TY - JOUR
T1 - Two novel probes reveal tubular and vascular Arg-Gly-Asp (RGD) binding sites in the ischemic rat kidney
AU - Romanov, Victor
AU - Noiri, Eisei
AU - Czerwinski, Grzegorz
AU - Finsinger, Dirk
AU - Kessler, Horst
AU - Goligorsky, Michael S.
N1 - Funding Information:
These studies were supported by NIH grant DK41573 (MSG) and by the NC DHHS contract NO1-CO-46000 with ABL. We are grateful to Dr. Jan Lukszo of NIAIDILMS for the laser dcsorption mass spectra; to preparing vascular trees, to Dr. Frederick Miller (Dept. of Pathology, SUNY Stony Brook) for guidance in immunohistochemical studies, and to Mr. David Colfiesh for help with confocal microscopy. Results of studies with 99TC-R6D have been published in JAm Soc Nephrol 7:2682—2688, 1996.
PY - 1997
Y1 - 1997
N2 - We have previously demonstrated that RGD peptides prevent tubular obstruction in ischemic acute renal failure (ARF) and suggested that exposed unoccupied integrin receptors represent the target for such therapy. The present study investigated the topography of RGD binding sites and integrin receptors in ischemic rat kidneys. Two RGD peptides were synthesized: a cyclic biotinylated (Bt) RGD peptide and a linear RGD peptide (GRGDSP) labeled with rhodamine green (RhoG). Rats were subjected to 45 minutes of renal artery occlusion, kidneys were harvested at different times post- ischemia, and stained with RGD peptides and a panel of antibodies to integrins. In control Bt-RGD staining was undetectable in alkaline phosphatase histochemistry, whereas immunofluorescence detection with Rho- streptavidin conjugate as well as RhoG-GRGDSP staining faintly decorated the basolateral aspect of the proximal tubular cells in a punctate fashion. In contrast, ischemic kidneys showed binding to the basolateral and apical aspects of proximal tubules, peritubular capillaries, and desquamated cells within tubular lumen. The most conspicuous staining of ischemic kidneys was obtained with antibodies to the β1 (labeling of the apical aspect of proximal and distal tubules, as well as desquamated cells obstructing tubular lumen) and the αV (glomeruli, tubular epithelia, intima of blood vessels stained faintly, while the obstructing cellular conglomerates showed intense staining) subunits. Double staining with Bt-RGD and antibodies against the β1 and αVβ3 integrins showed co-localization of staining within the tubules and vasculature, respectively. In vitro attachment of HL-60 leukocytes to the endothelial cells was inhibited by the cyclic RGD peptide. In conclusion, expression of RGD binding sites and β1 integrin subunits along the apical aspect of tubular epithelia and on the surface of desquamated cells is in concert with the hypothesis on the pathogenetic role of RGD-recognizing integrins in tubular obstruction. The expression of RGD binding sites along the intimal surface of blood vessels in ischemic kidneys suggests an additional target for RGD peptides in vascular endothelial cells.
AB - We have previously demonstrated that RGD peptides prevent tubular obstruction in ischemic acute renal failure (ARF) and suggested that exposed unoccupied integrin receptors represent the target for such therapy. The present study investigated the topography of RGD binding sites and integrin receptors in ischemic rat kidneys. Two RGD peptides were synthesized: a cyclic biotinylated (Bt) RGD peptide and a linear RGD peptide (GRGDSP) labeled with rhodamine green (RhoG). Rats were subjected to 45 minutes of renal artery occlusion, kidneys were harvested at different times post- ischemia, and stained with RGD peptides and a panel of antibodies to integrins. In control Bt-RGD staining was undetectable in alkaline phosphatase histochemistry, whereas immunofluorescence detection with Rho- streptavidin conjugate as well as RhoG-GRGDSP staining faintly decorated the basolateral aspect of the proximal tubular cells in a punctate fashion. In contrast, ischemic kidneys showed binding to the basolateral and apical aspects of proximal tubules, peritubular capillaries, and desquamated cells within tubular lumen. The most conspicuous staining of ischemic kidneys was obtained with antibodies to the β1 (labeling of the apical aspect of proximal and distal tubules, as well as desquamated cells obstructing tubular lumen) and the αV (glomeruli, tubular epithelia, intima of blood vessels stained faintly, while the obstructing cellular conglomerates showed intense staining) subunits. Double staining with Bt-RGD and antibodies against the β1 and αVβ3 integrins showed co-localization of staining within the tubules and vasculature, respectively. In vitro attachment of HL-60 leukocytes to the endothelial cells was inhibited by the cyclic RGD peptide. In conclusion, expression of RGD binding sites and β1 integrin subunits along the apical aspect of tubular epithelia and on the surface of desquamated cells is in concert with the hypothesis on the pathogenetic role of RGD-recognizing integrins in tubular obstruction. The expression of RGD binding sites along the intimal surface of blood vessels in ischemic kidneys suggests an additional target for RGD peptides in vascular endothelial cells.
KW - Binding sites
KW - Integrins
KW - Ischemic kidney
KW - Obstruction
KW - Probes
KW - RGD peptides
UR - http://www.scopus.com/inward/record.url?scp=0030765404&partnerID=8YFLogxK
U2 - 10.1038/ki.1997.308
DO - 10.1038/ki.1997.308
M3 - Article
C2 - 9211351
AN - SCOPUS:0030765404
SN - 0085-2538
VL - 52
SP - 93
EP - 102
JO - Kidney International
JF - Kidney International
IS - 1
ER -