Dorsoventral patterning is established in the telencephalon of mutants lacking both Gli3 and Hedgehog signaling

Development ◽  
2002 ◽  
Vol 129 (21) ◽  
pp. 4963-4974 ◽  
Author(s):  
Murielle Rallu ◽  
Robert Machold ◽  
Nicholas Gaiano ◽  
Joshua G. Corbin ◽  
Andrew P. McMahon ◽  
...  
Keyword(s):  
Nervous System ◽  
Sonic Hedgehog ◽  
Hedgehog Signaling ◽  
Genetic Interaction ◽  
Null Mutant ◽  
Dorsoventral Patterning ◽  
Wild Type ◽  
Shh Signaling ◽  
Necessary And Sufficient ◽  
Regional Character

Considerable data suggest that sonic hedgehog (Shh) is both necessary and sufficient for the specification of ventral pattern throughout the nervous system, including the telencephalon. We show that the regional markers induced by Shh in the E9.0 telencephalon are dependent on the dorsoventral and anteroposterior position of ectopic Shh expression. This suggests that by this point in development regional character in the telencephalon is established. To determine whether this prepattern is dependent on earlier Shh signaling, we examined the telencephalon in mice carrying either Shh- orGli3-null mutant alleles. This analysis revealed that the expression of a subset of ventral telencephalic markers, including Dlx2 andGsh2, although greatly diminished, persist inShh-/- mutants, and that these same markers were expanded in Gli3-/- mutants. To understand further the genetic interaction between Shh and Gli3, we examined Shh/Gli3 andSmoothened/Gli3 double homozygous mutants. Notably, in animals carrying either of these genetic backgrounds, genes such as Gsh2 andDlx2, which are expressed pan-ventrally, as well as Nkx2.1,which demarcates the ventral most aspect of the telencephalon, appear to be largely restored to their wild-type patterns of expression. These results suggest that normal patterning in the telencephalon depends on the ventral repression of Gli3 function by Shh and, conversely, on the dorsal repression of Shh signaling by Gli3. In addition these results support the idea that, in addition to hedgehog signaling, a Shh-independent pathways must act during development to pattern the telencephalon.

scholarly journals Sonic hedgehog signaling in astrocytes

2020 ◽  
Author(s):  
Steven A. Hill ◽  
Marissa Fu ◽  
A. Denise R. Garcia
Keyword(s):  
Nervous System ◽  
Signaling Pathway ◽  
Functional Properties ◽  
Sonic Hedgehog ◽  
Hedgehog Signaling ◽  
Synapse Formation ◽  
Synaptic Activity ◽  
Molecular Signaling ◽  
Sonic Hedgehog Signaling ◽  
Shh Signaling

Abstract Astrocytes are complex cells that perform a broad array of essential functions in the healthy and injured nervous system. The recognition that these cells are integral components of various processes, including synapse formation, modulation of synaptic activity, and response to injury, underscores the need to identify the molecular signaling programs orchestrating these diverse functional properties. Emerging studies have identified the Sonic hedgehog (Shh) signaling pathway as an essential regulator of the molecular identity and functional properties of astrocytes. Well established as a powerful regulator of diverse neurodevelopmental processes in the embryonic nervous system, its functional significance in astrocytes is only beginning to be revealed. Notably, Shh signaling is active only in discrete subpopulations of astrocytes distributed throughout the brain, a feature that has potential to yield novel insights into functional specialization of astrocytes. Here, we discuss Shh signaling and emerging data that point to essential roles for this pleiotropic signaling pathway in regulating various functional properties of astrocytes in the healthy and injured brain.

scholarly journals Distinct temporal requirements for Sonic hedgehog signaling in development of the tuberal hypothalamus

2018 ◽  
Author(s):  
Tanya S. Corman ◽  
Solsire E. Zevallos ◽  
Douglas J. Epstein
Keyword(s):  
Sonic Hedgehog ◽  
Hedgehog Signaling ◽  
Brain Area ◽  
Early Time ◽  
Cellular Heterogeneity ◽  
Fate Mapping ◽  
Dorsoventral Patterning ◽  
Sonic Hedgehog Signaling ◽  
Shh Signaling ◽  
Conditional Deletion

