisms in the Raf-MEK-ERK signaling network, with the receptors themselves acting as simple upstream inputs. We failed to confirm the expected differences in feedback type when investigating transient versus sustained signaling downstream of the EGF receptor (EGFR) and NGF receptor (TrkA). Instead, we found that ERK signaling faithfully followed RTK dynamics when receptor signaling was modulated in different ways. EGFR activation kinetics, and consequently ERK signaling dynamics, were switched from transient to sustained when receptor internalization was inhibited with drugs or mutations, or when cells expressed a chimeric receptor likely to have impaired dimerization. In addition, EGFR and ERK signaling both became more sustained when substoichiometric levels of erlotinib were added to reduce duration of EGFR kinase activation. Our results argue that RTK activation kinetics play a crucial role in determining MAP kinase cascade signaling dynamics and cell fate decisions, and that signaling outcome can be modified by activating a given RTK in different ways.
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Affiliation(s)
- Anatoly Kiyatkin
- Department of Pharmacology, Yale University School of Medicine, New Haven, CT 06520, USA.,Cancer Biology Institute, Yale University, West Haven, CT 06516, USA
| | - Iris K van Alderwerelt van Rosenburgh
- Department of Pharmacology, Yale University School of Medicine, New Haven, CT 06520, USA.,Cancer Biology Institute, Yale University, West Haven, CT 06516, USA
| | - Daryl E Klein
- Department of Pharmacology, Yale University School of Medicine, New Haven, CT 06520, USA.,Cancer Biology Institute, Yale University, West Haven, CT 06516, USA
| | - Mark A Lemmon
- Department of Pharmacology, Yale University School of Medicine, New Haven, CT 06520, USA. .,Cancer Biology Institute, Yale University, West Haven, CT 06516, USA
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Neuregulins 1, 2, and 3 Promote Early Neurite Outgrowth in ErbB4-Expressing Cortical GABAergic Interneurons. Mol Neurobiol 2020; 57:3568-3588. [PMID: 32542595 DOI: 10.1007/s12035-020-01966-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2020] [Accepted: 05/29/2020] [Indexed: 12/27/2022]
Abstract
The neuregulins (Nrgs 1-4) are a family of signaling molecules that play diverse roles in the nervous system. Nrg1 has been implicated in the formation of synapses and in synaptic plasticity. Previous studies have shown Nrg1 can affect neurite outgrowth in several neuronal populations, while the role of Nrg2 and Nrg3 in this process has remained understudied. The Nrgs can bind and activate the ErbB4 receptor tyrosine kinase which is preferentially expressed in GABAergic interneurons in the rodent hippocampus and cerebral cortex. In the present study, we evaluated the effects of Nrgs 1, 2, and 3 on neurite outgrowth of dissociated rat cortical ErbB4-positive (+)/GABA+ interneurons in vitro. All three Nrgs were able to promote neurite outgrowth during the first 2 days in vitro, with increases detected for both the axon (116-120%) and other neurites (100-120%). Increases in the average number of primary and secondary neurites were also observed. Treatment with the Nrgs for an additional 3 days promoted an increase in axonal length (86-96%), with only minimal effects on the remaining neurites (8-13%). ErbB4 expression persisted throughout the dendritic arbor and cell soma at all stages examined, while its expression in the axon was transient and declined with cell maturation. ErbB4 overexpression in GABAergic neurons promoted neurite outgrowth, an effect that was potentiated by Nrg treatment. These results show that Nrgs 1, 2, and 3 are each capable of influencing dendritic and axonal growth at early developmental stages in GABAergic neurons grown in vitro.
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Xue WK, Zhao WJ, Meng XH, Shen HF, Huang PZ. Spinal cord injury induced Neuregulin 1 signaling changes in mouse prefrontal cortex and hippocampus. Brain Res Bull 2019; 144:180-186. [PMID: 30529367 DOI: 10.1016/j.brainresbull.2018.12.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2018] [Revised: 11/27/2018] [Accepted: 12/05/2018] [Indexed: 02/08/2023]
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Goldshmit Y, Tang JKKY, Siegel AL, Nguyen PD, Kaslin J, Currie PD, Jusuf PR. Different Fgfs have distinct roles in regulating neurogenesis after spinal cord injury in zebrafish. Neural Dev 2018; 13:24. [PMID: 30447699 PMCID: PMC6240426 DOI: 10.1186/s13064-018-0122-9] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2018] [Accepted: 11/08/2018] [Indexed: 11/10/2022] Open
Abstract
Background Despite conserved developmental processes and organization of the vertebrate central nervous system, only some vertebrates including zebrafish can efficiently regenerate neural damage including after spinal cord injury. The mammalian spinal cord shows very limited regeneration and neurogenesis, resulting in permanent life-long functional impairment. Therefore, there is an urgent need to identify the cellular and molecular mechanisms that can drive efficient vertebrate neurogenesis following injury. A key pathway implicated in zebrafish neurogenesis is fibroblast growth factor signaling. Methods In the present study we investigated the roles of distinct fibroblast growth factor members and their receptors in facilitating different aspects of neural development and regeneration at different timepoints following spinal cord injury. After spinal cord injury in adults and during larval development, loss and/or gain of Fgf signaling was combined with immunohistochemistry, in situ hybridization and transgenes marking motor neuron populations in in vivo zebrafish and in vitro mammalian PC12 cell culture models. Results Fgf3 drives neurogenesis of Islet1 expressing motor neuron subtypes and mediate axonogenesis in cMet expressing motor neuron subtypes. We also demonstrate that the role of Fgf members are not necessarily simple recapitulating development. During development Fgf2, Fgf3 and Fgf8 mediate neurogenesis of Islet1 expressing neurons and neuronal sprouting of both, Islet1 and cMet expressing motor neurons. Strikingly in mammalian PC12 cells, all three Fgfs increased cell proliferation, however, only Fgf2 and to some extent Fgf8, but not Fgf3 facilitated neurite outgrowth. Conclusions This study demonstrates differential Fgf member roles during neural development and adult regeneration, including in driving neural proliferation and neurite outgrowth of distinct spinal cord neuron populations, suggesting that factors including Fgf type, age of the organism, timing of expression, requirements for different neuronal populations could be tailored to best drive all of the required regenerative processes.
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Affiliation(s)
- Yona Goldshmit
- Australian Regenerative Medicine Institute, Monash University, Clayton, VIC, 3800, Australia.,Steyer School of Health Professions, Sackler School of Medicine, Tel-Aviv University, P.O. Box 39040, 6997801, Tel Aviv, Israel
| | - Jean Kitty K Y Tang
- Australian Regenerative Medicine Institute, Monash University, Clayton, VIC, 3800, Australia
| | - Ashley L Siegel
- Australian Regenerative Medicine Institute, Monash University, Clayton, VIC, 3800, Australia
| | - Phong D Nguyen
- Australian Regenerative Medicine Institute, Monash University, Clayton, VIC, 3800, Australia
| | - Jan Kaslin
- Australian Regenerative Medicine Institute, Monash University, Clayton, VIC, 3800, Australia
| | - Peter D Currie
- Australian Regenerative Medicine Institute, Monash University, Clayton, VIC, 3800, Australia
| | - Patricia R Jusuf
- Australian Regenerative Medicine Institute, Monash University, Clayton, VIC, 3800, Australia. .,School of Biosciences, University of Melbourne, Parkville, VIC, 3010, Australia.
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9
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Endesfelder S, Makki H, von Haefen C, Spies CD, Bührer C, Sifringer M. Neuroprotective effects of dexmedetomidine against hyperoxia-induced injury in the developing rat brain. PLoS One 2017; 12:e0171498. [PMID: 28158247 PMCID: PMC5291450 DOI: 10.1371/journal.pone.0171498] [Citation(s) in RCA: 54] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2016] [Accepted: 01/20/2017] [Indexed: 12/19/2022] Open
Abstract
Dexmedetomidine (DEX) is a highly selective agonist of α2-receptors with sedative, anxiolytic, and analgesic properties. Neuroprotective effects of dexmedetomidine have been reported in various brain injury models. In the present study, we investigated the effects of dexmedetomidine on hippocampal neurogenesis, specifically the proliferation capacity and maturation of neurons and neuronal plasticity following the induction of hyperoxia in neonatal rats. Six-day old sex-matched Wistar rats were exposed to 80% oxygen or room air for 24 h and treated with 1, 5 or 10 μg/kg of dexmedetomidine or normal saline. A single pretreatment with DEX attenuated the hyperoxia-induced injury in terms of neurogenesis and plasticity. In detail, both the proliferation capacity (PCNA+ cells) as well as the expression of neuronal markers (Nestin+, PSA-NCAM+, NeuN+ cells) and transcription factors (SOX2, Tbr1/2, Prox1) were significantly reduced under hyperoxia compared to control. Furthermore, regulators of neuronal plasticity (Nrp1, Nrg1, Syp, and Sema3a/f) were also drastically decreased. A single administration of dexmedetomidine prior to oxygen exposure resulted in a significant up-regulation of expression-profiles compared to hyperoxia. Our results suggest that dexmedetomidine may have neuroprotective effects in an acute hyperoxic model of the neonatal rat.
