Induction and intracellular localization of HSP-72 after renal ischemia.
To determine whether heat shock proteins (HSPs) might be active in cellular recovery following transient ischemia, we examined rat kidneys for 70-kDa HSP (HSP-70) mRNA expression, protein elaboration, and intracellular localization after 45 min of renal ischemia and reflow of 15 min, 2, 6, and 24 h. Inducible HSP-70 mRNA is present at 15 min of reperfusion, peaks between 2 and 6 h, and falls by 24 h. Inducible 72-kDa HSP (HSP-72) protein accumulates progressively through 24 h and is found in both soluble and microsomal fractions following ischemia. Within proximal tubules, immunofluorescent localization of HSP-72 is restricted to the apical domain at 15 min, is dispersed through the cytoplasm in a vesicular pattern at 2 and 6 h, and has migrated away from the apical domain at 24 h. A portion of the vesicular HSP-72 is associated with lysosomes; no intranuclear HSP-72 is detected. The course of mRNA induction, protein elaboration, and HSP-72 localization coincides with previously described changes in proximal tubule morphology and polarity following sublethal ischemic injury. HSP-72 may be instrumental in cellular remodeling and restitution of epithelial polarity during recovery from ischemic renal injury.
Van Why
S K
SK
Department of Pediatrics, Yale University School of Medicine, New Haven, Connecticut 06510.
Hildebrandt
F
F
Ardito
T
T
Mann
A S
AS
Siegel
N J
NJ
Kashgarian
M
M
D000818:Animals; D015152:Blotting, Northern; D015153:Blotting, Western; D006360:Heat-Shock Proteins / Q000378:metabolism*; D007150:Immunohistochemistry; D007425:Intracellular Membranes / Q000378:metabolism*; D007511:Ischemia / Q000378:metabolism*; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D012079:Renal Circulation; D014018:Tissue Distribution
D006360:Heat-Shock Proteins