scholarly journals Multifaceted regulation of Notch signaling by glycosylation

Glycobiology ◽  
2020 ◽  
Author(s):  
Ashutosh Pandey ◽  
Nima Niknejad ◽  
Hamed Jafar-Nejad

Abstract To build a complex body composed of various cell types and tissues and to maintain tissue homeostasis in the postembryonic period, animals use a small number of highly conserved intercellular communication pathways. Among these is the Notch signaling pathway, which is mediated via the interaction of transmembrane Notch receptors and ligands usually expressed by neighboring cells. Maintaining optimal Notch pathway activity is essential for normal development, as evidenced by various human diseases caused by decreased and increased Notch signaling. It is therefore not surprising that multiple mechanisms are used to control the activation of this pathway in time and space. Over the last 20 years, protein glycosylation has been recognized as a major regulatory mechanism for Notch signaling. In this review, we will provide a summary of the various types of glycan that have been shown to modulate Notch signaling. Building on recent advances in the biochemistry, structural biology, cell biology and genetics of Notch receptors and the glycosyltransferases that modify them, we will provide a detailed discussion on how various steps during Notch activation are regulated by glycans. Our hope is that the current review article will stimulate additional research in the field of Notch glycobiology and will potentially be of benefit to investigators examining the contribution of glycosylation to other developmental processes.

2018 ◽  
Author(s):  
Nagarajan Nandagopal ◽  
Leah A. Santat ◽  
Michael B. Elowitz

AbstractThe Notch signaling pathway consists of transmembrane ligands and receptors that can interact both within the same cell (cis) and across cell boundaries (trans). Previous work has shown that cis-interactions act to inhibit productive signaling. Here, by analyzing Notch activation in single cells while controlling cell density and ligand expression level, we show that cis-ligands can in fact activate Notch receptors. This cis-activation process resembles trans-activation in its ligand level dependence, susceptibility to cis-inhibition, and sensitivity to Fringe modification. Cis-activation occurred for multiple ligand-receptor pairs, in diverse cell types, and affected survival and differentiation in neural stem cells. Finally, mathematical modeling shows how cis-activation could potentially expand the capabilities of Notch signaling, for example enabling “negative” signaling. These results establish cis-activation as a prevalent mode of signaling in the Notch pathway, and should contribute to a more complete understanding of how Notch signaling functions in developmental, physiological, and biomedical contexts.


2019 ◽  
Vol 2019 ◽  
pp. 1-15 ◽  
Author(s):  
M. V. Giuli ◽  
E. Giuliani ◽  
I. Screpanti ◽  
D. Bellavia ◽  
S. Checquolo

Triple-negative breast cancer (TNBC) is a subgroup of 15%-20% of diagnosed breast cancer patients. It is generally considered to be the most difficult breast cancer subtype to deal with, due to the lack of estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2), which usually direct targeted therapies. In this scenario, the current treatments of TNBC-affected patients rely on tumor excision and conventional chemotherapy. As a result, the prognosis is overall poor. Thus, the identification and characterization of targets for novel therapies are urgently required. The Notch signaling pathway has emerged to act in the pathogenesis and tumor progression of TNBCs. Firstly, Notch receptors are associated with the regulation of tumor-initiating cells (TICs) behavior, as well as with the aetiology of TNBCs. Secondly, there is a strong evidence that Notch pathway is a relevant player in mammary cancer stem cells maintenance and expansion. Finally, Notch receptors expression and activation strongly correlate with the aggressive clinicopathological and biological phenotypes of breast cancer (e.g., invasiveness and chemoresistance), which are relevant characteristics of TNBC subtype. The purpose of this up-to-date review is to provide a detailed overview of the specific role of all four Notch receptors (Notch1, Notch2, Notch3, and Notch4) in TNBCs, thus identifying the Notch signaling pathway deregulation/activation as a pathognomonic feature of this breast cancer subtype. Furthermore, this review will also discuss recent information associated with different therapeutic options related to the four Notch receptors, which may be useful to evaluate prognostic or predictive indicators as well as to develop new therapies aimed at improving the clinical outcome of TNBC patients.


