Role Of Notch Signaling Pathway Research Articles

μ Opioid Receptor-Triggered Notch-1 Activation Contributes to Morphine Tolerance: Role of Neuron-Glia Communication.

The development of analgesic tolerance to opioids is an important limitation in the management of chronic pain. Spinal cord glial cell activation appears to play a pivotal role in the development and maintenance of opioid tolerance, indicating the presence of an opioid-induced neuronal-glial interaction; however, how opioids drive this cross-talk is still elusive. In search of treatments to attenuate morphine analgesic tolerance, our research focused on the role of Notch signaling pathway, one of the most important mechanisms of cell-to-cell interactions, in the spinal dorsal horn after morphine repeated exposure and whether Notch inhibition attenuates morphine analgesic tolerance. Double immunofluorescence experiments on spinal sections from morphine-tolerant mice showed a neuronal localization of Notch-1 receptor whereas the Notch ligand Jagged was localized on neighboring astrocytes. Morphine-induced μ opioid receptor (MOR) stimulation triggered Notch-1 signaling activation and this event was mediated by astrocyte JNK activation. Notch-1 activation selectively reduced the expression of histone deacetylase (HDAC)-1, resulting in an overphosphorylation of PKC and ERK, kinases involved in MOR phosphorylation and internalization after repeated morphine exposure. Notch-1 signaling inhibition, through intrathecal administration of the γ-secretase inhibitor, DAPT, counteracted PKC and ERK overphosphorylation, MOR internalization, and analgesic tolerance. Conversely, the HDAC-1 inhibitor, LG325, further aggravated MOR internalization, PKC overphosphorylation, and analgesic tolerance.Our findings implicate the MOR-triggered Notch-1 signaling in promoting MOR internalization and morphine analgesic tolerance by epigenetic regulation mechanisms. These data suggest that Notch-1 inhibitors could represent an innovative therapeutic perspective for the management of opioid tolerance in chronic pain therapy.

Role of Notch signaling pathway in bone marrow mesenchymal stem cell therapy for phosgene inhalationinduced lung injury in rats

Purpose: To determining the expression and role of the Notch signaling pathway (NSP) in phosgene inhalation-induced lung injury in rats, and the therapeutic effect of bone marrow mesenchymal stem cell (MSC) on the lung lesions.Methods: Wistar rats (220 - 280 g) were randomly assigned to air inhalation group, phosgene inhalation group, and mesenchymal stem cell (MSC) intervention group. Each group had 8 rats. Directional flow phosgene inhalation device was used to produce phosgene inhalation-induced lung injury in the rats. Serum inflammatory cytokines (TNF-α, IL-8 and IL-6) were determined using ELISA assay kits. The expressions of proteins related to the NSP (Notch1, Notch2, Hes1, Hes5) were quantified using Western blot.Results: Phosgene inhalation brought about significant increase in TNF-α, IL-8 and IL-6 levels (p < 0.01), but MSC intervention significantly reduced the expressions of these inflammatory factors to varying degrees (p < 0.05), although their levels were still significantly high, relative to the air inhalation group. Results from western blot showed that the Notch1, Notch2, Hes1 and Hes5 were upregulated in the phosgene inhalation group, when relative to the air inhalation group (p < 0.01). Protein expressions in the MSC intervention group were lower than those in the non-intervention groups (p < 0.05).Conclusion: Phosgene inhalation activates Notch signaling pathway, while MSC intervention inhibits this signaling pathway. Thus, inhibition of NSP may be implicated in the protective effect of MSC therapy against phosgene-induced lung injury.Keywords: Phosgene, Lung injury, Notch signalling pathway, Mesenchymal stem cells

Role of Notch Signaling Pathway in Glioblastoma Pathogenesis.

Notch signaling is an evolutionarily conserved pathway that regulates important biological processes, such as cell proliferation, apoptosis, migration, self-renewal, and differentiation. In mammals, Notch signaling is composed of four receptors (Notch1–4) and five ligands (Dll1-3–4, Jagged1–2) that mainly contribute to the development and maintenance of the central nervous system (CNS). Neural stem cells (NSCs) are the starting point for neurogenesis and other neurological functions, representing an essential aspect for the homeostasis of the CNS. Therefore, genetic and functional alterations to NSCs can lead to the development of brain tumors, including glioblastoma. Glioblastoma remains an incurable disease, and the reason for the failure of current therapies and tumor relapse is the presence of a small subpopulation of tumor cells known as glioma stem cells (GSCs), characterized by their stem cell-like properties and aggressive phenotype. Growing evidence reveals that Notch signaling is highly active in GSCs, where it suppresses differentiation and maintains stem-like properties, contributing to Glioblastoma tumorigenesis and conventional-treatment resistance. In this review, we try to give a comprehensive view of the contribution of Notch signaling to Glioblastoma and its possible implication as a target for new therapeutic approaches.

