Global MicroRNA Profiling Uncovers miR-206 as a Negative Regulator of Hematopoietic Commitment in Human Pluripotent Stem Cells

Advanced Analysis and Validation of a microRNA Signature for Fanconi Anemia

Some years ago, we reported the generation of a Fanconi anemia (FA) microRNA signature. This study aims to develop an analytical strategy to select a smaller and more reliable set of molecules that could be tested for potential benefits for the FA phenotype, elucidate its biochemical and molecular mechanisms, address experimental activity, and evaluate its possible impact on FA therapy. In silico analyses of the data obtained in the original study were thoroughly processed and anenrichment analysis was employed to identify the classes of genes that are over-represented in the FA-miRNA population under study. Primary bone marrow mononuclear cells (MNCs) from sixFA patients and sixhealthy donors as control samples were employed in the study. RNAs containing the small RNA fractions were reverse-transcribed and real-time PCR was performed in triplicate using the specific primers. Experiments were performed in triplicate.The in-silico analysis reported six miRNAs as likely contributors to the complex pathological spectrum of FA. Among these, three miRNAs were validated by real-time PCR. Primary bone marrow mononuclear cells (MNCs) reported a significant reduction in the expression level of miRNA-1246 and miRNA-206 in the FA samples in comparison to controls.This study highlights several biochemical pathways as culprits in the phenotypic manifestations and the pathophysiological mechanisms acting in FA. A relatively low number of miRNAs appear involved in all these different phenotypes, demonstrating the extreme plasticity of the gene expression modulation. This study further highlights miR-206 as a pivotal player in regulatory functions and signaling in the bone marrow mesenchymal stem cell (BMSC) process in FA. Due to this evidence, the activity of miR-206 in FA deserves specific experimental scrutiny. The results, here presented, might be relevant in the management of FA.

Ghrelin promotes the osteogenic differentiation of rMSCs via miR-206 and the ERK1/2 pathway

OBJECTIVE

Mesenchymal stem cells (MSCs) can differentiate into chondroblasts, adipocytes, or osteoblasts under appropriate stimulation. Ghrelin, an endogenous ligand for the growth hormone secretagogue receptor (GHSR), stimulates growth hormone (GH) secretion and exerts both orexigenic and adipogenic effects. The ERK1/2 signaling pathway is known to trigger osteogenic differentiation of rabbit bone marrow-derived mesenchymal stromal cells. In the present study, the function of miR-206 in the ghrelin-mediated osteogenic differentiation of rabbit bone marrow-derived mesenchymal stromal cells (rMSCs) was explored.

METHODS

The expression of miR-206 was detected by qPCR, and phosphorylated ERK1/2 and the protein expression levels of ALP, RUNX2, and Osterix were assessed by western blotting.

RESULTS

Ghrelin inhibited the expression of miR-206 to promote the osteogenic differentiation of rMSCs. Moreover, ghrelin increased the phosphorylation of ERK1/2, while overexpression of miR-206 suppressed ERK1/2 phosphorylation, indicating that miR-206 can regulate the ERK1/2 pathway. Further, inhibition of ERK1/2 had no influence on miR-206 expression; however, the phosphorylation of ERK1/2 was decreased, and the protein expression levels of ALP, RUNX2, and Osterix were downregulated.

CONCLUSIONS

Ghrelin promotes the osteogenic differentiation of rMSCs via miR-206 and the ERK1/2 pathway.