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At least 73 records · Page 4Linked to original sources
PubMed1992

Epidermal compromise in American cutaneous leishmaniasis.

In American cutaneous leishmaniasis (ACL), Leishmania parasites enter the epidermis of the host via the bite of infected sandflies. Immune responses against the parasite vary from "effective" in localized (LCL) to a state of "selective anergy" in diffuse (DCL) cutaneous leishmaniasis, whereas the intermediate muco-cutaneous form (MCL) is characterized by an exacerbated cell-mediated immunity. We have shown that in LCL epidermis, Langerhans cells (LC) are increased, HLA-DR is universally expressed and intercellular adhesion molecule-1 (ICAM-1) immunoreactivity is distributed in patches. In addition, mRNA for IL-1 beta, IL-8, TNF alpha, TNF beta, and INF gamma may be detected in epidermal sheets by reverse transcriptase followed by polymerase chain reaction (RT-PCR). In contrast, DCL epidermis shows fewer LC than LCL epidermis, and expression of ICAM-1, HLA-DR, and IL-1 beta mRNA cannot be detected. MCL lesions show a mucosal epithelium lacking LC, but ICAM-1 is universally expressed. The clinical manifestations of ACL can be reproduced experimentally in different strains of inbred mice. In healthy mice, we have shown a positive correlation between LC and dendritic epidermal T cells (DETC) numbers. This correlation was not, however, observed in L. mexicana-infected mice, suggesting that infection alters the balance between the two cell types. In addition, agents that modulate LC and DETC cell densities change the development of experimental leishmaniasis. These results suggest that the epidermis is essential in determining the type of immune response that is developed against the Leishmania parasites.

Animals↗
PubMed2026

A Novel piRNA-Mediated Epigenetic Axis: piR-36241 Exacerbates Pulpitis by Silencing the Protective Receptor ADGRG2 in Human Dental Pulp Stem Cells.

BACKGROUND: Pulpitis, a prevalent inflammatory dental disease, primarily results from bacterial infection, yet its epigenetic regulatory mechanisms remain poorly understood. PIWI-interacting RNAs (piRNAs), a class of small non-coding RNAs known to maintain genomic stability, have not been investigated in the context of pulpitis. OBJECTIVE: This study aimed to profile piRNA expression patterns in pulpitis and to elucidate the functional role and underlying mechanism of a specific piRNA, piR-36241 and its target gene ADGRG2 in disease progression. METHODS: piRNA and mRNA sequencing were performed on pulp tissues from patients with irreversible pulpitis and healthy controls. Potential piRNA targets were predicted bioinformatically. The interaction between piR-36241 and the 3'UTR of ADGRG2, an orphan adhesion G protein-coupled receptor (GPCR), was validated using dual-luciferase reporter assay, quantitative Real-Time PCR (qRT-PCR), fluorescence in situ hybridization (FISH), Western blot (WB), hematoxylin-eosin staining (HE), immunohistochemistry (IHC) and enzyme-linked immunosorbent assay (ELISA). Functional analyses were conducted in LPS-stimulated human dental pulp cells (HDPCs) through gain-of-function and rescue experiments. RESULTS: We identified a distinct piRNA expression profile in pulpitis, with 21 piRNAs differentially expressed. piR-36241 was notably upregulated. It directly targeted the 3'UTR of ADGRG2 and suppressed its expression. ADGRG2, hypothesised to exert protective and homeostatic functions, was downregulated in pulpitis tissues and LPS-induced HDPCs. Overexpression of piR-36241 inhibited ADGRG2 expression and promoted the secretion of pro-inflammatory cytokines (IL-6, IL-8). Conversely, knockdown of ADGRG2 similarly enhanced inflammatory responses. Rescue experiments demonstrated that piR-36241 primarily regulates inflammation through ADGRG2 silencing. CONCLUSION: Our study reveals a novel pathogenic axis in pulpitis whereby upregulation of piR-36241 exacerbates inflammatory progression by repressing the protective receptor ADGRG2. These findings provide the first evidence of piRNA-mediated epigenetic regulation in pulpitis and highlight the piR-36241/ADGRG2 pathway as a potential therapeutic target for preserving pulp vitality.

