bluuebunny/crossref_metadata_2025_split huggingface dataset:
CD300a binds to phosphatidylethanolamine and phosphatidylserine and modulates the uptake of dead cells. (167.2)
Authors: Borrego Francisco , Andersen John , Calvo Eric , Choi Seung-Chul , Coligan John , Simhadri Venkateswara 
Published: January 2023

Abstract
CD300a is an immuno-receptor tyrosine based inhibitory motif (ITIM) containing molecule that belongs to the CD300 family of paired activating/inhibitory receptors clustered in human chromosome 17. It has been shown that its ligation inhibits activation signals on cells of both myeloid and lymphoid lineages. To identify the ligand of CD300a, we generated an Fc fusion protein containing the extracellular domain of CD300a (CD300a-Ig). We show that CD300a-Ig specifically binds to dead cells that are evolutionary apart, such as human and insect cells, suggesting that the ligand has to be conserved. Using ELISA, ultracentrifugation, surface plasmon resonance, and reporter cell assays we identified phosphatidylethanolamine (PE) and phosphatidylserine (PS), two phospholipids that translocate to the outer leaflet of the plasma membrane of dead cells, as the ligands for CD300a. Our mutational and structural modeling studies identified residues that are involved in the binding of CD300a to PE and PS and that form a cavity where the hydrophilic heads of PE and PS can penetrate. Ectopic expression of CD300a, in the otherwise CD300a negative L929 cells, down-regulated the phagocytosis of dead cells. Furthermore, we also show that CD300a inhibits the uptake of apoptotic cells by human macrophages. Collectively, our results indicate that PE and PS are ligands for CD300a and that these interactions may play an important role in the removal of dead cells by phagocytes.
NDRG2 expression suppresses osteoclast differentiation by down-regulating PU.1 (167.6)
Authors: Lim Jong-Seok , Kang Kyeongah , Yang Young , Lee Myeong-Sok 
Published: January 2023

Abstract
N-myc downstream-regulated gene 2 (NDRG2) has been characterized as a regulator of dendritic cell differentiation. In this study, we show that NDRG2 overexpression inhibits the differentiation of U937 cells into osteoclasts in response to stimulation with LPS, TNF-α, 1α,25-dihydroxyvitamin D3 (1,25D3), or a combination of macrophage colony-stimulating factor (M-CSF) and soluble receptor activator of NF-κB ligand (RANKL). U937 cells stably expressing NDRG2 display reduced tartrate-resistant acid phosphatase (TRAP) activity, as well as defects in F-actin ring formation and resorption pit formation. Furthermore, NDRG2 expression significantly suppresses the expression of genes that are crucial to the proliferation, survival, differentiation, and function of osteoclasts, including c-Fos, Atp6v0d2, RANK, cathepsin K, αv integrin, and MMP-9. Activation of ERK1/2 and p38 is also inhibited by NDRG2 expression during osteoclastogenesis, and the inhibition of osteoclastogenesis by NDRG2 correlates with by down-regulation of the expression of the PU.1 transcription factor. Finally, NDRG2 expression inhibited the differentiation of bone marrow cells and macrophages into osteoclasts, as judged by the failure of these cells to develop giant F-actin rings and resorption pits. Taken together, our results suggest that expression of NDRG2 potentially inhibits osteoclast differentiation and plays a role in modulating the signal transduction pathway responsible for osteoclastogenesis.
miR146a facilitates DENV2 replication by targeting TRAF6 and inhibiting interferon production (168.19)
Authors: Huang Xi , Wu Siyu , Zhang Ping 
Published: January 2023

Abstract
microRNAs (miRNAs) are involved in the regulation of multiple cellular processes and have recently been indicated to modulate the innate immune response. However, the role of miRNAs in dengue virus (DENV) infection remains unknown. Our study test the expression of several innate immune-related miRNAs, including miR-9, 21, 132, 146a and 155, in the monocytic cells after infection with DENV serotype 2 (DENV2). Among these miRNAs, miR-146a expression was significantly increased by DENV2 infection, and its induction was impaired by inhibition of IKK, NF-κB, p38 or JNK mitogen-activated protein kinase (MAPK), or by silencing of interferon-γ promoter stimulator 1 (IPS-1). In addition, our data revealed that miR-146a facilitated DENV2 replication, accompanied by a significantly downregulation of TNFR-associated factor 6 (TRAF6), interferons (IFNs), as well as IFN-stimulated genes. Finally, knockdown of TRAF6 enhanced the DENV2 replication and reduced the IFN production, while overexpression of TRAF6 successfully reversed the proviral effect mediated by miR-146a, suggesting that miR-146a exerts its functions through targeting TRAF6, thereby destroying the IFN and the antiviral state. These findings suggest that miR-146a might be a promising therapeutic target for dengue disease.
Human metapneumovirus impairs the capacity of dendritic cells to prime antigen-specific naïve T cells (168.22)
Authors: Céspedes Pablo , González Pablo , Kalergis Alexis 
Published: January 2023

