Commensal-dependent expression of IL-25 regulates the IL-23-IL-17 axis in the intestine

Alterations in the composition of intestinal commensal bacteria are associated with enhanced susceptibility to multiple inflammatory diseases, including those conditions associated with interleukin (IL)-17-producing CD4(+) T helper (Th17) cells. However, the relationship between commensal bacteria and the expression of proinflammatory cytokines remains unclear. Using germ-free mice, we show that the frequency of Th17 cells in the large intestine is significantly elevated in the absence of commensal bacteria. Commensal-dependent expression of the IL-17 family member IL-25 (IL-17E) by intestinal epithelial cells limits the expansion of Th17 cells in the intestine by inhibiting expression of macrophage-derived IL-23. We propose that acquisition of, or alterations in, commensal bacteria influences intestinal immune homeostasis via direct regulation of the IL-25-IL-23-IL-17 axis.     

Characterization of the interleukin 2 receptors (IL-2R) expressed on human natural killer cells activated in vivo by IL-2: association of the p64 IL-2R gamma chain with the IL-2R beta chain in functional intermediate-affinity IL-2R

Interleukin 2 (IL-2) receptors expressed on the surface of activated T cells and natural killer (NK) cells exhibit a variety of affinity states depending on their subunit composition. Low-affinity binding is associated with a 55-kDa alpha chain, intermediate-affinity binding with a 70-75-kD beta chain, and high-affinity binding with a bimolecular complex of the alpha and beta subunits. In a previous study of the IL-2 receptors expressed on NK cells obtained from cancer patients after in vivo IL-2 therapy, we documented a discrepancy between the level of beta chain and the level of intermediate-affinity IL-2 binding sites expressed on the cell surface. Based on this result, we postulated that formation of intermediate-affinity receptor sites required a component in addition to the beta chain, and that this component was present at limiting levels in the patient NK cells. In the present study we have examined the structure of the intermediate-affinity receptor complex using monoclonal antibodies that recognize the beta chain, but that do not interfere with its ability to bind IL-2. Evidence is presented establishing the physical association of a novel protein of 64 kD with the beta chain in intermediate-affinity IL-2 binding sites. This molecule, termed IL-2R gamma chain, coprecipitated with beta chains prepared from cells that had been incubated with IL-2, but was undetectable in immunoprecipitates prepared in the absence of IL-2. Examination of gamma chain expression in post-IL-2 therapy NK cells, where only low levels of intermediate-affinity IL-2 binding were detectable, revealed that the gamma chain was associated with, on average, only 10-12% of the beta chains expressed on such cells. This contrasted with approximately equal levels of beta and gamma chain expression on YT cells, a cell line that has both high levels of cell surface beta chain expression and high levels of IL-2 binding. Thus, the ratio of gamma chain to beta chain present in the immunoprecipitates roughly correlated with the proportion of beta chain involved in intermediate-affinity receptor sites. This result suggests that the 64-kD gamma chain is the component responsible for regulating the affinity of IL-2 association with the beta subunit. By further defining the structural components necessary for IL-2 receptor formation, these studies provide additional insight into mechanisms whereby lymphocytes might regulate their responsiveness to IL-2.     

Opposing activities of two novel members of the IL-1 ligand family regulate skin inflammation

The interleukin (IL)-1 family members IL-1α, -1β, and -18 are potent inflammatory cytokines whose activities are dependent on heterodimeric receptors of the IL-1R superfamily, and which are regulated by soluble antagonists. Recently, several new IL-1 family members have been identified. To determine the role of one of these family members in the skin, transgenic mice expressing IL1F6 in basal keratinocytes were generated. IL1F6 transgenic mice exhibit skin abnormalities that are dependent on IL-1Rrp2 and IL-1RAcP, which are two members of the IL-1R family. The skin phenotype is characterized by acanthosis, hyperkeratosis, the presence of a mixed inflammatory cell infiltrate, and increased cytokine and chemokine expression. Strikingly, the combination of the IL-1F6 transgene with an IL1F5 deficiency results in exacerbation of the skin phenotype, demonstrating that IL-1F5 has antagonistic activity in vivo. Skin from IL1F6 transgenic, IL1F5^−/− pups contains intracorneal and intraepithelial pustules, nucleated corneocytes, and dilated superficial dermal blood vessels. Additionally, expression of IL1RL2, -1F5, and -1F6 is increased in human psoriatic skin. In summary, dysregulated expression of novel agonistic and antagonistic IL-1 family member ligands can promote cutaneous inflammation, revealing potential novel targets for the treatment of inflammatory skin disorders.     

