Related Experiment Video
Updated: Jul 14, 2025
Detection of Inflammasome Activation and Pyroptotic Cell Death in Murine Bone Marrow-derived Macrophages
Published on: May 21, 2018
Muscimol inhibits plasma membrane rupture and ninjurin-1 oligomerization during pyroptosis
Andreas B den Hartigh1, Wendy P Loomis1, Marisa J Anderson1
1Department of Laboratory Medicine and Pathology, University of Washington, Seattle, WA, USA.
Abstract:
Pyroptosis is a cell death process that causes inflammation and contributes to numerous diseases. Pyroptosis is mediated by caspase-1 family proteases that cleave the pore-forming protein gasdermin D, causing plasma membrane rupture and release of pathogenic cellular contents. We previously identified muscimol as a small molecule that prevents plasma membrane rupture during pyroptosis via an unidentified mechanism. Here, we show that muscimol has reversible activity to prevent cellular lysis without affecting earlier pyroptotic events. Although muscimol is a well-characterized agonist for neuronal GABAA receptors, muscimol protection is not altered by GABAA receptor antagonists or recapitulated by other GABAA agonists, suggesting that muscimol acts via a novel mechanism. We find that muscimol blocks oligomerization of ninjurin-1, which is required for plasma membrane rupture downstream of gasdermin D pore formation. Our structure-activity relationship studies reveal distinct molecular determinants defining inhibition of pyroptotic lysis compared to GABAA binding. In addition, we demonstrate that muscimol reduces lethality during LPS-induced septic shock. Together, these findings demonstrate that ninjurin-1-mediated plasma membrane rupture can be pharmacologically modulated and pave the way toward identification of therapeutic strategies for pathologic conditions associated with pyroptosis.
Insights
Muscimol prevents cell lysis during pyroptosis, a cell death process linked to inflammation and disease. This study reveals muscimol blocks ninjurin-1 oligomerization, offering a new therapeutic target for inflammatory conditions.
Area of Science:
- Cellular biology
- Immunology
- Pharmacology
Background:
- Pyroptosis is an inflammatory cell death pathway crucial in disease, mediated by caspase-1 and gasdermin D.
- Gasdermin D cleavage causes plasma membrane rupture, releasing inflammatory cellular contents.
- Muscimol was previously identified as a molecule preventing pyroptotic cell lysis through an unknown mechanism.
Purpose of the Study:
- To elucidate the mechanism by which muscimol prevents plasma membrane rupture during pyroptosis.
- To investigate whether muscimol's effect on pyroptosis is mediated through GABAA receptors.
- To explore the therapeutic potential of muscimol in a model of septic shock.
Main Methods:
- Cell-based assays to assess pyroptosis and cell lysis.
- Pharmacological inhibition and activation of GABAA receptors.
- Structure-activity relationship studies of muscimol analogs.
- In vivo studies using LPS-induced septic shock model.
Main Results:
- Muscimol reversibly inhibited pyroptotic cell lysis without affecting upstream events.
- Muscimol's protective effect was independent of GABAA receptor activity.
- Muscimol was found to block ninjurin-1 oligomerization, a key step in membrane rupture.
- Structure-activity relationship studies identified distinct molecular determinants for pyroptosis inhibition versus GABAA binding.
- Muscimol administration reduced mortality in a mouse model of septic shock.
Conclusions:
- Muscimol inhibits pyroptotic cell lysis by blocking ninjurin-1 oligomerization, independent of GABAA receptors.
- Ninjurin-1 is a novel target for modulating pyroptosis-associated membrane rupture.
- Pharmacological targeting of ninjurin-1 offers a potential therapeutic strategy for diseases involving pyroptosis.
Related Concept Videos
01:26Directly Acting Muscle Relaxants: Dantrolene and Botulinum Toxin
The binding of dantrolene to the RYR1...
01:26Fusion of Secretory Vesicles with the Plasma Membrane
In 1993, Jim Rothman proposed that the antiparallel pairing of vesicular and transmembrane SNAREs, or...
01:29Neuromuscular Junction And Blockade
01:31The Intrinsic Apoptotic Pathway
01:28Nitric Oxide Signaling Pathway
01:15Receptor Downregulation in MVBs
The EGFR can initiate signaling pathways that lead to cell proliferation, migration, and differentiation. Overexpression of EGFR stimulates cells to proliferate. Excessive EGFR...