bluuebunny/crossref_metadata_2025 huggingface dataset:
Functional changes in the oral microbiome after use of fluoride and arginine containing dentifrices: a metagenomic and metatranscriptomic study
Authors: Carda-Diéguez Miguel , Moazzez Rebecca , Mira Alex
Published: September 2022

Background

Tooth decay is one of the most prevalent diseases worldwide, and efficient tooth brushing with a fluoride-containing dentifrice is considered fundamental to caries prevention. Fluoride-containing dentifrices have been extensively studied in relation to enamel resistance to demineralization. Arginine (Arg) has also been proposed as a promising prebiotic to promote pH buffering through ammonia production. Here, we present the first metagenomic (DNA sequencing of the whole microbial community) and metatranscriptomic (RNAseq of the same community) analyses of human dental plaque to evaluate the effect of brushing with fluoride (Fl) and a Fl+Arg containing dentifrices on oral microbial composition and activity. Fifty-three patients were enrolled in a longitudinal clinical intervention study with two arms, including 26 caries-active and 27 caries-free adults. After a minimum 1-week washout period, dental plaque samples were collected at this post-washout baseline, 3 months after the use of a 1450-ppm fluoride dentifrice, and after 6 months of using a 1450-ppm fluoride with 1.5% arginine dentifrice.

Results

There was a shift in both the composition and activity of the plaque microbiome after 3 months of brushing with the fluoride-containing toothpaste compared to the samples collected at the 1-week post-washout period, both for caries-active and caries-free sites. Although several caries-associated bacteria were reduced, there was also an increase in several health- and periodontitis-associated bacteria. Over 400 genes changed proportion in the metagenome, and between 180 and 300 genes changed their expression level depending on whether caries-free or caries-active sites were analyzed. The metagenome and metatranscriptome also changed after the subjects brushed with the Fl+Arg dentifrice. There was a further decrease of both caries- and periodontitis-associated organisms. In both caries-free and caries-active sites, a decrease of genes from the arginine biosynthesis pathway was also observed, in addition to an increase in the expression of genes associated with the arginine deiminase pathway, which catabolizes arginine into ammonia, thereby buffering acidic pH. Bacterial richness and diversity were not affected by either of the two treatments in the two arms of the study.

Conclusions

Our data demonstrate that long-term use of both assayed dentifrices changes the bacterial composition and functional profiles of human dental plaque towards a healthier microbial community, both in caries-free and caries-active sites. This observation was especially apparent for the Fl+Arg dentifrice. Thus, we conclude that the preventive benefits of tooth brushing go beyond the physical removal of dental plaque and that the active ingredients formulated within dentifrices have a positive effect not only on enamel chemistry but also on the metabolism of oral microbial populations.
Marine DNA methylation patterns are associated with microbial community composition and inform virus-host dynamics
Authors: Seong Hoon Je , Roux Simon , Hwang Chung Yeon , Sul Woo Jun
Published: September 2022

Background

DNA methylation in prokaryotes is involved in many different cellular processes including cell cycle regulation and defense against viruses. To date, most prokaryotic methylation systems have been studied in culturable microorganisms, resulting in a limited understanding of DNA methylation from a microbial ecology perspective. Here, we analyze the distribution patterns of several microbial epigenetics marks in the ocean microbiome through genome-centric metagenomics across all domains of life.

Results

We reconstructed 15,056 viral, 252 prokaryotic, 56 giant viral, and 6 eukaryotic metagenome-assembled genomes from northwest Pacific Ocean seawater samples using short- and long-read sequencing approaches. These metagenome-derived genomes mostly represented novel taxa, and recruited a majority of reads. Thanks to single-molecule real-time (SMRT) sequencing technology, base modification could also be detected for these genomes. This showed that DNA methylation can readily be detected across dominant oceanic bacterial, archaeal, and viral populations, and microbial epigenetic changes correlate with population differentiation. Furthermore, our genome-wide epigenetic analysis of Pelagibacter suggests that GANTC, a DNA methyltransferase target motif, is related to the cell cycle and is affected by environmental conditions. Yet, the presence of this motif also partitions the phylogeny of the Pelagibacter phages, possibly hinting at a competitive co-evolutionary history and multiple effects of a single methylation mark.

Conclusions

Overall, this study elucidates that DNA methylation patterns are associated with ecological changes and virus-host dynamics in the ocean microbiome.
Selected commensals educate the intestinal vascular and immune system for immunocompetence
Authors: Romero Rossana , Zarzycka Agnieszka , Preussner Mathieu , Fischer Florence , Hain Torsten , Herrmann Jan-Paul , Roth Katrin , Keber Corinna U. , Suryamohan Kushal , Raifer Hartmann , Luu Maik , Leister Hanna , Bertrams Wilhelm , Klein Matthias , Shams-Eldin Hosam , Jacob Ralf , Mollenkopf Hans-Joachim , Rajalingam Krishnaraj , Visekruna Alexander , Steinhoff Ulrich
Published: September 2022

Background

The intestinal microbiota fundamentally guides the development of a normal intestinal physiology, the education, and functioning of the mucosal immune system. The Citrobacter rodentium-carrier model in germ-free (GF) mice is suitable to study the influence of selected microbes on an otherwise blunted immune response in the absence of intestinal commensals.

Results

Here, we describe that colonization of adult carrier mice with 14 selected commensal microbes (OMM12 + MC2) was sufficient to reestablish the host immune response to enteric pathogens; this conversion was facilitated by maturation and activation of the intestinal blood vessel system and the step- and timewise stimulation of innate and adaptive immunity. While the immature colon of C. rodentium-infected GF mice did not allow sufficient extravasation of neutrophils into the gut lumen, colonization with OMM12 + MC2 commensals initiated the expansion and activation of the visceral vascular system enabling granulocyte transmigration into the gut lumen for effective pathogen elimination.