The Significance of NOTCH Pathway in the Development of Fibrosis in Systemic Sclerosis.

Systemic sclerosis (SSc) is an autoimmune disorder characterized by the fibrosis of skin, heart, lung, and kidney as well. Excessive activation of fibroblasts is associated with higher expression of Notch1 and/or Notch3 genes. The constitutive expression of NOTCH genes was described in epithelial cells: epidermal keratinocytes, hair follicle cells and sebaceous glands. The NOTCH signalling pathway may be involved in the development of fibrosis, myofibroblast formation and the process of epithelial-mesenchymal transition. Activation of the NOTCH pathway leads to morphological, phenotypic and functional changes in epithelial cells. Furthermore, inhibition of Notch signalling prevent the development of fibrosis in different models, among them, bleomycin-induced fibrosis and in the Task-1 mause model. Molecular mechanisms, including the role of NOTCH signaling pathway, associated with fibrosis in SSc have not been completely recognized.

Notch signaling promotes serrated neoplasia pathway in colorectal cancer through epigenetic modification of EPHB2 and EPHB4.

BackgroundDysregulation of erythropoietin-producing hepatoma (Eph) proteins in human cancers is extensively documented but not clear in colorectal cancer (CRC). In this study, we aimed to investigate the role of Notch signaling pathway and epigenetic modification of EPHB2 and EPHB4 expression in serrated neoplasia development.MethodsThe expression of EPHB2 and EPHB4 in CRC clinical specimens and cell lines were determined by immunohistochemistry, Western blot, and real-time PCR. Cell proliferation and invasion were evaluated by MTT and chamber kits, luciferase assay and co-immunoprecipitation were used to detect the transcriptional regulation and protein–protein interactions, respectively. The immunofluorescence assay was employed to confirm the subcellular location of Notch intracellular domain (NICD), and chromatin immunoprecipitation assay was implied to detect the modification types of H3K4me3 and H3K27me3. Mice xenograft model was used to detect the in vivo effects of EPHB2 and EPHB4 genes on cell growth.ResultsIn CRC clinical specimens and cell lines, we found that EPHB2 was significantly decreased, while EPHB4 was elevated in the CRC tissues, and these aberrant expression manners correlated with worse overall survival rates in the clinic. When the EPHB2 and EPHB4 expressions were manipulated by overexpression or knockdown in the SW620 cells, the cell proliferation and invasion were obviously suppressed, whereas EPHB2 knockdown or EPHB4 overexpression showed the opposite phenotypes. We also found that Notch signaling pathway was abnormally activated and treatment of Notch signaling ligand human Jagged1 peptide downregulated EPHB2 and upregulated EPHB4 in the SW620 cells, as well as promoted the chromatin modification protein Jumonji domain-containing protein-3 (JMJD3) cytonuclear trans-localization with the NICD, which indicated that NICD brought JMJD3 to the EPHB4 enhancer region to decrease the H3K27me3 level.ConclusionTaken together, we provide a new mechanistic option in understanding the role of Notch signaling and the roles of EPHB2 and EPHB4 in CRC.

Roles of notch signaling pathway and endothelial-mesenchymal transition in vascular endothelial dysfunction and atherosclerosis.

