bluuebunny/crossref_metadata_2025_split huggingface dataset:
zVAD-induced necroptosis in TLR3/4-stimulated macrophages involves TRIF-dependent interferon signaling pathway and ROS-dependent autophagy
Authors: Lin Wan Wan 
Published: January 2023

Abstract
Depending on the cell types, caspase inhibition might lead to autophagy. In macrophages, necroptosis and autophagic cell death involving reactive oxygen species (ROS) production can be induced by co-treatment with lipopolysaccharide (LPS) and a cell-permeable pan-caspase peptide inhibitor zVAD. Here we elucidated the signaling pathways and molecular mechanisms underlying this process. First we confirmed that primary bone marrow-derived macrophages treated with LPS plus zVAD or polyIC plus zVAD display cell death with necrotic and autophagic features. Although zVAD did not affect LPS- or polyIC-induced IKK, JNK and p38 activation, it enhanced IRF3 and STAT1 activation as well as type I IFN gene and protein expression. Interestingly these enhancing actions of zVAD were inhibited by necrostatin-1. Our data further support the involvement of autocrine IFNs action in ROS-dependent necroptosis, as cell death induced by TLR ligands with zVAD co-treatment was prevented by ROS scavenger BHA, neutralizing antibody targeting IFNR and JAK inhibitor AZD1480. Consistently, LPS plus zVAD-elicited ROS production was inhibited by necrostatin-1, IFNR antibody and AZD1480. Accordingly, both cell death, LC3II accumulation and ROS production induced by TLR ligands plus zVAD were abrogated in STAT1 knockout macrophages. Taken together, we propose a new molecular basis for TLR-mediated necroptosis under caspase inhibition in macrophages, which involves the enhanced TRIF-RIP1-IRF3 signaling pathway and autocrine IFNs-IFNR-JAK-STAT1 action, leading to ROS-dependent autophagic cell death.
Comparison of the TLR7 and TLR9 innate immune signaling pathways in african green monkeys and rhesus macaques
Authors: Cox Kara S. , Wang I-Ming , Nefedov Alexey , Zhang Xiaohua Douglas , Dubey Sheri , Bett Andrew , Casimiro Danilio , Mandl Judith , Feinberg Mark B. 
Published: January 2023

Abstract
Innate immunity is an evolutionary mechanism which is involved in the initial detection of pathogens and stimulates the first line of host defense. The Toll-like receptor (TLR) family has been the most extensively studied innate immune pathway and it has been shown that TLRs can be activated in response to virtually any microbe which invades the host. These innate immune responses play a critical role in the development of pathogen-specific adaptive immune responses and disease pathology and are targeted by the use of adjuvants in modern vaccines. Importantly, divergent TLR7 and TLR9 signaling pathways between rhesus macaques and sooty mangabeys have been shown to distinguish between pathogenic and nonpathogenic AIDS virus infections in those species. Therefore, it is important to understand the TLR signaling pathways of non-human primate (NHP) species that are currently used for infectious disease and vaccine research. In the present study, we administered defined TLR7 and TLR9 agonists to two distinct NHP species, african green monkeys and rhesus macaques. We evaluated B cell, T cell, NK cell, monocyte, plasmacytoid dendritic cell and myeloid dendritic cell activation at 0, 24, 72 and 168 hours after dosing. Gene expression profiling and full pathway analysis was also evaluated to illuminate fundamental aspects of innate immune responses that underlie the mechanism of action of TLR-agonist adjuvants in these two NHP species.
Catalase deficiency in thymic stromal cells promotes key stromal functions in the young, steady state mouse thymus
Authors: Semwal Manpreet Kaur , Xiao Yangming , Venables Thomas , Griffith Ann V 
Published: January 2023

