ADAM Proteins ; genetics ; ADAM17 Protein ; Animals ; Gene Library ; Genetic Vectors ; Male ; Mice ; Two-Hybrid System Techniques

Alzheimer's disease(AD) patients in China have been surging, and the resultant medical burden and care demand have a huge impact on the development of individuals, families, and the society. The active component compound of Epimedii Folium, Astragali Radix, and Puerariae Lobatae Radix(YHG) can regulate the expression of iron metabolism-related proteins to inhibit brain iron overload and relieve hypofunction of central nervous system in AD patients. Hepcidin is an important target regulating iron metabolism. This study investigated the effect of YHG on the expression of a disintegrin and metalloprotease-17(ADAM17), a key enzyme in the hydrolysis of β amyloid precursor protein(APP) in HT22 cells, by mediating hepcidin. To be specific, HT22 cells were cultured in vitro, followed by liposome-mediated siRNA transfection to silence the expression of hepcidin. Real-time PCR and Western blot were performed to examine the silencing result and the effect of YHG on hepcidin in AD cell model. HT22 cells were randomized into 7 groups: control group, Aβ25-35 induction(Aβ) group, hepcidin-siRNA(siRNA) group, Aβ25-35 + hepcidin-siRNA(Aβ + siRNA) group, Aβ25-35+YHG(Aβ+YHG) group, hepcidin-siRNA+YHG(siRNA+YHG) group, Aβ25-35+hepcidin-siRNA+YHG(Aβ+siRNA+YHG) group. The expression of ADAM17 mRNA in cells was detected by real-time PCR, and the expression of ADAM17 protein by immunofluorescence and Western blot. Immunofluorescence showed that the ADAM17 protein expression was lower in the Aβ group, siRNA group, and Aβ+siRNA group than in the control group(P<0.05) and the expression was lower in the Aβ+siRNA group(P<0.05) and higher in the Aβ+YHG group(P<0.05) than in the Aβ group. Moreover, the ADAM17 protein expression was lower in the Aβ+siRNA group(P<0.05) and higher in the siRNA+YHG group(P< 0.05) than in the siRNA group. The expression was higher in the Aβ+siRNA+YHG group than in the Aβ+siRNA group(P<0.05). The results of Western blot and real-time PCR were consistent with those of immunofluorescence. The experiment showed that YHG induced hepcidin to up-regulate the expression of ADAM17 in AD cell model and promote the activation of non-starch metabolic pathways, which might be the internal mechanism of YHG in preventing and treating AD.
ADAM17 Protein ; Alzheimer Disease/genetics* ; Amyloid beta-Peptides ; Drugs, Chinese Herbal/pharmacology* ; Hepcidins/genetics* ; Humans ; Pueraria

Tumour necrosis factor-alpha converting enzyme (TACE) is the major protease responsible for processing proTNF from membrane-anchored precursor into secreted TNF-alpha. It was validated that TACE is involved in many diseases such as arthritis, multiple sclerosis and Alzheimers, therefore it represents a novel and significant target for therapeutic intervention in a variety of inflammatory and neuroimmunological diseases. To obtain the recombinant TACE ectodomain and use it as a selective molecule for the screening of TACE peptide inhibitors, the cDNA coded for catalytic domain (T800) and full-length ectodomain (T1300) of TACE were amplified by RT-PCR, the expression plasmid was constructed by inserting T800/T1300 into plasmid pET-28a/pET-28c and transformed into E. coli BL21 (DE3). SDS-PAGE and Western blotting analysis revealed that T800/T1300 was highly expressed in the form of inclusion body being induced by IPTG. After Ni2+ -NTA resin affinity chromatography, the purity of the recombinant T800/T1300 protein was more than 90%. T800 and T1300 protein were used in the screening of TACE-binding peptides from the phage display random 15-peptide library. After four rounds of biopanning, the positive phage clones were analyzed by ELISA, competitive inhibition assay and DNA sequencing. A common amino acid sequence-TRWLVYFSRPYLVAT was found and synthesized. The synthetic peptide was shown to bind to TACE and inhibit the TNF-alpha release from LPS-stimulated human peripheral blood mononuclear cells (PBMC) up to 60.3%. FACS analysis revealed that the peptide mediated the accumulation of TNF-alpha on LPS-stimulated PBMC surface. These results demonstrate that the TACE-binding peptide is an effective antagonist of TACE and the deduced motif might be applied to molecular design of anti-inflammation drugs.
ADAM Proteins ; antagonists & inhibitors ; biosynthesis ; genetics ; ADAM17 Protein ; Amyloid Precursor Protein Secretases ; Animals ; Humans ; Mice ; Peptide Library ; Peptides ; chemistry ; Recombinant Proteins ; biosynthesis ; genetics ; Tumor Necrosis Factor-alpha

