bluuebunny/crossref_metadata_2025_split huggingface dataset:
Immature myeloid/myeloid-suppressor cells and myeloid cell necroptosis mediate lethal pulmonary tularemia
Authors: Periasamy Sivakumar , Avram Dorina , MacNamara Katherine C , Sellati Timothy J , Harton Jonathan A 
Published: January 2023

Abstract
Inhalation of Francisella tularensis (Ft) causes acute and fatal pneumonia. The lung cytokine milieu favors exponential Ft replication, but mechanisms underlying acute pathogenesis and death remain unknown. Evaluation of the sequential and systemic host immune response in pulmonary tularemia reveals that an overt innate cellular response to Ft, not bacterial burden per se, drives tissue pathology and host mortality. Lethal infection with Ft elicits medullary and extra-medullary myelopoiesis supporting recruitment of large numbers of immature myeloid cells and MDSC to the lungs. These cells fail to mature, but subsequently die leading to necrotic lung damage, loss of pulmonary function, and host death. Ensuing tissue damage and host mortality is Necrostatin sensitive and depletion of dying immature Ly6G+ cells is beneficial, implicating a contribution of necroptotic cell death in tularemia pathogenesis. Accelerated recruitment of immature myeloid cells and/or myeloid cell death may account for the rapid mortality seen with a virulent strain of Ft SchuS4. In contrast, during sub-lethal infection with Ft LVS the pulmonary cellular response is characterized by a predominance of mature neutrophils and monocytes required for protection, suggesting a required threshold for lethal bacterial infection. Further, eliciting a mature phagocyte response provides transient, but dramatic, innate protection against Ft SchuS4. This study reveals that the nature of the innate myeloid cell response may be the primary determinant of host mortality versus survival following Francisella infection
ER stress-induced IRE1α activation obliterates endotoxin tolerance through modulation of cytokine production via GSK-3βand XBP-1
Authors: Chung Hun Taeg , Joe Yeonsoo , Kim Sena , Kim Hyo Jeong , Park Se-ung , Chen Yingqing , Park Jeongmin , Park Hyeok-Jun 
Published: January 2023

Abstract
Endotoxin tolerance occurs in the late phase of sepsis in order to protect cells from the early hyper-inflammatory response. However, as it induces immunosuppressive environment, septic patients in their late phase are suffering from secondary infections, particularly the bacterial pneumonia. Here we show that induction of ER stress leads to activation of GSK-3β and XBP-1 in an IRE1α-mediated manner, which in turn obliterates endotoxin tolerance. Consequently, from the lung of septic host infected with P. aeruginosa, symptoms of pneumonia have been improved and the bacteria cleared. Thus, for septic patients, determination of immune status would be helpful in guiding the selective usage of appropriate immune modulation, in that ER stress can be a novel therapeutic maneuver, restoring the immune response in patients with endotoxin tolerance.
Insights into the development and function of a dendritic cell-like neutrophil in a model of fungal pneumonia
Authors: Fites J Scott , Klein Bruce 
Published: January 2023

Abstract
Phenotypic plasticity in neutrophils has been frequently observed under inflammatory scenarios in both humans and mice. One of the phenotypically converted neutrophil populations has properties of both neutrophils and dendritic cells previously defined as a neutrophil-DC hybrid (PMN-DC). While a modicum of evidence suggests how this morphological conversion occurs, the role that PMN-DCs play in natural settings of infection and inflammation remains speculative. I observe the emergence of PMN-DCs in a fungal pneumonia model of Blastomyces dermatidis infection, which drives strong recruitment of neutrophils to the lung. Although PMN-DCs, as previously described, comprise a small proportion of neutrophils, the pyogranulomatous nature of Blastomyces infection promotes the accumulation of a large number of PMN-DCs allowing interrogation of this poorly understood cell type in the context of an infection. Granulocyte-macrophage colony-stimulating factor (GM-CSF) drives neutrophil-to-DC conversion in vitro but has an undefined role in PMN-DC development in vivo. Inactivation and neutralization of GM-CSF during fungal challenge had no effect on the development of neutrophil-DCs suggesting a non-requisite role for GM-CSF. A functional role for PMN-DCs during primary infection was also observed during Blastomyces infection. PMN-DCs not only kill yeast in vivo, but they associate with and kill yeast far out of proportion to their population size. These studies in the Blastomyces infection model indicate that GM-CSF plays a non-requisite role in PMN-DCs emergence and that PMN-DCs play an important role in microbial clearance.
‘Hypoxia reprograms human macrophages towards a proinflammatory direction’
Authors: Varesio Luigi , Raggi Federica , Pelassa Simone , Pierobon Daniele , Cangelosi Davide , Giovarelli Mirella , Bosco Maria Carla 
Published: January 2023

