Polyunsaturated fatty acids enhance the heat induced stress response in rainbow trout (Oncorhynchus mykiss) leukocytes.
The heat shock response has been studied extensively, yet the molecular signals that trigger the response remain elusive. The dogma of the heat shock response contends that denatured proteins initiate the response, but evidence is accumulating to point to a more complex system in which at least more than one signal is involved in this process. Thermal stress initiates changes in cellular phospholipid membrane physical state, which when acted upon by phospholipases may release lipid mediators that could serve as triggering signals during the heat shock response. We have examined the heat shock response in freshly isolated leukocytes from the pronephros of rainbow trout (Oncorhynchus mykiss). In this study, we show that leukocytes isolated from rainbow trout acclimated to 5 or 19 degrees C express elevated levels of heat shock protein 70 (hsp70) mRNA when heat shocked at 5 degrees C above their respective acclimation temperature and supplementation with exogenous docosahexaenoic acid or arachidonic acid followed by heat shock enhanced levels of hsp70 mRNA. The time course for docosahexaenoic acid induced enhancement of hsp70 mRNA was accelerated compared with heat shock alone, and staurosporine inhibited the docosahexaenoic acid induced increase of hsp70 mRNA. We also provide evidence that phospholipase A2 is involved in the heat shock response.
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Mountain Aquaculture Research Center, Western Carolina University, Cullowhee, NC 28723, USA. bsamples@wpoff.wcu.edu
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Lumb
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D000818:Animals; D001095:Arachidonic Acids / Q000378:metabolism* / Q000494:pharmacology; D004281:Docosahexaenoic Acids / Q000378:metabolism* / Q000494:pharmacology; D005786:Gene Expression Regulation / Q000187:drug effects; D018840:HSP70 Heat-Shock Proteins / Q000235:genetics*; D018869:Heat-Shock Response / Q000187:drug effects; D006361:Heating; D007962:Leukocytes / Q000187:drug effects / Q000378:metabolism*; D009829:Oleic Acids / Q000378:metabolism* / Q000494:pharmacology; D017686:Oncorhynchus mykiss / Q000097:blood*; D010741:Phospholipases A / Q000378:metabolism / Q000494:pharmacology; D054467:Phospholipases A2; D012333:RNA, Messenger; D013696:Temperature; D013997:Time Factors
D001095:Arachidonic Acids; D018840:HSP70 Heat-Shock Proteins; D009829:Oleic Acids; D012333:RNA, Messenger; D004281:Docosahexaenoic Acids; D010741:Phospholipases A; D054467:Phospholipases A2