CLEC14A mediates trophoblast dysfunction in unexplained miscarriage by disrupting the cAMP/ERK signaling pathway

Unexplained miscarriage (UM) is a distressing pregnancy disorder often associated with impaired trophoblast function. This study aimed to investigate the role of C-type lectin domain family 14 member A (CLEC14A) in the pathogenesis of UM and to elucidate the underlying molecular mechanisms. Transcriptomic data from UM and healthy placental tissues (GSE123719) were analyzed. CLEC14A expression was validated in clinical chorionic villi samples (n = 10 per group) by immunohistochemistry, RT-qPCR, and Western blot. Gain-of-function studies were performed in HTR-8/SVneo trophoblast cells using lentiviral-mediated CLEC14A overexpression. Functional impacts on migration, invasion, and tube formation were assessed. RNA sequencing was used to identify dysregulated pathways, and key findings were confirmed by ELISA and Western blot. Rescue experiments were conducted using the adenylate cyclase inhibitor SQ22536. CLEC14A was significantly upregulated at both the mRNA and protein levels in villous tissues from UM patients compared to controls. In vitro, CLEC14A overexpression markedly suppressed trophoblast migration, invasion, and endothelial-like tube formation. Transcriptomic and mechanistic analyses revealed that CLEC14A overexpression activated the cAMP signaling pathway, leading to increased intracellular cAMP levels and Protein Kinase A (PKA) phosphorylation, while concurrently attenuating extracellular signal-regulated kinase (ERK) phosphorylation. The functional deficits and signaling perturbations induced by CLEC14A were effectively reversed by inhibition of cAMP synthesis. Our findings demonstrate that aberrant upregulation of CLEC14A impairs trophoblast function by activating the cAMP-PKA pathway and suppressing ERK signaling, thereby contributing to the pathogenesis of unexplained miscarriage. CLEC14A and its downstream signaling axis represent potential diagnostic and therapeutic targets for this condition.