Penehyclidine hydrochloride inhibits the release of high-mobility group box 1 in lipopolysaccharide-activated RAW264.7 cells and cecal ligation and puncture-induced septic mice

Penehyclidine hydrochloride protects against lipopolysaccharide-induced acute lung injury by promoting the PI3K/Akt pathway

INTRODUCTION

Acute lung injury (ALI) attracted attention among physicians because of its high mortality. We aimed to determine whether the phosphatidylinositol-3 kinase (PI3K)/protein kinase B (Akt) pathway is involved in the protective effects of penehyclidine hydrochloride (PHC) against lipopolysaccharide (LPS)-induced ALI.

METHODS

H&E staining was used to observed pathological changes in the lung tissues. ELISA was used to evaluate the concentration of inflammatory mediators in the bronchoalveolar lavage fluid (BALF). White-light microscopy was performed to observe the TUNEL-positive nuclei. The viability of NR8383 alveolar macrophages was determined by using CCK-8. The levels of MPO, MDA, SOD, and GSH-Px were analyzed using ELISA kits. Western blotting was used to evaluate the ERS-associated protein levels and the phosphorylation of PI3K and Akt.

RESULTS

PHC administration defended against LPS-induced histopathological deterioration and increased pulmonary edema and lung injury scores, while all of these beneficial effects were inhibited by LY. In addition, PHC administration mitigated oxidative stress as indicated by decreases in lung myeloperoxidase (MPO) and malondialdehyde (MDA) concentrations, and increases in glutathione peroxidase (GSH-Px) and superoxide dismutase (SOD) concentrations. It also alleviated LPS-induced inflammation. PHC administration attenuated apoptosis-associated protein levels, improved cell viability, and decreased the number of TdT-mediated dUTP Nick-End Labeling (TUNEL)-positive cells. Furthermore, PHC inhibited ERS-associated protein levels. Meanwhile, the protection of PHC against inflammation, oxidative stress, apoptosis, and ERS was inhibited by LY. Moreover, PHC administration increased PI3K and Akt phosphorylation, indicating that the upregulation of the PI3K/Akt pathway, while this pathway was inhibited by LY.

CONCLUSION

PHC significantly activates the PI3K/Akt pathway to ameliorate the extent of damage to pulmonary tissue, inflammation, oxidative stress, apoptosis, and ERS in LPS-induced ALI.

Ozone exposure promotes pyroptosis in rat lungs via the TLR2/4-NF-κB-NLRP3 signaling pathway

OBJECTIVE

Ozone has become a major air pollutant in recent years, which leading to a variety of lung diseases. This study aimed to explore the mechanisms of pyroptosis and related signaling pathways in ozone-induced lung injury.

METHODS

We exposed 120 Wistar rats to ozone, 20 in each group (half male and half female). Ozone exposure concentrations were 0, 0.12, 0.5, 1.0, 2.0 and 4.0 ppm for 6 h. At the same time, we isolated and cultured type I alveolar epithelial cells, then intervened with high mobility group box 1 protein (HMGB1), hyaluronic acid (HA) and Toll-like receptors 2/4 (TLR2/4) inhibitor. In animal experiments, histopathological experiments, TUNEL, ELISA and biochemical indicators were performed. RT-qPCR and western blot experiments assay were used to detect the expression changes of key factors in relevant signal pathways in vivo and in vitro.

RESULTS

After acute ozone exposure, the levels of lung cell injury indicators in bronchoalveolar lavage fluid (BALF), as well as the levels of inflammatory factors in BALF, blood, and lung tissue were significantly increased. Male rats were more sensitive to ozone exposure. Low-concentration ozone exposure caused mild interstitial inflammation in rat lung tissue. Severe inflammation and pulmonary edema appeared with increases in concentration. ELISA results in BALF showed that HMGB1 and HA expressions increased gradually with the increase of ozone exposure concentration. RT-qPCR and Western blot showed that when ozone concentrations increased above 0.5 ppm, the expression of nucleotide-binding domain, leucine-rich-containing family, pyrin domain-containing 3 (NLRP3), cleaved caspase-1, and N-gasdermin D (N-GSDMD) in the lung tissue increased significantly, suggesting that ozone exposure induces pyroptosis. At the same time, it was found that ozone exposure activated the nuclear factor kappa B (NF-κB) signal pathway, and increased the mRNA expressions of Toll-like receptors TLR2/4. The results of cell experiments showed that after the addition of HMGB1 and HA, the expression of NF-κB and pyroptosis related indexes increased in type I alveolar epithelial cells, while the corresponding expression decreased after the addition of TLR2/4 inhibitors.

CONCLUSION

Ozone exposure causes lung injury in a dose- and gender-dependent manner, and is more severe in males. When injured, the levels of HMGB1 and HA in BALF increased, which interact with TLR 2/4 to activate the downstream NF-κB signaling pathway. Further activating the NLRP3 inflammasome complex and regulating the ozone-induced pyroptosis.

