No abstract available.
Cytoskeleton/*ultrastructure ; Hepatocytes/*ultrastructure ; Humans ; Liver Diseases/*pathology

OBJECTIVETo explore the effects of cofilin on the actin cytoskeleton reorganization in osteoblasts induced by fluid shear stress.

METHODSFluid shear stress (1.2 Pa) was applied to osteoblasts for 0 (control group), 15, 30, 45, 60, 120 min in vitro. Cells were stained with fluorescein isothiocyanate (FITC)-phalloidin for fiber-actin, and confocal laser scanning microscope(CLSM) was used to observe the fluorescence of fiber-actin. Western blotting was used to detect the expression of the cofilin and the phospho-cofilin.

RESULTSActin filaments became organized into stress fibers that were thicker and more abundant than those in non-flowed cells. The fluorescence intensity (38.00 ± 6.88) of fiber-actin after 120 min (42.93 ± 6.41) loading it was 2.8 times as much as that in control group (15.41 ± 3.60, P < 0.05). Additionally, the level of phospho-cofilin protein was dramatically elevated after loading. Fluid shear stress induced an initial decrease of cofilin at 60 min. However, at 120 min cofilin (0.254 ± 0.026) increased to 1.5 times as much as that at 60 min (0.162 ± 0.004).

CONCLUSIONSThe results indicate that cofilin phosphorylation mediates fiber-actin reorganization in the osteoblasts induced by fluid shear stress.

Actin Cytoskeleton ; ultrastructure ; Actin Depolymerizing Factors ; biosynthesis ; Humans ; Osteoblasts ; ultrastructure ; Phosphorylation ; Stress, Mechanical

The objective of this study was to investigate the effect of cytomegalovirus (CMV) infection on actin and microfilament in human embryo fibroblast cells (HF) and to explore the possible relationship with CMV replication. The cell shape was observed by microscopy after the infection of CMV, RT-PCR assay was used to detect the mRNA expression of beta-actin gene, while Westen-blot was used to measure the level of beta-actin protein. CMV immediately early antigen (IE) in HF cells was analyzed by indirect immunofluorescence assay. Microfilament alteration was determined by cytoskeleton fluorescence probe. The results showed that CMV IE was observed in more than 95% of HF cells after infection, primarily located in nucleus. HF cells infected by CMV changed from thin shuttle shape to round and thick ball shape, even detached from wall. Beta-actin got a significant and gradual decreasing of mRNA level in time-dependent manner (P < 0.05). Compared with uninfected group, the expression of beta-actin protein decreased to (74.2 +/- 13.4)% at 96 hours after infection (P < 0.05). In infected HF cells, microfilaments were ruptured, arranged turbulently, as well as cells merged and fluorescence density of microfilament obviously reduced. It is concluded that cytomegalovirus can induce alteration of actin and microfilament, which may be helpful for CMV to infect, replicate and reactivate in host cells.
Actin Cytoskeleton ; metabolism ; ultrastructure ; Actins ; metabolism ; Cell Line ; Cytomegalovirus Infections ; metabolism ; pathology ; Fibroblasts ; pathology ; ultrastructure ; virology ; Humans

BACKGROUNDTo investigate the differential expression levels of thymosin beta 10 (T beta 10) and the corresponding changes of actin filament organization in human tumor cell lines with different metastatic potential.

METHODSFour groups of nine human tumor cell lines with different metastatic potential were analyzed for the amount of T beta 10 mRNAs by Northern blot and for their peptide expression levels by immunohistochemistry. The filamentous actin (F-actin) was observed by staining of TRITC-phalloidin to detect changes in actin organization.

RESULTSIn comparison with non-/weakly metastatic counterparts, T beta 10 was upregulated in highly metastatic human lung cancer, malignant melanoma and breast cancer cell lines. Staining of TRITC-phalloidin revealed less actin bundles, a fuzzy network of shorter filaments and some F-actin aggregates in the highly metastatic tumor cells. Meanwhile, the actin filaments were robust and orderly arranged in the non-/weakly metastatic cancer cell lines.

CONCLUSIONT beta 10 levels correlate positively with the metastatic capacity in human tumors currently examined. The increasing metastatic potential of tumor cells is accompanied by a loss of F-actin, poorly arranged actin skeleton organizations and presence of F-actin aggregates. There is a consistent correlation between the elevated T beta 10 expression and the disrupted actin skeleton.

