Differentiation dependent expression of urocortin’s mRNA and peptide in human osteoprogenitor cells: influence of BMP-2, TGF-beta-1 and dexamethasone

Abstract

Urocortin-1 (UCN) a corticotropin releasing-factor (CRF) related peptide, has been found to be expressed in many different tissues like the central nervous system, the cardiovascular system, adipose tissue, and skeletal muscle. The effects of UCN are mediated via stimulation of CRF-receptors 1 and 2 (CRFR1 and 2, CRFR’s) with a high affinity for CRFR2. It has been shown that the CRF-related peptides and CRFR’s are involved in the regulation of stress-related endocrine, autonomic and behavioural responses. Using immunocytochemistry, immunohistochemistry and RT–PCR, we now can show the differentiation dependent expression of UCN mRNA and peptide in human mesenchymal progenitor cells (MSCs) directed to the osteoblastic phenotype for the first time. UCN expression was down regulated by TGF-beta and BMP-2 in the early proliferation phase of osteoblast development, whereas dexamethasone (dex) minimally induced UCN gene expression during matrix maturation after 24 h stimulation. Stimulation of MSCs for 28 days with ascorbate/beta-glycerophosphate (asc/bGp) induced UCN gene expression at day 14. This effect was prevented when using 1,25-vitamin D3 or dex in addition. There was no obvious correlation to osteocalcin (OCN) gene expression in these experiments. In MSCs from patients with metabolic bone disease (n = 9) UCN gene expression was significantly higher compared to MSCs from normal controls (n = 6). Human MSCs did not express any of the CRFR’s during differentiation to osteoblasts. Our results indicate that UCN is produced during the development of MSCs to osteoblasts and differentially regulated during culture as well as by differentiation factors. The expression is maximal between proliferation and matrix maturation phase. However, UCN does not seem to act on the osteoblast itself as shown by the missing CRFR’s. Our results suggest new perspectives on the role of urocortin in human skeletal tissue in health and disease.

Differentiation of Keratinocytes Modulates Skin HPA Analog

“…Interestingly, nuclear localization was not observed in case of CRF immunoreactivity, suggesting potentially different mechanism of signal transduction thought CRF receptors. Similarly, nuclear localization of UCN1 was observed previously in human retinal pigment epithelium and differentiating human osteoprogenitor cells (Tezval et al, 2009). Furthermore, treatment of immortalized HaCaT keratinocytes with UCN1, but not CRF resulted in rapid accumulation of Ca 2þ in the nucleus (Wiesner et al, 2003).…”

Urocortin is a novel regulator of osteoclast differentiation and function through inhibition of a canonical transient receptor potential 1-like cation channel

“…Unlike osteoclasts, we found that pre-osteoclasts expressed CRFR2b but not UCN itself. This is in contrast to a study by Tezval et al (2009), demonstrating the presence of UCN in human mesenchymal progenitor cells, but these cells had been directed toward an osteoblastic phenotype. Our findings suggest that UCN might represent an autocrine regulator of osteoclast function and a paracrine regulator of maturation and the concentration of UCN in the surrounding milieu could be controlled by osteoblastic CRF-BP release.…”

Dose dependent effect of C-type natriuretic peptide signaling in glycosaminoglycan synthesis during TGF-β1 induced chondrogenic differentiation of mesenchymal stem cells

“…3). These results were in agreement with previously published reports in terms of MSC characteristics of these trabecular bone-derived cells (Tezval et al 2009).…”

“…Subconfluent monolayers of cells were removed with 0.25% trypsin containing 1 mM EDTA (Biological Industries Ltd., Kibbutz Beit Haemek, Israel) and serially passaged at a ratio of 1:3. Obtained MSCs were characterized on the basis of immunohistochemistry, and flow cytometry analyses and according to their differentiation potentials as reported previously (Tezval et al 2009;all described below). To characterize the MSCs, monolayer cultures were fixed with methanol and air-dried.…”