FasL‐triggered death of Jurkat cells requires caspase 8‐induced, ATP‐dependent cross‐talk between fas and the purinergic receptor P2X71. Issue 2 (25th October 2012)

• Record Type: Journal Article
• Authors: Aguirre, Adam; Shoji, Kenji F.; Sáez, Juan C.; Henríquez, Mauricio; Quest, Andrew FG
• Is Part Of: Journal of cellular physiology. Volume 228:Issue 2(2013:Feb.)
• Page Start: 485
• Page End: 493
• Publication Date: 2012-10-25
• Subjects: Physiology -- Periodicals; Cell physiology -- Periodicals; 571.6
• DOI: 10.1002/jcp.24159
• Languages: English
• ISSNs: 0021-9541

Abstract

Abstract: Fas ligation via the ligand FasL activates the caspase‐8/caspase‐3‐dependent extrinsic death pathway. In so‐called type II cells, an additional mechanism involving tBid‐mediated caspase‐9 activation is required to efficiently trigger cell death. Other pathways linking FasL–Fas interaction to activation of the intrinsic cell death pathway remain unknown. However, ATP release and subsequent activation of purinergic P2X7 receptors (P2X7 Rs) favors cell death in some cells. Here, we evaluated the possibility that ATP release downstream of caspase‐8 via pannexin1 hemichannels (Panx1 HCs) and subsequent activation of P2X7 Rs participate in FasL‐stimulated cell death. Indeed, upon FasL stimulation, ATP was released from Jurkat cells in a time‐ and caspase‐8‐dependent manner. Fas and Panx1 HCs colocalized and inhibition of the latter, but not connexin hemichannels, reduced FasL‐induced ATP release. Extracellular apyrase, which hydrolyzes ATP, reduced FasL‐induced death. Also, oxidized‐ATP or Brilliant Blue G, two P2X7 R blockers, reduced FasL‐induced caspase‐9 activation and cell death. These results represent the first evidence indicating that the two death receptors, Fas and P2X7 R connect functionally via caspase‐8 and Panx1 HC‐mediated ATP release to promote caspase‐9/caspase‐3‐dependent cell death in lymphoid cells. Thus, a hitherto unsuspected route was uncovered connecting the extrinsic to the intrinsic pathway to amplify death signals emanating from the Fas receptor in type II cells. J. Cell. Physiol. 228: 485–493, 2013. © 2012 Wiley Periodicals, Inc.