bluuebunny/crossref_metadata_2025_split huggingface dataset:
ADAM protease-mediated cleavage of Delta-like-1 regulates the degree of Notch signaling during T cell development (85.18)
Authors: Gravano David M , Manilay Jennifer O 
Published: January 2023

Abstract
Hematopoietic progenitor cells require Notch signaling in the thymus to develop into mature T cells. Members of the Delta-like family of Notch ligands expressed on thymic epithelial cells (TECs) initiate this signaling. Delta-like-1 (Dll1) is proteolytically processed by ADAM (a disintegrin and metalloprotease) proteases, but the effect of this cleavage on T cell development has not yet been analyzed. Mice lacking ADAM17 in TECs display blocks in T cell development (Li, N. et al. J Immunol 2007. 178(7) p. 4214-21), leading to speculation that Notch signaling between TECs and thymocytes is aberrant in these animals. The objective of our study is to determine the functional significance of proteolytic cleavage of the Delta-like ligands on T cell development. Using the well-established OP9-Dll1 in vitro T cell differentiation system, we observed that Dll1 cleavage on OP9 cells does occur in the presence of thymocyte progenitors. A non-cleavable Delta-like-1 construct (NC-Dll1) (Six, E. et al. Proc Natl Acad Sci USA 2003. 100(13) p. 7638-43) was utilized to elucidate the functionality of Dll1 cleavage on thymocyte differentiation. Lack of Dll1 cleavage did not affect T lineage fate or development. However, Notch signaling was potentiated in hematopoietic progenitor cells cultured on OP9-NC-Dll1, as measured by higher expression of the Notch target gene Hes1. These data indicate that proteolytic cleavage of Dll1 may function to reduce the level of Notch signaling in developing thymocytes. In conclusion, ADAM mediated cleavage of Dll1 occurs during the process of T cell development, but blocking it does not appear to stunt development toward the T cell lineage and rather, increases the strength of Notch signaling.
Real time multi-photon imaging reveals coordination between thymocyte development, location and migration through intrathymic microenvironments (85.6)
Authors: Ehrlich Lauren I Richie , Oh David Y , Lewis Richard S , Weissman Irving L 
Published: January 2023

Abstract
As they develop, CD4-CD8- (DN) thymocytes are found progressively from the corticomedullary junction towards the capsule. Following beta selection, CD4 and CD8 are expressed, generating double positive (DP) thymocytes that are found throughout the cortex. If a DP thymoycte expresses T cell receptor (TCR) and passes positive-selection, it becomes a single positive (SP) thymocyte, which is located in the medulla. Static images have revealed this intrathymic localization, suggesting a model in which DN thymocytes migrate directionally towards the capsule, while DP thymocytes move towards the medulla, which they enter as SP thymocytes.
Using multi-photon imaging of thymocyte subsets in thick thymic slices, we directly test this model. Using thymuses expressing EGFP, we identify the precise microenvironments in which thymocyte subsets are localized. For the first time, we now image within the thymic medulla. We find that DN and DP thymocytes migrate without directional bias throughout the cortex, but DP velocities are influenced by cortical micorenvironmental cues. Interestingly, only SP thymocytes enter the medulla, where they migrate very rapidly. SPs also migrate rapidly in the cortex, where their movement is biased towards the medulla. Importantly, medullary entry is strictly dependent on G-protein-coupled receptor activity, though CCR7 signaling cannot entirely account for this requirement.
L.I.R.E is a Leukemia and Lymphoma Society Special Fellow
Age-dependent T and B lymphocyte subsets defined by multicolor flow cytometry (86.13)
Authors: Crabtree Matthew Jude , DeRosa Stephen C. , Cohen Gordon , Wiedeman Alice , Stevens Anne M 
Published: January 2023

