Exosomes (Exos) are single‐membrane, secreted organelles (∼30 to ∼200 nm in diameter), which have the same topology as the parent cells and are enriched in cargo molecules. Exosomes derived from MSCs could affect the metabolism of bone tissue. Hu et al used exosomes derived from miR‐21 overexpressing adipose tissue‐derived MSCs (AD‐MSCs) to improve spine osteoporosis in ankylosing spondylitis (AS) mice. Cultured AD‐MSCs were transfected with lentivirus vectors containing miR‐21 or control vector, and the supernatant was centrifugated and filtrated to harvest the exosomes (miR‐21‐Exos or vector‐Exos). BALB/c mice were immunized with cartilage proteoglycan to establish proteoglycan‐ induced ankylosing spondylitis (PGIA) model. Six weeks later, PGIA mice were further injected with miR‐21‐Exos or vector‐Exos. Transfection of miR‐21 in AD‐ MSCs significantly enhanced miR‐21 levels in AD‐MSCs and their exosomes. miR‐21‐Exos showed concentration‐dependent protective effect against spine osteoporosis in PGIA mice, evidenced by increased bone mineral content and bone mineral density, reduced number of osteoclasts. Similarly, Zhang et al made miR-146a over-expressed in AD-MSCs and miR-146a exosomes (miR-146a-Exo) were isolated and characterized, to test the combination of AD-MSCs-Exo and miR-146a to exert the anti-inflammation effect in osteoclasts, providing a potential drug for the treatment of diabetic osteoporosis.

1.Hu L, Guan Z, Tang C, Li G, Wen J. Exosomes derived from microRNA-21 overexpressed adipose tissue-derived mesenchymal stem cells alleviate spine osteoporosis in ankylosing spondylitis mice. J Tissue Eng Regen Med. 2022 Jul;16(7):634-642.

2.Zhang L, Wang Q, Su H, Cheng J. Exosomes from Adipose Tissues Derived Mesenchymal Stem Cells Overexpressing MicroRNA-146a Alleviate Diabetic Osteoporosis in Rats. Cell Mol Bioeng. 2021 Aug 31;15(1):87-97.