bluuebunny/crossref_metadata_2025_split huggingface dataset:
Deciphering the IFN-γ-mediated immunopathology during Plasmodium yoelii N67C infection
Authors: Lacerda-Queiroz Norinne , Riteau Nicolas , Eastman Richard , Moore Ian , Sher Alan , Jankovic Dragana , Su Xin-zhuan 
Published: January 2023

Abstract
Immune response plays an important role in controlling malaria infection; however, excessive inflammatory response can lead to severe disease. Here we investigate the mechanism of pathogenesis in mice after infection with a virulent rodent malaria parasite, Plasmodium yoelii nigeriensis strain N67C. Previous studies showed that C57BL/6-infected mice display high parasitemia, strong pro-inflammatory response, culminating in extensive splenic damage and host lethality at around 7 days post-infection. The present work aims to characterize the cellular and molecular events associated with host immune-mediated pathology in response to N67C parasite. Mice were infected with 106 infected red blood cells by intraperitoneal injection. C57BL/6-infected mice develop progressive inflammation in the spleen, characterized by intense cellular death and up-regulation of pro-inflammatory cytokines (notably IFNγ, IL-6, CCL2 and CXCL1). Interestingly, we identified splenic CD4+ and CD8+ T cells as major sources of IFN-γ as early as day 4 post-infection. Additionally, we demonstrated that IFN-γ was a major mediator of splenic pathology because its absence or blockade prolonged host survival and prevented excessive host inflammatory response. Moreover, by employing chimeric mice, we showed that the absence of IFN-γ receptor in the non-hematopoietic compartment protected mice from early death. Elucidation of this IFN-γ signaling mechanism may enable further development of interventions to decrease human morbidity and mortality associated with severe malaria.
Commensal exopolysaccharides induce M2 macrophages that prevent pathogen-induced colitis
Authors: Paynich Mallory L , Jones Sara E , Knight Katherine L 
Published: January 2023

Abstract
Trillions of bacteria live within the gastrointestinal tract and are critical for maintaining intestinal homeostasis; however, the mechanisms utilized by specific bacterial molecules to contribute to homeostasis are not well understood. We utilize a mouse model in which a single oral dose of the probiotic, B. subtilis, protects mice from acute colitis induced by the enteric pathogen C. rodentium. Our goal is to elucidate the mechanism by which B. subtilis prevents inflammation. We identified exopolysaccharides (EPS) to be the active molecule of B. subtilis, and a single dose of EPS protects mice from disease. EPS binds F4/80+CD11b+ peritoneal macrophages (MΦ), and following EPS treatment, MΦ increase expression of CD206, Arg1, YM-1, and IL-4Rα, and inhibit T cell activation and proliferation in vitro, indicative of M2 MΦ. Induction of M2 MΦ is TLR4-dependent, and in mice treated with clodronate liposomes to deplete MΦ, EPS no longer protects mice from disease. Addition of anti-TGFβ neutralizing antibodies removed the inhibitory effect of M2 MΦ suggesting that EPS-induced M2 MΦ produce TGFβ to inhibit T cell proliferation in vitro. CD4+ T cells drive much of the inflammation associated with C. rodentium infection, and we hypothesized that EPS inhibits CD4+ T cell responses in vivo. Accordingly, we measured levels of IFNγ (Th1), IL-17 (Th17), and IL-13 (Th2) in splenic T cells following EPS treatment and found decreased levels of these cytokines. We hypothesize that EPS-induced M2 MΦ mediate inhibition of CD4+ cell responses in vivo, preventing acute colitis induced by C. rodentium. The data suggest that EPS-induced M2 MΦ mediate protection from C. rodentium disease by inhibiting CD4+ T cell responses through production of TGFβ.
Cyclic dinucleotide detection by RECON controls innate immune responses
Authors: McFarland Adelle , Luo Shukun , Ahmed-Qadri Fariha , Thayer Elizabeth F. , Tabakh Hannah , Tong Liang , Woodward Joshua J. 
Published: January 2023

Abstract
Host cells have evolved a sophisticated arsenal of germ-line encoded pattern recognition receptors that detect a vast array of microorganisms in distinct tissues and cellular compartments. Cytoplasmic sensors monitor for microbes that gain access to the host cell cytosol following breach of the plasma membrane or intracellular invasion. This sensing is achieved through detection of invariant molecular patterns associated with microorganisms or cell stress responses that indicate the presence of a pathogen. Cyclic dinucleotides (cdNs) of both bacterial and host origin have emerged as important molecules that are sensed during infection. Details about the receptors cdNs engage in host cells and the responses those interactions elicit are just coming to light. We have recently discovered the first bacterial cdN-specific pattern recognition receptor, the oxidoreductase RECON. Our work on this receptor has revealed its central role in directing innate immune responses when engaged by bacterial cdNs. These findings reveal a new pattern recognition receptor specific for bacterial cdNs that orchestrates cytosolic immune surveillance by shaping downstream inflammatory gene activation.
The structural basis of IRF-3 recruitment, activation, and targeting in innate immunity
Authors: Li Pingwei 
Published: January 2023

