title: Heat Stress Induces Extended Plateau of Hsp70 Accumulation--A Possible Cytoprotection Mechanism in Hepatic Cells.
abstract: The relevance of heat preconditioning resides in its ability to protect cells from different kinds of injury by induction of heat shock proteins, a process in which the intensity of heat stress (HS) and duration of subsequent recovery are vital. This study evaluates the effects of moderate HS (45 min/43°C) and the time-dependent changes during recovery period of HSP70, Bcl-2 and p53 gene and protein expression in HepG2 cells. We also evaluated the effects of 0.4 mM aspirin (ASA) as a potential pharmacological co-inducer of HSP, both alone and in a combination with HS (ASA + HS). HS alone and ASA + HS caused a major up-regulation of HSP70 mRNA in the first 2 h, while HSP70 protein increased gradually and was especially abundant from 2 h to 24 h. Regarding Bcl-2, all treatments rendered similar results: gene expression was down-regulated in the first 2 h, after which there was protein elevation (12-48 h after HS). mRNA expression of p53 in HS- and (ASA + HS)-cells was down-regulated in the first 12 h. The immediate decrease of p53 protein after HS was followed by a biphasic increase. In conclusion, 0.4 mM ASA + HS does not act as a co-inducer of HSP70 in HepG2 cells, but promotes Bcl-2 protein expression during prolonged treatment. Our suggestion is that hepatic cells are most vulnerable in the first 2-6 h, but may have a high capacity for combating stress 12-24 h after HS. Finally, short-term exposure HS might be a "physiological conditioner" for liver cells to accumulate HSP and Bcl-2 proteins and thus obtain cytoprotection against an additional stress.
authors: Department of Physiology and Biochemistry, Institute of Biology, Faculty of Natural Sciences and Mathematics, University "St Cyril and Methodius,", 1000, Skopje, Republic of Macedonia.
authors: Biljana
authors: B
authors: Miova
authors: Department of Physiology and Biochemistry, Institute of Biology, Faculty of Natural Sciences and Mathematics, University "St Cyril and Methodius,", 1000, Skopje, Republic of Macedonia.
authors: Suzana
authors: S
authors: Dinevska-Kjovkarovska
authors: Departamento de Farmacolog, í, a, Facultad de Medicina- CIBERehd, Universidad de Valencia, Valencia, Spain.|FISABIO-Hospital Universitario Dr. Peset, Valencia, Spain.
authors: Juan V
authors: JV
authors: Esplugues
authors: Departamento de Farmacolog, í, a, Facultad de Medicina- CIBERehd, Universidad de Valencia, Valencia, Spain.|FISABIO-Hospital Universitario Dr. Peset, Valencia, Spain.|Facultad de Ciencias de la Salud, Universitat Jaume I, Castell, o, n de la Plana, Spain.
authors: Nadezda
authors: N
authors: Apostolova
mesh_terms: D001241:Aspirin / Q000008:administration & dosage; D019610:Cytoprotection / Q000235:genetics; D005786:Gene Expression Regulation / Q000187:drug effects; D018840:HSP70 Heat-Shock Proteins / Q000096:biosynthesis* / Q000235:genetics; D018869:Heat-Shock Response / Q000235:genetics*; D056945:Hep G2 Cells; D022781:Hepatocytes / Q000378:metabolism; D006358:Hot Temperature; D006801:Humans; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000096:biosynthesis* / Q000235:genetics; D012333:RNA, Messenger / Q000096:biosynthesis; D016159:Tumor Suppressor Protein p53 / Q000096:biosynthesis* / Q000235:genetics
chemical_list: D018840:HSP70 Heat-Shock Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; D012333:RNA, Messenger; C495901:TP53 protein, human; D016159:Tumor Suppressor Protein p53; D001241:Aspirin
keywords: ASPIRIN; HEAT PRECONDITIONING; HSP70; LIVER REGENERATION