Conclusions

Consortium modeling revealed that the addition of two facultative anaerobes to the OMM12 community was essential to further progress the intestinal development. Moreover, this study demonstrates the therapeutic value of a defined consortium to promote intestinal maturation and immunity even in adult organisms.
Empowering local research ethics review of antibacterial mass administration research
Authors: Sewankambo Nelson K. , Kutyabami Paul
Published: September 2022

Background

Recent studies using mass drug administration (MDA) of antibiotics to entire communities have focused global attention on the unique ethical challenges of MDA of antibiotics in research and public health interventions. However, there is no specific guidance for Research Ethics Committees (RECs) or Institutional Review Boards (IRBs) to review such trials. We surveyed the literature to identify the unique ethical challenges and to strengthen the competencies of RECs or IRBs in low- and middle-income countries (LMICs) in their ethical reviews of these trials.

Methods

We employed a desk review. We searched PubMed, Web of Science, and Google Scholar, combining terms for “mass drug administration” with terms for “research ethics committees,” “institutional review boards,” and “ethics.” We reviewed citations of search results to retrieve additional articles. Only articles published and indexed in the above databases up to 6 January 2022 in English were included. Abstracts (without full articles), books and articles that had exclusive veterinary and environmental focus were excluded. We synthesized the literature to identify particularly challenging ethical issues relevant to antibacterial MDA trials in LMICs.

Results

The most challenging ethical issues can be categorised into four broad domains: determining the social value of MDA, assessing risks and benefits, engaging all stakeholders meaningfully, and study design-related ethical challenges. These four domains interact and impact each other. Together, they reveal the need for RECs/IRBs to review MDA studies through a broader lens than that of clinical trials per se. From our findings, we propose a framework to guide the RECs and IRBs in LMICs to perform the initial and continuing review of antibiotic MDA trials. We also recommend strengthening the competencies of LMIC RECs or IRBs through ongoing training and collaboration with RECs or IRBs from high-income countries.

Conclusions

REC/IRB review of research using MDA of antibiotics plays a critical role in assuring the ethical conduct of MDA studies. Local RECs/IRBs should be empowered to review MDA studies comprehensively and competently in order to advance scientific knowledge about MDA and promote improved global health.
Pulsed infrared thermographic study of a Chinese Bronze Lei
Authors: Yang Xue , Chen Beichen , Hu Gangbo , Wang Xiangyu , Fang Wei , Zhang Jianan , Tao Ning , Yuan Guangkuo
Published: September 2022

In this paper, pulsed infrared thermography is applied to the study of a mold casting Chinese bronze lei 罍 dated to the late Shang dynasty (c.a.1250–1050 BC), currently housed in the Capital Normal University Museum. Many spacers and a defective area of this ancient bronze are partly covered with repair material. By analyzing thermographic images using a one-layer thermal diffusion model, it is found that the spacers were specifically made for this bronze. The thickness of the repairing material in the defective area is measured using thermal quadrupole modelling in multi-layer materials. This is the first application of this method to the field of cultural heritage conservation. These results provide a deeper understanding of the manufacturing process of ancient Chinese bronzes from the viewpoint of archaeological research. They also help assess the repair status from the conservation viewpoint.
Combining statistics: the role of phonotactics on cross-situational word learning
Authors: Dal Ben Rodrigo , Souza Débora de Hollanda , Hay Jessica F.
Published: September 2022

Language learners can rely on phonological and semantic information to learn novel words. Using a cross-situational word learning paradigm, we explored the role of phonotactic probabilities on word learning in ambiguous contexts. Brazilian-Portuguese speaking adults (N = 30) were exposed to two sets of word-object pairs. Words from one set of labels had slightly higher phonotactic probabilities than words from the other set. By tracking co-occurrences of words and objects, participants were able to learn word-object mappings similarly across both sets. Our findings contrast with studies showing a facilitative effect of phonotactic probability on word learning in non-ambiguous contexts.
Innate lymphoid cells in antitumor immunity
Authors: Salomé Bérengère , Jandus Camilla
Published: September 2022

Innate lymphoid cells (ILCs) are the most recently characterized subset of innate lymphocytes. Based on their specific transcriptional regulation, cytokine secretion pattern and effector functions ILCs mirror the different CD4 T helper cell subsets, with the unique attributes of acting locally in early phases of immune responses, in an antigen-independent manner. In this review, we discuss how ILCs have been implicated in tumorigenesis. Their presence might favor or inhibit tumor growth, depending on the cytokines released and the specific tumor microenvironment. As our understanding of ILCs’ contribution to antitumor responses advances, clinical options to target ILCs in antitumor therapies are also emerging.
Evaluation of the expression of NADPH oxidase components during maturation of HL-60 cells to neutrophil lineage
Authors: Hua Jian , Hasebe Takeshi , Someya Akimasa , Nakamura Shinji , Sugimoto Koichi , Nagaoka Isao
Published: September 2022

