Activation of CPP32 during apoptosis of neurons and astrocytes

Keane, Robert W.; Srinivasan, Anu; Foster, Lyndon M.; Testa, Maria Pia; Örd, Tönis; Nonner, Doris; Wang, Hong Gang; Reed, John C.; Bredesen, Dale E.; Kayalar, Celik

doi:10.1002/(sici)1097-4547(19970415)48:2<168::aid-jnr9>3.0.co;2-a

Cited by 144 publications

(90 citation statements)

References 47 publications

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“…The medium was removed and replaced with medium containing probenecid and 130 mM KCl for 30 min, 1 h, and 2 h, whereas controls received probenecid alone. Cells were washed once in ice-cold PBS and lysed as described previously (25) and prepared for immunoblot analysis.…”

Section: Methodsmentioning

confidence: 99%

The Pannexin 1 Channel Activates the Inflammasome in Neurons and Astrocytes

Silverman¹,

Vaccari

Locovei³

et al. 2009

Journal of Biological Chemistry

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490

603

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The inflammasome is a multiprotein complex involved in innate immunity. Activation of the inflammasome causes the processing and release of the cytokines interleukins 1␤ and 18. In primary macrophages, potassium ion flux and the membrane channel pannexin 1 have been suggested to play roles in inflammasome activation. However, the molecular mechanism(s) governing inflammasome signaling remains poorly defined, and it is undetermined whether these mechanisms apply to the central nervous system. Here we show that high extracellular potassium opens pannexin channels leading to caspase-1 activation in primary neurons and astrocytes. The effect of K ؉ on pannexin 1 channels was independent of membrane potential, suggesting that stimulation of inflammasome signaling was mediated by an allosteric effect. The activation of the inflammasome by K Pannexin 1 is a vertebrate ortholog of the invertebrate innexin gap junction proteins (1), but it does not appear to form functional gap junctions in vivo. Instead pannexin 1 acts as a membrane channel that carries ions and signaling molecules between the cytoplasm and the extracellular space (2, 3). As such, it is a candidate ATP release channel in various cell types, including erythrocytes, astrocytes, bronchial epithelial cells, and taste cells. Various functional roles have been ascribed to pannexin 1 including local vascular perfusion control and propagation of intercellular calcium waves (4 -6). Recently pannexin 1 was also shown to form the large pore of the P2X7 purinergic receptor (7, 8). P2X7 plays a major role in inflammation, and its activation by extracellular ATP results in release of interleukin (IL) 2 -1␤ from macrophages, probably involving pannexin 1 as a signaling molecule (7).IL-1␤ production and maturation are tightly regulated by caspase-1 incorporated into large protein complexes termed inflammasomes (9 -11). The molecular composition of the inflammasome depends on the identity of the NOD-like receptor (NLR) family member serving as a scaffold protein in the complex (12). The members of the cytosolic NLR family appear to recognize conserved microbial and viral components termed pathogen-associated molecular patterns in intracellular compartments (13). The bipartite adaptor protein apoptosis-associated speck-like protein containing a CARD (ASC) bridges the interaction between NLR proteins and inflammatory caspases and plays a central role in the assembly of inflammasomes and the activation of caspase-1 in response to a broad range of pathogen-associated molecular patterns and intracellular pathogens (14). In addition, the inflammasome can be activated by danger-associated molecular patterns, molecules endogenous to the organism that signal stress or injury, including extracellular ATP acting at ionotropic P2X7 receptors, fibronectin, or monosodium urate crystals (15,16). Moreover it has been suggested that a rapid K ϩ efflux through ATP-activated P2X7 receptors induces inflammasome assembly (17)(18)(19)(20).Despite the recent advances in the understanding of a...

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Section: Methodsmentioning

confidence: 99%

The Pannexin 1 Channel Activates the Inflammasome in Neurons and Astrocytes

Silverman¹,

Vaccari

Locovei³

et al. 2009

Journal of Biological Chemistry

Self Cite

490

603

View full text Add to dashboard Cite

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“…Immunoprecipitates or equal amounts of protein in lysates were resolved on 8.5% SDS-PAGE, transferred to polyvinylidene fluoride membranes, and placed in blocking buffer (0.1% Tween 20, 0.4% I-block in PBS; Applied Biosystems) for 1 hr (Keane et al, 1997). Membranes were then incubated with primary antibodies followed by the appropriate secondary antibody.…”

Section: Methodsmentioning

confidence: 99%

Tumor Necrosis Factor Receptor 1 and Its Signaling Intermediates Are Recruited to Lipid Rafts in the Traumatized Brain