Abstract
Immune dysregulation in children due to primary immunodeficiency, autoimmune disease or immunomosuppressive therapy may be characterized in detail by multiparametric flow cytometry. To determine age-dependent reference values for healthy children, we developed four panels: aß and γδ T lymphocytes; regulatory T lymphocytes; B lymphocytes; NK and NK T cells. Detailed analyses performed on 18 healthy subjects aged 8 to 46 years revealed differences between adult and juvenile phenotypes in 66 of 301 distinct subsets. Among naïve aß T lymphocytes (CD45RA+CCR7+CD27+) we found a 60% decrease in the CD4+ subset but no change in the CD8+ subset in adults compared to children. Expression of CD31, an aß T lymphocyte marker of recent thymic emigration, decreased 50% with age. T regulatory cells (CD4+CD127loCD25+FoxP3+) were 30% lower in adults. No differences were found in major γδ T lymphocyte, NK, or NK T cell subsets. Memory B cells (CD38loCD24+) increased 2-fold with age, while naïve B cells (CD24hiCD38+IgM+IgD-) decreased by 50%. Thus, the influence of aging greatly effects subset frequencies, and may reflect decreasing thymus function and acute/chronic stimulation of memory B and T lymphocytes. Phenotypic analysis of leukocyte subsets may serve as a valuable tool for detecting and monitoring immune dysregulation in children, but age-matched controls are essential.
Supported by the McMillen Foundation
Functional competence of T cells and resistance to thymic involution in long-lived mice deficient in pregnancy-associated plasma protein A (PAPPA) (86.2)
Authors: Vallejo Abbe N , Michel Joshua J , Bale Laurie K , Lemster Bonnie H , Borghesi Lisa A , Conover Cheryl A 
Published: January 2023

Abstract
Thymus organogenesis is dependent on insulin-like growth factor (IGF), but involuted thymi of old mice cannot be reconstituted with infusion of IGF. In adult humans, tumor growth is associated with local upregulation of IGF, but increased incidence of cancer with aging is associated with decreasing levels of serum IGF. We hypothesized that suppression of tissue availability of IGF prevents/delays thymic atrophy and maintains a pool of functionally competent T cells throughout life. Hence, we examined mice with homozygous deletion of PAPPA, a gene encoding for a protease that degrades inhibitory IGF-binding proteins (IGFBP) that limit IGF levels in tissues. PAPPA-/- mice have normal serum IGF levels, indicating maintenance of the endocrine IGF reservoir. They have 40% extension of lifespan; and have reduced burden of spontaneous tumors, the major cause of early mortality of wildtype mice. Strikingly, PAPPA-/- mice aged =18 months have histologically organized thymi densely populated by CD4+CD8+ thymocytes with high TREC levels. Bone marrows of old mutants are enriched with thymus-seeding progenitors. Old mutant mice have a diverse repertoire of T cells that are functionally indistinguishable from young wildtype mice. These data indicate an IGF-immune axis of longevity. We suggest that PAPPA-mediated proteolysis is a potential target for intervention to maintain thymic function and promote healthy aging.
Human thymic epithelial cell (TEC) culture system for promoting T lineage commitment and development of T cells from cord blood and bone marrow stem cells (86.6)
Authors: Le Phong T , Zhang Shubin , Beaudette-Zlatanova Britte , Stiff Patrick J , Knight Katherine L 
Published: January 2023

Abstract
The discovery of Delta-like-1 (Dl1)/Notch signaling as the earliest requirement for T lineage commitment and development makes it possible to generate T cells from hematopoietic stem cells in vitro. The mouse bone marrow stroma OP9 cells that overexpress Dl1is the first stroma cell line that is capable of promoting the development of both mouse and human T cells; however, a similar approach with human stroma cells has not been established. To develop a similar culture system to closely emulate human T cell development, we have generated a human TEC line from a pediatric thymus and expressed the mouse Dl1 in this line (TEC84-Dl1). The TEC84-Dl1 expresses CD104, CD29, CD49f, CD54 (ICAM-1), and CD106 (VCAM-1); these cells also express HLA-ABC and HLA-DR. When TEC84-Dl1 were co-cultured with cord blood CD34posCD45RAposCD38neg cells, we were able to generate preT/NK (CD34posCD7posCD1aneg), preT (CD34posCD7posCD1apos), immature single positive and double positive subsets; the co-culture system also generated a CD3pos subset. Similar results were also obtained with CD34pos cells isolated from adult bone marrow. Thus, our co-culture system with the human TEC provides a complete human system for replicating thymopoiesis in vitro and offers a novel tool to optimize the development of T lineage cells that would benefit cord blood and bone marrow transplant recipients (Supports: AG023809 to PL, IDPH to PS, AI068390 to KK).
Potential role for serum soluble CD200 in human Chronic Lymphocytic Leukemia (88.15)
Authors: Wong Karrie K , Shaha Suchinta , Spaner David , Gorczynski Reg 
Published: January 2023

