IL-27 is Elevated in Acute Lung Injury and Mediates Inflammation

Cytokines play a critical role in the development of acute lung injury (ALI)/acute respiratory distress syndrome (ARDS). Here we investigated whether IL-27 was elevated in patients with ALI/ARDS and its potential clinical significance. Bronchoalveolar lavage (BAL) and serum samples were obtained from 58 ALI/ARDS patients, and 25 control healthy volunteers. IL-27 and other inflammatory mediators were measured in BAL and serum by ELISA. Besides, a mouse model of cecal ligation and puncture (CLP)-induced lung inflammation/injury was established, and serum, BAL fluid and tissues were collected for analyses in the presence or absence of IL-27 neutralizing antibodies. BAL IL-27 was found to be significantly higher in patients with ALI/ARDS than that in controls, particularly of pulmonary origin; serum IL-27 was also significantly higher. Increased IL-27 was associated with markers of inflammation, and correlated with disease severity of patients in ALI/ARDS. In a mouse model of CLP-induced lung inflammation/injury, elevated IL-27 levels were observed in the lung, serum, and BAL fluids. IL-27 neutralizing antibody treatment reduced pulmonary inflammation and lung injury and improved mouse survival in response to CLP. Therefore, IL-27 is a critical cytokine in ALI/ARDS and inhibition of IL-27 may open a promising approach for ALI/ARDS patients.     

Rosiglitazone Dampens Pulmonary Inflammation in a Porcine Model of Acute Lung Injury

The hallmarks of acute lung injury (ALI) are the compromised alveolar-capillary barrier and the extravasation of leukocytes into the alveolar space. Given the fact that the peroxisome proliferator-activated receptor-γ agonist rosiglitazone holds significant anti-inflammatory properties, we aimed to evaluate whether rosiglitazone could dampen these hallmarks of local pulmonary inflammation in a porcine model of lung injury. For this purpose, we used a model of lipopolysaccharide (LPS, 50 μg/kg)-induced ALI. One hundred twenty minutes following the infusion of LPS, we started the exposure to rosiglitazone through inhalation or infusion. We found that intravenous rosiglitazone significantly controlled local pulmonary inflammation as determined through the expression of cytokines within the alveolar compartment. Furthermore, we found a significant reduction of the protein concentration and neutrophil activity within the alveolar space. In summary, we therefore conclude that the treatment with rosiglitazone might dampen local pulmonary inflammation during the initial stages of ALI.     

Effects of Urinary Trypsin Inhibitor on Lipopolysaccharide-Induced Acute Lung Injury in Rabbits

This study was undertaken to clarify the effects of urinary trypsin inhibitor (UTI) on lipopolysaccharide (LPS)-induced acute lung injury. Rabbits were randomly assigned to one of seven groups: saline only, UTI, LPS, pre- or post-UTI-high (infusion of UTI of 25,000 U/kg followed by 25,000 U/kg over 2 h), pre- or post-UTI-low (infusion of UTI of 2,500 U/kg followed by 2,500 U/kg over 2 h). UTI was administered 30 min before (pre-groups) or 15 min after (post-groups) LPS administration. Rabbits were mechanically ventilated with 40% oxygen for 6 h. LPS decreased peripheral blood leukocyte counts and increased wet/dry weight ratio of lung, lung injury score, neutrophil infiltration in lung, and IL-8 production in systemic blood and bronchoalveolar lavage fluid (BALF). Rabbits treated by UTI were protected from LPS-induced lung injury, as determined by wet/dry weight ratio, neutrophil infiltration in lung, lung injury score, and IL-8 in BALF levels. UTI attenuated LPS-induced acute lung injury in rabbits mainly by inhibiting neutrophil and IL-8 responses, which may play a central role in sepsis-related lung injury.     

