Function Of RNA Binding Protein QKI In The Process Of Osteoblast Differentiation

Disabling and fatality rate increases year by year caused by bone metabolic diseases as a result of a high incidence of osteoporosis in postmenopausal women and the elderly,easy to cause osteoporosis fracture.At present,osteoblast and osteoclast was considered the most important regulating bone metabolic balance of two kinds of cells.Therefore,inhibition the bone resorption of osteoclasts,or enhancement bone formation function of osteoblasts is basic strategy for the treatment of osteoporosis.Previous research has shown that mesenchymal stem cells as seed cells of osteoblast,constantly added new osteoblast,maintain the balance of bone.However,MSC can also differentiate into fat cells under the specific condition.In the marrow cavity of patients with osteoporosis,a lot of fat cells can be seen,which indicates that the ability of MSC differentiation into osteoblast is weakened,and ability of differentiation into adipocyte is enhancement.Therefore,exploration the regulatory mechanism of MSC to the osteoblast is the key to the prevention and treatment of osteoporosis.Studies have found that RNA binding protein QKI can promote oligodendrocyte differentiation,and can regulate the differentiation process of muscle through the alternative splicing of target genes.Our previous studies found that C/EBP alpha targeted QKI participate in the regulation of macrophage differentiation and QKI can participate in the process of colon epithelial differentiation by inhibiting beta-catenin transcription activity and increased expression of p27.The above results suggested that QKI has a wide range of regulatory effects on differentiation of multiple cells,and is likely to plays an extremely important role in the process of MSC differentiation.Knockdown of QKI activated canonical Wnt/beta-catenin signaling pathway to accelerate the osteogenic differentiation of MSC,which play the protective role of osteoporosis.Objective(1)To evaluate the protective role of QKI in osteoporosis via knockdown of QKI expression in vivo.(2)To explore the effect of QKI on the fate decision of MSC differentiation by knockdown or overexpression of QKI to measure the levels of osteogenesis and adipogenesis in vivo and in vitro.(3)To discuss QKI molecular mechanism involved in regulation of MSC differentiation in vitro.Methods and Results(1)Micro-CT and fluorescent labeling were performed to detect bone mass,mineral apposition rate and bone formation rate in qki+/-mice.Results showed that apparent symptom relief of osteoporosis was seen in high-fat diet induced osteoporosis model.(2)HE staining and toluidine blue staining of bone sections,and lentivirus infection in C3H10T1/2 cell line to intervene QKI expression level were performed,then using western blot and qPCR to detect the expression level changes in the osteogenetic differentiation process,using ALP staining and alizarin red staining to detect osteogenesis and oil red O staining to detect adipogenesis.The results show that the expression of QKI increased and then decreased in the process of the osteogenetic differentiation.When QKI expression level was increased,adipocyte differentiation accelerated and reducing QKI expression level markedly enhance the capability of osteoblast differentiation,and osteogenic differentiation related genes,such as Runx2,Osterix,BSP,Collagen I and OCN expression level increased.(3)Cell immunofluorescence and western blot method were performed to explore the role of Wnt/beta-catenin signaling pathway in the regulatory effect of QKI on MSC differentiation.ConclusionRNA binding protein QKI plays an important role in the process of MSC differentiation into osteoblast or adipocyte.Knockdown of QKI expression level significantly promote the osteoblast differentiation in vivo and in vitro and has a protective effect on osteoporosis.Moreover,canonical Wnt/beta-catenin signaling pathway play an important role in this process.