Abstract
T lymphocytes develop in the thymus, where mutually inductive signaling between lymphoid progenitors and thymic stromal cells directs the progenitors along a well-characterized program of differentiation. However, the biology of the stromal cells comprising the lymphopoietic thymic microenvironment remains relatively under-characterized because stromal cells are rare and difficult to isolate. Using a deconvolution technique to study gene expression essentially in situ, we previously identified a deficiency in the peroxide quenching enzyme catalase (CAT) in thymic stromal cells, and found that CAT deficiency results in high reactive oxygen (ROS) levels in this population, eventually leading to thymic atrophy. Here, we address the possibility that high ROS levels serve physiological functions in stromal cells in the young, steady state thymus. Our preliminary data indicate that when catalase deficiency is complemented by overexpression targeted to mitochondria in transgenic mice (mCAT Tg), both ROS levels and stromal function are diminished in young mice relative to non-transgenic littermates. We find evidence of diminished tissue-restricted antigen (TRA) expression and autophagy in mCAT Tg mice, both of which are critical for establishing a self-tolerant T cell repertoire. We propose that a high ROS environment in stromal cells promotes promiscuous gene expression and autophagy critical for stromal induction of T cell tolerance in the young thymus, while accumulated oxidative damage ultimately undermines healthy thymus function.
Alteration of T cell Repertoire in insulin-sensitive tissues following the onset of Type 2 diabetes
Authors: Hernandez Jeniffer B , Yoon Young-Sil , Montminy Marc 
Published: January 2023

Abstract
The CREB/CRTC2 pathway functions importantly in the liver, where it promotes fasting glucose balance by upregulating the gluconeogenic program. More recently CREB has emerged as an important regulator of immune function. We have shown that the CREB/CRTC2 pathway modulates autoimmune disease by promoting differentiation of the pro-inflammatory T cell, Th17. We are curious to determine if CRTC2 plays a role in the chronic inflammatory state during obesity that contributes to the development of insulin resistance. One of the consequences of insulin resistance is hyperglycemia, therefore we set out to determine what the effect of culturing T cells under high glucose concentrations would be. Interestingly, T cells cultured under high glucose conditions had a decreased ability to differentiate into Th17 cells compared to T cells cultured under normal glucose conditions. CRTC2-deficient T cells had a greater decrease in their ability to differentiate into Th17 cells in high glucose concentrations compared to wildtype T cells. To determine if the T cell repertoire is altered in insulin-sensitive tissues following diet induced Type 2 diabetes, wildtype mice were fed a normal chow or high fat diet for 20 weeks. Consistent with our in vitro findings, lean mice had a greater number of IL17+ T cells compare to obese mice. Our current findings suggest that IL17+ T cells may have a beneficial role instead of a role in promoting the chronic inflammatory state during obesity that contributes to the development of insulin resistance.
CCR7+ naive iNKT serve as precursors for iNKT effector subsets and distinct mechanisms are involved in their thymic retention
Authors: Wang Haiguang , Lee You Jeong , Jameson Stephen C. , Hogquist Kristin A. 
Published: January 2023

Abstract
Invariant natural killer T cells (iNKT) are CD1d restricted, lipid recognizing αβ T cells that modulate immunity under various contexts. iNKT are comprised of distinct effector subsets, NKT1, NKT2 and NKT17, characterized by long term retention in the thymus. However, the developmental steps of iNKT cell effector differentiation have been controversial, and mechanisms underlying their thymic retention are unclear. Specifically, the markers historically used to define stage 1 and 2 precursors also include mature effector NKT2 and NKT17 cells. Using RNAseq, we identified CCR7 as a candidate marker for undifferentiatied or naïve iNKT precursor. We demonstrate here that CCR7+ iNKT cells, distinguished from stage 0 iNKT by low CD24 expression, migrate from thymic cortex to medulla to give rise to iNKT effector subsets. CCR7+ iNKT express higher Rag2GFP, indicating they are “younger” than other thymic iNKT cells. Moreover, iNKT recent thymic emigrants in the periphery, identified by intrathymic labeling, are predominantly CCR7+ iNKT that express both Rag2GFP and KLF2, and are Qa2 negative. Busulfan chimeras confirmed that CCR7+ naive iNKT emigrate from thymus well before the accumulation of thymic effector iNKT cells. Type I and II interferon signals synergistically up-regulate CD69 in NKT1, and contribute to their retention in thymus. NKT17 highly express CD103 that might be critical for their thymic retention. Although it remains unclear how NKT2 are retained, their selective expression of IL-4 and RANK ligand influence effector CD8 T cell, as well as thymic DC and medullary epithelial cells (mTEC) development. Our findings provide novel insights into the developmental pathway of iNKT cells and the mechanisms of their thymic retention.
TRAF1 negatively regulates C-type lectin receptor-induced proinflammatory response to fungal infection
Authors: Xiao Hui , Deng Zihou , Watts Tania H 
Published: January 2023

