Multiplexed Molecular Imaging Strategy Integrated with RNA Sequencing in the Assessment of the Therapeutic Effect of Wharton’s Jelly Mesenchymal Stem Cell-Derived Extracellular Vesicles for Osteoporosis

Abstract

Introduction:Osteoporosis is a result of an imbalance in bone remodeling. Mesenchymal stem cell-derived extracellular vesicles (MSC-EVs) have been considered as a potentially promising treatment for osteoporosis. However, the therapeutic effect, genetic alterations, and in vivo behavior of exogenous EVs for osteoporosis in mice models remain poorly understood. Methods: A multiplexed molecular imaging strategy was constructed by micro-positron emission tomography (µPET)/computed tomography (CT), µCT, and optical imaging modality which reflected the osteoblastic activity, microstructure, and in vivo behavior of EVs, respectively. RNA sequencing was used to analyze the cargo of EVs, and the bone tissues of ovariectomized (OVX) mice post EV treatment. Results: The result of [ 18 F]NaF µPET showed an increase in osteoblastic activity in the distal femur of EV-treated mice, and the bone structural parameters derived from µCT were also improved. In terms of in vivo behavior of exogenous EVs, fluorescent dye-labeled EVs could target the distal femur of mice, whereas the uptakes of bone tissues were not significantly different between OVX mice and healthy mice. RNA sequencing demonstrated upregulation of ECMrelated genes, which might associate with the PI3K/AKT signaling pathway, in line with the results of microRNA analysis showing that mir-21, mir-29, mir-221, and let-7a were enriched in Wharton's jelly-MSC-EVs and correlated to the BMP and PI3K/AKT signaling pathways. Conclusion:The therapeutic effect of exogenous WJ-MSC-EVs in the treatment of osteoporosis was successfully assessed by a multiplexed molecular imaging strategy. The RNA sequencing demonstrated the possible molecular targets in the regulation of bone remodeling. The results highlight the novelty of diagnostic and therapeutic strategies of EV-based treatment for osteoporosis.

Application and Molecular Mechanisms of Extracellular Vesicles Derived from Mesenchymal Stem Cells in Osteoporosis

“…Previous studies have found that the PI3K/Akt signaling pathway plays an important role in bone formation by regulating the potential and direction of early BMSC differentiation [ 107 ]. Lu et al [ 108 ] analyzed the changes in mRNA expression profiles in bone tissue of OVX mice treated with or without MSC-EVs by the next-generation sequencing (NGS) technique to identify the key intrinsic cargoes and the key signaling pathways involved in the treatment of OP with MSC-EVs. This study found that MSC-EVs may exert their therapeutic effects on OP by upregulating extracellular matrix-associated gene expression and activating the PI3K/Akt signaling pathway through the intrinsic miRNAs, including miR-21, miR-29, and miR-221.…”