Toll-like receptor 4 knockout mice are protected against PMOS-like pathogenesis

Area of Science:

• Endocrinology
• Immunology
• Reproductive Biology

Background:

• Polycystine metabolic ovarian syndrome (PMOS), previously known as polycystic ovary syndrome (PCOS), is a complex reproductive endocrine disorder.
• Chronic immune dysfunction is a recognized feature of PMOS, but the underlying immune activation mechanisms are not fully understood.
• Gut-derived lipopolysaccharide (LPS) may trigger systemic inflammation through Toll-like receptor 4 (TLR4) activation.

Purpose of the Study:

• To investigate the role of Toll-like receptor 4 (TLR4) in the development of PMOS-like pathology.
• To examine the impact of TLR4 deficiency on key features of PMOS in a mouse model.

Main Methods:

• A letrozole (LET)-induced mouse model was used to mimic PMOS-like pathology.
• Wild-type and TLR4 knockout (TLR4-/-) female mice were treated with LET.
• Serum LPS, luteinizing hormone (LH) levels, estrous cycling, fertility, gut barrier integrity, and inflammatory markers were assessed.

Main Results:

• LET-treated wild-type mice exhibited elevated serum LPS and lipopolysaccharide-binding protein (LBP) compared to LET-treated TLR4-/- mice.
• TLR4 deficiency significantly attenuated PMOS-like features, including elevated LH, anovulation, and metabolic dysfunction.
• LET-treated TLR4-/- mice maintained estrous cycling and fertility, preserved gut barrier integrity, and showed reduced inflammation.

Conclusions:

• Toll-like receptor 4 (TLR4) is a significant contributor to multiple aspects of PMOS-like pathology.
• Targeting TLR4-mediated inflammation presents a potential therapeutic strategy for women diagnosed with PMOS.