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Background: Recent studies have shown an increasing number of patients with cutaneous leishmaniasis (CL) who do not respond to pentavalent antimonials as the first line of treatment for CL. Nanocarriers such as extracellular vesicles (EVs) are efficient vehicles that might be used as drug delivery systems for the treatment of diseases. Therefore, we aimed to isolate and characterize the EVs of Leishmania major, load them with Amphotericin B (AmB), and investigate the toxicity and efficacy of the prepared drug form. Methods: The EVs of L. major were isolated, characterized, and loaded with amphotericin B (AmB), and the EVs-Amphotericin B (EVs-AmB) form was synthesized. Relevant in vitro and in vivo methods were performed to evaluate the toxicity and efficacy of EVs-AmB compared to the control. Results: The anti-leishmanial activity of the EVs-AmB showed a higher percentage inhibition (PI%) (P = 0.023) compared to the AmB at different concentrations and time points. Obtained data showed a significant increase in the lesion size and parasite load in the lesion, PBS, and EVs mice groups in comparison with EVs-AmB, AmB, and Glucantime groups (P < 0.05), EVs-AmB had a significant decrease in lesion sizes in comparison with AmB (P < 0.05). Results showed that EVs-AmB decreased its toxicity to the kidneys and liver (P < 0.05). Conclusion: EVs-AmB improved the efficacy of AmB in mouse skin lesions and reduced hepatorenal toxicity. Furthermore, EVs could be a promising nanoplatform for the delivery of AmB in CL caused by L. major. [ABSTRACT FROM AUTHOR]

Background: Cutaneous Leishmaniasis (CL) is a parasitic disease with diverse outcomes. Clinical diversity is influenced by various factors such as Leishmania species and host genetic background. The role of Leishmania RNA virus (LRV), as an endosymbiont, is suggested to not only affect the pathogenesis of Leishmania, but also impact host immune responses. This study aimed to investigate the influence of LRV2 on the expression of a number of virulence factors (VFs) of Leishmania and pro-inflammatory biomarkers. Materials and methods: Sample were obtained from CL patients from Golestan province. Leishmania species were identified by PCR (LIN 4, 17), and the presence of LRV2 was checked using the semi-nested PCR (RdRp gene). Human monocyte cell line (THP-1) was treated with three isolates of L. major with LRV2 and one isolate of L. major without LRV2. The treatments with four isolates were administered for the time points: zero, 12, 24, 36, and 48 h after co-infection. The expression levels of Leishmania VFs genes including GP63, HSP83, and MPI, as well as pro-inflammatory biomarkers genes including NLRP3, IL18, and IL1β, were measured using quantitative real-time PCR. Results: The expression of GP63, HSP83, and MPI revealed up-regulation in LRV2 + isolates compared to LRV2- isolates. The expression of the pro-inflammatory biomarkers including NLRP3, IL1β, and IL18 genes in LRV2- were higher than LRV2 + isolates. Conclusion: This finding suggests that LRV2 + may have a probable effect on the Leishmania VFs and pro-inflammatory biomarkers in the human macrophage model. [ABSTRACT FROM AUTHOR]

The present study investigated the possible role of Leishmania RNA virus 2 (LRV2) in the severity of dermal lesions and treatment failure due to Leishmania major. The drug susceptibility of 14 clinical isolates of L.major , including resistant (n = 7) and sensitive (n = 7) isolates, was checked in the J774A.1 macrophage cell line. The presence of LRV2 among isolates was investigated by the RdRp gene and semi-nested PCR. Moreover, 1 × 106 sensitive L. major LRV2+ and LRV2- promastigotes were inoculated subcutaneously into the base tails of the 40 BALB/c mice divided into 4 groups (n = 10 in each group), including clinical LRV2+, clinical LRV2-, positive control LRV2+ and negative control LRV2-. The groups were infected with a unique isolate. The lesion size and parasite burden were evaluated. Sensitive and resistant isolates were determined by the drug susceptibility method. A higher presence of LRV2 was observed among MA-resistant isolates (6/7) compared with susceptible isolates (4/7), which was not statistically significant (P = 0.237). On the other hand, a comparison of the lesion sizes between the LRV2+ and LRV2- BALB/c mice groups revealed that the mean size of the lesion in the LRV2+ groups was significantly higher than the LRV2- (P = 0.034). In the same direction, there was an increased parasite burden in mice inoculated with LRV2+ groups compared with the LRV2- BALB/c mice groups (P = 0.002). Our findings showed that the presence of LRV2 could be one of the factors contributing to exacerbating CL. Although we found a higher presence of LRV2 in the resistant isolates, it seems that further investigations are recommended to determine the detailed association between lesions' aggravation and being comparatively unresponsive to treatment. [Display omitted] • The presence of LRV2 among these isolates was detected by semi nested-PCR. • The presence of the LRV2 was observed more among Glucantime-resistant isolates (6/7) compared with susceptible isolates (4/7). • Comparison of the size of the lesions between the LRV2+ and LRV2- BALB/c mice groups revealed that the mean size of lesions in the LRV2+ groups was significantly higher than the LRV2-. [ABSTRACT FROM AUTHOR]

