bims-cediti 2025-04-06 papers

bims-cediti

Biomed News

on Cell death in innate immunity, inflammation, and tissue repair

Issue of 2025–04–06
eight papers selected by
Kateryna Shkarina, Universität Bonn

Pyroptosis of pulmonary fibroblasts and macrophages through NLRC4 inflammasome leads to acute respiratory failure.
Pyroptosis: molecular mechanisms and roles in disease.
NEDD4 E3 ligase-catalyzed NAMPT ubiquitination and autophagy activation are essential for pyroptosis-independent NAMPT secretion in human monocytes.
Inflammasomes primarily restrict cytosolic Salmonella replication within human macrophages.
PLC and PAD2 Regulate Extracellular Calcium-Triggered Release of Macrophage Extracellular DNA Traps.
ExoS effector in Pseudomonas aeruginosa Hyperactive Type III secretion system mutant promotes enhanced Plasma Membrane Rupture in Neutrophils.
The critical role of the ZBP1-NINJ1 axis and IRF1/IRF9 in ethanol-induced cell death, PANoptosis, and alcohol-associated liver disease.
GI-Y2, a novel gasdermin D inhibitor, attenuates sepsis-induced myocardial dysfunction by inhibiting gasdermin D-mediated pyroptosis in macrophages.

Cell Rep. 2025 Mar 29. pii: S2211-1247(25)00250-5. [Epub ahead of print]44(4): 115479

Pyroptosis of pulmonary fibroblasts and macrophages through NLRC4 inflammasome leads to acute respiratory failure.

Yan Zhang, Guoying Zhang, Brittany Dong, Ankit Pandeya, Jian Cui, Samuel Dos Santos Valenca, Ling Yang, Jiaqian Qi, Zhuodong Chai, Congqing Wu, Daniel Kirchhofer, Toshihiko Shiroishi, Fadi Khasawneh, Min Tao, Feng Shao, Christopher M Waters, Yinan Wei, Zhenyu Li.

  The NAIP/NLRC4 inflammasome plays a pivotal role in the defense against bacterial infections, with its in vivo physiological function primarily recognized as driving inflammation in immune cells. Acute lung injury (ALI) is a leading cause of mortality in sepsis. In this study, we identify that the NAIP/NLRC4 inflammasome is highly expressed in both macrophages and pulmonary fibroblasts and that pyroptosis of these cells plays a critical role in lung injury. Mice challenged with gram-negative bacteria or flagellin developed lethal lung injury, characterized by reduced blood oxygen saturation, disrupted lung barrier function, and escalated inflammation. Flagellin-induced lung injury was protected in caspase-1 or GSDMD-deficient mice. These findings enhance our understanding of the NAIP/NLRC4 inflammasome's (patho)physiological function and highlight the significant role of inflammasome activation and pyroptosis in ALI during sepsis.

Keywords:  CP: Immunology; inflammasome; lung injury; pyroptosis; sepsis

DOI:  https://doi.org/10.1016/j.celrep.2025.115479
Cell Res. 2025 Apr 03.

Pyroptosis: molecular mechanisms and roles in disease.

Petr Broz.

Pyroptosis is a type of programmed necrosis triggered by the detection of pathogens or endogenous danger signals in the cytosol. Pyroptotic cells exhibit a swollen, enlarged morphology and ultimately undergo lysis, releasing their cytosolic contents - such as proteins, metabolites, and nucleic acids - into the extracellular space. These molecules can function as danger-associated molecular patterns (DAMPs), triggering inflammation when detected by neighboring cells. Mechanistically, pyroptosis is initiated by members of the gasdermin protein family, which were identified a decade ago as pore-forming executors of cell death. Mammalian gasdermins consist of a cytotoxic N-terminal domain, a flexible linker, and a C-terminal regulatory domain that binds to and inhibits the N-terminus. Proteolytic cleavage within the linker releases the N-terminal domain, enabling it to target various cellular membranes, including nuclear, mitochondrial, and plasma membranes, where it forms large transmembrane pores. Gasdermin pores in the plasma membrane disrupt the electrochemical gradient, leading to water influx and cell swelling. Their formation also activates the membrane protein ninjurin-1 (NINJ1), which oligomerizes to drive complete plasma membrane rupture and the release of large DAMPs. Since their discovery as pore-forming proteins, gasdermins have been linked to pyroptosis not only in host defense but also in various pathological conditions. This review explores the history of pyroptosis, recent insights into gasdermin activation, the cellular consequences of pore formation, and the physiological roles of pyroptosis.

