1.Enhancing the expression level of human epidermal growth factor using the polyhedrin protein sequence of BmNPV.
Yuedong LI ; Xingyang WANG ; Shuohao LI ; Xiaofeng WU
Chinese Journal of Biotechnology 2024;40(11):4211-4218
Human epidermal growth factor (hEGF) can be applied in the treatment of surgical trauma (burns, scalds), tissue repair, skin moisturizing, beauty, skincare, etc. However, the low expression and high cost limit the application of hEGF. In order to improve the expression level of hEGF and reduce the production cost, considering the high expression of polyhedrin, this study fused a partial sequence of polyhedrin with hEGF and expressed the fused sequence by using a silkworm baculovirus expression vector system. In view of the small molecular weight of hEGF, we connected hEGF genes in series and optimized the codons to construct multiple fusion expression vectors by fusing different partial sequences of polyhedrin at the N-terminus. The results showed that through the above strategy, the protein expression level of hEGF was significantly increased. The expression vector containing three concatenated hEGF genes with optimized codons and fused with the sequence encoding 25 or 35 residues at the N-terminus of polyhedrin showed the highest expression level.
Humans
;
Epidermal Growth Factor/biosynthesis*
;
Genetic Vectors/genetics*
;
Recombinant Fusion Proteins/biosynthesis*
;
Animals
;
Bombyx/metabolism*
;
Occlusion Body Matrix Proteins/genetics*
;
Nucleopolyhedroviruses/genetics*
;
Amino Acid Sequence
2.Effect of Wnt/β-catenin signaling pathway in neural differentiation of human bone marrow mesenchymal stem cells.
Chinese Journal of Reparative and Reconstructive Surgery 2023;37(10):1276-1283
OBJECTIVE:
To explore the effect of basic fibroblast growth factor (bFGF), epidermal growth factor (EGF), and the combination of bFGF and EGF in the neural differentiation of human bone marrow mesenchymal stem cells (hBMSCs), and the role of Wnt/β-catenin signaling pathway in this process.
METHODS:
The identified 4th-generation hBMSCs were divided into five groups according to different induction conditions, namely control group (group A), EGF induction group (group B), bFGF induction group (group C), EGF and bFGF combined induction group (group D), and EGF, bFGF, and Dickkopf-related protein 1 (DKK-1) combined induction group (group E). After 7 days of continuous induction, the cell morphology was observed by inverted fluorescence phase contrast microscopy, levels of genes that were related to neural cells [Nestin, neuron-specific enolase (NSE), microtubule-associated protein 2 (MAP-2), and glial fibrillary acidic protein (GFAP)] and key components of the Wnt/β-catenin signaling pathway (β-catenin and Cyclin D1) were detected by RT-PCR, and the levels of proteins that were related to neural cells (Nestin and GFAP) as well as genes that were involved in Wnt/β-catenin signaling pathway [β-catenin, phosphorylation β-catenin (P-β-catenin), Cytoplasmic β-catenin, and Nuclear β-catenin] were explored by cellular immunofluorescence staining and Western blot.
RESULTS:
When compared to groups A and B, the typical neuro-like cell changes were observed in groups C-E, and most obviously in group D. RT-PCR showed that the relative expressions of Nestin, NSE, and MAP-2 genes in groups C-E, the relative expressions of GFAP gene in groups D and E, the relative expression of NSE gene in group B, the relative expressions of β-catenin gene in groups C and D, and the relative expressions of Cyclin D1 gene in groups B-D significantly increased when compared with group A ( P<0.05). Compared with group E, the relative expressions of Nestin, NSE, MAP-2, GFAP, β-catenin, and CyclinD1 genes significantly increased in group D ( P<0.05); compared with group C, the relative expression of Nestin gene in group D significantly decreased ( P<0.05), while NSE, MAP-2, and GFAP genes significantly increased ( P<0.05). The cellular immunofluorescence staining showed that the ratio of NSE- and GFAP-positive cells significantly increased in groups C-E than in group A, in group D than in groups C and E ( P<0.05). Western blot assay showed that the relative expression of NSE protein was significantly higher in groups C and D than in group A and in group D than in groups C and E ( P<0.05). In addition, the relative expression of GFAP protein was significantly higher in groups C-E than in group A and in group D than in group E ( P<0.05). Besides, the relative expressions of β-catenin, Cytoplasmic β-catenin, Nuclear β-catenin, and the ratio of Nuclear β-catenin to Cytoplasmic β-catenin were significantly higher in groups C and D than in group A and in group D than in group E ( P<0.05), whereas the relative expression of P-β-catenin protein was significantly lower in groups C and D than in group A and in group D than in group E ( P<0.05).
