bluuebunny/crossref_metadata_2025_split huggingface dataset:
IFNs induce prolonged hematopoietic suppression via IL-18-induced cell death during shock-like Ehrlichial infection
Authors: Howard Jennifer E , Cruz Jose Luis , MacNamara Katherine C 
Published: February 2023

Abstract
The long-term effects of shock-like infection on hematopoietic stem and progenitor cells (HSC/HSPC) has not been carefully investigated. Using Ixodes ovatus ehrlichia (IOE), a tick-born pathogen that causes severe shock-like illness and bone marrow (BM) aplasia, we explored mechanisms that cause hematopoietic suppression. During IOE infection, type I IFNs promote loss of HSPCs via direct (cell death) and indirect mechanisms (quiescence). Mice lacking IFNαβ receptor (IFNαR−/−) had improved survival relative to WT mice. IFNγR−/− mice had profound BM aplasia and mortality, like WT mice, however mice lacking both type I and II IFN receptors (IFNαR;IFNγR−/−) had protected HSPCs and improved survival, even relative to IFNαR−/− mice. WT and IFNγR−/− mice had reduced HSPCs and increased levels of IL-18 relative to IFNαR−/− and IFNαR;IFNγR−/− mice, while IL-18R expression induced during IOE required IFNγ signaling. IL-18-deficiency prevented IOE-induced BM aplasia and reduced HSC quiescence and necrotic (7AAD+) cells. To test whether IL-18R-signaling acted on HSPCs directly, we generated WT: IL-18R−/− mixed BM chimeras. IL-18R−/− cells had an advantage over WT cells and IL-18R was intrinsically required for increased HSPC cell death. In mixed BM chimeras given antibiotics to allow recovery from acute infection, we found that two weeks post-infection IL-18R−/− HSPCs were present at higher numbers and IL-18R−/− cells had greater functional output in colony-forming unit assays. Our data support IFN driven hematopoietic suppression through IFNαR-dependent induction of IL-18 and IFNγR-dependent IL-18R expression, and that direct effects of IL-18 on HSPCs during infection-induced shock may have long-lasting effects on HSCs.
B7-CD28 co-stimulation enforces central tolerance by thymic clonal deletion and Treg cell generation through distinct mechanisms
Authors: Watanabe Masashi , Lu Ying , Breen Michael , Hodes Richard J 
Published: February 2023

Abstract
To establish central T cell tolerance in the thymus, thymocytes expressing TCR strongly reactive to self-Ag-MHC complex are eliminated from the conventional T cell (Tconv) repertoire by two distinct processes, clonal deletion or clonal diversion to non-conventional T cell lineages such as Foxp3+ regulatory T (Treg) cells. We analyzed the requirements for B7-CD28 co-stimulation for thymic clonal deletion and Treg cell generation of endogenous tissue-restricted-antigen (TRA)-specific thymocytes. We found that: 1) both clonal deletion and Treg cell generation of TRA-specific thymocytes were B7-CD28-dependent, and that clonal deletion had a greater effect than Treg diversion in eliminating TRA-specific T cells from the Tconv repertoire; 2) B7-expressing APC requirements differed for clonal deletion and Treg generation; and 3) although B7-CD28 mediated both clonal deletion and Treg cell generation, CD28 cytoplasmic domain requirements for these two processes were different. These results indicate that qualitatively distinct CD28 signaling determines fates of strongly self-reactive thymocytes. To further characterize the CD28 signaling pathways involved in clonal deletion and Treg cell generation, single cell transcriptomic analyses of TRA-specific thymocyte are underway.
CCR4 and CCR7 differentially regulate thymocyte subset localization with distinct outcomes for central tolerance
Authors: Li Yu , Lancaster Jessica N , Nam Seohee , Seo Hyemin , Ehrlich Lauren Ilyse Richie 
Published: February 2023

