Extracellular traps released by neutrophils (neutrophil extracellular traps, NETs) are a double-edged sword, and understanding the mechanism of NET formation is of great significance for disease treatment. However, the short lifespan, the large individual differences, and the inability to perform gene editing render it difficult to decipher NET formation using neutrophils. It is necessary to find a model cell to replace neutrophils to study the mechanism of NET formation. In this study, we used different concentrations (0, 0.1, 1, and 10 μmol/L) of all-trans retinoic acid (ATRA) to differentiate HL-60 cells for different days (1, 3, 5, and 7 days). By detecting the cell viability and nuclear morphology of cells, we confirmed that HL-60 cells were differentiated to neutrophil-like cells (dHL-60) after treated with ATRA for at least 5 days. Using immunofluorescence staining to detect the formation of NETs, we demonstrated that dHL-60 cells differentiated for 5 days with 1 μmol/L ATRA could generate NETs comparable to those produced by neutrophils upon phorbol 12-myristate 13-acetate (PMA) stimulation, without histone H3 citrullination. Furthermore, the formation of NETs by dHL-60 cells were NADPH-dependent and PAD4-independent, consistent with neutrophils. Taken together, these observations suggest that dHL-60 cells differentiated with 1 μmol/L ATRA for 5 days can be used as a model cell for neutrophils to study the mechanism of NET formation.
Humans ; Extracellular Traps ; Tetradecanoylphorbol Acetate/pharmacology* ; Neutrophils ; HL-60 Cells ; Tretinoin/pharmacology*

This study was aimed to investigate the effects of arsenic trioxide (As2O3) combined with TPA on cell cycle, cell differentiation and apoptosis of K562 cell line, and their possible mechanisms. K562 cells were treated with 200 nmol/L TPA, 2 µmol/L As2O3 alone and 200 nmol/L TPA combined with 2 µmol/L As2O3. The proliferative inhibition rates were determined with CCK-8. Annexin V and agarose gel electrophoresis were adopted to detect apoptosis. Colony formation test was used to determine the colony-formation efficiency. Flow cytometry was used to detect the cell differentiation and cell cycle changes. Western blot was employed to detect the expression of P38 and p-P38 proteins. The results showed that combination treatment had synergistic effects on the proliferative inhibition and apoptosis, which were much higher than those treated alone. As2O3 could decrease the colony formation ability of K562 cells. The cells treated with both TPA and As2O3 expressed far more CD11b antigens compared with cells exposed to As2O3 alone. K562 cells treated with TPA were arrested in G1 phase compared with the control group, As2O3 increased the percentage of K562 cells in the G2 phase. The combination treatment increased the expression of p-P38 of K562 cells compared with the cells exposed As2O3 alone. It is concluded that TPA can enhance the effect of As2O3 on inducing apoptosis and adjusting cell cycle , which will expect to provide a new therapeutic program.
Apoptosis ; drug effects ; Arsenicals ; pharmacology ; Cell Cycle ; drug effects ; Drug Synergism ; Humans ; K562 Cells ; Oxides ; pharmacology ; Tetradecanoylphorbol Acetate ; pharmacology

OBJECTIVESince human mast cell is an important source of cytokines, it is of importance to understand the effects of anti-allergic drugs on cytokines modulation in mast cells. In the present study, we aimed at observing whether IL-4 could be released from human mast cell line (HMC-1) after the stimulation of PMA + A23187, and the effects of systemic glucocorticosteroid, dexamethasone, topical glucocorticosteroid, budesonide and H1 antagonist, desloratadine on IL-4 release and mRNA expression.

METHODSHMC-1 was stimulated with 25 ng/ml phorbol 12-myristate 13-acetate (PMA) and 2.5 x 10(-7) mol/L ionomycin (A23187) and cultured for 6 hours, 12 hours and 24 hours respectively in the presence or absence of 10(-6)-10(-10) mol/L concentrations of test drugs. Culture supernatants were collected and the levels of IL-4 were assayed by enzyme-linked immunosorbent assays (ELISA). The mRNA expression of IL-4 was measured by semiquantitative reverse transcription-polymerase chain reaction (RT-PCR).

RESULTSHMC-1 expressed IL-4 mRNA and the resulting protein production of IL-4 released after being stimulated with PMA plus A23187. Dexamethasone, budesonide and desloratadine had potent inhibitory effect on IL-4 release at any concentrations and time points, with significant deference (P < 0.05) compared to the control cells. The inhibitory effect did not show time-dependent and concentration-dependent manner. Desloratadine and budesonide showed neither up-regulatory nor down-regulatory effects on IL-4 mRNA expression at the test concentrations, however, desloratadine could down-regulate IL-4 mRNA expression.

