Chemokine receptor CXCR3 is important for lung tissue damage and airway remodeling induced by short-term exposure to cigarette smoking in mice

Aim:

To investigate the role of chemokine receptor CXCR3 in cigarette smoking (CS)-induced pulmonary damage.

Methods:

CXCR3 knockout (CXCR3-/-) mice were used. Differences in airspace enlargement, mRNA expression of matrix metalloproteinases (MMPs), transforming growth factor (TGF) β1, CXCL10 in lung homogenates, and CXCL10 content in bronchoalveolar lavage (BAL) fluids and homogenates were compared between CXCR3-/- mice and wild-type (WT) mice three days after three-day CS exposures.

Results:

The linear intercept was significantly less in CXCR3-/- mice than in WT mice (30.1±0.9 μm vs 40.3±2.4 μm, P<0.01). Morphologically, collagen was deposited less around airways and vessels in CXCR3-/- mice. The lung hydroxyproline content was significantly lower in CXCR3-/- mice than in WT mice (6.0±1.0 μg/mL vs 12.0±1.6 μg/mL, P<0.05). Profoundly lower mRNA expression of MMP2, MMP12, TGFβ1, and CXCL10 was seen in lung homogenates from CXCR3-/- mice. CXCL10 concentrations in BAL fluid and lung homogenates were significantly lower in CXCR3-/- mice than in WT mice (BAL fluid: 19.3±1.4 pg/mL vs 24.8±1.6 pg/mL, P<0.05; lung homogenates: 76.6±7.0 pg/mL vs 119.5±15.9 pg/mL, P<0.05).

Conclusion:

CXCR3 is important in mediating lung tissue damage and airway remodeling following a short-term CS insult, possibly through up-regulation of CXCL10 and inducement of mRNA expression of MMPs. Targeting CXCR3 may be helpful for prevention of CS-induced pulmonary pathology.     

The selective MMP-12 inhibitor, AS111793 reduces airway inflammation in mice exposed to cigarette smoke

BACKGROUND: Macrophage elastase (MMP-12) is involved in the inflammatory process of chronic obstructive pulmonary disease (COPD). The aim of this study was to investigate in mice the effect of MMP-12 inhibition on the inflammatory process induced by cigarette smoke (CS) or by lipopolysaccharide (LPS) exposure of the airways. EXPERIMENTAL APPROACH: C57BL/6 mice were given, orally, either the selective MMP-12 inhibitor AS111793 (3, 10, 30 and 100 mg kg(-1)), the PDE-4 inhibitor roflumilast (3 mg kg(-1)) or vehicle, then exposed to CS (for 3 days) or to LPS (100 microg mL(-1), 30 min). Subsequent to the last smoke or LPS exposure, bronchoalveolar lavages (BAL) were performed and lungs were removed and homogenized to analyze various markers of inflammation at appropriate times. KEY RESULTS: Inhibition of MMP-12 by AS111793 (10 and 30 mg kg(-1)) was associated with a reduction of the increase in neutrophil number in BAL fluids after 4 days and of macrophages after 11 days. On day 4, AS111793 also significantly reduced all the inflammation markers that had increased after CS exposure, including soluble TNF receptors I and II, MIP-1gamma, IL-6 and pro-MMP-9 activity in BAL fluids, and KC/CXCL1, fractalkine/CX3CL1, TIMP-1 and I-TAC/CXCL11 in lung parenchyma. In contrast, inhibition of MMP-12 did not reduce neutrophil influx, pro-MMP-9 activity or KC/CXCL1 release in BAL fluids of mice exposed to LPS. CONCLUSION: Inhibition of MMP-12 with AS111793, reduced the inflammatory process associated with exposure of mice to CS, strongly suggesting a specific involvement of MMP-12 in lung inflammation following CS exposure.     

