Exosomes derived from bone marrow mesenchymal stem cells improve osteoporosis through promoting osteoblast...

Osteoporosis is the most common bone metabolic disease. Exosome exerts a crucial role in the development of multiple diseases. The aim of the study was to investigate the role of exosome derived from bone marrow mesenchymal stem cells (MSCs) in osteoporosis and its underlying mechanism.

MSCs were first isolated from rat bone marrow. After the surface antigen of MSCs was identified by flow cytometry, MSCs-derived exosomes (MSC-Exo) was extracted. The osteogenic and lipid differentiation abilities of BMSCs were determined by alizarin red staining and oil red staining, respectively. Quantitative reverse transcriptase-polymerase chain reaction (qRT-PCR) was used to detect the mRNA expressions of genes. Cell counting kit-8 (CCK-8) assay was used to detect the viability of hFOB 1.19 cells. Western blot was used to measure expressions of the specific surface markers in exosomes and the MAPK pathway-related proteins in hFOB 1.19 cells. Moreover, cell cycle of hFOB 1.19 was detected by flow cytometry.

We observed a positive identification of surface antigens in MSCs, which presented good multidirectional differentiation ability. The isolated MSC-Exo exhibited typical morphology and particle size of exosomes, and the detection of specific surface labeled protein was positive under an electron microscope. After co-culture of MSC-Exo and osteoblast cell line hFOB 1.19, we found that MSC-Exo could promote the proliferation of hFOB 1.19 cells. Moreover, mRNA and protein expressions of GLUT3 in cells were increased, and the cell cycle was also promoted. The expressions of related proteins in the MAPK signaling pathway were found to be promoted. Rescue experiments demonstrated that MSC-Exo could promote the growth and cell cycle of hFOB 1.19, which were reversed by p-JNK knockdown.

MSC-derived exosomes improve osteoporosis by promoting the proliferation of osteoblasts via MAPK pathway.