Aging is accompanied by progressive structural and functional deterioration in various organs, leading to increased susceptibility to chronic diseases and reduced physiological resilience. Among these age-related changes, chronic, low-grade systemic inflammation—commonly termed “inflammaging”—has emerged as a major contributor to the onset and progression of aging-associated pathologies [1]. The liver, a central organ in metabolism, detoxification, and immune regulation, is particularly vulnerable to age-driven inflammatory and oxidative insults. Accumulating evidence suggests that age-related hepatic inflammation accelerates fibrosis, metabolic dysregulation, and diminished regenerative capacity, ultimately impairing liver homeostasis and functional reserve [2, 3].

A key molecular driver of inflammaging is the nucleotide-binding oligomerization domain (NOD)-like receptor family pyrin domain-containing protein 3 (NLRP3) inflammasome [4]. The NLRP3 inflammasome is a cytosolic multiprotein complex that detects cellular stress signals and activates caspase-1, resulting in the maturation and release of proinflammatory cytokines such as interleukin-1$\beta$ (IL-1$\beta$) and IL-18. Activation of the NLRP3 inflammasome is known to be enhanced in aged tissues, contributing to chronic inflammatory signaling, mitochondrial dysfunction, and impaired autophagic clearance [5]. In the liver, dysregulated NLRP3 signaling has been implicated in age-associated hepatocellular injury, steatohepatitis, and fibrosis, highlighting its potential as a therapeutic target for alleviating hepatic inflammaging [6].

Despite its pathogenic significance, pharmacological interventions targeting NLRP3 in the context of hepatic aging remain limited. MCC950 is a selective and potent small-molecule inhibitor of the NLRP3 inflammasome that prevents inflammasome assembly and caspase-1 activation without affecting other inflammasome complexes [7]. Preclinical studies have demonstrated the therapeutic benefit of MCC950 in metabolic, autoimmune, and neuroinflammatory disorders [5]; however, its effects on age-associated liver inflammation and tissue homeostasis have not been fully elucidated.

Therefore, the present study aimed to evaluate whether NLRP3 inhibition by MCC950 can attenuate inflammaging-related changes in the liver of aged mice. We assessed inflammatory cytokine expression, inflammasome activation, and autophagy-related markers to determine the therapeutic potential of MCC950 in restoring hepatic function during aging. Our findings provide evidence that MCC950 alleviates age-related hepatic inflammation and may serve as a promising strategy to preserve liver health in the elderly population.

In this study we demonstrate that aging is associated with increased NLRP3 inflammasome activation in the liver, which contributes to chronic low-grade inflammation and fibrotic susceptibility. We observed that aged mice exhibit higher NLRP3 expression, IL-1$\beta$ production, and fibrogenic markers compared to young mice. Importantly, interventions that either inhibit NLRP3 or restore autophagy were able to mitigate these age-related changes in our models. These findings identify the NLRP3 inflammasome as a key driver of liver “inflammaging” and fibrosis, and they suggest that targeting inflammasome activity or bolstering autophagic clearance could help preserve liver health in the elderly.

Aging fosters a pro-inflammatory milieu in the liver partly through the NLRP3 inflammasome [5]. Consistent with this, our findings show that aged livers exhibit elevated NLRP3 activation and inflammatory cytokine expression relative to young adults, which likely contributes to their increased susceptibility to liver injury and fibrosis. Prior studies similarly report that older mice develop more severe and persistent fibrosis than young mice following hepatic insults, coinciding with heightened NLRP3 levels, greater immune cell infiltration, and amplified fibrogenic activation [8]. Chronic metabolic conditions common in the elderly (such as NAFLD) may further exacerbate this pathway, as they lead to excessive NLRP3 activation and inflammatory tissue damage [5]. Taken together, the NLRP3 inflammasome emerges as a central mediator of age-related liver pathophysiology by driving ongoing inflammation and priming the liver for fibrotic remodeling.

