C.K. Park

Exogenous DNA uptake of boar spermatozoa by a magnetic nanoparticle vector system.

The sperm-mediated gene transfer method is applicable to transgenesis in many species that use spermatozoa for reproduction recently, which has been shown various results. In the current study, we show that transgenic porcine embryos can be efficiently produced by employing a simple transfection method that uses magnetic nanoparticles (MNPs). The complexes formed between plasmid DNA and MNPs were bounded on ejaculated boar spermatozoa at a higher efficiency compared to methods using DNA alone or lipofection. Using confocal microscopy, rhodamine fluorophore-labelled MNPs were detected on external surfaces of the spermatozoa membrane, which were bounded on zona pellucida of in vitro maturated oocyte during in vitro fertilization. Electron microscopy revealed that clusters of MNPs were detected in inside of plasma membrane and nucleus of the spermatozoa head. Additionally, we found that magnetofected boar spermatozoa could be fertilized with oocytes in vitro and that the resulting gene of green fluorescent protein was detected in fertilized eggs by genomic PCR analysis. Taken together, these results suggest that MNPs can be used to efficiently introduce a transgene into embryo via spermatozoa.

Real-time in vivo bioluminescence imaging of lentiviral vector-mediated gene transfer in mouse testis.

Although much research has focused on transferring exogenous genes into living mouse testis to investigate specific gene functions in spermatogenic, Sertoli, and Leydig cells, relatively little is known regarding real-time gene expression in vivo. In this study, we constructed a bicistronic lentiviral vector (LV) encoding firefly luciferase and enhanced green fluorescence protein (EGFP); this was a highly efficient in vivo gene transfer tool. After microinjecting LV into the seminiferous tubules the ICR mouse testis, we detected luciferase and EGFP expression in vivo and ex vivo in the injected tubules using bioluminescence imaging (BLI) with the IVIS-200 system and fibered confocal fluorescence microscopy (CellViZio), respectively. In addition, with an in vivo BLI system, luciferase expression in the testis was detected for approximately 3 mo. Furthermore, EGFP expression in seminiferous tubules was confirmed in excised testes via three-dimensional fluorescent imaging with a confocal laser-scanning microscope. With immunostaining, EGFP expression was confirmed in several male germ cell types in the seminiferous tubules, as well as in Sertoli and Leydig cells. In conclusion, we demonstrated that real-time in vivo BLI analysis can be used to noninvasively (in vivo) monitor long-term luciferase expression in mouse testis, and we verified that EGFP expression is localized in seminiferous tubules after bicistronic LV-mediated gene transfer into mouse testes. Furthermore, we anticipate the future use of in vivo BLI technology for real-time study of specific genes involved in spermatogenesis.

Cell-type specificity of interleukins 1α and 1β on prostaglandin and plasminogen activator production in bovine endometrial cells.

Interleukin (IL)-1alpha is a potent stimulator of prostaglandin production in bovine endometrium, and IL-1 affects plasminogen activator (PA) activity in several types of cells. In this study, we determined the effects of IL-1alpha and IL-1beta on production of the prostaglandins PGF(2alpha) and PGE(2) and on PA activity in cultured bovine endometrial epithelial and stromal cells. We also determined the effects of PGE(2) and PGF(2alpha) on PA activity in these cells. Finally, we used RT-PCR to examine the expression of IL-1alpha, IL-1beta, and IL-1 receptor type 1 (IL-1R) mRNA in cultured bovine endometrial cells. This analysis revealed that IL-1alpha mRNA was present only in the stromal cells, whereas IL-1beta and IL-1R mRNAs were present in both cell types. When cultured cells were exposed to IL-1alpha and IL-1beta at concentrations ranging from 0.006 to 3 nM for 24h, IL-1alpha and IL-1beta were found to dose-dependently stimulate PGE(2) and PGF(2alpha) production in stromal cells (P<0.05) but not in epithelial cells. On the other hand, exposure to IL-1alpha and IL-1beta dose-dependently increased PA activity in the epithelial cells, whereas neither stimulated PA production in the stromal cells. When cells were exposed to IL-1alpha and IL-1beta at concentrations ranging from 0.06 to 3 nM for 24h, the two IL-1s differed in their effects on both PGE(2) and PGF(2alpha) production in stromal cells and had significantly differed in their effects on PA activity in epithelial cells. Exposure to PGE(2) and PGF(2alpha) did not affect PA activity in either stromal or epithelial cells (P>0.05). Taken together, these results suggest the possibility that both IL-1alpha and IL-1beta are produced by the stromal cells, that IL-1beta is produced by the epithelial cells, and that IL-1alpha is a far more potent stimulator than IL-1beta of prostaglandin and PA production in cultured bovine endometrial epithelial and stromal cells.