The AKT inhibitor MK2206 suppresses airway inflammation and the pro‑remodeling pathway in a TDI‑induced asthma mouse model

The cellular and molecular mechanisms via which MK2206, an AKT inhibitor, prevents the activation of AKT in toluene diisocyanate (TDI)‑induced asthma remain unclear. Thus, the present study aimed to evaluate the potential effects of MK2206 on airway AKT activation, inflammation and remodeling in a TDI‑induced mouse model of asthma. A total of 24 BALB/c mice were selected and randomly divided into untreated (AOO), asthma (TDI), MK2206 (TDI + MK2206), and dexamethasone (TDI + DEX) groups. Phosphorylated AKT (p‑AKT), total AKT, airway remodeling indices, α‑smooth muscle actin (α‑SMA) and collagen I levels in pulmonary tissue were measured using western blotting. Airway inflammation factors, including interleukin (IL)‑4, ‑5, ‑6, and ‑13 in bronchoalveolar lavage fluid (BALF) and IgE in serum, were determined using ELISA. Additionally, the airway hyperresponsiveness (AHR) and pulmonary pathology of all groups were evaluated. The results of the present study demonstrated that p‑AKT levels in lung protein lysate were upregulated, and neutrophil, eosinophil and lymphocyte counts were increased in the lungs obtained from the asthma group compared with the AOO group. Both MK2206 and DEX treatment in TDI‑induced mice resulted not only in the attenuation of AKT phosphorylation, but also reductions in neutrophil, eosinophil and lymphocyte counts in the lungs of mice in the asthma group. Consistently, increases in the levels of the inflammatory cytokines IL‑4, ‑5, ‑6 and ‑13 analyzed in BALF, and serum IgE in the TDI group were demonstrated to be attenuated in the TDI + MK2206 and TDI + DEX groups. Furthermore, α‑SMA and AHR were significantly attenuated in the TDI + MK2206 group compared with the TDI group. These results revealed that MK2206 not only inhibited AKT activation, but also served a role in downregulating airway inflammation and airway remodeling in chemical‑induced asthma. Therefore, the findings of the present study may provide important insight into further combination therapy.

Synergistic effect of halofuginone and dexamethasone on LPS‑induced acute lung injury in type II alveolar epithelial cells and a rat model

Acute lung injury (ALI) is characterized by neutrophilic infiltration, uncontrolled oxidative stress and inflammatory processes. Despite various therapeutic regimes having been performed, there remains no effective pharmacotherapy available to treat ALI. Halofuginone (HF), a ketone isolated from Dichroa febrifuga, exhibits significant anti‑inflammatory and antifibrotic effects. Dexamethasone (DEX), a synthetic glucocorticoid, has been routinely used as an adjuvant therapy in treating inflammatory diseases, including ALI. The present study aimed to investigate the effects of the combination of HF and DEX in the treatment of ALI. The present results suggested that the simultaneous administration of HF and DEX markedly decreased the level of pro‑inflammatory cytokines and increased the level of anti‑inflammatory cytokines, as assessed by western blot analysis. In addition, HF and DEX effectively decreased nuclear factor‑κB activity via suppressing the phosphorylation of P65 in lipopolysaccharide (LPS)‑induced human pulmonary alveolar epithelial cells (HPAEpiC) and lung tissues extracted from ALI rats, as determined by immunofluorescence. Furthermore, in vivo experiments demonstrated that the combination of HF and DEX in LPS‑induced ALI rats defended against lung fibrosis, perivascular inflammation, congestion and edema of pulmonary alveoli, as assessed by histopathological analysis, TUNEL staining and immunohistochemistry assay. Taken together, the present study indicated the synergistic effect of HF and DEX on LPS‑induced ALI in HPAEpiC cells and a rat model. These results offer a novel therapeutic approach for the treatment of ALI.

Ulinastatin Protects Against LPS-Induced Acute Lung Injury By Attenuating TLR4/NF-κB Pathway Activation and Reducing Inflammatory Mediators

Acute lung injury (ALI) and its severe form, acute respiratory distress syndrome, remain the leading causes of morbidity and mortality in intensive care units. Ulinastatin (UTI), a serine protease inhibitor, possesses anti-inflammatory properties and has been suggested to modulate lipopolysaccharide (LPS)-induced sepsis; thus, it is now widely used in the treatment of pancreatitis, sepsis, and septic shock. Toll-like receptor 4 (TLR4), an essential LPS signaling receptor, plays a critical role in the activation of innate immunity. The aim of this study was to investigate whether UTI alleviates ALI by attenuating TLR4 expression and to explore the underlying molecular mechanisms involved. Male C56BL/6 mice were administered UTI intravenously 1 h before and 6 h after exposure to LPS by intratracheal instillation. Human lung epithelial (BEAS-2B) cells were incubated with LPS in the presence or absence of UTI. An enzyme-linked immunosorbent assay was used to detect levels of inflammatory cytokines. Western blot analysis was performed to detect changes in TLR4 expression and nuclear factor-κB (NF-κB) activation. UTI significantly protected animals from LPS-induced ALI, decreasing the lung wet/dry weight ratio, ALI score, total cells, neutrophils, macrophages, myeloperoxidase activity, and malondialdehyde content, factors associated with lung histological damage. UTI treatment also markedly attenuated levels of TLR4 and other proinflammatory cytokines. Furthermore, UTI significantly attenuated LPS-induced increases in TLR4 protein expression and NF-κB activation in lung tissues. Similarly, UTI markedly attenuated TLR4 expression and NF-κB activation in LPS-stimulated BEAS-2B cells. These findings indicate that UTI ameliorates LPS-induced ALI by attenuating the TLR4/NF-κB pathway activation.

