JAK2-STAT Epigenetically Regulates Tolerized Genes in Monocytes in the First Encounter With Gram-Negative Bacterial Endotoxins in Sepsis

Microbial challenges, such as widespread bacterial infection in sepsis, induce endotoxin tolerance, a state of hyporesponsiveness to subsequent infections. The participation of DNA methylation in this process is poorly known. In this study, we perform integrated analysis of DNA methylation and transcriptional changes following in vitro exposure to gram-negative bacterial lipopolysaccharide, together with analysis of ex vivo monocytes from septic patients. We identify TET2-mediated demethylation and transcriptional activation of inflammation-related genes that is specific to toll-like receptor stimulation. Changes also involve phosphorylation of STAT1, STAT3 and STAT5, elements of the JAK2 pathway. JAK2 pathway inhibition impairs the activation of tolerized genes on the first encounter with lipopolysaccharide. We then confirm the implication of the JAK2-STAT pathway in the aberrant DNA methylome of patients with sepsis caused by gram-negative bacteria. Finally, JAK2 inhibition in monocytes partially recapitulates the expression changes produced in the immunosuppressive cellular state acquired by monocytes from gram-negative sepsis, as described by single cell-RNA-sequencing. Our study evidences both the crucial role the JAK2-STAT pathway in epigenetic regulation and initial response of the tolerized genes to gram-negative bacterial endotoxins and provides a pharmacological target to prevent exacerbated responses.

xperimental Evaluation of the Possibility of using the LAL test to Determine Bacterial Endotoxins in Vaccines for Rabies Prophylaxis

Relevance. The presence of pyrogenic impurities in finished dosage forms of concentrated cultural anti-rabies vaccines produced in the Russian Federation is determined using pyrogenicity tests on rabbits (in vivo). In accordance with the decision of the Board of the Eurasian Economic Commission dated September 7, 2018 N 151 «On the approval of guidelines for drawing up a regulatory document on the quality of a medicinal product», one of the requirements for parenteral drugs is the determination of bacterial endotoxins. This document indicates that the regulatory documentation should include a test and an admissibility criterion for bacterial endotoxins (BE) using the horseshoe crab amoebocyte lysate technique.Aims. Experimental evaluation of the possibility of using the LAL-test to determine bacterial endotoxins in national vaccines for the prevention of rabies.Materials and methods. The research of the drug «Cultural antirabies vaccine concentrated inactivated purified» of national production was carried out in accordance with the National Pharmacopoeia of the Russian Federation, General Pharmacopoeia Monograph OFS.1.2.4.0006.15 in three modifications: gel-clot test: methods A, B; turbidimetric kinetic test: method C; chromogenic kinetic test: method D.Results. Was investigated 6 series of the national vaccines for the prevention of rabies from two national manufacturers (using three pharmacopoeial methods). LAL reagent produced by two companies (Charles River Endosafe® and Lonza). In order to confirm the reproducibility of the method, the gel-clot test was carried out at different time intervals by one or two operators. During the research was determined the possibility of using photometric methods (method C and D).Conclusions. The research proved the possibility of determining bacterial endotoxins by methods: gel-clot test (method A), turbidimetric kinetic test (method C) and chromogenic kinetic test (method D). Method B is recommended for quantitative analysis of vaccine without instrumental methods. During the research all national vaccines for the prevention of rabies was free from bacterial endotoxins (no more 25 EU/ml).

The Regulation of Biological and other Innovative Medicinal Products

This chapter discusses the phrase ‘biological medicinal product’, which is used to refer to products manufactured by biological or biotechnology means or to advanced therapy medicinal products. It examines biological medicinal products that are considered peptides or proteins and are made up of one or more linear sequences of amino acids. It also talks about the compliance of biological products with a minimum quality standard set by the British Pharmacopoeia or European Pharmacopoeia, which includes specific instructions for testing sterility, bacterial endotoxins, microbial limits, volume in container, uniformity of dosage units, and particulate matter. The chapter highlights biological products that are manufactured using recombinant cells and are extracted or made from unaltered tissues or blood that are purified in the same way as recombinant products. It explores the inherent heterogeneity of biological products as it comprises of a mixture of closely related molecules.

Endogenous Regulation and Pharmacological Modulation of Sepsis-Induced HMGB1 Release and Action: An Updated Review

Sepsis remains a common cause of death in intensive care units, accounting for approximately 20% of total deaths worldwide. Its pathogenesis is partly attributable to dysregulated inflammatory responses to bacterial endotoxins (such as lipopolysaccharide, LPS), which stimulate innate immune cells to sequentially release early cytokines (such as tumor necrosis factor (TNF) and interferons (IFNs)) and late mediators (such as high-mobility group box 1, HMGB1). Despite difficulties in translating mechanistic insights into effective therapies, an improved understanding of the complex mechanisms underlying the pathogenesis of sepsis is still urgently needed. Here, we review recent progress in elucidating the intricate mechanisms underlying the regulation of HMGB1 release and action, and propose a few potential therapeutic candidates for future clinical investigations.

