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Human trophoblast cells are crucial for healthy pregnancy. However, whether the defective homologous recombination (HR) repair of dsDNA break (DSB) in trophoblast cells may induce miscarriage is completely unknown. Moreover, the abundance of BRCA1 (a crucial protein for HR repair), its recruitment to DSB foci, and its epigenetic regulatory mechanisms, are also fully unexplored. In this work, it is identified that a novel lnc‐HZ10, which is highly experssed in villous tissues of recurrent miscarriage (RM) vs their healthy control group, suppresses HR repair of DSB in trophoblast cell. Lnc‐HZ10 and AhR (aryl hydrocarbon receptor) form a positive feedback loop. AhR acts as a transcription factor to promote lnc‐HZ10 transcription. Meanwhile, lnc‐HZ10 also increases AhR levels by suppressing its CUL4B‐mediated ubiquitination degradation. Subsequently, AhR suppresses BRCA1 transcription; and lnc‐HZ10 (mainly 1‐447 nt) interacts with γ‐H2AX; and thus, impairs its interactions with BRCA1. BPDE exposure may trigger this loop to suppress HR repair in trophoblast cells, possibly inducing miscarriage. Knockdown of murine Ahr efficiently recovers HR repair in placental tissues and alleviates miscarriage in a mouse miscarriage model. Therefore, it is suggested that AhR/lnc‐HZ10/BRCA1 axis may be a promising target for alleviation of unexplained miscarriage. [ABSTRACT FROM AUTHOR]

BPDE up-regulates lnc-HZ11, which down-regulates EGR1/NF-κB/CXCL12 pathway and suppresses trophoblast cell migration/invasion at intracellular levels. BPDE promotes donor trophoblast cells to secrete more EV-HZ11, which suppresses migration/invasion of the recipient trophoblast cells at intercellular levels, and is associated with unexplained miscarriage. Knockdown of murine lnc-Hz11 by EV-AS-Hz11 could efficiently alleviate miscarriage in BaP-exposed mice. The levels of EV-HZ11 in serum could predict the risk of miscarriage. [Display omitted] • BPDE up-regulates lnc-HZ11, which suppresses EGR1/NF-κB/CXCL12 and migration/invasion of trophoblast cells. • BPDE or lnc-HZ11 promotes trophoblast cells to secrete more EV-HZ11. • EV-HZ11 is transferred from donor cells to recipient cells and suppresses their migration/invasion. • Lnc-HZ11 and EV-HZ11 are closely associated with miscarriage. • Knockdown of murine lnc-Hz11 recovers migration/invasion and alleviates mouse miscarriage. • EV-HZ11 in serum predicts miscarriage risk. Extracellular vesicles (EVs) mediate the intercellular crosstalk by transferring functional cargoes. Recently, we have discovered that BaP/BPDE exposure suppresses trophoblast cell migration/invasion and induces miscarriage, which are also regulate by lncRNAs at intracelluar levels. However, the EVs-mediated intercellular regulatory mechanisms are completely unexplored. Specifically, whether EVs might transfer BPDE-induced toxic lncRNA to fresh recipient trophoblast cells and suppress their migration/invasion to further induce miscarriage is completely unknown. In this study, we find that BPDE exposure up-regulates a novel lnc-HZ11, which suppresses EGR1/NF-κB/CXCL12 pathway and migration/invasion of trophoblast cells. Intercellular studies show that EV-HZ11 (lnc-HZ11 in EVs), which is highly expressed in BPDE-exposed donor cells, suppresses EGR1/NF-κB/CXCL12 pathway and migration/invasion in recipient cells by transferring lnc-HZ11 through EVs. Analysis of villous tissues collected from UM (unexplained miscarriage) patients and HC (healthy control) group shows that the levels of BPDE-DNA adducts, lnc-HZ11 or EV-lnc-HZ11, and EGR1/NF-κB/CXCL12 pathway are all associated with miscarriage. Mouse assays show that BaP exposure up-regulates the levels of lnc-Hz11 or EV-Hz11, suppresses Egr1/Nf-κb/Cxcl12 pathway, and eventually induces miscarriage. Knockdown of lnc-Hz11 by injecting EV-AS-Hz11 could effectively alleviate miscarriage in BaP-exposed mice. Furthermore, EV-HZ11 in serum samples could well predict the risk of miscarriage. Collectively, this study not only discovers EVs-HZ11-mediated intercellular mechanisms that BaP/BPDE suppresses trophoblast cell migration/invasion and induces miscarriage but also provides new approach for treatment against unexplained miscarriage through EV-HZ11. [ABSTRACT FROM AUTHOR]

Benzo(a)pyrene (BaP) is a ubiquitous environmental endocrine-disrupting chemical that is known to have toxic effects on reproduction. However, the underlying mechanisms describing how BaP and its metabolite benzo[a]pyrene-7, 8-diol-9, 10-epoxide (BPDE) induce recurrent pregnancy loss (RPL) are still largely unclear. In this study, we identified a novel long non-coding RNA (lnc-HZ07, NCBI MT936329) that was upregulated in trophoblast cells after exposure to BPDE, and lnc-HZ07 expression was significantly higher in RPL villous tissues than that in control villous tissues. Knockdown of lnc-HZ07 promoted trophoblast cell migration, whereas overexpression of lnc-HZ07 inhibited trophoblast cell migration. Further study showed that lnc-HZ07 inhibited trophoblast migration by downregulating matrix metalloproteinase 2 (MMP2) expression via dephosphorylation of AKT. These results demonstrated a novel regulatory pathway in which BaP downregulated AKT phosphorylation and inhibited MMP2 expression by upregulating lnc-HZ07, suggesting that lnc-HZ07 could be considered as a potential pathological marker of BaP-induced RPL and therapeutic target for this disease. [ABSTRACT FROM AUTHOR]

Proper migration and invasion of trophoblast cells into endometrium is vital for successful embryo implantation during early pregnancy. Benzo[a]pyrene-7, 8-diol-9, 10-epoxide (BPDE) is an ultimate carcinogenic product of benzo[a]pyrene (BaP), which causes multiple trophoblast-related diseases. However, the mechanism of BPDE-inhibited migration/invasion of trophoblast cells is still unclear. In this work, we found that BPDE significantly inhibited the filopodia formation and migration/invasion of human trophoblast Swan 71 cells. BPDE up-regulated the level of miR-194-3p, which further inhibited the phosphoinositide 3-kinase (PI3K)/AKT/ cell division cycle 42/ p21 (RAC1) activated kinase 1 signaling pathway and depressed the filophdia formation of Swan71 cells. Addition of 740 Y-P, the activator of phosphoinositide 3-kinase, could stimulate cell migration/invasion, confirming the involvement of this pathway. Knock-down of miR-194-3p up-regulated this pathway and promoted filopodia formation and migration/invasion. Conversely, overexpression of miR-194-3p down-regulated this pathway and inhibited cell migration/invasion. Therefore, miR-194-3p takes important roles in the BPDE-inhibited filopodia formation and cell migration/invasion, providing valuable information in the BPDE-induced dysfunctions of human extravillous trophoblast cells. [ABSTRACT FROM AUTHOR]