Actin Cytoskeleton ; ultrastructure ; Blotting, Northern ; Cell Line, Tumor ; Humans ; Immunohistochemistry ; Neoplasm Metastasis ; genetics ; ultrastructure ; RNA, Messenger ; analysis ; Thymosin ; analysis

The aim of our study was to determine the effects of energy controllable steep pulse (ECSP) on the cytoskeleton of human ovarian cancer cells SKOV3. SKOV3 cells were divided into five groups under ECSP treatment with different parameters (frequency, pulse duration, peak value of voltage). The positive control group included SKOV3 cells treated with volchicine; the negative control group included SKOV3 cells subjected to sham-lightning stroke. Rhodamine-phalloidine was used to label microfilament directly. After using immunofluorescence to label microbules, we observed them by means of Confocal Laser Scanning Microscope. Making specimen and using electronmicroscope, we observed the ultramicrostructure of cystoskeleton. The results showed that ECSP-treated-SKOV3 cells lost their normal cystoskeleton network structure. There were obvious microfilament disaggregation, diffused skeleton protein, and disappearance of cystoskeleton network structure. Also noticeable were microbule disaggregation, reduction of pseudopod, obvious microfilament disaggregation, permutation disorder and structure disappearance. Moreover, this effect bears a direct relation with dosage.
Cell Line, Tumor ; Cytoskeleton ; ultrastructure ; Electric Conductivity ; Electromagnetic Fields ; Electroporation ; Female ; Humans ; Ovarian Neoplasms ; pathology ; Pulse

This study was purposed to investigate the change of biological characteristics of HL-60 cells with high tumorigenicity transplanted through repeated passages into nude mice and to explore the tumorigenic mechanisms of the cell line. The human highly tumorigenic leukemia cell line HL-60 model in nude mice were established by serial passages in vivo and in vitro, and their biological features were compared. The trypan blue staining assay was used to detect the cell growth, the flow cytometry was used to analyze the cell cycle, the transmission electron microscopy and laser scanning confocal microscopy were used to observe the cell ultrastructures and cell fluorescence level respectively. The results indicated that the cell growth velocity was quickened, cell doubling time was shortened in high tumorigenic leukemia cell line HL-60; the cell count in S phase increased; the amount of mitochondria in HL-60 cells obviously decreased, furthermore the dilation of interspace, decrease of the number of ridges, vacuolation of mitochondria, significant reduction of fluorescence level in microfilament and enhancement of cell cloning efficacy were observed. It is concluded that the high tumorigenicity of HL-60 cells multiple-passaged in nude mice is associated with enhancement of proliferative ability, changes of number and structure of mitochondria in HL-60 cells, and alteration of microfilament in cytoskeleton.
Actin Cytoskeleton ; ultrastructure ; Animals ; Cell Cycle ; HL-60 Cells ; cytology ; ultrastructure ; Humans ; Mice ; Mice, Inbred BALB C ; Mice, Nude ; Mitochondria ; ultrastructure ; Neoplasm Transplantation

OBJECTIVETo investigate the effect of cytomegalovirus (CMV) infection on actin and microfilament in human embryo fibroblast cells (HF) and its relationship with CMV replication.

METHODSCell morphology was observed after the infection of CMV. Western-blot was used to measure the expression levels of beta-actin, G-actin and F-actin proteins. CMV immediately early antigen (CMV IE) in HF cells was analyzed by indirect immunofluorescence assay. Microfilament alteration was determined by cytoskeleton fluorescence probe.

RESULTCMV IE was demonstrated in more than 95% of HF cells after infection, which was primarily located in nucleus. The shape of HF cells changed from thin shuttle like to round and thick ball like, even escaping from wall after infection by CMV. Compared with control group, the expression of G-actin protein increased at 24 h of CMV infection (0.941 +/-0.061 compared with 0.714 +/-0.119, P <0.05), then decreased at 72 h, 96 h respectively(0.218 +/-.035, 0.230 +/-0.055 compared with 0.714 +/-0.119, P <0.05). The levels of F-actin in infected cells gradually decreased at 24 h, 72 h and 96 h compared with control HF cells (0.256 +/-0.021, 0.127 +/-0.032, 0.026 +/-0.008 compared with 0.373 +/-0.050, P<0.05). In infected HF cells, microfilaments were found ruptured, arranged turbulently. Cells fused and fluorescence density of microfilament markedly reduced.

CONCLUSIONCytomegalovirus can induce alteration of actins and microfilament, which may be associated with its infection, replication and reactivity in host cells.

