bluuebunny/crossref_metadata_2025_split huggingface dataset:
Early microbial changes affect mucosal immunity in autoimmune arthritis
Authors: Kuhn Kristi , Hendrickson Jason D. , Mehta Gaurav , Adhikari Sumitra , Banda Nirmal , Robertson Charles E. , Frank Daniel N. , Demoruelle M. Kristen , Deane Kevin D. 
Published: January 2023

Abstract
Multiple lines of evidence now suggest that autoimmune disease may result from microbial-mucosal interactions. Microbial dysbiosis occurs in new onset seropositive rheumatoid arthritis (RA); and during the preclinical phase of RA, there is an expansion of mucosal autoantibodies and plasmablasts. These findings strongly suggest that a mucosal site may drive the initial break in tolerance that leads to RA. Using the murine collagen-induced arthritis model of RA, we find that microbiome diversity changes quickly after immunization with bovine type II collagen, at the time when disease-related autoantibodies develop, but before clinical CIA is evident. Significant alterations in taxa clustered in Clostridia families occur in CIA. Interestingly, using IgA-seq in human at-risk for RA study groups we find that those subjects with autoantibodies have similar alterations in Clostridia families. Furthermore, during the development of murine CIA, increased intestinal permeability and altered cytokine profiles paralleled disease development and microbiota alterations. Taken together, these data suggest a model in which early microbial alterations stimulate mucosal immune responses that drive the development of pathogenic autoantibodies. Future studies are aimed at identifying specific bacterial species and elucidating the pathway by which they stimulate autoantibody production.
Langerhans cells and CD11b+ dermal dendritic cells are involved in skin Treg generation
Authors: Tordesillas Leticia , Mondoulet Lucie , Benhamou Pierre-Henri , Sampson Hugh A , Berin M. Cecilia 
Published: January 2023

Abstract
Antigen applied to the skin can induce immune tolerance in naïve mice and can be used as epicutaneous immunotherapy (EPIT) to treat experimental food allergy. In previous unpublished work, we have shown that EPIT induces Tregs, including a population of intestinal-homing LAP+ Tregs that can suppress mast cell activation and anaphylaxis. In this extension of that work, our goal was to determine how dendritic cells (DCs) in the skin contribute to the induction of LAP+ Tregs. Epicutaneous antigen exposure of mice that have received DO11.10 T cells with Viaskin®-OVA patches for 48 h induced OVA-specific LAP+ Tregs to a similar extent in naïve and sensitized mice. Therefore all additional studies were done in naïve mice. FACS sorting of DC subsets from skin-draining lymph nodes of Viaskin®-treated mice and then co-cultured with DO11.10 T cells demonstrated that CD11b+ CD103− dermal DCs and CD11b+EpCAM+ Langerhans cells (LCs) were both capable of antigen capture and presentation to CD4+ T cells, as well as Treg generation. PDL2 was found on both subsets and effectively discriminated between cells with and without antigen capture and presentation capacity. PDL2+ DCs presented a more mature phenotype, with higher expression of MHCII, CD86 and CD80 than PDL2− DCs. PDL2+ LCs and PDL2+ CD11b+ DCs were sorted separately and expression of regulatory molecules (GM-CSF, IL-27, IL-10, TGF-b, ALDH2 and IDO) were assessed by RT-PCR. PDL2+ LCs uniquely expressed IL-27, while PDL2+ CD11b+ DCs were enriched for ALDH2, which was then confirmed by flow cytometry. In vivo depletion of LCs using anti-CSF1 did not influence generation of Tregs in vivo. These results indicate that induction of Tregs through the skin is not restricted to one DC subset.
DMBA specific induces Treg proliferation in draining lymph node
Authors: Tang Hua , Kang Li , Cheng Yi , Wang Meixiang , Gao Jiming , Zhang Shanlong , Song Wengang 
Published: January 2023

