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Kamal Z, Ebnalwaled AA, Al-Amgad Z, Saied AA, Metwally AA, Said AH. The Nephroprotective Effect of In Utero Administration of Green Synthesized Titanium Dioxide Nanoparticles in Albino Rats. Biol Trace Elem Res 2024; 202:3686-3700. [PMID: 37968492 DOI: 10.1007/s12011-023-03940-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/05/2023] [Accepted: 10/25/2023] [Indexed: 11/17/2023]
Abstract
Titanium dioxide nanoparticles (TiO2-NPs) are one of the most popular nanoscale materials and have a wide range of applications in the manufacturing industry; nonetheless, researchers' focus has been directed to the detrimental consequences of TiO2-NPs. The current study was designed to assess the potential hazardous effects of chemically synthesized TiO2-NPs on the placenta and feto-maternal kidneys of rats. On the other hand, the probable positive impact of TiO2-NPs made after green synthesis was also evaluated. HepG2 cell lines were used to assess the cytotoxicity of chemical and green TiO2-NPs. Five groups of fifty pregnant female rats were formed (n=10). The first (control) group received distilled water. The second and third groups were orally given 100 and 300 mg/kg body weight (bw) of chemical TiO2-NPs, respectively. The fourth and fifth groups were orally given 100 and 300 mg/kg bw of green synthesized TiO2-NPs, respectively. On gestational day 20 (GD 20), blood and tissues were collected for biochemical and histological studies. Our findings revealed that chemical TiO2-NPs induced apoptosis in HepG2 cells at high concentrations, while there was no observed toxicity for green TiO2-NPs. The chemically treated TiO2-NPs groups showed a significant decrease in the level of HDL and a significant increase in cholesterol, LDL-cholesterol, and triglyceride levels. Renal tissues showed necrosis with exfoliation of lining epithelial cells, degenerated tubules, and glomerulonephritis. While the placenta was atrophied and hyalinized. Moreover, Bax expression significantly increased in the renal tubular cells and the villi of the placenta. Contrariwise, green TiO2-NPs-treated groups showed a significant rise in HDL levels with a significant reduction in triglycerides and LDL levels, while cholesterol levels were unaffected. Also, renal tissues showed mild degenerative changes in the glomeruli and renal tubules; thus, noticeable regeneration of epithelium lining tubules was detected in the maternal kidney. Bax showed a minimal reaction in the renal tubules and the villi of the placenta. It concluded that in contrast to chemical TiO2-NPs, biosynthesized TiO2-NPs with garlic showed a positive impact on the biochemical profile and histological investigations.
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Affiliation(s)
- Zeinab Kamal
- Zoology Department, Faculty of Science, South Valley University, Qena, 83523, Egypt
| | - A A Ebnalwaled
- Electronic and Nano Devises Lab, Faculty of Science, South Valley University, Qena, 83523, Egypt
| | - Zeinab Al-Amgad
- General Authority for Veterinary Services, Qena Veterinary Directorate, Qena, 83523, Egypt
| | | | - Asmaa A Metwally
- Department of Surgery, Anesthesiology, and Radiology, Faculty of Veterinary Medicine, Aswan University, Aswan, 81528, Egypt.
| | - Alaa H Said
- Electronic and Nano Devises Lab, Faculty of Science, South Valley University, Qena, 83523, Egypt
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Mignan T, Pumarola M, Platt S, James M, Pereira M, Morey‐Matamalas A, Recio A. Granuloprival cerebellar cortical degeneration in a Yorkshire Terrier and Lagotto Romagnolo dog. J Vet Intern Med 2024; 38:2368-2372. [PMID: 38662636 PMCID: PMC11256161 DOI: 10.1111/jvim.17091] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2024] [Accepted: 04/12/2024] [Indexed: 07/19/2024] Open
Abstract
Granuloprival degeneration is an uncommon form of cerebellar cortical degeneration (CCD). A 3-month-old Yorkshire Terrier and a 7-month-old Lagotto Romagnolo dog were presented with a history of progressive cerebellar dysfunction including wide-based stance, cerebellar ataxia, intention tremors, and loss of menace response despite normal vision. Magnetic resonance imaging of the brain identified marked diffuse decrease of the cerebellum size. Euthanasia was performed in both cases because of progression of clinical signs. Histopathological examination identified marked diffuse thinning of the granular cell layer with almost complete loss of the granular cell neurons, providing a definitive diagnosis of granuloprival CCD. Granuloprival CCD should be considered as a differential diagnosis in Yorkshire Terrier and Lagotto Romagnolo dogs with post-natal progressive clinical signs of cerebellar dysfunction.
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Affiliation(s)
- Thomas Mignan
- Dovecote Veterinary Hospital, 5 Delven Lane, Castle DoningtonDerby DE74 2LJUnited Kingdom
| | - Martí Pumarola
- Department of Animal Medicine and Surgery, Veterinary FacultyUniversitat Autònoma de Barcelona, Bellaterra (Cerdanyola del Vallès)Barcelona 08193Spain
| | - Simon Platt
- CVS Teleneurology, 1 Owen RoadDiss IP22 4ERUnited Kingdom
| | - Matthew James
- Dovecote Veterinary Hospital, 5 Delven Lane, Castle DoningtonDerby DE74 2LJUnited Kingdom
| | - Marta Pereira
- School of Veterinary Medicine and Science, University of NottinghamSutton Bonington, Leicestershire LE12 5RDUnited Kingdom
| | - Antonia Morey‐Matamalas
- School of Veterinary Medicine and Science, University of NottinghamSutton Bonington, Leicestershire LE12 5RDUnited Kingdom
| | - Alfredo Recio
- Clínica Veterinaria Levante, Avenida de La Unión 61San Javier, Murcia 30730Spain
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Gupta I, Yeung J, Rahimi-Balaei M, Wu SR, Goldowitz D. Msx genes delineate a novel molecular map of the developing cerebellar neuroepithelium. Front Mol Neurosci 2024; 17:1356544. [PMID: 38742226 PMCID: PMC11089253 DOI: 10.3389/fnmol.2024.1356544] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2023] [Accepted: 04/12/2024] [Indexed: 05/16/2024] Open
Abstract
In the early cerebellar primordium, there are two progenitor zones, the ventricular zone (VZ) residing atop the IVth ventricle and the rhombic lip (RL) at the lateral edges of the developing cerebellum. These zones give rise to the several cell types that form the GABAergic and glutamatergic populations of the adult cerebellum, respectively. Recently, an understanding of the molecular compartmentation of these zones has emerged. To add to this knowledge base, we report on the Msx genes, a family of three transcription factors, that are expressed downstream of Bone Morphogenetic Protein (BMP) signaling in these zones. Using fluorescent RNA in situ hybridization, we have characterized the Msx (Msh Homeobox) genes and demonstrated that their spatiotemporal pattern segregates specific regions within the progenitor zones. Msx1 and Msx2 are compartmentalized within the rhombic lip (RL), while Msx3 is localized within the ventricular zone (VZ). The relationship of the Msx genes with an early marker of the glutamatergic lineage, Atoh1, was examined in Atoh1-null mice and it was found that the expression of Msx genes persisted. Importantly, the spatial expression of Msx1 and Msx3 altered in response to the elimination of Atoh1. These results point to the Msx genes as novel early markers of cerebellar progenitor zones and more importantly to an updated view of the molecular parcellation of the RL with respect to the canonical marker of the RL, Atoh1.
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Affiliation(s)
- Ishita Gupta
- British Columbia Children’s Hospital, Vancouver, BC, Canada
- Department of Medical Genetics, University of British Columbia, Vancouver, BC, Canada
| | - Joanna Yeung
- British Columbia Children’s Hospital, Vancouver, BC, Canada
- Department of Medical Genetics, University of British Columbia, Vancouver, BC, Canada
| | - Maryam Rahimi-Balaei
- British Columbia Children’s Hospital, Vancouver, BC, Canada
- Department of Medical Genetics, University of British Columbia, Vancouver, BC, Canada
| | - Sih-Rong Wu
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, United States
| | - Dan Goldowitz
- British Columbia Children’s Hospital, Vancouver, BC, Canada
- Department of Medical Genetics, University of British Columbia, Vancouver, BC, Canada
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Kamal Z, Said AH, Ebnalwaled AA, Rehan IF, Zigo F, Farkašová Z, Allam M. Genetic effects of chemically and biosynthesized titanium dioxide nanoparticles in vitro and in vivo of female rats and their fetuses. Front Vet Sci 2023; 10:1142305. [PMID: 37614463 PMCID: PMC10442826 DOI: 10.3389/fvets.2023.1142305] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2023] [Accepted: 07/13/2023] [Indexed: 08/25/2023] Open
Abstract
With the increase in nanoparticles (NPs) products on the market, the possibility of animal and human exposure to these materials will increase. The smaller size of NPs facilitates their entrance through placental barriers and allows them to accumulate in embryonic tissue, where they can then be a source of different developmental malformations. Several toxicity studies with chemically synthesized titanium dioxide NPs (CTiO2 NPs) have been recently carried out; although there is insufficient data on exposure to biosynthesized titanium dioxide NPs (BTiO2 NPs) during pregnancy, the study aimed to evaluate the ability of an eco-friendly biosynthesis technique using garlic extract against maternal and fetal genotoxicities, which could result from repeated exposure to TiO2 NPs during gestation days (GD) 6-19. A total of fifty pregnant rats were divided into five groups (n = 10) and gavaged CTiO2 NPs and BTiO2 NPs at 100 and 300 mg/kg/day concentrations. Pregnant rats on GD 20 were anesthetized, uterine horns were removed, and then embryotoxicity was performed. The kidneys of the mothers and fetuses in each group were collected and then maintained in a frozen condition. Our results showed that garlic extract can be used as a reducing agent for the formation of TiO2 NPs. Moreover, BTiO2 NPs showed less toxic potential than CTiO2 NPs in HepG2 cells. Both chemically and biosynthesized TiO2 NP-induced genetic variation in the 16S rRNA sequences of mother groups compared to the control group. In conclusion, the genetic effects of the 16S rRNA sequence induced by chemically synthesized TiO2 NPs were greater than those of biosynthesized TiO2 NPs. However, there were no differences between the control group and the embryo-treated groups with chemically and biologically synthesized TiO2 NPs.
