Androgens Exert a Cysticidal Effect upon Taenia crassiceps by Disrupting Flame Cell Morphology and Function

Sexual dimorphism in the murine model of extraparenchymal neurocysticercosis

Neurocysticercosis is a heterogeneous disease, and the patient's sex seems to play a role in this heterogeneity. Hosts' sexual dimorphism in cysticercosis has been largely explored in the murine model of intraperitoneal Taenia crassiceps cysticercosis. In this study, we investigated the sexual dimorphism of inflammatory responses in a rat model of extraparenchymal neurocysticercosis caused by T. crassiceps. T. crassiceps cysticerci were inoculated in the subarachnoid space of Wistar rats (25 females, 22 males). Ninety days later, the rats were euthanized for histologic, immunohistochemistry, and cytokines studies. Ten animals also underwent a 7-T magnetic resonance imaging (MRI). Female rats presented a higher concentration of immune cells in the arachnoid-brain interface, reactive astrogliosis in the periventricular region, in situ pro-inflammatory cytokine (interleukin [IL]-6) and anti-inflammatory cytokine (IL-10), and more intense hydrocephalus on MRI than males. Intracranial hypertension signals were not observed during the observational period. Overall, these results suggest sexual dimorphism in the intracranial inflammatory response that accompanied T. crassiceps extraparenchymal neurocysticercosis.

What about the Cytoskeletal and Related Proteins of Tapeworms in the Host's Immune Response? An Integrative Overview

Recent advances have increased our understanding of the molecular machinery in the cytoskeleton of mammalian cells, in contrast to the case of tapeworm parasites, where cytoskeleton remains poorly characterized. The pertinence of a better knowledge of the tapeworm cytoskeleton is linked to the medical importance of these parasitic diseases in humans and animal stock. Moreover, its study could offer new possibilities for the development of more effective anti-parasitic drugs, as well as better strategies for their surveillance, prevention, and control. In the present review, we compile the results of recent experiments on the cytoskeleton of these parasites and analyze how these novel findings might trigger the development of new drugs or the redesign of those currently used in addition to supporting their use as biomarkers in cutting-edge diagnostic tests.

Sex—the most underappreciated variable in research: insights from helminth-infected hosts

The sex of a host affects the intensity, prevalence, and severity of helminth infection. In many cases, one sex has been found to be more susceptible than the other, with the prevalence and intensity of helminth infections being generally higher among male than female hosts; however, many exceptions exist. This observed sex bias in parasitism results primarily from ecological, behavioural, and physiological differences between males and females. Complex interactions between these influences modulate the risk of infection. Indeed, an interplay among sex hormones, sex chromosomes, the microbiome and the immune system significantly contributes to the generation of sex bias among helminth-infected hosts. However, sex hormones not only can modulate the course of infection but also can be exploited by the parasites, and helminths appear to have developed molecules and pathways for this purpose. Furthermore, host sex may influence the efficacy of anti-helminth vaccines; however, although little data exist regarding this sex-dependent efficacy, host sex is known to influence the response to vaccines. Despite its importance, host sex is frequently overlooked in parasitological studies. This review focuses on the key contributors to sex bias in the case of helminth infection. The precise nature of the mechanisms/factors determining these sex-specific differences generally remains largely unknown, and this represents an obstacle in the development of control methods. There is an urgent need to identify any protective elements that could be targeted in future therapies to provide optimal disease management with regard to host sex. Hence, more research is needed into the impact of host sex on immunity and protection.

Annexin in Taenia crassiceps ORF Strain is Localized in the Osmoregulatory System

PURPOSE

Annexins are proteins with important roles in parasites, some of which are related to excretion-secretion processes, protein traffic, and microvesicle functionality. The participation of annexins in osmoregulation has been reported in tapeworms, including Taenia solium. This study aimed to investigate the localization and expression of annexin in cysticerci of Taenia crassiceps, used as a model of cysticercosis.

METHODS

We used an antibody made with a protein, previously employed on Schistosoma bovis, to detect annexin in T. crassiceps proteins extracts used Western blot assay. The histological distribution of annexin was studied with immunofluorescence and confocal microscopy.

RESULTS

The antibody against annexin recognized a band at a molecular weight of 40.9 kDa. The histological distribution of annexin showed that the protein is mainly localized in the tegument and the protonephridia ducts.

