bluuebunny/crossref_metadata_2025_split huggingface dataset:
Macrophage phagocytosis and lysozyme-based digestion of peptidoglycan are required for IL-1β production in response to S. aureus (134.38)
Authors: Underhill David M. , Shimada Takahiro , Park Bong Goo , Goodridge Helen S. , Wolf Andrea J. , Becker Courtney , Reyes Christopher , Götz Friedrich , Liu George Y. 
Published: January 2023

Abstract
IL-1β produced by phagocytes is important for protection against Staphylococcus aureus, a bacterium that causes serious skin and invasive diseases and is contributing to a current public health crisis due to the emergence of methicillin-resistant strains. Secretion of IL-1β requires both activation of a transcriptional signal to stimulate production of pro- IL-1β, (usually provided by TLR signaling) and a second signal to stimulate processing by inflammasome complexes and release of the mature cytokine. We show here that phagocytosis and lysozyme-based degradation of bacterial cell walls are functionally coupled to activation of Nalp3 inflammasomes and secretion of IL-1β in response to live S. aureus and to S. aureus peptidoglycan. Further, a S. aureus peptidoglycan-modifying enzyme that makes its peptidoglycan resistant to lysozyme strongly suppresses inflammasome activation. This is the first demonstration of a case whereby a bacterium avoids IL-1β secretion through chemical modification of its cell wall peptidoglycan, and we hypothesize that this reduced IL-1β production is key to successful mucosal colonization and infection.
This research is supported by grants from NIGMS and the American Heart Association.
Regulation of Murine Splenic B Cell Complement Receptor 3 Expression by Complement Component C3 (134.57)
Authors: Jacobson Amanda  C , Weis Janis J , Weis John H 
Published: January 2023

Abstract
Complement component C3 has established roles in both innate and adaptive immune responses. C3 cleavage products function in B cell activation through the complement receptors CD21/35. Phenotypes involving antibody production between CD21/35-/- and C3-/- mice are not always congruent, implying additional roles for C3 in B cell responses. To further characterize complement and complement receptors, we have identified a role for C3 in the regulation of CR3 on splenic B cells. Splenic B2 cells are not defined as expressing CR3 (as opposed to peritoneal cavity B1 B cells) yet the analysis of splenic B cells from C3KO animals demonstrated cell surface expression of CR3. B cells from WT and C3KO animals both express the Cr3 gene indicating that the lack of CR3 on WT B cells is not due to a deficiency of the transcript/protein. C3KO and WT animals have similar B cell sub-populations as well as identical CR3 expression on macrophages and neutrophils. The C3-deficient environment was responsible for altered CR3 expression as WT splenic B cells transferred into C3KO animals expressed cell surface CR3 within 48hrs while transfer of C3KO splenic B cells into WT animals extinguishes surface expression of CR3. Furthermore, transfer of C3-producing splenic macrophages into C3KO mice depressed CR3 expression by resident B cells. These data suggest a rapid turnover of CR3 on splenic B cells due to C3-bound complexes and the loss of CR3 on such cells may alter the function or localization within the splenic architecture.
NIH-AI-2458 to JHW and NIH-AI-32223 to JJW
Inactivation of the MiRNA-processing enzyme Dicer impairs NK cell responses in vitro and in vivo (134.6)
Authors: Bezman Natalie , McManus Michael T , Lanier Lewis L 
Published: January 2023

Abstract
Natural killer (NK) cells are specialized lymphocytes of the innate immune system that can recognize and eliminate transformed and virus-infected cells. Although the transcriptional and signaling networks that modulate activation of NK cells have been intensely studied, less is known about the post-transcriptional mechanisms that regulate NK cell function. MicroRNAs (miRNAs) have recently emerged as critical regulators of the differentiation and function of many cell types. We hypothesize that miRNA-mediated gene regulation is critical for the activation and function of NK cells. To this end, we generated a mouse strain with tamoxifen-inducible disruption of Dicer, the endonuclease responsible for miRNA processing. Tamoxifen administration efficiently induced Cre-mediated recombination of Dicer in various lymphocyte lineages, including NK cells. Our studies suggest that lack of miRNAs following Dicer inactivation leads to reduction in the number of mature NK cells in spleen and liver. Freshly isolated Dicer-deficient NK cells exhibited reduced proliferation in response to IL-2 and showed impaired cytokine production after stimulation of the activating receptors NK1.1, Ly49H, and Ly49D. Ongoing studies investigate whether miRNAs are necessary for NK cell activation and expansion to MCMV infection in vivo.
Peripheral blood monocytes express surface C1q and its orientation may dictate early events of monocyte to dendritic cell differentiation (134.62)
Authors: Hosszu Kinga K , Santiago-Schwarz Frances , Peerschke Ellinor I.B. , Ghebrehiwet Berhane 
Published: January 2023