Abstract
Type I interferons (IFNs) are key cytokines mediating innate antiviral immunity. cGAS, RLRs, and TLRs recognize microbial DNA, RNA, and LPS to induce the expression of type I IFNs. These signaling pathways converge at the recruitment and activation of IRF-3. STING, MAVS, and TRIF mediate the recruitment of IRF-3 through a conserved pLxIS motif. Here we show that the pLxIS motif of phosphorylated STING, MAVS, and TRIF binds to IRF-3 in a similar manner, while residues upstream of the motif confer specificity. The structure of IRF-3 phosphomimetic mutant S386/396E bound to CBP reveals that the pLxIS motif also mediates IRF-3 dimerization and activation. Moreover, rotavirus NSP1 employs a pLxIS motif to target IRF-3 for degradation. However, phosphorylation of NSP1 is not required for its activity. These results suggest a concerted mechanism for recruitment and activation of IRF-3 that can be subverted by viral proteins to evade innate immune response.
CD28 co-stimulatory signaling and AP-1 transcription factor are involved in the establishment of open chromatin during T cell activation.
Authors: Yukawa Masashi , Jagannathan Sajjeev , Kartashov Andrey , Barski Artem 
Published: January 2023

Abstract
Upon encountering an antigen, naïve T helper (Th) cells are activated, differentiate into several lineages and contribute to immune response. Epigenetic changes at several cytokine and other effector genes during activation has been described previously, but the mechanism behind these changes is not understood. Here, we have profiled open chromatin during human T cell activation using ATAC-Seq approach and identified the regions where epigenetic changes take place genome-wide. Open chromatin formation correlated with induction of gene expression at nearby genes. This gene set was also enriched for functions related to T cell activation and immune response in GO analysis. T cell activation requires antigen signaling via T cell receptor and co-stimulation via CD28 which in turn result in nuclear translocation of NFAT and AP-1 transcription factors. For this reason, we profiled genome-wide distribution of these proteins during activation by ChIP-Seq. Our results show that 73% of activation-induced open chromatin loci contain binding sites for AP-1, whereas 39% of them bind NFAT. Over 90 % of the binding sites for NFAT were shared with AP-1 binding sites. We and others have previously shown that the lack of co-stimulation results in reduction or delay of AP-1 translocation into the nucleus. In order to confirm the role of AP-1 in establishment of the open chromatin structure during activation we mapped open chromatin in the cells that were activated without co-stimulation. Our data showed that ATAC signal was reduced at the open chromatin sites bound by AP-1 in the absence of co-stimulation, suggesting that CD28 signaling and AP-1 transcription factor are involved in open chromatin formation during T cell activation.
Quantification of lymph node transit times reveals differences in the trafficking behavior of regulatory versus conventional CD4+ T cells
Authors: Tong Alexander , Allen Frederick , Huang Alex Yee-Chen 
Published: January 2023

Abstract
Regulatory T cells (Tregs) express the canonical marker Foxp3 and are critical for suppressing the immune response in homeostatic and inflammatory conditions. Despite how widely studied CD4+Foxp3+ Tregs are in mice, their physiologic trafficking and scanning behavior of antigen-presenting cells in secondary lymphoid organs (SLOs) have yet to be quantitatively analyzed in the intravital setting. Our laboratory has previously described the dynamics of T cell trafficking through SLOs and scanning of dendritic cells (DCs), revealing that CD4+ T cells and CD8+ T cells exhibit different transit kinetics through lymph nodes (LNs). On average, CD4+ T cells spend less time scanning for self-peptide/MHC (self-pMHC), dwell shorter in LNs, and egress faster compared to CD8+ T cells. Here we use flow cytometry and 2-photon laser scanning microscopy (2-PLSM) to quantitate the homeostatic trafficking behavior and surveillance strategy of Tregs in LNs and to compare their behavior to conventional T cells (Tconvs). Our data reveal surprising differences in Treg versus Tconv trafficking in mesenteric versus other peripheral LNs. Furthermore, we find that Treg LN transit time is heavily dependent on recognition of self-pMHC. Finally, we use intravital 2-PLSM to quantify the contribution of self-pMHC recognition to Treg kinetics and scanning of DCs in peripheral and mesenteric LNs. These results add quantitative data to the emerging paradigm that self-pMHC interactions dynamically control homeostatic Treg retainment and localized suppressive function in peripheral LNs.
Response Gene to Complement-32 promotes Th17 cell differentiation through TGF-β dependent and independent mechanisms
Authors: Rus Violeta , Nguyen Vinh , Tatomir Alexandru , Mekala Armugam Prasad , Rus Horea G 
Published: January 2023

