Background The accumulation of reactive oxygen species (ROS) resulting from upregulated levels of oxidative stress is commonly implicated in preeclampsia (PE). Ferroptosis is a novel form of iron-dependent cell death instigated by lipid peroxidation that likely plays an important role in PE pathogenesis. This study aimed to investigate the expression profiles and functions of ferroptosis-related genes (FRGs) in early-onset preeclampsia (EOPE) and late-onset preeclampsia (LOPE). Methods Gene expression data and clinical information were downloaded from the Gene Expression Omnibus (GEO) database. The “limma” R package was used to screen differentially expressed genes. Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG) and protein–protein interaction (PPI) network analyses were conducted to investigate the bioinformatics functions and molecular interactions of significantly different FRGs. Quantitative reverse transcription polymerase chain reaction (RT-qPCR) was used to verify the expression of hub FRGs in PE. Results A total of 4215 differentially expressed genes (DEGs) were identified between EOPE and preterm cases while 556 DEGs were found between LOPE and term controls. Twenty significantly different FRGs were identified in EOPE subtypes, while only 3 FRGs were identified in LOPE subtypes. Functional enrichment analysis revealed that the differentially expressed FRGs were mainly involved in EOPE and enriched in hypoxia- and iron-related pathways, such as the response to hypoxia, iron homeostasis and iron ion binding process. PPI network analysis and verification by RT-qPCR resulted in the identification of the following five FRGs of interest: FTH1, HIF1A, FTL, MAPK8 and PLIN2. Conclusions EOPE and LOPE have distinct underlying molecular mechanisms, and ferroptosis may be mainly implicated in the pathogenesis of EOPE. Further studies are necessary for deeper inquiry into placental ferroptosis and its role in the pathogenesis of EOPE.

Background: Histone lactylation, a novel epigenetic modification induced by hypoxia and lactate, plays an important role in regulating gene expression. However, the role of histone lactylation in the pathogenesis of preeclampsia remains unknown.Methods: Placentas from preeclamptic patients and control pregnant women were collected for protein immunoassay to detect the expression level of histone lactylation, and two trophoblast cell lines were used to simulate the effect of histone lactylation on genes.Results: We found that lactate and histone lactylation levels were increased in preeclamptic placentas. In vitro, hypoxia was demonstrated to induce histone lactylation by promoting the production of lactate in human-trophoblastderived cell line (HTR-8/SVneo) and human first-trimester extravillous trophoblast cell line (TEV-1) cells. In addition, 152 genes were found to be upregulated by both hypoxia exposure and sodium L-lactate treatment in HTR-8/SVneo cells. These genes were mainly enriched in the pathways including the response to hypoxia, cell migration and focal adhesion. Among the 152 genes, nine were upregulated in preeclamptic placentas. Most noteworthy, two upregulated fibrosis-related genes, FN1 and SERPINE1, were promoted by hypoxia through histone lactylation mediated by the production of lactate. Conclusions:The present study demonstrated the elevated levels of histone lactylation in preeclamptic placentas and identified fibrosis-related genes that were promoted by histone lactylation induced by hypoxia in trophoblast cells, which provides novel insights into the mechanism of placental dysfunction in preeclampsia.

Background:This study aims to investigate the effects of saturated free fatty acid on calcification and SIRT6 expression in vascular smooth muscle cells (VSMCs) and the role of SIRT6 in regulating VSMC calcification.Methods:Sprague–Dawley rats were randomly allocated to two groups: rats with normal diet (ND) and high-fat diet (HFD) from 4 to 12 weeks. At 12 weeks, part rats randomly selected from ND and HFD were administrated with vitamin D3 and nicotine to establish a model of vascular calcification. Thoracic aortas were collected from treatment rats at 16 weeks for assaying vascular calcification and related protein expression. Primary VSMCs isolated from Sprague–Dawley rats were used for investigating the effects of palmitic acid on VSMCs’ calcification, apoptosis and target protein expression.Results:HFD-facilitated calcification in medial aorta, with decreased SIRT6 expression in VSMCs of aortas. Palmitic acid decreased SIRT6 expression while increased calcification, apoptosis and protein expression of BMP2 and RUNX2 in primary VSMCs. Overexpression of SIRT6 could, partially or completely, rescue the palmitic acid-induced elevation of calcification, apoptosis and expression of BMP2 and RUNX2.Conclusion:This study demonstrated that vascular calcification induced by HFD was linked to the palmitic acid-induced downregulation of SIRT6. Overexpression of SIRT6 could decrease palmitic acid-induced calcification and apoptosis in VSMCs.

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Background: The accumulation of ROS resulting from upregulated levels of oxidative stress is commonly implicated in preeclampsia (PE). Ferroptosis is a novel form of iron-dependent cell death instigated by lipid peroxidation likely plays important role in PE pathogenesis. This study aims to investigate expression profiles and functions of the ferroptosis-related genes (FRGs) in early- and late-onset preeclampsia.Methods: The gene expression data and clinical information were downloaded from GEO database. The “limma” R package was used for screening differentially expressed genes. GO(Gene Ontology), Kyoto Encyclopedia of Genes and Genomes(KEGG) and protein protein interaction (PPI) network analyses were conducted to investigate the bioinformatics functions and molecular interactions of significantly different FRGs. Quantitative real-time reverse transcriptase PCR was used to verify the expression of hub FRGs in PE.Results: A total number of 4,215 DEGs were identified between EOPE and preterm cases and 3,356 DEGs were found between EOPE and LOPE subtypes. 20 significantly different FRGs were identified in EOPE, while only 3 in LOPE. Functional enrichment analysis revealed that the differentially expressed FRGs was mainly involved in EOPE and enriched in hypoxia- and iron-related pathways, such as response to hypoxia, iron homeostasis and iron ion binding process. The PPI network analysis and verification by RT-qPCR resulted in the identification of the following six interesting FRGs: FTH1, HIF1A, FTL, IREB2, MAPK8 and PLIN2. Conclusions: EOPE and LOPE owned distinct underlying molecular mechanisms and ferroptosis may be mainly implicated in pathogenesis of EOPE. Further studies are necessary for deeper inquiry into placental ferroptosis and its role in the pathogenesis of EOPE.