Interestingly, our findings also highlight a divergence between human and murine aging with respect to NLRP3 expression. Specifically, analysis of the GTEx transcriptome data revealed no significant age-related increase in hepatic NLRP3 expression in healthy humans, consistent with previous reports indicating that sterile inflammation in human aging is often subtle and context-dependent [1, 9]. However, it should be noted that GTEx-derived human transcriptomic data represent a heterogeneous population and may be influenced by multiple confounding factors, including underlying comorbidities, medication use, lifestyle differences, and postmortem interval. Accordingly, the absence of a significant age-dependent change in hepatic NLRP3 mRNA levels in GTEx data should be interpreted with caution. This discrepancy may be attributable, at least in part, to regulatory processes beyond steady-state mRNA abundance (e.g., translational and protein turnover mechanisms) and to inherent differences between human donor-based transcriptomic datasets and controlled murine aging models. In the present study, GTEx analysis was used to provide contextual insight into human liver aging at the transcriptomic level, rather than to establish definitive causal relationships between aging and inflammasome activation. In contrast, our murine model exhibited a robust age-associated increase in hepatic NLRP3 protein expression, indicating more pronounced inflammasome activation during mouse liver aging, even in the absence of overt metabolic stress. These species-specific differences may reflect variations in immune surveillance, lifespan, or subclinical inflammatory burden, and underscore the inherent limitations of large-scale human postmortem datasets. Together, these findings highlight the value of complementary experimental models, such as spontaneously aged mice, for mechanistic investigation of age-related hepatic inflammation.

A major pathological consequence of NLRP3 inflammasome hyperactivation in the aging liver is the promotion of fibrosis. Persistent inflammasome signaling drives chronic release of IL-1$\beta$ and IL-18, which not only sustains hepatic inflammation but also activates hepatic stellate cells (HSCs), thereby accelerating extracellular matrix deposition. In aged organisms, inflammatory resolution is often impaired, predisposing the liver to exaggerated and prolonged fibrotic remodeling after injury. Consistently, older mice and young mice with loss of the anti-aging factor SIRT1, which enhances NLRP3 activity—exhibit heightened inflammatory infiltration, sustained HSC activation, and increased collagen accumulation compared with young controls [8]. Importantly, disrupting this pathway can mitigate fibrogenesis: both genetic deletion and pharmacological inhibition of NLRP3 reduce inflammatory cytokine signaling and improve fibrotic outcomes, supporting NLRP3-driven inflammaging as a mechanistic link between age-associated inflammation and hepatic fibrosis [10, 11, 12, 13].

Importantly, although pharmacological inhibition of NLRP3 with MCC950 has been reported to ameliorate liver inflammation and fibrosis in previous studies, most of these investigations were conducted in acute injury– or metabolically stressed models, such as toxin-induced or diet-induced liver disease [14]. In contrast, the present study specifically employed spontaneously aged mice, which develop hepatic inflammation and fibrotic susceptibility in the absence of overt exogenous insults. This distinction is critical, as spontaneous aging models more closely reflect the physiological and progressive nature of hepatic inflammaging, rather than secondary inflammatory responses driven by experimental injury. Therefore, our findings extend prior work by demonstrating that NLRP3 inflammasome activation is not merely a consequence of liver damage, but a primary driver of age-associated hepatic inflammation during natural aging.

Given its central involvement in age-related liver pathology, NLRP3 represents an attractive therapeutic target. MCC950, a highly selective small-molecule inhibitor of NLRP3, suppresses inflammasome assembly, thereby preventing caspase-1 activation and subsequent IL-1$\beta$ maturation and release [15, 16]. In aged mice, NLRP3 inhibition with MCC950 leads to reduced hepatic inflammation and improved tissue architecture. For example, Youm et al. [12] demonstrated that treating old, fibrogenic mice with MCC950 significantly attenuated liver inflammation and fibrosis, underscoring the inflammasome’s role in driving these aging phenotypes. Our findings concur, as MCC950-treated old mice exhibited lower inflammatory cytokine levels and reduced fibrotic scar formation relative to untreated aged controls. These outcomes highlight the translational potential of NLRP3 inhibitors in managing age-associated liver disorders characterized by excessive inflammation.

