Heat shock protein 27 regulates oxidative stress-induced apoptosis in cardiomyocytes: mechanisms via reactive oxygen species generation and Akt activation / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Increased reactive oxygen species (ROS) formation, which in turn promotes cardiomyocytes apoptosis, is associated with the pathogenesis and progression of various cardiac diseases such as ischemia and heart failure. Recent studies have shown that over expression of heat shock protein 27 (Hsp27) confers resistance to cardiac ischemia/reperfusion injury. However, not much is known about the regulation of myocyte survival by Hsp27.</p><p><b>METHODS</b>The rat cardiac cell line H9c2, with a stable overexpression of Hsp27, was established, with empty vector transfected H9c2 cells as controls. Following the cells challenged by Hydrogen Peroxide (H2O2), lactate dehydrogenase (LDH) release, apoptosis, intracellular ROS, cell morphology, mitochondrial transmembrane potential and the activation of serine/threonine kinase Akt were determined.</p><p><b>RESULTS</b>Along with marked suppression of H2O2-induced injury by Hsp27 overexpression in H9c2 cells, ROS generation and the loss of mitochondrial membrane potential were also significantly depressed. Furthermore, augmented Akt activation was observed in Hsp27 overexpressed H9c2 cells following H2O2 exposure.</p><p><b>CONCLUSIONS</b>Hsp27 inhibits oxidative stress-induced H9c2 damage and inhibition of ROS generation and the augmentation of Akt activation may be involved in the protective signaling.</p>

Generation of Transgenic Mice with Cardiac-specific Overexpressing Heat Shock Protein 27 / 中国生物工程杂志

Objective:Increased reactive oxygen species (ROS) formation and by which in turn promotes cardiomyocytes apoptosis is associated with the pathogenesis and progression of various cardiac diseases. Small heat shock protein 27(Hsp27) could protect different cells from oxidative damage. By using tissue nonspecific overexpression Hsp 27 transgenic model, other investigators demonstrated that Hsp27 suppressed successfully kainate-induced seizures and hippocampal cell death in intact transgenic mice, and attenuated mimic ischemia/reperfusion injury in Langendorff-perfused isolated mice heart. As there are complicated and long distance neuro-humoral regulation associated with the development of cardiac diseases, it is better to choose a cardiac-specific overexpression transgenic model to study the effects of Hsp27 in hearts in vivo.Methods:A cDNA encoding human Hsp27 was subcloned into pBSII-SK+ containing the ?-myosin heavy chain (?-MHC) promoter (generously provided by Dr. J. Robbins, Children’s Hospital of Cincinnati, Ohio). BamHI-digested linear transgene consistent with the ?-MHC promoter, Hsp27 cDNA, and poly (A) of human growth hormone (hGH) was microinjected into the fertilized eggs from CBA/BL6 mice. Mice containing the transgene were identified by polymerase chain reaction. Founders revealed by this screening were used to establish independent transgenic lines. Following successful transmission, a range of tissues including heart, lung, liver, brain, skeleton muscle, spleen and kidney was screened by Western blot to confirm the cardiac specific expression of the transgene. Results and Discussion:Transgenic mice expressed Hsp27 under the control of a-MHC promoter. Cardiac tissues from independent TG line expressed abundant Hsp27, and as expected, Hsp27 expressed in cardiac tissues only, whereas none in liver, spleen, lung, kidney, brain and skeleton muscle. Surprisingly, Hsp25, the endogenous isoform of Hsp27 in murine, was downregulated by Hsp27 overexpression (data not shown), which is in contrast to the result of Hollander’s [1]. It needs to determine in future whether Hsp27 expression profile in heart could exert any effect on the regulation of Hsp25.Conclusion: The TG mice overexpression human Hsp27 specifically in the heart by using ?MHC- promotor were created. All TG mice expressed Hsp27 abundantly and cardiac-specifically. To our knowledge, it is the first report of creation of transgenic mice which overexpressing Hsp27 cardiac specifically. This current model suggests that the Hsp27 cardiac-specific over-expression of transgenic mouse remains a robust genetic tool for dissecting molecular and genetic events involving Hsp27, which could be a therapeutic target in heart failure.

Overexpression of heat-shock proteins B1 protected rat cardiac cell line H9c2 from H_2O_2-induced oxidative damage / 中华老年医学杂志

Objective To determine the effect of mitochondria on the protection of heat-shock proteins B1(HSPB1) from oxidative damage in rat cardiac cell.Methods HSPB1 gene-transfected rat cardiomyocytes cell line H9c2 (HSPB1 H9c2) and empty vector transfected H9c2 (control) were established,and treated by 0-1000?mol/L H_2O_2 for 2h.And then the cell morphology, mitochondrial membrane potential and endogenous reactive oxygen species (ROS) were detected. Results (1)HSPB1 inhibited the morphological changes induced by H_2O_2 markedly.(2)HSPB1 inhibited the loss of mitochondrial membrane potential induced by H_2O_2.Following the stimulation of 0,75,150,300,500,1000?mol/L H_2O_2,mitochondrial membrane potential in HSPB1 and control H9c2 cells were (10.0?0.11)vs (7.01?0.26),(9.11?0.17)vs (6.05?0.19),(7.69?0.28)vs (5.14?0.28),(6.95?0.13)vs (4.66?0.11),(6.61?0.20)vs (1.85?0.35),(6.60?0.05)vs (1.19?0.01),respectively (all P0.05).Conclusions HSPB1 protects rat cardiomyocytes cell line(H9c2) from oxidative damage,which suggests that stabilization of mitochondrial membrane potential and the decreased endogenous reactive oxygen species after oxidative stress may be involved in the protection of HSPB1 against oxidative stress in H9c2.