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Schistosomiasis is one of the major parasitic diseases with more than 200 million people infected worldwide every year. Praziquantel is the drug of choice against the schistosomiasis although the use of a single drug to treat such a large amount of infected people appears particularly worrisome. For this reason, the search of new schistosomicidal compounds is viewed as an urgent goal and a number of screening campaigns have been carried out in the past years. The larval stage of Schistosoma (schistosomula) has been widely used in order to identify new compounds against the parasite. Here we describe detailed practical procedures for a luminescence-based assay proven to be highly effective for the selection of schistosomicidal compounds on small and medium-high scale. The assay is based on the quantitation of the parasite ATP, a good indicator of metabolically active cells, as measure of schistosomula viability. This assay is fast and reproducible, and it is suitable either for manual or for semiautomated screenings.

Background. Cardiac stem cells expressing the tyrosine kinase receptor c-kit have been recently used in in vivo and in vitro cardiac regenerative studies. However, it remains to be clarified whether the c-kit receptor itself plays a critical role in the process of cardiac regeneration. In order to clarify this point, we will explore whether c-Kit receptor affects cardiac stem cells proliferation, survival, migration and differentiation after heart injury. Methods and Results. We have generated transgenic mice in which an activatory point mutation (c-KitD814Y mice) has been introduced in the kinase domain of the c-kit gene. Initially, we have analyzed c-kit expression in tissues and organs at different stages of embryonal and post-natal development through immunohystochemical and biochemical analyses. We have found that in two transgenic lines the receptor is highly expressed and activated in heart, testis and cerebellum, compared to wild type mice. In order to follow the fate of the c-Kit transgenic stem cells we crossed c-KitD814Y mice with mice expressing GFP under c-Kit regulative sequences control. By cytofluorimetric and fluorescence microscopy analyses, we observed a 2 fold of increase in the number of c-kit positive cells on heart samples from double transgenic mice at different ages. To verify the c-kit role in cardiac regeneration we performed a necrotic heart damage in vivo and monitored cardiac repair in transgenic mice versus wild-type mice. After 9 days the wounded hearts of transgenic mice presented a larger connectival tissue area compared to wild-type mice. On the contrary, after 45 days a consistent reduction of fibrotic area was observed in transgenic mice. These preliminary results suggest a faster repair of damaged heart area that contain stem cells with an activated c-kit receptor. Further in vitro and in vivo experiments will be performed to assess whether transgenic c-kit cells directly transdifferentiate into cardiomyocytes or whether they act in a paracrine manner. In summary, the generation of transgenic mice carrying a constitutively activated c-kit in cardiac stem cells, will allow to investigate the role of the receptor and to highlight the molecular mechanism underlying heart regeneration., Italian Journal of Anatomy and Embryology, Vol 117, No 2 (Supplement) 2012

Schistosomiasis is a neglected tropical disease mainly affecting the poorest tropical and subtropical areas of the world with the impressive number of roughly 200 million infections per year. Schistosomes are blood trematode flukes of the genus Schistosoma causing symptoms in humans and animals. Organ morbidity is caused by the accumulation of parasite eggs and subsequent development of fibrosis. If left untreated, schistosomiasis can result in substantial morbidity and even mortality. Praziquantel (PZQ) is the most effective and widely used compound for the treatment of the disease, in prevention and control programs in the last 30 years. Unfortunately, it has no effect on juvenile immature schistosomes and cannot prevent reinfection or interfere with the schistosome life cycle; moreover drug-resistance represents a serious threat. The search for an alternative or complementary treatment is urgent and drug repurposing could accelerate a solution. The anti-anginal drug perhexiline maleate (PHX) has been previously shown to be effective on larval, juvenile, and adult stages of S. mansoni and to impact egg production in vitro. Since PHX is a racemic mixture of R-(+)- and S-(−)-enantiomers, we designed and realized a stereoselective synthesis of both PHX enantiomers and developed an analytical procedure for the direct quantification of the enantiomeric excess also suitable for semipreparative separation of PHX enantiomers. We next investigated the impact of each enantiomer on viability of newly transformed schistosomula (NTS) and worm pairs of S. mansoni as well as on egg production and vitellarium morphology by in vitro studies. Our results indicate that the R-(+)-PHX is mainly driving the anti-schistosomal activity but that also the S-(−)-PHX possesses a significant activity towards S. mansoni in vitro.

