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Activation of RKIP Binding ASC Attenuates Neuronal Pyroptosis and Brain Injury via Caspase-1/GSDMD Signaling Pathway
Lingui Gu1, Mingjiang Sun1, Ruihao Li1
1Department of Neurosurgery, The Second Affiliated Hospital, Chongqing Medical University, 76 Linjiang Road, Chongqing, 400010, China.
Abstract:
Pyroptosis has been proven to be responsible for secondary brain injury after intracerebral hemorrhage (ICH). A recent study reported that Raf kinase inhibitor protein (RKIP) inhibited assembly and activation of inflammasome in macrophages. Our present study aimed to investigate the effects of RKIP on inflammasome-mediated neuronal pyroptosis and underlying neuroprotective mechanisms in experimental ICH. Here, we showed that RKIP expression was decreased both in cerebrospinal fluid (CSF) samples from patients with ICH and in the peri-hematoma tissues after experimental ICH. In mouse ICH model, activation of RKIP remarkably improved neurological deficits, reduced brain water content and BBB disruption, and promoted hematoma absorption at 24 h after ICH, as well as alleviated neuronal degeneration, reduced membrane pore formation, and downregulated pyroptotic molecules NLRP3, caspase-1 P20, GSDMD-N, and mature IL-1β. Besides, RKIP activation decreased the number of caspase-1 P20-positive neurons after ICH. However, RKIP inhibitor reserved the neuroprotective effects of RKIP at 24 h following ICH. Moreover, RKIP could bind with ASC, then interrupt the assembly of NLRP3 inflammasome. Mechanistically, inhibiting the caspase-1 by VX-765 attenuated brain injury and suppressed neuronal pyroptosis after RKIP inhibitor-pretreated ICH. In conclusion, our findings indicated that activation of RKIP could attenuate neuronal pyroptosis and brain injury after ICH, to some extent, through ASC/Caspase-1/GSDMD pathway. Thus, RKIP may be a potential target to attenuate brain injury via its anti-pyroptosis effect after ICH.
Insights
Raf kinase inhibitor protein (RKIP) activation reduces brain injury after intracerebral hemorrhage (ICH) by inhibiting pyroptosis. RKIP may be a potential therapeutic target for ICH treatment.
Area of Science:
- Neuroscience
- Cell Biology
- Biochemistry
Background:
- Pyroptosis contributes to secondary brain injury following intracerebral hemorrhage (ICH).
- Raf kinase inhibitor protein (RKIP) has been shown to inhibit inflammasome assembly and activation in macrophages.
Purpose of the Study:
- To investigate the effects of RKIP on inflammasome-mediated neuronal pyroptosis in experimental ICH.
- To elucidate the underlying neuroprotective mechanisms of RKIP in ICH.
Main Methods:
- Assessed RKIP expression in CSF from ICH patients and peri-hematoma tissues.
- Utilized a mouse ICH model to evaluate RKIP activation effects on neurological deficits, brain water content, BBB disruption, and hematoma absorption.
- Analyzed neuronal degeneration, membrane pore formation, and pyroptotic molecules (NLRP3, caspase-1, GSDMD-N, IL-1β).
- Investigated RKIP's interaction with ASC and its effect on NLRP3 inflammasome assembly.
- Examined the impact of caspase-1 inhibition (VX-765) on brain injury and pyroptosis.
Main Results:
- RKIP expression was decreased in ICH patients and experimental ICH models.
- RKIP activation improved neurological deficits, reduced brain edema and BBB disruption, and promoted hematoma absorption in mice.
- RKIP activation alleviated neuronal degeneration, reduced membrane pore formation, and downregulated pyroptotic markers.
- RKIP directly binds to ASC, inhibiting NLRP3 inflammasome assembly.
- Inhibition of caspase-1 attenuated brain injury and pyroptosis in RKIP inhibitor-pretreated ICH models.
Conclusions:
- RKIP activation attenuates neuronal pyroptosis and brain injury after ICH.
- RKIP exerts its neuroprotective effects by targeting the ASC/Caspase-1/GSDMD pathway.
- RKIP represents a potential therapeutic target for mitigating brain injury through its anti-pyroptosis effects in ICH.