Abstract
CD200, a transmembrane protein expressed on multiple cell types, regulates anti-tumor immunity in animal models. Its overexpression is associated with a poor prognosis in human AML, MM, and melanoma. Blockade of CD200 expression on CD200-expressing tumor cells using CD200-specific monoclonal antibodies or siRNA enhanced anti-tumor immunity against tumor cells both in vitro and in vivo. A soluble variant of CD200 (sCD200) is detectable in human serum, and patients with Chronic lymphocytic leukemia show elevated serum levels.
We investigated the correlation between serum sCD200 levels and clinical disease in CLL patients. sCD200 levels are associated with Rai disease stage and lymphocyte-doubling time. Shedding of cell surface CD200 from CLL cells in vitro can be induced by PMA and TLR7 agonists, with patient-to-patient variability. Shedding of CD200 is correlated with patient serum sCD200 levels, suggesting that inherent differences of CLL cells in responses to shedding stimuli may have clinical significance.
sCD200 levels in serum may provide prognostic and/or diagnostic information in CLL, and may contribute to the efficacy of treatments targeting cell-surface CD200.
Identification of IL-17-producing FOXP3+ regulatory T cells in humans (89.1)
Authors: voo kui S , Wang Yui-Hsi , Santori Fabio R , Boggiano Cesar , Wang Yi-Hong , Arima Kazuhik , Bover Laura , Hanabuchi Shino , Khalili Jahan , Marinova Kkaterina , Zheng Biao Q , Littman Dan R , Liu Yong-Jun 
Published: January 2023

Abstract
IL-17-producing CD4+ T cells (Th17) have recently been defined as a unique subset of pro-inflammatory helper cells whose development depends on signaling initiated by IL-6 and TGF-β, autocrine activity of IL-21, activation of STAT3, and induction of the orphan nuclear receptor RORγt. The maintenance, expansion and further differentiation of the committed Th17 cells depends on IL-1β and IL-23. IL-17 was originally found produced by human CD45RO+ memory T cells. We report that human peripheral blood and lymphoid tissue contain a significant number of CD4+FOXP3+ T cells that express CCR6 and produce IL-17 upon activation. These cells co-express FOXP3 and RORγt transcription factors and strongly inhibit the proliferation of CD4+ responder T cells. CD4+CD25high-derived T cell clones express FOXP3, RORγt and IL-17, and maintain their suppressive function. We further show that human CD4+FOXP3+CCR6- Treg cells differentiate into IL-17 producer cells upon TCR stimulation in the presence of IL-1β, IL-2, IL-21, IL-23 and human serum. This, together with the finding that human thymus does not contain IL-17-producing Treg cells, suggests that the IL-17+FOXP3+ Treg cells are generated in the periphery. IL-17-producing Treg cells may play critical roles in anti-microbial defense while controlling autoimmunity and inflammation.
This work was supported by KECK Foundation 01, PP-4 and National Institute of Health Grant AI091130 (to Y.-J.L.)
Antigen-specific suppression of non-lymphoid tissue auto-antibody production by CD25+ FoxP3+ regulatory T cells (89.22)
Authors: Kurts Christian , Ludwig-Portugall Isis , Hamilton-Williams Emma E , Gottschalk Catherine , Gotot Janine 
Published: January 2023

Abstract
To study how peripheral B cell tolerance against non-lymphoid tissue autoantigens is maintained, we generated transgenic RIP-OVA/HEL (ROH) mice expressing the model antigens, OVA and HEL, in pancreatic islet beta cells. Immunization with OVA/HEL/aluminiumhydroxide induced IgG auto-Ab titers that were much lower than in non-transgenic controls. Depletion of CD25+ cells during immunization completely restored auto-Ab production but did not affect titers against foreign antigens, indicating regulatory tolerance. Purified CD25+ FoxP3+ CD4+ T cells from ROH mice transferred B cell suppression into non-transgenic recipients. CD25+ cells also suppressed naïve transgenic HEL-specific B cells adoptively transferred into ROH mice, confirming peripheral B cell tolerance. B cell suppression mechanistically involved inhibiting the proliferation of autoreactive B cells, inducing their apoptosis after immunization with autoantigen, suppressing antibody secretion per B cell and downregulating IgMa and MHC II B cell surface expression in the autoantigen-draining lymph node. We conclude that CD25+ FoxP3+ regulatory T cells were necessary and sufficient to specifically suppress auto-Ab production against pancreatic islet cell antigens.
Suppression of the Immune Responses to Factor VIII in the Hemophilia A Mice by Delivery of Transgene Modified Apoptotic Syngeneic Fibroblasts (89.36)
Authors: Su Rui-Jun , Epp Angela , Latchman Yvette , Josephson Neil 
Published: January 2023

