Antileishmanial High-Throughput Drug Screening Reveals Drug Candidates with New Scaffolds

Siqueira-Neto, Jair L.,Song, Ok-Ryul,Oh, Hyunrim,Sohn, Jeong-Hun,Yang, Gyongseon,Nam, Jiyoun,Jang, Jiyeon,Cechetto, Jonathan,Lee, Chang Bok,Moon, Seunghyun,Genovesio, Auguste,Chatelain, Eric,Christoph Public Library of Science 2010 PLoS neglected tropical diseases Vol.4 No.5

<▼1><P>Drugs currently available for leishmaniasis treatment often show parasite resistance, highly toxic side effects and prohibitive costs commonly incompatible with patients from the tropical endemic countries. In this sense, there is an urgent need for new drugs as a treatment solution for this neglected disease. Here we show the development and implementation of an automated high-throughput viability screening assay for the discovery of new drugs against <I>Leishmania</I>. Assay validation was done with <I>Leishmania</I> promastigote forms, including the screening of 4,000 compounds with known pharmacological properties. In an attempt to find new compounds with leishmanicidal properties, 26,500 structurally diverse chemical compounds were screened. A cut-off of 70% growth inhibition in the primary screening led to the identification of 567 active compounds. Cellular toxicity and selectivity were responsible for the exclusion of 78% of the pre-selected compounds. The activity of the remaining 124 compounds was confirmed against the intramacrophagic amastigote form of the parasite. <I>In vitro</I> microsomal stability and cytochrome P450 (CYP) inhibition of the two most active compounds from this screening effort were assessed to obtain preliminary information on their metabolism in the host. The HTS approach employed here resulted in the discovery of two new antileishmanial compounds, bringing promising candidates to the leishmaniasis drug discovery pipeline.</P></▼1><▼2><P><B>Author Summary</B></P><P>Every year, more than 2 million people worldwide suffer from leishmaniasis, a neglected tropical disease present in 88 countries. The disease is caused by the single-celled protozoan parasite species of the genus <I>Leishmania</I>, which is transmitted to humans by the bite of the sandfly. The disease manifests itself in a broad range of symptoms, and its most virulent form, named visceral leishmaniasis, is lethal if not treated. Most of the few available treatments for leishmaniasis were developed decades ago and are often toxic, sometimes even leading to the patient's death. Furthermore, the parasite is developing resistance to available drugs, making the discovery and development of new antileishmanials an urgent need. To tackle this problem, the authors of this study employed the use of high-throughput technologies to screen a large library of small, synthetic molecules for their ability to interfere with the viability of <I>Leishmania</I> parasites. This study resulted in the discovery of two novel compounds with leishmanicidal properties and promising drug-like properties, bringing new candidates to the leishmaniasis drug discovery pipeline.</P></▼2>

An Image-Based High-Content Screening Assay for Compounds Targeting Intracellular <i>Leishmania donovani</i> Amastigotes in Human Macrophages

Siqueira-Neto, Jair L.,Moon, Seunghyun,Jang, Jiyeon,Yang, Gyongseon,Lee, Changbok,Moon, Hong Kee,Chatelain, Eric,Genovesio, Auguste,Cechetto, Jonathan,Freitas-Junior, Lucio H. Public Library of Science 2012 PLoS neglected tropical diseases Vol.6 No.6

