Syncytiotrophoblast Vesicles Show Altered micro-RNA and Haemoglobin Content after Ex-vivo Perfusion of Placentas with Haemoglobin to Mimic Preeclampsia

Abstract

BackgroundCell-free foetal haemoglobin (HbF) has been shown to play a role in the pathology of preeclampsia (PE). In the present study, we aimed to further characterize the harmful effects of extracellular free haemoglobin (Hb) on the placenta. In particular, we investigated whether cell-free Hb affects the release of placental syncytiotrophoblast vesicles (STBMs) and their micro-RNA content.MethodsThe dual ex-vivo perfusion system was used to perfuse isolated cotyledons from human placenta, with medium alone (control) or supplemented with cell-free Hb. Perfusion medium from the maternal side of the placenta was collected at the end of all perfusion phases. The STBMs were isolated using ultra-centrifugation, at 10,000×g and 150,000×g (referred to as 10K and 150K STBMs). The STBMs were characterized using the nanoparticle tracking analysis, identification of surface markers and transmission electron microscopy. RNA was extracted and nine different micro-RNAs, related to hypoxia, PE and Hb synthesis, were selected for analysis by quantitative PCR.ResultsAll micro-RNAs investigated were present in the STBMs. Mir-517a, mir-141 and mir-517b were down regulated after Hb perfusion in the 10K STBMs. Furthermore, Hb was shown to be carried by the STBMs.ConclusionThis study showed that Hb perfusion can alter the micro-RNA content of released STBMs. Of particular interest is the alteration of two placenta specific micro-RNAs; mir-517a and mir-517b. We have also seen that STBMs may function as carriers of Hb into the maternal circulation.

Differential Proteomic Analysis of Syncytiotrophoblast Extracellular Vesicles from Early-Onset Severe Preeclampsia, using 8-Plex iTRAQ Labeling Coupled with 2D Nano LC-MS/MS

“…As an important placental factor, STBM was initially studied in normal pregnancy and PE by Redman et al at the University of Oxford, then various research teams worldwide are dedicated to this area and have developed the nomenclature of STBM to include terms such as syncytiotrophoblast microvilli [6], syncytiotrophoblast microvillous membrane [11,16,17,19], syncytiotrophoblast microparticles [15], syncytiotrophoblast microvesicles [23], syncytiotrophoblast-derived microparticles [8],and syncytiotrophoblast extracellular vesicles [38,39], etc. Increasing evidence shows that STBM have various functions relevant to PE, but the precise mechanism is not fully explained.…”

Placenta-derived extracellular vesicles: their cargo and possible functions

“…The shape of microvesicles may be cell-type dependent. EVs (50-600 nm) shed from perfused human placentas were spherical in shape as demonstrated by transmission electron microscopy (Cronqvist et al 2014). The shedding of placental material has been known for many years (Redman et al 2012).…”

“…Our own studies have shown that differential centrifugation alone is not sufficient to separate STB exosomes (30-100 nm) from STB microvesicles (100-1000 nm; Cronqvist et al 2014). STBEVs were isolated from medium following dual-placental perfusion taken from normal women at delivery as described in Cronqvist et al (2014).…”

Placental Extracellular Vesicles and Feto-Maternal Communication

“…The C19MC cluster of miRNA is expressed almost exclusively in the placenta (Luo et al 2009), and it was reported that placental exosomes predominately carry this family of miRNA (Donker et al 2012). In an in vitro model of preeclampsia, term placentae that have been perfused with hemoglobin produce microvesicles that showed a down-regulation of miRNA517a/b ( part of the C19MC cluster) (Cronqvist et al 2014), suggesting that changes in the content of nucleic acids in placental vesicles could contribute to the pathogenesis of preeclampsia.…”