MicroRNA-188 regulates age-related switch between osteoblast and adipocyte differentiation
Chang-Jun Li, Peng Cheng, Meng-Ke Liang, Yu-Si Chen, Qiong Lu, Jin-Yu Wang, Zhu-Ying Xia, Hou-De Zhou, Xu Cao, Hui Xie, Er-Yuan Liao, Xiang-Hang Luo
Chang-Jun Li, Peng Cheng, Meng-Ke Liang, Yu-Si Chen, Qiong Lu, Jin-Yu Wang, Zhu-Ying Xia, Hou-De Zhou, Xu Cao, Hui Xie, Er-Yuan Liao, Xiang-Hang Luo
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Research Article Bone biology

MicroRNA-188 regulates age-related switch between osteoblast and adipocyte differentiation

Abstract

Bone marrow mesenchymal stem cells (BMSCs) exhibit an age-dependent reduction in osteogenesis that is accompanied by an increased propensity toward adipocyte differentiation. This switch increases adipocyte numbers and decreases the number of osteoblasts, contributing to age-related bone loss. Here, we found that the level of microRNA-188 (miR-188) is markedly higher in BMSCs from aged compared with young mice and humans. Compared with control mice, animals lacking miR-188 showed a substantial reduction of age-associated bone loss and fat accumulation in bone marrow. Conversely, mice with transgenic overexpression of miR-188 in osterix+ osteoprogenitors had greater age-associated bone loss and fat accumulation in bone marrow relative to WT mice. Moreover, using an aptamer delivery system, we found that BMSC-specific overexpression of miR-188 in mice reduced bone formation and increased bone marrow fat accumulation. We identified histone deacetylase 9 (HDAC9) and RPTOR-independent companion of MTOR complex 2 (RICTOR) as the direct targets of miR-188. Notably, BMSC-specific inhibition of miR-188 by intra–bone marrow injection of aptamer-antagomiR-188 increased bone formation and decreased bone marrow fat accumulation in aged mice. Together, our results indicate that miR-188 is a key regulator of the age-related switch between osteogenesis and adipogenesis of BMSCs and may represent a potential therapeutic target for age-related bone loss.

Authors

Chang-Jun Li, Peng Cheng, Meng-Ke Liang, Yu-Si Chen, Qiong Lu, Jin-Yu Wang, Zhu-Ying Xia, Hou-De Zhou, Xu Cao, Hui Xie, Er-Yuan Liao, Xiang-Hang Luo

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Figure 3

Mir188–/– mice show higher osteoblastic bone formation and lower marrow fat accumulation in aged mice.

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Mir188–/– mice show higher osteoblastic bone formation and lower marrow...
(A) Representative images of calcein double labeling of trabecular (Tb), endosteal (Eb), and periosteal bone (Pb) with quantification (B–D) of bone formation rate per bone surface (BFR/BS) in femora of 18-month-old WT and Mir188–/– mice. Scale bar: 50 μm. n = 6 per group. (E) Representative images of toluidine blue staining with quantification of number and area of adipocytes in distal femora (F and G). Scale bar: 100 μm. (H) Representative images of osteocalcin immunohistochemical staining with quantification of number of osteoblasts in distal femora (I). Scale bar: 100 μm. n = 6 per group. (J) Representative images of Oil Red O staining of lipids (top) and Alizarin Red S staining of matrix mineralization (bottom) in BMSCs from Mir188–/– mice and WT mice cultured in adipogenesis induction medium for 14 days and osteogenesis induction medium for 21 days, respectively. Scale bar: 100 μm. Data are representative of 3 independent experiments. Data shown as mean ± SD. *P < 0.05, **P < 0.01 (Student’s t test).