<▼1><P>Leishmaniasis is a tropical disease threatening 350 million people from endemic regions. The available drugs for treatment are inadequate, with limitations such as serious side effects, parasite resistance or high cost. Driven by this need for new drugs, we developed a high-content, high-throughput image-based screening assay targeting the intracellular amastigote stage of different species of <I>Leishmania</I> in infected human macrophages. The <I>in vitro</I> infection protocol was adapted to a 384-well-plate format, enabling acquisition of a large amount of readouts by automated confocal microscopy. The reading method was based on DNA staining and required the development of a customized algorithm to analyze the images, which enabled the use of non-modified parasites. The automated analysis generated parameters used to quantify compound activity, including infection ratio as well as the number of intracellular amastigote parasites and yielded cytotoxicity information based on the number of host cells. Comparison of this assay with one that used the promastigote form to screen 26,500 compounds showed that 50% of the hits selected against the intracellular amastigote were not selected in the promastigote screening. These data corroborate the idea that the intracellular amastigote form of the parasite is the most appropriate to be used in primary screening assay for <I>Leishmania</I>.</P></▼1><▼2><P><B>Author Summary</B></P><P>Leishmaniasis, one of the most neglected tropical diseases, affects over 2 million people each year. Visceral leishmaniasis (VL), also known as Kala-azar, is caused by the protozoan parasites <I>Leishmania donovani</I> and <I>Leishmania infantum</I> and is fatal if left untreated. Because existing treatments are often ineffective due to parasite resistance and/or toxicity new drugs are urgently needed. Leishmaniasis is transmitted to humans by the bite of an infected sandfly. In the insect vector, parasites exist as flagellated forms—promastigotes, which infect macrophage cells of the human host, where they differentiate to round forms known as amastigotes. Amastigotes and promastigotes are substantially different from a molecular perspective. Drug discovery for leishmaniasis has traditionally been complicated by the unavailability of validated drug targets and of relevant drug assays. Whole cell-based assays have been widely used, as they bypass the need for a validated target. However, they use the insect form of the parasite; indeed, the human form, the intracellular amastigote, is difficult to obtain in the laboratory in quantities compatible with drug screening. We describe here the technical advances that made it possible to adapt the intracellular amastigote form of <I>L. donovani</I> to a drug assay compatible with high-throughput screening.</P></▼2>

Nonlinear System Identification of a Refrigeration System

Tarcísio Soares Siqueira Dantas,Ivan Carlos Franco,Ana Maria Frattini Fileti,Fl avio Vasconcelos da Silva 대한설비공학회 2016 International Journal Of Air-Conditioning and Refr Vol.24 No.4

Applications of advanced control algorithms are important in the refrigeration field to achieve low-energy costs and accurate set-point tracking. However, the designing and tuning of control systems depend on dynamic mathematical models. Approaches like analytical modeling can be time-consuming because they usually lead to a large number of differential equations with unknown parameters. In this work, the application of system identification with the fast recursive orthogonal least square (FROLS) algorithm is proposed as an alternative to analytical modeling to develop a process dynamic model. The evaporating temperature (EVT), condensing temperature (CDT) and useful superheat (USH) are the outputs of interest for this system; covariance analysis of the candidate inputs shows that the model should be single-input–single-output (SISO). Good simulation results are obtained with two different validation data, with average output errors of 0.0343 (EVT model), 0.0079 (CDT model) and 0.1578 (USH model) for one of the datasets, showing that this algorithm is a valid alternative for modeling refrigeration systems

Ultrathin Polymer Fibers Coated with an Amorphous SiO2–CaO–P2O5 Bioactive Powders for Biomedical Applications

Lilian de Siqueira,Verônica Ribeiro dos Santos,Juliani Caroline Ribeiro de Araújo,Hugo Gutemberg Patiño de Oliveira Filho,Luana Marotta Reis de Vasconcellos,Eliandra de Sousa Trichês,Alexandre Luiz So 한국섬유공학회 2023 Fibers and polymers Vol.24 No.9

The development of new biomaterials with improved properties is a trend in tissue regeneration. In this way, an innovative approach is employed in this work for obtaining polymer fibers coated with nanoparticles resulting from the simultaneous application of poly (lactic acid) (PLA)/polycaprolactone (PCL) electrospinning and bioactive particles from an amorphous multicomponent silica–calcium–phosphorus system (AMS) electrospraying. The osteogenesis was evaluated in vitro and in vivo using male rats, in which total protein, alkaline phosphatase, and biological performance through histological and histomorphometric analysis were discussed. The morphological results assessed by scanning electron microscopy showed a mesh of PLA/PCL fibers associated with AMS. The spraying of 17.44% of AMS particles in the PLA/PCL electrospun fibers decreased the Young’s modulus and tensile strength. However, the amount of AMS particles sprayed was enough to promote a reduction of 17.8% in the measured contact angle values. Phosphatase alkaline higher mean value was also observed in the fibers when in contact with the AMS, but nonstatistical difference was observed (p > 0.05). It was possible to observe the presence of mineralized nodules deposited on the bottom of the plate and between the fibers. The newly formed bone into defect filled with PLA/PCL-AMS fibers was higher than that observed in the control group. These findings suggest PLA/PCL-AMS fibers as a multifunctional composite system that may be attractive for both bone and dental tissue engineering applications.