Adenosine mediates IL-13-induced inflammation and remodeling in the lung and interacts in an IL-13-adenosine amplification pathway

IL-13 is an important mediator of inflammation and remodeling. We hypothesized that adenosine accumulation, alterations in adenosine receptors, and adenosine-IL-13 autoinduction are critical events in IL-13-induced pathologies. To test this, we characterized the effects of IL-13 overexpression on the levels of adenosine, adenosine deaminase (ADA) activity, and adenosine receptors in the murine lung. We also determined whether adenosine induced IL-13 in lungs from ADA-null mice. IL-13 induced an inflammatory and remodeling response that caused respiratory failure and death. During this response, IL-13 caused a progressive increase in adenosine accumulation, inhibited ADA activity and mRNA accumulation, and augmented the expression of the A1, A2B, and A3 but not the A2A adenosine receptors. ADA enzyme therapy diminished the IL-13-induced increase in adenosine, inhibited IL-13-induced inflammation, chemokine elaboration, fibrosis, and alveolar destruction, and prolonged the survival of IL-13-transgenic animals. In addition, IL-13 was strongly induced by adenosine in ADA-null mice. These findings demonstrate that adenosine and adenosine signaling contribute to and influence the severity of IL-13-induced tissue responses. They also demonstrate that IL-13 and adenosine stimulate one another in an amplification pathway that may contribute to the nature, severity, progression, and/or chronicity of IL-13 and/or Th2-mediated disorders.     

造血干细胞移植患者血清IL-2及其受体检测的临床意义

目的评估细胞因子白细胞介素-2(interleukin-2,IL-2)及其受体(IL-2 receptor,IL-2R)在造血干细胞移植期间的变化和临床价值。方法用ELISA法检测了34例造血干细胞移植患者在移植前、预处理后、骨髓抑制期、感染期、造血恢复后2个月以及移植物抗宿主病(graft versus host disease,GVHD)发生时血清IL-2和IL-2R的水平。结果在发生细菌感染的患者中,IL-2和IL-2R分别为233.4±103.6 pg/mL和357.4±159.2 pmol/L,显著高于未发生细菌感染组(169.7±37.3 pg/mL和257.6±48.8 pmol/L,P=0.0490和0.0453)和正常对照组(167.8±38.6 pg/mL和249.7±48.1pmol/L,P=0.0111和0.0062)。同时,两者在巨细胞病毒(Cytomegavirus,CMV)感染的患者中(291.4±51.7pg/mL和326.5±108.6 pmol/L)亦显著高于CMV阴性组(187.2±69.7pg/mL和225.3±46.1 pmol/L,P均=0.0005)和正常对照组(P=0.0002和0.0141)。此外,患者在发生GVHD时IL-2和IL-2R(328.6±141.7)pg/mL和321.8±49.2 pmol/L)较移植前(201.4±83.4 pg/mL和250.8±39.7 pmol/L)均显著增高(P=0.0055和0.0105)。结论细胞因子IL-2及其受体在感染的发生和GVHD的发病中起重要的正向调节作用,定期检测患者血清IL-2和IL-2R水平有助于预测感染和GVHD的发生。     

ERK1/2 mitogen-activated protein kinase selectively mediates IL-13-induced lung inflammation and remodeling in vivo

IL-13 dysregulation plays a critical role in the pathogenesis of a variety of inflammatory and remodeling diseases. In these settings, STAT6 is believed to be the canonical signaling molecule mediating the tissue effects of IL-13. Signaling cascades involving MAPKs have been linked to inflammation and remodeling. We hypothesized that MAPKs play critical roles in effector responses induced by IL-13 in the lung. We found that Tg IL-13 expression in the lung led to potent activation of ERK1/2 but not JNK1/2 or p38. ERK1/2 activation also occurred in mice with null mutations of STAT6. Systemic administration of the MAPK/ERK kinase 1 (MEK1) inhibitor PD98059 or use of Tg mice in which a dominant-negative MEK1 construct was expressed inhibited IL-13-induced inflammation and alveolar remodeling. There were associated decreases in IL-13-induced chemokines (MIP-1alpha/CCL-3, MIP-1beta/CCL-4, MIP-2/CXCL-1, RANTES/CCL-5), MMP-2, -9, -12, and -14, and cathepsin B and increased levels of alpha1-antitrypsin. IL-13-induced tissue and molecular responses were noted that were equally and differentially dependent on ERK1/2 and STAT6 signaling. Thus, ERK1/2 is activated by IL-13 in the lung in a STAT6-independent manner where it contributes to IL-13-induced inflammation and remodeling and is required for optimal IL-13 stimulation of specific chemokines and proteases as well as the inhibition of specific antiproteases. ERK1/2 regulators may be useful in the treatment of IL-13-induced diseases and disorders.     

