Immunization with a peptide mimicking lipoteichoic acid induces memory B cells in BALB/c mice.

BACKGROUND: There is an urgent clinical need for developing novel immunoprophylaxis and immunotherapy strategies against Staphylococcus aureus (S. aureus). In our previous work, immunization with a tetra-branched multiple antigenic peptide, named MAP2-3 that mimics lipoteichoic acid, a cell wall component of S. aureus, successfully induced a humoral immune response and protected BALB/c mice against S. aureus systemic infection. In this study, we further investigated whether vaccination with MAP2-3 can elicit immunologic memory. METHODS: BALB/c mice were immunized with MAP2-3 five times. After one month of the last vaccination, mice were challenged with heat-killed S. aureus via intraperitoneal injection. After a 7-day inoculation, the percentage of plasma cells, memory B cells, effector memory T cells, and follicular helper T cells were detected by flow cytometry. The levels of IL-6, IL-21, IL-2, and IFN-γ were measured by real-time PCR and ELISA. Flow cytometry results were compared by using one-way ANOVA or Mann-Whitney test, real-time PCR results were compared by using one-way ANOVA, and ELISA results were compared by using one-way ANOVA or student's t-test. RESULTS: The percentage of plasma cells and memory B cells in the spleen and bone marrow from the MAP2-3 immunized mice was significantly higher than that from the control mice. The percentage of effector memory T cells in spleens and lymphoid nodes as well as follicular helper T cells in spleens from the MAP2-3 immunized mice were also higher. Moreover, the levels of IL-6 and IL-21, two critical cytokines for the development of memory B cells, were significantly higher in the isolated splenocytes from immunized mice after lipoteichoic acid stimulation. CONCLUSIONS: Immunization with MAP2-3 can efficiently induce memory B cells and memory T cells.

The antioxidant N-acetyl cysteine inhibits cytokine and prostaglandin release in human fetal membranes stimulated ex vivo with lipoteichoic acid or live group B streptococcus.

BACKGROUNDS: Infection during pregnancy is a significant public health concern due to the increased risk of adverse birth outcomes. Group B Streptococcus or Streptococcus agalactiae (GBS) stands out as a major bacterial cause of neonatal morbidity and mortality. We aimed to explore the involvement of reactive oxygen species (ROS) and oxidative stress pathways in pro-inflammatory responses within human fetal membrane tissue, the target tissue of acute bacterial chorioamnionitis. METHODS: We reanalyzed transcriptomic data from fetal membrane explants inoculated with GBS to assess the impact of GBS on oxidative stress and ROS genes/pathways. We conducted pathway enrichment analysis of transcriptomic data using the Database for Annotation, Visualization and Integrated Discovery (DAVID), a web-based functional annotation/pathway enrichment tool. Subsequently, we conducted ex vivo experiments to test the hypothesis that antioxidant treatment could inhibit pathogen-stimulated inflammatory responses in fetal membranes. RESULTS: Using DAVID analysis, we found significant enrichment of pathways related to oxidative stress or ROS in GBS-inoculated human fetal membranes, for example, "Response to Oxidative Stress" (FDR = 0.02) and "Positive Regulation of Reactive Oxygen Species Metabolic Process" (FDR = 2.6*10-4 ). There were 31 significantly changed genes associated with these pathways, most of which were upregulated after GBS inoculation. In ex vivo experiments with choriodecidual membrane explants, our study showed that co-treatment with N-acetylcysteine (NAC) effectively suppressed the release of pro-inflammatory cytokines (IL-6, IL-8, TNF-α) and prostaglandin PGE2, compared to GBS-treated explants (p < .05 compared to GBS-treated samples without NAC co-treatment). Furthermore, NAC treatment inhibited the release of cytokines and PGE2 stimulated by lipoteichoic acid (LTA) and lipopolysaccharide (LPS) in whole membrane explants (p < .05 compared to LTA or LPS-treated samples without NAC co-treatment). CONCLUSIONS: Our study sheds light on the potential roles of ROS in governing the innate immune response to GBS infection, offering insights for developing strategies to mitigate GBS-related adverse outcomes.

Lipoteichoic acid restrains macrophage senescence via ß-catenin/FOXO1/REDD1 pathway in age-related osteoporosis.

