bluuebunny/crossref_metadata_2025_split huggingface dataset:
Immunoproteasome activity controls the balance of inflammatory and regulatory gene expression in T helper cells (152.21)
Authors: Suzuki Erika , Muchamuel Tony , Arastu-Kapur Shirin , Kirk Christopher 
Published: January 2023

Abstract
The immunoproteasome (iPr), a unique form of the proteasome found in cells of the immune system, regulates cytokine production and differentiation of Th1 and Th17 cells in vitro in an NF-kB independent manner. However, the role of the iPr in other T-cell subsets and the specific molecular signaling events regulated by the iPr are not well understood. We found that FoxP3 and TGF-β expression increased in Treg cells exposed to a selective iPr inhibitor (ONX 0914, formerly PR-957) but that IL-4 production in Th2 cells was unaffected by iPr inhibition. Interestingly, increased FoxP3 expression was noted in Th0 and Th1 cells exposed to ONX 0914. Inhibition of the iPr resulted in reduced phosphorylation of STAT1 and STAT3 in Th1 and Th17 cells, respectively. Decreased basal and IL-6 stimulated STAT3 phosphorylation was noted immediately following iPr inhibition suggesting a receptor proximal event but at later timepoints coincided with reduced gene expression. After a brief exposure to ONX 0914, Th17 and Treg cells show a similar pattern of protein accumulation as measured by 2D Diffference Gel Electrophoresis and included the regulatory subunit of PP2A, a protein phosphatase known to regulate STAT3 and other transcription factors. Collectively, these results suggest that the iPr regulates Th cell plasticity via PP2A activity.
Altered T cell differentiation mediated by heterozygous SOCS1 expression: implications for autoimmunity (152.23)
Authors: Wilson Tenisha , Larkin III Joseph 
Published: January 2023

Abstract
Suppressor of cytokine signaling-1 (SOCS1) is an intracellular protein that negatively regulates cytokine signaling. Heterozygous expression of SOCS1 leads to T lymphocyte mediated autoimmunity, suggesting that reduced expression of SOCS1 can disrupt immune system tolerance through aberrant cytokine signaling in lymphocytes. Immune system tolerance to self-tissues is dependent upon proper differentiation of naïve T lymphocytes (Tresp) subsequent to activation. Although it is known that cytokines are essential for Tresp differentiation, it is poorly understood how heterozygous expression of SOCS1 affects this process. We demonstrate that heterozygous expression of SOCS1 does not affect Treg induction from naïve Tresp. However, it does disrupt Th17 differentiation and results in a Th1 bias, as SOCS1 heterozygous Tresp that have been placed in Th17 inducing conditions have decreased IL-17 and increased IFN-gamma message expression. These results suggest that the systemic autoimmunity experienced by SOCS1 heterozygous mice may not be due to decreased Treg induction, but rather a predominant Th1 bias caused by dysregulated IFN-gamma signaling as a result of reduced expression of SOCS1.
TCR-CARMA1-NF-κB controls Th17 differentiation (152.4)
Authors: Molinero Luciana , Alegre Maria-Luisa 
Published: January 2023

Abstract
IL-17 producing-CD4 T cells play a key role in immune responses against extracellular bacteria and autoimmunity. The transcription factor NF-kB is required for T cell activation and effector functions. Here, we investigated the role of T cell receptor (TCR)-mediated NF-kB in Th17 differentiation. In vitro, cells deficient in the adaptor molecule CARMA1, necessary for TCR-NF-kB signaling, did not differentiate towards a Th17 program, as shown by absence of IL-17A or IL-17F, IL-22, IL-21, IL-23R and CCR6. Consistently, CARMA1-deficient mice did not develop Th17-driven experimental autoimmune encephalomyelitis. CARMA1 selectively affected Th17 but not Th1 or Th2 differentiation in a cell intrinsic manner. While CARMA1 controls both NF-kB and JNK2 TCR-mediated activation, only NF-kB-impaired T cells (IkBaDN-Tg) had defective Th17 differentiation, confirming that Th17 differentiation requires intact TCR-CARMA1-NF-κB signaling. Despite impaired Th17 differentiation, CARMA1-deficient cells had intact IL-6 or TGFb signaling, as assessed by p-STAT3 and p-Smad2/3. Moreover, induction of transcription factors essential for Th17 differentiation such as RORgt, proceeded normally in CARMA1-deficient T cells. Notably, accessibility to the IL-17 locus was impaired in CARMA1-deficient cells. Our results demonstrate that TCR-CARMA1-NF-κB controls Th17 differentiation by enabling IL-17 locus accessibility. Targeting T cell NF-kB could be potentially used as therapy for autoimmune diseases.
The differentiation of pathogenic Th17 cells is negatively regulated by the transcription factor ELF4 (152.6)
Authors: Lee Ping-Hsien , Lacorazza H. Daniel 
Published: January 2023

