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1.
Ecotoxicol Environ Saf ; 269: 115810, 2024 Jan 01.
Article En | MEDLINE | ID: mdl-38100849

BACKGROUND: Jujuboside B (JuB) is the main bioactive saponin component of Chinese anti-insomnia herbal medicine Ziziphi Spinosae Semen, which has been reported to possess varied pharmacological functions. Even though it has been traditionally used to treat inflammation- and toxicity-related diseases, the effects of JuB on acetaminophen (APAP) overdose-induced hepatotoxicity have not been determined yet. METHODS: C57BL/6 J mice were pre-treated with JuB (20 or 40 mg/kg) for seven days before APAP (400 mg/kg) injection. After 24 h of APAP treatment, serum, and liver tissues were collected to evaluate the therapeutic effects. To investigate whether the Nrf2-STING signaling pathway is involved in the protective effects of JuB against APAP-induced hepatotoxicity, the mice received the DMXAA (the specific STING agonist) or ML385 (the specific Nrf2 inhibitor) during the administration of JuB, and Hematoxylin-eosin staining, Real-time PCR, immunohistochemical, and western blot were performed. RESULTS: JuB pretreatment reversed APAP-induced CYP2E1 accumulations and alleviated APAP-induced acute liver injury. Furthermore, JuB treatment significantly inhibited oxidative stress and the pro-inflammatory cytokines, as well as alleviated hepatocyte apoptosis induced by APAP. Besides, our result also demonstrated that JuB treatment upregulated the levels of total Nrf2, facilitated its nuclear translocation, upregulated the expression of HO-1 and NQO-1, and inhibited the APAP-induced STING pathway activation. Finally, we verified that the beneficial effects of JuB were weakened by DMXAA and ML385. CONCLUSION: Our study suggested that JuB could ameliorate APAP-induced hepatic damage and verified a previously unrecognized mechanism by which JuB prevented APAP-induced hepatotoxicity through adjusting the Nrf2-STING pathway.


Chemical and Drug Induced Liver Injury , Saponins , Animals , Mice , Acetaminophen/toxicity , Acetaminophen/metabolism , NF-E2-Related Factor 2/genetics , NF-E2-Related Factor 2/metabolism , Protective Agents/pharmacology , Chemical and Drug Induced Liver Injury/drug therapy , Chemical and Drug Induced Liver Injury/etiology , Chemical and Drug Induced Liver Injury/prevention & control , Mice, Inbred C57BL , Signal Transduction , Oxidative Stress , Liver , Saponins/pharmacology , Saponins/therapeutic use
2.
Sci Rep ; 13(1): 20969, 2023 11 28.
Article En | MEDLINE | ID: mdl-38017264

Hepatocellular carcinoma (HCC) is a lethal malignancy worldwide with an increasing number of new cases each year. Apolipoprotein (APOL) isoforms have been explored for their associations with HCC.The GSE14520 cohort was used for training data; The Cancer Genome Atlas (TCGA) database was used for validated data. Diagnostic, prognostic significance and mechanisms were explored using these cohorts. Risk score models and nomograms were constructed using prognosis-related isoforms and clinical factors for survival prediction. Oncomine and HCCDB databases were further used for validation of diagnostic, prognostic significance. APOL1, 3, and 6 were differentially expressed in two cohorts (all P ≤ 0.05). APOL1 and APOL6 had diagnostic capacity whereas APOL3 and APOL6 had prognostic capacity in two cohorts (areas under curves [AUCs] > 0.7, P ≤ 0.05). Mechanism studies demonstrated that APOL3 and APOL6 might be involved in humoral chemokine signaling pathways (all P ≤ 0.05). Risk score models and nomograms were constructed and validated for survival prediction of HCC. Moreover, diagnostic values of APOL1 and weak APOL6 were validated in Oncomine database (AUC > 0.700, 0.694); prognostic values of APOL3 and APOL6 were validated in HCCDB database (all P < 0.05). Differentially expressed APOL1 and APOL6 might be diagnostic biomarkers; APOL3 and APOL6 might be prognostic biomarkers of RFS and OS for HCC via chemokine signaling pathways.


