Zika virus (ZIKV) infection is associated with adverse pregnancy outcomes in humans, and infection in the first trimester can lead to miscarriage and stillbirth. Vertical and sexual transmissions of ZIKV have been demonstrated, yet the impact of infection during the initial stages of pregnancy remains unexplored. Here we defined the impact of ZIKV on early embryonic and placental development with a rhesus macaque model. During in vitro fertilization (IVF), macaque gametes were inoculated with a physiologically relevant dose of 5.48log10 plaque-forming units (PFU) of Zika virus/H.sapiens-tc/PUR/2015/PRVABC59_v3c2. Exposure at fertilization did not alter blastocyst formation rates compared to controls. To determine the impact of ZIKV exposure at implantation, hatched blastocysts were incubated with 3.26log10, 4.26log10, or 5.26log10 PFU, or not exposed to ZIKV, followed by extended embryo culture for 10 days. ZIKV exposure negatively impacted attachment, growth, and survival in comparison to controls, with exposure to 5.26log10 PFU ZIKV resulting in embryonic degeneration by day 2. Embryonic secretion of pregnancy hormones was lower in ZIKV-exposed embryos. Increasing levels of infectious virus were detected in the culture media post-exposure, suggesting that the trophectoderm is susceptible to productive ZIKV infection. These results demonstrate that ZIKV exposure severely impacts the zona-free blastocyst, whereas exposure at the time of fertilization does not hinder blastocyst formation. Overall, early stages of pregnancy may be profoundly sensitive to infection and pregnancy loss, and the negative impact of ZIKV infection on pregnancy outcomes may be underestimated.
Bibliographical noteFunding Information:
∗Correspondence: Jenna Kropp Schmidt, Ph.D., University of Wisconsin-Madison, Wisconsin National Primate Research Center, 1220 Capitol Ct., Madison, WI 53715-1299, USA; E-mail: firstname.lastname@example.org †Grant Support: This research was funded by the National Institutes of Health (NIH), grant P51 OD011106-54 to the Wisconsin National Primate Research Center, grant R21 HD091163-01 to T.G.G, and grants F31 HD100057 and T32GM081061 to L.N.B. The content is solely responsibility of the authors and does not necessarily represent the official views of Office of Research Infrastructure Programs (ORIP) or the NIH. Conference Presentation: This work was presented in part at the 51st Annual Meeting of the Society for the Study of Reproduction (10–13 July 2018, New Orleans, Louisiana), the 38th Annual Meeting of the American Society for Virology (14–18 July 2018, College Park, Maryland), and the 66th Annual Meeting Society for Reproductive Investigation (12–16 March 2019, Paris, France).
The authors would like to extend our thanks to the animal care and veterinary staff at the Wisconsin National Primate Research Center, especially Dr. Kevin Brunner for his surgical assistance in collecting oocytes for IVF experiments, as well as Dr. Kristen Bernard and members of the Golos lab for thoughtful discussion of these experiments. We would like to thank the University of Wisconsin-Madison College of Agriculture and Life Sciences Statistical Consulting Lab, particularly Nicholas Keuler, for statistical consultation. We would also like to thank the NIH and the Wisconsin National Primate Center for funding support.
- Zika virus
- in vitro fertilization (IVF)
- peri-implantation embryo
- preimplantation embryo