Regulation of primordial follicle recruitment by cross-talk between the Notch and phosphatase and tensin homologue (PTEN)/AKT pathways

2016 ◽  
Vol 28 (6) ◽  
pp. 700 ◽  
Author(s):  
Lin-Qing Wang ◽  
Jing-Cai Liu ◽  
Chun-Lei Chen ◽  
Shun-Feng Cheng ◽  
Xiao-Feng Sun ◽  
...  
Keyword(s):  
Granulosa Cells ◽  
Butyl Ester ◽  
Primordial Follicle ◽  
Notch Signalling ◽  
Signalling Pathway ◽  
Negative Regulator ◽  
Signalling Pathways ◽  
Notch Signalling Pathway ◽  
Primordial Follicles ◽  
Phosphatase And Tensin Homologue

The growth of oocytes and the development of follicles require certain pathways involved in cell proliferation and survival, such as the phosphatidylinositol 3-kinase (PI3K) pathway and the Notch signalling pathway. The aim of the present study was to investigate the interaction between Notch and the PI3K/AKT signalling pathways and their effects on primordial follicle recruitment. When the Notch pathway was inhibited by L-685,458 or N-[N-(3,5-difluorophenacetyl)-l-alanyl]-S-phenylglycinet-butyl ester (DAPT) in vitro, the expression of genes in the pathway and the percentage of oocytes in growing follicles decreased significantly in mouse ovaries. By 2 days postpartum, ovaries exposed to DAPT, short interference (si) RNA against Notch1 or siRNA against Hairy and enhancer of split-1 (Hes1) had significantly decreased expression of HES1, the target protein of the Notch signalling pathway. In contrast, expression of phosphatase and tensin homologue (Pten), a negative regulator of the AKT signalling pathway, was increased significantly. Co immunoprecipitation (Co-IP) revealed an interaction between HES1 and PTEN. In addition, inhibition of the Notch signalling pathway suppressed AKT phosphorylation and the proliferation of granulosa cells. In conclusion, the recruitment of primordial follicles was affected by the proliferation of granulosa cells and regulation of the interaction between the Notch and PI3K/AKT signalling pathways.

scholarly journals HDAC6 regulates primordial follicle activation through mTOR signaling pathway

2021 ◽  
Vol 12 (6) ◽  
Author(s):  
Tuo Zhang ◽  
Meina He ◽  
Lihua Zhao ◽  
Shaogang Qin ◽  
Zijian Zhu ◽  
...  
Keyword(s):  
Granulosa Cells ◽  
Primordial Follicle ◽  
Mtor Signaling ◽  
Negative Regulator ◽  
Expression Level ◽  
Female Reproduction ◽  
Primordial Follicles ◽  
Primordial Follicle Activation ◽  
Follicle Activation

AbstractPrimordial follicle pool established perinatally is a non-renewable resource which determines the female fecundity in mammals. While the majority of primordial follicles in the primordial follicle pool maintain dormant state, only a few of them are activated into growing follicles in adults in each cycle. Excessive activation of the primordial follicles accelerates follicle pool consumption and leads to premature ovarian failure. Although previous studies including ours have emphasized the importance of keeping the balance between primordial follicle activation and dormancy via molecules within the primordial follicles, such as TGF-β, E-Cadherin, mTOR, and AKT through different mechanisms, the homeostasis regulatory mechanisms of primordial follicle activation remain unclear. Here, we reported that HDAC6 acts as a key negative regulator of mTOR in dormant primordial follicles. In the cytoplasm of both oocytes and granulosa cells of primordial follicles, HDAC6 expressed strong, however in those activated primordial follicles, its expression level is relatively weaker. Inhibition or knockdown of HDAC6 significantly promoted the activation of limited primordial follicles while the size of follicle pool was not affected profoundly in vitro. Importantly, the expression level of mTOR in the follicle and the activity of PI3K in the oocyte of the follicle were simultaneously up-regulated after inhibiting of HDAC6. The up-regulated mTOR leads to not only the growth and differentiation of primordial follicles granulosa cells (pfGCs) into granulosa cells (GCs), but the increased secretion of KITL in these somatic cells. As a result, inhibition of HDAC6 awaked the dormant primordial follicles of mice in vitro. In conclusion, HDAC6 may play an indispensable role in balancing the maintenance and activation of primordial follicles through mTOR signaling in mice. These findings shed new lights on uncovering the epigenetic factors involved physiology of sustaining female reproduction.

scholarly journals The role of Notch ligand, Delta-like ligand 4 (DLL4), in cancer angiogenesis—implications for therapy

2021 ◽  
Author(s):  
Marlena Brzozowa-Zasada
Keyword(s):  
Cancer Therapy ◽  
Notch Signalling ◽  
Signalling Pathway ◽  
Gamma Secretase ◽  
Tumour Angiogenesis ◽  
Notch Signalling Pathway ◽  
Expression Levels ◽  
Blocking Agents ◽  
Anti Cancer