CONCLUSIONSHMC-1 could express and produce IL4 after stimulation. Dexamethasone, budesonide and desloratadine all had inhibitory effects on IL-4 release from HMC-1. In addition, desloratadine could also inhibit the IL-4 mRNA expression.

Budesonide ; pharmacology ; Cell Line ; Dexamethasone ; pharmacology ; Humans ; Interleukin-4 ; biosynthesis ; Loratadine ; analogs & derivatives ; pharmacology ; Mast Cells ; drug effects ; metabolism ; Tetradecanoylphorbol Acetate ; pharmacology

Intravenous immunoglobulin (IVIG) is being increasingly used to treat numerous immune-mediated diseases. However, there is a paucity of knowledge on the specific mode of action of IVIG in vivo. In this study, the in vitro effects of IVIG on peripheral blood mononuclear cell (PBMC) proliferation using phytohemagglutinin (PHA), anti-CD3 monoclonal antibody (MAb), phorbol myristate acetate (PMA), or purified protein derivatives (PPD) have been analyzed. The PBMCs were obtained from more than 10 individual donors. In all cases, IVIG almost completely inhibited PBMC proliferation at concentration above 20 mg/mL except when used in conjunction with PMA. PHA-induced proliferation of PBMCs at concentrations ranging from 1 to 15 mg/mL did not show significant differences. Anti-CD3 MAb-induced proliferation showed dose-dependent inhibition at concentrations ranging from 1 to 10 mg/mL. Interestingly, PMA-induced proliferation of PBMCs showed a dose-dependent increase at the same concentration range. PPD-induced proliferation of PBMC at concentrations ranging from 1 to 10 mg/mL did not show any statistically significant differences. These results suggest that high dose IVIG may be necessary to immune modulation in vivo and IVIG has various effects on PBMCs proliferation in limited concentration in vitro.
Cell Division/drug effects ; Cells, Cultured ; Dose-Response Relationship, Drug ; Human ; Immunoglobulins, Intravenous/*pharmacology ; Leukocytes, Mononuclear/*drug effects/physiology ; Tetradecanoylphorbol Acetate/pharmacology

OBJECTIVEIn order to explore if power frequency magnetic field (PFMF) can act as cancer promoter or be synergistic with phorbol 12-myristate 13-acetate (TPA) in cancer promotion, the effects of 50 Hz MF on gap junction intercellular communication (GJIC) of astrocytes were observed.

METHODSFluorescence redistribution after photobleaching (FRAP) was adopted to observe the recovery of fluorescence intensity in the bleached cells thus to estimate intercellular communication by gap junction. Comparative fluorescence intensity recovery rate (CFIRR) was as evaluation index. The effects of 50 Hz MF alone or with TPA on GJIC of astrocytes were studied.

RESULTSAfter 3 ng/ml TPA treatment for 1 hour, M(d) of CFIRR was 4.53%/min, whereas that in the control group was 9.74%/min (H = 12.084, P < 0.005). After exposure to 0.8 and 1.6 mT magnetic field for 24 hours respectively, M(d) of CFIRR was 8.25%/min and 6.68%/min respectively, no significant difference from that of control (H = 32.617, P > 0.05). After exposure to 0.8 and 1.6 mT magnetic field for 23 hours then combined with 3 ng/ml TPA treatment for 1 hour, M(d) of CFIRR was 3.32%/min and 2.85%/min respectively, also no significant difference from that in the group treated with 3 ng/ml TPA alone (H = 2.589, P > 0.05).

CONCLUSION50 Hz MF (within 0 - 1.6 mT) alone could not inhibit GJIC of astrocytes; with TPA, could not enhance the inhibition of TPA on GJIC of astrocytes. But with MF intensity increasing, the inhibition of MF on GJIC showed elevated tendency.

Animals ; Astrocytes ; radiation effects ; ultrastructure ; Cell Communication ; radiation effects ; Electromagnetic Fields ; adverse effects ; Gap Junctions ; radiation effects ; Ornithine Decarboxylase ; metabolism ; Rats ; Rats, Sprague-Dawley ; Tetradecanoylphorbol Acetate ; pharmacology

OBJECTIVETo investigate whether the cellular gap junctional communication(GJIC) down-regulation in alveolar epithelial cells (CCL-64 cells) induced by silica-stimulated pulmonary alveolar macrophages (PAM) supernatant is related with the phosphorylation states of connexin 43(Cx43) protein.

