bluuebunny/crossref_metadata_2025_split huggingface dataset:
Uncovering the mechanism of E1A antagonism of the cGAS-STING pathway
Authors: Burleigh Katelyn , Stetson Daniel B 
Published: January 2023

Abstract
The cGAS-STING pathway is critical for antiviral defense. Cytosolic DNA is detected by cGAS, which synthesizes the second messenger cGAMP that activates the signaling adaptor STING. Like the RNA sensing pathway, the cGAS-STING pathway converges on kinase TBK-1, which phosphorylates IRF-3, allowing it to translocate to the nucleus to induce production of type I interferons. Many viruses encode inhibitors of this pathway to avoid the ensuing antiviral state. Previously, we discovered that oncoproteins E7 and E1A encoded by human papillomavirus and adenovirus, respectively, specifically block the cGAS-STING pathway and that these proteins bind to STING. However, the mechanism underlying the antagonism of the cGAS-STING pathway is unknown. To dissect the mechanism for E1A, we used HEK 293 cells, which express E1A, to assess known events in the pathway: TBK-1 and IRF-3 phosphorylation, IRF-3 dimerization and IRF-3 nuclear translocation. Consistent with a specific block in the DNA-activated interferon response in HEK 293 cells, we found that IRF-3 dimerization and nuclear translocation were prevented in response to DNA, but not to RNA stimulation. Surprisingly, we found that early events were intact in response to DNA, including robust phosphorylation of IRF-3 on serine 386, which is required for dimerization. However, phosphorylation of serine 396, an event with unclear importance for IRF-3 activation, was impaired after DNA stimulation. This reveals that E1A blocks a potentially unappreciated late step in the pathway, preventing complete IRF-3 phosphorylation and subsequent dimerization. Ongoing work will address the temporal and spatial regulation of this novel step in STING-dependent IRF-3 activation and its antagonism by E1A.
MyD88-associated Toll-like receptor ligands prime macrophage metabolism for infection
Authors: Fensterheim Benjamin , Bohannon Julia , Guo Yin , Sherwood Edward 
Published: January 2023

Abstract
Toll-like receptor (TLR) ligands protect mice against an upcoming infection if administered prophylactically, however the mechanism of protection remains undefined. Here, we probed how TLR ligands alter the metabolic response of macrophages to lipopolysaccharide (LPS) challenge or infection. Wild type (WT), MyD88 knockout (KO), and TRIF KO murine bone marrow-derived macrophages (BMDMs) were pretreated with LPS, monophosphoryl lipid A (MPLA), CpG DNA, or poly(I:C), and, after a washout period, challenged with LPS. Additionally, WT mice were treated with TLR ligands and infected with intraperitoneal P. aeruginosa 3 days after priming. We found that all ligands that activate MyD88, including LPS, MPLA, and CpG DNA, primed macrophages to have an augmented glycolytic response to LPS challenge, whereas TRIF-specific poly(I:C) did not. Moreover, MyD88 was essential for this augmented glycolytic response, whereas TRIF was dispensable. LPS, MPLA, and CpG DNA significantly improved clearance and survival from a P. aeruginosa intraperitoneal infection, whereas poly(I:C) did not. In conclusion, TLR ligands prime the macrophage metabolic response to LPS via MyD88, while having variable effects on pro-inflammatory cytokine responses. Finally, MyD88-specific TLR ligands, but not TRIF-specific TLR ligands, improve the host resistance to infection.
CLEC18 family are novel C-type lectins with differential binding specificity to glycans and TLR ligands
Authors: Hsieh Shie-Liang 
Published: January 2023

Abstract
The human C-type lectin 18 (clec18) gene cluster, which contains clec18a, clec18b and clec18c three loci, is located in human chromosome 16q22. Even though the amino acid sequences of CLEC18A, CLEC18B, and CLEC18C are almost identical, several amino acid residues located in the C-type lectin-like domain (CTLD) and the Sperm-Coating Protein/Tpx-1/Ag5/PR-1/Sc7 (SCP/TAPS) domain, also known as the cysteine-rich secretory proteins/antigen 5/pathogenesis-related 1 proteins (CAP) domain, are distinct from each other. Genotyping by real-time PCR and sequencing further shows the presence of multiple alleles in clec18a/b/c loci. Flow cytometry analysis demonstrates that CLEC18 (CLEC18A, B and C) are expressed abundantly in human peripheral blood cells. Moreover, CLEC18 expression is further upregulated when monocytes differentiate into macrophages and dendritic cells (DCs). Immunofluorescence staining reveals that CLEC18 are localized in the endoplasmic reticulum (ER), Golgi apparatus, and endosome. Interestingly, CLEC18 are also detectable in human sera and culture supernatants from primary cells and 293T cells overexpressing CLEC18. Moreover, CLEC18 bind polysaccharide in Ca2+–independent manner, and the amino acid residues S/R339 and D/N421 in CTLD domain contribute to their differential binding abilities to polysaccharides isolated from Ganoderma lucidum (GLPS-F3). The S339 (CLEC18A) and R339 (CLEC18A-1) displayed differential binding affinity to TLR ligands. Their roles to determine host responses to virus infection are under intensive investigation now.
RIG-I-Like Receptors control unique innate immune responses following West Nile Virus infection
Authors: Stone Amy EL , Wilkins Courtney , Green Richard , Gale Michael J 
Published: January 2023

