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Systemic inflammatory response syndrome (SIRS) is an uncontrolled systemic inflammatory response. Proanthocyanidins (PC) is a general term of polyphenol compounds widely existed in blueberry fruits and can treat inflammation-related diseases. This study aimed to explore the regulatory effect of PC on lipopolysaccharide (LPS)-induced systemic inflammation and its potential mechanism, providing effective strategies for the further development of PC. Here, RAW264.7 macrophages were stimulated with LPS to establish an inflammation model in vitro, while endotoxin shock mouse models were constructed by LPS in vivo. The function of PC was investigated by MTT, ELISA kits, H&E staining, immunohistochemistry, and Western blot analysis. Functionally, PC could demonstrate the potential to mitigate mortality in mice with endotoxin shock, as well as attenuated the levels of inflammatory cytokines (IL-6, TNF-α) and biochemical indicators (AST, ALT, CRE and BUN). Moreover, it had a significant protective effect on lung and kidney tissues damage. Mechanistically, PC exerted anti-inflammatory effects by inhibiting the activation of the NF-κB/NLRP3 signaling pathway. PC might have the potential ability of anti-inflammatory effects via modulation of the NF-κB/NLRP3 signaling pathway. [ABSTRACT FROM AUTHOR]

Sepsis is characterized by a dysfunctional host response to infection culminating in life-threatening organ failure that requires complex patient management and rapid intervention. Timely diagnosis of the underlying cause of sepsis is crucial, and identifying those at risk of complications and death is imperative for triaging treatment and resource allocation. Here, we explored the potential of explainable machine learning models to predict mortality and causative pathogen in sepsis patients. By using a modelling pipeline employing multiple feature selection algorithms, we demonstrate the feasibility of identifying integrative patterns from clinical parameters, plasma biomarkers, and extensive phenotyping of blood immune cells. While no single variable had sufficient predictive power, models that combined five and more features showed a macro area under the curve (AUC) of 0.85 to predict 90-day mortality after sepsis diagnosis, and a macro AUC of 0.86 to discriminate between Gram-positive and Gram-negative bacterial infections. Parameters associated with the cellular immune response contributed the most to models predictive of 90-day mortality, most notably, the proportion of T cells among PBMCs, together with expression of CXCR3 by CD4+ T cells and CD25 by mucosal-associated invariant T (MAIT) cells. Frequencies of Vδ2+ γδ T cells had the most profound impact on the prediction of Gram-negative infections, alongside other T-cell-related variables and total neutrophil count. Overall, our findings highlight the added value of measuring the proportion and activation patterns of conventional and unconventional T cells in the blood of sepsis patients in combination with other immunological, biochemical, and clinical parameters. This study explores the potential of explainable machine learning models to predict mortality and causative pathogen in sepsis patients and demonstrates the feasibility to identify integrative patterns from clinical parameters, plasma biomarkers, and phenotyping of blood cells. While no single variable had sufficient predictive power, models that combined five and more features were able to predict 90-day mortality after sepsis diagnosis, and discriminate between Gram-positive and Gram-negative bacterial infections. Overall, our findings highlight the added value of measuring the proportion and activation patterns of conventional and unconventional T cells in the blood of sepsis patients in combination with other immunological, biochemical, and clinical parameters. Graphical Abstract [ABSTRACT FROM AUTHOR]

Neutrophils play a pivotal role in innate immunity by releasing neutrophils extracellular traps (NETs). Excessive NETs are detrimental to the local tissue and further exacerbate inflammation. Protein arginine deiminases (PAD) mediate histone citrullination and NET formation that, in turn, exacerbate endotoxin shock damages. In this study, we further investigated the molecular mechanism underlying PAD and NETs in endotoxic stress in mice. The control group mice were injected with solvent, the LPS endotoxic shock group mice were intraperitoneally injected with LPS at 35 mg/kg only, while the LPS and PAD inhibitor YW3-56 treatment group mice were injected with YW3-56 at 10 mg/kg prior to the LPS injection. YW3-56 significantly prolonged the survival time of the LPS-treated mice. NETs, cfDNA, and inflammatory factors were detected by ELISA in serum, paitoneal cavity, and lung at 24 h after LPS administration. Lung injuries were detected by immunostaining, and lung tissue transcriptomes were analyzed by RNA-seq at 24 h after LPS administration. We found that YW3-56 altered neutrophil tissue homeostasis, inhibited NET formation, and significantly decreased cytokines (IL-6, TNFα and IL-1β) levels, cytokines gene expression, and lung tissue injury. In summary, NET formation inhibition offers a new avenue to manage inflammatory damages under endotoxic stress. [ABSTRACT FROM AUTHOR]