Abstract
Mononuclear phagocytes are recruited from the circulation as primary monocytes to sites of infection, inflammation, and tumor growth, where they undergo terminal differentiation into macrophages. Macrophages can be polarized into classically activated macrophages (M1) or alternatively activated macrophages (M2) which are characterized by a proinflammatory or an anti-inflammatory phenotype, respectively. M1 and M2 polarization is regulated by microenvironment factors. A common feature of pathologic situations is represented by hypoxia. Little is known about the impact of hypoxia on M1/M2 polarization. To address this issue, M1 (CD80+) and M2 (CD206+) macrophages were generated by culturing human monocytes with LPS or IL4 for 24h under normoxia (20%O2) or hypoxia (1%O2). We show that hypoxia amplifies the proinflammatory state of M1 macrophages and reprograms M2 macrophages towards a proinflammatory direction by increasing the production of inflammatory and proangiogenic cytokines/chemokines. The hypoxic pathologic microenvironment can tune the expression of immunoregulatory signaling receptors, whose deregulated expression may result in amplification of inflammation or establishment of immune escape situations. We demonstrate that hypoxia strongly upregulates the expression of one of such receptors, TREM -1, in M1 and M2 macrophages. Engagement of TREM-1 by agonist Ab triggers further production of M1-type cytokines/chemokines in both populations. These results suggest the role of the hypoxic environment present at pathologic sites in skewing macrophages towards a M1-like proinflammatory phenotype by inducing TREM-1, highlighting the potential of targeting TREM-1 in inflammatory disorders and in tumors.
Myeloid cell-specific Sirt1 knockout impairs innate immune responses against intracellular bacteria infection
Authors: Lee Sang-Myeong , Seo Dong-Won , Kang Kyung Won 
Published: January 2023

Abstract
It has been well documented that SIRT1, a member of Class III histone deacetylase directly regulates various functions of macrophages. However, most of studies had focused on its’ role in metabolic diseases although the primary role of macrophages is to remove pathogens as a major component of innate immune responses. Especially, the role of Sirt1 in intracellular bacterial infection is widely unknown. In the present study, we investigated the innate immune response against Listeria monocytogenes (LM) infection in wild type (WT) or SIRT knockout (KO) mice. In the absence of Sirt1, bacterial clearance and secretion of pro-inflammatory cytokines including TNF-α and IL-6 were decreased after LM infection in bone marrow derived macrophages (BMDM). When mice were infected with LM, Sirt1 KO mice were significantly more susceptible to LM infection and showed 100% mortality while less than 40% of WT mice were died. Similarly to in vitro experiments, bacteria clearance and cytokine production were remarkably lower in Sirt1 KO mice compared to WT mice infected with LM. In conclusion, the present study found out that deletion of SIRT1 gene in myeloid cells impairs innate immune system, leading to increased susceptibility due to bacteria accumulation and reduced pro-inflammatory cytokines. These results suggest that SIRT might be a key regulator for innate immune response against intracellular bacterial infection.
Lipopolysaccharide downregulates FcγRIIb via MARCH3-mediated ubiquitination
Authors: Butchar Jonathan P , Fatehchand Kavin , Ren Li , Elavazhagan Saranya , Fang Huiqing , Mo Xiaokui , Vasilakos John P , Dietsch Gregory N , Hershberg Robert M , Tridandapani Susheela 
Published: January 2023

