Insufficient invasion of conceptus-derived trophoblast cells in the maternal decidua is a key event in the development of early-onset preeclampsia (PE), a subtype of PE associated with high maternal and fetal morbidity and mortality. Kisspeptins, a family of peptides previously shown to inhibit trophoblast cell invasion, have been implicated in the pathogenesis of early-onset PE. However, a role of kisspeptin signaling during the genesis of this syndrome has not been elucidated. Herein, we used the preeclamptic-like BPH/5 mouse model to investigate kisspeptin expression and potential upstream regulatory mechanisms in a PE-like syndrome. Expression of the kisspeptin encoding gene, Kiss1, and the 10-amino-acid kisspeptide (Kp-10), are upregulated in the non-pregnant uterus of BPH/5 females during diestrus and in the maternal-fetal interface during embryonic implantation and decidualization. Correspondingly, the dysregulation of molecular pathways downstream to kisspeptins also occurs in this mouse model. BPH/5 females have abnormal sex steroid hormone profiles during early gestation. In this study, the normalization of circulating concentrations of 17β-estradiol (E2) and progesterone (P4) in pregnant BPH/5 females not only mitigated Kiss1 upregulation, but also rescued the expression of multiple molecules downstream to kisspeptin and ameliorated adverse fetoplacental outcomes. Those findings suggest that uterine Kiss1 upregulation occurs pre-pregnancy and persists during early gestation in a PE-like mouse model. Moreover, this study highlights the role of sex steroid hormones in uteroplacental Kiss1 dysregulation and the improvement of placentation by normalization of E2, P4 and Kiss1.

Placentitis is the leading cause of infectious abortion in the horse. Additionally, it can result in weak and/or growth restricted offspring. While the etiology of ascending placentitis is well described in mares, less is known regarding the pathogenesis of other types, such as nocardioform placentitis. This study aims to identify the microbial communities in different body sites of the pregnant mare in early gestation to establish a core microbiome that may be perturbed in pathologic pregnancies such as placentitis. We hypothesize that the equine placenta harbors a distinct resident microbiome in early pregnancy when characterized by metagenetics and that there will be a disparity in bacterial communities from the oral, vaginal, and fecal microbiome. Samples were collected from the oral cavity, vagina, anus, and the allantoic portion of the allantochorion (“placenta”) from five pregnant mares between 96 and 120 days of gestation. The V4 region of the 16S rRNA gene was amplified for Illumina MiSeq sequencing to examine core bacterial communities present in the different body sites. Microbial community composition of the pregnant ponies by body site was significantly different (Bray–Curtis dissimilarity). The placenta was significantly different from the feces, oral cavity, and vagina. Alpha diversity measuring the Shannon diversity matrix was significant, with the body sites being a compounding variable, meaning there was a difference in richness and evenness in the different microbial communities. Feces had the greatest alpha diversity, while the oral cavity and placenta similarly had the least. In conclusion, metagenetics did reveal distinct community differences in the oral, fecal, vaginal, and placenta cavities of the horse. The equine placenta does show similarities in its microbial communities to the oral cavity. Further research needs to be completed to investigate how bacteria may be translocated to the placenta from these other body sites and how they contribute to the development of placentitis.

Preeclampsia (PE) is a devastating hypertensive disorder of pregnancy closely linked to obesity. Long-term adverse outcomes may occur in offspring from preeclamptic pregnancies. Accordingly, sex-specific changes in pubertal development have been described in children from preeclamptic women, but the underlying mechanisms remain vastly unexplored. Features of PE are spontaneously recapitulated by the blood pressure high subline 5 (BPH/5) mouse model, including obesity and dyslipidemia in females before and throughout pregnancy, superimposed hypertension from late gestation to parturition and fetal growth restriction. A sexually dimorphic cardiometabolic phenotype has been described in BPH/5 offspring: while females are hyperphagic, hyperleptinemic, and overweight, with increased reproductive white adipose tissue (rWAT), males have similar food intake, serum leptin concentration, body weight and rWAT mass as controls. Herein, pubertal development and adiposity were further investigated in BPH/5 progeny. Precocious onset of puberty occurs in BPH/5 females, but not in male offspring. When reaching adulthood, the obese BPH/5 females display hypoestrogenism and hyperandrogenism. Kisspeptins, a family of peptides closely linked to reproduction and metabolism, have been previously shown to induce lipolysis and inhibit adipogenesis. Interestingly, expression of kisspeptins (Kiss1) and their cognate receptor (Kiss1r) in the adipose tissue seem to be modulated by the sex steroid hormone milieu. To further understand the metabolic-reproductive crosstalk in the BPH/5 offspring, Kiss1/Kiss1r expression in male and female rWAT were investigated. Downregulation of Kiss1/Kiss1r occurs in BPH/5 females when compared to males. Interestingly, dietary weight loss attenuated circulating testosterone concentration and rWAT Kiss1 downregulation in BPH/5 females. Altogether, the studies demonstrate reproductive abnormalities in offspring gestated in a PE-like uterus, which appear to be closely associated to the sexually dimorphic metabolic phenotype of the BPH/5 mouse model.

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Kisspeptins (KP), encoded by Kiss1 , are reported to play a role in early-onset preeclampsia (ePE), a life-threatening hypertensive disorder of pregnancy. KP is higher in term ePE placentae than in normal pregnancies. However, the role of KP in PE has not been confirmed. The Blood Pressure High Subline 5 (BPH/5) mouse model spontaneously develops the main features of ePE, including impaired placental expansion and maternal hypertension. We have shown that Kiss1 is higher at the BPH/5 maternal-fetal interface on embryonic days (e) 4.5 and 7.5. BPH/5 females have abnormal circulating sex steroid hormones (SSH) during early gestation (e2.5), with lower estradiol-17ß (E2) and higher progesterone (P4). Since E2 and P4 may modulate uterine Kiss1 , we aimed to investigate the effects of artificial synchronization of SSH (AS-SSH) in BPH/5 uteroplacental KP signaling and placental development. We hypothesized that AS-SSH would prevent BPH/5 uteroplacental Kiss1 upregulation and normalize KP downstream expression of tissue inhibitor of metalloproteinase (TIMP) 2 and placental defects. AS-SSH was performed after ovariectomy of pregnant BPH/5 and C57 females (n = 8/strain) at e2.5 with one dose of E2 (25 ng/mouse, subcutaneously), and daily subcutaneous injections of P4 (1ng/mouse) until embryonic implantation sites (eIS) were collected 3 days post-surgery (n = 8/group). Contrary to natural (Nat) BPH/5 pregnancies, eIS Kiss1 and TIMP2 expression was not different between AS-SSH BPH/5 and C57 (p > 0.05). Nat and AS-SSH pregnant mice were anesthetized at e12.5 to assess umbilical cord blood flow via ultrasound and uteroplacental units were harvested for placental morphometry (n = 4-6/group). Placental expansion into the maternal decidua was measured and expressed as the ratio of the placenta depth in relation to the placenta + decidua. Nat BPH/5 had lower placental expansion and umbilical blood flow than Nat C57, whereas AS-SSH BPH/5 had higher placental expansion and umbilical blood flow than Nat BPH/5 (p < 0.05). In conclusion, synchronization of the E2 and P4 profile in the BPH/5 mouse early gestation mitigated Kiss1 and TIMP2 upregulation at the maternal-fetal interface and ameliorated the placental defects previously reported in this model.