SEARCH · PubMed Health

Results for “Receptor, Notch2”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 163 records · Page 9Linked to original sources

PubMed2002

Specific down-modulation of Notch1 signaling in cervical cancer cells is required for sustained HPV-E6/E7 expression and late steps of malignant transformation.

The Notch family of cell surface receptors plays a key role in cell-fate determination and differentiation, functioning in a cell- and context-specific manner. In mammalian cells, Notch activation is generally thought to maintain stem cell potential and inhibit differentiation, thereby promoting carcinogenesis. However, in other contexts such as primary epithelial cells (keratinocytes), increased Notch activity causes exit from the cell cycle and/or commitment to differentiation. We now report that expression of the endogenous Notch1 gene is markedly reduced in a panel of cervical carcinoma cells whereas expression of Notch2 remains elevated, and Notch1 expression is similarly reduced or absent in invasive cervical cancers. Conversely, expression of activated Notch1 causes strong growth inhibition of HPV-positive, but not HPV-negative, cervical carcinoma cells, but exerts no such effects on other epithelial tumor cells. Increased Notch1 signaling, but not Notch2, causes a dramatic down-modulation of HPV-driven transcription of the E6/E7 viral genes, through suppression of AP-1 activity by up-regulation of the Fra-1 family member and decreased c-Fos expression. Thus, Notch1 exerts specific protective effects against HPV-induced transformation through suppression of E6/E7 expression, and down-modulation of Notch1 expression is likely to play an important role in late stages of HPV-induced carcinogenesis.

Cell Transformation, Neoplastic↗

PubMed2005

Activation of the Notch signaling pathway in response to pulp capping of rat molars.

Notch signaling is an evolutionarily conserved pathway that controls the developmental choices made by individual cells. Cells communicate via Notch receptors and their ligands, which direct decisions on the fate of stem cells according to the states of their neighbors. In this study we explored Notch signaling after the pulp capping of adult first upper rat molars. The wound was capped with calcium hydroxide. In situ hybridization revealed an increased expression of Notch signaling genes on day 1, which showed a tendency to decrease on day 3. Notch1 increased in the subodontoblast zone and close to the lesion limited to a few cells. Notch2 increased in pulp stroma surrounded by coronal odontoblasts. Notch1 and, especially, Notch3 expression increased, corresponding to perivascular cell groups. A low increase of ligand expression was observed near the injury with Delta1 expression along the dentin wall and Jagged1 in the stroma. Expression of the downstream target, Hes1, was observed along the lesion and adjacent dentin walls. Hes5 expression was not observed. The results indicate that Notch signaling is activated in response to injury and associated with the differentiation of pulp cells into perivascular cells and odontoblasts. The findings are consistent with the concept that the Notch pathway controls stem cell fate during pulp regeneration.

Animals↗

PubMed2005

Identification of eight genes that are potentially involved in tamoxifen sensitivity in breast cancer cells.

Although the antiestrogen agent tamoxifen has long been used to treat women with hormone receptor positive invasive breast carcinoma, the mechanisms of its action and acquired resistance to tamoxifen during treatment are largely unknown. A number of studies have revealed that over-activation of some signaling pathways can cause tamoxifen resistance; however, very little information is available regarding the genes whose loss-of-function alternation contribute to tamoxifen resistance. Here we used a forward genetic approach in vitro to generate tamoxifen resistant cells from the tamoxifen sensitive breast cancer cell line ZR-75-1, and further identified the disrupted gene in different tamoxifen resistant clones. Retinol binding protein 7, DNA polymerase-transactivated protein 3, g-glutamyltransferase-like activity 1, slit-robo RhoGTPase-activating protein, tetraspan NET-4, HSPC194, amiloride-sensitive epithelial sodium channel gene, and Notch2, were the eight mutated genes identified in different tamoxifen resistant clones, suggesting their requirement for tamoxifen sensitivity in ZR-75-1 cells. Since the functions of these genes are not related to each other, it suggests that multiple pathways can influence tamoxifen sensitivity in breast cancer cells.

Base Sequence↗

PubMed2003

Long-lasting induction of Notch2 in the hippocampus of kainate-treated adult mice.

