bims-inflin 2024-09-15 papers

bims-inflin

Biomed News

on Inflammasome and infection

Issue of 2024–09–15
ten papers selected by
Juliane Cristina Ribeiro Fernandes, Faculdade de Medicina de Ribeirão Preto

NLRP1-dependent activation of Gasdermin D in neutrophils controls cutaneous leishmaniasis.
Starvation-induced phosphorylation activates gasdermin A to initiate pyroptosis.
S-acylation of NLRP3 provides a nigericin sensitive gating mechanism that controls access to the Golgi.
Small-molecule GSDMD agonism in tumors stimulates antitumor immunity without toxicity.
Glucose metabolite methylglyoxal induces vascular endothelial cell pyroptosis via NLRP3 inflammasome activation and oxidative stress in vitro and in vivo.
Inflammatory response and parasite regulation in acute toxoplasmosis: the role of P2X7 receptor in controlling virulent atypical genotype strain of Toxoplasma gondii.
Role of gasdermin D in inflammatory diseases: from mechanism to therapeutics.
Iron-depleting nutritional immunity controls extracellular bacterial replication in Legionella pneumophila infections.
HIF-α signaling regulates the macrophage inflammatory response during Leishmania major infection.
The unique Legionella longbeachae capsule favors intracellular replication and immune evasion.

PLoS Pathog. 2024 Sep 09. 20(9): e1012527

NLRP1-dependent activation of Gasdermin D in neutrophils controls cutaneous leishmaniasis.

Michiel Goris, Katiuska Passelli, Sanam Peyvandi, Miriam Díaz-Varela, Oaklyne Billion, Borja Prat-Luri, Benjamin Demarco, Chantal Desponds, Manon Termote, Eva Iniguez, Somaditya Dey, Bernard Malissen, Shaden Kamhawi, Benjamin P Hurrell, Petr Broz, Fabienne Tacchini-Cottier.

Intracellular pathogens that replicate in host myeloid cells have devised ways to inhibit the cell's killing machinery. Pyroptosis is one of the host strategies used to reduce the pathogen replicating niche and thereby control its expansion. The intracellular Leishmania parasites can survive and use neutrophils as a silent entry niche, favoring subsequent parasite dissemination into the host. Here, we show that Leishmania mexicana induces NLRP1- and caspase-1-dependent Gasdermin D (GSDMD)-mediated pyroptosis in neutrophils, a process critical to control the parasite-induced pathology. In the absence of GSDMD, we observe an increased number of infected dermal neutrophils two days post-infection. Using adoptive neutrophil transfer in neutropenic mice, we show that pyroptosis contributes to the regulation of the neutrophil niche early after infection. The critical role of neutrophil pyroptosis and its positive influence on the regulation of the disease outcome was further demonstrated following infection of mice with neutrophil-specific deletion of GSDMD. Thus, our study establishes neutrophil pyroptosis as a critical regulator of leishmaniasis pathology.

DOI: https://doi.org/10.1371/journal.ppat.1012527
Cell Rep. 2024 Sep 10. pii: S2211-1247(24)01079-9. [Epub ahead of print]43(9): 114728

Starvation-induced phosphorylation activates gasdermin A to initiate pyroptosis.

Xinran Li, Xiao Li, Cong Xiang, Jin Cao, Jiansheng Guo, Shilei Zhu, Jingyi Tan, Lijing Wang, Chun Gao, Shengduo Liu, Lifeng Zhao, Bo Yuan, Pinglong Xu, Bing Yang, Dali Li, Bin Zhao, Xin-Hua Feng.

  Pyroptosis, a pro-inflammatory form of programmed cell death, is crucial for host defense against pathogens and danger signals. Proteolytic cleavage of gasdermin proteins B-E (GSDMB-GSDME) is well established as a trigger for pyroptosis, but the intracellular activation mechanism of GSDMA remains elusive. Here, we demonstrate that severe starvation induces pyroptosis through phosphorylation-induced activation of GSDMA. Nutrient stresses stimulate GSDMA activation via phosphorylation mediated by Unc-51-like autophagy-activating kinase 1 (ULK1). Phosphorylation of Ser353 on human GSDMA by ULK1 or the phospho-mimetic Ser353Asp mutant of GSDMA liberates GSDMA from auto-inhibition, facilitating its membrane targeting and initiation of pyroptosis. To further validate the significance of GSDMA phosphorylation, we generated a constitutively active mutant Ser354Asp of mouse Gsdma, which induced skin inflammation and hyperplasia in mice, reminiscent of phenotypes with activated Gsdma. This study uncovers phosphorylation of GSDMA as a mechanism underlying pyroptosis initiation and cellular response to nutrient stress.

