Nuestros investigadores

María Esther Larrea Leoz

Instituto Salud Tropical
Instituto Salud Tropical. Universidad de Navarra
Facultad de Ciencias. Universidad de Navarra
Unidad Docente de Medicina Traslacional
Facultad de Medicina. Universidad de Navarra
Líneas de investigación
Leishmaniasis, Immune response, Virus
Índice H
22, (WoS, 30/06/2020)

Publicaciones científicas más recientes (desde 2010)

Autores: Calvo Bacaicoa, Alba; Moreno Amatria, Esther; Larrea Leoz, María Esther; et al.
ISSN 1999-4923  Vol. 12  Nº 9  2020  págs. E858
Berberine (BER)-an anti-inflammatory quaternary isoquinoline alkaloid extracted from plants-has been reported to have a variety of biologic properties, including antileishmanial activity. This work addresses the preparation of BER-loaded liposomes with the aim to prevent its rapid liver metabolism and improve the drug selective delivery to the infected organs in visceral leishmaniasis (VL). BER liposomes (LP-BER) displayed a mean size of 120 nm, negative Z-potential of -38 mV and loaded 6 nmol/¿mol lipid. In vitro, the loading of BER in liposomes enhanced its selectivity index more than 7-fold by decreasing its cytotoxicity to macrophages. In mice, LP-BER enhanced drug accumulation in the liver and the spleen. Consequently, the liposomal delivery of the drug reduced parasite burden in the liver and spleen by three and one logarithms (99.2 and 93.5%), whereas the free drug only decreased the infection in the liver by 1-log. The organ drug concentrations-far from IC50 values- indicate that BER immunomodulatory activity or drug metabolites also contribute to the efficacy. Although LP-BER decreased 10-fold-an extremely rapid clearance of the free drug in mice-the value remains very high. Moreover, LP-BER reduced plasma triglycerides levels.
Autores: Vacas Oleas, Andrés Fernando; Fernández Rubio, Celia; Larrea Leoz, María Esther; et al.
ISSN 2227-9059  Vol. 8  Nº 11  2020  págs. 452
A novel serine/threonine protein kinase, LmjF.22.0810, was recently described in Leishmania major. After generating an L. major cell line overexpressing LmjF.22.0810 (named LmJ3OE), the ability of this novel protein to modulate the Th2-type immune response was analyzed. Our results suggest that the protein kinase LmjF.22.0810 might be involved in leishmaniasis outcomes. Indeed, our study outlined the LmJ3OE parasites infectivity in vitro and in vivo. Transgenic parasites displayed lower phagocytosis rates in vitro, and their promastigote forms exhibited lower expression levels of virulence factors compared to their counterparts in control parasites. In addition, LmJ3OE parasites developed significantly smaller footpad swelling in susceptible BALB/c mice. Hematoxylin-eosin staining allowed the observation of a lower inflammatory infiltrate in the footpad from LmJ3OE-infected mice compared to animals inoculated with control parasites. Gene expression of Th2-associated cytokines and effectors revealed a dramatically lower induction in interleukin (IL)-4, IL-10, and arginase 1 (ARG1) mRNA levels at the beginning of the swelling; no expression change was found in Th1-associated cytokines except for IL-12. Accordingly, such results were validated by immunohistochemistry studies, illustrating a weaker expression of ARG1 and a similar induction for inducible NO synthase (iNOS) in footpads from LmJ3OE-infected mice compared to control L. major infected animals. Furthermore, the parasite burden was lower in footpads from LmJ3OE-infected mice. Our analysis indicated that such significant smaller footpad swellings might be due to an impairment of the Th2 immune response that subsequently benefits Th1 prevalence. Altogether, these studies depict LmjF.22.0810 as a potential modulator of host immune responses to Leishmania. Finally, this promising target might be involved in the modulation of infection outcome.
Autores: Fernandez-Rubio, C.; Larrea Leoz, María Esther; Peña Guerrero, J.; et al.
ISSN 0066-4804  Vol. 63  Nº 2  2019  págs. e00904-18
Conventional chemotherapy against leishmaniasis includes agents exhibiting considerable toxicity. In addition, reports of drug resistance are not uncommon. Thus, safe and effective therapies are urgently needed. Isoselenocyanate compounds have recently been identified with potential antitumor activity. It is well known that some antitumor agents demonstrate effects against Leishmania In this study, the in vitro leishmanicidal activities of several organo-selenium and organo-sulfur compounds were tested against Leishmania major and Leishmania amazonensis parasites, using promastigotes and intracellular amastigote forms. The cytotoxicity of these agents was measured in murine peritoneal macrophages and their selectivity indexes were calculated. One of the tested compounds, the isoselenocyanate derivative NISC-6, showed selectivity indexes 2- and 10-fold higher than those of the reference drug amphotericin B when evaluated in L. amazonensis and L. major, respectively. The American strain (L. amazonensis) was less sensitive to NISC-6 than L. major, showing a trend similar to that observed previously for amphotericin B. In addition, we also observed that NISC-6 significantly reduced the number of amastigotes per infected macrophage. On the other hand, we showed that NISC-6 decreases expression levels of Leishmania genes involved in the cell cycle, such as topoisomerase-2 (TOP-2), PCNA, and MCM4, therefore contributing to its leishmanicidal activity. The effect of this compound on cell cycle progression was confirmed by flow cytometry. We observed a significant increase of cells in the G1 phase and a dramatic reduction of cells in the S phase compared to untreated cells. Altogether, our data suggest that the isoselenocyanate NISC-6 may be a promising candidate for new drug development against leishmaniasis.
