P-selectin suppresses hepatic inflammation and fibrosis in mice by regulating interferon gamma and the IL-13 decoy receptor

Key role of macrophages in the progression of hepatic fibrosis

Liver fibrosis is a pathological change characterized by excessive deposition of extracellular matrix caused by chronic liver injury, and the mechanisms underlying its development are associated with endothelial cell injury, inflammatory immune cell activation, and HSC activation. Furthermore, hepatic macrophages exhibit remarkable heterogeneity and hold central functions in the evolution of liver fibrosis, with different subgroups exerting dual effects of promotion and regression. Currently, targeted macrophage therapy for reversing hepatic fibrosis has been extensively studied and has shown promising prospects. In this review, we will discuss the dual role of macrophages in liver fibrosis and provide new insights into reversing liver fibrosis based on macrophages.

An overview of qualitative and quantitative platelet abnormalities in schistosomiasis

Schistosomiasis is a neglected tropical disease referring to the infection with blood parasitic trematodes of the genus Schistosoma. It impacts millions of people worldwide, primarily in low-to-middle-income countries. Patients infected with schistosomiasis often exhibit a distinct hematological profile, including anemia, eosinophilia, thrombocytopenia, and coagulopathy. Platelets, essential components of the hemostatic system, play a crucial role in the pathogenesis of schistosomiasis. Schistosomes secrete serine proteases and express ectoenzymes, such as calpain protease, alkaline phosphatase (SmAP), phosphodiesterase (SmNPP5), ATP diphosphohydrolase (SmATPDase1), serine protease Sk1, SmSP2, and Sm22.6, which can interfere with platelet normal functioning. This report provides comprehensive, up-to-date information on platelet abnormalities observed in patients with schistosomiasis, highlighting their importance in the disease progression and complications. It delves into the interactions between platelets and schistosomes, including the impact of platelet dysfunction on hemostasis and immune responses, immune-mediated platelet destruction, and the potential mechanisms by which schistosome tegumental ectoenzymes affect platelets. Furthermore, the report clarifies the relationship between platelet abnormalities and clinical manifestations such as thrombocytopenia, coagulation disorders, and the emergence of portal hypertension and gastrointestinal bleeding. Understanding the complex interplay between platelets and schistosomes is crucial for improving patient management and outcomes in schistosomiasis, particularly for those with platelet alterations. This knowledge contributes to improved diagnostic methods, innovative treatment strategies, and global efforts to control and eliminate schistosomiasis.

T cells and liver fibrosis

Liver fibrosis develops from the excessive deposition of extracellular matrix in the liver caused by chronic liver inflammation or various chronic injuries, and it eventually develops into liver cirrhosis. The process of liver fibrosis is closely related to the immune response, and increasing evidence reveals the role of T lymphocytes, including Th1, Th2, Th17, regulatory T cells, and mucosa‐associated invariant T cells, in liver fibrosis. These immune cells play antifibrotic or profibrotic roles during fibrosis, and the reversal of fibrosis by targeting immune cells has attracted widespread attention. Activation of hepatic stellate cells, which form the core of fibrosis, is regulated by various immune mediators, including various immune cells and their associated cytokines. Therefore, the mechanism of action elicited by each cell type must be further elucidated to provide a basis for the design of new therapeutic targets. The purpose of this review is to summarize the roles and mechanisms of T lymphocytes and their subsets in liver fibrosis and highlight the biomarkers and potential therapeutic targets associated with these cells.

Lipid-Protein and Protein-Protein Interactions in the Pulmonary Surfactant System and Their Role in Lung Homeostasis

Pulmonary surfactant is a lipid/protein complex synthesized by the alveolar epithelium and secreted into the airspaces, where it coats and protects the large respiratory air–liquid interface. Surfactant, assembled as a complex network of membranous structures, integrates elements in charge of reducing surface tension to a minimum along the breathing cycle, thus maintaining a large surface open to gas exchange and also protecting the lung and the body from the entrance of a myriad of potentially pathogenic entities. Different molecules in the surfactant establish a multivalent crosstalk with the epithelium, the immune system and the lung microbiota, constituting a crucial platform to sustain homeostasis, under health and disease. This review summarizes some of the most important molecules and interactions within lung surfactant and how multiple lipid–protein and protein–protein interactions contribute to the proper maintenance of an operative respiratory surface.

Polymorphisms in Interleukin 13 Signaling and Interacting Genes Predict Advanced Fibrosis and Hepatocellular Carcinoma Development in Non-Alcoholic Steatohepatitis

