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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]

Strand displacement DNA synthesis is essential for DNA replication. Gp90, the sole DNA polymerase of Pseudomonas aeruginosa phage 1, can bypass multiply DNA lesions. However, whether it can perform strand displacement synthesis is still unknown. In this work, we found that gp90 exo― could perform strand displacement synthesis, albeit its activity and processivity were lower than those of primer extension. Gp90 exo― itself could not unwind Y-shaped or fork DNA. Tail and gap at DNA fork were necessary for efficient synthesis. High GC content obviously inhibited strand displacement synthesis. Consecutive GC sequence at the entrance of fork showed more inhibition effect on DNA synthesis than that in the downstream DNA fork. The fraction of productive polymerase and DNA complex (A values) was higher for fork than gap; while their average extension rates (k p values) were similar. However, both A and k p values were lower than those for the primer/template (P/T) substrate. The binding of gp90 exo― to fork was tighter than P/T or gap in the absence of dATP. In the presence of dATP to form ternary complex, the binding affinity of gp90 exo― to P/T or gap was increased compared with that in the binary complex. Abasic site, 8-oxoG, and O 6-MeG inhibited and even blocked strand displacement synthesis. This work shows that gp90 exo― could perform strand displacement DNA synthesis at DNA fork, discovering the presence of new functions of PaP1 DNA polymerase in DNA replication and propagation of PaP1. • Gp90 exo― could perform strand displacement DNA synthesis. • Tail and gap at DNA fork were necessary for efficient synthesis. • High GC content and DNA lesions obviously inhibited strand displacement synthesis. • E. coli Pol I KF exo― and Pol T7 ― could perform this synthesis, but Dpo4 and hPol ι could nearly not. • This work discovers new functions of polymerase in DNA replication and propagation of PaP1. [ABSTRACT FROM AUTHOR]

Extracellular vesicles (EVs) derived from parental cells could communicate with neighboring or distant recipient cells. The components in EVs, especially non-coding RNAs, including microRNAs, long non-coding RNAs, and circular RNAs, could regulate the functions of the recipient cells. Meanwhile, EVs could also be used as valuable biomarkers and drug delivery carriers. Moreover, environmental toxicants may alter EVs components and regulate EVs-mediated pathogenesis of various diseases. In this review, we mainly summarized the roles of EV-derived non-coding RNAs in the regulation of cell dysfunctions in various adverse pregnancy outcomes, such as preeclampsia (PE), gestational diabetes mellitus (GDM), and miscarriage. Moreover, the effects of environmental toxicants on the components and functions of EVs, as well as on their regulatory roles in these diseases, were also discussed. [ABSTRACT FROM AUTHOR]

rNTPs are structurally similar to dNTPs, but their concentrations are much higher than those of dNTPs in cells. rNTPs in solutions or rNMP at the primer terminus or embedded in template always inhibit or block DNA replication, due to the reduced Mg2+ apparent concentration, competition of rNTPs with dNTPs, and the extra repulsive interaction of rNTP or rNMP with polymerase active site. In this work, unexpectedly, we found rNTPs can promote T7 DNA replication with the maximal promotion at rNTPs/dNTPs concentration ratio of 20. This promotion was not due to the optimized Mg2+ apparent concentration or the direct incorporation of extra rNMPs into DNA. This promotion was dependent on the concentrations and types of rNTPs. Kinetic analysis showed that this promotion was originated from the increased fraction of polymerase-DNA productive complex and the accelerated DNA polymerization. Further evidence showed that more polymerase-DNA complex was formed and their binding affinity was also enhanced in the presence of extra rNTPs. Moreover, this promotion in T7 DNA replication also accelerated the lysis of T7-infected host Escherichia coli. This work discovered that rNTPs could promote DNA replication, completely different from the traditional concept that rNTPs always inhibit DNA replication. • Appropriate concentration ratios of rNTPs/dNTPs can promote T7 DNA replication. • rNTPs increased the amount of polymerase-DNA productive complex and the accelerated DNA polymerization. • More polymerases-DNA complex was formed and their binding affinity was enhanced in the presence of extra rNTPs. • This promotion for T7 DNA replication accelerated the lysis of its host E. coli infected with T7. [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]

Normal pregnancy is essential for human reproduction. However, BaP (benzo(a)pyrene) and its metabolite BPDE (benzo(a)pyrene‐7,8‐dihydrodiol‐9,10‐epoxide) could cause dysfunctions of human trophoblast cells and might further induce miscarriage. Yet, the underlying mechanisms remain largely unknown. Herein, we identified a novel upregulated lnc‐HZ04 and a novel downregulated miR‐hz04 in villous tissues of unexplained recurrent miscarriage (RM) relative to those in healthy control tissues and also in BPDE‐treated human trophoblast cells. Lnc‐HZ04 directly and specifically bound with miR‐hz04, diminished the reduction effects of miR‐hz04 on IP3R1 mRNA expression level and on IP3R1 mRNA stability, and then activated the Ca2+‐mediated IP3R1/p‐CaMKII/SGCB pathway, which further promoted trophoblast cell apoptosis. The miR‐hz04 target site on lnc‐HZ04 played crucial roles in these regulations. In normal trophoblast, relatively less lnc‐HZ04 and more miR‐hz04 suppressed this apoptosis pathway and gave normal pregnancy. After exposure to BPDE or in RM tissues, p53 was upregulated, which might promote p53‐mediated lnc‐HZ04 transcription. Relatively more lnc‐HZ04 and less miR‐hz04 activated this apoptosis pathway and might further induce miscarriage. BaP could also induce mice miscarriage by upregulating its corresponding murine apoptosis pathway. Therefore, BPDE‐induced apoptosis of human trophoblast cells was associated with the occurrence of miscarriage. This work discovered the regulation roles of lnc‐HZ04 and miR‐hz04 and provided scientific and clinical understanding of the occurrence of unexplained miscarriage. [ABSTRACT FROM AUTHOR]