To understand the expression of NADPH oxidase components during neutrophil maturation, we examined the expression of mRNAs and proteins for NADPH oxidase components, and the superoxide-producing activity using HL-60 cells incubated with dimethyl sulfoxide (DMSO). Northern blot and Western blot analyses revealed that gp91phox, p67phox, and p47phox were expressed after myelocyte stages, whereas p22phox, p40phox, and rac-2 were expressed from the promyelocyte stage. Furthermore, immunocytochemical staining of DMSO-induced HL-60 cells indicated that gp91phox, p67phox, and p47phox were detected only after myelocyte stages (myelocytes, metamyelocytes, band cells, and segmented cells), whereas p22phox, p40phox, and rac-2 were detected from the promyelocyte stage. In addition, nitro blue tetrazolium (NBT) assay showed that superoxide could be produced after myelocyte stages but not produced before promyelocyte stages. Moreover, almost the same results as those with DMSO-induced HL-60 cells were obtained using human bone-marrow cells by immunocytochemical staining and NBT assay, except that p22phox was detected by immunocytochemical staining after myelocyte stages in bone-marrow cells. Together, these observations indicate that all the components for NADPH oxidase are expressed, and the superoxide-producing activity is obtained after myelocyte stages during neutrophil maturation.
Lipopolysaccharide-triggered desensitization of TNF-α mRNA expression involves lack of phosphorylation of IκBα in a murine macrophage-like cell line, P388D1
Authors: Fujihara Mitsuhiro , Wakamoto Shinobu , Ito Takatoshi , Muroi Masashi , Suzuki Tsuneo , Ikeda Hisami , Ikebuchi Kenji
Published: September 2022

Activation of nuclear factor κB (NF-κB) is thought to be required for cytokine production by lipopolysaccharide (LPS)-responsive cells. Here, we investigated the contribution of NF-κB in preventing LPS-induced transcription of the tumor necrosis factor α (TNF-α) gene in a murine macrophage cell line, P388D1, when tolerance was induced in the cells with a short exposure to a higher dose of LPS. Electrophoretic mobility shift assays with the κB elements of the murine TNF-α promoter and enhancer revealed that nuclear mobilization of heterodimers of p65/p50, c-rel/p50 and p65/c-rel, and homodimers of p65 was markedly reduced in LPS-tolerant cells, whereas that of p50 homodimers was only slightly increased. Western blot analysis showed that the phosphorylation of Ser32 on IκBα and its transient degradation did not occur in LPS-tolerant cells. These results thus suggest that desensitization of TNF-α gene expression in this LPS-tolerant state is closely associated with down-regulation of transactivating NF-κB and may involve a defect in the LPS-induced IκBα kinase pathway.
Kinins and kinin receptors: importance for the activation of leukocytes
Authors: Böckmann Sabine , Paegelow Inge
Published: September 2022

In this article, we analyzed the role of kinins and kinin receptors with respect to the activation of leukocytes. In these cells, the biological effects of kinin peptides are mediated by kinin receptor subtypes B1, B2, or both, depending on species and cell type. In contrast to the other leukocytes, neutrophils contain the complete system for the synthesis and release of bioactive kinins. Consequently, very high concentrations of these peptides can be reached in the close neighborhood of the kinin receptors, in particular at the site of inflammation. Kinins are responsible for many effects in leukocytes including the release of other inflammatory mediators, such as cytokines, prostaglandins, leukotrienes, and reactive oxygen species. Obviously, the potency of kinins to stimulate leukocytes is dependent on the differentiation and especially on the activation stage of these cells. An upregulation of kinin receptors on neutrophils and macrophages appears to be involved in increasing the sensitivity of these cells to kinins at the site of inflammation.
Modulation of nitric oxide-evoked apoptosis by the p53-downstream target p21WAF1/CIP1
Authors: Yang Fan , von Knethen Andreas , Brüne Bernhard
Published: September 2022

When produced in excess, the inflammatory mediator nitric oxide (NO) attenuates cell-cycle progression at the G1 phase in tight correlation with p21WAF1/CIP1 expression, provokes accumulation of the tumor suppressor p53, and initiates apoptosis/necrosis as judged on cell accumulation in the sub-G1 phase. To verify the role of p21WAF1/CIP1 in modulating cell-cycle arrest vs. apoptosis, we transfected stably antisense p21WAF1/CIP1-encoding plasmids. Following NO exposure, accumulation of p21WAF1/CIP1, but not p53, was largely attenuated in antisense p21WAF1/CIP1 transfectants. Moreover, the G1 cell-cycle arrest was abrogated, and cells were sensitized toward apoptosis compared with parent macrophages. In contrast, antisense elimination of p53 attenuated p53 as well as p21WAF1/CIP1 expression, abolished the G1 cell-cycle arrest, and prevented apoptosis. We conclude that p21WAF1/CIP1 is a downstream target of p53 in macrophages that modulate the sensitivity toward the immune-modulator NO.
The role of architectural transcription factors in cytokine gene transcription
Authors: Shannon M F , Coles L S , Attema J , Diamond P
Published: September 2022

The strict control of cytokine gene transcription is required for the correct regulation of an immune response. Cytokine gene transcription is generally inducible and can also be cell-type specific. Promoter and enhancer regions that control the expression of these genes assemble complex arrays of transcription factors known as enhanceosomes. One important aspect of the organization of these multi-protein complexes is the presence of proteins known as architectural transcription factors. Architectural proteins influence structural aspects of enhanceosomes through protein:DNA as well as protein:protein interactions. The high mobility group I(Y) and the cold shock domain families of architectural proteins have been shown to play roles in cytokine gene transcription and will be discussed here. These families of proteins interact with specific structural features of DNA, modulate transcription factor binding to DNA, and interact directly with other transcription factors. The mechanisms by which they affect inducible cytokine gene transcription will be discussed.
Molecular motors involved in T cell receptor clusterings
Authors: Krawczyk Connie , Penninger Josef M
Published: September 2022

