Monocytic Thrombomodulin Triggers LPS- and Gram-Negative Bacteria-Induced Inflammatory Response

Infections of the reproductive tract or mammary gland with Gram-negative bacteria perturb ovarian function, follicular growth, and fecundity in cattle. We hypothesized that lipopolysaccharide (LPS) from Gram-negative bacteria stimulates an inflammatory response by ovarian granulosa cells that is mediated by Toll-like receptor (TLR) 4. The present study tested the capacity of bovine ovarian granulosa cells to initiate an inflammatory response to pathogen-associated molecular patterns and determined subsequent effects on the in vitro maturation of oocytes. Granulosa cells elicited an inflammatory response to pathogen-associated molecular patterns (LPS, lipoteichoic acid, peptidoglycan, or Pam3CSK4) with accumulation of the cytokine IL-6, and the chemokine IL-8, in a time- and dose-dependent manner. Granulosa cells responded acutely to LPS with rapid phosphorylation of TLR signaling components, p38 and ERK, and increased expression of IL6 and IL8 mRNA, although nuclear translocation of p65 was not evident. Targeting TLR4 with small interfering RNA attenuated granulosa cell accumulation of IL-6 in response to LPS. Endocrine function of granulosa cells is regulated by FSH, but here, FSH also enhanced responsiveness to LPS, increasing IL-6 and IL-8 accumulation. Furthermore, LPS stimulated IL-6 secretion and expansion by cumulus-oocyte complexes and increased rates of meiotic arrest and germinal vesicle breakdown failure. In conclusion, bovine granulosa cells initiate an innate immune response to LPS via the TLR4 pathway, leading to inflammation and to perturbation of meiotic competence.

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A Protocol to Perform Systemic Lipopolysacharide (LPS) Challenge in Rats

Odovtos - International Journal of Dental Sciences ◽

10.15517/ijds.v21i1.35510 ◽

2019 ◽

Vol 21 (1) ◽

pp. 53-66

Author(s):

Karol Ramírez DDS, MSc, PhD ◽

Daniel Quesada-Yamasaki MLS ◽

Jaime Fornaguera-Trías PhD

Keyword(s):

Innate Immunity ◽

Inflammatory Response ◽

Intraperitoneal Administration ◽

Sickness Behavior ◽

Gram Negative Bacteria ◽

Inflammatory Stimulus ◽

Gram Negative ◽

Lps Challenge ◽

Scientific Questions ◽

Pro Inflammatory Cytokines

Lipopolysaccharide (LPS) is a component of the outer membrane of Gram-negative bacteria. In animals, intraperitoneal administration of LPS, stimulates innate immunity and the production of pro-inflammatory cytokines. LPS provides an inflammatory stimulus that activates the neuroimmune and neuroendocrine systems resulting in a set of responses termed sickness behavior. The purpose of this protocol is to describe step-by-step the preparation and procedure of application of intraperitoneal injection of LPS in rats, as a guide for those researchers that want to use this assay to mount an inflammatory response. LPS intraperitoneal challenge in rats has been widely used to evaluate anti-inflammatory reagents and to address basic scientific questions.

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Tenascin-C Deficiency Is Associated With Reduced Bacterial Outgrowth During Klebsiella pneumoniae-Evoked Pneumosepsis in Mice

Frontiers in Immunology ◽

10.3389/fimmu.2021.600979 ◽

2021 ◽

Vol 12 ◽

Author(s):

Mariska T. Meijer ◽

Alex F. de Vos ◽

Brendon P. Scicluna ◽

Joris J. Roelofs ◽

Chérine Abou Fayçal ◽

...

Keyword(s):

Klebsiella Pneumoniae ◽

Inflammatory Response ◽

Organ Injury ◽

Gram Negative Bacteria ◽

Lung Pathology ◽

Gram Negative ◽

Tenascin C ◽

Protein Levels ◽

Bacterial Outgrowth

Tenascin C (TNC) is an extracellular matrix glycoprotein that recently emerged as an immunomodulator. TNC-deficient (TNC−/−) mice were reported to have a reduced inflammatory response upon systemic administration of lipopolysaccharide, the toxic component of gram-negative bacteria. Here, we investigated the role of TNC during gram-negative pneumonia derived sepsis. TNC+/+ and TNC−/− mice were infected with Klebsiella pneumoniae via the airways and sacrificed 24 and 42 h thereafter for further analysis. Pulmonary TNC protein levels were elevated 42 h after infection in TNC+/+ mice and remained undetectable in TNC−/− mice. TNC−/− mice showed modestly lower bacterial loads in lungs and blood, and a somewhat reduced local—but not systemic—inflammatory response. Moreover, TNC−/− and TNC+/+ mice did not differ with regard to neutrophil recruitment, lung pathology or plasma markers of distal organ injury. These results suggest that while TNC shapes the immune response during lipopolysaccharide-induced inflammation, this role may be superseded during pneumosepsis caused by a common gram-negative pathogen.

