New Insights Into the Roles of Retinoic Acid Signaling in Nervous System Development and the Establishment of Neurotransmitter Systems

Retinoic acid (RA) plays major roles during nervous system development, and during regeneration of the adult nervous system. We have previously shown that components of the RA signaling pathway are upregulated after optic nerve injury, and that exogenous application of all-trans retinoic acid (ATRA) greatly increases the survival of axotomized retinal ganglion cells (RGCs). The objective of the present study is to investigate the effects of ATRA application on the macrophages in the optic nerve after injury, and to determine whether this affects axonal regeneration. The optic nerve was crushed and treated with PBS, ATRA and/or clodronate-loaded liposomes. Nerves were examined at one and two weeks after axotomy with light microscopy, immunocytochemistry and electron microscopy. ATRA application to the optic nerve caused transient increases in the number of macrophages and microglia one week after injury. The macrophages are consistently labeled with M2-type markers, and have considerable phagocytic activity. ATRA increased ultrastructural features of ongoing phagocytic activity in macrophages at one and two weeks. ATRA treatment also significantly increased the numbers of regenerating GAP-43-labeled axons. Clodronate liposome treatment depleted macrophage numbers by 80%, completely eliminated the ATRA-mediated increase in axonal regeneration, and clodronate treatment alone decreased axonal numbers by 30%. These results suggest that the success of axon regeneration is partially dependent on the presence of debris-phagocytosing macrophages, and that the increases in regeneration caused by ATRA are in part due to their increased numbers. Further studies will examine whether macrophage depletion affects RGC survival.

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Regulation of miRNAs during Retinoic Acid-Induced Regeneration of a Molluscan Central Nervous System

10.20944/preprints201808.0368.v1 ◽

2018 ◽

Author(s):

Sarah E. Walker ◽

Gaynor E. Spencer ◽

Alexsandr Necakov ◽

Robert L. Carlone

Keyword(s):

Nervous System ◽

Retinoic Acid ◽

Lymnaea Stagnalis ◽

System Development ◽

Growth Cones ◽

Nervous System Development ◽

Biologically Active ◽

Neuronal Outgrowth ◽

First Time

Retinoic acid (RA) is the biologically active metabolite of vitamin A,and has become a well-established factor that induces neurite outgrowth and regeneration in both vertebrates and invertebrates. However, the underlying regulatory mechanisms that may mediate RA-induced neurite sprouting remain unclear. In the past decade, microRNAs have emerged as important regulators of nervous system development and regeneration, and have been shown to contribute to processes such as neurite sprouting. However, few studies have demonstrated the role of miRNAs in RA-induced neurite sprouting. By R-Seq analysis, we identify 482 miRNAs in the regenerating CNS of the mollusc Lymnaea stagnalis, 219 of which represent potentially novel miRNAs. Of the remaining conserved miRNAs, 38 show a statistically significant up or downregulation in regenerating CNS as a result of RA treatment. We further characterized the expression of one neuronally-enriched miRNA upregulated by RA, miR-124. We demonstrate for the first time that miR-124 is expressed within the cell bodies and neurites of regenerating motorneurons. Moreover, we identify miR-124 expression within the growth cones of cultured ciliary motorneurons (Pedal A), whereas expression from the growth cones of another class of respiratory motorneurons (RPA) was absent in vitro. These findings support our hypothesis miRNAs are important regulators of retinoic acid induced neuronal outgrowth and regeneration in regeneration-competent species.

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Identification and Characterization of microRNAs during Retinoic Acid-Induced Regeneration of a Molluscan Central Nervous System

International Journal of Molecular Sciences ◽

10.3390/ijms19092741 ◽

2018 ◽

Vol 19 (9) ◽

pp. 2741 ◽

Cited By ~ 8

Author(s):

Sarah Walker ◽

Gaynor Spencer ◽

Aleksandar Necakov ◽

Robert Carlone

Keyword(s):

