scholarly journals Role of Fgf signalling in positioning neurogenic regions in the early embryonic vertebrate brain

2017 ◽  
Vol 145 ◽  
pp. S124
Author(s):  
Charlotte Smith ◽  
Emily Trebert ◽  
Marina Pradoz Uhle ◽  
Frank R. Schubert
Keyword(s):  
Vertebrate Brain ◽  
Fgf Signalling

scholarly journals Role of FGF signalling in neural crest cell migration during early chick embryo development

Zygote ◽  
2018 ◽  
Vol 26 (6) ◽  
pp. 457-464 ◽  
Author(s):  
Xiao-tan Zhang ◽  
Guang Wang ◽  
Yan Li ◽  
Manli Chuai ◽  
Kenneth Ka Ho Lee ◽  
...  
Keyword(s):  
Neural Crest ◽  
Neural Tube ◽  
Neural Crest Cell ◽  
Dominant Negative ◽  
Neural Tubes ◽  
Dorsal Neural Tube ◽  
Neural Crest Cell Migration ◽  
Fgf Signalling ◽  
Crest Cell

SummaryFibroblast growth factor (FGF) signalling acts as one of modulators that control neural crest cell (NCC) migration, but how this is achieved is still unclear. In this study, we investigated the effects of FGF signalling on NCC migration by blocking this process. Constructs that were capable of inducing Sprouty2 (Spry2) or dominant-negative FGFR1 (Dn-FGFR1) expression were transfected into the cells making up the neural tubes. Our results revealed that blocking FGF signalling at stage HH10 (neurulation stage) could enhance NCC migration at both the cranial and trunk levels in the developing embryos. It was established that FGF-mediated NCC migration was not due to altering the expression of N-cadherin in the neural tube. Instead, we determined that cyclin D1 was overexpressed in the cranial and trunk levels when Sprouty2 was upregulated in the dorsal neural tube. These results imply that the cell cycle was a target of FGF signalling through which it regulates NCC migration at the neurulation stage.

FGF signalling in the early specification of mesoderm in Xenopus

Development ◽  
1993 ◽  
Vol 118 (2) ◽  
pp. 477-487 ◽  
Author(s):  
E. Amaya ◽  
P.A. Stein ◽  
T.J. Musci ◽  
M.W. Kirschner
Keyword(s):  
Dorsal Side ◽  
Dominant Negative ◽  
Early Gene ◽  
Immediate Early ◽  
Mesoderm Induction ◽  
Fgf Receptor ◽  
Muscle Formation ◽  
Fgf Signalling ◽  
Lateral Mesoderm

We have examined the role of FGF signalling in the development of muscle and notochord and in the expression of early mesodermal markers in Xenopus embryos. Disruption of the FGF signalling pathway by expression of a dominant negative construct of the FGF receptor (XFD) generally results in gastrulation defects that are later evident in the formation of the trunk and tail, though head structures are formed nearly normally. These defects are reflected in the loss of notochord and muscle. Even in embryos that show mild defects and gastrulate properly, muscle formation is impaired, suggesting that morphogenesis and tissue differentiation each depend on FGF. The XFD protein inhibits the expression of the immediate early gene brachyury throughout the marginal zone, including the dorsal side; it does not, however, inhibit the dorsal lip marker goosecoid, which is expressed in the first involuting mesoderm at the dorsal side that will underlie the head. The XFD protein also inhibits Xpo expression, an immediate early marker of ventral and lateral mesoderm. These results suggest that FGF is involved in the earliest events of most mesoderm induction that occur before gastrulation and that the early dorsal mesoderm is already composed of two cell populations that differ in their requirements for FGF.

scholarly journals Tumour initiating cells and IGF/FGF signalling contribute to sorafenib resistance in hepatocellular carcinoma

Gut ◽  
2015 ◽  
Vol 66 (3) ◽  
pp. 530-540 ◽  
Author(s):  
Victoria Tovar ◽  
Helena Cornella ◽  
Agrin Moeini ◽  
Samuel Vidal ◽  
Yujin Hoshida ◽  
...  
Keyword(s):  
Hepatocellular Carcinoma ◽  
Growth Factor ◽  
Molecular Mechanisms ◽  
Acquired Resistance ◽  
Gene Signature ◽  
Signalling Pathways ◽  
Fgf Signalling