Penehyclidine hydrochloride defends against LPS-induced ALI in rats by mitigating endoplasmic reticulum stress and promoting the Hes1/Notch1 pathway

Penehyclidine hydrochloride (PHC) is a novel anticholinergic drug applied broadly in surgeries as a preanesthetic medication. A substantial amount of research indicates that PHC has lung defensive properties. Considering that endoplasmic reticulum (ER) stress exerts a crucial function in cell apoptosis associated with the lipopolysaccharides (LPS)-induced acute lung injury (ALI) model, we aimed to determine whether regulation of ER stress in the LPS-induced ALI model was associated with the lung defensive role of PHC. Adult male SD rats were administered LPS (5 mg/kg, intratracheally) followed by PHC (1.0 mg/kg, intravenously) for 24 h. The NR8383 alveolar macrophages were randomly separated into Sham, LPS (100 ng/mL), and PHC (1, 2.5, or 5 μg/mL) + LPS groups. PHC (1, 2.5, or 5 μg/mL) + LPS groups were treated with PHC alone for 1 h after LPS exposure. Posttreatment with PHC relieved LPS-induced pulmonary impairment and blocked LPS-mediated lung apoptosis, indicated by the downregulation of the lung apoptotic indicators malondialdehyde and superoxide dismutase in serum at 24 h after LPS-induced ALI. PHC (1-5 μg/mL) did not influence the activity of cultivated NR8383 alveolar macrophages in vitro. However, postconditioning with PHC dosage-dependently reduced LPS-mediated cell apoptosis. Additionally, many studies have indicated that PHC administration inhibits ER stress and initiates hairy and enhancer of split 1 (Hes1)/(Notch1) signaling by decreasing phosphorylated α subunit of eukaryotic initiation factor 2α (p-eIF2α)/eukaryotic translation initiation factor 2α (eIF2α) and Phospho-protein kinase R-like ER kinase (p-PERK)/ protein kinase R-like ER kinase (PERK) proportions; inhibiting C/EBP-homologous protein (CHOP), activating transcription factor 4 (ATF4), caspase-3, and Bcl2-associated x (Bax) activity; and enhancing notch1 intracellular domain (NICD), Notch1, B-cell lymphoma-2 (Bcl-2), and Hes1 activity in vivo and in vitro. In addition, the defensive functions of PHC on LPS-activated NR8383 alveolar macrophages were abrogated through the Notch1 pathway antagonist [(3,5-difluorophenacetyl)-1-alanyl] -phenylglycine-butyl ester (DAPT). In conclusion, PHC alleviates LPS-induced ALI by ameliorating ER stress-mediated apoptosis and promoting Hes1/Notch1 signaling in vivo and in vitro.

Resveratrol protects against asthma-induced airway inflammation and remodeling by inhibiting the HMGB1/TLR4/NF-κB pathway

The aim of the present study was to explore the protective role of resveratrol (RES) in asthma-induced airway inflammation and remodeling, as well as its underlying mechanism. An asthma rat model was induced by ovalbumin (OVA) treatment. Rats were randomly assigned into sham, asthma, 10 µmol/l RES and 50 µmol/l RES groups. The amount of inflammatory cells in rat bronchoalveolar lavage fluid (BALF) was detected. Pathological lesions in lung tissues were accessed by hematoxylin and eosin (H&E), and Masson's trichrome staining. Levels of inflammatory factors in lung homogenate were detected via ELISA. The blood serum of asthmatic and healthy children was also collected for analysis. Reverse transcription-quantitative polymerase chain reaction was performed to detect high mobility group box 1 (HMGB1), Τoll-like receptor 4 (TLR4), myeloid differentiation primary response gene 88 (MyD88) and NF-κB expression in asthmatic and healthy children, as well as rats of the different groups. H&E staining demonstrated that multiple inflammatory cell infiltration into the rat airway epithelium of the asthma group occurred whilst the 50 µmol/l RES group displayed alleviated pathological lesions. Masson staining indicated that there was an increased airway collagen deposition area in the asthma and 10 µmol/l RES groups compared with the 50 µmol/l RES group. The number of inflammatory cells in BALF extracted from rats of the asthma and 10 µmol/l RES groups was higher compared with the 50 µmol/l RES group. Treatment with 50 µmol/l RES significantly decreased the thicknesses of the airway wall and smooth muscle. ELISA results illustrated that interleukin (IL)-1, IL-10 and tumor necrosis factor-α (TNF-α) levels were elevated, whereas IL-12 level was reduced in lung tissues of the asthma and 10 µmol/l RES groups whilst the 50 µmol/l RES group demonstrated the opposite trend. HMGB1, TLR4, MyD88 and NF-κB mRNA levels were remarkably elevated in rats of the asthma and 10 µmol/l RES groups compared with the 50 µmol/l RES group. Serum levels of IL-1, IL-10 and TNF-α were elevated, whereas IL-12 was reduced in asthmatic children compared with healthy children. The present results demonstrated that a large dose of RES alleviated asthma-induced airway inflammation and airway remodeling by inhibiting the release of inflammatory cytokines via the HMGB1/TLR4/NF-κB pathway.