METHODWestern-blot analysis was used to identify phosphorylated Cx43 species.

RESULTSWestern-blot analyses of SiO2- and phorbol 12-myristate 13-acetate(TPA)-treated CCL-64 cells showed the same phosphorylation states of Cx43 as the control group. There were no Cx43 protein in nucleus of CCL-64 cells.

CONCLUSIONThe inhibition on GJIC induced by SiO2 and TPA in CCL-64 cells may not be brought about by altering the phosphorylation states of Cx43.

Animals ; Cell Communication ; drug effects ; Cell Line ; Connexin 43 ; metabolism ; Gap Junctions ; drug effects ; Lung ; drug effects ; metabolism ; Mink ; Phosphorylation ; Silicon Dioxide ; toxicity ; Tetradecanoylphorbol Acetate ; pharmacology

BACKGROUNDNuclear factor kappaB (NF-kappaB) overactivation, requiring phosphorylation and degradation of its inhibitor IkappaBalpha, is the basis for chronicity of airway inflammation in asthma. Based on our previous plasmid pShuttle-IkappaBalpha, carrying an IkappaBalpha gene from human placenta, we optimized a novel IkappaBalpha mutant (IkappaBalphaM) gene, constructed and characterized its replication-deficient recombinant adenovirus (AdIkappaBalphaM), and tested whether AdIkappaBalphaM-mediated overexpression of IkappaBalphaM could inhibit the NF-kappaB activation in endothelial cells.

METHODSIkappaBalphaM gene (203 - 1003 bp) encoding 267 amino acids, acquired by site-directed deleting N-terminal phosphorylation sites of serine 32/36, was subcloned into the pShuttle and pGEM-T vectors for further polymerase chain reaction (PCR), restriction digestion, deoxyribonucleic acid (DNA) sequencing and homology analyses. Subsequent to inserting the expression unit of pShuttle-IkappaBalphaM, containing cytomegalovirus (CMV) promoter, IkappaBalphaM complementary DNA (cDNA) and polyadenylic acid (PolyA) signals, into the type 5 adenovirus (Ad5) vector, the resultant AdIkappaBalphaM was packaged in human embryonic kidney (HEK) 293 cells by cotransfection with lipofectamine. Western blot analysis and electrophoretic mobility shift assay were utilized to detect the AdIkappaBalphaM-mediated overexpression of IkappaBalphaM in HEK293 cells and its suppressive effect on phorbol 12-myristate 13-acetate (PMA)-induced NF-kappaB activation in human umbilical vein endothelial (ECV304) cells, respectively.

RESULTSThe relevant nucleotides and deduced amino acids of 801 bp IkappaBalphaM gene were consistent with those of IkappaBalpha gene (GenBank accession number: M69043). The titer of the prepared AdIkappaBalphaM was 4.0 x 10 (12) plaque-forming units (pfu)/L. Moreover, the IkappaBalphaM gene was overexpressed in HEK293 cells, and potently inhibited the PMA-induced NF-kappaB activation in ECV304 cells dose-dependently.

CONCLUSIONSAdIkappaBalphaM is a novel vector for both efficient transfer and specific overexpression of IkappaBalphaM gene, as well as potent inhibition of NF-kappaB activity, providing a promising strategy for gene therapy of asthma.

Adenoviridae ; genetics ; Cell Line ; Endothelial Cells ; metabolism ; Genetic Therapy ; Humans ; I-kappa B Proteins ; genetics ; Mutation ; NF-KappaB Inhibitor alpha ; NF-kappa B ; antagonists & inhibitors ; Tetradecanoylphorbol Acetate ; pharmacology

OBJECTIVETo investigate the effect of PKC phosphorylation sites mutation in JWA coding region on TPA-induced MCF-7 cell differentiation.

METHODSSite directed gene mutation was used to construct one or two PKC sites mutations in pEGFP-N1-JWA vectors, and transfected into MCF-7 cells by polyfect reagent, and cell differentiation was characterized by accumulation of lipid droplet as indicated by positive Oil-red-O staining of cells.

RESULTSAll these transfected cell lines, MCF-7-N1(transfected with pEGFP-N1 vector), MCF-7-JWA(transfected with pEGFP-N1-JWA vector), MCF-7-JWA-1(transfected with PKC site 1 mutation pEGFP-N1-JWA vector), MCF-7-JWA-2(transfected with PKC site 2 mutation pEGFP-N1-JWA vector), MCF-7-JWA-1+2 (transfected with both PKC site 1 and 2 mutation pEGFP-N1-JWA vector) were treated with 20 nmol/L TPA for 48 h, and the percentages of positive Oil-red-O staining of cells were 48%, 67%, 69%, 67% and 70% respectively. The percentages of cell differentiation in JWA containing vectors transfected cells treated with TPA were significantly higher those of MCF-7-N1 cells (vector only control). However there were no significant differences between mutated and unmutated cells.