Abstract
DMBA, a carcinogenic agent which can induce organism tumor production, was used as a tumor inducer to analyze the draining lymph node T cell development in the skin of mice. The results indicated that antigen-specific T cell proliferation was significantly increased in draining lymph node after DMBA treatment, and CD4+ Foxp3+ Treg measurement results showed that the percentage of Treg increased. Compared with the treatment of acetone, OVA or CpG the proliferation of CD4+ Foxp3+ Treg was carcinogenic agent dependence. More importantly, CD4+ Foxp3+ Helios+ T proliferation assay and CD4+ Foxp3-GFP+ T and CD4+ Foxp3-GFP− T adoptively transfer result indicated the proliferation of Treg was from nTreg but not iTreg. Gene chips assay showed that the expression of energy metabolism relative protein, such as Myo1f and Myl4, and cellular growth regulation protein, such as Anxa2, was significantly up-regulated, which provide a potential target to suppress Treg proliferation during tumor development.
This study was supported by the National Natural Science Foundation of China (81272315)
Autophagy-dependent TIGIT+ Treg are critical for the maintenance of tolerance
Authors: MacDonald Kelli PA , Le Texier Laetitia , Leveque-ElMouttie Lucie , Lineburg Katie , Nicholls Jemma , Guimaraes Fernando Souza-Fonseca , Alexander Kylie , Clouston Andrew , Blazar Bruce R , Hill Geoff R 
Published: January 2023

Abstract
Regulatory T cells (Treg) play a crucial role in the maintenance of peripheral tolerance. Quantitative and/or qualitative defects in Treg result in diseases such as autoimmunity and graft-versus-host disease (GVHD), a serious complication of bone marrow transplantation (BMT). We recently reported that G-CSF mobilisation of stem cells in donor mice increases autophagy related genes in Treg and it is associated with an improved GVHD outcome after BMT. Autophagy is a self-degradative process for cytosolic components which promotes cell homeostasis and survival. Here, we demonstrate that the lineage-specific disruption of autophagy within FoxP3+ Treg (Atg7fl/fl.FoxP3cre+ mice) resulted in a profound loss of Treg within the bone marrow (BM). This resulted in dysregulated effector T cell activation and expansion, and in aged mice, the development of enterocolitis and severe scleroderma. We show that the BM compartment is highly enriched in TIGIT+ Treg and that this subset is differentially lost in the absence of autophagy. Moreover, G-CSF administration to naive mice results in the mobilization of BM TIGIT+ Treg explaining the autophagy signature of peripheral Treg in G-CSF treated mice. Importantly, lethally irradiated B6D2F1 recipients of splenic grafts from G-CSF mobilized B6.Atg7fl/fl.FoxP3cre+ donors failed to reconstitute the Treg compartment within the BM. This resulted in GVHD exacerbation and reduced survival compared to recipients of B6.WT.FoxP3cre+ grafts. Collectively, these data indicate that autophagy-dependent TIGIT+ Treg in the BM are critical for the maintenance of tolerance and to control GVHD; thus the induction of autophagy may represent an attractive immune-restorative therapeutic strategy.
Antigen-specific induced T regulatory cells (iTregs) inhibit dendritic cell (DC) function by capturing peptide-MHCII complexes from the DC surface
Authors: Akkaya Billur , Akkaya Munir , Holstein Amanda H , Kamenyeva Olena , Kabat Juraj , Shevach Ethan M 
Published: January 2023

Abstract
Tregs are critical mediators of peripheral immune tolerance. A majority of the mechanisms utilized by antigen-specific Tregs to suppress immune responses, suggest an initial inhibition of dendritic cell (DC) function that results in diminished activation of T effector cells (Teff) specific for the homologous target as well as diminished activation of other antigen-specific Teff cells that recognize different antigens presented by the same DC (bystander suppression). In an adoptive transfer model in vivo, we demonstrated that OTII transgenic iTregs specific for Ovalbumin323–339 markedly inhibited the expansion of OTII Teff, but did not inhibit the expansion of co-transferred SMARTA Teff (specific for LCMV NP61–76) even though the transferred DCs displayed both peptides. Analysis of iTreg-DC co-cultures in vitro using flow cytometry and confocal microscopy demonstrated that specific peptide-MHCII complexes were captured and internalized by iTregs leaving DCs with decreased levels of antigen. Polyclonal iTregs, naïve, and activated antigen-specific Teff did not capture peptide-MHCII complexes. Intravital microscopy of the popliteal lymph node showed that adoptively transferred OTII iTregs made larger clusters around the DC for a longer period of time compared to activated Teff and increased the speed of co-transferred naïve OTII Teff cells. Taken together these studies suggest that antigen-specific iTregs inhibit immune responses locally in an antigen-dependent fashion by forming firm interactions with DCs leading to a stripping of peptide-MHCII complexes from the DC surface by a transendocytosis-based mechanism.
The role of PML in the activation and the differentiation of T cells and B cells
Authors: Lai Peng-Yeh , Lo Yu-Hsun , Lai Ming-Zong 
Published: January 2023