Cutaneous leishmaniasis (CL) is one of the most important infectious parasitic diseases in the world caused by the Leishmania parasite. In recent decades, the presence of a virus from the Totiviridae family has been proven in some Leishmania species. Although the existence of LRV2 in the Old world Leishmania species has been confirmed, almost no studies have been done to determine the potential impact of LRV2 on the immunopathogenicity of the Leishmania parasite. In this preliminary study, we measured the expression of target genes, including Glycoprotein 63 (gp63), Heat Shock Protein 70 (hsp70), Cysteine Protease b (cpb), Interleukin 1 beta (IL-1β), IL8 and IL-12 in LRV2 positive Leishmania major strain (LRV2+ L. major) and LRV2 negative L. major strain (LRV2- L. major). We exposed THP-1, a human leukemia monocytic cell line, to promastigotes of both strains. After the initial infection, RNA was extracted at different time points, and the relative gene expression was determined using a real-time quantitative reverse transcription-polymerase chain reaction (qRT-PCR). Findings showed that the presence of LRV2 in L. major was able to increase the expression of gp63, hsp70, and cpb genes; also, we observed lower levels of expression in cytokine genes of IL-1β, IL-8, IL-12 in the presence of LRV2+, which are critical factors in the host's immune response against leishmaniasis. These changes could suggest that the presence of LRV2 in L. major parasite may change the outcome of the disease and increase the probability of Leishmania survival; nevertheless, further studies are needed to confirm our results. • The presence of LRV2 in L. major parasite could increase the expression levels of GP63, HSP70, and CPb genes. • The expression of IL-1β, IL-8, and IL-12 genes was decreased in macrophage infected with LRV2+ L. major strain. [ABSTRACT FROM AUTHOR]

• Among the 181 gerbils captured, 48.6% were Leishmania spp. positive upon microscopic examination. • Leishmania infection was observed in 89.5% of the gerbils using nested-PCR. • Single or mixed infections of L. major with L. gerbilli or L. turanica were detected in 28.4% gerbils. • Homology investigation using NCBI blast against Genbank database sequences revealed 92.45–100% homology between samples and L. major in the Genbank sequences using ITS2-rDNA. Rodents from the subfamily Gerbillinae are the principal reservoir of cutaneous leishmaniasis (CL) caused by Leishmania major in the center and northeast of Iran. This study was conducted to determine both naturally occurring Leishmania infection rates and the distribution of Leishmania species in the central parts of Iran during 2019–2020. In this regard, presence of Leishmania parasites were confirmed by microscopic examination and the species were identified by nested-PCR using the Internal Transcribed Spacer2- Ribosomal DNA (ITS2-rDNA). Finally, some samples were sequenced and, the blast analysis of L. major samples, showed a 92.45–100% homology to the L. major sequence. Of the 181 wild gerbils collected (Rhombomys opimus =157 and Meriones lybicus =24), 88 (48.6%) tested positive for Leishmania sp. by microscopic examination whereas 162 (89.5%) were positive by nested-PCR. Of the 162 infected gerbils, 103 showed single strain infections (30 L. major, 28 L. gerbilli and 45 L. turanica) , 43 showed dual infections with only the non-human species (L. gerbilli and L. turanica) , and 16 were mixed infections of L. major and L. turanica (n = 14) or L. gerbilli (n = 2). All single or mixed L. major infections were detected in gerbils from areas with reports of human CL during the last decade. These findings suggest that Rhombomys opimus and Meriones libycus have a potential role in the maintenance of human and non-human transmission of Leishmania species in the CL foci. [ABSTRACT FROM AUTHOR]