Modulation of LPS-Stimulated Pulmonary Inflammation by Borneol in Murine Acute Lung Injury Model

The object of our study is to investigate the protective effects of Borneol on lipopolysaccharide (LPS)-induced acute lung injury (ALI) in mice. To determine the effects of Borneol on the histopathological changes in mice with ALI, inflammatory cell count in bronchoalveolar lavage fluid (BALF) and lung wet/dry weight ratio were measured in LPS-challenged mice, and lung histopathologic changes observed via paraffin section were assessed. Next, cytokine production induced by LPS in BALF and RAW 264.7 cells was measured by enzyme-linked imunosorbent assay (ELISA). To further study the mechanism of Borneol-protective effects on ALI, nuclear factor-kappaB (NF-κB) and mitogen-activated protein kinases (MAPKs) pathways were investigated. In the present study, Borneol obviously alleviated pulmonary inflammation by reducing inflammatory infiltration, histopathological changes, descended cytokine production, and pulmonary edema initiated by LPS. Furthermore, Borneol significantly suppressed phosphorylation of NF-κB/P65, IκBa, p38, JNK, and ERK. Taken together, our results suggest that Borneol suppressed inflammatory responses in LPS-induced acute lung injury through inhibition of the NF-κB and MAPKs signaling pathways. Borneol may be a promising potential preventive agent for acute lung injury treatment.     

Plasmacytoid Dendritic Cells Control Lung Inflammation and Monocyte Recruitment in Indirect Acute Lung Injury in Mice

Indirect acute lung injury (ALI, not caused by a direct insult to the lung) represents the first organ dysfunction in trauma patients, with nonpulmonary sepsis being the most common cause of indirect ALI. Dendritic cells (DCs) are thought to participate in a number of inflammatory lung diseases; however, their role in indirect ALI is currently not established. Using a clinically relevant model of indirect ALI induced in mice by hemorrhagic shock followed 24 hours later by polymicrobial septic challenge, we report that mature DC numbers were markedly increased in the lung during indirect ALI. DC depletion induced a significant increase in indirect ALI severity, which was associated with enhanced lung and plasma proinflammatory cytokine concentration and recruitment of proinflammatory CD115⁺ monocytes in response to increased lung monocyte chemotactic protein-1 production. Among the different DC subpopulations, plasmacytoid DCs, which were induced and activated in the lung during indirect ALI, were responsible for this effect because their specific depletion reproduced the observations made in DC-depleted mice. As the recruitment of monocytes to the lung plays a central deleterious role in the pathophysiology of indirect ALI, our data therefore position plasmacytoid DCs as important regulators of acute lung inflammation.Acute lung injury (ALI) and its most severe form, the acute respiratory distress syndrome (ARDS), are the two parts of a clinical syndrome defined by acute hypoxemic respiratory failure, bilateral pulmonary infiltrate attributable to edema, and normal cardiac filling pressures.¹Of those seriously injured trauma victims who survive the first hours immediately after injury, upwards of 50% develop some forms of multiple organ failure. In this respect, ALI is reported to be one of the most common forms of organ dysfunction in these individuals.^1,2 Every year, ALI and ARDS are thus the cause of more than 74,000 deaths in the United States.²This syndrome can be categorized into direct (pulmonary) and indirect (nonpulmonary) ALI. Epidemiologically, direct ALI accounts for 57% of all cases and is caused mainly by pneumonia, aspiration, and lung trauma. Indirect ALI accounts for the residual 43% with nonpulmonary sepsis being the most frequent underlying disease.³ Among all causes, sepsis is associated with the highest risk of progression to ALI (approximately 40%) and sepsis-associated ARDS carries the highest mortality rates from ARDS.^1,2,4 Importantly, patients developing ALI after nonpulmonary sepsis (indirect ALI) present with a higher mortality rate than patients with pulmonary sepsis (direct ALI).⁵Despite almost 35 years of intense investigation, the fundamental mechanisms that initiate and propagate lung injury have not yet been defined completely.¹ In particular, mechanisms leading to direct versus indirect ALI may be different, with pulmonary infections causing lung injury directly via the pathogen and host response versus nonpulmonary infections causing lung injury indirectly via systemic inflammation.¹ Moreover, findings from a number of studies suggest that “priming” of different cell types occurs and appears to play significant roles in mediating the increased inflammation associated with this injury.^1,6 However, despite a good understanding of the process that initiates and promotes host inflammation, little is known about the host immune cells that are responsible for the inhibition of the inflammatory response.Dendritic cells (DCs), both myeloid (mDCs) and plasmacytoid (pDCs), exist in the lung in relatively small numbers.^7,8 In this location, they are ideally positioned to play a central role in the immune response during infection/inflammation.^7,8 Indeed, a role for DCs has been shown in a number of lung inflammatory diseases in human (asthma, chronic obstructive pulmonary disease, lung cancer, or transplant rejection).⁷ Moreover, during ongoing inflammation, DCs migrate to the lung where they not only maintain and enhance local immune response, but also regulate this response.^7,9 Therefore, we hypothesized that DCs have a role in the pathophysiology of indirect ALI. We investigated this using a clinically relevant model of indirect ALI induced in mice by a hemorrhagic shock followed 24 hours later by a polymicrobial septic challenge.     

