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Hsp72 is neuroprotective in the the anoxia tolerant turtle, Trachemys scripta elegans
Author(s) -
Kesaraju Shailaja,
Prentice Howard M.,
Milton Sarah L.
Publication year - 2007
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.21.6.a1287-b
Subject(s) - gene knockdown , neuroprotection , heat shock protein , biology , propidium iodide , anoxic waters , programmed cell death , cell damage , hsp70 , microbiology and biotechnology , andrology , apoptosis , pharmacology , biochemistry , medicine , gene , ecology
Cardiac ischemia, stroke and some neurodegenerative disorders are all characterized by cell damage and death due to low oxygen levels. Heat shock proteins, Hsp72 in particular, are neuroprotective in species from the fruit fly to humans. While increases in Hsp72 and Hsc73 have been reported in anoxia in the highly anoxia‐tolerant turtle Trachemys scripta , the protective role of these stress proteins in cell death has yet to be determined. We examined the levels of Hsp72 in neuronally enriched primary cell cultures established from the turtle, and utilized siRNA to knockdown Hsp72 in vitro . Hsp72 protein and RNA levels increased during late anoxia (4 hours) and prolonged anoxia (16hour) with respect to normoxic controls. As in the whole brain, significant levels of Hsp72 protein were observed even in normoxia, which increased 2 to 3‐fold after 16 hours of anoxia (P<0.05) indicating a probable role in long‐term anoxic cell survival. SiRNA mediated knockdown of Hsp72 resulted in increased cell death compared to controls in both anoxic cells and following reoxygenation after 4 hours anoxia, as evidenced by Propidium Iodide (PI) staining. Hsp72 knockdown has also resulted in increased ROS release upon reoxygenation (P<0.05) in a dose dependent manner, implicating Hsp72 as a key element of anoxic and reoxygenation cell survival that does play a role in the suppression of ROS production. The mechanisms by which Hsp72 promotes neuronal survival in anoxia and reoxygenation are currently under investigation.