Aeroallergen-induced eosinophilic inflammation, lung damage, and airways hyperreactivity in mice can occur independently of IL-4 and allergen-specific immunoglobulins.

In this investigation we have used a mouse model containing certain phenotypic characteristics consistent with asthma and IL-4- and CD40-deficient mice to establish the role of this cytokine and allergen-specific immunoglobulins in the initiation of airways hyperreactivity and morphological changes to the airways in responses to aeroallergen challenge. Sensitization and aerosol challenge of mice with ovalbumin resulted in a severe airways inflammatory response which directly correlated with the induction of extensive airways damage and airways hyperreactivity to beta-methacholine. Inflammatory infiltrates were primarily characterized by the presence of CD4+ T cells and eosinophils. In IL-4-deficient mice, the recruitment of airways eosinophils was impaired, but not abolished in response to aeroallergen. Moreover, the characteristic airways damage and hyperreactivity normally resulting from allergen inhalation were not attenuated. Induction of these structural and functional changes to the airways occurred in the absence of ovalbumin-specific IgE and IgG1, but IgG2a and IgG3 were detected in the sera of IL-4-deficient mice. CD4+ T cells isolated from both wild-type and IL-4-deficient mice given ovalbumin produced significant levels of IL-5 after in vitro stimulation. Treatment of IL-4-deficient mice with anti-IL-5 mAb before aeroallergen challenge abolished blood and airways eosinophilia, lung damage, and airways hyperreactivity. These results indicate that IL-4 is not essential for the development of IL-5-producing CD4+ T cells or for the induction of eosinophilic inflammation and airways damage and hyperreactivity. In response to sensitization and aerosol challenge, CD40-deficient mice did not produce ovalbumin-specific IgE, IgG isotypes, or IgA, and airways inflammation and hyperreactivity were not attenuated. Our results suggest that allergic airways disease can occur via pathways which operate independently of IL-4 and allergen-specific immunoglobulins. Activation of these pathways is intimately associated with IL-5 and eosinophilic inflammation. Such pathways may play a substantive role in the etiology of asthma.     

Circulating, but not local lung, IL-5 is required for the development of antigen-induced airways eosinophilia.

IL-5 is induced locally in the lung and systemically in the circulation during allergic airways eosinophilic inflammation both in humans and experimental animals. However, the precise role of local and systemic IL-5 in the development of allergic airways eosinophilia remains to be elucidated. In our current study, we demonstrate that compared with their IL-5(+/+) counterparts, IL-5(-/-) mice lacked an IL-5 response both in the lung and peripheral blood, yet they released similar amounts of IL-4, eotaxin, and MIP-1alpha in the lung after ovalbumin (OVA) sensitization and challenge. At cellular levels, these mice failed to develop peripheral blood and airways eosinophilia while the responses of lymphocytes, neutrophils, and macrophages remained similar to those in IL-5(+/+) mice. To dissect the relative role of local and systemic IL-5 in this model, we constructed a gene transfer vector expressing murine IL-5. Intramuscular IL-5 gene transfer to OVA-sensitized IL-5(-/-) mice led to raised levels of IL-5 compartmentalized to the circulation and completely reconstituted airways eosinophilia upon OVA challenge, which was associated with reconstitution of eosinophilia in the bone marrow and peripheral blood. Significant airways eosinophilia was observed for at least 7 d in these mice. In contrast, intranasal IL-5 gene transfer, when rendered to give rise to a significant but compartmentalized level of transgene protein IL-5 in the lung, was unable to reconstitute airways eosinophilia in OVA-sensitized IL-5(-/-) mice upon OVA-challenge, which was associated with a lack of eosinophilic responses in bone marrow and peripheral blood. Our findings thus provide unequivocal evidence that circulating but not local lung IL-5 is critically required for the development of allergic airways eosinophilia. These findings also provide the rationale for developing strategies to target circulating IL-5 and/or its receptors in bone marrow to effectively control asthmatic airways eosinophilia.     

