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Molecular Organization and Patterning of the Medulla Oblongata in Health and Disease. Int J Mol Sci 2022; 23:ijms23169260. [PMID: 36012524 PMCID: PMC9409237 DOI: 10.3390/ijms23169260] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2022] [Revised: 08/15/2022] [Accepted: 08/16/2022] [Indexed: 11/17/2022] Open
Abstract
The medulla oblongata, located in the hindbrain between the pons and the spinal cord, is an important relay center for critical sensory, proprioceptive, and motoric information. It is an evolutionarily highly conserved brain region, both structural and functional, and consists of a multitude of nuclei all involved in different aspects of basic but vital functions. Understanding the functional anatomy and developmental program of this structure can help elucidate potential role(s) of the medulla in neurological disorders. Here, we have described the early molecular patterning of the medulla during murine development, from the fundamental units that structure the very early medullary region into 5 rhombomeres (r7–r11) and 13 different longitudinal progenitor domains, to the neuronal clusters derived from these progenitors that ultimately make-up the different medullary nuclei. By doing so, we developed a schematic overview that can be used to predict the cell-fate of a progenitor group, or pinpoint the progenitor domain of origin of medullary nuclei. This schematic overview can further be used to help in the explanation of medulla-related symptoms of neurodevelopmental disorders, e.g., congenital central hypoventilation syndrome, Wold–Hirschhorn syndrome, Rett syndrome, and Pitt–Hopkins syndrome. Based on the genetic defects seen in these syndromes, we can use our model to predict which medullary nuclei might be affected, which can be used to quickly direct the research into these diseases to the likely affected nuclei.
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Sacilotto N, Castillo J, Riffo-Campos ÁL, Flores JM, Hibbitt O, Wade-Martins R, López C, Rodrigo MI, Franco L, López-Rodas G. Growth Arrest Specific 1 (Gas1) Gene Overexpression in Liver Reduces the In Vivo Progression of Murine Hepatocellular Carcinoma and Partially Restores Gene Expression Levels. PLoS One 2015; 10:e0132477. [PMID: 26161998 PMCID: PMC4498802 DOI: 10.1371/journal.pone.0132477] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2015] [Accepted: 06/15/2015] [Indexed: 12/29/2022] Open
Abstract
The prognosis of hepatocellular carcinoma patients is usually poor, the size of tumors being a limiting factor for surgical treatments. Present results suggest that the overexpression of Gas1 (growth arrest specific 1) gene reduces the size, proliferating activity and malignancy of liver tumors. Mice developing diethylnitrosamine-induced hepatocellular carcinoma were subjected to hydrodynamic gene delivery to overexpress Gas1 in liver. This treatment significantly (p < 0.05) reduced the number of large tumors, while the difference in the total number of lesions was not significant. Moreover, the number of carcinoma foci in the liver and the number of lung metastases were reduced. These results are related with the finding that overexpression of Gas1 in Hepa 1-6 cells arrests cell cycle before S phase, with a significant (p < 0.01) and concomitant reduction in the expression of cyclin E2 gene. In addition, a triangular analysis of microarray data shows that Gas1 overexpression restores the transcription levels of 150 genes whose expression was affected in the diethylnitrosamine-induced tumors, thirteen of which are involved in the hedgehog signaling pathway. Since the in vivo Gas1 gene delivery to livers of mice carrying hepatocellular carcinoma reduces the size and proliferating activity of tumors, partially restoring the transcriptional profile of the liver, the present study opens promising insights towards a therapeutic approach for hepatocellular carcinoma.
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Affiliation(s)
- Natalia Sacilotto
- Department of Biochemistry and Molecular Biology, University of Valencia, Burjassot, Valencia, Spain
| | - Josefa Castillo
- Department of Biochemistry and Molecular Biology, University of Valencia, Burjassot, Valencia, Spain
- Institute of Health Research INCLIVA, Valencia, Spain
| | - Ángela L. Riffo-Campos
- Department of Biochemistry and Molecular Biology, University of Valencia, Burjassot, Valencia, Spain
- Institute of Health Research INCLIVA, Valencia, Spain
| | - Juana M. Flores
- Department of Medicine and Animal Surgery, University Complutense, Madrid, Spain
| | - Olivia Hibbitt
- Department of Physiology, Anatomy and Genetics, Oxford University, Oxford, United Kingdom
| | - Richard Wade-Martins
- Department of Physiology, Anatomy and Genetics, Oxford University, Oxford, United Kingdom
| | - Carlos López
- Department of Cell Biology, University of Valencia, Burjassot, Valencia, Spain
| | - M. Isabel Rodrigo
- Department of Biochemistry and Molecular Biology, University of Valencia, Burjassot, Valencia, Spain
- Institute of Health Research INCLIVA, Valencia, Spain
| | - Luis Franco
- Department of Biochemistry and Molecular Biology, University of Valencia, Burjassot, Valencia, Spain
- Institute of Health Research INCLIVA, Valencia, Spain
- * E-mail:
| | - Gerardo López-Rodas
- Department of Biochemistry and Molecular Biology, University of Valencia, Burjassot, Valencia, Spain
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Mizeracka K, Heiman MG. The many glia of a tiny nematode: studying glial diversity using Caenorhabditis elegans. WILEY INTERDISCIPLINARY REVIEWS-DEVELOPMENTAL BIOLOGY 2015; 4:151-60. [PMID: 25611728 DOI: 10.1002/wdev.171] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/08/2014] [Revised: 11/20/2014] [Accepted: 12/02/2014] [Indexed: 11/06/2022]
Abstract
UNLABELLED Glia constitute a major, understudied population of cells in the nervous system. Currently, it is appreciated that these cells exhibit vast morphological, functional, and molecular diversity, but our understanding of glial biology is limited. Some key unanswered questions include how glial diversity is generated during development and what functions distinct glial subtypes serve in the mature nervous system. The nematode Caenorhabditis elegans contains a defined set of glia, which have clear morphological and molecular differences, and thus provides a simplified model for understanding glial diversity. In addition, recent experiments suggest that the molecular mechanisms underlying the generation of glial diversity in C. elegans are conserved with those in mammals. In this review, we summarize the surprising diversity of glial subtypes present in this simple organism, and highlight current thinking about what roles they perform in the nervous system. We emphasize how genetic approaches may be used to identify the mechanistic origins of glial diversity, which is key to understanding how glia function in health and disease. For further resources related to this article, please visit the WIREs website. CONFLICT OF INTEREST The authors have declared no conflicts of interest for this article.