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Affiliation(s)
- Zeinab Kamal
- Department of Zoology, Faculty of Science, South Valley University, Qena, Egypt
| | - Alaa H. Said
- Electronic and Nano Devises Lab, Faculty of Science, South Valley University, Qena, Egypt
| | - A. A. Ebnalwaled
- Electronic and Nano Devises Lab, Faculty of Science, South Valley University, Qena, Egypt
| | - Ibrahim F. Rehan
- Department of Husbandry and Development of Animal Wealth, Faculty of Veterinary Medicine, Menoufia University, Shebin Alkom, Egypt
- Department of Pathobiochemistry, Faculty of Pharmacy, Meijo University, Nagoya, Aichi, Japan
| | - František Zigo
- Department of Nutrition and Animal Husbandry, University of Veterinary Medicine and Pharmacy in Košice, Košice, Slovakia
| | - Zuzana Farkašová
- Department of Nutrition and Animal Husbandry, University of Veterinary Medicine and Pharmacy in Košice, Košice, Slovakia
| | - Mohammad Allam
- Department of Zoology, Faculty of Science, Luxor University, Luxor, Egypt
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Ismail OI, Shaltout ES, Abdellah NZ, Hetta DF, Abd El-Ghani WMA, Abdelzaher LA, Mahmoud AMM, Hasan AM, Rashed NA, Ebrahem NE. The teratogenic effect of pregabalin on heart, liver and kidney in rats: a light microscopic, electron microscopic and immunohistochemical study. BMC Pharmacol Toxicol 2022; 23:4. [PMID: 34986900 PMCID: PMC8734350 DOI: 10.1186/s40360-021-00546-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2021] [Accepted: 12/22/2021] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Pregabalin (PGB) was approved as new anti-epileptic drugs with little information about its teratogenic effect. AIM OF THE WORK to evaluate the developmental toxicity of PGB. MATERIALS AND METHODS 60 pregnant albino rats were divided into three groups. PGB (500 mg/kg body weight/day) was given to group II, PGB (1250 mg/kg body weight/day) was given to Group III and no medications were given to group I. The pups were normally delivered. Liver, kidney and heart specimens were prepared for histological, immunohistochemical, and morphometric studies. RESULTS A dose of 500 mg of PGB had minimal toxic effects in the form of mild collagen deposition and moderate positive caspase-3 immunoexpression. PGB dose of 1250 mg/kg induced gross toxic effects in form of degenerated cardiac myofibres, ruptured blood vessels, vacuolations in the renal cortex, fibrosis and strong positive caspase-3 immunoexpression. CONCLUSION PGB at dose of 500 mg/kg revealed minimal toxic changes. PGB cause embryotoxicity in a dose-dependent manner, as the higher dose induced more degenerative changes.
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Affiliation(s)
- Omnia I. Ismail
- Department of Human Anatomy and Embryology, Faculty of Medicine, Assiut University, Assiut, 71515 Egypt
| | - Eman S. Shaltout
- Department of Forensic Medicine & Clinical Toxicology, Faculty of Medicine, Assiut University, Assiut, 71515 Egypt
| | - Nora Z. Abdellah
- Department of Forensic Medicine & Clinical Toxicology, Faculty of Medicine, Assiut University, Assiut, 71515 Egypt
| | - Diab F. Hetta
- Department of Anesthesia and Pain Management, South East Institute, Assiut University, Assiut, 71515 Egypt
| | | | - Lobna A. Abdelzaher
- Department of Pharmacology, Faculty of Medicine, Assiut University, Assiut, 71515 Egypt
| | | | - Asmaa M. Hasan
- Department of Neuropsychiatry, Assiut University hospital, Assiut, 71515 Egypt
| | - Noha A. Rashed
- Department of Human Anatomy and Embryology, Faculty of Medicine, Assiut University, Assiut, 71515 Egypt
| | - Noha Esmael Ebrahem
- Department of Forensic Medicine & Clinical Toxicology, Faculty of Medicine, Assiut University, Assiut, 71515 Egypt
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Jensen GS, Leon-Palmer NE, Townsend KL. Bone morphogenetic proteins (BMPs) in the central regulation of energy balance and adult neural plasticity. Metabolism 2021; 123:154837. [PMID: 34331962 DOI: 10.1016/j.metabol.2021.154837] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Revised: 06/28/2021] [Accepted: 07/19/2021] [Indexed: 12/14/2022]
Abstract
The current worldwide obesity pandemic highlights a need to better understand the regulation of energy balance and metabolism, including the role of the nervous system in controlling energy intake and energy expenditure. Neural plasticity in the hypothalamus of the adult brain has been implicated in full-body metabolic health, however, the mechanisms surrounding hypothalamic plasticity are incompletely understood. Bone morphogenetic proteins (BMPs) control metabolic health through actions in the brain as well as in peripheral tissues such as adipose, together regulating both energy intake and energy expenditure. BMP ligands, receptors, and inhibitors are found throughout plastic adult brain regions and have been demonstrated to modulate neurogenesis and gliogenesis, as well as synaptic and dendritic plasticity. This role for BMPs in adult neural plasticity is distinct from their roles in brain development. Existing evidence suggests that BMPs induce weight loss through hypothalamic pathways, and part of the mechanism of action may be through inducing neural plasticity. In this review, we summarize the data regarding how BMPs affect neural plasticity in the adult mammalian brain, as well as the relationship between central BMP signaling and metabolic health.
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Affiliation(s)
- Gabriel S Jensen
- Graduate School of Biomedical Science and Engineering, University of Maine, Orono, ME, United States of America; Department of Neurological Surgery, The Ohio State University Wexner Medical Center, Columbus, OH, United States of America
| | - Noelle E Leon-Palmer
- School of Biology and Ecology, University of Maine, Orono, ME, United States of America
| | - Kristy L Townsend
- Graduate School of Biomedical Science and Engineering, University of Maine, Orono, ME, United States of America; Department of Neurological Surgery, The Ohio State University Wexner Medical Center, Columbus, OH, United States of America; School of Biology and Ecology, University of Maine, Orono, ME, United States of America.
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7
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Consalez GG, Goldowitz D, Casoni F, Hawkes R. Origins, Development, and Compartmentation of the Granule Cells of the Cerebellum. Front Neural Circuits 2021; 14:611841. [PMID: 33519389 PMCID: PMC7843939 DOI: 10.3389/fncir.2020.611841] [Citation(s) in RCA: 83] [Impact Index Per Article: 27.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Accepted: 12/17/2020] [Indexed: 12/21/2022] Open
Abstract
Granule cells (GCs) are the most numerous cell type in the cerebellum and indeed, in the brain: at least 99% of all cerebellar neurons are granule cells. In this review article, we first consider the formation of the upper rhombic lip, from which all granule cell precursors arise, and the way by which the upper rhombic lip generates the external granular layer, a secondary germinal epithelium that serves to amplify the upper rhombic lip precursors. Next, we review the mechanisms by which postmitotic granule cells are generated in the external granular layer and migrate radially to settle in the granular layer. In addition, we review the evidence that far from being a homogeneous population, granule cells come in multiple phenotypes with distinct topographical distributions and consider ways in which the heterogeneity of granule cells might arise during development.
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Affiliation(s)
- G Giacomo Consalez
- Division of Neuroscience, San Raffaele Scientific Institute, San Raffaele University, Milan, Italy
| | - Daniel Goldowitz
- Department of Medical Genetics, Centre for Molecular Medicine and Therapeutics, University of British Columbia, Vancouver, BC, Canada
| | - Filippo Casoni
- Division of Neuroscience, San Raffaele Scientific Institute, San Raffaele University, Milan, Italy
| | - Richard Hawkes
- Department of Cell Biology and Anatomy, Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
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Macrì S, Di-Poï N. Heterochronic Developmental Shifts Underlying Squamate Cerebellar Diversity Unveil the Key Features of Amniote Cerebellogenesis. Front Cell Dev Biol 2020; 8:593377. [PMID: 33195265 PMCID: PMC7642464 DOI: 10.3389/fcell.2020.593377] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Accepted: 09/25/2020] [Indexed: 11/13/2022] Open
Abstract
Despite a remarkable conservation of architecture and function, the cerebellum of vertebrates shows extensive variation in morphology, size, and foliation pattern. These features make this brain subdivision a powerful model to investigate the evolutionary developmental mechanisms underlying neuroanatomical complexity both within and between anamniote and amniote species. Here, we fill a major evolutionary gap by characterizing the developing cerebellum in two non-avian reptile species-bearded dragon lizard and African house snake-representative of extreme cerebellar morphologies and neuronal arrangement patterns found in squamates. Our data suggest that developmental strategies regarded as exclusive hallmark of birds and mammals, including transit amplification in an external granule layer (EGL) and Sonic hedgehog expression by underlying Purkinje cells (PCs), contribute to squamate cerebellogenesis independently from foliation pattern. Furthermore, direct comparison of our models suggests the key importance of spatiotemporal patterning and dynamic interaction between granule cells and PCs in defining cortical organization. Especially, the observed heterochronic shifts in early cerebellogenesis events, including upper rhombic lip progenitor activity and EGL maintenance, are strongly expected to affect the dynamics of molecular interaction between neuronal cell types in snakes. Altogether, these findings help clarifying some of the morphogenetic and molecular underpinnings of amniote cerebellar corticogenesis, but also suggest new potential molecular mechanisms underlying cerebellar complexity in squamates. Furthermore, squamate models analyzed here are revealed as key animal models to further understand mechanisms of brain organization.