Abstract
Response Gene to Complement (RGC)-32 is an intracytoplasmatic protein expressed in a variety of cells in response to sublytic complement activation, TGF-β and several growth factors. Upon activation it translocates into the nucleus and plays an important role in cells proliferation, migration, angiogenesis and TGF-β induced epithelial mesenchymal transition and fibrosis. A number of signaling pathways including CDC2 kinase, NF-kB, Akt, SMAD2/3, ROCK2 and PKC have been reported to mediate RGC-32 effects in different cell types. We have recently shown that RGC-32 promotes Th17 but not Treg, Th1 or Th2 differentiation in murine CD4+ T cells in vitro. The molecular mechanisms underlying the enhanced Th17 generation by RGC-32 are unknown. Under Th17 conditions, CD4+ T cells from RGC-32 knockout (KO) mice displayed significantly lower IL-6Rα and TGF-βRI mRNA expression. Smad dependent TGFβ signaling was altered in RGC-32 KO T cells as demonstrated by decreased phosphorylation of Smad2, while IL-6 induced STAT3 phosphorylation did not differ between RGC-32 KO and wild-type CD4+T cells. mRNA and protein expression of RORyt, the Th17 lineage specific transcription factor, was significantly lower in RGC-32 KO CD4+ T cells. In addition, RGC-32 KO CD4+T cells expressed significantly lower mRNA levels of the initiator transcription factors, BATF and IRF4. These results suggest that RGC-32 positively regulates the differentiation of the Th17 lineage through TGFβ dependent and independent mechanisms by enhancing the activation of Smad2, IRF4, BATF and RORyt.
O-GlcNAc regulates CD4+ T cell differentiation
Authors: Machacek Miranda E , Slawson Chad , Fields Patrick 
Published: January 2023

Abstract
Chronic inflammation is a feature of diabetes and obesity and enhances the risk of atherosclerosis and cancer. Specifically, proinflammatory Th1 and Th17 CD4+ T cells are increased in metabolic diseases. However, a clear molecular mechanism linking metabolic changes with proinflammatory T cells is lacking. We hypothesize that elevated levels of O-linked β-N-acetylglucosamine (O-GlcNAc), a post-translational modification of nuclear and cytoplasmic proteins, promotes proinflammatory CD4+ T cell differentiation. Since production of O-GlcNAc involves input from carbohydrate, amino acid, fatty acid, and nucleic acid metabolism, the modification acts as a general sensor of a cell’s nutritional status. To investigate O-GlcNAc’s role, we cultured mouse splenic CD4+ T cells with Thiamet-G (TMG), a selective inhibitor of the enzyme that removes O-GlcNAc (O-GlcNAcase, OGA), before activating with anti-CD3 and anti-CD28 under permissive Th0 conditions. We find a significant two-fold increase in protein and transcript levels of IL-17A, the eponymous Th17 cytokine. Intracellular cytokine staining shows two-fold increases in IFNγ+ cells, IL-17+ cells, and IFNγ+IL-17+ cells. Phosphorylation of STAT3 and STAT4, the transcriptionally active form of STATs which define the Th17 and Th1 lineage programs respectively, is increased in TMG-treated cells within 10 minutes of T cell receptor activation. Collectively, our data suggest that elevated O-GlcNAc levels prime Th17, Th1, and Th1-like Th17 CD4+ T cell differentiation by increasing activated STAT3 and STAT4. Further study into the molecular mechanism of how O-GlcNAcylation promotes proinflammatory T cells may provide insight into how nutritional excess exacerbates inflammation.
A dominant function of transcription factor Foxo1 in the development of Th9 and IL-9-producing T cells
Authors: Awasthi Amit , Malik Sakshi , Sadhu Srikanth 
Published: January 2023

