Earticle

초록

영어

Background: Heat stress (HS), driven by global climate change, adversely affects reproductive performance in livestock and mammals by impairing gamete development and reducing fertility. Exposure of oocytes to elevated temperatures during in vitro maturation (IVM) can induce persistent cellular stress that compromises subsequent embryonic development. However, the involvement of ATF5-mediated UPRmt signaling and GRP75-associated ER-mitochondria communication during early bovine embryogenesis under HS remains unclear. Methods: In this study, bovine cumulus–oocyte complexes (COCs) were matured for 22 h at either 38.5℃ (control; Con) or 41.5℃ (HS), followed by in vitro fertilization and embryo culture under standard conditions. Results: HS exposure during IVM significantly reduced cleavage and blastocyst formation rates (p < 0.01). Embryos derived from HS-exposed oocytes exhibited decreased mitochondrial membrane potential (ΔΨm), increased reactive oxygen species (ROS) production, and mitochondrial calcium (Ca2+) accumulation, suggesting disruption of GRP75 (known as HSPA9)-mediated ER-mitochondria communication. These embryos also showed increased expression of HSPA9 and HSPD1 at the cleavage stage, indicating persistence of stress signals beyond fertilization. Immunofluorescence analysis revealed enhanced nuclear localization of ATF5 in blastocysts, while qPCR analysis demonstrated increased expressions of ATF5-mediated UPRmt-related genes, including LONP1, HSPD1, and HSPA9. Conclusions: Collectively, these findings demonstrate that heat stress during oocyte maturation induces persistent mitochondrial dysfunction associated with GRP75- mediated mitochondrial Ca2+ dysregulation and ATF5-mediated UPRmt activation, which may represent an adaptive compensatory response in surviving bovine embryos.

목차

ABSTRACT
INTRODUCTION
MATERIALS AND METHODS
Chemicals
In vitro maturation (IVM)
In vitro production (IVP) of bovine embryos
Experimental design
Immunofluorescence (IF) staining
Mitochondrial staining (MitoTracker Orange, JC-1, Mito-SOX Red, Rhod-2)
TUNEL assay
Quantitative real-time PCR (qPCR)
Statistical analysis
RESULTS
Effects of HS-exposed oocytes on subsequent embryonic developmental competence in bovine embryos
Reduction of blastocyst developmental competence in bovine embryos derived from HS-exposed oocytes
Identification of mitochondrial stress response through UPRmt signaling in developed bovine blastocysts under HS condition
HS-exposed oocytes induce ATF5-mediated mitochondrial dysfunction in bovine blastocysts
DISCUSSION
CONCLUSION
SUPPLEMENTARY MATERIALS
REFERENCES

키워드

저자

• Hyo-Jin Park [ DU Center for Infertility, Daegu University/ Department of Infertility Medical Industry, College of Health and Biology, Daegu University ]
• Geun-Hwi Jo [ DU Center for Infertility, Daegu University/ Department of Biotechnology, College of Engineering, Daegu University ]
• Deog-Bon Koo [ DU Center for Infertility, Daegu University/ Department of Infertility Medical Industry, College of Health and Biology, Daegu University/ Department of Biotechnology, College of Engineering, Daegu University ] Corresponding Author

참고문헌

발행기관

간행물

관심저널 등록

• 간행물명

  Journal of Animal Reproduction and Biotechnology

• 간기

  계간

• pISSN

  2671-4639

• eISSN

  2671-4663

• 수록기간

  2019~2026

• 십진분류

  KDC 527 DDC 636