A novel fatty acid analogue triggers CD36-GPR120 interaction and exerts anti-inflammatory action in endotoxemia.

Inflammation is a mediator of a number of chronic pathologies. We synthesized the diethyl (9Z,12Z)-octadeca-9,12-dien-1-ylphosphonate, called NKS3, which decreased lipopolysaccharide (LPS)-induced mRNA upregulation of proinflammatory cytokines (IL-1ß, IL-6 and TNF-α) not only in primary intraperitoneal and lung alveolar macrophages, but also in freshly isolated mice lung slices. The in-silico studies suggested that NKS3, being CD36 agonist, will bind to GPR120. Co-immunoprecipitation and proximity ligation assays demonstrated that NKS3 induced protein-protein interaction of CD36 with GPR120in RAW 264.7 macrophage cell line. Furthermore, NKS3, via GPR120, decreased LPS-induced activation of TAB1/TAK1/JNK pathway and the LPS-induced mRNA expression of inflammatory markers in RAW 264.7 cells. In the acute lung injury model, NKS3 decreased lung fibrosis and inflammatory cytokines (IL-1ß, IL-6 and TNF-α) and nitric oxide (NO) production in broncho-alveolar lavage fluid. NKS3 exerted a protective effect on LPS-induced remodeling of kidney and liver, and reduced circulating IL-1ß, IL-6 and TNF-α concentrations. In a septic shock model, NKS3 gavage decreased significantly the LPS-induced mortality in mice. In the last, NKS3 decreased neuroinflammation in diet-induced obese mice. Altogether, these results suggest that NKS3 is a novel anti-inflammatory agent that could be used, in the future, for the treatment of inflammation-associated pathologies.

The protective effects of naringenin, a citrus flavonoid, non-complexed or complexed with hydroxypropyl-ß-cyclodextrin against multiorgan damage caused by neonatal endotoxemia.

BACKGROUND: Endotoxemia is a severe and dangerous clinical syndrome that results in elevated morbidity, especially in intensive care units. Neonates are particularly susceptible to endotoxemia due to their immature immune systems. There are few effective treatments for neonatal endotoxemia. One group of compounds with potential in the treatment of neonatal inflammatory diseases such as endotoxemia is the flavonoids, mainly due to their antioxidant and anti-inflammatory properties. Among these, naringenin (NGN) is a citrus flavonoid which has already been reported to have anti-inflammatory, antioxidant, anti-nociceptive and anti-cancer effects. Unfortunately, its clinical application is limited by its low solubility and bioavailability. However, cyclodextrins (CDs) have been widely used to improve the solubility of nonpolar drugs and enhance the bioavailability of these natural products. OBJECTIVE: We, therefore, aimed to investigate the effects of NGN non-complexed and complexed with hydroxypropyl-ß-cyclodextrin (HPßCD) on neonatal endotoxemia injuries in a rodent model and describe the probable molecular mechanisms involved in NGN activities. METHOD: We used exposure to a bacterial lipopolysaccharide (LPS) to induce neonatal endotoxemia in the mice. RESULTS: It was found that NGN (100 mg/kg i.p.) exposure during the neonatal period reduced leukocyte migration and decreased pro-inflammatory cytokine (TNF-α, IL-1ß and IL-6) levels in the lungs, heart, kidneys or cerebral cortex. In addition, NGN upregulated IL-10 production in the lungs and kidneys of neonate mice. The administration of NGN also enhanced antioxidant enzyme catalase and SOD activity, reduced lipid peroxidation and protein carbonylation and increased the reduced sulfhydryl groups in an organ-dependent manner, attenuating the oxidative damage caused by LPS exposure. NGN decreased ERK1/2, p38MAPK and COX-2 activation in the lungs of neonate mice. Moreover, NGN complexed with HPßCD was able to increase the animal survival rate. CONCLUSION: NGN attenuated inflammatory and oxidative damage in the lungs, heart and kidneys caused by neonatal endotoxemia through the MAPK signaling pathways regulation. Our results show that NGN has beneficial effects against neonatal endotoxemia and could be useful in the treatment of neonatal inflammatory injuries.

Galgravin Isolated from Piper kadsura Ameliorates Lipopolysaccharide (LPS)-Induced Endotoxemia in Mice.

