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The effects of fluid shear stress (FSS) on the human syncytiotrophoblast and its biological functions have never been studied. During pregnancy, the syncytiotrophoblast is the main source of placental growth factor (PlGF), a proangiogenic factor involved in the placental angiogenesis and the vascular adaptation to pregnancy. The role of FSS in regulating PlGF expression in syncytiotrophoblasts is unknown. We investigated the impact of FSS on the production and secretion of the PlGF by the human syncytiotrophoblasts in primary cell culture. Laminar and continuous FSS (1 dyn cm −2 ) was applied to human syncytiotrophoblasts cultured in a parallel-plate flow chambers. Secreted levels of PlGF, sFlt-1 (soluble fms-like tyrosin kinase-1), and prostaglandin E2 were tested by immunologic assay. PlGF levels of mRNA and intracellular protein were examined by RT-PCR and Western blot, respectively. Intracellular cAMP levels were examined by time-resolved fluorescence resonance energy transfer cAMP accumulation assay. Production of cAMP and PlGF secretion was significantly increased in FSS conditions compared with static conditions. Western blot analysis of cell extracts exposed to FSS showed an increased phosphorylation of protein kinase A substrates and cAMP response element-binding protein on serine 133. FSS-induced phosphorylation of cAMP response element-binding protein and upregulation of PlGF were prevented by inhibition of protein kinase A with H89 (3 μmol/L). FSS also triggers intracellular calcium flux, which increases the synthesis and release of prostaglandin E2. The enhanced intracellular cAMP in FSS conditions was blocked by COX1/COX2 (cyclooxygenase) inhibitors, suggesting that the increase in prostaglandin E2 production could activate the cAMP/protein kinase A pathway in an autocrine/paracrine fashion. FSS activates the cAMP/protein kinase A pathway leading to upregulation of PlGF in human syncytiotrophoblast. [ABSTRACT FROM AUTHOR]

Preeclampsia (PE) is a pregnancy-specific vascular disorder associated with endothelial dysfunction, hypertension, and proteinuria. The methylenetetrahydrofolate reductase (MTHFR) enzyme regulates essential cellular functions in pregnancy owing to its effects on folate metabolism and DNA methylation. Previous studies implicated the association of rs1801133 (C677T; Ala222Val) and rs1801131 (A1298C; Glu429Ala) in the MTHFR gene with PE in different ethnic groups, but with mixed outcomes., Methods: Study cases comprised 675 Tunisian pregnant women, of whom 350 PE presented with PE, and the remaining 325 normotensive women served as controls. Genotyping of C677T and A1298C variants was performed by real-time PCR., Results: There was no statistically significant difference in the minor allele frequencies of C677T and A1298C between preeclampsia cases and controls after adjusting for key covariates. In addition, the prevalence of MTHFR C677T and A1298C minor allele homozygote genotypes was significantly higher in PE cases. The association of 1298C/C, but not 677T/T, with PE persisted after adjusting for the main covariates. Carrying the (minor) 677T allele was associated with marginally higher BMI, significantly higher sFlt-1 serum levels, and median sFlt-1/PlGF ratio and sFlt-1/PlGF ratio ≥ 85. Setting the major allele homozygotes (C677/A1298) as a reference, haplotype analysis demonstrated a higher prevalence of C677/C1298 and T677/C1298 haplotypes (P = 0.03) in PE cases compared to controls, which persisted for C677/C1298, but not T677/C1298 after controlling for key covariates., Discussion: Our results support an association between MTHFR polymorphisms and increased risk of PE, and an imbalance of PE-associated sFLT-1/PlGF., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2025. Published by Elsevier B.V.)