Researchers from Virginia Commonwealth University have synthesized and investigated a new inhibitor molecule, designated YM81, targeting gasdermin D (GSDMD), a pivotal protein implicated in pyroptosis — an inflammatory form of programmed cell death strongly associated with acetaminophen-induced liver injury (AILI). Pyroptosis facilitates the release of pro-inflammatory cytokines, amplifying liver damage. By inhibiting GSDMD, YM81 attenuates pyroptosis, thereby reducing inflammation and preserving liver function in affected models.

Presented at the 2025 American Chemical Society (ACS) fall meeting, which unites thousands of scientists from varying disciplines, the study was led by graduate student Jannatun Nayem Namme alongside principal investigator Dr. Shijun Zhang. The research highlights the therapeutic potential of targeting inflammasome-related proteins, particularly in illnesses where inflammation exacerbates tissue destruction. This approach could signify a shift in therapeutic strategies beyond acetaminophen toxicity to broader inflammatory and neurodegenerative disorders.

The pathology of acetaminophen overdose begins with the liver’s metabolic conversion of the drug to NAPQI. Under normal consumption, detoxification mechanisms swiftly neutralize NAPQI, preventing cellular harm. In overdose scenarios, the accumulation of NAPQI surpasses detoxification capacity, triggering oxidative stress, mitochondrial dysfunction, and ultimately necrosis of hepatocytes. Notably, inflammasomes like NLRP3 and effector proteins such as GSDMD have shown integral roles in mediating the inflammatory response and cell death via pyroptosis during this injury.

Prior to YM81’s development, the pharmacologic armamentarium included only N-acetylcysteine, which replenishes glutathione to detoxify NAPQI but is only effective within an eight-hour window post-overdose. This narrow therapeutic window underscores the urgent need for additional treatments that can either extend this timeframe or directly halt the inflammatory processes causing liver damage.

YM81’s mechanism centers on its interaction with GSDMD. Usually, GSDMD is cleaved by activated caspase-1, releasing its N-terminal fragment that oligomerizes and inserts into cell membranes to form pores. These pores enable the secretion of interleukin-1β (IL-1β) and interleukin-18 (IL-18), cytokines that magnify immune responses and perpetuate pyroptotic cell death. By binding selectively and potently to GSDMD, YM81 inhibits pore formation, reducing cytokine release and preserving hepatocyte integrity.

In mouse models of AILI, treatment with YM81 yielded remarkable reductions in serum biomarkers indicative of liver injury, specifically alanine aminotransferase (ALT) and aspartate aminotransferase (AST). These enzymes, when elevated, reflect hepatocyte damage and necrosis. Compared to placebo-treated controls, YM81-treated mice demonstrated significantly diminished hepatic inflammation and cellular death 17 hours post-overdose, underscoring the molecule’s efficacy in mitigating pathological cascades initiated by acetaminophen toxicity.

Additionally, biochemical assays revealed that YM81 demonstrates nanomolar affinity for GSDMD, with an equilibrium dissociation constant (KD) of approximately 197 nM, reflecting tight binding and potent inhibition. In macrophage cultures stimulated to induce inflammasome activation, YM81 dose-dependently inhibited cleavage of GSDMD and caspase-1, reaffirming its mechanism in suppressing pyroptosis.

The therapeutic implications of YM81 extend beyond AILI. GSDMD is increasingly recognized as a central mediator in various inflammatory and neurodegenerative diseases, including arthritis, sepsis, and gout. By impeding GSDMD activation, YM81 or optimized derivatives could potentially modulate excessive inflammatory responses in multiple pathological contexts where pyroptosis exacerbates tissue injury.

Current efforts by Dr. Zhang’s team emphasize optimizing YM81’s pharmacological characteristics, with the aims of enhancing its potency, improving safety profiles, and increasing molecular stability to ensure viability as a therapeutic agent. Furthermore, expanded studies in diverse animal models are being pursued to validate the compound’s efficacy across conditions characterized by inflammation-driven damage.