Methoxyeugenol Protects Against Lung Inflammation and Suppresses Neutrophil Extracellular Trap Formation in an LPS-Induced Acute Lung Injury Model

Inflammation - Acute lung injury (ALI) is a life-threatening acute inflammatory disease with high rates of morbidity and mortality worldwide. 4-Allyl-2,6-dimethoxyphenol (methoxyeugenol), a...     

CTRP-3 Regulates NOD1-mediated Inflammation and NOD1 Expression in Adipocytes and Adipose Tissue

The anti-inflammatory adipokine CTRP-3 might affect innate immune reactions such as NOD1. The impact of CTRP-3 on NOD1-mediated inflammation in adipocytes and monocytic cells as well as on NOD1 expression was investigated. Murine 3T3-L1 pre-adipocytes and adipocytes as well as human THP-1 monocyte-like cells were co-stimulated with the synthetic NOD1 agonist Tri-DAP and recombinant CTRP-3. Gonadal adipose tissue and primary adipocytes were obtained from a murine model carrying a knockout (KO) of CTRP-3 in adipocytes but not in stroma-vascular cells. Wildtype mice with lipopolysaccharide (LPS)-induced elevated NOD1 expression were treated with CTRP-3. Secreted inflammatory cytokines in cell supernatants were measured by ELISA and mRNA levels were quantified by RT-PCR. Pro-inflammatory chemokine and cytokine secretion (MCP-1, RANTES, TNFα) was induced by NOD1 activation in adipocytes and monocyte-like cells, and MCP-1 and RANTES release was effectively inhibited by pre-incubation of cells with CTRP-3. CTRP-3 also antagonized LPS-triggered induction of NOD1 gene expression in murine adipose tissue, whereas adipocyte CTRP-3 deficiency upregulated NOD1 expression in adipose tissue. CTRP-3 is an effective antagonist of peptidoglycan-induced, NOD1-mediated inflammation and of LPS-induced NOD1 expression. Since basal NOD1 expression is increased by adipocyte CTRP-3 deficiency, there have to be also inflammation-independent mechanisms of NOD1 expression regulation by CTRP-3.

     

急性肺损伤相关基因

急性肺损伤／呼吸窘迫综合征是常见的危重病之一,病因多,影响因素复杂。通过剖析其内在的本质,期望找到针对性治疗的突破口,改善预后,提高生存率。其病程中多种基因参与,包括易感基因以及参与病变的相关基因,就此作一综述。     

Treatment of Low Molecular Weight Heparin Inhibits Systemic Inflammation and Prevents Endotoxin-Induced Acute Lung Injury in Rats

To determine whether low molecular weight heparin (LMWH) is able to reduce pulmonary inflammation and improve the survival in rats with endotoxin-induced acute lung injury (ALI). Rat ALI model was reproduced by injection of lipopolysaccharide (LPS) into tail vein. Rats were divided randomly into three groups: control group, ALI group, LMWH-treated group. Blood was collected and lung tissue was harvested at the designated time points for analysis. The lung specimens were harvested for morphological studies, streptavidin-peroxidase immunohistochemistry examination. Lung tissue edema was evaluated by tissue water content. The levels of lung tissue myeloperoxidase (MPO) were determined. Meanwhile, the nuclear factor-kappa B (NF-κB) activation, tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β) levels and high mobility group box 1 (HMGB1) and intercellular adhesion molecule-1 (ICAM-1) protein levels in the lung were studied. In survival studies, a separate group of rats were treated with LMWH or sterile saline after LPS administration. Then, the mortality was recorded. Treatment with LMWH after ALI was associated with a reduction in the severity of LPS-induced lung injury. Treatment with LMWH significantly decreased the expression of TNF-α, IL-1β, HMGB1 and ICAM-1 in the lung of ALI rats. Similarly, treatment with LMWH dramatically diminished LPS-induced neutrophil sequestration and markedly reduced the enhanced lung permeability. In the present study, LMWH administration inhibited the nuclear translocation of NF-κB in the lung. Survival was significantly higher among the LMWH-treated group compared with the ALI group. These data suggest that LMWH attenuates inflammation and prevents lethality in endotoxemic rats.     

