RRC ID 30241
Author Bang S, Shin H, Song H, Suh CS, Lim HJ.
Title Autophagic activation in vitrified-warmed mouse oocytes.
Journal Reproduction
Abstract 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.
Volume 148(1)
Pages 11-9
Published 2014-7
DOI 10.1530/REP-14-0036
PII REP-14-0036
PMID 24760879
MeSH Animals Autophagy* / genetics Cold Temperature* Cold-Shock Response Cryopreservation* Embryo Culture Techniques Female Fertilization in Vitro Gene Expression Regulation, Developmental Green Fluorescent Proteins / genetics Green Fluorescent Proteins / metabolism Male Mice, Inbred ICR Mice, Transgenic Microtubule-Associated Proteins / genetics Microtubule-Associated Proteins / metabolism Oocytes / metabolism Oocytes / pathology* RNA, Messenger / metabolism Time Factors Vitrification*
IF 3.125
Times Cited 9
Mice GFP-LC3#53(RBRC00806)