The directly converted osteoblasts (dOBs) showed similar gene expression profiles as normal osteoblasts and contributed to bone repair after transplantation into mice with bone defects. 3B). 5-8 They identified colonies consisting of fibroblasts by plating bone marrow cells in cultures containing only medium and fetal bovine serum. Genome-wide gene expression profiles also indicated that RXOL-transduced cells were most similar to osteoblasts among all the cells tested (including MSC-OBs), and vice versa (Fig. In the present study, we attempted to directly convert human fibroblasts into osteoblasts by genetically introducing osteoblast-specific transcription factors and reprogramming factors. GFP-labeled dOBs were transplanted into the bone defect lesions, and human osteocalcin was visualized by immunohistochemical staining. OL-transduced cells expressed Runx2 at a low level and did not significantly express mRNA for the Osterix gene (Fig. (38) recently reported that Oct4 and Sox2 present mesendodermal and ectodermal differentiation cues, respectively, and that the balance between these counteracting cues may facilitate reprogramming. Osteoblasts induced from a patient’s own somatic cells or allogenic cells also may be applicable to cell-based therapy against bone resorptive conditions associated with osteoporosis, bone disruption caused by rheumatoid arthritis, and alveolar bone resorption due to periodontitis. Cardiac fibroblasts are critical in extracellular matrix homeostasis. Bone can suffer from various conditions such as fractures and diseases such as osteoporosis, osteogenesis imperfecta and tumors. It has been demonstrated that transplantation of skin fibroblasts that overexpress bone morphogenetic protein-2 (BMP-2) via adenoviral vectors can successfully repair mouse calvarial bone defects [1]. Copyright © 2021 National Academy of Sciences. Fibroblasts produce collagen fibers that connect the broken bone ends, while osteoblasts start to form spongy bone. Astronomers thought they’d finally figured out where gold and other heavy elements in the universe came from. In addition, c-Myc is considered a crucial factor in the direct reprogramming of mouse fibroblasts into neural stem cells (18, 20) and chondrocytes (21). (D) Transplantation was performed as above, but with dOBs infected with a GFP retrovirus vector before transplantation. 1, Oct4 alone moderately induced the osteoblast-like phenotypes. 2021 Jan;26(1):103-117. doi: 10.1038/s41380-020-00930-0. Depending on the type, severity of the fracture and distance between bone fragments, bones may heal directly by building new bone onto the fracture site (direct bone healing or contact healing) or may heal in a process like endochondral bone formation (indirect bone healing). Front Bioeng Biotechnol. FGF6 is involved in muscle regeneration and those events that occur during the healing process. Thus, the present study suggests that the transplantation of skin fibroblasts transduced with BMP-2 gene is more effective than that of cells transduced with Runx2 as a source of cell-mediated gene therapy for bone defects. 1, 2, and 3). 2018 Aug 21;9(3):50. doi: 10.3390/jfb9030050. doi: 10.1097/BOT.0b013e3181cde5d1. Physiologically this could function as feedback mechanism during bone growth and fracture repair but could also be overly expressed in bone disease, such as hypophosphatemic rickets . Ossification begins as mesenchymal cells form a template of the future bone. Hawkins D, Abrahamse H. Influence of broad-spectrum and infrared light in combination with laser irradiation on the proliferation of wounded skin fibroblasts. Furthermore, dOBs did not require continuous expression of the exogenous genes to maintain their phenotype. This article contains supporting information online at www.pnas.org/lookup/suppl/doi:10.1073/pnas.1420713112/-/DCSupplemental. Bone repair was estimated by macroscopic, radiographic, biomechanical, and histological examinations at 21 d after transplantation. Recent studies indicate that L-Myc may substitute for c-Myc (29). Dermal fibroblasts are a good candidate for tendon tissue engineering because they are similar to the tenocytes used for collagen synthesis. Amanda Rodewald, Ivan Rudik, and Catherine Kling talk about the hazards of ozone pollution to birds. To examine whether dOBs can enhance bone regeneration, we transplanted dOBs and fibroblasts into bone defect lesions surgically created at the femurs of NOD/SCID mice. NLM Thus, direct reprogramming may provide another option for such patients in whom MSC transplantation might not be an appropriate therapy. 6C). These results demonstrate that fibroblasts were directly converted into dOBs without passing through an immature pluripotent stage. In light of recent results, they’re not so sure. Fibroblasts are large flat spindle-shaped cells with processes that extend out from the ends of the cell body. S1B). (A) After culturing for 14 d, mRNA levels for ALP and osteocalcin genes were quantified by real-time RT-PCR. Parathyroid hormone: is there a role in fracture healing? (Original magnification: 100× in A and B.) Yadav et al used buffalo fetal fibroblasts to have successfully differentiated them into adipogenic and osteogenic cells [14]. The detailed molecular mechanisms involved in this cell conversion remain to be elucidated, however. Triangles indicate bone defect lesions; arrowheads, regenerated bone tissue. Enter multiple addresses on separate lines or separate them with commas was added to the set... Honjo for technical support a tissue S ( Upper ) or H & E ( ). 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