Interactions of human galectins with Trypanosoma cruzi: binding profile correlate with genetic clustering of lineages

This is a pre-copyedited, author-produced PDF of an article accepted for publication in Glycobiology following peer review. The version of record Pineda, M.A. et al. Interactions of human galectins with Trypanosoma cruzi: binding profile correlate with genetic clustering of lineages. Glycobiology 25.2 (2015): 197-210 is available online at: http://dx.doi.org/10.1093/glycob/cwu103We report here the specific interaction between several members of the human galectin family with the three developmental stages of several genetic lineages of the protozoan parasite Trypanosoma cruzi. We provide data of specific and differential binding of human galectins-1, 3, 4, 7 and 8 to 14 strains of T. cruzi that belong to the six genetic lineages representing the genetic diversity of the parasite. It is shown that galectins preferentially bind forms present in the host, trypomastigotes and amastigotes, compared to the non-infective epimastigote present on the intestinal tract of the vector, reflecting the changes on glycosylation that occur during the metacyclogenesis and amastigogenesis process. Also, it is evidenced that galectin binding to the parasites promotes binding to the host cells and higher infection rates. In addition evidence is provided indicating that the intracellular amastigotes may take over the cytosolic pool of some galectins when released to the extracellular medium. Finaly, by applying unweighted pair group method analysis to the galectin binding profile to either cell-derived trypomastigotes or amastigotes we show that the differential binding profile by the host galectins to the six lineages resembles the clustering based in genetic data. Therefore, the differential binding profile for the six lineages could have implications in the immunopathology of Chagas’ disease, affecting the complex network of immune responses on which galectins mediate, thus providing linkage clues to the notion that different lineages may be related to different clnical forms of the disease.This work was supported by grants from the Fondo de Investigaciones Sanitarias-Ministerio de Sanidad (FIS-PI11/00033) to PB and (FIS-PI11/0095) to MS, and grant ChagasEpiNet (European VII framework Program) to MF. The financial support Network RICET from the FIS, Ministerio de Sanidad and Fundacion Ramon Areces is acknowledge

Oxidative stress targets in pulmonary emphysema: focus on the Nrf2 pathway

IMPORTANCE OF THE FIELD: Oxidative stress has been implicated in the pathogenesis of pulmonary emphysema. Nuclear factor erythroid-2-related factor 2 (Nrf2) a major antioxidant transcription factor could play a protective role in pulmonary emphysema. AREAS COVERED IN THIS REVIEW: Nrf2 is ubiquitously expressed throughout the lung, but is predominantly found in epithelium and alveolar macrophages. Evidence suggests that Nrf2 and several Nrf2 downstream genes have an essential protective role in the lung against oxidative stress from environmental pollutants and toxicants such as cigarette smoke, a major causative factor for the development and progression of pulmonary emphysema. Application of Nrf2-deficient mice identified an extensive range of protective roles for Nrf2 against the pathogenesis of pulmonary emphysema. Therefore, Nrf2 promises to be an attractive therapeutic target for intervention and prevention strategies. WHAT THE READER WILL GAIN: In this review, we discuss recent findings on the association of oxidative stress with pulmonary emphysema. We also address the mechanisms of Nrf2 lung protection against oxidative stress based on emerging evidence from experimental oxidative disease models and human studie. TAKE HOME MESSAGE: The current literature suggests that among oxidative stress targets, Nrf2 is a valuable therapeutic target in pulmonary emphysema

La voie Nrf2 en pathologie respiratoire

Airways are continually exposed to multiple inhaled oxidants and protect themselves with cellular and extracellular antioxidants throughout the epithelial lining fluid and tissues. Oxidative stress, resulting from the increased oxidative burden and decreased level of antioxidant proteins, is involved in cellular and tissue damage related to the pathogenesis of many acute and chronic respiratory diseases. Evidence suggested that nuclear factor erythroid-2-related factor 2 (Nrf2), a transcription factor that controls antioxidant response element (ARE)-regulated antioxidant and cytoprotective genes has an essential protective role in the lungs against oxidative airway diseases. Therefore, Nrf2 promises to be an attractive therapeutic target for intervention and prevention strategies in respiratory diseases. We have reviewed major findings on the mechanisms of lung protection against oxidative stress by Nrf2 and the current literature suggesting that Nrf2 is a valuable therapeutic target

Key role of the 3' untranslated region in the cell cycle regulated expression of the Leishmania infantum histone H2A genes: minor synergistic effect of the 5' untranslated region