ABSTRACTSonic hedgehog (Shh) plays well characterized roles in the development of several regions of the brain and spinal cord, but its functions in the hypothalamus have been more difficult to elucidate due to the complex neuroanatomy of this brain area. Here, we utilize fate-mapping and conditional deletion models in mice to define requirements for dynamic Shh activity at distinct stages of tuberal hypothalamic development, a brain region with important homeostatic functions. At early time points, Shh signaling regulates dorsoventral patterning, neurogenesis, and the size of the ventral midline. Fate mapping experiments demonstrate that Shh expressing and responsive progenitors contribute to distinct neuronal subtypes, accounting for some of the cellular heterogeneity in tuberal hypothalamic nuclei. Conditional deletion of the Hedgehog transducer Smoothened (Smo), after dorsoventral patterning has been established, reveals that Shh signaling is necessary to maintain proliferation and progenitor identity during peak periods of hypothalamic neurogenesis. We also find that mosaic disruption of Smo causes a non-cell autonomous gain in Shh signaling activity in neighboring wild type cells, suggesting a mechanism for the pathogenesis of hypothalamic hamartomas, a benign tumor that forms during hypothalamic development.SUMMARY STATEMENTRequirements for dynamic Sonic hedgehog activity at distinct stages of tuberal hypothalamic development are defined using fate-mapping and conditional deletion models in mice.

scholarly journals Baicalin improves the in vitro developmental capacity of pig embryos by inhibiting apoptosis, regulating mitochondrial activity and activating sonic hedgehog signaling

2019 ◽  
Vol 25 (9) ◽  
pp. 538-549 ◽  
Author(s):  
Qing Guo ◽  
Mei-Fu Xuan ◽  
Zhao-Bo Luo ◽  
Jun-Xia Wang ◽  
Sheng-Zhong Han ◽  
...  
Keyword(s):  
Embryonic Development ◽  
Signaling Pathway ◽  
Sonic Hedgehog ◽  
Hedgehog Signaling ◽  
Control Group ◽  
Mitochondrial Activity ◽  
Cell Stage ◽  
Shh Signaling ◽  
Developmental Capacity

Abstract Baicalin, a traditional Chinese medicinal monomer whose chemical structure is known, can be used to treat female infertility. However, the effect of baicalin on embryonic development is unknown. This study investigated the effects of baicalin on in vitro development of parthenogenetically activated (PA) and in vitro fertilized (IVF) pig embryos and the underlying mechanisms involved. Treatment with 0.1 μg/ml baicalin significantly improved (P < 0.05) the in vitro developmental capacity of PA pig embryos by reducing the reactive oxygen species (ROS) levels and apoptosis and increasing the mitochondrial membrane potential (ΔΨm) and ATP level. mRNA and protein expression of sonic hedgehog (SHH) and GLI1, which are related to the SHH signaling pathway, in PA pig embryos at the 2-cell stage, were significantly higher in the baicalin-treated group than in the control group. To confirm that the SHH signaling pathway is involved in the mechanism by which baicalin improves embryonic development, we treated embryos with baicalin in the absence or presence of cyclopamine (Cy), an inhibitor of this pathway. Cy abolished the effects of baicalin on in vitro embryonic development. In conclusion, baicalin improves the in vitro developmental capacity of PA and IVF pig embryos by inhibiting ROS production and apoptosis, regulating mitochondrial activity and activating SHH signaling.

scholarly journals Sonic hedgehog signaling directs patterned cell remodeling during cranial neural tube closure

2020 ◽  
Author(s):  
Eric R. Brooks ◽  
Mohammed T. Islam ◽  
Kathryn V. Anderson ◽  
Jennifer A. Zallen
Keyword(s):  
Sonic Hedgehog ◽  
Neural Tube ◽  
Hedgehog Signaling ◽  
Structural Changes ◽  
Neural Tube Closure ◽  
Mammalian Brain ◽  
Shh Signaling ◽  
Apical Constriction ◽  
Cell Remodeling ◽  
Tube Closure

