bluuebunny/crossref_metadata_2025_split huggingface dataset:
Itaconate inhibits alternative activation of macrophages by targeting Janus Kinase 1
Authors: Runtsch Marah C , O’Neill Luke 
Published: January 2023

Abstract
In innate immune cells, TCA cycle components are not simply inert metabolites, but are key signaling molecules that can modulate inflammatory responses. Itaconate, an immunometabolite made by the enzyme aconitase decarboxylase (encoded by the gene Irg1), is highly upregulated in classically activated M1 macrophages and regulates immune responses by dampening inflammation. The role of itaconate in activation of alternative macrophage programs is of interest, as itaconate has recently been shown to be taken up by M2 macrophages. Here, we show that expression of Irg1 is specific to M1 macrophages and opposes regulators of IL-4 mediated alternative activation. Overexpression of Irg1 in murine M2 macrophages inhibited their program. Similarly, exogenous addition of a cell-permeable derivative of itaconate inhibited M2 gene expression and blocked activation of Stat6 and AKT in IL-4 activated macrophages. Itaconate-treated M2 macrophages also showed decreased oxidative phosphorylation, altogether suggesting that itaconate constrains IL-4-mediated alternative activation of macrophages. Mechanistically, this novel role of itaconate was not through previously reported pathways Nrf2 or Complex II (SDH), but rather via inhibition of the phosphorylation of Janus Kinase 1. We also show that an M2-specific microRNA, miR-378a, targets Irg1 to prevent itaconate production in these cells. Thus, we demonstrate that itaconate antagonizes M2 macrophage activation, suggesting a mechanism by which M1 macrophages inhibit alternative macrophage polarization. This may be useful in considering the therapeutic potential of itaconate as an inhibitor of M2 macrophages in such conditions as allergic asthma and fibrosis.
Targeted Deletion of CD11b+ Macrophage Subtypes alter the Acute Inflammatory Cytokine Response In Bone Healing
Authors: Cottrell Jessica , Hozain Sarah , Touma Danielle 
Published: January 2023

Abstract
Any immunological or inflammatory dysregulation can impair the bone healing process. Macrophages (MØ) are immune cells specialized for phagocytosis and assist in all stages of bone repair. MØs are often divided into two main subsets, MØ1, pro-inflammatory M1 macrophages and MØ2, anti-inflammatory or resolving M2 macrophages. Our preliminary data demonstrates that MØ1 to MØ2 polarization occurs following femur fracture during the first 7 days post-fracture and is associated with a specific cytokine expression profile over time. Other studies have demonstrated that dysregulated inflammation can impair fracture healing outcomes in normal mice. We hypothesize that targeted depletion of CD11b+ MØ cells will reduce the acute inflammatory response, alter the normal cytokine expression profile, and interfere with the bone healing response. Therefore, the bone marrow of mice depleted of CD11b+ MØ cells were compared to normal mice following femur fracture at days 0, 1, 2, and 4 using established methods. MØ subtypes were identified using flow cytometry and cytokine expression was quantified using Luminex. The data demonstrated that after fracture, the CD11b+ MØ depleted group had significantly less MØ1s, F480+/CD86+/MHC classII+/CD11b+ cells when compared to controls at all timepoints. MØ cytokine expression profiles were found to be altered in the control fractures when compared to the CD11b+ MØ depleted fractures. Our results demonstrate that MØ subsets contribute substantially to the signaling mechanisms that guide the acute inflammatory phase of bone healing. Proper modulation of macrophage polarization may be useful to develop novel treatment strategies to improve healing when the immune system or inflammation is dysregulated.
Forkhead box O 6 modulates immunological functions of Dendritic cells
Authors: Kim Mi Eun , Cho Jun Hwi , Lee Jun Sik 
Published: January 2023