Oxidative stress is an important component of airway inflammation in mice exposed to cigarette smoke or lipopolysaccharide

1. It was proposed previously that oxidative stress is a main component of the inflammatory process in chronic obstructive pulmonary disease (COPD). Thus, in the present study, we investigated the inflammatory response in mice deficient for the p47(phox) subunit of NADPH oxidase (p47 KO) exposed to cigarette smoke (CS). 2. Exposure of mice to CS elicited an increase in the number of macrophages and neutrophils and levels of interleukin (IL)-6, keratinocyte-derived chemokine (KC/CXCL1) and monocyte chemoattractant protein-1 (MCP1/CCL2) in bronchoalveolar lavage fluid (BALF), which were lower in p47 KO mice compared with control mice. In contrast, 24 h after lipopolysaccharide (LPS) exposure, the number of macrophages and neutrophils, as well as KC/CXCL1 levels, in BALF was significantly greater in p47 KO mice compared with control mice. 3. The present study has shown that airway inflammation is decreased in p47 KO mice after exposure to CS, but not LPS, suggesting that oxidative stress is involved in the pathogenesis of airway inflammation associated with COPD.     

羧甲司坦对香烟烟雾提取物诱导A549细胞炎性损伤的影响

目的：探讨羧甲司坦抑制香烟烟雾提取物（CSE）诱导A549细胞炎性损伤的作用。方法：传代培养人A549细胞并分为5组：对照组，CSE组，羧甲司坦低、中、高剂量组（予不同浓度羧甲司坦孵育和CSE诱导）。qRT-PCR、ELISA检测主要细胞因子的合成和释放，免疫蛋白印迹（Western-blot）、免疫荧光（IF）观察NF-κB及MAPK相关信号通路的活化情况。结果：以羧甲司坦预处理或后处理，均可降低CSE诱导的A549细胞的IL-6、IL-8和MIP-1β mRNA的表达；降低IL-6及IL-8的释放。羧甲司坦预处理可抑制p65入核。Western-blot结果显示，对照组，CSE组，羧甲司坦低、中、高剂量组的P-p65蛋白相对表达量分别为（0.17±0.05）、（0.90±0.19）、（0.68±0.15）、（0.64±0.12）和（0.57±0.13），pERK1/2蛋白相对表达量分别为（0.30±0.10）、（1.25±0.33）、（1.01±0.19）、（0.89±0.22）和（0.81±0.18），CSE组均明显高于对照组，羧甲司坦低、中、高剂量组均明显低于CSE组（P<0.05）。结论：羧甲司坦通过抑制NF-κB p65及ERK1/2 MAPK活化，发挥对CSE诱导的A549细胞炎性损伤的保护作用。     

Interleukin-1β: A possible mediator of lung inflammation and airway hyperreactivity

Interleukin-1 (IL-1), a peptide released from monocytes/macrophages, plays an important role in the inflammatory and immune responses. Airway hyperreactivity and the underlying airway inflammation are common features in asthma pathology. We investigated and characterized the inflammatory alterations induced within the guinea-pig respiratory system by IL-1 beta. Injection of IL-1 beta (1-6 micrograms/animal) into the pleural space resulted in a dose-dependent inflammatory response, as shown by the formation of pleural exudate and leucocyte recruitment. A threshold dose of IL-1 beta (1 micrograms/animal) markedly potentiated the inflammatory reaction triggered by the classical proinflammatory agent croton oil, underlining the amplifying role of IL-1 beta in the inflammatory events. The inflammatory process induced by intrapleural injection of IL-1 beta (6 micrograms/animal) was associated with the development of a hyperreactive phenomenon which involved both the peripheral and large airways. In fact, increased contractile activity of histamine was evident in the tracheas and parenchymal strips isolated from guinea-pigs exposed to IL-1 beta. These results provide evidence for a possible role of IL-1 beta in the genesis of airway inflammation and bronchial hyperreactivity.     

