H19 activates Wnt signaling and promotes osteoblast differentiation by functioning as a competing endogenous RNA

Abstract

Bone homeostasis is tightly orchestrated and maintained by the balance between osteoblasts and osteoclasts. Recent studies have greatly expanded our understanding of the molecular mechanisms of cellular differentiation. However, the functional roles of non-coding RNAs particularly lncRNAs in remodeling bone architecture remain elusive. In our study, lncRNA H19 was found to be upregulated during osteogenesis in hMSCs. Stable expression of H19 significantly accelerated in vivo and in vitro osteoblast differentiation. Meanwhile, by using bioinformatic investigations and RIP assays combined with luciferase reporter assays, we demonstrated that H19 functioned as an miRNA sponge for miR-141 and miR-22, both of which were negative regulators of osteogenesis and Wnt/β-catenin pathway. Further investigations revealed that H19 antagonized the functions of these two miRNAs and led to de-repression of their shared target gene β-catenin, which eventually activated Wnt/β-catenin pathway and hence potentiated osteogenesis. In addition, we also identified a novel regulatory feedback loop between H19 and its encoded miR-675-5p. And miR-675-5p was found to directly target H19 and counteracted osteoblast differentiation. To sum up, these observations indicate that the lncRNA H19 modulates Wnt/β-catenin pathway by acting as a competing endogenous RNA, which may shed light on the functional role of lncRNAs in coordinating osteogenesis.

Identification and Characterization of Long Non-Coding RNAs in Osteogenic Differentiation of Human Adipose-Derived Stem Cells

“…The authors argued that this might be due to the negative-feedback loop associated with H19 and miR-675-5p. Meanwhile, they revealed another mechanism for H19 in the enhancement of osteogenic differentiation of BMSCs that concerned H19 -mediated activation of Wnt signaling by acting as a microRNA sponge for miR-141 and miR-22, both of which negatively regulated β-catenin [20]. Here, we found that H19 expression decreased significantly during osteogenic differentiation of human ASCs.…”

“…The expression of H19 , which is upregulated and exhibits functions involved in osteogenic differentiation of human BMSCs [16, 18, 20], was decreased (Fold change: 3.81) in osteogenic differentiated ASCs as compared with undifferentiated cells according to our microarray results. To validate the differences in these results and explore the possible function of H19 in ASCs, we measured dynamic H19 expression during osteogenic processes of human ASCs and examined the effect of H19 knockdown on osteogenesis of human ASCs.…”

“…Several studies reported that H19 was upregulated during osteogenesis in BMSCs [16, 18, 20]. In addition, H19 promotes osteogenic differentiation of BMSCs via the transforming growth factor β-1/Smad3/histone deacetylase pathway, with microRNA (miR) -675 derived from H19 partially responsible for this pro-osteogenic effect [16].…”

Single-nucleus RNA-seq of differentiating human myoblasts reveals the extent of fate heterogeneity

“…The significance of this upregulation is currently unclear. Since H19 was shown to play an important role in adult stem cell maintenance (71,72) and also activates Wnt signaling by upregulation of β -catenin (73), it is possible that this H19 upregulation may be associated with the observed MSC-like phenotype of MNCs. Intriguingly, there is a subset of miRNAs that are perfectly anti-correlated to the expression of their primary lncRNA.…”

Long noncoding RNAs in lipid metabolism

“…A similar function in stabilizing SREBP-1c and promoting lipogenesis has been described for lncRNA H19, which like MALAT1, is upregulated by fatty acids [26 ■ ]. H19 was originally reported to function as a protein scaffold in tumor development and osteoblast differentiation [27,28]. Further study showed that in hepatocytes H19 alters SREBP-1c activity at both the mRNA and protein levels.…”