Papers by Catarina Bourgard
Research Square (Research Square), Feb 20, 2024
Malaria remains a signi cant public health challenge, with Plasmodium vivax being the species res... more Malaria remains a signi cant public health challenge, with Plasmodium vivax being the species responsible for the most prevalent form of the disease. Given the limited therapeutic options available, the search for new antimalarials against P. vivax is urgent. This study aims to identify new inhibitors for P. vivax N-myristoyltransferase (PvNMT), an essential drug target against malaria. Through a validated virtual screening campaign, we prioritized 23 candidates for further testing. In the yeast NMT system, seven compounds exhibit a potential inhibitor phenotype. In vitro antimalarial phenotypic assays con rmed the activity of four candidates while demonstrating an absence of cytotoxicity. Enzymatic assays reveal LabMol-394 as the most promising inhibitor, displaying selectivity against the parasite and a strong correlation within the yeast system. Furthermore, molecular dynamics simulations shed some light into its binding mode. This study constitutes a substantial contribution to the exploration of a selective quinoline scaffold and provides valuable insights into the development of new antimalarial candidates.
Antimicrobial Agents and Chemotherapy
Drug resistance to commercially available antimalarials is a major obstacle in malaria control an... more Drug resistance to commercially available antimalarials is a major obstacle in malaria control and elimination, creating the need to find new antiparasitic compounds with novel mechanisms of action. The success of kinase inhibitors for oncological treatments has paved the way for the exploitation of protein kinases as drug targets in various diseases, including malaria. Casein kinases are ubiquitous serine/threonine kinases involved in a wide range of cellular processes such as mitotic checkpoint signaling, DNA damage response, and circadian rhythm. In Plasmodium , it is suggested that these protein kinases are essential for both asexual and sexual blood-stage parasites, reinforcing their potential as targets for multi-stage antimalarials. To identify new putative Pf CK2α inhibitors, we utilized an in silico chemogenomic strategy involving virtual screening with docking simulations and quantitative structure-activity relationship predictions. Our investigation resulted in the discov...
The enzyme deoxyhypusine synthase (DHS) catalyzes the first step in the post-translational modifi... more The enzyme deoxyhypusine synthase (DHS) catalyzes the first step in the post-translational modification of the eukaryotic translation factor 5A (eIF5A). This is the only protein known to contain the amino acid hypusine, which results from this modification. Both eIF5A and DHS are essential for cell viability in eukaryotes, and inhibiting DHS can be a promising strategy for the development of new therapeutic alternatives. The human and parasitic orthologous proteins are different enough to render selective targeting against infectious diseases; however, no DHS inhibitor selective for the parasite ortholog has previously been reported. Here, we established a yeast surrogate genetics platform to identify inhibitors of DHS from Plasmodium vivax, one of the major causative agents of malaria. We constructed genetically modified Saccharomyces cerevisiae strains expressing DHS genes from Homo sapiens (HsDHS) or P. vivax (PvDHS) in place of the endogenous DHS gene from S. cerevisiae. This ne...
Journal of Natural Products, Nov 22, 2021
Five new cyclohexene derivatives, dipandensin A and B (1 and 2) and pandensenols A−C (3−5), and 1... more Five new cyclohexene derivatives, dipandensin A and B (1 and 2) and pandensenols A−C (3−5), and 16 known secondary metabolites (6−21) were isolated from the methanolsoluble extracts of the stem and root barks of Uvaria pandensis. The structures were characterized by NMR spectroscopic and mass spectrometric analyses, and that of 6-methoxyzeylenol (6) was further confirmed by single-crystal X-ray crystallography, which also established its absolute configuration. The isolated metabolites were evaluated for antibacterial activity against the Gram-positive bacteria Bacillus subtilis and Staphylococcus epidermidis and the Gram-negative bacteria Enterococcus raf f inosus, Escherichia coli, Paraburkholderia caledonica, Pectobacterium carotovorum, and Pseudomonas putida, as well as for cytotoxicity against the MCF-7 human breast cancer cell line. A mixture of uvaretin (20) and isouvaretin (21) exhibited significant antibacterial activity against B. subtilis (EC 50 8.7 μM) and S. epidermidis (IC 50 7.9 μM). (8′α,9′β-Dihydroxy)-3-farnesylindole (12) showed strong inhibitory activity (EC 50 9.8 μM) against B. subtilis, comparable to the clinical reference ampicillin (EC 50 17.9 μM). None of the compounds showed relevant cytotoxicity against the MCF-7 human breast cancer cell line.