Humans↗
PubMed1992

Mononuclear cells from HIV-infected patients produce factors which enhance functional activity of polymorphonuclear neutrophils from healthy subjects.

The influence of mononuclear cell supernatants (MNCS) from nine healthy donors and 35 HIV-infected patients (17 with lymphoadenopathy syndrome (LAS), 15 with ARC and three with AIDS) on functional activity of polymorphonuclear neutrophils (PMN) from healthy donors was investigated. MNC after short-term cultivation (24 h) produced factors which enhanced chemiluminescence (CL) and chemotaxis of PMN. This augmentation did not depend on stimulation of MNC by mitogens (lipopolysaccharide Escherichia coli (LPS) and concanavalin A (Con A)) or on activation of PMN by FMLP. After 48 h of cultivation only MNC stimulated by LPS produced these factors. MNCS from HIV-infected patients provoked a more pronounced augmentation of PMN CL compared with MNCS from healthy subjects. This enhancement was observed in patients at all stages of infection, but was more pronounced in patients with LAS. MNCS impact on PMN CL was not connected with proliferative activity of MNC but was correlated with the level of CD4 cells. It was shown that removal of adherent cells from MNC fraction resulted in decreased MNCS impact. Treatment of MNCS by antibody to IL-1 beta, IL-8, interferon-alpha (IFN-alpha) and tumour necrosis factor-alpha (TNF-alpha) did not decrease MNCS impact on PMN CL.

AIDS-Related Complex↗
PubMed1992

Human polymorphonuclear leucocytes stimulated by tumour necrosis factor-alpha show increased adherence to extracellular matrix proteins which is mediated via the CD11b/18 complex.

The present study demonstrates that tumour necrosis factor (TNF) and FMLP, but not IL-1 or IL-8, enhanced the adherence of polymorphonuclear neutrophil (PMN) to fibronectin, an extracellular matrix protein. The adherence induced by FMLP was very rapid, within 5 min while the induction of adherence by TNF was much slower, reaching maximum at 60 min. TNF also enhanced an adhesion of PMN to other extracellular matrix proteins, such as laminin, collagen IV and gelatin II, but not to human serum albumin. Anti-CD18 MoAb completely inhibited the binding of TNF-stimulated PMN to fibronectin and partially inhibited the binding to laminin. Further investigation showed that adhesion of TNF-stimulated PMN to fibronectin and laminin was inhibited by anti-CD11b MoAb and to a lesser extent by CD11a MoAb. In contrast to TNF-stimulated PMN the binding of unstimulated PMN to fibronectin and laminin was only inhibited by anti-CD11a MoAb. Anti-CD11c had no effect on PMN adherence. These results suggest that unstimulated PMN adhere to extracellular proteins through the CD11a/18, while TNF-stimulated PMN adhere through the CD11b/18. These results suggest that TNF secreted at the site of inflammation may enhance the interaction of PMN with the extravascular environment through the CD11b/18 complex.

Antigens, CD↗
PubMed1992

Neutrophil chemotactic factors in the respiratory tract of patients with chronic airway diseases or idiopathic pulmonary fibrosis.