CONCLUSION
Different from EGF, bFGF can induce neural differentiation of hBMSCs. In addition, EGF can enhance the hBMSCs neural differentiation of bFGF, while the Wnt/β-catenin signaling pathway may play a positive regulatory role in these processes.
Humans
;
beta Catenin/metabolism*
;
Bone Marrow Cells
;
Cell Differentiation
;
Cells, Cultured
;
Epidermal Growth Factor/metabolism*
;
Mesenchymal Stem Cells
;
Wnt Signaling Pathway
;
Neurons
;
Fibroblast Growth Factor 2/metabolism*
3.Study on effect of extract from Tibetan medicine Urtica hyperborean on anti-prostatic hyperplasia.
Ri-Na SU ; Rong-Rui WEI ; Wei-Zao LUO ; Ji-Xiao ZHU ; Lu WANG ; Guo-Yue ZHONG
China Journal of Chinese Materia Medica 2019;44(9):1953-1959
In this study,mouse models of benign prostatic hyperplasia induced by subcutaneous injection of testosterone propionate was used to investigate the therapeutic effect and mechanism of Urtica hyperborean( UW) extracts on prostate hyperplasia in mice. The effects of UW extracts on prostate index,serum epidermal growth factor( EGF) and dihydrotestosterone( DHT) in model mice were observed,and the EGF and anti-apoptotic factor( Bcl-2) mRNA expression levels were detected as well as pathological changes in prostate tissue. The results showed that the ethyl acetate extraction and alcohol soluble fraction of the UW could significantly reduce the prostate index,reduce the serum DHT and EGF levels( P<0. 01),and significantly decrease the EGF and Bcl-2 mRNA expression( P<0. 01),significantly improved the morphological structure of prostate tissue. The above results confirmed that ethyl acetate extract and alcohol-soluble parts of UW have a good preventive effect on mice prostatic hyperplasia model,and its mechanism may be to reduce androgen levels by regulating polypeptide growth factors and/or inhibiting cell hyperproliferation and promoting apoptosis. This study laid the foundation for the further research on UW.
Animals
;
Dihydrotestosterone
;
blood
;
Epidermal Growth Factor
;
blood
;
Male
;
Medicine, Tibetan Traditional
;
Mice
;
Plant Extracts
;
pharmacology
;
Prostatic Hyperplasia
;
chemically induced
;
drug therapy
;
Proto-Oncogene Proteins c-bcl-2
;
metabolism
;
Testosterone Propionate
;
Urticaceae
;
chemistry
4.1-Methoxycarbony-β-carboline from Picrasma quassioides exerts anti-angiogenic properties in HUVECs in vitro and zebrafish embryos in vivo.