To investigate the role of the Notch signaling pathway on the endothelial-mesenchymal transition (EndMT) during vascular endothelial dysfunction and atherosclerosis. Human coronary artery endothelial cells (HCAEC) were treated with the exogenous Notch homolog 1 (Notch1) factor to activate the Notch1 pathway, and cells were then observed under the microscope for morphologic changes. Changes in the expression of related proteins were detected by Western blot. In vivo experiments were performed using 18 Sprague Dawley® (SD) rats, and GSI factor was used to specifically inhibit Notch pathway activation. Rats were used and randomly divided into three groups: normal diet (ND) group, high-fat diet (HFD) group, and high-fat diet + GSI (HFD+GSI) group, 6 rats in each group. Hematoxylin and eosin (H&E) staining was used to examine the cardiac aortic morphology of the rats in each treatment group. Real-time polymerase chain reaction (RT-PCR) and Western blot were used to detect the expression of Notch1, Hes1, VE-cadherin and α-SMA in the aortic tissues of rats in each group at mRNA and protein levels, respectively. After HCAECs were treated with Notch1, endothelial protein levels of VE-cadherin were significantly decreased and levels of the interstitial protein α-SMA were significantly increased. In the animal model, the rats fed with high-fat diet for two months presented obvious atherosclerosis spots in their aorta, but those fed with the same diet and treated with GSI inhibitor of Notch pathway showed significantly fewer atherosclerosis signs. Compared with ND group, mRNA and protein expression levels of Notch1, Hes1 and α-SMA were significantly increased, and the expression levels of endothelial marker VE-cadherin were significantly decreased in aortas of rats in HFD group. Compared with the rats in HFD group, the rats in HFD+GSI group showed significantly reduced expression levels of Notch1, Hes1 and α-SMA. The activation of Notch signaling pathway can induce the EndMT progression and promote the development of atherosclerotic lesions.

EGFL7 silencing inactivates the Notch signaling pathway; enhancing cell apoptosis and suppressing cell proliferation in human cutaneous melanoma.

Melanoma is the main cause of death in patients with skin cancer. While the pathogenesis of cutaneous melanoma is poorly understood, increasing evidence shows that epidermal growth factor (EGF) may be involved. Herein, we tested the hypothesis that down-regulation of EGFL7 inhibits development and progression of human cutaneous melanoma (CM). Initially, we performed immunohistochemical analysis of EGFL7 in 130 specimens and the findings indicated that EGFL7 was highly expressed in CM. The expressions of EGFL7 and Notch signaling pathway-related genes in CM were then measured by reverse transcription quantitative polymerase chain reaction (RT-qPCR) and Western blot assay. In order to assess biological functions of EGFL7 in CM we up-regulated or down-regulated endogenous EGFL7 using EGFL7-OE or shRNA against EGFL7 in the A375 CM cell line. To better understand the pivotal role of Notch signaling pathway in CM, we blocked this pathway in A375 cells by inhibitor treatment. Finally, tumor xenograft in nude mice was performed to test the in vivo tumorigenesis of the transfected A375 cells. While EGFL7 activated the Notch signaling pathway in CM, gain- and loss-of-function studies established that decreased EGFL7 inhibited cell proliferation and promoted apoptosis in A375 cells. Moreover, down-regulated EGFL7 suppressed in vivo tumorigenesis. Most importantly, we determined that down-regulating EGFL7 inhibited CM development by suppressing the Notch signaling pathway. The combined findings define potential roles of decreased EGFL7 as inhibitors of CM development by suppressing the Notch signaling pathway, and EGFL7 may therefore be a novel therapeutic target in cutaneous melanoma patients.

Notch signaling pathway suppresses CD8+ T cells activity in patients with lung adenocarcinoma

Evolution and progression of cancer always leads to CD8+ T cells dysfunction/exhaustion. Controversy remains as to the role of Notch signaling pathway in CD8+ T cells regulation in tumorigenesis. Thus, the aim of this study was to investigate the immunomodulatory activity of Notch signaling pathway to peripheral and lung-resident CD8+ T cells in patients with lung adenocarcinoma. Forty-eight lung adenocarcinoma patients and twenty healthy individuals were enrolled in the current study, and CD8+ T cells were purified from both peripheral bloods and bronchoalveolar lavage fluids. Notch receptor mRNA expression was semi-quantified by real-time PCR. Cytolytic and noncytolytic activity of CD8+ T cells evaluated in direct and indirect contact co-culture with A549 cells in response to Notch signaling inhibition by measuring of lactate dehydrogenase release and cytokines production. Expression of Fas ligand (FasL), perforin, and granzyme B were also assessed by flow cytometry. Notch2 mRNA expression was elevated in both peripheral and lung-resident CD8+ T cells in lung adenocarcinoma patients, however, did not correlated with tumor stages or epidermal growth factor receptor mutation. Peripheral CD8+ T cells from healthy individuals exhibited stronger cytotoxicity in direct contact co-culture system, which was not influenced by Notch signaling inhibition. Moreover, suppression of Notch signaling augmented cytotoxicity of peripheral and lung-resident CD8+ T cells from lung adenocarcinoma patients in direct contact co-culture system, and promoted interferon-γ production in both systems. This process was accompanied by increased expression of FasL and perforin within CD8+ T cells. The current data revealed a potential immunosuppressive property of Notch signaling pathway to CD8+ T cells probably via inhibition of FasL and perforin in lung adenocarcinoma patients.

