Project description:The level of 12,488 transcripts in osteoblastic OB-6 cells was quantified with Affymetrix U74A chips under basal conditions (0 time), and after addition of 50 nM PTH for 30 or 60 minutes
Project description:The level of 12,488 transcripts in osteoblastic OB-6 cells was quantified with Affymetrix U74A chips under basal conditions (0 time), and after addition of 50 nM PTH for 30 or 60 minutes Keywords: time-course
Project description:Osteoclastic bone resorption and osteoblastic bone formation/replenishment are closely coupled in bone metabolism. Anabolic parathyroid hormone (PTH), which is commonly used for treating osteoporosis, shifts the balance from osteoclastic to osteoblastic, although the mechanisms underlying this phenomenon are unclear. Here we identified a serine protease inhibitor, secretory leukocyte protease inhibitor (SLPI), as a novel coupling factor that is involved in the PTH-mediated shift to the osteoblastic phase. SLPI was highly upregulated in osteoblasts by PTH, and genetic ablation of SLPI severely impaired PTH-induced bone formation. SLPI induction in osteoblasts enhanced osteoblast differentiation intracellularly and was also secreted extracellularly, attracting neighboring osteoclasts to suppress osteoclastic function. Intravital bone imaging revealed that the PTH-mediated association between osteoblasts and osteoclasts was disrupted in the absence of SLPI. Collectively, these results demonstrate that SLPI, a previously unrecognized bone-coupling factor, mediates the communication of osteoblasts with osteoclasts to promote PTH-induced bone formation.
Project description:With the aim of identifying new pathways and genes regulated by PTH(1-34) and PTH-related protein 1-141 [PTHrP(1-141)] in osteoblasts, this study was carried out using a mouse marrow stromal cell line, Kusa 4b10, that acquires features of the osteoblastic phenotype in long-term culture conditions. After the appearance of functional PTH receptor 1 (PTHR1) in Kusa 4b10 cells, they were treated with either PTH(1-34) or PTHrP(1-141), and RNA was subjected to Affymetrix whole mouse genome array.