AbstractNeural tube closure defects are a major cause of infant mortality, with exencephaly accounting for nearly one-third of cases. However, the mechanisms of cranial neural tube closure are not well understood. Here we show that this process involves a tissue-wide pattern of apical constriction controlled by Sonic hedgehog (Shh) signaling. Midline cells in the mouse midbrain neuroepithelium are short with large apical surfaces, whereas lateral cells are taller and undergo synchronous apical constriction, driving neural fold elevation. Embryos lacking the Shh effector Gli2 fail to produce appropriate midline cell architecture, whereas embryos with expanded Shh signaling, including the IFT-A complex mutants Ift122 and Ttc21b and embryos expressing activated Smoothened, display apical constriction defects in lateral cells. Disruption of lateral, but not midline, cell remodeling results in exencephaly. These results reveal a morphogenetic program of patterned apical constriction governed by Shh signaling that generates structural changes in the developing mammalian brain.

scholarly journals ARL13B regulates Sonic Hedgehog signaling from outside primary cilia

2019 ◽  
Author(s):  
Eduardo D. Gigante ◽  
Megan R. Taylor ◽  
Anna A. Ivanova ◽  
Richard A. Kahn ◽  
Tamara Caspary
Keyword(s):  
Signal Transduction ◽  
Sonic Hedgehog ◽  
Protein Trafficking ◽  
Hedgehog Signaling ◽  
Primary Cilia ◽  
Complete Loss ◽  
Wild Type ◽  
Sonic Hedgehog Signaling ◽  
Biochemical Function

AbstractARL13B is a regulatory GTPase highly enriched in cilia. Complete loss of Arl13b disrupts cilia architecture, protein trafficking and Sonic hedgehog signaling. To determine whether ARL13B is required within cilia, we knocked in a cilia-excluded variant of ARL13B (V358A) and showed it retains all known biochemical function. We found that ARL13BV358A protein was expressed but could not be detected in cilia, even when retrograde ciliary transport was blocked. We showed Arl13bV358A/V358A mice are viable and fertile with normal Shh signal transduction. However, in contrast to wild type cilia, Arl13bV358A/V358A cells displayed short cilia and lacked ciliary ARL3 and INPP5E. These data indicate that ARL13B’s role within cilia can be uncoupled from its function outside of cilia. Furthermore, these data imply that the cilia defects upon complete absence of ARL13B do not underlie the alterations in Shh transduction, which is unexpected given the requirement of cilia for Shh transduction.

scholarly journals ARL13B regulates Sonic hedgehog signaling from outside primary cilia

eLife ◽  
2020 ◽  
Vol 9 ◽  
Author(s):  
Eduardo D Gigante ◽  
Megan R Taylor ◽  
Anna A Ivanova ◽  
Richard A Kahn ◽  
Tamara Caspary
Keyword(s):  
Signal Transduction ◽  
Sonic Hedgehog ◽  
Protein Trafficking ◽  
Hedgehog Signaling ◽  
Primary Cilia ◽  
Complete Loss ◽  
Wild Type ◽  
Sonic Hedgehog Signaling ◽  
Biochemical Function

ARL13B is a regulatory GTPase highly enriched in cilia. Complete loss of Arl13b disrupts cilia architecture, protein trafficking and Sonic hedgehog signaling. To determine whether ARL13B is required within cilia, we knocked in a cilia-excluded variant of ARL13B (V358A) and showed it retains all known biochemical function. We found that ARL13BV358A protein was expressed but could not be detected in cilia, even when retrograde ciliary transport was blocked. We showed Arl13bV358A/V358A mice are viable and fertile with normal Shh signal transduction. However, in contrast to wild type cilia, Arl13bV358A/V358A cells displayed short cilia and lacked ciliary ARL3 and INPP5E. These data indicate that ARL13B’s role within cilia can be uncoupled from its function outside of cilia. Furthermore, these data imply that the cilia defects upon complete absence of ARL13B do not underlie the alterations in Shh transduction, which is unexpected given the requirement of cilia for Shh transduction.

scholarly journals Sonic hedgehog signaling in epithelial tissue development

2019 ◽  
Vol 7 ◽  
pp. 3
Author(s):  
Lu Zheng ◽  
Chen Rui ◽  
Hao Zhang ◽  
Jing Chen ◽  
Xiuzhi Jia ◽  
...  
Keyword(s):  
Signaling Pathway ◽  
Sonic Hedgehog ◽  
Hedgehog Signaling ◽  
Gastric Epithelium ◽  
Epithelial Tissue ◽  
Sonic Hedgehog Signaling ◽  
Shh Signaling ◽  
Shh Pathway ◽  
Tissue Repair And Regeneration ◽  
New Treatment