치과수술 후 진통에 대한 디클로페낙 포타슘의 이중맹검 효력비교시험

J.T.T. de Siqueira,B.J.Potenza,D.Basta 임상약학사 1993 臨床藥學 Vol.13 No.4

An interfacial zone evolutionary optimization method with manufacturing constraints for hybrid components

Renan da Silva de Siqueira,Iryna Mozgova,Roland Lachmayer 한국CDE학회 2019 Journal of computational design and engineering Vol.6 No.3

New multi-material manufacturing technologies demand the development of new mechanical design approaches, as seen in the production of hybrid components through Tailored Forming. Thereby, a new class of high-performance multi-material parts aiming for enhanced properties, such as lightweight prop-erties, can be constructed and brings with it new challenges. The objective of this paper is to develop a method for finding the optimal material distribution for such multi-material components. Thereunto, Topology Optimization techniques were reviewed, focusing on the progress made on multi-materials and manufacturing constraints implementations. Following, a new method was developed and analyzed, called Interfacial Zone Evolutionary Optimization (IZEO), and here expanded for a multi-material approach. This method makes use of the Evolutionary Algorithms methodology to solve structural opti-mization problems and provides a flexible way to implement manufacturing constraints. Finally, some cases are presented, in which the developed tool was able to generate a multi-material and manufac-turable high-performance design.

Oral Administration of Aloe vera (L.) Burm. f. (Xanthorrhoeaceae) and Honey Improves the Host Body Composition and Modulates Proteolysis Through Reduction of Tumor Progression and Oxidative Stress in Rats

Rebeka Tomasin,Rafael Siqueira de Andrade,Maria Cristina Cintra Gomes-Marcondes 한국식품영양과학회 2015 Journal of medicinal food Vol.18 No.10

Oxidative stress has a dual role in cancer; it is linkedwith tumorigenic events and hostwasting, aswell as senescence and apoptosis. Researchers have demonstrated the importance of coadjuvant therapies in cancer treatment, and Aloe vera and honey have immunomodulatory, anticancer, and antioxidant properties. The preventive and therapeutic effects of Aloe vera (L.) Burm. f. (Xanthorrhoeaceae) and honey in tumor progression and host wasting were analyzed in Walker 256 carcinoma-bearing rats. The animalswere distributed into the following groups:C= control-untreated,W= tumor-untreated,WA= treated after tumor induction, A= control-treated, AW= treated before tumor induction, and AWA= treated before and after tumor induction. Proteolysis and oxidative stress were analyzed in the tumor, liver, muscle, and myocardial tissues. The results suggest that the Aloe vera and honey treatment affect the tumor and host by different mechanisms; the treatment-modulated host wasting and cachexia, whereas it promoted oxidative stress and damage in tumor tissues, particularly in a therapeutic context (WA).

High Content Screening Pipe Line for Leishmaniasis

Seunghyun Moon,Jair L. Siqueira-Neto,Lucio H. Freitas-Junoir,Auguste Genovesio,Myungjoo Kang 한국산업응용수학회 2009 한국산업응용수학회 학술대회 논문집 Vol.4 No.2

Cytocompatibility and cell proliferation evaluation of calcium phosphate-based root canal sealers

Letícia Boldrin Mestieri,Ivana Maria Zaccara,Lucas Siqueira Pinheiro,Fernando Branco Barletta,Patrícia Maria Polli Kopper,Fabiana Soares Grecca 대한치과보존학회 2020 Restorative Dentistry & Endodontics Vol.45 No.1