Keywords:  CP: Immunology; CP: Metabolism; GSDMA; ULK1; gastric cancer; phosphorylation; pyroptotic cell death; skin inflammation; starvation

DOI:  https://doi.org/10.1016/j.celrep.2024.114728
Elife. 2024 Sep 12. pii: RP94302. [Epub ahead of print]13

S-acylation of NLRP3 provides a nigericin sensitive gating mechanism that controls access to the Golgi.

Daniel M Williams, Andrew A Peden.

  NLRP3 is an inflammasome seeding pattern recognition receptor activated in response to multiple danger signals which perturb intracellular homeostasis. Electrostatic interactions between the NLRP3 polybasic (PB) region and negatively charged lipids on the trans-Golgi network (TGN) have been proposed to recruit NLRP3 to the TGN. In this study, we demonstrate that membrane association of NLRP3 is critically dependant on S-acylation of a highly conserved cysteine residue (Cys-130), which traps NLRP3 in a dynamic S-acylation cycle at the Golgi, and a series of hydrophobic residues preceding Cys-130 which act in conjunction with the PB region to facilitate Cys-130 dependent Golgi enrichment. Due to segregation from Golgi localised thioesterase enzymes caused by a nigericin induced breakdown in Golgi organisation and function, NLRP3 becomes immobilised on the Golgi through reduced de-acylation of its Cys-130 lipid anchor, suggesting that disruptions in Golgi homeostasis are conveyed to NLRP3 through its acylation state. Thus, our work defines a nigericin sensitive S-acylation cycle that gates access of NLRP3 to the Golgi.

Keywords:  Golgi; cell biology; human; immunology; inflammasomes; inflammation; lipidation; membrane trafficking

DOI:  https://doi.org/10.7554/eLife.94302
Cell. 2024 Sep 02. pii: S0092-8674(24)00898-5. [Epub ahead of print]

Small-molecule GSDMD agonism in tumors stimulates antitumor immunity without toxicity.

Pietro Fontana, Gang Du, Ying Zhang, Haiwei Zhang, Setu M Vora, Jun Jacob Hu, Ming Shi, Ahmet B Tufan, Liam B Healy, Shiyu Xia, Dian-Jang Lee, Zhouyihan Li, Pilar Baldominos, Heng Ru, Hongbo R Luo, Judith Agudo, Judy Lieberman, Hao Wu.

  Gasdermin-mediated inflammatory cell death (pyroptosis) can activate protective immunity in immunologically cold tumors. Here, we performed a high-throughput screen for compounds that could activate gasdermin D (GSDMD), which is expressed widely in tumors. We identified 6,7-dichloro-2-methylsulfonyl-3-N-tert-butylaminoquinoxaline (DMB) as a direct and selective GSDMD agonist that activates GSDMD pore formation and pyroptosis without cleaving GSDMD. In mouse tumor models, pulsed and low-level pyroptosis induced by DMB suppresses tumor growth without harming GSDMD-expressing immune cells. Protection is immune-mediated and abrogated in mice lacking lymphocytes. Vaccination with DMB-treated cancer cells protects mice from secondary tumor challenge, indicating that immunogenic cell death is induced. DMB treatment synergizes with anti-PD-1. DMB treatment does not alter circulating proinflammatory cytokine or leukocyte numbers or cause weight loss. Thus, our studies reveal a strategy that relies on a low level of tumor cell pyroptosis to induce antitumor immunity and raise the possibility of exploiting pyroptosis without causing overt toxicity.

Keywords:  GSDMD; GSDMD agonist; antitumor immunity; cancer; checkpoint blockade; gasdermin; immunogenic cell death; immunotherapy; pyroptosis; tumor

DOI:  https://doi.org/10.1016/j.cell.2024.08.007
Cell Mol Life Sci. 2024 Sep 13. 81(1): 401

Glucose metabolite methylglyoxal induces vascular endothelial cell pyroptosis via NLRP3 inflammasome activation and oxidative stress in vitro and in vivo.