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Biofilms Formed by Gram-Negative Bacteria Undergo Increased Lipid A Palmitoylation, Enhancing In Vivo Survival

mBio ◽

10.1128/mbio.01116-14 ◽

2014 ◽

Vol 5 (4) ◽

Cited By ~ 35

Author(s):

Sabina Chalabaev ◽

Ashwini Chauhan ◽

Alexey Novikov ◽

Pavithra Iyer ◽

Magdalena Szczesny ◽

...

Keyword(s):

Inflammatory Response ◽

Lipid A ◽

Acyl Chain ◽

Bacterial Biofilm ◽

Gram Negative Bacteria ◽

Gram Negative ◽

Content Type ◽

Planktonic Bacteria ◽

Biofilm Bacteria

ABSTRACTBacterial biofilm communities are associated with profound physiological changes that lead to novel properties compared to the properties of individual (planktonic) bacteria. The study of biofilm-associated phenotypes is an essential step toward control of deleterious effects of pathogenic biofilms. Here we investigated lipopolysaccharide (LPS) structural modifications in Escherichia coli biofilm bacteria, and we showed that all tested commensal and pathogenic E. coli biofilm bacteria display LPS modifications corresponding to an increased level of incorporation of palmitate acyl chain (palmitoylation) into lipid A compared to planktonic bacteria. Genetic analysis showed that lipid A palmitoylation in biofilms is mediated by the PagP enzyme, which is regulated by the histone-like protein repressor H-NS and the SlyA regulator. While lipid A palmitoylation does not influence bacterial adhesion, it weakens inflammatory response and enhances resistance to some antimicrobial peptides. Moreover, we showed that lipid A palmitoylation increasesin vivosurvival of biofilm bacteria in a clinically relevant model of catheter infection, potentially contributing to biofilm tolerance to host immune defenses. The widespread occurrence of increased lipid A palmitoylation in biofilms formed by all tested bacteria suggests that it constitutes a new biofilm-associated phenotype in Gram-negative bacteria.IMPORTANCEBacterial communities called biofilms display characteristic properties compared to isolated (planktonic) bacteria, suggesting that some molecules could be more particularly produced under biofilm conditions. We investigated biofilm-associated modifications occurring in the lipopolysaccharide (LPS), a major component of all Gram-negative bacterial outer membrane. We showed that all tested commensal and pathogenic biofilm bacteria display high incorporation of a palmitate acyl chain into the lipid A part of LPS. This lipid A palmitoylation is mediated by the PagP enzyme, whose expression in biofilm is controlled by the regulatory proteins H-NS and SlyA. We also showed that lipid A palmitoylation in biofilm bacteria reduces host inflammatory response and enhances their survival in an animal model of biofilm infections. While these results provide new insights into the biofilm lifestyle, they also suggest that the level of lipid A palmitoylation could be used as an indicator to monitor the development of biofilm infections on medical surfaces.

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Effect of hemorrhagic shock on gut barrier function and expression of stress-related genes in normal and gnotobiotic mice

AJP Regulatory Integrative and Comparative Physiology ◽

10.1152/ajpregu.00278.2002 ◽

2002 ◽

Vol 283 (5) ◽

pp. R1263-R1274 ◽

Cited By ~ 33

Author(s):

Runkuan Yang ◽

David J. Gallo ◽

Jeffrey J. Baust ◽

Simon K. Watkins ◽

Russell L. Delude ◽

...

Keyword(s):

Inflammatory Response ◽

Hemorrhagic Shock ◽

Gram Negative Bacteria ◽

Mrna Levels ◽

Mucosal Permeability ◽

Tissue Samples ◽

Gram Negative ◽

Gut Barrier Function ◽

Cox 2 ◽

Gnotobiotic Mice

We sought to determine whether gut-derived microbial factors influence the hepatic or intestinal inflammatory response to hemorrhagic shock and resuscitation (HS/R). Conventional and gnotobiotic mice contaminated with a defined microbiota without gram-negative bacteria were subjected to either a sham procedure or HS/R. Tissue samples were obtained 4 h later for assessing ileal mucosal permeability to FITC dextran and hepatic and ileal mucosal steady-state IL-6, inducible nitric oxide synthase (iNOS), cyclooxygenase (COX)-2, and TNF mRNA levels. Whereas HS/R significantly increased ileal mucosal permeability in conventional mice, this effect was not apparent in gnotobiotic animals. HS/R markedly increased hepatic mRNA levels for several proinflammatory genes in both conventional and gnotobiotic mice. HS/R increased ileal mucosal IL-6 and COX-2 mRNA expression in conventional but not gnotobiotic mice. If gnotobiotic mice were contaminated with Escherichia coli C25, HS/R increased ileal mucosal permeability and upregulated expression of IL-6 and COX-2. These data support the view that the hepatic inflammatory response to HS/R is largely independent of the presence of potentially pathogenic gram-negative bacteria colonizing the gut, whereas the local mucosal response to HS/R is profoundly influenced by the microbial ecology within the lumen during and shortly after the period of hemorrhage.