This innovative work, partially funded by the National Institute on Aging, represents a promising stride in drug development targeting inflammasomes and related signaling pathways. By elucidating the molecular underpinnings of pyroptosis and its regulation, such research paves the way for novel interventions capable of mitigating the burden of acute liver injury and inflammatory disorders at large.

The ACS Fall 2025 meeting serves as an important platform for disseminating such scientific advances. With over 9,000 presentations spanning multiple domains of chemistry and related sciences, the conference fosters collaborative efforts that accelerate translational innovations from bench to bedside.

In summary, the discovery of YM81 sets the stage for a new class of therapeutics aimed at modulating the inflammasome-gasdermin axis. It embodies the potential to revolutionize treatment paradigms for acetaminophen toxicity and various inflammatory diseases by directly intervening in the cellular death pathways that underlie these conditions.

Subject of Research: Development of a novel GSDMD inhibitor targeting acetaminophen-induced liver injury

Article Title: Development of a novel GSDMD inhibitor for the treatment of acetaminophen-induced liver injury

News Publication Date: August 18, 2025

Web References: ACS Fall 2025 program presentation

Keywords: Acetaminophen overdose, acute liver injury, pyroptosis, gasdermin D, inflammasomes, novel inhibitors, YM81, inflammatory diseases, drug development, N-acetyl-p-benzoquinone imine, NLRP3, caspase-1, cytokines

Gouty arthritis, a widespread inflammatory disease characterized by severe joint pain and swelling, has long posed a challenge to clinicians due to its complex etiology and limited effective treatment options. At the core of its pathology lies the uncontrolled inflammation triggered by monosodium urate crystal deposition in joints, which activates innate immune responses. However, the precise molecular cascades orchestrating these inflammatory responses are still being elucidated, making studies like this one critically important.

The recent investigation centers on NEDD4, an E3 ubiquitin ligase that plays a pivotal role in protein degradation and cellular signaling pathways. Researchers found that NEDD4 undergoes a specific chemical modification known as S-nitrosylation at the cysteine residue 365 (C365). This modification critically alters NEDD4’s function, inhibiting its ability to tag its substrate NOD1 — a pattern recognition receptor — for ubiquitination and subsequent degradation. As a result, NOD1 accumulates within the cell, driving inflammatory cascades that fuel GA’s progression.

NOD1, traditionally recognized for its role in detecting bacterial components and mediating innate immune responses, emerges from this study as a crucial regulator of pyroptosis — a highly inflammatory form of programmed cell death distinct from apoptosis and necrosis. Through its activation, NOD1 instigates the assembly of molecular complexes including NLRP3, ASC, and caspase-1, all instrumental in cleaving gasdermin D to its active GSDMD-N form, which perforates the plasma membrane and facilitates the release of pro-inflammatory cytokines such as interleukin-1β (IL-1β) and interleukin-18 (IL-18).

By employing both in vivo mouse models of GA and sophisticated in vitro cellular systems, the researchers demonstrated that knocking down NOD1 led to marked reductions in pyroptotic markers and inflammatory cytokines. This intervention also alleviated histopathological joint damage and decreased xanthine oxidase (XOD) activity, a key enzyme involved in uric acid synthesis and gout pathology. These findings decisively position NOD1 as a linchpin in GA-induced pyroptosis and inflammation.

Delving deeper, the team unraveled the upstream regulatory events that modulate NOD1 expression. They identified that inducible nitric oxide synthase (iNOS) facilitates NEDD4 S-nitrosylation, thereby impairing NEDD4’s ubiquitin ligase activity toward NOD1. This intricate regulatory axis underscores a feedback loop where iNOS not only drives the inflammatory milieu via nitric oxide production but also indirectly stabilizes pro-inflammatory mediators by altering ubiquitination pathways.