Abstract
Monocytes and macrophages are critical for the effectiveness of monoclonal antibody therapy. Cellular responses to antibody-coated targets are largely mediated by Fcγ receptors (FcγR), which cluster and become activated upon binding immune complexes. FcγRIIb is an inhibitory FcγR that negatively regulates these responses, so deletion or down-regulation of this receptor may substantially enhance the outcome of antibody therapy.
Toll-like receptor (TLR) agonists are being used and tested as immune-stimulatory agents for cancer. We screened a panel of TLR agonists to test their effect on FcγRIIb expression and found significant receptor downregulation with TLR4 and TLR8 agonists. We selected the TLR4 agonist lipopolysaccharide (LPS) for further examination and found that it led to the ubiquitination of FcγRIIb protein. In a search of our microarray database of monocytes treated with a TLR7/8 agonist (in which FcγRIIb was down-regulated), we found that membrane-associated ring finger (C3HC4) 3 (MARCH3), an E3 ubiquitin ligase, was significantly upregulated. We next tested whether this same E3 ligase was also upregulated with LPS treatment and whether it was required for LPS-mediated FcγRIIb downregulation. Results showed that LPS significantly increased MARCH3 expression and that siRNA against MARCH3 prevented the LPS-mediated decrease in FcγRIIb. These data suggest that LPS effects the downregulation of FcγRIIb through ubiquitination and that this is mediated by the E3 ligase MARCH3.
microRNA-142 is critical for peripheral NK cell homeostasis and function.
Authors: Berrien-Elliott Melissa M , Sun Yaping , Sullivan Ryan , Ireland Aaron , Trissal Maria , Wong Terrance , Leong Jeffery , Wagner Julia , Jewell Brea , Schappe Timothy , Abdel-Latif Sara , Link Daniel , Reddy Pavin , Fehniger Todd A. 
Published: January 2023

Abstract
MicroRNAs (miRNA) are small, non-coding RNAs that post-transcriptionally regulate the translation of their targeted mRNAs. Next-generation small RNA sequencing has identified a number of mature miRNAs that are highly expressed in murine NK cells, including miR-142. We hypothesized that miR-142-5p/3p regulated NK cell development, survival, or functionality, and investigated this concept by examining the NK cell compartment in miR-142−/− mice. Despite having normal NK precursor and NK cell frequencies and absolute numbers in the bone marrow (BM), miR-142−/− mice exhibited a marked reduction of NK cells in the spleen (5-fold), blood (5-fold), lymph node (10-fold), and liver (2-fold) compared to controls. The NK deficiency observed in miR-142−/− mice was not due to blocked maturation, as the frequencies of CD27/CD11b stage II, III, and IV NK cells were similar between wild-type and miR-142−/− mice. However, the absolute numbers of each stage were reduced in miR-142−/−, confirming that miR-142−/− mice display a global loss of NK cells in the periphery that is independent of NK cell maturation. Mixed BM chimera studies support a cell-intrinsic role for miR-142 in NK cell peripheral homeostasis. Furthermore, miR-142−/−NK cells do not signal through their IL-12, IL-15, and IL-18 cytokine receptors and thus fail to produce IFN-γ in response to cytokine stimulation thereby limiting their effector functions. miR-142−/− NK cells have a dramatically altered integrin expression profile compared to wild-type, which we hypothesize leads a failure of miR-142−/− NK cells to progress properly through the BM niche, resulting in the loss of NK cells in the periphery. Thus, miR-142 is required for normal NK cell peripheral homeostasis and function.
Dysregulation of immune response to enteric bacteria triggers the development of spontaneous experimental autoimmune encephalomyelitis
Authors: Yadav Sudhir Kumar , Ito Naoko , Mindur John E , Mathay Martin , Dhib-Jalbut Suhayl , Ito Kouichi 
Published: January 2023

Abstract
Multiple sclerosis (MS) is an autoimmune disease against the central nervous system (CNS). Although the etiology of MS is still unknown, breakage of peripheral immune tolerance to CNS antigens is believed to be an initial event of CNS autoimmune diseases. It has been indicated that gut microbiota is an important environmental risk factor in MS/EAE pathogenesis; however, the exact mechanism for pathogenesis has not been elucidated.
To examine how the immune tolerance to myelin basic protein (MBP) is broken, we created a humanized transgenic (Tg) mice that express MS-associated HLA-DR2a and MBP-specific TCR (3A6 TCR) genes isolated from an MS patient. The 3A6/DR2a Tg mice develop EAE spontaneously, and antibiotic treatment, which can reduce the population of commensal bacteria, was found to abolish the development of spontaneous EAE. Since fecal IgM is a marker of expansion of enteric bacteria, we examined the association of fecal IgM with spontaneous EAE development. Interestingly, raised levels of fecal IgM and expansion of enteric bacteria were associated with the development of spontaneous EAE, and a massive infiltration of MBP-specific Tg T cells and neutrophils, along with complement deposits, were detected in the colon of spontaneous EAE mice. Furthermore, MBP-specific GM-CSF+ Th1 and Th17 cells were expanding in the colon but not in the small intestine, and CNS-homing integrin, α4β1, was highly up-regulated in the MBP-specific T cells in the mesenteric lymph nodes in the spontaneous EAE mice.
These data suggest that enteric bacteria-mediated dysregulation of gut immunity may be involved in the initiation and progression of CNS-autoimmune diseases.
Identifying T cell antigens in sarcoidosis
Authors: Mitchell Angela M , Falta Michael T , Tinega Alex N , Grunewald Johan , Pinilla Clemencia , Fontenot Andrew P 
Published: January 2023