Intrinsic defect in T cell production of interleukin (IL)-13 in the absence of both IL-5 and eotaxin precludes the development of eosinophilia and airways hyperreactivity in experimental asthma

Interleukin (IL)-5 and IL-13 are thought to play key roles in the pathogenesis of asthma. Although both cytokines use eotaxin to regulate eosinophilia, IL-13 is thought to operate a separate pathway to IL-5 to induce airways hyperreactivity (AHR) in the allergic lung. However, identification of the key pathway(s) used by IL-5 and IL-13 in the disease process is confounded by the failure of anti-IL-5 or anti-IL-13 treatments to completely inhibit the accumulation of eosinophils in lung tissue. By using mice deficient in both IL-5 and eotaxin (IL-5/eotaxin(-/-)) we have abolished tissue eosinophilia and the induction of AHR in the allergic lung. Notably, in mice deficient in IL-5/eotaxin the ability of CD4(+) T helper cell (Th)2 lymphocytes to produce IL-13, a critical regulator of airways smooth muscle constriction and obstruction, was significantly impaired. Moreover, the transfer of eosinophils to IL-5/eotaxin(-/-) mice overcame the intrinsic defect in T cell IL-13 production. Thus, factors produced by eosinophils may either directly or indirectly modulate the production of IL-13 during Th2 cell development. Our data show that IL-5 and eotaxin intrinsically modulate IL-13 production from Th2 cells and that these signaling systems are not necessarily independent effector pathways and may also be integrated to regulate aspects of allergic disease.     

Cyclin-dependent kinase inhibition reduces lung damage in a mouse model of ventilator-induced lung injury

Mechanical ventilation (MV) has the potential to induce lung damage in healthy lungs or aggravate existing lung injury. Polymorphonuclear neutrophil (PMN) recruitment plays an important role in driving the inflammatory response in ventilator-induced lung injury (VILI). The cyclin-dependent kinase inhibitor r-roscovitine has been shown to induce apoptosis in PMNs. In this study, we investigated the potential of r-roscovitine treatment in reducing lung damage in a mouse model of VILI. Mice were tracheotomized and subjected to lung-protective MV with lower (～7.5 mL/kg) or lung-injurious MV with higher (～15 mL/kg) tidal volume (VT). R-roscovitine treatment enhanced apoptosis in PMNs in vitro. Ventilator-induced lung injury was associated with pulmonary PMN influx in low and high VT MV. During lung-injurious MV, r-roscovitine treatment reduced the number of PMNs and lowered levels of the lung damage markers RAGE (receptor for advanced glycation end products) and total immunoglobulin M in bronchoalveolar lavage fluid. R-roscovitine did not affect cytokine or chemokine levels in the bronchoalveolar space, neither during lung-protective nor lung-injurious MV. Thus, r-roscovitine treatment reduces lung damage in VILI, possibly dependent on increased apoptosis of PMNs.     

Interleukin 1 receptor antagonist reduces lethality and intestinal toxicity of 5-fluorouracil in a mouse mucositis model

Chemotherapy-induced intestinal mucositis is still an unmet medical problem. 5-Fluorouracil (5-Fu), a chemotherapy drug, was used to create the animal model of mucositis. Global gene expression array was applied to identify genetic signals involved in the pathogenesis of mucositis. Interleukin 1 receptor antagonist (IL-1Ra) was one of the candidates with the characteristic gene expression profile. Its temporal expression pattern correlated to the damage and regeneration phase of the small intestine after a single injection of 5-Fu to mice. Administration of recombinant IL-1Ra to the mouse model of intestinal mucositis induced by 5-Fu demonstrated its therapeutic effects to the symptoms and pathology of the disease. The IL-1Ra treatment reduced the acute lethality, accelerated their body weight recovery, and eliminated severe diarrhea. The symptomatic benefits were supported by the pathological benefits, in which the mice treated with IL-1Ra had less damage and faster recovery of the structure integrity of their small intestine than that of the mice treated with vehicle control. To deliver the therapeutics to the unmet medical condition, further mechanism and translational studies of IL-1Ra in the settings of chemotherapy-induced intestinal mucositis are warranted.     