Carcinoma, Hepatocellular , Liver Neoplasms , Humans , Carcinoma, Hepatocellular/diagnosis , Carcinoma, Hepatocellular/genetics , Apolipoprotein L1/genetics , Liver Neoplasms/diagnosis , Liver Neoplasms/genetics , Protein Isoforms , Biomarkers , Chemokines , Prognosis
3.
Sci Rep ; 13(1): 16859, 2023 10 06.
Article En | MEDLINE | ID: mdl-37803063

Worldwide, cancer is a huge burden, and each year sees an increase in its incidence. RAB (Ras-related in brain) 13 is crucial for a number of tumor types. But more research on RAB13's tumor-related mechanism is still required. This study's goal was to investigate RAB13's function in human pan-cancer, and we have also preliminarily explored the relevant mechanisms. To investigate the differential expression, survival prognosis, immunological checkpoints, and pathological stage of RAB13 in human pan-cancer, respectively, databases of TIMER2.0, GEPIA 2, and UALCAN were employed. CBioPortal database was used to analyze the mutation level, meanwhile, PPI network was constructed based on STRING website. The putative functions of RAB13 in immunological infiltration were investigated using single sample gene set enrichment analysis (ssGSEA). The mechanism of RAB13 in hepatocellular cancer was also briefly investigated by us using gene set enrichment analysis (GSEA). RAB13 was differentially expressed in a number of different cancers, including liver hepatocellular carcinoma (LIHC), stomach adenocarcinoma (STAD), etc. Additionally, RAB13 overexpression in LGG and LIHC is associated with a worse prognosis, including overall survival (OS) and disease-free survival (DFS). Then, we observed that early in BLCA, BRAC, CHOL, ESCA, HNSC, KICH, KIRC, LIHC, LUAD, LUSC, and STAD, the level of RAB13 expression was raised. Next, we found that "amplification" was the most common mutation in RAB13. The expression of SLC39A1, JTB, SSR2, SNAPIN, and RHOC was strongly positively linked with RAB13, according to a correlation study. RAB13 favorably regulated B cell, CD8 + T cell, CD4 + T cell, macrophage, neutrophil, and dendritic cell in LIHC, according to immune infiltration analysis. Immune checkpoint study revealed a positive correlation between RAB13 expression and PD1, PDL1, and CTLA4 in LIHC. According to GSEA, RAB13 is involved in a number of processes in LIHC, including MTORC1 signaling, MYC targets v1, G2M checkpoint, MITOTIC spindle, DNA repair, P53 pathway, glycolysis, PI3K-AKT-MTOR signaling, etc. RAB13 is a possible therapeutic target in LIHC and can be used as a prognostic marker.


Adenocarcinoma , Carcinoma, Hepatocellular , Liver Neoplasms , Stomach Neoplasms , Humans , Phosphatidylinositol 3-Kinases , Carcinoma, Hepatocellular/genetics , rab GTP-Binding Proteins/genetics
4.
Front Immunol ; 14: 1269451, 2023.
Article En | MEDLINE | ID: mdl-37868994

Regulation of cell mortality for disease treatment has been the focus of research. Ferroptosis is an iron-dependent regulated cell death whose mechanism has been extensively studied since its discovery. A large number of studies have shown that regulation of ferroptosis brings new strategies for the treatment of various benign and malignant diseases. Iron excess and lipid peroxidation are its primary metabolic features. Therefore, genes involved in iron metabolism and lipid metabolism can regulate iron overload and lipid peroxidation through direct or indirect pathways, thereby regulating ferroptosis. In addition, glutathione (GSH) is the body's primary non-enzymatic antioxidants and plays a pivotal role in the struggle against lipid peroxidation. GSH functions as an auxiliary substance for glutathione peroxidase 4 (GPX4) to convert toxic lipid peroxides to their corresponding alcohols. Here, we reviewed the researches on the mechanism of ferroptosis in recent years, and comprehensively analyzed the mechanism and regulatory process of ferroptosis from iron metabolism and lipid metabolism, and then described in detail the metabolism of GPX4 and the main non-enzymatic antioxidant GSH in vivo.