Objective: This review aims to present the current understanding of endotoxin tolerance (ET) in chronic inflammatory diseases and explores the potential connection with periodontitis. Summary: Subsequent exposure to lipopolysaccharides (LPS) triggers ET, a phenomenon regulated by different mechanisms and pathways, including toll‐like receptors (TLRs), nuclear factor kappa‐light‐chain enhancer of activated B‐cells (NFκB), apoptosis of immune cells, epigenetics, and microRNAs (miRNAs). These mechanisms interconnect ET with chronic inflammatory diseases including periodontitis. While the direct correlation between ET and periodontal destruction has not been fully elucidated, emerging reports point towards the potential tolerization of human periodontal ligament cells (hPDLCs) and gingival tissues with a significant reduction of TLR levels. Conclusions: There is a potential link between ET and periodontal diseases. Future studies should explore the crucial role of ET in the pathogenesis of periodontal diseases, as evidence of a tolerized oral mucosa may represent an intrinsic mechanism capable of regulating the oral immune response. A clear understanding of this host immune regulatory mechanism might lead to effective and more predictable therapeutic strategies to treat chronic inflammatory diseases and periodontitis. [ABSTRACT FROM AUTHOR]

Bergamottin is a natural furanocoumarin compound that possesses antioxidative and anti-cancer properties; however, the effect of Bergamottin on lipopolysaccharide (LPS)-induced inflammation response is unknown. In this study, we investigated the protective effects and mechanisms of Bergamottin against LPS-induced inflammatory responses. Raw264.7 cells were pre-treated with Bergamottin, then stimulated with LPS. Morphologic analysis and flow cytometry were used to measure Bergamottin-related cytotoxicity. ELISA and qPCR were performed to measure secretion and transcription activities of inflammatory cytokines. Biochemical analysis was used to determine the expression of tissues damage indicators. Western blots were used to determine protein expression, and immunofluorescence staining was used to determine the co-localization of NF-κB and RelA. Hematoxylin and eosin staining was used to show the pathological damages. Bergamottin had no cytotoxic effects on Raw264.7 cells. Pre-treatment with Bergamottin inhibited inflammatory cytokines expression and secretion induced by LPS, due to the inhibition of LPS-induced NF-κB signaling pathway activation, and improved pathological damages. These findings suggest that Bergamottin protects against LPS-induced endotoxin shock by regulating the NF-κB signaling pathway. [ABSTRACT FROM AUTHOR]

Objectives: Septic (or endotoxin) shock is a severe systemic inflammatory disease caused by bacteraemia or endotoxaemia. Although it is known that increased serum levels of CD163 are observed in septic/endotoxin shock patients, the exact function and significance of CD163 in macrophage activation remain unclear. Therefore, in the current study, we tested whether CD163 contributes to the pathogenesis of endotoxin shock in mice. Methods and results: In samples obtained from autopsy, the number of CD163‐positive macrophages was increased in the kidney, liver, heart, bone marrow and spleen of patients who had died from septic/endotoxin shock when compared to patients who had died from other causes. The animal study revealed a significantly lower survival rate in CD163‐deficient mice after lipopolysaccharide (LPS) injection. Several cytokines and oxidative stress‐related molecules were significantly elevated in the sera of LPS‐induced endotoxin shock mice models. Higher concentrations of IL‐6, TNF‐α, IL‐1β, nitrite (NO2‐) and nitrate (NO3‐) and a lower concentration of IL‐10 were observed in CD163‐deficient mice treated with LPS. Similar results were observed in CD163‐deficient LPS‐stimulated macrophages. Furthermore, in an antitype II collagen antibody‐induced arthritis (CAIA), rheumatoid arthritis model, inflammation and bone erosion scores as well as the expression of IL‐6 and IL‐1β were significantly increased in CD163‐deficient mice. Conclusions: CD163 was suggested to be involved in the regulation of inflammatory cytokine expression in septic/endotoxin shock and CAIA. [ABSTRACT FROM AUTHOR]

Objective: To investigate the effects of CCK-8 on mean pulmonary artery pressure in rats with endotoxic shock. Methods: Male SD rats were randomized into seven groups (n=6): control group, model group, LPS+CCK-8 group, CCK-8 group, CCK-1R antagonist group, CCK- 2R antagonist group, DFSO+PF group. The rats were induced to lethal endotoxic shock by an injection of LPS (30 mg.kg-1). CCK-8 (50 µg. kg-1) was administered 30 min after LPS injection. Either a specific CCK-1R antagonist or CCK-2R antagonist was injected before CCK-8 treatment. The mean arterial pressure (MAP) and mean pulmonary artery pressure (MPAP) were collected by a multi-channel data physiological recorder. As well as the 8h mortality was recorded. Results: Compared with control group, the MAP were significantly continuously lower and the MPAP significantly higher in model group. Administration of CCK-8 significantly delayed the LPS-induced not only decreases in MAP but also rises in MPAP, while reduceing the mortality. In addition, the specific antagonist at the CCK-2 receptor (CCK-2R) abrogated the action of CCK-8 significantly. Conclusion: while the LPSinduced hypotension delayed, CCK-8 could effectively alleviate the LPS-induced rises in MPAP via the CCK-2 receptor in ES rat model, while reduceing the mortality. [ABSTRACT FROM AUTHOR]