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Affiliation(s)
- Simone Macrì
- Program in Developmental Biology, Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| | - Nicolas Di-Poï
- Program in Developmental Biology, Institute of Biotechnology, University of Helsinki, Helsinki, Finland
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Qin L, Ahn KJ, Wine Lee L, de Charleroy C, Crenshaw EB. Analyses with double knockouts of the Bmpr1a and Bmpr1b genes demonstrate that BMP signaling is involved in the formation of precerebellar mossy fiber nuclei derived from the rhombic lip. PLoS One 2019; 14:e0226602. [PMID: 31869353 PMCID: PMC6927620 DOI: 10.1371/journal.pone.0226602] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2018] [Accepted: 12/01/2019] [Indexed: 11/25/2022] Open
Abstract
Bone morphogenetic proteins (BMPs) have been hypothesized to specify distinct dorsal neural fates. During neural development, BMPs are expressed in the roof plate and adjacent neuroepithelium. Because several hindbrain nuclei that form the proprioceptive/vestibular/auditory sensory network originate from the rhombic lip, near the roof plate, BMP signaling may regulate the development of these nuclei. To test this hypothesis genetically, we have examined the development of the hindbrain in BMP type I receptor knockout mice. Our results demonstrate that BMP signaling is involved in the formation of precerebellar mossy fiber nuclei, which give rise to cerebellar mossy fibers, but is not required for the development of the inferior olivary nucleus, which gives rise to cerebellar climbing fibers.
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Affiliation(s)
- Lihua Qin
- Division of Pediatric Otolaryngology, Mammalian Neurogenetics Group, Center for Childhood Communication, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, United States of America
- Department of Anatomy and Histoembryology, School of Basic Medical Sciences, Peking University Health Science Center, Beijing, China
| | - Kyung J. Ahn
- Division of Pediatric Otolaryngology, Mammalian Neurogenetics Group, Center for Childhood Communication, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, United States of America
| | - Lara Wine Lee
- Division of Pediatric Otolaryngology, Mammalian Neurogenetics Group, Center for Childhood Communication, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, United States of America
- Neuroscience Graduate Group, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, United States of America
| | - Charles de Charleroy
- Division of Pediatric Otolaryngology, Mammalian Neurogenetics Group, Center for Childhood Communication, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, United States of America
| | - E. Bryan Crenshaw
- Division of Pediatric Otolaryngology, Mammalian Neurogenetics Group, Center for Childhood Communication, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, United States of America
- Neuroscience Graduate Group, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, United States of America
- Department of Otorhinolaryngology, Head and Neck Surgery, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, United States of America
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Cha HL, Choi JM, Oh HH, Bashyal N, Kim SS, Birnbaumer L, Suh-Kim H. Deletion of the α subunit of the heterotrimeric Go protein impairs cerebellar cortical development in mice. Mol Brain 2019; 12:57. [PMID: 31221179 PMCID: PMC6585000 DOI: 10.1186/s13041-019-0477-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2019] [Accepted: 05/29/2019] [Indexed: 02/02/2023] Open
Abstract
Go is a member of the pertussis toxin-sensitive Gi/o family. Despite its abundance in the central nervous system, the precise role of Go remains largely unknown compared to other G proteins. In the present study, we explored the functions of Go in the developing cerebellar cortex by deleting its gene, Gnao. We performed a histological analysis with cerebellar sections of adult mice by cresyl violet- and immunostaining. Global deletion of Gnao induced cerebellar hypoplasia, reduced arborization of Purkinje cell dendrites, and atrophied Purkinje cell dendritic spines and the terminal boutons of climbing fibers from the inferior olivary nucleus. These results indicate that Go-mediated signaling pathway regulates maturation of presynaptic parallel fibers from granule cells and climbing fibers during the cerebellar cortical development.
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Affiliation(s)
- Hye Lim Cha
- Departments of Anatomy, Ajou University School of Medicine, Woldcup-ro 164, Yeongtong-gu, Suwon, 16499 South Korea
| | - Jung-Mi Choi
- Departments of Anatomy, Ajou University School of Medicine, Woldcup-ro 164, Yeongtong-gu, Suwon, 16499 South Korea
| | - Huy-Hyen Oh
- Departments of Anatomy, Ajou University School of Medicine, Woldcup-ro 164, Yeongtong-gu, Suwon, 16499 South Korea
| | - Narayan Bashyal
- Departments of Anatomy, Ajou University School of Medicine, Woldcup-ro 164, Yeongtong-gu, Suwon, 16499 South Korea
- Departments of Biomedical Sciences, The Graduate School, Ajou University School of Medicine, World cup-ro 164, Yeongtong-gu, Suwon, 16499 South Korea
| | - Sung-Soo Kim
- Departments of Anatomy, Ajou University School of Medicine, Woldcup-ro 164, Yeongtong-gu, Suwon, 16499 South Korea
| | - Lutz Birnbaumer
- Neurobiology Laboratory, National Institute of Environmental Health Sciences, Research Triangle Park, Durham, 27709 NC USA
- Institute of Biomedical Research (BIOMED), School of Medical Sciences, Catholic University of Argentina, Av. Alicia Moreau de Justo 1300, Edificio San Jose Piso 3, C1107AAZ Buenos Aires, Argentina
| | - Haeyoung Suh-Kim
- Departments of Anatomy, Ajou University School of Medicine, Woldcup-ro 164, Yeongtong-gu, Suwon, 16499 South Korea
- Departments of Biomedical Sciences, The Graduate School, Ajou University School of Medicine, World cup-ro 164, Yeongtong-gu, Suwon, 16499 South Korea
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11
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Meis1 Coordinates Cerebellar Granule Cell Development by Regulating Pax6 Transcription, BMP Signaling and Atoh1 Degradation. J Neurosci 2018; 38:1277-1294. [PMID: 29317485 DOI: 10.1523/jneurosci.1545-17.2017] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2017] [Revised: 12/12/2017] [Accepted: 12/19/2017] [Indexed: 11/21/2022] Open
Abstract
Cerebellar granule cell precursors (GCPs) and granule cells (GCs) represent good models to study neuronal development. Here, we report that the transcription factor myeloid ectopic viral integration site 1 homolog (Meis1) plays pivotal roles in the regulation of mouse GC development. We found that Meis1 is expressed in GC lineage cells and astrocytes in the cerebellum during development. Targeted disruption of the Meis1 gene specifically in the GC lineage resulted in smaller cerebella with disorganized lobules. Knock-down/knock-out (KO) experiments for Meis1 and in vitro assays showed that Meis1 binds to an upstream sequence of Pax6 to enhance its transcription in GCPs/GCs and also suggested that the Meis1-Pax6 cascade regulates morphology of GCPs/GCs during development. In the conditional KO (cKO) cerebella, many Atoh1-positive GCPs were observed ectopically in the inner external granule layer (EGL) and a similar phenomenon was observed in cultured cerebellar slices treated with a bone morphogenic protein (BMP) inhibitor. Furthermore, expression of Smad proteins and Smad phosphorylation were severely reduced in the cKO cerebella and Meis1-knock-down GCPs cerebella. Reduction of phosphorylated Smad was also observed in cerebellar slices electroporated with a Pax6 knock-down vector. Because it is known that BMP signaling induces Atoh1 degradation in GCPs, these findings suggest that the Meis1-Pax6 pathway increases the expression of Smad proteins to upregulate BMP signaling, leading to degradation of Atoh1 in the inner EGL, which contributes to differentiation from GCPs to GCs. Therefore, this work reveals crucial functions of Meis1 in GC development and gives insights into the general understanding of the molecular machinery underlying neural differentiation from neural progenitors.SIGNIFICANCE STATEMENT We report that myeloid ectopic viral integration site 1 homolog (Meis1) plays pivotal roles in the regulation of mouse granule cell (GC) development. Here, we show Meis1 is expressed in GC precursors (GCPs) and GCs during development. Our knock-down and conditional knock-out (cKO) experiments and in vitro assays revealed that Meis1 is required for proper cerebellar structure formation and for Pax6 transcription in GCPs and GCs. The Meis1-Pax6 cascade regulates the morphology of GCs. In the cKO cerebella, Smad proteins and bone morphogenic protein (BMP) signaling are severely reduced and Atoh1-expressing GCPs are ectopically detected in the inner external granule layer. These findings suggest that Meis1 regulates degradation of Atoh1 via BMP signaling, contributing to GC differentiation in the inner EGL, and should provide understanding into GC development.
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Cerebellar networks and neuropathology of cerebellar developmental disorders. HANDBOOK OF CLINICAL NEUROLOGY 2018; 154:109-128. [PMID: 29903435 DOI: 10.1016/b978-0-444-63956-1.00007-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The cerebellar system is a series of axonal projections and synaptic circuits as networks, similar to those of the limbic system and those subserving the propagation and spread of seizures. Three principal cerebellar networks are identified and cerebellar disease often affects components of the networks other than just the cerebellar cortex. Contemporary developmental neuropathology of the cerebellum is best considered in the context of alterations of developmental processes: embryonic segmentation and genetic gradients along the three axes of the neural tube, individual neuronal and glial cell differentiation, migration, synaptogenesis, and myelination. Precisely timed developmental processes may be delayed or precocious rhombencephalosynapsis and pontocerebellar hypoplasia exemplify opposite gradients in the horizontal axis. Chiari II malformation may be reconsidered as a disorder of segmentation rather than simply due to mechanical forces upon normally developing hindbrain structures. Cellular nodules in the roof of the fourth ventricle are heterotopia of histologically differentiated but architecturally disoriented and disorganized neurons and glial cells; they often are less mature immunocytochemically than similar cells in adjacent normal folia. Cell rests are nodules of undifferentiated neuroepithelial cells. Both are frequent in human fetuses and neonates. Axonal projections from heterotopia to adjacent cerebellar folia or nuclei are few or absent, hence these nodules are clinically silent despite neuronal differentiation.