Sepsis results from uncontrolled inflammation, characterized by cytokine storm and immunoparalysis. To assess whether galgravin, a natural lignan isolated from Piper kadsura, can be used to treat sepsis, models of bacterial lipopolysaccharide (LPS)-activated macrophages and LPS-induced endotoxemia mice were used. Galgravin suppressed NF-κB activation in LPS-activated RAW 264.7 macrophages without causing significant cytotoxicity, in which proinflammatory molecules like TNF-α, IL-6, iNOS, and COX-2 were downregulated. In addition, the expression of TNF-α and IL-6 was also suppressed by galgravin in LPS-activated murine bone marrow-derived macrophages. Moreover, galgravin significantly downregulated the mRNA expression of TNF-α, IL-6, and iNOS in the lungs and decreased TNF-α and IL-6 in the serum and IL-6 in the bronchoalveolar lavage fluid of LPS-challenged mice. The COX-2 expression in tissues, including the lung, liver, and kidney, as well as the lung alveolar hemorrhage, was also reduced by galgravin. The present study reveals the anti-inflammatory effects of galgravin in mouse models and implies its potential application in inflammation diseases.

Guggulsterone protects against lipopolysaccharide-induced inflammation and lethal endotoxemia via heme oxygenase-1.

Guggulsterone (GS) is a phytosterol used to treat inflammatory diseases. Although many studies have examined the anti-inflammatory activities of GS, the detailed mechanisms of GS in lipopolysaccharide (LPS)-induced inflammation and endotoxemia have not yet been examined. Therefore, we investigated the anti-inflammatory effects of GS on LPS-induced inflammation. In murine peritoneal macrophages, the anti-inflammatory activity of GS was primarily mediated by heme oxygenase-1 (HO-1) induction. HO-1 induction by GS was mediated by GSH depletion and reactive oxygen species (ROS) production. The ROS generated by GS caused the phosphorylation of GSK3ß (ser9/21) and p38, leading to the translocation of nuclear factor erythroid-related factor 2 (Nrf2), which ultimately induced HO-1. In addition, GS pretreatment significantly inhibited inducible nitric oxide synthase (iNOS), iNOS-derived NO, and COX-2 protein and mRNA expression, and production of COX-derived prostaglandin PGE2, interleukin (IL)-1ß, IL-6, and tumor necrosis factor-α (TNF-α). In a mouse model of endotoxemia, GS treatment prolonged survival and inhibited the expression of inflammatory mediators, including IL-1ß, IL-6, and TNF-α. GS treatment also inhibited LPS-induced liver injury. These results suggest that GS-induced HO-1 could exert anti-inflammatory effects via ROS-dependent GSK (ser21/9)-p38 phosphorylation and nuclear translocation of Nrf2.

Protective effect of hydrangenol on lipopolysaccharide-induced endotoxemia by suppressing intestinal inflammation.

Hydrangenol, a dihydroisocoumarin, isolated from the leaves of Hydrangea serrata, possesses anti-inflammatory, anti-obesity, and anti-photoaging activities. In this study, we investigated the protective effects of hydrangenol (HG) against lipopolysaccharide (LPS)-induced endotoxemia and elucidated the underlying molecular mechanisms of action in C57BL/6 mice. Oral administration of HG (20 or 40 mg/kg) significantly restored the survival rate and population of macrophages, T helper cells (CD3+/CD4+), and Th17 cells (CD3+/CD4+/CCR6+) in the spleens of mice with LPS-induced endotoxemia. HG suppressed the expression of pro-inflammatory cytokines such as tumor necrosis factor-α (TNF-α), interleukin (IL)-6, IL-1ß, and Interferon (IFN)-γ and the mRNA and protein expressions of inducible NO synthase (iNOS) and cyclooxygenase-2 (COX-2) in the intestine and lung of LPS-treated mice. Molecular data showed that HG ameliorated the activation of nuclear factor kappa B (NF-κB) p65, signal transducers and activators of transcription 3 (STAT3), and c-Fos and c-Jun (AP-1 subunits) via the myeloid differentiation primary response 88 (MyD88) dependent toll-like receptor 4 (TLR4) signaling pathway in the LPS-treated mouse intestines. HG treatment caused the recovery of LPS-induced impaired tight junction (occludin and claudin-2) protein and mRNA expressions. Furthermore, HG improved LPS-induced gut dysbiosis in mice. Taken together, our results suggest that HG protects against LPS-induced endotoxemia by restoring immune cells and the capacity of the intestinal barrier, reducing intestinal inflammation, and improving the composition of the gut microbiota.