Development ◽  
2001 ◽  
Vol 128 (18) ◽  
pp. 3533-3542
Author(s):  
Gerri R. Buckles ◽  
Cordelia Rauskolb ◽  
John Lee Villano ◽  
Flora N. Katz

The molecular basis of segmentation and regional growth during morphogenesis of Drosophila legs is poorly understood. We show that four-jointed is not only required for these processes, but also can direct ectopic growth and joint initiation when its normal pattern of expression is disturbed. These effects are non-autonomous, consistent with our demonstration of both transmembrane and secreted forms of the protein in vivo. The similarities between four-jointed and Notch phenotypes led us to further investigate the relationships between these pathways. Surprisingly, we find that although four-jointed expression is regulated downstream of Notch activation, four-jointed can induce expression of the Notch ligands, Serrate and Delta, and may thereby participate in a feedback loop with the Notch signaling pathway. We also show that four-jointed interacts with abelson, enabled and dachs, which leads us to suggest that one target of four-jointed signaling is the actin cytoskeleton. Thus, four-jointed may bridge the gap between the signals that direct morphogenesis and those that carry it out.


2021 ◽  
Vol 6 (1) ◽  
Author(s):  
Yang Pu ◽  
Ya Song ◽  
Mengdi Zhang ◽  
Caifeng Long ◽  
Jie Li ◽  
...  

AbstractIntestinal epithelium serves as the first barrier against the infections and injuries that mediate colonic inflammation. Colorectal cancer is often accompanied with chronic inflammation. Differed from its well-known oncogenic role in many malignancies, we present here that Golgi membrane protein 1 (GOLM1, also referred to as GP73) suppresses colorectal tumorigenesis via maintenance of intestinal epithelial barrier. GOLM1 deficiency in mice conferred susceptibility to mucosal inflammation and colitis-induced epithelial damage, which consequently promoted colon cancer. Mechanistically, depletion of GOLM1 in intestinal epithelial cells (IECs) led to aberrant Notch activation that interfered with IEC differentiation, maturation, and lineage commitment in mice. Pharmacological inhibition of Notch pathway alleviated epithelial lesions and restrained pro-tumorigenic inflammation in GOLM1-deficient mice. Therefore, GOLM1 maintains IEC homeostasis and protects against colitis and colon tumorigenesis by modulating the equilibrium of Notch signaling pathway.


2018 ◽  
Vol 2018 ◽  
pp. 1-11 ◽  
Author(s):  
Emmanuel N. Kontomanolis ◽  
Sofia Kalagasidou ◽  
Stamatia Pouliliou ◽  
Xanthoula Anthoulaki ◽  
Nikolaos Georgiou ◽  
...  

Objective. Notch signaling pathway is a vital parameter of the mammalian vascular system. In this review, the authors summarize the current knowledge about the impact of the Notch signaling pathway in breast cancer progression and the therapeutic role of Notch’s inhibition.Methods. The available literature in MEDLINE, PubMed, and Scopus, regarding the role of the Notch pathway in breast cancer progression was searched for related articles from about 1973 to 2017 including terms such as “Notch,” “Breast Cancer,” and “Angiogenesis.”Results. Notch signaling controls the differentiation of breast epithelial cells during normal development. Studies confirm that the Notch pathway has a major participation in breast cancer progression through overexpression and/or abnormal genetic type expression of the notch receptors and ligands that determine angiogenesis. The cross-talk of Notch and estrogens, the effect of Notch in breast cancer stem cells formation, and the dependable Notch overexpression during breast tumorigenesis have been studied enough and undoubtedly linked to breast cancer development. The already applied therapeutic inhibition of Notch for breast cancer can drastically change the course of the disease.Conclusion. Current data prove that Notch pathway has a major participation and multiple roles during breast tumor progression. Inhibition of Notch receptors and ligands provides innovative therapeutic results and could become the therapy of choice in the next few years, even though further research is needed to reach safe conclusions.


eLife ◽  
2019 ◽  
Vol 8 ◽  
Author(s):  
Nagarajan Nandagopal ◽  
Leah A Santat ◽  
Michael B Elowitz

The Notch signaling pathway consists of transmembrane ligands and receptors that can interact both within the same cell (cis) and across cell boundaries (trans). Previous work has shown that cis-interactions act to inhibit productive signaling. Here, by analyzing Notch activation in single cells while controlling cell density and ligand expression level, we show that cis-ligands can also activate Notch receptors. This cis-activation process resembles trans-activation in its ligand level dependence, susceptibility to cis-inhibition, and sensitivity to Fringe modification. Cis-activation occurred for multiple ligand-receptor pairs, in diverse cell types, and affected survival in neural stem cells. Finally, mathematical modeling shows how cis-activation could potentially expand the capabilities of Notch signaling, for example enabling ‘negative’ (repressive) signaling. These results establish cis-activation as an additional mode of signaling in the Notch pathway, and should contribute to a more complete understanding of how Notch signaling functions in developmental, physiological, and biomedical contexts.


