Gilad Doitsh, Nicole L. K. Galloway, Xin Geng, Zhiyuan Yang, Kathryn M. Monroe, Orlando Zepeda, Peter W. Hunt, Hiroyu Hatano, Stefanie Sowinski, Isa Muñoz-Arias & Warner C. Greene
Abstract:
The pathway causing CD4 T-cell death in HIV-infected hosts remains poorly understood although apoptosis has been proposed as a key mechanism. We now show that caspase-3-mediated apoptosis accounts for the death of only a small fraction of CD4 T cells corresponding to those that are both activated and productively infected. The remaining over 95% of quiescent lymphoid CD4 T cells die by caspase-1-mediated pyroptosis triggered by abortive viral infection. Pyroptosis corresponds to an intensely inflammatory form of programmed cell death in which cytoplasmic contents and pro-inflammatory cytokines, including IL-1β, are released. This death pathway thus links the two signature events in HIV infection—CD4 T-cell depletion and chronic inflammation—and creates a pathogenic vicious cycle in which dying CD4 T cells release inflammatory signals that attract more cells to die. This cycle can be broken by caspase 1 inhibitors shown to be safe in humans, raising the possibility of a new class of ‘anti-AIDS’ therapeutics targeting the host rather than the virus.
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Keywords:pyroptosis,CD4,T-cells,HIV-1 \,caspase-1
