bluuebunny/crossref_metadata_2025_split huggingface dataset:
Rap1b-GTPase Regulated Cytokine Generation in murine NK Cells (89.19)
Authors: Awasthi Aradhana , Samarakoon Asanga , Chu Haiyan , Wodnicka Magdalena , White Gilbert C. , Malarkannan Subramaniam 
Published: January 2023

Abstract
Rap1 belongs to Ras superfamily that consists of more than hundred GTP-binding proteins involved in a variety of essential cellular processes. Rap1 exists in two closely related isoforms: Rap1a and Rap1b. Although Rap1 isoforms are known to regulate cell growth, differentiation and survival, their precise functions in lymphocytes have not been defined. In this study, using single gene knockout mice we analyzed the role of Rap1 isoforms in the development and effector functions of natural killer (NK) cells. Both Rap1a and Rap1b are expressed in NK cells and the lack of these GTPases did not affect the development and terminal maturation of NK cells. Moreover, NK–mediated cytotoxicity against ‘missing-self’, ‘induced-self’ and ‘allo’ target cells were not altered by the absence of either Rap1a or Rap1b. However, the ability of NK cells to generate inflammatory cytokines in the absence of Rap1b isoform was significantly reduced. Further, NK cells lacking Rap1a generated normal levels of these cytokines demonstrating the functional divergence between Rap1a and Rap1b isoforms. We conclude that Rap1b is a critical regulator of a signalling pathway that governs the cytokine generation in NK cells.
Plasmacytoid Dendritic Cell Receptor BDCA2/FcεRγ Complex Uses BCR-like Signaling Cascade to Modulate Toll-Like Receptor Responses (89.20)
Authors: Cao Wei , Zhang Li , Rosen David B. , Bover Laura , Watanabe Gokuran , Bao Musheng , Lanier Lewis L , Liu Yong-Jun 
Published: January 2023

Abstract
BDCA2 is a C-type lectin uniquely expressed by human plasmacytoid dendritic cells (pDCs). Ligation of this receptor by mAb inhibits Toll-like receptor (TLR)-mediated type I IFN responses by pDCs. However, it remains unclear how BDCA2 signals. We demonstrate here that BDCA2 forms a receptor complex with the transmembrane adapter FcεRIγ. Furthermore, pDCs express a comprehensive signaling machinery similar to that of the B cell receptor (BCR), which is distinct from that involved in T cell receptor (TCR) signaling. BDCA2 crosslinking resulted in the activation of BCR-like signal cascade in pDCs including phosphorylation of Syk and Src family kinases, as well as adapter molecule BLNK, leading to NFAT activation and calcium flux. This potently suppressed the ability of pDCs to produce IFN and other cytokines in response to both TLR7 and TLR9 ligands. Therefore, BDCA2 negatively regulates pDCs’ innate immune functions by associating with FcεRIγ and activating a BCR-like signaling pathway.
Role of leptin signaling in regulating NK cell development in mouse bone marrow (89.21)
Authors: Lo Cherry Kam Chun , Ko King Hung , Lu Liwei 
Published: January 2023

Abstract
Increasing evidence suggests that leptin is involved in regulating immune response by acting as a growth factor on lymphocytes. Previous studies showed reduced number of NK cells in various peripheral organs of leptin-receptor-deficient db/db mice. However, it remains unknown whether leptin-receptor signaling is involved in regulating NK cell development in the bone marrow (BM). In this study, we characterized NK cell development in the BM of db/db mice at a prediabetic stage. Total number of NK cells was moderately reduced in the BM of mutant mice whereas both frequencies and total numbers of NK cell subpopulations were significantly reduced at various differentiation stages. Moreover, BM NK cells from db/db mice displayed markedly increased apoptosis but did not show any defects in cell cycling status and proliferative capacity. Consistently, recombinant leptin could significantly enhance the survival of NK cells of wild-type mice. To verify if NK cell functional activity was impaired in db/db mice, sorting-purified splenic DX5+CD3− NK cells were evaluated for their cytotoxicity and rmIL-15-induced proliferation capacity. Interestingly, db/db NK cells showed unimpaired capacities in their proliferation and cytotoxic function. In conclusion, our findings demonstrate that leptin-receptor deficiency impairs NK cell development in the db/db mouse BM via affecting NK cell survival.
This work was supported by grants from the Research Grants Council of Hong Kong (HKU7423/04M).
A novel role for HMGB1 in TLR9-mediated inflammatory responses to CpG-DNA (89.24)
Authors: Chu Wen-Ming , Ivanov Stanimir , Dragoi Ana-Maria , Wang Xin 
Published: January 2023