Abstract
Central tolerance is established as T cells mature in the thymus by the combined effects of clonally deleting autoreactive thymocytes or inducing their diversion to the Treg lineage. To ensure T cell tolerance to diverse self-antigens, thymocytes must efficiently enter the medulla and scan heterogeneous antigen presenting cells, which display the majority of the peptidome in a sparse mosaic. While it is widely accepted that CCR7 contributes to central tolerance by promoting thymocyte medullary localization and rapid migration therein, the contribution of CCR4 to these processes remains unclear. For example, it is not known whether CCR4 is simply redundant to CCR7 in promoting medullary entry or if it plays a distinct role in central tolerance. Here, we report that early post-positive selection thymocytes undergo chemotaxis towards CCR4 ligands, while progressively mature cells migrate towards CCR7 ligands. Synchronized positive selection assays reveal that CCR4 is upregulated within hours of positive selection signaling, while CCR7 upregulation is delayed. 2-photon microscopy shows that CCR4 facilitates entry of early post-positive selection cells into the thymic medulla, while CCR7 promotes medullary accumulation of mature subsets. These findings suggest that CCR4 and CCR7 have non-redundant roles in negative selection. Consistent with this possibility, flow cytometric analysis reveals that CCR4 deficiency results in a selective decline in early-stages of negative selection, while CCR7 deficiency impairs only late-stage negative selection. Our data support a new model in which CCR4 and CCR7 mediate medullary entry of different thymocyte subsets and play distinct roles in enforcing central tolerance.
Mapping the thymic neuronal connectome using rabies virus retrograde and anterograde tracers
Authors: Ayasoufi Katayoun , Yokanovich Lila T , Pfaller Christian K , Jin Fang , Johnson Aaron J 
Published: February 2023

Abstract
Immune organ innervation by the peripheral nervous system enables autonomic function in the development and maintenance of immunity. Specifically, the role of thymic innervation in health and following neurological insults is unknown. An in depth identification of the connectome within the thymus and the extent to which nervous impulses delivered to the thymus affect T cell development and other biological processes within the thymus is needed. We sought to determine the exact nature of innervation within the thymus. Using both flow cytometry and confocal microscopy, we determined that the thymus contains both extrinsic neuronal processes (cell bodies outside of the thymus), and surprisingly, intrinsic neurons (cells bodies within the thymus). We further verified that subsets of neurons within the thymus express tyrosine hydroxylase, BIII tubulin, and/or NeuN, and are distinct from epithelial cells (EPCAM+, UEA1+, Ly51+) and tuft cells (DLCK1+). Furthermore, neuronal cell bodies found within the thymus did not express AIRE, consistent with their identity as neurons. Subsets of intrinsic neurons within the thymus express MHCII implying a potential role in T cell development. Importantly, using rabies virus retrograde and anterograde neurotracers, we mapped a novel, previously undescribed, connectome of neurons within the thymus. Finally, we determined that both epithelial cells and neurons are significantly reduced in RAG deficient mice, indicating a possible co-regulation between thymic neurons and epithelial cells. In summary, we describe a novel network of neurons within the thymus and put forward implications of the thymic connectome’s role in T cell development and establishment of thymic architecture.
AI-guided use of balanced peroxisome proliferator-activated receptor a/g dual agonist finetunes macrophage responses in inflammatory bowel disease
Authors: Katkar Gajanan Dattatray , Sayed Ibrahim , Anandachar Mahitha Shree , Castillo Vanessa , Vidales Eleadah , Toobian Daniel , Usmani Fatima , Taheri Sahar , Dang Dharanidhar , Sawires Joseph , Leriche Geoffray , Yang Jerry , Sandborn William , Das Soumita , Sahoo Debashis , Ghosh Pradipta 
Published: February 2023

Abstract
A computational platform, the Boolean network explorer (BoNE) has recently been developed; it enables querying and navigating invariant Boolean Implication Networks of disease maps for prioritizing high-value targets. Here we used BoNE derived Inflammatory Bowel Disease (IBD)-map and prioritize two nuclear receptors, PPARa and PPARg. Balanced agonism of PPARa/g was predicted to impact macrophage function, ameliorate colitis in network-prioritized animal models, ‘reset’ the gene expression network from disease to health. Predictions were validated using a balanced and potent PPARa/g-dual agonist (PAR5359) in two murine models, i.e., Citrobacter rodentium- and DSS-induced colitis. Mechanistically, we show that balanced dual agonists promote bacterial clearance more efficiently than individual agonists both in vivo and in vitro, through the controlled induction of pro-inflammatory cytokines, cellular ROS and gut-barrier protection. PPARa is required and its agonism is sufficient to induce the pro-inflammatory response that is essential for bacterial clearance and immunity, but PPARg-agonism blunts these responses, delays microbial clearance. Balanced agonists achieved controlled inflammation, barrier protection and reversed the network towards the healthy side of disease. When tested on IBD-patients-derived PBMCs, PAR5359 reversed the defective bacterial clearance observed in these subjects. These findings not only deliver a macrophage modulator in IBD but also highlight the potential of BoNE to accelerate and enhance the precision of drug discovery in various diseases.
Unconjugated bilirubin modulates Th17-cell immunity by curbing glycolysis-related genes
Authors: Longhi Maria Serena , Vuerich Marta , Wang Na , Kalbasi Ahmadreza , Moss Alan C. , Cheifetz Adam S. , Robson Simon C. 
Published: February 2023