Blood ◽  
2012 ◽  
Vol 120 (21) ◽  
pp. 1840-1840
Author(s):  
Dehui Xu ◽  
Jingsong Hu ◽  
Elke De Bruyne ◽  
Eline Menu ◽  
Rik Schots ◽  
...  

Abstract Abstract 1840 One of the greatest challenges in multiple myeloma (MM) treatment is to overcome drug resistance. More and more evidence showed that not only the MM tumor cells should be targeted but also the bone marrow (BM) micro-environment. Interactions of MM cells with the BM micro-environment have a pivotal role in MM cell proliferation, survival, migration, angiogenesis as well as drug resistance. Many pathways are involved including the conserved Notch signaling pathway. The interaction of Notch receptors and ligands between adjacent cells induces proteolytic cleavage and release of the intracellular domain of the Notch receptor, also called Notch intracellular domains (NICD). NICD will then enter the nucleus and modify the expression of downstream target genes. Notch receptors are expressed by MM cells and Notch ligand Dll1 is present on bone marrow (BM) stromal cells. We investigated whether Notch activation in myeloma cells by the interaction with Dll1 on stromal cells contributes to bortezomib resistance. We analyzed Notch1 and Notch2 surface expression by flow cytometry on MM cells after Dll1 interaction using a stromal cell line modified to overexpress Dll1. Notch1 surface expression was not disturbed on mouse 5T33MMvt and human MMS1 and LP-1 cells while Notch2 expression on MM cells was significantly decreased after Dll1 interaction for 2 days. Next, we investigated NICD1 and NICD2 expression by western blot after Dll1/Notch interaction. NICD1 did not change in murine 5T33MMvt and human LP-1 and MMS-1 cells, while NICD2 is increased after Dll1 interaction. These results suggest that Dll1 can activate Notch signaling likely through the Notch2 receptor. We investigated whether Dll1/Notch activation could contribute to MM bortezomib resistance. MM cells were cocultured on immobilized recombinant Dll1 ligand and treated with 5 nM bortezomib for 48h. Compared to control, MM cells cocultured with Dll1 ligand were less sensitive to bortezomib. Furthermore, blocking the Notch pathway by DAPT (a gamma secretase inhibitor, GSI) could reverse this effect and increased the sensitivity to bortezomib. To delineate the molecular mechanism of Dll1-induced bortezomib resistance, we performed a drug resistance and metabolism gene array and found that CYP1A1 was significantly upregulated by Dll1/Notch interaction. CYP1A1 is a member of the cytochrome P450 family and regulates drug metabolism. We further demonstrated that inhibiting CYP1A1 by either α-Naphthoflavone (inhibitor) or CYP1A1-siRNA increases the sensitivity of MM cells to bortezomib, suggesting that CYP1A1 is involved in bortezomib resistance. As also previously demonstrated, CD138- 5T33MM cells are less sensitive to bortezomib than CD138+ 5T33MM cells. We analyzed CYP1A1 expression and activity and observed a higher CYP1A1 amount in CD138- cells compared to CD138+ MM cells. The higher CYP1A1 expression in CD138- cells might be a possible mechanism for their decreased bortezomib sensitivity compared to CD138+ cells. In addition, an in vivo experiment was performed. Combination treatment of DAPT with bortezomib was able to increase bortezomib sensitivity and prolonged overall survival in the 5T33MM mouse model. In conclusion, our results suggest that Dll1/Notch activation contributes to bortezomib resistance by upregulating CYP1A1, a molecule involved in drug metabolism. Our data provide a potential strategy to overcome bortezomib resistance by combination with a Notch pathway inhibitor. Disclosures: No relevant conflicts of interest to declare.


2020 ◽  
Vol 2020 ◽  
pp. 1-8
Author(s):  
Jilani Purusottapatnam Shaik ◽  
Ibrahim O. Alanazi ◽  
Akbar Ali Khan Pathan ◽  
Narasimha Reddy Parine ◽  
Majid A. Almadi ◽  
...  