DOI: https://doi.org/10.1038/s41422-025-01107-6
Cell Commun Signal. 2025 Mar 30. 23(1): 157

NEDD4 E3 ligase-catalyzed NAMPT ubiquitination and autophagy activation are essential for pyroptosis-independent NAMPT secretion in human monocytes.

Marisela Rodriguez, Haifei Xu, Annie Hernandez, Julia Ingraham, Jason Canizales, Fernando Teran Arce, Sara M Camp, Skyler Briggs, Aikseng Ooi, James M Burke, Jin H Song, Joe G N Garcia.

  NAMPT is an important intracellular metabolic enzyme (iNAMPT) regulating the NAD+ salvage pathway. However, increased cellular stress (infection, inflammation, hypoxia) promotes the secretion of extracellular NAMPT (eNAMPT), a TLR4 ligand and damage-associated molecular pattern protein (DAMP) that directly drives amplification of innate immune-mediated inflammatory, fibrotic, and neoplastic responses to influence disease severity. We sought to examine the mechanisms underlying pyroptotic eNAMPT release from human monocytic THP-1 cells, evoked by Nigericin, and non-pyroptotic eNAMPT secretion elicited by lipopolysaccharide (LPS). Our data indicate eNAMPT secretion/release requires NLRP3 inflammasome activation with substantial attenuation by either NLRP3 inhibition (MCC-950) or targeted genetic deletion of key inflammasome components, including NLRP3, caspase-1, or gasdermin D (GSDMD). Pyroptosis-associated eNAMPT release involved cleavage of the pore-forming GSDMD protein resulting in plasma membrane rupture (PMR) whereas non-pyroptotic LPS-induced eNAMPT secretion involved neither GSDMD cleavage nor PMR, verified utilizing non-cleavable GSDMD mutant constructs. LPS-induced eNAMPT secretion, however, was highly dependent upon NAMPT ubiquitination catalyzed by a complex containing the NEDD4 E3 ligase, Hsp90 (a selective chaperone), and intact GSDMD verified by enzymatic inhibition or silencing of NEDD4, GSDMD, or Hsp90. NAMPT ubiquitination and secretion involves autophagy activation as super-resolution microscopy analyses demonstrate NAMPT co-localization with autophagosome marker LC3B and eNAMPT secretion was significantly reduced by targeted ATG5 and ATG7 inhibition, critical components of the autophagy E3-like complex. These studies provide key insights into eNAMPT secretion that may accelerate the development of therapeutic strategies that address unmet therapeutic needs in inflammatory, fibrotic and neoplastic disorders.

Keywords:  Autophagy; DAMP; Gasdermin D; NLRP3 inflammasome; Pyroptosis; Ubiquitination; eNAMPT

DOI:  https://doi.org/10.1186/s12964-025-02164-5
Elife. 2025 Mar 27. pii: RP90107. [Epub ahead of print]12

Inflammasomes primarily restrict cytosolic Salmonella replication within human macrophages.

Marisa S Egan, Emily A O'Rourke, Shrawan Kumar Mageswaran, Biao Zuo, Inna Martynyuk, Tabitha Demissie, Emma N Hunter, Antonia R Bass, Yi-Wei Chang, Igor E Brodsky, Sunny Shin.

  Salmonella enterica serovar Typhimurium is a facultative intracellular pathogen that utilizes its type III secretion systems (T3SSs) to inject virulence factors into host cells and colonize the host. In turn, a subset of cytosolic immune receptors respond to T3SS ligands by forming multimeric signaling complexes called inflammasomes, which activate caspases that induce interleukin-1 (IL-1) family cytokine release and an inflammatory form of cell death called pyroptosis. Human macrophages mount a multifaceted inflammasome response to Salmonella infection that ultimately restricts intracellular bacterial replication. However, how inflammasomes restrict Salmonella replication remains unknown. We find that caspase-1 is essential for mediating inflammasome responses to Salmonella and restricting bacterial replication within human macrophages, with caspase-4 contributing as well. We also demonstrate that the downstream pore-forming protein gasdermin D (GSDMD) and Ninjurin-1 (NINJ1), a mediator of terminal cell lysis, play a role in controlling Salmonella replication in human macrophages. Notably, in the absence of inflammasome responses, we observed hyperreplication of Salmonella within the cytosol of infected cells as well as increased bacterial replication within vacuoles, suggesting that inflammasomes control Salmonella replication primarily within the cytosol and also within vacuoles. These findings reveal that inflammatory caspases and pyroptotic factors mediate inflammasome responses that restrict the subcellular localization of intracellular Salmonella replication within human macrophages.