Abstract
Unconjugated bilirubin (UCB) controls Th17-cell function by upregulating the ectonucleotidase CD39 and through activation of aryl-hydrocarbon-receptor (AhR), a modulator of adaptive immunity. UCB-induced CD39 upregulation is defective in Th17-cells of Crohn’s disease (CD) patients. Increasing evidence suggests a role for AhR in regulating glucose metabolism. In this study we tested whether UCB modulates Th17-cell metabolism and whether impaired Th17-cell response to UCB results in metabolic alterations in CD.
Th17-cells were differentiated from circulating CD4-cells of 31 healthy controls (HC) and 22 CD patients. Using a multiplex gene expression panel including genes of 8 metabolic pathways, we found that UCB markedly downregulated glycolysis-related genes, particularly phosphoglycerate-kinase-1 (PGK1) and aldolase-A (ALDOA); this effect being prominent in Th17-cells derived from HC but not from CD patients. Reduced Pgk1 and AldoA was also noted in mesenteric-lymph-nodes of mice exposed to dextran-sulfate-sodium-induced colitis and treated with UCB.
Functionally, UCB decreased the extracellular-acidification-rate and oxygen-consumption-rate of HC Th17-cells, while this effect was not noted in Th17-cells of CD patients. In vitro silencing of PGK1 and ALDOA further enhanced UCB immunoregulatory properties in HC Th17-cells, by boosting CD39 and Tim-3 while containing IL-17.
In conclusion, UCB modulates Th17-cell immunity by downregulating glycolysis-related genes; this property being defective in cells obtained from CD patients. Strategies aimed at blocking/inhibiting glycolytic genes might represent a potential therapeutic tool to restore immune homeostasis in CD and other inflammatory conditions.
Understanding NLRs and AIM2 cellular and molecular signalling in glioblastoma pathophysiology
Authors: Jha Sushmita , Singh Shalini , Saxena Shivanjali , Sharma Nidhi , Agrawal Ishan , Govekar Rukmini , Panchal Pranali , Sridhar Epari , Gupta Tejpal 
Published: February 2023

Abstract
Gliomas are the most prevalent primary brain tumors with immense clinical heterogeneity, poor prognosis and survival. Gliomas arise from glial cells and are heavily infiltrated with innate immune cells. In India high-grade gliomas or Glioblastomas (GBM) account for 59.5% of CNS tumours. A key challenge for clinical management of GBM is its highly heterogeneous nature-between patients and within a single tumour-making current therapies ineffective. The nucleotide-binding domain, and leucine-rich repeat containing receptors (NLRs) and absent-in-melanoma 2 (AIM2) are innate immune receptors crucial for initiation and progression of several cancers. There is a dearth of reports investigating NLRs and AIM2 in glioma pathology.
We are interested in studying the cellular and molecular contribution of NLRs and AIM2 in malignant gliomas in the Indian subcontinent. We previously reported a data-driven approach to identify NLRs, AIM2 and NLR-associated gene expression in gliomas using The Cancer Genome Atlas (TCGA) patient datasets. However, TCGA data is obtained from diverse populations and cellular diversity within individual tumor tissues remains unexplored. In this study we carried out tumour primary cell culture, human brain immunohistochemistry and proteomic analysis and same patient serum controls (n=100). Our results characterize novel cell specific differential expression and signalling profile of several NLR genes (including NLRP3, NLRP12 and ASC) in microglia, astrocytes, endothelial cells and the tumour cell populations in GBM patient tissue. We provide critical insights into innate immune signalling within the GBM microenvironment and identify key markers for future therapeutic interventions.
Evaluating the effect of chronic schistosomiasis on the gut microbiome at the species level
Authors: Smith Jade A , Mhanna Mariam A , Shollenberger Lisa M 
Published: February 2023

