Inhibitory Effect of Gamma-Secretase on the Survival Rate of Dental Pulp Stem Cells: An in Vitro Study

Objective: To evaluate in vitro the effect of gamma-secretase inhibition on the survival of dental pulp stem cells. Material and Methods: Sound teeth have been used. Dental pulp stem cells were isolated by enzymatic digestion. An appropriate number of cells were treated with different concentrations of gamma secretase enzyme (DAPT) (1, 3, 6.25, 12.5, 25.5, 37.5, 50 and 100 µM). The metabolic activity of cells and the distribution of cells in different phages of cell cycle was evaluated by MTT assay and flow cytometry, respectively. Statistical analysis was made one-way ANOVA. Comparison was made between the groups on the level of p<0.05. Results: In low concentration of DAPT (1, 3, 6.25, 12.5) the growth rate of the cells increases, whereas in high concentration of DAPT (25.5, 37.5, 50, 100) can significantly reduce the viability of the treated cells. The results also indicate that DAPT can interrupt the cell cycle in G1 phase. Conclusion: The DAPT for dose-dependent survival rate of dental pulp stem cells and affect cell population increase in the G1 phase of the cell cycle.

Effect of Notch-Hes1 signaling blockade by a γ-secretase inhibitor on the expression of γδT17 cells in a mouse model of psoriasis-like skin inflammation / 中华皮肤科杂志

Objective@#To evaluate the effect of Notch-Hes1 signaling blockade by a γ-secretase inhibitor on the expression of γδT17 cells in a mouse model of psoriasis-like skin inflammation.@*Methods@#Forty-five healthy specific pathogen-free (SPF) male BALB/c mice were randomly divided into control group, model group and intervention group by simple random sampling. The model group and intervention group were both topically treated with imiquimod 5% cream (62.5 mg once a day) on the shaved back, the intervention group were then intraperitoneally injected with the γ-secretase inhibitor DAPT (10 mg/kg once a day) immediately after topical application of imiquimod, and the control group were topically treated with equivalent amount of vaseline once a day. After 6-day treatment, psoriasis area and severity index (PASI) was used to evaluate changes of skin lesions. On day 7, blood samples were obtained from all the mice through heart puncture after anesthetization, and spleen and skin tissues were acquired to prepare single cell suspension. Spleen index was compared among the 3 groups. Skin tissues on the mouse back were resected and subjected to hematoxylin-eosin staining to observe histopathological changes. Flow cytometry was performed to determine the percentage of γδT17 cells in the spleen and skin tissues, real-time reverse transcription (RT) -PCR to measure the mRNA expression of Hes1 in single cell suspension of the spleen, and enzyme-linked immunosorbent assay (ELISA) to determine the serum level of interleukin (IL) -17A. Statistical analysis was carried out by using one-way analysis of variance and repeated measures analysis of variance for comparison of indices among groups, and Pearson correlation analysis for evaluating the correlation between different indices.@*Results@#Twenty-four hours after the final treatment, the intervention group showed milder psoriasis-like skin inflammation, lower PASI score, and milder degree of epidermal thickening and dermal inflammatory cell infiltration compared with the model group. The model group showed significantly increased spleen index (12.534 ± 1.636) , proportions of γδT17 cells in the spleen (24.659% ± 4.603%) and skin tissues (22.127% ± 5.670%) , mRNA expression of Hes1 in the spleen (4.867 ± 0.543) , and serum level of IL-17A ([22.478 ± 2.776] ng/L) compared with the control group (all P < 0.01) . However, the above indices were significantly lower in the intervention group (9.449 ± 1.040, 14.966% ± 5.770%, 13.631% ± 5.946%, 2.541 ± 0.347, [18.639 ± 1.816] ng/L) than in the model group (all P < 0.01) . In the model group and intervention group, there were positive correlations between the proportions of γδT17 cells in the spleen and serum levels of IL-17A (r = 0.56, 0.53 respectively, both P < 0.05) , between the proportions of γδT17 cells in skin lesions and PASI scores (r = 0.56, 0.52 respectively, both P < 0.05) , as well as between the mRNA expression of Hes1 in the spleen and the proportions of γδT17 cells (r = 0.61, 0.58 respectively, both P < 0.05) or serum levels of IL-17A (r = 0.60, 0.54 respectively, both P < 0.05) .@*Conclusion@#Notch-Hes1 signaling blockade by γ-secretase inhibitor can markedly inhibit the expression of γδT17 cells, and effectively alleviate the severity of psoriasis-like skin inflammation in mouse models.