Yanan Wang, Jinxiang Chen, Youkun Zheng, Jun Jiang, Liqun Wang, Jianbo Wu, Chunxiang Zhang, Mao Luo.

  Methylglyoxal (MGO), a reactive dicarbonyl metabolite of glucose, plays a prominent role in the pathogenesis of diabetes and vascular complications. Our previous studies have shown that MGO is associated with increased oxidative stress, inflammatory responses and apoptotic cell death in endothelial cells (ECs). Pyroptosis is a novel form of inflammatory caspase-1-dependent programmed cell death that is closely associated with the activation of the NOD-like receptor 3 (NLRP3) inflammasome. Recent studies have shown that sulforaphane (SFN) can inhibit pyroptosis, but the effects and underlying mechanisms by which SFN affects MGO-induced pyroptosis in endothelial cells have not been determined. Here, we found that SFN prevented MGO-induced pyroptosis by suppressing oxidative stress and inflammation in vitro and in vivo. Our results revealed that SFN dose-dependently prevented MGO-induced HUVEC pyroptosis, inhibited pyroptosis-associated biochemical changes, and attenuated MGO-induced morphological alterations in mitochondria. SFN pretreatment significantly suppressed MGO-induced ROS production and the inflammatory response by inhibiting the NLRP3 inflammasome (NLRP3, ASC, and caspase-1) signaling pathway by activating Nrf2/HO-1 signaling. Similar results were obtained in vivo, and we demonstrated that SFN prevented MGO-induced oxidative damage, inflammation and pyroptosis by reversing the MGO-induced downregulation of the NLRP3 signaling pathway through the upregulation of Nrf2. Additionally, an Nrf2 inhibitor (ML385) noticeably attenuated the protective effects of SFN on MGO-induced pyroptosis and ROS generation by inhibiting the Nrf2/HO-1 signaling pathway, and a ROS scavenger (NAC) and a permeability transition pore inhibitor (CsA) completely reversed these effects. Moreover, NLRP3 inhibitor (MCC950) and caspase-1 inhibitor (VX765) further reduced pyroptosis in endothelial cells that were pretreated with SFN. Collectively, these findings broaden our understanding of the mechanism by which SFN inhibits pyroptosis induced by MGO and suggests important implications for the potential use of SFN in the treatment of vascular diseases.

Keywords:  MGO; NLRP3 inflammasome; Pyroptosis; ROS; Sulforaphane

DOI:  https://doi.org/10.1007/s00018-024-05432-8
Front Immunol. 2024 ;15 1452828

Inflammatory response and parasite regulation in acute toxoplasmosis: the role of P2X7 receptor in controlling virulent atypical genotype strain of Toxoplasma gondii.

Thuany Prado-Rangel, Aline Cristina Abreu Moreira-Souza, Sthefani Rodrigues Batista da Silva, Thais Barboza-Araujo, Archimedes Barbosa Castro-Junior, Isalira Peroba Rezende Ramos, Christina Maeda Takiya, Rossiane Claudia Vommaro, Robson Coutinho-Silva.

  Toxoplasmosis is a globally significant disease that poses a severe threat to immunocompromised individuals, especially in Brazil, where a high prevalence of virulent and atypical strains of Toxoplasma gondii is observed. In 1998, the EGS strain, exhibiting a unique infection phenotype, was isolated in Brazil, adding to the complexity of strain diversity. The P2X7 receptor is critical in inflammation and controlling intracellular microorganisms such as T. gondii. However, its genetic variability can result in receptor dysfunction, potentially worsening susceptibility. This study investigates the role of the P2X7 receptor during acute infection induced by the EGS atypical strain, offering insight into the mechanisms of T. gondii infection in this context. We infected the female C57BL/6 (WT) or P2X7 knockout (P2X7-/-) by gavage. The EGS infection causes intestinal inflammation. The P2X7-/- mice presented higher parasite load in the intestine, spleen, and liver. The absence of the P2X7 receptor disrupts inflammatory cell balance by reducing NLRP3, IL-1β, and Foxp3 expression while increasing IFN-γ expression and production in the intestine. In the liver, P2X7-/- animals demonstrate diminished inflammatory infiltrate within the portal and lobular regions concurrent with an enlargement of the spleen. In conclusion, the infection of mice with the EGS strain elicited immune alterations, leading to acute inflammation and cytokine dysregulation, while the P2X7 receptor conferred protection against parasitic proliferation across multiple organs.