Abstract
Microbial CpG-DNA and related synthetic oligonucleotides (CpG-ODN) activate immune cells to produce inflammatory cytokines through Toll-like receptor 9 (TLR9). TLR9 is an intracellular receptor and is mainly expressed in immune cells. It is proposed that TLR9 is initially localized to the endoplasmic reticulum (ER), and upon movement of CpG-DNA into early endosomes redistributes to CpG-DNA-enriched vesicles, in which it is activated and MyD88 is recruited, leading to subsequent immune responses. However, it is not clear how TLR9 is activated by CpG-DNA, and it remains unknown whether CpG-DNA binding proteins are involved in this activation process. We demonstrate that the high mobility group box 1 protein (HMGB1) is involved in this process. We found that CpG-ODN-treated macrophages and DCs quickly secrete HMGB1; moreover, HMGB1 engaged CpG-ODNs and enhanced their immunostimulatory potential in a TLR9-dependent manner. Confocal microscopy analysis revealed that HMGB1 pre-associates with TLR9, the ER marker calnexin, the ERGIC-53 and the Golgi marker GM130 in quiescent cells, and accelerates redistribution of TLR9 from the ER to the early endosomes in response to CpG-DNA. HMGB1-deficient cells exhibited substantially decreased responses to CpG-DNA, but the defect was complemented by extracellular HMGB1. Thus, the DNA-binding protein HMGB1 shuttles in and out of immune cells, and is important for early endosomal translocation and subsequent activation of TLR9 in response to CpG-DNA.
The Role of Membrane Micro-domains on Target Cells in Control on NK Cell Activity (89.29)
Authors: Gross Catharina Christiane , Long Eric O. 
Published: January 2023

Abstract
Natural killer (NK) cells are large granular lymphocytes that comprise 5–15% of peripheral blood mononuclear cells and function through cytokine production or cytotoxicity. The response of NK cells to contact with other cells is regulated through many different receptor-ligand interactions. Lipid rafts are membrane micro-domains, enriched in glycosphingolipids, sphingomyelins, and cholesterol, which influence receptor signaling in lymphocytes. It is not clear yet to what extent distribution of ligands in micro-domains of target cells controls NK cell responses. To investigate the role of membrane micro-domains on target cells, and to avoid the use of inhibitors such as cyclodextrin, cholesterol-auxotroph insect cells were grown in serum-free conditions to eliminate cholesterol-enriched domains. Insect cells transfected with the GPI-linked CD48 and ULBP1 molecules, ligands for 2B4 and NGK2D respectively, are currently being tested for their ability to activate NK cells.
Estrogen Deficiency Induces Bone Loss in Mice Lacking ITAM Adapter Proteins, DAP12 and FcRg (89.31)
Authors: Wu Y. , Torchia J. , Yao W. , Lane N. E. , Lanier L. L. , Nakamura M. C. , Humphrey M. B. 
Published: January 2023

Abstract
DAP12 and or FcRγ ITAM signals are required during normal osteoclast (OC) development in vivo and in vitro. To determine whether ITAM deficient mice are resistant to bone loss induced by estrogen deficiency, we performed ovariectomy (OVX) or SHAM surgery on 10–12 week female DAP12−/−, FcRγ−/−, DAP12−/−FcRγ−/− and control C57BL/6 (B6) mice. MicroCT of the distal femur showed statistically significant losses of trabecular bone in DAP12−/−FcRγ−/−, DAP12−/−, FcRγ−/− and B6 OVX groups compared to SHAM groups, BV/TV dropping from 56% to 35% (p&lt;0.01), 21% to 12% (p&lt;0.01), 12% to 7% (p&lt;0.01), and 6% to 3% (p&lt;0.05) respectively. Bone turnover measured by serum osteocalcin and urinary DPD increased at 4 weeks post-OVX in all four strains. In vitro OC bone resorption assays revealed a 2.7 or 3.6 fold increase in OC resorption from B6 and FcRγ−/− OVX mice that were not seen in DAP12−/− and DAP12−/−FcRγ−/− OVX OC. FSH, reported to stimulate postmenopausal osteoporosis, combined with RANKL could not rescue the in vitro OC defect in DAP12−/− and DAP12−/−FcRγ−/− cultures. TGB-β followed by TNF-α stimulation induced OC differentiation in B6 cells in vitro without RANKL; however, DAP12−/− and DAP12−/−FcRγ−/− OC cultures were not rescued. We conclude that OC differentiation during estrogen deficiency induced osteoporosis bypasses the requirement of ITAM signaling and the unidentified novel effect is microenvironment dependent.
D-3-deoxy-dioctanoyl-PI induces cell death in the human leukemic monocyte lymphoma cell line U-937 by disruption of the phosphatidylinositol 3-kinase (PI3K)/Akt pathway (89.33)
Authors: Blair Derek , Pu Mingming , Wang Yanling K. , Chen Wei , Xu Yingju , Miller Scott J. , Roberts Mary F. , Chiles Thomas C. 
Published: January 2023