Qing-Hua LIN ; Wei QU ; Jian XU ; Feng FENG ; Ming-Fang HE
Chinese Journal of Natural Medicines (English Ed.) 2018;16(8):599-609
Angiogenesis is a crucial process in the development of inflammatory diseases, including cancer, psoriasis and rheumatoid arthritis. Recently, several alkaloids from Picrasma quassioides had been screened for angiogenic activity in the zebrafish model, and the results indicated that 1-methoxycarbony-β-carboline (MCC) could effectively inhibit blood vessel formation. In this study, we further confirmed that MCC can inhibit, in a concentration-dependent manner, the viability, migration, invasion, and tube formation of human umbilical vein endothelial cells (HUVECs) in vitro, as well as the regenerative vascular outgrowth of zebrafish caudal fin in vivo. In the zebrafish xenograft assay, MCC inhibited the growth of tumor masses and the metastatic transplanted DU145 tumor cells. The proteome profile array of the MCC-treated HUVECs showed that MCC could down-regulate several angiogenesis-related self-secreted proteins, including ANG, EGF, bFGF, GRO, IGF-1, PLG and MMP-1. In addition, the expression of two key membrane receptor proteins in angiogenesis, TIE-2 and uPAR, were also down-regulated after MCC treatment. Taken together, these results shed light on the potential therapeutic application of MCC as a potent natural angiogenesis inhibitor via multiple molecular targets.
Angiogenesis Inhibitors
;
chemistry
;
pharmacology
;
Animals
;
Carbolines
;
chemistry
;
pharmacology
;
Cell Movement
;
drug effects
;
Cell Proliferation
;
drug effects
;
Epidermal Growth Factor
;
genetics
;
metabolism
;
Fibroblast Growth Factors
;
genetics
;
metabolism
;
Human Umbilical Vein Endothelial Cells
;
cytology
;
drug effects
;
metabolism
;
Humans
;
Insulin-Like Growth Factor I
;
genetics
;
metabolism
;
Neovascularization, Physiologic
;
drug effects
;
Picrasma
;
chemistry
;
Plant Extracts
;
chemistry
;
pharmacology
;
Receptor, TIE-2
;
genetics
;
metabolism
;
Zebrafish
;
embryology
5.Effect of Optimized Concentrations of Basic Fibroblast Growth Factor and Epidermal Growth Factor on Proliferation of Fibroblasts and Expression of Collagen: Related to Pelvic Floor Tissue Regeneration.
Yuan-Yuan JIA ; Jing-Yi ZHOU ; Yue CHANG ; Fang AN ; Xiao-Wei LI ; Xiao-Yue XU ; Xiu-Li SUN ; Chun-Yang XIONG ; Jian-Liu WANG
Chinese Medical Journal 2018;131(17):2089-2096
Background:
Fibroblasts were the main seed cells in the studies of tissue engineering of the pelvic floor ligament. Basic fibroblast growth factor (bFGF) and epidermal growth factor (EGF) were widely studied but at various concentrations. This study aimed to optimize the concentrations of combined bFGF and EGF by evaluating their effects on proliferation and collagen secretion of fibroblasts.
Methods:
Fibroblasts were differentiated from rat adipose mesenchymal stem cells (ADSCs). Flow cytometry and immunohistochemistry were used for cell identification. The growth factors were applied at concentrations of 0, 1, 10, and 100 ng/ml as three groups: (1) bFGF alone, (2) EGF alone, and (3) bFGF mixed with EGF. Cell proliferation was evaluated by Cell Counting Kit-8 assays. Expression of Type I and III collagen (Col-I and Col-III) mRNAs was evaluated by real-time quantitative reverse transcription-polymerase chain reaction. Statistical analysis was performed with SPSS software and GraphPad Prism using one-way analysis of variance and multiple t-test.
Results:
ADSCs were successfully isolated from rat adipose tissue as identified by expression of typical surface markers CD29, CD44, CD90, and CD45 in flow cytometry. Fibroblasts induced from ADSC, compared with ADSCs, were with higher mRNA expression levels of Col I and Col III (F = 1.29, P = 0.0390). bFGF, EGF, and the mixture of bFGF with EGF can enhanced fibroblasts proliferation, and the concentration of 10 ng/ml of the mixture of bFGF with EGF displayed most effectively (all P < 0.05). The expression levels of Col-I and Col-III mRNAs in fibroblasts displayed significant increases in the 10 ng/ml bFGF combined with EGF group (all P < 0.05).