Formononetin Inhibited the Inflammation of LPS-Induced Acute Lung Injury in Mice Associated with Induction of PPAR Gamma Expression

Formononetin has shown a variety of pharmacologic properties including anti-inflammatory effect. In the present study, we analyzed the role of formononetin in acute lung injury induced by lipopolysaccharide (LPS) in mice. The cell counting in the bronchoalveolar lavage fluid (BALF) was measured. The animal lung edema degree was evaluated by wet/dry weight ratio. The superoxidase dismutase (SOD) activity and myeloperoxidase (MPO) activity was assayed by SOD and MPO kits, respectively. The levels of inflammatory mediators, tumor necrosis factor-α (TNF-α) and IL-6,were assayed by enzyme-linked immunosorbent assay method. Pathological changes of hung tissues were observed by HE staining. Peroxisome proliferator-activated receptor (PPAR)-γ gene expression was measured by real-time PCR. The data showed that treatment with the formononetin group markedly attenuated inflammatory cell numbers in the BALF, increased PPAR-γ gene expression and improved SOD activity and inhibited MPO activity. The histological changes of the lungs were also significantly improved by formononetin compared to LPS group. The results indicated that formononetin has a protective effect on LPS-induced acute lung injury in mice.     

Role of T-Lymphocytes in the Resolution of Endotoxin-Induced Lung Injury

An acute neutrophilic lung injury was compared in Balb/c normal and nu/nu (nude) mice to assess the role of T lymphocytes in the resolution of acute pulmonary neutrophilic inflammation following the administration of endotoxin. Maximal neutrophilic infiltration occurred on day 1 post-endotoxin treatment and declined to near normal levels by day 5. In contrast, the percentage of lymphocytes in the bronchoalveolar lavage (BAL) fluid increased from 1.8% on day 1 post-endotoxin to greater than 11% on days three and five, during which time neutrophil resolution was occurring. On days 1–5 after endotoxin administration, approximately 40% of the CD4 lymphocytes expressed the cell surface activation marker, CD69. Despite being CD69⁺, CD4 cells did not express the high affinity IL-2 receptor chain, CD25, to any significant extent on any of the days studied. To assess the contribution of T cells to the rate of clearance of neutrophils from the BAL, normal and nude Balb/c mice were compared for the percentage of neutrophils following nasal administration of endotoxin. Endotoxin-treated nude mice did not demonstrate significant differences in either the total white blood cell counts or in the clearance of neutrophils from the BAL, as compared to normal Balb/c mice. These data indicate that the influx of activated T cells during the resolution of neutrophilic pneumonitis does not contribute to the rate of neutrophil clearance during acute lung injury.     

The Effects of Morin on Lipopolysaccharide-Induced Acute Lung Injury by Suppressing the Lung NLRP3 Inflammasome

In previous study, the anti-inflammatory effect of morin had been found. In this study, we investigated anti-inflammatory effects of morin on acute lung injury using lipopolysaccharide (LPS)-induced acute lung injury (ALI) mouse model. The cell counting in the bronchoalveolar lavage fluid (BALF) was measured. The animal lung edema degree was evaluated by wet/dry weight (W/D) ratio. The superoxidase dismutase (SOD) activity and myeloperoxidase (MPO) activity were assayed by SOD and MPO kits, respectively. The levels of inflammatory mediators including tumor necrosis factor-α (TNF-α), interleukin (IL)-1β, IL-18, and IL-6 were assayed by enzyme-linked immunosorbent assay method. Pathological changes of lung tissues were observed by hematoxylin and eosin (HE) staining. The protein level of lung NACHT, LRR, and PYD domains-containing protein 3 (NLRP3) inflammasome was measured by Western blotting. The data showed that treatment with the morin markedly attenuated inflammatory cell numbers in the BALF, decreased lung NLRP3 inflammasome protein level, and improved SOD activity and inhibited MPO activity. Histological studies demonstrated that morin substantially inhibited LPS-induced neutrophils in lung tissue compared with model group. The results indicated that the morin had a protective effect on LPS-induced ALI in mice.     

