Glycosylated metal chelators as anti-parasitic agents with tunable selectivity

Trypanosoma cruzi and Leishmania amazonensis are the causative agents of Chagas’ disease and leishmaniasis, respectively. These conditions affect millions of people worldwide, especially in developing countries. As such, there is an urgent need for novel, efficient and cost-effective treatments for these diseases, given the growing resistance and side-effects of current therapies. This work details the synthesis and evaluation of the anti-parasitic activity of novel amino- and iminopyridyl metal chelators, their glycosylated derivatives and some of their metal complexes. Our results revealed the potent and metal-dependent activity for the aminopyridyl compounds: Cu(II) complexes were most effective against T. cruzi trypomastigotes, while Zn(II) complexes presented excellent activity against L. amazonensis promastigotes. In addition, the compounds showed excellent selectivity indexes and very low relative toxicity as judged by in vitro and in vivo studies, respectively, using RAW macrophages and Galleria mellonella larvae model

Naringenin-functionalized multi-walled carbon nanotubes: a potential approach for site-specific remote-controlled anticancer delivery for the treatment of lung cancer cells

Multi-walled carbon nanotubes functionalized with naringenin have been developed as new drug carriers to improve the performance of lung cancer treatment. The nanocarrier was characterized by Transmission Electron Microscopy (TEM), Fourier-Transform Infrared Spectroscopy (FTIR), X-ray photoelectron spectroscopy, Raman Spectroscopy, and Differential Scanning Calorimetry (DSC). Drug release rates were determined in vitro by the dialysis method. The cytotoxic profile was evaluated using the MTT assay, against a human skin cell line (hFB) as a model for normal cells, and against an adenocarcinomic human alveolar basal epithelial (A569) cell line as a lung cancer in vitro model. The results demonstrated that the functionalization of carbon nanotubes with naringenin occurred by non-covalent interactions. The release profiles demonstrated a pH-responsive behavior, showing a prolonged release in the tumor pH environment. The naringenin-functionalized carbon nanotubes showed lower cytotoxicity on non-malignant cells (hFB) than free naringenin, with an improved anticancer effect on malignant lung cells (A549) as an in vitro model of lung cancer.This work was supported by the Banco do Nordeste (grant FUNDECI/2016.0015), Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq), Fundação de Apoio à Pesquisa e à Inovação Tecnológica do Estado de Sergipe (Fapitec) and Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES). Eliana B. Souto would like to acknowledge the contributions from the Portuguese Science and Technology Foundation (FCT/MCT) and from European Funds (PRODER/COMPETE) for the projects M-ERA-NET/0004/2015-PAIRED and UIDB/04469/2020 (strategic fund), co-financed by FEDER, under the Partnership Agreement PT2020.info:eu-repo/semantics/publishedVersio

Cashew gum (Anacardium occidentale) as a potential source for the production of tocopherol-loaded nanoparticles: formulation, release profile and cytotoxicity

Every year, more than thirty thousand tons of Cashew gum (Anacardium occidentale, family: Anacardiaceae) are produced in Brazil; however, only a small amount is used for different applications in foodstuff and in pharmaceutical industries. As a raw material for the production of drug delivery systems, cashew gum is still regarded as an innovative compound worth to be exploited. In this work, cashew gum was extracted from the crude exudate of cashew tree employing four methodologies resulting in a light brown powder in different yields (40.61% to 58.40%). The total ashes (0.34% to 1.05%) and moisture (12.90% to 14.81%) were also dependent on the purification approach. FTIR spectra showed the typical bands of purified cashew gum samples, confirming their suitability for the development of a pharmaceutical product. Cashew gum nanoparticles were produced by nanoprecipitation resulting in particles of low polydispersity (<0.2) and an average size depending on the percentage of the oil. The zeta potential of nanoparticles was found to be below 20 mV, which promotes electrostatic stability. Encapsulation efficiencies were above 99.9%, while loading capacity increased with the increase of the percentage of the oil content of particles. The release of the oil from the nanoparticles followed the KorsmeyerPeppas kinetics model, while particles did not show any signs of toxicity when tested in three distinct cell lines (LLC-MK2, HepG2, and THP-1). Our study highlights the potential added value of using a protein-, lignans-, and nucleic acids-enriched resin obtained from crude extract as a new raw material for the production of drug delivery systems.This research received funding from the Coordenação Aperfeiçoamento de Pessoal de Nivel Superior (CAPES), Fundação de Ámparo à Pesquisa do Estado de Sergipe (FAPITEC) (PROCESSO: 88887.159533/2017-00 extração, encapsulação e caracterização de bioativos para o interesse biotecnologico) and Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq 301964/2019-0 Chamada 06/2019, and Chamada CNPq nº 01/2019), from Portuguese Foundation for Science and Technology (FCT/MEC) through national funds, and co-financed by FEDER, under the Partnership Agreement PT2020 for the project UIDB/04469/2020.info:eu-repo/semantics/publishedVersio