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Affiliation(s)
- Stefanie Endesfelder
- Department of Neonatology, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Hanan Makki
- Department of Neonatology, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Clarissa von Haefen
- Department of Anesthesiology and Intensive Care Medicine, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Claudia D Spies
- Department of Anesthesiology and Intensive Care Medicine, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Christoph Bührer
- Department of Neonatology, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Marco Sifringer
- Department of Anesthesiology and Intensive Care Medicine, Charité - Universitätsmedizin Berlin, Berlin, Germany
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10
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Vallières N, Barrette B, Wang LX, Bélanger E, Thiry L, Schneider MR, Filali M, Côté D, Bretzner F, Lacroix S. Betacellulin regulates schwann cell proliferation and myelin formation in the injured mouse peripheral nerve. Glia 2017; 65:657-669. [DOI: 10.1002/glia.23119] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2016] [Revised: 12/05/2016] [Accepted: 01/06/2017] [Indexed: 12/13/2022]
Affiliation(s)
- Nicolas Vallières
- Centre de recherche du Centre hospitalier universitaire (CHU) de Québec-CHUL et Département de médecine moléculaire; Faculté de médecine, Université Laval; Québec Canada
| | - Benoit Barrette
- Centre de recherche du Centre hospitalier universitaire (CHU) de Québec-CHUL et Département de médecine moléculaire; Faculté de médecine, Université Laval; Québec Canada
| | - Linda Xiang Wang
- Centre de recherche du Centre hospitalier universitaire (CHU) de Québec-CHUL et Département de médecine moléculaire; Faculté de médecine, Université Laval; Québec Canada
| | - Erik Bélanger
- Centre de recherche de l'Institut universitaire en santé mentale de Québec (CRIUSMQ) et Département de physique, génie physique et optique, Faculté des sciences et de génie, Université Laval; Québec Canada
- Centre d'optique, photonique et laser (COPL), Université Laval; Québec Canada
| | - Louise Thiry
- Centre de recherche du CHU de Québec-CHUL et Département de psychiatrie et de neurosciences de l'Université Laval; Faculté de Médecine, Université Laval; Québec Canada
| | - Marlon R. Schneider
- Institute of Molecular Animal Breeding and Biotechnology, Gene Center, LMU Munich; Munich Germany
| | - Mohammed Filali
- Centre de recherche du Centre hospitalier universitaire (CHU) de Québec-CHUL et Département de médecine moléculaire; Faculté de médecine, Université Laval; Québec Canada
| | - Daniel Côté
- Centre de recherche de l'Institut universitaire en santé mentale de Québec (CRIUSMQ) et Département de physique, génie physique et optique, Faculté des sciences et de génie, Université Laval; Québec Canada
- Centre d'optique, photonique et laser (COPL), Université Laval; Québec Canada
| | - Frédéric Bretzner
- Centre de recherche du CHU de Québec-CHUL et Département de psychiatrie et de neurosciences de l'Université Laval; Faculté de Médecine, Université Laval; Québec Canada
| | - Steve Lacroix
- Centre de recherche du Centre hospitalier universitaire (CHU) de Québec-CHUL et Département de médecine moléculaire; Faculté de médecine, Université Laval; Québec Canada
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11
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Jiang Q, Chen S, Hu C, Huang P, Shen H, Zhao W. Neuregulin-1 (Nrg1) signaling has a preventive role and is altered in the frontal cortex under the pathological conditions of Alzheimer's disease. Mol Med Rep 2016; 14:2614-24. [PMID: 27486021 PMCID: PMC4991731 DOI: 10.3892/mmr.2016.5542] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2016] [Accepted: 07/14/2016] [Indexed: 02/05/2023] Open
Abstract
Alzheimer's disease (AD), one of the neurodegenerative disorders that may develop in the elderly, is characterized by the deposition of β‑amyloid protein (Aβ) and extensive neuronal cell death in the brain. Neuregulin‑1 (Nrg1)‑mediated intercellular and intracellular communication via binding to ErbB receptors regulates a diverse set of biological processes involved in the development of the nervous system. In the present study, a linear correlation was identified between Nrg1 and phosphorylated ErbB (pNeu and pErbB4) receptors in a human cortical tissue microarray. In addition, increased expression levels of Nrg1, but reduced pErbB receptor levels, were detected in the frontal lobe of a patient with AD. Western blotting and immunofluorescence staining were subsequently performed to uncover the potential preventive role of Nrg1 in cortical neurons affected by the neurodegenerative processes of AD. It was observed that the expression of Nrg1 increased as the culture time of the cortical neurons progressed. In addition, H2O2 and Aβ1‑42, two inducers of oxidative stress and neuronal damage, led to a dose‑dependent decrease in Nrg1 expression. Recombinant Nrg1β, however, was revealed to exert a pivotal role in preventing oxidative stress and neuronal damage from occurring in the mouse cortical neurons. Taken together, these results suggest that changes in Nrg1 signaling may influence the pathological development of AD, and exogenous Nrg1 may serve as a potential candidate for the prevention and treatment of AD.
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Affiliation(s)
| | | | | | | | | | - Weijiang Zhao
- Correspondence to: Professor Weijiang Zhao, Center for Neuroscience, Shantou University Medical College, 22 Xinling Road, Shantou, Guangdong 515041, P.R. China, E-mail:
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12
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YANG ZHAI, JIANG QIONG, CHEN SHUANGXI, HU CHENGLIANG, SHEN HUIFAN, HUANG PEIZHI, XU JUNPING, MEI JINPING, ZHANG BENPING, ZHAO WEIJIANG. Differential changes in Neuregulin-1 signaling in major brain regions in a lipopolysaccharide-induced neuroinflammation mouse model. Mol Med Rep 2016; 14:790-6. [PMID: 27220549 PMCID: PMC4918623 DOI: 10.3892/mmr.2016.5325] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2015] [Accepted: 05/10/2016] [Indexed: 02/05/2023] Open
Abstract
Neuregulin 1 (Nrg1) is involved in multiple biological processes in the nervous system. The present study investigated changes in Nrg1 signaling in the major brain regions of mice subjected to lipopolysaccharide (LPS)-induced neuroinflammation. At 24 h post‑intraperitoneal injection of LPS, mouse brain tissues, including tissues from the cortex, striatum, hippocampus and hypothalamus, were collected. Reverse transcription‑polymerase chain reaction was used to determine the expression of Nrg1 and its receptors, Neu and ErbB4, at the mRNA level. Western blotting was performed to determine the levels of these proteins and the protein levels of phosphorylated extracellular signal-regulated kinases (Erk)1/2 and Akt1. Immunohistochemical staining was utilized to detect the levels of pNeu and pErbB4 in these regions. LPS successfully induced sites of neuroinflammation in these regions, in which changes in Nrg1, Neu and ErbB4 at the mRNA and protein levels were identified compared with controls. LPS induced a reduction in pNeu and pErbB4 in the striatum and hypothalamus, although marginally increased pErbB4 levels were found in the hippocampus. LPS increased the overall phosphorylation of Src but this effect was reduced in the hypothalamus. Moreover, increased phosphorylation of Akt1 was found in the striatum and hippocampus. These data suggest diverse roles for Nrg1 signaling in these regions during the process of neuroinflammation.
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Affiliation(s)
- ZHAI YANG
- Center for Neuroscience, Shantou University Medical College, Shantou, Guangdong 515041, P.R. China
| | - QIONG JIANG
- Center for Neuroscience, Shantou University Medical College, Shantou, Guangdong 515041, P.R. China
| | - SHUANG-XI CHEN
- Center for Neuroscience, Shantou University Medical College, Shantou, Guangdong 515041, P.R. China
| | - CHENG-LIANG HU
- Center for Neuroscience, Shantou University Medical College, Shantou, Guangdong 515041, P.R. China
| | - HUI-FAN SHEN
- Center for Neuroscience, Shantou University Medical College, Shantou, Guangdong 515041, P.R. China
| | - PEI-ZHI HUANG
- Center for Neuroscience, Shantou University Medical College, Shantou, Guangdong 515041, P.R. China
| | - JUN-PING XU
- Center for Neuroscience, Shantou University Medical College, Shantou, Guangdong 515041, P.R. China
| | - JIN-PING MEI
- Graduate School, Tianjin University of Traditional Chinese Medicine, Tianjin 300193, P.R. China
| | - BEN-PING ZHANG
- Department of Neurology, The 2nd Affiliated Hospital, Harbin Medical University, Harbin, Heilongjiang 150086, P.R. China
| | - WEI-JIANG ZHAO
- Center for Neuroscience, Shantou University Medical College, Shantou, Guangdong 515041, P.R. China
- Correspondence to: Dr Wei-Jiang Zhao, Center for Neuroscience, Shantou University Medical College, 22 Xinling Road, Shantou, Guangdong 515041, P.R. China, E-mail:
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13
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Impairments in dendrite morphogenesis as etiology for neurodevelopmental disorders and implications for therapeutic treatments. Neurosci Biobehav Rev 2016; 68:946-978. [PMID: 27143622 DOI: 10.1016/j.neubiorev.2016.04.008] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2015] [Revised: 04/13/2016] [Accepted: 04/13/2016] [Indexed: 02/08/2023]
Abstract
Dendrite morphology is pivotal for neural circuitry functioning. While the causative relationship between small-scale dendrite morphological abnormalities (shape, density of dendritic spines) and neurodevelopmental disorders is well established, such relationship remains elusive for larger-scale dendrite morphological impairments (size, shape, branching pattern of dendritic trees). Here, we summarize published data on dendrite morphological irregularities in human patients and animal models for neurodevelopmental disorders, with focus on autism and schizophrenia. We next discuss high-risk genes for these disorders and their role in dendrite morphogenesis. We finally overview recent developments in therapeutic attempts and we discuss how they relate to dendrite morphology. We find that both autism and schizophrenia are accompanied by dendritic arbor morphological irregularities, and that majority of their high-risk genes regulate dendrite morphogenesis. Thus, we present a compelling argument that, along with smaller-scale morphological impairments in dendrites (spines and synapse), irregularities in larger-scale dendrite morphology (arbor shape, size) may be an important part of neurodevelopmental disorders' etiology. We suggest that this should not be ignored when developing future therapeutic treatments.