Dichloroacetic acid (DCAA) and trichloroacetic acid (TCAA) are two typical non-volatile disinfection by-products (DBPs) found in drinking water. Increasing evidence has demonstrated that they show reproductive toxicity. However, whether they might have endocrine disrupting properties remains largely unknown. To discover this, we treated male mice or pregnant mice with 0, 1-, 102-, 103-, 104-, or 5 × 104-fold maximal concentration level (MCL) of DCAA or TCAA in drinking water. In male mice, the levels of testosterone in serum and androgen receptor (AR) in testis were declined with ≥ 103-fold MCL of DCAA (26.4 mg/kg/d) or TCAA (52.7 mg/kg/d). In pregnant mice, miscarriage rates were increased with ≥ 104-fold MCL of DCAA (264 mg/kg/d) or ≥ 103-fold MCL of TCAA. The levels of FSH in serum were increased and those of estradiol and progesterone were reduced with ≥ 103-fold MCL of DCAA or TCAA. The protein levels of estrogen receptors (ERα and ERβ) in ovary were reduced with ≥ 102-fold MCL of DCAA (2.64 mg/kg/d) or TCAA (5.27 mg/kg/d). Exposure to some certain fold MCL of DCAA or TCAA also altered the protein levels of ERα and ERβ in uterus and placenta. Exposure to 5 × 104-fold MCL of both DCAA and TCAA showed the combined effects. Therefore, both DCAA and TCAA could be considered as novel reproductive endocrine disrupting chemicals, which might be helpful for further assessment of the toxicological effects of DCAA and TCAA and the awareness of reproductive endocrine disrupting properties caused by DCAA and TCAA in drinking water. [Display omitted] • DCAA and TCAA function as endocrine-disrupting chemicals. • DCAA and TCAA reduce the levels of testosterone in serum and androgen receptor (AR) in testis of male mice. • DCAA and TCAA induce pregnant mouse miscarriage. • DCAA and TCAA increase follicle stimulating hormone levels and reduce estradiol and progesterone levels in serum of pregnant mice. • DCAA and TCAA reduce the levels of estrogen receptors (ERα and ERβ) in ovaries, uterus, and placenta of pregnant mice. [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]

BaP/BPDE exposure up-regulated free Fe2+ level and accelerated lipid peroxidation. Meanwhile, BaP/BPDE exposure also up-regulated MARCHF1 protein level, promoted its mediated ubiquitination degradation of GPX4, and hence decreased GPX4 protein level. Both pathways led to ferroptosis and further suppressed angiogenesis, which possibly induced miscarriage. Supplement with Gpx4 could efficiently suppress ferroptosis and recover angiogenesis in BPDE-exposed HUVECs and also alleviate miscarriage in BaP-exposed mouse miscarriage model. This study discovered novel toxicological effects and their underlying mechanisms that BaP/BPDE exposure induced ferroptosis, suppressed angiogenesis, and eventually induced miscarriage, as well as provided a promising approach to predict and treat against miscarriage. [Display omitted] • BPDE promoted HUVEC ferroptosis and suppressed angiogenesis by down-regulating GPX4 level. • BPDE promoted MARCHF1-mediated ubiquitination degradation of GPX4. • High level of BPDE-DNA adduct, ferroptosis, and defective angiogenesis in decidual tissues were associated with miscarriage. • Supplement with GPX4 suppressed ferroptosis, recovered angiogenesis, and alleviated miscarriage in BaP-exposed mouse model. • The levels of free Fe2+ and VEGFA in serum might reflect the risk of miscarriage. Environmental benzo(a)pyrene (BaP) and its ultimate metabolite BPDE (benzo(a)pyrene-7,8-dihydrodiol-9,10-epoxide) are universal and inevitable persistent organic pollutants and endocrine disrupting chemicals. Angiogenesis in placental decidua plays a pivotal role in healthy pregnancy. Ferroptosis is a newly identified and iron-dependent cell death mode. However, till now, BaP/BPDE exposure, ferroptosis, defective angiogenesis, and miscarriage have never been correlated; and their regulatory mechanisms have been rarely explored. In this study, we used assays with BPDE-exposed HUVECs (human umbilical vein endothelial cells), decidual tissues and serum samples collected from unexplained recurrent miscarriage and their matched healthy control groups, and placental tissues of BaP-exposed mouse miscarriage model. We found that BaP/BPDE exposure caused ferroptosis and then directly suppressed angiogenesis and eventually induced miscarriage. In mechanism, BaP/BPDE exposure up-regulated free Fe2+ level and promoted lipid peroxidation and also up-regulated MARCHF1 (a novel E3 ligase of GPX4) level to promote the ubiquitination degradation of GPX4, both of which resulted in HUVEC ferroptosis. Furthermore, we also found that GPX4 protein down-regulated the protein levels of VEGFA and ANG-1, two key proteins function for angiogenesis, and thus suppressed HUVEC angiogenesis. In turn, supplement with GPX4 could suppress ferroptosis, recover angiogenesis, and alleviate miscarriage. Moreover, the levels of free Fe2+ and VEGFA in serum might predict the risk of miscarriage. Overall, this study uncovered the crosstalk among BaP/BPDE exposure, ferroptosis, angiogenesis, and miscarriage, discovering novel toxicological effects of BaP/BPDE on human reproductive health. This study also warned the public to avoid exposure to polycyclic aromatic hydrocarbons during pregnancy to effectively prevent adverse pregnancy outcomes. [ABSTRACT FROM AUTHOR]