CONCLUSIONJWA transfection enhanced MCF-7 cell differentiation induced by TPA significantly, and PKC sites mutation in JWA coding region has no obviously effect on TPA-induced MCF-7 cell differentiation.

Cell Differentiation ; drug effects ; Cell Line, Tumor ; Female ; Genetic Vectors ; Humans ; Mutagenesis, Site-Directed ; Phosphorylation ; Point Mutation ; Protein Kinase C ; genetics ; metabolism ; Tetradecanoylphorbol Acetate ; pharmacology ; Transfection

To investigate the effects of leptin on expression of acyl-coenzymeA: cholesterol acyl-transferases-1 (ACAT-1) in monocyte-macrophage differentiation, human monocytic cells (THP-1) were cultured in RPMI 1640 and made to differentiate into macrophages under the incubation with phorbol myristate acetate (PMA) for 48 h. The cells were divided into 4 groups according to different intervention factors as follows: MCs cultured in RPM11640 medium with 10% FBS for 48 h served as MC group (control group), MCs cultured in medium with serum-free RPM11640 containing 5% BSA, 100 nmol/L PMA for 48 h as MP group, MCs cultured in RPMI1640 medium with 10% FBS, 10 micromol/ml leptin for 48 h as leptin-MC group, and MCs cultured in medium with serum-free RPMI1640 containing 5% BSA. 100 nmol/L PMA, and 10 micromol/ml leptin for 48 h as leptin-MP group. Immunocytochemistry, reverse transcription polymerase chain reaction (RT-PCR) and Western blot were performed, respectively, to observe the effects of leptin on expression of ACAT-1 in the monocyte-macrophage differentiation. Our results showed that expression of ACAT-1 protein and mRNA in MP-group is two times that in MC-group (P<0.05), and the expression of ACAT-1 protein and mRNA increased by up to 4 folds in leptin-MP group-as compared with that of MC group (P<0.01). Thus, our results support the idea that expression of ACAT-1 increases more in cultured human macrophages than in monocytes, and leptin can significantly promote ACAT-1 expression. It was concluded that high expression of ACAT-1 may accelerate the development of human atherogenesis, and leptin might participate in atherogenesis by increasing expression of ACAT-1.
Atherosclerosis ; enzymology ; Cell Differentiation ; Cells, Cultured ; Humans ; Leptin ; pharmacology ; Macrophages ; cytology ; enzymology ; Monocytes ; cytology ; enzymology ; Sterol O-Acyltransferase ; biosynthesis ; genetics ; Tetradecanoylphorbol Acetate

OBJECTIVETo study the effects of extremely low frequency magnetic fields(ELF MF) on the amount and localization of connexin 43(Cx43) gap-junction protein in the Chinese hamster lung(CHL) cells, and to explore the mechanism of ELF MF suppression on gap-junctional intercellular communication(GJIC).

METHODSThe cells were irradiated for 24 h with 50 Hz sinusoidal magnetic field at 0.8 mT without or with 12-O-tetrade-canoylphorbol-3-acetate(TPA), 5 ng/ml for 1 h. The localization of Cx43 proteins were performed by indirect immunofluorescence histochemical analysis and detected by confocal microscopy. The second experiment was conducted to examine the quantity of Cx43 proteins level in nuclei or cytoplasm and detected by Western blotting analysis.

RESULTSThe cells exposed to TPA for 1 h displayed less bright labelled spots in the regions of intercellular junction than the normal cells. Most of Cx43 labelled spots occurred in the cytoplasm and aggregated near the nuclei. At the same time, the amount of Cx43 protein in cytoplasm were increased[(2.03 +/- 0.89) in ELF group, (2.43 +/- 0.82) in TPA group] as compared to normal control(1.04 +/- 0.17) (P < 0.01).

CONCLUSIONInhibition on GJIC function by ELF MF alone or combined with TPA may be related with the shift of Cx43 from the regions of intercellular junction to the cytoplasm.

Animals ; Cell Communication ; radiation effects ; Connexin 43 ; biosynthesis ; Cricetinae ; Cricetulus ; Cytoplasm ; metabolism ; Electromagnetic Fields ; adverse effects ; Gap Junctions ; radiation effects ; Lung ; metabolism ; radiation effects ; Tetradecanoylphorbol Acetate ; pharmacology