Summary Background It is generally accepted that angiogenesis is a complex and tightly regulated process characterized by the growth of blood vessels from existing vasculature. Activation of the Notch signalling pathway affects multiple aspects of vascular development. One of the components of the Notch signalling pathway, Delta-like ligand 4 (DLL4), has recently appeared as a critical regulator of tumour angiogenesis and thus as a promising therapeutic target. Methods This review article includes available data from peer-reviewed publications associated with the role of DLL4 in cancer angiogenesis. Searches were performed in PubMed, EMBASE, Google Scholar and Web of Science using the terms “tumour angiogenesis”, “DLL4”, “Notch signalling” and “anti-cancer therapy”. Results The survival curves of cancer patients revealed that the patients with high DLL4 expression levels had significantly shorter survival times than the patients with low DLL4 expression. Moreover, a positive correlation was also identified between DLL4 and VEGF receptorsʼ expression levels. It seems that inhibition of DLL4 may exert potent growth inhibitory effects on some tumours resistant to anti-VEGF therapies. A great number of blocking agents of DLL4/Notch signalling including anti-DLL4 antibodies, DNA vaccination, Notch antibodies and gamma-secretase inhibitors have been studied in preclinical tumour models. Conclusion DLL4 seems to be a promising target in anti-cancer therapy. Nevertheless, the careful evaluation of adverse effects on normal physiological processes in relation to therapeutic doses of anti-DLL4 drugs will be significant for advancement of DLL4 blocking agents in clinical oncology.

scholarly journals Novel players in the Notch signalling pathway

2007 ◽  
Vol 306 (1) ◽  
pp. 301
Author(s):  
Hugo J. Bellen ◽  
Melih Acar ◽  
Hamed Jafar Nejad ◽  
Anchi Tien ◽  
Akhila Rajan
Keyword(s):  
Notch Signalling ◽  
Signalling Pathway ◽  
Notch Signalling Pathway

Conservation of the Notch signalling pathway in mammalian neurogenesis

Development ◽  
1997 ◽  
Vol 124 (6) ◽  
pp. 1139-1148 ◽  
Author(s):  
J.L. Pompa de la ◽  
A. Wakeham ◽  
K.M. Correia ◽  
E. Samper ◽  
S. Brown ◽  
...  
Keyword(s):  
Cell Fate ◽  
Notch Pathway ◽  
Stem Cell Differentiation ◽  
Notch Signalling ◽  
Signalling Pathway ◽  
Notch Signalling Pathway ◽  
Altered Expression ◽  
Cell Fate Decisions ◽  
Targeted Mutation ◽  
Multiple Cell

The Notch pathway functions in multiple cell fate determination processes in invertebrate embryos, including the decision between the neuroblast and epidermoblast lineages in Drosophila. In the mouse, targeted mutation of the Notch pathway genes Notch1 and RBP-Jk has demonstrated a role for these genes in somite segmentation, but a function in neurogenesis and in cell fate decisions has not been shown. Here we show that these mutations lead to altered expression of the Notch signalling pathway homologues Hes-5, Mash-1 and Dll1, resulting in enhanced neurogenesis. Precocious neuronal differentiation is indicated by the expanded expression domains of Math4A, neuroD and NSCL-1. The RBP-Jk mutation has stronger effects on expression of these genes than does the Notch1 mutation, consistent with functional redundancy of Notch genes in neurogenesis. Our results demonstrate conservation of the Notch pathway and its regulatory mechanisms from fly to mouse, and support a role for the murine Notch signalling pathway in the regulation of neural stem cell differentiation.

Overexpressing microRNA-34a overcomes ABCG2-mediated drug resistance to 5-FU in side population cells from colon cancer via suppressing DLL1

2020 ◽  
Vol 167 (6) ◽  
pp. 557-564
Author(s):  
Zheng-Yuan Xie ◽  
Fen-Fen Wang ◽  
Zhi-Hua Xiao ◽  
Si-Fu Liu ◽  
Sheng-Lan Tang ◽  
...  
Keyword(s):  
Colon Cancer ◽  
Drug Resistance ◽  
Side Population ◽  
Critical Role ◽  
Notch Pathway ◽  
Notch Signalling ◽  
Signalling Pathway ◽  
Luciferase Reporter ◽  
Small Subset ◽  
Notch Signalling Pathway

Abstract Colon cancer side population (SP) cells are a small subset of cancer cells that have cancer stemness capacity and enhanced drug resistance. ABCG2 is a multidrug resistance-related protein in SP cells and has been demonstrated to be regulated by Notch signalling pathway. Recently, microRNAs are reported to play a critical role in SP cell fate. However, their role in ABCG2-mediated drug resistance in colon cancer SP cells remains unclear. In the current study, the different expressions of miR-552, miR-611, miR-34a and miR-5000-3p were compared within SP and non-SP cells, which were separated from human colon cancer cell lines (SW480 and LoVo). We found that miR-34a was significantly down-regulated in SP cells and that overexpressing miR-34a overcame drug resistance to 5-fluorouracil (5-FU). The luciferase reporter assay indicated that miR-34a negatively regulated DLL1, a ligand of Notch signalling pathway, via binding with 3′-untranslated region of its messenger RNA. In addition, overexpressing miR-34a overcame ABCG2-mediated resistance to 5-FU via DLL1/Notch pathway in vitro, and suppressed tumour growth under 5-FU treatment in vivo. In conclusion, our findings suggest that miR-34a acts as a tumour suppressor via enhancing chemosensitivity to 5-FU in SP cells, which provides a novel therapeutic target in chemotherapy-resistant colon cancer.

scholarly journals Origin and evolution of the Notch signalling pathway: an overview from eukaryotic genomes

2009 ◽  
Vol 9 (1) ◽  
pp. 249 ◽  
Author(s):  
Eve Gazave ◽  
Pascal Lapébie ◽  
Gemma S Richards ◽  
Frédéric Brunet ◽  
Alexander V Ereskovsky ◽  
...  
Keyword(s):  
Notch Signalling ◽  
Signalling Pathway ◽  
Notch Signalling Pathway ◽  
Origin And Evolution ◽  
Eukaryotic Genomes
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