scholarly journals Lipoproteins carry endocannabinoids that inhibit the Hedgehog pathway

2013 ◽  
Author(s):  
Helena Khaliullina ◽  
Mesut Bilgin ◽  
Julio L. Sampaio ◽  
Andrej Shevchenko ◽  
Suzanne Eaton
Keyword(s):  
Mass Spectrometry ◽  
Hedgehog Signaling ◽  
Hedgehog Signaling Pathway ◽  
Cubitus Interruptus ◽  
Drosophila Wing ◽  
Lipid Mass ◽  
Biochemical Fractionation ◽  
Wing Imaginal Discs ◽  
Hedgehog Proteins

Hedgehog proteins are lipid-modified secreted signaling molecules that regulate tissue development and homeostasis. Lipids contained in circulating lipoproteins repress the Hedgehog signaling pathway in the absence of Hedgehog ligand, but the identity of these lipids is unknown. Here, using biochemical fractionation and lipid mass spectrometry, we identify these inhibitory lipids as endocannabinoids. Endocannabinoids are present in lipoproteins of both flies and humans, and repress the pathway in both mammalian signaling assays and Drosophila wing imaginal discs. In Drosophila, endocannabinoids are required in vivo to keep the levels of Smoothened and full-length Cubitus interruptus (Ci155) low in the absence of Hedgehog. Furthermore, elevating their endogenous levels inhibits Hedgehog-dependent accumulation of Smoothened and Ci155. Interestingly, cannabis-derived phytocannabinoids are also potent pathway inhibitors in flies and mammals. These findings constitute a novel link between organismal metabolism and local Hedgehog signaling, and suggest previously unsuspected mechanisms for the broad physiological activities of cannabinoids.

scholarly journals Endocannabinoids are conserved inhibitors of the Hedgehog pathway

2015 ◽  
Vol 112 (11) ◽  
pp. 3415-3420 ◽  
Author(s):  
Helena Khaliullina ◽  
Mesut Bilgin ◽  
Julio L. Sampaio ◽  
Andrej Shevchenko ◽  
Suzanne Eaton
Keyword(s):  
Mass Spectrometry ◽  
Hedgehog Signaling ◽  
Transmembrane Protein ◽  
Hedgehog Pathway ◽  
Tissue Development ◽  
Control Tissue ◽  
Lipid Mass ◽  
Biochemical Fractionation

Hedgehog ligands control tissue development and homeostasis by alleviating repression of Smoothened, a seven-pass transmembrane protein. The Hedgehog receptor, Patched, is thought to regulate the availability of small lipophilic Smoothened repressors whose identity is unknown. Lipoproteins contain lipids required to repress Smoothened signaling in vivo. Here, using biochemical fractionation and lipid mass spectrometry, we identify these repressors as endocannabinoids. Endocannabinoids circulate in human and Drosophila lipoproteins and act directly on Smoothened at physiological concentrations to repress signaling in Drosophila and mammalian assays. Phytocannabinoids are also potent Smo inhibitors. These findings link organismal metabolism to local Hedgehog signaling and suggest previously unsuspected mechanisms for the physiological activities of cannabinoids.

scholarly journals The PI3K Inhibitor XH30 Enhances Response to Temozolomide in Drug-Resistant Glioblastoma via the Noncanonical Hedgehog Signaling Pathway

2021 ◽  
Vol 12 ◽  
Author(s):  
Ming Ji ◽  
Zhihui Zhang ◽  
Songwen Lin ◽  
Chunyang Wang ◽  
Jing Jin ◽  
...  
Keyword(s):  
Signaling Pathway ◽  
Hedgehog Signaling ◽  
Kinase Inhibitor ◽  
Therapeutic Option ◽  
Hedgehog Signaling Pathway ◽  
Orthotopic Mouse Model ◽  
Cycle Arrest ◽  
The Central Nervous System