This study was designed to clarify the contributions of specific neutrophil chemotactic factors (NCF) in neutrophil accumulation in the human respiratory tract associated with various diseases. The activity and characteristics of the NCF in the bronchoalveolar lavage (BAL) fluid and culture media of alveolar macrophages obtained from normal volunteers, control patients, patients with chronic airway diseases (CAD) and patients with idiopathic pulmonary fibrosis (IPF) were examined. The BAL fluid from normal volunteers contained NCF comparable with the chemotactic factors interleukin-8 (IL-8) and leukotriene B4 (LTB4). Analysis of the biochemical characteristics of NCF released from alveolar macrophages suggests that they are derived from alveolar macrophages. The NCF activities in BAL fluids from patients with CAD and IPF were higher than those in BAL fluids from normal volunteers and control patients. Biochemical analysis demonstrated that several kinds of NCF, including those derived from the complement component C5 and alveolar macrophages, were present in the BAL fluid from patients with CAD and respiratory infections. The especially marked increase of C5-derived NCF indicate their importance in neutrophil accumulation in the respiratory tract of patients with CAD. Alveolar macrophages released different types of NCF after different lengths of culture periods (4 h and 24 h). Alveolar macrophages from patients with IPF released larger amounts of NCF than alveolar macrophages from normal volunteers, indicating the importance of alveolar-macrophage-derived NCF as well as C5-derived NCF in neutrophil accumulation in the respiratory tract of patients with IPF. These results suggest that various types of NCF increase in response to different disease states of the respiratory tract and serve to regulate the accumulation of neutrophils.

Adult↗
PubMed2026

Functional Variant Discovery Identifies a Novel Genetic Link between SPRY2, Wood Smoke, and Asthma.

As a consequence of climate change and land-use policies, there has been a historic rise in wildfire smoke across the United States and the world. Although the deleterious effects of wildfire smoke and associated air pollution on asthma outcomes are established epidemiologically, genetic risks and molecular mechanisms of how wildfire smoke affects asthma are unknown. This knowledge gap hinders the identification of high-risk individuals and the creation of targeted therapies or recommendations to protect these individuals. We identified 52 genetic risk variants that colocalized with genomic responses to woodsmoke particles (WSPs), a model of wildfire particulate matter, and associated with asthma in the GERA (Genetic Epidemiology Research on Adult Health and Aging) cohort. We used additional filters to prioritize variants for direct testing of allele-dependent transcriptional regulatory function in plasmid reporters. We found that the rs3861144 variant (odds ratioasthma, 1.036) changes SPRY2 responses to WSPs in airway epithelial cells, which are involved in IL-8 secretion, ERK (extracellular signal-related kinase) activation, and mechanical scratch repair in cell culture. These findings provide insights into the molecular pathways through which WSPs may influence asthma risk and propose genetic candidates that warrant further study for their potential as clinical tools for asthma.

Asthma↗
PubMed2026

Redox Rewiring in Nicotine-Driven Gastric Carcinogenesis: Uncovering ROS-Dependent Oncogenic Circuits.

SIGNIFICANCE: Nicotine from tobacco products, secondhand smoke, and emerging delivery systems remains a major but underappreciated driver of gastric carcinogenesis (GC). Although reactive oxygen species (ROS) have long been implicated in tumor biology, current models incompletely explain how chronic nicotine selectively reprograms gastric epithelial signaling. This review advances the concept of redox rewiring, whereby nicotine establishes a persistent oxidative state that orchestrates multiple oncogenic programs via spatially compartmentalized NOX signaling. RECENT ADVANCES: We synthesize evidence for a unified model wherein nicotine activates nAChR/β-AR signaling, Ca2+ influx, PKC, and compartmentalized NOX-derived ROS to generate distinct oncogenic outputs. Beyond the established NOX/ROS/NF-κB/MAPK-driven IL-8 and MMP-9 axes, we integrate emerging evidence into three interconnected modules governing EMT/metastasis (ABL1/STAT3/COX-2/periostin), survival/chemoresistance (ERK/GLI1/Bcl-2), and invasion/immune evasion (miR-21/PDCD4). Collectively, these circuits suggest that ROS function not merely as damaging byproducts but as spatially organized signaling mediators dictating tumor behavior. CRITICAL ISSUES: A major challenge is distinguishing established mechanisms from incompletely validated models. The three proposed axes are testable hypotheses requiring experimental validation. Most data derive from in vitro studies with nonphysiologic nicotine concentrations, and artifacts from nonspecific ROS probes are common. Compensatory pathway activation and multi-target effects of natural products remain underexplored. FUTURE DIRECTIONS: We outline a precision-redox oncology roadmap linking pathway-specific biomarkers, mechanistically matched natural products, and biomarker-enriched trials. Priorities include genetic validation of the three axes, time-resolved ROS imaging, and pulsed natural product regimens. By reframing nicotine-driven GC as adaptive redox network remodeling, this review provides a framework for prevention, stratification, and next-generation therapy. Antioxid. Redox Signal. 00, 000-000.