High-Mobility Group Box 1 (HMGB1) and Autophagy in Acute Lung Injury (ALI): A Review

Acute lung injury (ALI) is a life-threatening clinical syndrome in critically ill patients. The identification of novel biological markers for the early diagnosis of ALI and the development of more effective treatments are topics of current research. High mobility group box-1 protein (HMGB1) is a late inflammatory mediator associated with sepsis, malignancy, and immune disease. Levels of HMGB1 may reflect the severity of inflammation and tissue damage, indicating a potential role for HMGB1 as a prognostic biomarker in ALI, and a potential target for blocking inflammatory pathways. Several studies have shown that HMGB1 regulates autophagy. Autophagy, or type II programmed cell death, is an essential biological process that maintains cellular homeostasis. Studies have shown that HMGB1 and autophagy are involved in the pathogenesis of many lung diseases including ALI but the specific mechanisms underlying this association remain to be determined. This review aims to provide an update on the current status of the role of HMBG1 and autophagy in ALI.

Penehyclidine Hydrochloride Decreases Pulmonary Microvascular Endothelial Inflammatory Injury Through a Beta-Arrestin-1-Dependent Mechanism

Penehyclidine hydrochloride (PHC), a type of hyoscyamus drug, has both antimuscarinic and antinicotinic activities and retains potent central and peripheral anticholinergic activities. Compared with other hyoscyamine, the notable advantage of PHC is that it has few M₂ receptor-associated cardiovascular side effects. Recent studies and clinical trials have suggested that treatment with penehyclidine hydrochloride may also possess good effects in the treatment of lung injury. The mechanism responsible for this effect has yet to be determined; however, one possibility is that they might do so by a direct effect on pulmonary vascular endothelium. Since inflammatory reactions of the endothelium are signs of endothelial injury in the pathogenesis of lung injury, we determined the effects of penehyclidine hydrochloride on endothelial inflammatory injury in cultured human pulmonary microvascular endothelial cells (HPMVEC). Furthermore, human pulmonary microvascular endothelial cells were transfected with a shRNA-containing plasmid that specifically targets beta-arrestin-1 mRNA, to test whether the effect of penehyclidine hydrochloride on lipopolysaccharide (LPS)-induced endothelial cell injury is dependent on its upregulation of beta-arrestin-1 or not. Penehyclidine hydrochloride reduced the inflammatory responses to LPS stimulation, as evidenced by reduced lactate dehydrogenase (LDH), tumor necrosis factor-alpha (TNF-α), and interleukelin-6 (IL-6) levels, as well as vascular cell adhesion molecule 1 (VCAM-1) and intercellular cell adhesion molecule-1 (ICAM-1) expressions. This was found to result from increased beta-arrestin-1 expression and decreased nuclear transcription factor-κB (NF-κB) activation. Expression of a shRNA-containing plasmid that specifically targets beta-arrestin-1 mRNA nullified these effects of penehyclidine hydrochloride. The results indicate that penehyclidine hydrochloride exerts a protective effect on pulmonary microvascular endothelial inflammatory injury induced by LPS. We also demonstrate that this is due to its ability to increase beta-arrestin-1, which in turn inhibits NF-κB activation.

MicroRNA-381 reduces inflammation and infiltration of macrophages in polymyositis via downregulating HMGB1

The downregulation of microRNA (miR)-381 has been detected in various diseases. The present study aimed to investigate the effects, and underlying mechanisms of miR-381 on inflammation and macrophage infiltration in polymyositis (PM). A mouse model of experimental autoimmune myositis (EAM) was generated in this study. Hematoxylin and eosin staining was conducted to detect the inflammation of muscle tissues. In addition, ELISA and immunohistochemistry were performed to determine the expression levels of associated factors, and reverse transcription-quantitative polymerase chain reaction and western blotting were used to detect the expression levels of related mRNAs and proteins. A luciferase activity assay was used to confirm the binding of miR-381 and high mobility group box 1 (HMGB1) 3' untranslated region. Transwell assays were also performed to assess the migratory ability of macrophages. The results demonstrated that serum creatine kinase (s-CK), HMGB1 and cluster of differentiation (CD)163 expression in patients with PM were increased compared within healthy controls. Conversely, the expression levels of miR-381 were downregulated in patients with PM. Furthermore, high HMGB1 expression was associated with poor survival rate in patients with PM. In the mouse studies, muscle inflammation and CD163 expression were decreased in the anti-IL-17 and anti-HMGB1 groups, compared with in the EAM model group. The expression levels of s-CK, HMGB1, IL-17 and intercellular adhesion molecule (ICAM)-1 were also downregulated in response to anti-IL-17 and anti-HMGB1. These findings indicated that HMGB1 was closely associated with inflammatory responses. In addition, the present study indicated that transfection of macrophages with miR-381 mimics reduced the migration of inflammatory macrophages, and the expression levels of HMGB1, IL-17 and ICAM-1. Conversely, miR-381 inhibition exerted the opposite effects. The effects of miR-381 inhibitors were reversed by HMGB1 small interfering RNA. In conclusion, miR-381 may reduce inflammation and the infiltration of macrophages; these effects were closely associated with the downregulation of HMGB1.