Na vã tentativa de incluir, neste pequeno espaço, a minha sincera e sentida gratidão a todos quan... more Na vã tentativa de incluir, neste pequeno espaço, a minha sincera e sentida gratidão a todos quantos verdadeiramente contribuíram e impactaram pessoal e profissionalmente nestes últimos cinco anos, começo por agradecer: Ao Prof. Dr. Fabio T. M. Costa, que apostou e confiou nas minhas capacidades de adaptação ao desconhecido e de trabalho numa área de pesquisa tão desafiadora quanto motivante, como é a malária. Obrigada pela orientação e apoio sempre presentes, e além disso, por promover todo um conjunto de colaborações científicas, incentivando-me a buscá-las de forma independente, tanto no Brasil como por esse Mundo fora. Levo como lição o seu exemplo de capacidade de promoção da cooperação e divulgação da pesquisa científica, que espero continuar a fazer por muitos e bons anos. À Profª. Drª. Letusa Albrecht, minha co-orientadora implacável, sempre exigindo mais e o melhor de mim, e acima de tudo uma verdadeira amiga, ensinando-me a ser positiva e a dar a volta por cima, principalmente quando "os ventos não estavam de feição". À Profª. Drª. Stefanie Lopes, a minha segunda co-orientadora que me abriu as portas de Manaus e me ensinou a fazer trabalho de campo "como deve ser!". Minha amiga do coração que me "deu uma família adotiva" quando o meu coração saudoso mais precisou. Muito obrigada aos três, por terem dado origem, promovido a continuidade e apoiarem até ao fim este projeto arriscado e ambicioso. Aos membros da comissão da qualificação e defesa, Prof.
Social Science Research Network, 2022
Three new oxygenated cyclohexene derivatives, pandensenol D - F (1-3), two new flavanoids, panden... more Three new oxygenated cyclohexene derivatives, pandensenol D - F (1-3), two new flavanoids, pandensone A and B (4-5), and seven known compounds (6-12) were isolated from the methanol extract of the leaves of Uvaria pandensis Verdc. (Annonaceae). The structures were characterized by NMR spectroscopic and mass spectrometric analyses. The isolated metabolites were evaluated for their antibacterial activity against the Gram-positive bacteria Bacillus subtilis and Staphylococcus epidermidis and the Gram-negative bacteria Enterococcus raffinosus, Escherichia coli, Paraburkholderia caledonica, Pectobacterium carotovorum and Pseudomonas putida, and for cytotoxicity against the MCF-7 human breast cancer cell line. Out of the tested compounds, pandensenol D (1) and (6',7'-dihydro-8'α,9'β-dihydroxy)-3-farnesylindole (12) showed weak whereas (8'α,9'β-dihydroxy)-3-farnesylindole (11) strong activity against B. subtilis. Four of the isolated compounds (1, 4, 11 and 12) showed moderate cytotoxicity against MCF-7 breast cancer cells (EC50 > 100 μM).
Zenodo (CERN European Organization for Nuclear Research), Aug 26, 2021
Five new cyclohexene derivatives, dipandensin A and B (1 and 2) and pandensenols A−C (3−5), and 1... more Five new cyclohexene derivatives, dipandensin A and B (1 and 2) and pandensenols A−C (3−5), and 16 known secondary metabolites (6−21) were isolated from the methanolsoluble extracts of the stem and root barks of Uvaria pandensis. The structures were characterized by NMR spectroscopic and mass spectrometric analyses, and that of 6-methoxyzeylenol (6) was further confirmed by single-crystal X-ray crystallography, which also established its absolute configuration. The isolated metabolites were evaluated for antibacterial activity against the Gram-positive bacteria Bacillus subtilis and Staphylococcus epidermidis and the Gram-negative bacteria Enterococcus raf f inosus, Escherichia coli, Paraburkholderia caledonica, Pectobacterium carotovorum, and Pseudomonas putida, as well as for cytotoxicity against the MCF-7 human breast cancer cell line. A mixture of uvaretin (20) and isouvaretin (21) exhibited significant antibacterial activity against B. subtilis (EC 50 8.7 μM) and S. epidermidis (IC 50 7.9 μM). (8′α,9′β-Dihydroxy)-3-farnesylindole (12) showed strong inhibitory activity (EC 50 9.8 μM) against B. subtilis, comparable to the clinical reference ampicillin (EC 50 17.9 μM). None of the compounds showed relevant cytotoxicity against the MCF-7 human breast cancer cell line.
NMR raw data for 8 isolated natural products, and the NMReDATA for the new compounds <strong&g... more NMR raw data for 8 isolated natural products, and the NMReDATA for the new compounds <strong>1</strong> and <strong>2</strong>.
