Saint Francis University

About: Saint Francis University is a education organization based out in Loretto, Pennsylvania, United States. It is known for research contribution in the topics: Population & Osteoblast. The organization has 1694 authors who have published 2038 publications receiving 87149 citations.

Insulin-like growth factor II promoter expression in cultured rodent osteoblasts and adult rat bone.

Abstract: Insulin-like growth factor (IGF)-II stimulates bone formation by increasing the replication of cells of the osteoblastic lineage and by enhancing the differentiated function of the osteoblast. Although IGF-II is synthesized by skeletal cells, little is known about the mechanisms involved and its regulation by growth factors. IGF-II expression is tissue specific and is developmentally regulated. In the present study, we examined the expression of IGF-II in fetal rat, newborn mouse and MC3T3-E1 osteoblastic (Ob) cells, and in adult rat calvariae. We also determined mechanisms involved in the regulation of IGF-II by platelet-derived growth factor (PDGF) BB, fibroblast growth factor-2 (FGF-2), and transforming growth factor (TGF) β1. Northern analysis revealed IGF-II transcripts of 3.6 and 1.2 kb in osteoblastic cells and adult rat calvariae. Ribonuclease (RNase) protection assay using probes specific to the three known IGF-II promoters, P1, P2, and P3, demonstrated messenger RNA (mRNA) expression driven by P...

Nephroblastoma overexpressed (Nov) is a novel bone morphogenetic protein antagonist.

Abstract: Nephroblastoma overexpressed (Nov), a member of the CCN family of proteins, is expressed by osteoblasts and its transcription is regulated by transforming growth factor (TGF)-beta and bone morphogenetic proteins (BMP). CCN proteins can interact with TGF-beta, BMPs, and Wnt. We explored the function of Nov in skeletal cells, in vitro and in vivo. Constitutive overexpression of Nov in cells of the osteoblastic lineage impaired osteoblastic differentiation, opposed the biological effects of BMP-2 and Wnt 3 and impaired BMP-2 and Wnt signaling, indicating that Nov has BMP-2 antagonistic activity. Transgenic mice overexpressing Nov under the control of the osteocalcin promoter exhibited osteopenia secondary to decreased bone formation, confirming the effects in vitro. GST pulldown experiments demonstrated direct Nov-BMP interactions. In conclusion, Nov has BMP antagonistic properties and inhibits osteoblastogenesis and osteoblastic function.

Insulin-like growth factors sustain insulin-like growth factor-binding protein-5 expression in osteoblasts.

Abstract: Insulin-like growth factors (IGFs) I and II are considered to be autocrine regulators of bone cell function. Recently, we demonstrated that IGF-I induces IGF-binding protein-5 (IGFBP-5) expression in cultures of osteoblast-enriched cells from 22-day fetal rat calvariae (Ob cells). In the present study, we postulated that IGFs play an autocrine role in the maintenance of IGFBP-5 basal expression in Ob cells. IGFBP-2 and -3, at concentrations that bind endogenous IGFs, decreased IGFBP-5 mRNA levels, as determined by Northern blot analysis, and protein levels, as determined by Western immunoblots of extracellular matrix extracts of Ob cells. IGFBP-2 and -3 in excess inhibited IGFBP-5 heterogeneous nuclear RNA levels, as determined by RT-PCR, and did not alter the half-life of IGFBP-5 mRNA in transcriptionally arrested Ob cells. In conclusion, blocking endogenous IGFs in Ob cells represses IGFBP-5 expression, suggesting that IGFs are autocrine inducers of IGFBP-5 synthesis in osteoblasts.

Hospital Pharmacy Pulse - Recent Publications on Medications and Pharmacy

Abstract: Hospital Pharmacy presents this feature to keep pharmacists abreast of new publications in the medical/pharmacy literature. Articles of interest will be abstracted monthly regarding a broad scope o...