Development to Term of Cloned Cattle Derived from Donor Cells Treated with Valproic Acid

Abstract

Cloning of mammals by somatic cell nuclear transfer (SCNT) is still plagued by low efficiency. The epigenetic modifications established during cellular differentiation are a major factor determining this low efficiency as they act as epigenetic barriers restricting reprogramming of somatic nuclei. In this regard, most factors that promote chromatin decondensation, including histone deacetylase inhibitors (HDACis), have been found to increase nuclear reprogramming efficiency, making their use common to improve SCNT rates. Herein we used valproic acid (VPA) in SCNT to test whether the treatment of nuclear donor cells with this HDACi improves pre- and post-implantation development of cloned cattle. We found that the treatment of fibroblasts with VPA increased histone acetylation without affecting DNA methylation. Moreover, the treatment with VPA resulted in increased expression of IGF2R and PPARGC1A, but not of POU5F1. However, when treated cells were used as nuclear donors no difference of histone acetylation was found after oocyte reconstruction compared to the use of untreated cells. Moreover, shortly after artificial activation the histone acetylation levels were decreased in the embryos produced with VPA-treated cells. With respect to developmental rates, the use of treated cells as donors resulted in no difference during pre- and post-implantation development. In total, five clones developed to term; three produced with untreated cells and two with VPA-treated cells. Among the calves from treated group, one stillborn calf was delivered at day 270 of gestation whereas the other one was delivered at term but died shortly after birth. Among the calves from the control group, one died seven days after birth whereas the other two are still alive and healthy. Altogether, these results show that in spite of the alterations in fibroblasts resulting from the treatment with VPA, their use as donor cells in SCNT did not improve pre- and post-implantation development of cloned cattle.

Update and overview on assisted reproductive technologies (ARTs) in Brazil

“…After many years of research, no dramatic increase in cloning efficiency has been observed, with the rate of survival of cloned embryos still varying from 0 to 12% (De Bem et al, 2011;Sangalli et al, 2014;Gerger et al, 2016). Some improvements in survival rate can be expected by using specific and intensive management and clinical procedures during the perinatal and postnatal periods (Meirelles et al, 2010).…”

Trichostatin A-Mediated Epigenetic Transformation of Adult Bone Marrow-Derived Mesenchymal Stem Cells Biases theIn VitroDevelopmental Capability, Quality, and Pluripotency Extent of Porcine Cloned Embryos

“…Moreover, the use of the artificial modifiers of epigenomically conditioned gene expression leads to the inhibition of both chromatin condensation and transcriptional silencing of the genomic DNA of cultured somatic cells that are applied as a source of donor nuclei for the reconstruction of enucleated oocytes and subsequent generation of cloned embryos. The members of these epigenetic modifiers are 5-aza-2′-deoxycytidine (5-aza-dC) [ 37 , 39 – 41 ], S -adenosylhomocysteine (SAH) [ 42 ], trichostatin A (TSA) [ 6 , 19 , 36 , 38 , 43 ], valproic acid/sodium valproate (VPA/SV) [ 44 , 45 ], 6-(1,3-dioxo-1 H ,3 H -benzo[de]isoquinolin-2-yl)-hexanoic acid hydroxyamide called scriptaid [ 46 – 49 ], sodium butyrate (NaBu) [ 50 , 51 ], m -carboxycinnamic acid bis hydroxamide (CBHA) [ 30 , 52 ], and oxamflatin [ 29 , 53 ]. The onset of chromatin decondensation and gene transcriptional activity is evoked by nonspecific/nonselective blocking of the activity of either DNMTs by 5-aza-dC and SAH [ 41 , 42 ] or HDACs by the TSA, VPA, scriptaid, NaBu, CBHA, and oxamflatin [ 30 , 36 , 44 , 48 , 51 , 53 ].…”

Effects of Scriptaid on the Histone Acetylation, DNA Methylation and Development of Buffalo Somatic Cell Nuclear Transfer Embryos

“…Many studies have showed that the developmental defects of cloned embryos fail to eliminate epigeneticspecific markers completely and establish the related gamete markers themselves (Kishigami et al, 2006;Latham, 2005;Rideout et al, 2001;Shi et al, 2003). Moreover, many studies also found that an abnormal epigenetic modification might result in the developmental failure of SCNT embryos, such as abnormal histone acetylation and DNA methylation in reprogramming (Bohrer et al, 2014;Enright et al, 2005;Jafarpour et al, 2011;Sangalli et al, 2014). Histone acetylation is a part of epigenetic modification (Grunstein, 1997;Turner, 2002) and is related to transcriptional activation by regulating the chromosome structure.…”