Nuestros investigadores

Celia Fernández Rubio

Publicaciones científicas más recientes (desde 2010)

Autores: Fernández, Celia; 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: Moreno, Esther; 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: Fernández, 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: Fernández, Celia; et al.
ISSN 0002-9637  Vol. 95  Nº 5  2017  págs. 548 - 548
Autores: Fernández, Celia; Campbell, D.; et al.
ISSN 0066-4804  Vol. 59  Nº 9  2015  págs. 5705 - 5713
The generation of new antileishmanial drugs has become a priority. Selenium and its derivatives stand out as having promising leishmanicidal activity. In fact, some parasites express selenoproteins and metabolize selenium. Recently, selenium derivatives have shown the potential to reduce parasitemia, clinical manifestations, and mortality in parasite-infected mice. In this paper, after selecting four candidates according to drug similarity parameters, we observed that two of them, called compounds 2b [methyl-N,N¿-di(thien-2-ylcarbonyl)-imidoselenocarbamate] and 4b [methyl-N,N¿-di(5-nitrothien-3-ylcarbonyl)-imidoselenocarbamate], exhibit low 50% inhibitory concentrations (IC50s) (<3 ¿M) and good selectivity indexes (SIs) (>5) in Leishmania major promastigotes and lack toxicity on macrophages. In addition, in analysis of their therapeutic potential against L. major in vitro infection, both compounds display a dramatic reduction of amastigote burden (~80%) with sublethal concentrations. Furthermore, in macrophages, these selenocompounds induce nitric oxide production, which has been described to be critical for defense against intracellular pathogens. Compounds 2b and 4b were demonstrated to cause cell cycle arrest in G1 . Interestingly, evaluation of expression of genes related to proliferation (PCNA), treatment resistance (ABC transporter and alpha-tubulin), and virulence (quinonoid dihydropteridine reductase [QDPR]) showed several alterations in gene expression profiling. All these results prompt us to propose both compounds as candidates to treat leishmanial infections.
Autores: Moreno, Esther; Fernández, Celia; et al.
ISSN 1742-5247  Vol. 11  Nº 4  2014  págs. 579 - 597
Introduction: Cutaneous and mucocutaneous leishmaniasis are major tropical skin diseases. Topical treatment is currently limited to the least severe forms of cutaneous leishmaniasis (CL) without risk of dissemination. It is also recommended in combination with systemic therapy for more severe forms. Progresses in this modality of treatment are hindered by the heterogeneity of the disease and shortcomings in the clinical trials. Areas covered: This review overlooks three major modalities of topical therapies in use or under investigation against CL: chemotherapy, photodynamic therapy and immunotherapy; either with older compounds such as paramonnycin or more recent nitric oxide donors, antimicrobial peptides or silver derivatives. The advantages and limitations of their administration with newer formulation strategies such as nanoparticles (NPs) are discussed. Expert opinion: The efficacy of a topical treatment against CL depends not only on the intrinsic antileishmanial activity of the drug but also on the amount of drug available in the dermis. NPs as sustained release systems and permeation enhancers could favour the creation of a drug reservoir in the dermis. Additionally, certain NPs have immunomodulatory properties or wound healing capabilities of benefit in CL treatment. Pending task is the selective delivery of active compounds to intracellular amastigotes, because even small NPs are unable to penetrate deeply into the skin to encounter infected macrophages (except in ulcerative lesions).
Autores: Moreno, Esther; Fernández, Celia; et al.
ISSN 0928-0987  Vol. 62  2014  págs. 309 - 316
Topical therapy is the ideal outpatient treatment of cutaneous leishmaniasis (CL) because of the ease of administration and lower cost. It could be suitable as monotherapy for localized cutaneous leishmaniasis (LCL) or in combination with systemic therapies for more severe forms of the disease. Although paromomycin (PM) ointment can be recommended for the treatment of LCL caused by Leishmaniamajor, a more effective topical treatment should be achieved regarding the physicochemical properties of this aminoglucoside and its rather poor intrinsic antileishmanial activity, that hampers the accumulation of enough amount of drug in the dermis (where the infected macrophages home) to exert its activity. In this work, we determined a 50% effective dose of 5.6 ¿M for a novel compound, bis-4-aminophenyldiselenide, against L. major intracellular amastigotes. This compound and PM were formulated in chitosan hydrogels and ex vivo permeation and retention studies in the different skin layers were performed with pig ear skin in Franz diffusion cells. The results showed that less than 2¿4% of the diselenide drug penetrated and permeated through the skin. In contrast, the percentage of PM penetration was about 25¿60% without important retention in the skin. When topically applied to lesions of L. major infected BALB/c mice, the novel diselenide chitosan formulation was unable to slow lesion progression and reduce parasite burden. Considerations during the process of novel drug development and