Ferroptosis , Iron Overload , Humans , Phospholipid Hydroperoxide Glutathione Peroxidase/metabolism , Iron/metabolism , Glutathione Peroxidase/metabolism , Lipid Peroxidation/physiology , Antioxidants/metabolism , Glutathione/metabolism
5.
BMC Gastroenterol ; 23(1): 216, 2023 Jun 20.
Article En | MEDLINE | ID: mdl-37340445

BACKGROUND: Hepatocellular carcinoma (HCC) is a long-term malignancy that causes high morbidities and mortalities worldwide. Notably, long non-coding RNAs (LncRNAs) have been identified as candidate targets for malignancy treatments. METHODS: LncRNA LINC01116 and its Pearson-correlated genes (PCGs) were identified and analyzed in HCC patients. The diagnostic and prognostic value of the lncRNA was evaluated using data from The Cancer Genome Atlas (TCGA). Further, we explored the target drugs of LINC01116 for clinical application. Relationships between immune infiltration and PCGs, methylation and PCGs were explored. The diagnostic potentials were then validated by Oncomine cohorts. RESULTS: LINC01116 and the PCG OLFML2B are differentially and highly expressed in tumor tissues (both P ≤ 0.050). We found that LINC01116, TMSB15A, PLAU, OLFML2B, and MRC2 have diagnostic potentials (all AUC ≥ 0.700, all P ≤ 0.050) while LINC01116 and TMSB15A have prognostic significance (both adjusted P ≤ 0.050). LINC01116 was enriched in the vascular endothelial growth factor (VEGF) receptor signaling pathway, mesenchyme morphogenesis, etc. After that, candidate target drugs with potential clinical significance were identified: Thiamine, Cromolyn, Rilmenidine, Chlorhexidine, Sulindac_sulfone, Chloropyrazine, and Meprylcaine. Analysis of immune infiltration revealed that MRC2, OLFML2B, PLAU, and TMSB15A are negatively associated with the purity but positively associated with the specific cell types (all P < 0.050). Analysis of promoter methylation demonstrated that MRC2, OLFML2B, and PLAU have differential and high methylation levels in primary tumors (all P < 0.050). Validation results of the differential expressions and diagnostic potential of OLFML2B (Oncomine) were consistent with those obtained in the TCGA cohort (P < 0.050, AUC > 0.700). CONCLUSIONS: Differentially expressed LINC01116 could be a candidate diagnostic and an independent prognostic signature in HCC. Besides, its target drugs may work for HCC therapy via the VEGF receptor signaling pathway. Differentially expressed OLFML2B could be a diagnostic signature involved in HCC via immune infiltrates.


Carcinoma, Hepatocellular , Liver Neoplasms , RNA, Long Noncoding , Humans , Carcinoma, Hepatocellular/genetics , Carcinoma, Hepatocellular/pathology , RNA, Long Noncoding/genetics , RNA, Long Noncoding/metabolism , Liver Neoplasms/genetics , Liver Neoplasms/pathology , Vascular Endothelial Growth Factor A , Prognosis
6.
Sci Rep ; 11(1): 23356, 2021 12 02.
Article En | MEDLINE | ID: mdl-34857818

PCBP1 is a multifunctional RNA-binding protein (RBP) expressed in most human cells and is involved in posttranscriptional gene regulation. PCBP1 regulates the alternative splicing, translation and RNA stability of many cancer-related genes and has been identified as a potential tumour suppressor gene. PCBP1 inhibits the invasion of hepatocellular carcinoma (HCC) cells, but there are few studies on the specific regulatory target and mechanism of RBPs in HCC, and it is unclear whether PCBP1 plays a role in tumour metastasis as a splicing factor. We analysed the regulation of gene expression by PCBP1 at the transcriptional level. We obtained and analysed PCBP1-knockdown RNA-seq data and eCLIP-seq data of PCBP1 in HepG2 cells and found that PCBP1 widely regulates the alternative splicing and expression of genes enriched in cancer-related pathways, including extracellular matrix, cell adhesion, small molecule metabolic process and apoptosis. We validated five regulated alternative splicing events affected by PCBP1 using RT-qPCR and found that there was a significant difference in the expression of APOC1 and SPHK1 between tumour and normal tissues. In this study, we provided convincing evidence that human PCBP1 profoundly regulates the splicing of genes associated with tumour metastasis. These findings provide new insight into potential markers or therapeutic targets for HCC treatment.