Macrophages play a critical role in the pathogenesis of endotoxin shock by producing excessive amounts of pro-inflammatory cytokines. A pan-caspase inhibitor, zVAD, can be used to induce necroptosis under certain stimuli. The role of zVAD in both regulating the survival and activation of macrophages, and the pathogenesis of endotoxin shock remains not entirely clear. Here, we found that treatment of mice with zVAD could significantly reduce mortality and alleviate disease after lipopolysaccharide (LPS) challenge. Notably, in LPS-challenged mice, treatment with zVAD could also reduce the percentage of peritoneal macrophages by promoting necroptosis and inhibiting pro-inflammatory responses in macrophages. In vitro studies showed that pretreatment with zVAD promoted LPS-induced nitric oxide-mediated necroptosis of bone marrow-derived macrophages (BMDMs), leading to reduced pro-inflammatory cytokine secretion. Interestingly, zVAD treatment promoted the accumulation of myeloid-derived suppressor cells (MDSCs) in a mouse model of endotoxin shock, and this process inhibited LPS-induced pro-inflammatory responses in macrophages. Based on these findings, we conclude that treatment with zVAD alleviates LPS-induced endotoxic shock by inducing macrophage necroptosis and promoting MDSC-mediated inhibition of macrophage activation. Thus, this study provides insights into the effects of zVAD treatment in inflammatory diseases, especially endotoxic shock.

Bronchopulmonary dysplasia (BPD) is the most common morbidity complicating premature birth. Importantly, preclinical models have demonstrated that IL-1 receptor antagonism prevents the lung injury and subsequent abnormal development that typically results following perinatal exposure to inflammatory stresses. This receptor is activated by two pro-inflammatory cytokines, IL-1α and IL-1β. While many studies have linked IL-1β to BPD development, IL-1α is relatively under-studied. The objective of our study was to determine whether systemic inflammatory stress induces IL-1α expression in the neonatal lung, and if so, whether this expression is mediated by innate immune NFκB signaling. We found that endotoxemia induced IL-1α expression during the saccular stage of neonatal lung development and was not present in the other neonatal organs or the adult lung. This IL-1α expression was dependent upon sustained pulmonary NFκB activation, which was specific to the neonatal lung. Using in vivo and in vitro approaches, we found that pharmacologic and genetic inhibition of NFκB signaling attenuated IL-1α expression. These findings demonstrate that innate immune regulation of IL-1α expression is developmentally regulated and occurs via an NFκB dependent mechanism. Importantly, the specific role of developmentally regulated pulmonary IL-1α expression remains unknown. Future studies must determine the effect of attenuating innate immune IL-1α expression in the developing lung before adopting broad IL-1 receptor antagonism as an approach to prevent neonatal lung injury.

The pathophysiology of renal failure in septic shock is complex. Although microvascular dysfunction has been proposed as a mechanism, there are controversial findings about the characteristics of microvascular redistribution and the effects of resuscitation. Our hypothesis was that the normalization of systemic hemodynamics with fluids and norepinephrine fails to improve acute kidney injury. To test this hypothesis, we assessed systemic and renal hemodynamics and oxygen metabolism in 24 anesthetized and mechanically ventilated sheep. Renal cortical microcirculation was evaluated by SDF-videomicroscopy. Shock (n = 12) was induced by intravenous administration of endotoxin. After 60 min of shock, 30 mL/kg of saline solution was infused and norepinephrine was titrated to reach a mean blood pressure of 70 mmHg for 2 h. These animals were compared with a sham group (n = 12). After endotoxin administration, mean blood pressure, cardiac index, and systemic O2 transport and consumption decreased (P < 0.05 for all). Resuscitation improved these variables. Endotoxin shock also reduced renal blood flow and O2 transport and consumption (205[157-293] vs. 131 [99-185], 28.4 [19.0-38.2] vs. 15.8[13.5-23.2], and 5.4[4.0-8.8] vs. 3.7[3.3-4.5] mL·min-1·100 g-1, respectively); cortical perfused capillary density (23.8[23.5-25.9] vs. 17.5[15.1-19.0] mm/mm2); and creatinine clearance (62.4[39.2-99.4] vs. 10.7[4.4-23.5] mL/min). After 2 h of resuscitation, these variables did not improve (174[91-186], 20.5 [10.8-22.7], and 3.8[1.9-4.8] mL·min-1·100 g-1, 19.9[18.6-22.1] mm/mm2, and 5.9[1.0-11.9] mL/min). In conclusion, endotoxin shock induced severe renal failure associated with decreased renal flow, O2 transport and consumption, and cortical microcirculation. Normalization of systemic hemodynamics with fluids and norepinephrine failed to improve renal perfusion, oxygenation, and function. NEW & NOTEWORTHY This experimental model of endotoxin shock induced severe renal failure, which was associated with abnormalities in renal regional blood flow, microcirculation, and oxygenation. Derangements included the compromise of peritubular microvascular perfusion. Improvements in systemic hemodynamics through fluids and norepinephrine were unable to correct these abnormalities. [ABSTRACT FROM AUTHOR]