Background: non-alcoholic steatohepatitis (NASH) recently headlined hepatocellular carcinoma (HCC) worldwide. This study aims to unveil the role of some unaddressed critical players that might aid in understanding, predicting, and targeting NASH and NASH-HCC. Methods: Serum interleukin 13 (IL-13) levels and single nucleotide polymorphisms (SNPs) within interleukin (IL)-13 rs20541, IL-13 receptors (IL-13R1) rs2248841, (IL-13R2) rs5946040, signal transducer activator of transcription 6 (STAT6) rs167769, yes-associated protein (YAP1) rs11225163, programmed death-ligand 1 (PD-L1) rs2282055, and programmed death-ligand 2 (PD-L2) rs7854413 genes were analyzed by qRT-PCR. Multiple stepwise regression analysis was performed on a cohort of 134 Egyptian male patients diagnosed with NASH and NASH-HCC. RESULTS: higher serum alpha-fetoprotein (AFP) and higher serum IL-13 levels were directly associated with HCC development in NASH (odds ratio (OR) 19.6 and 1.9 p < 0.01). Reversibly, the presence of the C/C genotype in STAT6 rs167769 and the C allele carrier YAP1 rs11225163 were inversely associated with HCC in NASH patients (OR 0.015 and 0.047 p < 0.01). A predictive model was formulated with 97.5% specificity, 90.9% sensitivity, and 94.8% accuracy. Moreover, higher serum IL-13 levels and the presence of PD-L2 rs7854413 C allele carriers were associated with advanced fibrosis progression in NASH patients (OR 1.432 and 3.797 p < 0.01). Serum levels of IL-13 and C/C genotype in STAT6 rs167769 significantly increased the predictive capacity of serum AFP to predict HCC in F1–F2 and in F3–F4 fibrosis grades NASH patients. Conclusion: association between serum IL-13 and PD-L2 rs7854413 polymorphism successfully predict advanced fibrosis in NASH. However, HCC development in NASH is associated with higher serum AFP, IL-13 levels, and STAT6 rs167769, YAP1 rs11225163 polymorphisms.

Exploring the Link Between Platelet Numbers and Vascular Homeostasis Across Early and Late Stages of Fibrosis in Hepatitis C

BACKGROUND

Thrombocytopenia is a hallmark of advanced liver disease. Platelets, growth factors (GFs), and vascular integrity are closely linked factors in disease pathogenesis, and their relationship, particularly in early disease stages, is not entirely understood. The aim was to compare circulating platelets, growth factors, and vascular injury markers (VIMs) in hepatitis C-infected (HCV) patients with early fibrosis and cirrhosis.

METHODS

Retrospective evaluation of serum GFs and VIMs by ELISA were evaluated from twenty-six HCV patients. Analytes from an earlier time-point were correlated with MELD at a later time-point.

RESULTS

Platelets and GFs decreased, and VIMs increased with fibrosis. Platelets correlated positively with PDGF-AA, PDGF-BB, TGFB1, EGF, and P-selectin, and negatively with ICAM-3 and VCAM-1. P-selectin showed no correlations with VIMs but positively correlated with PDGF-AA, PDGF-BB, TGFB1, and EGF. Soluble VCAM-1 and ICAM-3 were linked to increasing fibrosis, liver enzymes, and synthetic dysfunction. Higher VCAM-1 and ICAM-3 and lower P-selectin at an earlier time-point were linked to higher MELD score at a later time-point.

CONCLUSION

In chronic HCV, progressive decline in platelets and growth factors with fibrosis and their associations suggest that platelets are an important source of circulating GFs and influence GF decline with fibrosis. Enhanced markers of vascular injury in patients with early fibrosis suggest an earlier onset of endothelial dysfunction preceding cirrhosis. Associations of VIMs with platelets suggest a critical link between platelets and vascular homeostasis. Circulating markers of vascular injury may not only have prognostic importance but emphasize the role of vascular dysfunction in liver disease pathogenesis (NCT00001971).

The Many Roles of Cell Adhesion Molecules in Hepatic Fibrosis

Fibrogenesis is a progressive scarring event resulting from disrupted regular wound healing due to repeated tissue injury and can end in organ failure, like in liver cirrhosis. The protagonists in this process, either liver-resident cells or patrolling leukocytes attracted to the site of tissue damage, interact with each other by soluble factors but also by direct cell–cell contact mediated by cell adhesion molecules. Since cell adhesion molecules also support binding to the extracellular matrix, they represent excellent biosensors, which allow cells to modulate their behavior based on changes in the surrounding microenvironment. In this review, we focus on selectins, cadherins, integrins and members of the immunoglobulin superfamily of adhesion molecules as well as some non-classical cell adhesion molecules in the context of hepatic fibrosis. We describe their liver-specific contributions to leukocyte recruitment, cell differentiation and survival, matrix remodeling or angiogenesis and touch on their suitability as targets in antifibrotic therapies.

Involvement of Hookworm Co-Infection in the Pathogenesis and Progression of Podoconiosis: Possible Immunological Mechanism

Podoconiosis is an endemic, non-infectious, geochemical and non-filarial inflammatory cause of tropical elephantiasis. The immunology of podoconiosis is not yet expressly understood. In spite of this, co-infection and co-morbidity with the infectious, soil-transmitted hookworm disease that causes iron deficiency anemia has been found to be predominant among affected individuals living in co-endemic settings, thus creating a more complex immunological interplay that still has not been investigated. Although deworming and iron-rich nutrient supplementation have been suggested in podoconiosis patients living under resource-poor conditions, and it is thought that hookworm infection may help to suppress inflammatory responses, the undisputed link that exists between a non-infectious and an infectious disease may create a scenario whereby during a co-infection, treatment of one exacerbates the other disease condition or is dampened by the debilitation caused by the other. In this paper, we elaborate on the immunopathogenesis of podoconiosis and examine the possible immunological dynamics of hookworm co-infection in the immunopathology of podoconiosis, with a view toward improved management of the disease that will facilitate its feasible elimination.