Role of acute respiratory diseases in pathogenesis of distal limb infections in cattle

According to current concepts, ruminal and metabolic acidosis occur due to feeding cattle mainly with preserved acidic feeds such as silage and haylage. However, errors in feeding are not the only etiological factor leading to acidosis. In some cases, metabolic acidosis in cattle can develop along with respiratory infection caused by viral and bacterial agents. The main pathological processes resulting from acute respiratory diseases of cattle are bronchitises, tracheites and pneumonias. When the respiratory tract is affected in cattle, hypoxia occurs, causing intoxication and, thus, leading to ruminal acidosis. As a result, vasoactive substances (bacterial endotoxins, histamine, lactate) enter the bloodstream, the vascular endothelium is damaged due to the simultaneous expansion of arterioles and compression of venules, blood fluid is perfused from the vessels into the surrounding tissues, the blood flow in the microcirculatory bed is disrupted. An important role in the disturbance of blood circulation in small blood vessels is played by circulating immune complexes representing the «antigen-antibody» complex. Low molecular weight circulating immune complexes settle in various organs and tissues of the body, lead to inflammation and damage the normal tissue structure. Most frequently, immune complexes affect the endothelium of blood vessels, renal glomeruli and joints. Distal limb vessels are primarily affected in cattle, leading to disturbance of skin trophism of the limbs and hooves, development of laminitis, while the hoof horn is weakly keratinized and cannot resist aggressive mechanical and chemical environmental factors. Damaged hooves are the gateway of infection for the agents of necrobacteriosis (Fusobacterium necrophorum), staphylococcosis (Staphylococcus spp.), streptococcosis (Streptococcus spp.) and other pathogens. In addition, favorable conditions evolve for the development of mixed infection due to reduction in the overall organism resistance, which is observed for both respiratory and distal limb infections.

Pathological and Therapeutic Approach to Endotoxin-Secreting Bacteria Involved in Periodontal Disease

It is widely recognized that periodontal disease is an inflammatory entity of infectious origin, in which the immune activation of the host leads to the destruction of the supporting tissues of the tooth. Periodontal pathogenic bacteria like Porphyromonas gingivalis, that belongs to the complex net of oral microflora, exhibits a toxicogenic potential by releasing endotoxins, which are the lipopolysaccharide component (LPS) available in the outer cell wall of Gram-negative bacteria. Endotoxins are released into the tissues causing damage after the cell is lysed. There are three well-defined regions in the LPS: one of them, the lipid A, has a lipidic nature, and the other two, the Core and the O-antigen, have a glycosidic nature, all of them with independent and synergistic functions. Lipid A is the “bioactive center” of LPS, responsible for its toxicity, and shows great variability along bacteria. In general, endotoxins have specific receptors at the cells, causing a wide immunoinflammatory response by inducing the release of pro-inflammatory cytokines and the production of matrix metalloproteinases. This response is not coordinated, favoring the dissemination of LPS through blood vessels, as well as binding mainly to Toll-like receptor 4 (TLR4) expressed in the host cells, leading to the destruction of the tissues and the detrimental effect in some systemic pathologies. Lipid A can also act as a TLRs antagonist eliciting immune deregulation. Although bacterial endotoxins have been extensively studied clinically and in a laboratory, their effects on the oral cavity and particularly on periodontium deserve special attention since they affect the connective tissue that supports the tooth, and can be linked to advanced medical conditions. This review addresses the distribution of endotoxins associated with periodontal pathogenic bacteria and its relationship with systemic diseases, as well as the effect of some therapeutic alternatives.