Abstract
Forkhead box O (FoxO) is a transcription factor which is involved in cell cycle progression, cell survival and DNA-repair. Dendritic cells (DCs) are professional antigen-presenting cells which present the antigens to T lymphocytes and regulate the adaptive immunity. Previous studies indicated that FoxO1 and 3 are plays a critical role in DC maturation and DC-T cell interaction. FoxO6, a member of FoxO family, is less attended than other FoxO families, because limited expression region of FoxO6. Also, the effect of FoxO6 is still unknown. Here, we investigated the effect of FoxO6 in dendritic cells. Out data suggest that FoxO6 is expressed in murine dendritic cells. Moreover, phosphorylated FoxO6 is increased and acetylated FoxO6 is decreased during dendritic cell differentiation. We expect that FoxO6 has important role in DC differentiation and maturation, and will further investigate the functions and the mechanisms of FoxO6 on DC. And alteration of FoxO6 expression level had effect on DCs maturation.
[This work was supported by the Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education (NRF-2014R1A1A1008053), Korea.]
Analysis of regulatory elements in the HLA-A, HLA-B, and HLA-C genes provides insights into the specific role of each HLA in the immune system
Authors: Anderson Stephen , Li Hongchuan 
Published: January 2023

Abstract
We have conducted a detailed analysis of regulatory elements present in the upstream region of the HLA-A, HLA-B, and HLA-C genes. Significant differences in transcription factor-binding sites were identified in a tissue-specific promoter located 1.3 kb upstream, an enhancer element at −800 bp, and the core promoter region, that alter both the tissue specificity and expression level of the HLA genes. The upstream promoter has changed from macrophage-specificity in HLA-A to an unknown specificity in HLA-B, and it has gained NK specificity in HLA-C that is coupled with an elaborate post-transcriptional regulatory mechanism. The −800 enhancer region contains distinct arrays of transcription factor-binding sites in the HLA-A, HLA-B, and HLA-C genes. A comparison of the proximal promoter region of these three genes revealed multiple differences in key enhanceosome and cytokine-inducible elements, and the presence of additional trophoblast-specific elements in the HLA-C promoter. Furthermore, a comparison of HLA-C alleles reveals functional differences in transcription factor-binding sites that likely reflects allele-specific tuning of expression. A more complete understanding of the molecular evolution of regulatory elements between the HLA-A, HLA-B, and HLA-C genes will provide important clues with regard to the separate immunological functions of the three MHC class I genes present in humans.
Axl-mediated Akt phosphorylation leads to mTORC1 activation via NFk-B in renal mesangial cells
Authors: Shao Wenhai , Zhen Yuxuan 
Published: January 2023

Abstract
Proliferative glomerulonephritis (GN) is a critical condition in many forms of kidney diseases and characterized by the proliferation of mesangial cells with influx of inflammatory cells. Receptor tyrosine kinase Axl belongs to the TAM family, along with Mer and Tyro-3. Receptors from this family contribute to clearance of apoptotic cells and suppression of inflammation. Previously, we reported an important role of Axl-mediated mesangial proliferation in the anti-GBM induced mouse model of lupus nephritis. In this study, we investigated the signaling cascade induced by Axl activation in renal mesangial cells. We found that Axl activation led to the phosphorylation of mTORC1 complex, proceeded with the ribosomal protein S6 activation. Inhibition of NFκ-B activity diminished mTOR phosphorylation in mesangial cells, indicating that NFκ-B is a critical regulator for mTORC1 activation in the Axl/Akt pathway. Axl expression also participated in mesangial cell efferocytosis. Interestingly, mesangial efferocytosis is not mediated by Mer receptor tyrosine kinase, the canonical TAM family receptor facilitating apoptotic cell engulfment in macrophages. Taken together, data suggest that Axl mediated mTOR activation and apoptotic cell engulfment is renal mesangial cell specific, as those functions were not observed in similarly treated peritoneal macrophages.
Trib1 controls antiviral immunity by restraining CD4 and CD8 T cell effector responses during chronic infection
Authors: Rome Kelly S , Pear Warren S 
Published: January 2023

