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Scharr M, Hirt B, Neckel PH. Spatial gene expression profile of Wnt-signaling components in the murine enteric nervous system. Front Immunol 2024; 15:1302488. [PMID: 38322254 PMCID: PMC10846065 DOI: 10.3389/fimmu.2024.1302488] [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: 09/26/2023] [Accepted: 01/02/2024] [Indexed: 02/08/2024] Open
Abstract
Introduction Wnt-signaling is a key regulator of stem cell homeostasis, extensively studied in the intestinal crypt and other metazoan tissues. Yet, there is hardly any data available on the presence of Wnt-signaling components in the adult enteric nervous system (ENS) in vivo. Methods Therefore, we employed RNAscope HiPlex-assay, a novel and more sensitive in situ hybridization technology. By amplifying target specific signals, this technique enables the detection of low abundance, tightly regulated RNA content as is the case for Wnt-signaling components. Additionally, we compared our data to previously published physiological single cell RNA and RiboTag-based RNA sequencing analyses of enteric gliosis using data-mining approaches. Results Our descriptive analysis shows that several components of the multidi-mensional regulatory network of the Wnt-signaling pathway are present in the murine ENS. The transport and secretion protein for Wnt-ligands Wntless as well as canonical (Wnt3a and Wnt2b) and non-canonical Wnt-ligands (Wnt5a, Wnt7a, Wnt8b and Wnt11) are detectable within submucosal and myenteric plexus. Further, corresponding Frizzled receptors (Fzd1, Fzd3, Fzd6, and Fzd7) and regulatory signaling mediators like R-Spondin/DKK ligands are present in the ENS of the small and large intestine. Further, data mining approaches revealed, that several Wnt-related molecules are expressed by enteric glial cell clusters and are dynamically regulated during the inflammatory manifestation of enteric gliosis. Discussion Our results suggest, that canonical and non-canonical Wnt-signaling has a much broader impact on the mature ENS and its cellular homeostasis in health and inflammation, than previously anticipated.
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Affiliation(s)
| | | | - Peter H. Neckel
- Institute of Clinical Anatomy and Cell Analysis, University of Tübingen, Tübingen, Germany
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Scharr M, Scherer S, Hirt B, Neckel PH. Dickkopf1 induces enteric neurogenesis and gliogenesis in vitro if apoptosis is evaded. Commun Biol 2023; 6:808. [PMID: 37532804 PMCID: PMC10397193 DOI: 10.1038/s42003-023-05072-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2022] [Accepted: 06/25/2023] [Indexed: 08/04/2023] Open
Abstract
Neurogenesis in the postnatal enteric nervous system (ENS) is controversially discussed. Yet, deciphering the regenerative potential of the ENS is essential for our understanding and therapy of human enteric neuropathies. Dickkopf1 (DKK1) is a Wnt-antagonist and involved in the homeostasis of various tissues. We hypothesize that DKK1 could function as a negative regulator on the proliferation of ENS-progenitors in the postnatal gut of mice and human infants. Here, we provide evidence that DKK1 is expressed in the murine and human ENS. If applied to ENS-progenitors in vitro, DKK1 leads to an increased proliferation, however, followed by extensive apoptosis. Yet, once we block apoptosis, DKK1-stimulation markedly increases enteric neurogenesis in murine and human ENS-progenitors. Thus, DKK1 is a strong, ambivalent regulator of the ENS-progenitor cell pool in mice and humans. These results are fundamental steps to reshaping our understanding of the homeostasis of the ENS in health and disease.
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Affiliation(s)
- Melanie Scharr
- Institute of Clinical Anatomy and Cell Analysis, University of Tübingen, Tübingen, Germany
| | - Simon Scherer
- Department of Pediatric Surgery and Urology, University Children's Hospital Tübingen, Tübingen, Germany
| | - Bernhard Hirt
- Institute of Clinical Anatomy and Cell Analysis, University of Tübingen, Tübingen, Germany
| | - Peter H Neckel
- Institute of Clinical Anatomy and Cell Analysis, University of Tübingen, Tübingen, Germany.
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Glia and Neural Stem and Progenitor Cells of the Healthy and Ischemic Brain: The Workplace for the Wnt Signaling Pathway. Genes (Basel) 2020; 11:genes11070804. [PMID: 32708801 PMCID: PMC7397164 DOI: 10.3390/genes11070804] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Revised: 07/10/2020] [Accepted: 07/15/2020] [Indexed: 12/14/2022] Open
Abstract
Wnt signaling plays an important role in the self-renewal, fate-commitment and survival of the neural stem/progenitor cells (NS/PCs) of the adult central nervous system (CNS). Ischemic stroke impairs the proper functioning of the CNS and, therefore, active Wnt signaling may prevent, ameliorate, or even reverse the negative effects of ischemic brain injury. In this review, we provide the current knowledge of Wnt signaling in the adult CNS, its status in diverse cell types, and the Wnt pathway’s impact on the properties of NS/PCs and glial cells in the context of ischemic injury. Finally, we summarize promising strategies that might be considered for stroke therapy, and we outline possible future directions of the field.
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Esteve P, Crespo I, Kaimakis P, Sandonís A, Bovolenta P. Sfrp1 Modulates Cell-signaling Events Underlying Telencephalic Patterning, Growth and Differentiation. Cereb Cortex 2020; 29:1059-1074. [PMID: 30084950 DOI: 10.1093/cercor/bhy013] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2017] [Accepted: 01/09/2018] [Indexed: 12/19/2022] Open
Abstract
The mammalian dorsal telencephalic neuroepithelium develops-from medial to lateral-into the choroid plaque, cortical hem, hippocampal primordium and isocortex under the influence of Bmp, Wnt and Notch signaling. Correct telencephalic development requires a tight coordination of the extent/duration of these signals, but the identification of possible molecular coordinators is still limited. Here, we postulated that Secreted Frizzled Related Protein 1 (Sfrp1), a multifunctional regulator of Bmp, Wnt and Notch signaling strongly expressed during early telencephalic development, may represent 1 of such molecules. We report that in E10.5-E12.5 Sfrp1-/- embryos, the hem and hippocampal domains are reduced in size whereas the prospective neocortex is medially extended. These changes are associated with a significant reduction of the medio-lateral telencephalic expression of Axin2, a read-out of Wnt/βcatenin signaling activation. Furthermore, in the absence of Sfrp1, Notch signaling is increased, cortical progenitor cell cycle is shorter, with expanded progenitor pools and enhanced generation of early-born neurons. Hence, in postnatal Sfrp1-/- animals the anterior hippocampus is reduced and the neocortex is shorter in the antero-posterior and medio-lateral axis but is thicker. We propose that, by controlling Wnt and Notch signaling in opposite directions, Sfrp1 promotes hippocampal patterning and balances medio-lateral and antero-posterior cortex expansion.
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Affiliation(s)
- Pilar Esteve
- Centro de Biología Molecular "Severo Ochoa", CSIC-UAM and CIBER de Enfermedades Raras (CIBERER), c/Nicolás Cabrera, Madrid, Spain
| | - Inmaculada Crespo
- Centro de Biología Molecular "Severo Ochoa", CSIC-UAM and CIBER de Enfermedades Raras (CIBERER), c/Nicolás Cabrera, Madrid, Spain
| | - Polynikis Kaimakis
- Centro de Biología Molecular "Severo Ochoa", CSIC-UAM and CIBER de Enfermedades Raras (CIBERER), c/Nicolás Cabrera, Madrid, Spain
| | - Africa Sandonís
- Centro de Biología Molecular "Severo Ochoa", CSIC-UAM and CIBER de Enfermedades Raras (CIBERER), c/Nicolás Cabrera, Madrid, Spain
| | - Paola Bovolenta
- Centro de Biología Molecular "Severo Ochoa", CSIC-UAM and CIBER de Enfermedades Raras (CIBERER), c/Nicolás Cabrera, Madrid, Spain
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Draxin-mediated Regulation of Granule Cell Progenitor Differentiation in the Postnatal Hippocampal Dentate Gyrus. Neuroscience 2020; 431:184-192. [PMID: 32081722 DOI: 10.1016/j.neuroscience.2020.02.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2019] [Revised: 02/04/2020] [Accepted: 02/05/2020] [Indexed: 02/03/2023]
Abstract
The hippocampus is characterized by the presence of life-long neurogenesis. To elucidate the molecular mechanism regulating hippocampal neurogenesis, we studied the functions of the chemorepellent Draxin in neuronal proliferation and differentiation in the postnatal dentate gyrus. The present in vivo cell labeling and fate tracking analyses revealed enhanced differentiation of hippocampal neural stem and progenitor cells (hNSPCs) in the subgranular zone (SGZ) of Draxin-deficient mice. We observed a reduction in the number of BrdU-pulse labeled or Ki-67 immunopositive SGZ cells in the mutant mice. However, Draxin deficiency did not affect cell cycle duration of SGZ cells. In situ hybridization analysis indicated that the receptor component of the canonical Wnt pathway, Lrp6, is expressed in SGZ cells, including Nestin and Sox2 double-positive hNSPCs. Taken together with the previous finding that Draxin interacts physically with Lrp6, we postulate that Draxin plays a pivotal role in the regulation of Wnt-driven hNSPC differentiation to modulate the rate of neuronal differentiation in the progenitor population.
