Pyroptotic Neuronal Cell Death Mediated by the AIM2 Inflammasome

• Published in: Journal of cerebral blood flow and metabolism Vol. 34; no. 4; pp. 621 - 629
• Main Authors: Adamczak, Stephanie E, de Rivero Vaccari, Juan Pablo, Dale, Gordon, Brand, Frank J, Nonner, Doris, Bullock, MRoss, Dahl, Gerhard P, Dietrich, W Dalton, Keane, Robert W
• Format: Journal Article
• Language: English
• Published: London, England SAGE Publications 01.04.2014; Sage Publications Ltd; Nature Publishing Group
• Subjects: Adolescent; Adult; Aged; Animals; Apoptosis - drug effects; Apoptosis - immunology; Apoptosis Regulatory Proteins - metabolism; Brain Injuries - cerebrospinal fluid; Brain Injuries - immunology; Brain Injuries - metabolism; Brain Injuries - pathology; Caspase 1 - metabolism; Cell Culture Techniques; Cell Death; Cells, Cultured; Cerebral Cortex - cytology; Cerebral Cortex - embryology; DNA-Binding Proteins; Female; Humans; Immunity, Innate - drug effects; Inflammasomes - immunology; Inflammasomes - metabolism; Male; Middle Aged; Neurons - drug effects; Neurons - immunology; Neurons - metabolism; Neurons - pathology; Nuclear Proteins - metabolism; Original; Poly dA-dT - pharmacology; Probenecid - pharmacology; Rats; Rats, Sprague-Dawley; Young Adult; cell death; innate immunity; inflammasomes; brain trauma; cerebrospinal fluid
• ISSN: 0271-678X; 1559-7016
• DOI: 10.1038/jcbfm.2013.236

The central nervous system (CNS) is an active participant in the innate immune response to infection and injury. In these studies, we show embryonic cortical neurons express a functional, deoxyribonucleic acid (DNA)-responsive, absent in melanoma 2 (AIM2) inflammasome that activates caspase-1. Neurons undergo pyroptosis, a proinflammatory cell death mechanism characterized by the following: (a) oligomerization of apoptosis-associated speck-like protein containing a caspase recruitment domain (ASC); (b) caspase-1 dependency; (c) formation of discrete pores in the plasma membrane; and (d) release of the inflammatory cytokine interleukin-1β (IL-1β). Probenecid and Brilliant Blue FCF, inhibitors of the pannexin1 channel, prevent AIM2 inflammasome-mediated cell death, identifying pannexin1 as a cell death effector during pyroptosis and probenecid as a novel pyroptosis inhibitor. Furthermore, we show activation of the AIM2 inflammasome in neurons by cerebrospinal fluid (CSF) from traumatic brain injury (TBI) patients and oligomerization of ASC. These findings suggest neuronal pyroptosis is an important cell death mechanism during CNS infection and injury that may be attenuated by probenecid.