Autores: Vacas Oleas, Andrés Fernando; Fernández Rubio, Celia; Algarabel Olona, Miriam; et al.
ISSN 2218-273X  Vol. 9  Nº 11  2019 
The identification and clarification of the mechanisms of action of drugs used against leishmaniasis may improve their administration regimens and prevent the development of resistant strains. Herein, for the first time, we describe the structure of the putatively essential Ser/Thr kinase LmjF.22.0810 from Leishmania major. Molecular dynamics simulations were performed to assess the stability of the kinase model. The analysis of its sequence and structure revealed two druggable sites on the protein. Furthermore, in silico docking of small molecules showed that aminoglycosides preferentially bind to the phosphorylation site of the protein. Given that transgenic LmjF.22.0810-overexpressing parasites displayed less sensitivity to aminoglycosides such as paromomycin, our predicted models support the idea that the mechanism of drug resistance observed in those transgenic parasites is the tight binding of such compounds to LmjF.22.0810 associated with its overexpression. These results may be helpful to understand the complex machinery of drug response in Leishmania.
Autores: Vacas Oleas, Andrés Fernando; Fernández Rubio, Celia; Larrea Leoz, María Esther; et al.
ISSN 0002-9637  Vol. 101  Nº Supl. 5  2019  págs. 171
Autores: Schwartz Mota, Juana; Moreno Amatria, Esther; Calvo Bacaicoa, Alba; et al.
ISSN 0923-1811  Vol. 92  Nº 1  2018  págs. 78 - 88
Background: Cutaneous leishmaniasis (CL) skin lesions are the result of a deregulated immune response, which is unable to eliminate Leishmania parasites. The control of both, parasites and host immune response, is critical to prevent tissue destruction. The skin ulceration has been correlated with high TNF-alpha level. Objective: Because human anti-TNF-alpha antibodies (Ab) have been successfully assayed in several mice inflammatory diseases, we hypothesized that their anti-inflammatory effect could optimize the healing of CL lesions achieved after topical application of paromomycin (PM), the current chemotherapy against CL. Methods and results: We first compared the in vitro efficacy of PM and Ab alone and the drug given in combination with Ab to assess if the Ab could interfere with PM leishmanicidal activity in L. major-infected bone marrow-derived macrophages. The combination therapy had similar antileishmanial activity to the drug alone and showed no influence on NO production, which allows macrophage-mediated parasite killing. Next, we demonstrated in an in vivo model of Imiquimod (R)-induced inflammation that topical Ab and PM inhibit the infiltration of inflammatory cells in the skin. In the efficacy studies in L. major-infected BALB/c mice, PM combined with Ab led to a sharp infection reduction and showed a stronger anti-inflammatory activity than PM alone. This was confirmed by the down-regulation of TNE-alpha, IL-1 beta, iNOS, IL 17, and CCL3 as well as by a decrease of the neutrophilic infiltrate during infection upon treatment with the Ab. Conclusions: In terms of parasite elimination and inflammation reduction, topical application of Ab in combination with PM was more effective than the drug alone. (C) 2018 Japanese Society for Investigative Dermatology. Published by Elsevier B.V. All rights reserved.
Autores: Rodríguez-García, E. ; Olague Micheltorena, María Cristina; Ríus-Rocabert, S. ; et al.
ISSN 2573-7732  Vol. 2  Nº 11  2018  págs. 363 - 376
The innate immune system provides a primary line of defense against pathogens. Stimulator of IFN genes (STING), encoded by the TMEM173 gene, is a critical protein involved in IFN-ß induction in response to infection by different pathogens. In this study, we describe the expression of three different alternative-spliced human (h) TMEM173 mRNAs producing STING truncated isoforms 1, 2, and 3 in addition to the full-length wild-type (wt) hSTING. All of the truncated isoforms lack exon 7 and share the N-terminal transmembrane region with wt hSTING. Overexpression of the three STING truncated isoforms failed to induce IFN-ß, and they acted as selective pathway inhibitors of wt hSTING even in combination with upstream inducer cyclic-di-GMP-AMP synthase. Truncated isoforms alter the stability of wt hSTING, reducing protein t1/2 to some extent by the induction of proteasome-dependent degradation. Knocking down expression of truncated isoforms increased production of IFN-ß by THP1 monocytes in response to intracellular cytosolic DNA or HSV-1 infection. At early stages of infection, viruses like HSV-1 or vesicular stomatitis virus reduced the ratio of full-length wt hSTING/truncated STING isoforms, suggesting the skewing of alternative splicing of STING toward truncated forms as a tactic to evade antiviral responses. Finally, in silico analysis revealed that the human intron¿exon gene architecture of TMEM173 (splice sites included) is preserved in other mammal species, predominantly primates, stressing the relevance of alternative splicing in regulating STING antiviral biology.
