Demonstrated ischemic protection of cytoskeleton by specific heat shock proteins

Objective: To examine protection of cytoskeletal proteins by specific heat shock proteins during ischemia

Background: The overall protective effects of heat shock proteins during cardiac ischemia are now well documented. However, less is known about the mechanisms of protection or the specificity of different heat shock proteins. Associations between heat shock proteins and cytoskeletal proteins have been reported, leading to the hypothesis of specific cytoskeletal protection by heat shock proteins.

Methods: Heat shock proteins (inducible Hsp70i, constitutive Hsp70c, Hsp27, aB-crystallin) were overexpressed in rat neonatal cardiac myocytes by adenoviral infection. After 2 days, cells were subjected to 14 hours of simulated ischemia. The integrity of cytoskeletal proteins (e.g., tubulin) was analyzed by indirect immunofluorescence, confocal microscopy, and quantitative image analysis.

Results: Damage to tubulin during simulated ischemia was reduced by overexpression of constitutive Hsp70c or a B-crystallin, but not by overexpression of inducible Hsp70i or Hsp27 (Am. J. Physiol. 275: H2243-H2249, 1998. - ABSTRACT). Additional studies are in progress.