LINC01638 sustains human mesenchymal stem cell self-renewal and competency for osteogenic cell fate

Abstract

The skeleton forms from multipotent human mesenchymal stem cells (hMSCs) competent to commit to specific lineages. Long noncoding RNAs (lncRNAs) have been identified as key epigenetic regulators of tissue development. However, regulation of osteogenesis by lncRNAs as mediators of commitment to the bone phenotype is largely unexplored. We focused on LINC01638, which is highly expressed in hMSCs and has been studied in cancers, but not in regulating osteogenesis. We demonstrated that LINC01638 promotes initiation of the osteoblast phenotype. Our findings reveal that LINC01638 is present at low levels during the induction of osteoblast differentiation. CRISPRi knockdown of LINC01638 in MSCs prevents osteogenesis and alkaline phosphatase expression, inhibiting osteoblast differentiation. This resulted in decreased MSC growth rate, accompanied by double-strand breaks, DNA damage, and cell senescence. Transcriptome profiling of control and LINC01638-depleted hMSCs identified > 2000 differentially expressed mRNAs related to cell cycle, cell division, spindle formation, DNA repair, and osteogenesis. Using ChIRP-qPCR, molecular mechanisms of chromatin interactions revealed the LINC01638 locus (Chr 22) includes many lncRNAs and bone-related genes. These novel findings identify the obligatory role for LINC01638 to sustain MSC pluripotency regulating osteoblast commitment and growth, as well as for physiological remodeling of bone tissue.

Highlights on the Effects of Non-Coding RNAs in the Osteonecrosis of the Jaw

“…To current knowledge, few investigations have examined circRNAs as a potential ONJ biomarker. Standardizing the diagnosis of ONJ might be possible by a valuable biomarker, which could be also used to evaluate the risk in patients undergoing bisphosphonates treat-ment [52][53][54][55]. Numerous studies have hypothesized that circRNAs may sequester miRNAs to modify mRNA expression [56] and some of them, via their effects on ONJ-related miR-NAs, are essential in RANKL-induced RAW264.7 cells treated with bisphosphonates [57] (Figure 2).…”