Keywords:  Brazilian strain; EGS strain; inflammation; parasite control; purinergic signaling; toxoplasmosis

DOI:  https://doi.org/10.3389/fimmu.2024.1452828
Front Immunol. 2024 ;15 1456244

Role of gasdermin D in inflammatory diseases: from mechanism to therapeutics.

Chak Kwong Cheng, Min Yi, Li Wang, Yu Huang.

  Inflammatory diseases compromise a clinically common and diverse group of conditions, causing detrimental effects on body functions. Gasdermins (GSDM) are pore-forming proteins, playing pivotal roles in modulating inflammation. Belonging to the GSDM family, gasdermin D (GSDMD) actively mediates the pathogenesis of inflammatory diseases by mechanistically regulating different forms of cell death, particularly pyroptosis, and cytokine release, in an inflammasome-dependent manner. Aberrant activation of GSDMD in different types of cells, such as immune cells, cardiovascular cells, pancreatic cells and hepatocytes, critically contributes to the persistent inflammation in different tissues and organs. The contributory role of GSDMD has been implicated in diabetes mellitus, liver diseases, cardiovascular diseases, neurodegenerative diseases, and inflammatory bowel disease (IBD). Clinically, alterations in GSDMD levels are potentially indicative to the occurrence and severity of diseases. GSDMD inhibition might represent an attractive therapeutic direction to counteract the progression of inflammatory diseases, whereas a number of GSDMD inhibitors have been shown to restrain GSDMD-mediated pyroptosis through different mechanisms. This review discusses the current understanding and future perspectives on the role of GSDMD in the development of inflammatory diseases, as well as the clinical insights of GSDMD alterations, and therapeutic potential of GSDMD inhibitors against inflammatory diseases. Further investigation on the comprehensive role of GSDM shall deepen our understanding towards inflammation, opening up more diagnostic and therapeutic opportunities against inflammatory diseases.

Keywords:  GSDMD inhibitor; NEtosis; cell death; gasdermin D; inflammation; inflammatory diseases; necroptosis; pyroptosis

DOI:  https://doi.org/10.3389/fimmu.2024.1456244
Nat Commun. 2024 Sep 08. 15(1): 7848

Iron-depleting nutritional immunity controls extracellular bacterial replication in Legionella pneumophila infections.

Ascención Torres-Escobar, Ashley Wilkins, María D Juárez-Rodríguez, Magdalena Circu, Brian Latimer, Ana-Maria Dragoi, Stanimir S Ivanov.

The accidental human pathogen Legionella pneumophila (Lp) is the etiological agent for a severe atypical pneumonia known as Legionnaires' disease. In human infections and animal models of disease alveolar macrophages are the primary cellular niche that supports bacterial replication within a unique intracellular membrane-bound organelle. The Dot/Icm apparatus-a type IV secretion system that translocates ~300 bacterial proteins within the cytosol of the infected cell-is a central virulence factor required for intracellular growth. Mutant strains lacking functional Dot/Icm apparatus are transported to and degraded within the lysosomes of infected macrophages. The early foundational work from Dr. Horwitz's group unequivocally established that Legionella does not replicate extracellularly during infection-a phenomenon well supported by experimental evidence for four decades. Our data challenges this paradigm by demonstrating that macrophages and monocytes provide the necessary nutrients and support robust Legionella extracellular replication. We show that the previously reported lack of Lp extracellular replication is not a bacteria intrinsic feature but rather a result of robust restriction by serum-derived nutritional immunity factors. Specifically, the host iron-sequestering protein Transferrin is identified here as a critical suppressor of Lp extracellular replication in an iron-dependent manner. In iron-overload conditions or in the absence of Transferrin, Lp bypasses growth restriction by IFNγ-primed macrophages though extracellular replication. It is well established that certain risk factors associated with development of Legionnaires' disease, such as smoking, produce a chronic pulmonary environment of iron-overload. Our work indicates that iron-overload could be an important determinant of severe infection by allowing Lp to overcome nutritional immunity and replicate extracellularly, which in turn would circumvent intracellular cell intrinsic host defenses. Thus, we provide evidence for nutritional immunity as a key underappreciated host defense mechanism in Legionella pathogenesis.

