miR-130a and miR-27b Enhance Osteogenesis in Human Bone Marrow Mesenchymal Stem Cells via Specific Down-Regulation of Peroxisome Proliferator-Activated Receptor γ

Abstract

Mesenchymal stem cell (MSC) is a type of stem cell that is capable of differentiating into osteoblasts and adipocytes. The pathological perturbation of MSC fate determination is well demonstrated by the replacement of bone tissues with fat in those with osteoporosis and osteopenia. Cell fate determination can be regulated by epigenetic and post-transcriptional mechanisms. MicroRNAs (miRNAs) are small endogenous non-coding RNA molecules that mediates the post-transcriptional regulation of genes expression. We hypothesized that miRNA specified to PPARγ, a major transcription factor of adipogenesis, is responsible for the differentiation of MSCs into osteoblasts. Candidate miRNA that is responsible for target gene inhibition was identified from the miRNA database via bioinformatic analyses. In this study, miR-130a and miR-27b were selected for investigation on their role in specifically binding to peroxisome proliferator-activated receptor γ (PPARγ) via in vitro osteogenesis of human MSCs. During osteogenic differentiation of human MSCs, the expression level of miR-130a and miR-27b were found to be upregulated. In the meanwhile, adipogenic marker genes (PPARγ and C/EBPβ) were found to decrease, which is in contrary to the increased expression of osteogenic marker genes (RUNX2 and Osterix). MSCs were transfected with mimics and inhibitors of miR-130a and miR-27b during in vitro osteogenesis followed by evaluation for the presence of osteogenic markers via quantitative gene expression, Western blot analysis and alkaline phosphatase activity assay. The overexpression of miR-130a and miR-27b is shown to enhance osteogenesis by increasing the gene expression of RUNX2 and Osterix, the protein expression of RUNX2, COL1A1, and Osterix as well as the alkaline phosphatase activity. Taken altogether, these results suggested that miR-130a and miR-27b could promote osteogenesis in human MSCs by targeting the PPARγ.

MicroRNA‐130a controls bone marrow mesenchymal stem cell differentiation towards the osteoblastic and adipogenic fate

“…A study has been undertaken that miR‐130a affects the process of human preadipocyte differentiate into adipocytes . In the recent study, MiR‐130a is believed to promote osteogenesis in human MSCs by targeting the PPARγ . However, no report has been published on the function of miR‐130a in regulating differentiation switch fate of BMSC during ageing.…”

“…41 In the recent study, MiR-130a is believed to promote osteogenesis in human MSCs by targeting the PPARγ. 42 a critical osteoblast-specific transcription factor, which leads to decreasing in osteoblast formation. 39,40 Several studies have clearly demonstrated that PPARγ is highly expressed in early stage of adipogenesis and plays a key role in adipocyte formation.…”

The role and mechanism of exosomes from umbilical cord mesenchymal stem cells in inducing osteogenesis and preventing osteoporosis

“…The core mechanism of microRNAs is to induce mRNA degradation or inhibit the expression of their target genes through complementary pairing with mRNA base sequences, which is a key mechanism of biological processes such as cell differentiation, growth, migration, and apoptosis [7]. Exosomes are carriers of information between cells or tissues; therefore, microRNAs in exosomes play an important role in the regulation of cell function [21].…”

“…Among them, PPARgamma is the key regulator of adipocyte differentiation. In addition, PPARgamma is involved in the pathology of many diseases, including obesity, diabetes, atherosclerosis, and cancer [7]. A study of bone marrow MSCs in the elderly with osteoporosis showed that the osteogenic differentiation ability of MSCs decreases, their ability to differentiate into adipocytes increases, and the osteoclast activity increases.…”

“…For example, MSC-derived exosomes have therapeutic effects on diabetes, renal disease, and ischemic stroke [5,6]. MicroRNAs (miRNAs) are one of the main bioactive substances in exosomes, and comprise endogenous non-coding single-stranded small RNAs (18)(19)(20)(21)(22)(23)(24)(25) nucleotides in length) that regulate gene expression at the post-transcriptional level by binding to the 3' untranslated region (UTR) region of target mRNAs [7]. Experimental studies have con rmed that miRNAs in MSC-derived exosomes play an important role in regulating cell function and treating various diseases [8].…”