Date Published: September 27, 2018
Publisher: Public Library of Science
Author(s): Chawalit Siriboon, Tzai-Shiuan Li, Chao-Wu Yu, Ji-Wang Chern, Jyh-Cherng Ju, Yang Yu.
The histone deacetylase inhibitor (HDACi) has been investigated for treating cancers and many other diseases as well as enhancing the reprogramming efficiency in cloned embryos for decades. In the present study, we investigated the effects of two novel HDAC inhibitors, i.e., HDACi-14 and -79, at the concentrations of 0, 1, 2, or 4 μM on the development of embryos cloned by the oocyte bisection cloning technique (OBCT). Blastocyst rates for the reconstructed embryos reached 60% in the 2 μM HDACi-14-treated groups, which was higher (P < 0.05) compared to the untreated group (36.9%). Similarly, HDACi-79 treatment at 2 and 4 μM also conferred higher (P < 0.05) blastocyst rates than that of the untreated group (79.4, 74.2, and 50.0%, respectively). Both HDACi-14 and -79 treatments had no beneficial effect on total cell numbers and apoptotic indices of cloned embryos (P > 0.05). Histone acetylation profile by both HDACi-14 (2 μM) and -79 (2 μM) treatments demonstrated a drastic increase (P < 0.05) mainly in two-cell stage embryos when compared to the control group. After seeding on the feeder cells, the aggregated cloned blastocysts produced by the HDACi-79 treatment showed a significant increase of primary outgrowths compared to the control group (60.0% vs. 42.9%; P < 0.05). Finally, the cloned embryo-derived ES cell lines from aggregated cloned embryos produced from the HDACi-79-treated, HDACi-14-treated and control groups were established (5, 3, and 2 lines, respectively). In conclusion, the novel histone deacetylation inhibitors improve blastocyst formation and potentially increase the derivation efficiency of ES cell lines from the cloned porcine embryos produced in vitro. Depending on the purposes, some fine-tuning may be required to maximize its beneficial effects of these newly synthesized chemicals.
Embryonic stem (ES) cells represent a population of pluripotent cell type capable of self-renewal and differentiation into all somatic cell lineages. Meanwhile, somatic cell nuclear transfer (SCNT) has been envisioned as one promising way of generating personalized ES cells from specific somatic cells, which can be a valuable tool for clinical applications to study disease mechanisms, cell therapies, and even xenotransplantation [1–3]. In previous studies, ES or ES-like cells have also been established from SCNT derived embryos in various species such as mice, rabbits, bovine, primates, and pigs [3–9]. The establishment of ES cell lines in domestic animals could potentially impact studies of mammalian embryogenesis and regenerative medicine. Also, ES cells can be used to produce transgenic animals, such as pigs, serving as xenotransplantation donors. Pigs are also a desirable species to create pluripotent cell lines because of their immunological, physiological and functional similarities to humans . The morphology of porcine ES cell colony is also similar to that of human ES cells which is more like flattened cell aggregates rather than dome-shaped colonies (as in murine species).
Previous studies have shown that TSA treatment improved in vitro and in vivo development of cloned embryos in mice, rabbits, bovine and pigs [3,17,19–22,35–37]. Recently, scriptaid had been verified by some studies; their results demonstrating that scriptaid treatment significantly enhanced blastocyst rates and increased total cells number per blastocyst in pig and buffalo cloned embryos [23,24,38]. In addition, Su et al. suggested that oxamflatin treatments efficiently improved the development of bovine SCNT embryos in vitro . We therefore hypothesized that the newly synthesized HDACi (HDACi-14 and -79) also possessed the capacity to improve the development of cloned porcine embryos, as scriptaid, TSA and oxamflatin. To confirm this, the present study investigated the effect of two novel HDAC inhibitors on the development of porcine cloned embryos, the global histone acetylation patterns for nuclear reprogramming, and the derivation efficiency of ntES cell lines. We demonstrated that developmental competence of cloned embryos was improved by treatment with HDACi-14 or -79 when compared to that of the control embryo.