lncRNAs are associated with polysomes during adipose-derived stem cell differentiation.

Over the past few years, an increasing number of long noncoding RNAs (lncRNAs) have been identified in mammalian genomes. Most of these lncRNAs are expressed at low levels in different human cell types. lncRNAs are found not only in the nucleus but are also enriched in the cytosolic fraction and are associated with translating polysomes. Expression of lncRNAs that have putative roles in cell differentiation has been identified in embryonic and adult stem cells. Nevertheless, the mechanisms by which lncRNAs operate in the cell are still poorly understood.Here, we studied the expression of the subpopulation of lncRNAs that are associated with polysomes in adipose-derived stem cells (hASCs) during their commitment to adipocytes. We established that lncRNAs and protein coding genes have similar expression levels. The relatively comparable expression of these transcripts could be a particular feature of hASCs. We then show that lncRNAs are associated with polysomes in undifferentiated and early differentiating cells, which was confirmed by quantitative RT-PCR. The association of lncRNAs with polysomes was also comparable to that of mRNAs. Our results suggest that the presence of lncRNAs in the polysomal RNA fraction is not the result of random association. We observed that a high percentage of lncRNAs are actively mobilized to or from polysomes during early stages of adipogenesis. Moreover, we found several lncRNAs that can potentially target miRNAs relevant to adipogenesis.