Heat shock protein-70 repairs proximal tubule structure after renal ischemia

• Published in: Kidney international Vol. 58; no. 6; pp. 2400 - 2407
• Main Authors: Bidmon, Bettina, Endemann, Michaela, Müller, Thomas, Arbeiter, Klaus, Herkner, Kurt, Aufricht, Christoph
• Format: Journal Article
• Language: English
• Published: New York, NY Elsevier Inc 01-12-2000; Nature Publishing; Elsevier Limited
• Subjects: Animals; Antibodies - pharmacology; apical membrane domain; Biological and medical sciences; Blotting, Western; Cell Fractionation - methods; cellular repair; cytoskeleton; Cytoskeleton - metabolism; detergent extraction; Detergents; Dose-Response Relationship, Drug; HSP70 Heat-Shock Proteins - immunology; HSP70 Heat-Shock Proteins - pharmacology; injury; Ischemia - drug therapy; Ischemia - pathology; Kidney Cortex - blood supply; Kidney Cortex - enzymology; Kidney Cortex - pathology; Kidney Tubules, Proximal - blood supply; Kidney Tubules, Proximal - enzymology; Kidney Tubules, Proximal - pathology; Kidneys; Male; Medical sciences; Na,K-ATPase; Nephrology. Urinary tract diseases; Octoxynol; Rats; Rats, Sprague-Dawley; renal cortex; Sodium-Potassium-Exchanging ATPase - analysis; Sodium-Potassium-Exchanging ATPase - metabolism; Urinary system involvement in other diseases. Miscellaneous; apical membrane domain; renal cortex; cytoskeleton; Na,K-ATPase; detergent extraction; injury; cellular repair; Kidney disease; Translocation; Animal model; Urinary system disease; Rat; Rodentia; Cardiovascular disease; In vitro; Kidney; Vertebrata; Renal tubule; Mammalia; Ischemia; Animal; Heat shock protein; Cytoskeleton
• ISSN: 0085-2538; 1523-1755
• DOI: 10.1046/j.1523-1755.2000.00423.x

Heat shock protein-70 repairs proximal tubule structure after renal ischemia.
Recent studies have suggested a role of heat shock protein (HSP)-70 in cytoskeletal repair during cellular recovery from renal ischemia. The aim of this study was to test the hypothesis that HSP-70 interacts in vitro with cytoskeletal elements obtained from rat renal cortex during early reflow after renal ischemia.
Cellular proteins were fractionated into cytoskeletal pellets and noncytoskeletal supernatants by Triton X-100 extraction of rat renal cortex obtained after 15 minutes or 18 hours of reflow after 45 minutes of renal ischemia, or from controls. Aliquots of isolated pellets were coincubated with aliquots of isolated supernatants in different combinations. A repeat Triton extraction was performed, and differential distribution of Na,K-ATPase or HSP-70 was assessed by Western blots and densitometric analysis.
Coincubation of cytoskeletal pellets obtained during early reflow after renal ischemia (exhibiting severe injury of the cytoskeletal anchorage of Na,K-ATPase) and noncytoskeletal supernatant obtained during later reflow (showing high HSP expression) resulted in specific translocation of HSP-70 from the supernatant into the pellet, functionally associated with dose-dependent stabilization of Na,K-ATPase within this cytoskeletal fraction. These effects could be reproduced by incubation with purified HSP-70 and were abolished by the addition of anti–HSP-70 antibodies.
These data support the hypothesis that HSP-70 interacts with cytoskeletal elements during the restoration of proximal tubule cell structure and polarity after renal ischemia. This experimental approach represents a new in vitro assay to study further the role of HSP in cellular repair.