scholarly journals The Ciliopathy Gene Ftm/Rpgrip1l Controls Mouse Forebrain Patterning via Region-Specific Modulation of Hedgehog/Gli Signaling

2018 ◽  
Author(s):  
Abraham Andreu-Cervera ◽  
Isabelle Anselme ◽  
Alice Karam ◽  
Martin Catala ◽  
Sylvie Schneider-Maunoury
Keyword(s):  
Sonic Hedgehog ◽  
Primary Cilia ◽  
System Development ◽  
Critical Role ◽  
Ground Level ◽  
Nervous System Development ◽  
Gli Transcription Factors ◽  
Optic Vesicles ◽  
Specific Control

ABSTRACTPrimary cilia are essential for central nervous system development. In the mouse, they play a critical role in patterning the spinal cord and telencephalon via the regulation of Hedgehog/Gli signaling. However, despite the frequent disruption of this signaling pathway in human forebrain malformations, the role of primary cilia in forebrain morphogenesis has been little investigated outside the telencephalon. Here we studied development of the diencephalon, hypothalamus and eyes in mutant mice in which the Ftm/Rgprip1l ciliopathy gene is disrupted. At the end of gestation, Ftm-/- fetuses displayed anophthalmia, a reduction of the ventral hypothalamus and a disorganization of diencephalic nuclei and axonal tracts. In Ftm-/- embryos, we found that the ventral forebrain structures and the rostral thalamus were missing. Optic vesicles formed but lacked the optic cups. We analyzed the molecular causes of these defects. In Ftm-/- embryos, Sonic hedgehog (Shh) expression was lost in the ventral forebrain but maintained in the zona limitans intrathalamica (ZLI), the mid-diencephalic organizer. In the diencephalon, Gli activity was dampened in regions adjacent to the Shh-expressing ZLI but displayed a higher Hh-independent ground level in the other regions. Our data uncover a complex role of cilia in development of the diencephalon, hypothalamus and eyes via the region-specific control of the ratio of activator and repressor forms of the Gli transcription factors. They call for a closer examination of forebrain defects in severe ciliopathies and for a search for ciliopathy genes as modifiers in other human conditions with forebrain defects.

scholarly journals The role of astrocyte‐mediated plasticity in neural circuit development and function

2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Nelson A. Perez-Catalan ◽  
Chris Q. Doe ◽  
Sarah D. Ackerman
Keyword(s):  
Nervous System ◽  
Neural Plasticity ◽  
Neural Circuit ◽  
System Development ◽  
Critical Role ◽  
Nervous System Development ◽  
Functional Changes ◽  
Sensory Evoked ◽  
And Function

AbstractNeuronal networks are capable of undergoing rapid structural and functional changes called plasticity, which are essential for shaping circuit function during nervous system development. These changes range from short-term modifications on the order of milliseconds, to long-term rearrangement of neural architecture that could last for the lifetime of the organism. Neural plasticity is most prominent during development, yet also plays a critical role during memory formation, behavior, and disease. Therefore, it is essential to define and characterize the mechanisms underlying the onset, duration, and form of plasticity. Astrocytes, the most numerous glial cell type in the human nervous system, are integral elements of synapses and are components of a glial network that can coordinate neural activity at a circuit-wide level. Moreover, their arrival to the CNS during late embryogenesis correlates to the onset of sensory-evoked activity, making them an interesting target for circuit plasticity studies. Technological advancements in the last decade have uncovered astrocytes as prominent regulators of circuit assembly and function. Here, we provide a brief historical perspective on our understanding of astrocytes in the nervous system, and review the latest advances on the role of astroglia in regulating circuit plasticity and function during nervous system development and homeostasis.

scholarly journals A critical role of autocrine sonic hedgehog signaling in human CD138+ myeloma cell survival and drug resistance

Blood ◽  
2014 ◽  
Vol 124 (13) ◽  
pp. 2061-2071 ◽  
Author(s):  
Zhiqiang Liu ◽  
Jingda Xu ◽  
Jin He ◽  
Yuhuan Zheng ◽  
Haiyan Li ◽  
...  
Keyword(s):  
Drug Resistance ◽  
Cell Survival ◽  
Sonic Hedgehog ◽  
Hedgehog Signaling ◽  
Critical Role ◽  
Myeloma Cell ◽  
Sonic Hedgehog Signaling ◽  
Key Points

Key Points CD138+ MM cells are a major source of SHH. Autocrine SHH enhances MM drug resistance.

scholarly journals Dosage-Dependent Effects of Akt1/Protein Kinase Bα (PKBα) and Akt3/PKBγ on Thymus, Skin, and Cardiovascular and Nervous System Development in Mice

2005 ◽  
Vol 25 (23) ◽  
pp. 10407-10418 ◽  
Author(s):  
Zhong-Zhou Yang ◽  
Oliver Tschopp ◽  
Nicolas Di-Poï ◽  
Elisabeth Bruder ◽  
Anne Baudry ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Cell Cycle Progression ◽  
System Development ◽  
Critical Role ◽  
Nervous System Development ◽  
Mouse Development ◽  
Double Knockout ◽  
Developmental Defects ◽  
Regulation Of Metabolism ◽  
Survival And Development