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Bem J, Brożko N, Chakraborty C, Lipiec MA, Koziński K, Nagalski A, Szewczyk ŁM, Wiśniewska MB. Wnt/β-catenin signaling in brain development and mental disorders: keeping TCF7L2 in mind. FEBS Lett 2019; 593:1654-1674. [PMID: 31218672 PMCID: PMC6772062 DOI: 10.1002/1873-3468.13502] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2019] [Revised: 06/13/2019] [Accepted: 06/14/2019] [Indexed: 12/12/2022]
Abstract
Canonical Wnt signaling, which is transduced by β-catenin and lymphoid enhancer factor 1/T cell-specific transcription factors (LEF1/TCFs), regulates many aspects of metazoan development and tissue renewal. Although much evidence has associated canonical Wnt/β-catenin signaling with mood disorders, the mechanistic links are still unknown. Many components of the canonical Wnt pathway are involved in cellular processes that are unrelated to classical canonical Wnt signaling, thus further blurring the picture. The present review critically evaluates the involvement of classical Wnt/β-catenin signaling in developmental processes that putatively underlie the pathology of mental illnesses. Particular attention is given to the roles of LEF1/TCFs, which have been discussed surprisingly rarely in this context. Highlighting recent discoveries, we propose that alterations in the activity of LEF1/TCFs, and particularly of transcription factor 7-like 2 (TCF7L2), result in defects previously associated with neuropsychiatric disorders, including imbalances in neurogenesis and oligodendrogenesis, the functional disruption of thalamocortical circuitry and dysfunction of the habenula.
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Affiliation(s)
- Joanna Bem
- Centre of New TechnologiesUniversity of WarsawPoland
| | - Nikola Brożko
- Centre of New TechnologiesUniversity of WarsawPoland
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Ma L, Wang Y, Hui Y, Du Y, Chen Z, Feng H, Zhang S, Li N, Song J, Fang Y, Xu X, Shi L, Zhang B, Cheng J, Zhou S, Liu L, Zhang X. WNT/NOTCH Pathway Is Essential for the Maintenance and Expansion of Human MGE Progenitors. Stem Cell Reports 2019; 12:934-949. [PMID: 31056478 PMCID: PMC6524734 DOI: 10.1016/j.stemcr.2019.04.007] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2018] [Revised: 04/04/2019] [Accepted: 04/08/2019] [Indexed: 12/18/2022] Open
Abstract
Medial ganglionic eminence (MGE)-like cells yielded from human pluripotent stem cells (hPSCs) hold great potentials for cell therapies of related neurological disorders. However, cues that orchestrate the maintenance versus differentiation of human MGE progenitors, and ways for large-scale expansion of these cells have not been investigated. Here, we report that WNT/CTNNB1 signaling plays an essential role in maintaining MGE-like cells derived from hPSCs. Ablation of CTNNB1 in MGE cells led to precocious cell-cycle exit and advanced neuronal differentiation. Activation of WNT signaling through genetic or chemical approach was sufficient to maintain MGE cells in an expandable manner with authentic neuronal differentiation potencies through activation of endogenous NOTCH signaling. Our findings reveal that WNT/NOTCH signaling cascade is a key player in governing the maintenance versus terminal differentiation of MGE progenitors in humans. Large-scale expansion of functional MGE progenitors for cell therapies can therefore be achieved by modifying WNT/NOTCH pathway. WNT/CTNNB1 signaling is robustly activated in specified human MGE progenitors Ablation of CTNNB1 in human MGE cells leads to advanced neuronal differentiation Activation of WNT signaling maintains MGE progenitors in a proliferative state WNT/CTNNB1 signaling maintains MGE progenitors via activation of NOTCH signaling
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Affiliation(s)
- Lin Ma
- Brain and Spinal Cord Innovative Research Center, Tongji Hospital, Tongji University School of Medicine, Shanghai 200065, China; Key Laboratory of Neuroregeneration of Shanghai Universities, Tongji University School of Medicine, 1239 Siping Road, Room 508, Shanghai 200092, China
| | - Yiran Wang
- Brain and Spinal Cord Innovative Research Center, Tongji Hospital, Tongji University School of Medicine, Shanghai 200065, China; Key Laboratory of Neuroregeneration of Shanghai Universities, Tongji University School of Medicine, 1239 Siping Road, Room 508, Shanghai 200092, China
| | - Yi Hui
- Brain and Spinal Cord Innovative Research Center, Tongji Hospital, Tongji University School of Medicine, Shanghai 200065, China; Key Laboratory of Neuroregeneration of Shanghai Universities, Tongji University School of Medicine, 1239 Siping Road, Room 508, Shanghai 200092, China
| | - Yanhua Du
- Brain and Spinal Cord Innovative Research Center, Tongji Hospital, Tongji University School of Medicine, Shanghai 200065, China; Key Laboratory of Neuroregeneration of Shanghai Universities, Tongji University School of Medicine, 1239 Siping Road, Room 508, Shanghai 200092, China
| | - Zhenyu Chen
- Brain and Spinal Cord Innovative Research Center, Tongji Hospital, Tongji University School of Medicine, Shanghai 200065, China; Key Laboratory of Neuroregeneration of Shanghai Universities, Tongji University School of Medicine, 1239 Siping Road, Room 508, Shanghai 200092, China
| | - Hexi Feng
- Brain and Spinal Cord Innovative Research Center, Tongji Hospital, Tongji University School of Medicine, Shanghai 200065, China; Key Laboratory of Neuroregeneration of Shanghai Universities, Tongji University School of Medicine, 1239 Siping Road, Room 508, Shanghai 200092, China
| | - Shuwei Zhang
- Brain and Spinal Cord Innovative Research Center, Tongji Hospital, Tongji University School of Medicine, Shanghai 200065, China; Key Laboratory of Neuroregeneration of Shanghai Universities, Tongji University School of Medicine, 1239 Siping Road, Room 508, Shanghai 200092, China
| | - Nan Li
- Brain and Spinal Cord Innovative Research Center, Tongji Hospital, Tongji University School of Medicine, Shanghai 200065, China; Key Laboratory of Neuroregeneration of Shanghai Universities, Tongji University School of Medicine, 1239 Siping Road, Room 508, Shanghai 200092, China
| | - Jianren Song
- Brain and Spinal Cord Innovative Research Center, Tongji Hospital, Tongji University School of Medicine, Shanghai 200065, China; Key Laboratory of Reconstruction and Regeneration of Spine and Spinal Cord Injury, Ministry of Education, Shanghai 200065, China
| | - Yujiang Fang
- Brain and Spinal Cord Innovative Research Center, Tongji Hospital, Tongji University School of Medicine, Shanghai 200065, China; Key Laboratory of Neuroregeneration of Shanghai Universities, Tongji University School of Medicine, 1239 Siping Road, Room 508, Shanghai 200092, China
| | - Xiangjie Xu
- Brain and Spinal Cord Innovative Research Center, Tongji Hospital, Tongji University School of Medicine, Shanghai 200065, China; Key Laboratory of Neuroregeneration of Shanghai Universities, Tongji University School of Medicine, 1239 Siping Road, Room 508, Shanghai 200092, China
| | - Lei Shi
- Brain and Spinal Cord Innovative Research Center, Tongji Hospital, Tongji University School of Medicine, Shanghai 200065, China; Key Laboratory of Neuroregeneration of Shanghai Universities, Tongji University School of Medicine, 1239 Siping Road, Room 508, Shanghai 200092, China
| | - Bowen Zhang
- Brain and Spinal Cord Innovative Research Center, Tongji Hospital, Tongji University School of Medicine, Shanghai 200065, China; Key Laboratory of Neuroregeneration of Shanghai Universities, Tongji University School of Medicine, 1239 Siping Road, Room 508, Shanghai 200092, China
| | - Jiayi Cheng
- Brain and Spinal Cord Innovative Research Center, Tongji Hospital, Tongji University School of Medicine, Shanghai 200065, China; Key Laboratory of Neuroregeneration of Shanghai Universities, Tongji University School of Medicine, 1239 Siping Road, Room 508, Shanghai 200092, China
| | - Shanshan Zhou
- Brain and Spinal Cord Innovative Research Center, Tongji Hospital, Tongji University School of Medicine, Shanghai 200065, China; Key Laboratory of Neuroregeneration of Shanghai Universities, Tongji University School of Medicine, 1239 Siping Road, Room 508, Shanghai 200092, China
| | - Ling Liu
- Brain and Spinal Cord Innovative Research Center, Tongji Hospital, Tongji University School of Medicine, Shanghai 200065, China; Key Laboratory of Reconstruction and Regeneration of Spine and Spinal Cord Injury, Ministry of Education, Shanghai 200065, China; Key Laboratory of Neuroregeneration of Shanghai Universities, Tongji University School of Medicine, 1239 Siping Road, Room 508, Shanghai 200092, China
| | - Xiaoqing Zhang
- Brain and Spinal Cord Innovative Research Center, Tongji Hospital, Tongji University School of Medicine, Shanghai 200065, China; Key Laboratory of Reconstruction and Regeneration of Spine and Spinal Cord Injury, Ministry of Education, Shanghai 200065, China; Key Laboratory of Neuroregeneration of Shanghai Universities, Tongji University School of Medicine, 1239 Siping Road, Room 508, Shanghai 200092, China; Tsingtao Advanced Research Institute, Tongji University, Shanghai 200092, China; Shanghai Institute of Stem Cell Research and Clinical Translation, Shanghai 200120, China; Translational Medical Center for Stem Cell Therapy, Shanghai East Hospital, Tongji University School of Medicine, Shanghai 200120, China.