DOI: https://doi.org/10.1038/s41467-024-52184-x
bioRxiv. 2024 Aug 27. pii: 2024.08.27.605844. [Epub ahead of print]

HIF-α signaling regulates the macrophage inflammatory response during Leishmania major infection.

Lucy G Fry, Charity L Washam, Hayden Roys, Anne K Bowlin, Gopinath Venugopal, Jordan T Bird, Stephanie D Byrum, Tiffany Weinkopff.

Cutaneous leishmaniasis (CL) contributes significantly to the global burden of neglected tropical diseases, with 12 million people currently infected with Leishmania parasites. CL encompasses a range of disease manifestations, from self-healing skin lesions to permanent disfigurations. Currently there is no vaccine available, and many patients are refractory to treatment, emphasizing the need for new therapeutic targets. Previous work demonstrated macrophage HIF-α-mediated lymphangiogenesis is necessary to achieve efficient wound resolution during murine L. major infection. Here, we investigate the role of macrophage HIF-α signaling independent of lymphangiogenesis. We sought to determine the relative contributions of the parasite and the host-mediated inflammation in the lesional microenvironment to myeloid HIF-α signaling. Because HIF-α activation can be detected in infected and bystander macrophages in leishmanial lesions, we hypothesize it is the host's inflammatory response and microenvironment, rather than the parasite, that triggers HIF-α activation. To address this, macrophages from mice with intact HIF-α signaling (LysM Cre ARNT f/+ ) or mice with deleted HIF-α signaling (LysM Cre ARNT f/f ) were subjected to RNASequencing after L. major infection and under pro-inflammatory stimulus. We report that L. major infection alone is enough to induce some minor HIF-α-dependent transcriptomic changes, while infection with L. major in combincation with pro-inflammatory stimuli induces numerous transcriptomic changes that are both dependent and independent of HIF-α signaling. Additionally, by coupling transcriptomic analysis with several pathway analyses, we found HIF-α suppresses pathways involved in protein translation during L. major infection in a pro-inflammatory environment. Together these findings show L. major induces a HIF-α-dependent transcriptomic program, but HIF-α only suppresses protein translation in a pro-inflammatory environment. Thus, this work indicates the host inflammatory response, rather than the parasite, largely contributes to myeloid HIF-α signaling during Leishmania infection.

DOI: https://doi.org/10.1101/2024.08.27.605844
PLoS Pathog. 2024 Sep 11. 20(9): e1012534

The unique Legionella longbeachae capsule favors intracellular replication and immune evasion.

Silke Schmidt, Sonia Mondino, Laura Gomez-Valero, Pedro Escoll, Danielle P A Mascarenhas, Augusto Gonçalves, Pedro H M Camara, Francisco J Garcia Rodriguez, Christophe Rusniok, Martin Sachse, Maryse Moya-Nilges, Thierry Fontaine, Dario S Zamboni, Carmen Buchrieser.

Legionella longbeachae and Legionella pneumophila are the most common causative agents of Legionnaires' disease. While the clinical manifestations caused by both species are similar, species-specific differences exist in environmental niches, disease epidemiology, and genomic content. One such difference is the presence of a genomic locus predicted to encode a capsule. Here, we show that L. longbeachae indeed expresses a capsule in post-exponential growth phase as evidenced by electron microscopy analyses, and that capsule expression is abrogated when deleting a capsule transporter gene. Capsule purification and its analysis via HLPC revealed the presence of a highly anionic polysaccharide that is absent in the capsule mutant. The capsule is important for replication and virulence in vivo in a mouse model of infection and in the natural host Acanthamoeba castellanii. It has anti-phagocytic function when encountering innate immune cells such as human macrophages and it is involved in the low cytokine responses in mice and in human monocyte derived macrophages, thus dampening the innate immune response. Thus, the here characterized L. longbeachae capsule is a novel virulence factor, unique among the known Legionella species, which may aid L. longbeachae to survive in its specific niches and which partly confers L. longbeachae its unique infection characteristics.

DOI: https://doi.org/10.1371/journal.ppat.1012534