Alternative Splicing , Biomarkers, Tumor/metabolism , Carcinoma, Hepatocellular/pathology , DNA-Binding Proteins/metabolism , Gene Expression Regulation, Neoplastic , Liver Neoplasms/pathology , RNA Splicing Factors/metabolism , RNA-Binding Proteins/metabolism , Biomarkers, Tumor/genetics , Carcinoma, Hepatocellular/genetics , Carcinoma, Hepatocellular/metabolism , DNA-Binding Proteins/genetics , Gene Expression Profiling , Humans , Liver Neoplasms/genetics , Liver Neoplasms/metabolism , Neoplasm Metastasis , Prognosis , RNA Splicing Factors/genetics , RNA-Binding Proteins/genetics , Tumor Cells, Cultured
7.
J Med Chem ; 64(9): 5863-5873, 2021 05 13.
Article En | MEDLINE | ID: mdl-33886333

Although multivalent glycosidase inhibitors have shown enhanced glycosidase inhibition activities, further applications and research directions need to be developed in the future. In this paper, two positional isomeric perylene bisimide derivatives (PBI-4DNJ-1 and PBI-4DNJ-2) with 1-deoxynojirimycin conjugated were synthesized. Furthermore, PBI-4DNJ-1 and PBI-4DNJ-2 showed positional isomeric effects on the optical properties, self-assembly behaviors, glycosidase inhibition activities, and hypoglycemic effects. Importantly, PBI-4DNJ-1 exhibited potent hypoglycemic effects in mice with 41.33 ± 2.84 and 37.45 ± 3.94% decreases in blood glucose at 15 and 30 min, respectively. The molecular docking results showed that the active fragment of PBI-4DNJ-1 has the highest binding energy (9.649 kcal/mol) and the highest total hydrogen bond energy (62.83 kJ/mol), which were related to the positional isomeric effect on the hypoglycemic effect in mice. This work introduced a new means to develop antihyperglycemic agents in the field of multivalent glycomimetics.


Glucosamine/analogs & derivatives , Glycoside Hydrolases/metabolism , Hypoglycemic Agents/chemistry , Imides/chemistry , Perylene/analogs & derivatives , Administration, Oral , Animals , Binding Sites , Blood Glucose/analysis , Glucosamine/chemistry , Glycoside Hydrolases/antagonists & inhibitors , Hydrogen Bonding , Hypoglycemic Agents/administration & dosage , Hypoglycemic Agents/metabolism , Isomerism , Kinetics , Mice , Molecular Conformation , Molecular Docking Simulation , Perylene/chemistry , Protein Binding , Thermodynamics
8.
J Appl Clin Med Phys ; 21(8): 256-262, 2020 Aug.
Article En | MEDLINE | ID: mdl-32510768

This retrospective study was to compare the image quality of right coronary artery (RCA) and effective radiation dose on prospective ECG-gated method between 320 row computed tomography (CT) and 2nd generation (128-slice) dual source CT. A total of 215 candidates underwent CT coronary angiography using prospective ECG-gated method, 120 patients enrolled in 320 row CT group, and 95 patients in dual source CT group. We divided RCA image quality scores as 1/2/3/4, which means excellent/good/adequate/not assessable and heart rates were considered, as well as the radiation dose. There is no statistically significant difference of RCA image quality of Score 1/2 between 320 row CT and 2nd generation dual source CT, but lower heart rate (<70/min) improved RCA image quality. Meanwhile, the 2nd generation dual source CT scan have significant lower radiation dose. For patients with high level heart rate variation, both prospective ECG-gated method of 320 row CT scan (Toshiba) and 2nd generation dual source CT scan (Siemens) basically provided good image quality on RCA. There is an advantage of effective radiation dose reduction in prospective ECG-gated method using the 2nd generation dual source CT scan. After the iodine contrast agent was injected into elbow vein, the threshold triggering method was used to carry out prospective gated scanning, and the acquired fault image was reconstructed by the standard post-processing software of each manufacturer. The radiation dose value is obtained through the dose report automatically generated after each scan.


