MiRNA-20a-loaded graphene oxide–polyethylenimine enters bone marrow mesenchymal stem cells via clathrin-dependent endocytosis for efficient osteogenic differentiation

Abstract

Precise control of osteogenic differentiation of stem cells through osteogenesis-promoting microRNAs (miRNAs), such as miR-20a, is an exceptionally promising strategy to enhance bone regeneration. However, due to the difficulty of miRNAs in penetrating the negatively charged cell membrane and their susceptibility to degradation by Rnase in vivo, vectors are needed to protect miRNAs and effectively deliver them into cells. Graphene oxide (GO) has gained prominence as a vector for drug and gene delivery due to its outstanding physicochemical properties. In this study, the polyethyleneimine (PEI)-functionalized GO complex (GO–PEI) efficiently delivered miR-20a into rat bone marrow mesenchymal stem cells (BMSCs), resulting in a sustained high level of miR-20a in the cells. The GO–PEI/miR-20a complex could significantly promote osteogenic differentiation of BMSCs under the combined action of GO–PEI and miR-20a. In addition, the cellular uptake mechanism of the GO–PEI/miR-20a complex was investigated, confirming that it entered BMSCs via clathrin-mediated, energy-dependent endocytosis. In summary, the GO–PEI/miR-20a complex represents an effective platform for enhancing osteogenesis, and the elucidation of its cellular internalization mechanism contributes to a deeper understanding of the interactions between GO–PEI and cells.