Abstract
Promyelocytic leukemia protein (PML) is a tumor suppressor with diverse activities in cell growth, cell death, stress responses or senescence. PML is a member of the tripartite motif (TRIM) family protein, which contains RING, B-box and coiled-coil domains. Recent studies showed that large number of TRIM family proteins positively regulate innate immune signaling pathways by acting as E3 ubiquitin ligases. To investigate the role of PML in adaptive immunity, we examined the population of different T cell and B cell subsets in PML-knockout mice. The T cells population including CD4+, CD8+, CD25+, effector T, naïve T, and memory T cells were comparable between WT and PML-deficient mice. The B cells population including follicular B, transitional type 1 and 2 B cells, and marginal zone B cells were also comparable between WT and PML-knockout mice. We also determined whether the activation of T cells and B cells were affected by PML-deficiency. It was found that the activation of PML-deficient T and B cells was lower than that of WT cells. We further determined the differentiation of induced regulatory T (iTreg) cells, and observed that iTreg differentiation was comparable in WT and PML-deficient cells. Therefore, PML is not apparently involved in the development of T cells and B cells, and is modesty required for the full activation of T lymphocyte and B lymphocytes. The exact contribution of PML to the activation of T cell and B cell awaits further investigation.
NLRP6 function in inflammatory monocytes reduces susceptibility to colitis in mice
Authors: Chen Grace Yi , Golovchenko Natasha , Schaf Bryan , Chen Jiachen , Eaton Kathryn , Seregin Sergey 
Published: January 2023

Abstract
NLRP6 is a member of the Nod-like receptor (NLR) family, whose members are involved in the recognition of microbes and/or tissue injury. NLRP6 was previously shown to regulate IL-18 secretion and is important for protecting mice against chemically-induced colitis and colitis-associated colon cancer. However, the cellular mechanisms by which NLRP6 reduces susceptibility to colonic inflammation remain unclear. Here, we determined that NLRP6 expression is specifically upregulated in Ly6Chi inflammatory monocytes that infiltrate into the colon during dextran sulfate sodium (DSS)-induced inflammation. Adoptive transfer of WT Ly6Chi inflammatory monocytes into Nlrp6−/− mice was sufficient to protect them from mortality, significantly reducing intestinal permeability and damage. NLRP6-deficient inflammatory monocytes were specifically defective in TNFα production, which was important for reducing DSS-induced mortality and dependent on autocrine IL-18 signaling by inflammatory monocytes. Our data reveal a previously unappreciated role for NLRP6 in inflammatory monocytes, which are recruited during colitis to promote barrier function and limit bacteria-driven inflammation. This study also highlights the importance of early cytokine responses, particularly NLRP6-dependent and IL-18-dependent TNFα production, in preventing chronic dysregulated inflammation that occurs in patients with inflammatory bowel disease.
Identification of two MCMV immunoevasins that modulate NK cell recognition via the NKR-P1B:Clr-b axis
Authors: Aguilar Oscar A , Rahim Mir Munir , Reichel Johanna , Lau Timothy , Samaniego Jackeline , Sampaio Isabella , Krmpotić Astrid , Jonjić Stipan , Makrigiannis Andrew , Allan David S.J. , Carlyle James R 
Published: January 2023

Abstract
Natural killer (NK) cells are a subset of innate lymphoid cells (ILC) capable of recognizing pathological target cells through germline-encoded receptor-ligand interactions. Murine cytomegalovirus (MCMV) is a betaherpesvirus that has co-evolved with its natural host, and as such, a significant portion of its genome encodes immunoevasins that directly target NK cell receptor-ligand interactions. Here, we identify two putative immunoevasins that modulate host-pathogen interactions via the inhibitory NKR-P1B:Clr-b recognition system. First, we identify an m145 family member, m153, that actively prevents MCMV infection-mediated Clr-b downregulation. Ectopic expression of m153 in mouse fibroblasts increases Clr-b expression at the cell surface. In contrast, infection with a virus deficient in m153 shows more substantial Clr-b loss at the cell surface compared to wild-type MCMV. Importantly, enhanced Clr-b loss upon infection with the m153-mutant could be reversed upon m153 complementation by overexpression. Secondly, we have identified an m02 family member, m12, that directly interacts with the NKR-P1B inhibitory receptor in reporter cell assays. Notably, the interaction between NKR-P1B and m12 is both Clr-b/β2m-independent, and infection of fibroblasts with m12-mutant MCMV abrogates NKR-P1B ligation on reporter cells. This interaction, suggestive of decoy ligand function, is also both MCMV strain-dependent and host NKR-P1B allele-specific, suggesting that polymorphisms have evolved at both the pathogen and host levels that affect NK cell recognition of infected target cells.
Murine hemophagocytic lymphohistiocytosis can occur in the absence of interferon-gamma.
Authors: Burn Thomas Niels , Rood Julia Elizabeth , Weaver Lehn , Kreiger Portia A , Behrens Edward M 
Published: January 2023