Protective effects of scopolamine and penehyclidine hydrochloride on acute cerebral ischemia-reperfusion injury after cardiopulmonary resuscitation and effects on cytokines

The objective of this study was to investigate the protective effects of scopolamine and penehyclidine hydrochloride on acute cerebral ischemia-reperfusion injury after cardiopulmonary resuscitation, and the effect on cytokine levels. Eighty patients with cardiac arrest admitted to our hospital from June 2011 to December 2015 were recruited and randomly divided into two groups (n=40 each). Following cardiopulmonary resuscitation, scopolamine was administered in the control group, whereas penehyclidine hydrochloride was administered in the observation group. After intervention, the following medical indicators were compared between the groups: Intracranial pressure, cerebral oxygen partial pressure, cerebral perfusion pressure, assessment of the balance of cerebral oxygen supply and demand, levels of neuron-specific enolase (NSE) and blood lactic acid, levels of oxidative stress markers, and levels of inflammatory-related factors. Additionally, the areas of brain tissue edema and National Institutes of Health Stroke Scale (NIHSS) scores before and after intervention were compared. Rescue success rates of the groups were recorded. After intervention, the following indicators were lower in the observation group than in the control group: Intracranial pressure (p<0.05), levels of NSE (p<0.05), levels of blood lactic acid (p<0.05), levels of malondialdehyde (p<0.05), and levels of interleukin 6 (IL-6), tumor necrosis factor-α, IL-1, and hs-CRP (p<0.05). However, the following indicators were higher in the observation group than in the control group: Cerebral oxygen partial pressure, cerebral perfusion pressure (p<0.05), levels of CaO₂, CjvO₂, and CERO₂ (p>0.05), and levels of superoxide dismutase and glutathione peroxidase (p<0.05). Additionally, the areas of brain tissue edema after intervention were smaller in the observation group than those before intervention and those after intervention in the control group (p<0.05). Similarly, the NIHSS scores after intervention in the observation group were lower than those before intervention and those after intervention in the control group (p<0.05). Rescue success rate was significantly higher in observation group than in control group (p<0.05). In conclusion, administration of penehyclidine following cardiopulmonary resuscitation can effectively improve cerebral perfusion pressure, lower intracranial pressure, reduce brain tissue edema and inflammation, and improve neurological function.

M3 receptor is involved in the effect of penehyclidine hydrochloride reduced endothelial injury in LPS-stimulated human pulmonary microvascular endothelial cell

LPS has been recently shown to induce muscarinic acetylcholine 3 receptor (M₃ receptor) expression and penehyclidine hydrochloride (PHC) is an anticholinergic drug which could block the expression of M₃ receptor. PHC has been demonstrated to perform protective effect on cell injury. This study is to investigate whether the effect of PHC on microvascular endothelial injury is related to its inhibition of M₃ receptor or not. HPMVECs were treated with specific M₃ receptor shRNA or PBS, and randomly divided into LPS group (A group), LPS+PHC group (B group), LPS + M₃ shRNA group (C group) and LPS + PHC + M₃ shRNA group (D group). Cells were collected at 60 min after LPS treatment to measure levels of LDH, endothelial permeability, TNF-α and IL-6 levels, NF-κB p65 activation, I-κB protein expression, p38MAPK, and ERK1/2 activations as well as M₃ mRNA expression. PHC could decrease LDH levels, cell permeability, TNF-α and IL-6 levels, p38 MAPK, ERK1/2, NF-κB p65 activations and M₃ mRNA expressions compared with LPS group. When M₃ receptor was silence, the changes of these indices were much more obvious. These findings suggest that M₃ receptor plays an important role in LPS-induced pulmonary microvascular endothelial injury, which is regulated through NF-κB p65 and MAPK activation. And knockout of M₃ receptor could attenuate LPS-induced pulmonary microvascular endothelial injury. Regulative effects of PHC on pulmonary microvascular permeability and NF-κB p65 as well as MAPK activations are including but not limited to inhibition of M₃ receptor.

[Association between high-mobility group box 1 and neonatal respiratory distress syndrome]

OBJECTIVE

To study the association between serum level of high-mobility group box 1(HMGB1) and neonatal respiratory distress syndrome (NRDS).

METHODS

A total of 35 infants with NRDS and 35 normal neonates (control group) were enrolled. Peripheral venous blood samples were collected with 12-24 hours after birth. ELISA was used to measure the serum level of HMGB1.

RESULTS

The infants with mild and severe NRDS had a significantly higher serum level of HMGB1 than the control group (P<0.05). The infants with severe NRDS had a significantly higher serum level of HMGB1 than those with mild NRDS (P<0.05). The infants with NRDS who died had a significantly higher serum level of HMGB1 than those who survived (P<0.05). The receiver operating characteristic (ROC) curve showed that the optimal cut-off value for serum level of HMGB1 to predict NRDS was 625.3 pg/mL with an area under the ROC curve (AUC) of 0.846 (95%CI: 0.755-0.936), and the optimal cut-off value for serum level of HMGB1 to predict the death of infants with NRDS was 772.2 pg/mL with an AUC of 0.916 (95%CI: 0.813-1.000).

