Heat shock protein 70 overexpression protects LLC-PK1 tubular cells from heat shock but not hypoxia.
BACKGROUND
Overexpression of the 70 kDa heat shock protein (Hsp70) protects myocytes and neural cells from hypoxic injury. In contrast, Hsp70 induction in the kidney after ischemic or thermal preconditioning does not correlate well with protection from hypoxic injury. Herein, we directly tested if Hsp70 overexpression protects LLC-PK1 porcine tubular epithelial cells from hypoxic or thermal injury.


METHODS
LLC-PK1 cells were either cotransfected with an Hsp70 and a luciferase expression vector or singly transfected with the luciferase expression vector. Loss of intracellular luciferase activity was used to assess injury after exposure to hypoxia or hyperthermia and after recovery under normal growth conditions.


RESULTS
Overexpression of Hsp70 decreased loss of and improved restoration of intracellular luciferase activity in LLC-PK1 cells exposed to hyperthermia. In contrast, Hsp70 overexpression did not decrease the loss of or improve restoration of luciferase activity in cells exposed to hypoxia.


CONCLUSIONS
These results suggest that Hsp70 overexpression is sufficient to protect LLC-PK1 proximal tubular cells from hyperthermia but is not sufficient for protection from hypoxia.
Turman
M A
MA
Department of Pediatrics, The Ohio State University and the Wexner Institute for Pediatric Research, Children's Hospital, Columbus, Ohio, USA. mturman@chi.osu.edu
Rosenfeld
S L
SL
D000818:Animals; D015687:Cell Hypoxia / Q000235:genetics; D015870:Gene Expression; D017930:Genes, Reporter; D018840:HSP70 Heat-Shock Proteins / Q000235:genetics* / Q000378:metabolism; D006358:Hot Temperature; D007150:Immunohistochemistry; D007684:Kidney Tubules / Q000378:metabolism*; D018374:LLC-PK1 Cells; D008156:Luciferases / Q000235:genetics / Q000378:metabolism; D013552:Swine; D014162:Transfection
D018840:HSP70 Heat-Shock Proteins; D008156:Luciferases