In order to study the physicochemical characteristics of cytosolic PrP (CytoPrP) and evaluate its possible influence on cell viability, a recombinant plasmid expressing human CytoPrP eukaryoticly was constructed and transfected into human neuroblastoma cell line SH-SY5Y transiently. Proteinase-resistant activities of CytoPrP were evaluated by a proteinase K (PK) digestion and cytotoxic effects of CytoPrP were tested by MTT assay and Trypan Blue cell-counting. The presence of CytoPrP in cytoplasm after transfection was controlled by the presence of protease inhibitor. Compared with wild-type PrP, CytoPrP possessed relatively stronger PK-resistant activities. Obvious cytotoxic effects were observed in the cells after inducement of CytoPrP in cytoplasm by protease inhibitor, showing a dose-dependent manner. The results provide useful scientific evidences for further studies of potential role of CytoPrP in pathological mechanism of prion disease.
Cell Line, Tumor ; Cell Survival ; Cytosol ; chemistry ; Endopeptidase K ; pharmacology ; Humans ; Prions ; genetics ; physiology ; Transfection

Studies on coat protein I (COPI) have contributed to a basic understanding of how coat proteins generate vesicles to initiate intracellular transport. The core component of the COPI complex is coatomer, which is a multimeric complex that needs to be recruited from the cytosol to membrane in order to function in membrane bending and cargo sorting. Previous structural studies on the clathrin adaptors have found that membrane recruitment induces a large conformational change in promoting their role in cargo sorting. Here, pursuing negative-stain electron microscopy coupled with single-particle analyses, and also performing CXMS (chemical cross-linking coupled with mass spectrometry) for validation, we have reconstructed the structure of coatomer in its soluble form. When compared to the previously elucidated structure of coatomer in its membrane-bound form we do not observe a large conformational change. Thus, the result uncovers a key difference between how COPI versus clathrin coats are regulated by membrane recruitment.
ADP-Ribosylation Factor 1 ; chemistry ; metabolism ; Animals ; Coatomer Protein ; chemistry ; metabolism ; Cytosol ; chemistry ; metabolism ; GTPase-Activating Proteins ; chemistry ; metabolism ; Humans ; Membranes, Artificial ; Rats

This experiment was designed to explore the pattern of K562 and HL60 leukemia cells death, the effects on their cell cycle and the cytoplasmic free calcium concentration ([Ca2+]i) induced by 5-aminolaevulinic acid-based photodynamic therapy (ALA-PDT). Under the transmission electron microscope (TEM), two kinds of leukemia cells' ultrastructure were observed. Flow cytometry combined with Annexin V-FITC/PI labeling was used to detect the pattern of K562 and HL60 cells' death induced by ALA-PDT. Flow cytometry combined with PI labeling was used to analyze the change in the cell cycle induced by ALA-PDT, and confocal laser scanning microscopy (CLSM) combining with calcium fluorescence probe was used to detect the change in the cytoplasmic free calcium concentration ([Ca2+]i). Immediately after irradiation, many typical apoptotic bodies were seen in the cells treated. Most of the cells treated were necrotic at 24 hours following irradiation. Flow cytometry analysis suggested that the main patterns of the cells' death were apoptosis immediately after irradiation and necrosis post-apoptosis at 24 hours post irradiation. Immediately and 24 hours after irradiation, the proportion of S phase of K562 was 57. 67% +/- 1.13% and 84.77% +/- 6.20% respectively, and the proportion of S phase of HL60 was 74.60% +/- 7.27% and 84.60% 1.74% respectively. Both [Ca+]i of the treated K562 and HL60 were increased obviously. In the best experiment condition, the initial pattern of the K562 and HL60 leukemia cells' death induced by PDT was apoptosis and the main pattern was necrosis post apoptosis. The two kinds of cells were arrested at S phase by ALA-PDT. During the death of the leukemia cells, the increase in intracellular free calcium concentration could be responsible for the ALA photodynamically induced damage to K562 and HL60 cells.
Aminolevulinic Acid ; pharmacology ; Apoptosis ; drug effects ; Calcium ; chemistry ; Cell Division ; drug effects ; Cytosol ; chemistry ; HL-60 Cells ; drug effects ; Humans ; K562 Cells ; drug effects ; Photochemotherapy