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14
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Merelo V, Durand D, Lescallette AR, Vrana KE, Hong LE, Faghihi MA, Bellon A. Associating schizophrenia, long non-coding RNAs and neurostructural dynamics. Front Mol Neurosci 2015; 8:57. [PMID: 26483630 PMCID: PMC4588008 DOI: 10.3389/fnmol.2015.00057] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2015] [Accepted: 09/10/2015] [Indexed: 01/10/2023] Open
Abstract
Several lines of evidence indicate that schizophrenia has a strong genetic component. But the exact nature and functional role of this genetic component in the pathophysiology of this mental illness remains a mystery. Long non-coding RNAs (lncRNAs) are a recently discovered family of molecules that regulate gene transcription through a variety of means. Consequently, lncRNAs could help us bring together apparent unrelated findings in schizophrenia; namely, genomic deficiencies on one side and neuroimaging, as well as postmortem results on the other. In fact, the most consistent finding in schizophrenia is decreased brain size together with enlarged ventricles. This anomaly appears to originate from shorter and less ramified dendrites and axons. But a decrease in neuronal arborizations cannot explain the complex pathophysiology of this psychotic disorder; however, dynamic changes in neuronal structure present throughout life could. It is well recognized that the structure of developing neurons is extremely plastic. This structural plasticity was thought to stop with brain development. However, breakthrough discoveries have shown that neuronal structure retains some degree of plasticity throughout life. What the neuroscientific field is still trying to understand is how these dynamic changes are regulated and lncRNAs represent promising candidates to fill this knowledge gap. Here, we present evidence that associates specific lncRNAs with schizophrenia. We then discuss the potential role of lncRNAs in neurostructural dynamics. Finally, we explain how dynamic neurostructural modifications present throughout life could, in theory, reconcile apparent unrelated findings in schizophrenia.
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Affiliation(s)
- Veronica Merelo
- Department of Psychiatry and Behavioral Sciences, University of Miami, Miller School of Medicine Miami, FL, USA
| | - Dante Durand
- Department of Psychiatry and Behavioral Sciences, University of Miami, Miller School of Medicine Miami, FL, USA
| | - Adam R Lescallette
- Penn State Hershey Medical Center, Department of Pharmacology Hershey, PA, USA ; Penn State Hershey Medical Center, Department of Psychiatry Hershey, PA, USA
| | - Kent E Vrana
- Penn State Hershey Medical Center, Department of Pharmacology Hershey, PA, USA
| | - L Elliot Hong
- Maryland Psychiatric Research Center, Department of Psychiatry, University of Maryland School of Medicine Baltimore, MD, USA
| | - Mohammad Ali Faghihi
- Center for Therapeutic Innovation, Department of Psychiatry and Behavioral Sciences University of Miami, Miller School of Medicine Miami, FL, USA
| | - Alfredo Bellon
- Penn State Hershey Medical Center, Department of Pharmacology Hershey, PA, USA ; Penn State Hershey Medical Center, Department of Psychiatry Hershey, PA, USA
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Developmental pathways hijacked by osteosarcoma. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2014; 804:93-118. [PMID: 24924170 DOI: 10.1007/978-3-319-04843-7_5] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Cancer of any type often can be described by an arrest, alteration or disruption in the normal development of a tissue or organ, and understanding of the normal counterpart's development can aid in understanding the malignant state. This is certainly true for osteosarcoma and the normal developmental pathways that guide osteoblast development that are changed in the genesis of osteogenic sarcoma. A carefully regulated crescendo-decrescendo expression of RUNX2 accompanies the transition from mesenchymal stem cell to immature osteoblast to mature osteoblast. This pivotal role is controlled by several pathways, including bone morphogenic protein (BMP), Wnt/β-catenin, fibroblast growth factor (FGF), and protein kinase C (PKC). The HIPPO pathway and its downstream target YAP help to regulate proliferation of immature osteoblasts and their maturation into non-proliferating mature osteoblasts. This pathway also helps regulate expression of the mature osteoblast protein osteocalcin. YAP also regulates expression of MT1-MMP, a membrane-bound matrix metalloprotease responsible for remodeling the extracellular matrix surrounding the osteoblasts. YAP, in turn, can be regulated by the ERBB family protein Her-4. Osteosarcoma may be thought of as a cell held at the immature osteoblast stage, retaining some of the characteristics of that developmental stage. Disruptions of several of these pathways have been described in osteosarcoma, including BMP, Wnt/b-catenin, RUNX2, HIPPO/YAP, and Her-4. Further, PKC can be activated by several receptor tyrosine kinases implicated in osteosarcoma, including the ERBB family (EGFR, Her-2 and Her-4 in osteosarcoma), IGF1R, FGF, and others. Understanding these functions may aid in the understanding the mechanisms underpinning clinical observations in osteosarcoma, including both the lytic and blastic phenotypes of tumors, the invasiveness of the disease, and the tendency for treated tumors to ossify rather than shrink. Through a better understanding of the relationship between normal osteoblast development and osteosarcoma, we may gain insights into novel therapeutic avenues and improved outcomes.
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García L, Castillo C, Carballo J, Rodríguez Y, Forsyth P, Medina R, Martínez JC, Longart M. ErbB receptors and PKC regulate PC12 neuronal-like differentiation and sodium current elicitation. Neuroscience 2013; 236:88-98. [PMID: 23380500 DOI: 10.1016/j.neuroscience.2013.01.026] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2012] [Revised: 01/09/2013] [Accepted: 01/10/2013] [Indexed: 10/27/2022]
Abstract
Excitability, neurite outgrowth and their specification are very important features in the establishment of neuronal differentiation. We have studied a conditioned medium (CM) from sciatic nerve which is able to induce a neuronal-like differentiation of PC12 cells. Previously, we have demonstrated that supplementing this CM with a generic inhibitor (k252a), which mainly inhibits tropomyosin-related kinase receptors (Trk receptors) and protein kinase C (PKC), caused neurite elongation, sodium current induction and axon development. In the present work, we are showing that the enhancement of neurite length and induction of sodium currents induced by CM+k252a were prevented by ErbB receptor inhibition. Additionally, we demonstrated that specific inhibition of PKC produced a similar effect to that exerted by k252a in CM-treated cells, specifically by increasing the percentage of differentiated cells with long neurites and inducing sodium currents. Moreover, CM changed the mRNA levels for ErbB2 and ErbB3 increasing them 6- and 36-folds respectively compared to their control. The inclusion of k252a with CM changed the ErbB1, ErbB2 and ErbB3 mRNA proportions increasing those eight-, seven- and fivefolds respectively. From this point, it is clear that appropriate ErbB receptor levels and PKC inhibition are necessary to enhance the effect of the CM in inducing the neuronal-like differentiation of PC12 cells. In summary, we demonstrated the involvement of ErbB receptors in the regulation of neurite elongation and sodium current induction in PC12 cells and propose that these processes could be initiated by ErbB receptors followed by a fine regulation of PKC signaling. These findings might implicate a novel interplay between ErbB receptors and PKC in the regulation of these molecular mechanisms.
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Affiliation(s)
- L García
- Unidad de Neurociencias, Instituto de Estudios Avanzados (IDEA), Caracas 1015A, Venezuela
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17
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A brain aggregate model gives new insights into the pathobiology and treatment of prion diseases. J Neuropathol Exp Neurol 2012; 71:449-66. [PMID: 22507918 DOI: 10.1097/nen.0b013e3182544680] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Brain aggregates (BrnAggs) derived from fetal mouse brains contain mature neurons and glial cells. We determined that BrnAggs are consistently infected with Rocky Mountain Laboratory scrapie strain prions and produce increasing levels of the pathogenic form of the prion protein (PrP). Their abundant dendrites undergo degeneration shortly after prion infection. Treatment of prion-infected BrnAggs with drugs, such as a γ-secretase inhibitors and quinacrine (Qa), which stop PrP formation and dendritic degeneration, mirrors the results from rodent studies. Because PrP is trafficked into lysosomes by endocytosis and autophagosomes by phagocytosis in neurons of prion strain-infected BrnAggs, we studied the effects of drugs that modulate subcellular trafficking. Rapamycin (Rap), which activates autophagy, markedly increased light-chain 3-II (LC3-II)-positive autophagosomes and cathepsin D-positive lysosomes in BrnAggs but could not eliminate the intracellular PrP within them. Adding Qa to Rap markedly reduced the number of LC3-II-positive autolysosomes. Rap + Qa created a competition between Rap increasing and Qa decreasing LC3-II. Rapamycin + Qa decreased total PrP by 56% compared with that of Qa alone, which reduced PrP by 37% relative to Rap alone. We conclude that the decrease was dominated by the ability of Qa to decrease the formation of PrP. Therefore, BrnAggs provide an efficient in vitro tool for screening drug therapies and studying the complex biology of prions.
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Tomokiyo A, Maeda H, Fujii S, Monnouchi S, Wada N, Kono K, Yamamoto N, Koori K, Teramatsu Y, Akamine A. A multipotent clonal human periodontal ligament cell line with neural crest cell phenotypes promotes neurocytic differentiation, migration, and survival. J Cell Physiol 2012; 227:2040-50. [PMID: 21751215 DOI: 10.1002/jcp.22933] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Repair of injured peripheral nerve is thought to play important roles in tissue homeostasis and regeneration. Recent experiments have demonstrated enhanced functional recovery of damaged neurons by some types of somatic stem cells. It remains unclear, however, if periodontal ligament (PDL) stem cells possess such functions. We recently developed a multipotent clonal human PDL cell line, termed cell line 1-17. Here, we investigated the effects of this cell line on neurocytic differentiation, migration, and survival. This cell line expressed the neural crest cell marker genes Slug, SOX10, Nestin, p75NTR, and CD49d and mesenchymal stem cell-related markers CD13, CD29, CD44, CD71, CD90, CD105, and CD166. Rat adrenal pheochromocytoma cells (PC12 cells) underwent neurocytic differentiation when co-cultured with cell line 1-17 or in conditioned medium from cell line 1-17 (1-17CM). ELISA analysis revealed that 1-17CM contained approximately 50 pg/ml nerve growth factor (NGF). Cell line 1-17-induced migration of PC12 cells, which was inhibited by a neutralizing antibody against NGF. Furthermore, 1-17CM exerted antiapoptotic effects on differentiated PC12 cells as evidenced by inhibition of neurite retraction, reduction in annexin V and caspase-3/7 staining, and induction of Bcl-2 and Bcl-xL mRNA expression. Thus, cell line 1-17 promoted neurocytic differentiation, migration, and survival through secretion of NGF and possibly synergistic factors. PDL stem cells may play a role in peripheral nerve reinnervation during PDL regeneration.