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Affiliation(s)
- Karolina Mizeracka
- Division of Genetics, Boston Children's Hospital, Boston, MA, USA; Department of Genetics, Harvard Medical School, Boston, MA, USA
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Panayiotou E, Panayi E, Lapathitis G, Francius C, Clotman F, Kessaris N, Richardson WD, Malas S. Pax6 is expressed in subsets of V0 and V2 interneurons in the ventral spinal cord in mice. Gene Expr Patterns 2013; 13:328-34. [PMID: 23816521 DOI: 10.1016/j.gep.2013.06.004] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2013] [Revised: 06/18/2013] [Accepted: 06/20/2013] [Indexed: 02/06/2023]
Abstract
The embryonic spinal cord in mice is organized into eleven progenitor domains. Cells in each domain first produce neurons and then switch to specifying glia. Five of these domains known as p3, pMN, p2, p1 and p0 are located in the ventral spinal cord and each expresses a unique code of transcription factors (TFs) that define the molecular profile of progenitor cells. This code is largely responsible for determining the subtype specification of neurons generated from each domain. Pax6 codes for a homedomain-containing TF that plays a central role in defining the molecular boundaries between the two ventral-most domains, p3 and pMN. Using fate mapping and gene expression studies we show that PAX6, in addition to each patterning function, is expressed in a group of late born interneurons that derive from the p2 and p0 domains. The p2-derived neurons represent a subset of late born V2b interneurons and their specification depends on Notch signaling. The V0 neurons represent V0v ventral neurons expressing Pax2. Our data demonstrate that interneuron diversity in the ventral spinal cord is more complex than originally appreciated and point to the existence of additional mechanisms that determine interneuron diversity, particularly in the p2 domain.
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Affiliation(s)
- Elena Panayiotou
- The Cyprus Institute of Neurology and Genetics, P.O. Box 23462, 1683 Nicosia, Cyprus; Department of Biological Sciences, University of Cyprus, P.O. Box 20537, 1678 Nicosia, Cyprus
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Endogenous proliferation after spinal cord injury in animal models. Stem Cells Int 2012; 2012:387513. [PMID: 23316243 PMCID: PMC3539424 DOI: 10.1155/2012/387513] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2012] [Revised: 10/06/2012] [Accepted: 10/29/2012] [Indexed: 12/12/2022] Open
Abstract
Spinal cord injury (SCI) results in motor and sensory deficits, the severity of which depends on the level and extent of the injury. Animal models for SCI research include transection, contusion, and compression mouse models. In this paper we will discuss the endogenous stem cell response to SCI in animal models. All SCI animal models experience a similar peak of cell proliferation three days after injury; however, each specific type of injury promotes a specific and distinct stem cell response. For example, the transection model results in a strong and localized initial increase of proliferation, while in contusion and compression models, the initial level of proliferation is lower but encompasses the entire rostrocaudal extent of the spinal cord. All injury types result in an increased ependymal proliferation, but only in contusion and compression models is there a significant level of proliferation in the lateral regions of the spinal cord. Finally, the fate of newly generated cells varies from a mainly oligodendrocyte fate in contusion and compression to a mostly astrocyte fate in the transection model. Here we will discuss the potential of endogenous stem/progenitor cell manipulation as a therapeutic tool to treat SCI.
