Introduction: Human cytomegalovirus (HCMV) can cause congenital infection with risk of neurological disability. Maternal-fetal transmission is associated with placental inflammation. 5-lipoxygenase (5-LO) is the key enzyme in the biosynthesis of Leukotrienes (LTs), which are proinflammatory mediators. This study investigated the effect of HCMV infection on 5-LO expression and Leukotriene-B4 (LTB4) induction in human placentae and umbilical vein endothelial cells (HUVEC).
Methods: Seven placentae from fetuses with congenital HCMV infection and brain damage and six controls were stained with HCMV-immediate-early-antigen (HCMV-IEA) and 5-LO by immunohistochemistry. 5-hydroxyeicosatetraenoic acid (5-HETE) and LTB4 were measured in culture supernatant from ex vivo HCMV-infected placental histocultures by liquid chromatography. In vitro, HCMV infected HUVEC cells were analyzed for 5-LO mRNA and protein expression by real time PCR and immunofluorescence staining.
Results: HCMV-IEA was abundant in all HCMV infected placentae but absent in control placentae. 5-LO expression was higher in endothelial and smooth muscle cells of HCMV-infected placentae, compared to control placentae. HCMV infection induced an up-regulation of LTB4 in ex vivo placental explants with higher levels of LTB4 at 72 h compared to controls (p = 0.002). In vitro, 5-LO transcript and protein expression were significantly induced in HCMV-infected HUVEC, compared to the control cultures (p = 0.036).
Conclusion: The presence of HCMV coincided with high 5-LO expression in cells of in vivo HCMV infected placentae. HCMV induced up-regulation of 5-LO in both ex vivo HCMV-infected placental explants and HUVEC. HCMV induced LT-biosynthesis in congenitally infected placentae may have a role in pathogenesis of congenital HCMV disease.
Keywords: 5-Lipoxygenase; Endothelial cells; Histoculture; Human cytomegalovirus; LTB4; Placenta.
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