SMCP Maintains ROS Homeostasis During Sperm Mitochondrial Sheath Assembly

Area of Science:

• Reproductive Biology
• Sperm Biology
• Mitochondrial Function

Background:

• Abnormal sperm mitochondrial sheath morphology/function causes asthenozoospermia.
• Mechanisms of sperm mitochondrial sheath assembly and maturation are poorly understood.
• Sperm mitochondrial sheath protein (SMCP) regulation is of significant interest.

Purpose of the Study:

• To investigate the role of SMCP in sperm mitochondrial sheath assembly and function.
• To elucidate the molecular mechanisms underlying SMCP's function in spermiogenesis.
• To understand the link between SMCP, mitochondrial function, and male infertility.

Main Methods:

• Immunodetection of SMCP during spermiogenesis.
• Analysis of sperm motility and morphology in SMCP-deficient models.
• Integrative proteomic and functional analyses of sperm.
• Assessment of mitochondrial respiratory chain function and ATP production.
• Investigation of SMCP-GLRX interaction and ROS levels.

Main Results:

• SMCP is expressed during late spermiogenesis and retained in the mature sperm mitochondrial sheath.
• SMCP deficiency causes reduced sperm motility and male infertility without morphological changes.
• Loss of SMCP impairs mitochondrial respiratory chain function and ATP production.
• SMCP deficiency disrupts GLRX localization, elevates ROS levels, and compromises mitochondrial sheath function.

Conclusions:

• SMCP is a key regulator of functional module assembly in the sperm mitochondrial sheath.
• Sperm mitochondrial sheath assembly is critical for functional maturation and redox programming.
• The SMCP-GLRX complex acts as a localized antioxidant module during sperm development.