scholarly journals Two novel protein O-glucosyltransferases that modify sites distinct from POGLUT1 and affect Notch trafficking and signaling

2018 ◽  
Vol 115 (36) ◽  
pp. E8395-E8402 ◽  
Author(s):  
Hideyuki Takeuchi ◽  
Michael Schneider ◽  
Daniel B. Williamson ◽  
Atsuko Ito ◽  
Megumi Takeuchi ◽  
...  

The Notch-signaling pathway is normally activated by Notch–ligand interactions. A recent structural analysis suggested that a novel O-linked hexose modification on serine 435 of the mammalian NOTCH1 core ligand-binding domain lies at the interface with its ligands. This serine occurs between conserved cysteines 3 and 4 of Epidermal Growth Factor-like (EGF) repeat 11 of NOTCH1, a site distinct from those modified by protein O-glucosyltransferase 1 (POGLUT1), suggesting that a different enzyme is responsible. Here, we identify two novel protein O-glucosyltransferases, POGLUT2 and POGLUT3 (formerly KDELC1 and KDELC2, respectively), which transfer O-glucose (O-Glc) from UDP-Glc to serine 435. Mass spectrometric analysis of NOTCH1 produced in HEK293T cells lacking POGLUT2, POGLUT3, or both genes showed that either POGLUT2 or POGLUT3 can add this novel O-Glc modification. EGF11 of NOTCH2 does not have a serine residue in the same location for this O-glucosylation, but EGF10 of NOTCH3 (homologous to EGF11 in NOTCH1 and -2) is also modified at the same position. Comparison of the sites suggests a consensus sequence for modification. In vitro assays with POGLUT2 and POGLUT3 showed that both enzymes modified only properly folded EGF repeats and displayed distinct acceptor specificities toward NOTCH1 EGF11 and NOTCH3 EGF10. Mutation of the O-Glc modification site on EGF11 (serine 435) in combination with sensitizing O-fucose mutations in EGF8 or EGF12 affected cell-surface presentation of NOTCH1 or reduced activation of NOTCH1 by Delta-like1, respectively. This study identifies a previously undescribed mechanism for fine-tuning the Notch-signaling pathway in mammals.

2020 ◽  
Author(s):  
Jie Yu ◽  
Wenwen Zhang ◽  
Jiayue Huang ◽  
Yating Gou ◽  
Congcong Sun ◽  
...  

Abstract Background: Human amniotic mesenchymal stem cells(hAMSCs) can repair and improve the damaged endometrium which its aplastic disorder is the main reason for intrauterine adhesions(IUAs).Methods: We conducted in vivo and in vitro experiments. In vivo experiments: 45 female Sprague-Dawley(SD) rats were involved and randomized equally into Sham group, IUA group, Estradiol(E2) group, hAMSCs group, and E2 + hAMSCs group. The effect of hAMSCs and E2 only or combined was evaluated by Hematoxylin-eosin(HE) and Masson staining. The expression of epithelial markers and key proteins of Notch signaling pathway by Immunohistochemistry. In vitro experiments: Firstly, the hAMSCs cells were taken and divided into control group and induced group in which hAMSCs were differentiated into endometrial epithelial cells in induced microenvironment, and extracted their RNA respectively. The expression of epithelial markers and Notch1 messenger RNA (mRNA) was detected by Real-time quantitative polymerase chain reaction(qRT-PCR). and the changes in expression position of Notch intracellular domain(NICD) and expression amount of target gene, hairy enhancer of split 1(Hes1) were detected by Immunofluorescence. Then, Activated and inhibited the Notch signaling pathway while induction, and detected mRNA expression of hAMSCs epithelial markers by quantitative real-time polymerase chainreaction (qRT-PCR) respectively and detected hAMSCs cell cycle by flow cytometric. Results:This study showed that hAMSCs alone or combined with E2 could promote endometrial repair, and Notch signaling pathway a great role in it. And otherwise, the activation or habitation of Notch signaling pathway determines whether hAMSCs could differentiate into endometrial epithelial cells or not.Conclusion: we concluded that activate the Notch signaling pathway promote the differentiation of hAMSCs into endometrial epithelial cells, and further treat IUAs.