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Meyers EA, Kessler JA. TGF-β Family Signaling in Neural and Neuronal Differentiation, Development, and Function. Cold Spring Harb Perspect Biol 2017; 9:cshperspect.a022244. [PMID: 28130363 DOI: 10.1101/cshperspect.a022244] [Citation(s) in RCA: 104] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Signaling by the transforming growth factor β (TGF-β) family is necessary for proper neural development and function throughout life. Sequential waves of activation, inhibition, and reactivation of TGF-β family members regulate numerous elements of the nervous system from the earliest stages of embryogenesis through adulthood. This review discusses the expression, regulation, and function of TGF-β family members in the central nervous system at various developmental stages, beginning with induction and patterning of the nervous system to their importance in the adult as modulators of inflammatory response and involvement in degenerative diseases.
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Affiliation(s)
- Emily A Meyers
- Department of Neurology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois 60611
| | - John A Kessler
- Department of Neurology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois 60611
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Rosin JM, McAllister BB, Dyck RH, Percival CJ, Kurrasch DM, Cobb J. Mice lacking the transcription factor SHOX2 display impaired cerebellar development and deficits in motor coordination. Dev Biol 2015; 399:54-67. [DOI: 10.1016/j.ydbio.2014.12.013] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2014] [Revised: 12/05/2014] [Accepted: 12/10/2014] [Indexed: 01/06/2023]
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Tong KK, Ma TC, Kwan KM. BMP/Smad signaling and embryonic cerebellum development: Stem cell specification and heterogeneity of anterior rhombic lip. Dev Growth Differ 2015; 57:121-34. [DOI: 10.1111/dgd.12198] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2014] [Revised: 12/15/2014] [Accepted: 01/05/2015] [Indexed: 01/16/2023]
Affiliation(s)
- Ka Kui Tong
- School of Life Sciences; The Chinese University of Hong Kong; Hong Kong China
| | - Tsz Ching Ma
- School of Life Sciences; The Chinese University of Hong Kong; Hong Kong China
| | - Kin Ming Kwan
- School of Life Sciences; The Chinese University of Hong Kong; Hong Kong China
- RGC-AoE Centre for Organelle Biogenesis and Function; The Chinese University of Hong Kong; Hong Kong China
- Partner State Key Laboratory of Agrobiotechnology (CUHK); The Chinese University of Hong Kong; Hong Kong China
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Roles for the TGFβ superfamily in the development and survival of midbrain dopaminergic neurons. Mol Neurobiol 2014; 50:559-73. [PMID: 24504901 DOI: 10.1007/s12035-014-8639-3] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2013] [Accepted: 01/02/2014] [Indexed: 12/29/2022]
Abstract
The adult midbrain contains 75% of all dopaminergic neurons in the CNS. Within the midbrain, these neurons are divided into three anatomically and functionally distinct clusters termed A8, A9 and A10. The A9 group plays a functionally non-redundant role in the control of voluntary movement, which is highlighted by the motor syndrome that results from their progressive degeneration in the neurodegenerative disorder, Parkinson's disease. Despite 50 years of investigation, treatment for Parkinson's disease remains symptomatic, but an intensive research effort has proposed delivering neurotrophic factors to the brain to protect the remaining dopaminergic neurons, or using these neurotrophic factors to differentiate dopaminergic neurons from stem cell sources for cell transplantation. Most neurotrophic factors studied in this context have been members of the transforming growth factor β (TGFβ) superfamily. In recent years, an intensive research effort has focused on understanding the function of these proteins in midbrain dopaminergic neuron development and their role in the molecular architecture that regulates the development of this brain region, with the goal of applying this knowledge to develop novel therapies for Parkinson's disease. In this review, the current evidence showing that TGFβ superfamily members play critical roles in the regulation of midbrain dopaminergic neuron induction, differentiation, target innervation and survival during embryonic and postnatal development is analysed, and the implications of these findings are discussed.
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Affiliation(s)
| | - Richard Hawkes
- Department of Cell Biology and Anatomy, Genes and Development Research Group and Hotchkiss Brain Institute, Faculty of Medicine, University of Calgary
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Zhang R, Pei H, Ru L, Li H, Liu G. Bone morphogenetic protein 7 upregulates the expression of nestin and glial fibrillary acidic protein in rats with cerebral ischemia-reperfusion injury. Biomed Rep 2013; 1:895-900. [PMID: 24649049 DOI: 10.3892/br.2013.164] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2013] [Accepted: 08/23/2013] [Indexed: 11/06/2022] Open
Abstract
Bone morphogenetic protein 7 (BMP7) is a member of the transforming growth factor-β (TGF-β) superfamily and was initially identified as a protein that may induce bone and cartilage growth in the bone matrix. The present study was conducted in order to investigate the effect of BMP7 on the expression of nestin and glial fibrillary acidic protein (GFAP) in the brain tissue of rats after cerebral ischemia-reperfusion injury. A total of 40 adult healthy male Sprague-Dawley rats were used in this study, of which 10 randomly received a sham operation and the remaining 30 were subjected to a 2-h ischemia and 24-h reperfusion by ligation of the left external and internal carotid arteries. Twenty successfully modeled rats were equally randomized into the treatment and control groups. The rats in the treatment group were intervened with 250 μl BMP7 (0.1 mg/kg) via tail vein injection, whereas the rats in the control and sham operation groups were injected with an equal volume of sterile water for injection. Neurological deficits were evaluated by the Bederson's method at 24 h after ischemia-reperfusion and the brain infarct volume was assessed by 2,3,5-triphenyl tetrazolium chloride coloring. The neuronal apoptosis was assessed by terminal deoxynucleotidyl transferase-mediated biotinylated deoxyuridine triphosphate nick end-labelling (TUNEL) staining and the expression of nestin and GFAP in the three groups was analyzed by immunohistochemistry. Bederson's score (t=4.66, P<0.01) and focus infarction (t=6.98, P<0.01) were lower in the BMP7 treatment group compared to those in the control group. In addition, the number of TUNEL-positive cells in the treatment group was lower compared to that in the control group (P<0.01). Compared to the control group, the expression of nestin and GFAP was enhanced in the BMP7 treatment group (P<0.01). Therefore, BMP7 may upregulate the expression of nestin and GFAP and promote neural regeneration to protect animals against ischemia-reperfusion injury.
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Affiliation(s)
- Rui Zhang
- Institute of Cerebrovascular Diseases, The Affiliated Hospital of Qingdao University Medical College, Qingdao, Shandong 266003, P.R. China
| | - Haitao Pei
- Department of Emergency Neurology, The Affiliated Hospital of Qingdao University Medical College, Qingdao, Shandong 266003, P.R. China
| | - Lijuan Ru
- Department of Emergency Neurology, The Affiliated Hospital of Qingdao University Medical College, Qingdao, Shandong 266003, P.R. China
| | - Hongyun Li
- Department of Emergency Neurology, The Affiliated Hospital of Qingdao University Medical College, Qingdao, Shandong 266003, P.R. China
| | - Guangyi Liu
- Institute of Cerebrovascular Diseases, The Affiliated Hospital of Qingdao University Medical College, Qingdao, Shandong 266003, P.R. China
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Hegarty SV, O'Keeffe GW, Sullivan AM. BMP-Smad 1/5/8 signalling in the development of the nervous system. Prog Neurobiol 2013; 109:28-41. [PMID: 23891815 DOI: 10.1016/j.pneurobio.2013.07.002] [Citation(s) in RCA: 126] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2012] [Revised: 07/16/2013] [Accepted: 07/16/2013] [Indexed: 02/07/2023]
Abstract
The transcription factors, Smad1, Smad5 and Smad8, are the pivotal intracellular effectors of the bone morphogenetic protein (BMP) family of proteins. BMPs and their receptors are expressed in the nervous system (NS) throughout its development. This review focuses on the actions of Smad 1/5/8 in the developing NS. The mechanisms by which these Smad proteins regulate the induction of the neuroectoderm, the central nervous system (CNS) primordium, and finally the neural crest, which gives rise to the peripheral nervous system (PNS), are reviewed herein. We describe how, following neural tube closure, the most dorsal aspect of the tube becomes a signalling centre for BMPs, which directs the pattern of the development of the dorsal spinal cord (SC), through the action of Smad1, Smad5 and Smad8. The direct effects of Smad 1/5/8 signalling on the development of neuronal and non-neuronal cells from various neural progenitor cell populations are then described. Finally, this review discusses the neurodevelopmental abnormalities associated with the knockdown of Smad 1/5/8.
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Affiliation(s)
- Shane V Hegarty
- Department of Anatomy & Neuroscience, University College Cork, Cork, Ireland
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Common partner Smad-independent canonical bone morphogenetic protein signaling in the specification process of the anterior rhombic lip during cerebellum development. Mol Cell Biol 2013; 33:1925-37. [PMID: 23459943 DOI: 10.1128/mcb.01143-12] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Bone morphogenetic protein (BMP) signaling is critical for cerebellum development. However, the details of receptor regulated-Smad (R-Smad) and common partner Smad (Co-Smad, or Smad4) involvement are unclear. Here, we report that cerebellum-specific double conditional inactivation of Smad1 and Smad5 (Smad1/5) results in cerebellar hypoplasia, reduced granule cell numbers, and disorganized Purkinje neuron migration during embryonic development. However, single conditional inactivation of either Smad1 or Smad5 did not result in cerebellar abnormalities. Surprisingly, conditional inactivation of Smad4, which is considered to be the central mediator of canonical BMP-Smad signaling, resulted only in very mild cerebellar defects. Conditional inactivation of Smad1/5 led to developmental defects in the anterior rhombic lip (ARL), as shown by reduced cell proliferation and loss of Pax6 and Atoh1 expression. These defects subsequently caused the loss of the nuclear transitory zone and a region of the deep cerebellar nuclei. The normal maturation of the remaining granule cell precursors in the external granular layer (EGL) suggests Smad1/5 signaling is required for the specification process in ARL but not for the subsequent EGL development. Our results demonstrate functional redundancy for Smad1 and Smad5 but functional discrepancy between Smad1/5 and Smad4 during cerebellum development.