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Plasma dickkopf-related protein 1, an antagonist of the Wnt pathway, is associated with HIV-associated neurocognitive impairment. AIDS 2017; 31:1379-1385. [PMID: 28358733 DOI: 10.1097/qad.0000000000001481] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
OBJECTIVE Dickkopf-related protein 1 (DKK1) is a soluble antagonist of the Wningless (Wnt) pathway. It binds to and sequesters low-density lipoprotein receptor-related proteins 5/6 away from Wnts. Because the Wnt pathway regulates synaptic transmission and plasticity, we hypothesized that increased DKK1 would increase the risk for neurocognitive impairment (NCI) in HIV-positive (HIV) individuals. We evaluated, here, the relationship between plasma DKK1 and global NCI. METHODS Plasma samples and data from 41 HIV to 42 HIV adults were obtained from the University of California, San Diego, California, USA. Concentrations of DKK1 and a comparator protein, monocyte chemoattractant protein-1 (MCP-1), were quantified in plasma by immunoassay. All study participants completed a standardized comprehensive neuropsychological test battery and their performance was summarized using the global deficit score method. RESULTS A higher DKK1 level was associated with NCI among HIV participants (d = 0.63, P = 0.05), particularly among the 26 participants whose plasma HIV RNA level was suppressed (d = 0.74, P = 0.08). DKK1 level was not associated with NCI among HIV participants (P = 0.98). was not associated with NCI in either group. In HIV adults with suppressed plasma HIV RNA, a receiver operator characteristic curve identified that a DKK1 level of at least 735 pg/ml had a positive predictive value of 83.3% for a diagnosis of NCI. This association did not weaken after accounting for the effect of AIDS, nadir CD4 T-cell count, addictive drug use, or demographic characteristics. CONCLUSION DKK1 is a specific biomarker for NCI in HIV adults, implicating the Wnt pathway in HIV neuropathogenesis.
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Noelanders R, Vleminckx K. How Wnt Signaling Builds the Brain: Bridging Development and Disease. Neuroscientist 2016; 23:314-329. [DOI: 10.1177/1073858416667270] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Wnt/β-catenin signaling plays a crucial role throughout all stages of brain development and remains important in the adult brain. Accordingly, many neurological disorders have been linked to Wnt signaling. Defects in Wnt signaling during neural development can give rise to birth defects or lead to neurological dysfunction later in life. Developmental signaling events can also be hijacked in the adult and result in disease. Moreover, knowledge about the physiological role of Wnt signaling in the brain might lead to new therapeutic strategies for neurological diseases. Especially, the important role for Wnt signaling in neural differentiation of pluripotent stem cells has received much attention as this might provide a cure for neurodegenerative disorders. In this review, we summarize the versatile role of Wnt/β-catenin signaling during neural development and discuss some recent studies linking Wnt signaling to neurological disorders.
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Affiliation(s)
- Rivka Noelanders
- Unit of Developmental Biology, Department of Biomedical Molecular Biology, Ghent University, Ghent, Belgium
| | - Kris Vleminckx
- Unit of Developmental Biology, Department of Biomedical Molecular Biology, Ghent University, Ghent, Belgium
- Center for Medical Genetics, Ghent University Hospital, Ghent, Belgium
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Pang L, Dong N, Wang D, Zhang N, Xing J. Increased Dickkopf-1 expression is correlated with poisoning severity in carbon monoxide-poisoned humans and rats. Inhal Toxicol 2016; 28:455-62. [PMID: 27353797 DOI: 10.1080/08958378.2016.1198440] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
CONTEXT Carbon monoxide (CO) poisoning results in neuronal injury. The expression of Dickkopf-1 (DKK-1) has not been investigated previously after CO poisoning. OBJECTIVE The current study aimed to investigate the DKK-1 expression levels in humans and rats with acute CO poisoning and to analyze their correlation with poisoning severity. MATERIALS AND METHODS We measured serum DKK-1 levels in patients with acute CO poisoning (n = 94) and in healthy controls (n = 90). On admission, a poisoning severity score (PSS) was determined for each patient. In addition, 36 male Sprague-Dawley rats were randomly assigned into three groups: (a) Sham group, (b) Low CO group and (c) High CO group. At 2 h after CO poisoning, DKK-1 expression and histopathological damage in the hippocampal tissues were measured. RESULTS Serum DKK-1 levels were significantly higher in the acute CO-poisoned patients, compared to the healthy controls. Serum DKK-1 levels were significantly higher in the CO-poisoned patients with a lower PSS. In rats, CO poisoning induced significant upregulation of the gene and protein expression of DKK-1 in hippocampal tissues. Moreover, there was a positive correlation between DKK-1 levels and the degree of damage in the hippocampal tissues. DISCUSSION DKK-1 induction in neurons after CO poisoning causes further neuronal injury. The severity of acute CO poisoning in rat models is associated with elevated serum DKK-1 levels and its upregulation in the brain tissue. CONCLUSION DKK-1 appears to have potential utility in providing valuable information for determining the severity and damage of CO poisoning.
