Regulation of [Ca²⁺]_i oscillations and mitochondrial activity by various calcium transporters in mouse oocytes

Area of Science:

• Reproductive Biology
• Cell Physiology
• Molecular Medicine

Background:

• Oocyte activation inefficiency contributes to female infertility.
• Intracellular calcium (Ca²⁺) dynamics are critical regulators of oocyte activation.

Purpose of the Study:

• To investigate the roles of specific Ca²⁺ channels in regulating intracellular Ca²⁺ ([Ca²⁺]_i) oscillations and mitochondrial membrane potential during oocyte activation.
• To understand the impact of these channels on oocyte cytoskeleton stability and subsequent embryo development.

Main Methods:

• Real-time recording of [Ca²⁺]_i oscillations and mitochondrial membrane potential.
• Utilized inhibitors for sarcoplasmic/endoplasmic reticulum Ca²⁺ATPases (SERCAs), transient receptor potential (TRP) ion channel subfamily member 7 (TRPM7), T-type Ca²⁺ channels, and calcium channel Orai1.

Main Results:

• SERCAs, TRPM7, and T-type Ca²⁺ channels are essential for initiating and maintaining [Ca²⁺]_i oscillations.
• These oscillations are necessary for mitochondrial membrane potential elevation, oocyte cytoskeleton stability, and successful embryo development.
• Orai1's role was also investigated in the context of these processes.

Conclusions:

• Specific Ca²⁺ transport mechanisms, including SERCAs, TRPM7, and T-type channels, play pivotal roles in oocyte activation.
• Understanding calcium transport mechanisms provides a foundation for improving oocyte activation in assisted reproduction.
• Targeting these channels could enhance fertility treatments.