Abstract
D-3-deoxy-phosphatidylinositol derivatives have a potentially wide array of targets in the phosphatidylinositol 3-kinase (PI3K)/Akt signalling pathway. As such, these phosphatidylinositol molecules have been shown to have cytotoxic activity against a variety of human cancer cell lines. Here, we demonstrate that the D-3-deoxy-dioctanoyl-PI (D-diC8PI), but not the L-isomer or D-3,5-dideoxy-diC8PI, is able to induce the death of the U-937 human leukemic monocyte lymphoma cell line, even at low concentrations (&lt;50 μM). In order to further investigate the mechanism of the cytotoxicity of D-3-deoxy-diC8PI we examined its effect on the activity of various molecules in the PI3K/Akt pathway. In vitro, low concentrations (&lt;50 μM) of D-3-deoxy-diC8PI have no significant effect on the activity of PI3K or PTEN. However, incubation of U-937 cells with D-3-deoxy-diC8PI at these concentrations results in significant decreases in phosphorylation of key components of the PI3K/Akt signalling pathway, including the transcription initiation factor eIF4e and the translation factor S6 ribosomal protein. These data further delineate the mechanism of action of such cytotoxic D-3-deoxy-PI compounds.
A novel in vivo siRNA delivery technology for dendritic cell-specific gene silencing and immune modulation (89.5)
Authors: Vladau Costin , Zheng Xiufen , Zhang Xusheng , Li Mu , Suzuki Motohiko , Chen Dong , Garcia Bertha , Min Wei-Ping 
Published: January 2023

Abstract
Silencing immune molecules, such as the costimulatory molecule CD40, using siRNA was shown to have therapeutic potential and promise in immune modulation. However, a major barrier to the clinical application of siRNA is the current lack of an effective and cell-specific delivery system. Herein, we present a new method of selectively delivering siRNA to DC in vivo using stealth immunoliposomes (SILs). CD40 siRNA-containing SILs were generated using 4 types of lipids and decorated with surface-bound, DC-specific mAbs. DC-specific binding capacity of SILs was demonstrated by fluorescence microscopy and flow cytometry. Upon treatment with CD40 siRNA-SILs, DC expression of CD40 was successfully suppressed in vitro. Administration of CD40 siRNA-SILs resulted in DC-specific tissue targeting, as evidenced by increased uptake of fluorescence-tagged siRNA. Additionally, DC from mice treated with CD40 siRNA-SILs exhibited CD40-specific gene silencing in vivo. Tolerogenic properties of DC treated with CD40 siRNA-SILs were determined by inhibition of allogeneic T cell proliferation in MLR. Furthermore, a strong in vivo immune modulation was observed in mice treated with CD40 siRNA-SILs. In conclusion, this is the first demonstration of DC-specific siRNA delivery and gene silencing in vivo, which highlights the potential of DC-mediated immune modulation and the feasibility of siRNA-based clinical therapy.
CpG oligodeoxynucleotide and double-stranded RNA synergize inflammatory cytokine gene expressions in chicken monocytes (90.13)
Authors: He Haiqi , Genovese Kenneth J. , Kogut Michael H. 
Published: January 2023

Abstract
Toll-like receptors (TLRs) recognize microbial components and initiate innate immune responses that control microbial infections. We have investigated the innate immune response of chicken monocytes to CpG-motif containing oligodeoxydinucleotide, CpG-ODN, and the analog of viral double-stranded RNA, poly I:C. Our results show ligands poly I:C and CpG-ODN of the TLR3 and TLR9, respectively, synergized the induction of many genes involving inflammatory responses including nitric oxide and cytokines, IL-1&#946;, IFN-&#945;, IFN-&#946;, IFN-&#947;, IL-18, and IL-12, in chicken monocytes. We also demonstrated the differential responses of some cytokines such as IL-18 and IFN-&#946; to CpG-ODN and poly I:C stimulations, respectively. Those results demonstrate differential roles for TLR3 and TLR9 in signaling immune responses to bacterial and viral infections in chicken monocytes as well as a synergistic interaction between the two signaling pathways. Furthermore, our results suggest synergistic interaction between TLR3 and TLR9 pathways may contribute the “lethal synergism” from bacterial and viral co-infections.
Activation of OX40 down-regulates IL-17 production (91.10)
Authors: Li Jian , Shang XiaoZhou , Li Lily , Schantz Allen , Bracht Michelle , Benson Jacqueline , Elloso Merle , Orlovsky Yevgeniya , Sweet Ray 
Published: January 2023