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Affiliation(s)
- Li Pang
- a Department of Emergency , the First Hospital of Jilin University , Changchun , China
| | - Ning Dong
- a Department of Emergency , the First Hospital of Jilin University , Changchun , China
| | - Dawei Wang
- a Department of Emergency , the First Hospital of Jilin University , Changchun , China
| | - Nan Zhang
- a Department of Emergency , the First Hospital of Jilin University , Changchun , China
| | - Jihong Xing
- a Department of Emergency , the First Hospital of Jilin University , Changchun , China
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Kannan S, Nicola Z, Overall RW, Ichwan M, Ramírez-Rodríguez G, N. Grzyb A, Patone G, Saar K, Hübner N, Kempermann G. Systems Genetics Analysis of a Recombinant Inbred Mouse Cell Culture Panel Reveals Wnt Pathway Member Lrp6 as a Regulator of Adult Hippocampal Precursor Cell Proliferation. Stem Cells 2016; 34:674-84. [DOI: 10.1002/stem.2313] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2015] [Revised: 09/28/2015] [Accepted: 10/25/2015] [Indexed: 11/08/2022]
Affiliation(s)
- Suresh Kannan
- CRTD-Center for Regenerative Therapies Dresden; Technische Universität Dresden; Dresden Germany
- Department of Biomedical Sciences; Sri Ramachandra University; Porur Chennai India
| | - Zeina Nicola
- German Center for Neurodegenerative Diseases (DZNE) Dresden; Dresden Germany
| | - Rupert W. Overall
- CRTD-Center for Regenerative Therapies Dresden; Technische Universität Dresden; Dresden Germany
| | - Muhammad Ichwan
- CRTD-Center for Regenerative Therapies Dresden; Technische Universität Dresden; Dresden Germany
| | - Gerardo Ramírez-Rodríguez
- Laboratory of Neurogenesis, Division of Clinical Investigations; National Institute of Psychiatry “Ramón de la Fuente Muñiz; ” México D.F. México
| | - Anna N. Grzyb
- German Center for Neurodegenerative Diseases (DZNE) Dresden; Dresden Germany
| | | | - Kathrin Saar
- Max-Delbrück Center for Molecular Medicine; Berlin Germany
| | - Norbert Hübner
- Max-Delbrück Center for Molecular Medicine; Berlin Germany
| | - Gerd Kempermann
- CRTD-Center for Regenerative Therapies Dresden; Technische Universität Dresden; Dresden Germany
- German Center for Neurodegenerative Diseases (DZNE) Dresden; Dresden Germany
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Decoding the ubiquitous role of microRNAs in neurogenesis. Mol Neurobiol 2016; 54:2003-2011. [PMID: 26910816 DOI: 10.1007/s12035-016-9797-2] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2015] [Accepted: 02/16/2016] [Indexed: 12/21/2022]
Abstract
Neurogenesis generates fledgling neurons that mature to form an intricate neuronal circuitry. The delusion on adult neurogenesis was far resolved in the past decade and became one of the largely explored domains to identify multifaceted mechanisms bridging neurodevelopment and neuropathology. Neurogenesis encompasses multiple processes including neural stem cell proliferation, neuronal differentiation, and cell fate determination. Each neurogenic process is specifically governed by manifold signaling pathways, several growth factors, coding, and non-coding RNAs. A class of small non-coding RNAs, microRNAs (miRNAs), is ubiquitously expressed in the brain and has emerged to be potent regulators of neurogenesis. It functions by fine-tuning the expression of specific neurogenic gene targets at the post-transcriptional level and modulates the development of mature neurons from neural progenitor cells. Besides the commonly discussed intrinsic factors, the neuronal morphogenesis is also under the control of several extrinsic temporal cues, which in turn are regulated by miRNAs. This review enlightens on dicer controlled switch from neurogenesis to gliogenesis, miRNA regulation of neuronal maturation and the differential expression of miRNAs in response to various extrinsic cues affecting neurogenesis.
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Lhx2 regulates the timing of β-catenin-dependent cortical neurogenesis. Proc Natl Acad Sci U S A 2015; 112:12199-204. [PMID: 26371318 DOI: 10.1073/pnas.1507145112] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
The timing of cortical neurogenesis has a major effect on the size and organization of the mature cortex. The deletion of the LIM-homeodomain transcription factor Lhx2 in cortical progenitors by Nestin-cre leads to a dramatically smaller cortex. Here we report that Lhx2 regulates the cortex size by maintaining the cortical progenitor proliferation and delaying the initiation of neurogenesis. The loss of Lhx2 in cortical progenitors results in precocious radial glia differentiation and a temporal shift of cortical neurogenesis. We further investigated the underlying mechanisms at play and demonstrated that in the absence of Lhx2, the Wnt/β-catenin pathway failed to maintain progenitor proliferation. We developed and applied a mathematical model that reveals how precocious neurogenesis affected cortical surface and thickness. Thus, we concluded that Lhx2 is required for β-catenin function in maintaining cortical progenitor proliferation and controls the timing of cortical neurogenesis.
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Zhang Z, Wang H, Jin Z, Cai X, Gao N, Cui X, Liu P, Zhang J, Yang S, Yang X. Downregulation of survivin regulates adult hippocampal neurogenesis and apoptosis, and inhibits spatial learning and memory following traumatic brain injury. Neuroscience 2015; 300:219-28. [PMID: 25987205 DOI: 10.1016/j.neuroscience.2015.05.025] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2015] [Revised: 05/09/2015] [Accepted: 05/11/2015] [Indexed: 10/23/2022]
Abstract
Survivin, a unique member of the inhibitor of the apoptosis protein (IAP) family, has been suggested to play a crucial role in promoting the cell cycle and mediates mitosis during embryonic development. However, the role of survivin following traumatic brain injury (TBI) in adult neurogenesis and apoptosis in the mouse dentate gyrus (DG) remains only partially understood. We adopted adenovirus-mediated RNA interference (RNAi) as a means of suppressing the expression of survivin and observed its effects on adult regeneration and neurological function in mice after brain injury. The mice were subjected to TBI, and the ipsilateral hippocampus was then examined using reverse transcription polymerase chain reaction (RT-PCR) and Western blotting analyses. Brain slices were stained for 5'-bromo-2'-deoxyuridine (BrdU) and doublecortin (DCX). Our data showed that survivin knockdown inhibits the proliferation and differentiation of neural precursor cells (NPCs) in the DG of the hippocampus soon after TBI. Furthermore, downregulation of survivin results in a significant increase in programmed cell death in the DG, as assessed using terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) and 4',6-diamidino-2-phenylindole (DAPI) double staining. The Morris water maze (MWM) test was adopted to evaluate neurological function, which confirmed that knockdown of survivin worsened the memory capacity that was already compromised following TBI. Survivin in adult mice brains after TBI can be successfully down-regulated by RNAi, which inhibited adult hippocampal neurogenesis, promoted apoptotic cell death, and resulted in a negative role in the recovery of dysfunction following injury.
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Affiliation(s)
- Z Zhang
- Department of Neurosurgery, Tianjin Medical University General Hospital, Tianjin 300052, PR China; Tianjin Neurological Institute, Tianjin Key Laboratory of Injuries, Variations and Regeneration of Nervous System, 154 Anshan Road, Heping District, Tianjin 300052, PR China
| | - H Wang
- Department of Neurosurgery, Tianjin Medical University General Hospital, Tianjin 300052, PR China; Tianjin Neurological Institute, Tianjin Key Laboratory of Injuries, Variations and Regeneration of Nervous System, 154 Anshan Road, Heping District, Tianjin 300052, PR China
| | - Z Jin
- Department of Neurosurgery, Tianjin Medical University General Hospital, Tianjin 300052, PR China; Tianjin Neurological Institute, Tianjin Key Laboratory of Injuries, Variations and Regeneration of Nervous System, 154 Anshan Road, Heping District, Tianjin 300052, PR China
| | - X Cai
- Department of Neurosurgery, Tianjin Medical University General Hospital, Tianjin 300052, PR China; Tianjin Neurological Institute, Tianjin Key Laboratory of Injuries, Variations and Regeneration of Nervous System, 154 Anshan Road, Heping District, Tianjin 300052, PR China
| | - N Gao
- Department of Neurosurgery, Tianjin Medical University General Hospital, Tianjin 300052, PR China; Tianjin Neurological Institute, Tianjin Key Laboratory of Injuries, Variations and Regeneration of Nervous System, 154 Anshan Road, Heping District, Tianjin 300052, PR China
| | - X Cui
- Department of Neurosurgery, Tianjin Medical University General Hospital, Tianjin 300052, PR China; Tianjin Neurological Institute, Tianjin Key Laboratory of Injuries, Variations and Regeneration of Nervous System, 154 Anshan Road, Heping District, Tianjin 300052, PR China
| | - P Liu
- Department of Neurosurgery, Tianjin Medical University General Hospital, Tianjin 300052, PR China; Tianjin Neurological Institute, Tianjin Key Laboratory of Injuries, Variations and Regeneration of Nervous System, 154 Anshan Road, Heping District, Tianjin 300052, PR China
| | - J Zhang
- Department of Neurosurgery, Tianjin Medical University General Hospital, Tianjin 300052, PR China; Tianjin Neurological Institute, Tianjin Key Laboratory of Injuries, Variations and Regeneration of Nervous System, 154 Anshan Road, Heping District, Tianjin 300052, PR China
| | - S Yang
- Department of Neurosurgery, Tianjin Medical University General Hospital, Tianjin 300052, PR China; Tianjin Neurological Institute, Tianjin Key Laboratory of Injuries, Variations and Regeneration of Nervous System, 154 Anshan Road, Heping District, Tianjin 300052, PR China
| | - X Yang
- Department of Neurosurgery, Tianjin Medical University General Hospital, Tianjin 300052, PR China; Tianjin Neurological Institute, Tianjin Key Laboratory of Injuries, Variations and Regeneration of Nervous System, 154 Anshan Road, Heping District, Tianjin 300052, PR China.