Effect of mitoTEMPO on Redox Reactions in Different Body Compartments upon Endotoxemia in Rats.

Mitochondrial ROS (mitoROS) control many reactions in cells. Biological effects of mitoROS in vivo can be investigated by modulation via mitochondria-targeted antioxidants (mtAOX, mitoTEMPO). The aim of this study was to determine how mitoROS influence redox reactions in different body compartments in a rat model of endotoxemia. We induced inflammatory response by lipopolysaccharide (LPS) injection and analyzed effects of mitoTEMPO in blood, abdominal cavity, bronchoalveolar space, and liver tissue. MitoTEMPO decreased the liver damage marker aspartate aminotransferase; however, it neither influenced the release of cytokines (e.g., tumor necrosis factor, IL-4) nor decreased ROS generation by immune cells in the compartments examined. In contrast, ex vivo mitoTEMPO treatment substantially reduced ROS generation. Examination of liver tissue revealed several redox paramagnetic centers sensitive to in vivo LPS and mitoTEMPO treatment and high levels of nitric oxide (NO) in response to LPS. NO levels in blood were lower than in liver, and were decreased by in vivo mitoTEMPO treatment. Our data suggest that (i) inflammatory mediators are not likely to directly contribute to ROS-mediated liver damage and (ii) mitoTEMPO is more likely to affect the redox status of liver cells reflected in a redox change of paramagnetic molecules. Further studies are necessary to understand these mechanisms.

Protective effects of an anti-4-HNE monoclonal antibody against liver injury and lethality of endotoxemia in mice.

4-hydroxy-2-nonenal (4-HNE) is a lipid peroxidation product that is known to be elevated during oxidative stress. During systemic inflammation and endotoxemia, plasma levels of 4-HNE are elevated in response to lipopolysaccharide (LPS) stimulation. 4-HNE is a highly reactive molecule due to its generation of both Schiff bases and Michael adducts with proteins, which may result in modulation of inflammatory signaling pathways. In this study, we report the production of a 4-HNE adduct-specific monoclonal antibody (mAb) and the effectiveness of the intravenous injection of this mAb (1 mg/kg) in ameliorating LPS (10 mg/kg, i.v.)-induced endotoxemia and liver injury in mice. Endotoxic lethality in control mAb-treated group was suppressed by the administration of anti-4-HNE mAb (75 vs. 27%). After LPS injection, we observed a significant increase in the plasma levels of AST, ALT, IL-6, TNF-α and MCP-1, and elevated expressions of IL-6, IL-10 and TNF-α in the liver. All these elevations were inhibited by anti-4-HNE mAb treatment. As to the underlining mechanism, anti-4-HNE mAb inhibited the elevation of plasma high mobility group box-1 (HMGB1) levels, the translocation and release of HMGB1 in the liver and the formation of 4-HNE adducts themselves, suggesting a functional role of extracellular 4-HNE adducts in hypercytokinemia and liver injury associated with HMGB1 mobilization. In summary, this study reveals a novel therapeutic application of anti-4-HNE mAb for endotoxemia.

Nicaraven protects against endotoxemia-induced inflammation and organ injury through modulation of AMPK/Sirt1 signaling in macrophages.

Endotoxemia is a disease characterized by systemic inflammatory responses and organ injury caused by lipopolysaccharide (LPS) infection, with high mortality. Nicaraven (AVS), a potent hydroxyl radical scavenger, has been proven to regulate the inflammatory response in tumors. To investigate the protective effects and mechanisms of AVS in endotoxemia, mice were injected intraperitoneally with LPS to induce endotoxemia. AVS treatment significantly decreased the levels of pro-inflammatory cytokines in the serum, reduced neutrophil infiltration, attenuated multiple organ injury, and increased the survival rate in LPS-challenged mice. In the LPS-induced inflammatory model of macrophages, AVS inhibited macrophage activation, suppressed nitric oxide (NO) production, and inhibited the expression and secretion of pro-inflammatory cytokines. Mechanistically, AVS treatment up-regulated silence information regulator transcript-1 (Sirt1) expression in a time- and dose-dependent manner. AVS treatment activated the AMP-dependent protein kinase (AMPK)/Sirt1 signaling pathway and suppressed the activation of nuclear factor kappa B (NF-κB) in macrophages exposed to LPS. However, the anti-inflammatory effects of AVS could be reversed by the AMPK, the Sirt1 inhibitor, or the histone deacetylase inhibitor. We confirmed that the AMPK inhibitor inhibited AVS-mediated AMPK/Sirt1 activation and NF-κB p65 acetylation. These results suggested that AVS alleviated endotoxemia by activating the AMPK/Sirt1 signaling pathway in macrophages.