Zenodo (CERN European Organization for Nuclear Research), Oct 16, 2022
MSystems, Dec 21, 2021
The ongoing COVID-19 pandemic urges searches for antiviral agents that can block infection or ame... more The ongoing COVID-19 pandemic urges searches for antiviral agents that can block infection or ameliorate its symptoms. Using dissimilar search strategies for new antivirals will improve our overall chances of finding effective treatments. Here, we have established an experimental platform for screening of small molecule inhibitors of the SARS-CoV-2 main protease in Saccharomyces cerevisiae cells, genetically engineered to enhance cellular uptake of small molecules in the environment. The system consists of a fusion of the Escherichia coli toxin MazF and its antitoxin MazE, with insertion of a protease cleavage site in the linker peptide connecting the MazE and MazF moieties. Expression of the viral protease confers cleavage of the MazEF fusion, releasing the MazF toxin from its antitoxin, resulting in growth inhibition. In the presence of a small molecule inhibiting the protease, cleavage is blocked and the MazF toxin remains inhibited, promoting growth. The system thus allows positive selection for inhibitors. The engineered yeast strain is tagged with a fluorescent marker protein, allowing precise monitoring of its growth in the presence or absence of inhibitor. We detect an established main protease inhibitor by a robust growth increase, discernible down to 1 mM. The system is suitable for robotized large-scale screens. It allows in vivo evaluation of drug candidates and is rapidly adaptable for new variants of the protease with deviant site specificities. IMPORTANCE The COVID-19 pandemic may continue for several years before vaccination campaigns can put an end to it globally. Thus, the need for discovery of new antiviral drug candidates will remain. We have engineered a system in yeast cells for the detection of small molecule inhibitors of one attractive drug target of SARS-CoV-2, its main protease, which is required for viral replication. The ability to detect inhibitors in live cells brings the advantage that only compounds capable of entering the cell and remain stable there will score in the system. Moreover, because of its design in yeast cells, the system is rapidly adaptable for tuning the detection level and eventual modification of the protease cleavage site in the case of future mutant variants of the SARS-CoV-2 main protease or even for other proteases.
Journal of Natural Products, Apr 12, 2023
Zenodo (CERN European Organization for Nuclear Research), Sep 19, 2020
Two new prenylated dihydrochalcones (1,2) and eighteen known secondary metabolites (3− 20) were i... more Two new prenylated dihydrochalcones (1,2) and eighteen known secondary metabolites (3− 20) were isolated from the CH 2 Cl 2-MeOH (1:1) extracts of the roots, the stem bark and the leaves of Eriosema montanum Baker f. (Leguminosae). The structures of the isolated compounds were characterized by NMR, IR, and UV spectroscopic and mass spectrometric analyses. The structures of compounds 5, 10, 11 and 13 were confirmed by single crystal X-ray diffraction. The antibacterial activity of the crude extracts and the isolated constituents were established against Gram-positive and Gram-negative bacteria. Among the tested compounds, 1-4 and 10 showed strong activity against the Gram-positive bacterium Bacillus subtilis with minimum inhibitory concentration (MIC) ranging from 3.1 to 8.9 μM, as did the leaf crude extract with an MIC of 3.0 μg/mL. None of the crude extracts nor the isolated compounds were active against Escherichia coli. Compounds 1, 3 and 4 showed higher cytotoxicity, evaluated against the human breast cancer cell line MCF-7, with EC 50 of 7.0, 18.0 and 18.0 μM, respectively. These findings contribute to the phytochemical understanding of the genus Eriosema, and highlight the pharmaceutical potential of prenylated dihydrochalcones.
Zenodo (CERN European Organization for Nuclear Research), Dec 29, 2021
NMR raw data (FIDs) for the natural products isolated from the leaves of Uvaria pandensis
Fitoterapia, Feb 1, 2022
The CH2Cl2/MeOH (1:1) extract of the stems of Tephrosia uniflora yielded the new β-hydroxydihydro... more The CH2Cl2/MeOH (1:1) extract of the stems of Tephrosia uniflora yielded the new β-hydroxydihydrochalcone (S)-elatadihydrochalcone-2'-methyl ether (1) along with the three known compounds elongatin (2), (S)-elatadihydrochalcone (3), and tephrosin (4). The structures were elucidated by NMR spectroscopic and mass spectrometric data analyses. Elongatin (2) showed moderate antibacterial activity (EC50 of 25.3 μM and EC90 of 32.8 μM) against the Gram-positive bacterium Bacilus subtilis, and comparable toxicity against the MCF-7 human breast cancer cell line (EC50 of 41.3 μM). Based on the comparison of literature and predicted data with that obtained experimentally, we propose the revision of the structure of three β-hydroxydihydrochalcones to flavanones.