Abstract
IL-17 is an important cytokine involved in multiple inflammatory diseases partially through the up-regulation of various pro-inflammatory cytokines and chemokines. The regulation of IL-17 production has been well studied, but the role of OX40 on IL-17 regulation has not been fully illustrated. In this study, we investigated the effect of activation of OX40 on IL-17 production. As expected, stimulation of PHA activated human peripheral blood mononuclear cells (PBMCs) with soluble OX40L increased both Th1 (IFNγ) and Th2 (IL-4 and IL-13) cytokine production. However, addition of soluble OX40L significantly inhibited IL-17 production, and this inhibition was abrogated by IFNγ mAb. IL-23 is a major stimulator for IL-17 and IL-23 enhanced IL-17 production was also inhibited by soluble OX40L in purified human CD4 and CD8 T cells. The downregulation of IL-17 by activation of OX40 was also demonstrated in murine splenocytes from OVA TCR transgenic mice. Blockage of OX40/OX40L interaction with either OX40L antibody or mouse OX40/Fc protein enhanced IL-17 production. In addition, agonistic OX40 antibody inhibited antigen induced IL-17 production and antagonistic OX40 antibody enhanced IL-17 production in splenocytes from OVA transgenic mice. Taken together, our results show that activation of OX40 exerts a negative regulation on IL-17 production. The inhibition is probably mediated through the up regulation of IFNγ production.
Preformed CD40 ligand exists in secretory lysosomes of effector and memory CD4 T cells and is recruited to the cell surface upon antigenic stimulation (91.2)
Authors: Koguchi Yoshinobu , Thauland Timothy J , Slifka Mark K , Parker David C 
Published: January 2023

Abstract
CD40 ligand (CD40L) is essential for the establishment of humoral and cellular immunity. Although its functions are well characterized, little is known about the regulation of its surface expression because of CD40-mediated modulation. Intracellular staining shows that most CD40L in resting, effector CD4 T cells is intracellular (iCD40L). We used a surface mobilization assay, in which the detection antibody is included during stimulation to enhance sensitivity, to show that iCD40L comes to the cell surface within 30min upon stimulation in a cycloheximide-insensitive manner. Microscopic analysis demonstrated that iCD40L is co-localized with Fas ligand but not with CTLA-4 in secretory lysosomes. We also found that LCMV-specific effector and memory Th1 cells have iCD40L, which comes to the cell surface upon antigen recognition. Finally, we observed that both naïve and effector/memory CD4 T cells from unmanipulated animals contain iCD40L, while only effector/memory T cells exhibit rapid surface mobilization of iCD40L. Surface mobilization of iCD40L is observed in T cells from CD40-deficient mice, indicating that CD40 is not required for sorting of CD40L to secretory lysosomes. Our results suggest that effector CD4 T cells can provide CD40-mediated stimulation to antigen bearing APCs by delivering iCD40L during transient interactions.
This work was supported by Grant AI29544 from the NIH.
The Wiskott-Aldrich Syndrome protein (WASp) controls Th2, not Th1, effector function in vivo (91.6)
Authors: Morales-Tirado Vanessa Marie , Katzman Shoshana , Fowell Deborah 
Published: January 2023