The implications of these findings are profound, as they illuminate novel molecular targets for therapeutic intervention in GA. Specifically, strategies aimed at preventing NEDD4 S-nitrosylation or enhancing NOD1 degradation could attenuate pyroptosis-driven inflammation, offering relief to millions of patients worldwide suffering from this chronic disease. Importantly, the study pioneers in establishing the expression profiles of both NEDD4 and NOD1 in GA, filling a critical knowledge gap in gout research.

This study’s revelation that S-nitrosylation, a reversible yet impactful post-translational modification, can modulate ubiquitin ligase activity adds a new layer of complexity to our understanding of protein regulation under inflammatory stress. It highlights the delicate balance cells maintain in controlling protein stability and immune responses, emphasizing how dysregulation at this level can ignite pathological inflammation.

Moreover, by connecting NOD1 to the activation of the NLRP3 inflammasome pathway, the research integrates several previously disparate molecular threads in GA pathophysiology. The NLRP3 inflammasome has been extensively studied for its role in sensing danger signals and coordinating immune responses, yet the mechanisms controlling its upstream activation have remained somewhat elusive. Here, the stabilization of NOD1 emerges as a crucial upstream event, providing new mechanistic insights.

Clinically, these findings suggest that biomarkers reflecting NEDD4 S-nitrosylation status or NOD1 abundance could serve as diagnostic indicators of GA severity or therapeutic response. Furthermore, pharmacological agents capable of modulating iNOS activity or interfering with the S-nitrosylation process hold promise as novel therapeutic candidates.

Further exploration into the signaling interplay between nitric oxide signaling, ubiquitin-proteasome pathways, and inflammasome activation promises to unravel additional layers of immune regulation pertinent not only to gout but potentially other inflammatory diseases as well. The study’s robust experimental design, spanning molecular biology, immunology, and animal modeling, lends significant weight to its conclusions.

Importantly, this research signifies a paradigm shift in how we conceptualize gout’s inflammatory mechanisms, moving beyond uric acid crystallization alone toward a more integrated view involving post-translational modifications and programmed cellular demise. This broader framework may ultimately revolutionize treatment strategies and improve patient outcomes.

As the prevalence of gout continues to rise globally, driven by aging populations and lifestyle factors, harnessing insights from studies like this will be pivotal in addressing unmet clinical needs. The capacity to target molecular switches such as NEDD4 S-nitrosylation could herald the arrival of precision medicine approaches tailored to interrupt pathological inflammation at its source.

In summary, the elucidation of S-nitrosylated NEDD4’s role in stabilizing NOD1 and consequently triggering NLRP3-dependent pyroptosis represents a significant advance in the understanding of gouty arthritis pathogenesis. This research not only contributes foundational knowledge but also charts a clear course toward innovative therapeutic interventions aimed at mitigating disease progression by modulating protein post-translational modifications and innate immune signaling.

The insights gained from this work are anticipated to galvanize further studies exploring the molecular intricacies of pyroptosis and ubiquitination in inflammatory diseases. Ultimately, leveraging the mechanistic revelations surrounding NEDD4 and NOD1 may transform the therapeutic landscape for gout and potentially other inflammasome-related disorders, offering hope for improved care and quality of life for affected individuals worldwide.

Subject of Research: Molecular mechanisms underlying gouty arthritis progression through regulation of pyroptosis by S-nitrosylated NEDD4 and NOD1 signaling.

Article Title: S-nitrosylated NEDD4 exacerbates gouty arthritis by upregulating NOD1 to induce pyroptosis.

Article References:
Qu, X., Wang, Q. & Qiu, H. S-nitrosylated NEDD4 exacerbates gouty arthritis by upregulating NOD1 to induce pyroptosis. Genes Immun (2025). https://doi.org/10.1038/s41435-025-00341-7

Image Credits: AI Generated

DOI: https://doi.org/10.1038/s41435-025-00341-7