Protective Effect of Electroacupuncture on the Barrier Function of Intestinal Injury in Endotoxemia through HO-1/PINK1 Pathway-Mediated Mitochondrial Dynamics Regulation.

Background and Aims: Endotoxemia (ET) is a common critical illness in patients receiving intensive care and is associated with high mortality and prolonged hospital stay. The intestinal epithelial cell dysfunction is regarded as the "engine" of deteriorated ET. Although electroacupuncture (EA) can mitigate endotoxin-induced intestinal epithelial cell dysfunction in ET, the mechanism through which EA improves endotoxin-induced intestinal injury for preventing ET deterioration needs further investigation. Methods: An in vivo ET model was developed by injecting lipopolysaccharide (LPS) in wild-type and PINK1-knockout mice. An in vitro model was also established by incubating epithelial cells in the serum samples obtained from both groups of mice. Hemin and zinc protoporphyrin IX (ZnPP) were applied to activate or inhibit heme oxygenase 1 (HO-1) production. EA treatment was performed for 30 min consecutively for 5 days before LPS injection, and on the day of the experiment, EA was performed throughout the process. Samples were harvested at 6 h after LPS induction for analyzing tissue injury, oxidative stress, ATP production, activity of diamine oxidase (DAO), and changes in the levels of HO-1, PTEN-induced putative kinase 1 (PINK1), mitochondrial fusion and fission marker gene, caspase-1, and interleukin 1 beta (IL-1ß). Results: In the wild-type models (both in vivo and vitro), EA alleviated LPS-induced intestinal injury and mitochondrial dysfunction, as indicated by decreased reactive oxygen species (ROS) production and oxygen consumption rate (OCR) and reduced levels of mitochondrial fission proteins. EA treatment also boosted histopathological morphology, ATP levels, DAO activity, and levels of mitochondrial fusion proteins in vivo and vitro. The effect of EA was enhanced by hemin but suppressed by Znpp. However, EA + AP, Znpp, or hemin had no effects on the LPS-induced, PINK1-knocked out mouse models. Conclusion: EA may improve the HO-1/PINK1 pathway-mediated mitochondrial dynamic balance to protect the intestinal barrier in patients with ET.

Qingdu decoction can reduce LPS induced ACLF endotoxemia by regulating microRNA-34c/MAZ/TJs and microRNA-122a/Zonulin/EGFR signal pathway.

ETHNOPHARMACOLOGICAL RELEVANCE: Qingdu Decoction (QDT) is a traditional Chinese medicine (TCM) that was derived from Xiaochengqi Decoction, a famous decoction documented in the book of Treatise on Exogenous Febrile Disease in the Eastern Han Dynasty. According to our years of clinical application, QDT showed satisfactory efficacy in the treatment of endotoxemia in acute-on-chronic liver failure (ACLF). However, the underlying molecular mechanisms remain largely unknown. AIM OF STUDY: In this study, we aimed to systematically evaluate the intervention effect of QDT on endotoxemia in rats and further clarify its potential regulatory mechanism. MATERIALS AND METHODS: The rat model of ACLF endotoxemia was induced by TAA and LPS + D-Gal. Then the rats were treated with clinical doses of QDT and lactulose. The rats were divided into four groups: CG, MG, QG and LG. The target microRNA was screened by high-throughput sequencing. The rat weight, liver index, hepatointestinal phenotype, serum biochemical indexes, mast cell activity, and hepatointestinal histopathology were used to evaluate the intervention effect. Western blot analysis was used to detect the expression levels of MAZ and its downstream genes ZO-1 and Occludin, and the expression levels of Zonulin and its downstream gene EGFR in colon. Finally, the expression of the miR-34c, MAZ, ZO-1, Occludin, miR-122a, Zonulin, and EGFR in colon was detected by qRT-PCR to further confirm the mechanism of the miR-34c/MAZ/TJs pathway and the miR-122a/Zonulin/EGFR pathway. RESULTS: The rat weight, liver index, liver and colon phenotype, and serum biochemical indexes showed that QDT could significantly reduce liver and intestine injury and inhibit the progress of ACLF and endotoxemia. Toluidine blue staining and cytokine indexes showed that QDT could inhibit the activity of MCs and reduce the release of inflammatory factors. Mechanistically, QDT can inhibit the activity of MCs, activate miR-34c/MAZ/TJs pathway and miR-122a/Zonulin/EGFR pathway in colon, promote the recovery of intestinal barrier homeostasis, reduce and restore the damage of endotoxemia. CONCLUSION: Our results suggested that QDT can significantly reduce rat ACLF endotoxemia by regulating the miR-34c/MAZ/TJs pathway and the miR-122a/Zonulin/EGFR pathway in colon.