Abstract
During chronic infection, the magnitude of the antiviral T cell response is determined by the balance between T cell effector (TEFF) function and T cell exhaustion. While CD8 T cell exhaustion has been extensively characterized, how TEFF responses are regulated during chronic antigen exposure is less clear. We identify Tribbles Pseudokinase 1 (Trib1) as a central regulator of the TEFF response to chronic infection. We show that Trib1 expression is elevated in activated T cells and in human or mouse T cells following chronic infection. In chronically infected mice, T cell-specific deletion of Trib1 enhanced CD4 and CD8 TEFF expansion, persistence and function and reduced viral load. Mechanistically, we show that Trib1 functions as a negative regulator of signaling downstream of the T cell receptor (TCR), whereby Trib1 expression disrupts TCR signaling complexes. These data support a model of negative feedback regulation whereby Trib1 restrains TCR signaling and downstream function. Together, our work shows that Trib1 functions to restrain the magnitude and duration of the TEFF response, at least in part through the disruption of TCR signaling complexes, and reveals a new regulatory node downstream of TCR signaling that is critical during chronic infection. In light of growing interest in checkpoint blockade therapies that act to overcome exhaustion during chronic antigen exposure, our work reveals an important new avenue for enhancing the efficacy of current T cell reactivation strategies during chronic disease.
Smad signaling determines the fate of activated CTLs via multiple intersecting signaling pathways
Authors: Chandiran Karthik , Suarez-Ramirez Jenny E , Hu Yinghong , Kaech Susan , Cauley Linda S 
Published: January 2023

Abstract
Immune responses to an infection are controlled by various factors including antigens, co-stimulatory molecules and cytokines present in the tissue micro-environment. These factors modulate the differentiation of effector CD8 T cells and memory subsets. TGFβ plays a pivotal role in fate determination of activated CTLs. In TGFβ pathway, Smad proteins are critical for downstream signaling. Using transgenic animal models and pharmacological inhibitors, we investigate the role of TGFβ and Smad proteins in fate determination of activated CTLs. We identified that TGFβ and Smad proteins play important roles in regulating the expression of several homing receptors on effector CD8 T cells (KLRG1) and memory subsets (CD62L, S1PR1 and CD103). In addition, targeted-ablation of different Smad proteins alter the expression levels of different transcription factors that participate in fate determination, including Eomes and KLF2. We found that while Smad proteins regulate the gene expression in canonical TGFβ pathway, they also have TGFβ independent functions in determining the fate of activated CTLs. Particularly, we show that Smad4 is required for the expression of KLRG1 and acts as a suppressor of CD103, independent of TGFβ. This study reveals a novel role for Smad signaling cascade in guiding the fate decisions of activated CTLs and tissue localization via multiple intersecting signaling pathways.
The utilisation of clinically relevant Immunological research examples for undergraduate Medical sciences education
Authors: Sika-Paotonu Dianne , Gu Vivian , Williams Grace , Pinfold Esther , Whyte Julia , Motu Lakin , Anitelea Toni , Yuhoi Jessica , Laing Bridie 
Published: January 2023

Abstract
Immunology education supports the clinical understanding and contextualisation of important cellular processes and mechanisms. To support effective learning and teaching within undergraduate Medical sciences courses, the integration of clinically relevant Immunological course elements and related research teaching examples are needed. The aim was to incorporate a clinically relevant Immunological based research example, presented in class to 4th year undergraduate Medical sciences students. A partial focus of this work was also to help raise awareness of current health issues and priorities facing Māori and Pacific population groups living in New Zealand (NZ) and the Pacific Region. The autoimmune condition known as Acute Rheumatic Fever (ARF), caused by untreated Group A Streptococcal (GAS) infection of the throat (and skin) was discussed in class within the context of regular administration of Benzathine Penicillin G (BPG) that prevents subsequent ARF attacks. Untreated ARF can trigger permanent cardiac damage called Rheumatic Heart Disease (RHD). Rates of ARF in NZ, Australia and the Pacific Region are among the highest in the world, particularly within Māori, Pacific and Indigenous Aboriginal population groups. Student feedback indicated that in-depth interest and understanding was demonstrated using the ARF and RHD Immunological based teaching example. In addition, students were motivated to engage in Summer Scholarship placements focused on the ARF/RHD and BPG based research work. These observations highlight the successful incorporation of a clinically relevant Immunological teaching example that supported the learning and application of scientific research content for undergraduate Medical students.
Characterizing the BCG induced T cell independent mechanisms for defense against Mycobacterium tuberculosis
Authors: Bickett Thomas , Creissen Elizabeth , Angulo Fabiola Silva , Izzo Antonio , Izzo Linda , Izzo Angelo A 
Published: January 2023