gastric cancer↗
PubMed1992

The 9E3 protein: immunolocalization in vivo and evidence for multiple forms in culture.

The avian gene 9E3/CEF4 belongs to a group of genes whose products are highly conserved and are homologous to inflammatory mediators. These genes, sometimes referred to as the gro family, are also expressed upon wounding or serum-stimulation of quiescent cells, suggesting that they may be important in aspects of growth and/or wound healing. We have used an antibody to the product of the 9E3 gene to show for the first time the distribution in vivo of the protein of one of these genes. The polyclonal antibody was produced against a synthetic peptide, [Cys76], 9E3, (77-103), located at the carboxy end of the molecule. The specificity of the antibody was determined by transfection of the 9E3 cDNA into Cos 7 cells, which do not express this gene. Moreover, despite the high homology between 9E3 and IL-8, the antibody did not crossreact with this molecule. The antibody was used to immuno-precipitate the protein from cultured normal and RSV-transformed chick embryo fibroblasts (CEFs) and to determine its distribution in tissues of newly hatched chicks. The staining was abundant in the cells and extracellular matrix (ECM) of connective tissue and other tissues of mesenchymal origin, such as bone and tendon. Most cells in the granulation tissue of wounds stained, some more intensely than others; the ECM also stained, especially in areas of scar tissue where collagen is abundant. In RSV-induced tumors, the protein was absent except in necrotic areas where a few cells--potentially macrophages--stained. In general, as expected, the protein was present in the cells and tissues that expressed the mRNA, but there were exceptions.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed2025

Tumor microenvironment governs the prognostic landscape of immunotherapy for head and neck squamous cell carcinoma: A computational model-guided analysis.

Immune checkpoint inhibition (ICI) has emerged as a critical treatment strategy for squamous cell carcinoma of the head and neck (HNSCC) that halts the immune escape of the tumor cells. Increasing evidence suggests that the onset, progression, and lack of/no response of HNSCC to ICI are emergent properties arising from the interactions within the tumor microenvironment (TME). Deciphering how the diversity of cellular and molecular interactions leads to distinct HNSCC TME subtypes subsequently governing the ICI response remains largely unexplored. We developed a cellular-molecular model of the HNSCC TME that incorporates multiple cell types, cellular states, and transitions, and molecularly mediated paracrine interactions. Simulation across the selected parameter space of the HNSCC TME network shows that distinct mechanistic balances within the TME give rise to the five clinically observed TME subtypes such as immune/non-fibrotic, immune/fibrotic, fibrotic only and immune/fibrotic desert. We predict that the cancer-associated fibroblast, beyond a critical proliferation rate, drastically worsens the ICI response by hampering the accessibility of the CD8 + killer T cells to the tumor cells. Our analysis reveals that while an Interleukin-2 (IL-2) + ICI combination therapy may improve response in the immune desert scenario, Osteopontin (OPN) and Leukemia Inhibition Factor (LIF) knockout with ICI yields the best response in a fibro-dominated scenario. Further, we predict Interleukin-8 (IL-8), and lactate can serve as crucial biomarkers for ICI-resistant HNSCC phenotypes. Overall, we provide an integrated quantitative framework that explains a wide range of TME-mediated resistance mechanisms for HNSCC and predicts TME subtype-specific targets that can lead to an improved ICI outcome.