Colorectal cancer is a major health concern as it ranks third in incidence and second major cause of cancer-related deaths worldwide. A leading cause of treatment failure has been attributed to cancer stem cells that can invariably resist existing chemotherapeutic regimens. Notch signaling pathway has been involved in the maintenance of stem cells besides being crucial in cell fate decision and embryonic development. This pathway has also been implicated in several human malignancies including colorectal cancer. We investigated mRNA expression of four Notch receptors (Notch1–4), five ligands (Jag1, Jag2, Dll1, Dll3, and Dll4), and four target genes (Hes1, Hes5, Hey1, and Hey2) using highly specific TaqMan gene expression assays in colorectal adenomas and cancers. Upregulated expression of Notch receptors ranged between 29 and 73% in colorectal cancers and between 11 and 56% in adenomas. Expression of Notch3 and Notch4 receptors was significantly higher in colorectal cancers compared to normal and adenoma tissues. The Jagged and Delta-like ligands were overexpressed between 25 and 52% in colorectal cancers, while in adenomas, it ranged between 0 and 33%. Combining the data for upregulation of receptors and ligands suggests that 86% colorectal cancers and 56% adenomas exhibited overexpression of Notch pathway genes in our cohort. Notch target genes were upregulated between 24 and 33% in colorectal cancers and between 11 and 22% in adenomas. Collating upregulation of Notch receptors and ligands with the target genes showed concordance in 58% colorectal tumors. Additionally, we evaluated expression of Notch receptors, ligands, and target genes with prognosis using the TCGA mRNA expression dataset. Patients overexpressing Notch3, Notch4, and Hey1 had significantly poorer overall survival relative to those having lower levels of these genes. Taken together, Notch signaling components are aberrantly overexpressed in colorectal tumors, and development of therapeutics targeting the Notch pathway may prove to be beneficial in the management of colorectal cancers.


Biomolecules ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 309
Author(s):  
Wataru Saiki ◽  
Chenyu Ma ◽  
Tetsuya Okajima ◽  
Hideyuki Takeuchi

The 100th anniversary of Notch discovery in Drosophila has recently passed. The Notch is evolutionarily conserved from Drosophila to humans. The discovery of human-specific Notch genes has led to a better understanding of Notch signaling in development and diseases and will continue to stimulate further research in the future. Notch receptors are responsible for cell-to-cell signaling. They are activated by cell-surface ligands located on adjacent cells. Notch activation plays an important role in determining the fate of cells, and dysregulation of Notch signaling results in numerous human diseases. Notch receptors are primarily activated by ligand binding. Many studies in various fields including genetics, developmental biology, biochemistry, and structural biology conducted over the past two decades have revealed that the activation of the Notch receptor is regulated by unique glycan modifications. Such modifications include O-fucose, O-glucose, and O-N-acetylglucosamine (GlcNAc) on epidermal growth factor-like (EGF) repeats located consecutively in the extracellular domain of Notch receptors. Being fine-tuned by glycans is an important property of Notch receptors. In this review article, we summarize the latest findings on the regulation of Notch activation by glycosylation and discuss future challenges.


2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Masaharu Yoshihara ◽  
Teppei Nishino ◽  
Manoj Kumar Yadav ◽  
Akihiro Kuno ◽  
Takeshi Nagata ◽  
...  

Abstract Objective The Delta-Notch signaling pathway induces fine-grained patterns of differentiation from initially homogeneous progenitor cells in many biological contexts, including Drosophila bristle formation, where mathematical modeling reportedly suggests the importance of production rate of the components of this signaling pathway. In contrast, the epithelial differentiation of bile ducts in the developing liver is unique in that it occurs around the portal vein cells, which express extremely high amounts of Delta ligands and act as a disturbance for the amount of Delta ligands in the field by affecting the expression levels of downstream target genes in the cells nearby. In the present study, we mathematically examined the dynamics of the Delta-Notch signaling pathway components in disturbance-driven biliary differentiation, using the model for fine-grained patterns of differentiation. Results A portal vein cell induced a high Notch signal in its neighboring cells, which corresponded to epithelial differentiation, depending on the production rates of Delta ligands and Notch receptors. In addition, this epithelial differentiation tended to occur in conditions where fine-grained patterning was reported to be lacking. These results highlighted the potential importance of the stability towards homogeneity determined by the production rates in Delta ligands and Notch receptors, in a disturbance-dependent epithelial differentiation.


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