Peptidoglycan Induces Necrosis and Regulates Cytokine Production in Murine Trophoblast Stem Cells

Abstract

Problem-Intrauterine bacterial infection during pregnancy may lead to adverse outcome. The objective of this study was to assess whether peptidoglycan (PGN) derived from Gram-positive bacteria induces trophoblast stem (TS) cell death or alters TS cell cytokine production.Method of study-TLR transcript expression was assessed by RT-PCR. Protein expression was determined by confocal microscopy or flow cytometry. 7-Aminoactinomycin D (7-AAD) staining was used to assess TS cell death. Morphological features of cell death were evaluated by transmission electron microscopy. The presence of cleaved caspase-3 and HMGB1 protein was examined by western blot. Cytokine levels in cell supernatants were determined using a mouse cytokine 23-plex panel.Results-TLR2 and TLR4 protein was expressed from the 1-cell through the blastocyst stage of murine embryo development. Murine TS cells expressed TLR2 and TLR6 but not TLR1 or TLR4 RNA. Only TLR2 protein was detected at the plasma membrane of TS cells. PGN induced TS cell death by a caspase-3 independent mechanism. The cell death pathway induced by PGN was morphologically consistent with necrosis. Finally, PGN induced HMGB1 release and increased MIP-1β secretion while inhibiting the constitutive release of RANTES.Conclusion-PGN-induced TS cell necrosis and the subsequent release of HMGB1 and MIP-1β may regulate an infection-induced inflammatory response at the maternal-fetal interface and thus may play a role in the pathogenesis of infection-associated pregnancy complications.

SNPs in toll-like receptor (TLR) genes as new genetic alterations associated with congenital toxoplasmosis?

“…At the plasma membrane, the expression of only TLR2 molecules was determined. The limited expression of TLRs on trophoblast cells suggested that early trophoblasts might be less able to protect embryos against pathogenic agents compared to differentiated trophoblast cells [41]. The obtained results are consistent with outcomes of another study, which indicated that TLR4 expression and related IL-8 secretion that occurred after LPS stimulation might be assigned, rather, to leukocytes, as it was no longer observed in trophoblast fraction purified from leukocytes [42].…”

“…Particularly, significantly higher TLR4 levels were observed in decidual cells of the first and third trimester compared to second trimester basalis, suggesting that an enhanced inflammatory environment occurred at the maternal–fetal interface in the initial stages and end of pregnancy compared to mid-pregnancy [34]. In turn, another study showed the presence of TLR2 and TLR4 proteins expressions from the one-cell stage through the blastocyst stage during murine embryo development [41]. In trophoblast stem cells, the expression of TLR2 and TLR6 but not TLR1 or TLR4 was observed [41].…”

“…In turn, another study showed the presence of TLR2 and TLR4 proteins expressions from the one-cell stage through the blastocyst stage during murine embryo development [41]. In trophoblast stem cells, the expression of TLR2 and TLR6 but not TLR1 or TLR4 was observed [41]. At the plasma membrane, the expression of only TLR2 molecules was determined.…”

Alterations inTLRsas new molecular markers of congenital infections withHuman cytomegalovirus?

“…Similarly, in the case of HCMV infection, a significant role was reported for the same four TLRs (Varani et al, 2007;Iversen et al, 2009;Yew et al, 2010;Yew & Harrison, 2011). Studies showed that TLR alterations at the maternal-fetal interface are involved in innate immunity during gestation, as also observed in the case of HCMV (Chaudhuri et al, 2009) and bacterial infections (Holmlund et al, 2002;Forster-Waldl et al, 2005;Zariffard et al, 2005;Sadeghi et al, 2007;Rose et al, 2011), as well as in the pathogenesis of adverse pregnancy outcomes Ilievski et al, 2007;Ilievski & Hirsch, 2010;Sado et al, 2011;Wujcicka et al, 2013).…”

Differential Toll-Like Receptor (TLR) mRNA Expression Patterns during Chicken Embryological Development

“…Earlier, differential expression of TLR2 and TLR4 in developing fetal sheep lung has been shown (23,24). TLR2 and TLR4 protein were expressed from the first cell stage through the blastocyst stage of murine embryo (25). TLR4, a well known receptor for LPS together with lysozyme, a major protein component of egg known to bind and detoxify LPS (26) may provide protection against major Gram negative bacteria in the event of in ovo infection.…”