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Karus M, Denecke B, ffrench-Constant C, Wiese S, Faissner A. The extracellular matrix molecule tenascin C modulates expression levels and territories of key patterning genes during spinal cord astrocyte specification. Development 2011; 138:5321-31. [DOI: 10.1242/dev.067413] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
The generation of astrocytes during the development of the mammalian spinal cord is poorly understood. Here, we demonstrate for the first time that the extracellular matrix glycoprotein tenascin C regulates the expression of key patterning genes during late embryonic spinal cord development, leading to a timely maturation of gliogenic neural precursor cells. We first show that tenascin C is expressed by gliogenic neural precursor cells during late embryonic development. The loss of tenascin C leads to a sustained generation and delayed migration of Fgfr3-expressing immature astrocytes in vivo. Consistent with an increased generation of astroglial cells, we documented an increased number of GFAP-positive astrocytes at later stages. Mechanistically, we could demonstrate an upregulation and domain shift of the patterning genes Nkx6.1 and Nkx2.2 in vivo. In addition, sulfatase 1, a known downstream target of Nkx2.2 in the ventral spinal cord, was also upregulated. Sulfatase 1 regulates growth factor signalling by cleaving sulphate residues from heparan sulphate proteoglycans. Consistent with this function, we observed changes in both FGF2 and EGF responsiveness of spinal cord neural precursor cells. Taken together, our data implicate Tnc in the regulation of proliferation and lineage progression of astroglial progenitors in specific domains of the developing spinal cord.
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Affiliation(s)
- Michael Karus
- Department for Cell Morphology and Molecular Neurobiology, Ruhr-University Bochum, Universitätsstraße 150, 44780 Bochum, Germany
- International Graduate School of Neuroscience, Ruhr-University Bochum, Universitätsstraße 150, 44780 Bochum, Germany
| | | | - Charles ffrench-Constant
- Medical Research Council Centre for Regenerative Medicine and Multiple Sclerosis Society Translational Research Centre, Centre for Inflammation Research, The Queen’s Medical Research Institute, University of Edinburgh, Edinburgh EH16 4TJ, UK
| | - Stefan Wiese
- International Graduate School of Neuroscience, Ruhr-University Bochum, Universitätsstraße 150, 44780 Bochum, Germany
- Group for Molecular Cell Biology, Ruhr-University Bochum, Universitätsstraße 150, 44780 Bochum, Germany
| | - Andreas Faissner
- Department for Cell Morphology and Molecular Neurobiology, Ruhr-University Bochum, Universitätsstraße 150, 44780 Bochum, Germany
- International Graduate School of Neuroscience, Ruhr-University Bochum, Universitätsstraße 150, 44780 Bochum, Germany
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Abstract
Oligodendrocytes and astrocytes are macroglial cells of the vertebrate central nervous system. These cells have diverse roles in the maintenance of neurological function. In the embryo, the genetic mechanisms that underlie the specification of macroglial precursors in vivo appear strikingly similar to those that regulate the development of the diverse neuron types. The switch from producing neuronal to glial subtype-specific precursors can be modelled as an interplay between region-restricted components and temporal regulators that determine neurogenic or gliogenic phases of development, contributing to glial diversity. Gaining insight into the developmental genetics of macroglia has great potential to improve our understanding of a variety of neurological disorders in humans.
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Lek M, Dias JM, Marklund U, Uhde CW, Kurdija S, Lei Q, Sussel L, Rubenstein JL, Matise MP, Arnold HH, Jessell TM, Ericson J. A homeodomain feedback circuit underlies step-function interpretation of a Shh morphogen gradient during ventral neural patterning. Development 2010; 137:4051-60. [PMID: 21062862 DOI: 10.1242/dev.054288] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
The deployment of morphogen gradients is a core strategy to establish cell diversity in developing tissues, but little is known about how small differences in the concentration of extracellular signals are translated into robust patterning output in responding cells. We have examined the activity of homeodomain proteins, which are presumed to operate downstream of graded Shh signaling in neural patterning, and describe a feedback circuit between the Shh pathway and homeodomain transcription factors that establishes non-graded regulation of Shh signaling activity. Nkx2 proteins intrinsically strengthen Shh responses in a feed-forward amplification and are required for ventral floor plate and p3 progenitor fates. Conversely, Pax6 has an opposing function to antagonize Shh signaling, which provides intrinsic resistance to Shh responses and is important to constrain the inductive capacity of the Shh gradient over time. Our data further suggest that patterning of floor plate cells and p3 progenitors is gated by a temporal switch in neuronal potential, rather than by different Shh concentrations. These data establish that dynamic, non-graded changes in responding cells are essential for Shh morphogen interpretation, and provide a rationale to explain mechanistically the phenomenon of cellular memory of morphogen exposure.
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Affiliation(s)
- Madelen Lek
- Department of Cell and Molecular Biology, Karolinska Institutet, Stockholm, Sweden
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SOX1 links the function of neural patterning and Notch signalling in the ventral spinal cord during the neuron-glial fate switch. Biochem Biophys Res Commun 2009; 390:1114-20. [DOI: 10.1016/j.bbrc.2009.08.154] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2009] [Accepted: 08/27/2009] [Indexed: 12/13/2022]
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Lin Y, Cai Z, Huang S, Yang L, Wang C, Liu Z, Cao J, An Y, Zhang H. Ptc, Smo, Sufu, and the Hedgehog signaling pathway in amphioxus. Evol Dev 2009; 11:710-8. [DOI: 10.1111/j.1525-142x.2009.00378.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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