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15
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Sugiyama T, Osumi N, Katsuyama Y. A novel cell migratory zone in the developing hippocampal formation. J Comp Neurol 2014; 522:3520-38. [PMID: 24771490 DOI: 10.1002/cne.23621] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2014] [Revised: 04/25/2014] [Accepted: 04/25/2014] [Indexed: 11/08/2022]
Abstract
The hippocampal formation (HF) is a unique structure in the mammalian brain and is subdivided into the dentate gyrus, Ammon's horn, and subiculum by their functions and connectivity in the neuronal circuit. Because behaviors of the neural stem cells, neuronal progenitors, and the differentiating neurons are complex during hippocampal morphogenesis, the differentiation of these subdivisions has not been well understood. In this study, we investigated embryonic and postnatal expression of the proteins Prox1, Math2, and Ctip2, which clearly indicate principal cells of the dentate gyrus (Prox1 positive) and Ammon's horn (Math2 and Ctip2 positive). Expression patterns of Prox1 and Math2 were consistent with previously suggested localization of migratory pathways of the dentate granule cells and hippocampal pyramidal cells. Interestingly, we found intermingling of Prox1-expressing cells and Math2-expressing cells in a cell migratory stream, suggesting previously unknown behaviors of differentiating cells of the HF.
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Affiliation(s)
- Taku Sugiyama
- Department of Developmental Neuroscience, Tohoku University Graduate School of Medicine, Sendai, 980-8575, Japan
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16
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Bielen H, Houart C. The Wnt cries many: Wnt regulation of neurogenesis through tissue patterning, proliferation, and asymmetric cell division. Dev Neurobiol 2014; 74:772-80. [DOI: 10.1002/dneu.22168] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2013] [Revised: 11/23/2013] [Accepted: 01/28/2014] [Indexed: 01/09/2023]
Affiliation(s)
- Holger Bielen
- MRC Centre for Developmental Neurobiology; King's College London, Guy's Campus; London SE1 1UL United Kingdom
| | - Corinne Houart
- MRC Centre for Developmental Neurobiology; King's College London, Guy's Campus; London SE1 1UL United Kingdom
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17
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Ortiz-Matamoros A, Salcedo-Tello P, Avila-Muñoz E, Zepeda A, Arias C. Role of wnt signaling in the control of adult hippocampal functioning in health and disease: therapeutic implications. Curr Neuropharmacol 2014; 11:465-76. [PMID: 24403870 PMCID: PMC3763754 DOI: 10.2174/1570159x11311050001] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2012] [Revised: 03/16/2013] [Accepted: 03/16/2013] [Indexed: 12/12/2022] Open
Abstract
It is well recognized the role of the Wnt pathway in many developmental processes such as neuronal maturation, migration, neuronal connectivity and synaptic formation. Growing evidence is also demonstrating its function in the mature brain where is associated with modulation of axonal remodeling, dendrite outgrowth, synaptic activity, neurogenesis and behavioral plasticity. Proteins involved in Wnt signaling have been found expressed in the adult hippocampus suggesting that Wnt pathway plays a role in the hippocampal function through life. Indeed, Wnt ligands act locally to regulate neurogenesis, neuronal cell shape and pre- and postsynaptic assembly, events that are thought to underlie changes in synaptic function associated with long-term potentiation and with cognitive tasks such as learning and memory. Recent data have demonstrated the increased expression of the Wnt antagonist Dickkopf-1 (DKK1) in brains of Alzheimer´s disease (AD) patients suggesting that dysfunction of Wnt signaling could also contribute to AD pathology. We review here evidence of Wnt-associated molecules expression linked to physiological and pathological hippocampal functioning in the adult brain. The basic aspects of Wnt related mechanisms underlying hippocampal plasticity as well as evidence of how hippocampal dysfunction may rely on Wnt dysregulation is analyzed. This information would provide some clues about the possible therapeutic targets for developing treatments for neurodegenerative diseases associated with aberrant brain plasticity.
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Affiliation(s)
- Abril Ortiz-Matamoros
- Departamento de Medicina Genómica y Toxicología Ambiental, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, México D.F
| | - Pamela Salcedo-Tello
- Departamento de Medicina Genómica y Toxicología Ambiental, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, México D.F
| | - Evangelina Avila-Muñoz
- Departamento de Medicina Genómica y Toxicología Ambiental, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, México D.F
| | - Angélica Zepeda
- Departamento de Medicina Genómica y Toxicología Ambiental, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, México D.F
| | - Clorinda Arias
- Departamento de Medicina Genómica y Toxicología Ambiental, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, México D.F
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18
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Wu D, Murashov AK. MicroRNA-431 regulates axon regeneration in mature sensory neurons by targeting the Wnt antagonist Kremen1. Front Mol Neurosci 2013; 6:35. [PMID: 24167472 PMCID: PMC3807041 DOI: 10.3389/fnmol.2013.00035] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2013] [Accepted: 10/03/2013] [Indexed: 11/13/2022] Open
Abstract
MicroRNAs (miRNAs) are small, non-coding RNAs that function as key post-transcriptional regulators in neural development, brain function, and neurological diseases. Growing evidence indicates that miRNAs are also important mediators of nerve regeneration, however, the affected signaling mechanisms are not clearly understood. In the present study, we show that nerve injury-induced miR-431 stimulates regenerative axon growth by silencing Kremen1, an antagonist of Wnt/beta-catenin signaling. Both the gain-of-function of miR-431 and knockdown of Kremen1 significantly enhance axon outgrowth in murine dorsal root ganglion neuronal cultures. Using cross-linking with AGO-2 immunoprecipitation, and 3'-untranslated region (UTR) luciferase reporter assay we demonstrate miR-431 direct interaction on the 3'-UTR of Kremen1 mRNA. Together, our results identify miR-431 as an important regulator of axonal regeneration and a promising therapeutic target.
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Affiliation(s)
- Di Wu
- Department of Neurobiology and Anatomy, Drexel University College of Medicine Philadelphia, PA, USA
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19
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Seib DRM, Corsini NS, Ellwanger K, Plaas C, Mateos A, Pitzer C, Niehrs C, Celikel T, Martin-Villalba A. Loss of Dickkopf-1 restores neurogenesis in old age and counteracts cognitive decline. Cell Stem Cell 2013; 12:204-14. [PMID: 23395445 DOI: 10.1016/j.stem.2012.11.010] [Citation(s) in RCA: 223] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2012] [Revised: 09/11/2012] [Accepted: 11/15/2012] [Indexed: 12/19/2022]
Abstract
Memory impairment has been associated with age-related decline in adult hippocampal neurogenesis. Although Notch, bone morphogenetic protein, and Wnt signaling pathways are known to regulate multiple aspects of adult neural stem cell function, the molecular basis of declining neurogenesis in the aging hippocampus remains unknown. Here, we show that expression of the Wnt antagonist Dickkopf-1 (Dkk1) increases with age and that its loss enhances neurogenesis in the hippocampus. Neural progenitors with inducible loss of Dkk1 increase their Wnt activity, which leads to enhanced self-renewal and increased generation of immature neurons. This Wnt-expanded progeny subsequently matures into glutamatergic granule neurons with increased dendritic complexity. As a result, mice deficient in Dkk1 exhibit enhanced spatial working memory and memory consolidation and also show improvements in affective behavior. Taken together, our findings show that upregulating Wnt signaling by reducing Dkk1 expression can counteract age-related decrease in neurogenesis and its associated cognitive decline.
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Affiliation(s)
- Désirée R M Seib
- Division of Molecular Neurobiology, DKFZ-ZMBH Alliance, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg, Germany
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20
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Nielsen JV, Thomassen M, Møllgård K, Noraberg J, Jensen NA. Zbtb20 defines a hippocampal neuronal identity through direct repression of genes that control projection neuron development in the isocortex. ACTA ACUST UNITED AC 2013; 24:1216-29. [PMID: 23283686 DOI: 10.1093/cercor/bhs400] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Hippocampal pyramidal neurons are important for encoding and retrieval of spatial maps and episodic memories. While previous work has shown that Zbtb20 is a cell fate determinant for CA1 pyramidal neurons, the regulatory mechanisms governing this process are not known. In this study, we demonstrate that Zbtb20 binds to genes that control neuronal subtype specification in the developing isocortex, including Cux1, Cux2, Fezf2, Foxp2, Mef2c, Rorb, Satb2, Sox5, Tbr1, Tle4, and Zfpm2. We show that Zbtb20 represses these genes during ectopic CA1 pyramidal neuron development in transgenic mice. These data reveal a novel regulatory mechanism by which Zbtb20 suppresses the acquisition of an isocortical fate during archicortical neurogenesis to ensure commitment to a CA1 pyramidal neuron fate. We further show that the expression pattern of Zbtb20 is evolutionary conserved in the fetal human hippocampus, where it is complementary to the expression pattern of the Zbtb20 target gene Tbr1. Therefore, the disclosed Zbtb20-mediated transcriptional repressor mechanism may be involved in development of the human archicortex.