Identification of novel host biomarkers in plasma as candidates for the immunodiagnosis of tuberculosis disease and monitoring of tuberculosis treatment response

There is an urgent need for new tools for the rapid diagnosis of tuberculosis disease. We evaluated the potentials of 74 host markers as biomarkers for the immunological diagnosis of tuberculosis and monitoring of treatment response. Fifty-five individuals that presented with signs and symptoms requiring investigation for tuberculosis disease were prospectively recruited prior to clinical diagnosis, at a health centre in Cape Town, South Africa. Patients were later classified as having tuberculosis disease or other respiratory diseases (ORD) using a combination of clinical, radiological and laboratory findings. Out of 74 host markers that were evaluated in plasma samples from study participants using a multiplex platform, 18 showed potential as tuberculosis diagnostic candidates with the most promising being NCAM, CRP, SAP, IP-10, ferritin, TPA, I-309, and MIG, which diagnosed tuberculosis disease individually, with area under the ROC curve ≥0.80. Six-marker biosignatures containing NCAM diagnosed tuberculosis disease with a sensitivity of 100% (95%CI, 86.3-100%) and specificity of 89.3% (95%CI, 67.6-97.3%) irrespective of HIV status, and 100% accuracy in the absence of HIV infection. Furthermore, the concentrations of 11 of these proteins changed with treatment, thereby indicating that they may be useful in monitoring of the response to tuberculosis treatment. Our findings have potential to be translated into a point-of-care screening test for tuberculosis, after future validation studies.

Derivation of Cinnamon Blocks Leukocyte Attachment by Interacting with Sialosides

Molecules derived from cinnamon have demonstrated diverse pharmacological activities against infectious pathogens, diabetes and inflammatory diseases. This study aims to evaluate the effect of the cinnamon-derived molecule IND02 on the adhesion of leukocytes to host cells. The anti-inflammatory ability of IND02, a pentameric procyanidin type A polyphenol polymer isolated from cinnamon alcohol extract, was examined. Pretreatment with IND02 significantly reduced the attachment of THP-1 cells or neutrophils to TNF-α-activated HUVECs or E-selectin/ICAM-1, respectively. IND02 also reduced the binding of E-, L- and P-selectins with sialosides. Furthermore, IND02 could agglutinate human red blood cells (RBC), and the agglutination could be disrupted by sialylated glycoprotein. Our findings demonstrate that IND02, a cinnamon-derived compound, can interact with sialosides and block the binding of selectins and leukocytes with sialic acids.

P selectins and immunological profiles in HCV and Schistosoma mansoni induced chronic liver disease

Background

Hepatitis C virus (HCV) and Schistosoma mansoni are major causes of chronic liver disease (CLD) in which immune alteration is common. Recent studies suggested that certain platelets and lymphocytes activation markers may have an impact on progression of CLD. This study aimed to evaluate the potential of platelets and lymphocytes activation molecules expression on the pathogenesis of CLD in distinct or concomitant chronic HCV and schistosomiasis mansoni infections.

Methods

The study populations were divided into group-I: patients with chronic schistosomiasis mansoni, group-II: HCV patients without cirrhosis, group-III: patients with combined liver diseases without cirrhosis, group-IV: patients with chronic HCV and liver cirrhosis and group-V: Age and sex matched healthy individuals as normal controls. All groups were subjected to full clinical evaluation, ELISA anti-HCV antibodies screening, parasitological examination for diagnosing S. mansoni and flow cytometry for lymphocyte (CD3, CD4, CD8, CD19, CD22, & CD56) and platelets activation (CD41, CD42 & CD62P (P- selectins)) markers.

Results

The platelet count was significantly decreased in HCV and/or S. mansoni patients. The total T-lymphocytes and T-helper cells were significantly reduced, while T-cytotoxics were increased. The patients possessed a significantly higher platelets activation marker; CD62P (P-selectins) and higher mean fluorescent intensity (MFI) positivity. There were considerable correlations between platelets count and both of CD62P and MFI.

Conclusion

Our Findings suggest an increased expression of certain platelets and lymphocytes activation markers in chronic HCV and S. mansoni induced CLD that may have a role in disease progression.

P selectin and T cell profiles provide verification to understand the pathogenesis of liver cirrhosis in HCV and Schistosoma mansoni infections

Hepatitis C virus (HCV) and Schistosoma mansoni are two major causes of chronic liver disease (CLD). Both immune alteration and thrombocytopenia are common complications in the majority of cirrhotic patients. The current study aimed to monitor the effect of T cell profile and platelets activation on the pathogenesis of liver cirrhosis in patients suffered from single or concomitant schistosomiasis and HCV infections. The subjects were divided into 4 groups: Group I, patients infected with schistosomiasis; Group II, patients infected with HCV; Group III, patients with combined liver diseases and Group IV: healthy individuals. All groups were subjected to full clinical evaluation as well as laboratory examination including ELISA anti-HCV antibodies screening, parasitological examination, and complete blood picture as well as flow cytometry for CD41, CD42, CD62P (P selectin), CD63, CD4 and CD8. The platelets count was significantly decreased in HCV and/or schistosoma infected patients compared to controls. The percentage of the total T-lymphocytes and T-helper was significantly reduced in all infected groups, while the percentage of T-cytotoxic was increased. The patients possessed a significantly higher percentage of the platelets activation markers than control group. There were considerable correlations between the platelets counts and P selectin and MFI. Thrombocytopenia was a common finding in patients with CLD. Patients with CLD showed increased platelets activation which may contribute to the occurrence of thrombocytopenia and play a role in the pathogenesis of CLD. Infected patient showed reduction in the cell-mediated-immunity as evidenced by low T -helper cells.

