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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.
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Objective To study the expression of Notch 1,Jagged1 and Notch intracellular domain (NICD) in epithelial ovarian carcinoma tissues and analyze the clinical significance.To explore the activity of γ-secretase in epithelial ovarian carcinoma cell line SKOV3 and the effect of N-[N-(3,5-dil uorophenacetyl)-L-alanyl]-S-phenylglycine t-butyl ester (DAPT),a γ-secretase inhibitor on the activity of γ-secretase in SKOV3.Methods Immunohistochemistry staining method was performed in 43 patients with epithelial ovarian carcinoma and 11 patients with benign epithelial ovarian tumor to detect the expression of Notch1,Jagged1 and NICD.The differences of expressionof Notch1,Jagged1 and NICD between malignant and benign ovarian tumors was compared and alsoanalyzed the correlation with clinicopathological parameters of ovarian carcinoma.Human serous ovarian cancer cell line SKOV3 and immortalized nontumorigenic ovarian epithelial cell line T29 were incubated in vitro.The activities of γ-secretase in SKOV3 and T29 with dimethyl sulfoxide (DMSO) and DAPT were detected respectively by Gal4VP16/UAS and dual luciferase reporter assay system.Results (1) The immunohistochemical composite scores (ICS) of Notch1 in epithelial ovarian carcinoma (6.7±2.2) were not significantly different with those in benign epithelial ovarian tumor (5.4± 2.7,P=0.153),while the ICS of Jagged 1 and NICD in epithelial ovarian carcinoma (5.3± 2.4,5.3± 2.3) were higher than those in benign epithelial ovarian tumor (1.6± 1.4,3.1± 1.7; all P＜0.01).The expression of Notch 1,Jagged 1 and N ICD had no correlation with patients' aged,history of carcinoma,ascites,the level of serum CA125,maximum length of ovarian tumor,Federation International of Gynecology and Obstetrics (FIGO) stage,grade and pathology subtypes (all P＞0.05).The hazard ratio between the high expression of Notch1,Jagged1,or NICD and the moderate to low expression of Notch1,Jagged1,or NICD,and Jagged1 were 0.771,1.648 and 1.316,respectively (all P＞0.05).The 5-year survival rate and median survival time between the high expression of Notch,Jagged 1 or NICD in subgroup and moderate to low expression in subgroup were of no difference (all P＞0.05).The activity of γ-secretase in SKOV3 was significantly higher than that in T29 [(12.2± 1.4)％,P=0.019].(2)After DAPT treated,the relative activity of γ-secretase in SKOV3 (50 μmol/L) was declined from (100.0±5.3)％ to (6.6±0.8)％ (P=0.001).Conclusions Jagged1 and NICD in Notch1 pathway may play a key role in the occurrence of ovarian carcinoma.The activity of γ-secretase in epithelial ovarian carcinoma was higher than that in ovarian epithelial cell which suggest that DAPT,γ-secretase inhibitor,may become the target of ovarian carcinoma treatment.
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Objective To investigate platelet α and β secretase activities and the amounts of platelet soluble fragment of APP (sAPPα) produced by α-secretase in patients with mild cognitive impairment (MCI) and Alzheimer's disease (AD).Methods The neurological functions of 48 nondemented patients,42 MCI and 40 AD patients were evaluated by neuropsychological examinations.The platelet α and β secretase activities and sAPPα production in each group were measured by fluorescence and Western blotting analysis respectively.Results The α secretase activities in non-demented,MCI and AD group were 100.0％ ± 10.6％,78.2％ ± 9.4％ and 61.8％ ± 7.2％ respectively.As compared with nondemented group,the α secretase activities in MCI and AD group were decreased (F =22.935,P =0.001).The α secretase activity in AD group was significantly lower than MCI group.The β secretase activities in non-demented,MCI and AD group were 100.0％ ± 11.2％,145.8％ ± 12.7％ and 189.8％ ± 14.2％respectively.The β secretase activities in MCI and AD group were significantly higher than that in nondemented group (F =16.368,P =0.001).The β secretase activity in AD group was significantly decreased as compared with MCI group.The sAPPα amounts in MCI group and AD group were all decreased as compared with that in control group; the sAPPo amount in AD patients was significantly decreased as compared with that in MCI group.Conclusions The platelet α secretase activity and its production sAPPα in MCI and AD patients are decreased,while β secretase activity is increased,as compared with that in control group; the altered α and β secretase activities may participate in the pathogenesis of MCI and AD patients and may have diagnostic potential for them.