Abstract
RIG-I-like Receptors (RLRs), RIG-I, MDA5 and LGP2, play critical roles in innate immune defense against RNA viruses and are central to host immunity. RIG-I and MDA5 signal through CARDs to induce innate immune activation while LGP2 lacks these signaling domains but is thought to function as an RLR cofactor. During West Nile Virus (WNV) infection RIG-I and MDA5 work in tandem to initiate innate immune responses but the role of LGP2 in WNV innate immunity is not well-defined. Here we applied virologic, genetic, and bioinformatics approaches to assess innate immune signaling and global gene expression response to WNV infection in primary mouse embryonic fibroblasts (MEFs) and bone marrow derived macrophages (BMMs) from mice lacking RIG-I, MDA5, or LGP2, as well as from mice lacking both RIG-I and MDA5 (DKO). RNAseq analysis defined the distinct roles of RIG-I and MDA5 in induction of innate immune gene expression against WNV. Importantly, we found that LGP2 uniquely controls genes involved in innate immunity when compared to RIG-I and MDA5. We identify an LGP2-specific gene signature that reveals a unique, non-redundant role in innate immunity against WNV. Further, we used a multiplex cytokine assay to determine unique cytokine profiles for each RLR-deficient cell type, suggesting that these distinct transcriptomes lead to functional consequences in response to WNV. A model of unique actions of RLRs in WNV infection will be presented.
CD28 induces mitochondrial respiration through Slp-76 in Long-Lived Plasma Cells for ROS-dependent survival.
Authors: Utley Adam , Carlson Louise , Ventro Daniela , Dupuis Megan Murray , Mahpour Amin , Maharaj Shivana , Collins Katherine , Chavel Colin , Lee Kelvin P 
Published: January 2023

Abstract
Sustained humoral immunity is dependent upon bone marrow (BM) resident long-lived plasma cells (LLPCs). We have shown that CD28 signaling in LLPCs is necessary for their survival and antibody production; however, the mechanistic basis for this is unclear. In T cells, CD28 induces glycolysis at the expense of mitochondrial respiration. To our great surprise, CD28 induces mitochondrial respiration and increases the spare respiratory capacity in LLPCs, but not in short lived plasma cells (SLPCs), through Slp-76. While not affecting glycolysis, CD28 does increase the glycolytic capacity and glycolytic reserve specifically in LLPCs. Paradoxically, the mitochondrial respiration dependent production of reactive oxygen species (ROS) is required for CD28 mediated survival. Mechanistically, ROS dependent activation of NFkB drives Irf4 expression, which itself upregulates myc, both of which have been described as central regulators of metabolism in T cells. In addition, CD28 drives myc-dependent mitochondrial biogenesis in LLPCs, thereby sustaining mitochondrial respiration-dependent ROS. This leads to a self-reinforcing model wherein CD28 induces mitochondrial respiration for ROS-dependent activation of Irf4 and myc, which then drive further mitochondrial biogenesis and enhanced metabolic fitness for LLPC survival. Our work suggests that CD28, by increasing metabolic fitness, may provide a qualitatively distinct program of longevity that allows greater competitive advantage for survival in the BM microenvironment. CD28 may therefore regulate LLPC induction, survival, and function, making it an attractive target for the augmentation of vaccine design as well as in the alleviation of antibody mediated autoimmunity.
miRNAs are critical for the regulation of RAG expression and secondary Ig rearrangement in peripheral B lymphocytes
Authors: Koralov Sergei B , Coffre Maryaline , Benhamou David , Blumenberg Lili , Riess David , Snetkova Valentina , Hines Marcus , Chakraborty Tirtha , Jensen Kari , Chong Marc , Blelloch Robert , Littman Dan R , Melamed Doron , Skok Jane A , Rajewsky Klaus 
Published: January 2023