Interleukin 1 receptor antagonist reduces lethality and intestinal toxicity of 5-Fluorouracil in a mouse mucositis model

Chemotherapy induced intestinal mucositis is still an unmet medical problem. 5-fluorouracil (5-Fu), a chemotherapy drug, was used to create the animal model of mucositis. Global gene expression array was applied to identify genetic signals involved in the pathogenesis of mucositis. Interleukin 1 receptor antagonist (IL-1Ra) was one of the candidates with the characteristic gene expression profile. Its temporal expression pattern correlated to the damage and regeneration phase of the small intestine after a single injection of 5-Fu to mice. Administration of recombinant IL-1Ra to the mouse model of intestinal mucositis induced by 5-Fu demonstrated its therapeutic effects to the symptoms and pathology of the disease. The IL-1Ra treatment reduced the acute lethality, accelerated their body weight recovery, and eliminated severe diarrhea. The symptomatic benefits were supported by the pathological benefits, in which the mice treated with IL-1Ra has less damage and faster recovery of the structure integrity of their small intestine than that of the mice treated with vehicle control. To deliver the therapeutics to the unmet medical condition, further mechanism and translational studies of IL-1Ra in the settings of chemotherapy induced intestinal mucositis are warranted.     

Notch基因在支气管哮喘模型小鼠肺中的表达

目的:对支气管哮喘模型小鼠肺组织及肺T细胞中4种Notch基因表达的特征进行研究,探讨Notch信号在支气管哮喘发病中的作用。方法:制作哮喘小鼠模型,制备肺组织石蜡切片进行病理学检查;从肺组织中分离T细胞,利用RT-PCR半定量技术,测定小鼠肺组织及肺T细胞中4种NotchmRNA的表达量,并与对照组比较。结果:两组小鼠肺组织中4种Notch基因均有表达。哮喘模型组Notch1、Notch2表达较对照组增加(P0.05);Notch4表达组间比较无差异。Notch1、Notch2在肺T细胞中的表达与肺组织中的一致(P<0.05);Notch3、Notch4在T细胞中的表达组间比较无差异。结论:Notch1、2信号在支气管哮喘的发病机制中可能发挥一定作用。     

辛伐他汀对哮喘小鼠血清IL-25及肺功能影响的研究

目的探讨辛伐他汀对支气管哮喘模型小鼠肺功能及血清中白细胞介素-25(IL-25)浓度的影响,为辛伐他汀治疗哮喘提供实验依据。方法选取40只雌性Balb/c小鼠,随机分为对照组、哮喘组、地塞米松组和辛伐他汀组,每组10只,采用卵蛋白(OVA)诱导小鼠哮喘模型。肺功能仪器检测小鼠肺功能指标变化;HE染色观察小鼠肺组织病理变化;细胞计数血中嗜酸粒细胞;酶联免疫吸附法(ELISA)测定血清IL-25浓度。结果哮喘组小鼠肺功能用力最大流速(PEF)、第0.4秒用力呼气容积占用力肺活量比值(FEV0.4/FVC)指标均高于对照组(P<0.05),辛伐他汀组和地塞米松组上述指标则低于哮喘组(P<0.05);哮喘组嗜酸粒细胞总数及IL-25均明显高于对照组(P<0.05),辛伐他汀组和地塞米松组上述指标则低于哮喘组(P<0.05)。结论辛伐他汀能抑制嗜酸粒细胞及IL-25等炎性因子生成,改善哮喘肺功能,缓解哮喘临床症状,对治疗哮喘具有一定的作用。     

Adenovirus expressing Fas ligand gene decreases airway hyper-responsiveness and eosinophilia in a murine model of asthma

Allergic asthma is characterized by airway hyper-responsiveness (AHR) and cellular infiltration of the airway with predominantly eosinophils and Th2 cells. The normal resolution of inflammation in the lung occurs through the regulated removal of unneeded cells by Fas-Fas ligand-mediated apoptosis. Fas ligand (FasL) is a member of the tumor necrosis factor family, and when bound to Fas, it induces apoptosis of the cells. To examine the effect of the FasL gene on airway inflammation and immune effector cells in allergic asthma, recombinant adenovirus expressing murine FasL (Ad-FasL) was delivered intratracheally into ovalbumin (OVA)-immunized mice. We found that a single administration of Ad-FasL in OVA-immunized mice significantly alleviated AHR and eosinophilia by inducing the apoptosis of eosinophils and/or reducing eosinophil attractant factors, such as IL-5 and eotaxin levels. The number of infiltrated lymphocytes and Th2 cytokines, including IL-5 and IL-13, decreased in OVA-immunized mice by administration of Ad-FasL. KC and TNF-alpha production also decreased in Ad-FasL-treated OVA-immunized mice. These findings indicated that the administration of Ad-FasL to OVA-sensitized mice significantly suppressed pulmonary allergic responses. Although more studies are needed, these results suggested that Ad-FasL might be applied as an alternative therapy for allergic asthma.     