Tumor Microenvironment↗
PubMed2025

Trichomonas vaginalis extracellular vesicles activate the NLRP3 inflammasome and TLR3-mediated inflammatory cascades in host cells.

Trichomonas vaginalis (TV) is a flagellated parasite that causes trichomoniasis, the most common non-viral sexually transmitted infection (STI), with over 275 million cases annually. TV has been shown to secrete extracellular vesicles (TV-EVs) to regulate intercellular communication between parasites and host immune response; however, the mechanisms by innate immunity against TV-EVs are largely unknown. Herein, we aim to investigate the molecular mechanisms of inflammation induced by TV-EVs and identify novel proteins modulating the immune response in host cells. Firstly, the morphological characteristics of TV-EVs have been analyzed by transmission electron microscope (TEM) and nanoparticle tracking analysis, revealing that the vesicles are round-shaped bilayer membrane structures with size mostly about 100-120 nm. Additionally, the internalization of TV-EVs by host cells has been validated through immunofluorescence and TEM analysis. The multiplex immunoassay identified that TV-EVs induce the secretion of inflammatory cytokines, including CXCL1, IL-6, IL-8 and MIP-1β in THP-1 macrophages and ectocervical cells (Ect). Mechanistically, TV-EVs induce TLR3 overexpression to activate the NF-κB/NLRP3 pathway in THP-1 macrophages. Additionally, TV-EVs activate the PI3K-mediated NF-κB, p38 MAPK and ERK pathways in Ect. Moreover, TV-EV-induced TLR3 overexpression positively regulates the PI3K and NF-κB pathways, while simultaneously suppressing the p38 MAPK and ERK pathways in Ect. Proteomic analysis identified that TV-EVs upregulate MICB and TRAF3IP2, which are also positively regulated by TLR3 and involved in TV-EV-induced inflammatory cascade. Altogether, this study significantly advances our understanding of the immunomodulatory roles of TV-EVs in host cells, paving the way for future treatment of trichomoniasis and TV-associated STIs.

Humans↗
PubMed2026

Machine learning-integrated multi-omics risk prediction for pulmonary fungal infection in COPD and lung cancer: a transcriptomic and immune profiling study.

BACKGROUND: Chronic obstructive pulmonary disease (COPD) and lung cancer are major risk factors for invasive pulmonary fungal infection (IPFI), carrying an attributable mortality of 30%-80%. Their coexistence further amplifies immunosuppression, while current diagnostic criteria remain inadequate for early risk identification. METHODS: Transcriptomic data from the GEO dataset GSE296912 (scRNA-seq; 12,078 cells from normal and COPD lung tissue) and The Cancer Genome Atlas (TCGA)-lung adenocarcinoma (LUAD) bulk RNA-seq cohort (539 tumor and 59 normal samples) underwent differential expression and cross-omics integration analysis. Five machine learning models were constructed: logistic regression, SVM, random forest, XGBoost, and LASSO. Candidate genes were validated by qRT-PCR in A549 cells and THP-1-derived macrophages stimulated with heat-inactivated Aspergillus fumigatus conidia, a protocol selected to ensure BSL-2 biosafety compliance and isolate PAMP-mediated innate immune signaling. Model performance was evaluated using 5-fold stratified cross-validation with AUC, calibration curves, and decision curve analysis. RESULTS: Single-cell transcriptomic analysis of 12,078 cells identified 14 distinct cell populations, with marked myeloid expansion and immune dysregulation in COPD lung tissue. Cross-omics integration with TCGA-LUAD data identified 1,145 shared genes (79 immune-related), converging on NF-κB, TLR4, and cytokine receptor signaling. The random forest model achieved excellent discriminative performance (5-fold CV AUC = 0.988), with Treg infiltration, TLR4, and MMP9 as the top predictors. qRT-PCR confirmed significant upregulation of all five candidate genes (DEFB4A, S100A8, IL-8, MMP9, and TLR4) in both A549 and THP-1 cells following fungal stimulation. CONCLUSION: This multi-omics machine learning model integrating scRNA-seq and TCGA transcriptomic data demonstrates excellent discriminative performance (AUC = 0.988), with mechanistic convergence of NF-κB, TLR4, and oncogenic signaling pathways identified across shared immune gene signatures. In vitro qRT-PCR validation confirms the biological relevance of five key antifungal immune genes, providing a transcriptomic foundation for future prospective IPFI risk stratification in patients with COPD and lung cancer.