Vasopressin decreases sepsis-induced pulmonary inflammation through the V2R

The early use of vasopressors in sepsis has been associated with a decrease in immune activation independent of hemodynamic effects, although the mechanism behind this remains unclear. We hypothesize that low dose vasopressin will reduce the pulmonary inflammation associated with sepsis. Our aims were to (1) determine whether vasopressin reduces lipopolysaccharide (LPS)-induced pulmonary inflammation and (2) determine which vasopressin receptor is responsible for pulmonary immune modulation. Mice were treated with intraperitoneal LPS to induce both systemic and pulmonary inflammation. Vasopressin or saline was infused via peritoneal pump and interleukin 6 (IL-6) in lung and serum was measured at 6h. NF-kappaB activation as was determined in the lung through immunoblotting total and phospho-IkappaB. Hemodynamic data was also obtained at the 6h mark. In a separate series of experiments mice received both LPS and vasopressin infusion following pretreatment with vasopressin receptor antagonists to V1R, V2R and OTR. Low dose LPS dramatically raises both serum IL-6 and pulmonary levels of IL-6 and phospho-IkappaB despite no significant changes in mean arterial pressure at 6h. Compared to saline, vasopressin infusion significantly decreases both the pulmonary IL-6 levels and phospho-IkappaB in LPS treated mice without raising arterial pressure. Pretreatment with V2R antagonist results in complete attenuation of vasopressin's immunosuppressive effects, with restoration of pulmonary IL-6 and phospho-IkappaB levels to those seen with LPS alone. CONCLUSIONS: Vasopressin exerts a local anti-inflammatory effect on the lung through the V2R in a model of sepsis.     

The IL-23/IL-17 axis in inflammation

IL-23 induces the differentiation of naive CD4(+) T cells into highly pathogenic helper T cells (Th17/Th(IL-17)) that produce IL-17, IL-17F, IL-6, and TNF-alpha, but not IFN-gamma and IL-4. Two studies in this issue of the JCI demonstrate that blocking IL-23 or its downstream factors IL-17 and IL-6, but not the IL-12/IFN-gamma pathways, can significantly suppress disease development in animal models of inflammatory bowel disease and MS (see the related articles beginning on pages 1310 and 1317). These studies suggest that the IL-23/IL-17 pathway may be a novel therapeutic target for the treatment of chronic inflammatory diseases.     

The IL-6R alpha chain controls lung CD4+CD25+ Treg development and function during allergic airway inflammation in vivo

The cytokine IL-6 acts via a specific receptor complex that consists of the membrane-bound IL-6 receptor (mIL-6R) or the soluble IL-6 receptor (sIL-6R) and glycoprotein 130 (gp130). In this study, we investigated the role of IL-6R components in asthma. We observed increased levels of sIL-6R in the airways of patients with allergic asthma as compared to those in controls. In addition, local blockade of the sIL-6R in a murine model of late-phase asthma after OVA sensitization by gp130-fraction constant led to suppression of Th2 cells in the lung. By contrast, blockade of mIL-6R induced local expansion of Foxp3-positive CD4+CD25+ Tregs with increased immunosuppressive capacities. CD4+CD25+ but not CD4+CD25- lung T cells selectively expressed the IL-6R alpha chain and showed IL-6-dependent STAT-3 phosphorylation. Finally, in an in vivo transfer model of asthma in immunodeficient Rag1 mice, CD4+CD25+ T cells isolated from anti-IL-6R antibody-treated mice exhibited marked immunosuppressive and antiinflammatory functions. IL-6 signaling therefore controls the balance between effector cells and Tregs in the lung by means of different receptor components. Furthermore, inhibition of IL-6 signaling emerges as a novel molecular approach for the treatment of allergic asthma.     