牛蒡子苷元通过SIRT1/NLRP3途径减轻哮喘小鼠气道炎症

目的探讨牛蒡子苷元对哮喘小鼠模型中对气道炎症的疗效以及其机制是否与SIRT1/NLRP3信号通路有关。方法选取40只♀清洁级BALB/c小鼠,分为control组,OVA模型组,ATG组(5、10和20 mg·kg^-1)。HE及PAS染色法观察肺组织病理改变;Diff-Quick染色法对小鼠BALF中细胞分类及计数;流式细胞术测定小鼠肺组织中细胞因子在CD4阳性细胞群中的阳性比例;Western blot测定肺组织SIRT1、NLRP3、caspase-1、IL-18和IL-1β蛋白表达;免疫荧光法检测小鼠肺组织中NLRP3荧光强度。结果牛蒡子苷元能抑制OVA诱导的炎症细胞的渗出及杯状细胞增生;牛蒡子苷元抑制小鼠肺泡灌洗液中总细胞数及NEU、EOS、LYM的生成,并升高肺组织中IFN-γ水平的同时降低IL-4的水平;Western blot结果显示,牛蒡子苷元增加SIRT1蛋白表达同时抑制NLRP3、caspase-1、IL-18和IL-1β蛋白表达;免疫荧光结果显示,牛蒡子苷元可以减弱肺组织NLRP3的荧光强度。结论牛蒡子苷元通过SIRT1/NLRP3途径减轻哮喘小鼠气道炎症。     

The kinetics of transcriptomic changes induced by cigarette smoke in rat lungs reveals a specific program of defense, inflammation, and circadian clock gene expression.

Gene expression profiling in animal models exposed to cigarette mainstream smoke (CS) shapes up as a promising tool for investigating the molecular mechanisms involved in the onset and development of CS-related disease and may aid in the identification of disease candidate genes. Here we report on differential gene expression in lungs of rats exposed for 2, 7, and 13 weeks to 300 and 600 microg total particulate matter/l CS with sacrifice 2, 6, or 20 h after the last exposure. Regarding antioxidant and xenobiotic-metabolizing (phase I/II) enzymes, a stereotypic, mostly transient, expression pattern of differentially expressed genes was observed after each exposure period. The expression patterns were generally dose dependent for antioxidant and phase II genes and not dose dependent for phase I genes at the CS concentrations tested. However, with increasing length of exposure, there was a distinct, mostly sustained and dose-sensitive, expression of genes implicated in innate and adaptive immune responses, clearly pointing to an emerging inflammatory response. Notably, this inflammatory response included the expression of lung disease-related genes not yet linked to CS exposure, such as galectin-3, arginase 1, and chitinase, as well as genes encoding proteolytic enzymes. Finally, our experiments also revealed a CS exposure-dependent shift in the cyclical expression of genes involved in controlling the circadian rhythm. Altogether, these results provide further insight into the molecular mechanisms of CS-dependent disease onset and development and thus may also be useful for defining CS-specific molecular biomarkers of disease.     

Tanshinone IIA therapeutically reduces LPS-induced acute lung injury by inhibiting inflammation and apoptosis in mice

Aim:

To study the effects of tanshinone IIA (TIIA) on lipopolysaccharide (LPS)-induced acute lung injury in mice and the underlying mechanisms.

Methods:

Mice were injected with LPS (10 mg/kg, ip), then treated with TIIA (10 mg/kg, ip). Seven hours after LPS injection, the lungs were collected for histological study. Protein, LDH, TNF-α and IL-1β levels in bronchoalveolar lavage fluid (BALF) and myeloperoxidase (MPO) activity in lungs were measured. Cell apoptosis and Bcl-2, caspase-3, NF-κB and HIF-1α expression in lungs were assayed.

Results:

LPS caused marked histological changes in lungs, accompanied by significantly increased lung W/D ratio, protein content and LDH level in BALF, and Evans blue leakage. LPS markedly increased neutrophil infiltration in lungs and inflammatory cytokines in BALF. Furthermore, LPS induced cell apoptosis in lungs, as evidenced by increased TUNEL-positive cells, decreased Bcl-2 content and increased cleaved caspase-3 content. Moreover, LPS significantly increased the expression of NF-κB and HIF-1α in lungs. Treatment of LPS-injected mice with TIIA significantly alleviated these pathological changes in lungs.

Conclusion:

TIIA alleviates LPS-induced acute lung injury in mice by suppressing inflammatory responses and apoptosis, which is mediated via inhibition of the NF-κB and HIF-1α pathways.     