Abstract
Mycobacterium bovis Bacille Calmette Guérin (BCG) is a potent immune stimulator that activates innate and adaptive immunity. In the C57BL/6 mouse model of tuberculosis, BCG stimulated immunity causes a significant reduction of M. tuberculosis burden after pulmonary infection. The majority of work has focused on BCG induced T cell immunity as CD4+ T cells play a significant role in protection against tuberculosis. We hypothesized that BCG also induced a T cell independent mechanism that was sufficient to significantly restrict mycobacterial growth. BCG robustly activates innate immunity and our preliminary experiments showed that BCG induced a significant reduction in colony forming units (CFU) in the lungs of mice vaccinated 7 days before pulmonary infection. Our studies indicated that although BCG was administered through subcutaneous inoculation, increased numbers of Ly6C+ monocytes were observed in the lungs within 7 days. Selective depletion also determined that neutrophils played a role in priming innate immunity. Others have identified a role for innate immunity during BCG vaccination termed trained innate immunity. However, our results suggested that at day 7 post BCG vaccination trained innate immunity did not cause the CFU reduction, as the NOD2 receptor or NK cell activation were not absolute requirements, despite being linked to trained immunity. Furthermore, in vivo killing of mycobacterium was dependent on BCG being viable and was monocyte derived, highlighting a novel mechanism. Taken together our data suggest that an early innate mechanism induced by viable BCG is responsible for reducing the mycobacterial burden and precedes trained innate immunity.
The Ca2+ sensor STIM1 regulates the type I interferon response by retaining the signaling adaptor STING at the endoplasmic reticulum
Authors: WOO JIN SEOK , Srikanth Sonal , Wu Beibei , El-Sherbiny Yasser M , Leung Jennifer , Chupradit Koollawat , Rice Laura , Seo Gil Ju , Calmettes Guillaume , Ramakrishna Chandran , Cantin Edouard , An Dong Sung , Sun Ren , Wu Ting-Ting , Jung Jae U. , Savic Sinisa , Gwack Yousang 
Published: January 2023

Abstract
Stimulator of interferon genes (STING) is an endoplasmic reticulum (ER) signaling adaptor that is essential for the type I interferon response to DNA pathogens. Aberrant activation of STING is linked to the pathology of autoimmune and autoinflammatory diseases. The rate-limiting step for the activation of STING is its translocation from the ER to the ER-Golgi intermediate compartment. Here, we found that deficiency in the Ca2+ sensor stromal interaction molecule 1 (STIM1) caused spontaneous activation of STING and enhanced expression of type I interferons under resting conditions in mice and a patient with combined immunodeficiency. Mechanistically, STIM1 associated with STING to retain it in the ER membrane, and coexpression of full-length STIM1 or a STING-interacting fragment of STIM1 suppressed the function of dominant STING mutants that cause autoinflammatory diseases. Furthermore, deficiency in STIM1 strongly enhanced the expression of type I interferons after viral infection and prevented the lethality of infection with a DNA virus in vivo. This work delineates a STIM1-STING circuit that maintains the resting state of the STING pathway.
Lysophosphatidylcholine activates caspase-1 by bringing about release of ATP and sensitization of purinergic receptor
Authors: Ismaeel Sana , Qadri Ayub 
Published: January 2023

Abstract
Lysophosphatidylcholine (LPC) is one of the major damage associated molecular patterns (DAMP) released during inflammation and infection. It generates inflammatory responses from different cell types including macrophages and neuronal cells, and causes demyelination in experimental models of neuroinflammation. LPC activates cellular responses through GPCR dependent and independent signaling. Recently, it has been shown to bring about release of IL-1β through inflammasome-mediated activation of caspase-1. However, the exact mechanism by which LPC stimulates inflammasomes has not been investigated. In this study, we show that LPC triggers release of ATP from cells and activates purinergic signaling, which produces cytotoxicity and caspase-1 – dependent production of IL-1β. LPC activates caspase-1 in a G-αi independent manner. Treatment with apyrase or inhibition of P2X7 receptor reduces LPC - mediated release of LDH and IL-1β. These results identify induction of ATP-release as the critical first trigger by which LPC brings about caspase-1 – dependent inflammatory response.
Novel monoclonal antibodies for the detection of human TLR9
Authors: Acuff Nicole V , Oida Takatoku , Divekar Anagha A , Yang Xifeng 
Published: January 2023