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Affiliation(s)
- Atsushi Tomokiyo
- Faculty of Dental Science, Division of Oral Rehabilitation, Department of Endodontology and Operative Dentistry, Kyushu University, Fukuoka, Japan
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Karlsgodt KH, Bachman P, Winkler AM, Bearden CE, Glahn DC. Genetic influence on the working memory circuitry: behavior, structure, function and extensions to illness. Behav Brain Res 2011; 225:610-22. [PMID: 21878355 DOI: 10.1016/j.bbr.2011.08.016] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2011] [Accepted: 08/07/2011] [Indexed: 10/17/2022]
Abstract
Working memory is a highly heritable complex cognitive trait that is critical for a number of higher-level functions. However, the neural substrates of this behavioral phenotype are intricate and it is unknown through what precise biological mechanism variation in working memory is transmitted. In this review we explore different functional and structural components of the working memory circuitry, and the degree to which each of them is contributed to by genetic factors. Specifically, we consider dopaminergic function, glutamatergic function, white matter integrity and gray matter structure all of which provide potential mechanisms for the inheritance of working memory deficits. In addition to discussing the overall heritability of these measures we also address specific genes that may play a role. Each of these heritable components has the potential to uniquely contribute to the working memory deficits observed in genetic disorders, including 22q deletion syndrome, fragile X syndrome, phenylketonuria (PKU), and schizophrenia. By observing the individual contributions of disruptions in different components of the working memory circuitry to behavioral performance, we highlight the concept that there may be many routes to a working memory deficit; even though the same cognitive measure may be a valid endophenotype across different disorders, the underlying cause of, and treatment for, the deficit may differ. This has implications for our understanding of the transmission of working memory deficits in both healthy and disordered populations.
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Affiliation(s)
- Katherine H Karlsgodt
- Department of Psychiatry and Biobehavioral Sciences, Semel Institute for Neuroscience and Human Behavior, University of California Los Angeles, Los Angeles, CA, USA.
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20
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Marques F, Sousa JC, Coppola G, Gao F, Puga R, Brentani H, Geschwind DH, Sousa N, Correia-Neves M, Palha JA. Transcriptome signature of the adult mouse choroid plexus. Fluids Barriers CNS 2011; 8:10. [PMID: 21349147 PMCID: PMC3042978 DOI: 10.1186/2045-8118-8-10] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2010] [Accepted: 01/18/2011] [Indexed: 12/31/2022] Open
Abstract
Background Although the gene expression profile of several tissues in humans and in rodent animal models has been explored, analysis of the complete choroid plexus (CP) transcriptome is still lacking. A better characterization of the CP transcriptome can provide key insights into its functions as one of the barriers that separate the brain from the periphery and in the production of cerebrospinal fluid. Methods This work extends further what is known about the mouse CP transcriptome through a microarray analysis of CP tissue from normal mice under physiological conditions. Results We found that the genes most highly expressed are those implicated in energy metabolism (oxidative phosphorylation, glycolysis/gluconeogenesis) and in ribosomal function, which is in agreement with the secretory nature of the CP. On the other hand, genes encoding for immune mediators are among those with lower expression in basal conditions. In addition, we found genes known to be relevant during brain development, and not previously identified to be expressed in the CP, including those encoding for various axonal guidance and angiogenesis molecules and for growth factors. Some of these are known to influence the neural stem cell niche in the subventricular zone, highlighting the involvement of the CP as a likely modulator of neurogenesis. Interestingly, our observations confirm that the CP transcriptome is unique, displaying low homology with that of other tissues. Of note, we describe here that the closest similarity is with the transcriptome of the endothelial cells of the blood-brain barrier. Conclusions Based on the data presented here, it will now be possible to further explore the function of particular proteins of the CP secretome in health and in disease.
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Affiliation(s)
- Fernanda Marques
- Life and Health Sciences Research Institute (ICVS), School of Health Sciences, University of Minho, Campus Gualtar, 4710-057 Braga, Portugal.
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Guo WP, Fu XG, Jiang SM, Wu JZ. Neuregulin-1 regulates the expression of Akt, Bcl-2, and Bad signaling after focal cerebral ischemia in rats. Biochem Cell Biol 2010; 88:649-54. [PMID: 20651836 DOI: 10.1139/o09-189] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Neuregulin-1 (NRG-1) is a member of the epidermal growth factor family. Our previous study showed that NRG-1 protected neurons from apoptosis following focal cerebral ischemia by the inhibition of caspase-3 and TNF-alpha expression. However, the molecular signaling mechanisms for this action of NRG-1 following cerebral ischemia are not fully understood. Presently, activation of the PI3K/Akt pathway has been implicated as a major contributor to neuronal survival after an ischemic insult. In the present study, we investigated whether NRG-1 modulates the activation of Akt and its downstream targets Bad and Bcl-2 expression after transient focal cerebral ischemia by intraluminal blockade of the middle cerebral artery. Western blot was employed to analyze the change of phosphorylated Akt (p-Akt) expression; reverse transcription and polymerization chain reaction (RT-PCR) were used to measure changes of Bcl-2 mRNA. The level of phosphorylation of Bad (p-Bad) was determined using an enzyme-linked immunosorbent assay (ELISA). Our results showed that recombinant human NRG-1(3.0 ng.kg-1) significantly increased the expression of p-Akt protein, Bcl-2 mRNA, and the level of p-Bad, respectively, whereas administration of LY294002, a specific inhibitor of PI3K, significantly decreased the expression of p-Akt, p-Bad, and Bcl-2 induced by NRG-1 after a 60 min ischemic insult, followed by 24 h of reperfusion. These results indicate that NRG-1 may be involved in regulating the expression of Bcl-2 and p-Bad through the PI3K/Akt pathway after transient focal cerebral ischemia.
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Affiliation(s)
- Wen-Ping Guo
- Department of Anatomy, Medical College of Shantou University, Shantou, Guangdong, China.
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22
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Frey MR, Hilliard VC, Mullane MT, Polk DB. ErbB4 promotes cyclooxygenase-2 expression and cell survival in colon epithelial cells. J Transl Med 2010; 90:1415-24. [PMID: 20585313 PMCID: PMC2947587 DOI: 10.1038/labinvest.2010.117] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
The ErbB4 receptor tyrosine kinase is expressed at high levels in human and mouse colitis, and inhibits colon epithelial cell apoptosis in the presence of proinflammatory cytokines. In this study, we investigated the molecular mechanisms responsible for ErbB4-induced cell survival. In cultured mouse colon epithelial cells, ErbB4 overexpression resulted in increased levels of cyclooxygenase-2 (COX-2) mRNA and protein; in contrast, ErbB4 knockdown with siRNA blocked COX-2 accumulation in response to tumor necrosis factor. Although ErbB4 is expressed as up to four isoforms in epithelial tissues, its ability to promote COX-2 expression was isoform independent. ErbB4-stimulated COX-2 induction was associated with an increase in mRNA half-life and was blocked by inhibition of Src, phosphatidylinositol (PI) 3-kinase, or epidermal growth factor receptor (EGFR). Furthermore, ErbB4 expression promoted EGFR phosphorylation in the presence of heregulin, implicating ErbB4-EGFR heterodimerization in these responses. As to the cellular responses to ErbB4 activation, increased survival of ErbB4-expressing cells in the presence of proinflammatory cytokines was sensitive to the COX-2 inhibitor celecoxib. Furthermore, ErbB4-overexpressing cells acquired the ability to form colonies in soft agar, indicative of cellular transformation, also in a celecoxib-sensitive manner. Together our data indicate that ErbB4 is a key regulator of COX-2 expression and cellular survival in colon epithelial cells, acting in concert with EGFR through a Src- and PI 3-kinase-dependent mechanism. These results suggest that chronic overexpression of ErbB4 in the context of inflammation could contribute to colitis-associated tumorigenesis by inhibiting colonocyte apoptosis.
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Affiliation(s)
- Mark Ronald Frey
- Department of Pediatrics, Division of Gastroenterology, Hepatology & Nutrition, Vanderbilt University School of Medicine, Nashville, TN 37232
| | - Valda Catherine Hilliard
- Department of Cell & Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37232
| | - Matthew Travis Mullane
- Department of Pediatrics, Division of Gastroenterology, Hepatology & Nutrition, Vanderbilt University School of Medicine, Nashville, TN 37232
| | - D. Brent Polk
- Department of Pediatrics, Division of Gastroenterology, Hepatology & Nutrition, Vanderbilt University School of Medicine, Nashville, TN 37232, Department of Cell & Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37232
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Zhou Y, Besner GE. Heparin-binding epidermal growth factor-like growth factor is a potent neurotrophic factor for PC12 cells. Neurosignals 2010; 18:141-51. [PMID: 20847549 DOI: 10.1159/000319823] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2010] [Accepted: 07/30/2010] [Indexed: 01/04/2023] Open
Abstract
Heparin-binding epidermal growth factor EGF-like growth factor (HB-EGF) is a member of the epidermal growth factor family that is expressed in many cell types. We have previously reported the effects of HB-EGF on intestinal epithelial cells and endothelial cells after exposure to ischemia/reperfusion in vivo or anoxia/reoxygenation injury in vitro. However, the effect of HB-EGF on neuronal cells is largely unexplored. In this study, we examined the effect of HB-EGF on neurite outgrowth in pheochromocytoma (PC12) cells as well as the neuroprotective effect of HB-EGF on injured PC12 cells exposed to oxygen and glucose deprivation (OGD), which mimics ischemic conditions. We found that HB-EGF significantly promotes PC12 cell neurite outgrowth and that this effect was blocked by EGF receptor (EGFR) inhibition or mitogen-activated protein kinase (MAPK) inhibition, but not by tyrosine kinase inhibition. In the face of OGD injury, HB-EGF preserves cell viability and decreases apoptosis and LDH release in PC12 cells. HB-EGF-mediated cytoprotection was abolished by EGFR inhibition and MAPK inhibition. We conclude that HB-EGF, through its interaction with the EGF receptor, activates the MAPK signaling pathway in PC12 cells under basal or injury conditions, leading to enhanced neurite outgrowth and neuroprotection against ischemic injury.