The Sonic hedgehog (SHH) signaling pathway is essential for embryonic development and tissue regeneration. The dysfunction of SHH pathway is involved in a variety of diseases, including cancer, birth defects, and other diseases. Here we reviewed recent studies on main molecules involved in the SHH signaling pathway, specifically focused on their function in epithelial tissue and appendages development, including epidermis, touch dome, hair, sebaceous gland, mammary gland, tooth, nail, gastric epithelium, and intestinal epithelium. The advance in understanding the SHH signaling pathway will give us more clues to the mechanisms of tissue repair and regeneration, as well as the development of new treatment for diseases related to dysregulation of SHH signaling pathway.

FoxF1 is Required for Ciliogenesis and Distribution of Sonic Hedgehog Signaling Components in Cilium

2019 ◽  
Vol 19 (5) ◽  
pp. 326-334
Author(s):  
Lu Huang ◽  
Marco Tjakra ◽  
Desha Luo ◽  
Lin Wen ◽  
Daoxi Lei ◽  
...  
Keyword(s):  
Sonic Hedgehog ◽  
Hedgehog Signaling ◽  
3T3 Cells ◽  
Shh Signaling ◽  
Nih 3T3 ◽  
Signaling Components ◽  
Nih 3T3 Cells

Background: In vertebrates, cilium is crucial for Hedgehog signaling transduction. Forkhead box transcriptional factor FoxF1 is reported to be associated with Sonic Hedgehog (Shh) signaling in many cases. However, the role of FoxF1 in cilium remains unknown. Here, we showed an essential role of FoxF1 in the regulation of ciliogenesis and in the distribution of Shh signaling components in cilium. Methods: NIH/3T3 cells were serum starved for 24h to induce cilium. Meanwhile, shRNA was used to knockdown the FoxF1 expression in the cells and CRISPR/Cas9 was used to generate the FoxF1 zebrafish mutant. The mRNA and protein expression of indicated genes were detected by the qRT-PCR and western blot, respectively. Immunofluorescence staining was performed to detect the cilium and Shh components distribution. Results: FoxF1 knockdown decreased the cilium length in NIH/3T3 cells. Meanwhile, the disruption of FoxF1 function inhibited the expression of cilium-related genes and caused an abnormal distribution of Shh components in the cilium. Furthermore, homozygous FoxF1 mutants exhibited defective development of pronephric cilium in early zebrafish embryos. Conclusion: Together, our data illustrated that FoxF1 is required for ciliogenesis in vitro and in vivo and for the proper localization of Shh signaling components in cilium.

Cancer Stem Cells Equipped with Powerful Hedgehog Signaling and Better Epigenetic Memory: Avenues to Look for Cancer Therapeutics

2019 ◽  
Vol 19 (11) ◽  
pp. 877-884 ◽  
Author(s):  
Ishita Tandon ◽  
Asawari Waghmode ◽  
Nilesh Kumar Sharma
Keyword(s):  
Stem Cells ◽  
Cancer Stem Cells ◽  
Sonic Hedgehog ◽  
Hedgehog Signaling ◽  
Cancer Therapeutics ◽  
Complex Nature ◽  
Epigenetic Memory ◽  
Therapeutic Approaches ◽  
Shh Signaling ◽  
Memory Power

Complex nature of the tumor is depicted at the cellular landscape by showing heterogeneity in the presence of cancer cells, cancer-associated stromal cells, mesenchymal stem cells and cancer stem cells (CSCs). One of the plausible views in cancer formation is suggested as the theory of cancer CSCs that is known as a source of initiation of tumorigenesis. In essence, these powerful CSCs are equipped with high Sonic Hedgehog (SHH) signaling and epigenetic memory power that support various tumor hallmarks. Truly, nature justifies its intent by limiting these stem cells with a potential to turn into CSCs and in turn suppressing the high risk of humans and other organisms. In short, this mini-review addresses the contribution of SHH signaling to allow reprogramming of epigenetic memory within CSCs that support tumor hallmarks. Besides, this paper explores therapeutic approaches to mitigate SHH signaling that may lead to a blockade of the pro-tumor potential of CSCs.

Sign in / Sign up

Export Citation Format

Share Document