Notch proteins are involved in cell fate specification during development in tissues including brain. Little is known about their function in adulthood. Recently, Notch receptors have been hypothesized to play a role in neurodegeneration and in particular in Alzheimer's disease (Notch1) and CADASIL (Notch3). Here we show that another family member (Notch2) is constitutively expressed in adult mouse hippocampus in DG and not in CA1 and CA3 neurons. Treatment with kainic acid resulted in marked Notch2 induction in pyramidal neurons of CA1 and in a subpopulation of CA3 neurons surviving the lesion and protein expression was still detectable 6 weeks after drug treatment. These results suggest Notch2 involvement in the response of postmitotic neurons to excitotoxic stimuli.

Animals↗

PubMed2001

Expression patterns of Notch1, Notch2, and Notch3 suggest multiple functional roles for the Notch-DSL signaling system during brain development.

The Notch-DSL signaling system consists of multiple receptors and ligands, and plays many roles in development. The function of Notch receptors and ligands in mammalian brain, however, is poorly understood. In the current study, we examined the expression patterns for three receptors of this system, Notch1, 2, and 3, in late embryonic and postnatal rat brain by in situ hybridization. The three receptors have overlapping but different patterns of expression. Messenger RNA for all three proteins is found in postnatal central nervous system (CNS) germinal zones and, in early postnatal life, within numerous cells throughout the CNS. Within zones of cellular proliferation of the postnatal brain, Notch1 mRNA is found in both the subventricular and the ventricular germinal zones, whereas Notch2 and Notch3 mRNAs are more highly localized to the ventricular zones. Both Notch1 and Notch3 mRNAs are expressed along the inner aspect of the dentate gyrus, a site of adult neurogenesis. Notch2 mRNA is expressed in the external granule cell layer of the developing cerebellum. In several brain areas, Notch1 and Notch2 mRNAs are relatively concentrated in white matter, whereas Notch3 mRNA is not. Neurosphere cultures (which contain CNS stem cells), purified astrocyte cultures, and striatal neuron-enriched cultures express Notch1 mRNA. However, in these latter cultures, Notch1 mRNA is produced by nestin-containing cells, rather than by postmitotic neurons. Taken together, these results support multiple roles for Notch1, 2, and 3 receptor activation during CNS development, particularly during gliogenesis.

Animals↗

PubMed2002

Notch2 is involved in the overexpression of CD23 in B-cell chronic lymphocytic leukemia.

Members of the Notch family encode transmembrane receptors that modulate differentiation, proliferation, and apoptotic programs of many precursor cells, including hematopoietic progenitors. Stimulation of Notch causes cleavage followed by translocation of the intracellular domain (NotchIC) to the nucleus, where it activates transcription of CBF1 responsive genes. The aim of this study was to elucidate the mechanisms leading to the overexpression of CD23, a striking feature of B-cell chronic lymphocytic leukemia (B-CLL) cells. By electrophoretic mobility shift assays, we identified a transcription factor complex (C1) that binds sequence specific to one known and 4 newly identified putative CBF1 recognition sites in the CD23a core promoter region. With the use of Epstein-Barr virus (EBV)-infected B cells as a model for CBF1 mediated CD23a expression, C1 was found to be EBV inducible. Supershift assays revealed that the nuclear form of Notch2 is a component of C1 in B-CLL cells, supporting a model in which NotchIC activates transcription by binding to CBF1 tethered to DNA. Transient transfection of REH pre-B cells with an activated form of Notch2 induced endogenous CD23a, confirming that CD23a is a target gene of Notch2 signaling. Finally, reverse transcription-polymerase chain reaction and kinetic analysis demonstrated that the Notch2 oncogene is not only overexpressed in B-CLL cells but might also be related to the failure of apoptosis characteristic for this disease. In conclusion, these data suggest that deregulation of Notch2 signaling is involved in the aberrant expression of CD23 in B-CLL.

Apoptosis↗

PubMed2006

Lack of evidence that bone marrow cells contribute to cholangiocyte repopulation during experimental cholestatic ductal hyperplasia.