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Affiliation(s)
- Yu Zhou
- Department of Pediatric Surgery, Research Institute at Nationwide Children's Hospital, Center for Perinatal Research, Nationwide Children's Hospital, Ohio State University College of Medicine, Columbus, Ohio, USA
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24
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Geng L, Li Q. Expression and function of heregulin-alpha and its receptors in the mouse mammary gland. SCIENCE CHINA-LIFE SCIENCES 2010; 53:1015-24. [PMID: 20821301 DOI: 10.1007/s11427-010-4042-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2009] [Accepted: 05/26/2010] [Indexed: 11/26/2022]
Abstract
Heregulin-alpha (HRGalpha) is a cytokine secreted by the mammary mesenchyme, adjacent to lobuloalveolar structures. To understand the role of HRGalpha and its receptors in mammary glands, and the underlying mechanisms, we performed this study to determine the expression and localization of HRGalpha and its receptors ErbB2 and ErbB3. We also determined the role of HRGalpha in the development of mammary glands, beta-casein expression and secretion, Rab3A protein expression and the phosphorylation of HRGalpha signaling molecules using confocal laser scanning microscopy, tissue culture, capillary electrophoresis, Western blotting and enzyme-linked immunosorbent assays. We found that a peak was on pregnancy day 15. Changes of ErbB2 and ErbB3 expression were positively and linearly correlated with HRGalpha, indicating that HRGalpha positively regulates ErbB2 and ErbB3 expression. During pregnancy, HRGalpha enhanced the phosphorylation of STAT5, p42/p44, p38, PKC and Rab3A protein expression, stimulated the proliferation and differentiation of the ductal epithelial cells of mammary glands, and increased and maintained the expression and secretion of beta-casein. During lactation, HRGalpha enhanced the phosphorylation of STAT5 and p38, inhibited the phosphorylation of PKC and Rab3A protein expression, maintained the morphology of the mammary glands and increased the secretion of lactoprotein to reduce the expression of beta-casein in mammary epithelial cells. During involution, HRGalpha induced the phosphorylation of STAT3 and Rab3A protein expression, and inhibited the phosphorylation of PKC to stimulate the degeneration of mammary epithelial cells. It also inhibited the secretion of beta-casein, resulting in increased levels of beta-casein in mammary epithelial cells.
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Affiliation(s)
- LiJing Geng
- Institute of Food Science and Engineering, Liaoning Medical University, Jinzhou, China
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25
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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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Dearmond SJ, Bajsarowicz K. PrPSc accumulation in neuronal plasma membranes links Notch-1 activation to dendritic degeneration in prion diseases. Mol Neurodegener 2010; 5:6. [PMID: 20205843 PMCID: PMC2825502 DOI: 10.1186/1750-1326-5-6] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2009] [Accepted: 01/21/2010] [Indexed: 11/25/2022] Open
Abstract
Prion diseases are disorders of protein conformation in which PrPC, the normal cellular conformer, is converted to an abnormal, protease-resistant conformer rPrPSc. Approximately 80% of rPrPSc accumulates in neuronal plasma membranes where it changes their physical properties and profoundly affects membrane functions. In this review we explain how rPrPSc is transported along axons to presynaptic boutons and how we envision the conversion of PrPC to rPrPSc in the postsynaptic membrane. This information is a prerequisite to the second half of this review in which we present evidence that rPrPSc accumulation in synaptic regions links Notch-1 signaling with the dendritic degeneration. The hypothesis that the Notch-1 intracellular domain, NICD, is involved in prion disease was tested by treating prion-infected mice with the γ-secretase inhibitor (GSI) LY411575, with quinacrine (Qa), and with the combination of GSI + Qa. Surprisingly, treatment with GSI alone markedly decreased NICD but did not prevent dendritic degeneration. Qa alone produced near normal dendritic trees. The combined GSI + Qa treatment resulted in a richer dendritic tree than in controls. We speculate that treatment with GSI alone inhibited both stimulators and inhibitors of dendritic growth. With the combined GSI + Qa treatment, Qa modulated the effect of GSI perhaps by destabilizing membrane rafts. GSI + Qa decreased PrPSc in the neocortex and the hippocampus by 95%, but only by 50% in the thalamus where disease was begun by intrathalamic inoculation of prions. The results of this study indicate that GSI + Qa work synergistically to prevent dendrite degeneration and to block formation of PrPSc.
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Affiliation(s)
- Stephen J Dearmond
- Department of Pathology, University of California San Francisco, 1855 Folsom Street MCB 269, San Francisco, CA 94143-0803, USA.
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27
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Integrated analysis of receptor activation and downstream signaling with EXTassays. Nat Methods 2009; 7:74-80. [PMID: 20010833 DOI: 10.1038/nmeth.1407] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2009] [Accepted: 11/12/2009] [Indexed: 12/25/2022]
Abstract
The ability to measure multiple cellular signaling events is essential to better understand the underlying complex biological processes that occur in living cells. Microarray-based technologies are now commonly used to study changes in transcription. This information, however, is not sufficient to understand the regulatory mechanisms that lead to gene expression changes. Here we present an approach to monitor signaling events upstream of gene expression. We coupled different reporter gene assays to unique expressed oligonucleotide tags (EXTs) that serve as identifiers and quantitative reporters. Multiple EXT reporters can be isolated as a pool and analyzed by hybridization to microarrays. To test the feasibility of our approach, we integrated complementation assays based on a protease from tobacco etch virus (TEV protease) and transcription factor activity profiling. Thereby, we simultaneously monitored Neuregulin-dependent mouse ErbB receptor tyrosine kinase dimerization, effector recruitment and downstream signaling.
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Schapansky J, Morissette M, Odero G, Albensi B, Glazner G. Neuregulin β1 enhances peak glutamate-induced intracellular calcium levels through endoplasmic reticulum calcium release in cultured hippocampal neuronsThis article is one of a selection of papers published in a special issue celebrating the 125th anniversary of the Faculty of Medicine at the University of Manitoba. Can J Physiol Pharmacol 2009; 87:883-91. [DOI: 10.1139/y09-082] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Modulation of intracellular free calcium levels is the primary second messenger system of the neuronal glutamatergic system, playing a role in regulation of all major cellular processes. The protein neuregulin (NRG) β1 acts as an extracellular signaling ligand in neurons, rapidly regulating currents through ionotropic glutamate receptors. The effect NRG may have on glutamate-induced changes in intracellular free calcium concentrations has not been examined, however. In this study, cultured embryonic rat hippocampal neurons were treated with NRGβ1 to determine a possible effect on glutamate-induced intracellular calcium levels. Long-term (24 h), but not short-term (1 h), incubation with NRGβ1 resulted in a significantly greater glutamate-mediated acute peak elevation of intracellular calcium levels than occurred in vehicle-treated neurons. Long-term NRGβ1 incubation significantly enhanced calcium increase induced by specific stimulation of metabotropic glutamate receptors, but did not significantly alter the N-methyl d-aspartate (NMDA)- or KCl-induced calcium increase and paradoxically decreased the effect of α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) treatment on intracellular calcium. Metabotropic glutamate receptors cause increased intracellular free calcium via release of calcium from intracellular stores; thus this system was examined in more detail. NRGβ1 treatment significantly (greater than 2-fold) enhanced calcium release from endoplasmic reticulum stores after stimulation of ryanodine receptors with caffeine, but did not significantly increase calcium release from endoplasmic reticulum mediated by inositol trisphosphate (IP3) receptors. In addition, ryanodine receptor inhibition with ruthenium red prevented the glutamate-induced increase in intracellular calcium levels in NRGβ1-treated neurons. These data show that long-term NRGβ1 treatment can enhance glutamate-induced peak intracellular calcium levels through metabotropic glutamate receptor activation by increasing endoplasmic reticulum calcium release through ryanodine receptors.