Transcriptional profiling of the bladder in urogenital schistosomiasis reveals pathways of inflammatory fibrosis and urothelial compromise

Urogenital schistosomiasis, chronic infection by Schistosoma haematobium, affects 112 million people worldwide. S. haematobium worm oviposition in the bladder wall leads to granulomatous inflammation, fibrosis, and egg expulsion into the urine. Despite the global impact of urogenital schistosomiasis, basic understanding of the associated pathologic mechanisms has been incomplete due to the lack of suitable animal models. We leveraged our recently developed mouse model of urogenital schistosomiasis to perform the first-ever profiling of the early molecular events that occur in the bladder in response to the introduction of S. haematobium eggs. Microarray analysis of bladders revealed rapid, differential transcription of large numbers of genes, peaking three weeks post-egg administration. Many differentially transcribed genes were related to the canonical Type 2 anti-schistosomal immune response, as reflected by the development of egg-based bladder granulomata. Numerous collagen and metalloproteinase genes were differentially transcribed over time, revealing complex remodeling and fibrosis of the bladder that was confirmed by Masson's Trichrome staining. Multiple genes implicated in carcinogenesis pathways, including vascular endothelial growth factor-, oncogene-, and mammary tumor-related genes, were differentially transcribed in egg-injected bladders. Surprisingly, junctional adhesion molecule, claudin and uroplakin genes, key components for maintaining the urothelial barrier, were globally suppressed after bladder exposure to eggs. This occurred in the setting of urothelial hyperplasia and egg shedding in urine. Thus, S. haematobium egg expulsion is associated with intricate modulation of the urothelial barrier on the cellular and molecular level. Taken together, our findings have important implications for understanding host-parasite interactions and carcinogenesis in urogenital schistosomiasis, and may provide clues for novel therapeutic strategies.

IL-13 Signaling in Liver Fibrogenesis

Liver fibrosis is the final common pathway of chronic liver diseases irrespective of etiology. However, etiology deeply impacts progression and characteristics of liver fibrogenesis. IL-13 is the dominant pro-fibrotic cytokine in Schistosomiasis associated liver fibrogenesis. In vitro, IL-13 directly induces expression of fibrosis-associated genes, e.g., collagens or connective tissue growth factor, in hepatic stellate cells. Recently, potential effects of IL-13 in non-Schistosomiasis associated liver fibrosis have been uncovered. This review summarizes the potential roles of IL-13 in chronic liver disease of different etiologies, and the downstream events mediating IL-13 signaling in liver fibrogenesis.

Selectins and Associated Adhesion Proteins in Inflammatory disorders

Inflammation is defined as the normal response of living tissue to injury or infection. It is important to emphasize two components of this definition. First, that inflammation is a normal response and, as such, is expected to occur when tissue is damaged. Infact, if injured tissue does not exhibit signs of inflammation this would be considered abnormal and wounds and infections would never heal without inflammation. Secondly, inflammation occurs in living tissue, hence there is need for an adequate blood supply to the tissues in order to exhibit an inflammatory response. The inflammatory response may be triggered by mechanical injury, chemical toxins, and invasion by microorganisms, and hypersensitivity reactions. Three major events occur during the inflammatory response: the blood supply to the affected area is increased substantially, capillary permeability is increased, and leucocytes migrate from the capillary vessels into the surrounding interstitial spaces to the site of inflammation or injury. The inflammatory response represents a complex biological and biochemical process involving cells of the immune system and a plethora of biological mediators. Cell-to-cell communication molecules such as cytokines play an extremely important role in mediating the process of inflammation. Inflammation and platelet activation are critical phenomena in the setting of acute coronary syndromes. An extensive exposition of this complex phenomenon is beyond the scope of this article (Rankin 2004).

Irgm1 protects hematopoietic stem cells by negative regulation of IFN signaling

The IFN-inducible immunity-related p47 GTPase Irgm1 has been linked to Crohn disease as well as susceptibility to tuberculosis. Previously we demonstrated that HSC quiescence and function are aberrant in mice lacking Irgm1. To investigate the molecular basis for these defects, we conducted microarray expression profiling of Irgm1-deficient HSCs. Cell-cycle and IFN-response genes are up-regulated in Irgm1(-/-) HSCs, consistent with dysregulated IFN signaling. To test the hypothesis that Irgm1 normally down-regulates IFN signaling in HSCs, we generated Irgm1(-/-)Ifngr1(-/-) and Irgm1(-/-)Stat1(-/-) double-knockout animals. Strikingly, hyperproliferation, self-renewal, and autophagy defects in Irgm1(-/-) HSCs were normalized in double-knockout animals. These defects were also abolished in Irgm1(-/-)Irgm3(-/-) double-knockout animals, indicating that Irgm1 may regulate Irgm3 activity. Furthermore, the number of HSCs was reduced in aged Irgm1(-/-) animals, suggesting that negative feedback inhibition of IFN signaling by Irgm1 is necessary to prevent hyperproliferation and depletion of the stem cell compartment. Collectively, our results indicate that Irgm1 is a powerful negative regulator of IFN-dependent stimulation in HSCs, with an essential role in preserving HSC number and function. The deleterious effects of excessive IFN signaling may explain how hematologic abnormalities arise in patients with inflammatory conditions.