Two Sides to Every Question: Attempts to Activate Chicken Innate Immunity in 2D and 3D Hepatic Cell Cultures

The liver with resident tissue macrophages is the site of vivid innate immunity, activated also by pathogen-associated molecular patterns (PAMPs) leaking through the intestinal barrier. As gut-derived inflammatory diseases are of outstanding importance in broiler chickens, the present study aimed to establish a proper hepatic inflammatory model by comparing the action of different PAMPs from poultry pathogens on chicken 2D and 3D primary hepatocyte—non-parenchymal cell co-cultures, the latter newly developed with a magnetic bioprinting method. The cultures were challenged by the bacterial endotoxins lipopolysaccharide (LPS) from Escherichia coli, lipoteichoic acid (LTA) from Staphylococcus aureus and by enterotoxin (ETxB) from Escherichia coli, Salmonella Typhimurium derived flagellin, phorbol myristate acetate (PMA) as a model proinflammatory agent and polyinosinic polycytidylic acid (poly I:C) for mimicking viral RNA exposure. Cellular metabolic activity was assessed with the CCK-8 test, membrane damage was monitored with the lactate dehydrogenase (LDH) leakage assay and interleukin-6 and -8 (Il-6 and -8) concentrations were measured in cell culture medium with a chicken specific ELISA. Both LPS and LTA increased the metabolic activity of the 3D cultures, concomitantly decreasing the LDH leakage, while in 2D cultures ETxB stimulated, PMA and poly I:C depressed the metabolic activity. Based on the moderately increased extracellular LDH activity, LTA seemed to diminish cell membrane integrity in 2D and poly I:C in both cell culture models. The applied endotoxins remarkably reduced the IL-8 release of 3D cultured cells, suggesting the effective metabolic adaptation and the presumably initiated anti-inflammatory mechanisms of the 3D spheroids. Notwithstanding that the IL-6 and IL-8 production of 2D cells was mostly not influenced by the endotoxins used, only the higher LTA dose was capable to evoke an IL-8 surge. Flagellin, PMA and poly I:C exerted proinflammatory action in certain concentrations in both 2D and 3D cultures, reflected by the increased cellular IL-6 release. Based on these data, LTA, flagellin, PMA and poly I:C can be considered as potent candidates to induce inflammation in chicken primary hepatic cell cultures, while LPS failed to trigger proinflammatory cytokine production, suggesting the relatively high tolerance of avian liver cells to certain bacterial endotoxins. These results substantiate that the established 3D co-cultures seemed to be proper tools for testing potential proinflammatory molecules; however, the remarkable differences between 2D and 3D models should be addressed and further studied.

Highly Sensitive Detection and Differentiation of Endotoxins Derived from Bacterial Pathogens by Surface-Enhanced Raman Scattering

Bacterial endotoxins, as major components of Gram-negative bacterial outer membrane leaflets and a well-characterized TLR4-MD-2 ligand, are lipopolysaccharides (LPSs) that are constantly shed from bacteria during growth and infection. For the first time, we report that unique surface-enhanced Raman scattering (SERS) spectra of enteric LPSs from E. coli, S. typhimurium, S. minnesota, V. cholerae, Rhizobium species R. CE3, and R. NGR, as well as Neisseria meningitidis endotoxin structures, LPSs, lipid A, and KDO2-lipid A can be obtained. The characteristic peaks of the SERS spectra reveal that most of the tested LPS structures are from lipids and saccharides, i.e., the major components of LPSs, and these spectra can be successfully used to differentiate between endotoxins with principal components analysis. In addition, all the LPS samples here are measured at a concentration of 10 nmole/mL, which corresponds to their relevant pathophysiological concentrations in clinical infections. This study demonstrates that LPSs can be used as biomarkers for the highly sensitive detection of bacteria using SERS-based methods.

Detection of Pyrogens in Hormonal Implants Using the LAL Test

The State Pharmacopoeia of the Russian Federation, 14th edition states that implants are a sterile dosage form, and have to be tested for pyrogens. However, it does not provide details on how the test should be performed for this dosage form.The aim of the study was to develop a LAL test procedure for detection of bacterial endotoxins (BE) in implants, using the example of a goserelin product.Materials and methods: BE extraction from the implant surface into an aqueous medium was performed with subsequent BE detection in the extract by turbidimetric kinetic test. The implant was then dissolved in dimethyl sulfoxide, and the obtained goserelin solution was tested for BEs using the gel-clot test.Results: the analysis of the Russian and foreign pharmacopoeial approaches to pyrogenic substance detection in hormonal implants helped to develop two sample preparation procedures for determination of BE content (in the extract and the implant solution). It was demonstrated that the BE content in the water extract did not exceed 0.01 EU/mL and was less than 0.07 EU per implant. The BE content in the implant solution was less than 8.3 EU per 1 mg of goserelin, which is almost eleven-fold lower than the theoretically-derived limit.Conclusions: the authors developed two test procedures for BE detection in hormonal implants using the LAL test, which could be included in manufacturers’ product files. The first procedure involves testing of the water extract from the implant surface and establishes the BE limit of no more than 20 EU/product. The second procedure involves complete dissolution of the implant in dimethyl sulfoxide and establishes the limit of not more than 97.22 EU per 1 mg of goserelin.