Osteoporosis and its related fractures are common causes of morbidity and mortality in older adults, but its underlying molecular and cellular mechanisms remain largely unknown. In this study, we found that lipoteichoic acid (LTA) treatment could ameliorate age-related bone degeneration and attenuate intramedullary macrophage senescence. FOXO1 signaling, which was downregulated and deactivated in aging macrophages, played a key role in the process. Blocking FOXO1 signaling caused decreased REDD1 expression and increased phosphorylation level of mTOR, a major driver of aging, as well as aggravated bone loss and deteriorated macrophage senescence. Moreover, LTA elevated FOXO1 signaling through ß-catenin pathway while ß-catenin inhibition significantly suppressed FOXO1 signaling, promoted senescence-related protein expression, and accelerated bone degeneration and macrophage senescence. Our findings indicated that ß-catenin/FOXO1/REDD1 signaling plays a physiologically significant role that protecting macrophages from senescence during aging.

Insight into the structure, biosynthesis, isolation method and biological function of teichoic acid in different gram-positive microorganisms: A review.

Teichoic acid (TA) is a weakly anionic polymer present in the cell walls of Gram-positive bacteria. It can be classified into wall teichoic acid (WTA) and lipoteichoic acid (LTA) based on its localization in the cell wall. The structure and biosynthetic pathway of TAs are strain-specific and have a significant role in maintaining cell wall stability. TAs have various beneficial functions, such as immunomodulatory, anticancer and antioxidant activities. However, the purity and yield of TAs are generally not high, and different isolation methods may even affect their structural integrity, which limits the research progress on the probiotic functions of TA. This paper reviews an overview of the structure and biosynthetic pathway of TAs in different strains, as well as the research progress of the isolation and purification methods of TAs. Furthermore, this review also highlights the current research status on the biological functions of TAs. Through a comprehensive understanding of this review, it is expected to pave the way for advancements in isolating and purifying high-quality TAs and, in turn, lay a foundation for contributing to the development of targeted probiotic therapies.

Early effects of lipoteichoic acid from Staphylococcus aureus on milk production-related signaling pathways in mouse mammary epithelial cells.

Staphylococcus aureus causes subclinical mastitis; lipoteichoic acid (LTA) from S. aureus causes mastitis-like adverse effects on milk production by mammary epithelial cells (MECs). Here, we investigated the early effects of LTA from S. aureus on mouse MECs using a culture model, in which MECs produced milk components and formed less permeable tight junctions (TJs). In MECs of this model, Toll-like receptor 2 (receptor for LTA), was localized on the apical membrane, similar to MECs in lactating mammary glands. LTA weakened the TJ barrier within 1 h, concurrently with localization changes of claudin 4. LTA treatment for 24 h increased αS1-casein and decreased ß-casein levels. In MECs exposed to LTA, the activation level of signal transducer and activator of transcription 5 (major transcriptional factor for milk production) was low. LTA activated signaling pathways related to cell survival (extracellular signal-regulated kinase, heat shock protein 27, and Akt) and inflammation (p38, c-Jun N-terminal kinase, and nuclear factor κB). Thus, LTA caused abnormalities in casein production and weakened the TJs by affecting multiple signaling pathways in MECs. LTA-induced changes in signaling pathways were not uniform in all MECs. Such complex and semi-negative actions of LTA may contribute to subclinical mastitis caused by S. aureus.

Myeloid liver kinase B1 contributes to lung inflammation induced by lipoteichoic acid but not by viable Streptococcus pneumoniae.

BACKGROUND: Liver kinase B1 (Lkb1, gene name Stk11) functions as a tumor suppressor in cancer. Myeloid cell Lkb1 potentiates lung inflammation induced by the Gram-negative bacterial cell wall component lipopolysaccharide and in host defense during Gram-negative pneumonia. Here, we sought to investigate the role of myeloid Lkb1 in lung inflammation elicited by the Gram-positive bacterial cell wall component lipoteichoic acid (LTA) and during pneumonia caused by the Gram-positive respiratory pathogen Streptococcus pneumoniae (Spneu). METHODS: Alveolar and bone marrow derived macrophages (AMs, BMDMs) harvested from myeloid-specific Lkb1 deficient (Stk11-ΔM) and littermate control mice were stimulated with LTA or Spneu in vitro. Stk11-ΔM and control mice were challenged via the airways with LTA or infected with Spneu in vivo. RESULTS: Lkb1 deficient AMs and BMDMs produced less tumor necrosis factor (TNF)α upon activation by LTA or Spneu. During LTA-induced lung inflammation, Stk11-ΔM mice had reduced numbers of AMs in the lungs, as well as diminished cytokine release and neutrophil recruitment into the airways. During pneumonia induced by either encapsulated or non-encapsulated Spneu, Stk11-ΔM and control mice had comparable bacterial loads and inflammatory responses in the lung, with the exception of lower TNFα levels in Stk11-ΔM mice after infection with the non-encapsulated strain. CONCLUSION: Myeloid Lkb1 contributes to LTA-induced lung inflammation, but is not important for host defense during pneumococcal pneumonia.