Central Nervous System ◽

Nervous System ◽

Retinoic Acid ◽

Lymnaea Stagnalis ◽

System Development ◽

Growth Cones ◽

Nervous System Development ◽

Biologically Active ◽

Sequencing Analysis

Retinoic acid (RA) is the biologically active metabolite of vitamin A and has become a well-established factor that induces neurite outgrowth and regeneration in both vertebrates and invertebrates. However, the underlying regulatory mechanisms that may mediate RA-induced neurite sprouting remain unclear. In the past decade, microRNAs have emerged as important regulators of nervous system development and regeneration, and have been shown to contribute to processes such as neurite sprouting. However, few studies have demonstrated the role of miRNAs in RA-induced neurite sprouting. By miRNA sequencing analysis, we identify 482 miRNAs in the regenerating central nervous system (CNS) of the mollusc Lymnaea stagnalis, 219 of which represent potentially novel miRNAs. Of the remaining conserved miRNAs, 38 show a statistically significant up- or downregulation in regenerating CNS as a result of RA treatment. We further characterized the expression of one neuronally-enriched miRNA upregulated by RA, miR-124. We demonstrate, for the first time, that miR-124 is expressed within the cell bodies and neurites of regenerating motorneurons. Moreover, we identify miR-124 expression within the growth cones of cultured ciliary motorneurons (pedal A), whereas expression in the growth cones of another class of respiratory motorneurons (right parietal A) was absent in vitro. These findings support our hypothesis that miRNAs are important regulators of retinoic acid-induced neuronal outgrowth and regeneration in regeneration-competent species.

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Retinoic acid treatment recruits macrophages and increases axonal regeneration after optic nerve injury in the frog Rana pipiens

PLoS ONE ◽

10.1371/journal.pone.0255196 ◽

2021 ◽

Vol 16 (11) ◽

pp. e0255196

Author(s):

Valeria De La Rosa-Reyes ◽

Mildred V. Duprey-Díaz ◽

Jonathan M. Blagburn ◽

Rosa E. Blanco

Keyword(s):

Nervous System ◽

Retinoic Acid ◽

Optic Nerve ◽

Nerve Injury ◽

Phagocytic Activity ◽

Axonal Regeneration ◽

Ganglion Cells ◽

System Development ◽

Nervous System Development ◽

Optic Nerve Injury

Retinoic acid (RA) plays major roles during nervous system development, and during regeneration of the adult nervous system. We have previously shown that components of the RA signaling pathway are upregulated after optic nerve injury, and that exogenous application of all-trans retinoic acid (ATRA) greatly increases the survival of axotomized retinal ganglion cells (RGCs). The objective of the present study is to investigate the effects of ATRA application on the macrophages in the optic nerve after injury, and to determine whether this affects axonal regeneration. The optic nerve was crushed and treated with PBS, ATRA and/or clodronate-loaded liposomes. Nerves were examined at one and two weeks after axotomy with light microscopy, immunocytochemistry and electron microscopy. ATRA application to the optic nerve caused transient increases in the number of macrophages and microglia one week after injury. The macrophages are consistently labeled with M2-type markers, and have considerable phagocytic activity. ATRA increased ultrastructural features of ongoing phagocytic activity in macrophages at one and two weeks. ATRA treatment also significantly increased the numbers of regenerating GAP-43-labeled axons. Clodronate liposome treatment depleted macrophage numbers by 80%, completely eliminated the ATRA-mediated increase in axonal regeneration, and clodronate treatment alone decreased axonal numbers by 30%. These results suggest that the success of axon regeneration is partially dependent on the presence of debris-phagocytosing macrophages, and that the increases in regeneration caused by ATRA are in part due to their increased numbers. Further studies will examine whether macrophage depletion affects RGC survival.