CONCLUSIONS

Infants with NRDS have a significant increase in the serum level of HMGB1, and the serum level of HMGB1 can well predict the development and prognosis of NRDS.

Propofol Protects Rats and Human Alveolar Epithelial Cells Against Lipopolysaccharide-Induced Acute Lung Injury via Inhibiting HMGB1 Expression

High-mobility group box 1 (HMGB1) plays a key role in the development of acute lung injury (ALI). Propofol, a general anesthetic with anti-inflammatory properties, has been suggested to be able to modulate lipopolysaccharide (LPS)-induced ALI. In this study, we investigated the effects of propofol on the expression of HMGB1 in a rat model of LPS-induced ALI. Rats underwent intraperitoneal injection of LPS to mimic sepsis-induced ALI. Propofol bolus (1, 5, or 10 mg/kg) was infused continuously 30 min after LPS administration, followed by infusion at 5 mg/(kg · h) through the left femoral vein cannula. LPS increased wet to dry weight ratio and myeloperoxidase activity in lung tissues and caused the elevation of total protein and cells, neutrophils, macrophages, and neutrophils in bronchoalveolar lavage fluid (BALF). Moreover, HMGB1 and other cytokine levels were increased in BALF and lung tissues and pathological changes of lung tissues were excessively aggravated in rats after LPS administration. Propofol inhibited all the above effects. It also inhibited LPS-induced toll-like receptor (TLR)2/4 protein upexpression and NF-κB activation in lung tissues and human alveolar epithelial cells. Propofol protects rats and human alveolar epithelial cells against HMGB1 expression in a rat model of LPS-induced ALI. These effects may partially result from reductions in TLR2/4 and NF-κB activation.

Ulinastatin post-treatment attenuates lipopolysaccharide-induced acute lung injury in rats and human alveolar epithelial cells

Ulinastatin (UTI), a serine protease inhibitor, possesses anti-inflammatory properties and has been suggested to modulate lipopolysaccharide (LPS)-induced acute lung injury (ALI). High-mobility group box 1 (HMGB1), a nuclear DNA-binding protein, plays a key role in the development of ALI. The aim of this study was to investigate whether UTI attenuates ALI through the inhibition of HMGB1 expression and to elucidate the underlying molecular mechanisms. ALI was induced in male rats by the intratracheal instillation of LPS (5 mg/kg). UTI was administered intraperitoneally 30 min following exposure to LPS. A549 alveolar epithelial cells were incubated with LPS in the presence or absence of UTI. An enzyme-linked immunosorbent assay was used to detect the levels of inflammatory cytokines. Western blot analysis was performed to detect the changes in the expression levels of Toll-like receptor 2/4 (TLR2/4) and the activation of nuclear factor-κB (NF-κB). The results revealed that UTI significantly protected the animals from LPS-induced ALI, as evidenced by the decrease in the lung wet to dry weight ratio, total cells, neutrophils, macrophages and myeloperoxidase activity, associated with reduced lung histological damage. We also found that UTI post-treatment markedly inhibited the release of HMGB1 and other pro-inflammatory cytokines. Furthermore, UTI significantly inhibited the LPS-induced increase in TLR2/4 protein expression and NF-κB activation in lung tissues. In vitro, UTI markedly inhibited the expression of TLR2/4 and the activation of NF-κB in LPS-stimulated A549 alveolar epithelial cells. The findings of our study indicate that UTI attenuates LPS-induced ALI through the inhibition of HMGB1 expression in rats. These benefits are associated with the inhibition of the activation of the TLR2/4-NF-κB pathway by UTI.

13-Methylberberine reduces HMGB1 release in LPS-activated RAW264.7 cells and increases the survival of septic mice through AMPK/P38 MAPK activation

High mobility group box 1 (HMGB1), a late phase cytokine of sepsis, is viewed as a potential target for the treatment of sepsis. The authors considered that 13-methylberberine (13-MB) might reduce circulating HMGB1 levels and increase survival in a mouse model of sepsis by activating AMP-activated protein kinase (AMPK). Western blot analysis and vascular contraction testing were performed using RAW264.7 cells and rat thoracic aorta, respectively. The mechanisms responsible were investigated using various signal inhibitors and small interfering RNA techniques. 13-MB significantly reduced HMGB1 release by LPS-activated RAW264.7 cells, and this was prevented by silencing AMPK or p38, or by pretreating cells with p38 MAPKinase inhibitor, suggesting that the activations of p38 and AMPK were responsible for the observed reduction in HMGB1 release. As was expected, 13-MB increased the phosphorylations of p38 and AMPK. Interestingly, phosphorylations of p38 by 13-MB were inhibited by AMPKsiRNA, indicating that AMPK lies upstream of p38. Furthermore, 13-MB concentration-dependently inhibited IκB phosphorylation in LPS-activated RAW264.7 cells, and in aortic rings, co-treatment with 13-MB and LPS for 8h, in vitro, significantly restored the isometric contraction induced by phenylephrine. Importantly, 13-MB significantly increased the survival rate of LPS-induced endotoxemic mice. These results suggest 13-MB may be useful for treating diseases in which HMGB1 is viewed as a target.