Abstract
Human metapneumovirus (hMPV) is a respiratory virus that mainly affects infants, the immunocompromised and the elderly. Worldwide, it has been estimated that hMPV is the second cause of upper and lower acute respiratory tract infection in infants causing significant economic burden. Similar to other respiratory viruses, hMPV can repeatedly re-infect the host without major antigenic changes. These observations suggest that hMPV may have evolved molecular mechanisms to interfere with the onset of an adequate host immune response, preventing the establishment of a long-lasting immunological memory. Recent in vitro studies have shown that hMPV infects human dendritic cells (DCs) and decreases their capacity to activate memory CD4+ T cells. However, the mechanisms underlying this reduced T cell activation remain elusive. Here we show that in spite hMPV-infected mouse DCs underwent maturation in response to hMPV, they are rendered inefficient at activating antigen-specific naïve CD4+ T cells. Decreased T cell activation was partially mediated by soluble factors secreted by hMPV-infected DCs and was virus strain-dependent. However, our results suggest inhibition of T cell activation by hMPV-infected DCs is mainly mediated by a cell contact-dependent mechanism. Taken together, our data suggest that hMPV interferes with DC function by soluble and membrane-bound determinants that likely affect T cell activation and the anti-viral adaptive immunity in susceptible hosts.
Human plasmacytoid dendritic cells and myeloid Dendritic cells fuse with chronically HIV-infected T cells (168.23)
Authors: Descalzi-Montoya Dante , Dai Jihong , Singh Sukhwinder , Fitzgerald-Bocarsly Patricia 
Published: January 2023

Abstract
Our laboratory has previously shown that plasmacytoid dendritic cells (pDC) fuse with chronically-HIV infected H9 T cells and also with acutely infected CD4+ primary T cells; a process mediated by virus/CD4 and CXCR4 interactions. In the present study, using the Amnis ImageStream, we observed that fusions can also form between chronically-HIV infected H9 T cells and myeloid dendritic cells (mDC). MDC showed a tendency to form more fusions than pDC. Although the fusion of mDC with HIV-infected H9 T cells was prevented by the CXCR4 inhibitor AMD3100, it was not affected by the CCR5 inhibitor Tak779 or the fusion inhibitor T20. This result indicates gp41 conformational changes may not be involved in this process, but rather it is mediated by CXCR4 interactions. On the other hand, pDC-T cell fusion formation is indeed inhibited by T20 and AMD3100 in our system, indicating that fusion in mDC and pDC may occur via distinct mechanisms. Moreover, there was no difference in induced fusions between pDC and acutely HIV-MN- infected H9 T cells or pDC with AT2-inactivated HIV-MN stimulated T cells, suggesting viral replication is not required for fusion. In conclusion, our observation that non-infectious HIV promotes fusion formation contributes to the notion that HIV bound to the host cell membrane surface may mediate this process. More importantly, in vivo, mDC and pDC fusion with HIV-infected T cells could contribute to the depletion of blood mDC and pDC in HIV-1 infected individuals.
Mouse CMV m153 glycoprotein binds a ligand on dendritic cells (168.28)
Authors: Revilleza Maria Jamela , Mans Janet , Natarajan Kannan , Mage Michael , Carey Rosalene , Boyd Lisa , Margulies David 
Published: January 2023