In order to investigate the effects of LPS on the TACE gene transcription and expression and its regulating effect on the TM-TNF secretion, in vitro studies were carried out on HL-60 cells stimulated by LPS. TACE, TNF-alpha mRNA levels were detected by Dot-Elisa and the distribution of membrane molecules determined by flow cytometry assay and indirect immunofluorescence. The results showed that: (1) TACE was detected in or on HL-60 cells and it is predominantly localized on cell surface and to a perinuclear compartment. (2) LPS induced a time dependent increasement of TNF-alpha mRNA and enhanced TNF conversion with decreasing distribution of TNF in cell surface and increasing secretion of TNF protein. Such conversion could be inhibited by TACE ODN. (3) LPS also induced time-dependently increased expression of TACE gene and activation of its function. On the other hand, TACE protein in cell lysate and on cell surface was decreased. It was suggested that TACE molecular structure might change following its mediating membrane-anchored molecular secretion.
ADAM Proteins ; ADAM17 Protein ; Gene Expression ; HL-60 Cells ; Humans ; Lipopolysaccharides ; pharmacology ; Metalloendopeptidases ; biosynthesis ; genetics ; RNA, Messenger ; biosynthesis ; genetics ; Transcription, Genetic ; Tumor Necrosis Factor-alpha ; biosynthesis ; genetics

Glycoprotein (GP) Ibα ectodomain shedding has important implications for thrombosis and hemostasis. A disintegrin and metalloproteinase 17 (ADAM17) was identified to play an essential role in agonist induced GPIbα shedding. The relationship of GPIbα shedding and ADAM17 in the acute stage of atherosclerotic ischemic stroke (AIS) patients has not been thoroughly studied. A total of 306 patients and 230 controls matched for age, sex, race, history of hypertension and diabetes mellitus were enrolled in the study. GPIbα, ADAM17, glycocalicin were detected by flow cytometry, Western blotting, and enzyme-linked immunosorbent assay (ELISA) respectively. Compared with the control group, the expression of GPIbα in patients with acute ischemic stroke was significantly lower (P=0.000, P<0.01). Plasma glycocalicin and ADAM17 in AIS group were higher than those in control group (P=0.699, P=0.000). Pearson's analysis showed glycocalicin bore no correlation with GPIbα in AIS patients (r=0.095, P>0.05). GPIbα and National Institute of Health Stroke Scale (NIHSS) had negative correlation (r=-0.514, P<0.01). Our findings indicate that ADAM17 may be a risk factor for ischemic stroke in Chinese and the expression of GPIbα can serve as a measure for stroke severity.
ADAM Proteins ; blood ; ADAM17 Protein ; Biomarkers ; blood ; Blood Platelets ; metabolism ; Brain Ischemia ; blood ; diagnosis ; China ; Female ; Humans ; Intracranial Arteriosclerosis ; blood ; diagnosis ; Male ; Middle Aged ; Platelet Glycoprotein GPIb-IX Complex ; metabolism ; Reproducibility of Results ; Sensitivity and Specificity ; Severity of Illness Index ; Stroke ; blood ; diagnosis

