Genetic suppression of cryoprotectant toxicity

Area of Science:

• Cell Biology
• Genetics
• Biochemistry

Background:

• Cryoprotective agents (CPAs) are essential for cryopreservation but can cause toxicity.
• Understanding the genetic basis of CPA toxicity is crucial for improving cryopreservation techniques.

Purpose of the Study:

• To develop and apply a novel forward genetic screen for identifying mutations that confer resistance to cryoprotectant toxicity (CT).
• To identify specific genes and biochemical pathways involved in CPA resistance.

Main Methods:

• Utilized transposon-mediated mutagenesis to generate mutations in mammalian cells.
• Selected for resistance to M22, a whole-organ vitrification solution, to identify cryoprotectant toxicity resistance (CTR) mutants.
• Characterized six independent CTR mutants and identified associated genes.

Main Results:

• Identified six mutants resistant to M22, involving six previously unlinked biochemical pathways.
• Found mutations in genes including Gm14005, Myh9, Nrg2, Pura, Fgd2, Pim1, Opa1, Hes1, Hsbp1, and Ywhag.
• Observed cross-resistance to dimethyl sulfoxide (Me2SO) and improved survival after freezing/thawing in Me2SO for some mutants.

Conclusions:

• This forward genetic approach directly identifies genetic loci affecting CT, offering advantages over transcriptomic profiling.
• Provides the first direct evidence that specific molecular interventions can reduce CPA toxicity in mammalian cells.
• Opens new avenues for pharmacological strategies to mitigate cryoprotectant toxicity.