Abstract
The development of anti-FVIII inhibitory antibodies is a major obstacle to treatment of hemophilia A patients. Here, we employ the immunosuppressive properties of FVIII gene modified apoptotic syngeneic fibroblasts to reduce immune response to FVIII in hemophilic mice. We generated a fibroblast cell line from the 129Sv-FVIII KO mouse that expresses both FVIII and zeocin resistance gene. A cell line expressing only the zeocin resistance gene was also generated. Both vector modified cell lines were maintained under selective pressure and induced to apoptose just prior to infusion into 129Sv-FVIII KO mice. Mice treated with 2 intravenous infusions of FVIII expressing apoptotic fibroblasts showed up to a 79.5% reduction in Bethesda titers and significantly lower T cell responses after subsequent challenge with 4 doses of rhFVIII. Moreover, hemophilic mice pre-immunized with rhFVIII showed a 65% reduction in Bethesda titers following treatment with 4 infusions of FVIII expressing apoptotic cells. To investigate the antigen specificity of the induced immunosuppression, apoptotic fibroblast treated mice were challenged with an unrelated protein OVA. The immune response to OVA was not affected by the infusion of apoptotic cells. In adoptive transfer studies, a blunted immune response to rhFVIII could be induced in naïve mice by infusion of CD4+ splenocytes from FVIII expressing apoptotic cell treated animals. Moreover, in vitro Treg suppression assays showed that CD4+CD25+ regulatory T cells from FVIII expressing apoptotic cell treated mice were capable of inhibiting the T cell response to rhFVIII, but not to OVA. These data demonstrate that the CD4+CD25+ regulatory T cells in these mice direct antigen specific immune suppression to human FVIII.
Costimulation through ICAM-1 induces the differentiation of human naïve CD4+ T cells to regulatory T cells: acquisition of distinct signaling and homing profiles during differentiation (89.39)
Authors: Cool Kelli M. , Dotson Abby L. , Benedict Stephen H. 
Published: January 2023

Abstract
Inducible regulatory T (Treg) cells are important mediators of peripheral tolerance that arise by mechanisms not fully defined. We have previously shown that a subset of human naïve CD4+ T cells that are costimulated through Intercellular Adhesion Molecule-1 (ICAM-1) will differentiate into cells with a Foxp3+CD25+CD127(-) phenotype and suppressive function characteristic of inducible Treg cells. Our present work identifies some of the signaling pathways that are activated during this differentiation process. We also characterize some of the chemokine receptors and other homing markers that are displayed on these Treg cells, including CCR7, CD62L, and specific integrins. These results help clarify the signaling requirements for in vitro differentiation of human naïve CD4+ T cells to Treg cells after costimulation through ICAM-1 and suggest possible microenvironments in which these cells could migrate and function during immune responses in vivo.
This work was supported by the National Institute on Aging/NIH.
Bone marrow-derived dendritic cells generated in the presence of resolvin E1 induce apoptosis of activated CD4+T cells (90.1)
Authors: Vassiliou Evros K , Tadros James H , Kessler Olga M , Ganea Doina 
Published: January 2023

Abstract
In contrast to the role of dendritic cells (DC) in immunity and tolerance, little is known about their possible role in the resolution of inflammatory processes. Elimination of effector T cells present at the inflammatory site represents an essential step toward resolution. Recently, lipid mediators such as the omega-3 fatty acids and their metabolites, including resolvin E1 (RvE1), have been shown to accumulate in inflammatory foci during the resolution phase. RvE1 has been reported to reduce immune cell infiltration and proinflammatory cytokine production. In this study we report that DC exposed to RvE1, especially during differentiation, induce apoptosis of activated T cells through expression of indoleamine 2,3-dioxygenase (IDO). To our knowledge, this study is the first to report on an omega-3 fatty acid derivative inducing IDO expression in DC. RvE1-DC maintain an immature chemokine receptor expression pattern even following TLR stimulation, with high CCR5 and no CCR7 expression. This effect implies that DC exposed to RvE1 and pathogens remain at the inflammatory site where they induce apoptosis in infiltrating effector T cells. To our knowledge, the DC described in this study represent a new functional DC subtype, whose essential function resides in the resolution of inflammation.
Support: 2R01AI052306 (D.G.) and a grant from the Office of Research and Sponsored Programs of Kean University (E.K.V.).
DAP12 signaling in osteoclasts and macrophages is regulated by SHIP1 and PI3K binding to the ITAM of DAP12 (91.2)
Authors: Peng Qisheng , Humphrey Mary Beth 
Published: January 2023