Ketamine reduces LPS-induced HMGB1 via activation of the Nrf2/HO-1 pathway and NF-κB suppression

BACKGROUND

Ketamine, as an anesthetic agent, has an anti-inflammatory effect. In the present study, we investigated whether ketamine inhibits release of high mobility group box 1 (HMGB1), a late-phase cytokine of sepsis, in lipopolysaccharide (LPS)-stimulated macrophages through heme oxygenase-1 (HO-1) induction.

METHODS

Macrophages were preincubated with various concentrations of ketamine and then treated with LPS (1 μg/mL). The cell culture supernatants were collected to measure inflammatory mediators (HMGB1, nitric oxide, tumor necrosis factor-α, and interleukin 1β) by enzyme-linked immunosorbent assay. Moreover, HO-1 protein expression, the phosphorylation and degradation of IκB-α, and the nuclear translocation of nuclear factor E2-related factor 2 and nuclear factor κB (NF-κB) p65 were tested by Western blot analysis. In addition, to further identify the role of HO-1 in this process, tin protoporphyrin (SnPP), an HO-1 inhibitor, was used.

RESULTS

Ketamine treatment dose-dependently attenuated the increased levels of proinflammatory mediators (HMGB1, nitric oxide, tumor necrosis factor α, and interleukin 1β) and increased the HO-1 protein expression in LPS-activated macrophages. Furthermore, ketamine suppressed the phosphorylation and degradation of IκB-α as well as the LPS-stimulated nuclear translocation of NF-κB p65 in macrophages. In addition, the present study also demonstrated that ketamine induced HO-1 expression through the nuclear translocation of nuclear factor E2-related factor 2 in macrophages. The effects of ketamine on LPS-induced proinflammatory cytokines production were partially reversed by the HO inhibitor tin protoporphyrin (SnPP).

CONCLUSION

Ketamine inhibits the release of HMGB1 in LPS-stimulated macrophages, and this effect is at least partly mediated by the activation of the Nrf2/HO-1 pathway and NF-κB suppression.

Postperfusion lung syndrome: physiopathology and therapeutic options

Postperfusion lung syndrome is rare but can be lethal. The underlying mechanism remains uncertain but triggering inflammatory cascades have become an accepted etiology. A better understanding of the pathophysiology and the roles of inflammatory mediators in the development of the syndrome is imperative in the determination of therapeutic options and promotion of patients' prognosis and survival. Postperfusion lung syndrome is similar to adult respiratory distress syndrome in clinical features, diagnostic approaches and management strategies. However, the etiologies and predisposing risk factors may differ between each other. The prognosis of the postperfusion lung syndrome can be poorer in comparison to acute respiratory distress syndrome due to the secondary multiple organ failure and triple acid-base imbalance. Current management strategies are focusing on attenuating inflammatory responses and preventing from pulmonary ischemia-reperfusion injury. Choices of cardiopulmonary bypass circuit and apparatus, innovative cardiopulmonary bypass techniques, modified surgical maneuvers and several pharmaceutical agents can be potential preventive strategies for acute lung injury during cardiopulmonary bypass.

Asiaticoside attenuates lipopolysaccharide-induced acute lung injury via down-regulation of NF-κB signaling pathway

Asiaticoside (AS), a triterpene glycoside isolated from Centella asiatica, has been shown to possess potent anti-inflammatory activity. However, the detailed molecular mechanisms of AS on lipopolysaccharide (LPS)-induced acute lung injury (ALI) model in mice are scanty. The purpose of this study was to evaluate the effect of AS on LPS-induced mouse ALI via down-regulation of NF-κB signaling pathway. We investigated the efficacy of AS on cytokine levels induced by LPS in bronchoalveolar lavage fluid (BALF) and RAW 264.7 cells. The production of cytokine (TNF-α and IL-6) was measured by enzyme-linked immunosorbent assay (ELISA). The lung wet-to-dry weight ratios were measured in LPS-challenged mice, and lung histopathologic changes observed via paraffin section were assessed. To further study the mechanism of AS protective effects on ALI, the activation of NF-κB p65 subunit and the degradation of IκBα were tested by western blot assay. We found that AS treatment at 15, 30 or 45mg/kg dose-dependently attenuated LPS-induced pulmonary inflammation by reducing inflammatory infiltration, histopathological changes, descended cytokine production, and pulmonary edema initiated by LPS. Furthermore, our results suggested that AS suppressed inflammatory responses in LPS-induced ALI through inhibition of the phosphorylation of NF-κB p65 subunit and the degradation of its inhibitor IκBα, and might be a new preventive agent of ALI in the clinical setting.

Hydrogen gas inhibits high-mobility group box 1 release in septic mice by upregulation of heme oxygenase 1

BACKGROUND

Sepsis is a potentially fatal whole-body inflammation caused by severe infection. Hydrogen gas (H2) is effective for treating sepsis. In this study, we hypothesized that the protective function of H2 in mice with septic lung injury occurred through the activation of heme oxygenase 1 (HO-1) and its upstream regulator nuclear factor-erythroid 2 p45-related factor 2 (Nrf2).