To investigate the existence of nongenomic action of 17β-estradiol (E(2)) in the delayed implantation mouse endometrial stromal cells, the changes in intracellular calcium concentration ([Ca(2+)](i)) and the upstream of calcium signal in vitro were detected. The experiment was composed of two parts. Firstly, the change in [Ca(2+)](i) in endometrial stromal cells induced by E(2) under different conditions was detected. The mice were divided into 6 groups as follows: 0.1% dimethylsulfoxide (DMSO) control group, 1×10(-8) mol/L bovine serum albumin (BSA) control group, 1×10(-8) mol/L E(2) group, 1×10(-8) mol/L E(2) conjugated with BSA (E(2)-BSA) group, 1×10(-8) mol/L E(2) + calcium-free medium group, 1×10(-8) mol/L E(2) + 5 mg/mL tamoxifen group, with 4 mice in each group. The endometrial tissue was obtained from delayed implantation mice at pregnant day 7, and digested by incubation of tissue minces in Hankos balanced salts (HBSS, pH 7.2), which contained glucose (1 g/L), and collagenase I (0.125%), for 1 h at 37 degrees C. The stromal cells were preloaded with 2.5 mmol/L Fluo-3/AM, a fluorescent probe of calcium, for 30 min. A confocal laser scanning microscope, which fixed the wave length of excitation and emission at 488 nm and 526 nm, respectively, was used to detect the change in [Ca(2+)](i). Secondly, the mechanism of E(2) effects in endometrial stromal cells was investigated. Immunofluorescent method was used to detect the change in phosphorylation of phospholipase C (PLC) before and after the stromal cells were treated with E(2) for 5 min, 15 min, and 30 min. Seven delayed implantation mice were used. The results were as follows. [Ca(2+)](i) increased immediately and reached the maximum at 15 min after the stromal cells were treated with 1×10(-8) mol/L E(2) and returned to the normal level at 30 min. In E(2)-BSA group and E(2) + calcium-free medium group the same results were obtained as that in E(2) group, but there was no increase of [Ca(2+)](i) in DMSO and BSA groups. Tamoxifen, a traditional antagonist of estrogen receptor, did not inhibit the increase in [Ca(2+)](i) induced by E(2). Immunofluorescent results showed that the change in phosphorylated-PLC level had the same trend as [Ca(2+)](i) after the cells were treated with E(2). Compared with that in the control group, the immunofluorescent intensity increased at the beginning and achieved the maximum at 15 min (P<0.001), then declined to the normal level at 30 min. These results suggest that the rapid response of [Ca(2+)](i) induced by E(2) in the endometrial stromal cells in delayed implantation mice is possibly carried out through a nongenomic pathway, and the transmembrane signal transduction is related to the phosphorylation of PLC in this process.
Animals ; Calcium ; chemistry ; Culture Media ; Cytosol ; chemistry ; Endometrium ; cytology ; Estradiol ; pharmacology ; Female ; Mice ; Phosphorylation ; Pregnancy ; Receptors, Estrogen ; Signal Transduction ; Stromal Cells ; cytology ; drug effects ; Tamoxifen

A novel exonuclease protection mediated PCR assay (EPM-PCR) to detect the interaction of protein and DNA at a dioxin-responsive enhancer (DRE) upstream of the CYP1A1 gene in rat hepatic cytosol was established. A double-stranded DNA fragment containing two binding sites was designed and incubated with the aryl hydrocarbon receptor (AhR) transformed by 2,3,7,8-tetrachlorodibenzo-p dioxin (TCDD) to generate TCDD: AhR: DNA complex which could protect receptor-binding DNA against exonuclease II (Exo III) digestion. With Exo III treatment, free DNAs were digested and receptor-bound DNAs remained that could be amplified by PCR. By agarose gel electrophoreses a clear band (285bp) was detected using TCDD-treated sample, while nothing with control samples. To detect transformed AhR-DRE complex, 2 fmol DNAs and 3 ug cytosol proteins were found to be sufficient in the experiment. Compared with gel retardation assay, this new method is more sensitive for monitoring the Ah receptor-enhancer interaction without radioactive pollution.
Binding Sites ; Cytochrome P-450 CYP1A1/*genetics ; Cytosol/metabolism ; DNA-Binding Proteins/chemistry ; Exodeoxyribonucleases/chemistry ; Liver/*metabolism ; Polymerase Chain Reaction ; Rats, Sprague-Dawley ; Receptors, Aryl Hydrocarbon/*chemistry ; Tetrachlorodibenzodioxin/*analogs & derivatives ; Tetrachlorodibenzodioxin/chemistry