<p>Abstract</p> <p>Background</p> <p>Histone synthesis in <it>Leishmania </it>is tightly coupled to DNA replication by a post-transcriptional mechanism operating at the level of translation.</p> <p>Results</p> <p>In this work we have analyzed the implication of the 5' and 3' untranslated regions (UTR) in the cell cycle regulated expression of the histone <it>H2A </it>in <it>Leishmania infantum</it>. For that purpose, <it>L. infantum </it>promastigotes were stably transfected with different plasmid constructs in which the <it>CAT </it>coding region used as a reporter was flanked by the 5' and 3' UTR regions of the different <it>H2A </it>genes. We report that in spite of their sequence differences, histone <it>H2A </it>5' and 3' UTRs conferred a cell cycle dependent pattern of expression on the CAT reporter since <it>de novo </it>synthesis of CAT increased when parasites enter the S phase. Using one established <it>L. infantum </it>cell line we showed that CAT expression is controlled by the same regulatory events that control the endogenous histone gene expression. Thus, although we did not detect changes in the level of <it>CAT </it>mRNAs during cell cycle progression, a drastic change in the polysome profiles of <it>CAT </it>mRNAs was observed during the progression from G1 to S phase. In the S phase <it>CAT </it>mRNAs were on polyribosomal fractions, but in the G1 phase the association of <it>CAT </it>transcripts with ribosomes was impaired. Furthermore, it was determined that the addition of just the <it>H2A </it>3' UTR to the <it>CAT </it>reporter gene is sufficient to achieve a similar pattern of post-transcriptional regulation indicating that this region contains the major regulatory sequences involved in the cell cycle dependent expression of the <it>H2A </it>genes. On the other hand, although CAT transcripts bearing the <it>H2A </it>5' alone were translated both in the G1 and S phase, higher percentages of transcripts were detected on polyribosomes in the S phase correlating with an increase in the <it>de novo </it>synthesis of CAT. Thus, it can be concluded that this region also contributes, although to a minor extent than the 3' UTR, in the enhancement of translation in the S phase relative to the G1 phase.</p> <p>Conclusion</p> <p>Our findings indicate that both, the 5' and the 3' UTRs contain sequence elements that contribute to the cell cycle expression of <it>L. infantum </it>H2A. The 3' UTR region is essential for cell cycle dependent translation of the <it>L. infantum </it>H2A transcripts whereas the 5' UTR has a minor contribution in their S phase dependent translation.</p

Altered Nrf2/Keap1-Bach1 equilibrium in pulmonary emphysema

BACKGROUND: Oxidative stress, resulting from the increased oxidative burden and decreased level of antioxidant proteins, plays a role in the pathophysiology of smoking-related pulmonary emphysema. Expression of several antioxidant proteins, such as heme oxygenase-1 (HO-1), glutathione peroxidase 2 (GPX2) and NAD(P)H:quinone oxidoreductase 1 (NQO1), results from an equilibrium created by positive or negative regulation by the transcription factors Nrf2, Keap1 and Bach1, respectively. However, whether the expression of these transcription factors is altered in emphysema and could account for decreased expression of antioxidant proteins is not known. A study was undertaken to investigate the expression and subcellular localisation of Nrf2, Keap1 and Bach1 as potential regulators of HO-1, GPX2 and NQO1 in alveolar macrophages, a key cell in oxidative stress, in lung surgical specimens from non-smokers without emphysema and smokers with and without emphysema. METHODS AND RESULTS: Western blot, immunohistochemical and laser scanning confocal analysis revealed that the Nrf2 protein level decreased significantly in whole lung tissue and alveolar macrophages (cytosol and nucleus) in patients with emphysema compared with those without emphysema. Conversely, Bach1 and Keap1 levels were increased in patients with emphysema. These modifications were associated with a parallel decrease in the expression of HO-1, GPX2 and NQO1 at the cellular level, which was inversely correlated with airway obstruction and distension indexes, and increased macrophage expression of the lipid peroxidation product 4-hydroxy-2-nonenal. Silencing RNA experiments in vitro in THP-1 cells were performed to confirm the cause-effect relation between the loss of Nrf2 and the decrease in HO-1, NQO1 and GPX2 expression. Nrf2/Keap1-Bach1 equilibrium was altered in alveolar macrophages in pulmonary emphysema, which points to a decreased stress response phenotype. CONCLUSIONS: This finding opens a new view of the pathophysiology of emphysema and could provide the basis for new therapeutic approaches based on preservation and/or restoration of such equilibrium

NRF2 targeting: a promising therapeutic strategy in chronic obstructive pulmonary disease.

Several convergent destructive mechanisms such as oxidative stress, alveolar cell apoptosis, extracellular matrix proteolysis and chronic inflammation contribute to chronic obstructive pulmonary disease (COPD) development. Evidence suggests that oxidative stress contributes to the pathophysiology of COPD, particularly during exacerbations. Nuclear factor erythroid-2-related factor 2 (NRF2), a transcription factor expressed predominantly in epithelium and alveolar macrophages, has an essential protective role in the lungs through the activation of antioxidant response element-regulated antioxidant and cytoprotective genes. Animal models and human studies have identified NRF2 and several NRF2 target genes as a protective system against inflammation and oxidative stress from cigarette smoke, a major causative factor in COPD development. Hence, NRF2 targeting might provide clinical benefit by reducing both oxidative stress and inflammation in COPD

Prolonged cigarette smoke exposure decreases heme oxygenase-1 and alters Nrf2 and Bach1 expression in human macrophages: roles of the MAP kinases ERK(1/2) and JNK

