Trichomonas vaginalis extracellular vesicles up-regulate and directly transfer adherence factors promoting host cell colonization.

Trichomonas vaginalis, a common sexually transmitted parasite that colonizes the human urogenital tract, secretes extracellular vesicles (TvEVs) that are taken up by human cells and are speculated to be taken up by parasites as well. While the crosstalk between TvEVs and human cells has led to insight into host:parasite interactions, roles for TvEVs in infection have largely been one-sided, with little known about the effect of TvEV uptake by T. vaginalis. Approximately 11% of infections are found to be coinfections of multiple T. vaginalis strains. Clinical isolates often differ in their adherence to and cytolysis of host cells, underscoring the importance of understanding the effects of TvEV uptake within the parasite population. To address this question, our lab tested the ability of a less adherent strain of T. vaginalis, G3, to take up fluorescently labeled TvEVs derived from both itself (G3-EVs) and TvEVs from a more adherent strain of the parasite (B7RC2-EVs). Here, we showed that TvEVs generated from the more adherent strain are internalized more efficiently compared to the less adherent strain. Additionally, preincubation of G3 parasites with B7RC2-EVs increases parasite aggregation and adherence to host cells. Transcriptomics revealed that TvEVs up-regulate expression of predicted parasite membrane proteins and identified an adherence factor, heteropolysaccharide binding protein (HPB2). Finally, using comparative proteomics and superresolution microscopy, we demonstrated direct transfer of an adherence factor, cadherin-like protein, from TvEVs to the recipient parasites surface. This work identifies TvEVs as a mediator of parasite:parasite communication that may impact pathogenesis during mixed infections

Treatment Failure in Cutaneous Leishmaniasis Patients Referred to the School of Public Health, Tehran University of Medical Sciences During 2008–2017

Background: Cutaneous leishmaniasis (CL) is a vector borne disease predominantly found in tropical and subtropical countries, including Iran. For more than 6 decades, pentavalent antimonials have been used successfully worldwide for the treatment of leishmaniasis, but over the past few years, clinical resistance to these medications has increased. In this study, we evaluated CL patients who did not show any desirable responses to the anti-leishmanial treatment within a 10-year period (2008 to 2017). Methods: All patients from different parts of Iran suspected of having cutaneous leishmaniasis, who were referred to the laboratory of leishmaniosis in Tehran University of Medical Sciences from 2008–2017 were parasitological exam­ined. Results: During this period, a total of 1480 suspected CL patients were referred to the laboratory of leishmaniosis. Samples from 655 patients (70.8%) suspected of having CL were positive microscopically. The failure rate in patients treated with anti-leishmaniasis medications for a minimum of three complete treatment periods was 1.83% (12 cases). There was no association between the number and size of skin lesions and patient characteristics. Also, the route of drug administration had no significant effect on the number and size of lesions. Conclusion: In the present study, treatment failure was found in some confirmed CL patients treated with meglu­mine antimoniate. Over the past few years, it seems that had been increased in resistance to these medications. So, a review of the correct implementation of the treatment protocol and/or a combination therapy may be helpful in prevent­ing an increase in the rate of treatment failure

Canine Visceral Leishmaniasis in Wild Canines (Fox, Jackal, and Wolf) in Northeastern Iran Using Parasitological, Serological, and Molecular Methods

Background: Although many studies had been conducted on various aspects of canine visceral leishmaniasis (CVL) in domestic dogs in the endemic areas of Iran, investigations on CVL in wild canines are rare. Methods: This is a cross-sectional study was conducted from December 2012 to 2013 in northeast of Iran where human VL is endemic. Wild canines were trapped around the areas where human VL cases had been previously identified. Wild canines were collected and examined both clinically and serologically using direct agglutination test (DAT). Microscopically examinations were performed in all the seropositive wild canines for the presence of the amastigote form of Leishmania spp. Some Leishmania sp. which had been isolated from the spleens of wild canines, were examined analyzed by conventional PCR and sequencing techniques using α-tubulin and GAPDH genes. Results: Altogether, 84 wild canines including foxes (Vulpes vulpes, n=21), Jackals (Canis aureus, n=60) and wolves (Canis lupus, n=3) were collected. Four foxes and seven jackals showed anti-Leishmania infantum antibodies with titers of 1:320–1:20480 in DAT. Furthermore, one fox and one jackal were parasitologically (microscopy and culture) positive and L. infantum was confirmed by sequence analysis. Conclusion: The present study showed that sylvatic cycle of L. infantum had been established in the studied endemic areas of VL in northeastern Iran

Comparison of p27 Gene Expression of Promastigote and Amastigote Forms of Leishmania major (MRHO/IR/75/ER) by Real-time RT-PCR

Background: Cutaneous leishmaniasis (CL) is one of the world health problems. Leishmania major is the etiological agent of zoonotic cutaneous leishmaniasis (ZCL). Promastigote and amastigote are two morphological forms of Leishmania parasites that express different proteins and p27 is an important gene encoding cytochrome c oxidase (COX) component. P27 gene expresses a 27 kDa protein that essential in ATP synthesis. This study aimed to compare p27 gene expression in promastigote and amastigote forms in Iranian strain of L. major (MRHO/IR/75/ER). Methods: This study was conducted in 2015. Clinical isolates of CL patients from north, center, west and south parts of Iran were collected and identified by PCR-RFLP. After RNA extraction of promastigotes and amastigotes and cDNA synthesis, the expression level of p27 gene was compared by real-time RT-PCR. Results: By comparison of expression level between amastigote and promastigote forms of Iranian strain of L. major, up-regulation of p27 gene (2.73 fold) was observed in amastigotes. Moreover, there was no significant difference in p27 gene expression between L. major isolates. Conclusion: p27 gene and protein can be considered as a target in recombinant vaccine production and treatment process

Polyamine Metabolism in Leishmania Parasites: A Promising Therapeutic Target

Parasites of the genus Leishmania cause a variety of devastating and often fatal diseases in humans and domestic animals worldwide. The need for new therapeutic strategies is urgent because no vaccine is available, and treatment options are limited due to a lack of specificity and the emergence of drug resistance. Polyamines are metabolites that play a central role in rapidly proliferating cells, and recent studies have highlighted their critical nature in Leishmania. Numerous studies using a variety of inhibitors as well as gene deletion mutants have elucidated the pathway and routes of transport, revealing unique aspects of polyamine metabolism in Leishmania parasites. These studies have also shed light on the significance of polyamines for parasite proliferation, infectivity, and host–parasite interactions. This comprehensive review article focuses on the main polyamine biosynthetic enzymes: ornithine decarboxylase, S-adenosylmethionine decarboxylase, and spermidine synthase, and it emphasizes recent discoveries that advance these enzymes as potential therapeutic targets against Leishmania parasites