Staff member

Elena Lantero Escolar

Postdoctoral Researcher
+34 934 037 180
Staff member publications

Lantero, E., Belavilas-Trovas, A., Biosca, A., Recolons, P., Moles, E., Sulleiro, E., Zarzuela, F., Ávalos-Padilla, Y., Ramírez, M., Fernàndez-Busquets, X., (2020). Development of DNA aptamers against Plasmodium falciparum blood stages using cell-systematic evolution of ligands by exponential enrichment Journal of biomedical nanotechnology Journal of Biomedical Nanotechnology , 16, (3), 315-334

New biomarkers have to be developed in order to increase the performance of current antigen-based malaria rapid diagnosis. Antibody production often involves the use of laboratory animals and is time-consuming and costly, especially when the target is Plasmodium, whose variable antigen expression complicates the development of long-lived biomarkers. To circumvent these obstacles, we have applied the Systematic Evolution of Ligands by EXponential enrichment method to the rapid identification of DNA aptamers against Plasmodium falciparum-infected red blood cells (pRBCs). Five 70 b-long ssDNA sequences, and their shorter forms without the flanking PCR primer-binding regions, have been identified having a highly specific binding of pRBCs versus non-infected erythrocytes. Structural analysis revealed G-enriched sequences compatible with the formation of G-quadruplexes. The selected aptamers recognized intracellular epitopes with apparent Kds in the μM range in both fixed and non-fixed saponin-permeabilized pRBCs, improving >30-fold the pRBC detection in comparison with aptamers raised against Plasmodium lactate dehydrogenase, the gold standard antigen for current malaria diagnostic tests. In thin blood smears of clinical samples the aptamers reported in this work specifically bound all P. falciparum stages versus non-infected erythrocytes, and also detected early and late stages of the human malaria parasites Plasmodium vivax, Plasmodium ovale and Plasmodium malariae. The results are discussed in the context of their potential application in future malaria diagnostic devices.

Borgheti-Cardoso, L. N., Kooijmans, S. A. A., Gutiérrez Chamorro, L., Biosca, A., Lantero, E., Ramírez, M., Avalos-Padilla, Y., Crespo, I., Fernández, I., Fernandez-Becerra, C., del Portillo, H. A., Fernàndez-Busquets, X., (2020). Extracellular vesicles derived from Plasmodium-infected and non-infected red blood cells as targeted drug delivery vehicles International Journal of Pharmaceutics 587, 119627

Among several factors behind drug resistance evolution in malaria is the challenge of administering overall doses that are not toxic for the patient but that, locally, are sufficiently high to rapidly kill the parasites. Thus, a crucial antimalarial strategy is the development of drug delivery systems capable of targeting antimalarial compounds to Plasmodium with high specificity. In the present study, extracellular vesicles (EVs) have been evaluated as a drug delivery system for the treatment of malaria. EVs derived from naive red blood cells (RBCs) and from Plasmodium falciparum-infected RBCs (pRBCs) were isolated by ultrafiltration followed by size exclusion chromatography. Lipidomic characterization showed that there were no significant qualitative differences between the lipidomic profiles of pRBC-derived EVs (pRBC-EVs) and RBC-derived EVs (RBC-EVs). Both EVs were taken up by RBCs and pRBCs, although pRBC-EVs were more efficiently internalized than RBC-EVs, which suggested their potential use as drug delivery vehicles for these cells. When loaded into pRBC-EVs, the antimalarial drugs atovaquone and tafenoquine inhibited in vitro P. falciparum growth more efficiently than their free drug counterparts, indicating that pRBC-EVs can potentially increase the efficacy of several small hydrophobic drugs used for the treatment of malaria.

Keywords: Antimalarial drugs, Drug delivery, Extracellular vesicles, Malaria, Plasmodium falciparum

Lantero, E., Fernandes, J., Aláez-Versón, C. R., Gomes, J., Silveira, H., Nogueira, F., Fernàndez-Busquets, X., (2020). Heparin administered to anopheles in membrane feeding assays blocks plasmodium development in the mosquito Biomolecules 10, (8), 1136

Innovative antimalarial strategies are urgently needed given the alarming evolution of resistance to every single drug developed against Plasmodium parasites. The sulfated glycosaminoglycan heparin has been delivered in membrane feeding assays together with Plasmodium berghei-infected blood to Anopheles stephensi mosquitoes. The transition between ookinete and oocyst pathogen stages in the mosquito has been studied in vivo through oocyst counting in dissected insect midguts, whereas ookinete interactions with heparin have been followed ex vivo by flow cytometry. Heparin interferes with the parasite’s ookinete–oocyst transition by binding ookinetes, but it does not affect fertilization. Hypersulfated heparin is a more efficient blocker of ookinete development than native heparin, significantly reducing the number of oocysts per midgut when offered to mosquitoes at 5 µg/mL in membrane feeding assays. Direct delivery of heparin to mosquitoes might represent a new antimalarial strategy of rapid implementation, since it would not require clinical trials for its immediate deployment.