Abstract
Sarcoidosis is a multisystem disorder which most commonly affects the lungs and involves the accumulation of CD4+ T cells at the sites of disease. The etiology of the disease is unknown, and the lack of a known antigen has hindered the study of disease pathogenesis. However, there is considerable evidence that CD4+ T cells are involved in the initiation and perpetuation of sarcoidosis. Previous work by our lab and others has demonstrated that particular T cell clones within the bronchoalveolar lavage (BAL) have been preferentially expanded in patients with sarcoidosis. These oligoclonal T cell populations accumulate within the lung and disappear with disease resolution. Furthermore, correlations have been observed between the expansions of CD4+T cells expressing the T cell receptor (TCR) α-chain variable (V) region Vα2.3 and the presence of the HLA-DRB1*0301 (DR3) allele in certain patient populations. Preliminary data suggest that cells within the BAL expressing TCRs utilizing Vα2.3, Vβ5.1, and Vβ5.3 are preferentially expanded before and after ex-vivo stimulation with IL-2. We hypothesize that sarcoidosis-specific CD4+ T cells accumulate and expand in the lungs of sarcoidosis patients in response to a specific antigen. To determine whether these expanded CD4+T cell clones play a pathogenic role in disease progression, as well as to address their antigen specificity, the TCRs of these clones have been characterized, and a combinatorial peptide library has been screened to identify candidate antigens that stimulate these clones. These unbiased data will provide clues to the disease-initiating antigens that drive sarcoidosis in a subset of patients and will lead to an extension of our findings to a larger disease cohort.
Mitochondrial bioenergetics of immune cells in Type 1 diabetes
Authors: McDowell Ruth E , Tse Hubert 
Published: January 2023

Abstract
Mitochondrial (mito) bioenergetics of circulating cells change as a function of disease in Alzheimer’s, fibromyalgia, cancer, and Type 2 diabetes. We are exploring the use of mito-bioenergetics as a biomarker of Type 1 diabetes (T1D) progression and immune cell activation. T1D is a polygenic autoimmune disease in which an inflammatory leukocytic infiltrate into pancreatic islets results in destruction of insulin-producing β-cells. Autoantibody synthesis is currently used as a biomarker, but is a poor predictor of T1D since the majority of β-cells are destroyed prior to autoantibody seroconversion. We hypothesize that T1D is a chronic inflammatory disease in which conditions of oxidative stress will diminish the mitochondrial reserve capacity of immune cells and provide a surrogate marker for T1D. We compared mito-bioenergetics of murine immune cells derived from the spleen, pancreatic lymph node and bone marrow between diabetic and pre-diabetic Non-Obese Diabetic (NOD) mice. We show that mitochondrial reserve capacity is reduced in circulating CD4+ T cells from diabetic mice, but not in pre-diabetic mice during T1D progression. To explore the role of mitochondrial oxidative stress on diabetogenic CD4+ T cell effector responses, we used mito-TEMPO to scavenge mitochondrial reactive oxygen species (mROS). Mito-TEMPO reduced IFNγ synthesis in a primary recall assay by 0.24-fold and the combination of mito and cytosolic TEMPO increased Treg-associated IL-2 by 2.5-fold, suggesting that mROS have a causal role in modulating T cell effector responses critical for T1D pathology. We plan to perform human translational studies on mito-bioenergetics of PBMCs from recent onset T1D patients and further dissect the role of mROS on T1D.
Trogocytosis-Mediated Signaling Drives GATA-3 and IL-4 Expression in CD4+ T cells
Authors: Wetzel Scott A , Reed Jim 
Published: January 2023