Conclusions
The optimal concentration of both bFGF and EGF to promote cell proliferation and collagen expression in fibroblasts was 10 ng/ml at which fibroblasts grew faster and secreted more Type I and III collagens into the extracellular matrix, which might contribute to the stability of the pelvic floor microenvironment.
Animals
;
Cell Proliferation
;
Cells, Cultured
;
Collagen
;
metabolism
;
Epidermal Growth Factor
;
physiology
;
Fibroblast Growth Factor 2
;
physiology
;
Fibroblasts
;
physiology
;
Pelvic Floor
;
Rats
;
Regeneration
6.EGF Induced RET Inhibitor Resistance in CCDC6-RET Lung Cancer Cells.
Hyun CHANG ; Ji Hea SUNG ; Sung Ung MOON ; Han Soo KIM ; Jin Won KIM ; Jong Seok LEE
Yonsei Medical Journal 2017;58(1):9-18
PURPOSE: Rearrangement of the proto-oncogene rearranged during transfection (RET) has been newly identified potential driver mutation in lung adenocarcinoma. Clinically available tyrosine kinase inhibitors (TKIs) target RET kinase activity, which suggests that patients with RET fusion genes may be treatable with a kinase inhibitor. Nevertheless, the mechanisms of resistance to these agents remain largely unknown. Thus, the present study aimed to determine whether epidermal growth factor (EGF) and hepatocyte growth factor (HGF) trigger RET inhibitor resistance in LC-2/ad cells with CCDC6-RET fusion genes. MATERIALS AND METHODS: The effects of EGF and HGF on the susceptibility of a CCDC6-RET lung cancer cell line to RET inhibitors (sunitinib, E7080, vandetanib, and sorafenib) were examined. RESULTS: CCDC6-RET lung cancer cells were highly sensitive to RET inhibitors. EGF activated epidermal growth factor receptor (EGFR) and triggered resistance to sunitinib, E7080, vandetanib, and sorafenib by transducing bypass survival signaling through ERK and AKT. Reversible EGFR-TKI (gefitinib) resensitized cancer cells to RET inhibitors, even in the presence of EGF. Endothelial cells, which are known to produce EGF, decreased the sensitivity of CCDC6-RET lung cancer cells to RET inhibitors, an effect that was inhibited by EGFR small interfering RNA (siRNA), anti-EGFR antibody (cetuximab), and EGFR-TKI (Iressa). HGF had relatively little effect on the sensitivity to RET inhibitors. CONCLUSION: EGF could trigger resistance to RET inhibition in CCDC6-RET lung cancer cells, and endothelial cells may confer resistance to RET inhibitors by EGF. E7080 and other RET inhibitors may provide therapeutic benefits in the treatment of RET-positive lung cancer patients.
Adenocarcinoma/drug therapy/*genetics
;
Cell Line, Tumor
;
Cetuximab/pharmacology
;
Drug Resistance, Neoplasm/drug effects/*genetics
;
Epidermal Growth Factor/metabolism/*pharmacology
;
*Gene Rearrangement
;
Hepatocyte Growth Factor/*pharmacology
;
Humans
;
Indoles/pharmacology
;
Lung Neoplasms/drug therapy/*genetics
;
MAP Kinase Signaling System
;
*Mutation
;
Niacinamide/analogs & derivatives/pharmacology
;
Phenylurea Compounds/pharmacology
;
Piperidines/pharmacology
;
Protein Kinase Inhibitors/therapeutic use
;
Proto-Oncogene Proteins c-ret/*antagonists & inhibitors/genetics
;
Pyrroles/pharmacology
;
Quinazolines/pharmacology
;
RNA, Small Interfering/pharmacology
;
Receptor, Epidermal Growth Factor/genetics/metabolism
;
Signal Transduction/drug effects
;
fms-Like Tyrosine Kinase 3/metabolism
7.Effects of culture supernatant of human amnion mesenchymal stem cells on biological characteristics of human fibroblasts.
