The teratogenic Veratrum alkaloid cyclopamine inhibits sonic hedgehog signal transduction

Development ◽  
1998 ◽  
Vol 125 (18) ◽  
pp. 3553-3562 ◽  
Author(s):  
J.P. Incardona ◽  
W. Gaffield ◽  
R.P. Kapur ◽  
H. Roelink
Keyword(s):  
Signal Transduction ◽  
Sonic Hedgehog ◽  
Neural Tube ◽  
Cholesterol Metabolism ◽  
Cell Types ◽  
Dependent Manner ◽  
Post Translational Modification ◽  
Shh Signaling ◽  
Exogenous Cholesterol ◽  
Ay 9944

The steroidal alkaloid cyclopamine produces cyclopia and holoprosencephaly when administered to gastrulation-stage amniote embryos. Cyclopamine-induced malformations in chick embryos are associated with interruption of Sonic hedgehog (Shh)-mediated dorsoventral patterning of the neural tube and somites. Cell types normally induced in the ventral neural tube by Shh are either absent or appear aberrantly at the ventral midline after cyclopamine treatment, while dorsal cell types normally repressed by Shh appear ventrally. Somites in cyclopamine-treated embryos show Pax7 expression throughout, indicating failure of sclerotome induction. Cyclopamine at concentrations of 20–100 nM blocks the response of neural plate explants to recombinant Shh-N in a dose-dependent manner. Similar concentrations have no effect on the post-translational modification of Shh by cholesterol in transfected COS-1 cells. Comparison of the effects of cyclopamine to those of the holoprosencephaly-inducing cholesterol synthesis inhibitor AY-9944 shows that cyclopamine does not induce malformations by interfering with cholesterol metabolism. Although AY-9944 does not interrupt Shh signaling in ovo, it blocks the response to Shh-N in explants cultured without an exogenous cholesterol source. As predicted by current models of the regulation of cholesterol metabolism, the response to Shh-N in AY-9944-treated explants is restored by providing exogenous cholesterol. However, exogenous cholesterol does not restore Shh signaling in cyclopamine-treated explants. These findings suggest that cyclopamine-induced teratogenesis is due to a more direct antagonism of Shh signal transduction.

scholarly journals Ciliary phosphatidylinositol phosphatase Inpp5e plays positive and negative regulatory roles in Shh signaling

2019 ◽  
Author(s):  
Sandii Constable ◽  
Alyssa B. Long ◽  
Katharine A. Floyd ◽  
Stéphane Schurmans ◽  
Tamara Caspary
Keyword(s):  
Signal Transduction ◽  
Sonic Hedgehog ◽  
Neural Tube ◽  
Relative Timing ◽  
Neural Patterning ◽  
Cell Fates ◽  
Shh Signaling ◽  
Mouse Mutants ◽  
Summary Statement ◽  
Time Required

AbstractSonic hedgehog (Shh) signal transduction specifies ventral cell fates in the neural tube and is mediated by the Gli transcription factors that play both activator (GliA) and repressor (GliR) roles. Cilia are essential for Shh signal transduction and the ciliary phosphatidylinositol phosphatase, Inpp5e, is linked to Shh regulation. In the course of a forward genetic screen for recessive mouse mutants, we identified a functional null allele of Inpp5e, ridge top (rdg), with expanded ventral neural cell fates at E10.5. By E12.5, Inpp5erdg/rdg embryos displayed normal neural patterning and this correction over time required Gli3, the predominant repressor in neural patterning. Inpp5erdg function largely depended on the presence of cilia and on Smoothened, the obligate transducer of Shh signaling, indicating Inpp5e functions within the cilium to regulate the pathway. These data indicate that Inpp5e plays a more complicated role in Shh signaling than previously appreciated. We propose that Inpp5e attenuates Shh signaling in the neural tube through regulation of the relative timing of GliA and GliR production, which is important in understanding how duration of Shh signaling regulates neural tube patterning.Summary statementInpp5e attenuates Sonic hedgehog signal transduction through a combination of positive and negative regulatory roles that likely control the relative timing of Gli processing.

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.