2020 ◽  
Vol 2020 ◽  
pp. 1-16
Author(s):  
Xing Li ◽  
Dan Luo ◽  
Yu Hou ◽  
Yonghui Hou ◽  
Shudong Chen ◽  
...  

Spinal cord microcirculation involves functioning endothelial cells at the blood spinal cord barrier (BSCB) and maintains normal functioning of spinal cord neurons, axons, and glial cells. Protection of both the function and integrity of endothelial cells as well as the prevention of BSCB disruption may be a strong strategy for the treatment of spinal cord injury (SCI) cases. Sodium Tanshinone IIA silate (STS) is used for the treatment of coronary heart disease and improves microcirculation. Whether STS exhibits protective effects for SCI microcirculation is not yet clear. The purpose of this study is to investigate the protective effects of STS on oxygen-glucose deprivation- (OGD-) induced injury of spinal cord endothelial cells (SCMECs) in vitro and to explore effects on BSCB and neurovascular protection in vivo. SCMECs were treated with various concentrations of STS (1 μM, 3 μM, and 10 μM) for 24 h with or without OGD-induction. Cell viability, tube formation, migration, and expression of Notch signaling pathway components were evaluated. Histopathological evaluation (H&E), Nissl staining, BSCB permeability, and the expression levels of von Willebrand Factor (vWF), CD31, NeuN, and Notch signaling pathway components were analyzed. STS was found to improve SCMEC functions and reduce inflammatory mediators after OGD. STS also relieved histopathological damage, increased zonula occludens-1 (ZO-1), inhibited BSCB permeability, rescued microvessels, protected motor neuromas, and improved functional recovery in a SCI model. Moreover, we uncovered that the Notch signaling pathway plays an important role during these processes. These results indicated that STS protects microcirculation in SCI, which may be used as a therapeutic strategy for SCI in the future.


Cancers ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 1439
Author(s):  
Hyeon-Gu Kang ◽  
Won-Jin Kim ◽  
Myung-Giun Noh ◽  
Kyung-Hee Chun ◽  
Seok-Jun Kim

Spondin-2 (SPON2) is involved in cancer progression and metastasis of many tumors; however, its role and underlying mechanism in gastric cancer are still obscure. In this study, we investigated the role of SPON2 and related signaling pathway in gastric cancer progression and metastasis. SPON2 expression levels were found to be upregulated in gastric cancer cell lines and patient tissues compared to normal gastric epithelial cells and normal controls. Furthermore, SPON2 silencing was observed to decrease cell proliferation and motility and reduce tumor growth in xenograft mice. Conversely, SPON2 overexpression was found to increase cell proliferation and motility. Subsequently, we focused on regulatory mechanism of SPON2 in gastric cancer. cDNA microarray and in vitro study showed that Notch signaling is significantly correlated to SPON2 expression. Therefore, we confirmed how Notch signaling pathway regulate SPON2 expression using Notch signaling-related transcription factor interaction and reporter gene assay. Additionally, activation of Notch signaling was observed to increase cell proliferation, migration, and invasion through SPON2 expression. Our study demonstrated that Notch signaling-mediated SPON2 upregulation is associated with aggressive progression of gastric cancer. In conclusion, we suggest upregulated SPON2 via Notch signaling as a potential target gene to inhibit gastric cancer progression.


Cells ◽  
2020 ◽  
Vol 9 (8) ◽  
pp. 1879 ◽  
Author(s):  
Christian T. Meisel ◽  
Cristina Porcheri ◽  
Thimios A. Mitsiadis

The Notch signaling pathway regulates cell proliferation, cytodifferentiation and cell fate decisions in both embryonic and adult life. Several aspects of stem cell maintenance are dependent from the functionality and fine tuning of the Notch pathway. In cancer, Notch is specifically involved in preserving self-renewal and amplification of cancer stem cells, supporting the formation, spread and recurrence of the tumor. As the function of Notch signaling is context dependent, we here provide an overview of its activity in a variety of tumors, focusing mostly on its role in the maintenance of the undifferentiated subset of cancer cells. Finally, we analyze the potential of molecules of the Notch pathway as diagnostic and therapeutic tools against the various cancers.