Abstract
Human TLR9 (CD289) is a well characterized mediator of antiviral immunity. TLR9 is primarily activated by unmethylated CpG sequences leading to the production of type I interferons and other inflammatory cytokines. Recently, changes in TLR9 expression in cancer have also been reported. Here we describe novel monocloncal antibodies for the detection of human TLR9 by flow cytometry. These clones recognize intracellular TLR9 in B cells and plasmacytoid dendritic cells (pDCs), as well as on HEK293 cells transfected with human TLR9, and are compatible with multiple fixation and permeabilization buffers. We also show surface expression of TLR9 on pDCs, which is reported to be upregulated following stimulation. In response to CpG-B stimulation, two clones enhance and inhibit TLR9 signaling in a concentration dependent manner leading to alterations in cytokine secretion. Reported here are multiple human TLR9 clones with greater specificity than other commercially available clones.
Induction of innate antiviral immunity through a novel pattern recognition receptor, the RNA helicase DHX16, is regulated by unanchored K48-linked poly-ubiquitin chains
Authors: Hage Adam , Bharaj Preeti , 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. Unanchored K48-linked poly-ubiquitin (K48 poly-ub) chains, which associate with targets through non-covalent interactions, have been shown by our group to be a critical regulatory signal in IKKe kinase-mediated antiviral immunity. To identify other components requiring unanchored poly-ub, we developed a novel method to isolate these chains from influenza virus (IAV)-infected mouse lungs. Using this approach combined with mass spectrometry analysis we identified DHX16, an RNA helicase and pre-mRNA splicing component. The role of DHX16 in innate immunity and regulation of its activity have not been described. We found that during IAV infection, the levels of unanchored K48 poly-ub that associate with DHX16 are significantly increased and these DHX16-interacting chains are synthetized by the E3-ubiquitin ligase TRIM6, which we have previously shown to be critical in IFN-I and antiviral responses. Next-Generation sequencing identified a number of IFN-stimulated genes whose expression was significantly downregulated in DHX16 knockdown cells. Consistent with this, overexpression of DHX16 induced IRF3 phosphorylation, which can be further enhanced upon IAV infection. Furthermore, the ATPase activity of DHX16 is enhanced upon addition of unanchored K48 poly-ub only in the presence of viral RNA suggesting DHX16 first recognizes viral RNA and unanchored poly-ub regulate its activity. Together these data suggest DHX16 acts as a novel pattern recognition receptor involved in the IFN-I pathway and its activity is regulated by unanchored K48 poly-ub.
NME4 regulates TLR3 activation and type I IFN production through autophagy-dependent TRAF6 degradation
Authors: Sun Bing , Zhao Xin Hao , Zhang Rong Hua 
Published: January 2023

Abstract
Nucleoside diphosphate kinase (NDPK)/Nm23 family proteins play multiple roles in energy metabolism, proliferation, differentiation, inflammatory responses and tumour invasion. Among these proteins, only NDPK-D (NME4) is located in the mitochondrial luminal space and the inner mitochondrial membrane. NME4 shows high affinity for cardiolipin (CL) and facilitates its redistribution to the outer mitochondrial membrane (OMM), which leads to mitophagy and inflammatory regulation. Here, we demonstrate that NME4 can regulate the type I interferon pathway by modulating the TLR3-TRAF6-IFN axis. NME4 deficiency promotes the degradation of TRAF6 and impairs the phosphorylation of p65 and p38. Overexpression of NME4 significantly upregulates the interferon production induced by a TLR3 ligand. However, when the NEM4 signal peptide for mitochondrial localization is deleted, the regulation of IFN production is abolished. We demonstrate that NME4 deficiency-mediated suppression of interferon production is rescued when ATG5 is knocked down following TLR3 stimulation, suggesting that NME4 is able to regulate interferon production through the autophagy pathway. Furthermore, influenza A virus-infected NME4 knockout mice showed higher mortality, which was associated with reduced interferon production compared to that in wild-type mice. Taken together, our results indicate that NME4 plays an important role in regulating TLR3-mediated interferon production.