Qi'er WU ; Lu LYU ; Haiming XIN ; Liang LUO ; Yalin TONG ; Yongliang MO ; Yigang YUE
Chinese Journal of Burns 2016;32(6):370-375
OBJECTIVETo investigate the effects of culture supernatant of human amnion mesenchymal stem cells (hAMSCs-CS) on biological characteristics of human fibroblasts.
METHODS(1) hAMSCs were isolated from deprecated human fresh amnion tissue of placenta and then sub-cultured. The morphology of hAMSCs on culture day 3 and hAMSCs of the third passage were observed with inverted phase contrast microscope. (2) Two batches of hAMSCs of the third passage were obtained, then the expression of vimentin of cells was observed with immunofluorescence method, and the expression of cell surface marker CD90, CD73, CD105, and CD45 was detected by flow cytometer. (3) hAMSCs-CS of the third passage at culture hour 72 were collected, and the content of insulin-like growth factor Ⅰ (IGF-Ⅰ), vascular endothelial growth factor (VEGF), epidermal growth factor (EGF), and basic fibroblast growth factor (bFGF) were detected by enzyme-linked immunosorbent assay. (4) Human fibroblasts were isolated from deprecated human fresh prepuce tissue of circumcision and then sub-cultured. Human fibroblasts of the third passage were used in the following experiments. Cells were divided into blank control group and 10%, 30%, 50%, and 70% hAMSCs-CS groups according to the random number table (the same grouping method below), with 48 wells in each group. Cells in blank control group were cultured with DMEM/F12 medium containing 2% fetal bovine serum (FBS), while cells in the latter 4 groups were cultured with DMEM/F12 medium containing corresponding volume fraction of hAMSCs-CS and 2% FBS. The proliferation activity of cells was detected by cell counting kit 8 and microplate reader at culture hour 12, 24, 48, and 72, respectively, and corresponding volume fraction of hAMSCs-CS which causing the best proliferation activity of human fibroblasts was used in the following experiments. (5) Human fibroblasts were divided into blank control group and 50% hAMSCs-CS group and treated as in (4), with 4 wells in each group, at post scratch hour (PSH) 0 (immediately after scratch), 12, 24, 48, and 72, the migration distance of cells was observed and measured with inverted phase contrast microscope. (6) Human fibroblasts were grouped and treated as in (5), with 3 battles in each group, and apoptosis rate of cells was detected by flow cytometer. Data were processed with analysis of variance of factorial design, analysis of variance for repeated measurement, one-way analysis of variance, LSD test, and t test.
RESULTS(1) On culture day 3, most hAMSCs were in large form, and spindle-shaped with much prominences like fibroblasts or in flat polygonal shape. hAMSCs of the third passage were spindle-shaped. The expression of vimentin of hAMSCs of the third passage was strongly positive, and the expressions of surface markers CD90, CD73, and CD105 of the cells were positive, while the expression of CD45 of the cells was negative. (2) The content of IGF-Ⅰ, VEGF, EGF, and bFGF in hAMSCs-CS were respectively (11.7±1.0), (316±68), (6.1±0.4), and (1.49±0.05) pg/mL. (3) At culture hour 12-72, the proliferation activity of human fibroblasts in each hAMSCs-CS group was significantly higher than that in blank control group (with P values below 0.01), and the proliferation activity of human fibroblasts in 50% hAMSCs-CS group was the highest. (4) The width of scratch in two groups was nearly the same at PSH 0. The migration distance of cells in 50% hAMSCs-CS group was significantly longer than that in blank control group at PSH 12-72 (with P values below 0.01). (5) The apoptosis rate of human fibroblasts in blank control group was (16.2±2.4)%, which was significantly higher than that in 50% hAMSCs-CS group [(7.4±3.6)%, t=6.710, P<0.01].
CONCLUSIONShAMSCs-CS can promote proliferation and migration of human fibroblasts and inhibit the apoptosis of human fibroblasts.
