[Effect of epidermal growth factor on the expression of matrix metalloproteinase-9 and the signalling pathways involved in the trophoblast cell line JEG-3].

OBJECTIVE: To investigate the effect of epidermal growth factor (EGF) on the expression of Matrix metalloproteinase-9 (MMP-9) and the signalling pathways involved in the trophoblast cell line JEG-3. METHODS: The JEG-3 trophoblast cell line was used in this study. (1) JEG-3 cells were cultured with various concentrations of EGF (0, 1, 10, 20 ng/ml) for 24 hours and the expression of MMP-9 was tested by western blotting and reverse transcription PCR (RT-PCR). (2) Western blotting and RT-PCR were also used to investigate the expression of MMP-9 expression after incubation for 0, 4, 12 and 24 hours with EGF treatment (10 ng/ml) in JEG-3 cells. (3) According to the different added ingredients, JEG-3 cells were divided into some groups: control group (without EGF), EGF group (exposure to 10 ng/ml EGF), EGF+ inhibitors group (exposure to 10 ng/ml EGF+ 20 ng/ml SB203580 or exposure to 10 ng/ml EGF+ 10 ng/ml U0126), inhibitors group (exposure to 20 ng/ml SB203580 or exposure to 10 ng/ml U0126). Western blotting were used to investigate the expression levels of MMP-9, nuclear factor kappa B (NF-κB), p38MAPK, phospho-p38MAPK (p-p38MAPK), extracellular-signal regulated kinase (ERK) and phospho-ERK (p-ERK) protein in JEG-3 cells after incubation for 24 hours. RESULTS: (1) The profiles of MMP-9 mRNA were increased by various concentrations of EGF (0, 1, 10, 20 ng/ml) in JEG-3 cells after 24 h-culture. The expression of MMP-9 mRNA in JEG-3 cells exposure at 1 ng/ml of EGF (0.567±0.056), 10 ng/ml of EGF (1.392±0.133), 20 ng/ml of EGF (1.971±0.067) were significantly higher respectively (P<0.05), compared with 0 ng/ml of EGF treatment (0.166±0.015). Similarly, MMP-9 mRNAs were also increased with the increasing incubation time. Compared to EGF (10 ng/ml) stimulation for 0 h (0.253±0.044), the MMP-9 mRNA profiles were 0.470±0.026, 1.061±0.115, 1.453±0.180 for 4, 12 and 24 hours, respectively (P<0.05). (2) In accordance to the mRNA profiles, the expression of MMP-9 protein was also increased by different concentrations of EGF (0, 1, 10, 20 ng/ml) in JEG-3 cells after 24 h-culture. The abundance of MMP-9 protein in the three groups was 0.043±0.012, 0.085±0.008, 0.142±0.015, with a significantly higher expression, compared with 0 ng/ml of EGF treatment (0.004±0.001, P<0.05) respectively. Similarly, MMP-9 proteins were also increased with the increasing incubation time. Compared to EGF (10 ng/ml) stimulation for 0 h (0.030±0.009), the profiles of MMP-9 protein were 0.137±0.010, 0.240±0.010, 1.240±0.061 for 4, 12 and 24 hours, respectively (P<0.05). (3) Both p38MAPK and ERK signalling pathways were activated by EGF in JEG-3 cells. The expression of p-p38MAPK was significantly higher (without or with 10 ng/ml EGF, 234.1±4.1 vs. 260.9±2.5, P<0.05), however, the p38MAPK inhibitor SB203580 markedly suppressed the increase in p-p38MAPK content induced by EGF (227.9±2.4 vs. 260.9±2.5, P<0.05). Similarly, the expression of p-ERK was significantly higher with EGF treatment (812.2±3.5) vs. without EGF group (453.4±5.8) (P<0.05), while the ERK inhibitor U0126 significantly inhibited the increased p-ERK content in response to EGF treatment (71.0±1.2 vs. 812.2±3.5, P<0.05). (4) The p38MAPK inhibitor SB203580 significantly reduced the expression of EGF-induced MMP-9 (0.645±0.270 vs. 1.476±0.452, P<0.05) and NF-κB (0.530±0.026 vs. 0.959±0.017, P<0.05). (5) The ERK inhibitor U0126 also significantly reduced the expression of EGF-induced MMP-9 (0.623±0.030 vs. 2.112±0.056, P<0.05) and NF-κB (0.325±0.082 vs. 0.939±0.153, P<0.05). CONCLUSION: EGF induced the expression of MMP-9 in a time and dose-dependant manner in JEG-3 cells. EGF enhanced MMP-9 expression through the activation of p38MAPK and ERK signalling pathways in JEG-3 cells.

Dynamic development of parasitophorous vacuole of Eimeria tenella transfected with the yellow fluorescent protein gene fused to different signal sequences from apicomplexan parasites.

Intracellular stages of Eimeria tenella reside within a membrane-bound parasitophorous vacuole (PV). PVs of apicomplexan parasites like E. tenella play important roles in nutrient acquisition, multiplication, and evasion of host immune responses. Different signal sequences from apicomplexan parasites were investigated in the transfected E. tenella for their functions in targeting yellow fluorescent protein (YFP) to subcompartments and the dynamic development of the PV of E. tenella was studied. Two 5' terminal signal sequences derived from Toxoplasma gondii GRA8 protein and Plasmodium falciparum repetitive interspersed family protein, respectively, were confirmed to target YFP to the PVs of the transfected E. tenella, suggesting that signal sequences are functionally conserved among Apicomplexa. Three structurally different types of PVs were observed during the endogenous development of the transfected E. tenella in vitro. In addition, three subcompartments in the PV, namely, membranous extensions into the host cell cytosol, membranous extensions into the vacuolar lumen, and particle-like bodies, were detected during schizogony of the parasite.

Restriction enzyme-mediated transfection improved transfection efficiency in vitro in Apicomplexan parasite Eimeria tenella.

Genetic manipulation of Apicomplexan parasite Eimeria tenella is only in its earliest stages. In the current study, transfection of E. tenella was conducted by electroporating sporozoites along with linear or circular plasmid DNA, and with or without restriction enzyme. Transfection system containing both linear DNA and restriction enzyme resulted in a transfection efficiency of 2.2x10(-3)in vitro, which is 200-fold higher than that using circular plasmid DNA alone. In another transfection strategy, PCR amplicons of expression cassette, instead of whole plasmid DNA, were subjected to transfection, and it was also found successful. These results suggest that linear DNA and restriction enzyme together in the transfection system greatly improve the transfection efficiency of E. tenella. The high transfection efficiency makes possible the establishment of stable transfection in vivo; and the success of PCR-based, restriction enzyme-mediated transfection will further simplify the transfection process for E. tenella and other Apicomplexan parasites.