A Caspase Cascade Regulating Developmental Axon Degeneration

Simon, David; Weimer, Robby M.; McLaughlin, Todd; Kallop, Dara; Stanger, Karen; Yang, Jing; O’Leary, Dennis D.M.; Hannoush, Rami N.; Tessier‐Lavigne, Marc

doi:10.1523/jneurosci.3012-12.2012

Cited by 188 publications

(251 citation statements)

References 58 publications

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“…201 Caspase-3 and -6 have also been implicated in the process of axonal guidance. 202 Normal brain functions depend on proper synaptic activity. Long-term potentiation (LTP) and long-term depression (LTD) are long-lasting modifications of synapses, in the hippocampus region.…”

Section: Caspases In Neural Developmentmentioning

confidence: 99%

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Old, new and emerging functions of caspases

et al. 2014

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Caspases are proteases with a well-defined role in apoptosis. However, increasing evidence indicates multiple functions of caspases outside apoptosis. Caspase-1 and caspase-11 have roles in inflammation and mediating inflammatory cell death by pyroptosis. Similarly, caspase-8 has dual role in cell death, mediating both receptor-mediated apoptosis and in its absence, necroptosis. Caspase-8 also functions in maintenance and homeostasis of the adult T-cell population. Caspase-3 has important roles in tissue differentiation, regeneration and neural development in ways that are distinct and do not involve any apoptotic activity. Several other caspases have demonstrated anti-tumor roles. Notable among them are caspase-2, -8 and -14. However, increased caspase-2 and -8 expression in certain types of tumor has also been linked to promoting tumorigenesis. Increased levels of caspase-3 in tumor cells causes apoptosis and secretion of paracrine factors that promotes compensatory proliferation in surrounding normal tissues, tumor cell repopulation and presents a barrier for effective therapeutic strategies. Besides this caspase-2 has emerged as a unique caspase with potential roles in maintaining genomic stability, metabolism, autophagy and aging. The present review focuses on some of these less studied and emerging functions of mammalian caspases.

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Section: Caspases In Neural Developmentmentioning

confidence: 99%

“…It is again worth noting that during LTD, transient caspase-3 activation occurs without causing cell death. 202 …”

Section: Caspases In Neural Developmentmentioning

confidence: 99%

Old, new and emerging functions of caspases

et al. 2014

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“…The active cysteinal Caspase-6 protease (Casp6), associated with axonal degeneration, [9][10][11][12][13] is highly abundant in NFT, neuropil threads, and neuritic plaques of AD brains. 14 In some aged non-cognitively impaired individuals, Casp6 activity in the entorhinal cortex and CA1 regions of the hippocampus, 15 two areas initially affected by NFT pathology in AD, 16 correlates significantly with lower cognitive performance.…”

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confidence: 99%

Neuronal NLRP1 inflammasome activation of Caspase-1 coordinately regulates inflammatory interleukin-1-beta production and axonal degeneration-associated Caspase-6 activation

et al. 2015

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Neuronal active Caspase-6 (Casp6) is associated with Alzheimer disease (AD), cognitive impairment, and axonal degeneration. Caspase-1 (Casp1) can activate Casp6 but the expression and functionality of Casp1-activating inflammasomes has not been welldefined in human neurons. Here, we show that primary cultures of human CNS neurons expressed functional Nod-like receptor protein 1 (NLRP1), absent in melanoma 2, and ICE protease activating factor, but not the NLRP3, inflammasome receptor components. NLRP1 neutralizing antibodies in a cell-free system, and NLRP1 siRNAs in neurons hampered stress-induced Casp1 activation. NLRP1 and Casp1 siRNAs also abolished stress-induced Casp6 activation in neurons. The functionality of the NLRP1 inflammasome in serum-deprived neurons was also demonstrated by NLRP1 siRNA-mediated inhibition of speck formation of the apoptosis-associated speck-like protein containing a caspase recruitment domain conjugated to green fluorescent protein. These results indicated a novel stress-induced intraneuronal NLRP1/Casp1/Casp6 pathway. Lipopolysaccharide induced Casp1 and Casp6 activation in wild-type mice brain cortex, but not in that of Nlrp1 − / − and Casp1 − / − mice. NLRP1 immunopositive neurons were increased 25-to 30-fold in AD brains compared with non-AD brains. NLRP1 immunoreactivity in these neurons co-localized with Casp6 activity. Furthermore, the NLRP1/Casp1/Casp6 pathway increased amyloid beta peptide 42 ratio in serum-deprived neurons. Therefore, CNS human neurons express functional NLRP1 inflammasomes, which activate Casp1 and subsequently Casp6, thus revealing a fundamental mechanism linking intraneuronal inflammasome activation to Casp1-generated interleukin-1-β-mediated neuroinflammation and Casp6-mediated axonal degeneration.