Microtubule distribution in somatic cell nuclear transfer bovine embryos following control of nuclear remodeling type

This study was conducted to evaluate the microtubule distribution following control of nuclear remodeling by treatment of bovine somatic cell nuclear transfer (SCNT) embryos with caffeine or roscovitine. Bovine somatic cells were fused to enucleated oocytes treated with either 5 mM caffeine or 150 µM roscovitine to control the type of nuclear remodeling. The proportion of embryos that underwent premature chromosome condensation (PCC) was increased by caffeine treatment but was reduced by roscovitine treatment (p < 0.05). The microtubule organization was examined by immunostaining β- and γ-tubulins at 15 min, 3 h, and 20 h of fusion using laser scanning confocal microscopy. The γ-tubulin foci inherited from the donor centrosome were observed in most of the SCNT embryos at 15 min of fusion (91.3%) and most of them did not disappear until 3 h after fusion, regardless of treatment (82.9-87.2%). A significantly high proportion of embryos showing an abnormal chromosome or microtubule distribution was observed in the roscovitine-treated group (40.0%, p < 0.05) compared to the caffeine-treated group (22.1%). In conclusion, PCC is a favorable condition for the normal organization of microtubules, and inhibition of PCC can cause abnormal mitotic division of bovine SCNT embryos by causing microtubule dysfunction.

Stimulation of plasminogen activator activity by free radicals in boar spermatozoa

Plasminogen activators (PAs), commonly found on the membrane of spermatozoa, convert plasminogen into plasmin and may participate in mammalian fertilization. Correlations have been reported between reactive oxygen species (ROS) and spermatozoa function, although the relationship between PA activity and ROS is unknown. We investigated the effects of ROS on PA activity. We used an in vitro model of free radical generation whereby boar spermatozoa were preincubated in xanthine and xanthine oxidase (X-XO) and PA activity was then measured. The acrosome reaction of boar spermatozoa was significantly promoted by 100 mU/mL plasmin (P<0.01), similar to levels achieved when stimulated with the positive calcium (2 mM) control. The addition of plasminogen to the fertilization medium significantly promoted both spermatozoa binding (157.5+/-14.0 spermatozoa/oocyte) and the percentage of oocytes with a male pronucleus (74.5+/-6.4%) compared with control (98.4+/-21.8 spermatozoa/oocyte and 51.4+/-5.3%, respectively; P<0.05). The acrosome reactions of spermatozoa were significantly higher when incubated with calcium (2 mM; 60.2+/-2.7%), calcium (2 mM)+EDTA (6 mM; 29.4+/-4.2%), sodium nitroprusside (0.1 microM; 38.0+/-4.2%), H(2)O(2) (100 microM; 56.0+/-3.0%), and X-XO (0.5 mM and 0.05 U/mL, respectively; 31.8+/-3.7%) compared with non-capacitation medium as control (19.0+/-2.7%; P<0.05). However, when spermatozoa were incubated with only X-XO, PA activity was significantly higher than with other treatments (P<0.05). Moreover, the addition of the antioxidant superoxide dismutase to the X-XO system significantly blocked the PA activity of spermatozoa (P<0.05). The PA activity of spermatozoa treated with X-XO was significantly reduced by the addition of MEK inhibitor (55.2+/-5.6 ng/mL) and p38 inhibitor (57.4+/-2.7 ng/mL), but not PI3K inhibitor, compared to the control (X-XO; 68.0+/-5.8 ng/mL; P<0.05). The induction of PA activity in boar spermatozoa by free radical generation suggests the PA/plasmin system plays a role in mammalian fertilization.

Effects of Culture Dimensions on Maintenance of Porcine Inner Cell Mass-Derived Cell Self-Renewal

Despite the fact that porcine embryonic stem cells (ESCs) are a practical study tool, in vitro long-term maintenance of these cells is difficult in a two-dimensional (2D) microenvironment using cellular niche or extracellular matrix proteins. However, a three-dimensional (3D) microenvironment, similar to that enclosing the inner cell mass of the blastocyst, may improve in vitro maintenance of self-renewal. Accordingly, as a first step toward constructing a 3D microenvironment optimized to maintain porcine ESC self-renewal, we investigated different culture dimensions for porcine ICM-derived cells to enhance the maintenance of self-renewal. Porcine ICM-derived cells were cultured in agarose-based 3D hydrogel with self-renewal-friendly mechanics and in 2D culture plates with or without feeder cells. Subsequently, the effects of the 3D microenvironment on maintenance of self-renewal were identified by analyzing colony formation and morphology, alkaline phosphatase (AP) activity, and transcriptional and translational regulation of self-renewal-related genes. The 3D microenvironment using a 1.5% (w/v) agarose-based 3D hydrogel resulted in significantly more colonies with stereoscopic morphology, significantly improved AP activity, and increased protein expression of self-renewal-related genes compared to those in the 2D microenvironment. These results demonstrate that self-renewal of porcine ICM-derived cells can be maintained more effectively in a 3D microenvironment than in a 2D microenvironment. These results will help develop novel culture systems for ICM-derived cells derived from diverse species, which will contribute to stimulating basic and applicable studies related to ESCs.

