The effect of relaxin on the oxytocin receptor in human uterine smooth muscle cells

Relaxin Modulates the Genomic Actions and Biological Effects of Estrogen in the Myometrium

Estradiol (E2) and relaxin (Rln) are steroid and polypeptide hormones, respectively, with important roles in the female reproductive tract, including myometrium. Some actions of Rln, which are mediated by its membrane receptor RXFP1, require or are augmented by E2 signaling through its cognate nuclear steroid receptor, estrogen receptor alpha (ERα). In contrast, other actions of Rln act in opposition to the effects of E2. Here we explored the molecular and genomic mechanisms that underlie the functional interplay between E2 and Rln in the myometrium. We used both ovariectomized female mice and immortalized human myometrial cells expressing wild-type or mutant ERα (hTERT-HM-ERα cells). Our results indicate that Rln modulates the genomic actions and biological effects of estrogen in the myometrium and myometrial cells by reducing phosphorylation of ERα on serine 118 (S118), as well as by reducing the E2-dependent binding of ERα across the genome. These effects were associated with changes in the hormone-regulated transcriptome, including a decrease in the E2-dependent expression of some genes and enhanced expression of others. The inhibitory effects of Rln cotreatment on the E2-dependent phosphorylation of ERα required the nuclear dual-specificity phosphatases DUSP1 and DUSP5. Moreover, the inhibitory effects of Rln were reflected in a concomitant inhibition of the E2-dependent contraction of myometrial cells. Collectively, our results identify a pathway that integrates Rln/RXFP1 and E2/ERα signaling, resulting in a convergence of membrane and nuclear signaling pathways to control genomic and biological outcomes.

Oxytocin Modulates Osteogenic Commitment in Human Adipose-Derived Stem Cells

Human adipose-derived stem cells (hASCs) are commonly harvested in minimally invasive contexts with few ethical concerns, and exhibit self-renewal, multi-lineage differentiation, and trophic signaling that make them attractive candidates for cell therapy approaches. The identification of natural molecules that can modulate their biological properties is a challenge for many researchers. Oxytocin (OXT) is a neurohypophyseal hormone that plays a pivotal role in the regulation of mammalian behavior, and is involved in health and well-being processes. Here, we investigated the role of OXT on hASC proliferation, migratory ability, senescence, and autophagy after a treatment of 72 h; OXT did not affect hASC proliferation and migratory ability. Moreover, we observed an increase in SA-β-galactosidase activity, probably related to the promotion of the autophagic process. In addition, the effects of OXT were evaluated on the hASC differentiation ability; OXT promoted osteogenic differentiation in a dose-dependent manner, as demonstrated by Alizarin red staining and gene/protein expression analysis, while it did not affect or reduce adipogenic differentiation. We also observed an increase in the expression of autophagy marker genes at the beginning of the osteogenic process in OXT-treated hASCs, leading us to hypothesize that OXT could promote osteogenesis in hASCs by modulating the autophagic process.

A possible ambivalent role for relaxin in human myometrial and decidual cells in vitro

PURPOSE

Based on the reported tocolytic action of the hormone relaxin (RLX) in rodents, locally produced in reproductive tissues and the corpus luteum in mammals, the present study aimed to evaluate the influence of RLX on contraction-mediating cyclooxygenases-1 and -2 (COX) and the contractile prostaglandin PGE(2) in human myometrial and decidual cells. Primary cultured cells were obtained from uteri and placentas of term and preterm women undergoing elective caesarean section.

METHODS

In vitro culture of primary myometrial and decidual cells, immunocytochemistry, reverse transcription and real-time PCR, Western blot, ELISA.

RESULTS

We demonstrate for the first time an activating effect of RLX for human COX-1 and COX-2 in primary myometrial and decidual cells in vitro.

CONCLUSIONS

These effects might potentially contribute to birth-associated induction of contractions in vivo.