Inhibition of histone deacetylases enhances DNA damage repair in SCNT embryos.
Recent studies have shown that DNA damage affects embryo development and also somatic cell reprogramming into induced pluripotent stem (iPS) cells. It has been also shown that treatment with histone deacetylase inhibitors (HDACi) improves development of embryos produced by somatic cell nuclear transfer (SCNT) and enhances somatic cell reprogramming. There is evidence that increasing histone acetylation at the sites of DNA double-strand breaks (DSBs) is critical for DNA damage repair. Therefore, we hypothesized that HDACi treatment enhances cell programming and embryo development by facilitating DNA damage repair. To test this hypothesis, we first established a DNA damage model wherein exposure of nuclear donor cells to ultraviolet (UV) light prior to nuclear transfer reduced the development of SCNT embryos proportional to the length of UV exposure. Detection of phosphorylated histone H2A.x (H2AX139ph) foci confirmed that exposure of nuclear donor cells to UV light for 10 s was sufficient to increase DSBs in SCNT embryos. Treatment with HDACi during embryo culture increased development and reduced DSBs in SCNT embryos produced from UV-treated cells. Transcript abundance of genes involved in either the homologous recombination (HR) or nonhomologous end-joining (NHEJ) pathways for DSBs repair was reduced by HDACi treatment in developing embryos at day 5 after SCNT. Interestingly, expression of HR and NHEJ genes was similar between HDACi-treated and control SCNT embryos that developed to the blastocyst stage. This suggested that the increased number of embryos that could achieve the blastocyst stage in response to HDACi treatment have repaired DNA damage. These results demonstrate that DNA damage in nuclear donor cells is an important component affecting development of SCNT embryos, and that HDACi treatment after nuclear transfer enhances DSBs repair and development of SCNT embryos.
Department of Animal Science; McGill University; Ste. Anne de Bellevue, Quebec, Canada.
Rodrigo Camponogara
RC
Bohrer
Department of Animal Science; McGill University; Ste. Anne de Bellevue, Quebec, Canada.
Raj
R
Duggavathi
Department of Animal Science; McGill University; Ste. Anne de Bellevue, Quebec, Canada.
Vilceu
V
Bordignon
D000818:Animals; D053903:DNA Breaks, Double-Stranded / Q000187:drug effects / Q000528:radiation effects; D004260:DNA Repair / Q000187:drug effects* / Q000528:radiation effects; D004625:Embryo, Nonmammalian / Q000187:drug effects* / Q000502:physiology; D047108:Embryonic Development / Q000187:drug effects* / Q000528:radiation effects; D056572:Histone Deacetylase Inhibitors / Q000494:pharmacology*; D006655:Histone Deacetylases / Q000378:metabolism*; D006657:Histones / Q000378:metabolism; D053652:Nuclear Transfer Techniques; D009865:Oocytes / Q000187:drug effects / Q000502:physiology / Q000528:radiation effects; D021541:Sea Bream; D014466:Ultraviolet Rays
C468783:H2AX protein, human; D056572:Histone Deacetylase Inhibitors; D006657:Histones; D006655:Histone Deacetylases
DNA damage; HDACi; SCNT; cell reprogramming; embryo development; porcine