Cochlea cell-specific marker expression upon in vitro Hes1 knockdown

NOTCH pathway proteins, including the transcriptional factor HES1, play crucial roles in the development of the inner ear by means of the lateral inhibition mechanism, in which supporting cells have their phenotype preserved while they are prevented from becoming hair cells. Genetic manipulation of this pathway has been demonstrated to increase hair cell number. The present study aimed to investigate gene expression effects in hair cells and supporting cells after Hes1-shRNA lentivirus transduction in organotypic cultures of the organ of Corti from postnatal-day-3 mice. Forty-eight hours after in vitro knockdown, Hes1 gene expression was reduced at both mRNA and protein levels. Myo7a (hair cell marker) and Sox2 (progenitor cell marker) mRNA levels also significantly increased. The modulation of gene expression in the organ of Corti upon Hes1 knockdown is consistent with cell phenotypes related to lateral inhibition mechanism interference in the inner ear. The lentivirus-based expression of Hes1-shRNA is a valuable strategy for genetic interference in the organ of Corti and for future evaluation of its efficacy in protocols aiming at the regeneration of hair cells in vivo.

Effect of traditional Chinese medicine for replenishing qi, nourishing yin and activating blood on renal Notch/Hes1 signaling in rats with diabetic nephropathy / 南方医科大学学报

OBJECTIVE@#To observe the effects of a traditional Chinese medicine (TCM) capsule for replenishing qi, nourishing yin and activating blood on Notch/Hes1 signaling pathway in the renal tissue and vascular endothelial CD34 and CD144 expressions in a rat model of diabetic nephropathy.@*METHODS@#Rat models of early-stage diabetic nephropathy were established by left nephrectomy and high- fat and high- sugar feeding combined with intraperitoneal injection of STZ. The rats were randomized into model group, benazepril group, and high-, moderate-, and low-dose TCM capsule groups for corresponding treatments, with 6 normal rats as the control group. After 8 weeks of drug treatment, blood glucose and 24-h urinary albumin of the rats were measured, and the renal histopathology was observed with HE staining; Hes1 expression in the renal tissue was detected with immunohistochemical staining, and the renal expressions of CD34 and CD144 were detected using Western blotting.@*RESULTS@#Compared with the normal control group, the rat models of diabetic nephropathy showed obvious abnormalities in 24- h urinary albumin and expressions of Hes1, CD34 and CD144d. The TCM capsule at both the high and moderate doses significantly reduced 24-h urinary albumin in the rats; the renal expressions of Hes1 and CD34 was significantly reduced in all the dose groups, and the expression of CD144 was significantly reduced in the high- dose group. Compared with benazepril group, the TCM capsule obviously reduced CD34 expression at all the 3 doses and lowered CD144 expression at the low dose. Histopathologically, the rats in the model group showed glomerular hypertrophy, increased mesenteric matrix, thickening and widening of the mesenteric membrane, and nodular hyperplasia. These pathologies were obviously alleviated by treatment with the TCM capsule at the high and moderate doses.@*CONCLUSIONS@#The Traditional Chinese medicine (TCM) capsule for replenishing qi, nourishing yin and activating blood can reduce Hes1, CD34 and CD144 in kidney tissue of model rats, play a protective role on kidney function and delay the development of DN.

Expression Levels of JARID1B, Hes1 and MMP-9 Genes in CML Patients Treated with Imatinib Mesylate / 中国实验血液学杂志

OBJECTIVE@#To explore the relationship between the expression levels of JARID1B,Hes1 and MMP-9 genes and the stages of chronic myelogenous leukemia(CML) and the curative effect of imatinib mesylate (IM).@*METHODS@#Peripheral blood samples of 15 cases of CML in chronic phase and 10 cases of CML in progressive phase were collected from the Hematology Department of Taihe Hospital affiliated to Hubei University of Medicine and 15 cases of healthy people in the Physical Examination Center. CML patients were divided into effective group and ineffective group based on the efficacy after treatment with IM, then real-time PCR was used to detect the expression levels of JARID1B, Hes1 and MMP-9 mRNA, finally, the differences in the level of gene expression and their correlations with CML stages and IM curative efficacy were analysed.@*RESULTS@#The expression levels of Hes1 and MMP-9 in initially diagnosed patients in chronic and progressive phase without IM treatment were significantly higher than those of health people（P＜0.05）. There was no significant difference in the expression level of JARID1B between chronic phase patients and health people（P＞0.05）, but the expression level of JARID1B in the progressive phase patients was higher than that of health people （P＜0.05）. The expression levels of JARID1B and Hes1 in the IM-effective group were not significantly different from those in the IM-ineffective group (P=0.85,P=0.82）, while the expression level of MMP-9 in the IM-effective group [JP2]was significantly lower than that in the IM-ineffective group（P＜0.05）.@*CONCLUSION@#The expression levels of JARID1B Hes1 and MMP-9 relate with the different phase of CML; The expression levels of JARID1B and Hes1 have not significant relationship with IM curative efficacy, the MMP-9 gene expression level relates with IM curative efficacy.

