Analysis of Sex-Specific Prostanoid Production Using a Mouse Model of Selective Cyclooxygenase-2 Inhibition

Area of Science:

• Biochemistry
• Genetics
• Physiology

Background:

• Prostanoids, lipid mediators derived from arachidonic acid via cyclooxygenase (COX) enzymes, are crucial biomarkers of vascular function.
• Sex-specific differences in prostanoid production suggest distinct therapeutic strategies may be needed for various diseases.

Purpose of the Study:

• To investigate sex-dependent differences in cyclooxygenase (COX)-related metabolites using genetically modified mice.
• To model selective COX-2 inhibition through a specific COX2 enzyme mutation (Y385F).

Main Methods:

• Mated heterozygous mice for the COX2 Y385F mutation to generate wild-type, heterozygous, and mutant cohorts.
• Analyzed genotype distribution for Mendelian inheritance patterns.
• Measured prostanoid levels in peritoneal macrophages and urinary samples to identify sex-specific differences.

Main Results:

• Inheritance of the COX2 mutation deviated from Mendelian genetics, with fewer mutant offspring than expected.
• Prostaglandin E2 (PGE2) production in macrophages was COX2-dependent in both sexes; nitric oxide (NO) and COX2 pathway crosstalk appeared sex-specific.
• Urinary PGE2 levels differed significantly between sexes in COX2 mutant mice, with males showing reduced production.
• Female mice consistently produced higher levels of urinary thromboxane (11-dehydro TxB2) than males, suggesting a COX1-derived, sex-related difference.

Conclusions:

• Sex-related variations in COX-derived metabolites are evident.
• The nitric oxide (NO) pathway is also influenced by these sex-specific differences.