Abstract
Hemophagocytic lymphohistiocytosis (HLH) is an ultimately fatal disease manifesting as a result of a dysregulated systemic hyperinflammatory response. Infection of perforin knockout (PKO) mice with an acute strain of lymphocytic choriomeningitis virus (LCMV) mimics the human disease. Based on this murine model, the current dogma suggests that disease is driven by excessive production of interferon gamma (IFNγ) by hyper-proliferative, LCMV specific CD8+ T cells. Evidence in humans has however suggested that HLH can develop in the absence of IFNγ signaling. To test this possibility we developed a double knock-out (DKO) mouse lacking both perforin and IFNγ, and show that DKO mice develop multiple HLH disease characteristics to a similar extent to the PKO mice, including weight loss, elevated sCD25, cytopenia, and hepatitis. DKO mice had equivalent numbers of LCMV specific CD8+ T cells in the spleen, and increased numbers of CD8+ T cells displaying a terminal effector phenotype (p&lt;0.05). Interestingly, DKO mice had extensive neutrophilia in the blood, liver, and spleen compared to PKO mice, correlating with elevated serum IL-6 (p&lt;0.01) and IL-1β (p&lt;0.05). We hypothesized that DKO CD8+ T cells drove HLH through an aberrant, type-17 skewing. Indeed, following ex vivo re-stimulation, there was a significant population of IL-17a producing CD8+ T cells, corroborated by an increase in IL-17a and IL-17f transcript levels in purified DKO CD8+ T cells. Overall, these data suggest that perforin deficient HLH can occur independently of IFNγ, which is important to consider as IFNγ blocking therapies begin clinical trials. Additionally we have potentially unveiled an important regulatory mechanism for IFNγ in the control of CD8+ T cell fate decisions.
miR-146a restricts germinal center B cell responses through targeting CD40 signaling pathway
Authors: Cho Sunglim , Lee Hyang-Mi , Choi Youn Soo , Lin Ling-Li , Kang Seung Goo , Xiao Changchun , Crotty Shane , Lu Li-Fan 
Published: January 2023

Abstract
The germinal center (GC) reaction is the hallmark of B cell-mediated immune responses to T cell-dependent (TD) antigens. Engagement of CD40 by its ligand, CD154, which is expressed on activated CD4+ T cells, follicular helper T (Tfh) cells in particular, is crucial for TD humoral immunity. Previously, it has been demonstrated that miR-146a serves as a molecular break in limiting Tfh cells and the resultant GC B cell responses. Here, by taking the mixed bone marrow chimeras as well as the cell-type-specific miR-146a deletion approaches, we show that like Tfh cells, elevated levels of miR-146a in B cells are equally important in controlling humoral immunity as miR-146a deficiency leads to increased GC B cell differentiation. Moreover, deletion of miR-146a specifically in isotype-switched B cells also resulted in augmented GC responses, suggesting that continued miR-146a expression in GC B cells is required for the maintenance of optimal GC reactions. Mechanistically, we found that miR-146a-ablated B cells exhibit elevated CD40 expression and that enhanced CD40 signaling is accounted for the dysregulated GC responses in mice with B cell-specific miR-146a ablation. Together, our study demonstrates an indispensable role of miR-146a in restricting GC B cell responses and suggests that miR-146a is a critical negative regulator in controlling both T and B cells, two key arms in orchestrating protective humoral immunity.
ROLE OF LIPID RAFT-BASED MEMBRANE ORDER IN SIGNALING THROUGH THE ANTIGEN RECEPTOR IN CD4+ T CELLS: INVESTIGATING THE MECHANISM
Authors: Bamezai Anil K , Bakun Walter 
Published: January 2023