Abstract
The differential expression of miRNAs throughout B cell development suggests that these ncRNAs contribute to stage-specific regulation of the intricate transcriptional program during B cell development. Conditional ablation of Dicer or deletion of the miR-17~92 cluster in early pro-B cells, revealed a critical role of miRNAs in B cell differentiation.
In the present study we compare the phenotypes of mice in which enzymes critical for miRNA biogenesis, Dicer, Drosha and DGCR8 are conditionally ablated in B lymphocytes, allowing us to definitively explore the role of miRNAs in B cell development and function. Global ablation of miRNAs in B lymphocytes lead to an early block in B cell development. Rescue of B cell surviva by overexpression of the anti-apopotic factor Bcl2 revealed that in the absence of miRNAs, B cells in the periphery expressed low levels of Ig heavy chain without expressing light chain. We demonstrate that miRNA-deficient B cells fail to regulate recombination machinery in the periphery, resulting in ongoing Ig light chain gene rearrangement. In addition to the upregulation of RAG1/2 in peripheral B cells, we demonstrated ongoing DNA double strand breaks at Ig light chain loci and upregulation of surrogate light chain components. We show that these events occur downstream of deregulated PI3K signaling and we recapitulate many of these defects in wild-type B lymphocytes by targeting individual components of PI3K signaling network. Furthermore, we achieve complete rescue of miRNA deficient B cells when we introduce a pro-survival Bcl2 transgene along with an Ig transgene resistant to light chain editing. Our data highlight an important and novel role for miRNAs in the maintenance of a mature phenotype in peripheral B cells.
Distinct functions of RIP1 in immune homeostasis revealed using novel animal models
Authors: Dowling John P , Zhang Jianke 
Published: January 2023

Abstract
RIP1 was originally identified as a protein associated with Fas and TNFR1, which can trigger apoptosis. However, initial studies indicated that RIP1 is dispensable for apoptotic signaling. Instead, cells lacking RIP1 are defective in TNFR1-induced activation of NF-kB, a critical player involved in pro-survival signaling. Recent studies indicate that a certain form of necrosis-like death, necroptosis, requires RIP1. In contrast, the Fas-associated death domain (FADD) protein appears to play an obligatory role in apoptosis induced by Fas and TNFR1. However, the embryonic lethality phenotype of fadd−/− mice had remained a long-standing enigma, until analysis was performed to induce simultaneous deletion of both FADD and RIP1. The resulting fadd−/−rip1−/− double mutant mice displayed normal embryogenesis, indicating that fadd−/− embryos die of RIP1-dependent necroptosis. On the other hand, absence of RIP1 blocks postnatal development. Most recently, studies including ours demonstrated that only when both FADD and RIP3 were deleted will rip1−/− mice survive to adulthood. This result indicates perinatal lethality in RIP1-deficient mice is due to not only FADD-mediated apoptosis but also RIP3-dependent necrosis. Interestingly, we found that lack of RIP1 greatly diminished lymphoaccumulation disease in fadd−/−rip3−/− mice. To investigate RIP1 functions in adult immune cells, we performed conditional deletion of RIP1 in lineage committed lymphoid cells. Viable hypomorphic mutant mice with selective loss of function were employed to delineate the complex signaling pathways mediated by RIP1 in vivo. The results revealed a novel mechanism in the adult lymphoid system, which is distinct from the role of RIP1 in neonatal cells.
Characterization of notch and toll-like receptor interactions in macrophages against Paracoccidioides brasiliensis
Authors: Romera Lavínia Dal’Mas , Jannuzzi Grasielle Pereira , Almeida Sandro Rogério 
Published: January 2023