ObjectiveSorafenib is effective in hepatocellular carcinoma (HCC), but patients ultimately present disease progression. Molecular mechanisms underlying acquired resistance are still unknown. Herein, we characterise the role of tumour-initiating cells (T-ICs) and signalling pathways involved in sorafenib resistance.DesignHCC xenograft mice treated with sorafenib (n=22) were explored for responsiveness (n=5) and acquired resistance (n=17). Mechanism of acquired resistance were assessed by: (1) role of T-ICs by in vitro sphere formation and in vivo tumourigenesis assays using NOD/SCID mice, (2) activation of alternative signalling pathways and (3) efficacy of anti-FGF and anti-IGF drugs in experimental models. Gene expression (microarray, quantitative real-time PCR (qRT-PCR)) and protein analyses (immunohistochemistry, western blot) were conducted. A novel gene signature of sorafenib resistance was generated and tested in two independent cohorts.ResultsSorafenib-acquired resistant tumours showed significant enrichment of T-ICs (164 cells needed to create a tumour) versus sorafenib-sensitive tumours (13 400 cells) and non-treated tumours (1292 cells), p<0.001. Tumours with sorafenib-acquired resistance were enriched with insulin-like growth factor (IGF) and fibroblast growth factor (FGF) signalling cascades (false discovery rate (FDR)<0.05). In vitro, cells derived from sorafenib-acquired resistant tumours and two sorafenib-resistant HCC cell lines were responsive to IGF or FGF inhibition. In vivo, FGF blockade delayed tumour growth and improved survival in sorafenib-resistant tumours. A sorafenib-resistance 175 gene signature was characterised by enrichment of progenitor cell features, aggressive tumorous traits and predicted poor survival in two cohorts (n=442 patients with HCC).ConclusionsAcquired resistance to sorafenib is driven by T-ICs with enrichment of progenitor markers and activation of IGF and FGF signalling. Inhibition of these pathways would benefit a subset of patients after sorafenib progression.

Role of Slit proteins in the vertebrate brain

2002 ◽  
Vol 96 (1-2) ◽  
pp. 91-98 ◽  
Author(s):  
Kim T Nguyen-Ba-Charvet ◽  
Alain Chédotal
Keyword(s):  
Vertebrate Brain

scholarly journals Role of miRNA-9 in Brain Development

2016 ◽  
Vol 10 ◽  
pp. JEN.S32843 ◽  
Author(s):  
Balachandar Radhakrishnan ◽  
A. Alwin Prem Anand
Keyword(s):  
Spinal Cord ◽  
Brain Development ◽  
Spatiotemporal Pattern ◽  
Marker Genes ◽  
Neuron Development ◽  
Neuronal Progenitor ◽  
Vertebrate Brain ◽  
Small Regulatory Rnas ◽  
Her Genes

MicroRNAs (miRNAs) are a class of small regulatory RNAs involved in gene regulation. The regulation is effected by either translational inhibition or transcriptional silencing. In vertebrates, the importance of miRNA in development was discovered from mice and zebrafish dicer knockouts. The miRNA-9 (miR-9) is one of the most highly expressed miRNAs in the early and adult vertebrate brain. It has diverse functions within the developing vertebrate brain. In this article, the role of miR-9 in the developing forebrain (telencephalon and diencephalon), midbrain, hindbrain, and spinal cord of vertebrate species is highlighted. In the forebrain, miR-9 is necessary for the proper development of dorsoventral telencephalon by targeting marker genes expressed in the telencephalon. It regulates proliferation in telencephalon by regulating Foxg1, Pax6, Gsh2, and Meis2 genes. The feedback loop regulation between miR-9 and Nr2e1/Tlx helps in neuronal migration and differentiation. Targeting Foxp1 and Foxp2, and Map1b by miR-9 regulates the radial migration of neurons and axonal development. In the organizers, miR-9 is inversely regulated by hairy1 and Fgf8 to maintain zona limitans interthalamica and midbrain-hindbrain boundary (MHB). It maintains the MHB by inhibiting Fgf signaling genes and is involved in the neurogenesis of the midbrain-hindbrain by regulating Her genes. In the hindbrain, miR-9 modulates progenitor proliferation and differentiation by regulating Her genes and Elav3. In the spinal cord, miR-9 modulates the regulation of Foxp1 and Onecut1 for motor neuron development. In the forebrain, midbrain, and hindbrain, miR-9 is necessary for proper neuronal progenitor maintenance, neurogenesis, and differentiation. In vertebrate brain development, miR-9 is involved in regulating several region-specific genes in a spatiotemporal pattern.

scholarly journals Neuron to glia signaling triggers myelin membrane exocytosis from endosomal storage sites

2006 ◽  
Vol 172 (6) ◽  
pp. 937-948 ◽  
Author(s):  
Katarina Trajkovic ◽  
Ajit Singh Dhaunchak ◽  
José T. Goncalves ◽  
Dirk Wenzel ◽  
Anja Schneider ◽  
...  
Keyword(s):  
Membrane Trafficking ◽  
Proteolipid Protein ◽  
Myelin Membrane ◽  
Vertebrate Brain ◽  
Late Endosomes ◽  
Membrane Growth ◽  
Neuronal Signal ◽  
Endocytosis Pathway ◽  
Guanosine Triphosphatase