Galangin Dampens Mice Lipopolysaccharide-Induced Acute Lung Injury

Galangin, an active ingredient of Alpinia galangal, has been shown to possess anti-inflammatory and antioxidant activities. Inflammation and oxidative stress are known to play vital effect in the pathogenesis of acute lung injury (ALI). In this study, we determined whether galangin exerts lung protection in lipopolysaccharide (LPS)-induced ALI. Male BALB/c mice were randomized to receive galangin or vehicle intraperitoneal injection 3 h after LPS challenge. Samples were harvested 24 h post LPS administration. Galangin administration decreased biochemical parameters of oxidative stress and inflammation, and improved oxygenation and lung edema in a dose-dependent manner. These protective effects of galangin were associated with inhibition of nuclear factor (NF)-κB and upregulation of heme oxygenase (HO)-1. Galangin reduces LPS-induced ALI by inhibition of inflammation and oxidative stress.     

P38 MAPK抑制剂对急性肺损伤大鼠细胞间黏附分子-1表达的影响

目的观察P38 MAPK抑制剂预处理对脂多糖(LPS)致大鼠急性肺损伤(ALI)细胞间黏附分子-1(ICAM-1)的影响,探讨P38 MAPK抑制剂干预ALI的理论基础。方法腹腔内注射 气管内给LPS复制大鼠ALI模型,用免疫组化方法测定肺组织ICAM-1的表达。结果模型组和预处理组的ICAM-1表达显著高于对照组(P<0.01,P<0.05),且模型组高于预处理组(P<0.05)。结论P38MAPK抑制剂预处理可下调大鼠细胞黏附分子ICAM-1的表达,减轻肺组织的病理损害,能起到防治ALI的作用。     

Preferential Lymphatic Growth in Bronchus-Associated Lymphoid Tissue in Sustained Lung Inflammation