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Bacterial-Mucosal Cell Junctional Complexes

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100050731 ◽

1974 ◽

Vol 32 ◽

pp. 144-145

Author(s):

Roger C. Wagner

Keyword(s):

Intestinal Wall ◽

Rat Colon ◽

Mucosal Cell ◽

Gram Negative Bacteria ◽

Gram Negative ◽

Mucosal Cells ◽

Mucosal Lining ◽

Degenerative Alterations ◽

Junctional Complexes ◽

Intestinal Mucosal Cells

Bacteria exhibit the ability to adhere to the apical surfaces of intestinal mucosal cells. These attachments either precede invasion of the intestinal wall by the bacteria with accompanying inflammation and degeneration of the mucosa or represent permanent anchoring sites where the bacteria never totally penetrate the mucosal cells.Endemic gram negative bacteria were found attached to the surface of mucosal cells lining the walls of crypts in the rat colon. The bacteria did not intrude deeper than 0.5 urn into the mucosal cells and no degenerative alterations were detectable in the mucosal lining.

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Rapid demonstration of septic or infectious arthritis due to Gram-negative bacteria

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100123830 ◽

1992 ◽

Vol 50 (1) ◽

pp. 686-687

Author(s):

Jacob S. Hanker ◽

Paul R. Gross ◽

Beverly L. Giammara

Keyword(s):

Chronic Arthritis ◽

Blood Cultures ◽

Gram Negative Bacteria ◽

Infectious Arthritis ◽

Bacterial Arthritis ◽

Gram Positive ◽

Gram Negative ◽

Gram Positive Bacteria

Blood cultures are positive in approximately only 50 per cent of the patients with nongonococcal bacterial infectious arthritis and about 20 per cent of those with gonococcal arthritis. But the concept that gram-negative bacteria could be involved even in chronic arthritis is well-supported. Gram stains are more definitive in staphylococcal arthritis caused by gram-positive bacteria than in bacterial arthritis due to gram-negative bacteria. In the latter situation where gram-negative bacilli are the problem, Gram stains are helpful for 50% of the patients; they are only helpful for 25% of the patients, however, where gram-negative gonococci are the problem. In arthritis due to gram-positive Staphylococci. Gramstained smears are positive for 75% of the patients.

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Ultrastructure of periplasmic bodies in gram-negative bacteria

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100160753 ◽

1990 ◽

Vol 48 (3) ◽

pp. 640-641

Author(s):

Xie Nianming ◽

Ding Shaoqing ◽

Wang Luping ◽

Yuan Zenglin ◽

Zhan Guolai ◽

...

Keyword(s):

Electron Microscope ◽

Campylobacter Jejuni ◽

Proteus Mirabilis ◽

Shigella Flexneri ◽

Morphological Description ◽

Gram Negative Bacteria ◽

Periplasmic Space ◽

Clostridium Tetani ◽

Gram Negative ◽

Brucella Canis

Perhaps the data about periplasmic enzymes are obtained through biochemical methods but lack of morphological description. We have proved the existence of periplasmic bodies by electron microscope and described their ultrastructures. We hope this report may draw the attention of biochemists and mrophologists to collaborate on researches in periplasmic enzymes or periplasmic bodies with each other.One or more independent bodies may be seen in the periplasmic space between outer and inner membranes of Gram-negative bacteria, which we called periplasmic bodies. The periplasmic bodies have been found in seven species of bacteria at least, including the Pseudomonas aeroginosa. Shigella flexneri, Echerichia coli. Yersinia pestis, Campylobacter jejuni, Proteus mirabilis, Clostridium tetani. Vibrio cholerae and Brucella canis.

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Dual stain kit for the microscopic gram classification of ocular infection bacteria

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100147089 ◽

1993 ◽

Vol 51 ◽

pp. 248-249

Author(s):

Jacob S. Hanker ◽

Dale N. Holdren ◽

Kenneth L. Cohen ◽

Beverly L. Giammara

Keyword(s):

Contact Lenses ◽

Ocular Infection ◽

Gram Negative Bacteria ◽

Gram Negative ◽

Gram Staining ◽

Ocular Infections ◽

Different Types ◽

Culture Positive ◽

Increased Susceptibility

Keratitis and conjunctivitis (infections of the cornea or conjunctiva) are ocular infections caused by various bacteria, fungi, viruses or parasites; bacteria, however, are usually prominent. Systemic conditions such as alcoholism, diabetes, debilitating disease, AIDS and immunosuppressive therapy can lead to increased susceptibility but trauma and contact lens use are very important factors. Gram-negative bacteria are most frequently cultured in these situations and Pseudomonas aeruginosa is most usually isolated from culture-positive ulcers of patients using contact lenses. Smears for staining can be obtained with a special swab or spatula and Gram staining frequently guides choice of a therapeutic rinse prior to the report of the culture results upon which specific antibiotic therapy is based. In some cases staining of the direct smear may be diagnostic in situations where the culture will not grow. In these cases different types of stains occasionally assist in guiding therapy.

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