MATERIALS AND METHODS

Male institute of cancer research mice were subjected to sepsis by cecal ligation and puncture (CLP) with the presence or absence of H2. Beginning at 1 and 6 h after CLP or sham operation, respectively, 2% H2 was inhaled for 1 h. We intraperitoneally injected the HO-1 inhibitor zinc protoporphyrin IX (40 mg/kg) 1 h before CLP. To assess the severity of septic lung injury, we observed the 7-d survival rate, wet/dry weight ratio of lung, lung histopathologic score, oxygenation index, and so forth. Serum and homogenates from the lung, liver, and kidney were acquired for measuring the levels of high-mobility group box 1 (HMGB1) at 6, 12, and 24 h after CLP or sham operation. Furthermore, the protein and messenger RNA expression of Nrf2, HO-1, and HMGB1 was measured at 6, 12, and 24 h.

RESULTS

Septic mice had a lower survival rate and more severe lung injury compared with the sham group. However, therapy with H2 increased the survival rate and alleviated the severity of lung injury, reduced the HMGB1 level, and increased the HO-1 and Nrf2 levels in septic mice. Moreover, the HO-1 inhibitor zinc protoporphyrin IX significantly eliminated the protective effect of H2 on septic lung injury.

CONCLUSIONS

H2 plays a significant role in regulating the release of the inflammatory cytokine HMGB1 in septic mice, which is partially mediated through the activation of HO-1 as a downstream molecule of Nrf2.

HMGB1 in health and disease

Complex genetic and physiological variations as well as environmental factors that drive emergence of chromosomal instability, development of unscheduled cell death, skewed differentiation, and altered metabolism are central to the pathogenesis of human diseases and disorders. Understanding the molecular bases for these processes is important for the development of new diagnostic biomarkers, and for identifying new therapeutic targets. In 1973, a group of non-histone nuclear proteins with high electrophoretic mobility was discovered and termed high-mobility group (HMG) proteins. The HMG proteins include three superfamilies termed HMGB, HMGN, and HMGA. High-mobility group box 1 (HMGB1), the most abundant and well-studied HMG protein, senses and coordinates the cellular stress response and plays a critical role not only inside of the cell as a DNA chaperone, chromosome guardian, autophagy sustainer, and protector from apoptotic cell death, but also outside the cell as the prototypic damage associated molecular pattern molecule (DAMP). This DAMP, in conjunction with other factors, thus has cytokine, chemokine, and growth factor activity, orchestrating the inflammatory and immune response. All of these characteristics make HMGB1 a critical molecular target in multiple human diseases including infectious diseases, ischemia, immune disorders, neurodegenerative diseases, metabolic disorders, and cancer. Indeed, a number of emergent strategies have been used to inhibit HMGB1 expression, release, and activity in vitro and in vivo. These include antibodies, peptide inhibitors, RNAi, anti-coagulants, endogenous hormones, various chemical compounds, HMGB1-receptor and signaling pathway inhibition, artificial DNAs, physical strategies including vagus nerve stimulation and other surgical approaches. Future work further investigating the details of HMGB1 localization, structure, post-translational modification, and identification of additional partners will undoubtedly uncover additional secrets regarding HMGB1's multiple functions.

Penehyclidine hydrochloride decreases pulmonary microvascular permeability by upregulating beta arrestins in a murine cecal ligation and puncture model

BACKGROUND

Penehyclidine hydrochloride (PHC) is a new anticholinergic drug, which has been shown to have a good curative effect for sepsis. Beta arrestins have been demonstrated to play important roles in sepsis. This study is to investigate the effects of PHC on pulmonary microvascular permeability and on expressions of beta arrestins in lung injury induced by the cecal ligation and puncture (CLP) procedure.

MATERIALS AND METHODS

Thirty healthy female mice were randomly divided into three groups (n = 10 each): sham operation group (control group), CLP group (CLP group), and PHC 0.45 mg/kg group (PHC group). In the PHC group, mice were given an intraperitoneal injection of PHC 0.45 mg/kg 1 h before surgery. Mice in the other two groups received an intraperitoneal injection of the same volume of normal saline. At 12 h after surgery, serum and bronchoalveolar lavage fluid were collected to examine lung permeability index. The lung tissue samples were collected to examine expressions of myosin light chain kinase (MLCK), vascular endothelial-cadherin (VE-cadherin), vascular cell adhesion molecule 1 (VCAM-1), myeloperoxidase (MPO), NF-κB, and beta arrestins.

RESULTS

Compared with the control group, pulmonary microvascular permeability, MPO activity, NF-κB, VCAM-1, and MLCK expressions were significantly increased, whereas VE-cadherin and beta-arrestin protein expressions were obviously decreased in CLP group. Furthermore, compared with the CLP group, PHC group markedly decreased pulmonary microvascular permeability, MPO activity, NF-κB, VCAM-1, and MLCK expressions, and increased expressions of VE-cadherin and beta arrestins.

CONCLUSIONS

This study suggests that in the CLP-induced lung injury model, PHC could reduce pulmonary microvascular permeability by upregulating expressions of beta arrestins.