γ-Secretase mutations in acne inversa / 中华皮肤科杂志

Acne inversa is a chronic inflammatory skin disease of the folliculo-sebaceous-apocrine unit. Currently, genetic and immunological factors are hot topics in the study of its pathogenesis. Genetic factors are mainly related to γ-secretase mutations, and abnormal expression of the γ-secretase-Notch axis leads to increased keratinization of hair follicles and inflammation in some patients with haploinsufficiency of the γ-secretase gene. Mutations in the γ-secretase gene are not necessary for acne inversa, and the risk of Alzheimer′s disease in familial acne inversa patients still remains unclear. Some progress has been made in researches on the association of genotype with phenotype in acne inversa patients, but further studies with large sample size are needed for verification.

Expression of DLL3 in small cell lung cancer and its application in targeted therapy / 国际肿瘤学杂志

Small cell lung cancer (SCLC) has a poor biological behavior,high probability of recurrence and metastasis,and limited treatment.The Notch signaling pathway is an evolutionarily conserved pathway that regulates the growth of many cell types through local cell-cell interactions.It controls the differentiation,proliferation and survival of cells.As a ligand for the Notch pathway,delta-like protein 3 (DLL3) is highly expressed on the membrane of SCLC cells.DLL3 plays an important role in cancer initiation and epithelial mesenchymal transition,invasion and metastasis of SCLC.Rovalpituzumab tesirine is a conjugate of directed against DLL3,which shows great potential for SCLC therapy.

γ-Secretase mutations in acne inversa / 中华皮肤科杂志

Acne inversa is a chronic inflammatory skin disease of the folliculo-sebaceous-apocrine unit.Currently,genetic and immunological factors are hot topics in the study of its pathogenesis.Genetic factors are mainly related to γ-secretase mutations,and abnormal expression of the γ-secretase-Notch axis leads to increased keratinization of hair follicles and inflammation in some patients with haploinsufficiency of the y-secretase gene.Mutations in the γ-secretase gene are not necessary for acne inversa,and the risk of Alzheimer's disease in familial acne inversa patients still remains unclear.Some progress has been made in researches on the association of genotype with phenotype in acne inversa patients,but further studies with large sample size are needed for verification.

Screening of microRNAs targeting Notch signaling pathway implicated in inner ear development and the role of microRNA-384-5p / 中华耳鼻咽喉头颈外科杂志

Objective@#To screen the key microRNAs targeting Notch signaling pathway in inner ear and investigate its potential regulating function.@*Methods@#The interaction network and the Core-Notch network, involved with key genes in Notch signal pathway and differential-expressed microRNAs in inner ear, were constructed by bioinformatics methods. The important microRNAs in regulating Notch signaling pathway were screened via topological and GO analysis, followed by in vivo and in vitro investigation.@*Results@#MiRNA-384-5p was identified as a key regulator specifically expressed in mouse brain and inner ear, which could down-regulate Notch1. The Notch1 expression was found significantly down-regulated in miRNA-384-5p-mimic-transfected HeLa cells. The dual-luciferase reporter gene assay further confirmed the effect of miRNA-384-5p on the down-regulation of Notch1 and Dll4 in Notch signaling pathway.@*Conclusions@#The Core-Notch network is constructed to screen microRNAs implicated in inner ear development, and miRNA-384-5p is screened and verified to be target-regulating the Notch signaling pathway, which could be the potential target in the regeneration of impaired hair cells.

Notch signaling pathway in lung cancer and lung cancer stem cells and its inhibitors / 国际肿瘤学杂志

Notch signaling pathway is involved in the abnormal differentiation and self-renewal of lung cancer stem cells.The further studies for the roles of Notch signaling pathway in the regulation of lung cancer stem cells are expected to find new targets in the diagnosis and treatment of lung cancer.Inhibitors of the Notch signaling pathway may be effective in the treatment of lung cancer.Lung cancer stem cells are thought to be a major cause of recurrence of lung cancer,therefore,targeted therapy for lung cancer stem cells may be more effective than treatment for the entire tumor.

