Demonstration of elevated levels of active cathepsin S in dextran sulfate sodium colitis using a new activatable probe

N. Barlow, Y. Nasser, P. Zhao, N. Sharma, R. Guerrero-Alba, L. E. Edgington-Mitchell, T. Lieu, N. A. Veldhuis, D. P. Poole, J. W. Conner, E. Lindström, A. W. Craig, B. Graham, S. J. Vanner, Nigel W. Bunnett

Research output: Contribution to journalArticlepeer-review


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. Key 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 & Inferences: 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.

Original languageEnglish (US)
Pages (from-to)1675-1680
Number of pages6
JournalNeurogastroenterology and Motility
Issue number11
StatePublished - Nov 2015


  • Activatable probes
  • Cathepsin S
  • DSS colitis
  • Inflammation
  • Proteases

ASJC Scopus subject areas

  • Physiology
  • Endocrine and Autonomic Systems
  • Gastroenterology


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