TLR4↗
PubMed2026

Impact of NR4A3 on wound healing in chronic venous ulcers and its association with the PI3K/Akt signaling pathway.

BACKGROUND: To investigate the role of NR4A3 in chronic venous ulcer (VU) wound healing and to explore its potential regulatory mechanism involving the PI3K/Akt pathway. METHODS: Differential expression and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses were performed using the GSE174661 dataset. DEGs were filtered by |log2FC| > 1 and adjusted P < 0.05, with KEGG significance set at P < 0.05. NR4A3 was identified as the core gene. NR4A3 knockdown and overexpression were established in HaCaT cells to evaluate proliferation, migration, and inflammatory cytokines. TNF-&#x3b1; was used to mimic the inflammatory microenvironment. Western blotting assessed phosphorylation of GSK3&#x3b2;, mTOR, PI3K, and Akt. PI3K/Akt agonist 740Y-P and inhibitor LY294002 were used in rescue experiments. RESULTS: Bioinformatic analysis revealed that NR4A3 expression was markedly downregulated in chronic venous ulcer (VU) tissues relative to normal skin and ordinary acute wound tissues. Differentially expressed genes were significantly enriched in the PI3K/Akt signaling pathway. TNF-&#x3b1; stimulation significantly upregulated NR4A3 expression and increased phosphorylation of GSK3&#x3b2; and mTOR in HaCaT cells. In cultured HaCaT keratinocytes, NR4A3 knockdown suppressed cell proliferation and invasion, enhanced cell migration, and elevated the expression and secretion of pro-inflammatory cytokines (IL-6, IL-8, CXCL5), accompanied by reduced phosphorylation of PI3K and Akt. Conversely, NR4A3 overexpression promoted cell proliferation and invasion, restrained migration, and dampened inflammatory responses, while increasing PI3K/Akt phosphorylation. Treatment with the PI3K/Akt agonist 740Y-P partially rescued the impaired proliferation, aberrant migration, and excessive inflammation caused by NR4A3 silencing, whereas PI3K/Akt inhibitor LY294002 aggravated pathway suppression. These findings suggest that NR4A3-associated changes in keratinocyte functions and inflammatory reactions are functionally linked to PI3K/Akt pathway activity, and inflammatory stimulation activates GSK3&#x3b2;/mTOR signaling accompanied by compensatory NR4A3 upregulation. CONCLUSION: These findings suggest that NR4A3 is associated with keratinocyte behavior and inflammatory responses via the PI3K/Akt pathway, potentially affecting chronic VU progression and healing. Reduced NR4A3 may impair wound repair through inflammation and abnormal cell migration, while TNF-&#x3b1; induces compensatory NR4A3 elevation.

NR4A3↗
PubMed1992

Prolongation of survival of human polymorphonuclear neutrophils by granulocyte-macrophage colony-stimulating factor is caused by inhibition of programmed cell death.

In the absence of appropriate stimuli, polymorphonuclear neutrophils (PMN) undergo programmed cell death (PCD), also termed apoptosis. We show that granulocyte-macrophage colony-stimulating factor (GM-CSF), but not the chemotactic factors formyl-methionyl-leucyl-phenylalanine (FMLP), recombinant human (rh) C5a, transforming growth factor (TGF)-beta, and interleukin-8 (IL-8), or other cytokines including IL-3, IL-4, IL-6, and G-CSF, maintains viability of PMN in culture by preventing these cells from undergoing PCD. Prevention from PCD by GM-CSF was associated with induction of RNA and protein synthesis in PMN. Inhibition of RNA and protein synthesis by actinomycin-D and cycloheximide impeded the protection of apoptosis by GM-CSF. Similarly, neutralization of GM-CSF biologic activity by a specific antiserum abrogated GM-CSF-mediated inhibition of PCD.