Expression Levels of HES1, C-MYC and NF-kB in Peripheral Blood of Patients with T Cell Acute Lymphoblastic Leukemia and Their Significance / 中国实验血液学杂志

OBJECTIVE@#To analyze and investigate the expression levels of HES1, C-MYC and NF-kB in peripheral blood of patients with T cell acute lymphoblastic leukemia (T-ALL) and their significance.@*METHODS@#Sixty patients with T-ALL and 60 patients with acute myelogenous leukemia (AML) diagnosed in our hospital from June 2012 to March 2015 were enrolled in T-ALL group and AML group, respectively. Another 30 healthy people were enrolled in the control group. Peripheral blood was collected to detect the expression levels of HES1, C-MYC and NF-kB by RT-PCR. The general data and the expression of HES1, C-MYC and NF-kB in peripheral blood were compared among the patients with different type of leukemia, cytogenetical types and different prognosis.@*RESULTS@#There was no significant difference in baseline data, such as age and sex among the 3 groups (P＞0.05). The Hb level, WBC and Plt count, BM blast cell ratio in T-ALL and AML groups all were significantly higher than those in control group (P＜0.01), but there were no statistical difference in above-mentioned indicators between T-ALL and AML groups (P＞0.05). The expression levels of HES1, C-MYC and NF-kB in peripheral blood among 3 groups were significantly differenct (P＜0.01), the expressions levels of HES1, C-MYC and NF-kB in T-ALL and AML groups were significantly higher than those in control were significantly group (P＜0.01), moreover, the expression levels of above-mentional indicators in T-ALL groups were significantly higher than than those in AML group (P＜0.01). The expression levels of HES1, C-MYC and NF-kB iin T-ALL patients with poor prognosis were significantly higher than those in T-ALL patients with favorable prognosis (P＜0.01); the expression levels of HES1, C-MYC and NF-kB in peripheral blood of patients with different theraptic efficacy were follow: complete remission group＜partial remission group＜no remission group (P＜0.01).@*CONCLUSION@#The HES1, C-MYC and NF-kB are highly expressed in peripheral blood of the patients with T-ALL, moreover, the expression levels maybe different, because of the cytogenetic, and theraptic efficacy.

Inhibitory effects of Hes1 on acute myeloid leukemia cells / 中华血液学杂志

<p><b>OBJECTIVE</b>To elucidate the impact of Hes1 on the proliferation and apoptosis of acute myeloid leukemia (AML) cells.</p><p><b>METHODS</b>The expression levels of Hes1 and p21 in AML patient samples and myeloid leukemia cell lines were analyzed by real-time PCR. Hes1 was up-regulated by retrovirus transfection in AML cell lines and the proliferation capacity were assayed by MTT, cell cycle by Hoechst/PY, apoptosis by AnnexinV.</p><p><b>RESULTS</b>The expression of Hes1 in primary AML cells and HL-60, U937, KG1a cell lines were 0.67 ± 0.24, 0.59 ± 0.43, 0.42 ± 0.03, and 0.32 ± 0.26, respectively, and p21 were 0.54 ± 0.01, 0.44 ± 0.12, 0.36 ± 0.12, and 0.59 ± 0.43, respectively. Hes1 expression levels after transduction in HL-60, U937, KG1a were 4.9 ± 0.2, 5.2 ± 0.4, 5.8 ± 0.5, respectively. Induced activation of Hes1 led to AML cells growth arrest and apoptosis, which was associated with an enhanced p21 expression. Besides, activated Hes1 led to AML cells growth inhibition in vivo.</p><p><b>CONCLUSION</b>Hes1 could mediate growth arrest and apoptosis in AML cells, which may be a novel target for AML.</p>