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Affiliation(s)
- Jason Schapansky
- Division of Neurodegenerative Disorders, St. Boniface General Hospital Research Centre, Department of Pharmacology, University of Manitoba, 4052–351 Tache Avenue, Winnipeg, MB R2H 2A6, Canada
| | - Marc Morissette
- Division of Neurodegenerative Disorders, St. Boniface General Hospital Research Centre, Department of Pharmacology, University of Manitoba, 4052–351 Tache Avenue, Winnipeg, MB R2H 2A6, Canada
| | - Gary Odero
- Division of Neurodegenerative Disorders, St. Boniface General Hospital Research Centre, Department of Pharmacology, University of Manitoba, 4052–351 Tache Avenue, Winnipeg, MB R2H 2A6, Canada
| | - Benedict Albensi
- Division of Neurodegenerative Disorders, St. Boniface General Hospital Research Centre, Department of Pharmacology, University of Manitoba, 4052–351 Tache Avenue, Winnipeg, MB R2H 2A6, Canada
| | - Gordon Glazner
- Division of Neurodegenerative Disorders, St. Boniface General Hospital Research Centre, Department of Pharmacology, University of Manitoba, 4052–351 Tache Avenue, Winnipeg, MB R2H 2A6, Canada
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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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Frey MR, Edelblum KL, Mullane MT, Liang D, Polk DB. The ErbB4 growth factor receptor is required for colon epithelial cell survival in the presence of TNF. Gastroenterology 2009; 136:217-26. [PMID: 18973758 PMCID: PMC2811086 DOI: 10.1053/j.gastro.2008.09.023] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/05/2008] [Revised: 08/12/2008] [Accepted: 09/18/2008] [Indexed: 12/02/2022]
Abstract
BACKGROUND & AIMS The ErbB4 receptor tyrosine kinase regulates cell growth, survival, and differentiation in several tissues, but its role in the gastrointestinal tract has not been reported. We tested the hypothesis that ErbB4 promotes intestinal cell survival and restitution following injury or inflammation. METHODS ErbB4 expression in human inflammatory bowel disease was determined by immunohistochemistry. Mice were subjected to dextran sulfate sodium (DSS, 3%) colitis or injected with tumor necrosis factor (TNF), and ErbB4 expression was quantified by immunohistochemistry and Western blot. Cultured young adult mouse colon (YAMC) cells were exposed to TNF, and ErbB4 messenger RNA, protein, and phosphorylation levels were measured. Cells transfected with ErbB4 small interfering RNA (siRNA), or over expressing ErbB4, were subjected to wound healing and apoptosis assays. RESULTS ErbB4 levels increased in Crohn's colitis and the colon epithelium of mice with DSS colitis or injected with TNF. In YAMC cells, TNF induced ErbB4 messenger RNA, protein, and phosphorylation; nuclear factor kappaB activation also stimulated ErbB4 accumulation. ErbB4 siRNA sensitized cells to TNF-stimulated apoptosis, while over expression blocked apoptosis induced by TNF plus cycloheximide. Additionally, ErbB4 siRNA decreased YAMC cell wound healing. ErbB4 knockdown attenuated, while over expression elevated, phosphorylation of Akt in response to TNF. Inhibition of the phosphatidylinositol 3-kinase/Akt signaling cascade reversed the ability of ErbB4 over expression to protect from cytokine-induced apoptosis. CONCLUSIONS ErbB4 expression and signaling are key elements for TNF responses in vivo and in cell culture, protecting intestinal epithelial cells from apoptosis in the inflammatory environment, possibly through Akt activation.
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Affiliation(s)
- Mark R. Frey
- Department of Pediatrics, Division of Gastroenterology, Hepatology & Nutrition, Vanderbilt University School of Medicine Nashville, TN 37232-0696
| | - Karen L. Edelblum
- Department of Cell & Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37232-0696
| | - Matthew T. Mullane
- Department of Pediatrics, Division of Gastroenterology, Hepatology & Nutrition, Vanderbilt University School of Medicine Nashville, TN 37232-0696
| | - Dongchun Liang
- Department of Pediatrics, Division of Gastroenterology, Hepatology & Nutrition, Vanderbilt University School of Medicine Nashville, TN 37232-0696
| | - D. Brent Polk
- Department of Pediatrics, Division of Gastroenterology, Hepatology & Nutrition, Vanderbilt University School of Medicine Nashville, TN 37232-0696,Department of Cell & Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37232-0696
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Developmental disruptions in neural connectivity in the pathophysiology of schizophrenia. Dev Psychopathol 2008; 20:1297-327. [DOI: 10.1017/s095457940800062x] [Citation(s) in RCA: 115] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
AbstractSchizophrenia has been thought of as a disorder of reduced functional and structural connectivity. Recent advances in neuroimaging techniques such as functional magnetic resonance imaging, structural magnetic resonance imaging, diffusion tensor imaging, and small animal imaging have advanced our ability to investigate this hypothesis. Moreover, the power of longitudinal designs possible with these noninvasive techniques enable the study of not just how connectivity is disrupted in schizophrenia, but when this disruption emerges during development. This article reviews genetic and neurodevelopmental influences on structural and functional connectivity in human populations with or at risk for schizophrenia and in animal models of the disorder. We conclude that the weight of evidence across these diverse lines of inquiry points to a developmental disruption of neural connectivity in schizophrenia and that this disrupted connectivity likely involves susceptibility genes that affect processes involved in establishing intra- and interregional connectivity.
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Krivosheya D, Tapia L, Levinson JN, Huang K, Kang Y, Hines R, Ting AK, Craig AM, Mei L, Bamji SX, El-Husseini A. ErbB4-neuregulin signaling modulates synapse development and dendritic arborization through distinct mechanisms. J Biol Chem 2008; 283:32944-56. [PMID: 18819924 DOI: 10.1074/jbc.m800073200] [Citation(s) in RCA: 88] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Perturbations in neuregulin-1 (NRG1)/ErbB4 function have been associated with schizophrenia. Affected patients exhibit altered levels of these proteins and display hypofunction of glutamatergic synapses as well as altered neuronal circuitry. However, the role of NRG1/ErbB4 in regulating synapse maturation and neuronal process formation has not been extensively examined. Here we demonstrate that ErbB4 is expressed in inhibitory interneurons at both excitatory and inhibitory postsynaptic sites. Overexpression of ErbB4 postsynaptically enhances size but not number of presynaptic inputs. Conversely, knockdown of ErbB4 using shRNA decreases the size of presynaptic inputs, demonstrating a specific role for endogenous ErbB4 in synapse maturation. Using ErbB4 mutant constructs, we demonstrate that ErbB4-mediated synapse maturation requires its extracellular domain, whereas its tyrosine kinase activity is dispensable for this process. We also demonstrate that depletion of ErbB4 decreases the number of primary neurites and that stimulation of ErbB4 using a soluble form of NRG1 results in exuberant dendritic arborization through activation of the tyrosine kinase domain of ErbB4 and the phosphoinositide 3-kinase pathway. These findings demonstrate that NRG1/ErbB4 signaling differentially regulates synapse maturation and dendritic morphology via two distinct mechanisms involving trans-synaptic signaling and tyrosine kinase activity, respectively.
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Affiliation(s)
- Daria Krivosheya
- Department of Psychiatry, the Brain Research Center, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada
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A gamma-secretase inhibitor and quinacrine reduce prions and prevent dendritic degeneration in murine brains. Proc Natl Acad Sci U S A 2008; 105:10595-600. [PMID: 18647832 DOI: 10.1073/pnas.0803671105] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
In prion-infected mice, both the Notch-1 intracellular domain transcription factor (NICD) and the disease-causing prion protein (PrP(Sc)) increase in the brain preceding dendritic atrophy and loss. Because the drug LY411575 inhibits the gamma-secretase-catalyzed cleavage of Notch-1 that produces NICD, we asked whether this gamma-secretase inhibitor (GSI) might prevent dendritic degeneration in mice with scrapie. At 50 d postinoculation with Rocky Mountain Laboratory (RML) prions, mice were given GSI orally for 43-60 d. Because we did not expect GSI to produce a reduction of PrP(Sc) levels in brain, we added quinacrine (Qa) to the treatment regimen. Qa inhibits PrP(Sc) formation in cultured cells. The combination of GSI and Qa reduced PrP(Sc) by approximately 95% in the neocortex and hippocampus but only approximately 50% in the thalamus at the site of prion inoculation. The GSI plus Qa combination prevented dendritic atrophy and loss, but GSI alone did not. Even though GSI reduced NICD levels to a greater extent than GSI plus Qa, it was unable to prevent dendritic degeneration. Whether a balance between NICD and dendrite growth-stimulating factors was achieved with GSI plus Qa but not GSI alone remains to be determined. Although the combination of GSI and Qa diminished PrP(Sc) in the brains of RML-infected mice, GSI toxicity prevented us from being able to assess the effect the GSI plus Qa combination on incubation times. Whether less toxic GSIs can be used in place of LY411575 to prolong survival remains to be determined.
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Di Segni A, Farin K, Pinkas-Kramarski R. Identification of nucleolin as new ErbB receptors- interacting protein. PLoS One 2008; 3:e2310. [PMID: 18523588 PMCID: PMC2390759 DOI: 10.1371/journal.pone.0002310] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2008] [Accepted: 04/15/2008] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND The ErbB receptor tyrosine kinases are major contributors to malignant transformation. These receptors are frequently overexpressed in a variety of human carcinomas. The role of the ErbB receptors and their ligands in carcinomas and the mechanism by which their overexpression leads to cancer development is still unclear. Ligand binding to specific ErbB receptor is followed by receptor dimerization, phosphorylation and recruitment of SH2 containing cytoplasmic proteins, which initiate the cascade of signaling events. Nevertheless, increasing data suggest that there are non-phosphorylated receptor-substrate interactions that may affect ErbB-mediated responses. METHODOLOGY/PRINCIPAL FINDINGS In the present study, using GST-ErbB4 fusion protein pull down assay and mass spectroscopic analysis, we have found the ErbB receptors interact with nucleolin via their cytoplasmic tail. Nucleolin is a ubiquitous, nonhistone, nucleolar, multifunctional phosphoprotein that is also overexpressed in cancer cells. Our results demonstrate that overexpression of ErbB1 and nucleolin may lead to receptor dimerization, phosphorylation and to anchorage independent growth. CONCLUSIONS/SIGNIFICANCE The oncogenic potential of ErbB depends on receptor levels and activation. Our results suggest that nucleolin may affect ErbB dimerization and activation leading to enhanced cell growth.