Glioblastoma multiforme (GBM) is the most common malignant tumor of the central nervous system. Temozolomide (TMZ)–based adjuvant treatment has improved overall survival, but clinical outcomes remain poor; TMZ resistance is one of the main reasons for this. Here, we report a new phosphatidylinositide 3-kinase inhibitor, XH30; this study aimed to assess the antitumor activity of this compound against TMZ-resistant GBM. XH30 inhibited cell proliferation in TMZ-resistant GBM cells (U251/TMZ and T98G) and induced cell cycle arrest in the G1 phase. In an orthotopic mouse model, XH30 suppressed TMZ-resistant tumor growth. XH30 was also shown to enhance TMZ cytotoxicity both in vitro and in vivo. Mechanistically, the synergistic effect of XH30 may be attributed to its repression of the key transcription factor GLI1 via the noncanonical hedgehog signaling pathway. XH30 reversed sonic hedgehog–triggered GLI1 activation and decreased GLI1 activation by insulin-like growth factor 1 via the noncanonical hedgehog signaling pathway. These results indicate that XH30 may represent a novel therapeutic option for TMZ-resistant GBM.

Role of knot (kn) in Wing Patterning in Drosophila

Genetics ◽  
1997 ◽  
Vol 147 (3) ◽  
pp. 1203-1212 ◽  
Author(s):  
Katerina Nestoras ◽  
Helena Lee ◽  
Jym Mohler
Keyword(s):  
Hedgehog Signaling ◽  
Imaginal Disc ◽  
Hedgehog Signaling Pathway ◽  
Posterior Compartment ◽  
Drosophila Wing ◽  
Compartment Boundary ◽  
Hh Signaling ◽  
Embryonic Segmentation ◽  
Anterior Posterior

We have undertaken a genetic analysis of new strong alleles of knot (kn). The original kn1 mutation causes an alteration of wing patterning similar to that associated with mutations of fused (fu), an apparent fusion of veins 3 and 4 in the wing. However, unlike fu, strong kn mutations do not affect embryonic segmentation and indicate that kn is not a component of a general Hh (Hedgehog)-signaling pathway. Instead we find that kn has a specific role in those cells of the wing imaginal disc that are subject to ptc-mediated Hh-signaling. Our results suggest a model for patterning the medial portion of the Drosophila wing, whereby the separation of veins 3 and 4 is maintained by kn activation in the intervening region in response to Hh-signaling across the adjacent anterior-posterior compartment boundary.

scholarly journals Hherisomes, hedgehog specialized recycling endosomes, are required for high level hedgehog signaling and tissue growth

2021 ◽  
Author(s):  
Sandrine Pizette ◽  
Tamás Matusek ◽  
Bram Herpers ◽  
Pascal P. Thérond ◽  
Catherine Rabouille
Keyword(s):  
Hedgehog Signaling ◽  
Wing Disc ◽  
Tissue Growth ◽  
Small Gtpase ◽  
Recycling Endosomes ◽  
Drosophila Wing ◽  
Immuno Electron Microscopy ◽  
Wing Imaginal Discs ◽  
Hh Signaling ◽  
High Level

In metazoans, tissue growth and patterning is partly controlled by the Hedgehog (Hh) morphogen. Using immuno-electron microscopy on Drosophila wing imaginal discs, we identified a cellular structure, the Hherisomes that contain the majority of intracellular Hh. Hherisomes are recycling tubular endosomes and their formation is specifically boosted by overexpression of Hh. Expression of Rab11, a small GTPase involved in recycling endosomes, boosts the size of Hherisomes and their Hh concentration. Conversely, increased expression of the transporter Dispatched, a regulator of Hh secretion, leads to their clearance. We show that increasing Hh density in Hherisomes through Rab11 overexpression enhances both the level of Hh-signaling and disc pouch growth, whereas Dispatched overexpression decreases high level Hh-signaling and growth. We propose that upon secretion, a pool of Hh triggers low level signaling, whereas a second pool of Hh is endocytosed and recycled through Hherisomes to stimulate high level signaling and disc pouch growth. Altogether our data indicate that Hherisomes are required to sustain physiological Hh activity necessary for patterning and tissue growth in the wing disc.