Relationship between Hes-1 and airway inflammation and remodeling in a rat model of asthma / 中国当代儿科杂志

<p><b>OBJECTIVE</b>To study the changes of Hes-1, the target gene of Notch signaling pathway, and its relationship with airway inflammation and remodeling in a rat model of asthma.</p><p><b>METHODS</b>Forty-eight rats were randomly divided into an asthma group and a control group. The rats in the asthma group were sensitized and challenged by ovalbumin (OVA), and normal saline was used in the control group. Two groups were further divided into 3 subgroups according to time points after challenging, i.e. 4 weeks, 8 weeks and 12 weeks (n=8 rats each). Pathological changes of lungs were observed by light microscopy and the thickness of bronchial smooth muscle layer (Wam) was measured. The levels of IL-4 and INF-γ in rat serum and bronchoalveolar lavage fluids (BALF) were measured using ELISA. Expression levels of Hes-1 protein and mRNA were determined by immunohistochemistry and quantitative real-time PCR respectively.</p><p><b>RESULTS</b>Together with the extension of challenging, the Wam of rats in the asthma group increased, a decrease of INF-γ level and an increase of IL-4 level in serum and BALF were also observed, and the differences were statistically significant compared with those in the corresponding control group (P<0.05). Hes-1 protein and mRNA levels also increased gradually after OVA challenging and were higher than those in the control group (P<0.05). The levels of Hes-1 protein and mRNA were positively correlated with Wam and IL-4 in serum and BALF, but were inversely correlated with INF-γ in serum and BALF (P<0.05).</p><p><b>CONCLUSIONS</b>Levels of Hes-1 protein and mRNA increased, which were closely related with the levels of airway inflammatory factors and remodeling of airway smooth muscle. Hes-1 may play an important role in the pathogenesis of asthma.</p>

Effect of spinal cord extracts after spinal cord injury on proliferation of rat embryonic neural stem cells and Notch signal pathway in vitro

OBJECTIVE@#To investigate the effect of the spinal cord extracts (SCE) after spinal cord injuries (SCIs) on the proliferation of rat embryonic neural stem cells (NSCs) and the expressions of mRNA of Notch1 as well as of Hes1 in this process in vitro.@*METHODS@#The experiment was conducted in 4 different mediums: NSCs+PBS (Group A-blank control group), NSCs+SCE with healthy SD rats (Group B-normal control group), NSCs+SCE with SD rats receiving sham-operation treatment (Group C-sham-operation group) and NSCs+ SCE with SCIs rats (Group D-paraplegic group). Proliferative abilities of 4 different groups were analyzed by MTT chromatometry after co-culture for 1, 2, 3, 4 and 5 d, respectively. The expressions of Notch1 and Hes1 mRNA were also detected with RT-PCR after co-culture for 24 and 48 h, respectively.@*RESULTS@#After co-culture for 1, 2, 3, 4 and 5 d respectively, the MTT values of group D were significantly higher than those of group A, group B and group C (P0.05). Both the expressions of Notch1 and Hes1 mRNA of group D were significantly higher than those of other 3 groups after co-culture for 24 h and 48 h as well (P0.05). There was no difference in expressions of Notch1 and Hes1 mRNA between 24 h and 48 h treatment in group D.@*CONCLUSIONS@#SCE could promote the proliferation of NSCs. It is demonstrated that the microenvironment of SCI may promote the proliferation of NSCs. Besides, SCE could increase the expression of Notch1 and Hes1 mRNA of NSC. It can be concluded that the Notch signaling pathway activation is one of the mechanisms that locally injured microenvironment contributes to the proliferation of ENSC after SCIs. This process may be performed by up-regulating the expressions of Notch1 and Hes1 gene.

