MiR-451 deficiency is associated with altered endometrial fibrinogen alpha chain expression and reduced endometriotic implant establishment in an experimental mouse model.

Warren B Nothnick,Mitchell J Weiss,Amanda Graham,Joshua Holbert,Shannon M Hawkins

doi:10.1371/journal.pone.0100336

Warren B Nothnick, Mitchell J Weiss + Show 3 more

Open Access

https://doi.org/10.1371/journal.pone.0100336

Copy DOI

Abstract

Endometriosis is defined as the growth of endometrial glandular and stromal components in ectopic locations and affects as many as 10% of all women of reproductive age. Despite its high prevalence, the pathogenesis of endometriosis remains poorly understood. MicroRNAs, small non-coding RNAs that post-transcriptionally regulate gene expression, are mis-expressed in endometriosis but a functional role in the disease pathogenesis remains uncertain. To examine the role of microRNA-451 (miR-451) in the initial development of endometriosis, we utilized a novel mouse model in which eutopic endometrial fragments used to induce endometriosis were deficient for miR-451. After induction of the disease, we evaluated the impact of this deficiency on implant development and survival. Loss of miR-451 expression resulted in a lower number of ectopic lesions established in vivo. Analysis of differential protein profiles between miR-451 deficient and wild-type endometrial fragments revealed that fibrinogen alpha polypeptide isoform 2 precursor was approximately 2-fold higher in the miR-451 null donor endometrial tissue and this elevated expression of the protein was associated with altered expression of the parent fibrinogen alpha chain mRNA and protein. As this polypeptide contains RGD amino acid “cell adhesion” motifs which could impact early establishment of lesion development, we examined and confirmed using a cyclic RGD peptide antagonist, that endometrial cell adhesion and endometriosis establishment could be respectively inhibited both in vitro and in vivo. Collectively, these results suggest that the reduced miR-451 eutopic endometrial expression does not enhance initial establishment of these fragments when displaced into the peritoneal cavity, that loss of eutopic endometrial miR-451 expression is associated with altered expression of fibrinogen alpha chain mRNA and protein, and that RGD cyclic peptide antagonists inhibit establishment of endometriosis development in an experimental mouse model suggesting that this approach may prove useful in the prevention of endometriosis establishment and survival.

Highlights

Ectopic growth of endometrial stromal and glandular tissue outside of the uterine cavity occurs in approximately 10% of all reproductive age women, frequently causing pain, dysmenorrhea and infertility [1,2]
Based upon the initial demonstration that miR-451 expression was reduced in eutopic endometrium from women with endometriosis, coupled with the postulated factors which miR-451 may regulate and their role in endometriosis establishment, we hypothesized that the reduced miR-451 expression by eutopic endometrium may enhance the ability of this displaced endometrial tissue to establish ectopically and develop into endometriosis
Based upon an initial report by Pan and colleagues [9] which suggested that miR-451 expression in eutopic endometrium is significantly reduced compared to eutopic endometrium from women free of endometriosis, coupled with the belief that miR-451 regulates many factors which may play a role in the initial establishment of retrogradely shed endometrial fragments into endometriosis, we set out to determine if the level of eutopic endometrial tissue miR-451 expression influenced the ability of this tissue to establish ectopically

Summary

Introduction

Ectopic growth of endometrial stromal and glandular tissue outside of the uterine cavity (endometriosis) occurs in approximately 10% of all reproductive age women, frequently causing pain, dysmenorrhea and infertility [1,2]. The disease is thought to develop via retrograde release of viable endometrial tissue into the peritoneal cavity during menstruation. This process occurs in most unaffected women [3,4], and it is postulated that additional factors contribute to the pathogenesis of endometriosis. MiRNA profiles have been established for endometriosis in both the disease tissue and eutopic endometrium from these as well as control patients without endometriosis [9,10,11,12]. In the initial report by Pan and colleagues [9], miR-451 expression was shown to be one of the most significantly reduced (by approximately 50%) miRNAs in eutopic

Methods

Results

Conclusion