Colitis and intestinal inflammation in IL10-/- mice results from IL-13Rα2-mediated attenuation of IL-13 activity

BACKGROUND & AIMS

The cytokine interleukin (IL)-10 is required to maintain immune homeostasis in the gastrointestinal tract. IL-10 null mice spontaneously develop colitis or are more susceptible to induction of colitis by infections, drugs, and autoimmune reactions. IL-13 regulates inflammatory conditions; its activity might be compromised by the IL-13 decoy receptor (IL-13Rα2).

METHODS

We examined the roles of IL-13 and IL-13Rα2 in intestinal inflammation in mice. To study the function of IL-13Rα2, il10(-/-) mice were crossed with il13rα2(-/-) to generate il10(-/-)il13rα2(-/-) double knockout (dKO) mice. Colitis was induced with the gastrointestinal toxin piroxicam or Trichuris muris infection.

RESULTS

Induction of colitis by interferon (IFN)-γ or IL-17 in IL-10 null mice requires IL-13Rα2. Following exposure of il10(-/-) mice to piroxicam or infection with T muris, production of IL-13Rα2 increased, resulting in decreased IL-13 bioactivity and increased inflammation in response to IFN-γ or IL-17A. In contrast to il10(-/-) mice, dKO mice were resistant to piroxicam-induced colitis; they also developed less severe colitis during chronic infection with T muris infection. In both models, resistance to IFN-γ and IL-17-mediated intestinal inflammation was associated with increased IL-13 activity. Susceptibility to colitis was restored when the dKO mice were injected with monoclonal antibodies against IL-13, confirming its protective role.

CONCLUSIONS

Colitis and intestinal inflammation in IL10(-/-) mice results from IL-13Rα2-mediated attenuation of IL-13 activity. In the absence of IL-13Rα2, IL-13 suppresses proinflammatory Th1 and Th17 responses. Reagents that block the IL-13 decoy receptor IL-13Rα2 might be developed for inflammatory bowel disease associated with increased levels of IFN-γ and IL-17.

Paeoniflorin ameliorates schistosomiasis liver fibrosis through regulating IL-13 and its signalling molecules in mice

Treatment of liver fibrosis associated with Schistosoma japonicum ova-induced granulomas remains a challenging proposition. Paeoniflorin (PAE, C23H28O11) has anti-inflammatory, anti-allergic, and immunoregulatory effects and it is commonly used in Chinese Herbal prescriptions to treat hepatic disorders. The present study was carried out to investigate the effects of PAE on hepatic fibrosis of mice infected with S. japonicum and to explore its possible mechanism. Upon pathological examination of PAE-treated mice, the size of egg granuloma, fibrosis scores, the concentration of IL-13 and hydroxyproline in liver were significantly reduced compared with the model mice. In the primary culture of hepatic stellate cells (HSCs), PAE inhibited IL-13-induced collagen synthesis. These results suggested that PAE might alleviate the hepatic granulomas and fibrosis caused by S. japonicum and the inhibitory effect of PAE on hepatic fibrosis might be associated with its ability to decrease the level of IL-13 and to interfere with the IL-13 signalling molecule in HSCs.

Novel role of IL-13 in fibrosis induced by nonalcoholic steatohepatitis and its amelioration by IL-13R-directed cytotoxin in a rat model

Nonalcoholic steatohepatitis (NASH), the most common cause of chronic liver fibrosis, progresses to cirrhosis in up to 20% of patients. We report that hepatic stellate cells (HSC) in sinusoidal lesions of liver of patients with NASH express high levels of high-affinity IL-13R (IL-13Ralpha2), which is colocalized with smooth muscle actin, whereas fatty liver and normal liver specimens do not express IL-13Ralpha2. HSCs engineered to overexpress IL-13Ralpha2 respond to IL-13 and induce TGFB1 promoter activity and TGF-beta1 production. We also developed NASH in rats by feeding a choline-deficient l-amino acid diet. These rats developed liver fibrosis as assessed by H&E staining, Masson's trichrome and Sirius red staining, and hydroxyproline assays. Treatment of these rats with IL-13R-directed cytotoxin caused a substantial decline in fibrosis and liver enzymes without organ toxicity. These studies demonstrate that functional IL-13Ralpha2 are overexpressed in activated HSCs involved in NASH and that IL-13 cytotoxin ameliorates pathological features of NASH in rat liver, indicating a novel role of this cytotoxin in potential therapy.

Cytokines mediating the induction of chronic colitis and colitis-associated fibrosis

To investigate the immunopathogenesis of inflammation-associated fibrosis we analyzed the chronic colitis and late-developing fibrosis occurring in BALB/c mice administered weekly doses of intrarectal trinitrobenzene sulfonic acid (TNBS). We showed first in this model that an initial T helper type 1 response involving interleukin (IL)-12p70 and interferon-gamma subsides after 3 weeks to be supplanted by an IL-23/IL-25 response beginning after 4-5 weeks. This evolution is followed by gradually increasing production of IL-17 and cytokines ordinarily seen in a T helper type 2 response, particularly IL-13, which reaches a plateau at 8-9 weeks. We then show that IL-13 production results in the induction of an IL-13 receptor formerly thought to function only as a decoy receptor, IL-13Ralpha(2), and this receptor is critical to the production of tumor growth factor (TGF)-beta(1) and the onset of fibrosis. Thus, if IL-13 signaling through this receptor is blocked by administration of soluble IL-13Ralpha(2)-Fc, or by administration of IL-13Ralpha(2)-specific siRNA, TGF-beta(1) is not produced and fibrosis does not occur. These studies show that in chronic TNBS colitis, fibrosis is dependent on the development of an IL-13 response that acts through a novel cell-surface-expressed IL-13 receptor to induce TGF-beta(1).