Engagement of antigen receptors on T and B cells triggers reorganization of the cytoskeleton and ordered clustering of cell surface receptors. These receptor clusters constitute spatially organized signaling machines and form the immune synapse with antigen-presenting cells. Formation of supramolecular activation clusters appear to be essential to induce functional lymphocyte responses and have been implicated as molecular mechanisms of costimulation. The Vav1-Rho-GTPase-WASP pathway constitutes a molecular motor that relays antigen receptor stimulation to changes in the cytoskeleton and receptor clustering.
Eosinophil recruitment into sites of delayed-type hypersensitivity reactions in mice
Authors: Teixeira Mauro M , Talvani André , Tafuri Wagner L , Lukacs Nicholas W , Hellewell Paul G
Published: September 2022

The selective accumulation of eosinophils in tissue is a characteristic feature of allergic diseases where there is a predominance of lymphocytes expressing a Th2 phenotype. In an attempt to define factors determining specific eosinophil accumulation in vivo, we have used a radiolabeled technique to assess the occurrence and the mechanisms underlying 111In-eosinophil recruitment into Th1- and Th2-predominant, delayed-type hypersensitivity (DTH) reactions. Eosinophils were purified from the blood of IL-5 transgenic mice, labeled with 111In and injected into nontransgenic CBA/Ca mice. Th1- and Th2-predominant, DTH reactions were induced in mice by immunization with methylated bovine serum albumin (MBSA) in Freund's complete adjuvant or with Schistosoma mansoni eggs, respectively. In these animals, 111In-eosinophils were recruited in skin sites in an antigen-, time-, and concentration-dependent manner. Depletion of CD4+ lymphocytes abrogated 111In-eosinophil recruitment in both reactions. Pretreatment of animals with anti-IFN-γ mAb abrogated111In-eosinophil recruitment in MBSA-immunized and -challenged animals, whereas anti-IL-4 inhibited111In-eosinophil recruitment in both models. Local pretreatment with an anti-eotaxin polyclonal antibody inhibited the MBSA and SEA reactions by 51% and 39%, respectively. These results demonstrate that, although eosinophilia is not a feature of Th1-predominant, DTH reactions, these reactions produce the necessary chemoattractants and express the necessary cell adhesion molecules for eosinophil migration. The control of the circulating levels of eosinophils appears to be a most important strategy in determining tissue eosinophilia.
Genetic background of attenuatedSalmonella typhimuriumhas profound influence on infection and cytokine patterns in human dendritic cells
Authors: Dreher Donatus , Kok Menno , Cochand Laurence , Gitahi Kiama Stephen , Gehr Peter , Pechère Jean-Claude , Nicod Laurent Pierre
Published: September 2022

Salmonella typhimurium (ST) can cause infection inman, and attenuated strains are under consideration as live vaccinevectors. However, little is known about the interaction of ST withhuman dendritic cells (DC). Here, we compared the consequences ofexposure of human, monocyte-derived DC with different attenuatedstrains of ST. Infection was observed with all four strains tested(wild type, PhoP−, PhoPc, and AroA), but the PhoPc strainwas by far the most efficient. Intracellular persistence of wild typeand PhoP− was longer than that of PhoPc and AroA, both ofwhich were largely eliminated within 24 h. Most DC survivedinfection by the attenuated strains, although apoptosis was observed ina fraction of the exposed cells. All strains induced DC maturation,independent from the extent of infection. Although all strainsstimulated secretion of TNF-α and IL-12 strongly, PhoPc inducedsignificantly less IL-10 than the other three strains and as much as 10times less IL-10 than heat-killed PhoPc, suggesting that this mutantsuppressed the secretion of IL-10 by the DC. These data indicate thatinfectivity, bacterial elimination, and cytokine secretion in human DCare controlled by the genetic background of ST.
Superantigen antagonist blocks Th1 cytokine gene induction and lethal shock
Authors: Arad Gila , Hillman Dalia , Levy Revital , Kaempfer Raymond
Published: September 2022

Bacterial superantigens trigger an excessive, Th1-cytokine response leading to toxic shock. We designed a peptide antagonist that inhibits SEB-induced expression of human genes for IL-2, IFN-γ, and TNF-β, cytokines that mediate shock. The peptide antagonist shows homology to a β-strand-hinge-α-helix domain that is conserved structurally in superantigens produced by Staphylococcus aureus andStreptococcus pyogenes yet remote from known binding sites for the major histocompatibility class II molecule and T-cell receptor. For Th1-cell activation, superantigens depend on this domain. The peptide protected mice against lethal challenge with SEB or SEA. Moreover, it rescued mice undergoing toxic shock. Surviving mice rapidly developed broad-spectrum, protective immunity, which rendered them resistant to further lethal challenges with different staphylococcal and streptococcal superantigens. Thus, the lethal effect of superantigens, mediated by Th1 cytokines, can be blocked with a peptide antagonist that inhibits their action at the top of the toxicity cascade, before activation of T cells takes place.
Chemokine receptors in human basophils: inducible expression of functional CXCR4
Authors: Iikura Motoyasu , Miyamasu Misato , Yamaguchi Masao , Kawasaki Hiroshi , Matsushima Kouji , Kitaura Motoji , Morita Yutaka , Yoshie Osamu , Yamamoto Kazuhiko , Hirai Koichi
Published: September 2022

