High glucose-induced p66Shc mitochondrial translocation regulates autophagy initiation and autophagosome formation in syncytiotrophoblast and extravillous trophoblast.

BACKGROUND: p66Shc, as a redox enzyme, regulates reactive oxygen species (ROS) production in mitochondria and autophagy. However, the mechanisms by which p66Shc affects autophagosome formation are not fully understood. METHODS: p66Shc expression and its location in the trophoblast cells were detected in vivo and in vitro. Small hairpin RNAs or CRISPR/Cas9, RNA sequencing, and confocal laser scanning microscope were used to clarify p66Shc's role in regulating autophagic flux and STING activation. In addition, p66Shc affects mitochondrial-associated endoplasmic reticulum membranes (MAMs) formation were observed by transmission electron microscopy (TEM). Mitochondrial function was evaluated by detected cytoplastic mitochondrial DNA (mtDNA) and mitochondrial membrane potential (MMP). RESULTS: High glucose induces the expression and mitochondrial translocation of p66Shc, which promotes MAMs formation and stimulates PINK1-PRKN-mediated mitophagy. Moreover, mitochondrial localized p66Shc reduces MMP and triggers cytosolic mtDNA release, thus activates cGAS/STING signaling and ultimately leads to enhanced autophagy and cellular senescence. Specially, we found p66Shc is required for the interaction between STING and LC3II, as well as between STING and ATG5, thereby regulates cGAS/STING-mediated autophagy. We also identified hundreds of genes associated several biological processes including aging are co-regulated by p66Shc and ATG5, deletion either of which results in diminished cellular senescence. CONCLUSION: p66Shc is not only implicated in the initiation of autophagy by promoting MAMs formation, but also helps stabilizing active autophagic flux by activating cGAS/STING pathway in trophoblast.

Stanniocalcin2 inhibits the epithelial-mesenchymal transition and invasion of trophoblasts via activation of autophagy under high-glucose conditions.

Maternal pregnancy hyperglycemia is often accompanied by placental dysfunction. During placental development, epithelial-mesenchymal transition (EMT) contributes to the transformation of relatively noninvasive trophoblasts into highly invasive extravillous trophoblasts (EVTs). However, the specific role of EMT in placentas under hyperglycemia environments remains relatively unexplored. Stanniocalcin2 (STC2) regulates EMT in many cancers. In this study, we first demonstrated that STC2 expression was upregulated in GDM placenta. We found that STC2 activated autophagy and suppressed EMT in high-glucose-treated EVTs and was associated with a lack of invasiveness. Specifically, STC2 inhibited the interactions between p62/SQSTM1 (p62) and EMT transcription factors to promote the degradation of Twist1 and Snail via a proteasome-dependent pathway. Furthermore, the PI3K/AKT/AMPK signaling pathway was involved in the regulation of autophagy and EMT by STC2. Taken together, our results reveal that STC2 may serve as a potential prognostic biomarker in GDM and sheds light on the regulatory mechanisms of trophoblast invasion.

ARID1A-dependent permissive chromatin accessibility licenses estrogen-receptor signaling to regulate circadian rhythms genes in endometrial cancer.

Estrogen receptor α (ER) acts as an oncogenic signal in endometrial endometrioid carcinoma. ER binding activity largely depends on chromatin remodeling and recruitment of transcription factors to estrogen response elements. A deeper understanding of these regulatory mechanisms may uncover therapeutic targets for ER-dependent endometrial cancers. We show that estrogen induces accessible chromatin and ER binding at a subset of enhancers, which form higher-order super enhancers that are vital for ER signaling. ER positively correlates with active enhancers in primary tumors, and tumors were effectively classified into molecular subtypes with chromatin accessibility dynamics and ER-dependent gene signature. ARID1A binds within ER-bound enhancers and regulates ER-dependent transcription. Knockdown of ARID1A or fulvestrant treatment profoundly affects the gene-expression program, and inhibits cell growth phenotype by affecting the chromatin environment. Importantly, we found dysregulated expression of circadian rhythms genes by estrogen in cancer cells and in primary tumors. Knockdown of ARID1A reduces the chromatin accessibility and ER binding at enhancers of the circadian gene ARNTL and BHLHE41, leading to a decreased expression of these genes. Altogether, we uncover a critical role for ARID1A in ER signaling and therapeutic target in ER-positive endometrial cancer.

Silencing DAPK3 blocks the autophagosome-lysosome fusion by mediating SNAP29 in trophoblast cells under high glucose treatment.

Autophagy plays an essential role in gestational diabetes mellitus (GDM). Death-associated protein kinase-3 (DAPK3) regulates a variety of cellular functions; however, the relationship between DAPK3 and autophagy is unknown. In this study, we aim to investigate whether DAPK3 is associated with autophagy in GDM, and we found that DAPK3 was upregulated in the placenta of GDM patients and extravillous trophoblast cells under high-glucose conditions. Silencing DAPK3 decreased the assembly of the STX17-SNAP29-VAMP8 complex, leading to the blockade of autophagosome-lysosome fusion by mediating synaptosomal-associated protein 29 (SNAP29). Moreover, knockdown of DAPK3 ameliorates cell invasion and mediates autophagy in high glucose, and does not alter the expression of autophagy-related genes in normal glucose. Our study demonstrates the significance of DAPK3 in autophagy and GDM, which may provide new insights into the molecular mechanisms regulating trophoblast invasion.