Notch signaling pathway regulates osteosarcoma stem cell characteristics by inhibiting Eph pathway

Objective To investigate the role of Notch signaling pathway to maintain the stem cell-like characteristics of osteosarcoma and its underlying mechanism. Methods Lentiviral NICD1 or Numb-shRNA was transduced into MG63 osteosarcoma cells to activate Notch activity in vitro. The impact of Notch on osteosarcoma stem cells were assessed by the tumor sphere formation assay and flow cytometry analysis of cell surface markers STRO-1/CD117. The expression of stem cell related genes (Sox2, Oct4) were evaluated by Western blot and qPCR. The nude mice were randomly divided into 3 groups: the NICD1 overexpression (NICD-OE) group, the DAPT group and the control (CON) group. The tumor growth was monitored for 8 weeks and the tumor volume and weight were recorded weekly. To investigate whether Notch regulates Eph pathway, Eph pathway related protein EphB, p-EphB was measured by Western blot. The impact of ephrinB1 on NICD overexpression cell were assessed by tumor sphere formation assay. The expression of Sox2 and Oct4 was evaluated by Western blot. Results NICD1 overexpression or Numb-shRNA increased the activity of Notch pathway. The Notch-activated osteosarcoma showed enhanced in vitro tumor spheroid formation capacity, increased Stro-1/CD117double positive ratio, and upregulated expression of Sox2 and Oct4 in vitro. In animal experiments, it was found that activation of Notch pathway promoted tumor formation in vivo and Notch inhibition decreased it. The primary osteosarcoma cells were obtained from mice xenograft treated with DAPT and its tumor sphere formation capacity was significantly reduced. Finally, The Notch pathway inhibits the phosphorylation of EphB, as well as the downstream signal pathway of EphB, but there is no significant change in total EphB. The activation of Eph pathway inhibited Notch induced up-regulation of tumor sphere formation and Sox2 and Oct4 expression. Conclusion Notch signaling pathway maintains the stem cell-like characteristics of osteosarcoma probably by inhibiting the Eph pathway. Key words: Osteosarcoma; Cancer stem cell; Receptor, Notch1; Receptor, EphB1

Inhibition of notch signaling pathway temporally postpones the cartilage degradation progress of temporomandibular joint arthritis in mice

PurposeThe aim of this study is to explore the role of Notch signaling pathway in the initiation and progression of temporomandibular joint osteoarthritis (TMJOA). Methods48 mice were divided into DAPT-TMJOA, Control-TMJOA and Control-Sham groups. Animals received discectomy/Sham surgery in their right TMJ, following the DAPT/saline intra-articular injections every week. Mice were sacrificed at 1/4/8 weeks post-surgery. Safranin-O and H&E staining were performed on the TMJ sections for the modified Mankin's score. qPCR and immunohistochemistry were used to evaluate Notch1, Jagged1 and Hes5 expressions. ResultsThe mRNA expressions of Notch1, Jagged1 and Hes5 were significantly increased in Control-TMJOA group compared with Control-Sham group. Immunostaining revealed a dramatic elevation of Notch1, Jagged1 and Hes5 signals distributed in the cartilage at 1 and 4 weeks after discectomy. However, the increased number of those immuno-positive cells turned down at 8 weeks after surgery. DAPT treatment partially rescued the elevated mRNA expression and immuno-positive cell numbers of Notch1, Jagged1 and Hes5. More importantly, the cartilage destruction during TMJOA was delayed by DAPT treatment, analyzed by modified Mankin's score. ConclusionNotch signaling participates in the onset and development of TMJOA. Inhibiting Notch signaling activation by DAPT can partially delay the progress of TMJOA.