雷公藤多甙对大鼠原位肝移植急性排斥反应中IL-2、IL-2R活性的影响及肝细胞作用

目的探讨雷公藤多甙对大鼠原位肝移植免疫抑制的作用机理。方法将120只肝移植SD大鼠分为4组:对照组(A组),TⅡ组(B组),CsA组(C组),TⅡ CsA组(D组),分别检测移植术后各组1、3、5、7、14d外周血IL-2R的含量和脾脏淋巴细胞的IL-2活性及肝细胞凋亡相关基因Bcl-2、FasL的蛋白表达。结果三组治疗组的IL-2活性和IL-2R含量均明显低于对照组,三组治疗组间的比较是D组低于B、C组,上述均有统计学意义(P<0.05)。三组治疗组的Bcl-2的蛋白表达低于对照组,FasL的表达高于对照组,而三组间的比较:D组低于C组,C组低于B组,上述均有统计学意义(P<0.05)。结论雷公藤多甙通过对IL-2、IL-2R和Bcl-2、FasL的影响来达到免疫抑制作用,如果联合CsA效果会更好。     

Blocking IL-1 in systemic inflammation

A growing number of systemic inflammatory diseases characterized in part by recurrent fevers, leukocytosis, anemia, and elevated acute phase proteins are linked to interleukin (IL)-1 activity since rapid and sustained resolution is observed upon specific blockade of IL-1 receptors. Rapid resolution of systemic and local inflammation is now also reported in systemic onset juvenile idiopathic arthritis (SoJIA). Loss of control of the secretion of IL-1beta might be a common mechanism explaining the aberrant activity of IL-1 in these diseases.     

IL-21R is essential for epicutaneous sensitization and allergic skin inflammation in humans and mice

Atopic dermatitis (AD) is a common allergic inflammatory skin disease caused by a combination of intense pruritus, scratching, and epicutaneous (e.c.) sensitization with allergens. To explore the roles of IL-21 and IL-21 receptor (IL-21R) in AD, we examined skin lesions from patients with AD and used a mouse model of allergic skin inflammation. IL-21 and IL-21R expression was upregulated in acute skin lesions of AD patients and in mouse skin subjected to tape stripping, a surrogate for scratching. The importance of this finding was highlighted by the fact that both Il21r^–/– mice and WT mice treated with soluble IL-21R–IgG2aFc fusion protein failed to develop skin inflammation after e.c. sensitization of tape-stripped skin. Adoptively transferred OVA-specific WT CD4⁺ T cells accumulated poorly in draining LNs (DLNs) of e.c. sensitized Il21r^–/– mice. This was likely caused by both DC-intrinsic and nonintrinsic effects, because trafficking of skin DCs to DLNs was defective in Il21r^–/– mice and, to a lesser extent, in WT mice reconstituted with Il21r^–/– BM. More insight into this defect was provided by the observation that skin DCs from tape-stripped WT mice, but not Il21r^–/– mice, upregulated CCR7 and migrated toward CCR7 ligands. Treatment of epidermal and dermal cells with IL-21 activated MMP2, which has been implicated in trafficking of skin DCs. These results suggest an important role for IL-21R in the mobilization of skin DCs to DLNs and the subsequent allergic response to e.c. introduced antigen.     

Drug interactions in Brazilian type 2 diabetes patients

The aim of this paper is to identify the prevalence of the most frequent drug interactions in patients using oral antidiabéticos and their association with capillary glucose and medication adherence. In total, 579 type 2 diabetes mellitus patients from 12 health institutions in Fortaleza, Brazil were interviewed in 2009. A form was applied, including questions on medication use, comorbidities, lifestyle, body mass index and random capillary glucose. Results revealed that 26.7% used five or more different drugs simultaneously and daily. Statistically significant drug interactions occurred between antidiabéticos and diuretics, angiotensin‐converting enzyme inhibitors, anti‐lipidaemics and corticoids. No significant association was found between polypharmacy, medication adherence and glucose. It is important for nurses, in consensus with other health professionals, to consider the possibility of other drugs that mean less risk for diabetes patients’ glucose control or of increased antidiabetics doses.     

