News | Embryonic Diapause Mechanism May Inform Infertility Treatment
Maintaining pregnancy during food shortages or harsh environmental conditions is challenging. Many mammalian embryos can therefore delay growth during periods of environmental stress and resume development when conditions improve. This developmental pause is called embryonic diapause. Understanding its mechanism may help improve infertility treatments such as embryo preservation. Researchers at the Chinese Academy of Sciences' Center for Excellence in Brain Science and Intelligence Technology in Shanghai have now discovered how embryos in food-deprived pregnant mice sense nutrient scarcity and enter diapause. Their findings were published in Development.
Food deprivation is a known trigger of embryonic diapause, but how embryos sense nutrient shortages in the mother's diet remains unclear. "Seasonal hunger is a common environmental stress in nature," explained Professor Qiang Sun, who led the study. "However, regulation of diapause in early embryos is not fully understood. We therefore decided to investigate whether nutrient deprivation induces embryonic diapause."
By comparing pregnant mice that were food-deprived with those fed normally, the team found that embryos in the food-deprived mice did not implant in the uterus and stopped growing at the early hollow ball-of-cells stage. The embryos remained viable and resumed development when transferred to well-nourished females.
To identify which nutrients are important in inducing diapause, the researchers cultured early mouse embryos in dishes containing different nutrients. Embryos grown without protein or carbohydrates stopped developing, while those exposed to normal nutrient levels continued to develop. The scientists then found that nutrient sensors in the embryos detect reduced protein or carbohydrate levels and trigger entry into diapause.
The findings suggest that embryos deprived of protein or carbohydrates may survive longer in the laboratory. In the future, this could improve infertility treatments, including embryo preservation. "We believe our study could inspire the development of new methods of embryo preservation," Professor Sun said. "Cryopreservation is widely used, but there is no consensus on when frozen embryos should be thawed and transferred. Many clinical studies suggest that conventional frozen embryo transfer may increase the risk of pregnancy complications. Alternative methods of preserving embryos are therefore needed."
Research on diapause may even have long-term implications for cancer treatment.
"Dormant cancer cells that persist after chemotherapy resemble embryos in diapause. We therefore hypothesize that deeper study of diapause mechanisms may benefit cancer treatment and reduce the risk of recurrence," Professor Qiang Sun added.
News | Embryonic Diapause Mechanism May Inform Infertility Treatment
News | Embryonic Diapause Mechanism May Inform Infertility Treatment
Maintaining pregnancy during food shortages or harsh environmental conditions is challenging. Many mammalian embryos can therefore delay growth during periods of environmental stress and resume development when conditions improve. This developmental pause is called embryonic diapause. Understanding its mechanism may help improve infertility treatments such as embryo preservation. Researchers at the Chinese Academy of Sciences' Center for Excellence in Brain Science and Intelligence Technology in Shanghai have now discovered how embryos in food-deprived pregnant mice sense nutrient scarcity and enter diapause. Their findings were published in Development.
Food deprivation is a known trigger of embryonic diapause, but how embryos sense nutrient shortages in the mother's diet remains unclear. "Seasonal hunger is a common environmental stress in nature," explained Professor Qiang Sun, who led the study. "However, regulation of diapause in early embryos is not fully understood. We therefore decided to investigate whether nutrient deprivation induces embryonic diapause."
By comparing pregnant mice that were food-deprived with those fed normally, the team found that embryos in the food-deprived mice did not implant in the uterus and stopped growing at the early hollow ball-of-cells stage. The embryos remained viable and resumed development when transferred to well-nourished females.
To identify which nutrients are important in inducing diapause, the researchers cultured early mouse embryos in dishes containing different nutrients. Embryos grown without protein or carbohydrates stopped developing, while those exposed to normal nutrient levels continued to develop. The scientists then found that nutrient sensors in the embryos detect reduced protein or carbohydrate levels and trigger entry into diapause.
The findings suggest that embryos deprived of protein or carbohydrates may survive longer in the laboratory. In the future, this could improve infertility treatments, including embryo preservation. "We believe our study could inspire the development of new methods of embryo preservation," Professor Sun said. "Cryopreservation is widely used, but there is no consensus on when frozen embryos should be thawed and transferred. Many clinical studies suggest that conventional frozen embryo transfer may increase the risk of pregnancy complications. Alternative methods of preserving embryos are therefore needed."
Research on diapause may even have long-term implications for cancer treatment.
"Dormant cancer cells that persist after chemotherapy resemble embryos in diapause. We therefore hypothesize that deeper study of diapause mechanisms may benefit cancer treatment and reduce the risk of recurrence," Professor Qiang Sun added.
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