Journal of Natural Products, Jan 29, 2021
Two new biflavanones (1 and 2), three new bichalconoids (3−5), and 11 known flavonoid analogues (... more Two new biflavanones (1 and 2), three new bichalconoids (3−5), and 11 known flavonoid analogues (6−16) were isolated from the stem bark extract (CH 3 OH−CH 2 Cl 2 , 7:3, v/v) of Ochna holstii. The structures of the isolated metabolites were elucidated by NMR spectroscopic and mass spectrometric analyses. The crude extract and the isolated metabolites were evaluated for antibacterial activity against Bacillus subtilis (Grampositive) and Escherichia coli (Gram-negative) as well as for cytotoxicity against the MCF-7 human breast cancer cell line. The crude extract and holstiinone A (1) exhibited moderate antibacterial activity against B. subtilis with MIC values of 9.1 μg/mL and 14 μM, respectively. The crude extract and lophirone F (14) showed cytotoxicity against MCF-7 with EC 50 values of 11 μg/mL and 24 μM, respectively. The other isolated metabolites showed no significant antibacterial activities (MIC > 250 μM) and cytotoxicities (EC 50 ≥ 350 μM).
Scientific Reports, Mar 3, 2021
Plasmodium vivax is a world-threatening human malaria parasite, whose biology remains elusive. Th... more Plasmodium vivax is a world-threatening human malaria parasite, whose biology remains elusive. The unavailability of in vitro culture, and the difficulties in getting a high number of pure parasites makes RNA isolation in quantity and quality a challenge. Here, a methodological outline for RNAseq from P. vivax isolates with low parasitemia is presented, combining parasite maturation and enrichment with efficient RNA extraction, yielding ~ 100 pg.µL −1 of RNA, suitable for SMART-Seq Ultra-Low Input RNA library and Illumina sequencing. Unbiased coding transcriptome of ~ 4 M reads was achieved for four patient isolates with ~ 51% of transcripts mapped to the P. vivax P01 reference genome, presenting heterogeneous profiles of expression among individual isolates. Amongst the most transcribed genes in all isolates, a parasite-staged mixed repertoire of conserved parasite metabolic, membrane and exported proteins was observed. Still, a quarter of transcribed genes remain functionally uncharacterized. In parallel, a P. falciparum Brazilian isolate was also analyzed and 57% of its transcripts mapped against IT genome. Comparison of transcriptomes of the two species revealed a common trophozoite-staged expression profile, with several homologous genes being expressed. Collectively, these results will positively impact vivax research improving knowledge of P. vivax biology. Plasmodium vivax is the most prevalent malaria parasite outside Sub-Saharan Africa, causing the most geographically widespread type of malaria, placing millions of people at risk of infection 1. Infection occurs in genetically distinct populations with heterogeneous resistance to chloroquine, probably as a result of individual responses in a host-parasite relation 2-5. Severe clinical complications, although scarce 6 , have been of great concern. Nevertheless, the lack of a reliable in vitro system for long term P. vivax culture 7,8 restricts the study of its biology to endemic referral hospitals. The P. vivax Salvador-1 (Sal-1) primate adapted strain, sequenced more than a decade ago 9 , has opened new possibilities for molecular biology studies and is still currently being used as the reference genome 10,11. A recent publication of the P. vivax P01 genome with improved scaffold assembly 12 , lead to meaningful insights into P. vivax biology through the genomic and transcriptomic data. There are many ongoing transcriptome studies underlying several aspects of P. vivax pathogenesis, such as drug resistance 13,14 , disease severity 15 , the active sporozoite 16 versus dormant liver-stage 14 and/or other parasite blood stages 17-19 , and gametocyte differentiation 20,21. Moreover, comparative transcriptome analysis of P. falciparum 22 and P. vivax 19 would be key to access the biological and clinical differences between these human malaria parasite species 8 , impacting considerably on drug and vaccine design. The capacity to isolate, enrich and mature ex vivo P. vivax clinical isolates 23-25 opened new avenues for high-throughput transcriptome sequencing analyses 19,26-28. However, the very low parasitemias 29 and the
Zenodo (CERN European Organization for Nuclear Research), Oct 16, 2022
NMR data (FIDs, NMReDATA) for the isolated compounds
European Journal of Organic Chemistry
Additional file 3. Multiple sequence alignment of pvron2. Alignment of representative pvron2 sequ... more Additional file 3. Multiple sequence alignment of pvron2. Alignment of representative pvron2 sequences from Brazil and Peru, compared to the P. vivax Sal-1 strain (PlasmoDB PVX_117880). (A) Nucleotide sequences of region 5.482–6.240. (B) Amino acid sequences of region 1828–2080 aa. The alignment was made using VLC Sequence Viewer 7.
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Papers by Catarina Bourgard