Nuclear import of cubitus interruptus is regulated by hedgehog via a mechanism distinct from Ci stabilization and Ci activation

Development ◽  
2000 ◽  
Vol 127 (14) ◽  
pp. 3131-3139 ◽  
Author(s):  
Q.T. Wang ◽  
R.A. Holmgren
Keyword(s):  
Nuclear Import ◽  
Full Length ◽  
Negative Regulators ◽  
Cell Fates ◽  
Cubitus Interruptus ◽  
Drosophila Wing ◽  
Culture Cells ◽  
Tissue Culture Cells ◽  
The Relationship

The Hedgehog (Hh) signal is transduced via Cubitus interruptus (Ci) to specify cell fates in the Drosophila wing. In the absence of Hh, the 155 kDa full-length form of Ci is cleaved into a 75 kDa repressor. Hh inhibits the proteolysis of full-length Ci and facilitates its conversion into an activator. Recently, it has been suggested that Hh promotes Ci nuclear import in tissue culture cells. We have studied the mechanism of Ci nuclear import in vivo and the relationship between nuclear import, stabilization and activation. We found that Ci rapidly translocates to the nucleus in cells close to the anteroposterior (AP) boundary and this rapid nuclear import requires Hh signaling. The nuclear import of Ci is regulated by Hh even under conditions in which Ci is fully stabilized. Furthermore, cells that exhibit Ci stabilization and rapid nuclear import do not necessarily exhibit maximal Ci activity. It has been previously shown that stabilization does not suffice for activation. Consistent with this finding, our results suggest that the mechanisms regulating nuclear import, stabilization and activation are distinct from each other. Finally, we show that cos2 and pka, two molecules that have been characterized primarily as negative regulators of Ci activity, also have positive roles in the activation of Ci in response to Hh.

scholarly journals Molecular Mechanism and Optimal Treatment Strategy in Acute Myeloid Leukemia with Resistance to Drugs and Radiation By NVP-LED225

Blood ◽  
2015 ◽  
Vol 126 (23) ◽  
pp. 3691-3691 ◽  
Author(s):  
Fanyi Meng ◽  
Xiaodong Li ◽  
Bingjie Ding ◽  
Kaikai Huang ◽  
Qiuhua Zhu ◽  
...  
Keyword(s):  
Signaling Pathway ◽  
Myeloid Leukemia ◽  
Hedgehog Signaling ◽  
Leukemia Cells ◽  
Hedgehog Signaling Pathway ◽  
Treatment Groups ◽  
Gli 1 ◽  
Refractory Aml