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Affiliation(s)
- Ayelet Di Segni
- Department of Neurobiology, Tel-Aviv University, Ramat-Aviv, Israel
| | - Keren Farin
- Department of Neurobiology, Tel-Aviv University, Ramat-Aviv, Israel
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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: 772] [Impact Index Per Article: 48.3] [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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Developmental Regulation of Neuregulin1 Isoforms and erbB Receptor Expression in Intact Rat Dorsal Root Ganglia. Neurochem Res 2008; 34:17-22. [DOI: 10.1007/s11064-008-9732-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2008] [Accepted: 04/29/2008] [Indexed: 11/27/2022]
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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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Neuroprotective effects of neuregulin-1 on B35 neuronal cells following ischemia. Brain Res 2008; 1210:39-47. [PMID: 18410912 DOI: 10.1016/j.brainres.2008.02.059] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2007] [Revised: 02/06/2008] [Accepted: 02/13/2008] [Indexed: 01/16/2023]
Abstract
We previously showed that neuregulin-1 (NRG-1) protected neurons from death in vivo following focal ischemia. The goal of this study was to develop an in vitro rat ischemia model to examine the cellular and molecular mechanisms involved in the neuroprotective effects of NRG-1 on ischemia-induced neuronal death. Rat B-35 neuroblastoma cells differentiated by serum withdrawal, developed enhanced neuronal characteristics including, neurite extension and upregulation of neuronal markers of differentiation. When B35 neurons were subjected to oxygen glucose deprivation (OGD)/reoxygenation or glutamate, widespread neuronal death was seen after both treatments. Treatment with NRG-1 immediately after OGD significantly increased neuronal survival. NRG-1 administration also resulted in a significant decrease in annexin V, an early marker of apoptosis. However, the neurotoxic actions of glutamate were unaffected by NRG-1. The neuroprotective effects of NRG-1 were prevented by an inhibitor of the phosphatidylinositol-3-kinase/Akt pathway. These results provide a new model to gain insight into the mechanisms employed by NRG-1 to protect neurons from ischemic brain injury.
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Hayes NVL, Blackburn E, Smart LV, Boyle MM, Russell GA, Frost TM, Morgan BJT, Baines AJ, Gullick WJ. Identification and characterization of novel spliced variants of neuregulin 4 in prostate cancer. Clin Cancer Res 2007; 13:3147-55. [PMID: 17545517 DOI: 10.1158/1078-0432.ccr-06-2237] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
PURPOSE The neuregulin (NRG) 1, 2, and 3 genes undergo extensive alternative mRNA splicing, which results in variants that show structural and functional diversity. The aims of this study were to establish whether the fourth member of this family, NRG4, is expressed in prostate cancer, if it is alternatively spliced and whether any functional differences between the variants could be observed. EXPERIMENTAL DESIGN The expression of NRG4 was determined using immunohistochemical staining of 40 cases of primary prostate cancer. Bioinformatic analysis and reverse transcription-PCR (RT-PCR) using NRG4 isotype-specific primers on a panel of normal and prostate cancer cell lines were used to identify alternatively spliced NRG4 variants. Expression of these variants was determined using isotype-specific antibodies. Transfection into Cos-7 cells of two of these green fluorescent protein-tagged variants allowed analysis of their subcellular location. Four of the variants were chemically synthesized and tested for their ability to activate the ErbB4 receptor. RESULTS NRG4 was variably expressed in the cytoplasm in the majority of prostate cancer cases, and in a subset of cases in the membrane, high levels were associated with advanced disease stage. Four novel NRG4 splice variants (NRGA2, NRG4 B1-3) were characterized, where each seemed to have a different subcellular location and were also expressed in the cytoplasm of the prostate tumors. NRG4 B3 was also present in endothelial cells. In transfected cells, the A type variant (NRG4 A1) was localized to the membrane, whereas the B type variant (NRG4 B1), which lacks the predicted transmembrane region, had an intracellular localization. Only the variants with an intact epidermal growth factor-like domain activated ErbB4 signaling. CONCLUSION NRG4 overexpression is associated with advanced-stage prostate cancer. The alternative splice variants may have different roles in cell signaling, some acting as classic receptor ligands and some with as-yet unknown functions.
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Affiliation(s)
- Nandini V L Hayes
- Cancer Biology Laboratory, Research School of Biosciences, Centre for Biomedical Informatics, Institute of Mathematics and Statistics, University of Kent, Canterbury, UK.
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Hayes NVL, Newsam RJ, Baines AJ, Gullick WJ. Characterization of the cell membrane-associated products of the Neuregulin 4 gene. Oncogene 2007; 27:715-20. [PMID: 17684490 DOI: 10.1038/sj.onc.1210689] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The NRG4 gene is a member of a family of four genes that encode a class of epidermal growth factors. This gene has been reported to express a protein designated here as NRG4A1. We describe here a novel splice variant of the NRG4 gene, NRG4A2, which encodes a C-terminal region containing a predicted type I PDZ-binding peptide. Both NRG4A1 and NRG4A2 were shown to be expressed on the cell surface, as expected by the presence of a predicted transmembrane sequence, and were modified at a single N-linked glycosylation site in the extracellular domain. Significant stabilization of expression of both proteins was seen in the presence of the proteosome inhibitor MG-132 suggesting that they are normally degraded by this system. N-terminal cleavage was inhibited in both isotypes by the broad-spectrum matrix metalloproteinase inhibitor, galardin (GM 6001). A glycosylated, secreted form of NRG4A1 was detected in the cell medium which showed biological activity in two assays, phosphorylation of the HER4 receptor and stimulation of neurite formation in PC-12 cells stably expressing HER4. Transfection and expression of green fluorescent protein-tagged proteins and immunofluorescent staining with specific anti-peptide antibodies showed that NRG4A1 is localized to membrane ruffles, while NRG4A2 has a more punctate membrane distribution.
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Affiliation(s)
- N V L Hayes
- Cancer Biology Laboratory, Research School of Biosciences, University of Kent, Canterbury, UK
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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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Bellon A. New genes associated with schizophrenia in neurite formation: a review of cell culture experiments. Mol Psychiatry 2007; 12:620-9. [PMID: 17440437 DOI: 10.1038/sj.mp.4001985] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
New genes consistently associated with schizophrenia include NRG1, Akt, DISC-1 and dysbindin-1. Since these genes participate in neurotransmission, neuroplasticity and neurodevelopment it has not been easy to elucidate which of these roles are abnormal in patients with schizophrenia. Neurite formation is identified as a crucial stage in development, and it is proposed that a defect in neurite formation originating from abnormally encoded proteins by these new genes could be at least an in vitro marker that reflects the most consistent molecular and neuroanatomical findings in schizophrenia. A systematic review of the literature linking the process of neurite formation to genes with replicated evidence that supported their association with schizophrenia was conducted. In addition, an outline of the process of neurite formation was included. Neurite formation was shown to be induced by neuregulins, the product of the gene NRG1. The activation of Akt, a serine/threonine kinase, promoted neurite formation in six independent studies. Conversely, two studies found that Akt inhibits neurite outgrowth. Stronger evidence supporting an association with the new genes related to schizophrenia and neurite formation comes from DISC-1. Defects in DISC-1 protein were shown to directly alter the process of neurite formation. Dysbindin-1 has not yet been directly implicated in neurite outgrowth. These findings suggest that the proteins encoded by NRG1, Akt and DISC-1 are implicated in the process of neurite formation in cellular models as well as, at least in part, animal models during development. Abnormalities in this process could have potential etiologic implications for schizophrenia. Direct evidence, however, of abnormal neurite formation in patients with schizophrenia is still missing. Limitations to this model are identified.
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Affiliation(s)
- A Bellon
- Menninger Department of Psychiatry & Behavioral Sciences, Baylor College of Medicine, Houston, TX 77030, USA.
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Tal-Or P, Erlich S, Porat-Shliom N, Goldshmit Y, Ben-Baruch G, Shaharabani E, Kloog Y, Pinkas-Kramarski R. Ligand-independent regulation of ErbB4 receptor phosphorylation by activated Ras. J Cell Biochem 2006; 98:1482-94. [PMID: 16518842 DOI: 10.1002/jcb.20815] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The ErbB family of receptor tyrosine kinases regulates cell growth, differentiation and survival. Activation of the receptors is induced by specific growth factors in an autocrine, paracrine or juxtacrine manner. The activated ErbB receptors turn on a large variety of signaling cascades, including the prominent Ras-dependent signaling pathways. The activated Ras can induce secretion of growth factors such as EGF and neuregulin, which activate their respective receptors. In the present study, we demonstrate for the first time that activated Ras can activate ErbB4 receptor in a ligand-independent manner. Expression of constitutively active H-Ras(12V), K-Ras(12V) or N-Ras(13V) in PC12-ErbB4 cells induced ErbB4-receptor phosphorylation, indicating that each of the most abundant Ras isoforms can induce receptor activation. NRG-induced phosphorylation of ErbB4 receptor was blocked by the soluble ErbB4 receptor, which had no effect on the Ras-induced receptor phosphorylation. Moreover, conditioned medium from H-Ras(12V)-transfected PC12-ErbB4 cells had no effect on receptor phosphorylation. It thus indicates that Ras induces ErbB4 phosphorylation in a ligand-independent manner. Each of the Ras effector domain mutants, H-Ras(12V)S35, H-Ras(12V)C40, and H-Ras(12V)G37, which respectively activate Raf1, PI3K, and RalGEF, induced a small but significant receptor phosphorylation. The PI3K inhibitor LY294002 and the MEK inhibitor PD98059 caused a partial inhibition of the Ras-induced ErbB4 receptor phosphorylation. Using a mutant ErbB4 receptor, which lacks kinase activity, we demonstrated that the Ras-mediated ErbB4 phosphorylation depends on the kinase activity of the receptor and facilitates ligand-independent neurite outgrowth in PC12-ErbB4 cells. These experiments demonstrate a novel mechanism controlling ErbB receptor activation. Ras induces ErbB4 receptor phosphorylation in a non-autocrine manner and this activation depends on multiple Ras effector pathways and on ErbB4 kinase activity.