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Affiliation(s)
- Jakob V Nielsen
- Department of Neurobiology Research, Institute of Molecular Medicine, University of Southern Denmark, DK-5000 Odense C, Denmark
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21
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Signalling through the type 1 insulin-like growth factor receptor (IGF1R) interacts with canonical Wnt signalling to promote neural proliferation in developing brain. ASN Neuro 2012; 4:AN20120009. [PMID: 22625652 PMCID: PMC3392751 DOI: 10.1042/an20120009] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Signalling through the IGF1R [type 1 IGF (insulin-like growth factor) receptor] and canonical Wnt signalling are two signalling pathways that play critical roles in regulating neural cell generation and growth. To determine whether the signalling through the IGF1R can interact with the canonical Wnt signalling pathway in neural cells in vivo, we studied mutant mice with altered IGF signalling. We found that in mice with blunted IGF1R expression specifically in nestin-expressing neural cells (IGF1RNestin−KO mice) the abundance of neural β-catenin was significantly reduced. Blunting IGF1R expression also markedly decreased: (i) the activity of a LacZ (β-galactosidase) reporter transgene that responds to Wnt nuclear signalling (LacZTCF reporter transgene) and (ii) the number of proliferating neural precursors. In contrast, overexpressing IGF-I (insulin-like growth factor I) in brain markedly increased the activity of the LacZTCF reporter transgene. Consistently, IGF-I treatment also markedly increased the activity of the LacZTCF reporter transgene in embryonic neuron cultures that are derived from LacZTCF Tg (transgenic) mice. Importantly, increasing the abundance of β-catenin in IGF1RNestin−KO embryonic brains by suppressing the activity of GSK3β (glycogen synthase kinase-3β) significantly alleviated the phenotypic changes induced by IGF1R deficiency. These phenotypic changes includes: (i) retarded brain growth, (ii) reduced precursor proliferation and (iii) decreased neuronal number. Our current data, consistent with our previous study of cultured oligodendrocytes, strongly support the concept that IGF signalling interacts with canonical Wnt signalling in the developing brain to promote neural proliferation. The interaction of IGF and canonical Wnt signalling plays an important role in normal brain development by promoting neural precursor proliferation.
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22
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Abstract
The Wnt/β-catenin pathway promotes proliferation of neural progenitor cells (NPCs) at early stages and induces neuronal differentiation from NPCs at late stages, but the molecular mechanisms that control this stage-specific response are unclear. Pin1 is a prolyl isomerase that regulates cell signaling uniquely by controlling protein conformation after phosphorylation, but its role in neuronal differentiation is not known. Here we found that whereas Pin1 depletion suppresses neuronal differentiation, Pin1 overexpression enhances it, without any effects on gliogenesis from NPCs in vitro. Consequently, Pin1-null mice have significantly fewer upper layer neurons in the motor cortex and severely impaired motor activity during the neonatal stage. A proteomic approach identified β-catenin as a major substrate for Pin1 in NPCs, in which Pin1 stabilizes β-catenin. As a result, Pin1 knockout leads to reduced β-catenin during differentiation but not proliferation of NPCs in developing brains. Importantly, defective neuronal differentiation in Pin1 knockout NPCs is fully rescued in vitro by overexpression of β-catenin but not a β-catenin mutant that fails to act as a Pin1 substrate. These results show that Pin1 is a novel regulator of NPC differentiation by acting on β-catenin and provides a new postphosphorylation signaling mechanism to regulate developmental stage-specific functioning of β-catenin signaling in neuronal differentiation.
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23
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Fotaki V, Price DJ, Mason JO. Wnt/β-catenin signaling is disrupted in the extra-toes (Gli3(Xt/Xt) ) mutant from early stages of forebrain development, concomitant with anterior neural plate patterning defects. J Comp Neurol 2012; 519:1640-57. [PMID: 21452227 DOI: 10.1002/cne.22592] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
The zinc finger transcription factor Gli3 is essential for normal development of the forebrain. Mutant mice with no functional Gli3 (extra-toes, Gli3(Xt/Xt) mutants) display a massive reduction in the size of the telencephalic lobes and absence of dorsomedial telencephalic structures, including the cortical hem, which normally expresses a number of Wnt molecules essential for patterning the hippocampus. Dorsomedial telencephalic Wnt activity, transduced through the Wnt/β-catenin signaling pathway, is also required for hippocampal specification and dorsoventral telencephalic patterning. Wnts whose normal expression is restricted to the cortical hem are completely absent in Gli3(Xt/Xt) embryos, but some expression of those Wnts with a broader expression domain persists, raising the possibility that Wnt/β-catenin signaling may still be active in this mutant. We examined whether the Wnt expression that persists in the Gli3(Xt/Xt) mutant neocortex activates Wnt/β-catenin signaling, using the BAT-gal transgenic reporter. We found Wnt/β-catenin signaling consistently decreased in the forebrains of Gli3(Xt/Xt) mutants, even prior to the formation of the cortical hem. This is accompanied by a severe reduction in expression of Wnt7b and Wnt8b at the lateral edges of the anterior neural plate that will give rise to the pallium. In addition, we found a significant increase in the expression of rostroventral markers of the anterior neural plate that will give rise to the basal forebrain. Our data reveal that Gli3 is required at the neural plate stage to regulate Wnt expression and Wnt/β-catenin signaling in the presumptive forebrain and confirm its previously proposed role in patterning the anterior neural plate.
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Affiliation(s)
- Vassiliki Fotaki
- Genes and Development Group, Centre for Integrative Physiology, School of Biomedical Sciences, University of Edinburgh, Edinburgh EH8 9XD, United Kingdom.
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24
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Solberg N, Machon O, Machonova O, Krauss S. Mouse Tcf3 represses canonical Wnt signaling by either competing for β-catenin binding or through occupation of DNA-binding sites. Mol Cell Biochem 2012; 365:53-63. [PMID: 22270545 DOI: 10.1007/s11010-012-1243-9] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2011] [Accepted: 01/14/2012] [Indexed: 12/11/2022]
Abstract
Tcf3 acts as a transcription factor controlling gene expression in canonical Wnt signaling. In this study we show that mouse Tcf3 represses canonical Wnt signaling in mouse neural stem cells and in human HEK 293 cells. We demonstrate that mouse Tcf3 mediates repression of both moderate and high levels of canonical Wnt signaling, by either competing with other members of the Tcf/Lef family for binding to β-catenin, or for binding to DNA. We observed that the repressor activity of mouse Tcf3 was only relieved effectively upon simultaneous disruption of both mechanisms. Immunofluorescence of transfected HEK 293 cells showed co-localization of β-catenin and Tcf3 in the nucleus of cells transfected with full-length Tcf3, but not in cells transfected with N-terminal deleted versions. A direct physical interaction between β-catenin and Tcf3 in the nucleus was confirmed by co-immunoprecipitation studies. The inhibitory β-catenin/Tcf3 interface was independent of the ability of Tcf3 to directly interact with DNA.
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Affiliation(s)
- Nina Solberg
- SFI-CAST Biomedical Innovation Center, Unit for Cell Signaling, Oslo University Hospital, Forskningsparken, Gaustadalleén 21, 0349 Oslo, Norway.
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25
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Moors M, Bose R, Johansson-Haque K, Edoff K, Okret S, Ceccatelli S. Dickkopf 1 mediates glucocorticoid-induced changes in human neural progenitor cell proliferation and differentiation. Toxicol Sci 2011; 125:488-95. [PMID: 22048647 DOI: 10.1093/toxsci/kfr304] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Glucocorticoids (GC) are critical for normal development of the fetal brain, and alterations in their levels can induce neurotoxicity with detrimental consequences. Still, there is little information available on the effects of GC on human neural stem/progenitor cells (hNPC). In the present study, we have investigated the effects of the synthetic GC dexamethasone (Dex) on hNPC grown as neurospheres, with special focus on their proliferation and differentiation capacity and the underlying molecular mechanisms. Immunocytochemical stainings showed that Dex markedly decreases proliferation and neuronal differentiation while promoting glia cell formation. Analysis of pathway-specific genes revealed that Dex induces an upregulation of the Wnt-signaling antagonist DKK1. Moreover, Dex- or DKK1-treated hNPCs showed reduced transcriptional levels of the two canonical Wnt target genes cyclin D1 and inhibitor of DNA binding 2 (ID2). Chromatin immunoprecipitation showed that Dex, via the glucocorticoid receptor, interacts with the DKK1 promotor. Treatment of hNPC with recombinant DKK1 or neutralizing antibodies indicated that DKK1 has a critical role in the Dex-induced inhibition of proliferation and neuronal differentiation with a concomitant increase in glial cells. Taken together, our findings show that GC reduce proliferation and interfere with differentiation of hNPCs via the canonical Wnt-signaling pathway.