Abstract
Plasma membrane of all animal cells are highly organized into liquid ordered (Io) and liquid disordered (Id) phases. While Io phase is enriched in saturated lipids, cholesterol and lapidated proteins, the unsaturated lipids and some proteins are the major constituents of the Id phase. Lipid rafts nano-domains on the membrane that are enriched in cholesterol and saturated lipids, constitute, in-part, the ordered phase of the membrane. We have previously reported the role of membrane order in spatiotemporal signaling in primary CD4+ T lymphocytes expressing αβ T cell receptor with specificity to chicken ovalbumin323–339 peptide (cOva323-339) (Schieffer et. al., 2014, BMC Immunology 15:58). Primary DO11 CD4+ T cells with disrupted lipid raft-based membrane order lose their proliferative capacity to clonally expand in response to cOva323-339. Moreover, integrity of membrane order within 120 minutes of antigen exposure is critical for antigen-specific clonal expansion of CD4+ T cells. Since early events of T cell activation are initiated at the plasma membrane we examined the effect of membrane disorder on key signaling proteins participating in early CD4+ T cell signaling, such as, p56lck, Zap70, LAT, PLC-γ1, and Akt. We show that disruption of lipid raft-based membrane order does not inhibit the early phosphorylation events associated with aforementioned signaling proteins after engaging the TCRαβ/CD3 complex on primary CD4+ T cells. We are currently assessing the contribution of accessory molecules/adhesion proteins expressed on CD4+ T cells whose biological function may depend on integrity of lipid raft-based membrane order.
PD-1 inhibits the TCR signaling cascade by sequestering SHP-2 phosphatase, preventing its translocation to lipid rafts and facilitating Csk-mediated inhibitory phosphorylation of Lck.
Authors: Bardhan Kankana , Patsoukis Nikolaos , Weaver Jessica , Freeman Gordon , Li Lequn , Boussiotis Vassiliki A 
Published: January 2023

Abstract
PD-1 inhibits T cell responses but the biochemical mechanisms are poorly understood. PD-1 cytoplasmic tail contains an ITIM and an ITSM motif. SHP-2 tyrosine phosphatase interacts with the ITSM and has a critical role in PD-1-mediated inhibition. Although phosphatases are considered negative regulators of activation, SHP-2 deficient T cells display impaired activation of MAPK in response to TCR/CD3 stimulation. Conversely, SHP-2 mutations leading to gain of function induce activation of Ras-MAPK pathway in AML. Thus, SHP-2 may activate some signaling pathways. We investigated how PD-1: SHP-2 interaction inhibits T cell activation. A key event required for activation of the TCR/CD3 signaling cascade is the downregulation of Csk-mediated inactivating phosphorylation of Lck on Tyr-505. Growth factor stimulation of epithelial cells recruits SHP-2 to the plasma membrane and abrogates Csk-mediated inactivating phosphorylation of Src kinase. We determined that TCR/CD3 stimulation downregulated Lck phosphorylation on Tyr-505 but this was prevented by PD-1 ligation. Because Lck is localized in membrane lipid rafts, we examined whether SHP-2 might be recruited to the rafts. TCR/CD3 stimulation resulted in translocation of SHP-2 to the lipid rafts. In contrast, PD-1 ligation recruited SHP-2 to the PD-1 ITSM abrogating translocation of SHP-2 to the rafts and resulted in enhanced Lck phosphorylation on Tyr-505. Our results unravel a previously unidentified mechanism via which PD-1 inhibits T cell activation by sequestering SHP-2 and preventing its translocation to the site on the plasma membrane where SHP-2 plays a key role in activating the TCR signaling cascade by reversing Csk-mediated inactivating phosphorylation of Lck.
A calcium-dependent PKC, independent of NF-κB, is required for proper initiation of chromatin decondensation during T-cell activation.
Authors: Rawlings Jason S , Swatzel Hayley , Ward Audrey , Eikenbusch Sarah , Shields Molly , Meredith Jenna , Mitchell Taylor , Bingham Kellie , Lee Megan 
Published: January 2023

Abstract
Following antigen engagement at the T-cell receptor (TCR), there are two known signaling pathways that are involved in the activation of T-cells, initiated by DAG and IP3. These signaling pathways ultimately lead to chromatin decondensation, which is required for subsequent T-cell proliferation mediated by IL-2. It has previously been demonstrated that intracellular calcium is necessary for proper chromatin decondensation but that calcium does not act through transcription factor NFAT. In this study, we demonstrate that PKC, activated through DAG, is also required for proper chromatin decondensation. Furthermore, we show that calcium is required for PKC mediated chromatin decondensation, suggesting that a calcium dependent isoform of PKC is involved in the process. Interestingly, PKC but not IP3 is required for subsequent competence of T-cells to respond to IL-2 signaling. Finally, we show that PKC does not act downstream through NF-κB to decondense chromatin and our data suggest that NF-κB is not required for IL-2 competence. Collectively, these data could be suggestive of multiple mechanisms to control the activation and proliferation of T-cells during an immune response.