title: A mouse model for monitoring calpain activity under physiological and pathological conditions.
abstract: Calpains are Ca(2+)-dependent cysteine proteases known to be important for the regulation of cell functions and which aberrant activation causes cell death in a number of degenerative disorders. To provide a tool for monitoring the status of calpain activity in vivo under physiological and pathological conditions, we created a mouse model that expresses ubiquitously a fluorescent reporter consisting of eCFP and eYFP separated by a linker cleavable by the ubiquitous calpains. We named this mouse CAFI for calpain activity monitored by FRET imaging. Our validation studies demonstrated that the level of calpain activity correlates with a decrease in FRET (fluorescence resonance energy transfer) between the two fluorescent proteins. Using this model, we observed a small level of activity after denervation and fasting, a high level of activity during muscle regeneration and ischemia, and local activity in damaged myofibers after exercise. Finally, we crossed the CAFI mouse with the alpha-sarcoglycan-deficient model, demonstrating an increase of calpain activity at the steady state. Altogether, our results present evidence that CAFI mice could be a valuable tool in which to follow calpain activity at physiological levels and in disease states.
authors.affiliation: Généthon/CNRS-UMR8115, 1 rue de l'Internationale 91000 Evry, France.
authors.forename: Marc
authors.initials: M
authors.lastname: Bartoli
authors.forename: Nathalie
authors.initials: N
authors.lastname: Bourg
authors.forename: Daniel
authors.initials: D
authors.lastname: Stockholm
authors.forename: Fabrice
authors.initials: F
authors.lastname: Raynaud
authors.forename: Antony
authors.initials: A
authors.lastname: Delevacque
authors.forename: Yang
authors.initials: Y
authors.lastname: Han
authors.forename: Perrine
authors.initials: P
authors.lastname: Borel
authors.forename: Kenza
authors.initials: K
authors.lastname: Seddik
authors.forename: Nasser
authors.initials: N
authors.lastname: Armande
authors.forename: Isabelle
authors.initials: I
authors.lastname: Richard
mesh_terms: D000818:Animals; D001426:Bacterial Proteins / Q000737:chemistry; D002118:Calcium / Q000378:metabolism; D002154:Calpain / Q000737:chemistry* / Q000378:metabolism; D004195:Disease Models, Animal; D005260:Female; D031541:Fluorescence Resonance Energy Transfer; D017930:Genes, Reporter; D006801:Humans; D008164:Luminescent Proteins / Q000737:chemistry; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008956:Models, Chemical; D008957:Models, Genetic; D019636:Neurodegenerative Diseases / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D008164:Luminescent Proteins; C054562:yellow fluorescent protein, Bacteria; D002154:Calpain; D002118:Calcium