Effects of tumor necrosis factor-α on osteogenic differentiation and Notch signaling pathway in human periodontal ligament stem cells

To evaluate the effects of tumor necrosis factor-α (TNF-α) on osteogenic differentiation and Notch signaling pathway of periodontal ligament stem cells (PDLSCs) and to investigate the regulatory role of Notch signaling pathway on the osteogenic differentiation of PDLSCs under the influence of TNF-α. PDLSCs were obtained through enzyme digestion and tissue block method. The expression levels of stem cell surface markers CD105, CD90, CD146, CD45, and CD31 were detected by fluorescence activated cell sorter (FACS). PDLSCs were divided into experimental (10 ng·mL⁻¹ TNF-α) and control groups (0 ng·mL⁻¹ TNF-α). The proliferation ability of PDLSCs was detected using cell counting kit-8 (CCK-8). The effect of TNF-α on the osteogenic ability of PDLSCs were tested by measuring alkaline phosphatase (ALP) activity and conducting alizarin red staining and quantitative real-time polymerase chain reaction (PCR). We tested Notch signal pathway receptors Notch1, Notch2, ligand JAG1, JGA2, and downstream gene Hes-1. Changes in DLL1 expression were detected by quantitative real-time PCR. FACS profiling showed that PDLSCs were strongly positive for CD105, CD90, and CD146 but negative for CD45 and CD31. CCK-8 results showed that TNF-α could promote the proliferation of PDLSCs (P<0.05). ALP activity in the experimental group was lower than that in the control group (P<0.05). Alizarin red staining showed that the experimental group had decreased mineralized nodules as compared with the control group. Quantitative real-time PCR results showed that the mRNA expression of osteogenic marker genes cementum attachment protein (CAP), osteopontin (OPN), and Runt-related transcription factor 2 (Runx2) significantly decreased in the experimental group as compared with those in the control group (P<0.05). The expression levels of Notch1, Notch2, JAG1, JGA2 and Hes-1 were significantly decreased (P<0.05), whereas those of Notch3 and DLL1 were increased in Notch signaling pathway-related molecules (P<0.05). TNF-α can promote PDLSCs proliferation and inhibit bone differentiation and Notch signaling pathway expression, indicating that the Notch signaling pathway regulates PDLSCs osteogenic differentiation.

Notch signaling pathway dampens tumor-infiltrating CD8+ T cells activity in patients with colorectal carcinoma

CD8+ T cells play critical role in controlling the metastasis and prognosis of cancer. Controversy remains as to the contribution of Notch signaling pathway in modulation of CD8+ T cells activity and development of tumorigenesis. Thus, the aim of the current study was to investigate the immunoregulatory role of Notch signaling pathway to peripheral and tumor-infiltrating CD8+ T cells in patients with colorectal carcinoma. A total of 46 patients with colorectal carcinoma and 20 health individuals were enrolled, and CD8+ T cells were purified from both peripheral bloods and carcinoma specimens. Cytolytic and noncytolytic functions of CD8+ T cells in response to Notch signaling inhibition were evaluated by measurements of lactate dehydrogenase release and proinflammatory cytokines production in both direct and indirect contact co-culture system to target HT29 cells. Cellular proliferation and inhibitory receptors expression in CD8+ T cells were also assessed by CCK-8 method and flow cytometry. There was no remarkable difference in percentage of CD8+ T cells between healthy individuals and patients with colorectal carcinoma. Notch1/2 and Hes1/5 mRNAs were elevated expressed in tumor-infiltrating CD8+ T cells in patients with colorectal carcinoma, however, did not correlated with tumor differentiation or stages. CD8+ T cells from healthy individuals presented stronger cytotoxicity, which was not affected by Notch signaling inhibitor. Inhibition of Notch signaling pathway not only promoted cytotoxicity of tumor-infiltrating CD8+ T cells, but also enhanced proinflammatory cytokines (including IFN-γ, TNF-α, IL-1β, IL-6, and IL-8) production by CD8+ T cells from patients with colorectal carcinoma. This process was accompanied by decreased expression of PD-1 in CD8+ T cells without influencing cellular proliferation. Our results indicated a potential immunosuppressive property of Notch signaling pathway, which dampened both cytolytic and noncytolytic functions of CD8+ T cells probably via induction of PD-1 in patients with colorectal carcinoma.