Pristimerin protects against inflammation and metabolic disorder in mice through inhibition of NLRP3 inflammasome activation

Excessive activation of NLRP3 inflammasome is associated with the pathogenesis of inflammatory diseases. Pristimerin (Pri) is a quinonoid triterpene derived from traditional Chinese medical herb Celastraceae and Hippocrateaceae. Pri has shown antifungal, antibacterial, antioxidant, and anticancer activities. In this study we investigated whether NLRP3 inflammasome was associated with the anti-inflammatory activity of Pri. We showed that Pri (0.1−0.4 μM) dose-dependently blocked caspase-1 activation and IL-1β maturation in LPS-primed mouse bone-marrow-derived macrophages (BMDMs). Pri specifically inhibited NLRP3 inflammasome activation, had no visible effects on NLRC4 and AIM2 inflammasome activation. Furthermore, we demonstrated that Pri blocked the assembly of the NLRP3 inflammasome via disturbing the interaction between NEK7 and NLRP3; the α, β-unsaturated carbonyl moiety of Pri was essential for NLRP3 inflammasome inactivation. In LPS-induced systemic inflammation mouse model and MSU-induced mouse peritonitis model, preinjection of Pri (500 μg/kg, ip) produced remarkable therapeutic effects via inhibition of NLRP3 inflammasome in vivo. In HFD-induced diabetic mouse model, administration of Pri (100 μg· kg⁻¹ ·d⁻¹, ip, for 6 weeks) reversed HFD-induced metabolic disorders via suppression of NLRP3 inflammasome activation. Taken together, our results demonstrate that Pri acts as a NLRP3 inhibitor, suggesting that Pri might be useful for the treatment of NLRP3-associated diseases.     

Regulation of ozone‐induced lung inflammation by the epidermal growth factor receptor in mice

Human exposure to the highly reactive oxidant gas Ozone (O₃) is associated with inflammatory responses in the airway epithelium. The mechanisms responsible have not been fully elucidated. Epidermal growth factor receptor (EGFR) has previously been shown to play a critical role in the pathogenesis of lung inflammation. To define the role of EGFR in O₃‐induced lung inflammation in mice. 40 BALB/c mice were exposed to filtered air (FA) or (0.25, 0.5, 1.00 ppm) O₃ for 3 h per day for 7 consecutive days. Levels of reactive oxygen species (ROS), EGF, and transforming growth factor α (TGF‐α) in the bronchoalveolar lavage fluid (BALF) of mice were measured using ELISA. BALB/c mice were intratracheally instilled with the EGFR kinase inhibitor PD153035 2 h prior to O₃ exposure and every other day thereafter. Phosphorylation of EGFR (Y1068) in lung sections was determined using immunohistochemical staining and western blot 24 h after exposure. Inhalation of O₃ induced pronounced lung inflammation in a dose‐dependent manner. Levels of ROS, TGF‐α, and total proteins and cells in the BALF of mice exposed to 0.5 ppm or 1.0 ppm of O₃ were markedly elevated relative to those in the BALF of the mice exposed to FA. In addition, exposure to O₃ induced EGFR(Y1068) phosphorylation in the airway epithelium. Administration of PD153035 resulted in a significantly reduced lung inflammation as well as EGFR phosphorylation induced by O₃ exposure. Inhalation of O₃ leads to inflammatory responses that are dependent on the activation the EGFR in the airway epithelium. © 2015 Wiley Periodicals, Inc. Environ Toxicol 31: 2016–2027, 2016.     