OBJECTIVE: Reactive oxygen species (ROS) are involved in a variety of biological phenomena and serve both deleterious and beneficial roles. ROS quantification and assessment of reaction networks are desirable but difficult because of their short half-life and high reactivity. Here, we describe a pro-oxidative model in a single human lung carcinoma SPC-A-1 cell that was created by application of extracellular H₂O₂ stimuli. METHODS: Modified microfluidics and imaging techniques were used to determine O₂ ^•- levels and construct an O₂ ^•- reaction network. To elucidate the consequences of increased O₂ ^•- input, the mitochondria were given a central role in the oxidative stress mode, by manipulating mitochondria-interrelated cytosolic Ca²⁺ levels, mitochondrial Ca²⁺ uptake, auto-amplification of intracellular ROS and the intrinsic apoptotic pathway. RESULTS AND CONCLUSIONS Results from a modified microchip demonstrated that 1 mmol/L H₂O₂ induced a rapid increase in cellular O₂ ^•- levels (>27 vs. >406 amol in 20 min), leading to increased cellular oxidizing power (evaluated by ROS levels) and decreased reducing power (evaluated by glutathione (GSH) levels). In addition, we examined the dynamics of cytosolic Ca²⁺ and mitochondrial Ca²⁺ by confocal laser scanning microscopy and confirmed that Ca²⁺ stores in the endoplasmic reticulum were the primary source of H₂O₂-induced cytosolic Ca²⁺ bursts. It is clear that mitochondria have pivotal roles in determining how exogenous oxidative stress affects cell fate. The stress response involves the transfer of Ca²⁺ signals between organelles, ROS auto-amplification, mitochondrial dysfunction, and a caspase-dependent apoptotic pathway.
Apoptosis ; Calcium/metabolism* ; Calcium Signaling ; Caspases/metabolism* ; Cell Line, Tumor ; Cell Lineage ; Cytosol/metabolism* ; Glutathione/metabolism* ; Humans ; Hydrogen Peroxide/chemistry* ; Mitochondria/metabolism* ; Oxidation-Reduction ; Oxidative Stress ; Reactive Oxygen Species/metabolism* ; Signal Transduction ; Superoxides/chemistry*

OBJECTIVETo evaluate the effect of glycogen on calcium concentration of rabbit donor liver during ischemia-reperfusion period.

METHODSDonor group (n=21) was divided into 3 subgroups randomly: Group A (n=7): fasting for 24 hours before harvesting; Group B (n=7): normal laboratory chew; Group C (n=7): normal laboratory chew plus glucose supplement intravenously. Based on the self-created animal model for ischemia-reperfusion, the levels of glycogen content, ATP level, viability of Ca(2+)ATPase and plasmic free Ca(2+) concentration ([Ca(2+)]i) of liver tissue were measured.

RESULTSBefore cold preservation, there was a significant difference of glycogen content among the three groups at all time points except at the end of rewarming period. ATP level and Ca(2+)ATPase viability were significantly higher in group C than in other two groups. But the plasmic free Ca(2+) concentration was lower in groups with higher glycogen content.

CONCLUSIONSDonor liver with high glycogen content can provide relatively sufficient ATP, maintain better Ca(2+)ATPase viability and prevent plasmic free Ca(2+) concentration overloading. This maybe an important mechanism for glycogen to ameliorate ischemia-reperfusion injury to the donor livers.

