Targeting SAA expression via siRNA mitigates preterm birth induced by maternal inflammation.

Area of Science:

• Reproductive Immunology
• Maternal-Fetal Medicine
• Inflammation Biology

Background:

• Placental inflammation is a primary cause of preterm birth (PTB).
• Serum amyloid A (SAA) proteins (SAA1, SAA2) are inflammatory markers, but their role in placental inflammation is unclear.
• Current strategies to prevent PTB and improve neonatal outcomes are limited.

Purpose of the Study:

• To investigate the immune mechanisms of placental inflammation.
• To explore the therapeutic potential of targeting SAA2 using siRNA in a mouse model of PTB.
• To define the functional role of SAA2 in placental inflammation and macrophage activation.

Main Methods:

• A translational mouse model of sub-chronic maternal inflammation was used.
• siRNA-mediated targeting of Saa2 (siSaa2) was administered to pregnant mice.
• Placental SAA2 expression was examined in vivo, and macrophage responses to extracellular SAA2 were modeled in vitro using RAW264.7 cells to assess P2X7R signaling.

Main Results:

• SAA2 was primarily induced in placental trophoblast and endothelial cells during inflammation, acting as an extracellular mediator.
• siSaa2 administration improved PTB rates, placental morphology, and fetal brain development.
• SAA1 and SAA2 displayed distinct expression patterns in both mouse and human placentas.

Conclusions:

• Placental SAA2 is identified as a key mediator in inflammation-associated PTB.
• Targeted silencing of Saa2 using siRNA shows promise as a therapeutic strategy.
• This approach may mitigate placental injury and improve adverse fetal outcomes.