Restoring autophagy represents a complementary therapeutic axis to inflammasome blockade because autophagic flux declines with aging, allowing damaged organelles and protein aggregates to accumulate and provide endogenous danger signals that can prime and activate the NLRP3 inflammasome. Conversely, autophagy acts as a negative regulator of NLRP3 signaling by removing inflammasome activators (e.g., damaged mitochondria) and, in some contexts, limiting inflammasome components and cytokine output [17]. Notably, rather than reflecting a secondary consequence of reduced inflammatory burden, our data indicate that MCC950 treatment preferentially restores components of the early autophagy initiation machinery. Consistent with this bidirectional crosstalk, our data show that MCC950-mediated suppression of IL-1$\beta$/inflammasome activation is accompanied by recovery of autophagy-related proteins in aged liver, including increased LC3 processing and normalization of p62, together with restoration of the autophagy nucleation machinery (VPS34–ATG14L complex). This linkage is biologically plausible, as prior work reported that MCC950 treatment in aged mice improves hepatic/metabolic dysfunction while inhibiting PI3K/Akt/mTOR signaling and enhancing autophagy, as reflected by increased LC3-II and reduced p62 [14] Moreover, because VPS34 and ATG14L are core constituents of the class III PI3K complex required for autophagosome nucleation, their recovery strongly supports reactivation of early autophagy steps, rather than a downstream change in cargo degradation alone [18]. Taken together, our findings suggest that MCC950 may interrupt a self-reinforcing inflammasome–autophagy loop in the aging liver: by dampening NLRP3/IL-1$\beta$ output, MCC950 reduces inflammatory stress that otherwise impairs autophagic flux, thereby facilitating restoration of cellular quality-control pathways and promoting hepatic homeostasis during aging.

While our study provides important insights, several limitations should be acknowledged. First, murine findings may not directly translate to humans, as GTEx-based analyses suggest that age-related inflammasome changes in human liver are relatively subtle, warranting validation in elderly human cohorts. Second, the present study was conducted exclusively in male mice, which may limit the generalizability of our findings. Given well-documented sex-dependent differences in hepatic metabolism and inflammaging, future studies will incorporate female mice and apply appropriate experimental controls, such as estrous cycle staging or hormonal profiling, to comprehensively evaluate sex-specific effects. Third, MCC950 was administered for a relatively short duration in aged mice; therefore, the long-term efficacy, optimal treatment window, and safety of sustained NLRP3 inhibition remain to be determined. Finally, our analyses were largely performed at the whole-tissue level, and future work using cell-type–resolved approaches (e.g., single-cell profiling or conditional knockouts) will be required to define the principal hepatic cell populations driving NLRP3 activation and IL-1$\beta$ production during aging.

Taken together, our results indicate that targeting the NLRP3 inflammasome while restoring autophagy is an effective strategy to counter age-associated hepatic inflammation and fibrosis. By simultaneously reducing inflammasome-driven cytokine output and reactivating cellular quality-control pathways, this approach disrupts the self-perpetuating cycle of hepatic inflammaging. Although additional studies are required to establish translational applicability, our findings provide clear proof-of-concept that coordinated modulation of NLRP3 signaling and autophagy can improve liver homeostasis in aging.

The datasets generated and analyzed during the current study are available from the corresponding authors upon request.

KHK: Writing-original draft, Animal modeling, Investigation, Review & Editing. YWS: Animal modeling, Investigation. YJK: Animal modeling, Investigation. HJL: Animal modeling, Investigation. JLR: Investigation. HTK: Animal modeling. GLH: Investigation. JYJ: Conceptualization, Funding acquisition, Supervision, Project Administration. All authors contributed to editorial changes in the manuscript. All authors read and approved the final manuscript. All authors have participated sufficiently in the work and agreed to be accountable for all aspects of the work.

The animal experimental protocols were approved by the Institutional Animal Ethics Committee of Chungnam National University (approval number: 202307A-CNU-136). This study was conducted in accordance with the Guide for the Care and Use of Laboratory Animals of National Institutes of Health.

Not applicable.

This research was supported by the 2025 Daejeon RISE Project (DJR2025-12), funded by the Ministry of Education and Daejeon Metropolitan City, in the Republic of Korea. This work was supported by research fund of Chungnam National University.

The authors declare no conflict of interest.