The Protective Effects And Mechanisms Of Selective Histone Deacetylase 6 Inhibitor ACY-1215 On Acute Liver Failure In Mice

Part? ACY-1215 suppressed inflammatory response in acute liver failure mice by regulating the TLR4-MAPK/NF-kB pathwayObjective: Histone deacetylase 6(HDAC6)is considered a new target for anticancer,anti-inflammatory,and neurodegenerative treatment.ACY-1215 is a selective histone deacetylase 6 inhibitor,and it has been recognized as a potential anticancer and anti-inflammation drug.The aim of our study was to investigate whether ACY-1215 has protective effects on acute liver failure(ALF)in mice and explore its potential mechanism.Methods: Male C57/BL6 mice were divided into normal,model,and ACY-1215 groups.ACY-1215(25 mg/kg)and same amounts of saline were given to mice.After 2 h,the ALF models were induced by lipopolysaccharide(LPS,100 ?g/kg)combined with D-galactosamine(400 mg/kg).All animals were sacrificed after 24 h.The expressions of HDAC6 were determined by western blotting and RT-PCR assay.The expression levels of inflammatory cytokines were detected by RT-PCR.The protein expression of Toll-like receptor 4(TLR4),mitogen-activated protein kinase(MAPK),and nuclear factor ?B(NF-?B)species were determined by western blot.Results: The mortality of mice with ALF induced by LPS and D-gal was significantly decreased by ACY-1215 pretreatment.Procedures to manage ALF caused severely injuried liver histology and function.This damage was repaired by pretreatment of ACY-1215.ACY-1215 treatment also attenuated the RNA levels of the pro-inflammatory cytokines.Pretreatment of ACY-1215 significantly decreased the protein expression of TLR4 and the activation of MAPK and NF-?B signaling pathways.Conclusion: ACY-1215 has potential therapeutic value in mice with ALF by directly inhibiting inflammatory response through regulation of the TLR4-MAPK/NF-kB pathway.Part? The protective effects of ACY-1215 on necrosis of hepatocytes in mice with acute liver failureObjective: Acute liver failure(ALF)is a clinical syndrome accompanied by massive hepatocyte necrosis and liver dysfunction.ACY-1215 is a well-known selective histone deacetylase 6(HDAC6)inhibitor and it has been recognized as a potential therapeutic drug in inflammatory diseases.However,it is not well known about the impact of ACY-1215 treatment on the necrosis of hepatocytes in acute liver failure(ALF)at present.The aim of our study was to investigate whether ACY-1215 has inhibitory effects on the necrosis of hepatocytes in ALF mice and explore its potential mechanism.Methods: Male C57/BL6 mice were divided into normal,model,and ACY-1215 groups.ACY-1215(25 mg/kg)and same amounts of saline were injected intraperitoneally to mice before the establishment of ALF model induced by LPS(100 ?g/kg)combined with D-galactosamine(400 mg/kg).All animals were sacrificed after 24 h.In this study,detection programs including quantitative proteomic analysis,transmission electron microscopy(TEM)micrographs,pathological staining,protein expression as well as biochemical assay.Results: The necrosis of hepatocytes in ALF mice were significantly normalized by ACY-1215 pretreatment.The quantitative proteomics analysis revealed that ACY-1215 restrained oxidative phosphorylation by normalizing the function respiratory electron-transport chain in mitochondria.Moreover,pretreatment of ACY-1215 not only normalized the structure of mitochondria,but also inhibited the generation of ROS.Conclusion: ACY-1215 was able to inhibit necrosis of hepatocytes in ALF mice through regulating the mitochondrial-mediated oxidative stress,Part ? Inhibition of the expression of histone deacetylase 6 attenuates the inflammatory response in LPS-activated macrophagesObjective: Macrophage activation plays an important role in the pathogenesis of acute liver failure,which could aggravate the inflammatory response and the hepatocyte necrosis.Histone deacetylase 6(HDAC6)has been considered as an important regulator in the development of inflammatory diseases.However,the mechanisms of HDAC6 in regulating in regulating inflammatory responses were not fully clear.In the present study,we aim to investigate the role and mechanisms of HDAC6 in regulating inflammation in lipopolysaccharide(LPS)-activated macrophages.Methods: Flow cytometry was used to determine a suitable treatment dosage of ACY-1215 on LPS-activated macrophages for the present study.The RAW264.7 macrophages were divided into normal,LPS-treated,and ACY-1215 treated groups,respectively.For the ACY-1215 group,ACY-1215(10 ?M)was added to the medium 2 h prior to treatment with LPS(1 ?g/ml)for 24 hours.In this study,detection programs included biochemical assay,m RNA and protein expression assay.Subsequently,the effect of HDAC6 knockdown on inflammatory response in LPS-activated RAW264.7 macrophages was also detected.Results: With the stimulation of LPS,the expression of pro-inflammatory cytokines such as TNF-?,IL-1?,and IL-6 were enhanced,and the production of reactive oxygen species(ROS)was also increased.ACY-1215 or knockdown of HDAC6 inhibited the generation of ROS and suppressed LPS-induced pro-inflammatory cytokines in macrophages.In addition,the protein expression of TLR4 and the activation of MAPK and NF-?B signaling pathways were normalized by the pretreatment of ACY-1215 or knockdown of HDAC6.Conclusion: Inhibition of the expression of HDAC6 exhibited protective role against LPS-induced inflammatory response in RAW264.7 cells through regulating the activation of TLR4-ROS-MAPK-NF-?B signaling pathway.