Macrophages play a critical role in the pathogenesis of endotoxin shock by producing excessive amounts of pro-inflammatory cytokines. A pan-caspase inhibitor, zVAD, can be used to induce necroptosis under certain stimuli. The role of zVAD in both regulating the survival and activation of macrophages, and the pathogenesis of endotoxin shock remains not entirely clear. Here, we found that treatment of mice with zVAD could significantly reduce mortality and alleviate disease after lipopolysaccharide (LPS) challenge. Notably, in LPS-challenged mice, treatment with zVAD could also reduce the percentage of peritoneal macrophages by promoting necroptosis and inhibiting pro-inflammatory responses in macrophages. In vitro studies showed that pretreatment with zVAD promoted LPS-induced nitric oxide-mediated necroptosis of bone marrow-derived macrophages (BMDMs), leading to reduced pro-inflammatory cytokine secretion. Interestingly, zVAD treatment promoted the accumulation of myeloid-derived suppressor cells (MDSCs) in a mouse model of endotoxin shock, and this process inhibited LPS-induced pro-inflammatory responses in macrophages. Based on these findings, we conclude that treatment with zVAD alleviates LPS-induced endotoxic shock by inducing macrophage necroptosis and promoting MDSC-mediated inhibition of macrophage activation. Thus, this study provides insights into the effects of zVAD treatment in inflammatory diseases, especially endotoxic shock. [ABSTRACT FROM AUTHOR]

Bronchopulmonary dysplasia (BPD) is the most common morbidity complicating premature birth. Importantly, preclinical models have demonstrated that IL-1 receptor antagonism prevents the lung injury and subsequent abnormal development that typically results following perinatal exposure to inflammatory stresses. This receptor is activated by two pro-inflammatory cytokines, IL-1α and IL-1β. While many studies have linked IL-1β to BPD development, IL-1α is relatively under-studied. The objective of our study was to determine whether systemic inflammatory stress induces IL-1α expression in the neonatal lung, and if so, whether this expression is mediated by innate immune NFκB signaling. We found that endotoxemia induced IL-1α expression during the saccular stage of neonatal lung development and was not present in the other neonatal organs or the adult lung. This IL-1α expression was dependent upon sustained pulmonary NFκB activation, which was specific to the neonatal lung. Using in vivo and in vitro approaches, we found that pharmacologic and genetic inhibition of NFκB signaling attenuated IL-1α expression. These findings demonstrate that innate immune regulation of IL-1α expression is developmentally regulated and occurs via an NFκB dependent mechanism. Importantly, the specific role of developmentally regulated pulmonary IL-1α expression remains unknown. Future studies must determine the effect of attenuating innate immune IL-1α expression in the developing lung before adopting broad IL-1 receptor antagonism as an approach to prevent neonatal lung injury. [ABSTRACT FROM AUTHOR]

Endotoxin shock in rats led to intravenous bolus of bacterial lipopolysaccharide (LPS) was accompanied by oxidative stress and increase of NO level in livers, lungs, kidneys, hearts of animals. The intravenous administration of bienzyme superoxide dismutase - chondroitin sulphate - catalase conjugate (SOD-CHS-CAT) showed its anti-endotoxemia action in rats at preventive (before initiation of injury) and therapeutic (after start of injury) application during cytokine phase of injury and influence on further stages of the damage. The injection of antioxidant SOD-CHS-CAT conjugate in a therapeutic regime did not demonstrate significant alterations of No level in livers, lungs, kidneys, hearts of rats (as compared to indices of the rat group with LpS action only) and displayed protective action on the kidney function by altered urea and creatinine in blood. The therapeutic effect of SOD-CHS-CAT was demonstrated by increase in organism viability. The effects of intravenous injection of SOD-CHS-CAT in a rat model of endotoxin shock showed a variety in the activity of this conjugate in addition to prevention of NO conversion in peroxynitrite upon interaction with O2 superoxide radical. The results of accelerated normalization of arterial blood pressure and heart rate, a significant decrease in rat lethality because of using SOD-CHS-CAT conjugate indicate the importance of the determination of action mechanism of the cardiovascular injury models associated with other vasoactive agents besides NO. The further research of vascular damage pathogenesis and evaluation of its role in oxidative stress (time and place) are of paramount importance.