ADAM Proteins ; genetics ; ADAM17 Protein ; Adrenergic beta-Antagonists ; therapeutic use ; Animals ; Male ; Metoprolol ; therapeutic use ; Myocardial Infarction ; drug therapy ; physiopathology ; RNA, Messenger ; analysis ; Rats ; Rats, Wistar ; Tumor Necrosis Factor-alpha ; genetics ; Ventricular Function, Left ; drug effects ; Ventricular Remodeling ; drug effects

BACKGROUNDChronic obstructive pulmonary disease (COPD) is associated not only with airway inflammation characterized by mucin hypersecretion but also with systemic inflammation. Tumor necrosis factor alpha (TNF-alpha) is found to take part in systemic inflammation, and ErbB3 plays an important role in mucin hypersecretion of COPD. Since TNF-alpha converting enzyme (TACE) is involved in the activation of both TNF-alpha and ErbB3, we established rat models of COPD to investigate the expressions of TACE, TNF-alpha and ErbB3 and to explore the correlations among TACE, TNF-alpha and ErbB3 respectively.

METHODSThirty Wistar male rats were randomly divided into COPD group (group C, n = 10), saline solution parallel group (group P, n = 8), and normal control group (group N, n = 8). Group C was challenged with passive cigarette smoking and intratracheal instillation of lipopolysaccharide. Six weeks later pulmonary functions were tested, bronchoalveolar fluid and arterial blood gases were assayed, and histopathological evaluations were performed in turn. The expressions of TACE, TNF-alpha and ErbB3 in lungs of all rats were determined histochemically.

RESULTSThe expressions of TACE, TNF-alpha and ErbB3 were significantly higher in group C than in group N (P < 0.01). The contents of TNF-alpha in serum (P < 0.01) and bronchoalveolar lavage fluid (BALF) (P < 0.01) were elevated more significantly in group C than in group N. A positive correlation existed between TACE and TNF-alpha (r = 0.784, P < 0.01) and between TACE and ErbB3 (r = 0.526, P < 0.01) respectively.

CONCLUSIONSTNF-alpha and ErbB3 are involved in the pathogenesis of COPD. TACE contributes to the progress of COPD indirectly through the function of TNF-alpha and ErbB3.

ADAM Proteins ; analysis ; physiology ; ADAM17 Protein ; Animals ; Bronchoalveolar Lavage Fluid ; chemistry ; Immunohistochemistry ; Lung ; physiopathology ; Male ; Pulmonary Disease, Chronic Obstructive ; metabolism ; pathology ; Rats ; Rats, Wistar ; Receptor, ErbB-3 ; analysis ; physiology ; Tumor Necrosis Factor-alpha ; analysis

OBJECTIVETo construct the bait vector pGBKT7-TACEc (cytoplasmic tail of tumor necrosis factor-alpha converting enzyme) of Macthmaker GAL4 Two-hybrid System 3, and to test whether it has self-activation and toxic action.

METHODSTACEc gene was amplified by RT-PCR from the mouse testis, and the EcoRI and BamHI sites were introduced into it. The TACEc gene, after sequenced, was cloned into pGBKT7. Self-activation and toxic action of the recombination vector pGBKT7-TACEc was tested.

RESULTSThe pGBKT7-TACEc vector was successfully constructed and proved of no self-activation and toxic action.

CONCLUSIONThe pGBKT7-TACEc can be applied to the screening of the mouse testis cDNA library in the yeast two-hybrid system.

ADAM Proteins ; genetics ; metabolism ; ADAM17 Protein ; Animals ; Cloning, Molecular ; DNA, Complementary ; Male ; Mice ; Mice, Inbred BALB C ; Plasmids ; RNA ; isolation & purification ; Reverse Transcriptase Polymerase Chain Reaction ; Testis ; metabolism ; Two-Hybrid System Techniques ; Yeasts ; metabolism

OBJECTIVETo investigate the main proteinases responsible for CD16b shedding under different stimulators.

