Controlling fertilization and cAMP signaling in sperm by optogenetics

Area of Science:

• Optogenetics
• Cellular Biology
• Reproductive Science

Background:

• Optogenetics offers precise control of cellular functions using light.
• While used in neurons, optogenetic control of second messengers like cAMP in vivo is less explored.
• Sperm motility and fertilization depend on cyclic AMP (cAMP) signaling regulated by soluble adenylyl cyclase (SACY).

Purpose of the Study:

• To develop and validate a transgenic mouse model for optogenetic control of cAMP in sperm.
• To investigate the role of cAMP in sperm behavior and fertilization using light-inducible methods.
• To assess the potential of optogenetics to restore biological functions, such as fertilization, in cells with impaired signaling.

Main Methods:

• Generation of transgenic mice expressing photoactivated adenylyl cyclase (bPAC) in sperm.
• Light stimulation to activate bPAC and modulate intracellular cAMP levels.
• Assessment of sperm motility, flagellar beat, and fertilization capacity in vitro.

Main Results:

• Light stimulation of bPAC-expressing sperm rapidly increased cAMP levels.
• Elevated cAMP accelerated sperm flagellar beat and altered swimming behavior.
• bPAC successfully restored motility and in vitro fertilization in sperm lacking endogenous SACY activity.

Conclusions:

• Optogenetic control of cAMP in sperm provides a non-invasive method to study signaling pathways.
• This approach allows precise control over single-cell behavior, specifically sperm motility.
• Optogenetics can restore fundamental biological processes like fertilization, offering therapeutic potential.