组蛋白修饰变化参与曲古抑菌素A缓解的烟草烟雾暴露所致小鼠子宫损伤过程

目的研究组蛋白修饰变化在曲古抑菌素A(trichostatin A,TSA)缓解烟草烟雾(cigarette smoke,CS)暴露所致的雌性小鼠子宫损伤过程中的作用。方法通过CS暴露30 d方法制备CS暴露小鼠子宫损伤模型,CS暴露的同时给予TSA进行治疗;HE染色观察各组小鼠子宫组织形态学变化;Western blot技术检测各组小鼠子宫组织H3K4me1、H3K4me2、H3K4me3、H3K9me1、H3K9me2、H3K9me3和H3K27me3总的修饰水平变化以及GLP(euchromatic histone lysine methyltransferase 1,H3K9甲基转移酶),G9ɑ(euchromatic histone lysine methyltransferase 2,H3K9甲基转移酶),EZH2(enhancer of zeste homolog 2,H3K27me3甲基转移酶)的表达水平。结果TSA缓解CS暴露所致的雌性小鼠子宫间质细胞和腺体数量减少等结构改变。TSA有效抑制了CS暴露激活的小鼠子宫组织H3K9me1的表达,但却进一步激活CS暴露诱导的总H3K27me3修饰水平。TSA可以抑制CS暴露激活的小鼠子宫组织GLP和G9ɑ的表达,进一步激活CS暴露诱导的EZH2表达水平。结论组蛋白修饰变化参与CS暴露所致的小鼠子宫损伤以及TSA的缓解损伤过程。     

Etanercept prevents airway hyperresponsiveness by protecting neuronal M2 muscarinic receptors in antigen-challenged guinea pigs

Background and purpose

Increased tumour necrosis factor-α (TNF-α) is associated with airway hyperreactivity in antigen-challenged animals. In human asthmatics, TNF-α is increased and blocking it prevents airway hyperreactivity in some asthmatic patients. However, the mechanisms by which TNF-α mediates hyperreactivity are unknown. Airway hyperreactivity can be caused by dysfunction of neuronal M₂ muscarinic receptors that normally limit acetylcholine release from parasympathetic nerves. Here we test whether blocking TNF-α receptors with etanercept prevents M₂ receptor dysfunction and airway hyperreactivity in antigen-challenged guinea pigs.

Experimental approach

Ovalbumin-sensitized guinea pigs were challenged by inhalation of antigen. Some animals received etanercept (3 mg kg⁻¹ i.p.) 3 h before challenge. 24 h after challenge, airway hyperreactivity and M₂ receptor function were tested. Inflammatory cells in bronchoalveolar lavage, blood and lung were counted. TNF-α and its receptors were detected by real-time RT-PCR and immunocytochemistry in parasympathetic nerves from humans and guinea pigs and in human neuroblastoma cells.

Key results

Antigen-challenged animals were hyperreactive to vagal stimulation and neuronal M₂ receptors were dysfunctional. Both M₂ receptor dysfunction and airway hyperreactivity were prevented by etanercept. Etanercept reduced eosinophils around airway nerves, and in blood, bronchoalveolar lavage and airway smooth muscle. Also, TNF-α decreased M₂ receptor mRNA in human and guinea pig parasympathetic neurons.

Conclusions and implications

Tumour necrosis factor-α may contribute to M₂ receptor dysfunction and airway hyperreactivity directly by decreasing receptor expression and indirectly by promoting recruitment of eosinophils, containing major basic protein, an M₂ antagonist. This suggests that etanercept may be beneficial in treatment of allergic asthma.     

Plasminogen-stimulated airway smooth muscle cell proliferation is mediated by urokinase and annexin A2, involving plasmin-activated cell signalling

BACKGROUND AND PURPOSE

The conversion of plasminogen into plasmin by interstitial urokinase plasminogen activator (uPA) is potentially important in asthma pathophysiology. In this study, the effect of uPA-mediated plasminogen activation on airway smooth muscle (ASM) cell proliferation was investigated.

EXPERIMENTAL APPROACH

Human ASM cells were incubated with plasminogen (0.5–50 μg·mL⁻¹) or plasmin (0.5–50 mU·mL⁻¹) in the presence of pharmacological inhibitors, including UK122, an inhibitor of uPA. Proliferation was assessed by increases in cell number or MTT reduction after 48 h incubation with plasmin(ogen), and by earlier increases in [³H]-thymidine incorporation and cyclin D1 expression.

KEY RESULTS

Plasminogen (5 μg·mL⁻¹)-stimulated increases in cell proliferation were attenuated by UK122 (10 μM) or by transfection with uPA gene-specific siRNA. Exogenous plasmin (5 mU·mL⁻¹) also stimulated increases in cell proliferation. Inhibition of plasmin-stimulated ERK1/2 or PI3K/Akt signalling attenuated plasmin-stimulated increases in ASM proliferation. Furthermore, pharmacological inhibition of cell signalling mediated by the EGF receptor, a receptor trans-activated by plasmin, also reduced plasmin(ogen)-stimulated cell proliferation. Knock down of annexin A2, which has dual roles in both plasminogen activation and plasmin-signal transduction, also attenuated ASM cell proliferation following incubation with either plasminogen or plasmin.