Interleukin 4, but not interleukin 5 or eosinophils, is required in a murine model of acute airway hyperreactivity [published erratum appears in J Exp Med 1997 May 5;185(9):1715]

Reversible airway hyperreactivity underlies the pathophysiology of asthma, yet the precise mediators of the response remain unclear. Human studies have correlated aberrant activation of T helper (Th) 2-like effector systems in the airways with disease. A murine model of airway hyperreactivity in response to acetylcholine was established using mice immunized with ovalbumin and challenged with aerosolized antigen. No airway hyperractivity occurred in severe combined immunodeficient mice. Identically immunized BALB/c mice developed an influx of cells, with a predominance of eosinophils and CD4+ T cells, into the lungs and bronchoalveolar lavage fluid at the time that substantial changes in airway pressure and resistance were quantitated. Challenged animals developed marked increases in Th2 cytokine production, eosinophil influx, and serum immunoglobulin E levels. Neutralization of interleukin (IL) 4 using monoclonal antibodies administered during the period of systemic immunization abrogated airway hyperractivity but had little effect on the influx of eosinophils. Administration of anti-IL-4 only during the period of the aerosol challenge did not affect the subsequent response to acetylcholine. Finally, administration of anti- IL-5 antibodies at levels that suppressed eosinophils to < 1% of recruited cells had no effect on the subsequent airway responses. BALB/c mice had significantly greater airway responses than C57BL/6 mice, consistent with enhanced IL-4 responses to antigen in BALB/c mice. Taken together, these data implicate IL-4 generated during the period of lymphocyte priming with antigen in establishing the cascade of responses required to generate airway hyperractivity to inhaled antigen. No role for IL-5 or eosinophils could be demonstrated.     

The importance of leukotrienes in airway inflammation in a mouse model of asthma

Inhalation of antigen in immunized mice induces an infiltration of eosinophils into the airways and increased bronchial hyperreactivity as are observed in human asthma. We employed a model of late-phase allergic pulmonary inflammation in mice to address the role of leukotrienes (LT) in mediating airway eosinophilia and hyperreactivity to methacholine. Allergen intranasal challenge in OVA-sensitized mice induced LTB4 and LTC4 release into the airspace, widespread mucus occlusion of the airways, leukocytic infiltration of the airway tissue and broncho-alveolar lavage fluid that was predominantly eosinophils, and bronchial hyperreactivity to methacholine. Specific inhibitors of 5- lipoxygenase and 5-lipoxygenase-activating protein (FLAP) blocked airway mucus release and infiltration by eosinophils indicating a key role for leukotrienes in these features of allergic pulmonary inflammation. The role of leukotrienes or eosinophils in mediating airway hyperresponsiveness to aeroallergen could not be established, however, in this murine model.     

角质细胞生长因子对小鼠放射性肠损伤的治疗作用

目的本文研究角质细胞生长因子（KGF）对急性放射病小鼠肠损伤的治疗作用。方法将C57BL／6小鼠随机分为空白对照组、照射对照组、KGF低（1mg／kg）、中（2mg／kg）、高（4mg／kg）剂量组5组,空白对照组给予假照射,其他4组给予全身一次性137CS-γ1射线7．2Gy照射,通过观察小鼠大体情况、检测小鼠肠组织蛋白浓度和NO含量及肠组织病理分析,探讨KGF对小鼠肠损伤的保护作用。结果KGF给药组较照射对照组,体重恢复较快;KGF低、中、高剂量组较照射对照组肠组织蛋白浓度明显升高（P〈0．05）,KGF中、高剂量组较照射对照组NO浓度显著降低（P〈0．05）;肠组织病理情况较好。结论KGF对小鼠放射性肠损伤有明显的治疗作用。     

The butyrylcholinesterase knockout mouse as a model for human butyrylcholinesterase deficiency