Abstract
Paracoccidioidomycosis (PCM) is a systemic mycosis of deep nature and granulomatosis that preferably affects the lung tissue and can disseminate to other organs and tissues, and is caused by Paracoccidioides brasiliensis, a thermal dimorphic fungus. Macrophages, cells that have an important role in regulation of immune response, recognize this fungus through pattern recognition receptors (PRR), such as Toll-like receptor (TLR). Recently it has been demonstrated the importance of Notch receptors in regulation the activity of macrophages in immune response, and also that TLR acts together with Notch receptor. Given that Notch and TLR signaling are involved in modulating macrophage function, we evaluated the ability of the fungus modulate the activation of these pathway. Our data demonstrated that activation of TLR4 in macrophages is dependent of Notch 1 receptor, and promotes an increase of IL-6, this cytokine is important to the establishment of PCM. We also observed that the increased level of IL-6 is associated with decrease of TNF-alfa, and phagocitosys. Moreover, when Notch receptor was inhibited, we observed a decreased activation of TLR4 and TLR2, decreased of IL-6 and fungal load, but an increase of TNF-alfa and phagocitosys. We also observed a decrease of fungal load in bone marrow macrophages from TLR4 knockout mice. Similar results are seen in vivo with Notch inhibition, with a decrease of fungal load. This results suggest that P. brasiliensis utilizes Notch-TLR signaling as an escape mechanism.
Profiling CD8+ CD103+ T cells in the Toxoplasma gondii infected brain
Authors: Landrith Tyler , Noor Shahani , Wilson Emma H 
Published: January 2023

Abstract
Toxoplasma gondii is an obligate intracellular protozoan parasite. The parasite evades clearance by the immune system and instead persists in an encysted state within the brain parenchyma. The unique environment of the brain requires a tightly regulated immune response in which T cells are essential. Nonetheless, the mechanistic details of the chronic T cell response to the parasite remain incomplete. Flow cytometry analysis reveals phenotypic diversity among brain infiltrating T cells. CD8+ CD103+ T cells form a notable proportion of this group, comprising nearly 40% of the CD8+ T cell population at the late chronic stage. Expression of CD103 can define a tissue resident memory T cell (Trm). Whether Trm could play a role in control of a chronic infection has not yet been defined. Using flow cytometry and in situ immunostaining, we show that this population is specific to the parasite and can be found throughout the infected brain including the E-cadherin positive regions of the choroid plexus, the perivascular space, and within the parenchyma in proximity to the parasite cyst. Furthermore, using RNAseq analysis, we present preliminary data establishing that this population exhibits a unique transcriptional profile relative to other CD8+ T cells in the brain and periphery. This data suggests that CD8+ CD103+ T cells in the brain are indeed a functionally distinct population, laying the groundwork for further analysis.
Aspergillus fumigatus strain-specific host response is regulated by glucose sensing.
Authors: Caffrey Alayna Katherine , Beattie Sarah R , Blaseg Nate , Hilmer Kimberly M , Zickovich Julianne M , Cramer Robert A , Obar Joshua J 
Published: January 2023

Abstract
Our knowledge of how Aspergillus fumigatus growth is controlled within the respiratory tract is developing, but still enigmatic. Recruitment of neutrophils and inflammatory monocytes is critical to control fungal germination. We have recently found that the CEA10 and Af293 strains of A. fumigatus induce unique inflammatory leukocyte responses. Here, we aim to understand why these A. fumigatus strains induce different immune responses and how this affects fungal-induced immunopathology and disease outcome. We used an immunocompetent murine model of invasive pulmonary aspergillosis to evaluate the immune response induced by CEA10 and Af293. We observed that CEA10 undergoes significantly greater germination than Af293, which was regulated by its ability to sense glucose through CreA-mediated signaling. Moreover, the CEA10 strain induced greater lung damage, vascular leakage, and inflammation. These findings suggest the inflammatory response to A. fumigatus might be regulated in a stepwise manner in response to the threat posed by the specific A. fumigatus strain. Specifically, the Af293 strain, which swells but fails to germinate, activates the inflammasome leading to IL-1beta-dependent neutrophil recruitment. In contrast, the CEA10 strain is able to germinate efficiently within the lung, leading to necrotic host cell death, IL-1alpha release, and subsequent IL-1alpha dependent neutrophil recruitment. Clinically, our data support the idea that A. fumigatus strain phenotypic variation may significantly contribute to disease outcomes. Understanding why different A. fumigatus strains induce distinct immune pathology can reveal novel immunotherapeutic targets for the treatment of invasive aspergillosis.
Apicidin mediated attenuation of MRSA virulence corresponds with quorum sensing inhibition and enhanced immune effector responses.
Authors: Parlet Corey P , Kavanaugh Jeffrey S , Crosby Heidi A , Cech Nadja B , Oberlies Nicholas H , Horswill Alexander R 
Published: January 2023

