Mouse pregnancy-specific glycoproteins: tissue-specific expression and evidence of association with maternal vasculature

Abstract

The pregnancy-specific glycoproteins (Psg) are secreted hormones encoded by multiple genes in rodents and primates, and are thought to act as immune modulators. The only Psg receptor identified is CD9, through which Psg17 induces cytokine production from macrophages cultured in vitro. We examined temporal and spatial aspects of Psg and CD9 expression during mouse pregnancy to determine whether their expression patterns support a role in immune modulation. Using in situ hybridisation, immunohistochemistry and RT-PCR we found Psg expression in trophoblast giant cells and in the spongiotrophoblast. Psg22 is the predominant Psg family member expressed in giant cells. Detectable Psg is associated predominantly with endothelial cells lining vascular channels in the decidua, rather than with maternal immune cell markers. CD9 expression exhibited partial overlap with Psg, but without exclusive co-localisation. CD9 was observed in decidual cells surrounding early implantation sites, and in the endometrium. However, embryo transfer of wild-type embryos to CD9-deficient females indicates that maternal CD9 is not essential for successful pregnancy.

Intrauterine calorie restriction affects placental DNA methylation and gene expression

“…Pregnancy-specific glycoproteins are postulated to have an immunomodulatory role in protecting the fetal allograft, as well as a role in promoting maternal angiogenesis to support the fetus. Lower levels of pregnancy-specific glycoproteins have been associated with IUGR, fetal hypoxia, and increased risk for abortion, thus providing a link to the CR-associated IUGR phenotype (58,59). Among the 21 apolipoproteins sequenced, eight were upregulated in the CR condition, with the remaining 13 expressed equally in both conditions (enrichment test: P value Ͻ 0.0001).…”

The embryonic stress response to in vitro culture: insight from genomic analysis

“…Galectin 3 (LGASL3) promotes embryo implantation by regulating endometrial cell proliferation and adhesion through interaction with integrin β3 (Yang et al 2011), but oversecretion of Gal-3 is detrimental to trophoblast invasion. The receptivity of the human endometrium to blastocyst adhesion during the pre-implantation window depends in part on signal recognition via membrane domains rich in tetraspanin CD9, a receptor of pregnancy-specific glycoproteins (Wynne et al 2006, Dominguez et al 2010. Overexpression of CD9 in blastocysts could inhibit implantation by reducing embryo invasiveness (Liu et al 2006).…”

Imprinted genes in mouse placental development and the regulation of fetal energy stores

“…These glycogen stores are thought to provide a source of energy for late-gestation embryonic growth and parturition (Coan et al 2006). In contrast, the spongiotrophoblast cells, which form the bulk of the junctional zone, are thought to perform an endocrine role in synthesising and secreting a range of prolactin-related (Prl) proteins and pregnancy-specific glycoproteins (Psgs) that act to modulate maternal physiology in response to pregnancy (Kromer et al 1996, Wynne et al 2006, Simmons et al 2008b). …”