We examined the expression profile of chemokine receptors in humanbasophils and their regulation by cytokines. Basophils expressedtranscripts of CC chemokine receptors (CCR)1, CCR2, CCR3, and CCR5 andCXC chemokine receptors (CXCR)1, CXCR2, and CXCR4. In contrast to theother receptors, surface-CXCR4 expression was not detected in fresh-and whole-blood basophils, but it became apparent gradually duringincubation. Among 16 chemokines tested, eotaxin induced the most potentbasophil migration. SDF-1 also induced a strong, migratory responsecomparable with that induced by eotaxin in 24-h, cultured basophils,but it failed to induce degranulation. IL-3 abrogated CXCR4 expressioncompletely, and it only down-regulated CCR2 and CCR3 expressionslightly. IL-5, GM-CSF, and IL-4 also down-regulated CXCR4 expression.Thus, expression of CXCR4 was the most strongly affected by cytokines,and this may represent an alternative mechanism for control ofcell-specific, biological responses to SDF-1.
A cytokine-to-chemokine axis between T lymphocytes and keratinocytes can favor Th1 cell accumulation in chronic inflammatory skin diseases
Authors: Albanesi Cristina , Scarponi Claudia , Sebastiani Silvia , Cavani Andrea , Federici Monica , Sozzani Silvano , Girolomoni Giampiero
Published: September 2022

The recruitment of T cells into the skin is regulated by chemokines released by resident cells. In this study, we found that normal human keratinocytes activated with Th1-derived supernatant (sup) expressed early (6–12 h) IP-10/CXCL10, MCP-1/CCL2, IL-8/CXCL8, and I-309/CCL1 mRNAs and with slower kinetics (24–96 h), RANTES/CCL5 and MDC/CCL22 mRNAs. Upon stimulation with the Th1 sup, keratinocytes secreted high levels of RANTES, IP-10, MCP-1, and IL-8 and moderate levels of I-309 and MDC. Although much less efficiently, Th2 sup could also induce keratinocyte expression of IL-8, IP-10, RANTES, and MCP-1 but not of I-309 and MDC. TARC/CCL17 was not significantly induced by any stimuli. Sup from keratinocytes activated with Th1-derived cytokines elicited a strong migratory response of Th1 cells and a limited migration of Th2 cells, whereas sup from Th2-activated keratinocytes promoted a moderate migration of Th1 and Th2 lymphocytes. Thus, keratinocytes appear considerably more sensitive to Th1- than to Th2-derived lymphokines in terms of chemokine release and can support the preferential accumulation of Th1 lymphocytes in the skin.
Uptake of apoptotic leukocytes by synovial lining macrophages inhibits immune complex–mediated arthritis
Authors: van Lent P L E M , Licht R , Dijkman H , Holthuysen A E M , Berden J H M , van den Berg W B
Published: September 2022

Previously we have shown that synovial lining macrophages (SLMs) determine the onset of experimental immune complex–mediated arthritis (ICA). During joint inflammation, many leukocytes undergo apoptosis, and removal of leukocytes by SLMs may regulate resolution of inflammation. In this study we investigated binding and uptake of apoptotic leukocytes by SLMs and its impact on the onset of murine experimental arthritis. We used an in vitro model to evaluate phagocytosis of apoptotic cells on chemotaxis. Phagocytosis of apoptotic thymocytes resulted in a significant decrease (58%) of chemotactic activity for polymorphonuclear neutrophils (PMNs). If apoptotic cells were injected directly into a normal murine knee joint, SLMs resulted in a prominent uptake of cells. After ICA induction, electron micrographs showed that apoptotic leukocytes were evidently present in SLMs on days 1 and 2. Injection of apoptotic leukocytes into the knee joint 1 h before induction of ICA significantly inhibited PMN infiltration into the knee joint at 24 h (61% decrease). This study indicates that uptake of apoptotic leukocytes by SLM reduces chemotactic activity and inhibits the onset of experimental arthritis. These findings indicate an important mechanism in the resolution of joint inflammation.
Laminin binding to the calreticulin fragment vasostatin regulates endothelial cell function
Authors: Yao Lei , Pike Sandra E , Tosato Giovanna
Published: September 2022

Vasostatin, the 1–180 amino acids NH2 domain of calreticulin, inhibits endothelial cell proliferation, angiogenesis, and tumor growth, but the mechanisms underlying these effects areunclear. We show that endothelial cells express the extracellularmatrix protein laminin, including chains α5 and γ1 and thatvasostatin specifically binds to laminin. When added to endothelialcell cultures, vasostatin specifically inhibits endothelial cellattachment to laminin and by this mechanism, can reduce subsequentendothelial cell growth induced by basic fibroblast growth factor. Asan angiogenesis inhibitor that specifically disrupts endothelial cellattachment to components of the extracellular matrix, vasostatin has aunique potential as a cancer therapeutic.
Molecular mechanisms of glucocorticoid antiproliferative effects: antagonism of transcription factor activity by glucocorticoid receptor
Authors: Almawi Wassim Y , Melemedjian Ohannes K
Published: September 2022

Glucocorticoids (GCs) exert their anti-inflammatory andimmunosuppressive effects by inhibiting the expression of cytokines andadhesion molecules. The molecular basis of GC action lies in theircapacity to diffuse through the cell membrane and bind their cytosolicGC receptor (GR), which subsequently undergoes nuclear translocationand modulates transcriptional activation through association withpromoter elements, GC response elements (GRE). GR also antagonized theactivity of transcription factors, including NF-κB, NF-AT, and AP-1,through direct and indirect mechanisms. GCs induced the genetranscription and protein synthesis of the NF-κB inhibitor, IκB. Activated GR antagonized transcription factor activity throughprotein:protein interaction. This involved complexing with andinhibition of transcription factor binding to DNA (simple model),association with factor bound at its DNA site (compositemodel), and/or through interaction of GRE-bound GR withDNA-bound transcription factor (transmodulation model). Finally, GRcompeted with transcription factors for nuclear coactivators(competition model), including CBP and p300. Remarkably, GR did notaffect the assembly of the preinitiation complex but acted proximallyin inhibiting transcription factor activity and thus transcriptionalinitiation.
Macrophages from IL-12p40-deficient mice have a bias toward the M2 activation profile
Authors: Bastos Karina R B , Alvarez José M , Marinho Cláudio R F , Rizzo Luiz V , D'Império Lima Maria Regina
Published: September 2022