Extracellular Hsp70 modulates 16HBE cells' inflammatory responses to cigarette smoke and bacterial components lipopolysaccharide and lipoteichoic acid.

Cigarette smoke is a major risk factor for chronic obstructive pulmonary disease (COPD), leading to chronic inflammation, while bacterial components lipopolysaccharide (LPS) and lipoteichoic acid (LTA) are often present in airways of COPD patients, especially during exacerbations.We hypothesised that extracellular heat shock protein 70 (eHsp70), a damage-associated molecular pattern elevated in serum of COPD patients, induces inflammation and alters cigarette smoke and LPS/LTA-induced inflammatory effects in the airway epithelium.We used 16HBE cells exposed to recombinant human (rh)Hsp70 and its combinations with cigarette smoke extract (CSE), LPS or LTA to investigate those assumptions, and we determined pro-inflammatory cytokines' secretion as well as TLR2 and TLR4 gene expression.rhHsp70 and CSE alone stimulated IL-6, IL-8 and TNF-α secretion. CSE and rhHsp70 had antagonistic effect on IL-6 secretion, while combinations of LPS or LTA with rhHsp70 showed antagonistic effect on TNF-α release. By using specific inhibitors, we demonstrated that effects of rhHsp70 on cytokines' secretion were mediated via NF-κB and/or MAPK signalling pathways. rhHsp70 increased, and CSE decreased TLR2 gene expression compared to untreated cells, but their combinations increased it compared to CSE alone. LPS and rhHsp70 combinations decreased TLR2 gene expression compared to untreated cells. TLR4 expression was not induced by any of the treatments.In conclusion, we demonstrated that extracellular Hsp70 modulates pro-inflammatory responses of human airway epithelial cells to cigarette smoke and bacterial components LPS and LTA. Simultaneous presence of those compounds and their interactions might lead to inappropriate immune responses and adverse consequences in COPD.

Anti-Inflammatory Mechanism of An Alkaloid Rutaecarpine in LTA-Stimulated RAW 264.7 Cells: Pivotal Role on NF-κB and ERK/p38 Signaling Molecules.

Lipoteichoic acid (LTA) is a key cell wall component and virulence factor of Gram-positive bacteria. LTA contributes a major role in infection and it mediates inflammatory responses in the host. Rutaecarpine, an indolopyridoquinazolinone alkaloid isolated from Evodia rutaecarpa, has shown a variety of fascinating biological properties such as anti-thrombotic, anticancer, anti-obesity and thermoregulatory, vasorelaxing activity. It has also potent effects on the cardiovascular and endocrine systems. Herein, we investigated rutaecarpine's (Rut) anti-inflammatory effects in LTA-stimulated RAW macrophage cells. The Western blot and spectrophotometric results revealed that Rut inhibited the production of nitric oxide (NO) and the expression of inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), and interleukin (IL)-1ß in the LTA-induced macrophage cells. Successively, our mechanistic studies publicized that Rut inhibited LTA-induced phosphorylation of mitogen-activated protein kinase (MAPK) including the extracellular signal-regulated kinase (ERK), and p38, but not c-Jun NH2-terminal kinase (JNK). In addition, the respective Western blot and confocal image analyses exhibited that Rut reserved nuclear transcription factor kappa-B (NF-κB) by hindering inhibitor of nuclear factor κB-α (IκBα) and NF-κB p65 phosphorylation and p65 nuclear translocation. These results indicate that Rut exhibits its anti-inflammatory effects mainly through attenuating NF-κB and ERK/p38 signaling pathways. Overall, this result suggests that Rut could be a potential therapeutic agent for the treatment of Gram-positive bacteria induced inflammatory diseases.