A hypothetical role for Notch signaling pathway in immunopathogenesis of leprosy

Leprosy is a chronic infectious disease caused by Mycobacterium leprae mainly affecting skin and peripheral nerves. Leprosy has a broad range of clinical manifestations that range from mild (tuberculoid leprosy) to severe (lepromatous leprosy) forms, and are highly dependent on the host’s immune response. Among the immune response elements involved in the pathogenesis of leprosy are the Toll-like receptors (TLRs), vitamin D receptor (VDR), natural killer cells (NK), and T cells. These innate and adaptive immune response elements may be related to the Notch signaling pathway, which is involved in immune cell growth, differentiation, and proliferation. We hypothesize that failure in Notch signaling in leprosy patients may be associated to: 1) compromising NK cell maturation, lysing of infected cells, and CD4+ Th1 differentiation. 2) VDR alterations and TLR polymorphisms may affect expression of Notch Delta-like ligands (DLL) in antigen presenting cells (APCs). 3) altered DLL expression by APCs could compromise CD4+ T cell differentiation towards the Th1 and Th17 effector phenotypes; and finally 4) expression of Notch Jagged ligands would induce CD4+ T cell differentiation towards Th2 effector phenotype and alternative activation of macrophages. Altogether, these signaling failures could favor proliferation of M. leprae in the host. Therefore, evidence of the proposed immunologic failures in leprosy patients would be essential for the better understanding of immunopathogenesis of this disease, and would ultimately enable detection of susceptible individuals, providing a valuable tool for prevention of this debilitating disease.

Notch signaling pathway networks in cancer metastasis: a new target for cancer therapy.

Notch signaling pathway is evolutionarily conserved in mammals, which plays an important role in cell development and differentiation. In recent years, increasing evidence has shown that aberrant activation of Notch is associated with tumor process. Aberrant activation of Notch signaling pathway has been found in many different solid tumors can induce cell proliferation, metastasis and epithelial-mesenchymal transition. Notch receptor and its ligand are both single transmembrane protein, and Notch is activated when it binds to the Notch ligand of neighbor cells. The signal transduction of Notch signaling pathway is only between cells that are in contact with each other, which is independent of second messengers. Thus, Notch needs to cross talk with other signaling pathways, including PI3K/AKT, NF-κB, integrin and miRNAs, to precisely regulate cell fate. In this review, we summarize the roles of Notch signaling pathway in tumor metastasis and its regulatory mechanisms and discuss the current treatment strategies targeting Notch signal pathway.

The Notch signaling pathway in head and neck squamous cell carcinoma: A meta-analysis.

The Notch signaling pathway has been associated with the regulation of self-renewal capacity, cell cycle exit, and survival. However, the relationship between the Notch signaling pathway and HNSCC remains controversial. A meta-analysis was conducted to evaluate the role of Notch signaling pathway in HNSCC. Relevant studies published until March 31, 2015 were identified by searching the PubMed, EMBASE and Ovid database. A total of 9 articles were eligible for this meta-analysis. The meta-analysis results showed that the expression of Notch1, Notch3 and NICD was significantly higher in HNSCC as compared with control tissue. There was no significant difference in Jagged1 and HES1 expression between HNSCC and control tissue. Stratified analysis results showed that the expression of Notch1 was significantly higher in poor differentiation, III and IV stage and positive lymph node metastasis patients. Additionally, over-expression of Notch1, NICD, HES1 and DLL4 significantly predicted poor OS in HNSCC patients. The Notch signaling pathway plays an important role in tumor development of HNSCC. Inhibition of the Notch signaling pathway is a potential therapeutic method of HNSCC.

Role of Notch signaling pathway in the pathogenesis of infantile hemangioma

Infantile hemangioma is the most common benign neoplasm in infants. At present, studies are mostly limited to the molecular mechanism of the formation of infantile hemangioma, but the mechanism of its proliferation and regression is still unclear. It is considered that the occurrence of infantile hemangioma is related to abnormal proliferation of vascular endothelial cells and aberrant expression of cytokines, such as basic fibroblast growth factor (bFGF) and vascular endothelial growth factor (VEGF) . Recent studies have suggested that Notch signaling pathway plays an important role in the occurrence and development of infantile hemangioma. Notch signals participate in the proliferation and degeneration of infantile hemangioma by stimulating and regulating VEGF and its receptors as well as affecting the proliferation of vascular endothelial cells. Clarifying the role of Notch signaling pathway in the pathogenesis of infantile hemangioma will provide rational treatments of infantile hemangioma. Key words: Hemangioma; Infant; Signal transduction; Vascular endothelial growth factors; Notch signaling

