Epigenetic impact of long non-coding RNA lnc-ADAM9 on extracellular matrix pathway in preterm syndrome through down-regulation of mRNA-ADAM9

Abstract

im: Evidence suggests that the risk of spontaneous preterm birth (sPTB) is the result of environmental exposure interacting with genetic risk and is mediated by epigenetic modification. Long non-coding RNA (lncRNA) comprises a large group of regulators of epigenetic modification that has recently become the focus of increased investigation in reproductive science. Human placenta expresses many lncRNAs, and differential expression profiles (DEPs) have identified several lncRNAs as associated with sPTB. However, little is known about lncRNA’s role in the epigenetic modification of the genes potentially involved in sPTB. This study is to better understand the epigenetic regulation of lncRNA on the development of sPTB. Methods: A transcriptomic analysis of human placentas derived from various pregnancy outcomes was performed as a discovery study. This was followed by a quantitative confirmation to validate the differential transcription of lncADAM9, the lncRNA overlapping with the ADAM9 gene locus, and of lncRNA-overlapped mRNA of ADAM9 (mRNA-ADAM9). In vitro examination of lncADAM9 transgenic (TG) HTR8 cells were used to perform functional assessment to address the role of lncADAM9-mediated epigenetic regulation of extracellular matrix-adhesion (ECM-A) associated molecules. This assessment was then expanded to studies of human fetal membranes. Results: We observed that expression of lncADAM9 was increased in sPTB, and this increase was further associated with the down-regulation of mRNA-ADAM9 in human placentas. In vitro, overexpression of lncADAM9 in lncADAM9-transgenic HRT8 cells led to DEPs relevant to ECM-A molecules, particularly at the loci of CNTN1, NRXN2, SPN, ICAM2, and HLA-DPB1. This was also true in fetal membranes from abnormal versus normal fetal membranes. Conclusion: We have studied the epigenetic impact of differentially expressed lncADAM9 on the ECM-A pathway that is associated with sPTB and documented that this impact may be mediated through the down-regulation of mRNA-ADAM9. Our results of demonstrating the epigenetic regulation of lncADAM9 on the ECM-A pathway may help provide greater insight into critical pathogenic mechanisms underlying sPTB.