Levilactobacillus brevis KU15151 Inhibits Staphylococcus aureus Lipoteichoic Acid-Induced Inflammation in RAW 264.7 Macrophages.

Inflammation is a host defense response to harmful agents, such as pathogenic invasion, and is necessary for health. Excessive inflammation may result in the development of inflammatory disorders. Levilactobacillus brevis KU15151 has been reported to exhibit probiotic characteristics and antioxidant activities, but the effect of this strain on inflammatory responses has not been determined. The present study aimed to investigate the anti-inflammatory potential of L. brevis KU15151 in Staphylococcus aureus lipoteichoic acid (aLTA)-induced RAW264.7 macrophages. Treatment with L. brevis KU15151 reduced the production of nitric oxide and prostaglandin E2 by suppressing the expression of inducible nitric oxide synthase and cyclooxygenase-2. Additionally, the production of proinflammatory cytokines including tumor necrosis factor-α, interleukin (IL)-6, and IL-1ß, decreased after treatment with L. brevis KU15151 in aLTA-stimulated RAW 264.7 cells. Furthermore, this strain alleviated the activation of nuclear factor-κB and mitogen-activated protein kinase signaling pathways. Moreover, the generation of reactive oxygen species was downregulated by treatment with L. brevis KU15151. These results demonstrate that L. brevis KU15151 possesses an inhibitory effect against aLTA-mediated inflammation and may be employed as a functional probiotic for preventing inflammatory disorders.

Gram-positive Staphylococcus aureus LTA promotes distinct memory-like effects in murine bone marrow neutrophils.

Neutrophils primarily act as first responders in acute infection and directly maintain inflammatory responses. However, a growing body of evidence suggests that neutrophils also bear the potential to mediate chronic inflammation by exhibiting memory-like features. We now asked whether bone marrow-derived murine neutrophils can be primed by lipoteichoic acid (LTA) from gram-positive S. aureus. We found that low-dose (1 ng/mL) LTA-priming promoted increased production of pro-inflammatory mediators (TNF-α, IL-6, ROS), whereas high-dose (10 µg/mL) priming resulted in opposing reactions marked by increased IL-10 and suppressed pro-inflammatory mediators upon a second stimulus. A similar pattern of pro-inflammatory activation (trained sensitivity) and anti-inflammatory properties (tolerance) was recapitulated in cellular functional in vitro assays (transmigration and phagocytosis). Priming by LTA correlated with TLR2/MyD88-mediated regulation of NFκB-p65 through intermediate PI3Ks/MAPK. Collectively, our data suggest a previously unknown capacity of neutrophils to be differentially primed by varying doses of LTA, endorsing memory-like features in neutrophils.

CORM-2 prevents human gingival fibroblasts from lipoteichoic acid-induced VCAM-1 and ICAM-1 expression by inhibiting TLR2/MyD88/TRAF6/PI3K/Akt/ROS/NF-κB signaling pathway.

Periodontal diseases are prevalent worldwide. Lipoteichoic acid (LTA), a major component of gram-positive bacteria, may play a key role in periodontally inflammatory diseases. Carbon monoxide (CO) is a critical messenger in many biological processes. It can elicit various biological properties, especially anti-inflammatory effects. As the straight administration of CO remains difficult, CO-releasing molecules (CO-RMs) are emerging as promising alternatives. To explore the pharmacological actions and signaling pathways of CO battling LTA-induced periodontal inflammation, this study investigated the cytoprotective effects of CORM-2 against the adhesion of THP-1 monocytes to human gingival fibroblasts (HGFs) and the underlying molecular mechanism. After exposing HGFs to LTA with or without CORM-2 pretreatment, monocyte adhesion was determined. VCAM-1 and ICAM-1 expression in HGFs was measured by real-time PCR. To identify the signaling pathways of CO involved in the cytoprotective effects of CORM-2, HGFs underwent pharmacological or genetical interventions before LTA incubation. The expression and/or activity of possible regulatory molecules were determined. The release of pro-inflammatory cytokines, including IL-1ß, IL-6, and TNF-α, were measured using ELISA. The results showed that LTA increased cytokine production and upregulated VCAM-1 and ICAM-1 expression in HGFs, promoting monocyte adhesion. These events were dependent on TLR2/MyD88/TRAF6- and PI3K/Akt/NADPH oxidase/ROS-regulated NF-κB activation. CORM-2 inhibited LTA-induced inflammatory cascades in HGFs, in which CO seemed to be the hitman. To conclude, CO released from CORM-2 can prevent the LTA-stimulated HGFs from increasing VCAM-1 and ICAM-1 expression and promoting monocyte adhesion by inhibiting TLR2/MyD88/TRAF6 association and PI3K/Akt/NADPH oxidase/ROS signaling, both converge on the canonical NF-κB activation.