CONCLUSION

In our study, annexin was detected at a molecular weight similar to that described for Schistosoma bovis. In addition, its principal localization entailed structures of the osmoregulatory system one of the most important by the survival of the parasites. This confirms and solidifies previous reports concerning the role of annexins in T. crassiceps and this will be interesting by the development of new compounds against this protein.

Cysticidal effect of a pure naphthoquinone on Taenia crassiceps cysticerci

Cysticercosis is a disease caused by the metacestode of the parasite Taenia solium (T. solium). In humans, the most severe complication of the disease is neurocysticercosis. The drug of choice to treat this disease is albendazole; however, the bioavailability and efficacy of the drug are variable. Therefore, new molecules with therapeutic effects against this and other parasitic infections caused by helminths must be developed. Naphthoquinones are naphthalene-derived compounds that possess antibacterial, antifungal, antitumoral, and antiparasitic properties. The aim of this work was to evaluate the in vitro anti-helminthic effect of 2-[(3-chlorophenylamino)phenylmethyl]-3-hydroxy-1,4-naphthoquinone, isolated from a natural source and then synthesized (naphthoquinone 4a), using an experimental model of murine cysticercosis caused by Taenia crassiceps (T. crassiceps). This compound causes paralysis in the cysticerci membrane from day 3 of the in vitro treatment. Additionally, it induces changes in the shape, size, and appearance of the cysticerci and a decrease in the reproduction rate. In conclusion, naphthoquinone 4a has in vitro cysticidal activity on T. crassiceps cysticerci depending on the duration of the treatment and the concentration of the compound. Therefore, it is a promising drug candidate to be used in T. crassiceps and possibly T. solium infections.

Echinococcus granulosus: Insights into the protoscolex F-actin cytoskeleton

Echinococcus granulosus is a cestode parasite whose cytoskeleton plasticity allows it to enter and develop inside its hosts, completing thus its life cycle. We focused our attention on F-actin organization and distribution in E. granulosus protoscoleces (PSC) in order to contribute to the knowledge of the parasite cytoskeleton. In particular, we addressed some aspects of F-actin rearrangements in PSC at different stages of the evagination/invagination process. The use of light microscopy allowed us to identify different PSC structures and phalloidin staining displayed a parasite's highly organized F-actin cytoskeleton. Suckers exhibit an important musculature composed of a set of radial fibers. At the rostellum, the F-actin filaments are arranged in a bulbar shape with perforations that appear to be the attachment places for the hooks. Also, "circular" structures of F-actin were identified, which remind the flame cells. Furthermore, parasite F-actin filaments, unevenly distributed, seem to have remained substantially unchanged during the evagination/invagination process. Finally, we showed that the scolex of an evaginated E. granulosus PSC reinvaginates in vitro without any treatment.

In Vitro Analyses Reveal the Effect of Synthetic Cytokinin Forchlorfenuron (FCF) on a Septin-Like Protein of Taeniid Cysticerci

Cytokinin forchlorfenuron (FCF), a synthetic cytokinin, has been used specifically for the characterization of septins. In spite of genomic evidence of their existence, nothing is known about septin filaments in taeniid cestodes. The aim of this work was to determine the presence of a septin-like protein in cysticerci of Taenia crassiceps and Taenia solium using the deduced amino acid sequence of T. solium septin 4 (SEPT4_Tsm), to design and synthesize a derived immunogenic peptide (residues 88 to 103), to prepare a specific rabbit polyclonal antibody, and to examine the effects of FCF at different concentrations and exposure times on an in vitro culture of T. crassiceps cysticerci. In vitro, FCF altered the morphology and motility of T. crassiceps cysticerci, and its effects were reversible under specific concentrations. In addition, we observed by ultrastructural observation that FCF alters the cellular subunit of the protonephridial system of cestodes, where disruption of the axoneme pattern of flame cells was observed. The rabbit polyclonal antibody prepared against the synthetic peptide recognized a major band of 41 kDa in both parasites. Our results establish the importance of SEPT4_Tsm in the dynamics and survival of taeniid cysticerci, as well as their susceptibility to FCF. This is also the first report that a septin is present in the cytoskeleton of taeniids.