Recent studies have provided evidence that macrophages from Th1-prone mouse strains respond with an M1 profile, and macrophages from Th2-prone mouse strains respond with an M2 profile, characterized by the dominant production of NO or TGF-β1, respectively. We have shown that peritoneal macrophages from IL-12p40 gene knockout mice have a bias toward the M2 profile, spontaneously secreting large amounts of TGF-β1 and responding to rIFN-γ with weak NO production. Moreover, IL-12p40KO macrophages are more permissive to Trypanosoma cruzi replication than their wild-type littermate cells. Prolonged incubation with rIL-12 fails to reverse the M2 polarization of IL-12p40KO macrophages. However, TGF-β1 is directly implicated in sustaining the M2 profile because its inhibition increases NO release from IL-12p40KO macrophages. IFN-γ deficiency is apparently not the reason for TGF-β1 up-regulation, because rIFN-γKO macrophages produce normal amounts of this cytokine. These findings raise the possibility that IL-12 has a central role in driving macrophage polarization, regulating their intrinsic ability to respond against intracellular parasites.
Glutathione redox regulates lipopolysaccharide-induced IL-12 production through p38 mitogen-activated protein kinase activation in human monocytes: role of glutathione redox in IFN-γ priming of IL-12 production
Authors: Utsugi Mitsuyoshi , Dobashi Kunio , Koga Yasuhiko , Shimizu Yasuo , Ishizuka Tamotsu , Iizuka Kunihiko , Hamuro Junji , Nakazawa Tsugio , Mori Masatomo
Published: September 2022

We examined whether changes in intracellular reduced (GSH) or oxidized (GSSG) glutathione of human monocytes regulate lipopolysaccharide (LPS)-induced IL-12 production and defined the molecular mechanism that underlies glutathione redox regulation. Monocytes exposed to glutathione reduced form ethyl ester (GSH-OEt) or maleic acid diethyl ester (DEM) increased or decreased the intracellular GSH/GSSG ratio, respectively. LPS-induced IL-12 production and p38 mitogen-activated protein (MAP) kinase activation were enhanced by GSH-OEt but suppressed by DEM. Selective p38 inhibitors showed that p38 promoted GSH-OEt-enhanced IL-12 production. Furthermore, IFN-γ priming increased the GSH/GSSG ratio and enhanced IL-12 production through p38, and DEM negated the priming effect of IFN-γ on p38 activation and IL-12 production as well as on the GSH/GSSG ratio. These findings reveal that glutathione redox regulates LPS-induced IL-12 production from monocytes through p38 MAP kinase activation and that the priming effect of IFN-γ on IL-12 production is partly a result of the glutathione redox balance.
Occupancy of adenosine A2a receptors promotes fMLP-induced cyclic AMP accumulation in human neutrophils: impact on phospholipase D activity and recruitment of small GTPases to membranes
Authors: Thibault Nathalie , Burelout Chantal , Harbour Danielle , Borgeat Pierre , Naccache Paul H , Bourgoin Sylvain G
Published: September 2022

The aim of this study was to assess in human neutrophils theimplication of an adenosine 3′,5′-cyclic monophosphate (cAMP)-dependentpathway in the inhibitory effects of A2a receptor engagement. We foundthat Ro20-1724, a cAMP phosphodiesterase inhibitor, in the presence ofadenosine deaminase (ADA) or A2a receptor antagonists renderedtransient the fMLP-induced sustained increases in cAMP levels. The roleof A2a receptor stimulation was demonstrated by the ability of the A2areceptor agonist, CGS21680, to prevent ADA-mediated reduction of thepersistent cAMP elevation induced by fMLP. Persistent cAMP elevationcorrelated with inhibition of fMLP-induced PLD activation andrecruitment of Arf, RhoA, and PKC to membranes. The suppressive effectof CGS21680 or isoproterenol, a β-adrenergic receptor agonist, wasincreased by Ro20-1724 or by the adenylyl cyclase activator, forskolin, and reversed, at least in part, by the inhibitor of adenylyl cyclase,2′,5′-dideoxyadenosine. The activator of protein kinase A (PKA),Sp-cAMP inhibited fMLP-induced PLD activation and translocation of Arfand RhoA to membranes. In contrast, the suppression by A2a receptorstimulation of fMLP-induced PLD activation and cofactor recruitment wasantagonized by PKA inhibitors, Rp-cAMP and H89. In conclusion, A2areceptor occupancy by extracellular adenosine inhibits fMLP-inducedneutrophil activation via cAMP and PKA-regulated events.
Distinct fates of monocytes and T cells directly activated byPseudomonas aeruginosaexoenzyme S
Authors: Epelman Slava , Neely Graham G , Ma Ling Ling , Gjomarkaj Mark , Pace Elisabetta , Melis Mario , Woods Donald E , Mody Christopher H
Published: September 2022