Sonic hedgehog signaling at gastrula stages specifies ventral telencephalic cells in the chick embryo

Development ◽  
2000 ◽  
Vol 127 (15) ◽  
pp. 3283-3293 ◽  
Author(s):  
L. Gunhaga ◽  
T.M. Jessell ◽  
T. Edlund
Keyword(s):  
Sonic Hedgehog ◽  
Neural Tube ◽  
Hedgehog Signaling ◽  
Early Stage ◽  
Primitive Streak ◽  
Cell Types ◽  
Neural Cells ◽  
Sonic Hedgehog Signaling ◽  
Ventral Telencephalon ◽  
Prechordal Mesoderm

A secreted signaling factor, Sonic hedgehog (Shh), has a crucial role in the generation of ventral cell types along the entire rostrocaudal axis of the neural tube. At caudal levels of the neuraxis, Shh is secreted by the notochord and floor plate during the period that ventral cell fates are specified. At anterior prosencephalic levels that give rise to the telencephalon, however, neither the prechordal mesoderm nor the ventral neural tube expresses Shh at the time that the overt ventral character of the telencephalon becomes evident. Thus, the precise role and timing of Shh signaling relevant to the specification of ventral telencephalic identity remains unclear. By analysing neural cell differentiation in chick neural plate explants we provide evidence that neural cells acquire molecular properties characteristic of the ventral telencephalon in response to Shh signals derived from the anterior primitive streak/Hensen's node region at gastrula stages. Exposure of prospective anterior prosencephalic cells to Shh at this early stage is sufficient to initiate a temporal program of differentiation that parallels that of neurons generated normally in the medial ganglionic eminence subdivision of the ventral telencephalon.

Zebrafishsmoothenedfunctions in ventral neural tube specification and axon tract formation

Development ◽  
2001 ◽  
Vol 128 (18) ◽  
pp. 3497-3509 ◽  
Author(s):  
Zoltán M. Varga ◽  
Angel Amores ◽  
Katharine E. Lewis ◽  
Yi-Lin Yan ◽  
John H. Postlethwait ◽  
...  
Keyword(s):  
Sonic Hedgehog ◽  
Neural Tube ◽  
Hedgehog Signaling ◽  
Floor Plate ◽  
Slow Muscle ◽  
Pituitary Cells ◽  
Shh Signaling ◽  
Ventral Neural Tube ◽  
Hypothalamic Cells

Sonic hedgehog (Shh) signaling patterns many vertebrate tissues. shh mutations dramatically affect mouse ventral forebrain and floor plate but produce minor defects in zebrafish. Zebrafish have two mammalian Shh orthologs, sonic hedgehog and tiggy-winkle hedgehog, and another gene, echidna hedgehog, that could have overlapping functions. To examine the role of Hedgehog signaling in zebrafish, we have characterized slow muscle omitted (smu) mutants. We show that smu encodes a zebrafish ortholog of Smoothened that transduces Hedgehog signals. Zebrafish smoothened is expressed maternally and zygotically and supports specification of motoneurons, pituitary cells and ventral forebrain. We propose that smoothened is required for induction of lateral floor plate and a subpopulation of hypothalamic cells and for maintenance of medial floor plate and hypothalamic cells.

scholarly journals Sonic hedgehog signaling pathway promotes pancreatic cancer pain via nerve growth factor

2019 ◽  
Vol 45 (2) ◽  
pp. 137-144 ◽  
Author(s):  
Liang Han ◽  
Jie Jiang ◽  
Mengwen Xue ◽  
Tao Qin ◽  
Ying Xiao ◽  
...  
Keyword(s):  
Pancreatic Cancer ◽  
Nerve Growth Factor ◽  
Growth Factor ◽  
Signaling Pathway ◽  
Sonic Hedgehog ◽  
Dependent Manner ◽  
Nude Mouse Model ◽  
Shh Signaling ◽  
Nerve Growth ◽  
Rna Transfection