Dysregulation of macrophage has been demonstrated to contribute to aberrant immune responses and inflammatory diseases. CD11b, expressed on macrophages, plays a critical role in regulating pathogen recognition, phagocytosis, and cell survival. In the present study, we explored the effect of leukadherin-1 (LA1), an agonist of CD11b, on regulating LPS-induced pro-inflammatory response in macrophages and endotoxic shock. Intriguingly, we found that LA1 could significantly reduce mortalities of mice and alleviated pathological injury of liver and lung in endotoxic shock. In vivo studies showed that LA1-induced activation of CD11b significantly inhibited the LPS-induced pro-inflammatory response in macrophages of mice. Moreover, LA1-induced activation of CD11b significantly inhibited LPS/IFN-γ-induced pro-inflammatory response in macrophages by inhibiting MAPKs and NF-κB signaling pathways in vitro. Furthermore, the mice injected with LA1-treated BMDMs showed fewer pathological lesions than those injected with vehicle-treated BMDMs in endotoxic shock. In addition, we found that activation of TLR4 by LPS could endocytose CD11b and activation of CD11b by LA1 could endocytose TLR4 in vitro and in vivo, subsequently blocking the binding of LPS with TLR4. Based on these findings, we concluded that LA1-induced activation of CD11b negatively regulates LPS-induced pro-inflammatory response in macrophages and subsequently protects mice from endotoxin shock by partially blocking LPS-TLR4 interaction. Our study provides a new insight into the role of CD11b in the pathogenesis of inflammatory diseases.

Dysregulation of macrophage has been demonstrated to contribute to aberrant immune responses and inflammatory diseases. CD11b, expressed on macrophages, plays a critical role in regulating pathogen recognition, phagocytosis, and cell survival. In the present study, we explored the effect of leukadherin-1 (LA1), an agonist of CD11b, on regulating LPS-induced pro-inflammatory response in macrophages and endotoxic shock. Intriguingly, we found that LA1 could significantly reduce mortalities of mice and alleviated pathological injury of liver and lung in endotoxic shock. In vivo studies showed that LA1-induced activation of CD11b significantly inhibited the LPS-induced pro-inflammatory response in macrophages of mice. Moreover, LA1-induced activation of CD11b significantly inhibited LPS/IFN-γ-induced pro-inflammatory response in macrophages by inhibiting MAPKs and NF-κB signaling pathways in vitro. Furthermore, the mice injected with LA1-treated BMDMs showed fewer pathological lesions than those injected with vehicle-treated BMDMs in endotoxic shock. In addition, we found that activation of TLR4 by LPS could endocytose CD11b and activation of CD11b by LA1 could endocytose TLR4 in vitro and in vivo , subsequently blocking the binding of LPS with TLR4. Based on these findings, we concluded that LA1-induced activation of CD11b negatively regulates LPS-induced pro-inflammatory response in macrophages and subsequently protects mice from endotoxin shock by partially blocking LPS-TLR4 interaction. Our study provides a new insight into the role of CD11b in the pathogenesis of inflammatory diseases. [ABSTRACT FROM AUTHOR]

High-mobility group box 1 (HMGB1) is a highly conserved DNA-binding nuclear protein that facilitates gene transcription and the DNA repair response. However, HMGB1 may be released by necrotic cells as well as activated monocytes and macrophages following stimulation with lipopolysaccharide (LPS), interleukin-1β (IL-1β), or tumor necrosis factor-α (TNF-α). Extracellular HMGB1 plays a critical role in the pathogenesis of acute lung injury (ALI) through activating the nuclear transcription factor κB (NF-κB) P65 pathway, thus, it may be a promising therapeutic target in shock-induced ALI. Paeonol (Pae) is the main active component of Paeonia suffruticosa , which has been used to inhibit the inflammatory response in traditional Chinese medicine. We have proven that Pae inhibits the expression, relocation and secretion of HMGB1 in vitro. However, the role of Pae in the HMGB1-NF-κB pathway remains unknown. We herein investigated the role of Pae in LPS-induced ALI rats. In this study, LPS induced a marked decrease in the mean arterial pressure (MAP) and survival rate (only 25% after 72 h), and induced severe pathological changes in the lung tissue of rats, which was accompanied by elevated expression of HMGB1 and its downstream protein NF-κB P65. Treatment with Pae significantly improved the survival rate (>60%) and MAP, and attenuated the pathological damage to the lung tissue in ALI rats. Western blotting revealed that Pae also inhibited the total expression of HMGB1, NF-κB P65 and TNF-α in the lung tissue of ALI rats. Moreover, Pae increased the expression of HMGB1 in the nucleus, inhibited the production of HMGB1 in the cytoplasm, and decreased the expression of P65 both in the nucleus and cytoplasm of lung tissue cells in LPS-induced ALI rats. The results were in agreement with those observed in the in vitro experiment. These findings indicate that Pae may be a potential treatment for ALI through its repression of the HMGB1-NF-κB P65 signaling pathway. [ABSTRACT FROM AUTHOR]

