Background Recent reports demonstrated that somatic cells such as fibroblasts can be directly reprogrammed into other cell types including neurons and cardiomyocytes by introducing critical transcription factors involved in the differentiation of the corresponding cell lineages1,2. Such procedures in combination with co-transduction of a particular gene may allow creation of the cells with desired functions. If patient specific osteoblasts can be induced and engineered to produce IL-10, autologous transplantation of such cells may suppress inflammation and bone destruction in rheumatoid arthritis by modulating immune responses and osteoclast development.
Objectives To generate IL-10-producing mouse osteoblast-like cells from fibroblasts, and estimate potential effect of the cell supernatants on osteoclast differentiation.
Methods Various combinations of transcription factors were transduced into mouse embryonic fibroblasts (MEFs) with retroviral vectors and the efficiency of conversion into osteoblast-like cells were estimated by alizarine red S staining. IL-10 gene was also transduced to the cells that received the most effective combination of the transcription factors, and resultant cells were characterized by qRT-PCR, alkaline phosphatase staining, and alizarine red S staining. IL-10 production was measured by qRT-PCR and ELISA. The supernatant was added to a mouse macrophage cell line Raw264.7 cells that were induced to differentiate into osteoclasts by an addition of RANKL.
Results MEFs were successfully induced to massively produce bone matrix that were mineralized by calcium phosphate. Co-transduction of the IL-10 gene by means of a retrovirus vector resulted in establishment of osteoblasts that produced IL-10 at a significant level. The culture supernatant of the cells significantly suppressed osteoclast differentiation from Raw264.7 cells.
Conclusions IL-10-secreting osteoblasts were successfully generated from fibroblasts by direct reprogramming procedures. The cells may be useful in novel cell-based therapy against RA in the future.
Ieda, M. et al.: Cell, 142: 375-386, 2010.
Vierbuchen T.: Nature, 463: 1035-1041, 2010.
Disclosure of Interest None declared