Lymphatics proliferate, become enlarged, or regress in multiple inflammatory lung diseases in humans. Lymphatic growth and remodeling is known to occur in the mouse trachea in sustained inflammation, but whether intrapulmonary lymphatics exhibit similar plasticity is unknown. We examined the time course, distribution, and dependence on vascular endothelial growth factor receptor (VEGFR)-2/VEGFR-3 signaling of lung lymphatics in sustained inflammation. Lymphatics in mouse lungs were examined under baseline conditions and 3 to 28 days after Mycoplasma pulmonis infection, using prospero heomeobox 1–enhanced green fluorescence protein and VEGFR-3 as markers. Sprouting lymphangiogenesis was evident at 7 days. Lymphatic growth was restricted to regions of bronchus-associated lymphoid tissue (BALT), where VEGF-C–producing cells were scattered in T-cell zones. Expansion of lung lymphatics after infection was reduced 68% by blocking VEGFR-2, 83% by blocking VEGFR-3, and 99% by blocking both receptors. Inhibition of VEGFR-2/VEGFR-3 did not prevent the formation of BALT. Treatment of established infection with oxytetracycline caused BALT, but not the lymphatics, to regress. We conclude that robust lymphangiogenesis occurs in mouse lungs after M. pulmonis infection through a mechanism involving signaling of both VEGFR-2 and VEGFR-3. Expansion of the lymphatic network is restricted to regions of BALT, but lymphatics do not regress when BALT regresses after antibiotic treatment. The lung lymphatic network can thus expand in sustained inflammation, but the expansion is not as reversible as the accompanying inflammation.Lymphatic vessels undergo changes in many inflammatory lung diseases, where lymphatic proliferation, enlargement, and regression have been described.^1,2 Examples include asthma, where lymphatics regress,³ chronic obstructive pulmonary disease (COPD) and pneumonia, where they proliferate,^4–6 and idiopathic pulmonary fibrosis, where they undergo abnormal growth and remodeling in the lung parenchyma^7,8 but regress in subpleural and interlobular compartments.⁹Although lymphatics are well known to drain interstitial fluid and serve as conduits for antigen-presenting cells and lymphocytes from the lung,^10–12 little has been learned about the mechanism and functional implications of lymphatic changes in pulmonary inflammation. Regardless of the impact of lymphangiogenesis on disease pathophysiological characteristics, the presence of edema in inflammatory lung disease indicates that the amount of plasma leakage exceeds the fluid drainage capacity through lymphatics and other routes.Lymphatics proliferate in many settings of sustained inflammation, including psoriasis,¹³ rheumatoid arthritis,¹⁴ and inflammatory bowel disease,¹⁵ but it is still unclear whether proliferation of lymphatics worsens or ameliorates disease severity. Promotion of lymphatic growth by transgenic overexpression of vascular endothelial growth factor (VEGF)-C reduces the severity of skin inflammation.¹⁶ This effect has not been examined in the lung, and it is unknown whether it is typical of inflammatory conditions in other organs. It is also unclear whether lung lymphatics exhibit the same plasticity in inflammation as those in other organs.Previous studies had shown that tracheal lymphatics undergo widespread growth and remodeling after infection. During the first 4 weeks after infection, tracheal lymphatics undergo even more extensive changes than blood vessels.^17,18 However, sensitization and challenge of lungs to house dust mite allergen for 2 weeks has no detectable effect on the number of lung lymphatics.¹⁹ Little is known about the effects on lung lymphatics of other conditions of sustained inflammation.We, therefore, used a mouse model of sustained lung inflammation produced by respiratory tract infection by Mycoplasma pulmonis bacteria to determine the response of lung lymphatics to sustained inflammation and to compare changes in the lung with those in the trachea. With the presumption that lymphangiogenesis does occur in the lung, we sought to determine exactly when and where. During the period of 1 to 4 weeks after infection, we closely observed the distribution of the changes in the lung to address the possibility that lymphatic growth or remodeling was regionally specific.We also investigated the driving mechanism for lymphatic growth in lungs in this model. Because of compelling evidence that lymphatic growth in the trachea and other settings is driven by VEGF-C activation of VEGF receptor (VEGFR)-3 signaling,²⁰ we compared the effects in the lung and trachea of blocking VEGFR-2 and VEGFR-3 administered individually or together.Consistent with this reasoning, previous studies revealed that lymphangiogenesis in the trachea after M. pulmonis infection was completely inhibited by a function-blocking antibody to VEGFR-3.¹⁷ Similar results have been obtained in skin²¹ and cornea.²² However, lymphangiogenesis under some conditions is also partially reduced by selective inhibition of VEGFR-2, examples being skin,²³ cornea,²⁴ lymph nodes,²⁵ arthritic joints,²⁴ and tumors.²⁶ The latter mechanism could reflect effects of VEGFR-2 blockade directly on lymphatics or indirectly through changes in leukocytes or other cells that produce lymphangiogenic factors.The present study of lymphatic remodeling in sustained bronchopneumonia produced by M. pulmonis infection addressed the question of whether lymphatics grow, undergo remodeling, or regress during the development of bronchopneumonia. The study also examined the time course of changes in lymphatics, whether the distribution of lymphangiogenesis coincides with the widespread inflammatory changes in the lung, and whether lymphatic growth and remodeling in the lung is driven by changes in signaling of VEGFR-3, VEGFR-2, or both.The experiments revealed that some lymphatics in the lung underwent profound changes after M. pulmonis infection. Sprouting lymphangiogenesis was evident at 1 week and was more pronounced at 2 and 4 weeks. Strikingly, expansion of the lymphatic network was restricted to regions of bronchus-associated lymphoid tissue (BALT) that formed in the lung around bronchi and major pulmonary vessels. Lymphatics in more peripheral regions of the lung did not exhibit these changes, despite the presence of inflammatory cells. Growth of lymphatics in BALT was blocked 99% by inhibition of VEGFR-2 and VEGFR-3 together. Inhibition of VEGFR-3 alone resulted in 83% reduction, whereas inhibition of VEGFR-2 alone resulted in 68% reduction. Inhibition of lymphangiogenesis in BALT by blocking VEGFR-2 and VEGFR-3 did not prevent the formation of BALT.