Restoration of tumor immunosurveillance via targeting of interleukin-13 receptor-alpha 2

In previous studies, we described a "counter-immunosurveillance" mechanism initiated by tumor-activated, interleukin-13 (IL-13)-producing natural killer T cells that signal Gr-1(+) cells to produce transforming growth factor-beta(1) (TGF-beta(1)), a cytokine that suppresses the activity of tumor-inhibiting cytolytic CD8(+) T cells. Here, we show that in two tumor models (the CT-26 metastatic colon cancer and the 15-12RM fibrosarcoma regressor models), this counter-surveillance mechanism requires the expression of a novel IL-13 receptor, IL-13R alpha(2), on Gr-1(intermediate) cells, because down-regulation of IL-13R alpha(2) expression or the activator protein-1 signal generated by the receptor via in vivo administration of specific small interfering RNA or decoy oligonucleotides leads to loss of TGF-beta(1) production. Furthermore, acting on prior studies showing that IL-13R alpha(2) expression is induced (in part) by tumor necrosis factor-alpha (TNF-alpha), we show that receptor expression and TGF-beta(1) production is inhibited by administration of a TNF-alpha-neutralizing substance, TNF-alpha R-Fc (etanercept). Taking advantage of this latter fact, we then show in the CT-26 model that counter-immunosurveillance can be inhibited, anti-CT-26-specific CD8(+) cytolytic activity can be restored, and CT-26 metastatic tumor nodules can be greatly decreased by administration of TNF-alpha R-Fc. Corroborative data were obtained using the 15-12RM fibrosarcoma model. These studies point to the prevention of metastatic cancer with an available agent with already known clinically acceptable adverse effects and toxicity.

Induction of IL-13 triggers TGF-beta1-dependent tissue fibrosis in chronic 2,4,6-trinitrobenzene sulfonic acid colitis

To investigate the immunopathogenesis of inflammation-associated fibrosis, we analyzed the chronic colitis and late-developing fibrosis occurring in BALB/c mice administered weekly doses of intrarectal 2,4,6-trinitrobenzene sulfonic acid. We showed first in this model that an initial Th1 response involving IL-12p70 and IFN-gamma subsides after 3 wk to be supplanted by an IL-23/IL-25 response beginning after 4-5 wk. This evolution is followed by gradually increasing production of IL-17 and cytokines ordinarily seen in a Th2 response, particularly IL-13, which reaches a plateau at 8-9 wk. In vitro stimulation studies suggest that this IL-13 production is dependent on IL-23 and IL-25, but not on IL-12p70. We then show that IL-13 production results in the induction of an IL-13R formerly thought to function only as a decoy receptor, IL-13Ralpha(2), and this receptor is critical to the production of TGF-beta(1) and the onset of fibrosis. Thus, if IL-13 signaling through this receptor is blocked by administration of soluble IL-13Ralpha(2)-Fc, or by administration of IL-13Ralpha(2)-specific small interfering RNA, TGF-beta(1) is not produced and fibrosis does not occur. These studies show that in chronic 2,4,6-trinitrobenzene sulfonic acid colitis, fibrosis is dependent on the development of an IL-13 response that acts through a novel cell surface-expressed IL-13R to induce TGF-beta(1). A similar mechanism may obtain in certain forms of human inflammatory bowel disease.

Participação das plaquetas no processo de fibrose dos pacientes com esquistossomose mansônica

O objetivo deste estudo foi avaliar a ativação plaquetária através da P-selectina e o conteúdo de PDGF-AB e TGFbeta1, nos pacientes com esquistossomose que desenvolveram fibrose (F3), naqueles que não tiveram esta manifestação (F0) e nos controles (C). Os resultados mostraram que a percentagem de P-selectina nas plaquetas sem estímulo de agonistas foi de 10,6% nos F3; 11,1% nos FO, e 6,3% nos C e após a adição de ADP/adrenalina, foi de 44%; 25,3% e 42%, respectivamente. A dosagem do PDGF-AB e TGFbeta1 por plaquetas foi de 11,016ng/dL (F3); 3,172 ng/dL (F0) e 5,01ng/dL (C) e, (0,012ng/dL (F3); 5,27ng/dL (F0) e 4,66ng/dL (C), respectivamente. Em relação à P-selectina, concluímos que as plaquetas dos pacientes com esquistossomoses, apesar de estarem pré ativadas, mantiveram-se responsivas aos agonistas. O TFGbeta1 não apresentou diferença entre os três grupos, enquanto o PDGF-AB foi significantemente maior no grupo F3, sugerindo a participação deste no desenvolvimento da fibrose.