Abstract
C1q is a collagen-like glycoprotein comprising two functionally distinct regions–collagen tail (cC1q) and globular heads (gC1q). Our earlier experiments showed that C1q regulates monocyte to DC differentiation by suppressing DC development at the earliest stages. This suggested that C1q may be expressed on monocytes, and through interactions with C1qRs, could regulate early signals that lead to differentiation. Using ELISA and flow cytometric analysis, we confirmed the surface expression of C1q on fresh monocytes, and the level could be sustained beyond day 3 when monocytes were cultured with a mono-macrophage specific growth factor (M-CSF). In the presence of DC growth factors (GM-CSF+IL-4) however, surface expression rapidly declined coinciding with firm commitment to the DC lineage on day 3. Anti-gC1q IgG bound only to macrophages but not to monocytes or immature DCs, suggesting that C1q is bound to monocytes via gC1q, whereas on macrophages it is anchored via cC1q. Thus the orientation of surface C1q may dictate regulation of the early processes that signal progression from the monocyte lineage (innate) towards the DC lineage (adaptive immunity). More importantly, since M-CSF is a normal constituent in the blood, the expression of C1q on fresh monocytes may reflect an M-CSF/C1q coupled regulatory process operating to maintain steady state. [Supported by NIH Grant R01 AI-060866 (to BG) and R03 AR-05396 (to FSS)]
HCV Core/gC1qR Interaction Regulates LPS-Mediated MAPK Activation (134.66)
Authors: Tacke Robert S , Waggoner Stephen N , Tosello-Trampont Annie , Hahn Young S 
Published: January 2023

Abstract
Hepatitis C Virus (HCV) is a dangerous human pathogen that is able to establish chronic infection in its host. Studies of the immune response to the virus reveal a weak and severely delayed T and B cell response. HCV core protein is the first viral protein made following infection within hepatocytes. In addition to forming the viral capsid, HCV core protein is secreted from infected hepatocytes and is present at high levels in the peripheral blood of infected individuals. Previous data from our laboratory has shown that extracellular HCV core protein binds complement receptor gC1qR. This interaction results in the suppression of LPS-mediated IL-12 production in a PI3K dependant manner in human monocytes. Here we show that signaling through the gC1qR results in the suppression of LPS-mediated MAPK activation in a PI3K-dependent fashion. Further, we show that gC1qR-mediated signaling activates AKT, and that AKT is able to phosphorylate GSK-3β and MAPKKK family protein ASK1 at serines 9 and 83 respectively. Phosphorylation at these sites results in reduced activity of both kinases. Interestingly, both GSK-3β and ASK1 are important for LPS-mediated IL-12 production. These results suggest that HCV core protein binds gC1qR on the surface of human monocytes resulting in the activation of the PI3K/AKT pathway. AKT then inhibits LPS-mediated GSK-3β and ASK1 activation resulting in impaired MAPK activation and IL-12 production. NIH Grant RO1AI057591 supported this research.
C5b-9 inhibits myelin gene expression in oligodendrocyte progenitor cells (134.68)
Authors: Tegla Cosmin A , Ito Takahiro , Cudrici Cornelia , Rus Horea 
Published: January 2023

Abstract
Active demyelinating multiple sclerosis (MS) lesions can be subdivided into four neuropathological patterns, based on the presence of immunoglobulins and C5b-9 or evidence of primary oligodendrocyte pathology. Following inflammatory demyelination only partial remyelination occurs and is mediated by oligodendrocyte precursor cells (OPCs). No systematic studies were performed to localize the OPCs in relation to the C5b-9 deposits in MS brains. OPCs we identified by immunohistochemistry using antibodies against NG2, an integral membrane chondroitin sulfate proteoglycan. In addition we examined the deposition of C5b-9 and the presence of inflammatory cells. We detected NG2+ cells in both perivascular and parenchymal areas of MS plaques and normal adjacent white and gray matter areas. A subpopulation of NG2-positive cells also presented C5b-9 deposits and suggests that the terminal complement complex might be involved in OPCs differentiation. To test this hypothesis we investigated in vitro the effect of sublytic C5b-9 on OPC differentiation and expression of myelin genes. Sublytic C5b-9 significantly reduced the accumulation of mRNA encoding proteolipid protein and myelin basic protein. These data are the first to implicate the C5b-9 in the limited remyelination seen in MS lesions. Thus, C5b-9 assembly may represent a potential target for therapeutic intervention in MS.
Impact of NADPH Oxidase Inhibition on Influenza A Virus-induced Inflammation (134.80)
Authors: Patel Jenish R. , Christoph Bradley T. , Hussain Sakina F. , Vora Keyur P. , Ranjan Priya , Sambhara Suryaprakash , Gangappa Shivaprakash 
Published: January 2023