CONCLUSIONS AND IMPLICATIONS

Plasminogen stimulates ASM cell proliferation in a manner mediated by uPA and involving multiple signalling pathways downstream of plasmin. Targeting mediators of plasminogen-evoked ASM responses, such as uPA or annexin A2, may be useful in the treatment of asthma.     

Inhibiting glycogen synthase kinase-3 reduces endotoxaemic acute renal failure by down-regulating inflammation and renal cell apoptosis

Background and purpose:

Excessive inflammation and apoptosis are pathological features of endotoxaemic acute renal failure. Activation of glycogen synthase kinase-3 (GSK-3) is involved in inflammation and apoptosis. We investigated the effects of inhibiting GSK-3 on lipopolysaccharide (LPS)-induced acute renal failure, nuclear factor-κB (NF-κB), inflammation and apoptosis.

Experimental approach:

The effects of inhibiting GSK-3 with inhibitors, including lithium chloride (LiCl) and 6-bromo-indirubin-3′-oxime (BIO), on LPS-treated (15 mg·kg⁻¹) C3H/HeN mice (LiCl, 40 mg·kg⁻¹ and BIO, 2 mg·kg⁻¹) and LPS-treated (1 µg·mL⁻¹) renal epithelial cells (LiCl, 20 mM and BIO, 5 µM) were studied. Mouse survival was monitored and renal function was analysed by histological and serological examination. Cytokine and chemokine production, and cell apoptosis were measured by enzyme-linked immunosorbent assay and terminal deoxynucleotidyl transferase-mediated dUTP–biotin nick-end labelling staining, respectively. Activation of NF-κB and GSK-3 was determined by immunostaining and Western blotting, respectively.

Key results:

Mice treated with GSK-3 inhibitors showed decreased mortality, renal tubular dilatation, vacuolization and sloughing, blood urea nitrogen, creatinine and renal cell apoptosis in response to endotoxaemia. Inhibiting GSK-3 reduced LPS-induced tumour necrosis factor-α (TNF-α) and CCL5/RANTES (released upon activation of normal T-cells) in vivo in mice and in vitro in murine kidney cortical collecting duct epithelial M1 cells. Inhibiting GSK-3 did not block TNF-α-induced cytotoxicity in rat kidney proximal tubular epithelial NRK52E or in M1 cells.

Conclusions and implications:

These results suggest that GSK-3 inhibition protects against endotoxaemic acute renal failure mainly by down-regulating pro-inflammatory TNF-α and RANTES.     

Mzb1 protects against myocardial infarction injury in mice via modulating mitochondrial function and alleviating inflammation

Myocardial infarction (MI) leads to the loss of cardiomyocytes, left ventricle dilation and cardiac dysfunction, eventually developing into heart failure. Mzb1 (Marginal zone B and B1 cell specific protein 1) is a B-cell-specific and endoplasmic reticulum-localized protein. Mzb1 is an inflammation-associated factor that participates a series of inflammatory processes, including chronic periodontitis and several cancers. In this study we investigated the role of Mzb1 in experimental models of MI. MI was induced in mice by ligation of the left descending anterior coronary artery, and in neonatal mouse ventricular cardiomyocytes (NMVCs) by H₂O₂ treatment in vitro. We showed that Mzb1 expression was markedly reduced in the border zone of the infarct myocardium of MI mice and in H₂O₂-treated NMVCs. In H₂O₂-treated cardiomyocytes, knockdown of Mzb1 decreased mitochondrial membrane potential, impaired mitochondrial function and promoted apoptosis. On contrary, overexpression of Mzb1 improved mitochondrial membrane potential, ATP levels and mitochondrial oxygen consumption rate (OCR), and inhibited apoptosis. Direct injection of lentiviral vector carrying Len-Mzb1 into the myocardial tissue significantly improved cardiac function and alleviated apoptosis in MI mice. We showed that Mzb1 overexpression significantly decreased the levels of Bax/Bcl-2 and cytochrome c and improved mitochondrial function in MI mice via activating the AMPK-PGC1α pathway. In addition, we demonstrated that Mzb1 recruited the macrophages and alleviated inflammation in MI mice. We conclude that Mzb1 is a crucial regulator of cardiomyocytes after MI by improving mitochondrial function and reducing inflammatory signaling pathways, implying a promising therapeutic target in ischemic cardiomyopathy.     