Abstract PURPOSE: Total body irradiation (TBI) combined with chemotherapy is currently the most effective procedure of traditional preparative myeloablative regimen. However, resistance to chemotherapy in refractory acute myeloid leukemia (AML) is associated with short-time recurrence after Allo-HSCT. To investigate the mechanism of Hedgehog signaling pathway resulting in resistance, we used primary AML cells originated in refractory patients and 3 cell lines including HL60, HL60/ADR (a adriamycin-resistant cells), and HL60/RX (a radiation-resistant cell line established from HL60) as cellular modes to examine the expression of p-IGF-1R, IRS-1, p-Akt, Gli-1, MRP1, Bcl-2, and explored the safety and efficacy of NVP-LDE225 (an inhibitor of Hedgehog pathway) for enhancing the sensitivity to treatment in refractory leukemia in vitro and in vivo. Methods: The expression of Hedgehog signaling pathway was measured in 3 leukemia cell lines, and primary leukemia cells originated in refractory AML patients and non-refractory AML patients using western blot technique. In in vitro experiments, HL60/ADR cells and HL60/RX cells were treated with DMSO (control) or NVP-LDE225 for 48 h, and then assigned in six groups respectively: (a) Control, (b) ADM alone, (c) Radiation alone (d) NVP-LDE225 alone, (e) NVP-LDE225+ADM, (f) NVP-LDE225+Radiation. Flow cytometry, MTT assay and Western-Blot were performed separately to detect apoptosis, adriamycin uptake rate, proliferation inhibit rate and the expression of MRP1, p-IGF-1R, IRS-1, p-Akt, Gli-1, and Bcl-2. Furthermore, based on the results in vitro, the serial tumor volumes, general condition of the mice, complete blood counts, multiple organs injury, and the expression levels of hedgehog signaling pathway were used to detect the antitumor efficacy and toxicity of NVP-LDE225 in HL60/ADR and HL/RX xenograft model. Results: Our result showed that, compared with leukemia cells in non-refractory AML patients and HL60 cells, the expression of hedgehog signaling pathway protein was significantly elevated in refractory AML, HL60/ADR and HL60/RX cells(P<0.01). In addition, we also observed that NVP-LDE225 (10µM) could reverse ADM, DNR, HHT, and Ara-c resistance in HL60/ADR cells. Combining ADM with NVP-LDE225 (20µM) could markedly increase apoptosis and ADM positive rate of intracellular fluorescence detection than other groups (P<0.05). Moreover, combination of NVP-LDE225 with radiation could significantly increase radiation-induced apoptosis and exhibit higher expression of phosphorylation of histone H2AX and BAK than any other single treatment groups both in HL60/RX and HL60/ADR cells(P<0.05). In vivo, both in HL60/RX and HL60/ADR mice model, combination of NVP-LDE225 simultaneously and post 2 days or 5 days with ADM or radiation all presented significantly antitumor effect and high survival rate compared with the control or single agent mice (P<0.01), but there were no significant differences between the three combined treatment groups. Within the combination- and ADM-treated groups, nadir of the white blood cell and platelet counts were reached in day 8 with a gradual recovery starting at day 11. Finally, decrease in IRS-1, Gli-1, p-AKT, and NF-kb expressions were observed after treating with NVP-LDE225 in vitro and in tumor tissue. None of the pathological lesion in the heart, liver, kidney, brain, and lung was observed among all groups. Conclusion: The findings from this study demonstrated that Gli-1/p-Akt/NF-kb pathway play a key role for resistance to both drug and irradiation, and suggested that the combination of hedgehog pathway inhibitor (NVP-LDE225) with chemotherapy or radiotherapy could significantly enhance the antitumor activity via overcoming chemoresistance or radioresistance. The myelosuppression and toxicity could be well tolerated Disclosures No relevant conflicts of interest to declare.

scholarly journals Set7 mediated Gli3 methylation plays a positive role in the activation of Sonic Hedgehog pathway in mammals

eLife ◽  
2016 ◽  
Vol 5 ◽  
Author(s):  
Lin Fu ◽  
Hailong Wu ◽  
Steven Y Cheng ◽  
Daming Gao ◽  
Lei Zhang ◽  
...  
Keyword(s):  
Hedgehog Signaling ◽  
Positive Role ◽  
Shh Signaling ◽  
Cubitus Interruptus ◽  
Tumor Growth And Metastasis ◽  
Double Agent ◽  
The Stability ◽  
Signaling Activation

Hedgehog signaling plays very important roles in development and cancers. Vertebrates have three transcriptional factors, Gli1, Gli2 and Gli3. Among them, Gli3 is a very special transcriptional factor which closely resembles Cubitus interruptus (Ci, in Drosophila) structurally and functionally as a ‘double agent’ for Shh target gene expression. Here we show that Gli3 full-length, but not the truncated form, can be methylated at K436 and K595. This methylation is specifically catalyzed by Set7, a lysine methyltransferase (KMT). Methylation at K436 and K595 respectively increases the stability and DNA binding ability of Gli3, resulting in an enhancement of Shh signaling activation. Furthermore, functional experiments indicate that the Gli3 methylation contributes to the tumor growth and metastasis in non-small cell lung cancer in vitro and in vivo. Therefore, we propose that Set7 mediated methylation is a novel PTM of Gli3, which positively regulates the transactivity of Gli3 and the activation of Shh signaling.

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