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Bond AM, Bhalala OG, Kessler JA. The dynamic role of bone morphogenetic proteins in neural stem cell fate and maturation. Dev Neurobiol 2012; 72:1068-84. [PMID: 22489086 DOI: 10.1002/dneu.22022] [Citation(s) in RCA: 178] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The bone morphogenetic proteins (BMPs) are a group of powerful morphogens that are critical for development of the nervous system. The effects of BMP signaling on neural stem cells are myriad and dynamic, changing with each stage of development. During early development inhibition of BMP signaling differentiates neuroectoderm from ectoderm, and BMP signaling helps to specify neural crest. Thus modulation of BMP signaling underlies formation of both the central and peripheral nervous systems. BMPs secreted from dorsal structures then form a gradient which helps pattern the dorsal-ventral axis of the developing spinal cord and brain. During forebrain development BMPs sequentially induce neurogenesis and then astrogliogenesis and participate in neurite outgrowth from immature neurons. BMP signaling also plays a critical role in maintaining adult neural stem cell niches in the subventricular zone (SVZ) and subgranular zone (SGZ). BMPs are able to exert such diverse effects through closely regulated temporospatial expression and interaction with other signaling pathways.
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Affiliation(s)
- Allison M Bond
- Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
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22
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Devès M, Bourrat F. Transcriptional mechanisms of developmental cell cycle arrest: problems and models. Semin Cell Dev Biol 2012; 23:290-7. [PMID: 22464972 DOI: 10.1016/j.semcdb.2012.03.003] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2011] [Revised: 02/02/2012] [Accepted: 03/01/2012] [Indexed: 12/30/2022]
Abstract
Metazoans begin their life as a single cell. Then, this cell enters a more or less protracted period of active cell proliferation, which can be considered as the default cellular state. A crucial event, the developmental cell cycle exit, occurs thereafter. This phenomenon allows for differentiation to happen and regulates the final size of organs and organisms. Its control is still poorly understood. Herein, we review some transcriptional mechanisms of cell cycle exit in animals, and propose to use cellular conveyor belts as model systems for its study. We finally point to evidence that suggests that the mechanisms of developmental cell cycle arrest may have to be maintained in adult tissues.
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23
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Fernandes M, Antoine M, Hébert JM. SMAD4 is essential for generating subtypes of neurons during cerebellar development. Dev Biol 2012; 365:82-90. [PMID: 22370000 DOI: 10.1016/j.ydbio.2012.02.017] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2011] [Revised: 02/07/2012] [Accepted: 02/10/2012] [Indexed: 11/27/2022]
Abstract
Cerebellum development involves the coordinated production of multiple neuronal cell types. The cerebellar primordium contains two germinative zones, the rhombic lip (RL) and the ventricular zone (VZ), which generate different types of glutamatergic and GABAergic neurons, respectively. What regulates the specification and production of glutamatergic and GABAergic neurons as well as the subtypes for each of these two broad classes remains largely unknown. Here we demonstrate with conditional genetic approaches in mice that SMAD4, a major mediator of BMP and TGFβ signaling, is required early in cerebellar development for maintaining the RL and generating subsets of RL-derived glutamatergic neurons, namely neurons of the deep cerebellar nuclei, unipolar brush cells, and the late cohort of granule cell precursors (GCPs). The early cohort of GCPs, despite being deficient for SMAD4, is still generated. In addition, the numbers of GABAergic neurons are reduced in the mutant and the distribution of Purkinje cells becomes abnormal. These studies demonstrate a temporally and spatially restricted requirement for SMAD4 in generating subtypes of cerebellar neurons.
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Affiliation(s)
- Marie Fernandes
- Department of Neuroscience, Albert Einstein College of Medicine, Bronx, NY 10461, USA
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24
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Wang B, Harrison W, Overbeek PA, Zheng H. Transposon mutagenesis with coat color genotyping identifies an essential role for Skor2 in sonic hedgehog signaling and cerebellum development. Development 2011; 138:4487-97. [PMID: 21937600 PMCID: PMC3177318 DOI: 10.1242/dev.067264] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/10/2011] [Indexed: 01/15/2023]
Abstract
Correct development of the cerebellum requires coordinated sonic hedgehog (Shh) signaling from Purkinje to granule cells. How Shh expression is regulated in Purkinje cells is poorly understood. Using a novel tyrosinase minigene-tagged Sleeping Beauty transposon-mediated mutagenesis, which allows for coat color-based genotyping, we created mice in which the Ski/Sno family transcriptional co-repressor 2 (Skor2) gene is deleted. Loss of Skor2 leads to defective Purkinje cell development, a severe reduction of granule cell proliferation and a malformed cerebellum. Skor2 is specifically expressed in Purkinje cells in the brain, where it is required for proper expression of Shh. Skor2 overexpression suppresses BMP signaling in an HDAC-dependent manner and stimulates Shh promoter activity, suggesting that Skor2 represses BMP signaling to activate Shh expression. Our study identifies an essential function for Skor2 as a novel transcriptional regulator in Purkinje cells that acts upstream of Shh during cerebellum development.
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Affiliation(s)
- Baiping Wang
- Huffington Center on Aging, Baylor College of Medicine, Houston, TX 77030, USA
| | - Wilbur Harrison
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX 77030, USA
| | - Paul A. Overbeek
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX 77030, USA
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Hui Zheng
- Huffington Center on Aging, Baylor College of Medicine, Houston, TX 77030, USA
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX 77030, USA
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
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25
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Wittmann W, McLennan IS. The male bias in the number of Purkinje cells and the size of the murine cerebellum may require Müllerian inhibiting substance/anti-Müllerian hormone. J Neuroendocrinol 2011; 23:831-8. [PMID: 21732997 DOI: 10.1111/j.1365-2826.2011.02187.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
There is a male bias in the size of the cerebellum, with males, on average, having more Purkinje cells than females. The critical periods in cerebellum development occur when the immature testes secrete Müllerian inhibiting substance (MIS; synonym anti-Müllerian hormone) but only trace levels of testosterone. This suggests that the male bias in the cerebellum is generated by a different mechanism to the testosterone-sensitive reproductive nuclei. Consistent with this, in the present study, we report that Purkinje cells and other cerebella neurones express receptors for MIS, and that MIS(-/-) male mice have female-like numbers of Purkinje cells and a female-like size to other parts of their cerebellum. The size of the cell bodies of Purkinje cells was also dimorphic, although only a minority of this was a result of MIS. This suggests that MIS induces the initial male bias in the cerebellum, which is then refined by pubescent testosterone and/or other sex-specific factors.
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Affiliation(s)
- W Wittmann
- Department of Anatomy and Structural Biology, Brain Health Research Centre, University of Otago, Dunedin, New Zealand
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Smad6 promotes neuronal differentiation in the intermediate zone of the dorsal neural tube by inhibition of the Wnt/beta-catenin pathway. Proc Natl Acad Sci U S A 2011; 108:12119-24. [PMID: 21730158 DOI: 10.1073/pnas.1100160108] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Proliferation of the neural/neuronal progenitor cells (NPCs) at the ventricular zone of the dorsal spinal cord requires the stimuli of Wnt and bone morphogenic protein (BMP). However, how these two signaling pathways are regulated to initiate differentiation in the NPCs as they enter the intermediate zone is not known. Here, we show that Smad6, a negative regulator of BMP signaling, is expressed in the intermediate zone of the chick dorsal spinal cord. Knockdown experiments show that Smad6 is required for promoting NPCs to exit the cell cycle and differentiate into neurons. Although we find that Smad6 inhibits BMP signaling, as expected, we also find that Smad6 unexpectedly inhibits the Wnt/β-catenin pathway. The inhibition of the Wnt/β-catenin pathway by Smad6 is independent of its effect on the BMP pathway. Rather, Smad6 through its N-terminal domain and link region enhances the interaction of C-terminal binding protein with the β-catenin/T cell factor (TCF) complex and the TCF-binding element to inhibit β-catenin-mediated transcriptional activation. Our study provides evidence that transition of NPCs from a proliferative state to a differentiating state is controlled by the dual inhibitory role of Smad6 to both BMP and Wnt signaling at the level of transcription.
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Machold R, Klein C, Fishell G. Genes expressed in Atoh1 neuronal lineages arising from the r1/isthmus rhombic lip. Gene Expr Patterns 2011; 11:349-59. [PMID: 21440680 DOI: 10.1016/j.gep.2011.03.007] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2011] [Revised: 03/17/2011] [Accepted: 03/22/2011] [Indexed: 02/05/2023]
Abstract
During embryogenesis, the rhombic lip of the fourth ventricle is the germinal origin of a diverse collection of neuronal populations that ultimately reside in the brainstem and cerebellum. Rhombic lip neurogenesis requires the bHLH transcription factor Atoh1 (Math1), and commences shortly after neural tube closure (E9.5). Within the rhombomere 1-isthmus region, the rhombic lip first produces brainstem and deep cerebellar neurons (E9.5-E12), followed by granule cell precursors after E12. While Atoh1 function is essential for all of these populations to be specified, the downstream genetic programs that confer specific properties to early and late born Atoh1 lineages are not well characterized. We have performed a comparative microarray analysis of gene expression within early and later born cohorts of Atoh1 expressing neural precursors purified from E14.5 embryos using a transgenic labeling strategy. We identify novel transcription factors, cell surface molecules, and cell cycle regulators within each pool of Atoh1 lineages that likely contribute to their distinct developmental trajectories and cell fates. In particular, our analysis reveals new insights into the genetic programs that regulate the specification and proliferation of granule cell precursors, the putative cell of origin for the majority of medulloblastomas.
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Affiliation(s)
- R Machold
- Smilow Neuroscience Program, Department of Otolaryngology, NYU School of Medicine, New York, NY 10016, USA.