Subchronic effects of perfluorooctanesulfonate exposure on inflammation in adult male C57BL/6 mice

Previous studies indicate that exposure to perfluorooctanesulfonate (PFOS), a ubiquitous and highly persistent environmental contaminant, induces immunotoxicity in mice. However, few studies have specifically assessed the effects of PFOS on inflammation. This study utilized a standard 60‐day oral exposure period to assess the effects of PFOS on the response of inflammatory cytokines [tumor necrosis factor α (TNF‐α), interleukin‐1 β (IL‐1β), and interleukin‐6 (IL‐6)]. Adult male C57BL/6 mice were dosed daily by oral gavage with PFOS at 0, 0.0083, 0.0167, 0.0833, 0.4167, 0.8333 or 2.0833 mg/kg/day to yield a targeted Total Administered Dose (TAD) over 60 days of 0, 0.5, 1, 5, 25, 50, or 125 mg PFOS/kg, respectively. The percentage of peritoneal macrophages (CD11b⁺ cells) was significantly increased at concentrations ≥1 mg PFOS/kg TAD in a dose‐dependent manner. Ex vivo IL‐1β production by peritoneal macrophages was elevated substantially at concentrations of ≥5 mg PFOS/kg TAD. Moreover, PFOS exposure markedly enhanced the ex vivo production of TNF‐α, IL‐1β and IL‐6 by peritoneal and splenic macrophages when stimulated either in vitro or in vivo with lipopolysaccharide (LPS). The serum levels of these inflammatory cytokines observed in response to in vivo stimulation with LPS were elevated substantially by exposure to PFOS. PFOS exposure elevated the expression of pro‐inflammatory cytokines TNF‐α, IL‐1β, IL‐6, and proto‐oncogene, c‐myc, in the spleen. These data suggest that exposure to PFOS modulates the inflammatory response, and further research is needed to determine the mechanism of action. © 2010 Wiley Periodicals, Inc. Environ Toxicol, 2012.     

Deletion of thioredoxin-interacting protein preserves retinal neuronal function by preventing inflammation and vascular injury

BACKGROUND AND PURPOSE

Retinal neurodegeneration is an early and critical event in several diseases associated with blindness. Clinically, therapies that target neurodegeneration fail. We aimed to elucidate the multiple roles by which thioredoxin-interacting protein (TXNIP) contributes to initial and sustained retinal neurodegeneration.

EXPERIMENTAL APPROACH

Neurotoxicity was induced by intravitreal injection of NMDA into wild-type (WT) and TXNIP-knockout (TKO) mice. The expression of apoptotic and inflammatory markers was assessed by immunohistochemistry, elisa and Western blot. Microvascular degeneration was assessed by periodic acid-Schiff and haematoxylin staining and retinal function by electroretinogram.

KEY RESULTS

NMDA induced early (1 day) and significant retinal PARP activation, a threefold increase in TUNEL-positive nuclei and 40% neuronal loss in ganglion cell layer (GCL); and vascular permeability in WT but not TKO mice. NMDA induced glial activation, expression of TNF-α and IL-1β that co-localized with Müller cells in WT but not TKO mice. In parallel, NMDA triggered the expression of NOD-like receptor protein (NLRP3), activation of caspase-1, and release of IL-1β and TNF-α in primary WT but not TKO Müller cultures. After 14 days, NMDA induced 1.9-fold microvascular degeneration, 60% neuronal loss in GCL and increased TUNEL-labelled cells in the GCL and inner nuclear layer in WT but not TKO mice. Electroretinogram analysis showed more significant reductions in b-wave amplitudes in WT than in TKO mice.