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Affiliation(s)
- Michaela Moors
- Department of Neuroscience, Karolinska Institutet, 17177 Stockholm, Sweden
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26
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Misztal K, Wisniewska MB, Ambrozkiewicz M, Nagalski A, Kuznicki J. WNT protein-independent constitutive nuclear localization of beta-catenin protein and its low degradation rate in thalamic neurons. J Biol Chem 2011; 286:31781-8. [PMID: 21757747 DOI: 10.1074/jbc.m111.229666] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Nuclear localization of β-catenin is a hallmark of canonical Wnt signaling, a pathway that plays a crucial role in brain development and the neurogenesis of the adult brain. We recently showed that β-catenin accumulates specifically in mature thalamic neurons, where it regulates the expression of the Ca(v)3.1 voltage-gated calcium channel gene. Here, we investigated the mechanisms underlying β-catenin accumulation in thalamic neurons. We report that a lack of soluble factors produced either by glia or cortical neurons does not impair nuclear β-catenin accumulation in thalamic neurons. We next found that the number of thalamic neurons with β-catenin nuclear localization did not change when the Wnt/Dishevelled signaling pathway was inhibited by Dickkopf1 or a dominant negative mutant of Dishevelled3. These results suggest a WNT-independent cell-autonomous mechanism. We found that the protein levels of APC, AXIN1, and GSK3β, components of the β-catenin degradation complex, were lower in the thalamus than in the cortex of the adult rat brain. Reduced levels of these proteins were also observed in cultured thalamic neurons compared with cortical cultures. Finally, pulse-chase experiments confirmed that cytoplasmic β-catenin turnover was slower in thalamic neurons than in cortical neurons. Altogether, our data indicate that the nuclear localization of β-catenin in thalamic neurons is their cell-intrinsic feature, which was WNT-independent but associated with low levels of proteins involved in β-catenin labeling for ubiquitination and subsequent degradation.
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Affiliation(s)
- Katarzyna Misztal
- Laboratory of Neurodegeneration, International Institute of Molecular and Cell Biology, 4 Ks. Trojdena Street, 02-109 Warsaw, Poland
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27
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Molecular and cellular mechanisms contributing to the regulation, proliferation and differentiation of neural stem cells in the adult dentate gyrus. Keio J Med 2011; 59:79-83. [PMID: 20881448 DOI: 10.2302/kjm.59.79] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Adult neural stem cells (NSCs) are a potential endogenous source for neuronal cell replacement in the diseased adult central nervous system (CNS). However, the recruitment of adult NSCs for repair is hampered by the current lack of knowledge about the cellular and molecular mechanisms that control their behavior in vivo. We have previously demonstrated that environment-derived signals control the fate choice of adult NSCs. More recently we have provided evidence that in the adult hippocampal dentate gyrus - one of the two neurogenic regions of the adult CNS - specialized astrocytes provide signals that instruct NSCs to adopt a neuronal fate. In this review I will examine in vitro and in vivo the molecular mechanisms underlying the neuronal fate instruction of adult NSCs by the local astrocyte population in the adult hippocampus. In particular, I will focus on the Wnt family of proteins, which we have found to be expressed in adult hippocampal astrocytes; our preliminary studies have also shown that these proteins enhance the generation of neurons from adult NSCs in vitro.
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28
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Zoeller RT. Endocrine Disruption of the Thyroid and its Consequences in Development. RESEARCH AND PERSPECTIVES IN ENDOCRINE INTERACTIONS 2011. [DOI: 10.1007/978-3-642-22775-2_4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
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29
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Zhang L, Yang X, Yang S, Zhang J. The Wnt /β-catenin signaling pathway in the adult neurogenesis. Eur J Neurosci 2010; 33:1-8. [PMID: 21073552 DOI: 10.1111/j.1460-9568.2010.7483.x] [Citation(s) in RCA: 105] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The Wnt/β-catenin signaling pathway plays an important role in neural development, β-catenin is a central component of the Wnt/β-catenin signaling pathway, which not only performs the function of transmitting information in the cytoplasm, but also translocates to the nucleus-activating target gene transcription. The target genes in neural tissues have not been fully revealed, but the effects of the Wnt/β-catenin signaling pathway in adult neurogenesis have been demonstrated by ongoing research, which are significative to the basic research and treatment of neuronal degeneration diseases. Here, we review key findings to show the characteristics of β-catenin and its pivotal nature in the Wnt/β-catenin signaling pathway in a number of molecular studies. We also review current literature on the role of β-catenin in adult neurogenesis, which consists of an active process encompassing the proliferation, migration, differentiation and final synaptogenesis.
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Affiliation(s)
- Lin Zhang
- Department of Neurosurgery, Tianjin Medical University General Hospital, Tianjin Key Laboratory of Injuries,Variations and Regeneration of Nervous System, Tianjin, China
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30
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Pinnock SB, Blake AM, Platt NJ, Herbert J. The roles of BDNF, pCREB and Wnt3a in the latent period preceding activation of progenitor cell mitosis in the adult dentate gyrus by fluoxetine. PLoS One 2010; 5:e13652. [PMID: 21048974 PMCID: PMC2965105 DOI: 10.1371/journal.pone.0013652] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2010] [Accepted: 10/04/2010] [Indexed: 02/04/2023] Open
Abstract
The formation of new neurons continues into adult life in the dentate gyrus of the rat hippocampus, as in many other species. Neurogenesis itself turns out to be highly labile, and is regulated by a number of factors. One of these is the serotoninergic system: treatment with drugs (such as the SSRI fluoxetine) markedly stimulates mitosis in the progenitor cells of the dentate gyrus. But this process has one remarkable feature: it takes at least 14 days of continuous treatment to be effective. This is despite the fact that the pharmacological action of fluoxetine occurs within an hour or so of first administration. This paper explores the role of BDNF in this process, using the effect of a Trk antagonist (K252a) on the labelling of progenitor cells with the mitosis marker Ki67 and the associated expression of pCREB and Wnt3a. These experiments show that (i) Fluoxetine increased Ki67 counts, as well as pCREB and Wnt3a expression in the dentate gyrus. The action of fluoxetine on the progenitor cells and on pCREB (but not Wnt3a) depends upon Trk receptor activation, since it was prevented by icv infusion of K252a. (ii) These receptors are required for both the first 7 days of fluoxetine action, during which no apparent change in progenitor mitosis occurs, as well as the second 7 days. Increased pCREB was always associated with progenitor cell mitosis, but Wnt3a expression may be necessary but not sufficient for increased progenitor cell proliferation. These results shed new light on the action of fluoxetine on neurogenesis in the adult dentate gyrus, and have both clinical and experimental interest.
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Affiliation(s)
- Scarlett B Pinnock
- Department of Physiology, Cambridge Centre for Brain Repair, University of Cambridge, Cambridge, United Kingdom
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Fotaki V, Larralde O, Zeng S, McLaughlin D, Nichols J, Price DJ, Theil T, Mason JO. Loss of Wnt8b has no overt effect on hippocampus development but leads to altered Wnt gene expression levels in dorsomedial telencephalon. Dev Dyn 2010; 239:284-296. [PMID: 19890917 DOI: 10.1002/dvdy.22137] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Wnt signalling proteins regulate many aspects of animal development. We have investigated the function of mouse Wnt8b during forebrain development. Wnt8b is expressed in a highly restricted pattern including the prospective hippocampus and hypothalamus. Mutant mice lacking Wnt8b are viable and healthy. The size and morphology of the hippocampus appeared normal in mutant embryos and adults, and we found no evidence of hypothalamic defects in mutants. Wnt8b is also expressed in the neurogenic region of the adult dentate gyrus, however, cell proliferation was unchanged in Wnt8b(-/-) mutants. Mutant embryos did, however, display altered levels of expression of other Wnt genes normally expressed in forebrain. The spatial expression patterns of other Wnt genes and the overall level of canonical Wnt activity were indistinguishable from wild-types. Thus, loss of Wnt8b does not give rise to an overt morphological phenotype, but does affect expression levels of other Wnts in developing forebrain.