IL-13 is pivotal in the fibro-obliterative process of bronchiolitis obliterans syndrome

Acute allograft rejection is considered to be a predominately type 1 immune mediated response to the donor alloantigen. However, the type 2 immune mediated response has been implicated in multiple fibroproliferative diseases. Based on the fibro-obliterative lesion found during bronchiolitis obliterans syndrome (BOS), we hypothesized that the type 2 immune mediated response is involved in chronic lung allograft rejection. Specifically, whereas acute rejection is, in part, a type 1 immune response, chronic rejection is, in part, a type 2 immune response. We found the type 2 cytokine, IL-13, to be elevated and biologically active in human bronchoalveolar lavage fluid during BOS. Translational studies using a murine model of BOS demonstrated increased expression of IL-13 and its receptors that paralleled fibro-obliteration. In addition, in vivo neutralization of IL-13 reduced airway allograft matrix deposition and murine BOS, by a mechanism that was independent of IL-4. Furthermore, using IL-13Ralpha2(-/-) mice, we found increased fibro-obliteration. Moreover, anti-IL-13 therapy in combination with cyclosporin A had profound effects on reducing murine BOS. This supports the notion that IL-13 biological axis plays an important role during the pathogenesis of BOS independent of the IL-4 biological axis.

A role for endothelial selectins in allergic and nonallergic inflammatory disease

BACKGROUND

Several studies indicate that selectin-mediated leukocyte migration may depend on the types of initiating inflammatory stimuli or on the vascular beds involved in the inflammatory response. Thus, targeting selectin interactions to treat inflammation may have variable effects depending on the site and origin of the inflammatory response.

OBJECTIVE

To address whether selectin-mediated leukocyte recruitment is stimulus or tissue dependent.

METHODS

We examined pulmonary and cutaneous allergic inflammatory responses and silica-induced nonallergic lung inflammation and fibrosis in wild-type and P- and E-selectin-deficient (P/E-/-) double knockout mice. Allergen-sensitized wild-type and P/E-/- double knockout mice were challenged either intradermally or via the airways to induce allergic responses in the skin or lung, respectively. Other animals were subjected to intranasal silica administration to induce a nonallergic lung inflammatory/fibrotic response.

RESULTS

The P/E-/- mice exhibited significantly reduced allergic inflammation in the skin and lung. Allergic late-phase ear swelling and allergic lung airway hyperresponsiveness were also significantly attenuated in the P/E-/- mice compared with identically treated wild-type animals. In contrast, pulmonary inflammation and fibrosis induced by intranasal administration of silica particles resulted in a more severe phenotype in the P/E-/- mice.

CONCLUSIONS

Selectin interactions drive allergic inflammation in the lung and skin. Silica-induced pulmonary inflammation and fibrosis, however, was more pronounced in the absence of selectin interactions, suggesting that selectin-mediated leukocyte migration may depend on the types of initiating inflammatory stimuli.

Exploiting worm and allergy models to understand Th2 cytokine biology

PURPOSE OF REVIEW

Helminthic parasites and many allergens trigger highly polarized Th2-type immune responses. In most helminth infections, the Th2 response often leads to parasite expulsion or sequestration. During murine Schistosoma mansoni infection, however, the parasites persist and the chronic Th2 response induces severe pathological changes in the gut and liver. Thus, the study of schistosome infections in mice has become a popular model to study the pathogenesis of Th2 cytokine-mediated disease. This review will discuss recent findings from the schistosomiasis model that may be relevant to the understanding of allergic inflammation, asthma and Th2 cytokine biology in general.

RECENT FINDINGS

Evidence is accumulating that the Th2 pathway is not a 'default pathway' but one that is actively instructed by mechanisms that are only beginning to be understood. Other areas of intensive investigation include studies on alternatively activated macrophages, the role of dendritic cells in Th2 response development, the inhibitory function of IL-10, regulatory T-cells and decoy receptors on chronic Th2-mediated inflammation, and the role of chitinases in mediating Th2 disease. Finally, the development of novel eosinophil-deficient mice has also accelerated our understanding of the contribution of this important cell type to Th2 immunity.

SUMMARY

Many findings from the schistosomiasis model have been subsequently demonstrated in models of allergic disease, illustrating the utility of this model to dissect basic mechanisms of Th2-mediated inflammation. Further study of helminth-induced Th2 responses may expedite the discovery of new therapeutics for a wide range of Th2-associated diseases.

Serum levels of soluble P-selectin are increased and associated with disease activity in patients with Behçet's syndrome

Behçet's syndrome (BS) is a relapsing, chronic, inflammatory disease characterized by endothelial dysfunction, atherothromboembogenesis, and leukocytoclastic vasculitis with complex immunologic molecular interactions. Generalized derangements of the lymphocyte and neutrophil populations, activated monocytes, and increased PMNLs motility with upregulated cell surface molecules such as ICAM-1, VCAM-1, and E-selectin, which are found on the endothelial cells, leukocytes, and platelets, have all been demonstrated during the course of BS. Our aim is to investigate the association of serum concentrations of soluble P-selectin in patients with BS, and to evaluate whether disease activity has an effect on their blood levels. This multicenter study included 31 patients with BS (15 men and 16 women) and 20 age- and sex-matched healthy control volunteers (11 men and nine women). Neutrophil count, erythrocyte sedimentation rate, and acute-phase reactants as well as soluble P-selectin levels were determined. The mean age and sex distributions were similar (P > .05) between BS patients (35 years) and control volunteers (36 years). Serum levels of soluble P-selectin in patients with BS (399 +/- 72 ng/mL) were significantly (P < .001) higher when compared with control subjects (164 +/- 40 ng/mL). In addition, active BS patients (453 +/- 37 ng/mL) had significantly (P < .001) elevated levels of soluble P-selectin than those in inactive period (341 +/- 52 ng/mL). This study clearly demonstrated that serum soluble P-selectin levels are increased in BS patients when compared with control subjects, suggesting a modulator role for soluble P-selectin during the course of platelet activation and therefore, atherothrombogenesis formation in BS, especially in active disease.