Coronary Vessels , Electrocardiography , Cardiac-Gated Imaging Techniques , Coronary Angiography , Coronary Vessels/diagnostic imaging , Humans , Prospective Studies , Radiation Dosage , Retrospective Studies , Tomography, X-Ray Computed
9.
Molecules ; 25(1)2019 Dec 22.
Article En | MEDLINE | ID: mdl-31877851

This study was conducted to develop a self-assembled direct competitive enzyme-linked immunosorbent assay (dcELISA) kit for the detection of deoxynivalenol (DON) in food and feed grains. Based on the preparation of anti-DON monoclonal antibodies, we established a standard curve with dcELISA and optimized the detection conditions. The performance of the kit was evaluated by comparison with high-performance liquid chromatography (HPLC). The minimum detection limit of DON with the kit was 0.62 ng/mL, the linear range was from 1.0 to 113.24 ng/mL and the half-maximal inhibition concentration (IC50) was 6.61 ng/mL in the working buffer; there was a limit of detection (LOD) of 62 ng/g, and the detection range was from 100 to 11324 ng/g in authentic agricultural samples. We examined four samples of wheat bran, wheat flour, corn flour and corn for DON recovery. The average recovery was in the range of 77.1% to 107.0%, and the relative standard deviation (RSD) ranged from 4.2% to 11.9%. In addition, the kit has the advantages of high specificity, good stability, a long effective life and negligible sample matrix interference. Finally, wheat samples from farms in the six provinces of Henan, Anhui, Hebei, Shandong, Jiangsu and Gansu in China were analyzed by the kit. A total of 30 samples were randomly checked (five samples in each province), and the results were in good agreement with the standardized HPLC method. These tests showed that the dcELISA kit had good performance and met relevant technical requirements, and it had the characteristics of accuracy, reliability, convenience and high-throughput screening for DON detection. Therefore, the developed kit is suitable for rapid screening of DON in marketed products.


Enzyme-Linked Immunosorbent Assay/methods , Food Contamination/analysis , Trichothecenes/analysis , Triticum/chemistry , China , Chromatography, High Pressure Liquid , Dietary Fiber/analysis , Edible Grain/chemistry , Flour/analysis , Limit of Detection , Zea mays/chemistry
10.
J Mater Chem B ; 7(8): 1270-1275, 2019 02 28.
Article En | MEDLINE | ID: mdl-32255166

A self-assembled multivalent glycosidase inhibitor based on perylene bisimide-deoxynojirimycin conjugates was constructed, inhibited α-mannosidase and exhibited a Ki value of 38 nM, increased approximately 2763-fold compared with the control drug (miglitol). Furthermore, the postprandial blood glucose (PBG) level in mice of PBI-DNJ was firstly studied. PBI-DNJ exhibited a hypoglycaemic effect in vivo. Importantly, this work developed a new means to explore the hypoglycaemic effect in mice based on self-assembled glycosidase inhibitors.


Glucosamine/analogs & derivatives , Glycoside Hydrolases/antagonists & inhibitors , Imides/metabolism , Perylene/analogs & derivatives , 1-Deoxynojirimycin/metabolism , Animals , Glucosamine/metabolism , Humans , Mice , Perylene/metabolism
11.
Bioorg Med Chem Lett ; 28(4): 742-747, 2018 02 15.
Article En | MEDLINE | ID: mdl-29342415

A series of novel N,N-bis(3-aminopropyl)methylamine bridged bis-naphthalimide derivatives NI1-NI8 containing saturated nitrogenous heterocycles were designed and synthesized, their cytotoxic activities against Hela, MCF-7, A549 and MGC-803 cells were investigated, Compounds NI1-NI4 modified with piperidine and piperazine exhibited good and selective cytotoxic activity, for instance, compounds NI1 and NI4 showed potent cytotoxic activity against Hela cells and MGC-803 cells with the IC50 values of 2.89, 060, 2.73 and 1.60 µM, respectively, better than the control drug (Amonafide). However, compounds NI5-NI8 conjugated with pyrrole derivatives showed weak cytotoxic activities against the all tested cell lines. Furthermore, their DNA binding properties, fluorescence imaging and cell cycle were investigated. Interestingly, compounds NI1 and NI4 showed fluorescence enhancement because of the strong binding with Ct-DNA, and exhibited fluorescence imaging with Hela cells on the lysosomes.