Abstract
A valuable model for studying virus-host interactions is mouse cytomegalovirus (MCMV), which encodes the m145 family of glycoproteins with predicted MHC-I structure. m153, expressed independently of beta-2 microglobulin and peptide, and is found on the surface of infected cells by flow cytometry. We constructed a reporter cell to identify tissues expressing the ligand of m153 by preparing the DNA encoding the extracellular domains of m153 linked to human zeta chain, and introducing this construct into 43.1 cells that fluoresce green on activation. We identified CD11c+ splenic dendritic cells (DC) and bone marrow DC as potent stimulators. Further characterization of these cells via multi-color staining with an m153 tetramer, and DC markers and antibody blocking experiments suggest a possible candidate for the m153 ligand. This may contribute to our understanding of the steps in virus lifecycle, and shed light on the evolution of viral immunoevasins.
Mechanisms of TRAIL expression by human plasmacytoid dendritic cells (168.29)
Authors: Serei Virian , Dai Jihong , Singh Sukhwinder , Fitzgerald-Bocarsly Patricia 
Published: January 2023

Abstract
One major mechanism of CD4+ T cell decline during HIV infection is due to the death ligand-mediated apoptosis of uninfected CD4+ T cells. TNF-Related Apoptosis Inducing Ligand (TRAIL) is one death ligand involved in this process and is expressed by a number of peripheral blood mononuclear cells upon HIV infection, including plasmacytoid dendritic cells (pDC). The mechanisms of TRAIL expression by pDC still need to be elucidated. To better characterize the expression of TRAIL, pDC were stimulated with TLR7 and TLR9 ligands with or without the addition of brefeldin A (BFA), a Golgi inhibitor. We directly stained pDC for surface TRAIL, and also stained for intracellular TRAIL by permeabilizing pDC with 0.1% Triton-X after overnight fixation with 2% PFA. Flow cytometry analysis revealed that with TLR7 and TLR9 agonists, there was an increase in TRAIL expression on the surface of pDC, while with BFA addition, there was a decrease in surface TRAIL expression accompanied with an increase in intracellular TRAIL expression. Using Amnis Image Stream, we were also able to visualize the location of intracellular and surface TRAIL expression on each pDC. This study showed that upon TLR7 and TLR9 stimulation, pDC upregulate TRAIL expression, and with the addition of BFA, TRAIL is prevented from reaching the surface, accumulating in the cytoplasm of pDC.
Co-stimulatory receptors CD28 and CTLA4 are required for optimal NK cell effector function and memory formation during MCMV infection (168.3)
Authors: Karo Jenny , Sun Joseph 
Published: January 2023

Abstract
Natural Killer (NK) cells are generally classified as a component of the innate immune system. However, recent evidence in mice and humans suggests that NK cells have properties of both innate and adaptive immunity. Optimal T cell activation requires both T cell receptor ligation, a co-stimulatory signal provided by CD28, and regulation by the inhibitory receptor CTLA-4. Although NK cells have been shown to express CD28, the importance of co-stimulation in NK cell responses in vivo has not been previously investigated. Using mice deficient in CD28, and receptor-blocking antibodies, we investigated the role of this receptor on NK cells using a mouse model of cytomegalovirus (MCMV) infection. After primary infection with MCMV, we found that CD28 is necessary for early viral control of MCMV by antigen-specific Ly49H+ NK cells and consequently memory NK cell formation. In addition, we have new evidence that CTLA-4 is highly expressed on activated NK cells during MCMV infection. Surprisingly, like CD28, expression of CTLA-4 was also required for optimal proliferation and function of Ly49H+ NK cells during MCMV infection. Manipulation of these co-stimulatory signals within the immune system is an emerging strategy of effective vaccination and tumor therapy. Therefore, understanding the molecular mechanisms behind effective NK cell responses to pathogens will be critical in our attempts to modulate the immune system against these ailments.
Immune regulation by natural killer cells through lysis of activated T cells (168.4)
Authors: Waggoner Stephen , Welsh Raymond 
Published: January 2023

Abstract
We have previously shown that natural killer (NK) cells can influence viral pathogenesis either by directly lysing virus-infected cells or through lysis of activated CD4 T cells. The latter phenomenon contributed to an inhibition of anti-viral T cells that favored viral persistence and host survival rather than lethal pathology during lymphocytic choriomeningitis virus (LCMV) infection. Infections with unrelated viruses, including Pichinde virus (PV), or inoculation with the type I IFN inducer, polyI:C, also triggered NK cell lysis of activated CD4 T cells. This lysis was coincident with poor control of PV infection and diminished PV-specific memory T cell responses, suggesting that such NK cell immunoregulation is a general principle of virus infection. LCMV infection was unable to induce NK cell lysis of activated T cells in IFN receptor (IFNAR)-deficient mice, implicating type I IFN in stimulation of this NK cell activity. Expression of the CD48, the ligand for the inhibitory NK cell receptor 2B4/CD244, was greater on NK cell-resistant CD8 T cells than their CD4 counterparts. However, genetic deletion of 2B4 facilitated lysis of activated CD8 T cells, and was associated with impaired clearance of both acute and chronic virus infections. Thus, type I IFN expression during virus infection or vaccination stimulates a 2B4/CD48-regulated, NK cell-mediated lysis of anti-viral T cells which impairs viral control and immune memory.
In vivo delivery of lipidoid nanoparticles containing PD-L1 siRNA enhances NK and CD8+ T cell-mediated hepatic antiviral immunity (168.6)
Authors: Dolina Joseph , Sung Sun-Sang , Novobrantseva Tatiana , Hahn Young 
Published: January 2023