Abstract
T helper 17 (Th17) cells are potent inducers of tissue inflammation involved in several autoimmune diseases such as multiple sclerosis (MS). Although the importance of environmental factors such as IL-6, IL-21, and IL-23 has been well established, the transcriptional network regulating lineage specification and acquisition of effector function in Th17 cells is not entirely understood. We found that loss of the transcription factor ELF4 led to increased in vitro Th17 differentiation without significant alteration in Th1, Th2, and Treg polarization. The increased differentiation of Elf4-null Th17 cells was also observed in the absence of TGFβ signaling, known to abrogate pathogenicity of Th17 cells, suggesting that polarized Elf4-null CD4+ T cells may be more pathogenic. By using experimental allergic encephalomyelitis (EAE), a mouse model for human MS, we found that Elf4-null mice exhibited an earlier onset and increased severity of disease compared to wild-type mice, supporting a negative role of ELF4 in pathogenicity of Th17 cells in vivo. To understand how ELF4 modulates Th17 differentiation, we investigated cytokine signaling in Elf4-null CD4+ T cells. Increased phosphorylation of STAT3 was observed in Elf4-null CD4+ T cells after 5-min and 30-min IL-6 stimulation. Collectively, our study identified a novel intrinsic regulator that may inhibit Th17 differentiation by dampening cytokine signaling through STAT3 inhibition.
Characterization of different subsets of human follicular helper T (TFH) cells (152.9)
Authors: Choi Jinyoung , Kim Sang Taek , Lainez Begona , Craft Joseph 
Published: January 2023

Abstract
Follicular helper T (TFH) cells are specialized CD4+ T cells that are localized in B cell follicles and help B cells produce antigen-specific antibodies via contact and secretion of IL-21 and IL-4. In mice, they are characterized by high expression of CXCR5, PD-1, ICOS, and Bcl-6, and low expression of P-selectin glycoprotein ligand-1 (PSGL-1); however, the study of TFH cells in human is more limited. Here we identified three subsets of human tonsillar TFH cells (CXCR5hiPD-1hiICOShiPSGL-1lo) based upon the expression of CD127 and CD57 and characterized them using flow cytometry, tissue distribution, microarray analysis, and B cell help, and compared them to traditional Th effector subsets and naïve cells. TFH cells, residing in the B cell follicle and germinal center (GC) by confocal microscopy, were CD45RAloCXCR5hiPD-1hiICOShiPSGL-1lo. Following sorting, the three subsets of TFH cells produced comparable levels of IL-21 and IL-4, and expressed transcripts of Bcl6. In addition, these subsets efficiently induced GC B cells to produce switched immunoglobulin. By contrast, Th1 and Th17 cells, as defined by IFNγ and IL-17 secretion and by Tbx21 and Rorc expression, respectively, were CD45RAloCXCR5loPD-1loPSGL-1hi, with T cell zone residence. These studies define characteristics of TFH subsets in human tonsils and potentially pave the way for identifying therapeutic targets in SLE. Work to investigate their unique function and differential gene expression is underway.
Early Growth Response Gene-2 regulates the development of B and T cells (153.15)
Authors: Li Suling , Symonds Alistair L.J. , Zhu Bo , Liu Mengya , Raymond Meera V. , Miao Tizong , Wang Ping 
Published: January 2023

Abstract
Understanding of how transcription factors are involved in lymphocyte development still remains a challenge. It has been showed that Egr-2 deficiency results in impaired NKT cell development and defective positive selection of T cells. Here we investigated the development of T, B and NKT cells in Egr-2 transgenic mice and the roles in the regulation of distinct stages of B and T cell development. The expression of Egr1, 2 and 3 were analysed at different stages of T and B cell development by RT-PCT and results showed that the expression was strictly regulated at different stages. Forced expression of Egr-2 in CD2+ lymphocytes resulted in a severe reduction of CD4+CD8+ (DP) cells in thymus and pro-B cells in bone marrow, which was associated with reduced expression of Notch1 in ISP thymocytes and Pax5 in pro-B cells, suggesting that retraction of Egr-2 at the ISP and pro-B cell stages is important for the activation of lineage differentiation programs. In contrast to reduction of DP and pro-B cells, Egr-2 enhanced the maturation of DP cells into single positive (SP) T and NKT cells in thymus, and immature B cells into mature B cells in bone marrow. Our results demonstrate that Egr-2 expressed in restricted stages of lymphocyte development plays a dynamic, but similar role for the development of T, NKT and B cells
Asynchronous and modular repression of neutrophil production by IRF8 leads to the development of progenitors with partially overlapping lineage potentials. (153.24)
Authors: Bhattacharya Deepta , Becker Amy , Satpathy Ansuman , Murphy Kenneth 
Published: January 2023