Antineoplastic Agents/pharmacology , Fluorescent Dyes/pharmacology , Lysosomes/metabolism , Naphthalimides/pharmacology , Adenine , Animals , Antineoplastic Agents/chemical synthesis , Antineoplastic Agents/chemistry , Cell Line, Tumor , DNA/chemistry , Drug Screening Assays, Antitumor , Fluorescence , Fluorescent Dyes/chemical synthesis , Fluorescent Dyes/chemistry , Humans , Microscopy, Confocal , Microscopy, Fluorescence , Naphthalimides/chemical synthesis , Naphthalimides/chemistry , Nucleic Acid Conformation , Organophosphonates , Piperazines/chemical synthesis , Piperazines/chemistry , Piperazines/pharmacology , Piperidines/chemical synthesis , Piperidines/chemistry , Piperidines/pharmacology , S Phase Cell Cycle Checkpoints/drug effects , Transition Temperature , Zebrafish
12.
Pol J Vet Sci ; 19(1): 65-73, 2016.
Article En | MEDLINE | ID: mdl-27096789

Porcine epidemic diarrhea virus (PEDV) is having a severe effect on the pig breeding industry in central China. The mucosa and the content of the small intestine from newborn pre-weaned piglets with diarrhea were tested for the presence of PEDV by molecular and morphologic methods, and found to be positive. Negative-staining electron microscopy (EM) revealed the presence of coronavirus- like particles in the samples. The result of molecular detection by nested RT-PCR based on the amplification of the M gene was positive. Using a novel alternative method we successfully propagated the PEDV strain (CH/QX-2) in Vero cells, confirmed by ultrathin sections of the cells and Immunofluorescence assay (IFA). Phylogenetic analysis based on the partial S gene showed that the CH/QX-2 isolate was genetically closer to strains more commonly found in China, but differed genetically from two domestic strains (CH/S, 1986 and LZC, 2007), Korean strains (DR13, 2007), and the vaccine strain (CV777 vs) currently being used in China. CH/QX-2 formed a unique clade in the derived phylogenetic tree indicating that the CH/QX-2 strain currently circulating in central China is a new variant of PEDV. This study extends current knowledge on the diversity and epidemiology of PEDV.


Coronavirus Infections/veterinary , Porcine epidemic diarrhea virus/genetics , Porcine epidemic diarrhea virus/isolation & purification , Spike Glycoprotein, Coronavirus/metabolism , Swine Diseases/virology , Amino Acid Sequence , Animals , China/epidemiology , Cloning, Molecular , Coronavirus Infections/epidemiology , Coronavirus Infections/virology , Gene Expression Regulation, Viral , Molecular Sequence Data , Phylogeny , Porcine epidemic diarrhea virus/ultrastructure , Reverse Transcriptase Polymerase Chain Reaction , Spike Glycoprotein, Coronavirus/genetics , Swine , Swine Diseases/epidemiology
13.
J Zhejiang Univ Sci B ; 12(6): 460-7, 2011 Jun.
Article En | MEDLINE | ID: mdl-21634039