BACKGROUND: Ductopenia is observed in end-stage human cholestatic diseases. The limited capability of cholangiocytes for proliferation is suggested to be the principal reason. Recently, bone marrow cells (BMCs) have been reported to behave as hepatic stem cells; however, their capability to differentiate into cholangiocytes in cholestasis remains unclear. METHODS: Normal mice were lethally irradiated to suppress the proliferation of self-BMCs; thereafter, the BMCs from enhanced green fluorescent protein (EGFP)-transgenic mice were transferred to recipients. Chronic cholestasis was induced by 0.1%alpha-naphtylisothiocyanate (ANIT) feeding. The proliferation of cholangiocytes and oval cells was assessed morphologically and immunohistchemically (cytokeratin-7 (CK-7), A6). Proliferative activity (proliferating cell nuclear antigen (PCNA) protein expression), hepatic growth factor (HGF) receptor (c-Met), stem cell factor receptor (c-kit), Notch2 and Hes1 expression were also evaluated. RESULTS: Marked cholangiocyte proliferation was observed in ANIT-fed mice. However, no EGFP/CK-7 double positive cells were identified in any of the liver specimens after BMCs transfer (Tx). In hepatic parenchyma, there were scattered EGFP-positive cells, although none of them were positive for CK-7. CONCLUSIONS: In spite of the significant ductular proliferations after ANIT feeding, no EGFP-positive cholangiocytes were confirmed by any other means in this chronic cholestasis model. Thus, different from hepatocytes, BMCs Tx seems not to contribute to the differentiation of cholangiocytes. Future studies are feasible to clarify the origin of proliferative cholangiocytes observed in this chronic cholestatic ductular hyperplasia model.

1-Naphthylisothiocyanate↗

PubMed2000

Binding of Delta1, Jagged1, and Jagged2 to Notch2 rapidly induces cleavage, nuclear translocation, and hyperphosphorylation of Notch2.

Delta1, Jagged1, and Jagged2, commonly designated Delta/Serrate/LAG-2 (DSL) proteins, are known to be ligands for Notch1. However, it has been less understood whether they are ligands for Notch receptors other than Notch1. Meanwhile, ligand-induced cleavage and nuclear translocation of the Notch protein are considered to be fundamental for Notch signaling, yet direct observation of the behavior of the Notch molecule after ligand binding, including cleavage and nuclear translocation, has been lacking. In this report, we investigated these issues for Notch2. All of the three DSL proteins bound to endogenous Notch2 on the surface of BaF3 cells, although characteristics of Jagged2 for binding to Notch2 apparently differed from that of Delta1 and Jagged1. After binding, the three DSL proteins induced cleavage of the membrane-spanning subunit of Notch2 (Notch2(TM)), which occurred within 15 min. In a simultaneous time course, the cleaved fragment of Notch2(TM) was translocated into the nucleus. Interestingly, the cleaved Notch2 fragment was hyperphosphorylated also in a time-dependent manner. Finally, binding of DSL proteins to Notch2 also activated the transcription of reporter genes driven by the RBP-Jkappa-responsive promoter. Together, these data indicate that all of these DSL proteins function as ligands for Notch2. Moreover, the findings of rapid cleavage, nuclear translocation, and phosphorylation of Notch2 after ligand binding facilitate the understanding of the Notch signaling.

Animals↗

PubMed2007

Notch signaling in gastrointestinal tract (review).

Notch signaling is one of key pathways constituting the stem cell signaling network. DLL1, DLL3, DLL4, JAG1 and JAG2 with DSL domain are typical Notch ligands, while DNER, F3/Contactin and NB-3 without DSL domain are atypical Notch ligands. Notch-ligand binding to NOTCH1, NOTCH2, NOTCH3 or NOTCH4 receptor induces the receptor proteolysis by metalloprotease and gamma-secretase to release Notch intracellular domain (NICD). Typical Notch ligands transduce signals to the CSL-NICD-Mastermind complex for the maintenance of stem or progenitor (transit-amplifying) cells through transcriptional activation of HES1, HES5, HES7, HEY1, HEY2 and HEYL genes, and also to the NF-kappaB-NICD complex for the augmentation of NF-kappaB signaling. Atypical Notch ligands transduce signals to the CSL-NICD-Deltex complex for the differentiation of progenitor cells through MAG transcriptional activation. Notch signals are transduced to the canonical pathway (CSL-NICD-Mastermind signaling cascade) or the non-canonical pathway (NF-kappaB-NICD and CSL-NICD-Deltex signaling cascades) based on the expression profile of Notch ligands, Notch receptors, and Notch signaling modifiers. Canonical Notch signaling is activated in the stem or progenitor domain of gastrointestinal epithelium, such as basal layer in esophagus and lower part of the crypt in colon. Notch signaling to inhibit secretory cell differentiation is oncogenic in gastric cancer and colorectal cancer, while Notch signaling to promote keratinocyte differentiation is anti-oncogenic in esophageal squamous cell carcinoma (SCC). Single nucleotide polymorphism (SNP), epigenetic change, and genetic alteration of genes encoding Notch signaling-associated molecules will be utilized as biomarkers for gastrointestinal cancer. gamma-Secretase inhibitors, functioning as Notch signaling inhibitors, will be applied as anti-cancer drugs for gastric cancer and colorectal cancer.