Apoptosis↗
PubMedDate not supplied

Soluble factors levels in the initial staging of high-grade non-Hodgkin's lymphomas.

Plasma levels of several soluble factors were assayed in 31 untreated patients with high-grade non-Hodgkin's lymphomas (NHL). The results showed statistically significant higher average levels of interleukin-2 (IL-2), interleukin-6 (IL-6), interleukin-8 (IL-8), interleukin-2 receptor (IL-2r) and transferrin receptor (TF-r) in NHL patients compared to controls (p = 0.045, p = 0.047, p = 0.020, p = 0.026 and p = 0.033 respectively). IL-2, IL-2r and TF-r levels were found more elevated in Stages III/IV than in Stages I/II (p = 0.031, p = 0.016 and p = 0.048 respectively), whereas IL-6 concentrations were higher in patients presenting B symptoms (p = 0.011). Significant correlations were found between the erythrocyte sedimentation rate (ESR) and IL-6 (r = 0.681), and between beta 2 microglobulin (B2-m) and IL-2r (r = 0.622).

Adult↗
PubMedDate not supplied

Simultaneous quantitation of cytokine mRNAs in interleukin-1 beta stimulated U373 human astrocytoma cells by a polymerisation chain reaction method involving co-amplification with an internal multi-specific control.

The measurement of cytokine mRNA levels is of fundamental importance in the understanding of diverse pathological states. We present a simplification of a polymerase chain reaction-based technique which permits the simultaneous measurement of up to 20 cytokine mRNAs, together with those of several other cellular products, including beta 2-microglobulin and beta-actin. The technique makes use of internal standards bearing multiple PCR primer sites which are identical to those on the mRNAs to be assayed. Known quantities of the standards are added to the cellular RNA and the mixture is co-reverse transcribed and co-amplified. The simplifications described here are based on the fact that each pair of amplicons accumulates in a constant ratio even in the plateau phase of amplification. As a result, no preliminary experiments to determine the limits of the exponential phase of amplification are necessary; the same number of cycles may be chosen for all the mRNAs to be measured, whatever their level in the mixture might be; pipetting errors are avoided since all calculations are based upon the relative quantities of co-amplified material. Here we illustrate the method through a quantitative study of the expression of cytokine mRNAs in U373 human astrocytoma cells before and after stimulation with IL-1 beta. Quantitation was carried out either by incorporating radioactivity in the amplicons or by fluorescence measurements after propidium iodide staining. Only very low numbers of transcripts for IL-6, IL-8, CSF-1, MCP-1 and either Gro alpha or Gro beta were detectable in unstimulated cells. The levels of these cytokine mRNAs increased dramatically following IL-1 beta stimulation and, in addition, transcription of IL-1 beta, TNF alpha, GM-CSF, G-CSF, Gro gamma and MCP-1, some of which have not previously been detected in U373, was initiated in the stimulated cells. At the same time we found that transcripts for IL-2, IL-3, IL-4, IL-5, IFN gamma, huMlP1 alpha and huMlP1 beta were totally absent in this cell line. These results suggest a potentially important role for astrocytes in the local amplification of inflammatory responses in the brain.

Astrocytes↗
PubMed1992

Cytokine-induced (interleukins-3, -6 and -8 and tumour necrosis factor-beta) activation and deactivation of human neutrophils.