Proteomic profile associated with cell death induced by androgens in Taenia crassiceps cysticerci: proposed interactome

Androgens have been shown to exert a cysticidal effect uponTaenia crassiceps, an experimental model of cysticercosis. To further inquire into this matter, theTaenia crassicepsmodel was used to evaluate the expression of several proteins after testosterone (T4) and dihydrotestosterone (DHT)in vitrotreatment. Under 2-D proteomic maps, parasite extracts were resolved into approximately 130 proteins distributed in a molecular weight range of 10–250 kDa and isoelectrical point range of 3–10. The resultant proteomic pattern was analysed, and significant changes were observed in response to T4 and DHT. Based on our experience with electrophoretic patterns and proteomic maps of cytoskeletal proteins, alteration in the expression of isoforms of actin, tubulin and paramyosin and of other proteins was assessed. Considering that androgens may exert their biological activity in taeniids through the non-specific progesterone receptor membrane component (PGRMC), we harnessed bioinformatics to propose the identity of androgen-regulated proteins and establish their hypothetical physiological role in the parasites. These analyses yield a possible explanation of how androgens exert their cysticidal effects through changes in the expression of proteins involved in cytoskeletal rearrangement, dynamic vesicular traffic and transduction of intracellular signals.

A novel progesterone receptor membrane component (PGRMC) in the human and swine parasite Taenia solium: implications to the host-parasite relationship

Background

We have previously reported that progesterone (P₄) has a direct in vitro effect on the scolex evagination and growth of Taenia solium cysticerci. Here, we explored the hypothesis that the P₄ direct effect on T. solium might be mediated by a novel steroid-binding parasite protein.

Methods

By way of using immunofluorescent confocal microscopy, flow cytometry analysis, double-dimension electrophoresis analysis, and sequencing the corresponding protein spot, we detected a novel PGRMC in T. solium. Molecular modeling studies accompanied by computer docking using the sequenced protein, together with phylogenetic analysis and sequence alignment clearly demonstrated that T. solium PGRMC is from parasite origin.

Results

Our results show that P₄ in vitro increases parasite evagination and scolex size. Using immunofluorescent confocal microscopy, we detected that parasite cells showed expression of a P₄-binding like protein exclusively located at the cysticercus subtegumental tissue. Presence of the P₄-binding protein in cyst cells was also confirmed by flow cytometry. Double-dimension electrophoresis analysis, followed by sequencing the corresponding protein spot, revealed a protein that was previously reported in the T. solium genome belonging to a membrane-associated progesterone receptor component (PGRMC). Molecular modeling studies accompanied by computer docking using the sequenced protein showed that PGRMC is potentially able to bind steroid hormones such as progesterone, estradiol, testosterone and dihydrodrotestosterone with different affinities. Phylogenetic analysis and sequence alignment clearly demonstrated that T. solium PGRMC is related to a steroid-binding protein of Echinoccocus granulosus, both of them being nested within a cluster including similar proteins present in platyhelminths such as Schistocephalus solidus and Schistosoma haematobium.

Conclusion

Progesterone may directly act upon T. solium cysticerci probably by binding to PGRMC. This research has implications in the field of host-parasite co-evolution as well as the sex-associated susceptibility to this infection. In a more practical matter, present results may contribute to the molecular design of new drugs with anti-parasite actions.

Electronic supplementary material

The online version of this article (10.1186/s13071-018-2703-1) contains supplementary material, which is available to authorized users.

Dihydrotestosterone enhances growth and infectivity of Leishmania Mexicana

A strong sex-associated susceptibility towards Leishmania has been reported in males, yet little is known on the effect of hormones in Leishmania physiopathogenicity. Due to the enhanced susceptibility of males to Leishmania mexicana infections, we were interested in analysing the effect exerted by the main androgen produced in males (DHT) on L. mexicana promastigotes. Thus, the aim of this study was to assess the regulation exerted by dihydrotestosterone (DHT) on L. mexicana replication, infectivity, survival and development of tissue lesions. Experiments included growth curves of L. mexicana promastigotes incubated with different doses of DHT, their infection rate, intracellular survival and lesion development in BALB/c mice. Our data show that DHT significantly enhances parasite replication, infection rate and survival in bone marrow-derived macrophages (BMMФ). Promastigotes in the presence of DHT produced significantly larger lesions in BALB/c earlobes. These results suggest that DHT probably plays a critical role during L. mexicana infections, and the higher susceptibility of males possibly relates to benefits gained by the parasite from host-derived hormones. Our data shed new light on the physiopathology of Leishmania infections and are the first attempt to understand the direct interaction between Leishmania and androgens, particularly DHT. Understanding this trans-regulation process employed by parasites to exploit host molecules sheds new light on L. mexicana physiopathogenesis and opens a possible field for studies on drug development.