METHODSHEK293 cell line stably expressing CD16b was constructed by lentivirus system. The cell line was then overexpressed with a disintegrin and metalloproteinase 10 (ADAM10) or ADAM17, suppressed with short hairpin RNA of ADAM10 or ADAM17, and reconstituted with ADAM10 or ADAM17, respectively. After each treatment, the cell line was stimulated with ionomycin or phorbol 12-myristate- 13-acetate (PMA) for 12 hours. The soluble CD16b released from cell membrane was detected by immunoprecipition and immunoblot. Quantitation was then implemented to compare the amount of soluble CD16b in cell supernatant after stimulation.

RESULTSHEK293 cell line stably expressing CD16b was successfully established. When CD16b expressing cell line was overexpressed with ADAM10, shedding of CD16b was increased after stimulation with ionomycin but not PMA; when the cell line overexpressed with ADAM17, shedding of CD16b was increased after stimulation with PMA but not ionomycin. Similarly, when ADAM10 was suppressed by short hairpin RNA, CD16b shedding was decreased after stimulation with ionomycin; when ADAM17 was suppressed by short hairpin RNA, CD16b shedding was decreased after stimulation with PMA. The shedding of CD16b was increased again when CD16b expressing cell line was reconstituted with ADAM10 and stimulated by ionomycin or reconstituted with ADAM17 and stimulated by PMA.

CONCLUSIONSBoth ADAM10 and ADAM17 could shed CD16b, but they possess differed preferences. ADAM10 is the main sheddase under stimulation of ionomycin, while ADAM17 is the main sheddase under stimulation of PMA.

ADAM Proteins ; genetics ; metabolism ; physiology ; ADAM10 Protein ; ADAM17 Protein ; Amyloid Precursor Protein Secretases ; genetics ; metabolism ; physiology ; Calcium Ionophores ; pharmacology ; Carcinogens ; pharmacology ; Cells, Cultured ; Drug Evaluation, Preclinical ; GPI-Linked Proteins ; metabolism ; Gene Knockdown Techniques ; HEK293 Cells ; Humans ; Ionomycin ; pharmacology ; Membrane Proteins ; genetics ; metabolism ; physiology ; Protein Processing, Post-Translational ; drug effects ; Protein Transport ; drug effects ; Proteolysis ; drug effects ; Receptors, IgG ; metabolism ; Tetradecanoylphorbol Acetate ; pharmacology ; Transfection

The sigma-1 receptor is a molecular chaperone protein highly enriched in the brain. Recent studies linked it to many diseases, such as drug addition, Alzheimer's disease, stroke, depression, and even cancer. Sigma-1 receptor is enriched in lipid rafts, which are membrane microdomains essential in signaling processes. One of those signaling processes is ADAM17- and ADAM10-dependent ectodomain shedding. By using an alkaline phosphatase tagged substrate reporter system, we have shown that ADAM10-dependent BTC shedding was very sensitive to both membrane lipid component change and sigma-1 receptor agonist DHEAS treatment while ADAM17-dependent HB-EGF shedding was not; and overexpression of sigma-1 receptor diminished ADAM17- and ADAM10-dependent shedding. Our results indicate that sigma-1 receptor plays an important role in modifying the function of transmembrane proteases.
ADAM Proteins ; metabolism ; ADAM10 Protein ; ADAM17 Protein ; Amyloid Precursor Protein Secretases ; metabolism ; Animals ; Betacellulin ; COS Cells ; Cercopithecus aethiops ; Gene Expression ; HEK293 Cells ; Heparin-binding EGF-like Growth Factor ; Humans ; Intercellular Signaling Peptides and Proteins ; metabolism ; Membrane Microdomains ; metabolism ; Membrane Proteins ; metabolism ; Receptors, sigma ; agonists ; metabolism