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Identification and Characterization of microRNAs during Retinoic Acid-Induced Regeneration of a Molluscan Central Nervous System

10.20944/preprints201809.0123.v1 ◽

2018 ◽

Author(s):

Sarah E. Walker ◽

Gaynor E. Spencer ◽

Aleksandar Necakov ◽

Robert L. Carlone

Keyword(s):

Nervous System ◽

Retinoic Acid ◽

Lymnaea Stagnalis ◽

System Development ◽

Growth Cones ◽

Nervous System Development ◽

Biologically Active ◽

Sequencing Analysis ◽

Mirna Sequencing

Retinoic acid (RA) is the biologically active metabolite of vitamin A and has become a well-established factor that induces neurite outgrowth and regeneration in both vertebrates and invertebrates. However, the underlying regulatory mechanisms that may mediate RA-induced neurite sprouting remain unclear. In the past decade, microRNAs have emerged as important regulators of nervous system development and regeneration, and have been shown to contribute to processes such as neurite sprouting. However, few studies have demonstrated the role of miRNAs in RA-induced neurite sprouting. By miRNA-Sequencing analysis, we identify 482 miRNAs in the regenerating CNS of the mollusc Lymnaea stagnalis, 219 of which represent potentially novel miRNAs. Of the remaining conserved miRNAs, 38 show a statistically significant up or downregulation in regenerating CNS as a result of RA treatment. We further characterized the expression of one neuronally-enriched miRNA upregulated by RA, miR-124. We demonstrate for the first time that miR-124 is expressed within the cell bodies and neurites of regenerating motorneurons. Moreover, we identify miR-124 expression within the growth cones of cultured ciliary motorneurons (Pedal A), whereas expression in the growth cones of another class of respiratory motorneurons (RPA) was absent in vitro. These findings support our hypothesis that miRNAs are important regulators of retinoic acid-induced neuronal outgrowth and regeneration in regeneration-competent species.

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Faculty Opinions recommendation of Genome-wide activity-dependent MeCP2 phosphorylation regulates nervous system development and function.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.13371088.14741249 ◽

2011 ◽

Author(s):

David Sweatt ◽

Faraz Sultan

Keyword(s):

Nervous System ◽

System Development ◽

Nervous System Development ◽

Genome Wide ◽

And Function ◽

Activity Dependent

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Antenatal Glucocorticoids Supplementation and Central Nervous System Development

Current Drug Metabolism ◽

10.2174/1389200211314020002 ◽

2013 ◽

Vol 14 (2) ◽

pp. 160-166

Author(s):

Diego Gazzolo ◽

Laura D. Serpero ◽

Alessandro Frigiola ◽

Raul Abella ◽

Alessandro Giamberti ◽

...

Keyword(s):

Central Nervous System ◽

Nervous System ◽

System Development ◽

Nervous System Development ◽

Central Nervous System Development

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Incorporation of 5-Bromo-2′-deoxyuridine into DNA and Proliferative Behavior of Cerebellar Neuroblasts: All That Glitters Is Not Gold

Cells ◽

10.3390/cells10061453 ◽

2021 ◽

Vol 10 (6) ◽

pp. 1453

Author(s):

Joaquín Martí-Clúa

Keyword(s):

Central Nervous System ◽

Nervous System ◽

System Development ◽

Nervous System Development ◽

Current Data ◽

Cellular Mechanisms ◽

Dividing Cells ◽

The Central Nervous System ◽

Repeated Doses ◽

Pyrimidine Analog

The synthetic halogenated pyrimidine analog, 5-bromo-2′-deoxyuridine (BrdU), is a marker of DNA synthesis. This exogenous nucleoside has generated important insights into the cellular mechanisms of the central nervous system development in a variety of animals including insects, birds, and mammals. Despite this, the detrimental effects of the incorporation of BrdU into DNA on proliferation and viability of different types of cells has been frequently neglected. This review will summarize and present the effects of a pulse of BrdU, at doses ranging from 25 to 300 µg/g, or repeated injections. The latter, following the method of the progressively delayed labeling comprehensive procedure. The prenatal and perinatal development of the cerebellum are studied. These current data have implications for the interpretation of the results obtained by this marker as an index of the generation, migration, and settled pattern of neurons in the developing central nervous system. Caution should be exercised when interpreting the results obtained using BrdU. This is particularly important when high or repeated doses of this agent are injected. I hope that this review sheds light on the effects of this toxic maker. It may be used as a reference for toxicologists and neurobiologists given the broad use of 5-bromo-2′-deoxyuridine to label dividing cells.

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