Abstract
Schistosomiasis is a neglected tropical disease caused by the trematode helminth Schistosoma mansoni (S. mansoni). Schistosomiasis infection, which is caused by parasitic worms, is a globally important parasitic disease, second only to malaria in its devastation. There is growing evidence that, by shifting the TH1 and TH2 responses, helminth infections can adversely affect the immune system and one expected way is by perturbing the gut microbiota. However, little is known about the effects of chronic schistosomiasis on the composition of the gut microbiota of its mammalian host. Therefore, we collected fresh fecal samples from BALB/c mice (n=3) during the 10 weeks necessary for establishment of a chronic schistosomiasis infection. We then evaluated the composition of the fecal microbiome after 16S rRNA sequencing using open-source software (Qiita). Here, we characterized fecal microbiota changes by analyzing the relative abundance of several specific operational taxonomic units (OTUs) at the species level. Our long-term goal is to deduce the potential relationship between S. mansoni and the functional aspects of these OTUs, thereby understanding the subsequent effect this alteration has on the host. These data support a modification of the mammalian gut microbiome composition by a chronic schistosomiasis infection. These functional changes serve as a foundation for the design of mechanistic studies to unravel the complex relationship between the microbial composition of the mammalian gut microbiome, chronic S. mansoni infection, and the host adaptive immune response.
Mitofusin-2 regulates leukocyte adhesion through the maturation of beta2 integrin activation in differentiation
Authors: Fan Zhichao , Liu Wei , Wang Yueyang , Hsu Alan Y , Lin Tao , Sun Hao , Pachter Joel S , Groisman Alex , Imperioli Matthew , Yungher Fernanda Wajnsztajn , Hu Liang , Wang Penghua , Deng Qing 
Published: February 2023

Abstract
Neutrophils are critical in inflammation and innate immunity. Neutrophil adhesion to vascular endothelium is a crucial step in neutrophil recruitment. Mitofusin-2 is required for neutrophil adhesion, but molecular details are unclear. Here, we demonstrated that β2-integrin-mediated slow-rolling and arrest, but not PSGL-1-mediated cell rolling, are defective in mitofusin-2-deficient neutrophil-like HL60 cells. This adhesion defect is associated with reduced expression of fMLP receptors and β2 integrins as well as the inhibited β2 integrin activation, as assessed by conformational-specific antibodies. Mitofusin-2 deficiency limited the maturation of β2 integrin activation during the neutrophil-directed differentiation of HL60 cells, which is indicated by identified markers CD35 and CD87. Reversed to results in overall HL60 cells, mitofusin-2 knockdown in β2-integrin-activation-matured cells (CD87high population) enhanced integrin activation. Our study illustrates the function of mitofusin-2 in leukocyte adhesion and may provide new insights into the development and treatment of mitofusin-2-deficiency-related disease.
PD-L1 reverse signaling in dermal dendritic cells promotes dendritic cell migration required for skin immunity.
Authors: Lucas Erin D , Schafer Johnathon , Tamburini Beth 
Published: February 2023

