BACKGROUND: The addition of growth factiors is commonly applied to improve the osteogenic differentiation of stem cells. However, for human pluripotent stem cells (hPSCs), their complex differentiation processes result in the unknown effect at different stages. In this study, we focused on the widely used bone forming peptide-1 (BFP-1) and investigated the effect and mechanisms of its addition on the osteogenic induction of hPSCs as a function of the supplementation period. METHODS: Monolayer-cultured hPSCs were cultured in osteogenic induction medium for 28 days, and the effect of BFP-1 peptide addition at varying weeks was examined. After differentiation for varying days (0, 7, 14, 21 and 28), the differentiation efficiency was determined by RT–PCR, flow cytometry, immunofluorescence, and alizarin red staining assays. Moreover, the expression of marker genes related to germ layers and epithelial-mesenchymal transition (EMT) was investigated at day 7. RESULTS: Peptide treatment during the first week promoted the generation of mesoderm cells and mesenchymal-like cells from hiPSCs. Then, the upregulated expression of osteogenesis marker genes/proteins was detected in both hESCs and hiPSCs during subsequent inductions with BFP-1 peptide treatment. Fortunately, further experimental design confirmed that treating the BFP-1 peptide during 7–21 days showed even better performance for hESCs but was ineffective for hiPSCs. CONCLUSION The differentiation efficiency of cells could be improved by determining the optimal treatment period.Our study has great value in maximizing the differentiation of hPSCs by adding osteogenesis peptides based on the revealed mechanisms and promoting the application of hPSCs in bone tissue regeneration.

Bone diseases, such as osteoporosis and osteoarthritis, have emerged as pressing public health concerns requiring immediate attention and resolution. Cellular therapy and tissue engineering techniques are among the most promising therapeutic approaches for such conditions. Human induced pluripotent stem cells (hiPSCs) possess remarkable capacity for indefinite self-renewal in vitro and the ability to differentiate into all somatic cell types originating from the three germ layers, thereby making them a promising source of osteoblasts. Consequently, it is crucial to establish a well-delineated system for osteogenic differentiation of hiPSCs in vitro, with the aim to generate osteoblast-like cells that conform to clinical application standards. Numerous research teams have achieved substantial advancements in both the direct osteogenic differentiation of hiPSCs and the indirect pathway via mesenchymal stem cells. In this article, we provide a comprehensive review of these two osteogenic differentiation pathways and their current applications, with the aim of serving as a valuable reference for bone regeneration technologies. Current research efforts have relied on embryoid body formation and monolayer induction methods utilizing biomaterials to develop a system that facilitates in vitro culture and osteogenic differentiation of hiPSCs. However, the existing research is primarily constrained by unclear system components and low efficiency. Therefore, the development of a stepwise and three-dimensional induction system based on stringent regulation by specific compounds is a primary research direction for the future.