Abstract
Membrane and membrane-associated proteins are transferred directly from APCs to recipient T cells at the immunological synapse in a process termed trogocytosis. Trogocytosis regularly occurs during CD4 T cell activation, however, the biological significance of these APC-derived molecules on the T cell remains unclear. We previously have shown that trogocytosed molecules drive sustained intracellular TCR signaling (elevated phospho-ZAP-70, phospho-Erk 1/2 and total phospho-tyrosine) after removal of APC leading to preferential survival in culture. Using murine fibroblasts expressing GFP-tagged I-Ek with covalently attached antigenic moth cytochrome c (88–103) along with surface biotinyated APCs, we expanded upon these data to assess whether this sustained signaling influences the effector functions of trogocytosis positive (trog+) CD4 T cells. Using non-polarized in vitro primed CD4+ T cell we observed that the trog+CD4 T cells have significantly elevated GATA3 and IL-4 production and decreased IFNγ, consistent with a TH2-like phenotype. The increase in GATA3 and IL-4 is observable 24 hours post trogocytosis and their expression levels continue to increase during a three day in vitro culture. These findings suggest that the sustained signaling associated with trogocytosed molecules in trog+ CD4 T cells may lead to effector phenotype differentiation and to sustained cytokine production, which has the potential to greatly influence adaptive immune responses.
Costimulatory pathways mediating T-dependent germinal center responses: distinct cellular requirements for CD40 and B7 costimulation
Authors: Watanabe Masashi , Fujihara Chiharu , Jeffrey Chiang Y , Bhatia Sumeena , Hodes Richard J 
Published: January 2023

Abstract
T cell-dependent (TD) germinal center (GC) and antibody responses require coordinated interactions of T cells with B cells and antigen-presenting dendritic cells (DCs). Although B7 and CD40 costimulatory pathways are critical for these responses, a comprehensive analysis of cell type-specific pathways has been hindered by the absence of models for conditional expression of B7 or CD40. Here we report generation of conditional knockout mice for both B7 and CD40, and the use of these lines together with conditional MHC class II (MHCII) knockouts and bone marrow chimeric strategies, to analyze pathways involved in TD GC and antibody responses. Our results indicate that MHCII-restricted recognition of both DCs and B cells is necessary for generation of antigen-specific TFH cells, GC B cells, and antibody response. Notably, the requirements for expression of B7 and CD40 were distinct, with B7 expression required on DCs but not on B cells, while CD40 was required on B cells but not DCs for generation of TFH cells, antigen-specific GC B cells, and antigen-specific class-switched antibody responses. These findings identify requirements for cell and costimulatory interactions in TD GC and antibody responses and support a unique model in which major costimulatory pathways function through interaction of T cells with distinct cell populations.
Helper T cells are required for the development of IgM memory cells, but not IgM bone marrow plasmablasts
Authors: Papillion Amber M , Kenderes Kevin , Winslow Gary 
Published: January 2023

Abstract
The processes and factors that regulate B cell fate decisions during IgM memory cell development and differentiation are unknown, and may differ from those required by canonical memory cells. In our experimental model of Ehrlichia muris infection, we have characterized two long-lived B cell populations: IgM memory cells, and IgM bone marrow (BM) antibody secreting cells (ASCs). The IgM+ memory B cells are required for recall IgG responses, while the BM ASCs produce antigen-specific IgM responsible for maintaining long-term immunity. Both populations are derived from an early AID-expressing CD4 T cell-independent splenic CD11c+ plasmablast population. Because abundant T follicular helper cells are generated in the spleen during early infection, we investigated whether T cell help regulates B cell fate. Infection of MHC class II-deficient mice revealed that the IgM+ memory B cells required CD4+ T cell help, while the IgM+ BM ASCs did not. Moreover, IgM memory cell transfer studies indicated that T cell help was required for the generation of IgM+ memory cells, but not for the generation of BM ASCs. On the basis of these observations, we propose that T cells drive B cell fate: developing spleen plasmablasts that receive T cell signals mature to become IgM memory cells, while cells that do not receive these signals follow a default pathway to become long-lived IgM BM ASCs.