Abstract
Fungal infections pose serious health threat worldwide, causing severe mucosal and systemic candidiasis in elderly people, AIDS patients and organ recipients. Through sensing fungal cell-wall components b-glucan and mannan, C-type lectin receptors (CLRs) dectin-1 and dectin-2/3 play pivotal role in the induction of anti-fungal innate and adaptive immune responses. However, the regulatory mechanisms of CLR signaling remain to be better understood. Indeed, our previous work demonstrated that the protein tyrosine phosphatase SHP-2 acts as a positive regulator of CLR-induced signaling, and thus plays a critical role in DCs to promote anti-fungal Th17 response. In this study, we found that fungus-elicited CLR signals are also stringently controlled by negative regulation. Upon C. albicans infection, TRAF1 was highly induced in skin, lung and kidney. Elevated TRAF1 expression was also detected in macrophages and DCs stimulated by dectin-1 and dectin-2/3 ligands, respectively. Mechanistically, TRAF1 acted as a feed-back negative regulator critically controlling the induction of proinflammatory genes, such as Cxcl1 and Tnf, in response to fungal infection. Consistently, TRAF1-deficient mice exhibited increased neutrophil-infiltration, highly efficient fungal eradication and ameliorated tissue damage, culminating on improved host defense and better survival. Taken together, this study identified a new feed-back regulatory mechanism by which CLRs regulate anti-fungal proinflammatory response.
The life cycle stages of the opportunistic fungal pathogen Pneumocystis murina provoke a differential immune response in antigen-presenting cells
Authors: Evans Heather Marie , Garvy Beth A 
Published: January 2023

Abstract
Pneumocystis species are opportunistic fungal pathogens that cause severe pneumonia in immunocompromised hosts. The life cycle of Pneumocystis species consists of a trophic stage and an ascus-like cystic stage. Our lab has published data demonstrating that cysts stimulate NF-κB translocation in alveolar macrophages, but the trophic form does not. Here, we demonstrate that infection of wild-type adult mice with a normal mixture of trophic and cystic P. murina life forms elicits a more robust innate immune response in the alveolar spaces and lung parenchyma than infection with the trophic form alone. To determine the pattern recognition receptors that bind trophozoites and cysts, we examined expression of C-type lectin receptors on lung CD11c+ dendritic cells in vivo. Infection with a mixture of trophozoites and cysts resulted in the upregulation of dectin-1 and mannose receptor, while infection with trophozoites alone resulted in upregulation of dectin-2, DEC-205 and mannose receptor. In addition, we demonstrate that bone marrow-derived dendritic cells stimulated with a mixture of trophozoites and cysts produced the proinflammatory cytokines IL-1β and IL-6. In contrast, exposure to trophozoites suppressed β-glucan-induced IL-1β, IL-6, and TNFα production by bone marrow-derived dendritic cells. A targeted gene expression assay is being used to evaluate gene expression in dendritic cells following stimulation with trophozoites alone or a mixture of trophozoites and cysts. We propose that trophozoites suppress β-glucan-signaling, but are sufficient for stimulating protective responses in immunocompetent individuals.
Examining the function of chemokine receptor deficient-monocytes during infection with Nippostrongylus brasiliensis
Authors: Barnes Mark A , Wang Spencer , Lo David , Nair Meera G 
Published: January 2023

Abstract
Nippostrongylus brasiliensis (Nb) is a murine helminth that acutely infects the lungs and the small intestine, and induces a strong Th2 immune response, which includes contributions from innate immune cells such as monocytes. CCR2, the receptor for MCP1, which is expressed primarily on monocytes, was predictably important for monocyte recruitment during Nb infection. However, it was also shown to be necessary to control hemorrhaging as CCR2−/− mice had more blood in the bronchoalveolar lavage fluid compared to wild-type (WT) mice. In addition, CCR2−/− mice produced higher egg burden and more viable worms based on parasite ATP assays. Signaling through CX3CR1, another receptor expressed on monocytes provoked the opposite phenotype. CX3CR1 was not crucial for cellular recruitment after infection, but Nb from CX3CR1−/− mice produced less eggs and were less viable than Nb from WT mice. To investigate potential mechanisms by which monocytes influence worm viability, infective stage Nb (L3) were co-cultured with sorted Ly6c+ monocytes from CX3CR1 WT or knockout (ko) mice. After 5 days in culture, Nb incubated with ko Ly6c+ cells were less motile than Nb cultured with WT Ly6c+ cells. Taken together, these data indicate that CCR2-dependent infiltrating monocytes control inflammation and promote worm killing, while CX3CR1 signaling in monocytes promotes worm viability potentially by influencing worm motility.
Anti-Fungal Functional Tc17 Cells Persist as Long-Lasting Memory Without Plasticity Towards IFNγ
Authors: Nanjappa Somashekarappa Gowda , McDermott Andrew , Fites Scott , Klein Bruce 
Published: January 2023