Abstract
As the leading cause of infectious mortality in the United States, S. aureus-induced disease represents a major healthcare problem. The alarming rise of infections caused by virulent, antibiotic resistant strains, such as emerging methicillin-resistant S. aureus (MRSA) isolates, highlight the need for new interventions that inhibit MRSA pathogenicity and potentiate host defense responses. The expression of MRSA virulence factors is a function of agr-driven quorum sensing, making this system a promising target for anti-MRSA therapies. Through agr-reporter-based screens, a class of compounds, called apicidins, were found to inhibit quorum-sensing activity across MRSA isolates. To test the efficacy of apicidin in vivo, mice were challenged intradermally with 2×107 MRSA (+/−) 5 mg apicidin. The abatement MRSA virulence in the apicidin-treated group was demonstrated by reduced: weight loss, dermonecrosis and cutaneous bacterial burden. By challenging mice with an agr-reporter strain, we also found that the apicidin-mediated attenuation of MRSA pathogenesis corresponded with reduced quorum sensing activity in vivo. To evaluate apicidin’s impact upon anti-MRSA effector responses, we assessed polymorphonuclear neutrophil (PMN) accumulation and function at cutaneous sites of infection. Flow cytometric analysis revealed that apicidin increased the density of PMNs within infected wounds 24 hours post infection. In addition, we found that the number of PMNs that phagocytosed MRSA organisms in vivo was increased in lesional skin preparations from apicidin treated mice. Together, these results indicate that apicidin-mediated quorum quenching represents a novel strategy to limit MRSA virulence and promote host defense.
Identification and characterization of CD1-restricted T cells
Authors: Souter M N , Nguyen-Robertson C V , Ross F J , Reddiex S J. J , Waddington J , Van Rhijn I , Eckle S B. G , McCluskey J , Aldrich A P , Rossjohn J , Moody B , Godfrey D I , Pellicci D G 
Published: January 2023

Abstract
Most studies of T cells have focused on those that respond to foreign peptides. However, other specialized populations of T cells exist that recognize lipid antigens and make up a substantial component of the human immune system. These lipid reactive T cells recognize antigens presented by antigen presentation molecules from the CD1 family. Four CD1 molecules exist (CD1a, CD1b, CD1c and CD1d), and each is capable of presenting a unique repertoire of lipids antigens to T cells. Much of what we have learned about lipid reactive T cells stems from studies of CD1d restricted NKT cells as these are present is both mice and humans and can be detected using CD1d/α-GalCer tetramers. In contrast, our understanding of the biology of CD1a, CD1b, CD1c restricted T cells is relatively limited. However, the recent generation of CD1a, CD1b and CD1c tetramers is helping with the identification and characterisation of these CD1-restricted T cells.
We have produced CD1 tetramers loaded with mammalian self-lipids or lipid antigens from Mycobacterium tuberculosis. In conjunction, with a tetramer-based enrichment method, we have successfully identified both autoreactive and microbial lipid antigen specific T cells from healthy human blood. We reveal the phenotypic characteristics of these CD1-restricted T cells and used CD1 mutagenesis to provide new insight into TCR recognition of CD1-lipid antigen complexes. Collectively, these studies will serve as a basis for future studies of lipid reactive T cells in health and disease.
Mother’s ‘genetic’ little helpers: microchimeric maternal cells promote reproductive fitness and survival of non-inherited traits
Authors: Kinder Jeremy Michael , Jiang Tony , Ertelt James , Xin Lijun , Strong Beverly , Shaaban Aimen F. , Way Sing Sing 
Published: January 2023

Abstract
Reproductive success among outbred placental mammalian species requires active tolerance in mothers to foreign paternal antigens expressed by the developing fetus. Although this essential necessity for immunological tolerance has primarily been examined from the perspective of maternal responsiveness to foreign paternal antigens expressed by the developing fetus, exposure to maternal tissue during in utero development also imprints tolerance to genetically foreign non-inherited maternal antigens (NIMA) that persists into adulthood. Nonetheless, until now the biological advantages reinforcing conservation of tolerance to NIMA across eutherian mammals remained unclear. We show vertically transferred maternal cells that establish microchimerism in offspring promote systemic accumulation of regulatory T cells with NIMA specificity. In females, NIMA-specific regulatory T cells expand during pregnancies sired by males expressing alloantigens with overlapping NIMA specificity, thereby averting fetal wastage normally triggered by disruptions of fetal tolerance. Thus, reproductive fitness among females carrying embryos expressing paternally inherited antigens overlapping with NIMA is selectively enhanced. These findings demonstrate that genetic fitness, canonically thought to be restricted to Mendelian inheritance, is enhanced in female placental mammals through vertically transferred maternal cells that promote conservation of NIMA and enforce cross-generational reproductive benefits. Future studies will investigate the cellular and molecular phenotype of the microchimeric maternal cells to elucidate specific mechanisms that drive NIMA-specific regulatory T cell accumulation.