Relationship between the Notch signaling pathway and the development and progression of liver fibrosis / 临床肝胆病杂志

The Notch signaling pathway mainly includes Notch receptors and ligands, transcription factors, and DNA binding proteins. It decides the way of cell proliferation, differentiation, and apoptosis. Recent studies have shown that the Notch signaling pathway plays an important role in the development and progression of liver fibrosis, and blocking or activating the Notch signaling pathway can influence the progression of liver fibrosis. This article reviews the research advances in the composition of the Notch signaling pathway, the mechanism by which it is activated, and its association with liver fibrosis.

Expression of Notch pathway receptors and ligands in cutaneous malignant melanoma / 中华皮肤科杂志

Objective To determine the expression of Notch pathway receptors (Notch1 and Notch4) and ligands (Jagged1 and Dll4) in cutaneous malignant melanoma (CMM) tissues,and to preliminarily explore the role of the Notch signaling pathway in the pathogenesis of CMM.Methods Immunohistochemical study was performed to determine the expression pattern and intensity of Notch1,Notch4,Jagged1 and Dll4 in 40 paraffin-embedded CMM specimens and 15 paraffin-embedded pigmented nevus specimens.Statistical analysis was carried out by chi-square test and Spearman rank correlation analysis with the SPSS 21.0 software.Results Notchl was detected in 31 (77.5％) of 40 CMM specimens,as well as in 3 of 15 pigmented nevus specimens,and the positive rates significantly differed between the two groups (x2 =15.281,P ＜ 0.001).However,no significant difference in the expression intensity of Notch1 was observed between 18 in situ melanoma tissues and 22 invasive melanoma tissues (x2 =0.631,P =0.427).In addition,the positive rates of Notch4,Jagged1 and Dll4 were also significantly higher in the CMM group than those in the pigmented nevus group (all P ＜ 0.05),and the expression intensity of Notch4,Jagged1 and Dll4 significantly differed between in situ and invasive melanoma tissues (all P ＜ 0.05).In CMM tissues,the expression of Notch1 was positively correlated with that of Jagged1 (rs =0.350,P =0.027) and Dll4 (rs =0.562,P ＜ 0.001),while the expression of Jaggedl was negatively correlated with that of Dl14 (rs =-0.734,P ＜ 0.001).Conclusion Abnormality of the Notch signaling pathway may be involved in the pathogenesis of melanoma,but further researches are still needed to elucidate the detailed mechanism.

Advances in cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy / 国际脑血管病杂志

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is the most common hereditary cerebral small vessel disease.NOTCH3 missense mutation causes its coded cysteine occurring odd change and then affects the conformation and function of protein of NOTCH3.The abnormal NOTCH3 protein has vascular smooth muscle toxicity and finally deposits in the cerebral small blood vessels and causes the disease.Usually,CADASIL can be suspected by its typical clinical manifestations and neuroimaging findings.Its diagnosis needs genetic testing or skin biopsy to find the outer granular osmiophilic deposits of small vascular smooth muscle cells or immunohistochemical NOTCH3-ECD staining positive.For nearly two decades,the studies on genetics,pathogenesis,clinical manifestations,and diagnostic techniques of CADASIL have made great progress,however,many important questions have not been fully clarified and have new discoveries,such as the NOTCH3 gene mutation pattern and loci,and the relationship between gene phenotype and clinical phenotype,optimization of diagnosis process,depth study of pathogenic mechanism,exploration of new discoveries,new therapeutic targets and concepts.This article reviews the genetic characteristics,pathogenesis,and clinical diagnosis and treatment technology of CADASIL.

