Microcystin-LR prenatal exposure induces coronary heart disease through macrophage polarization imbalance mediated by trophoblast-derived extracellular vesicles.

Microcystin-leucine arginine (MC-LR) has been reported to exhibit placental toxicity, leading to potential adverse pregnancy outcomes. Placental abnormalities often coincide with congenital heart defects (CHD). However, the extent to which MC-LR-induced placental abnormalities contribute to CHD and the cellular mechanisms underlying this association remain unknown. In this study, we observed abnormal polarization of placental macrophages in pregnant mice exposed to MC-LR during pregnancy, and the embryos developed cardiac developmental defects that persisted into adulthood. Trophoblast-derived extracellular vesicles (T-EVs) increase in number during pregnancy and act as a critical signal in macrophage polarization. However, MC-LR significantly affected the miRNA expression profile of T-EVs. Upon internalization into macrophages, T-EV-derived miR-377-3p specifically targets the 3'UTR region of NR6A1 to inhibit gene expression. Silencing of transcription suppressor NR6A1 leads to abnormal activation of the downstream mTOR/S6K1/SREBP pathway, inducing metabolic reprogramming and ultimately leading to M1 polarization of macrophages. This study elucidated the placental mechanism underlying MC-LR-induced CHD for the first time, providing insights into the environmental risks associated with CHD.

Microcystin-LR prenatal exposure drives preeclampsia-like changes in mice by inhibiting the expression of TGF-ß and VEGFA.

Microcystin-leucine-arginine (MC-LR) is widespread in the water and food, which has suspected to be associated with adverse pregnancy outcomes. In the present study, we aim to assess the interaction between MC-LR exposure and preeclampsia development and elucidate the molecular events involved. After exposure to MC-LR during pregnancy, the mice developed hypertension and proteinuria, the typical symptoms of preeclampsia. This was associated with decreased invasiveness of placental trophoblast and vascular dysplasia caused by MC-LR through down-regulating VEGFA and TGF-ß expression via AKT/m-TOR/HIF-1α pathway. In addition, this conclusion has been confirmed in a case-control study. Significantly, the addition of Deferoxamine (DFM), a phosphorylated serine-threonine protein kinases (p-AKT) specific agonist, can antagonize the inhibitory effect of MC-LR on the expression of related proteins, which further ameliorate the migration and invasion ability of HTR-8/Svneo cells. To sum up, our study revealed the pathologic mechanism by which MC-LR lead to preeclampsia and emphasized the importance of pregnancy management.