Abnormal trophoblast invasion in early onset preeclampsia: involvement of cystathionine β-synthase, specificity protein 1 and miR-22

Introduction Impaired trophoblast invasion has been observed in early onset Preeclampsia patients (EOPE). Trophoblast cell invasion during human placentation is majorly regulated by the balance between MMPs 2, 9 and their inhibitors [tissue inhibitors of matrix metalloproteinases (TIMPs 1, 2)]. Exogenous NaHS (hydrogen sulphide donor) treatment was shown to significantly increase the expression levels of matrix metalloproteinases (MMPs 2, 9) in human bladder cancer EJ cells. Epigentically, the gene expression of hydrogen sulphide synthesising enzyme CBS (cystathionine β-synthase) could be further regulated by various mi-RNAs via the transcription factors like Sp1. Specificity protein 1 (Sp1) has been identified as a target gene for miR-22 to regulate the invasion and metastasis of gastric cancer cells. However, the mechanism of MMPs regulation by either CBS, Sp1 and miRNA-22 in the pregnancies having EOPE is not known. Aims and Objectives To determine and compare the expression of MMPs 2, 9, TIMPs 1, 2, CBS, Sp1 and miRNA-22 in EOPE patients and normotensive, non-proteinuric controls. Materials and methods 100 pregnant women were enrolled from Department of Obstetrics and Gynaecology, AIIMS, New Delhi, India. EOPE women (n=50) after clinical diagnosis as per ACOG guidelines were enrolled as cases and normotensive, non-proteinuric pregnant women (n=50) were enrolled as controls. Protocol of the study was approved by Institute Ethics Committee, AIIMS, New Delhi. 5 ml of venous blood was collected from all the recruited women (2.5 ml in each EDTA and sera vial) followed by plasma and sera separation. Plasma samples were used subsequently to determine gene expression of MMPs 2, 9, TIMPs 1, 2, CBS, Sp1 and miRNA-22 by qRT-PCR and sera samples were used to estimate their protein levels by ELISA. Data were analyzed by STATA 14 and Graph Pad Prism 8. Results Significantly down regulated expression of MMPs 2, 9, CBS and Sp1 whereas up regulated expression for that of TIMPs 1, 2 was observed in EOPE patients as compared to healthy pregnant women at both transcription and translation levels. Expression of miR-22 (pre miR-22 and miR-22-3p) was found to be significantly elevated in EOPE patients as compared to normotensive, non-proteinuric controls. Conclusion This is the very first study of its kind which implicates that down regulated MMPs 2, 9, CBS, Sp1 levels and simultaneously upregulation of miR-22 expression in EOPE patients could have some association. In vitro experiments are needed to prove their association which if proven may provide a new, potential therapeutic target to treat early onset Preeclampsia.