Neglected tropical diseases (NTDs), caused by several parasitic agents (Plasmodium spp., Schistosoma spp., Leishmania spp.), are still characterized by a high morbidity percentage worldwide. The therapeutic alternatives for neglected pathologies are very limited, first due to the drug-resistance phenomena but also due to unfavourable toxicity profiles and the difficult administration procedures of the few available chemical entities. A further drawback is represented by multiparasitism, namely the concurrent infestation of a single host by more than one parasite species, which poses additional diagnostic and therapeutic challenges [1]. In this view, a research aimed to discover a new chemical entity active against several parasites is crucial and the marine environment may be important resource [2]. As part of our own continuing search for new leads in the treatment of NTDs [3–5] we have explored the anti infective properties of the sponge derived metabolites avarone and avarol, as well as those of the semisynthetic thiazoavarone, obtained by converting the quinone avarone in the relevant thiazinoquinone. All compounds were shown to be active against the D10 and W2 strains of P. falciparum, the juvenile and adult forms of the worm S. mansoni, and both the promastigote and amastigote stages of L. infantum and L. tropica.

WOS: 000518664600043 PubMed ID: 32075136 The chemical analysis of the sponge Dysidea avara afforded the known sesquiterpene quinone avarone, along with its reduced form avarol. To further explore the role of the thiazinoquinone scaffold as an antiplasmodial, antileishmanial and antischistosomal agent, we converted the quinone avarone into the thiazinoquinone derivative thiazoavarone. The semisynthetic compound, as well as the natural metabolites avarone and avarol, were pharmacologically investigated in order to assess their antiparasitic properties against sexual and asexual stages of Plasmodium falciparum, larval and adult developmental stages of Schistosomamansoni (eggs included), and also against promastigotes and amastigotes of Leishmania infantum and Leishmania tropica. Furthermore, in depth computational studies including density functional theory (DFT) calculations were performed. A toxic semiquinone radical species which can be produced starting both from quinone- and hydroquinone-based compounds could mediate the anti-parasitic effects of the tested compounds. Ministero dell'Istruzione, dell'Universita e della Ricerca (MIUR), PRIN Projects [2010C2LKKJ_006, 20154JRJPP_004]; Regione Campania-POR Campania FESR 2014/2020 "Combattere la resistenza tumorale: piattaforma integrata multidisciplinare per un approccio tecnologico innovativo alle oncoterapie-Campania Oncoterapie" [B61G18000470007]; CNR (National Research Council)-CNCCS (Collezione Nazionale di Composti Chimici e Centro di screening) "Rare, Neglected and Poverty Related Diseases -Schistodiscovery Project" [DSB.AD011.001.003] This research was supported by Ministero dell'Istruzione, dell'Universita e della Ricerca (MIUR), PRIN Projects 2010C2LKKJ_006; 20154JRJPP_004, by a grant from Regione Campania-POR Campania FESR 2014/2020 "Combattere la resistenza tumorale: piattaforma integrata multidisciplinare per un approccio tecnologico innovativo alle oncoterapie-Campania Oncoterapie" (Project N. B61G18000470007) and by the CNR (National Research Council)-CNCCS (Collezione Nazionale di Composti Chimici e Centro di screening) "Rare, Neglected and Poverty Related Diseases -Schistodiscovery Project" (DSB.AD011.001.003).

A deep study of the metabolic content of the tunicate Polycarpa aurata, collected from Indonesian coast, afforded the isolation of two novel alkaloids, polyaurines A (1) and B (2), along with two new p-substituted benzoyl derivatives (3 and 4) and four known compounds (5&ndash, 8). The structural elucidation of the new secondary metabolites was assigned by 1D, 2D NMR, and HRESIMS techniques. Computational studies resulted a useful tool to unambiguously determine in polyaurine B the presence of rarely found 1,2,4-thiadiazole ring. The effects of polyaurines A and B on mammalian cells growth and on the viability of different blood-dwelling Schistosoma mansoni (phylum: Platyhelminthes) stages, as well as egg production, were evaluated. Both compounds resulted not cytotoxic, interestingly some of the eggs produced by polyaurine A-treated adult pairs in vitro are smaller, deformed, and/or fragmented, therefore, polyaurine A could represent an interesting bioactive natural molecule to be further investigated.