Abstract
Effective clinical application of anti-viral immunotherapies necessitates enhancing the functional state of NK and CD8+ T cells. Persistence of viral infections in the liver is established by activation of the PD-1/PD-L1 inhibitory pathway. The expression of PD-1 ligand (PD-L1) is widespread and found on multiple cell types including Kupffer cells, liver sinusoidal endothelial cells, non-resident macrophages, dendritic cells, NK cells, T cells, and hepatocytes. To examine the role of PD-L1 expression by myeloid cells, we determined the magnitude and quality of antiviral immune responses by administering PD-L1 siRNA encapsulated in lipidoid nanoparticles (LNP) in mice prior to or after viral infection. Our studies indicate that Kupffer cells preferentially engulfed PD-L1 LNP leading to specific silencing of Pdl1 during adenovirus and MCMV infection. Treatment of PD-L1 LNP enhanced NK cell and CD8+ T cell intrahepatic accumulation, and depending upon timing of PD-L1 LNP treatment, either NK cell or CD8+ T cell effector function, as assessed by IFN-γ and granzyme B production, were enhanced. Importantly, CD8+ T cell-mediated viral clearance was enhanced through targeted blockade of the PD-1/PD-L1 inhibitory pathway. Our results demonstrate that PD-L1 knockdown on Kupffer cells is central in determining the outcome of liver viral infections. The implications of this research also extend into other diseases including cancer where reversal of CD8+ T cell tolerance is critical.
Therapeutic effect of a CXCR2 ligand acetylated Pro-Gly-Pro against sepsis (169.13)
Authors: Bae Yoe-Sik , Kim Sang Doo , Lee Ha Young , Kim Hak Jung , Baek Suk-Hwan 
Published: January 2023

Abstract
Acetylated Pro-Gly-Pro (Ac-PGP) is an endogenous degradation product of extracellular collagen that binds to leukocyte-expressed chemoattractant receptor CXCR2. Although certain agents that block CXCR2-mediated signaling protect against experimental sepsis, the roles of Ac-PGP and CXCR2 in sepsis are unclear. In this study we investigated the role of Ac-PGP and its receptor, CXCR2, in murine models of cecal ligation and puncture (CLP)-induced polymicrobial sepsis and organ injury. The activation of CXCR2 by Ac-PGP dramatically improved survival in three experimental sepsis models. Ac-PGP elicited bactericidal activity via the generation of hydrogen peroxide, inhibited lung inflammation, and reduced immune cell apoptosis. Fluorescein isothiocyanate-labeled PGP bound directly to CXCR2, and the protective effect of Ac-PGP in sepsis was abolished in CXCR2-deficient mice. Ac-PGP treatment enhanced the production of type 1 cytokines (IFN-γ and IL-12) but inhibited the production of proinflammatory cytokines (tumor necrosis factor [TNF]-α, IL-1β, and IL-6) in vivo. In vitro, Ac-PGP directly increased IFN-γ production and decreased the LPS-stimulated production of TNF-α by mouse splenocytes and human leukocytes. Furthermore, direct treatment of LPS-stimulated splenocytes with IFN-γ resulted in diminished secretion of TNF-α and IL-6. CXCR2 and Ac-PGP are thus novel target and starting molecules, respectively, for the development of therapeutic agents against sepsis.
Acute inflammasome activation and downregulation after severe burn injury in humans. (169.23)
Authors: Maile Rob , Maggin Jeremy , Zihni Ahmed , Sparks Carilyn , Ting Jenny , Cairns Bruce 
Published: January 2023

