miR-451 Deficiency Is Associated with Altered Endometrial Fibrinogen Alpha Chain Expression and Reduced Endometriotic Implant Establishment in an Experimental Mouse Model

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.

Identification of Biomarkers for Endometriosis Using Clinical Proteomics

“…utilized a novel mouse model in which eutopic endometrial fragments used to induce EM were deficient in miR-451 expression, which resulted in fewer ectopic lesions in vivo and was associated with differential expression of alpha polypeptide isoform 2 precursor. [ 21 ] As this polypeptide contained arginyl-glycyl-aspartic acid (RGD) cell adhesion motifs that could modify early-stage lesion development, RGD peptides might help prevent recurrent EM development.…”

Hunting the Needle in the Haystack: A Guide to Obtain Biologically Meaningful MicroRNA Targets

“…Loss-of function experiments may also be implemented by utilizing neutralizing antibodies in case of a secreted protein [ 104 ], or by pharmacological inhibitors of the target of interest [ 105 ]. As for the readout, the same techniques can be applied as were used for showing the miRNA’s effect in the first place (e.g., RT-qPCR for marker genes, Western Blotting, biochemical assays, histological stainings).…”

MiR-183 Regulates ITGB1P Expression and Promotes Invasion of Endometrial Stromal Cells

“…MiR-196b was implicated in HOXA10 expression and in the proliferation of endometriotic stromal cells [ 6 ]. Loss of eutopic endometrial miR-451 expression is associated with decreased establishment of endometriosis in a mouse model [ 7 ]. These data landed strong support for an important role of miRNAs in the development of endometriosis through regulating cell proliferation, cell apoptosis, cell migration, cell invasiveness, and estrogenic signaling.…”