Proteoglycan macromolecules play key roles in several physiological processes (e.g.,
adhesion, proliferation, migration, invasion, angiogenesis, and apoptosis), all of
which are important for placentation and healthy pregnancy. However, their precise
roles in human reproduction have not been clarified. To fill this gap, herein, we
provide an overview of the proteoglycans' expression and role in the placenta, in
trophoblast development, and in pregnancy complications (pre-eclampsia, fetal growth
restriction), highlighting one of the most important members of this family, syndecan-1
(SDC1). Microarray data analysis showed that of 34 placentally expressed proteoglycans,
SDC1 production is markedly the highest in the placenta and that SDC1 is the most
upregulated gene during trophoblast differentiation into the syncytiotrophoblast.
Furthermore, placental transcriptomic data identified dysregulated proteoglycan genes
in pre-eclampsia and in fetal growth restriction, including SDC1, which is supported
by the lower concentration of syndecan-1 in maternal blood in these syndromes. Overall,
our clinical and in vitro studies, data analyses, and literature search pointed out
that proteoglycans, as important components of the placenta, may regulate various
stages of placental development and participate in the maintenance of a healthy pregnancy.
Moreover, syndecan-1 may serve as a useful marker of syncytialization and a prognostic
marker of adverse pregnancy outcomes. Further studies are warranted to explore the
role of proteoglycans in healthy and complicated pregnancies, which may help in diagnostic
or therapeutic developments.