Adenosine Triphosphate ; metabolism ; Animals ; Calcium ; metabolism ; Calcium-Transporting ATPases ; metabolism ; Cytosol ; chemistry ; Female ; Glycogen ; metabolism ; Liver Diseases ; enzymology ; metabolism ; Liver Transplantation ; physiology ; Male ; Models, Animal ; Rabbits ; Reperfusion Injury ; enzymology ; metabolism

The mitochondrial pathway of swine influenza virus (SIV)-induced apoptosis was investigated using porcine kidney (PK-15) cells, swine testicle (ST) cells, and HeLa cervical carcinoma cells which are known not to support viral replication. As judged by cell morphology, annexin V staining, and DNA fragmentation, PK-15 and ST cells infected with three different subtypes of SIV (H1N1, H3N2, and H1N2) were obviously killed by apoptosis, not necrosis. SIV infection in PK-15 and HeLa cells was shown to decrease the cellular levels of Bcl-2 protein compared to that of mock-infected control cells at 24 h post-infection, whereas expression levels of Bax protein increased in the PK-15 cells, but did not increase in HeLa cells by SIV infection. Cytochrome c upregulation was also observed in cytosolic fractions of the PK-15 and HeLa cells infected with SIV. Apoptosome (a multi-protein complex consisting of cytochrome c, Apaf-1, caspase-9, and ATP) formation was confirmed by immunoprecipitation using cytochrome c antibody. Furthermore, SIV infection increased the cellular levels of TAJ, an activator of the JNK-stressing pathway, and the c-Jun protein in the PK-15 and HeLa cells. Taken together, these results suggest that the mitochondrial pathway should be implicated in the apoptosis of PK-15 cells induced by SIV infection.
Animals ; Annexin A5/metabolism ; *Apoptosis ; Blotting, Western ; Cell Fractionation ; Cell Line ; Comparative Study ; Cytochrome c Group/metabolism ; Cytosol/chemistry ; DNA Fragmentation ; Enzyme Activation ; Gene Expression Regulation, Viral ; Hela Cells ; Humans ; Influenza A virus/*physiology ; Kinetics ; Mitochondria/metabolism/*physiology ; Precipitin Tests ; Proto-Oncogene Proteins c-bcl-2/genetics/metabolism ; Research Support, Non-U.S. Gov't ; Swine ; bcl-2-Associated X Protein/genetics/metabolism

OBJECTIVETo investigate the antiinflammatory activities of aqueous extract of Occimum gratissmium (OGE) with emphasis on expression of proinflammatory cytokines in Lipopolysaccharide (LPS)-stimulated epithelial cell BEAS-2B.

METHODSEffects of OGE on cell viability were determined by MTT assay. mRNA expression were analyzed by and reverse transcription polymerase chain reaction (RT-PCR) and quantitative real-time PCR. Activation of kinase cascades was investigated by immunoblot. Intracellular reactive oxygen species (ROS) was analyzed by flow cytometry.

RESULTSOGE (<200 μg/mL) treatment or pretreatment and following LPS exposure slightly affected viability of BEAS-2B cells. Increase of interleukin (IL)-6 and IL-8 and the elevated level of intracellular ROS in LPS-stimulated BEAS-2B cells were diminished by OGE pretreatment in a dose-dependent manner. OGE suppressed inflammatory response-associated mitogen-activated protein kinases (MAPKs) and Akt activation. Additionally, OGE pretreatment increased level of cellular inhibitor of κBα (IκBα) and inhibited nuclear translocation of nuclear factor kappa B (NF-κB).

CONCLUSIONThese findings indicate that significant suppression of IL-6 and IL-8 expressions in LPS-stimulated BEAS-2B cells by OGE may be attributed to inhibiting activation of MAPKs and Akt and consequently suppressing nuclear translocation of NF-κB.

Cell Nucleus ; drug effects ; metabolism ; Cell Survival ; drug effects ; Cytosol ; drug effects ; metabolism ; Epithelial Cells ; drug effects ; enzymology ; metabolism ; Gene Expression Regulation ; drug effects ; Humans ; I-kappa B Proteins ; metabolism ; Interleukin-6 ; genetics ; metabolism ; Interleukin-8 ; genetics ; metabolism ; Intracellular Space ; drug effects ; metabolism ; Lipopolysaccharides ; pharmacology ; Mitogen-Activated Protein Kinases ; metabolism ; NF-KappaB Inhibitor alpha ; NF-kappa B ; metabolism ; Ocimum ; chemistry ; Phosphorylation ; drug effects ; Plant Extracts ; pharmacology ; Protein Transport ; drug effects ; Proto-Oncogene Proteins c-akt ; metabolism ; RNA, Messenger ; genetics ; metabolism ; Reactive Oxygen Species ; metabolism ; Respiratory System ; cytology ; Water