Table 1.
Reported roles of exosomal ncRNAs in osteogenesis.
| Origin of exosomes | Experimental objective | Content analysis | Potential targets | In vitro effect | In vivo effect |
|---|---|---|---|---|---|
| MSCs | To identify the exosomal microRNA profiles in different osteogenic differentiation stages of MSCs | miR-31, miR-221, and miR-144 were decreased in exosomes from the late stage of osteogenic differentiation; miR-21 was upregulated. | miR-31: Osterix (Osx) and special AT-rich sequence-binding protein 2 (Satb2); miR-221: Runx2; miR-144; Smad4; miR-21: pry1, Sox2, Smad7 | Exosomes derived from hMSCs induce osteogenic differentiation of hMSCs in a stage-dependent manner | — |
| Myoblast | To study the cross-talk between muscle and bone | miR-27a-3p | Apc, a negative regulator of b-catenin; Atf3 | Myoblast exosomes affect the osteogenic differentiation of preosteoblasts | |
| Preosteoblasts | To elucidate the effect of exosomal miRNAs on preosteoblast differentiation | Let-7 miRNA | The high-mobility group AT-hook 2 (Hmga2) | Exosomes whose let-7 was inactivated efficiently lost their osteogenic differentiation capacity. | |
| Osteoblasts | To study the effect of the exosomes derived from mineralizing osteoblasts on the osteogenic differentiation of MSCs. | miR-667-3p, miR-6769b-5p, miR-7044-5p, miR-7668-3p, and miR-874-3p | Axin1, an important negative regulator of Wnt signaling pathway | Exosomes from MC3T3- E1 under 21 days of osteogenesis induction promote bone marrow stromal cell differentiation to osteoblasts | |
| BMSCs | To identify the miRNA profile in exosomes derived from aged mice | miR-183 cluster (miR-96/-182/-183) | Heme oxygenase-1 (Hmox1) | Aged exosomes inhibit the osteogenic differentiation of BMSCs | |
| BMSC | To study the underlying mechanism of MSCT ameliorating osteopenia in Fas-deficient-MRL/lpr mice | miR-29b | Dnmt1 | Improved osteogenic differentiation of MSCs from systemic lupus erythematosus (SLE) model | Infusing exosomes rescues osteoporotic phenotype |
| Adipose mesenchymal stem cells (ASCs) | To investigate whether exosomes derived from miR-375-overexpressing hASCs could enhance bone regeneration | miR-375 | Insulin-like growth factor-binding protein 3 (lgfbp3) | Improved the osteogenic differentiation of hBMSCs | Enhanced the bone regeneration in calvarial defect |
| Multiple myeloma (MM)--MSCs | To understand the myeloma-stroma interactions | RUNX-AS1 | Runx2 | Exosomes from MM-MSCs impaired the osteogenic differentiation of MSCs | Inhibitor of exosome secretion, prevented bone loss in MM |
| BMSC | To characterize the full small RNAome of MSC-produced exosomes | 5′ halves of tRNA | Runx2, Sox11, Smad3 |