Abstract
Activation of innate immunity pathways in susceptible cell types is critical for host defense against influenza-A viruses (IAV). Based on studies signifying a role for NOX1 in inflammation, we hypothesized that IAV of seasonal and pandemic potential may induce different isoforms of NOX enzymes in the respiratory tract, and that attenuation of virus strain-specific NOX enzymes can be exploited to prevent and/or treat severity of disease. Using three respiratory tract-relevant cell lines (epithelial/A549, endothelial/HULEC, and monoctytic/THP1) and three strains of IAV (H1N1/PR8, H3N2/X31, H1N1/WSN), we found significant upregulation of NOX1 in all three cell lines (e.g.-A549: PR8/55 fold; X31/35 fold; WSN/12,250 fold). Furthermore, in contrast to the epithelial cell line showing NOX1 expression by 4h with peak levels at 16h, the monocytic cell line showed delayed (8h) and sustained (48h) levels of NOX1. Interestingly, inhibition of NOX-isoforms in IAV-infected epithelial cells by diphenyleneiodonium (DPI), at a concentration (25μM), which did not impact cell death, showed significant decrease (75%) in virus triggered NOX1 levels. In addition, NOX-inhibition led to significant decrease in virus-induced chemokines (MCP1, MIP3, MIP1β, RANTES, and IP10) and proinflammatory cytokines (IL1α, IL6, IL8, and TNFα). Furthermore, decline in NOX1 correlated with a modest increase in viral NS1. Taken together, in addition to showing definitive evidence for upregulation of NOX1 in response to subtypes of IAV, our results strongly support a role for NOX1 in IAV-driven inflammation.
Vasoactive intestinal peptide 10-28 enhances natural killer cell cytotoxicity (134.84)
Authors: Suck Garnet , Veljkovic Veljko , Chu Sixian , Niam Madelaine , Tan Suet Mien , Branch Donald R. , Koh Mickey B. C. 
Published: January 2023

Abstract
Objective: Vasoactive intestinal peptide (VIP) and its synthetic analog VIP14-28 enhance NK cytotoxicity. This prompted us to study interaction of the naturally occurring peptide and orphan ligand VIP 10-28 with NK.
Results: VIP10-28 stimulation (10-8-10-10 M, 30 min.) increased NK-92 cytotoxicity against K562 max. from 52% +/-2.6% SEM (control) to 68% +/-2.6% SEM (E:T 1:1), similar to long-term IL-2 stimulated NK from different donors (4/6), max. from 38% +/-4.2 SEM (control) to 51% +/-0.9% SEM (E:T 1:1). VIP10-28 did not seem to induce degranulation, since granzyme B levels remained unchanged in NK-92. However, stimulation with 10-8-10-10 M VIP10-28 for 5- 60 min. significantly induced tyrosine phosphorylation with ERK identified as one of the stimulated kinases. We used Informational Spectrum Method (ISM) to predict VIP10-28 NK receptor interactions. ISM results suggested potential binding of VIP10-28 to LFA-1α (F = 0.03, peptide residues 16-24) and with lower affinity to CD44 or MAC-1, but unlikely to NKG2D, -C, -A, NKp30, -44, -46, CD56, CD94, KIR2DL4, NKR-P1, CD45 or VIP receptors VPAC-1/ VPAC-2.
Conclusion: The neuroendocrine peptide VIP10-28 induces increased NK cytotoxicity potentially through LFA-1 signaling pathways involving tyrosine kinase activation of ERK kinases.
Enhanced immunity following ingestion of plant derived polysaccharides (134.87)
Authors: Hedges Jodi F. , Rask Kerri M. , Jutila Mark A. 
Published: January 2023