Abstract
Signals through the TCR and cytokine receptors cooperate to direct uncommitted CD4+ T cells into Th1 and Th2 cells. The signals required for the acquisition of Th effector function are poorly understood. Remodeling of the actin cytoskeleton is essential for the transduction of signals from external stimuli, translating into morphological changes, polarity and reorganization of proteins for the formation and stabilization of the immunological synapse (IS). The Wiskott Aldrich Syndrome protein (WASp) is a key regulator of the actin cytoskeleton, suggested to be the link between TCR signals and cytoskeletal reorganization. However, it is unclear how these initial signaling events modulate cell fate decisions for effector function.
We investigated the role of WASp during the Th cell differentiation by using WASp−/− CD4+ T cells. We identified two distinct WASp-dependent control points in vitro: regulation of cytokine gene transcription and regulation of targeted cytokine secretion. For Th2 development, we observe defects in signals for sustained IL-4 gene transcription. In contrast, Th1 development is WASp-independent. Although WASp−/− cells contain similar levels of intracellular IFN□ when compared to WT cells, we observe a defect in cytokine polarization to the IS for directed secretion. The final secretion of both Th1 and Th2 cytokines is severely impaired. In vivo the major defect appears to be in Th2 function. The outcome of these studies could provide possible explanations for the pathology observed in human WAS-patients, characterized by eczema, thrombocytopenia and immunodeficiency. NIH T32 AI007362
Lung RNA profiling suggests an essential role for micro RNAs in regulating allergic lung disease (91.9)
Authors: polikepahad sumanth , El-Daye Jad , Naghavi Arash , Miller Jonathan , Gunaratne Preethi , Corry David Brian 
Published: January 2023

Abstract
MicroRNAs (miRNAs) are small non-coding RNAs, which negatively regulate gene expression by translational inhibition of target mRNAs. In vertebrates, miRNAs are produced in most organs, including lungs. In the current study, we hypothesized that the expression of miRNAs would correlate inversely with expression of critically important target genes involved in the pathogenesis of allergic lung disease. After intranasal challenge of mice with a potent allergen derived from Aspergillus oryzae on alternating days for 2 weeks, lungs were isolated, high quality RNA was extracted and subjected to microarray analysis in comparison to naïve lungs obtained in parallel. In allergic lungs, ~ 30 known miRNAs were suppressed and ~100 were induced, including many new miRNA candidates uncovered through genome-wide predictions. Bioinformatics analysis revealed that miRNA 199a*, which was suppressed, and miR-144 which was induced in allergic lungs, are candidate regulators of STAT-6, GATA-3 and costimulatory factors, all of which are critical mediators of allergic lung disease. These studies suggest the existence of many new miRNAs and pivotal role for miRNA 199a* in controlling the expression of allergic lung disease.
Germinal center helper T-cells are dual functional regulatory cells with suppressive activity to conventional CD4+ T-cells (92.1)
Authors: Zheng Biao , Marinova Ekaterina , Han Shuhua 
Published: January 2023

Abstract
Germinal center (GC) reaction is a T cell-dependent process in which activated B cells mature to produce high-affinity antibodies and differentiate into memory B cells. The GC microenvironment is almost exclusively reserved for the optimal antigen-specific B cell clonal expansion, selection and maturation, but lack of significant conventional CD4+ T- cell responses. The mechanisms that ensure such a focused B cell response in the GC are not known. Here we report that human CD4+CD57+T-cells, which are the major helper T-cells in GCs, actively suppress the activation of conventional CD4+ T-cells, particularly Th1 cells, via direct contact-dependent mechanism and soluble mediators. Our findings demonstrate that GC T-cells are unique regulatory cells that provide critical help signals for B-cell response but suppress conventional effector T-cells in the same local environment.
Redistribution of Lipid-rafts to T Cell –Antigen Presenting Cell Contact Is Not a Prerequisite for CD4 T Cell Activation (92.13)
Authors: Yang Wen , Xu Yanfei 
Published: January 2023

Abstract
During T cell activation, lipid-rafts were reported to be polarized in the contact area of T cells and antigen presenting cells (APCs) in the literature. Whether such polarization of lipid rafts is a prerequisite for T cell activation is still unclear. To address this question, we studied the distributions of lipid-rafts in naive murine T cell receptor transgenic CD4 T cells upon engaging APCs presenting peptide antigen, under conditions that the T cells were untreated, pretreated with GM1-binding reagent chorela toxin B (ctB), or pretreated with ctB followed by crosslinking with anti-ctB antibodies (ctB+actB). In consistent with findings reported in the literature, lipid-rafts, as indicated by GM1, were concentrated in the contact sites between untreated T cells and APCs in the presence of antigen. In contrast, GM1 was polarized to the opposite end of ctb+actB-treated T cells, the urope. The redistribution of GM1 to the T-APC contact and/or the urope of T cells was less obvious in the ctB-treated-only T cells, but to the latter was significantly enhanced within minutes of adding the actB to the T cells previously engaged with APCs presenting antigen. However, under these conditions with or without GM1-pretreatments, no detectable inhibition on T cell activation was observed as assayed by secretion of IL-2 and T cell proliferation. Results from this study clearly indicated that redistribution of GM1, a lipid-raft marker, to the T-APC contact site is not essential for CD4 T cell activation.