Analysis of stage-specific expression of the toll-like receptor family in the porcine endometrium throughout the estrous cycle and pregnancy.

Toll-like receptors (TLRs) play critical roles in innate immunity by regulating antimicrobial responses in mucosal tissues. The expression and function of TLRs in female reproductive tissues have been studied in several species, but the expression and function of TLRs and MYD88, an adaptor molecule in the TLR signaling pathway, at the maternal-conceptus interface are not well understood in pigs. Thus, we determined the expression of TLR1 - TLR10 and MYD88 in the endometrium, conceptus, and chorioallantoic tissues of pigs. TLR1 - TLR10 and MYD88 mRNAs were expressed in the endometrium during the estrous cycle and pregnancy in a stage-dependent manner. TLR and MYD88 mRNAs were also detected in early stage conceptuses and chorioallantoic tissues from Day 30 to term pregnancy. The expression of TLR2, TLR4, TLR5, and TLR7 was localized to epithelial and stromal cells in endometrial and chorioallantoic tissues. Increasing doses of P4, but not E2, induced the expression of TLR4, TLR5, TLR6, TLR7, and TLR8, while interferon-γ increased the expression of TLR2 and TLR7 in endometrial explant tissues. Expression of TLR3, TLR5, TLR6, TLR7, and MYD88 was higher in the endometrium with somatic cell nucleus transfer-derived conceptuses than conceptuses derived from natural mating on Day 12. These results indicate that the expression of TLR1 - TLR10 and MYD88 is dynamically regulated at the maternal-conceptus interface in pigs, suggesting that TLRs expressed in the endometrium and the placenta may play a critical role in regulating mucosal immune responses to support the establishment and maintenance of pregnancy.

Effects of Trichostatin A on In vitro Development of Porcine Embryos Derived from Somatic Cell Nuclear Transfer.

Many different approaches have been developed to improve the efficiency of animal cloning by somatic cell nuclear transfer (SCNT), one of which is to modify histone acetylation levels using histone deacetylase inhibitors (HDACi) such as trichostatin A (TSA). In the present study, we examined the effect of TSA on in vitro development of porcine embryos derived from SCNT. We found that TSA treatment (50 nM) for 24 h following oocyte activation improved blastocyst formation rates (to 22.0%) compared with 8.9% in the non-treatment group and total cell number of the blastocysts for determining embryo quality also increased significantly (88.9→114.4). Changes in histone acetylation levels as a result of TSA treatment were examined using indirect immunofluorescence and confocal microscopy scanning. Results showed that the histone acetylation level in TSA-treated embryos was higher than that in controls at both acetylated histone H3 lysine 9 (AcH3K9) and acetylated histone H4 lysine 12 (AcH4K12). Next, we compared the expression patterns of seven genes (OCT4, ID1; the pluripotent genes, H19, NNAT, PEG1; the imprinting genes, cytokeratin 8 and 18; the trophoblast marker genes). The SCNT blastocysts both with and without TSA treatment showed lower levels of OCT4, ID1, cytokeratin 8 and 18 than those of the in vivo blastocysts. In the case of the imprinting genes H19 and NNAT, except PEG1, the SCNT blastocysts both with and without TSA treatment showed higher levels than those of the in vivo blastocysts. Although the gene expression patterns between cloned blastocysts and their in vivo counterparts were different regardless of TSA treatment, it appears that several genes in NT blastocysts after TSA treatment showed a slight tendency toward expression patterns of in vivo blastocysts. Our results suggest that TSA treatment may improve preimplantation porcine embryo development following SCNT.

Successful cloning of coyotes through interspecies somatic cell nuclear transfer using domestic dog oocytes.

Interspecies somatic cell nuclear transfer (iSCNT) is an emerging assisted reproductive technology (ART) for preserving Nature's diversity. The scarcity of oocytes from some species makes utilisation of readily available oocytes inevitable. In the present study, we describe the successful cloning of coyotes (Canis latrans) through iSCNT using oocytes from domestic dogs (Canis lupus familiaris or dingo). Transfer of 320 interspecies-reconstructed embryos into 22 domestic dog recipients resulted in six pregnancies, from which eight viable offspring were delivered. Fusion rate and cloning efficiency during iSCNT cloning of coyotes were not significantly different from those observed during intraspecies cloning of domestic dogs. Using neonatal fibroblasts as donor cells significantly improved the cloning efficiency compared with cloning using adult fibroblast donor cells (P<0.05). The use of domestic dog oocytes in the cloning of coyotes in the present study holds promise for cloning other endangered species in the Canidae family using similar techniques. However, there are still limitations of the iSCNT technology, as demonstrated by births of morphologically abnormal coyotes and the clones' inheritance of maternal domestic dog mitochondrial DNA.

Cloning missy: obtaining multiple offspring of a specific canine genotype by somatic cell nuclear transfer.

