ABSTRACT
BACKGROUND: The conversion of a quiescent vitamin A storing hepatic stellate cell (HSC) to a matrix producing, contractile myofibroblast-like activated HSC is a key event in the onset of liver disease following injury of any aetiology. Previous studies have shown that class I histone deacetylases (HDACs) are involved in the phenotypical changes occurring during stellate cell activation in liver and pancreas. AIMS: In the current study we investigate the role of class II HDACs during HSC activation. METHODS: We characterized the expression of the class II HDACs freshly isolated mouse HSCs. We inhibited HDAC activity by selective pharmacological inhibition with MC1568, and by repressing class II HDAC gene expression using specific siRNAs. RESULTS: Inhibition of HDAC activity leads to a strong reduction of HSC activation markers α-SMA, lysyl oxidase and collagens as well as an inhibition of cell proliferation. Knock down experiments showed that HDAC4 contributes to HSC activation by regulating lysyl oxidase expression. In addition, we observed a strong up regulation of miR-29, a well-known anti-fibrotic miR, upon treatment with MC1568. Our in vivo work suggests that a successful inhibition of class II HDACs could be promising for development of future anti-fibrotic compounds. CONCLUSIONS: In conclusion, the use of MC1568 has enabled us to identify a role for class II HDACs regulating miR-29 during HSC activation.
Subject(s)
Gene Expression Regulation/drug effects , Hepatic Stellate Cells/drug effects , Hepatic Stellate Cells/metabolism , Histone Deacetylase Inhibitors/pharmacology , Histone Deacetylases/metabolism , MicroRNAs/genetics , Animals , Carbon Tetrachloride/adverse effects , Disease Models, Animal , Gene Expression Profiling , Gene Knockdown Techniques , Histone Deacetylase Inhibitors/administration & dosage , Histone Deacetylases/genetics , Hydroxamic Acids/administration & dosage , Hydroxamic Acids/pharmacology , Liver/cytology , Liver/drug effects , Liver/metabolism , Liver Cirrhosis, Experimental/chemically induced , Liver Cirrhosis, Experimental/drug therapy , Liver Cirrhosis, Experimental/metabolism , Male , Mice , Pyrroles/administration & dosage , Pyrroles/pharmacology , RNA InterferenceABSTRACT
BACKGROUND: Heat shock proteins (Hsp) are ubiquitously synthesised in virtually all species and it is hypothesised that they might have beneficial health effects. Recent studies have identified circulating Hsp as an important mediator in inflammation - the effects of low-grade inflammation in the aging process are overwhelming. While much is known about intracellular Hsp70, scant data exist on circulating Hsp70 in the aging context. Therefore, the objectives of this study were to investigate the effect of age and disease on circulating Hsp70 and, in particular, to evaluate the association between circulating Hsp70 and inflammatory parameters. RESULTS: Serum Hsp70, Interleukin (IL) -10, IL-6 and Tumor Necrosis Factor (TNF) alpha concentrations were determined in 90 hospitalised geriatric patients (aged 83 ± 6 years) and in 200 community-dwelling control subjects (100 elderly, aged 74 ± 5 years, and 100 young, aged 23 ± 3 years). In the community-dwelling elderly, serum Hsp70 and IL-10 concentrations were significantly lower and IL-6 was significantly higher when compared to healthy young control subjects. Elderly patients presenting inflammation (CRP serum levels ≥5 mg/L) showed significantly (p = 0.007) higher Hsp70 values; and Hsp70 correlated positively (p < 0.001) with IL-6 and CRP, but not with TNF-alpha or IL-10. A significant association was also noted between Hsp70 levels and the degree of dependency and cognitive decline in geriatric patients. CONCLUSIONS: The present data provide new evidence that serum concentration of Hsp70 decreases with age in a normal population. Our study also shows that higher levels of Hsp70 are associated with inflammation and frailty in elderly patients.