Autophagic activation in vitrified-warmed mouse oocytes.
Vitrification involves the use of cryoprotectants (CPAs) and liquid nitrogen (LN2), which may cause osmotic damage and cryoinjury to oocytes. Autophagy is widely recognized as a survival or response mechanism elicited by various environmental and cellular stressors. However, the induction of autophagy in vitrified-warmed oocytes has not been examined. In this work, we investigated whether the vitrification-warming process induces autophagy in mouse oocytes. Metaphase II (MII) oocytes that were vitrified and stored in LN2 for at least 2 weeks were used in the study. In RT-PCR analyses, we observed that several Atg genes such as Atg5, Atg7, Atg12, LC3a (Map1lc3a), LC3b (Map1lc3b), and Beclin1 were expressed in MII mouse oocytes. Slight reduction in mRNA levels of Atg7 and Atg12 in vitrified-warmed oocytes was noted, and expression of these genes was not significantly influenced. Confocal live imaging analysis using oocytes from GFP-LC3 transgenic mice revealed that vitrified-warmed oocytes had a significantly higher number of GFP-LC3 puncta in comparison to fresh oocytes. The expression of BECLIN1 protein was also increased in vitrified-warmed oocytes. Treatment with 3-methyladenine, an inhibitor of autophagy, did not significantly affect the rates of oocyte survival, IVF, and embryonic development after warming and IVF. The results suggest that the observed autophagic activation in vitrified-warmed oocytes is a natural adaptive response to cold stress. Collectively, we show for the first time that vitrified-warmed mouse oocytes exhibit autophagic activation during warming and that this response is not induced by CPA-containing solutions. The induction of autophagy by cold temperature is first reported herein.
Department of Biomedical Science and TechnologyInstitute of Biomedical Science and Technology, Konkuk University, 120 Neungdong-ro, Gwangjin-gu, Seoul 143-701, KoreaDepartment of Biomedical ScienceCollege of Life Science, CHA University, Seoul 135-913, KoreaDepartment of Obstetrics and GynecologySeoul National University Bundang Hospital, Seongnam, Gyeonggi-do 463-707, Korea.
Soyoung
S
Bang
Department of Biomedical Science and TechnologyInstitute of Biomedical Science and Technology, Konkuk University, 120 Neungdong-ro, Gwangjin-gu, Seoul 143-701, KoreaDepartment of Biomedical ScienceCollege of Life Science, CHA University, Seoul 135-913, KoreaDepartment of Obstetrics and GynecologySeoul National University Bundang Hospital, Seongnam, Gyeonggi-do 463-707, Korea.
Hyejin
H
Shin
Department of Biomedical Science and TechnologyInstitute of Biomedical Science and Technology, Konkuk University, 120 Neungdong-ro, Gwangjin-gu, Seoul 143-701, KoreaDepartment of Biomedical ScienceCollege of Life Science, CHA University, Seoul 135-913, KoreaDepartment of Obstetrics and GynecologySeoul National University Bundang Hospital, Seongnam, Gyeonggi-do 463-707, Korea.
Haengseok
H
Song
Department of Biomedical Science and TechnologyInstitute of Biomedical Science and Technology, Konkuk University, 120 Neungdong-ro, Gwangjin-gu, Seoul 143-701, KoreaDepartment of Biomedical ScienceCollege of Life Science, CHA University, Seoul 135-913, KoreaDepartment of Obstetrics and GynecologySeoul National University Bundang Hospital, Seongnam, Gyeonggi-do 463-707, Korea.
Chang Suk
CS
Suh
Department of Biomedical Science and TechnologyInstitute of Biomedical Science and Technology, Konkuk University, 120 Neungdong-ro, Gwangjin-gu, Seoul 143-701, KoreaDepartment of Biomedical ScienceCollege of Life Science, CHA University, Seoul 135-913, KoreaDepartment of Obstetrics and GynecologySeoul National University Bundang Hospital, Seongnam, Gyeonggi-do 463-707, Korea hlim@konkuk.ac.kr.
Hyunjung Jade
HJ
Lim
D000818:Animals; D001343:Autophagy / Q000235:genetics; D003080:Cold Temperature; D058639:Cold-Shock Response; D015925:Cryopreservation; D046149:Embryo Culture Techniques; D005260:Female; D005307:Fertilization in Vitro; D018507:Gene Expression Regulation, Developmental; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D008297:Male; D008813:Mice, Inbred ICR; D008822:Mice, Transgenic; D008869:Microtubule-Associated Proteins / Q000235:genetics / Q000378:metabolism; D009865:Oocytes / Q000378:metabolism / Q000473:pathology*; D012333:RNA, Messenger / Q000378:metabolism; D013997:Time Factors; D058989:Vitrification
D008869:Microtubule-Associated Proteins; D012333:RNA, Messenger; D049452:Green Fluorescent Proteins