R607C mutation of NOTCH3 gene and clinical features in 4 CADASIL families in Henan, China / 国际脑血管病杂志

Objective To investigate the NOTCH3 gene mutation and clinical features in cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) families.Methods The clinical features of 4 CADASIL probands in Henan,China were analyzed retrospectively,and the incidences of other members in their families were investigated.The NOTCH3 gene mutations in the 3rd,4th,llth,and 18th exons were detected and the results were analyzed in the patients and some family members.Results Gene sequencing showed that 6 patients in 4 families and 1 mutant carrier had NOTCH3 gene R607C mutation in exon llth,they all met the clinical features of CADASIL.Three patients accompanied with vascular risk factors.The clinical stroke patients had unilateral limb weakness.All 5 patients with complete head MRIdata had thalamic infarction.Conclusions In the 4 CADASIL families of R607C mutation,the clinical features of 6 patients with CADASIL were similar,but there were individual differences in different family members.Imaging examination has important role in the diagnosis of CADASIL.The vascular risk factors,such as hyperte.

Expression analysis of notsh signaling pathway molecules in shed cultured in keratinocyte growth medium

Aim: To detect the expression of molecules associated with Notch signaling pathway in stem cells from human exfoliated deciduous teeth (SHED) cultured in specific differentiation medium, namely, keratinocyte growth medium (KGM). Methods:RNA was extracted from SHED harvested on day 1, 3 and 7. RNA was reverse-transcribed to obtain the cDNA and then proceeded with PCR using specific primers for the Notch signaling pathway molecules (Notch1, Jagged-1, Jagged-2 and, Hes1) as well as stem cell marker (Nanog). PCR products were electrophoresed on a 2% agarose gel and stained with SYBR green. Results:Notch-1 was highly expressed in SHED cultured in KGM and showed increase in density as the days progressed, while Jagged-1 showed a decrease. Jagged-2 on the other hand, showed a slight increase on day 3 followed by a decrease on day 7. However, Hes-1 was not expressed in SHED cultured in KGM. Nanog showed expression only on day 3 and gradually increased in expression on day 7. Conclusions:Notch signaling pathway associated molecules; Notch-1, Jagged-1, Jagged-2, and stem cell marker Nanog are expressed in SHED cultured in KGM which may be involved in the differentiation into epithelial-like cells in human dental pulp tissues.

Neuroprotective effect of cerebral ischemic preconditioning is associated with regulation of expressions of nuclear factor-κB and Hes1 in rats / 国际脑血管病杂志

Objective To investigate the neuroprotective mechanism of cerebral ischemic preconditioning by detecting the expression changes of hippocampus nuclear factor-κB (NF-κB) and Hesl mRNA after cerebral ischemia-reperfusion in rats.Methods A total of 108 healthy male SD rats were randomly divided into a cerebral ischemia group,a cerebral ischemic preconditioning group,and a sham operation group,and then redivided into 22 h,48 h,72 h,7 d,and 14 d subgroups.Ischemic preconditioning was performed at day 3 before establishing the cerebral ischemia-reperfusion injury model by transient occlusion of right internal carotid artery for 10 min.At each time point after cerebral ischemia-reperfusion,the neurological deficit score and cerebral infarction volume measurement were performed,and the expressions of NF-κB and Hes1 mRNA in the hippocampus were detected by using real-time fluorescence quantitative polymerase chain reaction.Results The neurological function scores and the percentage of cerebral infarction volume in the cerebral ischemic preconditioning goup at each time point were significantly lower than those in the cerebral ischemia-reperfusion group (all P ＜0.05).The expression levels of NF-κB and Hesl mRNAs in each group had progressive reduction with time.Compared with the same time point,it showed that the expression levels of NF-κB and Hes1 mRNAs in the cerebral ischemic preconditioning group and the cerebral ischemia-reperfusion group were significantly higher than those in the sham operation group,the expression level of NF-κB mRNA in the cerebral ischemic preconditioning group was significantly lower than that in the cerebral ischemia-reperfusion group,and the expression level of Hesl mRNA was significantly higher than that in the cerebral ischemia-reperfusion group (all P ＜0.05).Conclusions The upregulation of Hesl and down-regulation of NF-κB may be involved in the neuroprotective mechanisms of cerebral ischemic preconditioning.