ABSTRACT Akt/protein kinase B (PKB) plays a critical role in the regulation of metabolism, transcription, cell migration, cell cycle progression, and cell survival. The existence of viable knockout mice for each of the three isoforms suggests functional redundancy. We generated mice with combined mutant alleles of Akt1 and Akt3 to study their effects on mouse development. Here we show that Akt1 − / − Akt3 +/ − mice display multiple defects in the thymus, heart, and skin and die within several days after birth, while Akt1 +/ − Akt3 − / − mice survive normally. Double knockout (Akt1 − / − Akt3 − / −) causes embryonic lethality at around embryonic days 11 and 12, with more severe developmental defects in the cardiovascular and nervous systems. Increased apoptosis was found in the developing brain of double mutant embryos. These data indicate that the Akt1 gene is more essential than Akt3 for embryonic development and survival but that both are required for embryo development. Our results indicate isoform-specific and dosage-dependent effects of Akt on animal survival and development.

scholarly journals The Role of Sonic Hedgehog in Human Holoprosencephaly and Short-Rib Polydactyly Syndromes

2021 ◽  
Vol 22 (18) ◽  
pp. 9854
Author(s):  
Christine Loo ◽  
Michael Pearen ◽  
Grant Ramm
Keyword(s):  
Human Development ◽  
Sonic Hedgehog ◽  
Mammalian Cells ◽  
Animal Studies ◽  
Primary Cilia ◽  
Genetic Mutation ◽  
Wide Variability ◽  
Using Data ◽  
Differentiation And Proliferation

The Hedgehog (HH) signalling pathway is one of the major pathways controlling cell differentiation and proliferation during human development. This pathway is complex, with HH function influenced by inhibitors, promotors, interactions with other signalling pathways, and non-genetic and cellular factors. Many aspects of this pathway are not yet clarified. The main features of Sonic Hedgehog (SHH) signalling are discussed in relation to its function in human development. The possible role of SHH will be considered using examples of holoprosencephaly and short-rib polydactyly (SRP) syndromes. In these syndromes, there is wide variability in phenotype even with the same genetic mutation, so that other factors must influence the outcome. SHH mutations were the first identified genetic causes of holoprosencephaly, but many other genes and environmental factors can cause malformations in the holoprosencephaly spectrum. Many patients with SRP have genetic defects affecting primary cilia, structures found on most mammalian cells which are thought to be necessary for canonical HH signal transduction. Although SHH signalling is affected in both these genetic conditions, there is little overlap in phenotype. Possible explanations will be canvassed, using data from published human and animal studies. Implications for the understanding of SHH signalling in humans will be discussed.

Spalt modifies EGFR-mediated induction of chordotonal precursors in the embryonic PNS of Drosophila promoting the development of oenocytes

Development ◽  
2001 ◽  
Vol 128 (5) ◽  
pp. 711-722 ◽  
Author(s):  
T.E. Rusten ◽  
R. Cantera ◽  
J. Urban ◽  
G. Technau ◽  
F.C. Kafatos ◽  
...  
Keyword(s):  
Nervous System ◽  
Cell Fate ◽  
System Development ◽  
Cell Types ◽  
Nervous System Development ◽  
Dual Function ◽  
Evolutionarily Conserved ◽  
A Cell ◽  
And Migration

Genes of the spalt family encode nuclear zinc finger proteins. In Drosophila melanogaster, they are necessary for the establishment of head/trunk identity, correct tracheal migration and patterning of the wing imaginal disc. Spalt proteins display a predominant pattern of expression in the nervous system, not only in Drosophila but also in species of fish, mouse, frog and human, suggesting an evolutionarily conserved role for these proteins in nervous system development. Here we show that Spalt works as a cell fate switch between two EGFR-induced cell types, the oenocytes and the precursors of the pentascolopodial organ in the embryonic peripheral nervous system. We show that removal of spalt increases the number of scolopodia, as a result of extra secondary recruitment of precursor cells at the expense of the oenocytes. In addition, the absence of spalt causes defects in the normal migration of the pentascolopodial organ. The dual function of spalt in the development of this organ, recruitment of precursors and migration, is reminiscent of its role in tracheal formation and of the role of a spalt homologue, sem-4, in the Caenorhabditis elegans nervous system.

scholarly journals sli is required for proper morphology and migration of sensory neurons in the Drosophila PNS

2019 ◽  
Vol 14 (1) ◽  
Author(s):  
Madison Gonsior ◽  
Afshan Ismat
Keyword(s):  
Nervous System ◽  
Sensory Neurons ◽  
Glial Cells ◽  
System Development ◽  
Nervous System Development ◽  
Final Position ◽  
Neuron Development ◽  
Guidance Cues ◽  
And Migration

Abstract Neurons and glial cells coordinate with each other in many different aspects of nervous system development. Both types of cells are receiving multiple guidance cues to guide the neurons and glial cells to their proper final position. The lateral chordotonal organs (lch5) of the Drosophila peripheral nervous system (PNS) are composed of five sensory neurons surrounded by four different glial cells, scolopale cells, cap cells, attachment cells and ligament cells. During embryogenesis, the lch5 neurons go through a rotation and ventral migration to reach their final position in the lateral region of the abdomen. We show here that the extracellular ligand sli is required for the proper ventral migration and morphology of the lch5 neurons. We further show that mutations in the Sli receptors Robo and Robo2 also display similar defects as loss of sli, suggesting a role for Slit-Robo signaling in lch5 migration and positioning. Additionally, we demonstrate that the scolopale, cap and attachment cells follow the mis-migrated lch5 neurons in sli mutants, while the ventral stretching of the ligament cells seems to be independent of the lch5 neurons. This study sheds light on the role of Slit-Robo signaling in sensory neuron development.

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