329 - The Inhibition of STAT3 Pathways by an Allosteric Modulator of IL-6R, HSJ633, Prevent Preterm Birth

Poster Number: 329
Publication Number: 329.439

France Côté, Université de Montréal, Montréal, PQ, Canada; Elizabeth Prairie, Sainte-Justine Research Center, Montreal, PQ, Canada; Laurence Gobeil, Universite de Sherbrooke Faculty of Medicine, Cowansville, PQ, Canada; Tiffany Habelrih, CHU Sainte-Justine, Montreal, PQ, Canada; Sarah-Eve Loiselle, Universite de Montreal Faculty of Medicine, Montreal, PQ, Canada; Xin Hou, CHU Ste-Justine, Saint-Laurent, PQ, Canada; Christiane Quiniou, Université de Montreal, Montreal, PQ, Canada; Sylvain Chemtob, University of Montreal, Montreal, PQ, Canada

Background: Preterm birth (PTB) is one of the main causes of neonatal mortality and morbidity. Current studies have shown that neonate morbidity in PTB is linked to increased levels of IL-6 in amniotic fluid, fetal blood and gestational tissues (GT) and that IL-6 increases uterine activating proteins (UAP) expression leading to PTB. A small peptide, HSJ633, developed in our lab, selectively inhibits IL-6-induced STAT3 phosphorylation and LPS-induced PTB in mice.

Objective: We hypothesize that IL-6 induces damages to fetal tissues, and that inhibiting the IL-6 receptor using our nanopeptide, HSJ633, will improve birth outcome and maintain the integrity of fetal tissues.

Design/Methods: CD1 pregnant mice were injected with LPS (10μg/kg i.p.) at gestational day (GD) 16 in presence or absence of HSJ633 (1mg/kg/12h), Tocilizumab (TOC; 10mg/kg/12h), Anti-mouse IL-6R (800μg/kg/12h) or vehicle. Prematurity and fetal mortality and morbidity rates were evaluated. Furthermore, HEK-Blue IL-6 cells were treated with IL-6 (0.1μg/ml) in presence or absence of HSJ633 (1μg/ml) and TOC to determine the activation of signaling pathways by Western Blot. In addition, we injected FITC-HSJ633 (1mg/kg/12h) in our PTB murine model at GD18 and tissues (placenta and fetus) were collected 4h post-injection. Fluorescence was evaluated to determine HSJ633’s localization. The analysis conducted on the fetus is ongoing.

Results: HSJ633 improved birth outcome by increasing neonatal survival (p < 0.05) and neonatal weight (p < 0.05) compared to LPS. We then investigated the mechanism of action of HSJ633 in HEK-Blue IL-6 cells treated with IL-6 and HSJ633. We demonstrated that HSJ633 reduced the activation of STAT3 by 100% (p < 0.05) but not p38, AKT, and ERK. In addition, the injection of a STAT3 inhibitor in a LPS-induced PTB mouse model reduced PTB by over 50%. Fluorescence analysis of HSJ633-FITC revealed its presence in the placenta on both fetal and maternal sides in presence of inflammation (LPS induction) (p < 0.05).Conclusion(s): Collectively, our data shows that HSJ633 antagonized the activity of IL-6R in a LPS-induced PTB model by inhibiting STAT3 activation and improved birth outcome. We demonstrated that HSJ633 is found in the placenta only in presence of inflammation. These findings highlight the importance of IL-6 in PTB and uncover in vivo pharmacological efficacy of a novel IL-6R modulator. HSJ633 is a promising new therapeutic prototype in the prevention of PTB.
CV - France CôtéCôté-France EN.pdf