Naslov
Urine release of systemically administered bone morphogenetic protein hybrid molecule

Autori
Grgurević, Lovorka ; Maček, Boris ; Erjavec, Igor ; Oppermann, Hermann ; Mann, Matthias ; Vukičević, Slobodan

Izvornik
Journal of Nephrology (1121-8428) 20 (2007), 3; 311-319

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, članak, znanstveni

Ključne riječi
bone morphogenetic protein-6; mass spectrometry; urine release of bmps; osteogenic protein; kidney-bone; tgf-beta; expression; Op-1; severity; domains; disease; complex; family

Sažetak
Although it is well known that TGF-beta circulates, the presence and activity of endogenous bone morphogenetic proteins (BMPs) in biological fluids has not been studied. Here we investigated the urine secretion of a systemically administered BMP hybrid molecule. A dimeric recombinant human BMP molecule consisting of the BMP-7 prodomain and the BMP-6 mature domain was constructed and injected into Sprague Dawley rats. The blood was collected from the rats' orbital plexus, and 24-hour urine samples were pooled and purified using a heparin sepharose column. Protein identity was confirmed by Western blot and by liquid chromatography-mass spectrometry (LC-MS) of the resulting peptides. Urine-derived protein from the 35-kDa band was bound to inactive demineralized bone matrix and implanted subcutaneously into rats. Western blot analysis of sera demonstrated that BMP-7/6 remained intact in the rat plasma and could still be visualized 30 minutes after its systemic administration. Two protein bands at 35 and 39 kDa were detected with anti-BMP antibodies in the urine of rats, corresponding to the mature active BMP-6 dimer and the prodomain of BMP-7, respectively. LC-MS analysis detected only peptides derived from the BMP-7/6 molecule. Histological analysis of implanted pellets revealed formation of a new endochondral bone 14 days following implantation. These results show for the first time that systemically administered BMP-7/6 hybrid molecule is secreted into the urine and that its biological activity is preserved, suggesting that analysis of BMP in urine might reflect its presence in serum.

Izvorni jezik
Engleski

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