Keywords:  Salmonella enterica serovar Typhimurium; human; human macrophages; immunology; infectious disease; inflammasomes; inflammation; microbiology; salmonella enterica serovar typhimurium

DOI:  https://doi.org/10.7554/eLife.90107
Eur J Immunol. 2025 Apr;55(4): e202350942

PLC and PAD2 Regulate Extracellular Calcium-Triggered Release of Macrophage Extracellular DNA Traps.

Neha Mishra, Magdalena Mohs, Nico Wittmann, Stefan Gross, Paul R Thompson, Lukas Bossaller.

  Macrophages can respond to infection or cellular stress by forming inflammasomes or by releasing extracellular traps (ETs) of DNA through METosis. While ETs have been extensively studied in neutrophils, there are fewer studies on METosis. We show that extracellular calcium and LPS enable human monocyte-derived macrophages (hMDM) to release extracellular DNA decorated with myeloperoxidase (MPO) and citrullinated histone, alongside ASC aggregation and IL-1ß maturation, indicating NLRP3 inflammasome activation. Compared with m-CSF differentiated macrophages only gm-CSF differentiated macrophages expressed macrophage elastase (MMP12) and METs released by the latter had significantly more bactericidal activity toward E. coli. Mechanistically, phospholipase C and peptidyl arginine deiminase-2 inhibition attenuate MET release. Interestingly, NLRP3 inflammasome blockade by MCC950 had a significant effect on MET release. Finally, MET release was completely blocked by plasma membrane stabilization by punicalagin. Altogether, we demonstrate that extracellular calcium-activated hMDM extrude DNA, containing citrullinated histones, MPO, MMP12, and ASC specks and released METs kill bacteria independent of hMDM phagocytotic activity. We believe that calcium-activated hMDM adds a physiologically relevant condition to calcium ionophore induced cell death that may be important in autoimmunity.

Keywords:  cell death; citrullination; extracellular calcium; inflammasomes; macrophage extracellular DNA traps

DOI:  https://doi.org/10.1002/eji.202350942
PLoS Pathog. 2025 Apr 02. 21(4): e1013021

ExoS effector in Pseudomonas aeruginosa Hyperactive Type III secretion system mutant promotes enhanced Plasma Membrane Rupture in Neutrophils.

Arianna D Reuven, Sarah Katzenell, Bethany W Mwaura, James B Bliska.

Pseudomonas aeruginosa is an opportunistic pathogen responsible for airway infections in immunocompromised individuals, including those with cystic fibrosis (CF). P. aeruginosa has a type III secretion system (T3SS) that translocates effectors into host cells. ExoS is a T3SS effector with ADP ribosyltransferase (ADPRT) activity. ExoS ADPRT activity promotes P. aeruginosa virulence by inhibiting phagocytosis and limiting oxidative burst in neutrophils. The P. aeruginosa T3SS also translocates flagellin, which can activate the NLRC4 inflammasome, resulting in: 1) gasdermin-D pores, release of IL-1β and pyroptosis; and 2) histone 3 citrullination (CitH3), nuclear DNA decondensation and expansion into the neutrophil cytosol with incomplete NET extrusion. However, studies with P. aeruginosa PAO1 indicate that ExoS ADPRT activity inhibits the NLRC4 inflammasome in neutrophils. Here, we identified an ExoS+ CF clinical isolate of P. aeruginosa with a hyperactive T3SS. Variants of the hyperactive T3SS mutant or PAO1 were used to infect neutrophils from C57BL/6 mice that were wildtype or engineered to have a CF genotype or defects in inflammasome assembly. Responses to NLRC4 inflammasome assembly or ExoS ADPRT activity were assayed and found to be similar for C57BL/6 or CF neutrophils. ExoS ADPRT activity in the hyperactive T3SS mutant regulated inflammasome, nuclear DNA decondensation and incomplete NET extrusion responses, like PAO1, but promoted enhanced CitH3 and plasma membrane rupture (PMR). Glycine supplementation inhibited PMR by the hyperactive T3SS mutant, suggesting ninjurin-1 is required for this process. These results identify enhanced neutrophil PMR as a pathogenic activity of ExoS ADPRT in hypervirulent P. aeruginosa.

DOI: https://doi.org/10.1371/journal.ppat.1013021
bioRxiv. 2025 Mar 14. pii: 2025.03.12.642836. [Epub ahead of print]

The critical role of the ZBP1-NINJ1 axis and IRF1/IRF9 in ethanol-induced cell death, PANoptosis, and alcohol-associated liver disease.