Effect of fermented cordyceps powder and prednisone on the Notch2/Hes-1 signaling activation in the kidney tubules of rats with acute aristolochic acid nephropathy / 中国中西医结合杂志

<p><b>OBJECTIVE</b>To investigate the effect of both fermented Cordyceps powder (CS) and prednisone on the Notch2/hes-1 signaling activation in the kidney tubules of rats with acute aristolochic acid nephropathy (AAAN).</p><p><b>METHODS</b>Totally 50 SD rats were randomly divided into 4 groups, i.e., the normal group, the model group, the CS group, the prednisone group, and the CS plus prednisone group, 10 in each group. The AAAN rat model was induced by intragastric administration of pure aristolochic acid A at the daily dose of 100 mg/kg for 3 days. Rats in the CS group were administered with CS at the daily dose of 5.0 g/kg by gastrogavage, while those in the prednisone group were administered with prednisone at the daily dose of 0.5 mg/kg. Rats in the CS plus prednisone group were treated by CS and prednisone. All treatment lasted for 3 successive weeks. Kidney functions [urea nitrogen (BUN) and serum creatinine (SCr)] were detected. The pathological changes of kidneys were observed by Hematoxylin-Eosin staining. The apoptosis of the renal tubular epithelial cells was detected by TUNEL. The protein expressions of Notch2 and Hes-1 in the renal tissue were detected by immunohistochemical assay and Western blot.</p><p><b>RESULTS</b>Results of HE staining showed the structure in the nephridial tissue was regular in rats of the normal group. The renal tubular necrosis occurred in the rats of the model group. The pathological changes of kidneys were obviously improved in the CS group, the prednisone group, and the CS plus prednisone group. Compared with the normal group, levels of BUN and SCr, semi-quantitative score of the tubular interstitial tissue, ratio of apoptotic cells, and expressions of Notch2 and Hes-1 proteins significantly increased in the model group (P < 0.01). Compared with the model group, the aforesaid indices significantly decreased in the 3 treatment groups (P < 0.01). All indices decreased most obviously in the CS plus prednisone group (P < 0.05, P < 0. 01).</p><p><b>CONCLUSIONS</b>Notch2/hes-1 signaling activation might be associated with apoptosis of renal tubular epithelial cells. Both CS and prednisone could play a nephroprotective role for AAAN. But CS plus prednisone could achieve the best effect. Inhabiting the Notch2/hes-1 signaling activation could be its nephroprotective mechanism.</p>

Effect of Notch1 signaling pathway activation on pancreatic cancer cell proliferation in vitro / 南方医科大学学报

<p><b>OBJECTIVE</b>To observe the effect of activation of Notch1 signaling pathway by Notch intracellular domain (NICD) plasmid transfection on pancreatic cancer cell proliferation and explore the underlying mechanism.</p><p><b>METHODS</b>The transfection rates were observed under microscope with fluorescence stimulation, and mRNA expression levels of Hes1 were detected by real-time PCR. Cell proliferation changes were evaluated by CCK-8 after NICD and control plasmid transfection in pancreatic cancer cells. Caspase 3 activity was examined using a caspase 3 detection kit.</p><p><b>RESULTS</b>The transfection rates of NICD plasmid were up to 80% by fluorescence stimulation observation. Hes1 expression was significantly increased after NICD plasmid transfection, suggesting the activation of Notch1 signaling pathway. NICD plasmid transfection significantly promoted cancer cell proliferation compared to control plasmid transfeciton. The activities of caspase 3 were obviously decreased after NICD plasmid transfection in 3 pancreatic cancer cell lines.</p><p><b>CONCLUSION</b>Activation of Notch1 signaling pathway by NICD plasmid transfection can promote the proliferation of pancreatic cancer cells by inhibiting the apoptosis pathway.</p>

Effect of DAPT on proliferation and apoptosis of human multiple myeloma cell line RPMI8226 / 中国实验血液学杂志

The aim of this study was to explore the effect of DAPT (N-[N-(3,5-difluorophenacetyl)-L-alanyl]-S-phenylglycinet-butyl ester) on proliferation in vitro of human multiple myeloma cell line RPMI8226 and its underlying mechanism. The proliferation of RPMI8226 cells was detected by CCK-8 method; flow cytometry was employed to assay the cell apoptosis rate;the expressions of Notch1 and Hes1 proteins were detected by Western blot. The results indicated that the proliferation of human RPMI8226 cells significantly decreased after treatment with DAPT 0.5 - 5.0 µmol/L for 24 - 72 h (P < 0.05) in a concentration- and time-dependent manner. DAPT significantly induced apoptosis of RPMI8226 cells (P < 0.05). The expressions of Notch1 and Hes1 proteins were gradually downregulated with the increase of DAPT concentration. It is concluded that the DAPT can inhibit the proliferation of RPMI8226 cells, which may be related with the down-regulation of the protein expression of Notchl and Hes1.

