Inhibition of BCAT1 expression improves recurrent miscarriage by regulating cellular dysfunction and inflammation of trophoblasts.

ABSTRACT

Sustained or chronic inflammation in the placenta can result in placental insufficiency, leading to adverse reproductive outcomes such as pregnancy loss. Branched-chain amino acid transaminase 1 (BCAT1) expresses in the placenta and is involved in the pathological inflammatory response, but its role in recurrent miscarriage (RM) has not been fully investigated. In the present study, we delved into the effects of BCAT1 on trophoblast inflammation induced by lipopolysaccharide (LPS) and a mouse model of pregnancy loss induced by LPS. In vitro, after the HTR-8/SVneo cells were treated with LPS and BCATc inhibitor 2 (a selective BCAT inhibitor), the cell apoptosis was verified by TUNEL assay, and the activity of caspase-3 and caspase-9 was detected. Real-time PCR, enzyme-linked immunosorbent assay (ELISA), and immunofluorescence (IF) were used to determine the expression of inflammatory cytokines (TNF-α, IL-6, and IL-1ß) and inflammasomes (NLRP3 and ASC) in LPS-treated trophoblast cells. Western blot analysis was performed to verify the expression of phospho-IκBα (p-IκBα) in cells and NF-κB p65 in the nuclei. IF staining was used to detect the nuclear translocation of NF-κB p65. The DNA binding activity of NF-κB was detected by an electrophoretic mobility shift assay (EMSA). The results demonstrated that inhibition of BCAT1 reduced trophoblast apoptosis, suppressed the release of proinflammatory cytokines, and prevented NLRP3 inflammasome activation in response to LPS. Additionally, BCAT1 inhibition blocked the activation of the NF-κB pathway in trophoblasts. This study highlights the potential therapeutic role of targeting BCAT1 in preventing adverse reproductive outcomes associated with chronic placental inflammation.