Abstract
Cytokine activation and the systemic pro-inflammatory shock response following burn injury results in multiple organ failure. We hypothesized that the NLRP3 inflammasome (a multiprotein complex constructed in macrophages following stimulation by danger signals), and related genes are elevated following burn injury in humans. We enrolled 18 patients: 7 with large burns (&gt;30% total body surface area burn, TBSA) and 11 with small burns (&lt; 30% TBSA). Blood was collected at 24, 24-48 and 48-72 hours after burn. Mononuclear cells were harvested, total RNA isolated and levels of NRLP3, Caspase-1, IL-1β, Pyrin and TNFα measured using quantitative real time PCR (qtPCR) and compared to normal pooled mRNA. Serum protein levels of Caspase-1, TNFα and IL-1β were quantified by ELISA and compared to normal serum. At all time points and %TBSA, the relative copy number of Caspase-1 mRNA was significantly elevated but IL-1β mRNA was decreased compared to normal. NLRP3, Pyrin and TNFα mRNA copy numbers were unchanged. Protein levels of active IL-1β, TNFα and caspase-1 were significantly increased at all time points and %TBSA. These data indicate that inflammasome component caspase-1 expression is elevated after burn, cleaving pro-IL1β into the active form. Concurrent downregulation of IL-1β gene expression occurs to counter an overt inflammatory response. This is the first transcriptional evidence of inflammasome activation and homeostatic downregulation in burn patients.
TNFR25SF AND GALECTIN-9 COMBINATION THERAPY REDUCES HERPES SIMPLEX VIRUS-1 INDUCED STROMAL KERATITIS BY EXPANDING REGULATORY T CELLS AND REDUCING PATHOGENIC TH1 CELLS (170.17)
Authors: Jagadeesh Reddy Pradeep Babu , Suryawanshi Amol , Schreiber Taylor , Rajasagi Naveen , Hirashima Mitsuomi , Podack Eckhard , Rouse Barry 
Published: January 2023

Abstract
Ocular infection with HSV-1 results in a chronic immunoinflamammtory reaction in the cornea, which is primarily orchestrated by CD4 T cells. Hence, targeting proinflammatory CD4 T cells or increasing the representation of cells that regulate their function are relevant therapeutic strategies. In the present report, we use an agonistic mAb (4C12) to TNF receptor 25 (TNFR25) that selectively expands numbers of regulatory T cells (Tregs). Treatment early after ocular HSV infection with 4C12 caused a three fold increase in the Treg numbers in the cornea along with a consequent reduction in SK lesion severity. However, 4C12 treatment was less effective if given 6 days after infection since it expanded proinflammatory T effectors that also express TNFR25. To suppress the latter population, galectin-9 (Gal-9) was used which causes apoptosis of Th1 cells. When therapy with both 4C12 and gal-9 was used in combination, the recipients showed significantly reduced angiogenesis and SK lesions over single treatment controls. The beneficial outcome of the combination therapy was attributed to the expansion of the Treg population that expressed CD103 needed for trafficking to inflammatory sites along with a marked reduction in the infiltration of pathogenic CD4 T cells. Levels of several proinflammatory cytokines and chemokines were also reduced. Our results demonstrate that combination therapy may be a promising approach to control HSV induced SK lesions, a common cause of human blindness.
Innate immune response contributes to virus-mediated neuronal death through activation of SARM (170.2)
Authors: Peterson Karin , Woods Tyson , Mukherjee Piyali 
Published: January 2023

Abstract
Neuronal cell death is a hallmark of various neurological diseases including virus infection. The innate immune response in the CNS contributes to neuronal damage through cytokine and neurotoxin production as well as the recruitment of inflammatory cells. However, the role of the innate immune response in the induction of neuronal death is poorly understood. La Crosse virus (LACV), which is a major cause of pediatric encephalitis in the United States, predominantly infects neurons and is associated with neurodegenerative changes. Infection results in neuronal apoptosis. In the current studies we identified sterile alpha and HEAT/Armadillo motif containing 1 (SARM1) protein, a negative regulator of TLR signaling, as a moderator of LACV induced neuronal apoptosis. SARM 1 was induced in neurons following LACV infection and SARM1 knock down studies in neurons demonstrated increased viability during LACV infection as compared to wild-type controls. Direct TLR stimulation of neurons induced SARM 1 which correlated with neuronal apoptosis. Thus, SARM induced as a response to innate immune activation appears to contribute to neuronal death. We are currently investigating the mechanisms underlying SARM induced neuronal death following LACV infection.