Abstract
Interleukin 9 (IL-9), a pleiotropic cytokine of common γ-chain cytokine receptor family, plays a crucial role in allergic inflammation, autoimmunity and immunity to extracellular pathogens. Recent identification of anti-tumor function of IL-9 makes it an attractive target for anti-tumor therapy. Although Th2, Th17 cells and Foxp3+ Treg cells were shown to produce IL-9, more specialized IL-9-producing Th9 cells were identified as a distinct subset of Th cells that are proinflammatory in vivo. The master transcription factors that regulates IL-9 production in Th2, Th9 and Th17 cells has not been identified, although IRF-4, PU.1, Batf and IRF1 were shown to be essential for IL-9 induction in Th9 cells. Here we have identified Foxo1, a forkhead family transcription factor, predominantly required for the induction of IL-9 in Th9 and Th17 cells. We further identified AKT, an upstream kinase that regulates IL-9 induction in Th1, Th9 and Th17 cells via Foxo1. In addition, c-Jun N-terminal kinase (JNK), a MAPK (Mitogen Activated Protein kinase) enhanced IL-9 induction in Th9 cells via Foxo1. Chromatin Immunoprecipitation (Chip) identified a direct physical association of Foxo1 with IL-9 and IRF4 promoters. Furthermore, loss of Foxo1 suppressed IL-9 production in Th9 and Th17 cells. In fact, Foxo1 act as a transcriptional switch, which exclusively suppress IL-9 induction in Th17 cells while enhancing IL-17 and Th17 cells development. In Th9 mediated asthma model, Foxo1 inhibition substantially ameliorated allergic inflammation and IL-9 induction. Our findings thus identify Foxo1 as a master transcription factor in controlling the development of Th9 and IL-9-producing Th cells.
Optimum differentiation conditions of lactoferrin/TGFβ-caused inducible regulatory T cells
Authors: Kim Pyeung-Hyeun , Kim Sun-Jin , Seo Goo-Young , Kim Hyeon-Jin , Kwon Bo-Eun , Ko Hyun-Jeong , Rhee Ki-Jong , Kim Woan-Sub 
Published: January 2023

Abstract
TGF-β1 and retinoic acid (RA) are well known to stimulate naïve T cells to differentiate into regulatory T cells (Tregs). In the present study, we found that, as assessed by Foxp3 expression, lactoferrin (LF) not only promotes the TGFβ/RA-mediated Treg differentiation but it also induces Treg differentiation by itself. Furthermore, LF in combination with TGF-β1 powerfully enhanced Foxp3 expression at the transcriptional and protein levels. In this, our extensive kinetic study led the maximum Foxp3 expression within 36 h of culture. These Foxp3+ CD4+T cells strongly suppressed the proliferation of CD4+T cells activated with αCD3 and αCD28 Ab. Finally, phenotypes of these Foxp3+ CD4+T cells were CD44hi CD62Lhi, T-betlo, IFN-γlo, GATA3lo, and IL-4lo. Our optimized Treg differentiation condition would be useful when Treg adoptive transfer is required for various immunosuppressive therapies.
IL-12 and IFN-I differentially regulate secondary CD4+ T cell responses.
Authors: Meek Stephanie M , Kim Chulwoo , Williams Matthew A 
Published: January 2023

Abstract
Upon re-exposure to antigen, memory T cells give rise to secondary effector responses that enhance clearance and immune protection. Additionally, secondary activation often boosts the number of memory T cells. Therefore, understanding the parameters that control secondary T cell differentiation and function is critical. We report key roles for IL-12 and Type 1 I IFN (IFN-I) in controlling secondary T cell activation, differentiation and memory formation. While IL-12 was required for the development of secondary effector cells with high functional avidity, as well as the optimal formation of secondary T cell memory, IFN-I inhibited both of these features. Within 24 hours of secondary challenge we observed CD4+ memory T cell-dependent increases in serum IL-12 and IFNγ. While IL-12 neutralization resulted in a predictable reduction of IFNγ, blockade of the IFNα/β receptor (IFNAR) induced significantly higher expression of IL-12, IFNγ and IL-6. The effect was indirect, as rechallenge of WT CD4+ memory T cells in an IFNAR-deficient host resulted in increased functional avidity of secondary effector CD4+ T cells. In contrast, secondary T cell expansion was partly curtailed in these hosts, indicating both stimulatory and inhibitory effects for IFN-I in the setting of secondary challenge. Several immunoregulatory functions for IFN-I have been reported, including induction of IL-10. In support of this, secondary challenge of WT CD4+ memory T cells in IL-10-deficient hosts resulted in enhanced secondary effector function. These findings highlight a key role for IFN-I in regulating secondary CD4+ T cell differentiation and suggest potential therapeutic approaches that preferentially target its immunoregulatory functions.
Nrf2 activation skews murine and human CD4 T cell differentiation towards a Th2 phenotype
Authors: Turley Alexandra E , Zagorski Joseph Ward , Klaassen Curtis , Fields Patrick E , Rockwell Cheryl Elizabeth 
Published: January 2023