MDL28170, a Calpain Inhibitor, Affects Trypanosoma cruzi Metacyclogenesis, Ultrastructure and Attachment to Rhodnius prolixus Midgut

BACKGROUND: Trypanosoma cruzi is the etiological agent of Chagas' disease. During the parasite life cycle, many molecules are involved in the differentiation process and infectivity. Peptidases are relevant for crucial steps of T. cruzi life cycle; as such, it is conceivable that they may participate in the metacyclogenesis and interaction with the invertebrate host. METHODOLOGY/PRINCIPAL FINDINGS: In this paper, we have investigated the effect of the calpain inhibitor MDL28170 on the attachment of T. cruzi epimastigotes to the luminal midgut surface of Rhodnius prolixus, as well as on the metacyclogenesis process and ultrastructure. MDL28170 treatment was capable of significantly reducing the number of bound epimastigotes to the luminal surface midgut of the insect. Once the cross-reactivity of the anti-Dm-calpain was assessed, it was possible to block calpain molecules by the antibody, leading to a significant reduction in the capacity of adhesion to the insect guts by T. cruzi. However, the antibodies were unable to interfere in metacyclogenesis, which was impaired by the calpain inhibitor presenting a significant reduction in the number of metacyclic trypomastigotes. The calpain inhibitor also promoted a direct effect against bloodstream trypomastigotes. Ultrastructural analysis of epimastigotes treated with the calpain inhibitor revealed disorganization in the reservosomes, Golgi and plasma membrane disruption. CONCLUSIONS/SIGNIFICANCE: The presence of calpain and calpain-like molecules in a wide range of organisms suggests that these proteins could be necessary for basic cellular functions. Herein, we demonstrated the effects of MDL28170 in crucial steps of the T. cruzi life cycle, such as attachment to the insect midgut and metacyclogenesis, as well as in parasite viability and morphology. Together with our previous findings, these results help to shed some light on the functions of T. cruzi calpains. Considering the potential roles of these molecules on the interaction with both invertebrate and vertebrate hosts, it is interesting to improve knowledge on these molecules in T. cruzi

Funding for Chagas Disease: A 10-Year (2009–2018) Survey

Chagas disease was discovered in 1909 by the Brazilian scientist Carlos Chagas. After more than 110 years, many outcomes have been achieved in all research fields; however, Chagas disease remains a serious public health problem, mainly in Latin America, being one of the most neglected tropical diseases in the world. As a neglected disease, it receives very little financial support. Nevertheless, how much is actually spent? With this question in mind, the goal of the present work was to summarize all funding employed by multiple institutions in the Chagas disease field in a 10-year survey. From 2009 to 2018, Chagas disease received only USD 236.31 million, representing 0.67% of the total applied for all neglected diseases in this period. Mostly, the investments are concentrated in basic research (47%) and drug development (42.5%), with the public sector responsible for 74% of all funding, followed by the industry (19%) and philanthropy (7%). Relevantly, NIH (USA) alone accounted for more than half of the total investment. Taking into account that Chagas disease has a great socio-economic impact, it is clear that more investments are needed, especially from endemic countries. Furthermore, coordinated strategies to make better use of resources and incentives for the pharmaceutical industry must be adopted

US Public Attitudes Toward COVID-19 Vaccine Mandates

Ending the coronavirus disease 2019 (COVID-19) pandemic through vaccination will require sufficient uptake, possibly through mandatory vaccination. At present, certain vaccines are required for children to attend school. Although vaccine mandates for adults are legal, they have generally been applied narrowly to select groups, such as health care workers, rather than broadly enforced. We surveyed the US public to assess acceptability of COVID-19 vaccine mandates