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Affiliation(s)
- Vassiliki Fotaki
- Genes and Development Group, Centre for Integrative Physiology, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh EH8 9XD, UK
| | - Osmany Larralde
- Genes and Development Group, Centre for Integrative Physiology, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh EH8 9XD, UK
| | - Shaoju Zeng
- Genes and Development Group, Centre for Integrative Physiology, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh EH8 9XD, UK
- Key Laboratory for Cell Proliferation and Regulation Biology, Beijing Normal University, China
| | - David McLaughlin
- Genes and Development Group, Centre for Integrative Physiology, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh EH8 9XD, UK
| | - Jennifer Nichols
- Institute for Stem Cell Research, University of Edinburgh, King's Buildings, Edinburgh EH9 3JQ, UK
| | - David J Price
- Genes and Development Group, Centre for Integrative Physiology, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh EH8 9XD, UK
| | - Thomas Theil
- Genes and Development Group, Centre for Integrative Physiology, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh EH8 9XD, UK
| | - John O Mason
- Genes and Development Group, Centre for Integrative Physiology, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh EH8 9XD, UK
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Ulloa F, Martí E. Wnt won the war: antagonistic role of Wnt over Shh controls dorso-ventral patterning of the vertebrate neural tube. Dev Dyn 2010; 239:69-76. [PMID: 19681160 DOI: 10.1002/dvdy.22058] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
The spinal cord has been used as a model to dissect the mechanisms that govern the patterning of tissues during animal development, since the principles that rule the dorso-ventral patterning of the neural tube are applicable to other systems. Signals that determine the dorso-ventral axis of the spinal cord include Sonic hedgehog (Shh), acting as a bona fide morphogenetic signal to determine ventral progenitor identities, and members of the Bmp and the Wnt families, acting in the dorsal neural tube. Although Wnts have been initially recognized as important in proliferation of neural progenitor cells, their role in the dorso-ventral patterning has been controversial. In this review, we discuss recent reports that show an important contribution of the Wnt canonical pathway in dorso-ventral pattern formation. These data allow building a model by which the ventralizing activity of Shh is antagonized by Wnt activity through the expression of Gli3, a potent inhibitor of the Shh pathway. Therefore, antagonistic interactions between canonical Wnt, promoting dorsal identities, and Shh pathways, inducing ventral ones, would define the dorso-ventral patterning of the developing central nervous system.
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Affiliation(s)
- Fausto Ulloa
- Institute for Research in Biomedicine, Parc Cientific de Barcelona; Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Department of Cell Biology, University of Barcelona, Barcelona, Spain
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Quinlan R, Graf M, Mason I, Lumsden A, Kiecker C. Complex and dynamic patterns of Wnt pathway gene expression in the developing chick forebrain. Neural Dev 2009; 4:35. [PMID: 19732418 PMCID: PMC2757023 DOI: 10.1186/1749-8104-4-35] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2009] [Accepted: 09/04/2009] [Indexed: 01/07/2023] Open
Abstract
Background Wnt signalling regulates multiple aspects of brain development in vertebrate embryos. A large number of Wnts are expressed in the embryonic forebrain; however, it is poorly understood which specific Wnt performs which function and how they interact. Wnts are able to activate different intracellular pathways, but which of these pathways become activated in different brain subdivisions also remains enigmatic. Results We have compiled the first comprehensive spatiotemporal atlas of Wnt pathway gene expression at critical stages of forebrain regionalisation in the chick embryo and found that most of these genes are expressed in strikingly dynamic and complex patterns. Several expression domains do not respect proposed compartment boundaries in the developing forebrain, suggesting that areal identities are more dynamic than previously thought. Using an in ovo electroporation approach, we show that Wnt4 expression in the thalamus is negatively regulated by Sonic hedgehog (Shh) signalling from the zona limitans intrathalamica (ZLI), a known organising centre of forebrain development. Conclusion The forebrain is exposed to a multitude of Wnts and Wnt inhibitors that are expressed in a highly dynamic and complex fashion, precluding simple correlative conclusions about their respective functions or signalling mechanisms. In various biological systems, Wnts are antagonised by Shh signalling. By demonstrating that Wnt4 expression in the thalamus is repressed by Shh from the ZLI we reveal an additional level of interaction between these two pathways and provide an example for the cross-regulation between patterning centres during forebrain regionalisation.
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Affiliation(s)
- Robyn Quinlan
- MRC Centre for Developmental Neurobiology, New Hunt's House, Guy's Hospital Campus, King's College, London SE1 1UL, UK.
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Kuwabara T, Hsieh J, Muotri A, Yeo G, Warashina M, Lie DC, Moore L, Nakashima K, Asashima M, Gage FH. Wnt-mediated activation of NeuroD1 and retro-elements during adult neurogenesis. Nat Neurosci 2009; 12:1097-105. [PMID: 19701198 DOI: 10.1038/nn.2360] [Citation(s) in RCA: 474] [Impact Index Per Article: 31.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2009] [Accepted: 05/22/2009] [Indexed: 01/15/2023]
Abstract
In adult hippocampus, new neurons are continuously generated from neural stem cells (NSCs), but the molecular mechanisms regulating adult neurogenesis remain elusive. We found that Wnt signaling, together with the removal of Sox2, triggered the expression of NeuroD1 in mice. This transcriptional regulatory mechanism was dependent on a DNA element containing overlapping Sox2 and T-cell factor/lymphoid enhancer factor (TCF/LEF)-binding sites (Sox/LEF) in the promoter. Notably, Sox/LEF sites were also found in long interspersed nuclear element 1 (LINE-1) elements, consistent with their critical roles in the transition of NSCs to proliferating neuronal progenitors. Our results describe a previously unknown Wnt-mediated regulatory mechanism that simultaneously coordinates activation of NeuroD1 and LINE-1, which is important for adult neurogenesis and survival of neuronal progenitors. Moreover, the discovery that LINE-1 retro-elements embedded in the mammalian genome can function as bi-directional promoters suggests that Sox/LEF regulatory sites may represent a general mechanism, at least in part, for relaying environmental signals to other nearby loci to promote adult hippocampal neurogenesis.
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Affiliation(s)
- Tomoko Kuwabara
- National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba Science City, Japan.
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Wang X, Lee JE, Dorsky RI. Identification of Wnt-responsive cells in the zebrafish hypothalamus. Zebrafish 2009; 6:49-58. [PMID: 19374548 DOI: 10.1089/zeb.2008.0570] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
In all vertebrate brains, there is a period of widespread embryonic neurogenesis followed by specific regional neurogenesis that continues into adult stages. The Wnt signaling pathway, which is essential for numerous developmental processes, has also been suggested to be involved in neurogenesis. To help investigate the exact roles of canonical Wnt signaling in neurogenesis, here we examine the identity of Wnt-responsive cells in the zebrafish hypothalamus. This tissue is a useful diencephalic neurogenesis model containing evolutionarily conserved populations of neurons. We first performed in situ hybridization to show the expression patterns of Tcf family members and a canonical Wnt signaling reporter in the 50 hpf embryonic hypothalamus and larval/adult hypothalamus. We then used immunohistochemistry to identify the cell types of Wnt-responsive and Lef1-positive cells in both 50 hpf embryonic and adult hypothalamus. Our results indicate that Wnt-responsive cells in the hypothalamus are likely to be both mitotic progenitors and postmitotic precursors at embryonic stages, but only precursors at the adult stage. These data suggest that canonical Wnt signaling may be functionally required for maintenance of neural progenitor and precursor pools in the embryo, and for ongoing neurogenesis in the adult zebrafish.
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Affiliation(s)
- Xu Wang
- Department of Neurobiology and Anatomy, University of Utah, Salt Lake City, Utah 84132, USA
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Beta-catenin-mediated Wnt signaling regulates neurogenesis in the ventral telencephalon. Nat Neurosci 2008; 11:1383-91. [PMID: 18997789 DOI: 10.1038/nn.2226] [Citation(s) in RCA: 98] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2008] [Accepted: 10/14/2008] [Indexed: 12/29/2022]
Abstract
Development of the telencephalon involves the coordinated growth of diversely patterned brain structures. Previous studies have demonstrated the importance of beta-catenin-mediated Wnt signaling in proliferation and fate determination during cerebral cortical development. We found that beta-catenin-mediated Wnt signaling critically maintained progenitor proliferation in the subcortical (pallidal) telencephalon. Targeted deletion of beta-catenin in mice severely impaired proliferation in the medial ganglionic eminence without grossly altering differentiated fate. Several lines of evidence suggest that this phenotype is primarily the result of a loss of canonical Wnt signaling. As previous studies have suggested that the ventral patterning factor Sonic Hedgehog (Shh) also stimulates dorsal telencephalic proliferation, we propose a model whereby Wnt and Shh signaling promote distinct dorsal-ventral patterning while also having broader effects on proliferation that serve to coordinate the growth of telencephalic subregions.
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