乳腺癌患者外周血中白介素-2受体、白介素-6和肿瘤坏死因子-α的检测及临床意义

目的:探讨外周血白介素-2受体(sIL-2R)、白介素-6(IL-6)和肿瘤坏死因子-α(TNF-α)在乳腺癌患者外周血中表达水平的变化及临床意义。方法:应用酶联免疫吸附法检测62例乳腺癌(乳腺癌组)和45例乳腺良性病患者(乳腺良性病组)的sIL-2R、IL-6、TNF-α水平,并以50例健康志愿者(对照组)为对照。结果:乳腺癌组外周血浆sIL-2R、IL-6、TNF-α水平明显高于乳腺良性病组和对照组,且乳腺癌组各临床分期间外周血浆的sIL-2R、IL-6、TNF-α水平差异存在显著性,即Ⅲ期高于Ⅱ期,Ⅱ期高于Ⅰ期(均P<0.001)。结论:外周血sIL-2R、IL-6、TNF-α表达水平与乳腺癌的临床分期联系紧密,各分期间差异有显著性。检测其表达水平的变化对观察病情进展及判断预后有一定的参考价值。     

Targeted inactivation of the IL-4 receptor alpha chain I4R motif promotes allergic airway inflammation

The insulin/interleukin-4 (IL-4) receptor (I4R) motif mediates the association of insulin receptor substrate (IRS)-2 with the interleukin-4 (IL-4)Ralpha chain and transduces mitogenic signals in response to IL-4. Its physiological functions were analyzed in mice with a germline point mutation that changed the motif's effector tyrosine residue into phenylalanine (Y500F). The Y500F mutation abrogated IRS-2 phosphorylation and impaired IL-4-induced CD4+ T lymphocyte proliferation but left unperturbed Stat6 activation, up-regulation of IL-4-responsive gene products, and Th cell differentiation under Th2 polarizing conditions. However, in vivo the Y500F mutation was associated with increased allergen-induced IgE production, airway responsiveness, tissue eosinophilia, and mucus production. These results define an important role for the I4R motif in regulating allergic inflammation.     

IL-1R1/MyD88 signaling and the inflammasome are essential in pulmonary inflammation and fibrosis in mice

The molecular mechanisms of acute lung injury resulting in inflammation and fibrosis are not well established. Here we investigate the roles of the IL-1 receptor 1 (IL-1R1) and the common adaptor for Toll/IL-1R signal transduction, MyD88, in this process using a murine model of acute pulmonary injury. Bleomycin insult results in expression of neutrophil and lymphocyte chemotactic factors, chronic inflammation, remodeling, and fibrosis. We demonstrate that these end points were attenuated in the lungs of IL-1R1– and MyD88-deficient mice. Further, in bone marrow chimera experiments, bleomycin-induced inflammation required primarily MyD88 signaling from radioresistant resident cells. Exogenous rIL-1β recapitulated a high degree of bleomycin-induced lung pathology, and specific blockade of IL-1R1 by IL-1 receptor antagonist dramatically reduced bleomycin-induced inflammation. Finally, we found that lung IL-1β production and inflammation in response to bleomycin required ASC, an inflammasome adaptor molecule. In conclusion, bleomycin-induced lung pathology required the inflammasome and IL-1R1/MyD88 signaling, and IL-1 represented a critical effector of pathology and therapeutic target of chronic lung inflammation and fibrosis.     

Neutrophil AKT2 regulates heterotypic cell-cell interactions during vascular inflammation

Interactions between platelets, leukocytes, and activated endothelial cells are important during microvascular occlusion; however, the regulatory mechanisms of these heterotypic cell-cell interactions remain unclear. Here, using intravital microscopy to evaluate mice lacking specific isoforms of the serine/threonine kinase AKT and bone marrow chimeras, we found that hematopoietic cell–associated AKT2 is important for neutrophil adhesion and crawling and neutrophil-platelet interactions on activated endothelial cells during TNF-α–induced venular inflammation. Studies with an AKT2-specific inhibitor and cells isolated from WT and Akt KO mice revealed that platelet- and neutrophil-associated AKT2 regulates heterotypic neutrophil-platelet aggregation under shear conditions. In particular, neutrophil AKT2 was critical for membrane translocation of αMβ2 integrin, β2-talin1 interaction, and intracellular Ca²⁺ mobilization. We found that the basal phosphorylation levels of AKT isoforms were markedly increased in neutrophils and platelets isolated from patients with sickle cell disease (SCD), an inherited hematological disorder associated with vascular inflammation and occlusion. AKT2 inhibition reduced heterotypic aggregation of neutrophils and platelets isolated from SCD patients and diminished neutrophil adhesion and neutrophil-platelet aggregation in SCD mice, thereby improving blood flow rates. Our results provide evidence that neutrophil AKT2 regulates αMβ2 integrin function and suggest that AKT2 is important for neutrophil recruitment and neutrophil-platelet interactions under thromboinflammatory conditions such as SCD.