IL-13 signaling through the IL-13alpha2 receptor is involved in induction of TGF-beta1 production and fibrosis

Interleukin (IL)-13 is a major inducer of fibrosis in many chronic infectious and autoimmune diseases. In studies of the mechanisms underlying such induction, we found that IL-13 induces transforming growth factor (TGF)-beta(1) in macrophages through a two-stage process involving, first, the induction of a receptor formerly considered to function only as a decoy receptor, IL-13Ralpha(2). Such induction requires IL-13 (or IL-4) and tumor necrosis factor (TNF)-alpha. Second, it involves IL-13 signaling through IL-13Ralpha(2) to activate an AP-1 variant containing c-jun and Fra-2, which then activates the TGFB1 promoter. In vivo, we found that prevention of IL-13Ralpha(2) expression reduced production of TGF-beta(1) in oxazolone-induced colitis and that prevention of IL-13Ralpha(2) expression, Il13ra2 gene silencing or blockade of IL-13Ralpha(2) signaling led to marked downregulation of TGF-beta(1) production and collagen deposition in bleomycin-induced lung fibrosis. These data suggest that IL-13Ralpha(2) signaling during prolonged inflammation is an important therapeutic target for the prevention of TGF-beta(1)-mediated fibrosis.

Liver fibrosis caused by choledocholith to regress after biliary drainage

AIM: To study the correlation between liver fibrosis severity and biliary drainage in patients with choledocholith.

METHODS: A follow-up study on seven patients with liver fibrosis due to choledocholith was made. The data, including biochemical tests (aspartate aminotransferase, alanine aminotransferase) and liver histological features before and after biliary drainage, were collected and studied. The fibrosis severity was scored on a scale from 0 to 3, with 0 denoting none, 1 portal and periportal fibrosis, 2 the presence of numerous fiber septa, and 3 cirrhosis. The average liver fibrosis severity scores of the first and second biopsy were compared with statistical method.

RESULTS: The first, second liver fibrosis severity scores of these seven patients were 2,1; 2,1; 1,0; 1,1; 2,1; 2,1; 1,0 respectively. The results showed that the average liver fibrosis severity score of the second liver biopsy decreased significantly compared with the first liver biopsy (n = 7, t = 4.25, P<0.05).

CONCLUSION: Liver fibrosis due to choledocholith may regress after biliary drainage.

Opposing roles for IL-13 and IL-13 receptor alpha 2 in health and disease

Interleukin (IL)-13 is a key inducer of several type-2 cytokine-dependent pathologies. It regulates inflammation, mucus production, tissue remodeling, and fibrosis. Consequently, it has become an important therapeutic target for a number of debilitating illnesses, including asthma, idiopathic pulmonary fibrosis, ulcerative colitis, as well as several other diseases in which IL-13 is believed to be overproduced. In the murine model of schistosomiasis, IL-13 has emerged as a central mediator of chronic infection-induced liver pathology. Although IL-4, IL-5, IL-10, and IL-13 each regulate distinct aspects of the granulomatous inflammatory response, IL-13 was identified as the primary mediator of liver fibrosis. Thus, elucidating the mechanisms that regulate the production and function of IL-13 has become an intensive area of research. IL-13 signaling is mediated by the type-2 IL-4 receptor, which consists of the IL-4R alpha and IL-13R alpha 1 chains. However, another IL-13-binding chain, IL-13R alpha 2, appears to strongly inhibit the activity of IL-13. Animals deficient in IL-13R alpha 2 fail to downmodulate granuloma formation in the chronic phase of infection. They also develop severe IL-13-dependent fibrosis and portal hypertension and quickly succumb to the infection. Here, we summarize findings from the schistosomiasis model, which illustrate opposing activities for IL-13 and IL-13R alpha 2 in health and disease.

Helminth parasites--masters of regulation

Immune regulation by parasites is a global concept that includes suppression, diversion, and conversion of the host immune response to the benefit of the pathogen. While many microparasites escape immune attack by antigenic variation or sequestration in specialized niches, helminths appear to thrive in exposed extracellular locations, such as the lymphatics, bloodstream, or gastrointestinal tract. We review here the multiple layers of immunoregulation that have now been discovered in helminth infection and discuss both the cellular and the molecular interactions involved. Key events among the host cell population are dominance of the T-helper 2 cell (Th2) phenotype and the selective loss of effector activity, against a background of regulatory T cells, alternatively activated macrophages, and Th2-inducing dendritic cells. Increasingly, there is evidence of important effects on other innate cell types, particularly mast cells and eosinophils. The sum effect of these changes to host reactivity is to create an anti-inflammatory environment, which is most favorable to parasite survival. We hypothesize therefore that parasites have evolved specific molecular strategies to induce this conducive landscape, and we review the foremost candidate immunomodulators released by helminths, including cytokine homologs, protease inhibitors, and an intriguing set of novel products implicated in immune suppression.