bims-inflin 2024-08-25 papers

bims-inflin

Biomed News

on Inflammasome and infection

Issue of 2024–08–25
ten papers selected by
Juliane Cristina Ribeiro Fernandes, Faculdade de Medicina de Ribeirão Preto

Atg16l2 augments Nlrc4 inflammasome activation by facilitating NAIPs-NLRC4 association.
Non-canonical autophosphorylation of RIPK1 drives timely pyroptosis to control Yersinia infection.
Influenza A virus infection activates caspase-8 to enhance innate antiviral immunity by cleaving CYLD and blocking TAK1 and RIG-I deubiquitination.
Classical apoptotic stimulus, staurosporine, induces lytic inflammatory cell death, PANoptosis.
Consecutive palmitoylation and phosphorylation orchestrates NLRP3 membrane trafficking and inflammasome activation.
IL-1β mediates Candida tropicalis-induced immunosuppressive function of MDSCs to foster colorectal cancer.
The miR-26a/SIRT6/HIF-1α axis regulates glycolysis and inflammatory responses in host macrophages during Mycobacterium tuberculosis infection.
Inhibition of Caspase-1-dependent pyroptosis alleviates myocardial ischemia/reperfusion injury during cardiopulmonary bypass (CPB) in type 2 diabetic rats.
NLRP3 inflammasome inhibition decreases Schistosomiasis japonica-induced granulomatous inflammation and fibrosis in BALB/c mice.
Permissive lung neutrophils facilitate tuberculosis immunopathogenesis in male phagocyte NADPH oxidase-deficient mice.

Eur J Immunol. 2024 Aug 22. e2451078

Atg16l2 augments Nlrc4 inflammasome activation by facilitating NAIPs-NLRC4 association.

Zhoujin Wen, Tianli Yuan, Jiamin Liu, Dongyang Wang, Jun Ni, Xuehan Yan, Jian Tang, Jiayin Tang, Xuefeng Wu, Zheng Wang.

  As cytoplasmic protein complexes that are pivotal for innate immunity, inflammasomes act primarily through the detection of pathogen- or danger-associated molecular patterns. Nucleotide oligomerisation domain-like receptor family and caspase activation recruitment domain-containing protein 4 (NLRC4) inflammasomes identify and eliminate intracellular pathogens, a process contingent on the ligand-recognition capabilities of neuronal apoptosis inhibitory proteins (NAIPs). Upon detection of specific molecules indicative of intracellular infection, NAIPs discern distinct pathogenic components and subsequently transmit signals to NLRC4, thus initiating their activation and triggering an inflammatory response. However, the mechanisms underlying NLRC4 inflammasome remain unclear. In this study, we elucidated the critical role of ATG16L2 in activating the NLRC4 inflammasome. ATG16L2-deficient macrophages exhibited reduced NLRC4 inflammasome activation, characterised by decreased oligomerisation of apoptosis-associated speck-like protein containing a CARD and attenuated cleavage of Pro-caspase-1, Pro-IL-1β and gasdermin D. Co-immunoprecipitation assays revealed an interaction between ATG16L2 and NAIPs. Furthermore, ATG16L2 enhanced the association between NAIPs and NLRC4 by binding to NAIPs. For ATG16L2-knockout mice infected with Salmonella typhimurium, pathogen clearance and survival rates markedly decreased. Collectively, our findings suggest that ATG16L2 is a significant modulator of the innate immune system, influencing the activity of the NLRC4 inflammasome and the host's defensive response to intracellular pathogens.

Keywords:  ATG16L2; GSDMD; Inflammasome; Macrophage; NAIPs

DOI:  https://doi.org/10.1002/eji.202451078
Cell Rep. 2024 Aug 17. pii: S2211-1247(24)00991-4. [Epub ahead of print]43(8): 114641

Non-canonical autophosphorylation of RIPK1 drives timely pyroptosis to control Yersinia infection.

David Jetton, Hayley I Muendlein, Wilson M Connolly, Zoie Magri, Irina Smirnova, Rebecca Batorsky, Joan Mecsas, Alexei Degterev, Alexander Poltorak.

  Caspase-8-dependent pyroptosis has been shown to mediate host protection from Yersinia infection. For this mode of cell death, the kinase activity of receptor-interacting protein kinase 1 (RIPK1) is required, but the autophosphorylation sites required to drive caspase-8 activation have not been determined. Here, we show that non-canonical autophosphorylation of RIPK1 at threonine 169 (T169) is necessary for caspase-8-mediated pyroptosis. Mice with alanine in the T169 position are highly susceptible to Yersinia dissemination. Mechanistically, the delayed formation of a complex containing RIPK1, ZBP1, Fas-associated protein with death domain (FADD), and caspase-8 abrogates caspase-8 maturation in T169A mice and leads to the eventual activation of RIPK3-dependent necroptosis in vivo; however, this is insufficient to protect the host, suggesting that timely pyroptosis during early response is specifically required to control infection. These results position RIPK1 T169 phosphorylation as a driver of pyroptotic cell death critical for host defense.

Keywords:  CP: Immunology; CP: Microbiology; RIPK1; Yersinia pseudotuberculosis; YopJ; autophosphorylation; caspase-8; macrophages; necroptosis; pyroptosis

DOI:  https://doi.org/10.1016/j.celrep.2024.114641
Cell Mol Life Sci. 2024 Aug 19. 81(1): 355

Influenza A virus infection activates caspase-8 to enhance innate antiviral immunity by cleaving CYLD and blocking TAK1 and RIG-I deubiquitination.

Huidi Yu, Yuling Sun, Jingting Zhang, Wenhui Zhang, Wei Liu, Penggang Liu, Kaituo Liu, Jing Sun, Hailiang Liang, Pinghu Zhang, Xiaoquan Wang, Xiufan Liu, Xiulong Xu.

  Caspase-8, an aspartate-specific cysteine protease that primarily functions as an initiator caspase to induce apoptosis, can downregulate innate immunity in part by cleaving RIPK1 and IRF3. However, patients with caspase-8 mutations or deficiency develop immunodeficiency and are prone to viral infections. The molecular mechanism underlying this controversy remains unknown. Whether caspase-8 enhances or suppresses antiviral responses against influenza A virus (IAV) infection remains to be determined. Here, we report that caspase-8 is readily activated in A549 and NL20 cells infected with the H5N1, H5N6, and H1N1 subtypes of IAV. Surprisingly, caspase-8 deficiency and two caspase-8 inhibitors, Z-VAD and Z-IETD, do not enhance but rather downregulate antiviral innate immunity, as evidenced by decreased TBK1, IRF3, IκBα, and p65 phosphorylation, decreased IL-6, IFN-β, MX1, and ISG15 gene expression; and decreased IFN-β production but increased virus replication. Mechanistically, caspase-8 cleaves and inactivates CYLD, a tumor suppressor that functions as a deubiquitinase. Caspase-8 inhibition suppresses CYLD cleavage, RIG-I and TAK1 ubiquitination, and innate immune signaling. In contrast, CYLD deficiency enhances IAV-induced RIG-I and TAK1 ubiquitination and innate antiviral immunity. Neither caspase-3 deficiency nor treatment with its inhibitor Z-DEVD affects CYLD cleavage or antiviral innate immunity. Our study provides evidence that caspase-8 activation in two human airway epithelial cell lines does not silence but rather enhances innate immunity by inactivating CYLD.

Keywords:  CYLD; Caspase-8; Influenza A virus; Innate immunity; RIPK1

DOI:  https://doi.org/10.1007/s00018-024-05392-z
J Biol Chem. 2024 Aug 14. pii: S0021-9258(24)02177-X. [Epub ahead of print] 107676

Classical apoptotic stimulus, staurosporine, induces lytic inflammatory cell death, PANoptosis.

Roman Sarkar, Sk Mohiuddin Choudhury, Thirumala-Devi Kanneganti.

  Innate immunity is the body's first line of defense against disease, and regulated cell death is a central component of this response that balances pathogen clearance and inflammation. Cell death pathways are generally categorized as non-lytic and lytic. While non-lytic apoptosis has been extensively studied in health and disease, lytic cell death pathways are increasingly implicated in infectious and inflammatory diseases and cancers. Staurosporine (STS) is a well-known inducer of non-lytic apoptosis. However, in this study, we observed that STS also induces lytic cell death at later timepoints. Using biochemical assessments with genetic knockouts, pharmacological inhibitors, and gene silencing, we identified that STS triggered PANoptosis via the caspase-8/RIPK3 axis, which was mediated by RIPK1. PANoptosis is a unique, lytic, innate immune cell death pathway initiated by innate immune sensors and driven by caspases and RIPKs through PANoptosome complexes. Deletion of caspase-8 and RIPK3, core components of the PANoptosome complex, protected against STS-induced lytic cell death. Overall, our study identifies STS as a time-dependent inducer of lytic inflammatory cell death, PANoptosis. These findings emphasize the importance of understanding trigger- and time-specific activation of distinct cell death pathways to advance our understanding of the molecular mechanisms of innate immunity and cell death for clinical translation.

Keywords:  MLKL; PANoptosis; PANoptosome; RIPK1; RIPK3; Staurosporine; apoptosis; caspase; caspase-1; caspase-3; caspase-7; caspase-8; caspase-9; cell death; gasdermin; inflammasome; innate immunity; macrophages; necroptosis; pyroptosis

DOI:  https://doi.org/10.1016/j.jbc.2024.107676
Mol Cell. 2024 Aug 18. pii: S1097-2765(24)00633-6. [Epub ahead of print]

Consecutive palmitoylation and phosphorylation orchestrates NLRP3 membrane trafficking and inflammasome activation.

Li Nie, Chenjie Fei, Yizeng Fan, Fabin Dang, Ziyue Zhao, Tingfang Zhu, Xiangyu Wu, Ting Dai, Arumugam Balasubramanian, Jing Pan, Yang Hu, Hongbo R Luo, Wenyi Wei, Jiong Chen.

  NLRP3 inflammasome activation, essential for cytokine secretion and pyroptosis in response to diverse stimuli, is closely associated with various diseases. Upon stimulation, NLRP3 undergoes subcellular membrane trafficking and conformational rearrangements, preparing itself for inflammasome assembly at the microtubule-organizing center (MTOC). Here, we elucidate an orchestrated mechanism underlying these ordered processes using human and murine cells. Specifically, NLRP3 undergoes palmitoylation at two sites by palmitoyl transferase zDHHC1, facilitating its trafficking between subcellular membranes, including the mitochondria, trans-Golgi network (TGN), and endosome. This dynamic trafficking culminates in the localization of NLRP3 to the MTOC, where LATS1/2, pre-recruited to MTOC during priming, phosphorylates NLRP3 to further facilitate its interaction with NIMA-related kinase 7 (NEK7), ultimately leading to full NLRP3 activation. Consistently, Zdhhc1-deficiency mitigated LPS-induced inflammation and conferred protection against mortality in mice. Altogether, our findings provide valuable insights into the regulation of NLRP3 membrane trafficking and inflammasome activation, governed by palmitoylation and phosphorylation events.

Keywords:  LATS1/2; NLRP3; inflammasome activation; membrane trafficking; microtubule-organizing center; palmitoylation; phosphorylation; zDHHC1

DOI:  https://doi.org/10.1016/j.molcel.2024.08.001
Cell Commun Signal. 2024 Aug 21. 22(1): 408

IL-1β mediates Candida tropicalis-induced immunosuppressive function of MDSCs to foster colorectal cancer.

Zhiyong Zhang, Ying Chen, Xinyi Pan, Pengfei Li, Zhengqian Ren, Xiuzhu Wang, Yuxi Chen, Sunan Shen, Tingting Wang, Aihua Lin.

   BACKGROUND: There is increasing evidence that gut fungi dysbiosis plays a crucial role in the development and progression of colorectal cancer (CRC). It has been reported that gut fungi exacerbate the severity of CRC by regulating tumor immunity. Our previous studies have shown that the opportunistic pathogenic fungal pathogen, Candida tropicalis (C. tropicalis) promotes CRC progression by enhancing the immunosuppressive function of MDSCs and activating the NLRP3 inflammasome of MDSCs. However, the relationship between IL-1β produced by NLRP3 inflammasome activation and the immunosuppressive function of MDSCs enhanced by C. tropicalis in CRC remains unclear.
METHODS: The TCGA database was used to analyze the relationship between IL-1β and genes related to immunosuppressive function of MDSCs in human CRC. The expression of IL-1β in human CRC tissues was detected by immunofluorescence staining. The proteomic analysis was performed on the culture supernatant of C. tropicalis-stimulated MDSCs. The experiments of supplementing and blocking IL-1β as well as inhibiting the NLRP3 inflammasome activation were conducted. A mouse colon cancer xenograft model was established by using MC38 colon cancer cell line.
RESULTS: Analysis of CRC clinical samples showed that the high expression of IL-1β was closely related to the immunosuppressive function of tumor-infiltrated MDSCs. The results of in vitro experiments revealed that IL-1β was the most secreted cytokine of MDSCs stimulated by C. tropicalis. In vitro supplementation of IL-1β further enhanced the immunosuppressive function of C. tropicalis-stimulated MDSCs and NLRP3-IL-1β axis mediated the immunosuppressive function of MDSCs enhanced by C. tropicalis. Finally, blockade of IL-1β secreted by MDSCs augmented antitumor immunity and mitigated C. tropicalis-associated colon cancer.
CONCLUSIONS: C. tropicalis promotes excessive secretion of IL-1β from MDSCs via the NLRP3 inflammasome. IL-1β further enhances the immunosuppressive function of MDSCs to inhibit antitumor immunity, thus promoting the progression of CRC. Therefore, targeting IL-1β secreted by MDSCs may be a potential immunotherapeutic strategy for the treatment of CRC.

Keywords:   Candida tropicalis ; CRC; IL-1β; MDSCs; NLRP3

DOI:  https://doi.org/10.1186/s12964-024-01771-y
FEBS Lett. 2024 Aug 18.

The miR-26a/SIRT6/HIF-1α axis regulates glycolysis and inflammatory responses in host macrophages during Mycobacterium tuberculosis infection.

Soumya Mal, Debayan Majumder, Pankaj Birari, Arun Kumar Sharma, Umesh Gupta, Kuladip Jana, Manikuntala Kundu, Joyoti Basu.

  Mycobacterium tuberculosis (Mtb) is the causative agent of tuberculosis. Here, a macrophage infection model was used to unravel the role of the histone deacetylase sirtuin 6 (SIRT6) in Mtb-triggered regulation of the innate immune response. Mtb infection downregulated microRNA-26a and upregulated its target SIRT6. SIRT6 suppressed glycolysis and expression of HIF-1α-dependent glycolytic genes during infection. In addition, SIRT6 regulated the levels of intracellular succinate which controls stabilization of HIF-1α, as well as the release of interleukin (IL)-1β. Furthermore, SIRT6 inhibited inducible nitric oxide synthase (iNOS) and proinflammatory IL-6 but augmented anti-inflammatory arginase expression. The miR-26a/SIRT6/HIF-1α axis therefore regulates glycolysis and macrophage immune responses during Mtb infection. Our findings link SIRT6 to rewiring of macrophage signaling pathways facilitating dampening of the antibacterial immune response.

Keywords:  Mycobacterium tuberculosis; glycolysis; immunometabolism; innate immunity; macrophage response; sirtuin 6

DOI:  https://doi.org/10.1002/1873-3468.15001
Sci Rep. 2024 08 21. 14(1): 19420

Inhibition of Caspase-1-dependent pyroptosis alleviates myocardial ischemia/reperfusion injury during cardiopulmonary bypass (CPB) in type 2 diabetic rats.

Wenjing Zhou, Yingya Yang, Zhouheng Feng, Yu Zhang, Yiman Chen, Tian Yu, Haiying Wang.

  Cardiovascular complications pose a significant burden in type 2 diabetes mellitus (T2DM), driven by the intricate interplay of chronic hyperglycemia, insulin resistance, and lipid metabolism disturbances. Myocardial ischemia/reperfusion (MI/R) injury during cardiopulmonary bypass (CPB) exacerbates cardiac vulnerability. This study aims to probe the role of Caspase-1-dependent pyroptosis in global ischemia/reperfusion injury among T2DM rats undergoing CPB, elucidating the mechanisms underlying heightened myocardial injury in T2DM. This study established a rat model of T2DM and compared Mean arterial pressure (MAP), heart rate (HR), and hematocrit (Hct) between T2DM and normal rats. Myocardial cell morphology, infarction area, mitochondrial ROS and caspase-1 levels, NLRP3, pro-caspase-1, caspase-1 p10, GSDMD expressions, plasma CK-MB, cTnI, IL-1β, and IL-18 levels were assessed after reperfusion in both T2DM and normal rats. The role of Caspase-1-dependent pyroptosis in myocardial ischemia/reperfusion injury during CPB in T2DM rats was examined using the caspase-1 inhibitor VX-765 and the ROS scavenger NAC. T2DM rats demonstrated impaired glucose tolerance but stable hemodynamics during CPB, while showing heightened vulnerability to MI/R injury. This was marked by substantial lipid deposition, disrupted myocardial fibers, and intensified cellular apoptosis. The activation of caspase-1-mediated pyroptosis and increased reactive oxygen species (ROS) production further contributed to tissue damage and the ensuing inflammatory response. Notably, myocardial injury was mitigated by inhibiting caspase-1 through VX-765, which also attenuated the inflammatory cascade. Likewise, NAC treatment reduced oxidative stress and partially suppressed ROS-mediated caspase-1 activation, resulting in diminished myocardial injury. This study proved that Caspase-1-dependent pyroptosis significantly contributes to the inflammation and injury stemming from global MI/R in T2DM rats under CPB, which correlate with the surplus ROS generated by oxidative stress during reperfusion.

Keywords:  Cardiopulmonary bypass; Caspase-1; Myocardial ischemia/reperfusion injury; Pyroptosis; Type 2 diabetes mellitus

DOI:  https://doi.org/10.1038/s41598-024-70477-5
Infect Immun. 2024 Aug 19. e0005524

NLRP3 inflammasome inhibition decreases Schistosomiasis japonica-induced granulomatous inflammation and fibrosis in BALB/c mice.

Yaqi Lu, Jing Liu, Wangxian Tang, Heng Zhang.

  To research the role of the NLRP3 inflammasome in Schistosoma japonicum-induced granuloma formation and liver fibrosis. In in vivo tests, BALB/c mice were used. shNLRP3 plasmid based on adeno-associated virus serotype 8 (AAV8-shNLRP3) was injected to block NLRP3 inflammasome via tail vein. Serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels were detected to assess liver injury. H&E staining was used for routine histopathological assessment; Masson's trichrome staining was used to detect fibrous tissues and collagen fibers. Hepatic expression of NLRP3, procaspase-1, bioactive caspase-1, collagen-1, tissue inhibitor of metalloproteinases-1 (TIMP-1), and α-smooth muscle actin (α-SMA) were detected by western blot. Serum levels of IL-1β were detected by enzyme-linked immunosorbent assay (ELISA). The inflammatory cell infiltration and hepatic expression of IL-1β around the granuloma were detected by immunohistochemistry staining. Treatment of S. japonicum infected mice with AAV8-shNLRP3 significantly reduced the hepatic levels of bioactive caspase-1 and IL-1β, as well as circulating IL-1β concentrations, while reducing the amounts of myeloperoxidase (MPO) and F4/80 positive cells around the granuloma. Moreover, collagen deposition, TIMP-1, and α-SMA, which are markers of hepatic stellate cell (HSC) activation, were reduced around the liver granuloma. These findings highlight a therapeutic potential of AAV8-shNLRP3 in schistosomiasis cirrhosis.

Keywords:  NLRP3 inflammasome; Schistosoma japonicum; granulomatous inflammation; liver fibrosis

DOI:  https://doi.org/10.1128/iai.00055-24
PLoS Pathog. 2024 Aug 23. 20(8): e1012500

Permissive lung neutrophils facilitate tuberculosis immunopathogenesis in male phagocyte NADPH oxidase-deficient mice.

Eunsol Choi, Hong-Hee Choi, Kee Woong Kwon, Hagyu Kim, Ji-Hwan Ryu, Jung Joo Hong, Sung Jae Shin.

NADPH oxidase 2 (NOX2) is an enzyme responsible for generating reactive oxygen species, primarily found in phagocytes. Chronic Granulomatous Disease (CGD), along with bacterial infections such as Mycobacterium tuberculosis (Mtb), is a representative NOX2-deficient X-linked disease characterized by uncontrolled inflammation. However, the precise roles of host-derived factors that induce infection-mediated hyperinflammation in NOX2-deficient condition remain incompletely understood. To address this, we compared Mtb-induced pathogenesis in Nox2-/- and wild type (WT) mice in a sex-dependent manner. Among age- and sex-matched mice subjected to Mtb infection, male Nox2-/- mice exhibited a notable increase in bacterial burden and lung inflammation. This was characterized by significantly elevated pro-inflammatory cytokines such as G-CSF, TNF-α, IL-1α, IL-1β, and IL-6, excessive neutrophil infiltration, and reduced pulmonary lymphocyte levels as tuberculosis (TB) progressed. Notably, lungs of male Nox2-/- mice were predominantly populated with CD11bintLy6GintCXCR2loCD62Llo immature neutrophils which featured mycobacterial permissiveness. By diminishing total lung neutrophils or reducing immature neutrophils, TB immunopathogenesis was notably abrogated in male Nox2-/- mice. Ultimately, we identified G-CSF as the pivotal trigger that exacerbates the generation of immature permissive neutrophils, leading to TB immunopathogenesis in male Nox2-/- mice. In contrast, neutralizing IL-1α and IL-1β, which are previously known factors responsible for TB pathogenesis in Nox2-/- mice, aggravated TB immunopathogenesis. Our study revealed that G-CSF-driven immature and permissive pulmonary neutrophils are the primary cause of TB immunopathogenesis and lung hyperinflammation in male Nox2-/- mice. This highlights the importance of quantitative and qualitative control of pulmonary neutrophils to alleviate TB progression in a phagocyte oxidase-deficient condition.

DOI: https://doi.org/10.1371/journal.ppat.1012500