Autores: Peña Guerrero, José; Algarabel Olona, Miriam; Fernández Rubio, Celia; et al.
ISSN 0002-9637  Vol. 99  Nº 4  2018  págs. 176 - 177
Autores: Vacas, A. ; Sugden, C. ; Velasco-Rodríguez, Ó.; et al.
ISSN 2090-0023  Vol. 2017  Nº 2017  2017  págs. 1964531
Leishmania is the causative agent of leishmaniasis, a neglected tropical disease that affects more than 12 million people around the world. Current treatments are toxic and poorly effective due to the acquisition of resistance within Leishmania populations. Thus, the pursuit for new antileishmanial drugs is a priority. The available methods for drug screening based on colorimetric assays using vital dyes are time-consuming. Currently, the use of fluorescent reporter proteins is replacing the use of viability indicator dyes. We have constructed two plasmids expressing the red fluorescent protein mCherry with multiple cloning sites (MCS), adequate for N- and C-terminal fusion protein constructs. Our results also show that the improved pXG-mCherry plasmid can be employed for drug screening in vitro. The use of the red fluorescent protein, mCherry, is an easier tool for numerous assays, not only to test pharmacological compounds, but also to determine the subcellular localization of proteins.
Autores: Moreno Amatria, Esther; Schwartz, J.; Calvo, A.; et al.
ISSN 0378-5173  Vol. 533  Nº 1  2017  págs. 236 - 244
Vaccine delivery using microneedles (MNs) represents a safe, easily disposable and painless alternative to traditional needle immunizations. The MN delivery of DNA vaccines to the dermis may result in a superior immune response and/or an equivalent immune response at a lower vaccine dose (dose-sparing). This could be of special interest for immunization programs against neglected tropical diseases such as leishmaniasis. In this work, we loaded a MN device with 60 mu g of a plasmid DNA cocktail encoding the Leishmania infantum nucleosomal histones H2A, H2B, H3 and H4 and compared its immunogenicity and protective capacity against conventional s.c. or i.d. injection of the plasmid. Mice immunized with MNs showed increased ratios of IFN-gamma/IL-10, IFN-gamma/IL-13, IFN-gamma/IL-4, and IFN-gamma/TGF-beta in the spleens and lymph nodes compared with mice immunized by s.c. and i.d. routes. Furthermore, CCXCL9, CXCL10 and CCL2 levels were also higher. These data suggest that the nucleic acid immunization using MNs produced a better bias towards a Th1 response. However, none of the immunizations strategies were able to control Leishmania major infection in BALB/c mice, as illustrated by an increase in lesion size and parasite burden.
Autores: Zabaleta Azpiroz, Aintzane; Riezu Boj, José Ignacio; Larrea Leoz, María Esther; et al.
ISSN 0146-6615  Vol. 88  Nº 5  2016  págs. 843 - 851
Viral clearance during acute hepatitis C virus (HCV) infection is associated with the induction of potent antiviral T-cell responses. Since dendritic cells (DC) are essential in the activation of primary T-cell responses, gene expression was analyzed in DC from patients during acute HCV infection. By using microarrays, gene expression was compared in resting and activated peripheral blood plasmacytoid (pDC) and myeloid (mDC) DC from acute HCV resolving patients (AR) and from patients who become chronically infected (ANR), as well as in healthy individuals (CTRL) and chronically-infected patients (CHR). For pDC, a high number of upregulated genes was found in AR patients, irrespective of DC stimulation. However, for mDC, most evident differences were detected after DC stimulation, again corresponding to upregulated genes in AR patients. Divergent behavior of ANR was also observed when analyzing DC from CTRL and CHR, with ANR patients clustering again apart from these groups. These differences corresponded to metabolism-associated genes and genes belonging to pathways relevant for DC activation and cytokine responses. Thus, upregulation of relevant genes in DC during acute HCV infection may determine viral clearance, suggesting that dysfunctional DC may be responsible for the lack of efficient T-cell responses which lead to chronic HCV infection.
Autores: Vásquez Durán, Marcos Antonio; Fioravanti, Jessica; Aranda Vega, Fernando; et al.