Effect of Dll4 at different concentrations on the biological functions of extravillous trophoblasts / 中国组织工程研究

BACKGROUND:Extravil ous trophoblasts exert a crucial effect on early pregnancy. When extravil ous trophoblasts function abnormal y, many pregnancy diseases can develop, such as preeclampsia, fetal growth restriction and placental implantation. OBJECTIVE:To investigate the effect of Dl 4, a ligand of Notch signaling family, on biological functions of extravil ous trophoblasts. METHODS:Human extravil ous trophoblast cel lines, HTR-8/SVneo, were cultured with human recombined protein Dl 4 of different concentrations (0, 0.125, 0.25, 0.5, 1.0 mg/L). Cel viability was tested by cel counting kit-8 assay. Transwel assay was applied to examine the changes in cel migration and invasion ability. RESULTS AND CONCLUSION:Dl 4 could significantly improve migration and invasion abilities of extravil ous trophoblasts, but had no effect on cel viability. In addition, Dl 4 regulated the invasion ability of extravil ous trophoblast in a dose-dependent manner. Above al , Dl 4 can play an important role in normal pregnancy by regulating the biological functions of extravil ous trophoblasts.

A Notch signaling pathway inhibitor affects chondrogenesis of human umbilical cord mesenchymal stem cells / 中国组织工程研究

BACKGROUND:Notch singling pathway is very important for cellproliferation and differentiation, but its role is stil unknown during chondrogenesis of human umbilical cord mesenchymal stem cells. OBJECTIVE:To investigate the effect of N-[N-(3,5-difluorophenacetyl-L-alanyl)]-(S)-phenylglycinet-butyl ester (DAPT) on inducing human umbilical cord mesenchymal stem celldifferentiation into chondrocytes. METHODS:Human umbilical cord mesenchymal stem cells were isolated from human umbilical cord, then were induced to differentiate into chondrocytes. There were four experimental groups:non-induced group, high-glucose Dulbecco’s modified Eagle’s medium containing 5%fetal bovine serum and 1%double antibody;induced group, induced medium containing 6.25 mg/L insulin, 6.25 mg/L transferrin, 10μg/L transforming growth factor beta 1, 0.1μmol/L dexamethasone, 50 mg/L vitamin C, 5%fetal bovine serum and 1%double antibody;dimethyl sulfoxide group, induced medium containing 0.1%dimethyl sulfoxide;DAPT group, induced medium containing 5μmol/L DAPT. RESULTS AND CONCLUSION:After chondrogenic induction, the morphology of human umbilical cord mesenchymal stem cells became polygon and positive for toluidine blue and immunofluorescence staining;the expression of Jag-1, PS-1, Notch-1 and Hes-1 decreased significantly (P<0.01). After the addition of DAPT, compared with the induced group, the relative gene expression of Jag-1, PS-1 and Hes-1 decreased markedly (P<0.01), the relative gene expression of Notch-1 decreased obviously as wel (P<0.05), and the contents of proteoglycan and col agen type II proteins decreased significantly (P<0.01). At the same time, the relative gene expression of proteoglycan decreased obviously (P<0.05), and the relative gene expression of col agen type II decreased in part. Notch signaling pathway exists in human umbilical cord mesenchymal stem cells, once chondrogenesis begins, the signaling strength wil decline rapidly. DAPT may prevent human umbilical cord mesenchymal stem cells from differentiating into chondrocytes by Jag-1-Notch-1-Hes-1 pathway.

Notch signaling pathway and glioma stem cell niche / 国际肿瘤学杂志

A small fraction of tumor stem cells exist in glioma and play a key role in the tumorigenesis and propagation of glioma.They have a close relationship with their niche that offers structural and functional support.In glioma niche,vascular endothelial cells can provide Notch ligands for cancer stem cells to activate Notch signaling pathway and contact with other signaling pathways,maintaining the tumor stem cell self-renewal and increasing resistance of brain tumor stem cells to radiotherapy.Therefore,Notch signaling pathway is considered to be a new therapeutic target of glioma.