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28
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Kalinovsky A, Boukhtouche F, Blazeski R, Bornmann C, Suzuki N, Mason CA, Scheiffele P. Development of axon-target specificity of ponto-cerebellar afferents. PLoS Biol 2011; 9:e1001013. [PMID: 21346800 PMCID: PMC3035609 DOI: 10.1371/journal.pbio.1001013] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2010] [Accepted: 12/14/2010] [Indexed: 01/19/2023] Open
Abstract
The function of neuronal networks relies on selective assembly of synaptic connections during development. We examined how synaptic specificity emerges in the pontocerebellar projection. Analysis of axon-target interactions with correlated light-electron microscopy revealed that developing pontine mossy fibers elaborate extensive cell-cell contacts and synaptic connections with Purkinje cells, an inappropriate target. Subsequently, mossy fiber-Purkinje cell connections are eliminated resulting in granule cell-specific mossy fiber connectivity as observed in mature cerebellar circuits. Formation of mossy fiber-Purkinje cell contacts is negatively regulated by Purkinje cell-derived BMP4. BMP4 limits mossy fiber growth in vitro and Purkinje cell-specific ablation of BMP4 in mice results in exuberant mossy fiber-Purkinje cell interactions. These findings demonstrate that synaptic specificity in the pontocerebellar projection is achieved through a stepwise mechanism that entails transient innervation of Purkinje cells, followed by synapse elimination. Moreover, this work establishes BMP4 as a retrograde signal that regulates the axon-target interactions during development.
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Affiliation(s)
- Anna Kalinovsky
- Department of Physiology & Cellular Biophysics and Department of Neuroscience, Columbia University, New York, New York, United States of America
| | | | - Richard Blazeski
- Department of Pathology & Cell Biology and Department of Neuroscience and Ophthalmology, Columbia University, New York, New York, United States of America
| | | | - Noboru Suzuki
- Mie University Life Science Research Center of Animal Genomics, Functional Genomics Institute, Japan
| | - Carol A. Mason
- Department of Pathology & Cell Biology and Department of Neuroscience and Ophthalmology, Columbia University, New York, New York, United States of America
| | - Peter Scheiffele
- Department of Physiology & Cellular Biophysics and Department of Neuroscience, Columbia University, New York, New York, United States of America
- Biozentrum, University of Basel, Basel, Switzerland
- * E-mail:
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Abstract
In the last 20 years, it has become clear that developmental genes and their regulators, noncoding RNAs including microRNAs and long-noncoding RNAs, within signaling pathways play a critical role in the pathogenesis of cancer. Many of these pathways were first identified in genetic screens in Drosophila and other lower organisms. Mammalian orthologs were subsequently identified and genes within the pathways cloned and found to regulate cell growth. Genes and pathways expressed during embryonic development, including the Notch, Wnt/β-Catenin, TGF-β/BMP, Shh/Patched, and Hippo pathways are mutated, lost, or aberrantly regulated in a wide variety of human cancers, including skin, breast, blood, and brain cancers, including medulloblastoma. These biochemical pathways affect cell fate determination, axis formation, and patterning during development and regulate tissue homeostasis and regeneration in adults. Medulloblastoma, the most common malignant nervous system tumor in childhood, are thought to arise from disruptions in cerebellar development [reviewed by Marino, S. (2005)]. Defining the extracellular cues and intracellular signaling pathways that control cerebellar neurogenesis, especially granule cell progenitor (GCP) proliferation and differentiation has been useful for developing models to unravel the mechanisms underlying medulloblastoma formation and growth. In this chapter, we will review the development of the cerebellar cortex, highlighting signaling pathways of potential relevance to tumorigenesis.
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Affiliation(s)
- Martine F Roussel
- Department of Tumor Cell Biology and Genetics, St. Jude Children's Research Hospital, Memphis, Tennessee, USA
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30
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Bone morphogenetic protein signaling in the developing telencephalon controls formation of the hippocampal dentate gyrus and modifies fear-related behavior. J Neurosci 2010; 30:6291-301. [PMID: 20445055 DOI: 10.1523/jneurosci.0550-10.2010] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The cortical hem is an embryonic signaling center that generates bone morphogenetic proteins (BMPs) and acts as an organizer for the hippocampus. The role of BMP signaling in hippocampal neurogenesis, however, has not been established. We therefore generated mice that were deficient in Bmpr1b constitutively, and deficient in Bmpr1a conditionally in the dorsal telencephalon. In double mutant male and female mice, the dentate gyrus (DG) was dramatically smaller than in control mice, reflecting decreased production of granule neurons at the peak period of DG neurogenesis. Additionally, the pool of cells that generates new DG neurons throughout life was reduced, commensurate with the smaller size of the DG. Effects of diminished BMP signaling on the cortical hem were at least partly responsible for these defects in DG development. Reduction of the DG and its major extrinsic output to CA3 raised the possibility that the DG was functionally compromised. We therefore looked for behavioral deficits in double mutants and found that the mice were less responsive to fear- or anxiety-provoking stimuli, whether the association of the stimulus with fear or anxiety was learned or innate. Given that no anatomical defects appeared in the double mutant telencephalon outside the DG, our observations support a growing literature that implicates the hippocampus in circuitry mediating fear and anxiety. Our results additionally indicate a requirement for BMP signaling in generating the dorsalmost neuronal lineage of the telencephalon, DG granule neurons, and in the development of the stem cell niche that makes neurons in the adult hippocampus.
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Barneda-Zahonero B, Miñano-Molina A, Badiola N, Fadó R, Xifró X, Saura CA, Rodríguez-Alvarez J. Bone morphogenetic protein-6 promotes cerebellar granule neurons survival by activation of the MEK/ERK/CREB pathway. Mol Biol Cell 2010; 20:5051-63. [PMID: 19846661 DOI: 10.1091/mbc.e09-05-0424] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Bone morphogenetic proteins (BMPs) have been implicated in the generation and postnatal differentiation of cerebellar granule cells (CGCs). Here, we examined the eventual role of BMPs on the survival of these neurons. Lack of depolarization causes CGC death by apoptosis in vivo, a phenomenon that is mimicked in vitro by deprivation of high potassium in cultured CGCs. We have found that BMP-6, but not BMP-7, is able to block low potassium-mediated apoptosis in CGCs. The neuroprotective effect of BMP-6 is not accompanied by an increase of Smad translocation to the nucleus, suggesting that the canonical pathway is not involved. By contrast, activation of the MEK/ERK/CREB pathway by BMP-6 is necessary for its neuroprotective effect, which involves inhibition of caspase activity and an increase in Bcl-2 protein levels. Other pathways involved in the regulation of CGC survival, such as the c-Jun terminal kinase and the phosphatidylinositol 3-kinase (PI3K)-Akt/PKB, were not affected by BMP-6. Moreover, failure of BMP-7 to activate the MEK/ERK/CREB pathway could explain its inability to protect CGCs from low potassium-mediated apoptosis. Thus, this study demonstrates that BMP-6 acting through the noncanonical MEK/ERK/CREB pathway plays a crucial role on CGC survival.
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Affiliation(s)
- Bruna Barneda-Zahonero
- Institut de Neurociencies and Departament de Bioquímica i Biología Molecular, Universitat Autònoma de Barcelona, 08193 Cerdanyola del Valles, Barcelona, Spain
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32
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Abstract
Astrogliosis following spinal cord injury (SCI) involves an early hypertrophic response that is beneficial and a subsequent formation of a dense scar. We investigated the role of bone morphogenetic protein (BMP) signaling in gliosis after SCI and find that BMPR1a and BMPR1b signaling exerts opposing effects on hypertrophy. Conditional ablation of BMPR1a from glial fibrillary acidic protein (GFAP)-expressing cells leads to defective astrocytic hypertrophy, increased infiltration by inflammatory cells, and reduced axon density. BMPR1b-null mice conversely develop "hyperactive" reactive astrocytes and consequently have smaller lesion volumes. The effects of ablation of either receptor are reversed in the double knock-out animals. These findings indicate that BMPR1a and BMPR1b exert directly opposing effects on the initial reactive astrocytic hypertrophy. Also, BMPR1b knock-out mice have an attenuated glial scar in the chronic stages following injury, suggesting that it has a greater role in glial scar progression. To elucidate the differing roles of the two receptors in astrocytes, we examined the effects of ablation of either receptor in serum-derived astrocytes in vitro. We find that the two receptors exert opposing effects on the posttranscriptional regulation of astrocytic microRNA-21. Further, overexpression of microRNA-21 in wild-type serum-derived astrocytes causes a dramatic reduction in cell size accompanied by reduction in GFAP levels. Hence, regulation of microRNA-21 by BMP signaling provides a novel mechanism for regulation of astrocytic size. Targeting specific BMPR subunits for therapeutic purposes may thus provide an approach for manipulating gliosis and enhancing functional outcomes after SCI.
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FOXC1 is required for normal cerebellar development and is a major contributor to chromosome 6p25.3 Dandy-Walker malformation. Nat Genet 2009; 41:1037-42. [PMID: 19668217 DOI: 10.1038/ng.422] [Citation(s) in RCA: 192] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2009] [Accepted: 06/29/2009] [Indexed: 12/22/2022]
Abstract
Dandy-Walker malformation (DWM), the most common human cerebellar malformation, has only one characterized associated locus. Here we characterize a second DWM-linked locus on 6p25.3, showing that deletions or duplications encompassing FOXC1 are associated with cerebellar and posterior fossa malformations including cerebellar vermis hypoplasia (CVH), mega-cisterna magna (MCM) and DWM. Foxc1-null mice have embryonic abnormalities of the rhombic lip due to loss of mesenchyme-secreted signaling molecules with subsequent loss of Atoh1 expression in vermis. Foxc1 homozygous hypomorphs have CVH with medial fusion and foliation defects. Human FOXC1 heterozygous mutations are known to affect eye development, causing a spectrum of glaucoma-associated anomalies (Axenfeld-Rieger syndrome, ARS; MIM no. 601631). We report the first brain imaging data from humans with FOXC1 mutations and show that these individuals also have CVH. We conclude that alteration of FOXC1 function alone causes CVH and contributes to MCM and DWM. Our results highlight a previously unrecognized role for mesenchyme-neuroepithelium interactions in the mid-hindbrain during early embryogenesis.