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ObjectiveTo investigate the relationship between the polymorphisms of the promoter of a disintegrin and metalloproteinase 10(ADAM10) gene and sporadic Alzheimer's disease (SAD).Methods The promoter of ADAM10 gene in 10 controls and 10 SAD patients was sequenced.Three variations were found,then these variations in 298 SAD patients (SAD group) and 315 healthy controls (control group)were genotyped by using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP).ResultsThree polymorphisms were found in the promoter of ADAM10 gene: -279G/A (rs653765),- 630G/T( rs514049 ) and - 921GAGA/- ( rs33926666 ).For - 921GAGA/-,there were significant differences in genotype ( GAGA/GAGA:138 (46.3％ ),GAGA/-:155(52.0％),-/-:5(1.7％))and allele frequencies (GAGA:431 (73.6％),-:165 (27.7％) ) between SAD and control (genotype:x2 =34.130,P =0.000; allele:x2 =25.972,P =0.000). For - 279G/A,there were significant differences in genotype and allele frequencies between SAD and control in the subjects without ApoEε4 allele (genotype:x2 =8.734,P=0.013; allele:x2 =5.129,P=0.024). -279G and -921GAGA were relatively protective allele types for SAD,and they were not in linkage disequilibrium.ConclusionThe polymorphisms - 279G/A and - 921GAGA/- of ADAM10 are associated with SAD.Allele G or genotype G/G of -279G/A and the GAGA/GAGA genotype or the GAGA allele of -921GAGA/- might have a protective effect on SAD.
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ObjectiveTo investigate the distribution and expression of y-secretase subunit (APH-1)in the central nervous system (CNS) of APP/PS1 double transgenic Alzheimer's disease (AD) adult mouse model,and to detect the expression difference of APH-1 in developmental brain between AD model mouse and wild-type littermates in order to further clarify the relationship between APH-1 and AD. MethodsOffspring bred by APP/PS1 double transgenic AD mice were genotyped.Immunohistochemical staining was used to detect APH-1 distribution and expression in the CNS of adult APP/PS1 double transgenic AD mouse model,in the brain of AD model mouse and its wild-type littermates on postnatal day 1,7,21 and 120.Results APH-1 was widely expressed in almost all regions of the CNS,especially in the cerebral cortex,hippocampus,olfactory bulb,hypothalamus,ventral striatum,caudate putamen,raphe magnus nucleus,cerebellum,brainstem and spinal cord of the adult APP/PS1 double transgenic mice.APH-1 expression was higher in the cortex of both AD and wild type mouse on postnatal day 1 than on postnatal day 7 and 21 with increased level of APH-1 protein in adult mouse brain.APH-1 expression in the brain of AD mice was higher than in its wild type littermates at any stage(P＜0.05).Conclusions Distribution of APH-1 is ubiquitous and region-dependent in the CNS.The different distribution and expression between APP/PS1 double transgenic mouse model and its wild type littermate indicate that APH-1 may be related to AD.
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Objective To investigate the learning and memory functions,expression changes of disintegrin and metalloprotease 10 (ADAM10) mRNA in hippocampus in the aged rats with chronic cerebral hypoperfusion as well as the effect of atorvastatin on them.Methods A total of 72 rats were randomly divided into sham operation,cerebral hypoperfusion and atorvastatin treatment groups.A permanent bilateral common carotid artery occlusion (2VO)model was induced.Atorvastatin 10 mg/(kg · d) was administered orally after procedure in the atorvastatin treatment group.Real-time fluorescence quantitative polymerase chain reaction was used to detect the expression of ADAM10 mRNA in bilateral hippoocampus at 1,2,4,and 16 weeks after modeling,Results Two weeks after modeling,the learning and memory functions were decreased significantly in the cerebral hypoperfusion group compared to the sham operation group (P ＜ 0.05).At 4 and 16 weeks after modeling,they were further decreased (P ＜0.01); there were no significant differences in the learning and memory functions at 1,2,and 3 weeks after modeling between the atorvastatin treatment group and the cerebral hypoperfusion group,however,they were improved significantly at 16 weeks compared to the cerebral hypoperfusion group (P＜0.01).The expression of ADAM10 mRNA in hippocampus at different time points after modeling in the cerebral hypoperfusion group was down-regulated by 22％,43％,35％,and 50％,respectively compared to the sham operation group (all P ＜0.05).The expression of ADAM 10 mRNA in hippocampus at 2 weeks in the atorvastatin treatment group was higher than 22％ in the cerebral hypoperfusion group (P＜0.05).There were not significant differences at other time points.Conelusions Chronic cerebral hypoperfusion results in the down-regulation of the expression of ADAM10 mRNA in hippocampus in the aged rats,and atorvastatin may inhibit down-regulation of the expression of ADAM10 mRNA at early stage.