Abstract
CD4 T cell differentiation is a critical part of the adaptive immune response during which CD4 T cells adapt a response to a specific pathogen. Nuclear factor erythroid-derived 2 like-2 (Nrf2) is a cell-stress responsive transcription factor that regulates a battery of antioxidant, detoxification, and cytoprotective genes. Nrf2 is activated by stressors such as reactive oxygen species and electrophilic xenobiotics, including tert-butylhydroquinone (tBHQ), a commonly used food preservative. Nrf2 has been shown to be immunomodulatory: Nrf2 null mice are more susceptible to inflammatory stimuli such as sepsis, lung injury, and experimental autoimmune encephalomyelitis. In addition, Nrf2 has been shown to modulate dendritic cell and macrophage function, however, the role of Nrf2 in CD4 T cells remains only partially characterized. Thus, the goal of the present studies is to determine the role of Nrf2 in CD4 T cell differentiation in primary human and mouse CD4 T cells. Treatment with the Nrf2 activator tBHQ increased production of the Th2 cytokines IL-4, IL-5, and IL-13 in CD4 T cells isolated from wild-type, but not Nrf2-null mice, and decreased production of the Th1 cytokine IFNγ. tBHQ increased GATA-3 and decreased T-bet DNA binding in wild type but not Nrf2-null mice. In primary human CD4 T cells, tBHQ treatment increased production of the cytokines IL-4, IL-5, and IL-13, and had no effect on IFNγ production upon restimulation. Collectively, these data suggest that Nrf2 activation promotes Th2 differentiation of primary human and mouse CD4 T cells. (Funded by NIH grants ES018885 and ES007255).
High rates of cross-reactivity among apparently unrelated specificities shape antigen-specific T cell receptor repertoires
Authors: Thomas Paul Glyndwr , Dash Pradyot , Hertz Tomer , Gartland Andrew , Bradley Philip 
Published: January 2023

Abstract
We have analyzed several thousand antigen-specific T cell receptor repertoires from multiple animals infected with influenza virus and/or murine cytomegalovirus (mCMV). Insights into the overall structure of antigen-specific repertoire landscapes towards 7 different specificities were generated from single cell paired TCR αβ sequencing. In addition to characterization of repertoire features such as diversity, clonal structure, convergent recombination, and key deterministic features of antigen-specificity, we observed a surprisingly high rate of single or dual chain sharing between otherwise unrelated responses. These shared receptors were often observed across multiple animals in independent experiments. However, sharing appeared more likely to occur in animals where the two epitopes were presented simultaneously. Cloning and expression of these unique specificities has allowed further receptor characterization. Additional data indicate that some combinations of co-presented epitopes result in broader repertoires recruited to one or both epitopes. In summary, T cell receptors have a significant propensity for cross-reactivity across otherwise unrelated specificities, an effect that appears to be driven by co-presentation and substantially shapes the magnitude and diversity of antigen-specific repertoires.
Aging converts innate B1a cells into potentially pathogenic 4BL cells that induce cytolytic CD8+T cells.
Authors: Biragyn Arya , Lee-Chang Catalina , Bodogai Monica 
Published: January 2023

Abstract
Immune system becomes dysregulated in aging of mammals affecting both myeloid and lymphoid immune cell compartments. Compounded with a life-long antigenic exposure, changes in T cells and increased half-life of mature B cells, conventional B2 cells are enriched for antigen-experienced memory and mature cells at the expense of naive B cells. However, the role of aging on innate B1a cells, the key produces natural antibody to pathogens and endogenous antigens, is not known and is assumed to be negligible. Here, we question this assumption by providing evidence that B1a cells become converted into 4BL cells, the 4-1BBL+MHC class-IHiCD86Hi B cells that induce cytolytic granzyme B (GrB)-expressing CD8+T cells upon aging of humans, macaques and mice 1. This conversion is mediated by aging CD11b+ myeloid cells, which induce a chain of activating events in B1a cells. First, B1a cells express 4-1BBL and IFNgR1 to be used for up regulation of membrane TNFa (mTNFa) and CD86 expression, respectively. Then, using mTNFa, 4BL cells induce GrB expression in CD8+T cells via targeting TNFR2 while providing co-stimulation with CD86. Thus, for the first time, we report that B1a cells become dysregulated upon aging. They lose ability to support tumor growth and gain a new function – the induction of potentially antitumor and autoimmune CD8+T cells. This work was entirely supported by the Intramural Research Program, NIA/NIH.1.