Lipoteichoic Acid from Lacticaseibacillus rhamnosus GG Modulates Dendritic Cells and T Cells in the Gut.

Lipoteichoic acid (LTA) from Gram-positive bacteria exerts different immune effects depending on the bacterial source from which it is isolated. Lacticaseibacillus rhamnosus GG LTA (LGG-LTA) oral administration reduces UVB-induced immunosuppression and skin tumor development in mice. In the present work, we evaluate the immunomodulatory effect exerted by LGG-LTA in dendritic cells (DC) and T cells, both in vitro and in the gut-associated lymphoid tissue (GALT). During cell culture, LTA-stimulated BMDC increased CD86 and MHC-II expression and secreted low levels of pro and anti-inflammatory cytokines. Moreover, LTA-treated BMDC increased T cell priming capacity, promoting the secretion of IL-17A. On the other hand, in orally LTA-treated mice, a decrease in mature DC (lamina propria and Peyer's patches) was observed. Concomitantly, an increase in IL-12p35 and IFN-γ transcription was presented (lamina propria and Peyer's Patches). Finally, an increase in the number of CD103+ DC was observed in Peyer's patches. Together, our data demonstrate that LGG-LTA activates DC and T cells. Moreover, we show that a Th1-biased immune response is triggered in vivo after oral LTA administration. These effects justify the oral LTA activity previously observed.

Carvacrol Suppresses Inflammatory Biomarkers Production by Lipoteichoic Acid- and Peptidoglycan-Stimulated Human Tonsil Epithelial Cells.

Pharyngitis is an inflammation of the pharynx caused by viral, bacterial, or non-infectious factors. In the present study, the anti-inflammatory efficacy of carvacrol was assessed using an in vitro model of streptococcal pharyngitis using human tonsil epithelial cells (HTonEpiCs) induced with Streptococcus pyogenes cell wall antigens. HTonEpiCs were stimulated by a mixture of lipoteichoic acid (LTA) and peptidoglycan (PGN) for 4 h followed by exposure to carvacrol for 20 h. Following exposure, interleukin (IL)-6, IL-8, human beta defensin-2 (HBD-2), epithelial-derived neutrophil-activating protein-78 (ENA-78), granulocyte chemotactic protein-2 (GCP-2), cyclooxygenase-2 (COX-2), tumor necrosis factor-alpha (TNF-α), and prostaglandin (PGE2) were measured by enzyme-linked immunosorbent assays (ELISA). The levels of pro-inflammatory cytokines, IL-6, IL-8, ENA-78, and GCP-2 were decreased in a carvacrol dose-dependent manner. The production of HBD-2 was significantly suppressed over 24 h carvacrol treatments. PGE2 and COX-2 levels in the cell suspensions were affected by carvacrol treatment. TNF-α was not detected. The cell viability of all the tested carvacrol concentrations was greater than 80%, with no morphological changes. The results suggest that carvacrol has anti-inflammatory properties, and carvacrol needs to be further assessed for potential clinical or healthcare applications to manage the pain associated with streptococcal pharyngitis.

Modulatory Effects of Fractalkine on Inflammatory Response and Iron Metabolism of Lipopolysaccharide and Lipoteichoic Acid-Activated THP-1 Macrophages.

