Expression pattern of pluripotent markers in different embryonic developmental stages of buffalo (Bubalus bubalis) embryos and putative embryonic stem cells generated by parthenogenetic activation.

In this study, we describe the production of buffalo parthenogenetic blastocysts and subsequent isolation of parthenogenetic embryonic stem cell (PGESC)-like cells. PGESC colonies exhibited dome-shaped morphology and were clearly distinguishable from the feeder layer cells. Different stages of development of parthenogenetic embryos and derived embryonic stem cell (ESC)-like cells expressed key ESC-specific markers, including OCT-4, NANOG, SOX-2, FOXD3, REX-1, STAT-3, TELOMERASE, NUCLEOSTEMIN, and cMYC. Immunofluorescence-based studies revealed that the PGESCs were positive for surface-based pluripotent markers, viz., SSEA-3, SSEA-4, TRA 1-80, TRA 1-60, CD-9, and CD-90 and exhibited high alkaline phosphatase (ALP) activity. PGEC cell-like cells formed embryoid body (EB)-like structures in hanging drop cultures and when cultured for extended period of time spontaneously differentiated into derivatives of three embryonic germ layers as confirmed by RT-PCR for ectodermal (CYTOKERATIN8, NF-68), mesodermal (MSX1, BMP-4, ASA), and endodermal markers (AFP, HNF-4, GATA-4). Differentiation of PGESCs toward the neuronal lineage was successfully directed by supplementation of serum-containing media with retinoic acid. Our results indicate that the isolated ESC-like cells from parthenogenetic blastocyst hold properties of ESCs and express markers of pluripotency. The pluripotency markers were also expressed by early cleavage-stage of buffalo embryos.

Roscovitine treatment improves synchronization of donor cell cycle in G0/G1 stage and in vitro development of handmade cloned buffalo (Bubalus bubalis) embryos.

This study investigated the effects of serum-starvation, total confluence, and roscovitine treatment on cell-cycle synchronization of buffalo ear skin fibroblasts to the G0/G1 stage and on the developmental competence of cloned embryos. Serum starvation of total confluence cultures for 24 h had a higher (p<0.05) proportion of cells at G0/G1 stage (94.4%) compared with serum starved cyclic and nonstarved confluent cultures (76.8 and 86.0%, respectively), whereas differences between cyclic cells with or without serum starvation were not significant. The proportion of cells at G0/G1 was higher (p<0.05) with 20 and 30 µM roscovitine treatment than that with 10 µM (94.4, 96.4, and 86.6%, respectively), which was similar to that for total confluence (86.0%). MTT assay showed that cell viability decreased as dose of roscovitine increased. The blastocyst rate was significantly higher (p<0.05) when nuclear transfer embryos were reconstructed using donors cells from total confluence, confluence serum starved, and roscovitine-treated (20 and 30 µM) groups (48.8, 48.9, 57.9, and 62.9%, respectively) compared to nontreated cyclic cells (20.2%). However, the cleavage rate and total cell number of cloned embryos were similar for all the groups. The number of ICM cells was improved by 30 µM roscovitine treatment (45.25 ± 2.34). The cryosurvival rate of blastocysts derived from cells synchronized with 20 or 30 µM roscovitine was higher compared to that for total confluence group (33.6, 37.8 vs. 23.8%). In conclusion, treatment with 30 µM roscovitine is optimal for harvesting G0/G1 stage cells for producing high quality cloned buffalo embryos, and that it is better than serum-starvation or total confluence for cell synchronization.