Abstract
Considering the recent increased interest in dietary supplements by the public, characterization of their mechanisms and safety are warranted. Yamoa(tm), bark from the Funtumia elastica tree, has anecdotal positive effects in asthma patients. We have determined that polysaccharide components of Yamoa(tm) and other dietary supplements stimulate innate immunity similarly to LPS, in part by affecting γδ T cells. We hypothesized that orally administered Yamoa(tm) would effectively target this mucosal T cell subset and result in changes in peripheral and tissue-associated immune cells, and provide benefit in mucosal disease settings. Increases in an inflammatory subset of γδ T cells, and B cells were detected in peripheral blood in bovine calves fed Yamoa(tm). Cannulation of the efferent lymphatic ducts of the gut in calves was used to analyze the responses of tissue-derived cells after ingestion of Yamoa(tm). Therapeutic treatment of mice by i.p. injection of Yamoa(tm) and its derived polysaccharides was effective in reduction of fecal CFUs in a mouse model of Salmonella-induced enterocolitis. Interestingly, whereas long term ingestion of low doses of polysaccharides had neutral or negative effects on CFUs in this model, a single prophylactic oral dose of Yamoa(tm) resulted in decreased CFUs. These data suggest that the practical and relevant route of ingestion of plant-derived polysaccharides can affect innate immunity.
How is the diacylated lipopeptide FSL-1 processed after recognition by TLR2 ? (135.1)
Authors: Haque Mohammad Shamsul , Hasebe Akira , Iyori Mitsuhiro , Kiura Kazuto , Ohtani Makoto , Shibata Ken-ichiro 
Published: January 2023

Abstract
The diacylated lipopeptide FSL-1 is recognized by TLR2/TLR6, but it still remains unclear how FSL-1 ligands are processed after recognition. Nystatin had no effect on the FSL-1 uptake by macrophages, whereas both chlorpromazine and methyl-β-cyclodextrin inhibited the FSL-1uptake. Intenalization of FSL-1 was downregulated by knockdown of clathrin mRNA. These results suggested that FSL-1 was found to be internalized into the cells by a clathrin-dependent endocytosis. In addition, it was found that FSL-1 was not colocalized with TLR2 in the cytosol, and there were no differences in the level of FSL-1 uptake by peritoneal macrophages from TLR2+/+ and TLR2-/- mice. FSL-1 stimulation induced downregulation of the surface expression level of TLR2, suggesting that FSL-1 stimulation is required for the internalization of TLR2. Thus, this study demonstrated that FSL-1 was internalized into macrophages in a clathrin-dependent manner and TLR2 was not required for the internalization, although FSL-1 stimulation was required for internalization of TLR2. In addition, HEK 293 cells stably expressing CD14 or CD36, but not HEK293 cells, were involved in the uptake of FSL-1 by macrophages, suggesting that they function as an endocytic receptor for FSL-1 as well as a coreceptor of TLR2.
Activation of MyD88-mediated Signaling by MHC Class II Ligands Stimulates Inflammation (135.22)
Authors: Fernandez Stefan , Kissner Teri L , Ruthel Gordon T , Ulrich Robert G , Kamal Saikh U 
Published: January 2023

Abstract
Agonists binding to Toll-like receptor (TLR) or interleukin 1 receptor (IL-1R) activate MyD88-mediated signaling, which leads to pro-inflammatory responses. Here we report that MyD88 also mediates a component of intracellular signaling initiated by MHC class II, receptor-ligand interactions. Treating human primary monocytes with staphylococcal enterotoxin A (SEA), SEB, or anti-MHC class II monoclonal antibodies up-regulated MyD88 expression, increased expression of IL-1R1 accessory protein, induced activation of NF-kB and the subsequent release of pro-inflammatory cytokines. Similar to MHC class II activation of monocytes in isolation, (i.e., in the absence of T cells) MyD88-mediated pro-inflammatory cytokine expression was observed in primary monocytes selected after stimulation of peripheral blood mononuclear cells with SEA or SEB. Consistent with these results, increased secretion of pro-inflammatory cytokines was also observed in MHC class II + murine spleen cells. This effect was drastically reduced in MHC class II+, MyD88-deficient spleen cells. Importantly, stimulation of primary human monocytes or monocytic cell lines with SEB or lipopolysaccharide induced translocation to the membrane, de novo synthesis, and tyrosine phosphorylation of MyD88. These results demonstrate a MyD88-mediated signaling mechanism for MHC class II, which induces expression of genes encoding pro-inflammatory cytokines.
Regulation of Macrophage Activation by a Novel Splice Variant of the Voltage-gated Sodium Channel NaV1.5 (135.27)
Authors: Carrithers Michael , Carrithers Lisette 
Published: January 2023

