CARD8 is an inflammasome sensor for HIV-1 protease activity

Wang, Qiankun; Gao, Hongbo; Clark, Kolin M.; Mugisha, Christian Shema; Davis, Keanu; Tang, Jack Pengfei; Harlan, Gray H.; DeSelm, Carl J.; Presti, Rachel; Kutluay, Sebla B.; Shan, Liang

doi:10.1126/science.abe1707

Cited by 109 publications

(146 citation statements)

References 45 publications

(43 reference statements)

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“…1,3 ). This unique mechanism involving 'functional degradation' is conserved in the activation of human NLRP1 (hNLRP1) by the 3C proteases of enteroviruses 14 and in the activation of CARD8 by HIV-1 protease 15 .…”

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confidence: 99%

Structural and biochemical mechanisms of NLRP1 inhibition by DPP9

Huang

Zhang

Toh

et al. 2021

Nature

112

108

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Nucleotide-binding domain, leucine-rich repeat receptors (NLRs) mediate innate immunity by forming inflammasomes. Activation of the NLR protein NLRP1 requires autocleavage within its function-to-find domain (FIIND)1–7. In resting cells, the dipeptidyl peptidases DPP8 and DPP9 interact with the FIIND of NLRP1 and suppress spontaneous NLRP1 activation8,9; however, the mechanisms through which this occurs remain unknown. Here we present structural and biochemical evidence that full-length rat NLRP1 (rNLRP1) and rat DPP9 (rDPP9) form a 2:1 complex that contains an autoinhibited rNLRP1 molecule and an active UPA–CARD fragment of rNLRP1. The ZU5 domain is required not only for autoinhibition of rNLRP1 but also for assembly of the 2:1 complex. Formation of the complex prevents UPA-mediated higher-order oligomerization of UPA–CARD fragments and strengthens ZU5-mediated NLRP1 autoinhibition. Structure-guided biochemical and functional assays show that both NLRP1 binding and enzymatic activity are required for DPP9 to suppress NLRP1 in human cells. Together, our data reveal the mechanism of DPP9-mediated inhibition of NLRP1 and shed light on the activation of the NLRP1 inflammasome.

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confidence: 99%

Structural and biochemical mechanisms of NLRP1 inhibition by DPP9

Huang

Zhang

Toh

et al. 2021

Nature

112

108

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“…First, for this mechanism to work, a cell has to express HIV Gag-Pol, and cells that express HIV proteins without ex vivo stimulation are exceedingly rare in ART-treated individuals [62]. Second, nevirapine, in comparison with other NNRTIs, has no such activity [58,59,61], but in our study, nevirapine was associated with the same levels of CA RNA as efavirenz and another study showed even lower levels of residual plasma viremia in nevirapine-treated compared to efavirenz-treated individuals [63]. This argues against induction of apoptosis of infected cells being a plausible mechanism behind the more pronounced virological suppression by NNRTIs.…”

Section: Discussionmentioning

confidence: 99%

Non-nucleoside reverse transcriptase inhibitor-based combination antiretroviral therapy is associated with lower cell-associated HIV RNA and DNA levels compared to protease inhibitor-based therapy

