Exosomal miRNA-128-3p from mesenchymal stem cells of aged rats regulates osteogenesis and bone fracture healing by targeting Smad5

Abstract

Transplantation of mesenchymal stem cells (MSCs) has been considered an effective therapeutic treatment for a variety of diseases including bone fracture. However, there are associated complications along with MSCs transplantation. There is evidence to show that exosomes (Exos) derived from MSCs exert a similar paracrine function. In addition, repair capabilities of MSCs decline with age. Hence, this study aims to confirm whether the Exos protective function on osteogenic differentiation and fracture healing from aged MSCs was attenuated. This information was used in order to investigate the underlying mechanism. MSCs were successfully isolated and identified from young and aged rats, and Exos were then obtained. Aged-Exos exhibited significantly attenuated effects on MSCs osteogenic differentiation in vitro and facture healing in vivo. Using miRNA array analysis, it was shown that miR-128-3p was markedly upregulated in Aged-Exos. In vitro experiments confirmed that Smad5 is a direct downstream target of miR-128-3p, and was inhibited by overexpressed miR-128-3p. A series gain-and loss-function experiment indicated that miR-128-3P serves a suppressor role in the process of fracture healing. Furthermore, effects caused by miR-128-3P mimic/ inhibitor were reversed by the application of Smad5/siSmad5. Taken together, these results suggest that the therapeutic effects of MSCs-derived Exos may vary according to differential expression of miRNAs. Exosomal miR-128-3P antagomir may act as a promising therapeutic strategy for bone fracture healing, especially for the elderly.

Mesenchymal stem cell exosomes in bone regenerative strategies—a systematic review of preclinical studies

“…No treatment NA NA NA NA 6 weeks 7. Normal group NA NA NA NA 6 weeks Xu [ 57 ] 2020 1. Exosomes from 4-week old rat BM-MSCs 1 ​μg/μL 200 ​μL Injection near fracture site At day 0 2, 3, 4 weeks 2.…”

“…Increasingly, MSC exosomes have replicated the wide-ranging therapeutic efficacies of MSCs in several injury and disease indications such as myocardial ischemia reperfusion injury [ 29 ], drug-induced liver injury [ 30 ], retinal laser injury [ 31 ], pulmonary hypertension [ 32 ], and graft-versus-host-disease [ 33 , 34 ]. MSC exosomes were also reported to be efficacious in enhancing skeletal muscle regeneration [ 35 , 36 ] ​and more recently cartilage [ 23 , [37] , [38] , [39] , [40] ] and bone regeneration [ [41] , [42] , [43] , [44] , [45] , [46] , [47] , [48] , [49] , [50] , [51] , [52] , [53] , [54] , [55] , [56] , [57] , [58] , [59] , [60] , [61] , [62] , [63] ].…”

Exosome: A Novel Nanocarrier Delivering Noncoding RNA for Bone Tissue Engineering

“…The latest two years of exosome miRNA in the regulation of bone growth and development is listed in Table 1. Exosome miR-128-3p regulates osteogenesis and fracture healing by targeting Smad5 [48]. Decreasing miR-221-3p in exosomes can significantly reduce chondrocyte proliferation and migration in vitro [49].…”

Chitosan-miRNA functionalized microporous titanium oxide surfaces via a layer-by-layer approach with a sustained release profile for enhanced osteogenic activity

“…It is believed that miRNAs mimic the natural differentiation pathway and delicately control multiple genes, constituting a much healthier stimulator of stem cell differentiation [17]. Recently, reports on the regulatory effect of miRNAs on osteogenesis have continued to expand [18][19][20][21], among which miR-138 is reported to be a negative regulator of the osteogenic differentiation of mesenchymal stem cells (MSCs). AntimiR-138 inhibition of endogenous miR-138 levels was reported to enhance bone formation in vivo [18].…”