CONCLUSION AND IMPLICATIONS

Targeting TXNIP expression prevented early retinal ganglion cell death, glial activation, retinal inflammation and secondary neuro/microvascular degeneration and preserved retinal function. TXNIP is a promising new therapeutic target for retinal neurodegenerative diseases.     

Co-delivery of ccl19 gene enhances anti-caries DNA vaccine pCIA-P immunogenicity in mice by increasing dendritic cell migration to secondary lymphoid tissues

Aim:

To investigate how co-delivery of the gene encoding C–C chemokine ligand-19 (CCL-19) affected the systemic immune responses to an anti-caries DNA vaccine pCIA-P in mice.

Methods:

Plasmid encoding CCL19-GFP fusion protein (pCCL19/GFP) was constructed by inserting murine ccl19 gene into GFP-expressing vector pAcGFP1-N1. Chemotactic effect of the fusion protein on murine dendritic cells (DCs) was assessed in vitro and in vivo using transwell and flow cytometric analysis, respectively. BALB/c mice were administered anti-caries DNA vaccine pCIA-P plus pCCL19/GFP (each 100 μg, im) or pCIA-P alone. Serum level of anti-PAc IgG was assessed with ELISA. Splenocytes from the mice were stimulated with PAc protein for 48 h, and IFN-γ and IL-4 production was measured with ELISA. The presence of pCCL19/GFP in spleen and draining lymph nodes was assessed using PCR. The expression of pCCL19/GFP protein in these tissues was analyzed under microscope and with flow cytometry.

Results:

The expression level of CCL19-GFP fusion protein was considerably increased 48 h after transfection of COS-7 cells with pCCL19/GFP plasmids. The fusion protein showed potent chemotactic activity on DCs in vitro. The level of serum PAc-specific IgG was significantly increased from 4 to 14 weeks in the mice vaccinated with pCIA-P plus pCCL19/GFP. Compared to mice vaccinated with pCIA-P alone, the splenocytes from mice vaccinated with pCIA-P plus pCCL19/GFP produced significantly higher level of IFN-γ, but IL-4 production had no significant change. Following intromuscular co-delivery, pCCL19/GFP plasmid and fusion protein were detected in the spleen and draining lymph nodes. Administration of CCL19 gene in mice markedly increased the number of mature DCs in secondary lymphoid tissues.

Conclusion:

CCL19 serves as an effective adjuvant for anti-caries DNA vaccine by inducing chemotactic migration of DCs to secondary lymphoid tissues.     

The role of interleukin-6 in pulmonary inflammation and injury induced by exposure to environmental air pollutants.

This study was designed to examine the role of the cytokine interleukin-6 (IL-6) in environmental air pollutant-induced pulmonary inflammation, injury, and repair. IL-6 knockout (KO) mice and wild-type (WT) mice were exposed to filtered air; aged and diluted cigarette smoke (ADSS), a surrogate for environmental tobacco smoke; ozone; or ADSS followed by ozone (ADSS/ozone). The proportion of monocytes and neutrophils recovered by bronchoalveolar lavage (BAL) as well as the level of total protein in BAL fluid were significantly increased in both IL-6 KO and WT mice following exposure to ozone or to ADSS/ozone. However, bromodeoxyuridine (BrdU) labeling within terminal bronchiolar epithelium and proximal alveolar regions in IL-6 KO mice exposed to ozone or to ADSS/ozone was significantly reduced compared with IL-6 sufficient mice (WT). WT mice treated with IL-6 antibodies also demonstrated a reduction in BrdU cell labeling similar to that observed in IL-6 KO mice following exposure to ozone or ADSS/ozone. Clara cell secretory protein (CCSP) abundance, a marker of Clara cell maturation and function, was markedly reduced in the terminal bronchiolar epithelium of WT mice following exposure to ADSS and/or ozone, whereas CCSP abundance was unchanged in IL-6 KO mice. We conclude that endogenous IL-6 in mice plays a critical role in the progress of lung inflammation/injury, but CCSP may also play a role to protect the lungs of mice exposed to toxic air pollutants. Data from this study further suggest that IL-6 antibody treatment modalities may be a means to attenuate pulmonary inflammation and injury.