Effect of DLL4 siRNA on proliferation, migration and tube formation of choroid-retinal endothelial cells under hypoxic conditions / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Delta-like 4 (DLL4) is an endothelium specific Notch ligand and has been shown to function as a regulating factor during physiological and pathological angiogenesis. It has been reported that the DLL4-Notch signaling pathway is regulated by hypoxia and may prevent excessive angiogenesis through the inhibition of angiogenic branching and by triggering vessel maturation. Choroidal neovascularization (CNV) is a pathological form of angiogenesis in which hypoxia is thought to play an important role. This study was aimed to evaluate the role of DLL4 in the development of CNV.</p><p><b>METHODS</b>We utilized chemical hypoxia induced by 200 µmol/L CoCl2 to observe the expression of DLL4 in choroid-retinal endothelial cells (RF/6A cells), which are the primary cells involved in CNV. After transfection of a DLL4 small interfering RNA (siRNA), mRNA and protein expression of DLL4 and key downstream genes, including HES1 and HEY1, in hypoxic RF/6A cells were investigated by RT-PCR, real-time PCR, and Western blotting analysis. Three controls were used: one without transfection, one with transfection reagent, and one with scrambled negative control siRNA. The effects of the DLL4 siRNA on the biological function of hypoxic RF/6A cells during angiogenesis, including cell proliferation, migration and tube formation, were investigated.</p><p><b>RESULTS</b>The results showed that hypoxic conditions led to upregulation of DLL4 expression in RF/6A cells in vitro. After transfection, siRNA-duplex1 targeting DLL4 depleted the DLL4 mRNA levels by as much as 91.4% compared with the scrambled siRNA control, and DLL4 protein expression was similarly effected. There was no significant difference in DLL4 expression among the blank control, transfection reagent control, and scrambled siRNA groups. In addition, after transfection of hypoxic RF/6A cells with the DLL4 siRNA-duplex1, the mRNA levels of HES1 and HEY1, which function downstream of DLL4-Notch signaling, were lowered by 75.1% and 86.3%, respectively, compared with the scrambled siRNA control. Furthermore, knockdown of DLL4 expression significantly promoted the proliferation of hypoxic RF/6A cells and led to their arrest in the S phase of the cell cycle. Migration and tube formation of hypoxic RF/6A cells were significantly induced by the DLL4 siRNA, with the number of migrated cells increased by 1.6-fold and total tube length increased by 82.3%, compared with the scrambled siRNA (P < 0.05).</p><p><b>CONCLUSIONS</b>DLL4 functions as a negative regulator of angiogenic branching and sprouting. Based on our results, DLL4 signaling appears to play an essential role in the biological behavior of choroid vascular endothelial cells under hypoxia. Therefore, DLL4 may represent a novel target for CNV therapy in the future.</p>

Inhibitory effect and mechanism of (-)-epigallocatechin-3-gallate on HT29 and HCT-8 colorectal cancer cell lines and expression of HES1 and JAG1 / 中华胃肠外科杂志

<p><b>OBJECTIVE</b>To study the inhibitory effect of (-)-epigallocatechin-3-gallate (EGCG) on cancer cells line HCT-8 and HT29 and its influence on the expression of HES1 and JAG1.</p><p><b>METHODS</b>Colorectal cancer cells line HCT-8 and HT29 were cultured in vitro and treated with different concentrations of EGCG(10 mg/L, 20 mg/L, 35 mg/L). The inhibition of proliferation was tested by MTT analysis. Influence of EGCG on the cell apoptosis and cell cycle of HCT-8 and HT29 were detected with flow cytometry, and gene expression of HCT-8 and HT29 after EGCG treatment with real-time polymerase chain reaction.</p><p><b>RESULTS</b>EGCG affected the proliferation and apoptosis of HCT-8 and HT29. The inhibition rates of the three different concentrations of EGCG were(28.894±5.076)%, (34.903±1.794)%, and (39.028±0.105)% on HCT-8, and (14.682±4.244)%, (22.429±3.847)%, and (29.840±5.076)% on HT29. EGCG caused G(2)/M phase arrest and M phase transition in HCT-8 cell line, and S phase arrest and G2 phase transition in HT29 cell line. EGCG down-regulated HES1 gene expression in both cell lines, however, the differences were not statistically significant(both P>0.05). EGCG upregulated JAG1 gene expression in both cell lines, however only the difference in HCT-8 was statistically significant(0.201±0.018 vs. 0.440±0.077, P=0.029).</p><p><b>CONCLUSIONS</b>EGCG can significantly inhibit the proliferation of HT29 cells and HCT-8 cells by changing cell cycle and inducing cell apoptosis. The mechanism may be related to the upregulation of JAG1 gene expression.</p>