Objectives: This study aimed to evaluate the cell viability and migration of Endosequence Bioceramic Root Canal Sealer (BC Sealer) compared to MTA Fillapex and AH Plus. Materials and Methods: BC Sealer, MTA Fillapex, and AH Plus were placed in contact with culture medium to obtain sealers extracts in dilution 1:1, 1:2 and 1:4. 3T3 cells were plated and exposed to the extracts. Cell viability and migration were assessed by 3-(4,5-dimethyl-thiazoyl)-2,5-diphenyl-tetrazolium bromide (MTT) and Scratch assay, respectively. Data were analyzed by Kruskal-Wallis and Dunn's test (p < 0.05). Results: The MTT assay revealed greater cytotoxicity for AH Plus and MTA Fillapex at 1:1 dilution when compared to control (p < 0.05). At 1:2 and 1:4 dilutions, all sealers were similar to control (p > 0.05) and MTA Fillapex was more cytotoxic than BC Sealer (p < 0.05). Scratch assay demonstrated the continuous closure of the wound according to time. At 30 hours, the control group presented closure of the wound (p < 0.05). At 36 hours, only BC Sealer presented the closure when compared to AH Plus and MTA Fillapex (p < 0.05). At 42 hours, AH Plus and MTA Fillapex showed a wound healing (p > 0.05). Conclusions: All tested sealers demonstrated cell viability highlighting BC Sealer, which showed increased cell migration capacity suggesting that this sealer may achieve better tissue repair when compared to other tested sealers.

Impact of combined at-home bleaching and whitening toothpaste use on the surface and color of a composite resin

Barbosa Carolina Meneghin,Scatolin Renata Siqueira,Vieira-Junior Waldemir Francisco,Tanaka Marcia Hiromi,Ferraz Laura Nobre 대한치과보존학회 2023 Restorative Dentistry & Endodontics Vol.48 No.3

Objective This in vitro study aimed to evaluate the effects of different whitening toothpastes on a composite resin during at-home bleaching with 10% carbamide peroxide. Materials and Methods Sixty samples (7 mm × 2 mm) were used for color and roughness analyses, while another 60 samples (3 mm × 2 mm) were utilized to assess microhardness. The factors analyzed included toothpaste, for which 5 options with varying active agents were tested (distilled water; conventional toothpaste; whitening toothpaste with abrasive agents; whitening toothpaste with abrasive and chemical agents; and whitening toothpaste with abrasive, chemical, and bleaching agents). Brushing and application of whitening gel were performed for 14 days. Surface microhardness (SMH), surface roughness (Ra), and color (∆L*, ∆a*, ∆b, ∆E*ab, and ∆E00) were analyzed. The Ra and SMH data were analyzed using mixed generalized linear models for repeated measures, while the color results were assessed using the Kruskal-Wallis and Dunn tests. Results Between the initial and final time points, all groups demonstrated significant increases in Ra and reductions in SMH. No significant differences were found between groups for SMH at the final time point, at which all groups differed from the distilled water group. Conventional toothpaste exhibited the lowest Ra, while whitening toothpaste with abrasive agent had the highest value. No significant differences were observed in ∆L*, ∆a*, and ∆b. Conclusions While toothpaste composition did not affect the color stability and microhardness of resin composite, combining toothbrushing with whitening toothpaste and at-home bleaching enhanced the change in Ra. Objective This in vitro study aimed to evaluate the effects of different whitening toothpastes on a composite resin during at-home bleaching with 10% carbamide peroxide. Materials and Methods Sixty samples (7 mm × 2 mm) were used for color and roughness analyses, while another 60 samples (3 mm × 2 mm) were utilized to assess microhardness. The factors analyzed included toothpaste, for which 5 options with varying active agents were tested (distilled water; conventional toothpaste; whitening toothpaste with abrasive agents; whitening toothpaste with abrasive and chemical agents; and whitening toothpaste with abrasive, chemical, and bleaching agents). Brushing and application of whitening gel were performed for 14 days. Surface microhardness (SMH), surface roughness (Ra), and color (∆L*, ∆a*, ∆b, ∆E*ab, and ∆E00) were analyzed. The Ra and SMH data were analyzed using mixed generalized linear models for repeated measures, while the color results were assessed using the Kruskal-Wallis and Dunn tests. Results Between the initial and final time points, all groups demonstrated significant increases in Ra and reductions in SMH. No significant differences were found between groups for SMH at the final time point, at which all groups differed from the distilled water group. Conventional toothpaste exhibited the lowest Ra, while whitening toothpaste with abrasive agent had the highest value. No significant differences were observed in ∆L*, ∆a*, and ∆b. Conclusions While toothpaste composition did not affect the color stability and microhardness of resin composite, combining toothbrushing with whitening toothpaste and at-home bleaching enhanced the change in Ra.