Endoplasmic Reticulum Stress through ATF6a pathway is associated with an inflammatory response in endometrial stromal cells: potential regulation by miRNAs

MIRANDA, LUCAS; GRASSO, ESTEBAN; MARTÍ, MARCELO; CLAUDIA PÉREZ LEIRÓS; MURRIETA-COXCA, JOSÉ MARTÍN; GALLINO, LUCILA; GORI, SOLEDAD; FAVARO, RODOLFO; ROSANNA RAMHORST; SOCZEWSKI, ELIZABETH; GUTIERREZ-SAMUDIO, RUBY; LAURA FERNANDEZ; MORALES-PRIETO, DIANA; MARKERT, UDO

Congreso; SCHCF+ALAF 2020 Joint meeting; 2020

Introduction: During decidualization, endometrial stromal cells undergo endoplasmic reticulumstress (ERS) and unfolded protein response (UPR), which will allow them to expand theirendoplasmic reticulum with the corresponding machinery for protein folding. These processes aredirected by miRNAs that regulate the expression or stability of their transcription factors.Objectives: we focus on the role of ERS/UPR during decidualization to induce a physiologicalsterile inflammatory response and whether it might be regulated by miRNAs.Methods: We used an in vitro model of decidualization represented by human telomeraseimmortalized endometrial stromal cell line St-T1b ; and endometrial biopsies from patients with recurrent spontaneous abortions (RSA) and recurrent in vitro fertilization failures (RIF). Statistical analysis: Student?s t test. Mean±S.E.M. of at least 4 independent experiments. The study was approved by the respective local ethic committee (Friederich Schiller Universität).Results: We evaluated the expression of the ERS-sensor ATF6 and the UPR marker, CHOP.Both markers increased in decidualized cells, and Tg (ERS inducer) induced even higher levels incomparison with non-decidualized cells. Then, we evaluated the modulation of TXNIP, a linkbetween the ERS-pathway and inflammation. TXNIP increased in decidualized cells, and also theinflammasome NLRP3 and IL-1b expression. Then, using an in silico analysis using miRTarBasev8.0 we selected two miRNAs able to regulate the ERS and UPR pathways: miR-193b-3p and miR-21-5p. Both miRNAs significantly decreased in non-decidualized cells in the presence of Tg.Finally, we studied the expression and localization of miRNAs through an In Situ Hybridization(ISH) technique in endometrial samples. Both miRNAs were expressed in stromal cells andendometrial glands in samples from RSA and RIF patients at similar levels.Conclusion:The present results suggest that decidualization in St-T1b cells is accompanied by anERS and UPR associated with a sterile inflammatory response potentially regulated by miR-193b-3p and miR-21-5p.We acknowledge DAAD for financial support of Elizabeth Soczewski´s short?term stay in Placenta-Labor. This work was funded by Deutsche Forschungsgemeinschaft and the National Agency ofSciences and Technology from Argentina.