The Role of the Notch Signal Pathway in Mucosal Cell Metaplasia in Mouse Acute Otitis Media

Otitis media (OM) is a major cause of morbidity in pediatric and adult patients. This inflammatory condition is characterized by mucous cell hyperplasia that is thought to produce mucins from the middle ear mucosa. We are interested in the role of Notch signalling pathway in this inflammatory process. Using an acute otitis media (AOM) mouse model through injection of Streptococcus Pneumoniae into the middle ear, histopathologic examination and quantitative RT-PCR, acute inflammation with the thickness of mucosa, Goblet cell hyperplasia, and cilia loss were determined and gene expression related to the Notch signaling pathway were evaluated. Upregulation of the mucous cell markers, Argr2 and Muc5AC, and downregulation of the cilia cell marker, Foxj1 and Dnai2, were observed in AOM. In addition, genes encoding Notch receptors and ligands (Notch1, Notch2, Notch3, Notch4 and Dll1) and the Notch target genes (Hes1, Hes5, Hey1, NRARP) in AOM decreased significantly. The expression of the Notch1 and Jagged1 also showed down-regulation throughout the mouse middle ear epithelium. Taken together, this study suggests that downregulation of the Notch signaling pathway is involved in the mucosa hyperplasia during AOM.

Notch signaling pathway participates in the differentiation of hepatic progenitor cells into bile duct epithelial cells and progression of hepatic fibrosis in cholestatic liver fibrosis rat

Objective: To investigate differentiation direction of hepatic progenitor cells (HPCs) in cholestatic liver fibrosis (CLF), and the role of Notch signaling pathway in the differentiation of HPCs. Methods: A CLF rat model was established by bile duct ligation (BDL) followed by monitoring changes of Notch signal pathway and the cellular origin of proliferating cholangiocytes. After intraperitoneal injection of DAPT (a Notch signaling inhibitor) after bile duct ligation, the progress of liver fibrosis and the proliferation of cholangiocytes after inhibition of the Notch pathway were analyzed. Results: Data showed that bile duct proliferation gradually increased along with inflammatory cell infiltration and proliferating bile duct cells surrounded by abundant collagen in the BDL group. Immunostaining confirmed markedly increased expression of CK19, OV6, Sox9 and EpCAM. In addition, RT-PCR results showed that Notch signaling pathway was activated significantly. Once the Notch signaling pathway was inhibited by DAPT, bile duct proliferation markedly suppressed along with significantly decreased the mRNA expression of CK19, OV6, Sox9 and EpCAM, compared with BDL group [(10.2±0.7) vs. (22.3±0.8), (7.6±1.5) vs. (18.1±3.7), (1.4±0.4) vs. (4.1±1.1), (1.3±0.3) vs. (5.0±1.4), respectively, P<0.01]. Moreover, liver fibrosis was also reduced significantly. Conclusion: Notch signaling activation is required for HPCs differentiation into cholangiocytes in CLF and inhibition of the Notch signaling pathway may offer a therapeutic option for treating CLF.

Notch Signaling Pathway Regulates Angiogenesis via Endothelial Cell in 3D Co-Culture Model.

This study aimed to investigate the role of Notch signaling pathway for angiogenesis in a three-dimensional (3D) collagen gel model with co-culture of adipose-derived stromal cells (ASCs) and endothelial cells (ECs). A 3D collagen gel model was established in vitro by implanting both ASCs from green fluorescent protein-labeled mouse and ECs from red fluorescent protein-labeled mouse, and the phenomena of angiogenesis with Notch signaling inducer Jagged1, inhibitor DAPT and PBS, respectively were observed by confocal laser scanning microscopy. Semi-quantitative PCR and immunofluorescent staining were conducted to detect expressions of angiogenesis-related genes and proteins. Angiogenesis in the co-culture gels was promoted by Jagged1 treatment while attenuated by DAPT treatment, compared to control group. In co-culture system of ASCs and ECs, the gene expressions of VEGFA, VEGFB, Notch1, Notch2, Hes1, Hey1, VEGFR1,and the protein expression of VEGFA, VEGFB, Notch1, Hes1, Hey1 were increased by Jagged1 treatment and decreased by DAPT treatment in ECs. And the result of VEGFR3 was the opposite. However, the same results did not appear completely in ASCs. These results revealed the VEGFA/B-Notch1/2-Hes1/Hey1- VEGFR1/3 signal axis played an important role in angiogenesis when ASCs and ECs were co-cultured in a 3D collagen gel model. J. Cell. Physiol. 232: 1548-1558, 2017. © 2016 Wiley Periodicals, Inc.