Inflammasomes are multiprotein complexes that control the maturation and production of interleukin-1 family members and play crucial roles in host defense against pathogens. However, dysregulated activation of inflammasomes is associated with intense inflammation, leading to the development of inflammatory diseases. Therefore, inflammasomes must be activated at a proper strength to protect against infection and avoid tissue damage. Recent studies have highlighted the cross-talk between inflammasome activation and autophagy, the cellular machinery associated with the degradation of intracellular components and maintenance of cellular homeostasis. Notably, deficiencies in autophagy-related proteins induce the aberrant activation of inflammasomes, causing severe tissue damage. In contrast, autophagy inducers ameliorate symptoms of inflammasome-related diseases. In this review, we discuss recent advances in the involvement of autophagy in regulating inflammasomes activation and in the development of inflammatory diseases. [ABSTRACT FROM AUTHOR]

Pectin, a water-soluble dietary fiber, has been found to improve survival in endotoxin shock. However, the underlying mechanism by which pectin exerts its protective effect against endotoxin shock remains unknown. Apart from its prebiotic effects, it has been suggested that pectin directly affects immune cells to regulate inflammatory responses. In this study, we investigated the direct effect of pectin in murine model of endotoxin shock. Citrus pectin solution was administered to male C57BL/6 mice for 10 days. Thereafter, hypothermia was induced in the mice with intraperitoneal injection of lipopolysaccharide (LPS). The pectin-treated mice showed attenuation of both the decrease in rectal temperature and increase in serum IL-6 level as compared to vehicle control mice. Simultaneously, the pectin-treated mice showed reduced levels of inflammatory cytokine mRNA in Peyer's patches and mesenteric lymph nodes, but not in the spleen. Peyer's patch cells from the pectin-treated mice were sorted and their levels of IL-6 production on LPS stimulation were measured. The results of ex vivo analysis indicated that IL-6 secretion from CD11c+ cells was suppressed by oral administration of pectin. Furthermore, IL-6 secretion from Toll-like receptor (TLR)-activated RAW264.7 cells was suppressed by pretreatment with pectin in vitro. This suppression was observed even with degraded pectin pretreatment but not with polygalacturonic acid, as the principal constituent of the pectin backbone. Taken together, these results suggest that pectin intake suppresses TLR-induced inflammatory cytokine expression in Peyer's patch myeloid cells, presumably through inhibition of TLR signaling by the pectin side chains. [ABSTRACT FROM AUTHOR]

The pathogenesis of sepsis involves a dual inflammatory response, with a hyperinflammatory phase followed by, or in combination with, a hypoinflammatory phase. The adhesion molecules lymphocyte function-associated antigen (LFA-1) (CD11a/CD18) and macrophage-1 (Mac-1) (CD11b/CD18) support leucocyte adhesion to intercellular adhesion molecules and phagocytosis through complement opsonization, both processes relevant to the immune response during sepsis. Here, we investigate the role of soluble (s)CD18 in sepsis with emphasis on sCD18 as a mechanistic biomarker of immune reactions and outcome of sepsis. sCD18 levels were measured in 15 septic and 15 critically ill non-septic patients. Fifteen healthy volunteers served as controls. CD18 shedding from human mononuclear cells was increased in vitro by several proinflammatory mediators relevant in sepsis. sCD18 inhibited cell adhesion to the complement fragment iC3b, which is a ligand for CD11b/CD18, also known as Mac-1 or complement receptor 3. Serum sCD18 levels in sepsis non-survivors displayed two distinct peaks permitting a partitioning into two groups, namely sCD18 'high' and sCD18 'low', with median levels of sCD18 at 2158 mU/ml [interquartile range (IQR) 2093-2811 mU/ml] and 488 mU/ml (IQR 360-617 mU/ml), respectively, at the day of intensive care unit admission. Serum sCD18 levels partitioned sepsis non-survivors into one group of 'high' sCD18 and low CRP and another group with 'low' sCD18 and high C-reactive protein. Together with the mechanistic data generated in vitro, we suggest the partitioning in sCD18 to reflect a compensatory anti-inflammatory response syndrome and hyperinflammation, respectively, manifested as part of sepsis. [ABSTRACT FROM AUTHOR]