Amnion ; cytology ; Apoptosis ; Cell Movement ; Cell Proliferation ; Cells, Cultured ; Culture Media, Conditioned ; chemistry ; Enzyme-Linked Immunosorbent Assay ; Epidermal Growth Factor ; metabolism ; Female ; Fibroblast Growth Factor 2 ; metabolism ; Fibroblasts ; cytology ; drug effects ; Flow Cytometry ; Humans ; Insulin-Like Growth Factor I ; metabolism ; Male ; Mesenchymal Stromal Cells ; chemistry ; Pregnancy ; Vascular Endothelial Growth Factor A ; metabolism
8.Relationship between Preoperative 18F-Fluorodeoxyglucose Uptake and Epidermal Growth Factor Receptor Status in Primary Colorectal Cancer.
Yun Jung CHOI ; Min Jeong KIM ; Bong Hwa LEE ; Mi Jung KWON ; Hee Sung HWANG
Yonsei Medical Journal 2016;57(1):232-237
PURPOSE: Both 18F-fluorodeoxyglucose (18F-FDG) uptake and epidermal growth factor receptor (EGFR) status are prognostic variables of colorectal cancer (CRC). The aim of this study was to investigate a possible association between 18F-FDG uptake on preoperative positron emission tomography/computed tomography (PET/CT) and EGFR status in primary CRC. MATERIALS AND METHODS: Records of 132 patients (66 men and 66 women; mean age=67.1+/-11.1 years) who underwent 18F-FDG PET/CT for CRC staging and subsequent bowel resection were reviewed. In primary lesions, 18F-FDG uptake was semiquantitatively evaluated in terms of maximum standardized uptake value (SUVmax), and EGFR status was determined by immunohistochemistry. Associations of clinicopathological parameters and EGFR status were analyzed by Pearson's chi-square test, multiple logistic regression, and receiver operating characteristic curves. RESULTS: Eighty-six patients (65.2%) showed EGFR expression. SUVmax was significantly lower in EGFR-negative tumors than in EGFR-expressing tumors (10.0+/-4.2 vs. 12.1+/-2.1; p=0.012). It was the only significant parameter correlated with EGFR expression (odds ratio=2.457; relative risk=2.013; p=0.038). At the SUVmax threshold of 7.5, the sensitivity and specificity for predicting EGFR expression were 84.9% and 40.4%, respectively (area under the curve=0.624; p=0.019). CONCLUSION: Preoperative 18F-FDG uptake is slightly correlated with EGFR status in primary CRC. Preoperative SUVmax of 18F-FDG may have a limited role in predicting EGFR expression in such tumors because of its poor specificity.
Adult
;
Aged
;
Aged, 80 and over
;
Colorectal Neoplasms/metabolism/pathology/*radiography/*radionuclide imaging
;
Female
;
Fluorodeoxyglucose F18/*pharmacokinetics
;
Humans
;
Immunohistochemistry
;
Male
;
Middle Aged
;
Multimodal Imaging/*methods
;
Neoplasm Staging
;
Positron-Emission Tomography/*methods
;
Predictive Value of Tests
;
Prognosis
;
ROC Curve
;
Radiopharmaceuticals/*pharmacokinetics
;
Receptor, Epidermal Growth Factor/*metabolism
;
Sensitivity and Specificity
9.Detection of EGFR and KRAS Mutation by Pyrosequencing Analysis in Cytologic Samples of Non-Small Cell Lung Cancer.