Abstract
Novel splice variants of the voltage-gated sodium channels, NaV1.5 and NaV1.6, are expressed in human monocyte-derived macrophages and THP-1 cells, a human monocytic cell line. Our prior work demonstrated that macrophage NaV1.5 localizes to the late endosome in primed human macrophages and differentiated THP-1 cells and regulates endosomal acidification and phagocytosis. Here we show that macrophage NaV1.5 regulates intracellular signaling associated with cell priming. THP-1 cells that express NaV1.5 (wild type and control shRNA cells) and those that do not (NaV1.5 shRNA-mediated knockdown) were differentiated with phorbol ester for 3 days and then primed sequentially with interferon-gamma and LPS. Analysis of global mRNA expression using Affymetrix oligonucleotide arrays demonstrated decreased expression of several inflammatory response genes and increased expression of a pro-survival growth factor in NaV1.5 knockdown cells. These results were confirmed by real time PCR analysis. In addition, shRNA-mediated knockdown of macrophage NaV1.5 inhibited LPS-mediated activation of the transcription factor NFkappaB and stimulation-induced apoptosis. Preliminary experiments suggest that knockdown of NaV1.5 prevents a decrease in cytosolic calcium that is necessary for optimal activation of NFkappaB. These results suggest that a variant of human NaV1.5 may regulate intracellular signaling during macrophage priming.
This work is support by an award from the National Multiple Sclerosis Society (RG-3888) and the National Institutes of Health (K02-NS047457-01).
Mycobacteria induce the inactive form of cyclooxygenase-2 (COX-2) without inducing endoplasmic reticulum (ER) stress responses in local macrophages (Mνll]) (135.29)
Authors: Pantuso Traci , Kogiso Mari , Shinohara Tsutomu , Henriksen Ruth Ann , Dorey C. Kathleen , Shibata Yoshimi 
Published: January 2023

Abstract
In response to pathogens, activated MØ frequently express COX-2, which mediates increased release of prostaglandin E2 (PGE2), regulating host defense and inflammatory responses. We previously demonstrated, however, that i.p. administration of HK- Mycobacterium bovis BCG or M. tuberculosis resulted within 24h in increased COX-2 formation, which was subcellularly dissociated from the nuclear envelope (NE), enzymatically inactive and mediated no PGE2 release in peritoneal MØ. In contrast, when normal peritoneal MØ isolated from mice or RAW264.7 MØ were activated for 24h in vitro by BCG, they expressed increased COX-2, which was subcellularly localized in the NE and mediated increased release of PGE2. To assess whether production of inactive COX-2 is associated with ER stress-dependent signaling, we measured selected ER stress protein levels in peritoneal MØ from C57Bl/6 mice and RAW264.7 MØ that were treated with BCG in vitro or in vivo. Literature indicates that in vivo administration of endotoxin has been shown to up-regulate ER stress responses. We found that ER stress proteins growth arrest and DNA-damage-inducible gene 153, glucose regulated protein 78, and the phosphorylation of eukaryotic initiation factor two were up-regulated in RAW264.7 MØ when stimulated with endotoxin, tunicamycin or thapsigargin. However, no detectable changes in ER stress proteins were found in BCG-treated RAW264.7 MØ, in vitro BCG-treated peritoneal MØ or in vivo BCG-treated peritoneal MØ. Our results indicate that mycobacterial activation of MØ COX-2 expression in vivo or in vitro does not involve ER stress/unfolded protein responses. (Supported by NIH HL71711, DOD DAMD 17-03-1-0004, BCCRP 06BS-04-9615)
TLT2 expression and function are conserved between mouse and human (135.37)
Authors: Thomas Kimberly A , King R Glenn , Justement Louis B 
Published: January 2023

Abstract
Trem-like transcript 2 (TLT2) is an innate immune receptor belonging to the TREM family, but unlike other TREM receptors, it is also expressed on cells of the lymphoid lineage. Murine TLT2 (mTLT2) is expressed on neutrophils, macrophages, and B cells, but not on monocytes or T cells. Within the B cell compartment, mTLT2 expression is highest on MZ and B1 cells, followed by T1/T2 cells, and then follicular B cells. Expression of mTLT2 is upregulated on neutrophils and macrophages, but not B cells, in response to inflammatory stimuli. Ligation of mTLT2 on B cells results in enhanced migration towards various chemokines in vitro. Human TLT2 (hTLT2) and mTLT2 exhibit 60% homology, but little is known regarding hTLT2 expression and function. Therefore, studies were performed to characterize its expression profile and function. Neutrophils, macrophages, and B cells express hTLT2, but not T cells. In contrast to mouse, hTLT2 is expressed on human monocytes at levels comparable to macrophages. A hierarchy of hTLT2 expression is observed in the B cell compartment in which hTLT2 expression is highest on mature, naïve B cells, and decreases upon activation and participation in germinal center reactions. Human B cells and neutrophils exhibit enhanced migration towards chemokines upon hTLT2 ligation in vitro, similar to that observed in mouse. Thus, TLT2 expression patterns and function are largely conserved between human and mouse.