Previous studies have shown that targeted deletion of endothelial lipase (EL) markedly increases the plasma high density lipoprotein cholesterol (HDL-C) level in mice. However, little is known about the functional quality of HDL particles after EL inhibition. Therefore, the present study assessed the functional quality of HDL isolated from EL−/− and wild-type (WT) mice. Anti-inflammatory functions of HDL from EL−/− and WT mice were evaluated by in vitro assays. The HDL functions such as PON-1 or PAF-AH activities, inhibition of cytokine-induced vascular cell adhesion molecule-1 expression, inhibition of LDL oxidation, and the ability of cholesterol efflux were similar in HDL isolated from WT and EL−/− mice. In contrast, the lipopolysaccharide-neutralizing capacity of HDL was significantly higher in EL−/− mice than that in WT mice. To evaluate the anti-inflammatory actions of HDL in vivo, lipopolysaccharide-induced systemic inflammation was generated in these mice. EL−/− mice showed higher survival rate and lower expression of inflammatory markers than WT mice. Intravenous administration of HDL isolated from EL−/− mice significantly improved the mortality after lipopolysaccharide injection in WT mice. In conclusion, targeted disruption of EL increased HDL particles with preserved anti-inflammatory and anti-atherosclerotic functions. Thus, EL inhibition would be a useful strategy to raise 'good’ cholesterol in the plasma.

Surfactant protein D (SP-D) is an innate host defense protein that clears infectious pathogens from the lung and regulates pulmonary host defense cells. SP-D is also detected in lower concentrations in plasma and many other non-pulmonary tissues. Plasma levels of SP-D increase during infection and other proinflammatory states; however, the source and functions of SP-D in the systemic circulation are largely unknown. We hypothesized that systemic SP-D may clear infectious pathogens and regulate host defense cells in extrapulmonary systems. To determine if SP-D inhibited inflammation induced by systemic lipopolysaccharide (LPS), E.coli LPS was administered to mice via tail vein injection with and without SP-D and the inflammatory response was measured. Systemic SP-D has a circulating half-life of 6 h. Systemic IL-6 levels in mice lacking the SP-D gene were similar to wild type mice at baseline but were significantly higher than wild type mice following LPS treatment (38,000 vs 29,900 ng/ml for 20 mg/kg LPS and 100,700 vs 73,700 ng/ml for 40 mg/kg LPS). In addition, treating wild type mice with purified intravenous SP-D inhibited LPS induced secretion of IL-6 and TNFα in a concentration dependent manner. Inhibition of LPS induced inflammation by SP-D correlated with SP-D LPS binding suggesting SP-D mediated inhibition of systemic LPS requires direct SP-D LPS interactions. Taken together, the above results suggest that circulating SP-D decreases systemic inflammation and raise the possibility that a physiological purpose of increasing systemic SP-D levels during infection is to scavenge systemic infectious pathogens and limit inflammation-induced tissue injury. [ABSTRACT FROM AUTHOR]

Viral infections can give rise to secondary bacterial infections. In the present study, we examined the role of invariant natural killer T (iNKT) cells in lipopolysaccharide (LPS)-induced lethal shock during encephalomyocarditis virus (EMCV) infection. Wild-type (WT) mice and Jα18 gene knockout (Jα18 KO) mice were inoculated with EMCV, 5 days prior to challenging with LPS. The survival rate of Jα18 KO mice subjected to EMCV and LPS was significantly higher than that of WT mice. TNF-α and nitric oxide (NO) production were increased in WT mice, than that in Jα18 KO mice, after the administration of EMCV and LPS. EMCV infection increased the number of iNKT cells and IFN-γ production by iNKT cells in WT mice. Moreover, EMCV infection enhanced the expression of Toll-like receptor 4 (TLR4) in the lung and spleen. IFN-γ also increased the expression of TLR4 in splenocytes. These findings indicated that EMCV infection activated iNKT cells, and IFN-γ secreted from the iNKT cells up-regulated the expression of TLR4 in various tissues. As a result, EMCV-infected mice were susceptible to LPS and easily developed the lethal shock. In conclusion, iNKT cells were involved in the development of LPS-induced lethal shock during EMCV infection. [ABSTRACT FROM AUTHOR]