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“…8 Casp6 activity is involved in axonal degeneration of mouse PNS neurons via amyloid precursor protein (APP) interaction with death receptor 6 9 and in nerve growth factor (NGF)-deprived dorsal root ganglion neurons. 10 Furthermore, Casp6-dependent axonal degeneration is modulated by NGF deprivation of the axonal compartment. 11 Casp6-mediated neurodegeneration also occurs in myelinand p75NTR (neurotrophin factor)-dependent axonal degeneration in adult mouse brains.…”

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confidence: 99%

Caspase-6 activity in the CA1 region of the hippocampus induces age-dependent memory impairment

et al. 2014

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Active Caspase-6 is abundant in the neuropil threads, neuritic plaques and neurofibrillary tangles of Alzheimer disease brains. However, its contribution to the pathophysiology of Alzheimer disease is unclear. Here, we show that higher levels of Caspase-6 activity in the CA1 region of aged human hippocampi correlate with lower cognitive performance. To determine whether Caspase-6 activity, in the absence of plaques and tangles, is sufficient to cause memory deficits, we generated a transgenic knock-in mouse that expresses a self-activated form of human Caspase-6 in the CA1. This Caspase-6 mouse develops agedependent spatial and episodic memory impairment. Caspase-6 induces neuronal degeneration and inflammation. We conclude that Caspase-6 activation in mouse CA1 neurons is sufficient to induce neuronal degeneration and age-dependent memory impairment. These results indicate that Caspase-6 activity in CA1 could be responsible for the lower cognitive performance of aged humans. Consequently, preventing or inhibiting Caspase-6 activity in the aged may provide an efficient novel therapeutic approach against Alzheimer disease. Cell Death and Differentiation (2014) 21, 696-706; doi:10.1038/cdd.2013; published online 10 January 2014The underlying molecular pathway for neuronal degeneration and dysfunction in Alzheimer's disease (AD) remains unknown. Yet, the identification of critical events initiating neuronal degeneration could provide a novel therapeutic approach to stem the progressive dementia of AD. We propose that Caspase-6 (Casp6), a cysteinyl protease of the caspase family, has a critical role in AD neuronal degeneration and cognitive impairment. Casp6 activity is intimately associated with the neuritic plaques (NP), neurofibrillary tangles (NFT), and neuropil threads (NPT) of AD. 1 Casp6 activity is abundant in familial AD 2 and at all stages of sporadic AD. 3 Although no Casp6 activity is present in younger brains, 1 several aged non-cognitively impaired (NCI) brains show significant amounts of Casp6 activity in the entorhinal cortex (ERC), 3 the first area showing NFT pathology in AD according to Braak staging. 4,5 Furthermore, higher levels of Casp6 activity in the ERC and cornu ammonis 1 (CA1) region of NCI brains correlate with lower episodic memory (EP) performance, one of the types of memory also affected early in AD. 6 Active Casp6 induces several parallel degenerative pathways associated with AD neuropathology. First, Casp6 activity disrupts the neuronal cytoskeleton. Casp6 cleaves neuronal microtubule protein alpha-tubulin, microtubuleassociated protein Tau, and actin-regulating post-synaptic density proteins, Spinophilin, Drebrin, and Actinins. 7 In mouse, caspase activity precedes and leads to the formation of NFT-like aggregation. 8 Casp6 activity is involved in axonal degeneration of mouse PNS neurons via amyloid precursor protein (APP) interaction with death receptor 6 9 and in nerve growth factor (NGF)-deprived dorsal root ganglion neurons. 10 Furthermore, Casp6-dependent axonal degeneration i...

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A Caspase Cascade Regulating Developmental Axon Degeneration

Cited by 188 publications

References 58 publications

Old, new and emerging functions of caspases

Old, new and emerging functions of caspases

Neuronal NLRP1 inflammasome activation of Caspase-1 coordinately regulates inflammatory interleukin-1-beta production and axonal degeneration-associated Caspase-6 activation

Caspase-6 activity in the CA1 region of the hippocampus induces age-dependent memory impairment

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