IADR Abstract Archives
Long Noncoding RNAs In Osteoblastic Differentiation Of Mesenchymal Stem Cells
Objectives: Long noncoding RNAs (lncRNAs) have recently emerged as novel regulators of gene expression. These molecules are critical for lineage commitment, differentiation, organ development, disease progression and organism viability. LncRNAs have these diverse regulatory roles by facilitating epigenetic mechanisms including chromatin looping and histone post-translational modification, as well as directly regulating mRNA splicing, transcription and protein translation. Therefore, lncRNAs have tremendous potential for treating skeletal disorders. Because no studies have been carried out to identify lncRNAs as related to bone formation, we characterized the global expression of lncRNAs in primary mesenchymal stem cells (MSCs) undergoing osteoblastic differentiation.
Methods: Mouse MSC were differentiated to osteoblast lineage and 4 specific stages of maturation were evaluated: day 0 (proliferation), day 7 (commitment), day 14 (extracellular matrix deposition) and day 21 (mineralization). LncRNA sequences enriched in osteoblasts were derived from RNA-Seq profiling. To further validate their dynamic expression during differentiation, the expression profiles were correlated with ChIP-Seq analysis of epigenetic modifications associated with transcriptional activation, elongation and repression (H3K4me3, H3K27ac, H3K36me3, H3K27me). We further examined whether the osteoblast-specific transcription factor Runx2 could be involved in lncRNA transcript expression using ChIP-Seq.
Results: We identified 1612 annotated lncRNAs expressed at significant levels during mMSC osteoblast differentiation, of which 130 were differentially expressed in a stage-specific manner. As with mRNAs, changes in lncRNA expression are reflected at the chromatin level by changes in histone marks. Dynamic changes were observed in a subset of lncRNAs; others were constitutively expressed. Intersection of lncRNAs with enrichment profiles of Runx2 revealed >40% of lncRNAs genomic loci were bound by Runx2.
Conclusions: Our comprehensive dataset identifies over a hundred lncRNAs that are dynamically expressed during osteogenesis, many of which are potentially regulated by Runx2. These findings open novel dimensions for exploring lncRNAs in regulating normal and diseased mineralized tissues.
Methods: Mouse MSC were differentiated to osteoblast lineage and 4 specific stages of maturation were evaluated: day 0 (proliferation), day 7 (commitment), day 14 (extracellular matrix deposition) and day 21 (mineralization). LncRNA sequences enriched in osteoblasts were derived from RNA-Seq profiling. To further validate their dynamic expression during differentiation, the expression profiles were correlated with ChIP-Seq analysis of epigenetic modifications associated with transcriptional activation, elongation and repression (H3K4me3, H3K27ac, H3K36me3, H3K27me). We further examined whether the osteoblast-specific transcription factor Runx2 could be involved in lncRNA transcript expression using ChIP-Seq.
Results: We identified 1612 annotated lncRNAs expressed at significant levels during mMSC osteoblast differentiation, of which 130 were differentially expressed in a stage-specific manner. As with mRNAs, changes in lncRNA expression are reflected at the chromatin level by changes in histone marks. Dynamic changes were observed in a subset of lncRNAs; others were constitutively expressed. Intersection of lncRNAs with enrichment profiles of Runx2 revealed >40% of lncRNAs genomic loci were bound by Runx2.
Conclusions: Our comprehensive dataset identifies over a hundred lncRNAs that are dynamically expressed during osteogenesis, many of which are potentially regulated by Runx2. These findings open novel dimensions for exploring lncRNAs in regulating normal and diseased mineralized tissues.