Regulation and mechanism of Notch signaling pathway in small cell lung cancer / 中华病理学杂志

<p><b>OBJECTIVE</b>To investigate the status of Notch signaling pathway in small cell lung cancer (SCLC).</p><p><b>METHODS</b>Expression plasmids of pEFBOS-NIC-MYC and pEFBOS-neo were transfected into NCI-H446 cells. Stably transfected cell lines were selected and their growth rates were examined by MTT method. Expression of downstream genes along the Notch signaling pathway were studied by RT-PCR. Protein expression of euroendocrine markers of CgA and NSE were detected by Western blot analysis and immunocytochemistry.</p><p><b>RESULTS</b>The expression of HES1 was increased in the pEFBOS-NIC-MYC group, but the expression of hASH in the pEFBOS-NIC-MYC group was decreased significantly. The transfected cells with pEFBOS-NIC-MYC plasmid showed a significantly slower growth rate compared with that of two control groups (P < 0.05, Student's t-test). Immunocytochemistry of NSE showed that PUs in the NIC transfected group, sham group and negative control group were 7.21 ± 0.59, 28.25 ± 1.46, 30.57 ± 1.31 respectively, the former one was smaller than the values of the latter two significantly (P < 0.01). Western blot analysis showed the grave scales of CgA in NIC transfected group and sham group to be 0.54 ± 0.03 and 0.99 ± 0.05 respectively (grave scales of the negative control was set as 1.00), the former one significantly smaller than that of the other two groups (P < 0.01). The grave scales of NSE in the NIC transfected group and sham group were 0.43 ± 0.02 and 1.07 ± 0.09 respectively (grave scales of the negative control was set as 1.00) and the former one was significantly smaller than the other two groups (P < 0.01).</p><p><b>CONCLUSION</b>Notch signaling pathway regulates SCLC cells through its inhibitory effect on hASH1 transcription via HES1 along with an expression inhibition of neuroendocrine markers in SCLC.</p>

DAPT enhances the apoptosis of human tongue carcinoma cells / 国际口腔科学杂志·英文版

<p><b>AIM</b>To investigate the effect of DAPT (gamma-secretase inhibitor) on the growth of human tongue carcinoma cells and to determine the molecular mechanism to enable the potential application of DAPT to the treatment of tongue carcinoma.</p><p><b>METHODOLOGY</b>Human tongue carcinoma Tca8113 cells were cultured with DAPT. Cell growth was determined using Indigotic Reduction method. The cell cycle and apoptosis were analyzed by flow cytometry. Real-time PCR and Immuno-Fluorescence (IF) were employed to determine the intracellular expression levels.</p><p><b>RESULTS</b>DAPT inhibited the growth of human tongue carcinoma Tca8113 cells by inducing G0-G1 cell cycle arrest and apoptosis. The mRNA levels of Hairy/Enhancer of Split-1 (Hes-1), a target of Notch activation, were reduced by DAPT in a dose-dependent manner. Coincident with this observation, DAPT induced a dose-dependent promotion of constitutive Caspase-3 in Tca8113 cells.</p><p><b>CONCLUSION</b>DAPT may have a therapeutic value for human tongue carcinoma. Moreover, the effects of DAPT in tumor inhibition may arise partly via the modulation of Notch-1 and Caspase-3.</p>

Role of Notch signaling in differentiation of retinal progenitor cells / 中南大学学报(医学版)