Pasternak¹,

Vroom²,

Kootstra³

et al. 2021

eLife

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BACKGROUND: It remains unclear whether combination antiretroviral therapy (ART) regimens differ in their ability to fully suppress HIV replication. Here, we report the results of two cross-sectional studies that compared levels of cell-associated (CA) HIV markers between individuals receiving suppressive ART containing either a non-nucleoside reverse transcriptase inhibitor (NNRTI) or a protease inhibitor (PI).METHODS: CA HIV unspliced RNA and total HIV DNA were quantified in two cohorts (n=100, n=124) of individuals treated with triple ART regimens consisting of two nucleoside reverse transcriptase inhibitors (NRTIs) plus either a NNRTI or a PI. To compare CA HIV RNA and DNA levels between the regimens, we built multivariable models adjusting for age, gender, current and nadir CD4+ count, plasma viral load zenith, duration of virological suppression, NRTI backbone composition, low-level plasma HIV RNA detectability, and electronically-measured adherence to ART.RESULTS: In both cohorts, levels of CA HIV RNA and DNA strongly correlated (rho=0.70 and rho=0.54) and both markers were lower in NNRTI-treated than in PI-treated individuals. In the multivariable analysis, CA RNA in both cohorts remained significantly reduced in NNRTI-treated individuals (padj=0.02 in both cohorts), with a similar but weaker association between the ART regimen and total HIV DNA (padj=0.048 and padj=0.10). No differences in CA HIV RNA or DNA levels were observed between individual NNRTIs or individual PIs, but CA HIV RNA was lower in individuals treated with either nevirapine or efavirenz, compared to PI-treated individuals.CONCLUSIONS: All current classes of antiretroviral drugs only prevent infection of new cells but do not inhibit HIV RNA transcription in long-lived reservoir cells. Therefore, these differences in CA HIV RNA and DNA levels by treatment regimen suggest that NNRTIs are more potent in suppressing HIV residual replication than PIs, which may result in a smaller viral reservoir size.

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“…This strategy utilizes latency reversal agents (LRAs) to reactivate the latent reservoir (shock) and then induce targeted cell death of infected cells (kill) 7 . Optimal efficiency is needed for both steps of this strategy, but we recently reported that the inflammasome sensor caspase recruitment domain 8 (CARD8) is able to sense intracellular HIV-1 protease activity and induce targeted cell killing of HIV-1 infected cells 8 .…”

Section: Introductionmentioning

confidence: 99%

“…Recent studies demonstrated that one such PRR, CARD8, triggered the CASP1 activation and pyroptosis in human CD4 + T cells when cells were treated with the known Dipeptidyl Peptidase 9 (DPP9) inhibitor Val-boroPro (VbP) 11,12 . More recently, CARD8 was shown to sense intracellular HIV-1 protease activity 8 . CARD8 C-terminus (CARD8C) contains two key domains: the function-to-find domain (FIIND) and a CARD domain.…”

Section: Introductionmentioning

confidence: 99%

“…This is due to the critical need for the virus to maintain its enzymatic activities. Several reports have shown that NNRTIs, such as Efavirenz (EFV) and Rilpivirine (RPV), can induce HIV-1 protease-dependent killing of infected CD4 + T cells 8,20,21 , which is due to activation of the CARD8 inflammasome 8 . It is clear that NNRTIs at micromolar concentrations drive Gag-Pol dimerization and intracellular protease activation which cleaves CARD8 leading to pyroptosis of HIV-1 infected cells.…”

Section: Introductionmentioning

confidence: 99%

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CARD8 inflammasome sensitization through DPP9 inhibition enhances NNRTI-triggered killing of HIV-1-infected cells

Clark

Wang

Shan

2021

Preprint

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Non-nucleoside reverse transcriptase inhibitors (NNRTIs) induce pyroptosis of HIV-1 infected CD4+ T cells through induction of intracellular viral protease activation, which then activates the CARD8 inflammasome. Due to high concentrations of NNRTIs being required for efficient CARD8 activation and elimination of HIV-1-infected cells, it is important to elucidate ways to sensitize the CARD8 inflammasome to NNRTI-induced activation. We show that this sensitization can be done through chemical inhibition of the CARD8 negative regulator DPP9. DPP9 inhibitor Val-boroPro (VbP) can act synergistically with NNRTIs to increase their efficacy in killing HIV-1-infected cells. We also show that VbP is able to partially overcome issues with NNRTI resistance and is capable of killing infected cells without the presence of NNRTIs. This offers a promising strategy for enhancing NNRTI efficacy in elimination of HIV-1 reservoirs in patients.

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CARD8 is an inflammasome sensor for HIV-1 protease activity

Cited by 109 publications

References 45 publications

Structural and biochemical mechanisms of NLRP1 inhibition by DPP9

Structural and biochemical mechanisms of NLRP1 inhibition by DPP9

Non-nucleoside reverse transcriptase inhibitor-based combination antiretroviral therapy is associated with lower cell-associated HIV RNA and DNA levels compared to protease inhibitor-based therapy

CARD8 inflammasome sensitization through DPP9 inhibition enhances NNRTI-triggered killing of HIV-1-infected cells

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