The present study was undertaken to evaluate two activation methods for somatic cell nuclear transfer (SCNT), namely, fusion and simultaneous activation (FSA, fusion medium contains calcium), versus fusion followed by chemical activation (F+CA, fusion medium does not contain calcium), and to evaluate the effects of parity of recipient dogs on the success of SCNT. Oocytes retrieved from outbred dogs were reconstructed with adult somatic cells collected from an 11-year-old female dog named Missy. In the FSA method, oocytes were fused and activated at the same time using two DC pulses of 1.75 kV/cm for 15 microsec. In the F+CA method, oocytes were fused with two DC pulses of 1.75 kV/cm for 15 microsec, and then activated 1 h after fusion by 10 microM calcium ionophore for 4 m and cultured for 4 h in 1.9 mM 6-dimethylaminopurine for postactivation. Activation method had a significant impact on the production efficiency of cloned dogs. There was a significant difference in full-term pregnancy rate and percentage of live puppies between the two methods (6.3% and 38.5% for FSA and F+CA, respectively). In our study, four out of five live offspring produced by F+CA survived versus FSA, which did not result in any surviving puppies. Overall, as few as 14 dogs and 54 reconstructed embryos were needed to produce a cloned puppy. In addition, the parity of recipient bitches had no effect on the success of SCNT in canine species. Both the nullipara and multipara bitches produced live puppies following SCNT-ET.

Production of cloned dogs by decreasing the interval between fusion and activation during somatic cell nuclear transfer.

To improve the efficiency of somatic cell nuclear transfer (SCNT) in dogs, we evaluated whether or not the interval between fusion and activation affects the success rate of SCNT. Oocytes retrieved from outbred dogs were reconstructed with adult somatic cells from a male or female Golden Retriever. In total, 151 and 225 reconstructed oocytes were transferred to 9 and 14 naturally synchronized surrogates for male and female donor cells, respectively. Chromosomal morphology was evaluated in 12 oocytes held for an interval of 2 hr between fusion and activation and 14 oocytes held for an interval of 4 hr. Three hundred seventy-six and 288 embryos were transferred to 23 and 16 surrogates for the 2 and 4 hr interval groups, respectively. Both the male (two pregnant surrogates gave birth to three puppies) and female (one pregnant surrogate gave birth to one puppy) donor cells gave birth to live puppies (P > 0.05). In the 2 hr group, significantly more reconstructed oocytes showed condensed, metaphase-like chromosomes compared to the 4 hr group (P < 0.05). A significantly higher pregnancy rate and a greater number of live born puppies were observed in the 2 hr group (13.0% and 1.1%, respectively) compared to the 4 hr group (0%) (P < 0.05). In total, three surrogate dogs carried pregnancies to term and four puppies were born. These results demonstrate that decreasing the interval between fusion and activation increases the success rate of clone production and pregnancy. These results may increase the overall efficiency of SCNT in the canine family.

Birth of Beagle dogs by somatic cell nuclear transfer.

The present study was undertaken to evaluate two enucleation methods for somatic cell nuclear transfer (SCNT), and to standardize the optimum number of embryos for transfer to each recipient for canines. Oocytes retrieved from outbreed dogs were reconstructed with adult somatic cells from a male Beagle dog. A total of 134 or 267 oocytes were enucleated either by aspiration or squeezing method, fused with two DC pulses of 1.75 kV/cm for 15 micros electrical stimulation, chemically activated after 1h of fusion using 10 microM calcium ionophore for 4 min and cultured 4h in 1.9 mM 6-dimethylaminopurine. Finally, 103 or 214 embryos for aspiration or squeezing method were transferred to 6 or 11 naturally synchronized recipients, respectively. A total of 53, 317 and 342 embryos were transferred to 7, 17 and 12 recipients for the group of 4-10, 11-25 and 26-40 embryos, respectively. There was no difference between fusion rate (76.87% vs. 80.15%), full term pregnancy rate (16.66% vs. 27.27%) and percent of live puppies born (0.97% vs. 1.87%) for aspiration and squeezing method (P>0.05). Production efficiency of cloned dogs was significantly affected by the number of embryos transferred to each recipient. No pregnancy was established for the group of 4-10 embryos (n=7) and 26-40 embryos (n=12) while pregnancy was detected in 23.53% recipients received a group of 11-25 embryos (n=17). Among them, five (1.76%) live puppies were born (P<0.05). These data show an increase in the overall efficiency of SCNT in canine species.

Effects of insulin-transferrin-selenium in defined and porcine follicular fluid supplemented IVM media on porcine IVF and SCNT embryo production.

Insulin-transferrin-selenium (ITS) together has been used in different in vitro maturation system to support in vitro maturation of oocytes. The present study was designed to evaluate the effects of ITS in defined (0.1% PVA) and porcine follicular fluid (10% pFF) supplemented IVM media on the developmental competence of porcine oocytes. Three combinations of ITS, 10 mg/L insulin (Ins), 5.5mg/L transferrin (Tf) and 5 microg/L selenium (Se), 20mg/L Ins, 11 mg/L Tf and 10 microg/L Se, and 30 mg/L Ins, 16.5 mg/L TF and 15 microg/L Se, were used. The data were analyzed by one-way ANOVA and Tukey was used as the post hoc test. Both in the defined and pFF supplemented media, higher concentration of intracellular glutathione was observed in presence of ITS (4.6-4.8, and 6.9-7.1 picomole/oocyte for defined and pFF groups, respectively) compared to the respective control (2.1 and 4.3 picomole/oocyte for defined and pFF group, respectively). ITS decreased polyspermy and increased male pronucleus formation in both the defined and pFF supplemented medium. There was no difference in different treatment groups. The highest frequency of blastocyst formation rate and number of cells in blastocyst following IVF and SCNT was observed in pFF+ITS group (p<0.05). In conclusion, ITS addition during IVM improved the developmental competence of porcine oocytes in both the defined and pFF supplemented groups. Thus, we recommended to supplement porcine IVM medium with 10 microg/mL insulin, 5.5 microg/mL transferrin and 5 microg/mL selenium.