Butyrylcholinesterase (BChE) is an important enzyme for metabolism of ester drugs. Many humans have partial or complete BChE deficiency due to genetic variation. Our goal was to create a mouse model of BChE deficiency to allow testing of drug toxicity. For this purpose, we created the BChE knockout mouse by gene-targeted deletion of a portion of the BCHE gene (accession number M99492). The BChE(-/-) mouse had no BChE activity in plasma, but it had low residual butyrylthiocholine hydrolase activity in all other tissues attributed to carboxylesterase ES-10. The BChE(-/-) mouse had a normal phenotype except when challenged with drugs. Nicotinic receptor function as indicated by response to nicotine seemed to be normal in BChE(-/-) mice, but muscarinic receptor function as measured by response to oxotremorine and pilocarpine was altered. Heart rate, blood pressure, and respiration, measured in a Vevo imager, were similar in BChE(+/+) and BChE(-/-) mice. Like BChE(-/-) humans, the BChE(-/-) mouse responded to succinylcholine with prolonged respiratory arrest. Bambuterol was not toxic to BChE(-/-) mice, suggesting it is safe in BChE(-/-) humans. Challenge with 150 mg/kg pilocarpine i.p., a muscarinic agonist, or with 50 mg/kg butyrylcholine i.p., induced tonicclonic convulsions and death in BChE(-/-) mice. This suggests that butyrylcholine, like pilocarpine, binds to muscarinic receptors. In conclusion, the BChE(-/-) mouse is a suitable model for human BChE deficiency.     

Hypervolemia induces and potentiates lung damage after recruitment maneuver in a model of sepsis-induced acute lung injury

Introduction

Recruitment maneuvers (RMs) seem to be more effective in extrapulmonary acute lung injury (ALI), caused mainly by sepsis, than in pulmonary ALI. Nevertheless, the maintenance of adequate volemic status is particularly challenging in sepsis. Since the interaction between volemic status and RMs is not well established, we investigated the effects of RMs on lung and distal organs in the presence of hypovolemia, normovolemia, and hypervolemia in a model of extrapulmonary lung injury induced by sepsis.

Methods

ALI was induced by cecal ligation and puncture surgery in 66 Wistar rats. After 48 h, animals were anesthetized, mechanically ventilated and randomly assigned to 3 volemic status (n = 22/group): 1) hypovolemia induced by blood drainage at mean arterial pressure (MAP)≈70 mmHg; 2) normovolemia (MAP≈100 mmHg), and 3) hypervolemia with colloid administration to achieve a MAP≈130 mmHg. In each group, animals were further randomized to be recruited (CPAP = 40 cm H₂O for 40 s) or not (NR) (n = 11/group), followed by 1 h of protective mechanical ventilation. Echocardiography, arterial blood gases, static lung elastance (Est,L), histology (light and electron microscopy), lung wet-to-dry (W/D) ratio, interleukin (IL)-6, IL-1β, caspase-3, type III procollagen (PCIII), intercellular adhesion molecule-1 (ICAM-1), and vascular cell adhesion molecule-1 (VCAM-1) mRNA expressions in lung tissue, as well as lung and distal organ epithelial cell apoptosis were analyzed.

Results

We observed that: 1) hypervolemia increased lung W/D ratio with impairment of oxygenation and Est,L, and was associated with alveolar and endothelial cell damage and increased IL-6, VCAM-1, and ICAM-1 mRNA expressions; and 2) RM reduced alveolar collapse independent of volemic status. In hypervolemic animals, RM improved oxygenation above the levels observed with the use of positive-end expiratory pressure (PEEP), but increased lung injury and led to higher inflammatory and fibrogenetic responses.

Conclusions

Volemic status should be taken into account during RMs, since in this sepsis-induced ALI model hypervolemia promoted and potentiated lung injury compared to hypo- and normovolemia.     

Interleukin (IL) 4 and IL-13 act on human lung fibroblasts. Implication in asthma.