The Anti-Inflammatory Effect of Carrageenan/Echinochrom Complex at Experimental Endotoxemia.

The anti-inflammatory effects of the CRG/Ech complex in LPS-induced endotoxemia were investigated in vivo in mice and in vitro in LPS-stimulated RAW 264.7 cells and peritoneal macrophages. The results indicated that the CRG/Ech complex suppressed the LPS-induced inflammatory response by reducing the production of ROS and NO in the macrophages. Furthermore, the in vivo experiment indicated that the CRG/Ech complex minimized disorders of the physiological and metabolic processes in mice subjected to LPS intoxication and reduced the levels of proinflammatory cytokines in the mouse serum. The preventive administration of the CRG/Ech complex to mice prevented endotoxin-induced damage in the mouse model of endotoxemia, increased the mice's resistance to LPS, and prevented increases in the levels of proinflammatory cytokines (TNFα). In this work, we showed by the molecular docking that Ech interacted with carrageenan, and that H-donor and H-acceptor bonds are involved in the formation of the complex.

Pinostrobin ameliorates lipopolysaccharide (LPS)-induced inflammation and endotoxemia by inhibiting LPS binding to the TLR4/MD2 complex.

Pinostrobin is a natural flavonoid with valuable pharmacological properties, including anti-cancer, anti-viral, and anti-oxidant activities. However, the anti-inflammatory effects of pinostrobin have not been well studied. In this study, we investigated whether pinostrobin attenuates lipopolysaccharide (LPS)-induced inflammation and endotoxemia. Additionally, the target molecule of pinostrobin was identified through molecular docking simulation. Pinostrobin decreased LPS-induced nitric oxide (NO) and prostaglandin E2 production, and reduced the expression of inducible NO synthase and cyclooxygenase-2. Furthermore, pinostrobin inhibited the production of proinflammatory cytokines, including interleukin-12 and tumor necrosis factor-α in LPS-stimulated RAW 264.7 macrophages accompanied by inhibiting nuclear translocation of nuclear factor-κB. The anti-inflammatory effect of pinostrobin was further confirmed in LPS-microinjected zebrafish larvae by diminishing the recruitment of macrophages and neutrophils, and proinflammatory gene expression. Moreover, LPS-microinjected zebrafish larvae showed a decrease in heart rate and an increase in mortality and abnormalities. However, pinostrobin significantly attenuated these adverse effects. Molecular docking showed that pinostrobin fits into myeloid differentiation factor (MD2) and Toll-like receptor 4 (TLR4) with no traditional hydrogen bonds (pose 1). The 2D ligand interaction diagram showed that pinostrobin forms a carbon hydrogen bond with LYS89 in MD2 and many non-covalent interactions, including π-alkyl or alkyl and van der Waals interactions, indicating that pinostrobin hinders LPS binding between MD2 and TLR4 and consequently inhibits TLR4/MD2-mediated inflammatory responses. These data suggest that pinostrobin attenuates LPS-induced inflammation and endotoxemia by binding to the TLR4/MD2 complex.

Central α7 and α4ß2 nicotinic acetylcholine receptors offset arterial baroreceptor dysfunction in endotoxic rats.