ISSN 2162-402X  Vol. 5  Nº 8  2016  págs. e1196309
Scavenger receptor class B type I (SR-B1) binds pathogen-associated molecular patterns participating in the regulation of the inflammatory reaction but there is no information regarding potential interactions between SR-B1 and the interferon system. Herein, we report that SR-B1 ligands strongly regulate the transcriptional response to interferon ¿ (IFN¿) and enhance its antiviral and antitumor activity. This effect was mediated by the activation of TLR2 and TLR4 as it was annulled by the addition of anti-TLR2 or anti-TLR4 blocking antibodies. In vivo, we maximized the antitumor activity of IFN¿ co-expressing in the liver a SR-B1 ligand and IFN¿ by adeno-associated viruses. This gene therapy strategy eradicated liver metastases from colon cancer with reduced toxicity. On the other hand, genetic and pharmacological inhibition of SR-B1 blocks the clathrin-dependent interferon receptor recycling pathway with a concomitant reduction in IFN¿ signaling and bioactivity. This effect can be applied to enhance cancer immunotherapy with oncolytic viruses. Indeed, SR-B1 antagonists facilitate replication of oncolytic viruses amplifying their tumoricidal potential. In conclusion, SR-B1 agonists behave as IFN¿ enhancers while SR-B1 inhibitors dampen IFN¿ activity. These results demonstrate that SR-B1 is a suitable pharmacology target to enhance cancer immunotherapy based on IFN¿ and oncolytic viruses.
Autores: Nistal Villan, Estanislao; Poutou Paumier, Yoanna; Rodríguez García, Estefanía; et al.
Revista: PLOS ONE
ISSN 1932-6203  Vol. 11  Nº 3  2016  págs. e0152031
Development of reporter systems for in vivo examination of IFN-ß induction or signaling of type I interferon (IFN-I) pathways is of great interest in order to characterize biological responses to different inducers such as viral infections. Several reporter mice have been developed to monitor the induction of both pathways in response to different agonists. However, alternative strategies that do not require transgenic mice breeding have to date not been reported. In addition, detection of these pathways in vivo in animal species other than mice has not yet been addressed. Herein we describe a simple method based on the use of an adeno-associated viral vector (AAV8-3xIRF-ISRE-Luc) containing an IFN-ß induction and signaling-sensitive promoter sequence controlling the expression of the reporter gene luciferase. This vector is valid for monitoring IFN-I responses in vivo elicited by diverse stimuli in different organs. Intravenous administration of the vector in C57BL/6 mice and Syrian hamsters was able to detect activation of the IFN pathway in the liver upon systemic treatment with different pro-inflammatory agents and infection with Newcastle disease virus (NDV). In addition, intranasal instillation of AAV8-3xIRF-ISRE-Luc showed a rapid and transient IFN-I response in the respiratory tract of mice infected with the influenza A/PR8/34 virus lacking the NS1 protein. In comparison, this response was delayed and exacerbated in mice infected with influenza A/PR/8 wild type virus. In conclusion, the AAV8-3xIRF-ISRE-Luc vector offers the possibility of detecting IFN-I activation in response to different stimuli and in different animal models with no need for reporter transgenic animals.
Autores: Zabaleta Azpiroz, Aintzane; D'Avola, Delia; Echeverria Beistegui, Itziar; et al.
ISSN 2329-0501  Vol. 2  2015  págs. 15006
The lack of antiviral cellular immune responses in patients with chronic hepatitis C virus (HCV) infection suggests that T-cell vaccines may provide therapeutic benefit. Due to the central role that dendritic cells (DC) play in the activation of T-cell responses, our aim was to carry out a therapeutic vaccination clinical trial in HCV patients using DC. Five patients with chronic HCV infection were vaccinated with three doses of 5¿×¿10(6) or 10(7) autologous DC transduced with a recombinant adenovirus encoding NS3 using the adapter protein CFh40L, which facilitates DC transduction and maturation. No significant adverse effects were recorded after vaccination. Treatment caused no changes in serum liver enzymes nor in viral load. Vaccination induced weak but consistent expansion of T-cell responses against NS3 and adenoviral antigens. Patients' DC, as opposed to murine DC or DC from healthy subjects, secreted high IL-10 levels after transduction, inducing the activation of IL-10-producing T cells. IL-10 blockade during vaccine preparation restored its ability to stimulate anti-NS3 Th1 responses. Thus, vaccination with adenovirus-transduced DC is safe and induces weak antiviral immune responses. IL-10 associated with vaccine preparation may be partly responsible for these effects, suggesting that future vaccines should consider concomitant inhibition of this cytokine
Autores: Nistal Villan, Estanislao; Buñuales Aramendía, María; Poutou Paumier, Yoanna; et al.