Abstract
Most previous studies have assumed that the maturation of a particular blood cell type downstream of hematopoietic stem cells follows a singular developmental route; therefore the identification of distinct hematopoietic progenitors with partially overlapping lineage potentials has led to considerable controversy. For example, common lymphoid progenitors (CLPs) and common myeloid progenitors (CMPs) both generate dendritic cells upon adoptive transfer in vivo. To determine the molecular mechanisms by which progenitors with partially overlapping lineage potentials arise, we examined the transcriptional changes that occur as lymphoid-primed multipotent progenitors (LMPPs) differentiate into CLPs, and as CMPs differentiate into common dendritic cell progenitors (CDPs). In both of these independent pathways, we determined that the expression of the transcription factor IRF8 was strongly induced. IRF8-/- mice showed reduced numbers of both CLPs and CDPs. Competitive bone marrow reconstitutions also demonstrated cell-intrinsic defects in the generation of CD8a- dendritic cells, previously reported to be normal in IRF8-/- mice. Microarray comparisons between dendritic cells derived from either wild type CMPs or CLPs demonstrated that these cells are identical. Thus, the asynchronous expression of IRF8 leads to the formation of progenitors with partially overlapping developmental potentials, which can resolve themselves to ultimately generate the same mature cell type.
A role for BAFF during myelopoiesis (153.25)
Authors: Beaudette-Zlatanova Britte , Yeramilli Venkata , Knight Katherine 
Published: January 2023

Abstract
B cell activating factor (BAFF) is expressed in several tissues including the bone marrow (BM). Although BAFF is important for B cell homeostasis and survival, its effects on other leukocytes has not been elucidated. While studying the role of BAFF in rabbit, we discovered that BAFF binds peripheral blood myeloid cells and MHC Class IIneg CD14neg myeloperoxidase (MPO)pos myeloid progenitors (MP) in the BM. Addition of BAFF to co-cultures of unfractionated rabbit BM cells with the murine BM stroma cell line, OP9 stimulated proliferation of rabbit cells resulting in an increase in the total cell number compared to co-cultures lacking BAFF. In addition, BAFF increased the percentage of CD14pos myeloid cells including macrophages in these co-cultures. To determine if BAFF plays a role in human myelopoiesis, we examined Lineageneg CD13pos MP from cord blood (CB) for BAFF binding and expression of BAFF receptors. We found that a small number of these cells express BAFF receptor and bind BAFF. To elucidate the function of BAFF binding to MP, we cultured MP sorted from CB with thrombopoietin, stem cell factor (SCF), and Flt-3L or with SCF and Flt-3L in the presence or absence of BAFF. Total cell number and the number of myeloid cells expressing CD14, CD15, or Class II was not statistically different in cultures containing or lacking BAFF. Experiments to elucidate the function of BAFF binding to MP cells are ongoing. These data suggest a novel role for BAFF in myelopoiesis.
The TREM-2-β-catenin axis is critical to regulate macrophage colony-stimulating factor proliferation and bone homeostasis (153.29)
Authors: Otero Karel , Cella Marina , Shinohara Masahiro , Mizoguchi Toshihide , Takahashi Naoyuki , Takayanagi Hiroshi , Colonna Marco 
Published: January 2023