Gastrointestinal Neoplasms↗

PubMed2000

Correlation of asymmetric Notch2 expression and mouse incisor rotation.

Notch signaling defines an evolutionarily conserved cell communication mechanism, which enables neighboring cells to adopt different fates. Furthermore, Notch signaling may create boundaries that direct both the growth and patterning of the developing organs. Here we report on the expression of Notch receptors during the development of rodent incisors. Before the acquisition of their characteristic shape, incisors rotate antero-posteriorly and become asymmetric at their labial-lingual axis. Notch2 is expressed only in the anterior part of the developing incisors, well before their rotation, while Notch2 expression was symmetrical in the developing molars. This is the first demonstration of an asymmetric gene expression pattern during the rotation of the rodent incisors.

Animals↗

PubMed2002

Characterization of Notch receptor expression in the developing mammalian heart and liver.

Alagille syndrome (AGS) is an autosomal dominant disorder characterized by bile duct paucity along with cardiovascular, skeletal, and ophthalmologic defects. The identification of JAG1 as the AGS disease gene revealed the crucial role of the Notch signaling pathway in the development of multiple organ systems in humans. Patients with identical mutations in JAG1 demonstrate extreme clinical variability, suggesting that other factors may influence the severity of the developmental defects in this disorder. We have defined the temporal and spatial expression patterns of the Notch receptor genes in the developing mammalian heart and liver in order to identify potential ligand/receptor interactions during embryogenesis. In the developing heart, both Notch1 and Notch2 are expressed in the outflow tracts and the epicardium, in specific cell populations previously shown to express JAG1. These cells are destined to undergo epithelial-to-mesenchymal transformation. In the newborn mouse liver, Notch2 and Notch3 are expressed in opposing cell populations, suggesting they play different roles in cell fate determination during bile duct development. JAG1 is also expressed in cells adjacent to those expressing Notch2, suggesting a possible ligand receptor relationship. The Notch receptors have distinct roles in cell fate determination in different organ systems.

Animals↗

PubMed2002

A mouse model of Alagille syndrome: Notch2 as a genetic modifier of Jag1 haploinsufficiency.

Alagille syndrome is a human autosomal dominant developmental disorder characterized by liver, heart, eye, skeletal, craniofacial and kidney abnormalities. Alagille syndrome is caused by mutations in the Jagged 1 (JAG1) gene, which encodes a ligand for Notch family receptors. The majority of JAG1 mutations seen in Alagille syndrome patients are null alleles, suggesting JAG1 haploinsufficiency as a primary cause of this disorder. Mice homozygous for a Jag1 null mutation die during embryogenesis and Jag1/+ heterozygous mice exhibit eye defects but do not exhibit other phenotypes characteristic of Alagille syndrome patients ( Xue, Y., Gao, X., Lindsell, C. E., Norton, C. R., Chang, B., Hicks, C., Gendron-Maguire, M., Rand, E. B., Weinmaster, G. and Gridley, T. (1999) HUM: Mol. Genet. 8, 723-730). Here we report that mice doubly heterozygous for the Jag1 null allele and a Notch2 hypomorphic allele exhibit developmental abnormalities characteristic of Alagille syndrome. Double heterozygous mice exhibit jaundice, growth retardation, impaired differentiation of intrahepatic bile ducts and defects in heart, eye and kidney development. The defects in bile duct epithelial cell differentiation and morphogenesis in the double heterozygous mice are similar to defects in epithelial morphogenesis of Notch pathway mutants in Drosophila, suggesting that a role for the Notch signaling pathway in regulating epithelial morphogenesis has been conserved between insects and mammals. This work also demonstrates that the Notch2 and Jag1 mutations interact to create a more representative mouse model of Alagille syndrome and provides a possible explanation of the variable phenotypic expression observed in Alagille syndrome patients.