Cardiac autonomic neuropathy is a prominent feature of endotoxemia. Given the defensive role of the cholinergic pathway in inflammation, we assessed the roles of central homomeric α7 and heteromeric α4ß2 nAChRs in arterial baroreceptor dysfunction caused by endotoxemia in rats. Endotoxemia was induced by i.v. administration of lipopolysaccharides (LPS, 10 mg/kg), and baroreflex activity was measured by the vasoactive method, which assesses reflex chronotropic responses to increments (phenylephrine, PE) or decrements (sodium nitroprusside, SNP) in blood pressure. Shifts caused by LPS in PE/SNP baroreflex curves and associated decreases in baroreflex sensitivity (BRS) were dose-dependently reversed by nicotine (25-100 µg/kg, i.v.). The nicotine effect disappeared after intracisternal administration of methyllycaconitine (MLA) or dihydro-ß-erythroidine (DHßE), selective blockers of α7 and α4ß2 receptors, respectively. The advantageous effect of nicotine on BRSPE was replicated in rats treated with PHA-543613 (α7-nAChR agonist) or 5-iodo-A-85380 (5IA, α4ß2-nAChRs agonist) in dose-dependent fashions. Conversely, the depressed BRSSNP of endotoxic rats was improved after combined, but not individual, treatments with PHA and 5IA. Central α7 and α4ß2 nAChR activation underlies the nicotine counteraction of arterial baroreflex dysfunction induced by endotoxemia. Moreover, the contribution of these receptors depends on the nature of the reflex chronotropic response (bradycardia vs. tachycardia).

The protective effect of muscimol against systemic inflammatory response in endotoxemic mice is independent of GABAergic and cholinergic receptors.

Systemic inflammatory response syndrome plays an important role in the development of sepsis. GABAergic and cholinergic pathways activation are considered important for inflammatory response regulation. Tumor necrosis factor (TNF)-α, interleukin (IL)-1ß, IL-12, IL-10, as well as inducible nitric oxide synthase (iNOS)-derived nitric oxide (NO) are important inflammatory mediators involved in the pathogenesis of sepsis. Muscimol, an active compound from the mushroom Amanita muscaria (L.) Lam., is a potent GABAA agonist, inhibits inflammatory response via activating GABAA receptor and vagus nerve. However, the effect of muscimol on lipopolysaccharide (LPS)-induced systemic inflammatory response is still unclear. Therefore, we studied the effects of muscimol on systemic inflammatory response and survival rate in endotoxemic mice. Mice endotoxemia was induced by LPS. Muscimol was given to mice or RAW264.7 cells 30 min before LPS (10 mg/kg, i.p., or 10 ng/mL, respectively). Mice received GABAergic and cholinergic receptor antagonists 30 min before muscimol and LPS. Muscimol decreased TNF-α, IL-1ß, IL-12, iNOS-derived NO, and increased IL-10 levels and survival rate after LPS treatment. Muscimol significantly decreased nuclear factor kappa B (NF-κB) activity, increased IκB expression, and decreased pIKK expression in LPS-treated RAW264.7 cells. GABAergic and cholinergic antagonists failed to reverse muscimol's protection in LPS-treated mice. In conclusion, muscimol protected against systemic inflammatory response in endotoxemic mice may be partially independent of GABAergic and cholinergic receptors.

N-Oleoyl dopamine induces IL-10 via central nervous system TRPV1 and improves endotoxemia and sepsis outcomes.

BACKGROUND: The transient receptor potential vanilloid 1 (TRPV1) participates in thermosensation and inflammatory pain, but its immunomodulatory mechanisms remain enigmatic. N-Oleoyl dopamine (OLDA), an endovanilloid and endocannabinoid, is a TRPV1 agonist that is produced in the central nervous system and the peripheral nervous system. We studied the anti-inflammatory effects and TRPV1-dependent mechanisms of OLDA in models of inflammation and sepsis. METHODS: Mice were challenged intratracheally or intravenously with LPS, or intratracheally with S. aureus to induce pneumonia and sepsis, and then were treated intravenously with OLDA. Endpoints included plasma cytokines, leukocyte activation marker expression, mouse sepsis scores, lung histopathology, and bacterial counts. The role of TRPV1 in the effects of OLDA was determined using Trpv1-/- mice, and mice with TRPV1 knockdown pan-neuronally, in peripheral nervous system neurons, or in myeloid cells. Circulating monocytes/macrophages were depleted using clodronate to determine their role in the anti-inflammatory effects of OLDA in endotoxemic mice. Levels of exogenous OLDA, and of endovanilloids and endocannabinoids, at baseline and in endotoxemic mice, were determined by LC-MS/MS. RESULTS: OLDA administration caused an early anti-inflammatory response in endotoxemic and septic mice with high serum levels of IL-10 and decreased levels of pro-inflammatory cytokines. OLDA also reduced lung injury and improved mouse sepsis scores. Blood and lung bacterial counts were comparable between OLDA- and carrier-treated mice with S. aureus pneumonia. OLDA's effects were reversed in mice with pan-neuronal TRPV1 knockdown, but not with TRPV1 knockdown in peripheral nervous system neurons or myeloid cells. Depletion of monocytes/macrophages reversed the IL-10 upregulation by OLDA in endotoxemic mice. Brain and blood levels of endovanilloids and endocannabinoids were increased in endotoxemic mice. CONCLUSIONS: OLDA has strong anti-inflammatory actions in mice with endotoxemia or S. aureus pneumonia. Prior studies focused on the role of peripheral nervous system TRPV1 in modulating inflammation and pneumonia. Our results suggest that TRPV1-expressing central nervous system neurons also regulate inflammatory responses to endotoxemia and infection. Our study reveals a neuro-immune reflex that during acute inflammation is engaged proximally by OLDA acting on neuronal TRPV1, and through a multicellular network that requires circulating monocytes/macrophages, leads to the systemic production of IL-10.