Cell Cycle ◽  
2012 ◽  
Vol 11 (2) ◽  
pp. 264-276 ◽  
Author(s):  
Tilman Borggrefe ◽  
Robert Liefke

2019 ◽  
Vol 10 (17) ◽  
pp. 4114-4122 ◽  
Author(s):  
Guifang He ◽  
Tianlong Mu ◽  
Yali Yuan ◽  
Wenyan Yang ◽  
Yuan Zhang ◽  
...  

2018 ◽  
Vol 2018 ◽  
pp. 1-11
Author(s):  
Yun-Cang Wang ◽  
Zhi-Qiang Wang ◽  
Yong Yuan ◽  
Tao Ren ◽  
Peng-Zhi Ni ◽  
...  

Objective. To explore the role of Notch signaling in the development of Barrett’s esophagus. Methods. Patients with esophagectomy and gastric interposition were recruited as a human model of gastroesophageal reflux disease. The expressions of Notch signaling genes in normal esophagus from surgical specimen and columnar metaplasia in the esophageal remnant after esophagectomy were evaluated by real time quantitative Polymerase Chain Reaction (RT-qPCR) and immunohistochemistry (IHC). For in vitro experiments, Het-1A cells were treated with hydrochloric acid, deoxycholic acid, mixture of hydrochloric acid and deoxycholic acid, or Notch1-siRNA, and expressions of Notch1, Hes1, MUC2, and K13 were evaluated via RT-qPCR and western blot. Results. Samples were obtained from 36 patients with columnar metaplasia in the esophageal remnant. Both IHC and RT-qPCR indicated that Notch1 and Hes1 expressions were significantly higher in normal esophagus than that in metaplasia. Hydrochloric acid and deoxycholic acid suppressed Notch1, Hes1, and K13 expressions, in concert with increasing MUC2 expressions. Notch inhibition by Notch1-siRNA contributed to the downregulation of Notch1, Hes1, and K13 expressions, whereas MUC2 expression was enhanced. Conclusions. Both hydrochloric acid and deoxycholic acid could suppress Notch signaling pathway in esophageal epithelial cells, and inhibited Notch signaling has important functions in the development of Barrett’s esophagus.


2021 ◽  
Author(s):  
Xin Ye ◽  
Mengyi Li ◽  
Wei Bian ◽  
Junwei Li ◽  
Ting Zhang ◽  
...  

Abstract Although the ependymal cells were reported to have the characteristics of neural stem cells (NSCs), the properties of CD133-ependymal cells have not been uncovered, in particular, it is largely unknown about the effect of Notch signaling pathway on the neurogenesis of CD133-positive ependymal cells. By using the transgenic mouse and primarily cultured ependymal cells, we found that the immunoreactivity for prominin-1/CD133 was exclusively localized in the subventricular zone (SVZ) and ependymal layer of ventricles, moreover, most CD133-positive ependymal cells were co-labeled with Nestin. In addition, RBP-J, a key nuclear effector of Notch signaling pathway, was highly active in CD133-positive ependymal cells. Our results demonstrated that CD133-positive ependymal cells can differentiate into the immature and mature neurons, in particular, the number of CD133-positive ependymal cells differentiating into the immature and mature neurons was significantly increased following the deficiency or interference of RBP-J in vivo or in vitro. By using real-time qPCR and Western blot, we found that RBP-J and Hes1 were down-regulated while Notch1 was up-regulated in the expression levels of mRNAs and proteins following the deficiency or interference of RBP-J in vivo or in vitro. These results demonstrated RBP-J deficiency promoted the proliferation and differentiation of CD133-positive ependymal cells. Therefore, we speculated that RBP-J could maintain CD133-positive ependymal cells in the characteristics of NSCs possibly by regulating Notch1/RBP-J/Hes1 pathway.


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