Alagille Syndrome↗

PubMed2006

Visualization of APP dimerization and APP-Notch2 heterodimerization in living cells using bimolecular fluorescence complementation.

We previously demonstrated that the amyloid precursor protein (APP) interacts with Notch receptors. Here, we confirmed the APP/Notch1 endogenous interaction in embryonic day 17 rat brain tissue, suggesting the interaction was not as a result of over-expression artifacts. To investigate potential homodimeric and heterodimeric interactions of APP and Notch2 (N2), we have visualized the subcellular localization of the APP/N2 complexes formed in living cells using bimolecular fluorescence complementation (BiFC) analysis. BiFC was accomplished by fusing the N-terminal fragment or the C-terminal fragment of yellow fluorescent protein (YFP) to APP, N2, and a C-terminally truncated form of N2. When expressed in COS-7 cells, these tagged proteins alone did not produce a fluorescent signal. The tagged APP homodimer produced a weak fluorescent signal, while neither full-length N2, nor a truncated N2 alone, produced a visible signal, suggesting that N2 receptors do not form homodimers. The strongest fluorescent signal was obtained with co-expression of the C-terminal fragment of YFP fused to APP and the N-terminal fragment of YFP fused to the truncated form of N2. This heterodimer localized to plasma membrane, endoplasmic reticulum (ER), Golgi and other compartments. The results were confirmed and quantified by flow cytometry. The BiFC method of specifically visualizing APP/Notch interactions can be applied to study APP and Notch signaling during development, aging and neurodegeneration.

Alzheimer Disease↗

PubMed2005

Autosomal-dominant familial hematuria with retinal arteriolar tortuosity and contractures: a novel syndrome.

BACKGROUND: Autosomal-dominant forms of hematuria have been mostly related to mutations in the COL4A3/COL4A4 genes. Patients with thin basement membrane (BM) disease do not have extrarenal manifestations, while those with Alport syndrome often present with hearing loss, anterior lenticonus, and dot-and-fleck retinopathy. METHODS: We performed a phenotypic study and a candidate gene approach in a four-generation family presenting with autosomal-dominant hematuria associated with extrarenal manifestations. Renal biopsy was analyzed for determination of BM thickness and expression of chains of type IV collagen. Linkage to 18 candidate genes/loci was investigated using polymorphic microsatellite markers. RESULTS: In all affected patients, hematuria without proteinuria was associated with muscular contractures and retinal arterial tortuosities responsible for retinal hemorrhages. Cardiac arrhythmia, Raynaud phenomena, and brain MRI abnormalities were also observed. Despite the presence of red cells in tubule sections, no glomerular abnormalities were found by electron microscopy. Expression of type IV collagen chains and glomerular BM thickness was normal. We searched for a molecular defect affecting either BM or angiogenesis. Linkage analyses of genes encoding BM components (COL4A3/COL4A4, COL6A1, COL6A2, COL6A3, FBLN1), and angiogenic factors or their receptors (VHL, ANPT1, ANPT2, TIE, TEK, NOTCH2, NOTCH3, NOTCH4, DLL4, JAG1, JAG2) and of the facio-sapulo-humeral dystrophy and 3q21 loci failed to show segregation of the disease with those gene loci. CONCLUSION: We have identified a new inherited hematuria syndrome associated with retinal vessel tortuosities and contractures. We recommend performing a fundus examination in patients with familial hematuria and episodes of visual impairment, as well as a urinary analysis in patients with retinal arterial tortuosity or congenital muscular contractures.

Collagen Type IV↗

PubMed1992

Notch2: a second mammalian Notch gene.