Gram-negative infections can cause overwhelming inflammatory responses. Although factors other than LPS are clearly involved, these factors and their mechanisms of action have been poorly defined. During studies of LPS-independent inflammatory responses of the gram-negative pathogen Pseudomonas aeruginosa, an important virulence factor (exoenzyme S) was shown to be a potent mitogen for T cells. The current work demonstrates that exoenzyme S selectively induced transcription and secretion of biologically active cytokines and chemokines (chemotactic for neutrophils and T cells) from monocytes. Exoenzyme S stimulated highly purified monocytes independent of T cells. In addition, exoenzyme S stimulated T cells directly; neither T-cell activation (CD69) nor apoptosis (hypodiploidy) required the presence of monocytes. However, T-cell activation was enhanced via a noncontact-dependent mechanism as a result of the secretion of TNF-α and IL-6. This study identifies a unique property of a gram-negative-derived microbial product capable of activating multiple cell types and suggests a mechanism by which exoenzyme S contributes to the immunopathogenesis of cystic fibrosis and sepsis in patients infected with P. aeruginosa.
IFN-α2a induces IP-10/CXCL10 and MIG/CXCL9 production in monocyte-derived dendritic cells and enhances their capacity to attract and stimulate CD8+ effector T cells
Authors: Padovan Elisabetta , Spagnoli Giulio C , Ferrantini Maria , Heberer Michael
Published: September 2022

Type I IFNs are immunomodulatory factors that possibly influence the properties of tissue-resident dendritic cells. Here, we have investigated the capacity of IFN-α2a to enhance DC chemoattractive and stimulatory capacity toward CD8+ T lymphocytes. Phenotypically, IFN-α2a-treated DC (IFN-DC) showed an increased expression of costimulatory and antigen-presenting molecules, maintained even after withdrawal of the cytokine. IFN-α2a enhanced DC stimulatory capacity toward CD8+ T cells, as assessed by increased MLR responses and induction of MART-126–35-specific CTLs in vitro. No functional CCR7 chemokine receptor could be induced. Instead, high amounts of IP-10/CXCL10 and MIG/CXCL9 chemokines were produced. Freshly isolated CD8+RO+ cells and PHA-activated CD8+ T cells migrated efficiently in response to IFN-DC-conditioned medium, and the migration could be inhibited by neutralizing the CXCR3 receptor on responder cells. These results suggest that type I IFNs could enhance the elicitation of class I-restricted effector functions in vivo in the periphery by modulating DC chemoattractive properties.
Oxidized low-density and high-density lipoproteins regulate the production of matrix metalloproteinase-1 and -9 by activated monocytes
Authors: Ardans Jeanette A , Economou Antaeus P , Martinson James M , Zhou Min , Wahl Larry M
Published: September 2022

Monocytes/macrophages are prominent in atherosclerotic plaques where the vascular remodeling and plaque rupture may be influenced by the lipids and cytokines at these sites. Therefore, we evaluated the effects of factors found within the vascular wall, such as cytokines, oxidized low-density lipoprotein (ox-LDL), low-density lipoprotein (LDL), and high-density lipoprotein (HDL), on monocyte-derived matrix metalloproteinase-1 (MMP-1) and -9 (MMP-9) and tissue inhibitor of metalloproteinases-1 (TIMP-1). ox-LDL, LDL, and HDL alone had no effect on MMP-1, MMP-9, or TIMP-1 production. However, in the presence of tumor necrosis factor (TNF)-α and GM-CSF, ox-LDL enhanced MMP-1 significantly by two- to threefold, increased MMP-9 slightly, and had no effect on TIMP-1 production. In contrast, HDL suppressed the induction of MMP-1 by TNF-α and GM-CSF as well as the ox-LDL-mediated increase in MMP-1 production. The enhancement of MMP-1 production by ox-LDL occurred through, in part, a prostaglandin E2 (PGE2)-dependent pathway as indomethacin suppressed and PGE2 restored MMP-1 production. This conclusion was supported further by ox-LDL-mediated increases in PGE2 and cyclooxygenase-2 (COX-2) production. These data suggest that the interaction of primary monocytes with ox-LDL and proinflammatory cytokines may contribute to vascular remodeling and plaque rupture.
Rapid static adhesion of human naïve neutrophil to naïve xenoendothelium under physiologic flow is independent of Galα1,3-gal structures
Authors: Sheikh Sajila , Parhar Ranjit , Al-Mohanna Futwan
Published: September 2022

Adhesion interactions under flow have long been known to depend on applied wall shear stress. We investigated the ability of human naïve neutrophils to adhere to xenogeneic endothelial cells under static and flow conditions. We demonstrate that human naïve neutrophils bind to xenogeneic endothelial cells under flow conditions. This binding is dependent on the applied stress and is independent of Galα1,3-gal structures, ICAM-1, or its counter ligands LFA-1α and Mac-1. The binding was rapid and is characterized by stationary attachment with no obvious rolling or change in morphology. This binding leads to a transient increase in intracellular-free calcium levels in xenogeneic but not allogeneic-endothelial cells with occasional oscillations that persist long after the initial contact between the two cell types. Previous activation of xenoendothelium by autologous serum or human TNF-α augments binding of human naïve neutrophils to the endothelial cells. Our data suggest novel interaction sites between the xenogeneic endothelial cells and human naïve neutrophils.
Pulmonary eosinophilia in mice devoid of interleukin-5
Authors: Domachowske Joseph B , Bonville Cynthia A , Easton Andrew J , Rosenberg Helene F
Published: September 2022