OBJECTIVE@#To investigate the role of Notch signaling in differentiation of Sprague-Dawley (SD) rat retinal progenitor cells (RPCs).@*METHODS@#RPCs were isolated from 16-day embryonic SD rats and cultured in suspension. RPCs were cultured respectively in media with (treatment group) or without (control group) gamma-secretase inhibitor X which was used to block Notch signaling. Morphological observation and immunocytochemistry were applied at day 14 to determine the cell types and analyze the expression of Notch pathway genes in both groups.@*RESULTS@#Most RPCs expressed Notch1 intracellular domains or its downstream transcriptional factor Hes1. A few expressed bHLH transcriptional factors NeuroD and Mash1. Most auto-differentiated RPCs expressed NeuroD or Mash1, while a few of them expressed Notch1 intracellular domains or Hes1. In the group treated with gamma-secretase inhibitor X, the positive rate of Nestin or GFAP was much lower than that in the control group while the positive rate of beta-tubulin was much higher than that in the control group. The difference in the positive rate of recovering between the two groups was not significant.@*CONCLUSION@#In vitro Notch signaling may inhibit retinal stem cells differentiation. Inhibiting Notch signaling in vitro may promote differentiation to neurons and partially inhibit glial differentiation.

Expression changes of Notch-related genes during the differentiation of human mesenchymal stem cells into neurons / 生理学报

The Notch signaling pathway has been implicated in the regulation of cell-fate decisions such as differentiation of embryo stem cells and neural stem cells into neurons. We cultured human mesenchymal stem cells (hMSCs) in vitro and induced hMSCs to differentiate into neural cells by beta-mercaptoethanol (beta-ME), DMSO and 3-tert-butyl-4-hydroxyanisole (BHA). Immunocytochemistry was utilized to detect neuron-specific enolase (NSE) and Nissl body, and flow cytometry was used to determine cell growth phases. The expressions of signal molecules involved in the Notch pathway such as Notch1, Jagged 1 (JAG1), presenilin 1 (PS1) and hairy and enhancer of split 1(HES1) were observed by RT-PCR and immunofluorescent techniques. The results were as follows: (1) Before induction, the percentage of hMSCs at G(0)/G(1) was 58.5%, and the percentage at S+G(2)/M was 41.5%. After induction, the percentage of hMSCs at G(0)/G(1) increased to 73.1%, 76.2% and 78.1%, respectively on days 2, 4 and 6, and the percentage at S+G(2)/M decreased to 26.8%, 24.8% and 21.9%, respectively; The percentage of NSE-positive cells reached (77+/-0.35) %; Nisslos staining was positive in cytoplasm. (2) Notch1 and JAG1 were both expressed in hMSCs before and after induction, but the mRNA expressions of both Notch1 and JAG1, detected by RT-PCR, decreased obviously after induction(P<0.05). Notch1 mRNA/beta-actin was 1.157, 0.815, 0.756 and 0.570, and JAG1 mRNA/beta-actin was 0.437, 0.350, 0.314 and 0.362, respectively, on days 0, 2, 4 and 6 after induction. The Notch pathway activation participant PS1 mRNA and Notch pathway target gene HES1 mRNA also decreased apparently after induction (P<0.05), and their mRNA/beta-actin was 0.990, 0.449, 0.441, 0.454 and 0.370, 0.256, 0.266, 0.240 on days 0, 2, 4 and 6, respectively. These observations indicate that the expressions of Notch signal molecules were suppressed when hMSCs were induced to differentiate into neural cells. Based on these findings, we propose that low level of Notch signaling activation may contribute to neural cell differentiation.

Expression of three kinds of transcription factors in greater epithelial ridge cells of rat cochlear / 中华耳鼻咽喉头颈外科杂志

<p><b>OBJECTIVE</b>To detect the expression of Math1, Hes1 and Hes5 in greater epithelial ridge (GER) cells of rat cochlear and explore their influence on hair cell differentiation.</p><p><b>METHODS</b>Postnatal day 0 (P0), day 1 (P1) , day 3 (P3) day 4 (P4) and day 5 (P5) rat cochlear were dissected respectively and then pure GER cells were separated by a combinatorial approach of attachment and mechanical separation. The total RNA of GER cells was extracted by Trizol one step method and the expression of Math1, Hes1 and Hes5 in GER cells was detected with reverse transcription polymerase chain reaction.</p><p><b>RESULTS</b>Math1 was expressed in P0 - P5 rat GER cells and Hes1 was expressed only in PO - P3 rat GER cells, while there was no expression of Hes5 in P0 - P5 rat GER cells.</p><p><b>CONCLUSIONS</b>Probably only when the expression of Math1 reaches a certain level can it induce GER cells to differentiate into hair cells. Meanwhile this process might controlled by Hes1 to some extent.</p>