Keywords: Anopheles, Antimalarial drugs, Heparin, Malaria, Mosquito, Ookinete, Plasmodium, Transmission blocking

Borgheti-Cardoso, L. N., San Anselmo, M., Lantero, E., Lancelot, A., Serrano, J. L., Hernández-Ainsa, S., Fernàndez-Busquets, X., Sierra, T., (2020). Promising nanomaterials in the fight against malaria Journal of Materials Chemistry B 8, (41), 9428-9448

For more than one hundred years, several treatments against malaria have been proposed but they have systematically failed, mainly due to the occurrence of drug resistance in part resulting from the exposure of the parasite to low drug doses. Several factors are behind this problem, including (i) the formidable barrier imposed by the Plasmodium life cycle with intracellular localization of parasites in hepatocytes and red blood cells, (ii) the adverse fluidic conditions encountered in the blood circulation that affect the interaction of molecular components with target cells, and (iii) the unfavorable physicochemical characteristics of most antimalarial drugs, which have an amphiphilic character and can be widely distributed into body tissues after administration and rapidly metabolized in the liver. To surpass these drawbacks, rather than focusing all efforts on discovering new drugs whose efficacy is quickly decreased by the parasite's evolution of resistance, the development of effective drug delivery carriers is a promising strategy. Nanomaterials have been investigated for their capacity to effectively deliver antimalarial drugs at local doses sufficiently high to kill the parasites and avoid drug resistance evolution, while maintaining a low overall dose to prevent undesirable toxic side effects. In recent years, several nanostructured systems such as liposomes, polymeric nanoparticles or dendrimers have been shown to be capable of improving the efficacy of antimalarial therapies. In this respect, nanomaterials are a promising drug delivery vehicle and can be used in therapeutic strategies designed to fight the parasite both in humans and in the mosquito vector of the disease. The chemical analyses of these nanomaterials are essential for the proposal and development of effective anti-malaria therapies. This review is intended to analyze the application of nanomaterials to improve the drug efficacy on different stages of the malaria parasites in both the human and mosquito hosts.

Manconi, M., Manca, M. L., Escribano-Ferrer, E., Coma-Cros, E. M., Biosca, A., Lantero, E., Fernàndez-Busquets, X., Fadda, A. M., Caddeo, C., (2019). Nanoformulation of curcumin-loaded eudragit-nutriosomes to counteract malaria infection by a dual strategy: Improving antioxidant intestinal activity and systemic efficacy International Journal of Pharmaceutics 556, 82-88

In this paper, nutriosomes (phospholipid vesicles associated with Nutriose® FM06) were modified to obtain new systems aimed at enhancing the efficacy of curcumin in counteracting malaria infection upon oral administration. Eudragit® L100, a pH-sensitive co-polymer, was added to these vesicles, thus obtaining eudragit-nutriosomes, to improve their in vivo performances. Liposomes without eudragit and nutriose were also prepared as a reference. Cryo-TEM images showed the formation of multicompartment vesicles, with mean diameter around 300 nm and highly negative zeta potential. Vesicles were stable in fluids mimicking the gastro-intestinal content due to the high phospholipid concentration and the presence of gastro-resistant eudragit and digestion-resistant nutriose. Eudragit-nutriosomes disclosed promising performances in vitro and in vivo: they maximized the ability of curcumin to counteract oxidative stress in intestinal cells (Caco-2), which presumably reinforced its systemic efficacy. Orally-administered curcumin-loaded eudragit-nutriosomes increased significantly the survival of malaria-infected mice relative to free curcumin-treated controls.