Effects of pre-treatment with inulin on the kidney in lipopolysaccharide-induced endotoxemia in rats.

This study was aimed to evaluate the effects of inulin used as prebiotic on the kidney in lipopolysaccharide (LPS)-induced endotoxemia model. Wistar Albino rats were divided into four groups: Control group, LPS (endotoxemia) group, Inulin + LPS group in which LPS (1.5 mg/kg, E. coli, Serotype 0111: B4) was treated after inulin (500 mg/kg) given by gavage for 21 days and Inulin group. The animals were sacrificed 24 h after the last LPS injection. Kidney samples were taken for biochemical and immunohistochemical analyses. Total antioxidant status (TAS), total oxidant status (TOS), oxidative stress index (OSI), malondialdehyde (MDA) and myeloperoxidase (MPO) values were determined. In addition, kidney sections were stained for inducible nitric oxide synthase (iNOS), tumor necrosis factor (TNF)-α and interleukine-6 (IL-6) expression, and leukocyte infiltration. LPS caused oxidative stress and inflammation. Inulin administration could prevent oxidative stress and lipid peroxidation. Moreover, inulin decreased iNOS, TNF-α and IL-6 expression. However, it did not change the distribution of leukocytes in kidney tissues. These results suggest to promising benefits of inulin as prebiotic in reducing the effects of endotoxemia. Further studies should be conducted to evaluate the capacity of prebiotics in endotoxemia.

Hepatic pannexin-1 mediates ST2+ regulatory T cells promoting resolution of inflammation in lipopolysaccharide-induced endotoxemia.

Sepsis remains the most lethal infectious disease and substantially impairs patient prognosis after liver transplantation (LT). Our previous study reported a role of the pannexin 1 (PANX1)-interleukin-33 (IL-33) axis in activating innate immunity to protect against methicillin-resistant Staphylococcus aureus infection; however, the role of PANX1 in regulating adaptive immunity in sepsis and the underlying mechanism are unclear. In this study, we examined the role of the PANX1-IL-33 axis in protecting against sepsis caused by a gram-negative bacterial infection in an independent LT cohort. Next, in animal studies, we assessed the immunological state of Panx1-/- mice with lipopolysaccharide (LPS)-induced endotoxemia and then focused on the cytokine storm and regulatory T cells (Tregs), which are crucial for the resolution of inflammation. To generate liver-specific Panx1-deficient mice and mimic clinical LT procedures, a mouse LT model was established. We demonstrated that hepatic PANX1 deficiency exacerbated LPS-induced endotoxemia and dysregulated the immune response in the mouse LT model. In hepatocytes, we confirmed that PANX1 positively regulated IL-33 synthesis after LPS administration. We showed that the adenosine triphosphate-P2X7 pathway regulated the hepatic PANX1-IL-33 axis during endotoxemia in vitro and in vivo. Recombinant IL-33 treatment rescued LPS-induced endotoxemia by increasing the numbers of liver-infiltrating ST2+ Tregs and attenuating the cytokine storm in hepatic PANX1-deficient mice. In conclusion, our findings revealed that the hepatic PANX1-IL-33 axis protects against endotoxemia and liver injury by targeting ST2+ Tregs and promoting the early resolution of hyperinflammation.