Public Perspectives on COVID-19 Vaccine Prioritization

Importance: As COVID-19 vaccine distribution continues, policy makers are struggling to decide which groups should be prioritized for vaccination. Objective: To assess US adults\u27 preferences regarding COVID-19 vaccine prioritization. Design, Setting, and Participants: This survey study involved 2 independent, online surveys of US adults aged 18 years and older, 1 conducted by Gallup from September 14 to 27, 2020, and the other conducted by the COVID Collaborative from September 19 to 25, 2020. Samples were weighted to reflect sociodemographic characteristics of the US population. Exposures: Respondents were asked to prioritize groups for COVID-19 vaccine and to rank their prioritization considerations. Main Outcomes and Measures: The study assessed prioritization preferences and agreement with the National Academies of Science, Engineering, and Medicine\u27s Preliminary Framework for Equitable Allocation of COVID-19 Vaccine. Results: A total of 4735 individuals participated, 2730 (1474 men [54.1%]; mean [SD] age, 59.2 [14.5] years) in the Gallup survey and 2005 (944 men [47.1%]; 203 participants [21.5%] aged 55-59 years) in the COVID Collaborative survey. In both the Gallup COVID-19 Panel and COVID Collaborative surveys, respondents listed health care workers (Gallup, 93.6% [95% CI, 91.2%-95.3%]; COVID Collaborative, 80.0% [95% CI, 78.0%-81.9%]) and adults of any age with serious comorbid conditions (Gallup, 78.6% [95% CI, 75.2%-81.7%]; COVID Collaborative, 72.9% [95% CI, 70.7%-74.9%]) among their 4 highest priority groups. Respondents of all political affiliations agreed with prioritizing Black, Hispanic, Native American, and other communities that have been disproportionately affected by COVID-19 (Gallup, 74.2% [95% CI, 70.6%-77.5%]; COVID Collaborative, 84.9% [95% CI, 83.1%-86.5%]), and COVID Collaborative respondents were willing to be preceded in line by teachers and childcare workers (92.5%; 95% CI, 91.2%-93.7%) and grocery workers (85.9%; 95% CI, 84.2%-87.5%). Older respondents in both surveys were significantly less likely than younger respondents to prioritize healthy adults aged 65 years and older among their 4 highest priority groups (Gallup, 23.7% vs 39.1% [χ2= 2160.8; P \u3c001]; COVID Collaborative, 23.3% vs 28.8% [χ2= 5.0198; P =.03]). COVID Collaborative respondents believed the 4 most important considerations for prioritization were preventing COVID-19 spread (78.4% [95% CI, 76.3%-80.3%]), preventing the most deaths (72.1% [95% CI, 69.9%-74.2%]), preventing long-term complications (68.9% [66.6%-71.9%]), and protecting frontline workers (63.8% [95% CI, 61.5%-66.1%]). Conclusions and Relevance: US adults broadly agreed with the National Academies of Science, Engineering, and Medicine\u27s prioritization framework. Respondents endorsed prioritizing racial/ethnic communities that are disproportionately affected by COVID-19, and older respondents were significantly less likely than younger respondents to endorse prioritizing healthy people older than 65 years. This provides reason for caution about COVID-19 vaccine distribution plans that prioritize healthy adults older than a cutoff age without including those younger than that age with preexisting conditions, that aim solely to prevent the most deaths, or that give no priority to frontline workers or disproportionately affected communities

Lopinavir and Nelfinavir Induce the Accumulation of Crystalloid Lipid Inclusions within the Reservosomes of Trypanosoma cruzi and Inhibit Both Aspartyl-Type Peptidase and Cruzipain Activities Detected in These Crucial Organelles

Several research groups have explored the repositioning of human immunodeficiency virus aspartyl peptidase inhibitors (HIV-PIs) on opportunistic infections caused by bacteria, fungi and protozoa. In Trypanosoma cruzi, HIV-PIs have a high impact on parasite viability, and one of the main alterations promoted by this treatment is the imbalance in the parasite’s lipid metabolism. However, the reasons behind this phenomenon are unknown. In the present work, we observed by transmission electron microscopy (TEM) that the treatment of T. cruzi epimastigotes with the HIV-PIs lopinavir and nelfinavir induced a huge accumulation of crystalloid-shaped lipids within the reservosomes, most of them deforming these key organelles. As previously reported, those structures are characteristic of lipid inclusions formed mostly of cholesterol and cholesterol-esters. The fractionation of nontreated epimastigotes generated two distinct fractions enriched in reservosomes: one mostly composed of lipid inclusion-containing reservosomes (Fraction B1) and one where lipid inclusions were much less abundant (Fraction B2). Interestingly, the extract of Fraction B2 presented enzymatic activity related to aspartyl-type peptidases 3.5 times higher than that found in the extract obtained from Fraction B1. The cleavage of cathepsin D substrate by this class of peptidases was strongly impaired by pepstatin A, a prototypical aspartyl PI, and the HIV-PIs lopinavir and nelfinavir. In addition, both HIV-PIs also inhibited (to a lesser extent) the cruzipain activity present in reservosomes. Finally, our work provides new evidence concerning the presence and supposed participation of aspartyl peptidases in T. cruzi, even as it adds new information about the mechanisms behind the alterations promoted by lopinavir and nelfinavir in the protozoan