A rapid sample treatment procedure for the gas chromatography-tandem mass spectrometry (GC-MS) determination of 19-nortestosterone (19-NT) in animal tissues has been developed. In our optimized procedures, enzymatic hydrolysis with ß-glucuronidase from Escherichia coli was performed in an acetate buffer (pH 5.2, 0.2 mol/L). Next, the homogenate was mixed with methanol and heated at 60 °C for 15 min, then placed in an ice-bath at -18 °C for 2 h. After liquid-liquid extraction with n-hexane, the analytes were subjected to a normal-phase solid phase extraction (SPE) C18 cartridge for clean-up. The dried organic extracts were derivatized with heptafluorobutyric anhydride (HFBA), and then the products were injected into GC-MS. Using electron impact mass spectrometry (EI-MS) with positive chemical ionization (PCI), four diagnostic ions (m/z 666, 453, 318, and 306) were determined. A standard calibration curve over the concentration range of 1-20 ng/g was reached, with Y=467084X-68354 (R²=0.9997) for 19-NT, and the detection limit was 0.3 ng. When applied to spiked samples collected from bovine and ovine, the recoveries ranged from 63% to 101% with relative standard deviation (RSD) between 2.7% and 8.9%. The procedure is a highly efficient, sensitive, and more economical method which offers considerable potential to resolve cases of suspected nandrolone doping in husbandry animals.


Drug Residues/analysis , Gas Chromatography-Mass Spectrometry/methods , Meat/analysis , Nandrolone/analysis , Tandem Mass Spectrometry/methods , Animals , Cattle , Nandrolone/isolation & purification , Sheep , Solid Phase Extraction
14.
J Mol Biol ; 374(3): 777-90, 2007 Nov 30.
Article En | MEDLINE | ID: mdl-17963781

Smad1, a downstream regulator of the bone morphogenetic protein (BMP) receptors, is tightly regulated by the ubiquitin-proteasomal degradation system. To dissect the mechanisms that underlie the regulation of Smad1, it is important to investigate the specific ubiquitination site(s) in Smad1. Here we report that the alpha-NH(2) group of the N terminus and the epsilon-NH(2) groups of internal lysine residues 116, 118 and 269 (K116, K118 and K269) of Smad1 are ubiquitin acceptor sites mediated by the carboxyl terminus of Hsc70-interacting protein (CHIP). The in vitro degradation assay indicates that ubiquitination at the N terminus partially contributes to the degradation of Smad1. Furthermore, we demonstrate that the ubiquitination level of pseudo-phosphorylated Smad1 by CHIP is stronger than that of wild-type Smad1 and can be strongly inhibited by a phosphorylated tail of Smad1, PIS(pS)V(pS). Third, our results indicate that Hsp70 facilitates CHIP-mediated poly-ubiquitination of Smad1 whereas it attenuates CHIP-meditated mono-ubiquitination of Smad1. Finally, consistent with the in vitro observation, we show that CHIP preferentially mediates the degradation of phospho-Smad1/5 in vivo. Taken together, these results provide us a hint that CHIP might preferentially regulate phosphorylated Smad1 and thus the BMP signaling.


Bone Morphogenetic Proteins/metabolism , Signal Transduction , Smad1 Protein/metabolism , Ubiquitin-Protein Ligases/metabolism , Ubiquitin/metabolism , Blotting, Western , Cell Line , Humans , Hydrolysis , Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
15.
Colloids Surf B Biointerfaces ; 40(3-4): 133-6, 2005 Feb 25.
Article En | MEDLINE | ID: mdl-15708501

The TGF-beta superfamily signaling pathway regulates many important biological processes, including cell growth, differentiation and embryonic pattern formation. Smad1, a member of this signaling pathway that functions downstream of serine/threonine kinase receptors, has ability to interact with carboxyl terminus of Hsc70-interacting protein (CHIP), which is an E3 ubiquitin ligase in other cases. It has been reported that Smurf1, a member of the Hect family E3 ubiquitin ligases, can target Smad1 to 26S proteasome for degradation. In this paper, we studied the interaction of Smad1 and CHIP by combination of surface plasmon resonance and supported monolayer approach. The specific binding of Smad1 to CHIP indicates that the degradation of Smad1 may also be mediated by CHIP, and CHIP may play an essential role in the TGF-beta signaling pathway.


DNA-Binding Proteins/metabolism , Lysine/analogs & derivatives , Trans-Activators/metabolism , Ubiquitin-Protein Ligases/metabolism , DNA-Binding Proteins/chemistry , Histidine , Humans , Kinetics , Oleic Acids , Smad Proteins , Smad1 Protein , Smad4 Protein , Succinates , Surface Plasmon Resonance , Trans-Activators/chemistry , Ubiquitin-Protein Ligases/chemistry
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