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Objective To study the expression and clinical significance of Notch3 and Notch intracellular domain (NICD) in ovarian carcinoma and the effects of N-[N-(3 ,5-difluorophenyl) acetyl-L-alanyl]-S-phenyl glycine t-butyl ester (DAPT), a γ-secretase inhibitor on the proliferation and apoptosis in OVCAR3, A2780 ovarian carcinoma cell lines. Methods Western blot was used to detect the expression of NICD in the tissues from 58 ovarian carcinomas patients and 21 normal ovarie, who were admitted in Peking University First Hospital from July 2006 to June 2009. Immunohistochemistry was also used to detect the expression of Notch3 in these tissues. The relationship with clinical features of ovarian carcinoma was also analyzed. Proliferation of OVCAR3 and A2780 ovarian cancer cells was determined by methyl thiazolyl tetrazolium (MTT) assay, cell cycles and apoptosis and index of proliferation were detected by flow cytometry method. The expression of NICD in OVCAR3 and A2780 cells incubated with DAPT was detected by western blot. Results (1)The expression level of NICD in ovarian carcinomas was significantly higher than that in normal ovarian tissues (1.64 ±0. 19 vs. 0.98 ±0.20;P <0.05). The NICD expression was higher in ovarian cancers with low grade or advanced stage than those in high-middle grade or early stage,respectively (1.90 ± 0. 22 vs. 1.25 ± 0. 21,1.80 ± 0. 21 vs. 1.21 ± 0. 15; all P < 0. 05). The Notch3 protein was stained positively in cytoplasm, nuclear and cell membrane. The expression of Notch3 was higher in ovarian carcinomas than that in normal ovaries [78% (45/58) vs. 24% (5/21); P < 0. 01]. While,there were no stasistical difference in different pathological types, stages, differentiation of ovarian carcinoma. There was no difference between the patients with adjuvant chemotherapy or not. (2)After OVCAR3 and A2780 cells incubated with DAPT 24, 48, 72 hours, NICD expression was significantly lower than that in control group (P < 0. 05). The effects of DAPT inhibited the proliferation and prompted the apoptosis of OVCAR3 and A2780 cells were depended on the concentrations and times. Conclusions Notch3 and NICD may play a key role in the occurrence and progress of ovarian carcinoma. The mechanism of DAPT inhibited the proliferation and prompted the apoptosis of OVCAR3 and A2780 cells may be due to decreased the formation of NICD.
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Objective To investigate the effect of phosphatidylinesitol-3 kinase/serine threonine kinase (PI3K/Akt) signaling pathway on expression of beta-site amyloid precursor protein cleaving enzyme-1 (BACE1) in the hippocampus neurons of rat brain. Methods Forty SD rats were randomly divided into 4 groups: blank control group, sham-operated group, insulin group and wortmannin group. Insulin or the specific inhibitor of PI3K, wortmannin was injected into hippocampus neurons to activate or inhibit the signaling pathway in insulin group or wortmannin group, respectively. Immunoprecipitation and Western blot were used to analyze the proteins levels of PI3K/Akt and BACE1. Results In insulin treatment group,among the proteins downstream of signaling pathway, expression of Akt increased (0. 952±0.060 vs 0.835±0.029,t=4.9150, P=0.0001), phospho-Akt set473 increased (0.800±0.075 vs 0.657± 0.025,t=4.5598, P=0.0002), phospho-GSK-3α decreased (0.604±0.062 vs 0.726±0.041, t= 3.5871, P=0.0018 ), and the expression of mature BACE1 and β-CTF significantly decreased. In wortmannin group, the expression of Akt and phospho-Akt ser473 were inhibited; phospho-GSK-3α increased ; mature BACEI (1.004±0.096) and β-CTF (1.031±0.048) increased (t=11.5980, P= 0.0000 and t =4.2194, P =0.0004, respectively). Conclusions PI3K/Akt signaling pathway might effect the expression of BACE1, in which impaired signaling pathway may cause the amyloid precursor protein to be easily processed by BACE1, and thus involves the pathology of Alzheimer' s disease.