Abstract
While the function of the extracellular region of programmed death ligand 1 (PD-L1) through its interactions with PD-1 on T cells is well studied, little is understood regarding signaling via the intracellular domain of PD-L1, termed PD-L1 reverse signaling. The objective of this study is to determine how PD-L1 reverse signaling impacts dendritic cell (DC) function during immune responses. We outline a major role for PD-L1 reverse signaling in the control of DC migration from the skin to the draining lymph node (dLN). We find that total loss of PD-L1 on DCs impairs migration to the dLN following an innate immune stimulus. Using a mutant mouse model, we identify a TSS signaling motif within the intracellular domain of PD-L1. This TSS motif proves critical for promoting chemokine mediated DC migration to the dLN during inflammation. The loss of DC migration, in the PD-L1 TSS mutant, leads to a significant decline in T cell priming when DC trafficking is required for antigen delivery to the dLN. We found that the TSS motif is required for chemokine receptor signaling, and disruption of this motif impairs signaling downstream of the Gα subunit of the heterotrimeric G protein complex, leading to impairment in ERK phosphorylation and actin polymerization in DCs. Finally, we demonstrate that ligation of PD-L1 by one or more of the known binding partners of PD-L1, CD80 and PD-1, appears to support migration of DCs to the dLN. These studies identify a novel function for PD-L1 reverse signaling in supporting DC migration during initiation of immune responses, and raises questions about the potential impact of PD-L1 antibody blockade on DC function in patients with cancer.
Dopamine induces functional extracellular traps in microglia
Authors: Agrawal Ishan , Sharma Nidhi , Saxena Shivanjali , Arvind S. , Chakraborty Debayani , Chakraborty Debarati Bhunia , Jha Deepak , Ghatak Surajit , Epari Sridhar , Gupta Tejpal , Jha Sushmita 
Published: February 2023

Abstract
Dopamine (DA) is central to neurological functions like motivation, movement and reward (Klein et al. 2019). While its role in diseases like Parkinson’s, Alzheimer’s and schizophrenia are well studied, its role in regulating immune functions have just started to unfold. DA receptors are present on almost all immune cells and they regulate innate and adaptive immunity (Matt and Gaskill 2020). We have investigated the role of DA in the formation of extracellular traps (ETs) in microglia. We report that DA can induce ETs in BV2 microglia cell line and primary adult human microglia. ETs are composed of decondensed chromatin and are embedded with proteins including antimicrobial proteins like myeloperoxidase and histone. We confirmed ETs formation by staining them with DAPI, myeloperoxidase and/or DNA/Histone H1. The presence of traps in culture supernatant was confirmed by measuring SYTOX Green absorbance. To check for the mechanism of ETs formation by BV2 cells, we performed MTT assay and treated cells with N-acetyl L-cysteine or cytochalasin D. We saw that the traps were formed independent of cell death, reactive oxygen species (ROS) and actin polymerization. We further confirmed that DA induced microglia traps are functional as they were able to trap FITC tagged Escherichia coli. Lastly we checked the presence of microglia ETs in Glioblastoma multiforme tissues as recently glioma cells have been reported to secrete DA and possess DA receptors (Caragher et al. 2019). We confirmed and quantified the traps present in GBM by an unbiased algorithm. Our findings demonstrate that DA may play significant role in sterile neuro-inflammation by inducing microglia ETs.
Gut derived T cells in the joint display an activated regulatory phenotype following tissue injury
Authors: Lefferts Adam R , Norman Eric , Kantheti Uma , Kuhn Kristine A 
Published: February 2023

Abstract
Numerous studies have implicated a gut-joint axis in the pathogenesis of spondylarthritis (SpA), but the exact mechanisms that connect the intestine and joint remain unclear. Here we sought to identify one potential mechanism, the direct trafficking of immune cells from gut tissue to the inflamed joint enthesis, the site of injury in SpA. To track gut-derived cells in vivo, we utilized the KikGR transgenic mouse model, in which colonoscopy-guided exposure to 405nm light causes photo-conversion of the transgene and labeling of cells in situ. In this manner we selectively label the epithelium, including intraepithelial lymphocytes (IELs), while avoiding cells in the lamina propria. Within 24 hours after photo-conversion, with a maxima at 72 hours, gut-labeled T cells appear in the Achilles enthesis. This trafficking occurs constitutively, with gut-derived T cells comprising ~10% of total tissue T cells. Following the induction of inflammation by the injection of 20mg of Complete Freund’s Adjuvant (CFA) into the hind hock, we observed 25.2% of gut-derived T cells were FoxP3+ compared to 4.8% in the unlabeled population (p=0.0063). Within this Foxp3+ subpopulation we also observed significant enrichment of CD69 (p=0.0013) and a trend towards increased CD103 (p=0.065) expression, suggestive of memory residence. These enrichments were not observed in the contralateral un-injected hock, implying that inflammatory mediators are required for the recruitment of gut-derived regulatory T cells to establish residence. These data demonstrate bona-fide gut joint trafficking of T cells and suggest a regulatory role for mIELs. Ongoing work focuses on potential functional differences in mIELs derived from healthy vs inflamed mucosa.