Abstract
M-CSF regulates proliferation and survival of mononuclear phagocytes through the CSF-1R. DAP12, an ITAM-containing signaling partner for various myeloid receptors, is also critical for mononuclear phagocyte function. In human, deficiency in DAP12 or the immunoreceptor TREM-2 causes Nasu-Hakola disease (NHD), with bone abnormalities including bone cysts and osteoporosis that lead to bone fractures. Paradoxically, DAP12 is necessary for osteoclastogenesis in the mouse and DAP12-deficient mice exhibit an osteopetrotic phenotype. We have previously shown that DAP12 contributes to M-CSF-induced macrophage proliferation through a pathway that involves β-catenin activation. Here we show that the DAP12-associated receptor responsible for the crosstalk of DAP12 with CSF-1R is TREM-2. M-CSF-induced proliferation is impaired in TREM-2-deficient macrophages, and M-CSF-induced DAP12 phosphorylation, but not basal phosphorylation, is abrogated. In contrast to DAP12 deficiency, mice deficient for TREM-2 or β-catenin in osteoclast precursors show accelerated osteoclastogenesis in vitro and osteoporosis in vivo, recapitulating the bone traits of the human NHD. TREM-2 and β-catenin influence osteoclast development by enhancing the proliferative response of osteoclast precursors, thereby inhibiting their differentiation.
Instructional role of ligand in γδ T cell lineage commitment (153.42)
Authors: Coffey Francis , Lee Sang-Yun , Xiong Na , Zuniga-Pflucker Juan-Carlos , Wiest David 
Published: January 2023

Abstract
The processes that influence alphabeta versus gammadelta T cell lineage commitment are not well defined. Evidence suggests that strength and duration of TCR signaling during T cell development can directly influence fate decisions, irrespective of the TCR isotype. Accordingly, T cell progenitors expressing a gammadelta TCR can be directed toward the alphabeta lineage when signaling through the TCR is attenuated. Previously, we showed that KN6 gammadelta TCR transgenic thymocytes can be directed to the alphabeta lineage when the KN6 TCR ligand, T-10/22, is eliminated. Here we investigate the impact of ligand affinity on cell fate as well as whether it regulates fate selection instructively or stochastically. These issues are addressed in vitro using the OP9 stromal cell model where ligand expression can be manipulated. Our data suggest that differences in ligand expression and affinity are important determinants in fate selection. Moreover, ligand appears to be influencing lineage-fate in an instructional manner and is associated with characteristic changes in gene expression. Understanding how modulating TCR signaling affects T cell lineage commitment will provide insight into pathways that control fate decisions of developing alphabeta or gammadelta T cells.
Immune regulation by mycobacterium via delta-like 4 expression on hematopoietic progenitor cells. (153.7)
Authors: Schaller Matthew , Ito Toshiro , Carson IV William , Kunkel Steven 
Published: January 2023

Abstract
Cells in the myeloid compartment are the first responders of the immune system, and primarily uninfluenced by previous immune responses. This is due to a rapid turnover of the myeloid compartment, with cells constantly arising from the bone marrow. We observed a functional change in the bone marrow of mice exposed to mycobacterium, characterized by decreased ability of bone marrow derived DCs to cause IL-2 production from OT-II cells. This reduction in IL-2 was dependent on the Notch ligand delta-like 4. Additionally, the granulocyte/monocyte progenitor population (GMP) had a higher percentage of cells expressing delta-like 4 in mice exposed to mycobacterium. Transfer of GMP cells from mice exposed to mycobacterium into naïve mice caused a reduction in IL-2 production from T cells during an unrelated immune response. Bone marrow chimeras revealed that progenitors expressing delta-like 4 gave rise to mature myeloid cells in the spleen that also expressed delta-like 4. Splenic DC from CFA primed mice also caused less IL-2 production from OT-II cells via a delta-like 4 dependent mechanism. These studies conclusively demonstrate that respiratory mycobacterium infection can impact on future immune responses by upregulating the expression of delta-like 4 on myeloid progenitor cells, which maintain increased expression as they mature into fully differentiated cells.
The capsid protein of foot-and-mouth disease virus interacts with host toll-like receptor 2 to induce innate immunity (154.14)
Authors: Chang Yu-Ching , Chen Yen-Po , Liang Chi-Ming , Liang Shu-Mei 
Published: January 2023

Abstract
The mechanism of interaction between foot-and-mouth disease virus (FMDV) with the host immune system is not clear. In this study, we investigated the interaction between FMDV and Toll-like receptor 2 (TLR2), an important pattern recognition receptor that regulates host immune function. We found that binary ethylenimine-inactivated FMDV (I-FMDV) activated NF-κB only upon expression of TLR2 but not other TLRs in HEK293T cells. I-FMDV induced IL-6 production in macrophages from wild-type but not TLR2 knockout mice. Coexpression of TLR6 or CD14 with TLR2 markedly enhanced NF-κB activation induced by I-FMDV. Further study indicated that VP1 and VP3 but not VP42, all of which are the capsid proteins of FMDV, are the ligands of TLR2. Co-immunoprecipitation assay also demonstrated that VP1 and VP3 interacted with TLR2 as well as CD14, but not TLR6. These results suggest that TLR6 and CD14 may serve as coreceptors of TLR2 which interacts with VP1 and VP3 of FMDV to induce pro-inflammatory cytokines production and immune responses.
Binding of complement regulator C4b binding protein to Flavivirus Nonstructural Protein NS1 modulates its function in solution and on the cell surface (154.22)
Authors: Avirutnan Panisadee , Hauhart Richard , Somnuke Pawit , Blom Anna , Diamond Michael , Atkinson John 
Published: January 2023

