Sirt3 protects in vitro–fertilized mouse preimplantation embryos against oxidative stress–induced p53-mediated developmental arrest

Abstract

Sirtuins are a phylogenetically conserved NAD + -dependent protein deacetylase/ADP-ribosyltransferase family implicated in diverse biological processes. Several family members localize to mitochondria, the function of which is thought to determine the developmental potential of preimplantation embryos. We have therefore characterized the role of sirtuins in mouse preimplantation development under in vitro culture conditions. All sirtuin members were expressed in eggs, and their expression gradually decreased until the blastocyst stage. Treatment with sirtuin inhibitors resulted in increased intracellular ROS levels and decreased blastocyst formation. These effects were recapitulated by siRNA-induced knockdown of Sirt3, which is involved in mitochondrial energy metabolism, and in Sirt3 -/-embryos. The antioxidant N-acetyl-L-cysteine and lowoxygen conditions rescued these adverse effects. When Sirt3-knockdown embryos were transferred to pseudopregnant mice after long-term culture, implantation and fetal growth rates were decreased, indicating that Sirt3-knockdown embryos were sensitive to in vitro conditions and that the effect was long lasting. Further experiments revealed that maternally derived Sirt3 was critical. Sirt3 inactivation increased mitochondrial ROS production, leading to p53 upregulation and changes in downstream gene expression. The inactivation of p53 improved the developmental outcome of Sirt3-knockdown embryos, indicating that the ROS-p53 pathway was responsible for the developmental defects. These results indicate that Sirt3 plays a protective role in preimplantation embryos against stress conditions during in vitro fertilization and culture.

Prevention of maternal aging-associated oocyte aneuploidy and meiotic spindle defects in mice by dietary and genetic strategies

“…Second, both CR and PGC-1α interact with sirtuins as a means to control adaptive responses to energy availability (22)(23)(24)(25). Recent findings have shown that multiple sirtuins isoforms are expressed in mouse eggs, and that loss of mitochondrial-associated sirtuin-3 in oocytes increases mitochondrial production of reactive oxygen species leading to impaired preimplantation embryonic development (48). Such an outcome is consistent with a primary role for accumulated oxidative stress as a driving force behind declining oocyte quality with age and with the known inverse relationship between CR and aging-associated increases in mitochondrial oxidant damage in the body (19)(20)(21).…”

CFTR mediates bicarbonate-dependent activation of miR-125b in preimplantation embryo development

“…It has been previously demonstrated that the latency of p53 is required for normal preimplantation embryo development [43]. Stress-induced upregulation of p53 has been shown to result in developmental arrest of preimplantation embryo [44]. The latency of p53 in preimplantation embryo is well-documented to be maintained by autocrine stimulation through PI3K/Akt/Mdm2 pathway [43].…”

TEAD4 establishes the energy homeostasis essential for blastocoel formation

“…In fact, an increase in OXPHOS activity with respect to glycolytic activity in developing blastocysts positively correlates with the capacity of the embryo to develop to term following implantation (Gardner, 1998;Gardner, 2008). However, increased energy production via OXPHOS necessarily results in increased production of reactive oxygen species (ROS) (Adelman et al, 1988;Turrens, 1997;Finkel and Holbrook, 2000), which is normally attenuated by antioxidant defense mechanisms present within the embryo and its surroundings (Johnson and Nasr-Esfahani, 1994;Guérin et al, 2001;Orsi and Leese, 2001;Favetta et al, 2007;Betts and Madan, 2008;Kawamura et al, 2010;Zhang et al, 2010). In addition, it is likely that the oxygen level in the female reproductive tract is kept hypoxic relative to the atmospheric oxygen level (3-5% versus 21%) (Gardner and Leese, 1990) in order to minimize ROS production.…”