title: Demonstration of elevated levels of active cathepsin S in dextran sulfate sodium colitis using a new activatable probe.
abstract: BACKGROUND
  Proteases play a major role in inflammatory diseases of the gastrointestinal tract. Activatable probes are a major technological advance, enabling sensitive detection of active proteases in tissue samples. Our aim was to synthesize an activatable probe for cathepsin S and validate its use in a mouse model of colitis.
  
  
  METHODS
  We designed and synthesized a new fluorescent activatable probe, NB200, for the detection of active cathepsin S. Colitis was induced in C57BL/6 mice by the administration of 3% dextran sulfate sodium (DSS). Homogenized mouse colons, with or without the addition of the specific cathepsin S inhibitor MV026031, were incubated with NB200 in a fluorescent plate reader.
  
  
  RESULTS
  NB200 selectively detected purified cathepsin S and not other common inflammatory proteases. Homogenates of colon from mice with DSS colitis induced a significant fluorescent increase when compared to control animals (control vs DSS: p < 0.05 at 200 min and p < 0.01 at 220-240 min), indicating cathepsin S activation. The cathepsin S inhibitor abolished this increase in fluorescence (DSS vs DSS + MV026031: p < 0.05 at 140 min, p < 0.01 at 180 min, p < 0.001 at 200-240 min), which confirms cathepsin S activation. Cathepsin S activity correlated with the disease activity index (Spearman r = 0.77, p = 0.017).
  
  
  CONCLUSIONS
  Our investigation has demonstrated the utility of activatable probes for detecting protease activity in intestinal inflammation. Panels of such probes may allow 'signature' protease profiles to be established for a range of inflammatory diseases and disorders.
authors: Monash Institute of Pharmaceutical Sciences Parkville Australia, Parkville, Vic., Australia.
authors: N
authors: N
authors: Barlow
authors: Gastrointestinal Diseases Research Unit, Division of Gastroenterology, Queen's University, Kingston, ON, Canada.
authors: Y
authors: Y
authors: Nasser
authors: Monash Institute of Pharmaceutical Sciences Parkville Australia, Parkville, Vic., Australia.
authors: P
authors: P
authors: Zhao
authors: Department of Biomedical and Molecular Sciences, Queen's University, Kingston, ON, Canada.
authors: N
authors: N
authors: Sharma
authors: Gastrointestinal Diseases Research Unit, Division of Gastroenterology, Queen's University, Kingston, ON, Canada.
authors: R
authors: R
authors: Guerrero-Alba
authors: Monash Institute of Pharmaceutical Sciences Parkville Australia, Parkville, Vic., Australia.
authors: L E
authors: LE
authors: Edgington-Mitchell
authors: Monash Institute of Pharmaceutical Sciences Parkville Australia, Parkville, Vic., Australia.
authors: T
authors: T
authors: Lieu
authors: Monash Institute of Pharmaceutical Sciences Parkville Australia, Parkville, Vic., Australia.
authors: N A
authors: NA
authors: Veldhuis
authors: Monash Institute of Pharmaceutical Sciences Parkville Australia, Parkville, Vic., Australia.|Department of Anatomy and Neuroscience, University of Melbourne, Parkville, Vic., Australia.
authors: D P
authors: DP
authors: Poole
authors: Monash Institute of Pharmaceutical Sciences Parkville Australia, Parkville, Vic., Australia.
authors: J W
authors: JW
authors: Conner
authors: Medivir AB, Huddinge, Sweden.
authors: E
authors: E
authors: Lindström
authors: Department of Biomedical and Molecular Sciences, Queen's University, Kingston, ON, Canada.
authors: A W
authors: AW
authors: Craig
authors: Monash Institute of Pharmaceutical Sciences Parkville Australia, Parkville, Vic., Australia.
authors: B
authors: B
authors: Graham
authors: Gastrointestinal Diseases Research Unit, Division of Gastroenterology, Queen's University, Kingston, ON, Canada.
authors: S J
authors: SJ
authors: Vanner
authors: Monash Institute of Pharmaceutical Sciences Parkville Australia, Parkville, Vic., Australia.
authors: N W
authors: NW
authors: Bunnett
mesh_terms: D000818:Animals; D002403:Cathepsins / Q000032:analysis*; D003092:Colitis / Q000139:chemically induced / Q000201:enzymology*; D016264:Dextran Sulfate / Q000633:toxicity; D004195:Disease Models, Animal; D005456:Fluorescent Dyes / Q000138:chemical synthesis* / Q000494:pharmacology*; D051379:Mice; D008810:Mice, Inbred C57BL
chemical_list: D005456:Fluorescent Dyes; D016264:Dextran Sulfate; D002403:Cathepsins; C028217:cathepsin S
keywords: DSS colitis; activatable probes; cathepsin S; inflammation; proteases