Lotocki¹,

Alonso

Dietrich³

et al. 2004

J. Neurosci.

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The tumor necrosis factor (TNF) ligand-receptor system plays an essential role in apoptosis that contributes to secondary damage after traumatic brain injury (TBI). TNF also stimulates inflammation by activation of gene transcription through the IB kinase (IKK)/NF-B and JNK (c-Jun N-terminal protein kinase)/AP-1 signaling cascades. The mechanism by which TNF signals between cell death and survival and the role of receptor localization in the activation of downstream signaling events are not fully understood. Here, TNF receptor 1 (TNFR1) signaling complexes in lipid rafts were investigated in the cerebral cortex of adult male Sprague Dawley rats subjected to moderate (1.8 -2.2 atmospheres) fluid-percussion TBI and naive controls. In the normal rat cortex, a portion of TNFR1 was present in lipid raft microdomains, where it associated with the adaptor proteins TRADD (TNF receptor-associated death domain), TNF receptorassociated factor-2 (TRAF-2), the Ser/Thr kinase RIP (receptor-interacting protein), TRAF1, and cIAP-1 (cellular inhibitor of apoptosis protein-1), forming a survival signaling complex. Moderate TBI resulted in rapid recruitment of TNFR1, but not TNFR2 or Fas, to lipid rafts and induced alterations in the composition of signaling intermediates. TNFR1 and TRAF1 were polyubiquitinated in lipid rafts after TBI. Subsequently, the signaling complex contained activated caspase-8, thus initiating apoptosis. In addition, TBI caused a transient activation of NF-B, but receptor signaling interacting proteins IKK␣ and IKK␤ were not detected in raft-containing fractions. Thus, redistribution of TNFR1 in lipid rafts and nonraft regions of the plasma membrane may regulate the diversity of signaling responses initiated by these receptors in the normal brain and after TBI.

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“…Triplicate cultures of BEAS-2B and SAEC cells were prepared in 96 well plates for analysis of viability using the Alamar Blue bioassay (Invitrogen, Carlsbad, CA), following procedures described previously [44]. Parallel cultures were also prepared in duplicate in 1 mL chamber slides for the analysis of apoptosis using the TUNEL assay following the manufacturer's directions (Roche, Inc., Indianapolis, IN) with some modifications outlined previously [45].…”

Section: Viability and Apoptosismentioning

confidence: 99%

Single-walled carbon nanotube-induced mitotic disruption

Sargent

Hubbs

Young

et al. 2012

Mutation Research/Genetic Toxicology and Environmental Mutagene

148

123

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Carbon nanotubes were among the earliest products of nanotechnology and have many potential applications in medicine, electronics, and manufacturing. The low density, small size, and biological persistence of carbon nanotubes create challenges for exposure control and monitoring and make respiratory exposures to workers likely. We have previously shown mitotic spindle aberrations in cultured primary and immortalized human airway epithelial cells exposed to 24, 48 and 96 μg/cm 2 single-walled carbon nanotubes (SWCNT). To investigate mitotic spindle aberrations at concentrations anticipated in exposed workers, primary and immortalized human airway epithelial cells were exposed to SWCNT for 24-72 h at doses equivalent to 20 weeks of exposure at the Permissible Exposure Limit for particulates not otherwise regulated. We have now demonstrated fragmented centrosomes, disrupted mitotic spindles and aneuploid chromosome number at those doses. The data further demonstrated multipolar mitotic spindles comprised 95% of the disrupted mitoses. The increased multipolar mitotic spindles were associated with an increased number of cells in the G2 phase of mitosis, indicating a mitotic checkpoint response. Nanotubes were observed in association with mitotic spindle microtubules, the centrosomes and condensed chromatin in cells exposed to 0.024, 0.24, 2.4 and 24 μg/cm 2 SWCNT. Three- Conflict of interest statementThe authors declare that there are no conflicts of interest. Appendix A. Supplementary dataSupplementary data associated with this article can be found, in the online version, at doi:10.1016/j.mrgentox.2011.11.017. HHS Public Access Author Manuscript Author ManuscriptAuthor ManuscriptAuthor Manuscript dimensional reconstructions showed carbon nanotubes within the centrosome structure. The lower doses did not cause cytotoxicity or reduction in colony formation after 24 h; however, after three days, significant cytotoxicity was observed in the SWCNT-exposed cells. Colony formation assays showed an increased proliferation seven days after exposure. Our results show significant disruption of the mitotic spindle by SWCNT at occupationally relevant doses. The increased proliferation that was observed in carbon nanotube-exposed cells indicates a greater potential to pass the genetic damage to daughter cells. Disruption of the centrosome is common in many solid tumors including lung cancer. The resulting aneuploidy is an early event in the progression of many cancers, suggesting that it may play a role in both tumorigenesis and tumor progression. These results suggest caution should be used in the handling and processing of carbon nanotubes.

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Activation of CPP32 during apoptosis of neurons and astrocytes

Cited by 144 publications

References 47 publications

The Pannexin 1 Channel Activates the Inflammasome in Neurons and Astrocytes

The Pannexin 1 Channel Activates the Inflammasome in Neurons and Astrocytes

Tumor Necrosis Factor Receptor 1 and Its Signaling Intermediates Are Recruited to Lipid Rafts in the Traumatized Brain

Single-walled carbon nanotube-induced mitotic disruption

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