Keywords: Eudragit® L100, Nutriose® FM06, Nutriosomes, Curcumin, Oral administration, Malaria

Aguiar, L., Biosca, A., Lantero, E., Gut, J., Vale, N., Rosenthal, P. J., Nogueira, F., Andreu, D., Fernàndez-Busquets, X., Gomes, P., (2019). Coupling the antimalarial cell penetrating peptide TP10 to classical antimalarial drugs primaquine and chloroquine produces strongly hemolytic conjugates Molecules 24, (24), 4559

Recently, we disclosed primaquine cell penetrating peptide conjugates that were more potent than parent primaquine against liver stage Plasmodium parasites and non-toxic to hepatocytes. The same strategy was now applied to the blood-stage antimalarial chloroquine, using a wide set of peptides, including TP10, a cell penetrating peptide with intrinsic antiplasmodial activity. Chloroquine-TP10 conjugates displaying higher antiplasmodial activity than the parent TP10 peptide were identified, at the cost of an increased hemolytic activity, which was further confirmed for their primaquine analogues. Fluorescence microscopy and flow cytometry suggest that these drug-peptide conjugates strongly bind, and likely destroy, erythrocyte membranes. Taken together, the results herein reported put forward that coupling antimalarial aminoquinolines to cell penetrating peptides delivers hemolytic conjugates. Hence, despite their widely reported advantages as carriers for many different types of cargo, from small drugs to biomacromolecules, cell penetrating peptides seem unsuitable for safe intracellular delivery of antimalarial aminoquinolines due to hemolysis issues. This highlights the relevance of paying attention to hemolytic effects of cell penetrating peptide-drug conjugates.

Keywords: Antimalarial, Cell penetrating peptide, Chloroquine, Erythrocyte fluorescence, Flow cytometry, Hemolysis, Microscopy, Plasmodium, Primaquine, Red blood cell

Martí Coma-Cros, Elisabet, Biosca, Arnau, Lantero, Elena, Manca, Maria, Caddeo, Carla, Gutiérrez, Lucía, Ramírez, Miriam, Borgheti-Cardoso, Livia, Manconi, Maria, Fernàndez-Busquets, Xavier, (2018). Antimalarial activity of orally administered curcumin incorporated in Eudragit®-containing liposomes International Journal of Molecular Sciences 19, (5), 1361

Curcumin is an antimalarial compound easy to obtain and inexpensive, having shown little toxicity across a diverse population. However, the clinical use of this interesting polyphenol has been hampered by its poor oral absorption, extremely low aqueous solubility and rapid metabolism. In this study, we have used the anionic copolymer Eudragit® S100 to assemble liposomes incorporating curcumin and containing either hyaluronan (Eudragit-hyaluronan liposomes) or the water-soluble dextrin Nutriose® FM06 (Eudragit-nutriosomes). Upon oral administration of the rehydrated freeze-dried nanosystems administered at 25/75 mg curcumin·kg−1·day−1, only Eudragit-nutriosomes improved the in vivo antimalarial activity of curcumin in a dose-dependent manner, by enhancing the survival of all Plasmodium yoelii-infected mice up to 11/11 days, as compared to 6/7 days upon administration of an equal dose of the free compound. On the other hand, animals treated with curcumin incorporated in Eudragit-hyaluronan liposomes did not live longer than the controls, a result consistent with the lower stability of this formulation after reconstitution. Polymer-lipid nanovesicles hold promise for their development into systems for the oral delivery of curcumin-based antimalarial therapies.

Keywords: Malaria, Curcumin, Nanomedicine, Oral administration, Lipid nanovesicles, Eudragit, Nutriose, Hyaluronan, Plasmodium yoelii

Aláez-Versón, C. R., Lantero, E., Fernàndez-Busquets, X., (2017). Heparin: New life for an old drug Nanomedicine 12, (14), 1727-1744

Heparin is one of the oldest drugs, which nevertheless remains in widespread clinical use as an inhibitor of blood coagulation. The history of its identification a century ago unfolded amid one of the most fascinating scientific controversies turning around the distribution of credit for its discovery. The composition, purification and structure-function relationship of this naturally occurring glycosaminoglycan regarding its classical role as anticoagulant will be dealt with before proceeding to discuss its therapeutic potential in, among other, inflammatory and infectious disease, cancer treatment, cystic fibrosis and Alzheimer's disease. The first bibliographic reference hit using the words 'nanomedicine' and 'heparin' is as recent as 2008. Since then, nanomedical applications of heparin have experienced an exponential growth that will be discussed in detail, with particular emphasis on its antimalarial activity. Some of the most intriguing potential applications of heparin nanomedicines will be exposed, such as those contemplating the delivery of drugs to the mosquito stages of malaria parasites.

Keywords: Anopheles, Antimalarial drugs, Heparin, Malaria, Mosquitoes, Nanomedicine, Nanotechnology, Plasmodium, Targeted drug delivery