title: Anchored FRET sensors detect local caspase activation prior to neuronal degeneration.
abstract: BACKGROUND
  Recent studies indicate local caspase activation in dendrites or axons during development and in neurodegenerative disorders such as Alzheimer's disease (AD). Emerging evidences point to soluble oligomeric amyloid-β peptide as a causative agent in AD.
  
  
  RESULTS
  Here we describe the design of fluorescence resonance energy transfer (FRET)-based caspase sensors, fused to the microtubule associated protein tau. Specific caspase sensors preferentially cleaved by caspase-3, -6 or -9 were expressed in differentiated human neuroblastoma SH-SY5Y cells. The anchoring of the sensors resulted in high FRET signals both in extended neurites and soma and made analysis of spatiotemporal signal propagation possible. Caspase activation was detected as loss of FRET after exposure to different stimuli. Interestingly, after staurosporine treatment caspase-6 activation was significantly delayed in neurites compared to cell bodies. In addition, we show that exposure to oligomer-enriched amyloid-β peptide resulted in loss of FRET in cells expressing sensors for caspase-3 and -6, but not -9, in both soma and neurites before neurite degeneration was observed.
  
  
  CONCLUSIONS
  Taken together, the results show that by using anchored FRET sensors it is possible to detect stimuli-dependent differential activation of caspases and to distinguish local from global caspase activation in live neuronal cells. Furthermore, in these cells oligomer-enriched amyloid-β peptide induces a global, rather than local activation of caspase-3 and -6, which subsequently leads to neuronal cell death.
authors: Department of Neurochemistry, Stockholm University, SE-106 91 Stockholm, Sweden. kerstin@neurochem.su.se.
authors: Ricardo A
authors: RA
authors: Figueroa
authors: Veronica
authors: V
authors: Ramberg
authors: Tom
authors: T
authors: Gatsinzi
authors: Malin
authors: M
authors: Samuelsson
authors: Mu
authors: M
authors: Zhang
authors: Kerstin
authors: K
authors: Iverfeldt
authors: Einar
authors: E
authors: Hallberg
references: Mol Cell Proteomics. 2008 Aug;7(8):1541-55
references: 18487604
references: Science. 2001 Apr 27;292(5517):727-30
references: 11326099
references: Cell. 1998 Aug 7;94(3):325-37
references: 9708735
references: Cell. 1997 Nov 14;91(4):479-89
references: 9390557
references: Cell Death Differ. 2000 Mar;7(3):250-61
references: 10745270
references: J Biol Chem. 2003 Mar 28;278(13):11612-22
references: 12499373
references: Nat Rev Mol Cell Biol. 2007 Feb;8(2):101-12
references: 17245412
references: Cell. 1998 Aug 7;94(3):339-52
references: 9708736
references: Neurobiol Dis. 2002 Nov;11(2):341-54
references: 12505426
references: Nat Med. 2000 Apr;6(4):397-404
references: 10742146
references: Nat Neurosci. 2004 Nov;7(11):1181-3
references: 15475950
references: Nature. 2009 Feb 19;457(7232):981-9
references: 19225519
references: Br J Cancer. 1972 Aug;26(4):239-57
references: 4561027
references: Proc Natl Acad Sci U S A. 1996 Aug 6;93(16):8395-400
references: 8710882
references: Nat Biotechnol. 2006 Jan;24(1):95-9
references: 16369538
references: Mol Neurobiol. 1995 Feb;10(1):19-45
references: 7598831
references: J Biol Chem. 2002 Sep 13;277(37):34287-94
references: 12097332
references: Neurobiol Dis. 1998 Nov;5(5):365-78
references: 10069579
references: Cell. 2000 May 12;101(4):389-99
references: 10830166
references: Neuropharmacology. 1997 Jun;36(6):811-21
references: 9225309
references: J Neuropathol Exp Neurol. 2009 Dec;68(12):1282-93
references: 19915487
references: Exp Neurol. 1999 Mar;156(1):100-10
references: 10192781
references: J Neurosci. 2008 Feb 13;28(7):1682-7
references: 18272688
references: Proc Natl Acad Sci U S A. 1995 Sep 26;92(20):9042-6
references: 7568069
references: J Neurochem. 2007 Jun;101(5):1172-84
references: 17286590
references: J Neurochem. 2002 Jan;80(1):126-39
references: 11796751
references: Brain Res Brain Res Rev. 2000 Aug;33(1):95-130
references: 10967355
references: Am J Pathol. 2004 Aug;165(2):523-31
references: 15277226
references: Science. 2002 May 3;296(5569):868-71
references: 11988563
references: Nat Neurosci. 2011 Jan;14(1):69-76
references: 21151119
references: Nature. 2000 Jan 6;403(6765):98-103
references: 10638761
references: J Neurosci. 2007 Jan 24;27(4):893-900
references: 17251431
references: Proc Natl Acad Sci U S A. 2003 Sep 2;100(18):10417-22
references: 12925731
references: J Neurosci. 2004 Nov 10;24(45):10191-200
references: 15537891
references: Nat Neurosci. 2006 Oct;9(10):1234-6
references: 16980964
references: J Biol Chem. 2002 Jun 14;277(24):21836-42
references: 11919205
references: Nat Rev Mol Cell Biol. 2008 Mar;9(3):231-41
references: 18073771
references: Nature. 2004 Aug 5;430(7000):631-9
references: 15295589
references: J Cell Biol. 2003 Jan 20;160(2):235-43
references: 12527749
references: Nature. 2010 Apr 22;464(7292):1201-4
references: 20357768