Beneficial effects of silymarin against nitric oxide-induced oxidative stress on cell characteristics of bovine oviduct epithelial cell and developmental ability of bovine IVF embryos

The antioxidative effects of silymarin were examined against nitric oxide-induced oxidative stress on cell characteristics of bovine oviduct epithelial cell (BOEC) and developmental rates of bovine in vitro fertilisation (IVF) embryos. The cell viability and morphology in BOEC which were treated with sodium nitroprusside (SNP) declined, as concentrations of SNP increase. The additions of silymarin 50, 100 and 200 µM into SNP 1000 µM increased the cell viability inhibited by SNP 1000 µM alone, but addition of silymarin 500 µM into SNP 1000 µM group did not recover the inhibitory effect of SNP 1000 µM (p<0.05). The levels of malondialdehyde (MDA), as the indicator of lipid peroxidation (LPO) in the treatments of SNPs increased with dose-dependant manners (p<0.05), whereas additions of silymarin 50, 100 and 200 µM into SNP 1000 µM significantly decreased MDA levels by 1.6, 1.4 and 1.3 folds of control (p<0.05). Antioxidant and Bcl-2 genes were expressed in control or SNP 1000 µM plus silymarin 200 µM treatment group, whereas pro-apoptotic genes (caspase-3 and Bax) were expressed only in SNP treatment groups. When bovine IVF embryos were co-cultured with BOEC supplemented with silymarin in the presence or absence of SNP, the development ability to blastocyst in 200 µM of silymarin alone was the highest among all treatments. These results suggest that silymarin has positive effects on cell characteristics such as viability, morphology and LPO of BOEC, and the increase of bovine IVF embryo development rate might be through antioxidative and anti-apoptotic actions.

Effects of Endocrine Disruptors (NP, DBP and BPA) on Sperm Characteristics and Development of IVF Embryos in Pig

This study was to examine single or combined in vitro effects of environmental endocrine disruptors on boar sperm characteristics, oxidative stress damage in sperm and development of porcine IVF embryos. Addition of various concentration of NP (10, 20, 30μM), DBP (10, 50, 100 μM) and BPA (1, 5 or 10 μg/ml) on boar sperm characteristics such as percentages of sperm motility, viability, membrane integrity and mitochondrial activity were dose-dependently decreased within 3, 6 or 9 hr incubation period (p<0.05). The overall detrimental effects increased with incubation time increasement. NP, DBP and BPA showed the detrimental effects on sperm membrane and mitochondria of energy production organelles affecting cell viability with the dependancy of dose and incubation time. In combination effects, NP (10 μM) + DBP (10 μM) significantly decreased boar general sperm characteristics for 3 or 6 hr incubation period compared with control (p<0.05). When both of NP and DBP concentrations (NP; 30 μM, DBP; 100 μM) increase, the detrimental effects on sperm characteristics were larger than those of low concentration combination (p<0.05). The inhibitory effects of NP (30 μM) + BPA (10 μg/ml) on sperm characteristics were larger than those of NP (10 μM) + BPA (1 μg/ml) (p<0.05). DBP (100 μM) + BPA (10 μg/ml) decreased sperm characteristics compared with the low concentration combination (DBP 10 μM + BPA 1 μg/ml, p<0.05). This result indicates the detrimental effects of both chemicals on sperm characteristics were dose dependent. Addition of NP (30 μM) + DBP (100 μM), NP (30 μM) + BPA (10 μg/ml), DBP (10 μM) + BPA (1 μg/ml) or DBP (100 μM) +B PA (10μg/ml) significantly increased lipid peroxidation for 3 or 6 hr incubation period (p<0.05) compared with no addition control. NP (≥ 20 μM) decreased the percentages of IVF embryo development from morulae and blastocyst stages (p<0.05) and its detrimental effects were dose-dependant. BPA 0, 1, 5 or 10 μg/ml decreased significantly and dose-dependently the percentage of morulae plus and blastocysts (p<0.05). Combinations of DBP (100 μM) plus NP (30 μM) and DBP (100 μM) plus BPA (10 μg/ml) did not affect on morulae and blastocyst development, but NP (30 μM) plus BPA (10 μg/ml) has significant detrimental effect on embryo development at these stages (p<0.05). These overall results indicate that the partial detrimental effects on boar sperm characteristics and embryo development by NP, DBP, BPA or the combination of these chemicals might be due to the increasement of lipid peroxidation and free radical formation in the cell and there were no specific interaction effects on boar sperm and embryo degeneration among the combined treatments.