ISSN 1476-4598  Vol. 14  2015  págs. 210
Background: The limited efficacy of current treatments against pancreatic cancer has prompted the search of new alternatives such as virotherapy. Activation of the immune response against cancer cells is emerging as one of the main mechanisms of action of oncolytic viruses (OV). Direct oncolysis releases tumor antigens, and viral replication within the tumor microenvironment is a potent danger signal. Arming OV with immunostimulatory transgenes further enhances their therapeutic effect. However, standard virotherapy protocols do not take full advantage of OV as cancer vaccines because repeated viral administrations may polarize immune responses against strong viral antigens, and the rapid onset of neutralizing antibodies limits the efficacy of redosing. An alternative paradigm based on sequential combination of antigenically distinct OV has been recently proposed. Methods: We have developed a protocol consisting of sequential intratumor administrations of new Adenovirus (Ad) and Newcastle Disease Virus (NDV)-based OV encoding the immunostimulatory cytokine oncostatin M (OSM). Transgene expression, toxicity and antitumor effect were evaluated using an aggressive orthotopic pancreatic cancer model in Syrian hamsters, which are sensitive to OSM and permissive for replication of both OVs. Results: NDV-OSM was more cytolytic, whereas Ad-OSM caused higher OSM expression in vivo. Both viruses achieved only a marginal antitumor effect in monotherapy. In addition, strong secretion of OSM in serum limited the maximal tolerated dose of Ad-OSM. In contrast, moderate doses of Ad-OSM followed one week later by NDV-OSM were safe, showed a significant antitumor effect and stimulated immune responses against cancer cells. Similar efficacy was observed when the order of virus administrations was reversed. Conclusion: Sequential administration of oncolytic Ad and NDV encoding OSM is a promising approach against pancreatic cancer.
Autores: Nistal Villan, Estanislao; Rodríguez García, Estefanía; Di Scala, Marianna; et al.
ISSN 1662-811X  Vol. 7  Nº 5  2015  págs. 466 - 481
RIG-I-like receptors (RLRs) are cellular sensor proteins that detect certain RNA species produced during viral infections. RLRs activate a signaling cascade that results in the production of IFN-ß as well as several other cytokines with antiviral and proinflammatory activities. We explored the potential of different constructs based on RLRs to induce the IFN-ß pathway and create an antiviral state in type I IFN-unresponsive models. A chimeric construct composed of RIG-I 2CARD and the first 200 amino acids of MAVS (2CARD-MAVS200) showed an enhanced ability to induce IFN-ß when compared to other stimulatory constructs. Furthermore, this human chimeric construct showed a superior ability to activate IFN-ß expression in cells from various species. This construct was found to overcome the restrictions of blocking IFN-ß induction or signaling by a number of viral IFN-antagonist proteins. Additionally, the antiviral activity of this chimera was demonstrated in influenza virus and HBV infection mouse models using adeno-associated virus (AAV) vectors as a delivery vehicle. We propose that AAV vectors expressing 2CARD-MAVS200 chimeric protein can reconstitute IFN-ß induction and recover a partial antiviral state in different models that do not respond to recombinant IFN-ß treatment.
Autores: Moreno Amatria, Esther; Schwartz Mota, Juana; Larrea Leoz, María Esther; et al.
ISSN 1549-9634  Vol. 11  Nº 8  2015  págs. 2003 - 2012
Patients affected by cutaneous leishmaniasis need a topical treatment which cures lesions without leaving scars. Lesions are produced not only by the parasite but also by an uncontrolled and persistent inflammatory immune response. In this study, we proposed the loading of ß-lapachone (ß-LP) in lecithin-chitosan nanoparticles (NP) for targeting the drug to the dermis, where infected macrophages reside, and promote wound healing. Although the loading of ß-LP in NP did not influence the drug antileishmanial activity it was critical to achieve important drug accumulation in the dermis and permeation through the skin. When topically applied in Leishmania major infected BALB/c mice, ß-LP NP achieved no parasite reduction but they stopped the lesion progression. Immuno-histopathological assays in CL lesions and quantitative mRNA studies in draining lymph nodes confirmed that ß-LP exhibited anti-inflammatory activity leading to the down-regulation of IL-1ß and COX-2 expression and a decrease of neutrophils infiltrate.
Autores: Larrea Leoz, María Esther (Autor de correspondencia); Echeverria Beistegui, Itziar; Riezu Boj, José Ignacio; et al.
ISSN 0168-8278  Vol. 60  Nº 3  2014  págs. 482 - 489
BACKGROUND & AIMS: Oncostatin M (OSM) is an inflammatory cytokine which interacts with a heterodimeric receptor formed by gp130 and either OSMRß or LIFR. Here we have analysed OSM and its receptors in livers with chronic hepatitis C (CHC) and studied the factors that regulate this system. METHODS: OSM, OSM receptors and OSM-target molecules were studied by immunohistochemistry and/or qPCR analysis in livers from CHC patients and controls. We determined the production of OSM by CD40L-stimulated antigen presenting cells (APC) and its biological effects on HuH7 cells containing HCV replicon (HuH7 Core-3'). RESULTS: OSM was upregulated in livers with CHC and its production was mapped to CD11c+ cells. OSM levels correlated directly with inflammatory activity and CD40L expression. In vitro studies showed that OSM is released by APC upon interaction with activated CD4+ T cells in a CD40L-dependent manner. Culture of HuH7 Core-3' cells with supernatant from CD40L-stimulated APC repressed HCV replication and induced IL-7 and IL-15R¿. These effects were dampened by antibodies blocking OSM or gp130 and by silencing OSMRß. In CHC livers OSMRß and LIFR were significantly downregulated and their values correlated with those of OSM-induced molecules. Experiments in HuH7 cells showed that impaired STAT3 signaling and exposure to TGFß1, two findings in CHC, are factors involved in repressing OSMRß and LIFR, respectively. CONCLUSIONS: OSM is a cytokine possessing vigorous antiviral and immunostimulatory properties which is released by APC upon interaction with CD40L present on activated CD4+ T cells. In livers with CHC, OSM is overexpressed but its biological activity appears to be hampered because of downregulation of its receptor subunits.