Abstract
The complement system plays an important role in the innate immune response to many pathogens including Flaviviruses. Flavivirus NS1 is a secreted glycoprotein that is absent from viral particles but accumulates at high levels in the blood of infected patients where it may also bind back to the cell surface. Our previous work defined an immune evasion role of Flavivirus NS1 in limiting classical/lectin pathway activation by forming a complex with C1s and C4 to promote the cleavage of C4 to C4b. Herein, we demonstrate a second mechanism by which NS1 antagonizes complement activation. In this case, dengue virus (DENV), West Nile virus (WNV), and yellow fever virus (YFV) NS1 directly associate with C4b binding protein (C4BP), a plasma complement regulatory protein that attenuates the classical/lectin pathway. C4BP is a cofactor for the serine protease factor I to cleave C4b and thereby inhibits classical/lectin pathway C3 convertase (C4b2a) activity. Specifically, binding of NS1 to C4BP results in more efficient factor I-mediated degradation of C4b by C4BP in solution. Furthermore, NS1 recruits C4BP to the surface of cells to inactivate C4b on the plasma membrane. These studies define immune evasion mechanisms by which NS1 reduces C4’s activating capacity. They point to the classical/lectin pathway activation being critical in host defense against Flavivirus infections.
Soluble FasL therapy reduces Herpetic Stromal Keratitis (154.23)
Authors: Stuart Patrick , Rogge Megan 
Published: January 2023

Abstract
Fas ligand (FasL) signals apoptosis in Fas+ cells, and plays a vital role in controlling the entrance of inflammatory cells and neovascularization of ocular tissue. We tested the therapeutic value of soluble FasL in both an acute and recurrent model of HSK using BALB/c and BALB-lpr mice. sFasL was administered in a topical ointment and by subconjunctival injection following infection or reactivation. The controls were treatment with ointment alone or with soluble TRAIL (sTRAIL). These mice were evaluated for corneal disease by a masked observer who scored the corneas for opacity and neovascularization. Following acute infection, wild-type BALB/c mice treated with sFasL displayed reduced incidence of opacity and neovascularization when compared to the sTRAIL and ointment groups post infection. When the Fas deficient BALB-lpr mice were used, results showed no difference in HSK between sFasL and sTRAIL treated groups, as expected. When BALB/c mice undergoing recurrent HSK were treated with sFasL, we saw a decrease in both opacity and neovascularization as compared to the sTRAIL treated mice. These data we believe are due to the apoptotic signaling by sFasL of the Fas molecule found on inflammatory cells and vascular endothelium of newly growing vessels which are attempting to invade the cornea following infection or reactivation.
KLF2 expression modulates susceptibility to HIV-1 infection (154.25)
Authors: Riley James , Richardson Max 
Published: January 2023

Abstract
Here, we show that the transcription factor KLF2 is a host factor with a role in modulating susceptibility to HIV-1 infection. We observed a strong correlation between expression of KFL2 and CCR5. Transformed CD4 T cell lines lack CCR5 as well as KLF2 expression. Forced expression of KFL2 in transformed cell lines induced CCR5 expression and rendered them susceptible to R5 HIV-1 infection, providing insight into why most transformed lines fail to support CCR5 dependent HIV-1 replication. In primary human CD4 T cells, KFL2 expression is rapidly downregulated after T cell activation and is undetectable after anti-CD3/28 costimulation, whereas trace amounts remain after PHA + IL-2 stimulation. This residual amount of KLF2 present after T cell activation correlates well with CCR5 expression and susceptibility to R5 infection. Primary human CD4 T engineered to constitutively express KLF2 retained CCR5 expression and susceptibility to R5 infection after CD3/28 costimulation. These studies implicate KLF2 expression levels present after T cell activation as the determinant of whether a T cell is susceptible to R5 HIV-1 infection. Thus, KLF2 is a host factor that could affect an individual’s susceptibility to HIV-1 infection and the rate by which one progresses to AIDS.