Cardiovascular Division, University of California, Davis, CA 95616, USA.
J Mol Cell Cardiol. 2010 Feb;48(2):360-6. doi: 10.1016/j.yjmcc.2009.11.009. Epub 2009 Nov 27.
Heart failure, a progressive, fatal disease of the heart muscle, is a state of chronic inflammation and injury. Heat shock protein (HSP) 72, a ubiquitous protective protein that is well-established as cardioprotective, is not increased in heart failure. In contrast, HSP60 levels are doubled in the failing heart. We hypothesized that HSF-1 is not activated in heart failure and that the increased expression of HSP60 was driven by NFkappaB activation. To test this hypothesis, we measured levels of heat shock factor (HSF) -1 and -2, the transcription factors controlling HSP expression, which were increased in heart failure. There was no increased phosphorylation of serine 230 or serine 303/307 in HSF-1, which are thought to regulate its activity; EMSA showed no increase in HSF binding activity with heart failure. Nonetheless, mRNA was increased for HSP60, but not HSP72. In contrast to HSF, NFkappaB activity was increased in heart failure. HSP60, but not HSP72, contained NFkappaB binding elements. ChIP assay demonstrated increased binding of NFkappaB to both of the NFkappaB binding elements in the heart failure HSP60 gene. TNFalpha treatment was used to test the role of NFkappaB activation in HSP60 expression in a cardiac cell line. TNFalpha increased HSP60 expression, and this could be prevented by pretreatment with siRNA inhibiting p65 expression. In conclusion, HSP72 is not increased in heart failure because HSF activity is not changed; increased expression of HSP60 may be driven by NFkappaB activation.
心力衰竭是一种进行性、致命性的心肌疾病，是一种慢性炎症和损伤状态。热休克蛋白 (HSP) 72 是一种普遍存在的保护蛋白，已被证实具有心脏保护作用，但在心力衰竭中并未增加。相比之下，HSP60 的水平在衰竭的心脏中增加了一倍。我们假设 HSF-1 在心力衰竭中未被激活，并且 HSP60 的表达增加是由 NFkappaB 激活驱动的。为了验证这一假设，我们测量了控制 HSP 表达的转录因子热休克因子 (HSF)-1 和 -2 的水平，这些因子在心力衰竭中增加。HSF-1 丝氨酸 230 或丝氨酸 303/307 的磷酸化没有增加，这被认为是调节其活性的因素；EMSA 显示心力衰竭时 HSF 结合活性没有增加。尽管如此，HSP60 的 mRNA 增加了，但 HSP72 没有增加。与 HSF 相反，NFkappaB 活性在心力衰竭中增加。HSP60 而不是 HSP72 含有 NFkappaB 结合元件。ChIP 测定显示 NFkappaB 与心力衰竭 HSP60 基因中的两个 NFkappaB 结合元件的结合增加。使用 TNFalpha 处理来测试 NFkappaB 激活在心脏细胞系中 HSP60 表达中的作用。TNFalpha 增加了 HSP60 的表达，而用 siRNA 抑制 p65 表达预处理可以防止这种情况发生。总之，心力衰竭中 HSP72 没有增加，因为 HSF 活性没有改变；HSP60 的表达增加可能是由 NFkappaB 激活驱动的。