Actin Cytoskeleton ; metabolism ; Actins ; biosynthesis ; genetics ; Antigens, Viral ; analysis ; Cells, Cultured ; Cytomegalovirus ; Cytoskeleton ; metabolism ; Embryo, Mammalian ; Fibroblasts ; metabolism ; ultrastructure ; virology ; Humans ; Immediate-Early Proteins ; analysis

OBJECTIVETo investigate the influence of CO(2) and He insufflation administered at different pressures on the migration and cytoskeleton of cultured human gastric cancer cells.

METHODSThe cultured gastric cancer cells MKN-45 were exposed to a CO(2) or He environment maintained at different pressures (12, 15 mm Hg). After 0, 2, 4, 6, 8 hours exposure to CO(2) or He environment, pH of the MKN-45 cells culture media was measured with blood gas analysis. The cell migration was detected with Transwell technology. The cell cytoskeleton was observed with laser confocal microscope.

RESULTSThe media pH was acid after exposure to CO(2) environment, while it was basic in the He group. The number of cells passing millipore in 12 mm Hg CO(2) or He insufflation pressure were not significantly different with control group (P>0.05), however in 15 mm Hg pressure CO(2) group, it was significantly decreased as compared to control group (P<0.01). The microfilament and microtubule in gastric cancer cell were ambiguous in 15 mm Hg pressure CO(2) group.

CONCLUSIONSThere are no obvious effects on the migration and cytoskeleton of MKN-45 cells under 12 mm Hg CO(2) insufflation pressure. The migration and cytoskeleton of MKN-45 cells can be inhibited in 15 mm Hg CO(2) pneumoperitoneum environment.

Carbon Dioxide ; administration & dosage ; Cell Line, Tumor ; Cell Movement ; Cell Survival ; Cytoskeleton ; Humans ; Pneumoperitoneum, Artificial ; Pressure ; Stomach Neoplasms ; ultrastructure

BACKGROUNDVibrio vulnificus (Vv) is an estuarine bacterium that can cause primary septicemia as well as serious wound infections. However, little is known about the mechanisms by which Vv infects dendritic cells (DCs) and its effects on cytoskeleton. In this study, we aimed to investigate the invasion, internalization, and the organelles damage of the cultured dendritic cells (a DC 2.4 strain) during Vv infection.

METHODSThe study model was the cultured DCs infected by a Vv 1.758 strain. Electron microscopy was used to observe the localization of bacteria at the different time points of infection, cell morphology, and the process of organelles changes. The cytoskeleton structure including the microfilaments and the microtubules rearrangement was examined under a fluorescence microscope.

RESULTSThe Vv were pinocytosised into the DC cells through double-sides, and localized at 1 - 2 mm of the inner side membrane. It took 1.3, 1.9, and 3.4 hours to reach the infection ratio of 25%, 50%, and 75%, respectively. Using electron microscopy, the DCs had been observed to have developed chromatin aggregation within 4.0 hours, and significant cytoskeleton structure disruption was noted within 6.0 hours.

CONCLUSIONThe high lethality of Vv infection may be associated with the direct disruption of the DCs cytoskeleton structure.

Animals ; Apoptosis ; physiology ; Cells, Cultured ; Cytoskeleton ; metabolism ; ultrastructure ; DNA Fragmentation ; Dendritic Cells ; metabolism ; microbiology ; ultrastructure ; Mice ; Microscopy, Electron ; Microscopy, Electron, Transmission ; Vibrio Infections ; metabolism ; Vibrio vulnificus ; pathogenicity

This study sought to detect the effect of Fascin-1 expression on the cytoskeleton and immigration of laryngeal squamous carcinoma cell. In the experiment, Fascin-1 expression in Hep-2 cells was inhibited by small interfering RNA. The cytoskeleton of Hep-2 cells was observed with the use of laser scanning confocal fluorescence microscope. Millicell insert was applied to detect the immigration of Hep-2 cells in vitro. The results showed that the integrity of cytoskeleton in Hep-2 cells was broken with the down-regulation of Fascin-1 expression and the immigration ability was decreased significantly (P < 0.05). The inhibiting ratio of cell immigration was 44.6 +/- 6.3%. In conclusion, inhibition of Fascin-1 expression in Hep-2 cells could break the integrity of cytoskeleton and decrease the ability of cellular immigration.
Carcinoma, Squamous Cell ; metabolism ; ultrastructure ; Carrier Proteins ; genetics ; metabolism ; Cell Line, Tumor ; Cell Movement ; Cytoskeleton ; metabolism ; ultrastructure ; Down-Regulation ; Humans ; Laryngeal Neoplasms ; metabolism ; ultrastructure ; Microfilament Proteins ; genetics ; metabolism ; RNA, Small Interfering ; genetics