Autores: Larrea Leoz, María Esther (Autor de correspondencia); Riezu Boj, José Ignacio; Aldabe Arregui, Rafael; et al.
Revista: GUT
ISSN 0017-5749  Vol. 63  Nº 4  2014  págs. 665 - 673
Background IL-7 and IL-15 are produced by hepatocytes and are critical for the expansion and function of CD8 T cells. IL-15 needs to be presented by IL-15R¿ for efficient stimulation of CD8 T cells. Methods We analysed the hepatic levels of IL-7, IL-15, IL-15R¿ and interferon regulatory factors (IRF) in patients with chronic hepatitis C (CHC) (78% genotype 1) and the role of IRF1 and IRF2 on IL-7 and IL-15R¿ expression in Huh7 cells with or without hepatitis C virus (HCV) replicon. Results Hepatic expression of both IL-7 and IL-15R¿, but not of IL-15, was reduced in CHC. These patients exhibited decreased hepatic IRF2 messenger RNA levels and diminished IRF2 staining in hepatocyte nuclei. We found that IRF2 controls basal expression of both IL-7 and IL-15R¿ in Huh7 cells. IRF2, but not IRF1, is downregulated in cells with HCV genotype 1b replicon and this was accompanied by decreased expression of IL-7 and IL-15R¿, a defect reversed by overexpressing IRF2. Treating Huh7 cells with IFN¿ plus oncostatin M increased IL-7 and IL-15R¿ mRNA more intensely than either cytokine alone. This effect was mediated by strong upregulation of IRF1 triggered by the combined treatment. Induction of IRF1, IL-7 and IL-15R¿ by IFN¿ plus oncostatin M was dampened in replicon cells but the combination was more effective than either cytokine alone. Conclusions HCV genotype 1 infection downregulates IRF2 in hepatocytes attenuating hepatocellular expression of IL-7 and IL-15R¿. Our data reveal a new mechanism by which HCV abrogates specific T-cell responses and point to a novel therapeutic approach to stimulate anti-HCV immunity.
Autores: Aranda, Alejandro Mario; Bezunartea, Jaione; Casales Zoco, Erkuden; et al.
ISSN 1420-682X  Vol. 71  Nº 23  2014  págs. 4637 - 4651
We report a new method to generate high-expressing mammalian cell lines in a quick and efficient way. For that purpose, we developed a master cell line (MCL) containing an inducible alphavirus vector expressing GFP integrated into the genome. In the MCL, recombinant RNA levels increased >4,600-fold after induction, due to a doxycycline-dependent RNA amplification loop. The MCL maintained inducibility and expression during 50 passages, being more efficient for protein expression than a conventional cell line. To generate new cell lines, mutant LoxP sites were inserted into the MCL, allowing transgene and selection gene exchange by Cre-directed recombination, leading to quick generation of inducible cell lines expressing proteins of therapeutic interest, like human cardiotrophin-1 and oncostatin-M at several mg/l/24 h. These proteins contained posttranslational modifications, showed bioactivity, and were efficiently purified. Remarkably, this system allowed production of toxic proteins, like oncostatin-M, since cells able to express it could be grown to the desired amount before induction. These cell lines were easily adapted to growth in suspension, making this methodology very attractive for therapeutic protein production.
Autores: Arbillaga Lacunza, Leire; Murillo Arbizu, María Teresa; González de la Tajada, Iranzu; et al.
ISSN 1757-6180  Vol. 5  Nº 3  2013  págs. 289 - 305
Background: IFN-alpha 5 has been demonstrated to induce stronger signaling and higher expression of antiviral genes than IFN-alpha 2, which is the current treatment in chronic viral hepatitis. However, there is no specific and validated quantification method in order to conduct kinetic studies as part of the preclinical and clinical evaluation for regulatory purposes. Results: A novel integration of an antiviral assay against the cytopathic effect of the encephalomyocarditis virus in HeLa cells with a very sensitive method for assay processing - the Vialight (R) Plus assay - is presented for IFN-alpha 5 activity quantification. The bioassay has been validated in macaque and human serum and it has been demonstrated to be selective, precise and accurate. Conclusion: The validated bioassay meets suitable acceptance criteria for these types of biological assays.
Autores: Moreno Luqui, Daniel; Balasiddaiah, A.; Lamas Longarela, Óscar; et al.
