The functional analysis of RANKL signaling in osteoclast for developing the agonist of SHP-1

点击翻译按钮获取中文摘要

The SHP-1 is the phosphatase and the reduction of its phosphatase activity leads to the significant increase of bone resorption activity of osteoclasts, suggesting that SHP-1 works as a negative regulator of osteoclast activity. Here we have planned to develop the inhibitor of osteoclast activity by designing the agonist, which would increase the interaction between SHP-1 and its binding protein. We had already found SHP-1 binding proteins by using the MALDI-TOF system in SHP-1-transfected 293Tcells. The binding proteins were La binding protein, ribosome protein L4, protein tyrosine phosphatase 1c, KRT19. These proteins were, however, the fragments of SHP-1 or non-specific binding proteins, thereby we could not get in the next step such as screening for the functional proteins by using siRNA and develop the agonist of SHP-1. To solve this problem, we have also tried to find the SHP-1 binding protein by using the GST pull-down assay in murine macrophage cell line, RAW 264.7, but we could not identify the proteins. In spite of these results, it should be mentioned that the new system for measuring osteoclast activity has been established by using the device for measuring the 3-dimensional surface morphology which was purchased from this grant for screening the functional proteins which affects osteoclast activity. Previously the assessment of osteoclast activity was obtained by measuring 2-dimentinal area of the resorption pits, and the evaluation of the osteoclast activity has not been certain. In the near future, this evaluation system would be a powerful tool for the drug development.