Notch is a cell surface receptor that mediates a wide variety of cellular interactions that specify cell fate during Drosophila development. Recently, homologs of Drosophila Notch have been isolated from Xenopus, human and rat, and the expression patterns of these vertebrate proteins suggest that they may be functionally analogous to their Drosophila counterpart. We have now identified a second rat gene that exhibits substantial nucleic and amino acid sequence identity to Drosophila Notch. This gene, designated Notch2, encodes a protein that contains all the structural motifs characteristic of a Notch protein. Thus, mammals differ from Drosophila in having more than one Notch gene. Northern and in situ hybridisation analyses in the developing and adult rat identify distinct spatial and temporal patterns of expression for Notch1 and Notch2, indicating that these genes are not redundant. These results suggest that the great diversity of cell-fate decisions regulated by Notch in Drosophila may be further expanded in vertebrates by the activation of distinct Notch proteins.

Amino Acid Sequence↗

PubMed2003

From the yolk sac to the spleen: New roles for Notch in regulating hematopoiesis.

Although Notch receptors are widely expressed during hematopoiesis, their roles outside of the T cell lineage are not well characterized. Two reports in this issue of Immunity show that Notch1 and Notch2, respectively, are required to generate the earliest embryonic hematopoietic stem cells and splenic marginal zone B cells. Thus, different Notch receptors have specific and nonoverlapping functions that influence multiple hematopoietic lineages at various stages of development.

Animals↗

PubMed2006

Notch3 signaling initiates choroid plexus tumor formation.

Notch3 has been studied in the context of brain development, but whether it plays a role in the formation of brain tumors is unclear. We demonstrate that the introduction of constitutively active Notch3 into periventricular cells of embryonic day 9.5 mice causes the formation of choroid plexus tumors (CPTs). Tumors arose in the fourth ventricles in 83% of animals and were associated with hydrocephalus. They were microscopically highly similar to choroid plexus papillomas in humans, with an ongoing proliferation rate of 4-6%. Signs of Notch pathway activity were also present in human choroid plexus lesions, and receptor mRNA levels in papillomas were elevated over those in non-neoplastic choroid plexus. Notch2 was overexpressed approximately 500-fold in one case, suggesting that the role of this pathway in CPTs may not be specific to Notch3. Our findings indicate that activated Notch3 can function as an oncogene in the developing brain, and link the Notch pathway to human CPT pathogenesis.

Animals↗

PubMed2004

Math1 controls cerebellar granule cell differentiation by regulating multiple components of the Notch signaling pathway.

Cerebellar granule cells (CGC) are the most abundant neurons in the mammalian brain, and an important tool for unraveling molecular mechanisms underlying neurogenesis. Math1 is a bHLH transcription activator that is essential for the genesis of CGC. To delineate the effects of Math1 on CGC differentiation, we generated and studied primary cultures of CGC progenitors from Math1/lacZ knockout mice. Rhombic lip precursors appeared properly positioned, expressed CGC-specific markers, and maintained Math1 promoter activity in vivo and in vitro, suggesting that Math1 is not essential for the initial stages of specification or survival of CGC. Moreover, the continuous activity of Math1 promoter in the absence of MATH1, indicated that MATH1 was not necessary for the activation of its own expression. After 6, but not 3, days in culture, Math1 promoter activity was downregulated in control cultures, but not in cells from Math1 null mice, thus implying that Math1 participates in a negative regulatory feedback loop that is dependent on increased levels of MATH1 generated through the positive autoregulatory feedback loop. In addition, Math1 null CGC did not differentiate properly in culture, and were unable to extend processes. All Notch signaling pathway receptors and ligands tested were expressed in the rhombic lip at embryonic date 14, with highest levels of Notch2 and Jag1. However, Math1-null rhombic lip cells presented conspicuous downregulation of Notch4 and Dll1. Moreover, of the two transcriptional repressors known to antagonize Math1, Hes5 (but not Hes1) was downregulated in Math1-null rhombic lip tissue and primary cultures, and was shown to bind MATH1, thus revealing a negative regulatory feedback loop. Taken together, our data demonstrate that CGC differentiation, but not specification, depends on Math1, which acts by regulating the level of multiple components of the Notch signaling pathway.

Animals↗