Advances in research on Notch signaling pathway and digestive system tumors / 肿瘤

As a highly conserved genetic evolution of the interaction pathway between neighboring cells, Notch signaling plays an important role in normal cell growth, differentiation, proliferation, survival and apoptosis, and is also related to the development of many tumors. The expression of Notch-1 decreases in esophageal squamous cell carcinoma, while the result is contrary in esophageal adenocarcinoma. Besides, the expression of Notch signaling in a high level promotes the formation of gastric function, which predicts the risk of gastric cancer. Notch-1 expression in colon cancer is positively correlated with tumor grade, lymph node metastasis and poor overall survival of patients. Additionally, Notch ligand Dll-4 is capable of promoting colon cancer angiogenesis which contributes to distant metastasis and invasion of cancer cells. However, Notch-2 may inhibit the growth of colon cancer. In summary, although Notch signaling has mostly been associated with oncogenic and growth-promoting roles, it can also function as a tumor suppressor inducing cell differentiation and inhibiting proliferation of tumor cells, showing two diametrically opposite effects in development of cancer depending on tumor type. Applying γ-secretase inhibitors, small interfering RNAs and monoclonal antibodies to blocking Notch signaling pathway will be a new direction for the therapy of tumors. Copyright© 2012 by TUMOR.

Research progress on relationship between Notch signaling and hematological disorders / 白血病·淋巴瘤

Notch signaling can control T cell development and differentiation and lead to acute T cell lymphoma/leukemia (T-ALL). Most Notch1mutations in human T-ALL are the HD domain and the PEST domain. Aberrant Notch1activation can induce T-ALL by PI3K/Akt, mTOR or/and NF-κB pathways. Some recent reports suggested that Notch signaling could not only control T cell development,but also has a role in acute myeloid leukemia (AML) and Graft-versus-host Disease (GVHD) after allogeneic hematopoietic stem cell transplantation (allo-HSCT).Moreover,Notch signaling can regulate the expansion of HSC as well as generate increased numbers of progenitor cells which are capable of rapid repopulation to improve HSC homeostasis and hematopoietic recovery after allo-HSCT.

Trichostatin A induces apoptosis and alteration of Notch pathway in human pancreatic cancer cell line PANC-1 / 中华普通外科杂志

Objective To investigate the efficiency of Trichostatin A (TSA) in inducing cell apoptosis and altering the Notch pathway genes expression in PANC-1 cells line.Methods The survival rate and apoptosis of PANC-1 cells were measured by MTT assay and Hoechst 33258 staining,respectively.mRNA expression levels of the genes,numb,gcn512,dll3,hes6,eaf2,cytohesins,in PANC-1 cells were assessed by real-time quantitive PCR.Western blot was used to measure the expression of bcl-2,bax,actived caspase-3 and NICD protein which was the biologically active form of Notch-1.Results After culturing with 0.1,0.2,and 0.4 μmol/L TSA for 24 hours,the cellular survival rate of PANC-1 cells significantly decreased to 72％,58％ and 39％,respectively.The survival rate of PANC-1 was negatively correlated to time length of culture with TSA.Increased apoptosis of PANC-1 cells after 12,24 and 36 h culture with TSA was detected by Hoechst 33258 staining.Western blotting showed that the expression of bax,actived caspase-3 and NICD protein increased while the bcl-2 protein decreased after culture with TSA.In real time quantitive PCR assessment,the mRNA expression of numb and hes6 in PANC-1 cells were upregulated by TSA (P ＜ 0.05),while the mRNA expression of gcn512 and dll3 were down-regulated by TSA (P ＜ 0.05).While mRNA expressions of eaf2 and cytohesin1,2,3,4 were not affected by TSA.Conclusions TSA induces apoptosis of pancreatic cancer cell line PANC-1.The Notch signal pathway may be involved in inducing cellular apoptosis of PANC-1 when cultured with TSA.

Notch3 signaling pathway and cerebrovascular diseases / 国际脑血管病杂志

The Notch pathway is an evolutionarily conserved signal transduction pathway. It consists of a complex system of interaction. Its function is associated with the embryonic development and cell differentiation regulation. Studies in recent years have demonstrated that Notch pathway is associated with specific human diseases, in which Notch3 signaling pathway is closely associated with the nervous system development and the structural integrity of blood vessels. Notch3 mutation may cause cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy.