bluuebunny/crossref_metadata_2025_split huggingface dataset:
A multi-component bacterial toxin incites host inflammation via the NLRP3 inflammasome
Authors: Mathur Anukriti , Feng Shouya , Hayward Jenni A. , Ngo Chinh , Fox Daniel , Man Si Ming 
Published: January 2023

Abstract
Innate immune recognition of microbial components serves as a cornerstone in mediating an effective immune response. The inflammasome is an intracellular signaling complex comprising of a sensor, an adaptor protein ASC and the cysteine protease caspase-1. Inflammasomes regulate secretion of the pro-inflammatory cytokines IL-1β and IL-18 and induction of a cell death pathway known as pyroptosis. Certain intracellular bacteria require cytosolic access to activate the inflammasome, however, how extracellular bacteria are sensed by the cytoplasmic inflammasome remains unclear. To understand innate immune recognition of extracellular bacteria, we analyzed a panel of clinically important intracellular and extracellular bacteria and identified an unknown secreted factor from the foodborne bacterium Bacillus cereus that activates the inflammasome without gaining cytosolic access. The tripartite enterotoxin called haemolysin BL (HBL) was identified as the novel activator of the NLRP3 inflammasome. The multi-component toxin assembled in a linear order on the mammalian cell membrane to form a pore, which induces potassium efflux and activates the NLRP3 inflammasome. Furthermore, HBL-producing B. cereus induced rapid lethality in the host via activation of the NLRP3 inflammasome. B. cereus-induced lethality was completely abrogated with administration of the NLRP3 inhibitor, MCC950. Our unpublished results further show that the transmembrane region of the apical subunit of HBL is dispensable for membrane binding but essential for inflammasome activation. Overall, our results indicate that intracellular sensing of a toxin secreted by an extracellular bacterium is critical for the innate immune recognition of infection.
Inflammasome activation by members of the Bacillus genus
Authors: Shen Cheng , Feng Shouya , Man Si Ming 
Published: January 2023

Abstract
Inflammasome activation induced by microbial components leads to an effective innate immune response. Bacillus anthracis is able to induce activation of the NLRP1b inflammasome, whereas B. cereus can induce activation of the NLRP3 inflammasome. However, whether different strains of B. cereus have differential ability to induce activation of the inflammasome has not been investigated. Further, whether other members of the Bacillus genus can induce activation of the inflammasome has remained unknown. Here, we screened 46 B. cereus strains from environmental and clinical sources to determine whether novel inflammasomes are activated. We infected primary mouse bone marrow-derived macrophages with bacteria or bacteria-free supernatant and observed for pyroptosis and other classical features of inflammasome activation. Strikingly, over 90% (42/46) of the B. cereus strains induced inflammasome activation as measured by caspase-1 cleavage and robust secretion of IL-1b, IL-18 and LDH. We identified that the inflammasome sensor NLRP3 was necessary to drive this response. Further, we confirmed that HBL and/or NHE toxins were expressed in all 42 B. cereus strains, suggesting a conserved inflammasome activation pattern amongst B. cereus strains. We also identified that four pathogenic Bacillus species induced inflammasome activation in an NLRP3-dependent manner, including B. idriensis, B. mycoides, B. pseudomycoides and B. thurigiensis. These findings highlight that the NLRP3 inflammasome sensor is important for immune recognition of several Bacillus species and suggest that therapeutic modulation of NLRP3 may enhance host protection against these Bacillus infections.
Regulation of the immune response by Siglec-1 through phosphorylation of Src at Ser17
Authors: Yang Darong , Wu Yin , Chen Guo-Yun 
Published: January 2023

Abstract

Introduction
Dysregulated host responses to infection usually cause severe immune diseases, including sepsis. TLR4 sensing of bacterial LPS is pivotal in the pathogenesis of sepsis. Identifying new regulatory mechanisms of TLR4 signaling will reveal the pathogenesis of inflammatory diseases and provide therapeutic targets.

Results
Silencing the immune regulatory receptor Siglec-1 in RAW 264.7 cells dramatically lowered LPS-induced Src phosphorylation at Ser17 (unknown function site) but not at Tyr416 and Tyr527, two critical sites that determine Src kinase activity. By contrast, P38, NF-kB, JNK, ERK, Syk and PKC phosphorylation triggered by LPS remained comparable between control and Siglec-1 knockdown cells. Strikingly, LPS induced Src phosphorylation at Ser17 in WT but not in Siglec-1−/− BMDMs; no defects were observed on Tyr416 and Tyr527 sites. Specifically blocking Ser17 phosphorylation of Src with H89 inhibitor remarkably decreased LPS-induced inflammatory cytokine secretion in WT BMDMs. Co-IP identified a novel interaction between Siglec-1 and Src. The S17A but not S17D mutation of Src attenuated its interaction with Siglec-1. Furthermore, to elucidate the role of Src-S17 in vivo, we successfully prepared three different knockin mice for Src-WT, Src-S17A or Src-S17D on the Src knockout background. Future investigations in Src knockin mice will determine how Src-Ser17 controls the immune response during infection with bacteria or LPS treatment.

Conclusion
Src phosphorylation at Ser17 is controlled by Siglec-1 and involved in the regulation of TLR4 inflammatory pathway. Pharmacological targeting of Src-Ser17 may provide promising strategies to combat inflammatory diseases.
Non-haemolytic enterotoxin induces pore-formation and activation of the inflammasome and pyroptosis
Authors: Fox Daniel R , Mathur Anukriti , Xue Yansong , Liu Yunqi , Tan Wei Hong , Feng Shouya , Pandey Abhimanu , Ngo Chinh , Hayward Jenni , Man Si Ming 
Published: January 2023

Abstract
Inflammasomes are central to innate immunity mediating host defence against pathogens and maintaining homeostasis with commensal microbes. The sensing of pathogens, danger, or homeostasis-altering signals by inflammasome sensor proteins is the molecular basis driving assembly of the inflammasome complex. Here, we identify non-haemolytic enterotoxin (NHE) as an activator of the NLRP3 inflammasome. We show that NHE, found in the neglected human foodborne pathogen Bacillus cereus, is a non-redundant toxin to haemolysin BL (HBL) despite exhibiting a similar mechanism of action. NHE-induced activation of NLRP3 has a delayed kinetic to that induced by HBL. Subunit C of NHE, via its putative transmembrane region, initiates binding to the plasma membrane, leading to the recruitment of subunit B and subunit A, forming a tripartite lytic pore permissive to efflux of potassium. NHE mediates killing of cells from multiple lineages and hosts, highlighting its versatile functional repertoire in different host species. Moreover, our data suggest that both NHE and HBL operate synergistically to induce inflammation in the host. Overall, our results highlight that multiple virulence factors from the same pathogen exhibiting conserved function and mechanism of action can be exploited for sensing by a single inflammasome, ultimately leading to increased capacity of the host to detect and defend against naturally-occurring genetic variants.
Functional macrophage chromatin landscapes depend on HMGN1/HMGN2
Authors: Sung Mia , Babagana Mahamat , Oh Kyu-Seon , Chakraborty Sayantan , Pacholewska Alicja , Furusawa Takashi , Bustin Michael 
Published: January 2023

Abstract
The High Mobility Group (HMG) proteins are ubiquitously present in the nuclei of all vertebrate cells. HMG proteins bind dynamically to chromatin without DNA sequence specificity, and they affect DNA-dependent functions such as replication, repair, and transcription, but only in the context of chromatin. HMGs are also suggested to play an important role in the immune system. Both HMGB1 and HMGN1 can act as alarmins. HMGN proteins also affect the response of B lymphocytes to bacterial LPS stimulation. HMGN proteins are typically enriched at regulatory sites such as enhancers and promoters, and have been shown to affect the chromatin landscape, suggesting a role in epigenetic regulatory processes. In LPS-stimulated bone marrow-derived macrophages (BMDMs), most HMG genes are downregulated in response to LPS (Oh KS et al, 2017 Immunity, PMID: 28801231. To understand the role of HMG proteins in the regulation of macrophage chromatin, we performed RNA-seq and ATAC-seq on BMDMs and two tissue-resident macrophage populations from mice lacking both HMGN1 and HMGN2. We identified several hundred differentially expressed genes in BMDMs with a large gene cluster showing female-specific downregulation in the double knockout. In peritoneal macrophages, the largest differentially expressed gene cluster was from the female-specific upregulated genes. The most dramatic transcriptome-wide changes were observed in microglia. Interestingly, MHC genes were commonly upregulated in macrophages from mutant mice. Together with alterations in chromatin, this raises the possibility that HMGNs maintain functional macrophage enhancers with specificity for the resident tissue.
Flightless-1 promotes lung CD103+ cDC phagocytosis and migration
Authors: O’Rourke Allison R , Hamerman Jessica A 
Published: January 2023

Abstract
Dendritic cells are specialized antigen-presenting cells integral for bridging the innate and adaptive immune responses. Critical to dendritic cell function is the need for a dynamic actin cytoskeleton. Flightless-1 is an actin capping protein linked to processes vital for dendritic cell immune functions including cell extension formation, phagocytosis, cell migration, and cell adhesion. Consistent with an important role in actin dynamics, whole body Flightless-1 knockouts are embryonic lethal. To enable further study of Flightless-1 in the immune response, we made mice with dendritic cell Flightless-1 deficiency using the CD11c-CRE driver. Homeostatic cDC1 and cDC2 populations in the spleen and lymph nodes were unchanged in DC-Flightless-1 knockouts relative to control animals. However, DC-Flightless-1 ablation led to a developmental disadvantage when in competition with WT DCs in mixed bone marrow chimeras. Upon LPS challenge in the airways, the Flightless-deficient cDC1 population showed reduced phagocytosis and migration to the lung draining lymph nodes. The DC migratory defect in the absence of Flightless-1 was supported by decreased CCR7 expression in both cDC1 and cDC2 populations. We hypothesize that the observed defects in phagocytosis and migration in Flightless-1-deficient dendritic cells are due to an altered actin cytoskeleton, which may also affect other actin-based immune structures. Current experiments are testing this hypothesis, and investigating the ability of Flightless-deficient DC to prime T cell responses.
Enhancing Anti-Tumor Activity of Natural Killer Cells by Upregulating Amino Acid Transporters
Authors: Lee Seung-Hwan , Jo Donghyeon , Almutairi Saeedah , Ali Alaa 
Published: January 2023

Abstract
In spite of the superior efficacy of NK cells against hematological cancers such as acute myeloid leukemia (AML), the poor ability of NK cells to infiltrate solid tumors, such as breast cancer or colorectal carcinoma, limits the potential NK cells for cancer immunotherapy. Diverse approaches are now being undertaken to overcome this limitation by modifying NK cells for better recognition and effector function of NK cells. One of the efforts is to genetically engineer NK cells to express chimeric antigen receptors (CARs) for new tumor recognition and migration to the tumor, resulting in enhanced tumor killing.
Here, we propose to enhance the anti-tumor activity of natural killer cells by upregulating amino acid transporters. Our laboratory recently showed that the upregulation of amino acid transporter is correlated with enhanced NK cell effector function. In particular, the upregulation of leucine amino acid transporter, CD98/LAT1, can induce leucine-driven mTORC1 activation and metabolic transformation, leading to enhanced proliferation and effector function of NK cells. Therefore, we will enhance the metabolism of NK cells by genetically modifying to upregulate the CD98/LAT1 nutrient transporter and make them more potent and sustained in vivo. In order to be the players in anti-tumor immunity, NK cells need to survive in the metabolically hostile conditions of the tumor microenvironment, where they have to compete for nutrients with metabolically active cancerous cells. We expect that combing our approach to augmenting the metabolism of NK cells with enhanced tumor recognition of CAR-NK cells could maximize the efficacy of cancer immunotherapy.
Resveratrol mediates regulation of genes through microRNAs in the gut epithelial cells that may play a role in the gut health and amelioration of EAE in mice
Authors: Singh Narendra Prasad , Chandler Zhane , Ezeanya Nneora , Nagarkatti Prakash S , Nagarkatti Mitzi 
Published: January 2023

Abstract
Resveratrol (RES), found abundantly in red grapes, blue berries and peanuts, is an anti-inflammatory, anticancer, and antioxidant compound. We have previously shown that RES ameliorated EAE in mice regulating immune cell functions and differentiation. In this study, we investigated the effect of RES on gene expression in the gut epithelial cells of mice with EAE. To this end, epithelial cells from small intestine (SI) and colons of mice with EAE treated with vehicle or RES were isolated. Transcriptome arrays using total RNAs from epithelial cells of SI and colons were performed and data obtained from the arrays were analyzed using Transcriptome Analysis Console software. Results showed that there were 1,591 (1165 in SI and 426 in colon) genes that were up- or down-regulated (&gt;2-fold) in the epithelial cells of mice with EAE treated with RES, when compared to vehicle. We selected two genes, α-defensins and Mucin 3, for further analysis. Upon analysis of their expression in the gut epithelial cells, α-defensins was downregulated in SI while Mucin 3 was upregulated in colon of EAE mice treated with RES. To understand the regulation of these two genes in the gut, we investigated the role of microRNAs (miRs). There were two miRs, miR-378 and miR-338, that showed strong binding affinity for α-defensins and Mucin 3 respectively. Upon analysis of their expression in epithelial cells, miR-378 was upregulated but miR-338 was downregulated, demonstrating their possible role in the regulation of α-defensins and Mucin 3 genes. Data obtained from this study demonstrates a possible role of miRs in the regulation of genes in the gut epithelial cells may play a role in improving the health of the gut and amelioration of EAE in mice.
IL9 immune score predict better survival and IL9+ILC2 and Th9 are orchestrated by estrogen
Authors: Tong Huan , Feng Hao , Wan Xiaoping 
Published: January 2023

Abstract

PURPOSE
Phenotyping immune cell subtypes are essential to determine the role of the endometrial immune niche in endometrial carcinoma (EC) development, which could facilitate the development of therapeutics and to improve outcomes.

METHODS
The tumor-infiltrating lymphocytes isolated from EC and normal tissues were analyzed by mass cytometry (CyTOF) to evaluate the activity of antitumor immunity. Tissue microarrays (TMAs) of endometrial tumors including 128 subjects were used for immunofluorescence staining of parameters of interest. The combined impact of clinical and immune parameters (such as γδT cells, interleukin-9+cells, and ILC2 cells) on survival was analyzed using log-rank testing and Cox regression analyses.

RESULTS
CyTOF assessment revealed significant remodeling of both the lymphoid and myeloid intratumoral compartments. The density of IL9+immune cells was associated with improved overall survival(OS) in univariate analysis (p=0.0027). As in EC, &gt;90% Vδ2 T cells expressed IL9, and Vδ2 T cells were reported as a major source of IL9, we supposed that the density of γδ T cells was also relevant to OS. However, in multivariate analysis, only IL9 and tumor stages but not the density of γδ T cells was linked to an altered prognosis.
Thus, we investigated the tissue resident IL9 expression and found that IL9 was mainly secreted by γδ T cells, ILC2, and Th9 cells in normal tissue. However, in tumor tissues, IL9 was hardly detected in ILC2 cells.
Next, the cytokine profile of infiltrating ILC2 and Th9 cells was investigated by CyTOF in endometrial hyperplasia, early and late stage of EC, and in PTEN genetic EC mice model. We found that the multifunctional roles of ILC2s and Th9 cells are tightly controlled by estrogen.
WNT/β-catenin directed metabolic choice uncouples lung-resident alveolar macrophage inflammatory activity from self-renewal
Authors: Zhu Bibo , Wu Yue , Huang Su , Zhang Ruixuan , Li Chaofan , Cheon In Su , Wang Min , Zhou Xian , Nguyen Quynh , Zeng Hu , Taketo M. Mark , Mack Matthias , Shapiro Virginia , Zhou Xiaobo , Goldrath Ananda , Kaplan Mark H , Sun Jie 
Published: January 2023

Abstract
Fetal-derived tissue-resident macrophages exhibit stem cell-like features of self-renewal in adulthood to maintain macrophage population during homeostasis and/or various insults. However, little is known about the cellular and molecular mechanisms modulating proliferative and inflammatory fate decisions of tissue-resident macrophages in vivo. Here, we show that WNT-β-catenin signaling inhibited lung-resident alveolar macrophage (AM) self-renewal, while simultaneously promoted AM inflammatory activities in vitro and in vivo during influenza virus infection. Mechanistically, WNT engagement facilitated the binding of β-catenin with HIF-1α over its conventional binding partner TCF-4. Such a binding choice led to the elevated macrophage inflammation in a glycolysis-dependent manner, while inhibited AM self-renewal by causing mitochondrial damage and impairing oxidative phosphorylation. Thus, AM self-renewal and inflammatory activity are uncoupled by WNT-β-catenin signaling through HIF-1α-mediated cellular metabolic choice. Importantly, we showed that AM with high HIF-1α activity had limited proliferative capacity and produced inflammatory cytokines, while AM with low HIF-1α activity were highly proliferative and expressed genes associated with tissue repair function in vivo during influenza virus infection. In accordance, we demonstrated that AM proliferation and repopulation were needed for optimal lung repair following the clearance of influenza virus in the respiratory tract. Our results have revealed key mechanisms modulating macrophage fate choice between progeny production versus inflammatory effector activity, and subsequent effects on tissue inflammation and repair.
Complement C3 deficiency exacerbates development of cardiovascular lesions in the LCWE-induced Kawasaki Disease Vasculitis
Authors: kocaturk begum , Lee Youngho , Moreira Debbie , Lane Malcolm , Shimada Kenichi , Rivas Magali Noval , Arditi Moshe 
Published: January 2023

Abstract

Background
Kawasaki disease (KD) is an acute febrile systemic vasculitis of childhood, mostly affecting the coronary arteries. A central feature of acute KD is the activation of the innate and adaptive immune systems. Serum complement component C3 is significantly increased in children during the acute stages of KD, and a polymorphism of a C type lectin, mannose binding lectin (MBL), has been associated with KD vasculitis and coronary artery lesions. However, the role of the complement pathway in KD vasculitis remains unclear.

Objective
Determine if the complement system contributes to KD pathogenesis in the Lactobacillus casei cell wall extract (LCWE)-mediated murine model of KD vasculitis.

Methods and Results
Serum levels of various complement proteins were elevated in LCWE-injected mice. We observed that the LCWE extract, rich in rhamnose and a TLR2 ligand, was able to bind both C3 and MBL in-vitro. Genetic deletion of C3 exacerbated LCWE-induced aortitis, coronary arteritis and abdominal aorta dilation and aneurysm. Furthermore, in-vivo blockade of C5 with a C5aR1 antagonist (PMX205) also increased these cardiovascular lesions in LCWE mice.

Conclusions
Blocking key components of the complement system, such as C3 and C5aR, significantly enhanced cardiovascular lesions in the LCWE-induced KD vasculitis mouse model. Thus, C3 or downstream activation fragments may play a protective role in the development of KD cardiovascular lesions. Whether this protection is due to complement mediated increased clearance of immune complexes or common carbohydrate pathogen molecules will need to be determined and may help our current understanding of the immunopathologic mechanisms of KD vasculitis. (Supported by NIH grant AI072726 to MA)
Regulation of RIG-I antiviral function by the RNA helicase DHX16 and unanchored polyubiquitin chains
Authors: Hage Adam , Bharaj Preeti , van Tol Sarah , Aguilera-Aguirre Leopoldo , Rajsbaum Ricardo 
Published: January 2023

Abstract
The type-I interferon (IFN-I) pathway mediates antiviral responses and is regulated to balance pathogen clearance while mitigating host damage. Our group recently showed that unanchored K48-linked poly-ubiquitin (K48 poly-ub) chains associate with the IKKɛ kinase to induce an optimal IFN-I mediated antiviral response. To identify other factors that may be regulated by unanchored poly-ub, we developed a novel method to isolate these chains from influenza A virus (IAV)-infected mouse lungs. Combining this approach with mass spectrometry analysis we identified DHX16, an RNA helicase previously known only as a pre-mRNA splicing factor. Next-Generation sequencing identified several IFN-stimulated genes whose expression was significantly downregulated in DHX16 knockdown cells. Consistent with this, in vitro and in vivo knockdown of DHX16 during IAV infection reduced IFN-I responses leading to increased IAV replication. DHX16-dependent IFN induction requires its intact RNA helicase motif and DHX16 ATPase activity is enhanced upon addition of unanchored K48 poly-ub in the presence of viral RNA, suggesting DHX16 first recognizes viral RNA and unanchored poly-ub regulate its activity. Furthermore, DHX16-induced IFN also requires RIG-I and this occurs in a RNA-dependent manner. Finally, we identified TRIM6 as the E3-Ub ligase that catalyzes the synthesis of unanchored K48 poly-Ub that positively regulate DHX16 activity. In conclusion, we uncovered a novel mechanism by which unanchored poly-Ub and DHX16 contribute to viral RNA recognition by RIG-I to induce an optimal IFN-I mediated antiviral response