Seung Eun LEE ; So Young LEE ; Hyung Kyu PARK ; Seo Young OH ; Hee Joung KIM ; Kye Young LEE ; Wan Seop KIM
Journal of Korean Medical Science 2016;31(8):1224-1230
EGFR and KRAS mutations are two of the most common mutations that are present in lung cancer. Screening and detecting these mutations are of issue these days, and many different methods and tissue samples are currently used to effectively detect these two mutations. In this study, we aimed to evaluate the testing for EGFR and KRAS mutations by pyrosequencing method, and compared the yield of cytology versus histology specimens in a consecutive series of patients with lung cancer. We retrospectively reviewed EGFR and KRAS mutation results of 399 (patients with EGFR mutation test) and 323 patients (patients with KRAS mutation test) diagnosed with lung cancer in Konkuk University Medical Center from 2008 to 2014. Among them, 60 patients had received both EGFR and KRAS mutation studies. We compared the detection rate of EGFR and KRAS tests in cytology, biopsy, and resection specimens. EGFR and KRAS mutations were detected in 29.8% and 8.7% of total patients, and the positive mutation results of EGFR and KRAS were mutually exclusive. The detection rate of EGFR mutation in cytology was higher than non-cytology (biopsy or resection) materials (cytology: 48.5%, non-cytology: 26.1%), and the detection rate of KRAS mutation in cytology specimens was comparable to non-cytology specimens (cytology: 8.3%, non-cytology: 8.7%). We suggest that cytology specimens are good alternatives that can readily substitute tissue samples for testing both EGFR and KRAS mutations. Moreover, pyrosequencing method is highly sensitive in detecting EGFR and KRAS mutations in lung cancer patients.
Adult
;
Aged
;
Aged, 80 and over
;
Carcinoma, Non-Small-Cell Lung/genetics/metabolism/*pathology
;
DNA Mutational Analysis
;
DNA, Neoplasm/chemistry/metabolism
;
Female
;
Humans
;
Lung Neoplasms/genetics/metabolism/*pathology
;
Male
;
Middle Aged
;
Mutation
;
Receptor, Epidermal Growth Factor/*genetics/metabolism
;
Retrospective Studies
;
ras Proteins/*genetics/metabolism
10.The RAS/PI3K Pathway is Involved in the Impairment of Long-term Potentiation Induced by Acute Aluminum Treatment in Rats.
Jing SONG ; Ying LIU ; Hui Fang ZHANG ; Qiao NIU
Biomedical and Environmental Sciences 2016;29(11):782-789
OBJECTIVETo explore the role of RAS/PI3K pathway in the impairment of long-term potentiation (LTP) induced by acute aluminum (Al) treatment in rats in vivo.
METHODSFirst, different dosages of aluminum-maltolate complex [Al(mal)3] were given to rats via acute intracerebroventricular (i.c.v.) injection. Following Al exposure, the RAS activity of rat hippocampus were detected by ELISA assay after the hippocampal LTP recording by field potentiation technique in vivo. Second, the antagonism on the aluminum-induced suppression of hippocampal LTP was observed after the treatment of the RAS activator epidermal growth factor (EGF). Finally, the antagonism on the downstream molecules (PKB activity and the phosphorylation of GluR1 S831 and S845) were tested by ELISA and West-blot assays at the same time.
RESULTSWith the increasing aluminum dosage, a gradually decreasing in RAS activity of the rat hippocampus was produced after a gradually suppressing on LTP. The aluminum-induced early suppression of hippocampal LTP was antagonized by the RAS activator epidermal growth factor (EGF). And the EGF treatment produced changes similar to those observed for LTP between the groups on PKB activity as well as the phosphorylation of GluR1 S831 and S845.
CONCLUSIONThe RAS→PI3K/PKB→GluR1 S831 and S845 signal transduction pathway may be involved in the inhibition of hippocampal LTP by aluminum exposure in rats. However, the mechanisms underlying this observation need further investigation.
Aluminum ; toxicity ; Animals ; Epidermal Growth Factor ; metabolism ; Hippocampus ; drug effects ; metabolism ; Injections, Intraventricular ; Long-Term Potentiation ; drug effects ; Male ; Phosphatidylinositol 3-Kinases ; metabolism ; Phosphorylation ; drug effects ; Proto-Oncogene Proteins c-akt ; metabolism ; Random Allocation ; Rats ; Receptors, AMPA ; metabolism ; Signal Transduction ; drug effects ; ras Proteins ; metabolism

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