Porphyran, a sulfated polysaccharide, isolated from discolored nori ( Porphyra yezoensis ) (dc-porphyran) and one fraction (F1) purified from dc-porphyran by DEAE-chromatography showed the protective effects on LPS-induced endotoxin shock in mice. Intraperitoneal (i.p.) treatment with dc-porphyran or F1 (100 mg/kg) 60 min prior to i.p. injection of LPS (30 mg/kg) completely protected mice from LPS lethality. At 10 mg/kg concentration, F1 demonstrated more protection than dc-porphyran. Intravenous (i.v.) challenge of LPS, even at 20 mg/kg, was more lethal than i.p. administration; i.v. injection of F1 (100 mg/kg) with LPS significantly improved the survival rate. However, i.v. dc-porphyran (100 mg/kg) produced an even lower survival rate than that of LPS alone. We examined pro-inflammatory mediators such as NO and TNF-α in serum. F1 significantly reduced the levels of these markers. Additionally, F1 significantly decreased the malondialdehyde level in the liver, a marker of oxidative stress, while dc-porphyran had almost no effect. Furthermore, F1 significantly decreased the production of TNF-α and NO in peritoneal exudate cells harvested from LPS-challenged mice, while dc-porphyran treatment showed a lesser decrease. Our results suggest that porphyran isolated from discolored nori, especially F1, is capable of suppressing LPS-induced endotoxin shock in vivo . [ABSTRACT FROM AUTHOR]

Esculin, a coumarin compound derived from the traditional Chinese herbs such as Cortex Fraxini , has long been used for treating inflammatory and vascular diseases. In present study, we analyzed the role of esculin against macrophages and endotoxin shock induced by lipopolysaccharide (LPS) in mice. Here, we demonstrated that esculin suppressed inflammatory reactions in macrophages and protected mice from LPS-induced endotoxin shock. We found that esculin significantly inhibited the production of nitric oxide (NO) production via the inhibition of nuclear factor-κB (NF-κB) activation in macrophages. In animal model, esculin pretreatment significantly improved the survival rate of mice. LPS-induced increase of tumor necrosis factor alpha (TNF-α) and interleukin-6 (IL-6) in serum, lung, liver and kidney were markedly inhibited by esculin. IL-10, an anti-inflammatory cytokine, was up-regulated by esculin. Moreover, the histopathological analyses showed that esculin significantly attenuated the tissues injury of lung, liver, kidney in endotoxic mice. In addition, esculin significantly diminished the protein expression of NF-κB p65 in lung, liver, kidney, which resulted in lower levels of inflammatory mediators. These results suggest that esculin may be a potential drug for treatment of various inflammatory diseases. [ABSTRACT FROM AUTHOR]

This study tested the hypothesis that the initial fall in arterial pressure evoked by lipopolysaccharide ( LPS) is mediated by the ventrolateral column of the midbrain periaqueductal gray region (vl PAG). To test this hypothesis, the local anaesthetic lidocaine (2%; 0.1 μL, 0.2 μL or 1.0 μL), the delta opioid receptor antagonist naltrindole (2 nmol) or saline was microinjected into the vl PAG of isoflurane-anaesthetized rats bilaterally and LPS (1 mg/kg) or saline was administered intravenously 2 min later. Both lidocaine and naltrindole inhibited LPS-evoked hypotension significantly but did not affect arterial pressure in saline-treated control animals. Neither lidocaine nor naltrindole altered heart rate significantly in either LPS-treated or control animals. Microinjection of lidocaine or naltrindole into the dorsolateral PAG was ineffective. These data indicate that the vl PAG plays an important role in the initiation of endotoxic hypotension and further show that delta opioid receptors in the vl PAG participate in the response. [ABSTRACT FROM AUTHOR]

Alarmins are identified as endogenous mediators that have potent immune-activating abilities. High mobility group nucleosome binding domain 1 (HMGN1), a highly conserved, non-histone chromosomal protein, which binds to the inner side of the nucleosomal DNA, regulates chromatin dynamics and transcription in cells. Furthermore, HMGN1 acts as a cytokine in the extracellular milieu by inducing the recruitment and maturation of antigen-presenting cells (dendritic cells) to enhance Th1-type antigen-specific immune responses. Thus, HMGN1 is expected to act as an alarmin, when released into the extracellular milieu. The present study investigated the release mechanism of HMGN1 from macrophages using mouse macrophage-like RAW264.7 cells. The results indicated that HMGN1 was released from lipopolysaccharide (LPS)-stimulated RAW264.7 cells, accompanied by cell death as assessed by the release of lactate dehydrogenase (LDH). Subsequently, the patterns of cell death involved in HMGN1 release from LPS-stimulated RAW264.7 cells were determined using a caspase-1 inhibitor, YVAD, and a necroptosis inhibitor, Nec-1. YVAD and Nec-1 did not alter LPS-induced HMGN1 and LDH release, suggesting that pyroptosis (caspase-1-activated cell death) and necroptosis are not involved in the release of HMGN1 from LPS-stimulated RAW264.7 cells. In addition, flow cytometric analysis indicated that LPS stimulation did not induce apoptosis but substantially augmented necrosis, as evidenced by staining with annexin V/propidium iodide. Together these findings suggest that HMGN1 is extracellularly released from LPS-stimulated RAW264.7 macrophage-like cells, accompanied by unprogrammed necrotic cell death but not pyroptosis, necroptosis or apoptosis. [ABSTRACT FROM AUTHOR]