Hydroxychloroquine improves pregnancy outcomes by inhibiting excessive autophagy in extravillous trophoblast caused by an anti-phospholipid syndrome.

OBJECTIVES

This study aims to investigate the mechanism of hydroxychloroquine (HCQ) immunoregulation therapy in improving adverse pregnancy outcomes of recurrent miscarriages (RM) caused by antiphospholipid syndrome (APS).

METHODS

(i) Immunofluorescence staining was used to analyse the potential targets of antiphospholipid antibodies at the maternal-fetal interface in normal early pregnancy; (ii) Immunohistochemical and immunofluorescence techniques were used to compare and analyse the placenta vascular remodeling, villus tissue synthetic secretion function, trophoblastic autophagy and apoptosis levels in first trimester decidual tissue between normal and APS caused recurrent miscarriages (APS-RM) cases; (iii) HTR8/SVneo and BeWo cell lines were treated with serum from normal and APS-RM cases, and quantified by RT-PCR and Western blot to analysis the expression levels of cell invasion, secretion, autophagy and apoptosis-related molecules; (iv) After adding 0.1 μg/ml HCQ to the serum-treated cell line, the expression of autophagy and invasion-related proteins were detected, and invasion and tube formation of HTR8/SVneo cells was assessed by transwell experiments and tube formation assay.

RESULTS

(i)β2-glycoprotein Ⅰ antigen is expressed in all types of trophoblasts at the maternal-fetal interface in first trimester; (ii) The extravillous trophoblast cells (EVTs) have excessive autophagy in the decidual tissue of the APS-RM cases, and the uterine spiral artery was remodelled insufficiently; (iii) APS-RM cases serum can lead to cell excessive autophagy, and decrease cell invasion and tube formation in vitro; (iv) 0.1 μg/ml HCQ could rescue abnormal cell status caused by APS cases serum in HTR8/SVneo cells in vitro; (v) APS cases serum mainly affects the invasion and tube formation of EVTs, but has little effect on the function of villous trophoblast cells.

CONCLUSIONS

Antiphospholipid antibodies can lead to excessive autophagy in EVTs, thereby affecting ability of invasion and remodeling of spiral arteries, which is one of the mechanisms leading to adverse pregnancy outcomes. HCQ can rescue adverse pregnancy outcomes in APS patients by inhibiting excessive autophagy.