Abstract
Memory homeostasis of Th1/Tc1 cells is well characterized, whereas memory Th17-cell homeostasis, persistence and plasticity are debated. We have shown that IL-17A-producing CD8+ T-cells (Tc17) are necessary for vaccine-induced fungal immunity in CD4+ T-cell compromised hosts. Here, we systematically evaluated persistence, fidelity, plasticity and functional role in immunity of anti-fungal Tc17 cells using IL-17A fate-mapping reporter mice. We show that Tc17 cells stably maintained as functional bona fide IL-17A producing memory cells, with little plasticity towards IFNγ, even in the absence of vaccine antigen. Memory Tc17 cells stably and progressively improved in their production of multiple Tc1 cytokines but not IFNγ, and contributed for IL-17A-dependent vaccine resistance. Memory Tc17 cells were canonical CD8+ T cells portraying a set of phenotypic attributes that were distinct from Tc1 cells while remaining Ror(γ)hi, T-betlo and EOMESlo. Interestingly, in contrast to Tc1, memory Tc17 cells expressed lower levels of anti-apoptotic factors Bcl-1, Bcl-xL and MCL-1. However, basal homeostatic proliferation of memory Tc17 cells was significantly higher than Tc1 cells. Finally, we unraveled a dichotomous role of HIF-1α for effector vs memory Tc1 and Tc17 cells, where HIF-1α was essential for expression of IL-17A in memory cells while it was required for expression of IFNγ in effector cells.
TRAF6 in dendritic cell plays a key role to control immune response to dietary antigens
Authors: Han Daehee , Choi Yongwon , Surh Charles D 
Published: January 2023

Abstract
TRAF6 is critical for Toll-like receptor (TLR)-mediated activation of dendritic cells (DCs). Recently, by studying mice DC-specific deletion of TRAF6 (TRAF6ΔDC) we have reported that TRAF6 expression in DCs is important to prevent a spontaneous Th2-associated gut inflammatory disease. To formally demonstrate an involvement of commensal microbiota, we have generated TRAF6ΔDC bone marrow chimeras under germ-free (GF) conditions. Unexpectedly, the Th2-associated disease in GF TRAF6ΔDC chimeras was exacerbated compared with TRAF6ΔDC chimeras generated under conventional conditions. Finally, to test whether the Th2-associate disease is driven by dietary antigens (Ags), we established TRAF6ΔDC bone marrow chimeras in “Ag-free” mice, in which GF mice are raised with a chemically-defined elemental diet devoid of macromolecules. Strikingly, the induction of a spontaneous intestinal Th2-associated inflammatory disease was dramatically averted in “Ag-free” TRAF6ΔDC chimeras, indicating that TRAF6 expression in DCs is essential to establish and/or maintain oral tolerance to dietary Ags.
Anti-α4β7 mAb prevents MAdCAM-1-mediated activation and HIV replication in CD4+ T cells
Authors: Waliszewski Mia , Nawaz Fatima , Cicala Claudia , Ray Jocelyn , Olowojesiku Ronke , Perrone Ian , Wei Danlan , Jelicic Katija , Van Ryk Donald , Ansari Aftab Ahmed , Fauci Anthony S , Arthos James 
Published: January 2023