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Affiliation(s)
- Pazit Tal-Or
- Department of Neurobiochemistry, Tel Aviv University, Ramat Aviv, 69978, Israel
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du Bois TM, Huang XF. Early brain development disruption from NMDA receptor hypofunction: relevance to schizophrenia. ACTA ACUST UNITED AC 2006; 53:260-70. [PMID: 17014910 DOI: 10.1016/j.brainresrev.2006.09.001] [Citation(s) in RCA: 94] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2006] [Revised: 09/01/2006] [Accepted: 09/03/2006] [Indexed: 01/28/2023]
Abstract
Disruption to brain development at an early stage can potentially alter chemically coded neural networks and can affect behavior in later life. During early brain development antagonism of glutamate NMDA receptors, which play an important role in neuronal outgrowth and survival, leads to neuronal damage in several brain regions and causes behavioral alterations in rodents that mimic schizophrenia symptoms and endophenotypes. There are several lines of evidence implicating involvement of a dysfunctional glutamate system in schizophrenia. In normal subjects, NMDA receptor antagonists produce behavioral and neurochemical changes that mimic schizophrenia symptoms better than any other psychotomimetic drug. Moreover, these drugs worsen symptoms in schizophrenia patients and can trigger a recrudescence of the acute psychotic state in patients with stable chronic schizophrenia. In addition, genes consistently reported as being altered in schizophrenia play roles in development, neuroplasticity and glutamate/GABAergic neurotransmission. Perinatal NMDA receptor antagonist treatment is a useful model for studying the neurodevelopmental and NMDA receptor hypofunction hypotheses of schizophrenia because neurochemical and behavioral changes, reminiscent of those seen in schizophrenia, are present long after cessation of drug administration, which suggests that a permanent change in brain structure and organization has occurred during brain development.
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Affiliation(s)
- Teresa Marie du Bois
- Neuroscience Institute for Schizophrenia and Allied Disorders (NISAD), Australia.
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Castillo C, Malavé C, Martínez JC, Núñez J, Hernández D, Pasquali F, Villegas GM, Villegas R. Neuregulin-1 isoform induces mitogenesis, KCa and Ca2+ currents in PC12 cells. A comparison with sciatic nerve conditioned medium. Brain Res 2006; 1110:64-75. [PMID: 16859657 DOI: 10.1016/j.brainres.2006.06.058] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2006] [Revised: 05/31/2006] [Accepted: 06/19/2006] [Indexed: 11/20/2022]
Abstract
Neuregulin-1 (NRG-1) is an active component found in sciatic nerve conditioned medium (CM). NRG-1 is a growth and differentiation factor shown to have an effect on neuritogenesis and survival of neural cells. PC12 cells chronically treated with NRG-1 (beta1 isoform) show an increase in proliferation under low-serum condition (2.5% fetal bovine serum and 1.25% horse serum) and serum deprivation, without visible morphological changes. NRG-1 and CM treatments of PC12 cells induced an increase of voltage-activated Ca2+ currents and large-conductance calcium-activated K+ currents (KCa). AG825, a specific inhibitor for erbB2 receptor, abolishes KCa current, though Ca2+ currents were not inhibited. These results showed that NRG-1 is capable of inducing functional changes but is not sufficient on its own to have an effect on cell morphology.
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Affiliation(s)
- Cecilia Castillo
- Centro de Biociencias y Medicina Molecular, Instituto de Estudios Avanzados-IDEA, Apartado 17606, Caracas, Venezuela.
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46
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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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47
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Guo WP, Wang J, Li RX, Peng YW. Neuroprotective effects of neuregulin-1 in rat models of focal cerebral ischemia. Brain Res 2006; 1087:180-5. [PMID: 16616052 DOI: 10.1016/j.brainres.2006.03.007] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2005] [Revised: 02/27/2006] [Accepted: 03/01/2006] [Indexed: 10/24/2022]
Abstract
The purpose of this study was to investigate the therapeutic efficacy and mechanism of recombinant human NRG-1 to attenuate ischemia/reperfusion brain injury. NRG-1(3.0 ng/kg) was applied intravascularly 10 min before middle cerebral artery occlusion (MCAO) and then focal cerebral ischemia for 90 min and reperfusion for 24 h. The rats were scored post-reperfusion for neurological deficits and infarct volume in the brain was assessed by 2,3,5-triphenyltetrazolium chloride(TTC). Apoptosis was evaluated by TUNEL staining. Reverse transcription polymerase chain reaction (RT-PCR) was used to measure changes of caspase-3 mRNA. The level of TNF-alpha was determined using enzyme-linked immunosorbent assay (ELISA). Our results demonstrated that recombinant human NRG-1 could reduce cerebral infarct volume by about 71% (P < 0.05) and TUNEL positive cells when given immediately before MCAO, and improved behavior of animals. Furthermore, we also showed that NRG-1 could also decrease the expression of caspase-3 mRNA and production of TNF-alpha protein. These data suggest that pre-administration of NRG-1 attenuates cerebral ischemia and reperfusion injury. This protective effect may be involved in the inhibition of caspase-3 and TNF-alpha.
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Affiliation(s)
- Wen-Ping Guo
- Department of Anatomy, Shanghai Medical College, Fudan University, 138 YiXue Yuan Road, Shanghai 200032, PR China.
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Xu Z, Croslan DR, Harris AE, Ford GD, Ford BD. Extended therapeutic window and functional recovery after intraarterial administration of neuregulin-1 after focal ischemic stroke. J Cereb Blood Flow Metab 2006; 26:527-35. [PMID: 16136057 DOI: 10.1038/sj.jcbfm.9600212] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
We have previously shown that neuregulin-1 (NRG-1) protects neurons from ischemic brain injury if administered before focal stroke. Here, we examined the therapeutic window and functional recovery after NRG-1 treatment in rats subjected to 90 mins of middle cerebral artery occlusion (MCAO) and 24 h of reperfusion. Neuregulin-1 (2.5 microg/kg [corrected] bolus, 1.25 microg/kg/min [corrected] infusion) reduced infarct volume by 89.2%+/-41.9% (mean+/-s.d.; n=8; P<0.01) if administered immediately after the onset of reperfusion. Neuroprotection was also evident if NRG-1 was administered 4 h (66.4%+/-52.6%; n=7; P<0.01) and 12 h (57.0%+/-20.8%; n=8; P<0.01) after reperfusion. Neuregulin-1 administration also resulted in a significant improvement of functional neurologic outcome compared with vehicle-treated animals (32.1%+/-5.7%; n=9; P<0.01). The neuroprotective effect of the single administration of NRG-1 was seen as long as 2 weeks after treatment. Neurons labeled with the neurodegeneration marker dye Fluoro-JadeB were observed after MCAO in the cortex, but the numbers were significantly reduced after NRG-1 treatment. These results indicate that NRG-1 is a potent neuroprotective compound with an extended therapeutic window that has practical therapeutic potential in treating individuals after ischemic brain injury.
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Affiliation(s)
- Zhenfeng Xu
- Department of Anatomy and Neurobiology, Neuroscience Institute, Morehouse School of Medicine, Atlanta, Georgia 30310, USA
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Linggi B, Cheng QC, Rao AR, Carpenter G. The ErbB-4 s80 intracellular domain is a constitutively active tyrosine kinase. Oncogene 2006; 25:160-3. [PMID: 16170367 DOI: 10.1038/sj.onc.1209003] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The ErbB-4 receptor tyrosine kinase homo- and heterodimerizes following heregulin binding, which provokes increased levels of tyrosine autophosphorylation. Unique to the ErbB family, ErbB-4 is then proteolytically cleaved by alpha- and gamma-secretase to produce an 80 kDa intracellular domain (s80 ICD) fragment. This fragment is found in both the cytoplasm and nucleus of many normal and cancer cells and can interact with transcription factors in the cytoplasm and nucleus. Since the s80 ICD lacks ectodomain sequences known to play a major role in dimerization of ErbB family members, we asked whether the s80 ICD is an active tyrosine kinase. Here, we demonstrate that the s80 ICD is a constitutively active tyrosine kinase and can form homodimers. The s80 ICD is autophosphorylated in cells and can phosphorylate an exogenous substrate in vitro. Also, the s80 ICD can coassociate and dimers are detected by chemical crosslinking. This is the first example of constitutive kinase activation and dimerization totally within the cytoplasmic domain of an ErbB receptor and suggests that the s80 ICD may function to phosphorylate substrates in the cytoplasm or nucleus.
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Affiliation(s)
- B Linggi
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN 37232-0146, USA
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50
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Bacsi A, Stanton GJ, Hughes TK, Kruze M, Boldogh I. Colostrinin-Driven Neurite Outgrowth Requires p53 Activation in PC12 Cells. Cell Mol Neurobiol 2005; 25:1123-39. [PMID: 16392041 DOI: 10.1007/s10571-005-8222-6] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2004] [Accepted: 08/29/2005] [Indexed: 10/25/2022]
Abstract
1. Colostrinin (CLN) induces maturation and differentiation of murine thymocytes, promotes proliferation of peripheral blood leukocytes, induces immunomodulator cytokines, and ameliorates oxidative stress-mediated activation of c-Jun NH2-terminal kinases. 2. Here we report that upon treatment with CLN, medullary pheochromocytoma (PC12) cells ceased to proliferate and extend neurites. 3. The arrest of CLN-treated PC12 cells in the G1 phase of the cell cycle was due to an increase in the phosphorylation of p53 at serine(15) (p53ser15) and expression of p21WAF1. PC12 cells treated with inhibitory oligonucleotides to p53 lacked p53ser15 and p21WAF1 expression, and did not show morphological changes after CLN exposure. Transfection with inhibitory oligonucleotides to p21WAF1 had no effect on p53 activation; however, cells failed to arrest or extend neurites. An oligonucleotide inhibiting luciferase expression had no effect on CLN-mediated p53 activation, p21WAF1 expression, growth arrest, or neurite outgrowth. 4. We conclude that CLN induces delicate cassettes of signaling pathways common to cell proliferation and differentiation, and mediates activities that are similar to those of hormones and neurotrophins, leading to neurite outgrowth.
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Affiliation(s)
- Attila Bacsi
- Department of Microbiology and Immunology, University of Texas Medical Branch at Galveston, Galveston, TX 77555, USA
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