Revista: PLOS ONE
ISSN 1932-6203  Vol. 8  Nº 9  2013  págs. e74948
It has been shown that the liver of immunodeficient mice can be efficiently repopulated with human hepatocytes when subjected to chronic hepatocellular damage. Mice with such chimeric livers represent useful reagents for medical and clinical studies. However all previously reported models of humanized livers are difficult to implement as they involve cross-breeding of immunodeficient mice with mice exhibiting genetic alterations causing sustained hepatic injury. In this paper we attempted to create chimeric livers by inducing persistent hepatocellular damage in immunodeficient Rag2(-/-) gamma c(-/-) mice using an adenovirus encoding herpes virus thymidine kinase (AdTk) and two consecutive doses of ganciclovir (GCV). We found that this treatment resulted in hepatocellular damage persisting for at least 10 weeks and enabled efficient engraftment and proliferation within the liver of either human or allogenic hepatocytes. Interestingly, while the nodules generated from the transplanted mouse hepatocytes were well vascularized, the human hepatocytes experienced progressive depolarization and exhibited reduced numbers of murine endothelial cells inside the nodules. In conclusion, AdTk/GCV-induced liver damage licenses the liver of immunodeficient mice for allogenic and xenogenic hepatocyte repopulation. This approach represents a simple alternative strategy for chimeric liver generation using immunodeficient mice without additional genetic manipulation of the germ line.
Autores: Sangro Gómez-Acebo, Bruno Carlos; Gomez-Martin C; de la Mata M; et al.
ISSN 0168-8278  Vol. 59  Nº 1  2013  págs. 81-88
Background & Aims: Tremelimumab is a monoclonal antibody that blocks cytotoxic T-lymphocyte-associated antigen 4 (CTLA-4), an inhibitory co-receptor that interferes with T cell activation and proliferation. The purpose of this pilot clinical trial was to test the antitumor and antiviral effect of tremelimumab in patients with hepatocellular carcinoma (HCC) and chronic hepatitis C virus (HCV) infection; and to study the safety of its administration to cirrhotic patients. Methods: Tremelimumab at a dose of 15 mg/kg IV every 90 days was administered until tumor progression or severe toxicity. Twenty patients were assessable for toxicity and viral response and 17 were assessable for tumor response. Most patients were in the advanced stage and 43% had an altered liver function (Child-Pugh class B). Results: A good safety profile was recorded and no patient needed steroids because of severe immune-mediated adverse events. Some patients had a transient albeit intense elevation of transaminases after the first dose, but not following subsequent cycles. Partial response rate was 17.6% and disease control rate was 76.4%. Time to progression was 6.48 months (95% CI 3.95-9.14). A significant drop in viral load was observed while new emerging variants of the hypervariable region 1 of HCV replaced the predominant variants present before therapy, particularly in those patients with a more prominent drop in viral load. This antiviral effect was associated with an enhanced specific anti-HCV immune response. Conclusions: Tremelimumab safety profile and antitumor and antiviral activity, in patients with advanced HCC developed on HCV-induced liver cirrhosis, support further investigation. (C) 2013 European Association for the Study of the Liver. Published by Elsevier B.V. All rights reserved.
Autores: Hervas Stubbs, Sandra; Mancheño, U; Riezu Boj, José Ignacio; et al.
ISSN 0022-1767  Vol. 189  Nº 7  2012  págs.  3299 - 3310
Autores: Van Damme, P.; Lasa Ventura, Marta; Polevoda, B.; et al.
ISSN 0027-8424  Vol. 109  Nº 31  2012  págs. 12449 - 12454
Protein N-terminal acetylation (Nt-acetylation) is an important mediator of protein function, stability, sorting, and localization. Although the responsible enzymes are thought to be fairly well characterized, the lack of identified in vivo substrates, the occurrence of Nt-acetylation substrates displaying yet uncharacterized N-terminal acetyltransferase (NAT) specificities, and emerging evidence of posttranslational Nt-acetylation, necessitate the use of genetic models and quantitative proteomics. NatB, which targets Met-Glu-, Met-Asp-, and Met-Asn-starting protein N termini, is presumed to Nt-acetylate 15% of all yeast and 18% of all human proteins. We here report on the evolutionary traits of NatB from yeast to human and demonstrate that ectopically expressed hNatB in a yNatB-Delta yeast strain partially complements the natB-Delta phenotypes and partially restores the yNatB Nt-acetylome. Overall, combining quantitative N-terminomics with yeast studies and knockdown of hNatB in human cell lines, led to the unambiguous identification of 180 human and 110 yeast NatB substrates. Interestingly, these substrates included Met-Gln- N-termini, which are thus now classified as in vivo NatB substrates. We also demonstrate the requirement of hNatB activity for maintaining the structure and function of actomyosin fibers and for proper cellular migration. In addition, expression of tropomyosin-1 restored the altered focal adhesions and cellular migration defects observed in hNatB-depleted HeLa cells, indicative for the conserved link between NatB, tropomyosin, and actin cable function from yeast to human.
Autores: Otano Andrés, Itziar; Suárez Amarán, Lester; Dotor, J.; et al.
Revista: Hepatology
ISSN 0270-9139  Vol. 56  Nº 2  2012  págs. 474 - 483
Autores: Fioravanti, Jessica; González de la Tajada, Iranzu; Medina Echeverz, José; et al.