Qiang Qin, Wen Chen, Clay D King, Sivakumar Prasanth Kumar, Peter Vogel, Rebecca E Tweedell, Thirumala-Devi Kanneganti.

Innate immunity provides the critical first line of defense against infection and sterile triggers. Cell death is a key component of the innate immune response to clear pathogens, but excessive or aberrant cell death can induce inflammation, cytokine storm, and pathology, making it a central molecular mechanism in inflammatory diseases. Alcohol-associated liver disease (ALD) is one such inflammatory disease, but the specific innate immune mechanisms driving pathology in this context remain unclear. Here, by leveraging RNAseq and tissue expression in clinical samples, we identified increased expression of the innate immune sensor Z-DNA binding protein (ZBP1) in patients with ALD. We discovered that ZBP1 expression correlated with ALD progression in patients, and that ethanol induced ZBP1-dependent lytic cell death, PANoptosis, in immune (macrophages, monocytes, Kupffer cells) and non-immune cells (hepatocytes). Mechanistically, the interferon regulatory factors (IRFs) IRF9 and IRF1 upregulated ZBP1 expression, allowing ZBP1 to sense Z-NAs through its Zα2 domain and drive PANoptosis signaling, cell membrane rupture through NINJ1, and DAMP release. Furthermore, the expressions of ZBP1 and NINJ1 were upregulated in both liver and serum samples from patients with ALD. In mouse models of chronic and acute ALD, ZBP1-deficient mice were significantly protected from disease pathology and liver damage. Overall, our findings establish the critical role of the ZBP1-NINJ1 axis regulated by IRFs in driving inflammatory cell death, PANoptosis, in liver cells, suggesting that targeting these molecules will have therapeutic potential in ALD and other inflammatory conditions.

DOI: https://doi.org/10.1101/2025.03.12.642836
Br J Pharmacol. 2025 Mar 31.

GI-Y2, a novel gasdermin D inhibitor, attenuates sepsis-induced myocardial dysfunction by inhibiting gasdermin D-mediated pyroptosis in macrophages.

Yiling Mei, Xudong Chen, Si Shi, Wante Lin, Zhenfeng Cheng, Xiaoxi Fan, Wenqi Wu, Jibo Han, Weijian Huang, Bozhi Ye, Shanshan Dai.

   BACKGROUND AND PURPOSE: Myocardial dysfunction is a significant complication associated with sepsis. However, there are currently no specific and effective treatments available. Inhibiting gasdermin D (GSDMD)-mediated pyroptosis has shown promise in mitigating sepsis-induced myocardial dysfunction. The GSDMD inhibitor Y2 (GI-Y2) has been demonstrated to directly bind to GSDMD. Nonetheless, it remains uncertain whether GI-Y2 offers a cardioprotective effect in the context of sepsis-induced myocardial dysfunction.
EXPERIMENTAL APPROACH: A mouse model of sepsis was created using lipopolysaccharide (LPS), caecal ligation and puncture. Following treatment with GI-Y2 or macrophage membrane-encapsulated GI-Y2 nanoparticles (GI-Y2@MM-NPs), myocardial dysfunction and pyroptosis levels in heart tissues were assessed. Transcriptome sequencing revealed the molecular mechanism of GI-Y2 in treating septic cardiomyopathy.
KEY RESULTS: We observed that GI-Y2 alleviated myocardial dysfunction and attenuated cardiac inflammation in mice induced by LPS, caecal ligation and puncture. GI-Y2 reduced macrophage pyroptosis and attenuated macrophage-mediated cardiomyocyte injury induced by LPS/nigericin. Concurrently, we confirmed the protective effect of GI-Y2 against LPS-induced cardiac dysfunction was abolished in the absence of GSDMD. Additionally, GI-Y2 attenuated the mitochondrial damage induced by LPS by inhibiting GSDMD in the mitochondria. Furthermore, we developed GI-Y2@MM-NPs to enhance the targeting capability of GI-Y2 towards macrophages in heart tissues and demonstrated its protective effect in vivo.
CONCLUSION AND IMPLICATIONS: These findings indicate that GI-Y2 alleviates septic myocardial injury and dysfunction by specifically targeting GSDMD, thereby inhibiting GSDMD-mediated pyroptosis and mitochondrial damage. Both GI-Y2 and GI-Y2@MM-NPs may serve as promising therapeutic options for addressing septic myocardial dysfunction.

Keywords:  GI‐Y2; GSDMD; Pyroptosis; inhibitor; septic cardiomyopathy

DOI:  https://doi.org/10.1111/bph.70040