Airway hyperresponsiveness leading to subepithelial fibrosis is mediated by inflammatory cells activated by T helper (Th) 2-derived cytokines such as IL-4 and IL-5. By analyzing the phenotype and response of human lung fibroblasts derived from either fetal (ICIG7) or adult (CCL202) tissue as well as from a Th2-type stromal reaction (FPA) to IL-4 and IL-13, we provide evidence that human lung fibroblasts may behave as inflammatory cells upon activation by IL-4 and IL-13. We show that the three types of fibroblasts constitute different populations that display a distinct pattern in cell surface molecule expression and proinflammatory cytokine and chemokine release. All fibroblasts express functional but different IL-4/IL-13 receptors. Thus, while IL-4 receptor (R) alpha and IL-13Ralpha1 chains are present in all the cells, CCL202 and FPA fibroblasts coexpress the IL-13Ralpha2 and the IL-2Rgamma chain, respectively, suggesting the existence of a heterotrimeric receptor (IL-4Ralpha/IL-13Ralpha/IL-2Rgamma) able to bind IL-4 and IL-13. Stimulation with IL-4 or IL-13 triggers in the fibroblasts a differential signal transduction and upregulation in the expression of beta1 integrin and vascular cell adhesion molecule 1 and in the production of IL-6 and monocyte chemoattractant protein 1, two inflammatory cytokines important in the pathogenesis of allergic inflammation. Our results suggest that when activated by IL-4 and IL-13, different subsets of lung fibroblasts may act as effector cells not only in the pathogenesis of asthma but also in lung remodeling processes. They may also differentially contribute to trigger and maintain the recruitment, homing, and activation of inflammatory cells.     

Effect of dose of hypertonic saline on its potential to prevent lung tissue damage in a mouse model of hemorrhagic shock

Recent studies have shown that hypertonic saline (HS) resuscitation can reduce hemorrhage-induced lung damage by preventing neutrophil activation. In this study, we examined whether this protective effect can be improved by increasing the HS dose used for resuscitation. The protective effect of two HS doses was tested in a mouse model of hemorrhagic shock. BALB/c mice were bled to a mean arterial blood pressure of 35 +/- 5 mmHg for 1 h. Then the animals were resuscitated with lactated Ringer's (LR) or with HS (7.5% NaCl) at doses of 4 mL/kg or 6 mL/kg body weight, sacrificed after 24 h, and lung tissue samples were collected. Evidence of lung injury was evaluated morphologically by scoring histology specimens in a blinded fashion. In a separate set of mice, plasma Na+ and osmolarity were determined 15 min after resuscitation. Resuscitation of hemorrhaged mice with 4 and 6 mL/kg HS increased plasma Na+ concentrations by 5 and 11 mM, respectively. LR treatment reduced plasma Na+ concentrations by 6 mM and resulted in a lung injury score of 6.1 +/- 0.8, accompanied by focal thickening of alveolar membranes, congestion, pulmonary edema, and interstitial and intra-alveolar neutrophil infiltration. HS at 4 mL/kg decreased focal thickening, congestion, pulmonary edema, and neutrophil infiltration, and the injury score to 3.8 +/- 0.9, which was not significantly different from controls (3.6 +/- 0.8), and lung damage was lowest in animals that received 6 mL/kg HS (2.5 +/- 0.2, P < 0.005 vs. LR). Lung damage scores inversely correlated with plasma Na+ concentrations (r > 0.9999). Our data suggest that the protective effect of HS may be a function of the plasma Na+ concentration and that HS at 6 mL/kg is at least equally effective in reducing hemorrhage-induced lung damage compared to the more commonly used HS dose of 4 mL/kg.     

Long-term persistence of gene expression from adeno-associated virus serotype 5 in the mouse airways

Recombinant adeno-associated virus vectors based on serotype 2 (rAAV2) have been used to deliver transgenes to the airways in a variety of pre-clinical and clinical studies. Gene transfer in these studies has been severely restricted by the basolateral localization of rAAV2 receptors. Here, we studied vectors constructed from the AAV5 genome and capsid, which utilize N-linked sialic acid-containing receptors found on the apical surface of airway epithelial cells. We investigated gene transfer efficacy and duration of transgene expression following delivery of rAAV5/5 vectors to the mouse respiratory tract. Robust, dose-dependent transgene expression was observed in the epithelium lining the nose for at least 32 weeks, and for at least 52 weeks in the lung. Importantly, in the lung, transgene expression mediated by rAAV5/5 was 40-fold greater than by rAAV2/2 vectors. A distinct cellular preference for rAAV5/5-mediated transduction was observed, with transgene expression being predominantly restricted to sustentacular cells of the olfactory epithelium in the nose and alveolar type II cells in the lung. Administration of rAAV5/5 vectors to both the nose and lungs led to the rapid development of rAAV5/5-neutralizing antibodies, suggesting that repeated administration may be severely hampered by host immune responses.