Tobacco may be involved in the decreased macrophage heme oxygenase-1 (HO-1) expression described in smoking-induced severe emphysema, via the nuclear factor erythroid 2-related factor 2 (Nrf2)/Kelch-like ECH-associated protein 1 (Keap1)-BTB and CNC homology 1, basic leucine zipper transcription factor 1 (Bach1) pathway. We assessed in vitro effects of cigarette smoke condensate (CS) in the human monocyte/macrophage cell line (THP-1). CS exposure led to increased HO-1 and nuclear Nrf2 expression (6 h) followed by decreased HO-1 expression concomitantly with nuclear Nrf2/Bach1 ratio decrease (72h). CS-induced mitogen-activated protein kinase (MAPK) phosphorylation. Extracellular-signal-regulated kinase(1/2) (ERK(1/2)) and c-Jun NH2-terminal kinase (JNK) inhibition completely abrogated CS effects on HO-1 expression and nuclear Nrf2/Bach1 translocation. These results suggest that ERK(1/2) and JNK are involved in CS-induced biphasic HO-1 expression by a specific regulation of Nrf2/Keap1-Bach1

Nuclear factor erythroid 2-related factor 2 nuclear translocation induces myofibroblastic dedifferentiation in idiopathic pulmonary fibrosis

AIMS: Oxidants have been implicated in the pathophysiology of idiopathic pulmonary fibrosis (IPF), especially in myofibroblastic differentiation. We aimed at testing the hypothesis that nuclear factor erythroid 2-related factor 2 (Nrf2), the main regulator of endogenous antioxidant enzymes, is involved in fibrogenesis via myofibroblastic differentiation. Fibroblasts were cultured from the lungs of eight controls and eight IPF patients. Oxidants-antioxidants balance, nuclear Nrf2 expression, and fibroblast phenotype (α-smooth muscle actin and collagen I expression, proliferation, migration, and contraction) were studied under basal conditions and after Nrf2 knockdown or activation by Nrf2 or Keap1 siRNA transfection. The effects of sulforaphane (SFN), an Nrf2 activator, on the fibroblast phenotype were tested under basal and pro-fibrosis conditions (transforming growth factor β [TGF-β]). RESULTS: Decreased Nrf2 expression was associated with a myofibroblast phenotype in IPF compared with control fibroblasts. Nrf2 knockdown induced oxidative stress and myofibroblastic differentiation in control fibroblasts. Conversely, Nrf2 activation increased antioxidant defences and myofibroblastic dedifferentation in IPF fibroblasts. SFN treatment decreased oxidants, and induced Nrf2 expression, antioxidants, and myofibroblastic dedifferentiation in IPF fibroblasts. SFN inhibited TGF-β profibrotic deleterious effects in IPF and control fibroblasts and restored antioxidant defences. Nrf2 knockdown abolished SFN antifibrosis effects, suggesting that they were Nrf2 mediated. INNOVATION AND CONCLUSION: Our findings confirm that decreased nuclear Nrf2 plays a role in myofibroblastic differentiation and that SFN induces human pulmonary fibroblast dedifferentiation in vitro via Nrf2 activation. Thus, Nrf2 could be a novel therapeutic target in IPF

Induction of Heme Oxygenase-1, Biliverdin Reductase and H-Ferritin in Lung Macrophage in Smokers with Primary Spontaneous Pneumothorax: Role of HIF-1α

Few data concern the pathophysiology of primary spontaneous pneumothorax (PSP), which is associated with alveolar hypoxia/reoxygenation. This study tested the hypothesis that PSP is associated with oxidative stress in lung macrophages. We analysed expression of the oxidative stress marker 4-HNE; the antioxidant and anti-inflammatory proteins heme oxygenase-1 (HO-1), biliverdin reductase (BVR) and heavy chain of ferritin (H-ferritin); and the transcription factors controlling their expression Nrf2 and HIF-1alpha, in lung samples from smoker and nonsmoker patients with PSP (PSP-S and PSP-NS), cigarette smoke being a risk factor of recurrence of the disease.mRNA was assessed by RT-PCR and proteins by western blot, immunohistochemistry and confocal laser analysis. 4-HNE, HO-1, BVR and H-ferritin were increased in macrophages from PSP-S as compared to PSP-NS and controls (C). HO-1 increase was associated with increased expression of HIF-1alpha mRNA and protein in alveolar macrophages in PSP-S patients, whereas Nrf2 was not modified. To understand the regulation of HO-1, BVR and H-ferritin, THP-1 macrophages were exposed to conditions mimicking conditions in C, PSP-S and PSP-NS patients: cigarette smoke condensate (CS) or air exposure followed or not by hypoxia/reoxygenation. Silencing RNA experiments confirmed that HIF-1alpha nuclear translocation was responsible for HO-1, BVR and H-ferritin induction mediated by CS and hypoxia/reoxygenation.PSP in smokers is associated with lung macrophage oxidative stress. The response to this condition involves HIF-1alpha-mediated induction of HO-1, BVR and H-ferritin