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Kaplan FS, Xu M, Seemann P, Connor JM, Glaser DL, Carroll L, Delai P, Fastnacht-Urban E, Forman SJ, Gillessen-Kaesbach G, Hoover-Fong J, Köster B, Pauli RM, Reardon W, Zaidi SA, Zasloff M, Morhart R, Mundlos S, Groppe J, Shore EM. Classic and atypical fibrodysplasia ossificans progressiva (FOP) phenotypes are caused by mutations in the bone morphogenetic protein (BMP) type I receptor ACVR1. Hum Mutat 2009; 30:379-90. [PMID: 19085907 DOI: 10.1002/humu.20868] [Citation(s) in RCA: 314] [Impact Index Per Article: 20.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Fibrodysplasia ossificans progressiva (FOP) is an autosomal dominant human disorder of bone formation that causes developmental skeletal defects and extensive debilitating bone formation within soft connective tissues (heterotopic ossification) during childhood. All patients with classic clinical features of FOP (great toe malformations and progressive heterotopic ossification) have previously been found to carry the same heterozygous mutation (c.617G>A; p.R206H) in the glycine and serine residue (GS) activation domain of activin A type I receptor/activin-like kinase 2 (ACVR1/ALK2), a bone morphogenetic protein (BMP) type I receptor. Among patients with FOP-like heterotopic ossification and/or toe malformations, we identified patients with clinical features unusual for FOP. These atypical FOP patients form two classes: FOP-plus (classic defining features of FOP plus one or more atypical features) and FOP variants (major variations in one or both of the two classic defining features of FOP). All patients examined have heterozygous ACVR1 missense mutations in conserved amino acids. While the recurrent c.617G>A; p.R206H mutation was found in all cases of classic FOP and most cases of FOP-plus, novel ACVR1 mutations occur in the FOP variants and two cases of FOP-plus. Protein structure homology modeling predicts that each of the amino acid substitutions activates the ACVR1 protein to enhance receptor signaling. We observed genotype-phenotype correlation between some ACVR1 mutations and the age of onset of heterotopic ossification or on embryonic skeletal development.
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Affiliation(s)
- Frederick S Kaplan
- Department of Orthopaedic Surgery, University Pennsylvania School of Medicine, Philadelphia, Pennsylvania 19104-6081, USA
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Shakèd M, Weissmüller K, Svoboda H, Hortschansky P, Nishino N, Wölfl S, Tucker KL. Histone deacetylases control neurogenesis in embryonic brain by inhibition of BMP2/4 signaling. PLoS One 2008; 3:e2668. [PMID: 18628975 PMCID: PMC2441862 DOI: 10.1371/journal.pone.0002668] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2008] [Accepted: 06/11/2008] [Indexed: 12/11/2022] Open
Abstract
Background Histone-modifying enzymes are essential for a wide variety of cellular processes dependent upon changes in gene expression. Histone deacetylases (HDACs) lead to the compaction of chromatin and subsequent silencing of gene transcription, and they have recently been implicated in a diversity of functions and dysfunctions in the postnatal and adult brain including ocular dominance plasticity, memory consolidation, drug addiction, and depression. Here we investigate the role of HDACs in the generation of neurons and astrocytes in the embryonic brain. Principal Findings As a variety of HDACs are expressed in differentiating neural progenitor cells, we have taken a pharmacological approach to inhibit multiple family members. Inhibition of class I and II HDACs in developing mouse embryos with trichostatin A resulted in a dramatic reduction in neurogenesis in the ganglionic eminences and a modest increase in neurogenesis in the cortex. An identical effect was observed upon pharmacological inhibition of HDACs in in vitro-differentiating neural precursors derived from the same brain regions. A reduction in neurogenesis in ganglionic eminence-derived neural precursors was accompanied by an increase in the production of immature astrocytes. We show that HDACs control neurogenesis by inhibition of the bone morphogenetic protein BMP2/4 signaling pathway in radial glial cells. HDACs function at the transcriptional level by inhibiting and promoting, respectively, the expression of Bmp2 and Smad7, an intracellular inhibitor of BMP signaling. Inhibition of the BMP2/4 signaling pathway restored normal levels of neurogenesis and astrogliogenesis to both ganglionic eminence- and cortex-derived cultures in which HDACs were inhibited. Conclusions Our results demonstrate a transcriptionally-based regulation of BMP2/4 signaling by HDACs both in vivo and in vitro that is critical for neurogenesis in the ganglionic eminences and that modulates cortical neurogenesis. The results also suggest that HDACs may regulate the developmental switch from neurogenesis to astrogliogenesis that occurs in late gestation.
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Affiliation(s)
- Maya Shakèd
- Interdisciplinary Center for Neurosciences, University of Heidelberg, Heidelberg, Germany
| | - Kathrin Weissmüller
- Interdisciplinary Center for Neurosciences, University of Heidelberg, Heidelberg, Germany
| | - Hanno Svoboda
- Interdisciplinary Center for Neurosciences, University of Heidelberg, Heidelberg, Germany
| | - Peter Hortschansky
- Leibniz Institute for Natural Product Research and Infection Biology, Hans Knöll Institute, Jena, Germany
| | - Norikazu Nishino
- Graduate School of Life Science and Systems Engineering, Kyushu Institute of Technology, Kitakyushu, Japan
| | - Stefan Wölfl
- Institute of Pharmacy and Molecular Biotechnology, University of Heidelberg, Heidelberg, Germany
| | - Kerry L. Tucker
- Interdisciplinary Center for Neurosciences, University of Heidelberg, Heidelberg, Germany
- * E-mail:
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Grimmer MR, Weiss WA. BMPs oppose Math1 in cerebellar development and in medulloblastoma. Genes Dev 2008; 22:693-9. [PMID: 18347086 DOI: 10.1101/gad.1657808] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Affiliation(s)
- Matthew R Grimmer
- Department of Neurology, University of California at San Francisco, San Francisco, California 94143, USA
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Abstract
Axon growth is critical to the establishment of neuronal connectivity. The E3 ubiquitin ligase Cdh1-anaphase-promoting complex (Cdh1-APC) and its substrate the transcriptional modulator SnoN form a cell-intrinsic pathway that orchestrates axonal morphogenesis in the mammalian brain. How the Cdh1-APC/SnoN pathway is controlled in the nervous system remained unknown. Here, we report that the TGFbeta-regulated signaling protein Smad2 plays a key role in regulating the Cdh1-APC/SnoN pathway in neurons. We find that Smad2 is expressed in primary granule neurons of the developing rat cerebellar cortex. The Smad signaling pathway is basally activated in neurons. Endogenous Smad2 is phosphorylated, localized in the nucleus, and forms a physical complex with endogenous SnoN in granule neurons. Inhibition of Smad signaling by several distinct approaches, including genetic knock-down of Smad2, stimulates axonal growth. Biochemical evidence and genetic epistasis analyses reveal that Smad2 acts upstream of SnoN in a shared pathway with Cdh1-APC in the control of axonal growth. Remarkably, Smad2 knock-down also overrides the ability of adult rat myelin to inhibit axonal growth. Collectively, our findings define a novel function for Smad2 in regulation of the Cdh1-APC/SnoN cell-intrinsic pathway of axonal morphogenesis, and suggest that inhibition of Smad signaling may hold therapeutic potential in stimulating axonal growth after injury in the CNS.
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Flegel T, Matiasek K, Henke D, Grevel V. Cerebellar cortical degeneration with selective granule cell loss in Bavarian mountain dogs. J Small Anim Pract 2007; 48:462-5. [PMID: 17663663 DOI: 10.1111/j.1748-5827.2006.00257.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Three Bavarian mountain dogs aged between 18 and 20 months, not related to each other, were presented with chronic signs of cerebellar dysfunction. On sagittal T2-weighted magnetic resonance imaging brain images, the tentative diagnosis of cerebellar hypoplasia was established based on an enlarged cerebrospinal fluid space around the cerebellum and an increased cerebrospinal fluid signal between the folia. Post-mortem examination was performed in one dog and did show an overall reduction of cerebellar size. On histopathologic examination, a selective loss of cerebellar granule cells with sparing of Purkinje cells was evident. Therefore, the Bavarian mountain dog is a breed where cerebellar cortical degeneration caused by the rather exceptional selective granule cell loss can be seen as cause of chronic, slowly progressive cerebellar dysfunction starting at an age of several months.
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Affiliation(s)
- T Flegel
- Department of Small Animal Medicine, University of Leipzig, An den Tierkliniken 23, 04103 Leipzig, Germany
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39
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Jonakait GM. The effects of maternal inflammation on neuronal development: possible mechanisms. Int J Dev Neurosci 2007; 25:415-25. [DOI: 10.1016/j.ijdevneu.2007.08.017] [Citation(s) in RCA: 89] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2007] [Accepted: 08/27/2007] [Indexed: 10/22/2022] Open
Affiliation(s)
- G. Miller Jonakait
- Department of Biological SciencesNew Jersey Institute of Technology195 University AvenueNewarkNJ07102United States
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40
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Zhao Y, Kwan KM, Mailloux CM, Lee WK, Grinberg A, Wurst W, Behringer RR, Westphal H. LIM-homeodomain proteins Lhx1 and Lhx5, and their cofactor Ldb1, control Purkinje cell differentiation in the developing cerebellum. Proc Natl Acad Sci U S A 2007; 104:13182-6. [PMID: 17664423 PMCID: PMC1941824 DOI: 10.1073/pnas.0705464104] [Citation(s) in RCA: 106] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Purkinje cells are one of the major types of neurons that form the neural circuitry in the cerebellum essential for fine control of movement and posture. During development, Purkinje cells also are critically involved in the regulation of proliferation of progenitors of granule cells, the other major type of neurons in the cerebellum. The process that controls differentiation of Purkinje cells from their early precursors is poorly understood. Here we report that two closely related LIM-homeobox genes, Lhx1 and Lhx5, were expressed in the developing Purkinje cells soon after they exited the cell cycle and migrated out of the cerebellar ventricular zone. Double-mutant mice lacking function of both Lhx1 and Lhx5 showed a severe reduction in the number of Purkinje cells. In addition, targeted inactivation of Ldb1, which encodes a cofactor for all LIM-homeodomain proteins, resulted in a similar phenotype. Our studies thus provide evidence that these transcription regulators are essential for controlling Purkinje cell differentiation in the developing mammalian cerebellum.