Revista: Hepatology
ISSN 0270-9139  Vol. 53  Nº 6  2011  págs. 1864 - 1873
Interferon alpha (IFN alpha) is widely used for the treatment of viral hepatitis but substantial toxicity hampers its clinical use. In this work, we aimed at improving the efficacy of IFN alpha therapy by increasing the IFN alpha half-life and providing l
Autores: Riezu Boj, José Ignacio; Larrea Leoz, María Esther; Aldabe Arregui, Rafael; et al.
ISSN 0168-8278  Vol. 54  Nº 3  2011  págs. 422 - 431
Autores: Diaz-Valdés Farray, Nancy; Manterola Careaga, Lorea; Belsúe Urquizu, Virginia; et al.
ISSN 0270-9139  Vol. 53  Nº 1  2011  págs. 23 - 31
Autores: Tuñón, MJ; San Miguel, B; Crespo, I; et al.
ISSN 0022-538X  Vol. 85  Nº 24  2011  págs. 13124 - 13132
Rabbit hemorrhagic disease virus (RHDV) causes lethal fulminant hepatitis closely resembling acute liver failure (ALF) in humans. In this study, we investigated whether cardiotrophin-1 (CT-1), a cytokine with hepatoprotective properties, could attenuate liver damage and prolong survival in virus-induced ALF. Twenty-four rabbits were infected with 2 x 10(4) hemagglutination units of RHDV. Twelve received five doses of CT-1 (100 mu g/kg) starting at 12 h postinfection (hpi) (the first three doses every 6 h and then two additional doses at 48 and 72 hpi), while the rest received saline. The animals were analyzed for survival, serum biochemistry, and viral load. Another cohort (n = 22) was infected and treated similarly, but animals were sacrificed at 30 and 36 hpi to analyze liver histology, viral load, and the expression of factors implicated in liver damage and repair. All infected rabbits that received saline died by 60 hpi, while 67% of the CT-1-treated animals survived until the end of the study. Treated animals showed improved liver function and histology, while the viral loads were similar. In the livers of CT-1-treated rabbits we observed reduction of oxidative stress, diminished PARP1/2 and JNK activation, and decreased inflammatory reaction, as reflected by reduced expression of tumor necrosis factor alpha, interleukin-1 beta, Toll-like receptor 4, VCAM-1, and MMP-9. In addition, CT-1-treated rabbits exhibited marked upregulation of TIMP-1 and increased expression of cytoprotective and proregenerative growth factors, including platelet-derived growth factor B, epidermal growth factor, platelet-derived growth factor receptor beta, and c-Met. In conclusion, in a lethal form of acute viral hepatitis, CT-1 increases animal survival by attenuating inflammation and activating cytoprotective mechanisms, thus representing a promising therapy for ALF of viral origin.
Autores: Rouzaut Subirá, Ana; Garasa, S.; Teijeira Sánchez, Álvaro; et al.
Revista: European Journal of Immunology
ISSN 0014-2980  Vol. 40  Nº 11  2010  págs. 3054 - 3063
Migration of DC into lymphatic vessels ferries antigenic cargo and pro-inflammatory stimuli into the draining LN. Given that tissues under the influence of viral infections produce type I IFN, it is conceivable that these cytokines enhance DC migration in order to facilitate an antiviral immune response. Cultured lymphatic endothelium monolayers pretreated with TNF-alpha were used to model this phenomenon under inflammatory conditions. DC differentiated in the presence of either IFN-alpha 2b or IFN-alpha 5 showed enhanced adhesion to cultured lymphatic endothelial cells. These pro-adhesive effects were mediated by DC, not the lymphatic endothelium, and correlated with increased DC transmigration across lymphatic endothelial cell monolayers. Transmigration was guided by chemokines acting on DC, and blocking experiments with mAb indicated a role for LFA-1. Furthermore, incubation of DC with IFN-alpha led to the appearance of active conformation epitopes on the CD11a integrin chains expressed by DC. Differentiation of mouse DC in the presence of IFN-alpha also increased DC migration from inflammed footpads toward popliteal LN. Collectively, these results indicate a role for type I IFN in directing DC toward LN under inflammatory conditions.
Autores: Hervas Stubbs, Sandra; Riezu Boj, José Ignacio; González, I; et al.
Revista: European Journal of Immunology
ISSN 0014-2980  Vol. 40  Nº 12  2010  págs. 3389 - 3402



Trabajo Fin de Grado (Gr.Bioquímica). 
Universidad de Navarra - Facultad de Ciencias.

Trabajo Fin de Grado (Gr.Bioquímica). 
Universidad de Navarra - Facultad de Ciencias.

Genética Clínica B (Medicina). 
Universidad de Navarra - Facultad de Ciencias.

Métodos instrumentales en bioquímica y biología molecular I (F.Ciencias). 
Universidad de Navarra - Facultad de Ciencias.

Genética Clínica (Medicina). 
Universidad de Navarra - Facultad de Ciencias.