During vertebrate brain development, axons are enwrapped by myelin, an insulating membrane produced by oligodendrocytes. Neuron-derived signaling molecules are temporally and spatially required to coordinate oligodendrocyte differentiation. In this study, we show that neurons regulate myelin membrane trafficking in oligodendrocytes. In the absence of neurons, the major myelin membrane protein, the proteolipid protein (PLP), is internalized and stored in late endosomes/lysosomes (LEs/Ls) by a cholesterol-dependent and clathrin-independent endocytosis pathway that requires actin and the RhoA guanosine triphosphatase. Upon maturation, the rate of endocytosis is reduced, and a cAMP-dependent neuronal signal triggers the transport of PLP from LEs/Ls to the plasma membrane. These findings reveal a fundamental and novel role of LEs/Ls in oligodendrocytes: to store and release PLP in a regulated fashion. The release of myelin membrane from LEs/Ls by neuronal signals may represent a mechanism to control myelin membrane growth.

scholarly journals MeCP2 Is Required for Normal Development of GABAergic Circuits in the Thalamus

2010 ◽  
Vol 103 (5) ◽  
pp. 2470-2481 ◽  
Author(s):  
Zhong-Wei Zhang ◽  
Joseph D. Zak ◽  
Hong Liu
Keyword(s):  
Neurodevelopmental Disorder ◽  
Brain Slices ◽  
Inhibitory Neurons ◽  
Gene Encoding ◽  
Vertebrate Brain ◽  
Gabaergic Synapses ◽  
And Function ◽  
Kinetics Of ◽  
Whole Cell Recordings

Methyl-CpG binding protein 2 (MeCP2) is highly expressed in neurons in the vertebrate brain, and mutations of the gene encoding MeCP2 cause the neurodevelopmental disorder Rett syndrome. This study examines the role of MeCP2 in the development and function of thalamic GABAergic circuits. Whole cell recordings were carried out in excitatory neurons of the ventrobasal complex (VB) of the thalamus and in inhibitory neurons of the reticular thalamic nucleus (RTN) in acute brain slices from mice aged P6 through P23. At P14–P16, the number of quantal GABAergic events was decreased in VB neurons but increased in RTN neurons of Mecp2-null mice, without any change in the amplitude or kinetics of quantal events. There was no difference between mutant and wild-type mice in paired-pulse ratios of evoked GABAergic responses in the VB or the RTN. On the other hand, unitary responses evoked by minimal stimulation were decreased in the VB but increased in the RTN of mutants. Similar changes in the frequency of quantal events were observed at P21–P23 in both the VB and RTN. At P6, however, quantal GABAergic transmission was altered only in the VB not the RTN. Immunostaining of vesicular GABA transporter showed opposite changes in the number of GABAergic synaptic terminals in the VB and RTN of Mecp2-null mice at P18–P20. The loss of MeCP2 had no significant effect on intrinsic properties of RTN neurons recorded at P15–P17. Our findings suggest that MeCP2 differentially regulates the development of GABAergic synapses in excitatory and inhibitory neurons in the thalamus.

P36. The role of FGF-signalling in osteosarcoma: A potential therapeutic target?

2008 ◽  
Vol 34 ◽  
pp. 26
Author(s):  
Daniel Weekes ◽  
Takeshi Kashima ◽  
Agamemnin Grigoriadis
Keyword(s):  
Therapeutic Target ◽  
Potential Therapeutic Target ◽  
Fgf Signalling

scholarly journals Fibroblast Growth Factor Signalling in the Diseased Nervous System

2021 ◽  
Author(s):  
Lars Klimaschewski ◽  
Peter Claus
Keyword(s):  
Nervous System ◽  
Imaging Techniques ◽  
Fibroblast Growth ◽  
Maintenance And Repair ◽  
Signalling Molecules ◽  
Mouse Mutants ◽  
Tissue Protection ◽  
Growth Factor Signalling ◽  
Fgf Signalling

AbstractFibroblast growth factors (FGFs) act as key signalling molecules in brain development, maintenance, and repair. They influence the intricate relationship between myelinating cells and axons as well as the association of astrocytic and microglial processes with neuronal perikarya and synapses. Advances in molecular genetics and imaging techniques have allowed novel insights into FGF signalling in recent years. Conditional mouse mutants have revealed the functional significance of neuronal and glial FGF receptors, not only in tissue protection, axon regeneration, and glial proliferation but also in instant behavioural changes. This review provides a summary of recent findings regarding the role of FGFs and their receptors in the nervous system and in the pathogenesis of major neurological and psychiatric disorders.

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