Background Many patients with pancreatic cancer (PC) suffer from abdominal pain and back pain. However, the cause of pain associated with PC is largely unclear. In this study, we tested the potential influence of the sonic hedgehog (sHH) signaling pathway on PC pain. Methods Substance P (SP) and calcitonin gene-related peptide (CGRP) expression was measured in cultured PC cells and dorsal root ganglions (DRG) by real-time PCR, western blotting analysis and ELISA. Small interfering RNA transfection and plasmid constructs were used to regulate the expression of sHH in the AsPc-1 and Panc-1 cell lines. Pain-related behavior was observed in an orthotopic tumor model in nude mice. Results In this study, the results show that sHH increased the expression of SP and CGRP in DRGs in a concentration and time-dependent manner. Additionally, sHH secretion from PC cells could activate the sHH signaling pathway and, in turn, increase the expression of nerve growth factor (NGF), P75, and TrkA in DRGs. Furthermore, the sHH signaling pathway and NGF/NGF receptor contributed to pain sensitivity in a nude mouse model. Conclusion Our results demonstrate that PC pain originates from the sHH signaling pathway, and NGF mediates the pain mechanism via regulating SP and CGRP.

scholarly journals THU0076 SONIC HEDGEHOG PROMOTES SYNOVIAL HYPERPLASIA AND BONE DAMAGE THROUGH P38 MAPK SIGNALING IN EXPERIMENTAL ARTHRITIS

2020 ◽  
Vol 79 (Suppl 1) ◽  
pp. 250.1-251
Author(s):  
S. Zhu ◽  
Y. Shi ◽  
Y. Ye ◽  
X. Feng ◽  
J. Huang
Keyword(s):  
P38 Mapk ◽  
Sonic Hedgehog ◽  
Bone Erosion ◽  
Cartilage Damage ◽  
Mapk Signaling ◽  
Experimental Arthritis ◽  
Dependent Manner ◽  
Shh Signaling ◽  
Synovial Hyperplasia ◽  
Bone Damage

Background:Abnormal activation of sonic hedgehog (SHH) signaling has been found in synovium from patients with rheumatoid arthritis (RA). Inhibition of SHH signaling is reported to attenuate inflammation and cartilage damage in adjuvant-induced arthritis (AIA). Previously we have demonstrated that SHH signaling promoted the tumor-like behavior of fibroblast-like synoviocytes (FLSs) through p38 MAPKin vitro.Objectives:In the current study, we aim to further explore the role of SHH-p38 MAPK signaling in regulating synovial hyperplasia and bone erosion in experimental arthritis.Methods:Collagen-induced arthritis (CIA) mouse model was induced and the mice were injected with adenovirus associated virus (AAV) overexpressing SHH or treated with small molecule inhibitors GDC-0449. SB203580 was administrated for the inhibition of p38 MAPK. The severity of paw inflammation was graded and serum levels of TNFα, IL-6 were detected. The histological features of arthritis were evaluated by H&E staining. The bone erosion was identified by micro-CT assessment and the number and function of osteoclasts were determined.Results:Blockade of SHH by GDC-0449 significantly alleviated the symptoms and decreased the synovial hyperplasia, inflammatory infiltration, cartilage and bone damage in ankles of CIA. The bone erosions in the area of the metatarsophalangeal and ankle joints and production of TNFα, IL-6 were decreased by SHH inhibition. In addition, the administration of GDC-0449 significantly decreased the number of TRAP positive cells and the expression of NFATc1. On the contrary, SHH overexpression led to increased severity of arthritis and pathological changes. We also observed the accelerated bone injury accompanied with increased number and activity of osteoclasts and increased production of serum IL-6 in mice with upregulation of SHH expression. Of note, the administration of p38 MAPK inhibitor reversed the effects of SHH overexpression, with a reduction of joint swelling and histological scores. Inhibition of p38 MAPK prevented the bone erosion and decreased the number of TRAP positive cells and the expression of NFATc1, which were promoted by SHH overexpression.Conclusion:The study indicates that SHH promotes the synovial hyperplasia and bone erosion of CIA in a p38 MAPK-dependent manner. SHH-p38 MAPK signaling could be a potential target for the treatment of RA.Acknowledgments:This work was supported by grants from the National Natural Science Foundation of China (81571584, 81701609).Disclosure of Interests:None declared

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

eLife ◽  
2020 ◽  
Vol 9 ◽  
Author(s):  
Eric R Brooks ◽  
Mohammed Tarek 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

Neural 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 flat 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.

