title: Inhibition of histone deacetylase 6 improves long-term survival in a lethal septic model.
abstract: BACKGROUND
  We recently demonstrated that suberoylanilide hydroxamic acid, a broad-spectrum histone deacetylase (HDAC) inhibitor that inhibits HDACs 1, 2, 3, and 6, improves survival in a mouse model of cecal ligation and puncture (CLP)-induced lethal sepsis. The current study was undertaken to determine the effect of selective inhibition of HDAC isoform on survival, key cytokine production, organ injury, bacteria clearance, and cell apoptosis.
  
  
  METHODS
  In Experiment 1, C57BL/6J mice were subjected to CLP and, 1 hour later, given intraperitoneal injections of (1) Tubastatin A (inhibitor of HDAC6) dissolved in dimethyl sulfoxide (DMSO), (2) MS-275 (inhibitor of HDACs 1, 2, and 3) in DMSO, and (3) DMSO only. Survival was monitored for 10 days. In Experiment 2, 1 hour after CLP, animals were treated with DMSO vehicle or Tubastatin A. Sham-operated animals served as control. Peritoneal fluid and blood samples were collected for measurement of cytokines at 24 hours or 48 hours. Blood at 48 hours was also used to determine bacteria load. Liver was harvested to evaluate acute liver injury. In Experiment 3, Primary splenocytes were used to assess cytokine responses and phagocytosis. Macrophages were cultured and harvested 3 hours and 6 hours after lipopolysaccharide stimulation in the absence or presence of Tubastatin A to analyze cell apoptosis.
  
  
  RESULTS
  Animals treated with Tubastatin A, but not MS-275, displayed a significant improvement in survival. Moreover, Tubastatin A significantly inhibited cytokine production in peritoneal fluid and plasma as well as in supernatant from splenocytes stimulated with lipopolysaccharide. Tubastatin A significantly attenuated acute liver injury, increased blood bacteria clearance and splenocyte phagocytosis, and decreased macrophage apoptosis.
  
  
  CONCLUSIONS
  HDAC6 inhibition significantly improves survival, reduces "cytokine storm," attenuates acute livery injury, increases bacteria clearance and immune cell phagocytosis, and inhibits macrophage apoptosis in a lethal mouse CLP model.
authors.affiliation: From the General Surgery (Y.L., T.Z., B.L., I.H., H.B.A.), Department of Surgery, University of Michigan Hospital, Ann Arbor, Michigan; Center for Systems Biology (R.M.), Massachusetts General Hospital, Boston; and Chemical Biology Program (R.M.), the Broad Institute of Harvard and MIT, Cambridge, Massachusetts; and Department of Pathology (X.D.), Loyola University Medical Center, Maywood, Illinois.
authors.forename: Yongqing
authors.initials: Y
authors.lastname: Li
authors.forename: Ting
authors.initials: T
authors.lastname: Zhao
authors.forename: Baoling
authors.initials: B
authors.lastname: Liu
authors.forename: Ihab
authors.initials: I
authors.lastname: Halaweish
authors.forename: Ralph
authors.initials: R
authors.lastname: Mazitschek
authors.forename: Xiuzhen
authors.initials: X
authors.lastname: Duan
authors.forename: Hasan B
authors.initials: HB
authors.lastname: Alam
mesh_terms: D000818:Animals; D001549:Benzamides / Q000494:pharmacology*; D015153:Blotting, Western; D016207:Cytokines / Q000032:analysis; D004121:Dimethyl Sulfoxide / Q000494:pharmacology; D004195:Disease Models, Animal; D004797:Enzyme-Linked Immunosorbent Assay; D005434:Flow Cytometry; D056572:Histone Deacetylase Inhibitors / Q000494:pharmacology*; D006877:Hydroxamic Acids / Q000494:pharmacology*; D007211:Indoles / Q000494:pharmacology*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D010587:Phagocytosis; D011725:Pyridines / Q000494:pharmacology*; D011897:Random Allocation; D018805:Sepsis / Q000188:drug therapy*; D015996:Survival Rate
chemical_list: D001549:Benzamides; D016207:Cytokines; D056572:Histone Deacetylase Inhibitors; D006877:Hydroxamic Acids; D007211:Indoles; D011725:Pyridines; C118739:entinostat; C553587:tubastatin A; D004121:Dimethyl Sulfoxide