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Affiliation(s)
- Yangu Zhao
- *Laboratory of Mammalian Genes and Development, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892-2790
| | - Kin-Ming Kwan
- Department of Molecular Genetics, University of Texas M. D. Anderson Cancer Center, Houston, TX 77030; and
| | - Christina M. Mailloux
- *Laboratory of Mammalian Genes and Development, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892-2790
| | - Woon-Kyu Lee
- *Laboratory of Mammalian Genes and Development, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892-2790
| | - Alexander Grinberg
- *Laboratory of Mammalian Genes and Development, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892-2790
| | - Wolfgang Wurst
- Institute of Developmental Genetics, National Research Center (GSF Research Center), Munich/Neuherberg D-85764, Germany
| | - Richard R. Behringer
- Department of Molecular Genetics, University of Texas M. D. Anderson Cancer Center, Houston, TX 77030; and
| | - Heiner Westphal
- *Laboratory of Mammalian Genes and Development, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892-2790
- To whom correspondence should be addressed. E-mail:
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Abstract
Members of the Zic family of zinc finger transcription factors play critical roles in a variety of developmental processes. They are involved in development of neural tissues and the neural crest, in left-right axis patterning, in somite development, and in formation of the cerebellum. In addition to their roles in cell-fate specification, zic genes also promote cell proliferation. Further, they are expressed in postmitotic cells of the cerebellum and in retinal ganglion cells. Efforts to determine the role of individual zic genes within an array of developmental and cellular processes are complicated by overlapping patterns of zic gene expression and strong sequence conservation within this gene family. Nevertheless, substantial progress has been made. This review summarizes our knowledge of the molecular events that govern the activities of zic family members, including emerging relationships between upstream signaling pathways and zic genes. In addition, advancements in our understanding of the molecular events downstream of Zic transcription factors are reviewed. Despite significant progress, however, much remains to be learned regarding the mechanisms through which zic genes exert their function in a variety of different contexts.
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Affiliation(s)
- Christa S Merzdorf
- Department of Cell Biology and Neuroscience, Montana State University, Bozeman, Montana.
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42
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Abstract
During development of the mammalian nervous system, neural stem cells generate neurons first and glia second, thereby allowing the initial establishment of neural circuitry, and subsequent matching of glial numbers and position to that circuitry. Here, we have reviewed work addressing the mechanisms underlying this timed cell genesis, with a particular focus on the developing cortex. These studies have defined an intriguing interplay between intrinsic epigenetic status, transcription factors, and environmental cues, all of which work together to establish this fascinating and complex biological timing mechanism.
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Affiliation(s)
- Freda D Miller
- Developmental and Stem Cell Biology, Hospital for Sick Children, Toronto M5G 1X8, Canada.
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43
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Cheng LE, Zhang J, Reed RR. The transcription factor Zfp423/OAZ is required for cerebellar development and CNS midline patterning. Dev Biol 2007; 307:43-52. [PMID: 17524391 PMCID: PMC2866529 DOI: 10.1016/j.ydbio.2007.04.005] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2006] [Revised: 04/06/2007] [Accepted: 04/06/2007] [Indexed: 01/20/2023]
Abstract
The dorsal midline structure is critical for patterning the developing central nervous system (CNS). We show here that Zfp423/OAZ, a multiple zinc-finger transcription factor involved in both OE/EBF and BMP-signaling pathways, is required for the proper formation of forebrain and hindbrain midline structures. During embryogenesis, OAZ is highly expressed at the dorsal neuroepithelium flanking the roof plate. OAZ-deficient mice are ataxic, attributed to the reduction of the cerebellar vermis and some regions of the hemispheres. Characterization of postnatal cerebellar development shows defects in Purkinje cell differentiation and granule cell proliferation. In the forebrain, dorsal telencephalic commissural neurons project axons, but these axons fail to cross the midline and midline glial cells are abnormally distributed. Moreover, there are malformations in midline structures including the septum, thalamus and hypothalamus, suggesting a pivotal role of OAZ in CNS midline patterning.
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Affiliation(s)
- Li E Cheng
- Center for Sensory Biology, Department of Molecular Biology and Genetics, Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
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44
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Machold RP, Kittell DJ, Fishell GJ. Antagonism between Notch and bone morphogenetic protein receptor signaling regulates neurogenesis in the cerebellar rhombic lip. Neural Dev 2007; 2:5. [PMID: 17319963 PMCID: PMC1820780 DOI: 10.1186/1749-8104-2-5] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2006] [Accepted: 02/23/2007] [Indexed: 11/17/2022] Open
Abstract
Background During the embryonic development of the cerebellum, neurons are produced from progenitor cells located along a ventricular zone within dorsal rhombomere 1 that extends caudally to the roof plate of the fourth ventricle. The apposition of the caudal neuroepithelium and roof plate results in a unique inductive region termed the cerebellar rhombic lip, which gives rise to granule cell precursors and other glutamatergic neuronal lineages. Recently, we and others have shown that, at early embryonic stages prior to the emergence of granule cell precursors (E12), waves of neurogenesis in the cerebellar rhombic lip produce specific hindbrain nuclei followed by deep cerebellar neurons. How the induction of rhombic lip-derived neurons from cerebellar progenitors is regulated during this phase of cerebellar development to produce these temporally discrete neuronal populations while maintaining a progenitor pool for subsequent neurogenesis is not known. Results Employing both gain- and loss-of-function methods, we find that Notch1 signaling in the cerebellar primordium regulates the responsiveness of progenitor cells to bone morphogenetic proteins (BMPs) secreted from the roof plate that stimulate the production of rhombic lip-derived neurons. In the absence of Notch1, cerebellar progenitors are depleted during the early production of hindbrain neurons, resulting in a severe decrease in the deep cerebellar nuclei that are normally born subsequently. Mechanistically, we demonstrate that Notch1 activity prevents the induction of Math1 by antagonizing the BMP receptor-signaling pathway at the level of Msx2 expression. Conclusion Our results provide a mechanism by which a balance between neural induction and maintenance of neural progenitors is achieved in the rhombic lip throughout embryonic development.
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Affiliation(s)
- Robert P Machold
- New York University School of Medicine Smilow Neuroscience Program Department of Otolaryngology 522 First Avenue New York, NY 10016, USA
| | - Deborah Jones Kittell
- New York University School of Medicine Smilow Neuroscience Program Department of Cell Biology 522 First Avenue New York, NY 10016, USA
| | - Gordon J Fishell
- New York University School of Medicine Smilow Neuroscience Program Department of Cell Biology 522 First Avenue New York, NY 10016, USA
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Chen HL, Panchision DM. Concise Review: Bone Morphogenetic Protein Pleiotropism in Neural Stem Cells and Their Derivatives-Alternative Pathways, Convergent Signals. Stem Cells 2006; 25:63-8. [PMID: 16973830 DOI: 10.1634/stemcells.2006-0339] [Citation(s) in RCA: 76] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Bone morphogenetic proteins (BMPs) are a class of morphogens that are critical regulators of the central nervous system (CNS), peripheral nervous system, and craniofacial development. Modulation of BMP signaling also appears to be an important component of the postnatal stem cell niche. However, describing a comprehensive model of BMP actions is complicated by their paradoxical effects in precursor cells, which include dorsal specification, promoting proliferation or mitotic arrest, cell survival or death, and neuronal or glial fate. In addition, in postmitotic neurons BMPs can promote dendritic growth, act as axonal chemorepellants, and stabilize synapses. Although many of these responses depend on interactions with other incoming signals, some reflect the recruitment of distinct BMP signal transduction pathways. In this review, we classify the diverse effects of BMPs on neural cells, focus on the known mechanisms that specify distinct responses, and discuss the remaining challenges in identifying the cellular basis of BMP pleiotropism. Addressing these issues may have importance for stem cell mobilization, differentiation, and cell integration/survival in reparative therapies.
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Affiliation(s)
- Hui-Ling Chen
- Center for Neuroscience Research, Children's National Medical Center, Washington, DC 20010, USA
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46
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Chizhikov VV, Lindgren AG, Currle DS, Rose MF, Monuki ES, Millen KJ. The roof plate regulates cerebellar cell-type specification and proliferation. Development 2006; 133:2793-804. [PMID: 16790481 DOI: 10.1242/dev.02441] [Citation(s) in RCA: 128] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
During embryogenesis, the isthmic organizer, a well-described signaling center at the junction of the mid-hindbrain, establishes the cerebellar territory along the anterior/posterior axis of the neural tube. Mechanisms specifying distinct populations within the early cerebellar anlage are less defined. Using a newly developed gene expression map of the early cerebellar anlage, we demonstrate that secreted signals from the rhombomere 1 roof plate are both necessary and sufficient for specification of the adjacent cerebellar rhombic lip and its derivative fates. Surprisingly, we show that the roof plate is not absolutely required for initial specification of more distal cerebellar cell fates, but rather regulates progenitor proliferation and cell position within the cerebellar anlage. Thus, in addition to the isthmus, the roof plate represents an important signaling center controlling multiple aspects of cerebellar patterning.
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Affiliation(s)
- Victor V Chizhikov
- Department of Human Genetics, University of Chicago, 920 E. 58th Street, CLSC 319 Chicago, IL 60637, USA
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