Methyl-Beta-Cyclodextrin Restores Aberrant Bone Morphogenetic Protein 2-Signaling in Bone Marrow Stromal Cells Obtained from Aged C57BL/6 Mice

Abstract

As humans age, aberrancies in several signaling pathways occur. In the aging population, some patients display abnormal bone morphogenetic protein (BMP) signaling. This can lead to osteoporosis (OP), a debilitating bone disorder caused by an imbalance between osteoblasts and osteoclasts. In 2002, the Food and Drug Administration (FDA) approved usage of recombinant human BMP-2 (rhBMP-2) during spinal fusion surgery as it is crucial for bone formation. However, complications have been reported with rhBMP-2 and primary osteoblasts isolated from OP patients are unresponsive to BMP-2. While patient samples are available, previous medical history may alter results. Therefore, C57BL/6 mice, an aging model that displays aberrant BMP-signaling, can be utilized to investigate OP and aging. We show that BMP receptor type Ia (BMPRIa) is upregulated in the bone marrow stromal cells (BMSCs) of 15-month mice similar to previous data. We show that a conjugation between BMP-2 and Quantum Dots (QDot®s) effectively binds to BMPRIa and can investigate BMP-2 activity. After incubating BMSCs with methyl-β-cyclodextrin (MβCD), BMP-signaling is restored in 15-month mice as shown by western blotting and the von Kossa assay. MβCD may be used to rescue BMPRIa and the BMP-signaling pathway can be utilized by future therapeutics to treat OP.