Abstract
TREM2-DAP12 is critical for regulating TLR signals in macrophages and for normal osteoclastogenesis (OC). Negative regulation of DAP12 in OC and macrophages has not been reported and is the goal of this study. Our studies reveal that Src homology region 2(SH2)-containing inositol phosphatase (SHIP1) negative regulates DAP12 signaling. TREM2 antibody (Ab) cross-linking of mouse bone marrow macrophages (BMM) leads to association of SHIP1 with DAP12, not seen with control Ab. The SH2- domain of SHIP1 interacts with DAP12 in a phospho-tyrosine specific manner within the immunoreceptor tyrosine-based activation motif (ITAM). Signaling induced Pho-Akt, Erk1/2, VAV3 and Syk activation, and these signals were enhanced in SHIP1-/- BMM compared to wild type (WT) BMM. Cross-linking with anti-TREM2 monoclonal Ab, but not control Ab, lead to a 4 fold increase in OC generated from SHIP1-/- BMM compared to WT BMM. Analysis of the molecular mechanism reveals that SHIP1 regulates PI3K regulatory subunit P85a binding to the ITAM of DAP12. SHIP1-/- BMM displayed enhanced P85a binding to DAP12 in response to TREM2 cross-linking. Abrogation of PI3K activity leads to increased association of SHIP1 with DAP12. In OC and BMM, DAP12, SHIP1 and actin co-localize, and TREM2 stimulation leads to actin cytoskeletal changes. Together, these data reveal SHIP1 interacts with DAP12 and negatively regulates DAP12 through inhibition of PI3K binding to DAP12.
Differential PPAR γ and δ expression in F4/80hi and F4/80lo adipose tissue macrophages (92.8)
Authors: Bassaganya-Riera Josep , Guri Amir J , Hontecillas Raquel 
Published: January 2023

Abstract
Chronic inflammation and macrophage infiltration into adipose tissue are hallmarks of obesity. The objective of this study was to phenotypically and functionally characterize the subsets of adipose tissue macrophages (ATM). We had previously identified two distinct subsets of ATM based on surface expression of the glycoprotein F4/80. Changes in gene expression were examined on sorted F4/80lo and F4/80hi ATM by quantitative real-time RT-PCR and their phenotype assess by flow cytometry. While F4/80lo macrophages predominate in adipose tissue of lean mice, obesity resulted in increased accumulation of both F4/80lo and F4/80hi ATM. The F4/80hi population consistently expressed greater amounts of CD11c, MHC II, CD49b, and CX3CR1 on its cell surface and produced more TNF-α, MCP-1, and IL-10 than the F4/80lo subset, which contained a distinct Ly6ChiCCR2hi population. Gene expression analyses of the sorted populations showed that only the F4/80lo population produced IL-4, whereas the F4/80hi ATM expressed greater amounts of peroxisome proliferator-activated receptor (PPAR) γ, δ, CD36,TNF-α and toll-like receptor-4. Therefore, both the F4/80lo and F4/80hi ATMs are heterogeneous populations, with the F4/80hi population consisting of classically activated and deactivated macrophages expressing PPAR γ and δ and the F4/80lo population consisting mainly of IL-4-expressing alternatively activated M2 macrophages.
Lupus serum induces skin inflammation through TNFR1 pathway (93.1)
Authors: Deng Guo-Min , Liu Lena , Kyttaris Vasileios C , Tsokos George C 
Published: January 2023

Abstract
Systemic lupus erythematosus (SLE) is an autoimmune disease characterized by high levels of autoantibody and multi-organ tissue damage including kidney and skin. Skin manifestations are frequent in patients with SLE and because of limited understanding of the involved pathogenic mechanisms there is no specific treatment. Skin injury is also frequent in the lupus-prone MRL/lpr mice. We investigated whether lupus serum containing high levels of immunoglobulin can cause skin injury. We found that serum from patients and mice with lupus induced skin inflammation following intradermal injection in normal mice. Immunohistochemistry demonstrated that tumor necrosis factor receptor (TNFR) 1 but not TNFR2 was expressed in the skin lesions caused by injected lupus serum. The expression of NF-kB, iNOS and MCP-1 were also markedly increased in the induced skin lesions. The severity and incidence of lupus serum-induced skin inflammation were significantly decreased in TNF-alpha-deficient mice. Skin inflammation induced by lupus serum was abrogated in TNFR1-deficient mice. In contrast TNFR2 or IL-1R-deficient mice developed skin lesions comparable to those observed in normal mice injected with the same lupus sera. Our studies demonstrate that lupus serum causes skin injury and TNFR1 exerts a crucial role in the pathogenesis of lupus serum-induced skin injury by engaging TNFR1 but not TNFR2 or IL-1R. Therefore, disruption of TNFR1-mediated signaling process may be of therapeutic value in patients suffering of skin in SLE.