Role of M402, a novel heparan sulfate mimetic, in pancreatic cancer cell invasion and metastasis: Inhibition of the Sonic Hedgehog pathway and heparanase activity.

2012 ◽  
Vol 30 (30_suppl) ◽  
pp. 25-25 ◽  
Author(s):  
Zoya Galcheva-Gargova ◽  
Chia Lin Chu ◽  
Alison Long ◽  
Jay Duffner ◽  
Kimberly Holte ◽  
...  
Keyword(s):  
Pancreatic Cancer ◽  
Sonic Hedgehog ◽  
Size Structure ◽  
Clinical Investigation ◽  
Tumor Stroma ◽  
Dependent Manner ◽  
Shh Signaling ◽  
Shh Pathway ◽  
Heparin Sulfate

25 Background: M402 is a novel heparin sulfate mimetic that binds to multiples growth factors, adhesion molecules, and cytokines to inhibit tumor angiogenesis, progression, and metastasis in nonclinical studies. We investigated if M402 could modulate tumor-stroma interactions in pancreatic cancer by inhibiting the Sonic Hedgehog (Shh) pathway as well as inhibit the activity of the extracellular matrix degrading enzyme, heparanase. Methods: Surface plasmon resonance (SPR) was used for analysis of M402 binding to Shh in vitro. A cell based Gli-1 reporter assay was implemented to assess the effect of M402 on Shh signaling. Immunohistochemistry and RT-qPCR were utilized to investigate M402’s effect on Shh activity in an orthotopic Capan-2 model in nude mice. The effect of M402 on heparanase activity in vitro and on Capan-2 tumor samples isolated from treated and untreated mice was measured using an HTRF-FRET assay. Results: There was specific binding of M402 to Shh in vitro. Additionally, Shh signaling was inhibited in the presence of M402. Immunohistochemistry and RT-qPCR of Capan-2 tumor samples from animals treated with M402 also demonstrated reduction of Shh signaling via Gli, its targeted transcription factor. The degree of inhibition of heparanase activity, as measured in the HTRF assay, was affected by the size, structure, and sulfation pattern of the different heparin sulfate mimetics evaluated. M402 was the most potent inhibitor of heparanse activity in vitro from all compounds tested. In addition, treatment with M402 inhibited heparanase activity in the pancreatic tumor lysates in a dose-dependent manner. Conclusions: M402 was shown in nonclinical studies to modulate tumor-stroma interactions involved in the metastatic, invasive, and desmoplastic pathways by simultaneously inhibiting two distinct pathways: Shh signaling and the activity of heparanase. M402 regulates a variety of polysaccharide-based binding proteins, which provides a rationale for the clinical investigation of M402 in a range of cancers.

Spindle scaling mechanisms

2020 ◽  
Vol 64 (2) ◽  
pp. 383-396
Author(s):  
Lara K. Krüger ◽  
Phong T. Tran
Keyword(s):  
Cell Size ◽  
Spindle Assembly ◽  
Dependent Manner ◽  
Post Translational Modification ◽  
Size Dependent ◽  
A Cell ◽  
Chromosome Separation ◽  
Spindle Elongation ◽  
Protein Gradients ◽  
Spindle Structure

Abstract The mitotic spindle robustly scales with cell size in a plethora of different organisms. During development and throughout evolution, the spindle adjusts to cell size in metazoans and yeast in order to ensure faithful chromosome separation. Spindle adjustment to cell size occurs by the scaling of spindle length, spindle shape and the velocity of spindle assembly and elongation. Different mechanisms, depending on spindle structure and organism, account for these scaling relationships. The limited availability of critical spindle components, protein gradients, sequestration of spindle components, or post-translational modification and differential expression levels have been implicated in the regulation of spindle length and the spindle assembly/elongation velocity in a cell size-dependent manner. In this review, we will discuss the phenomenon and mechanisms of spindle length, spindle shape and spindle elongation velocity scaling with cell size.

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