Fractalkine (CX3CL1) acts as a chemokine as well as a regulator of iron metabolism. Fractalkine binds CX3CR1, the fractalkine receptor on the surface of monocytes/macrophages regulating different intracellular signalling pathways such as mitogen-activated protein kinase (MAPK), phospholipase C (PLC) and NFκB contributing to the production of pro-inflammatory cytokine synthesis, and the regulation of cell growth, differentiation, proliferation and metabolism. In this study, we focused on the modulatory effects of fractalkine on the immune response and on the iron metabolism of Escherichia coli and Pseudomonas aeruginosa lipopolysaccharides (LPS) and Staphylococcus aureus lipoteichoic acid (LTA) activated THP-1 cells to get a deeper insight into the role of soluble fractalkine in the regulation of the innate immune system. Pro-inflammatory cytokine secretions of the fractalkine-treated, LPS/LTA-treated, and co-treated THP-1 cells were determined using ELISArray and ELISA measurements. We analysed the protein expression levels of signalling molecules regulated by CX3CR1 as well as hepcidin, the major iron regulatory hormone, the iron transporters, the iron storage proteins and mitochondrial iron utilization. The results showed that fractalkine treatment alone did not affect the pro-inflammatory cytokine secretion, but it was proposed to act as a regulator of the iron metabolism of THP-1 cells. In the case of two different LPS and one type of LTA with fractalkine co-treatments, fractalkine was able to alter the levels of signalling proteins (NFκB, PSTAT3, Nrf2/Keap-1) regulating the expression of pro-inflammatory cytokines as well as hepcidin, and the iron storage and utilization of the THP-1 cells.

Virulence of Filifactor alocis lipoteichoic acid on human gingival fibroblast.

OBJECTIVES: The purpose of this study was to investigate virulence of lipoteichoic acid extracted from Filifactor alocis (F. alocis) through comparison of previously known bacterial virulence factors. DESIGN: F. alocis was cultured in columbia media including L-arginine and L-cysteine, and lipoteichoic acid (LTA) from F. alocis was purified using organic solvent and bead extraction. Human gingival fibroblasts (HGFs) were treated with the extracted LTA and other Gram-positive LTA or lipopolysaccharide of other periodontopathogens. The induction of cytokine expression was examined by real-time RT-PCR and ELISA, and the stimulated signaling pathway by the LTA was investigated by immunoblotting and various inhibitors. RESULTS: LTA induced expression of pro-inflammatory cytokines and Matrix-metalloprotein 2. Also, F. alocis LTA induced expression pro-inflammatory cytokines similar to Porphyromonas gingivalis lipopolysaccharide. The LTA activated NF-κB and MAP kinase pathway. Furthermore, the induction of TNF-α, IL-6, IL-8, and MMP-2 expression by F. alocis LTA was reduced by the inhibitor of NF-κB, ERK, JNK, and p38 pathway. CONCLUSIONS: LTA of F. alocis, a bacterium recently detected in periodontal patients, may play an important role in inducing periodontitis by induction of expression of pro-inflammatory cytokines.

Insight into the molecular basis of substrate recognition by the wall teichoic acid glycosyltransferase TagA.

Wall teichoic acid (WTA) polymers are covalently affixed to the Gram-positive bacterial cell wall and have important functions in cell elongation, cell morphology, biofilm formation, and ß-lactam antibiotic resistance. The first committed step in WTA biosynthesis is catalyzed by the TagA glycosyltransferase (also called TarA), a peripheral membrane protein that produces the conserved linkage unit, which joins WTA to the cell wall peptidoglycan. TagA contains a conserved GT26 core domain followed by a C-terminal polypeptide tail that is important for catalysis and membrane binding. Here, we report the crystal structure of the Thermoanaerobacter italicus TagA enzyme bound to UDP-N-acetyl-d-mannosamine, revealing the molecular basis of substrate binding. Native MS experiments support the model that only monomeric TagA is enzymatically active and that it is stabilized by membrane binding. Molecular dynamics simulations and enzyme activity measurements indicate that the C-terminal polypeptide tail facilitates catalysis by encapsulating the UDP-N-acetyl-d-mannosamine substrate, presenting three highly conserved arginine residues to the active site that are important for catalysis (R214, R221, and R224). From these data, we present a mechanistic model of catalysis that ascribes functions for these residues. This work could facilitate the development of new antimicrobial compounds that disrupt WTA biosynthesis in pathogenic bacteria.

Chemomechanical preparation influences the microbial community and the levels of LPS, LTA and cytokines in combined endodontic-periodontal lesions: A clinical study.

