A Single Nucleotide Polymorphism in Osteonectin 3′ Untranslated Region Regulates Bone Volume and Is Targeted by miR-433

Abstract

Osteonectin/SPARC is one of the most abundant non-collagenous extracellular matrix proteins in bone, regulating collagen fiber assembly and promoting osteoblast differentiation. Osteonectin-null and –haploinsufficient mice have low turnover osteopenia, indicating that osteonectin contributes to normal bone formation. In male idiopathic osteoporosis patients, osteonectin 3’ UTR single nucleotide polymorphism (SNP) haplotypes that differed only at SNP1599 (rs1054204) were previously associated with bone mass. Haplotype A (containing SNP1599G) was more frequent in severely affected patients, whereas haplotype B (containing SNP1599C) was more frequent in less affected patients and healthy controls. We hypothesized that SNP1599 contributes to variability in bone mass by modulating osteonectin levels. Osteonectin 3’UTR reporter constructs demonstrated that haplotype A has a repressive effect on gene expression compared to B. We found that SNP1599G contributed to a miR-433 binding site and miR-433 inhibitor relieved repression of the haplotype A, but not B, 3’ UTR reporter construct. We tested our hypothesis in vivo, using a knock-in approach to replace the mouse osteonectin 3’ UTR with human haplotype A or B 3’ UTR. Compared to haplotype A mice, bone osteonectin levels were higher in haplotype B mice. B mice displayed higher bone formation rate and gained more trabecular bone with age. When parathyroid hormone was administered intermittently, haplotype B mice gained more cortical bone area than A mice. Cultured marrow stromal cells from B mice deposited more mineralized matrix and had higher osteocalcin mRNA compared with A mice, demonstrating a cell-autonomous effect on differentiation. Altogether, SNP1599 differentially regulates osteonectin expression and contributes to variability in bone mass, by a mechanism that may involve differential targeting by miR-433. This work validates the findings of the previous candidate gene study, and it assigns a physiological function to a common osteonectin allele, providing support for its role in the complex trait of skeletal phenotype.

The Effects of <b><i>Hypericum perforatum</i></b> L. on the Proliferation, Osteogenic Differentiation, and Inflammatory Response of Mesenchymal Stem Cells from Different Niches

“…ON is synthesized by preosteoblasts and has less affinity to collagen. The ON transcript is quite stable, with a half-life of > 24 h under conditions of transcription arrest [Dole et al, 2015], and it can thus be concluded that the earlier synthesized ON, via the H. perforatum L.-treated DP-MSCs and BM-MSCs, accelerated osteogenic differentiation. The preosteoblasts matured on approximately day 14, and OCN was synthesized by these mature osteoblasts and marked the late phase of osteogenic differentiation.…”

“…Hypericum perforatum L., also known as St. John's wort [Oztürk et al, 2007], is known to have remarkable wound-healing and anti-inflammatory properties [Knüp-pel and Linde, 2004;Dole et al, 2015]. It is used to treat anxiety, depression, lacerations, burns, cancer, and bacterial and viral diseases, and is an antioxidant, analgesic, and neuroprotective agent [Rota et al, 2004].…”

Effect of Ocimum basilicum on mesenchymal stem cell proliferation and differentiation: Does the effect change according to niches?

“…ON is an early marker of osteogenesis that is synthesized by preosteoblasts and has less affinity to collagen. The ON transcript is quite stable, with a half-life of >24 hours under conditions of transcription arrest [23]. So we suggested that O. basilicum may accelarate the ostegenic differentiation in both DP-and BM-MSCs since the ON level was reduced signed to loose the stability being secreted early.…”

Thymbra Spicata Var. Intricata Induces Mesenchymal Stem Cell Proliferation and Osteogenic Differentiation

“…ON is an early marker of osteogenesis that is synthesized by preosteoblasts and has less affinity to collagen. The ON transcript is quite stable, with a half-life of >24 hours under conditions of transcription arrest 16 . The T. spicata var.…”