The biology of the eosinophilic leukocyte—development, recruitment, and prolonged existence in somatic tissues—has been linked almost invariably to the actions of the “eosinophil” cytokine, interleukin-5 (IL-5). Here we demonstrate that pulmonary eosinophilia can occur in the absence of IL-5, as morphologically normal eosinophils are recruited to the lungs of virus-infected IL-5 −/− mice with kinetics and sequelae that are indistinguishable from those of their IL-5 +/+ counterparts. We conclude that pulmonary eosinophilia observed in response to primary paramyxovirus infection occurs via mechanisms that are distinct from those involved in eosinophil responses to allergens and in asthma. Furthermore, the presence of functional eosinophils in IL-5 −/− mice suggests the possibility of developmentally distinct subsets of what has been presumed to be a homogeneous leukocyte population.
Differential morphine tolerance development in the modulation of macrophage cytokine production in mice
Authors: Limiroli Elena , Gaspani Leda , Panerai Alberto E , Sacerdote Paola
Published: September 2022

Morphine has been shown to affect cell-mediated and humoral immune parameters. In this study, we investigated the capacity of in vivo acute and chronic morphine treatment to modulate interleukin (IL)-10 and IL-12 production by LPS and interferon-γ-stimulated resident and thioglycollate-elicited murine peritoneal macrophages and the development of tolerance to these effects. One hour after the acute administration of 5, 10, and 20 mg/Kg morphine, a dose-related decrease of IL-10 and IL-12 levels was present. The pretreatment with naltrexone at doses up to 20 mg/Kg did not prevent the decrease of IL-10 and IL-12 induced by morphine. When the drug was administered chronically, a differential development of tolerance to the immune effects was observed. After 3 days of treatment, the effect of the acute challenge with 20 mg/Kg morphine on IL-12 was lost. In contrast, morphine-induced inhibition of IL-10 disappeared between 10 and 12 days of treatment, in parallel with tolerance to the antinociceptive effect. These results suggest that morphine treatment affects macrophage cytokine production and that tolerance affects this modulation differently.
Decrease in cAMP levels modulates adhesion to fibronectin and immunostimulatory ability of human dendritic cells
Authors: Burzyn Dalia , Jancic Carolina C , Zittermann Sandra , Keller Sarmiento María I , Fainboim Leonardo , Rosenstein Ruth E , Chuluyan H Eduardo
Published: September 2022

The aim of the present study was to analyze the early events elicited by tumor necrosis factor α (TNF-α) on monocyte-derived dendritic cells (moDC) adhesion to fibronectin (FN) and the involvement of cAMP in the signal transduction mechanism. The intracellular concentration of cAMP and moDC adhesion to FN decreased after TNF-α treatment. An inverted dose-dependency for TNF-α effect was observed for adhesion and cAMP levels. The presence of a phosphodiesterase (PDE) inhibitor (IBMX) and cAMP analogs (8Br-cAMP, Db-cAMP) reversed the observed TNF-α effects. The role of cAMP was analyzed further by examining the cAMP levels in nonadhered and adhered, TNF-α-treated moDC. Nonadhered moDC showed lower cAMP levels compared with adhered moDC. Furthermore, nonadhered moDC showed higher IL-12 content and allostimulatory ability compared with adhered moDC. The higher allostimulatory capacity was abolished in the presence of cAMP analogs and a PDE inhibitor. These results suggest that cAMP levels correlate with TNF-α-induced changes of moDC adhesion and allostimulatory capacity.
B cell development and proliferation of mature B cells in human fetal intestine
Authors: Golby Sarah , Hackett Maggie , Boursier Laurent , Dunn-Walters Deborah , Thiagamoorthy Sivashankari , Spencer Jo
Published: September 2022

B cells are present in human fetal intestine from approximately 14 weeks of gestation. Here we show that this population includes mature, dividing B cells. These are large cells with dendritic processes, resembling human thymic B cells. In addition, we observed IgM+, light chain−, and CD20− cells and local expression of V pre-B, demonstrating that the human fetal intestine is a site of B cell development. Ig VHDJH gene sequencing can confirm clonal identity of B cells. Identification of the same IgVH4–34 sequence in serial sections in two fetuses confirmed local accumulation of related cells in each case. IgVH4–34 was also amplified from an additional two samples, and the D and J repertoire compared with a unique database of unselected VH4–34 genes from postnatal gut. Distinguishing characteristics of Ig λ genes in postnatal gut were also studied in the fetus. According to these parameters, fetal and postnatal B cells are unrelated.
Regulation of mediator secretion in human basophils by p38 mitogen-activated protein kinase: phosphorylation is sensitive to the effects of phosphatidylinositol 3-kinase inhibitors and calcium mobilization
Authors: Gibbs Bernhard F , Plath Katharina E S , Wolff Helmut H , Grabbe Jürgen
Published: September 2022

Although human basophils modulate allergic diseases by secreting histamine, leukotriene C4, interleukin (IL)-4, and IL-13, the intermediary signals controlling the release of these mediators are poorly understood. Here, we show that p38 mitogen-activated protein kinase (MAPK) crucially affects basophil activation following stimulation with various secretagogues. Phosphorylation of p38 MAPK occurred within 5 min following anti-immunoglobulin (Ig)E stimulation, but was more rapidly activated in basophils stimulated with formyl-Met-Leu-Phe or A23187. Additionally, activation of p38 MAPK to the above stimuli was dependent on extracellular influx and intracellular mobilization of calcium. SB 203580, a specific p38 MAPK inhibitor, blocked anti-IgE-induced secretion of all basophil mediators and reduced not only p38 MAPK, but also extracellular signal-regulated kinases 1 and 2 activity, whereas the MAPK antagonist, PD 098059, did not affect p38 MAPK. IgE-dependent activation of p38 MAPK and MKK3/6 was affected by LY 294002 and wortmannin, suggesting that these kinases are targets for phosphatidylinositol 3 kinase (PI 3-K). We conclude that p38 MAPK is a pivotal regulator of basophil function downstream of PI 3-K activation and calcium mobilization.