BACKGROUND: This study was conducted to compare the microbiomes, the levels of lipopolysaccharides (LPS), lipoteichoic acid (LTA), and cytokines (interleukin [IL]-1ß and tumor necrosis factor-alpha [TNF-α]), before and after chemomechanical preparation (CMP) of the root canals (RC) and their associated periodontal pockets (PP) in teeth with combined EPL. MATERIALS: Samples were taken from 10 RC and PP, before and after CMP. The microbiomes (next-generation sequencing, V3-V4 hypervariable region of the 16S rRNA gene), microbiome diversity (bioinformatics analyses), LPS (limulus amebocyte lysate), LTA, IL-1ß, and TNF-α (ELISA) were evaluated. A statistical analysis was performed with significance level set at 5%. RESULTS: The most abundant phyla in both sites were Firmicutes and Proteobacteria. Comparative studies of bacterial genera species revealed that some increased and others decreased after CMP at both sites. A 3% reduction in Gram-negative bacteria (RC) and a 4% increase in Gram-positive bacteria (PP) were detected. LPS levels were 4.4 times higher in PP than in the RC. LTA was detected in all samples investigated. Higher levels of IL-1ß and TNF-α were detected in both sites at baseline. After CMP, LPS, LTA, IL-1ß and TNF-α were reduced in both sites. CONCLUSION: The microbial community in the RC and PP in teeth with combined EPL indicated a similarity between both sites. CMP effectively reduced the microbial load and the LPS levels from teeth with EPL, and consequently diminished the cytokine levels. The reduction in LTA levels in the RC and PP proved challenging.

ACLY Nuclear Translocation in Human Macrophages Drives Proinflammatory Gene Expression by NF-κB Acetylation.

Macrophage stimulation by pathogen-associated molecular patterns (PAMPs) like lipopolysaccharide (LPS) or lipoteichoic acid (LTA) drives a proinflammatory phenotype and induces a metabolic reprogramming to sustain the cell's function. Nevertheless, the relationship between metabolic shifts and gene expression remains poorly explored. In this context, the metabolic enzyme ATP citrate lyase (ACLY), the producer of citrate-derived acetyl-coenzyme A (CoA), plays a critical role in supporting a proinflammatory response. Through immunocytochemistry and cytosol-nucleus fractionation, we found a short-term ACLY nuclear translocation. Protein immunoprecipitation unveiled the role of nuclear ACLY in NF-κB acetylation and in turn its full activation in human PBMC-derived macrophages. Notably, sepsis in the early hyperinflammatory phase triggers ACLY-mediated NF-κB acetylation. The ACLY/NF-κB axis increases the expression levels of proinflammatory genes, including SLC25A1-which encodes the mitochondrial citrate carrier-and ACLY, thus promoting the existence of a proinflammatory loop involving SLC25A1 and ACLY genes.

Gut-liver axis-mediated mechanism of liver cancer: A special focus on the role of gut microbiota.

Gut microbiota and the mammalian host share a symbiotic relationship, in which the host provides a suitable ecosystem for the gut bacteria to digest indigestible nutrients and produce useful metabolites. Although gut microbiota primarily reside in and influence the intestine, they also regulate liver function via absorption and subsequent transfer of microbial components and metabolites through the portal vein to the liver. Due to this transfer, the liver may be continuously exposed to gut-derived metabolites and components. For example, short-chain fatty acids (SCFA) produced by gut microbiota, through the fermentation of dietary fiber, can suppress inflammation via regulatory T cell induction through SCFA-induced epigenetic mechanisms. Additionally, secondary bile acids (BA), such as deoxycholic acid, produced by gut bacteria through the 7α-dehydroxylation of primary BAs, are thought to induce DNA damage and contribute to the remodeling of tumor microenvironments. Other substances that are also thought to influence liver function include lipopolysaccharides (components of the outer membrane of gram-negative bacteria) and lipoteichoic acid (cell wall component of Gram-positive bacteria), which are ligands of innate immune receptors, Toll-like receptor-4, and Toll-like receptor-2, respectively, through which inflammatory signaling is elicited. In this review, we focus on the role of gut microbiota in the liver microenvironment, describing the anatomy of the gut-liver axis, the role of gut microbial metabolites, and the relationships that exist between gut microbiota and liver diseases, including liver cancer.