Resolvin D5 (RvD5) Reduces Renal Damage Caused by LPS Endotoxemia in Female Mice.

In self-revolving gram-negative Escherichia coli infection, Resolvin D5 (RvD5) was found to enhance bacteria phagocytosis and reduce the production of inflammatory mediators, contributing to the resolution of infection. LPS (lipopolysaccharide) is a gram-negative bacterial structure product which activates the immune system and, at high doses, leads to endotoxemia. To our knowledge, the effect of RvD5 against LPS endotoxemia has not been investigated to date. Female Swiss mice received an i.p. treatment with RvD5 (0.1, 1 or 10 ng/animal). After 1 h, they were stimulated with LPS (10 mg/kg, i.v.), and samples were collected after additional 6 h. The resulting data demonstrated that RvD5 protected the kidneys (urea and creatinine serum levels) from tissue injury. These effects were related to an improvement in histopathological parameters and a reduction of enzymatic markers of leukocyte infiltration, pro-inflammatory cytokine (IL-1ß, TNF-α, and IL-6) production, and oxidative stress. Antioxidant markers were also increased by RvD5, but IL-10 (an anti-inflammatory cytokine) levels were unaltered. We also observed that RvD5 reduced the infiltration of CD45+ hematopoietic cells into the kidneys, reduced the activation of NFκB and promoted the Nrf2 pathway by reducing Keap-1 levels. Our data indicate that RvD5 may be a therapeutic possibility to reduce kidney lesions in LPS endotoxemia.

Potentilla discolor ameliorates LPS-induced inflammatory responses through suppressing NF-κB and AP-1 pathways.

Potentilla discolor Bunge (PD) is a traditional Chinese medicine which has been widely used for the treatment of various inflammatory diseases (e.g., diarrhea, fever and furuncle). However, few studies focused on its effect on classical inflammation. This study aimed to investigate the anti-inflammatory effect and potential mechanism of the ethanol extract of the whole herbs of PD (EPD) in lipopolysaccharide (LPS)-induced inflammatory models. The obtained results showed that EPD decreased supernatant NO, tumor necrosis factor-α (TNF-α) and monocyte chemoattractant protein-1 (MCP-1) in LPS-activated RAW264.7 cells and mouse peritoneal macrophages. Moreover, its effect on NO was attributed to the suppression of iNOS expression rather than its activity. At the transcriptional level, EPD suppressed iNOS, TNF-α and MCP-1 mRNA expressions in LPS-stimulated RAW264.7 cells. Further study showed that EPD didn't affect the phosphorylation and degradation of IκBα, but yet impeded the nuclear translocation of p65 to inhibit NF-κB activation. Meanwhile, it also prevented JNK, ERK1/2 and p38 phosphorylation to dampen the activation of AP-1. In endotoxemia mouse model, EPD not only decreased interleukin-6, TNF-α and MCP-1 levels in serum, but also potently ameliorated diarrhea. These findings provide the theoretical basis for PD to treat inflammatory diseases, especially intestinal inflammation.

Deletion of Cdk5 in Macrophages Ameliorates Anti-Inflammatory Response during Endotoxemia through Induction of C-Maf and Il-10.

Immune response control is critical as excessive cytokine production can be detrimental and damage the host. Interleukin-10 (Il-10), an anti-inflammatory cytokine produced primarily by macrophages, is a key regulator that counteracts and controls excessive inflammatory response. Il-10 expression is regulated through the transcription factor c-Maf. Another regulator of Il-10 production is p35, an activator of the cyclin-dependent kinase 5 (Cdk5), which decreases Il-10 production in macrophages, thus increasing inflammation. However, Cdk5 regulation of c-Maf and the involvement of Il-10 production in macrophages has not yet been investigated. We used in vitro primary bone marrow-derived macrophages (BMDMs) lacking Cdk5, stimulated them with lipopolysaccharid (LPS) and observed increased levels of c-Maf and Il-10. In an in vivo mouse model of LPS-induced endotoxemia, mice lacking Cdk5 in macrophages showed increased levels of c-Maf and elevated levels of Il-10 in lungs as well as in plasma, resulting in ameliorated survival. Taken together, we identified Cdk5 as a potential novel regulator of Il-10 production through c-Maf in macrophages under inflammatory conditions. Our results suggest that inhibition of Cdk5 enhances the c-Maf-Il-10 axis and thus potentiates improvement of anti-inflammatory therapy.