A program of microRNAs controls osteogenic lineage progression by targeting transcription factor Runx2

Abstract

Lineage progression in osteoblasts and chondrocytes is stringently controlled by the cell-fate-determining transcription factor Runx2. In this study, we directly addressed whether microRNAs (miRNAs) can control the osteogenic activity of Runx2 and affect osteoblast maturation. A panel of 11 Runx2-targeting miRNAs (miR-23a, miR-30c, miR-34c, miR-133a, miR-135a, miR-137, miR-204, miR-205, miR-217, miR-218, and miR-338) is expressed in a lineage-related pattern in mesenchymal cell types. During both osteogenic and chondrogenic differentiation, these miRNAs, in general, are inversely expressed relative to Runx2. Based on 3′UTR luciferase reporter, immunoblot, and mRNA stability assays, each miRNA directly attenuates Runx2 protein accumulation. Runx2-targeting miRNAs differentially inhibit Runx2 protein expression in osteoblasts and chondrocytes and display different efficacies. Thus, cellular context contributes to miRNA-mediated regulation of Runx2. All Runx2-targeting miRNAs (except miR-218) significantly impede osteoblast differentiation, and their effects can be reversed by the corresponding anti-miRNAs. These findings demonstrate that osteoblastogenesis is limited by an elaborate network of functionally tested miRNAs that directly target the osteogenic master regulator Runx2.osteogenesis | chondrogenesis | post-transcriptional regulation C ell-fate determination and subsequent lineage progression of phenotype-committed cells are mediated by master regulatory transcription factors that integrate multiple cell-signaling inputs and generate epigenetic changes in chromatin to modulate gene expression. Transcription factors are components of positive and negative feedback loops that initiate or maintain the acquisition of distinct biological states. Epigenomic mechanisms, including attenuation of mRNA and protein expression by small noncoding microRNAs (miRNAs) (1), permit effective control of gene expression beyond genomic interactions between transcription factors and their cognate elements in gene promoters. The biological potency of miRNAs, which are generated by the RNA processing enzyme Dicer, is based on their ability to control mRNA accumulation and/or protein synthesis through specific interactions with the 3′UTRs of target genes (1). Gene regulatory networks involving transcription factors and miRNAs may mutually reinforce cell fates and support phenotypic maturation of lineage-committed cells.Osteogenic differentiation provides an effective cell model in which to define both epigenetic and epigenomic mechanisms required for cell-fate determination and phenotypic differentiation. Differentiation of multipotent mesenchymal stem cells into the osteoblast lineage and maturation of osteoprogenitors are controlled by multiple extracellular ligands [e.g., BMPs, WNTs, and FGFs] (2-4) that direct the activities of key transcription factors, including Runx2, Osterix, and different classes of homeodomain proteins (5-8). Runx2 is a critical regulator of the osteogenic lineage, and its epigenetic functions modulate ...

MicroRNA-204 Targets Runx2 to Attenuate BMP-2-induced Osteoblast Differentiation of Human Aortic Valve Interstitial Cells

“…These findings corresponded well with the proposed role of miR-204, which regulates cellular transition in multiple cell types. 15,28,29 Recently, Runx2 has been reported to be closely associated with the osteoblast differentiation of VICs in aortic valve calcification. 30,31 Moreover, reactive oxygen species induces the expression of Runx2 through AKT signaling pathway, leading to activation of VICs toward an osteogenic-like phenotype.…”

Expression of microRNAs during chondrogenesis of human adipose-derived stem cells

“…Analysis of the growth plates in transgenic mice and in chick limbs showed that Runx2 promoted chondrogenesis either by maintaining or by initiating early chondrocyte differentiation 34 . Furthermore, Runx2 regulated differentiation of MSCs as the target of miRNAs 48,49 . Moreover, C/EBPb could enhance the activity of Runx2 50 .…”

Circulating microRNAs signature correlates with positive [18F]fluorodeoxyglucose-positron emission tomography in patients with abdominal aortic aneurysm

“…Modifications of miR-125b-5p level have been involved in arterial calcification by smooth muscle cells 37 by regulating their transdifferentiation into osteoblast-like cells through the regulation of SP7 and RUNX2, 36 a marker of osteogenesis also found to be involved in arterial calcification. 38,39 MiR-204-5p also directly targets RUNX2. Five other target genes were found to be common between both miRNAs, including HAPLN1, an extracellular matrix protein interacting with proteoglycans and involved in cartilage development.…”