Mirna biogenesis pathway is differentially regulated during adipose derived stromal/stem cell differentiation

Abstract

Stromal/stem cell differentiation is controlled by a vast array of regulatory mechanisms. Included within these are methods of mRNA gene regulation that occur at the level of epigenetic, transcriptional, and/or posttranscriptional modifications. Current studies that evaluate the posttranscriptional regulation of mRNA demonstrate microRNAs (miRNAs) as key mediators of stem cell differentiation through the inhibition of mRNA translation. miRNA expression is enhanced during both adipogenic and osteogenic differentiation; however, the mechanism by which miRNA expression is altered during stem cell differentiation is less understood. Here we demonstrate for the first time that adipose-derived stromal/stem cells (ASCs) induced to an adipogenic or osteogenic lineage have differences in strand preference (-3p and -5p) for miRNAs originating from the same primary transcript. Furthermore, evaluation of miRNA expression in ASCs demonstrates alterations in both miRNA strand preference and 5'seed site heterogeneity. Additionally, we show that during stem cell differentiation there are alterations in expression of genes associated with the miRNA biogenesis pathway. Quantitative RT-PCR demonstrated changes in the Argonautes (AGO1-4), Drosha, and Dicer at intervals of ASC adipogenic and osteogenic differentiation compared to untreated ASCs. Specifically, we demonstrated altered expression of the AGOs occurring during both adipogenesis and osteogenesis, with osteogenesis increasing AGO1-4 expression and adipogenesis decreasing AGO1 gene and protein expression. These data demonstrate changes to components of the miRNA biogenesis pathway during stromal/stem cell differentiation. Identifying regulatory mechanisms for miRNA processing during ASC differentiation may lead to novel mechanisms for the manipulation of lineage differentiation of the ASC through the global regulation of miRNA as opposed to singular regulatory mechanisms.

Altered Regulation of adipomiR Editing with Aging

“…Drosha and Dicer are key enzymes involved in miRNA biogenesis. It is known that Dicer and miRNA biogenesis are essential for the adipogenic differentiation and not osteogenic differentiation of the adipose-derived stem cells [51], however, this function is independent of Dicer's role in preventing growth senescence of primary cells [36]. In the present study, there was a sexual dimorphism in the expression levels of Drosha and Dicer with aging.…”

MicroRNA‑30a regulates chondrogenic differentiation of human bone marrow‑derived mesenchymal stem cells through targeting Sox9

“…miRNAs play an important role in stem cell self-renewal and differentiation as endogenous post-transcriptional regulators (43). Recently, several studies suggested that miRNAs may be involved in MSC chondrogenic differentiation (44–46). During the chondrogenic differentiation of MSCs, various miRNAs display differential expression patterns and can regulate the differentiation process by inhibiting the expression of specific target genes.…”

The importance of cellular and exosomal miRNAs in mesenchymal stem cell osteoblastic differentiation

“…The importance of AGO2 is underscored in the context of erythrogenesis, where AGO2 is solely expressed 13 . The function of AGO2 in stem cell differentiation to the osteogenic lineage is implicated by the alterations in AGO gene expression 14 . Direct investigation of AGO2 function during MSC differentiation has not been reported.…”