Dysregulation of receptor interacting protein-2 and caspase recruitment domain only protein mediates aberrant caspase-1 activation in Huntington's disease.
Caspase-1 plays a role in the pathogenesis of a variety of neurological diseases. Caspase-1 activation is an early event in models of Huntington's disease (HD). However, mechanisms regulating the activation of this apical caspase in cell death are not known. Receptor interacting protein-2 (Rip2) and caspase recruitment domain (CARD) only protein (Cop) are two CARD proteins with significant homology to the caspase-1 CARD and modulate caspase-1 activation in inflammation. Rip2 is a caspase-1 activator, and Cop is a caspase-1 inhibitor. We demonstrate in models of HD that caspase-1 activation results from dysregulation of caspase-1 activation pathways. Associated with disease progression, we detect elevation of the caspase-1 activator Rip2 and reduction of the caspase-1 inhibitor Cop. Knocking down endogenous Rip2/Cop respectively results in reduced/increased sensitivity to neurotoxic stimuli. Our data provide evidence that caspase-1-mediated cell death is regulated, at least in part, by the balance of Rip2 and Cop, and alterations of this balance may contribute to aberrant caspase-1-mediated pathogenesis in Huntington's disease.
Wang
Xin
X
Department of Neurosurgery, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts 02115, USA.
Wang
Hongyan
H
Figueroa
Bryan E
BE
Zhang
Wen-Hua
WH
Huo
Chunfeng
C
Guan
Yingjun
Y
Zhang
Yu
Y
Bruey
Jean-Marie
JM
Reed
John C
JC
Friedlander
Robert M
RM
D000818:Animals; D002352:Carrier Proteins / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism; D020170:Caspase 1 / Q000235:genetics / Q000378:metabolism*; D061945:Caspase Inhibitors; D016923:Cell Death / Q000502:physiology; D002478:Cells, Cultured; D004789:Enzyme Activation / Q000502:physiology; D006367:HeLa Cells; D006801:Humans; D006816:Huntington Disease / Q000201:enzymology* / Q000235:genetics / Q000473:pathology; D051379:Mice; D009474:Neurons / Q000378:metabolism / Q000473:pathology; D017346:Protein Serine-Threonine Kinases / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000502:physiology*; D053475:Receptor-Interacting Protein Serine-Threonine Kinase 2; D053422:Receptor-Interacting Protein Serine-Threonine Kinases; D013234:Stem Cells / Q000378:metabolism / Q000473:pathology; D047988:Tumor Necrosis Factor Receptor-Associated Peptides and Proteins / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000502:physiology*
D002352:Carrier Proteins; D061945:Caspase Inhibitors; C436144:LLID-114769 protein, human; D047988:Tumor Necrosis Factor Receptor-Associated Peptides and Proteins; D017346:Protein Serine-Threonine Kinases; C506253:RIPK2 protein, human; D053475:Receptor-Interacting Protein Serine-Threonine Kinase 2; D053422:Receptor-Interacting Protein Serine-Threonine Kinases; C506255:Ripk2 protein, mouse; D020170:Caspase 1