The effect of various cytokines [interleukin-3(IL-3), IL-6, IL-8, tumour necrosis factor-beta (TNF-beta)] on human neutrophils (PMN) was analysed with regard to the generation of leukotrienes and the involvement of guanosine triphosphate (GTP)-binding proteins (G proteins). Incubation of cytochalasin B-pretreated PMN with cytokines alone did not lead to a generation of leukotrienes. However, the cytokines affected the formyl-methionyl-leucyl-phenylalanine-(FMLP)-induced formation of leukotrienes in a time-dependent manner. Preincubation of the cells with the different cytokines for short periods (15 seconds at 37 degrees) enhanced the subsequent FMLP-induced leukotriene generation, whereas preincubation for prolonged times resulted in a reduced formation of leukotrienes. These results correlated with the respective G protein-associated guanosine triphosphatase (GTPase) activities within isolated membrane fractions. The present study indicates a modulation of the FMLP-induced leukotriene formation by diverse cytokines via interaction with the GTP-binding proteins.

Cells, Cultured↗
PubMed1992

Antagonism of lipopolysaccharide-induced priming of human neutrophils by lipid A analogs.

Lipid X, a monosaccharide precursor of the lipid A component of LPS, has been found to antagonize LPS-induced priming of human neutrophils in a manner consistent with competitive inhibition. In this investigation, the inhibition of neutrophil priming by lipid A analogs was found to be specific for LPS-induced priming. Priming of neutrophils by TNF, IL-8, and C5a were all unaffected by increasing concentrations of 3-aza-lipid X-4-phosphate (compound 3), a monosaccharide LPS-antagonist. Unlike lipid X, the pattern of antagonism exhibited by some monosaccharide LPS-antagonists was noncompetitive-like. The relationship between the chemical structure and inhibition pattern was found to be complex and not simply related to the type of acyl linkage at the C-3 position of the glucosamine backbone. Lipid A analogs were found to antagonize calcium ionophore A23187-stimulated leukotriene B4 (LTB4) production from LPS-primed neutrophils in a pattern of inhibition qualitatively similar to that seen with FMLP-stimulated O2- production. Resting and FMLP-stimulated (peak) cytosolic-free calcium levels did not differ significantly between unprimed and LPS-primed neutrophils, (p = 0.67 and p = 0.97, respectively). Furthermore, antagonism of LPS-mediated priming by 3-aza-lipid X-4-phosphate (compound 3) could not be explained by changes in intracellular calcium flux despite marked inhibition of O2- production (p less than 0.0001). Thus, lipid A analogs antagonize only LPS-induced priming and the pattern of inhibition is dependent on the chemical structure. Inhibition of LPS-induced priming by lipid A analogs may involve an early step in the signal transduction pathway common to both O2- and LTB4 generation, but independent of intracellular calcium concentration.

Calcium↗
PubMed1992

[New findings in emergency care and resuscitation in patients at risk for endotoxic shock].

Endotoxin shock is not only the reflexion of Gram-negative focal infection but also the consequence of dysfunction of the intestinal mucous barrier and a decline of the detoxication capacity, in particular of the hepatic mesenchymal phagocytic system during a critical state. Cytokines and the primary LPS complex and its lipid A resp. are of basic importance. They start the release of a large amount of TNF alpha, IL-1, IL-6, IL-8 and other cascades. Acute shock is controlled nowadays more frequently than in the past, however, there is a high risk of a very adverse reaction of remote organs, which is very adverse from the prognostic aspect. A series of laboratory markers has a greater validity than the clinical picture alone. For screening derived markers are used not primary markers. Despite this they provide adequate information. Prophylaxis and treatment include selective bacterial decontamination, or active or passive immunization (PSAEVA, hyperimmune sera), minidoses of dopamine in a continuous infusion, early enteral nutritional intervention, in particular enteral nutrition containing glutamine. Monoclonal and polyclonal antibodies against the LPS complex and cytokines are tested, blocking their receptors or possibly early plasmapheresis. Permanent pillars of therapeutic tactics are still a radical and early elimination of possible infectious foci and targeted administration of antibiotics and maintenance of the perfusion pressure and adequate oxygenation.

Humans↗