Abstract
HIV-1 preferentially infects α4β7+ CD4+ T cells, causing irreversible depletion of these cells in gut-associated lymphoid tissue (GALT) during the acute phase of infection. α4β7 mediates homing of CD4+ T cells to GALT through an interaction with mucosal addressin cell adhesion molecule-1 (MAdCAM-1), expressed on gut endothelial venules. In a rhesus macaque model of HIV transmission, administration of an anti-α4β7 mAb protected GALT from SIV infection. The mechanism(s) underlying this protection are poorly understood. We hypothesized that the anti-α4β7 mAb prevents MAdCAM mediated co-stimulation in a manner that could contribute to the protection that we observed. We determined that costimulation of CD4+ T cells through MAdCAM could support both proliferation of CD4+ T cells and viral replication in a manner that was inhibited by the anti-α4β7 mAb. In addition, MAdCAM costimulation induced the up-regulation of Ki-67, CD38 and CXCR5. Interestingly, we found that MAdCAM could induce the expression of CD45RO on naïve CD4+ T cells in the absence of proliferation, suggesting that this mode of costimulation is unique. These results indicate that costimulation of CD4+ T cells via MAdCAM provides a signal that promotes replication of HIV. Moreover, an anti-α4β7 mAb that interferes with the binding of MAdCAM to α4β7 inhibits both proliferation and viral replication, providing a potential mechanism for the capacity of this mAb to protect rhesus macaques from infection by SIV.
Delay in CD8 T-cell priming impairs viral control after vaginal LCMV transmission
Authors: Khan Shahzada , Woodruff Erik M. , Trapecar Martin , Sanjabi Shomyseh 
Published: January 2023

Abstract
Parameters required for eliciting CD8-T-cell-mediated immunity in the tolerogenic environment of female reproductive tract (FRT) are not well understood. We established a mouse model of intravaginal infection with acute lymphocytic choriomeningitis virus (LCMV) and showed that, compared to systemic infection, CD8-T-cell-mediated protective immune response was delayed in the FRT. After i.vag. LCMV infection, live virus is transmitted to the draining iliac lymph node (iLN) from the lower female reproductive tract (LFRT), which helps to prime virus-specific CD8 T cells in the iLN and restricts further systemic spread of the virus. However, T-cell priming in the iLN of i.vag. mice is delayed compared to that in i.p. infected mice, causing a delay in the appearance of effector CD8 T cells in the LFRT. This delayed CD8 T-cell response in LFRT provides LCMV a window of opportunity to replicate robustly in this immune privileged site. Mechanistically, the delay in CD8 T-cell priming is due to suboptimal activation of LFRT migratory DCs, which require further maturation upon migration into the iLN. As a potential cause of the suboptimal DC activation, we found that LFRT expresses limited steady-state levels of viral RNA-sensing pattern-recognition-receptors and elicits minimal induction of interferons and other inflammatory mediators required for anti-viral immunity. These findings provide a mechanistic explanation for the cause of the delay in CD8 T-cell activation after intravaginal viral infection and emphasize the notion that successful vaccination against RNA viruses may require adjuvants that elicit a stronger innate immune response than that provided by live viruses.
Inflammatory signals control human MAIT cell effector function
Authors: Slichter Chloe K , McDavid Andrew , Miller Hannah , Finak Greg , Seymour Brenda , McNevin John , Diaz Gabriela , Czartoski Julie , McElrath Margaret J , Gottardo Raphael , Prlic Martin 
Published: January 2023

Abstract
Mucosal-associated invariant T (MAIT) cells recognize bacterial metabolites presented on MR1 via their semi-invariant T cell receptor (TCR). MAIT cells are a potent effector population located in tissues that are constantly exposed to the microbiome. This raises the question how MAIT cell activation is regulated to avoid unwanted responses to microbiome-derived metabolites. To address this we dissected the MAIT cell response to TCR- and cytokine-mediated signals. We found that stimulating the MAIT TCR in the absence of inflammatory cytokines was not sufficient to induce effector function such as granzyme B and interferon-g expression. Inflammatory signals acting directly on MAIT cells were absolutely necessary to allow for TCR-mediated acquisition of effector function. Importantly, MAIT cells are not generally hyporesponsive to TCR-mediated signals as TCR stimulation in the absence of inflammation elicited a distinct chemokine response.
Single-cell gene expression analysis of MAIT cells isolated from healthy human mucosal tissue revealed increased expression of inflammatory genes compared to their counterparts in the blood, indicating that provided the proper signals mucosal MAIT cells are poised to respond rapidly to infection. Importantly, MAIT cells in the mucosa do not produce inflammatory cytokines directly ex-vivo, despite expressing higher levels of inflammatory transcript.
We propose a novel model in which the strict dependence of TCR-mediated signals on pro-inflammatory cytokines to induce effector function represents a MAIT cell-intrinsic mechanism to prevent unwanted responses to commensal bacteria-derived bacterial metabolites, while allowing potent effector responses following infection.