Heat stress in spermatogenesis: a redox-dependent decision network linking ROS, autophagy, and regulated cell death

Area of Science:

• Reproductive Biology
• Cellular Biology
• Toxicology

Background:

• Heat stress (HS) poses a significant threat to male reproductive health, affecting spermatogenesis.
• Reactive oxygen species (ROS) play a dual role in HS, causing damage and regulating cell fate.
• Understanding the redox-dependent mechanisms of HS on germ cells is crucial.

Purpose of the Study:

• To propose a unified framework for understanding how ROS dynamics govern cell fate decisions under heat stress.
• To elucidate the role of autophagy as a central regulatory checkpoint in heat stress-induced cell death.
• To identify stage-specific vulnerabilities within spermatogenesis to heat stress.

Main Methods:

• Conceptual framework development based on existing literature.
• Analysis of ROS dynamics and their impact on cellular pathways (antioxidant defenses, autophagy, lipid peroxidation, mitochondrial function).
• Examination of regulated cell death (RCD) pathways including apoptosis, ferroptosis, and pyroptosis.

Main Results:

• Heat stress induces a redox-dependent network controlling cell adaptation versus regulated cell death (RCD).
• Moderate ROS levels promote adaptive responses (antioxidant defenses, autophagy), while excessive ROS trigger RCD pathways.
• Autophagy acts as a critical regulator, modulating the balance between adaptation and cell death.
• Spermatogenesis exhibits stage-specific sensitivity, with spermatocytes being particularly vulnerable.
• Sertoli cells play a key role in regulating the redox microenvironment and amplifying damage.

Conclusions:

• Modulating redox balance is a promising strategy to mitigate heat stress-induced male reproductive damage.
• Antioxidant interventions must be carefully calibrated to preserve physiological redox signaling and autophagy.
• This framework provides mechanistic insights into heat stress-induced germ cell fate regulation and potential fertility preservation targets.