Redox Signaling and Myocardial Cell Death: Molecular Mechanisms and Drug Targets.

Cardiovascular diseases (CVD) are the major causes of mortality and morbidity in the world. Apoptotic cardiac cell death has been reported in myocardial tissues obtained from patients with congestive heart failure, myocardial infraction, arrhythmogenic right ventricular dysplasia, myocarditis, chemotherapy induced cardiomyopathies, diabetic cardiomyopathy, and so forth. Further, loss of functional capacity of the myocytes via apoptotic cell death accounts for the major cause of morbidity and mortality in the above-mentioned heart diseases. Thus prevention of cardiomyocyte cell death [preserving functional myocardium] could profoundly improve the clinical outcome of the treatment for the aforementioned CVD. Despite significant progress made with clinical management of CVD, development of specific inhibitors to thwart the cardiomyocyte apoptosis is currently restricted due to the limited knowledge underlying the signaling process involved in this process. In addition, the factors triggering and mediating the apoptotic cell death in the myocardium are also murky. Therefore, it is imperative to understand risk factors, regulators, and biomarkers for apoptotic cell death which could aid in the development of therapeutic strategies to mend the injured myocardium. Myocardial ischemia/reperfusion (I/R) injury is often encountered during various surgical interventions of CVD. Although the sterile inflammation plays a pivotal role in resolving the myocardial tissue injury, dysregulated inflammation process can alter the homeostasis process and perpetuate the tissue injury. Excessive generation of reactive oxygen species (ROS) due to mitochondrial dysfunction is thought to be the central player in myocardial injury. D. M. Muntean et al. have thoroughly reviewed the various sources of ROS arising from mitochondria and their physiological and pathological role during the myocardial ischemia/reperfusion (I/R) injury. Further, the authors also discussed the therapeutic strategies and mitochondria targeted antioxidants molecules being investigated in clinical trial targeting mitochondrial dysfunction associated with I/R injury. In a similar tone, G. A. Kurian et al. in their review article have discussed the central role of oxidative, reductive stress in the development of myocardial I/R injury, diabetic heart disease, and heart failure. Stroke accounts for the major cause of mortality among subjects with increased risk for CVD such as in patients with diabetes, hypertension, and dyslipidemia. In an effort to develop newer therapeutic agent for the management of stroke, H. Hu et al. used an active component isosteviol derived from Stevia rebaudiana leaf and demonstrated the cerebral-vascular protective property in a rodent model of stroke. Further, Z. Fan et al. demonstrated that isosteviol could modulate the sarcKATP and mitoKATP channels in isolated ventricular myocytes. J. Paloczi et al. demonstrated that nitric oxide donor protects the cardiomyocytes derived from human embryonic stem cells against ischemia induced apoptosis. Geriatric population is at increased risk of developing sepsis. F. Li et al. demonstrated the key role of translocation factor EB (TFEB) in regulating the lipopolysaccharide induced inflammation, oxidative stress, autophagy, and apoptosis in the aged heart and postulated TFEB as drug target to ameliorate the myocardial tissue injury in aged subjects. Several anticancer agents exhibit profound noxious effects on the heart and increase the mortality rates among cancer survivors. Therefore, myocardial toxicity imposed by these anticancer agents often restricts the clinical usage particularly among pediatric patients. In this direction, S. Ojha et al. have in depth reviewed the need for effective cardioprotective adjuvants that could circumvent the chemotherapeutic agent induced cardiotoxicity. Specific phytochemicals and their mechanistic actions in combating doxorubicin induced cardiotoxicity in various preclinical studies were discussed. Burn can inflict severe myocardial tissue injury. W. Cai et al. demonstrated the pivotal role of Notch signaling pathway in mitigating burn-induced myocardial tissue in a rodent model. The articles published in this special issue have addressed some of the contentious issues that pertain to redox signaling and myocardial cell death in CVD. We hope that these articles could stimulate our continuing efforts to understand the molecular and cellular pathophysiological mechanisms and impairments that culminate in the cardiomyocyte death in CVD. Mohanraj Rajesh Lu Cai Partha Mukhopadhyay Srinivasan Vedantham