Ana Paula Drummond Rodrigues

Background: The protozoan Leishmania, in addition to infecting phagocytic cells such as macrophages, can also invade non-professional phagocytic cells like fibroblasts, a process previously described in 2D models. In a bidimensional environment, its interaction with the extracellular matrix and manipulation of endocytic processes reveal a complex ability to alter cellular entry mechanisms. However, this process in fibroblasts, especially in three-dimensional (3D) models, remains poorly understood. In vitro 3D models more accurately replicate the cellular microenvironment under physiological conditions. This study is the first to investigate the initial infection process of L. (L.) amazonensis and L. (V.) braziliensis in murine fibroblasts using a 3D model, with a comparative analysis to the 2D model.Methods: 3T3 fibroblasts were exposed to promastigotes of both Leishmania species for 5, 18, and 24 hours in 2D (plate coverslips) and 3D (type I collagen matrix) models. The infection was analyzed using immunofluorescence and confocal microscopy, which evaluated the adhesion index, actin involvement, and Rab5 recruitment—an early endosomal marker.Results: Higher adhesion of L. amazonensis was observed in 2D, while L. braziliensis adhered more in 3D. Membrane protrusions (filopodia and lamellipodia) were seen near the parasites, indicating cytoskeletal activity. Rab5 was strongly recruited around L. amazonensis in the 3D model, whereas its labeling was weak in the control groups and the L. braziliensis 3D group. In the 2D model, Rab5 labelling was more pronounced in both infected groups. Throughout the interaction periods, Rab5 played a more prominent role in the entry of L. amazonensis, suggesting that actin’s secondary participation was involved. In contrast, L. braziliensis appeared to rely more heavily on actin-dependent entry routes, particularly at 24 hours.Conclusions: These novel findings reveal that distinct Leishmania species utilize specialized invasion strategies, adapting to both host cell type and experimental conditions. This underscores the role of species-specific biological traits in modulating host cell entry mechanisms, which may, in turn, influence the varied clinical manifestations associated with each species.

The online version contains supplementary material available at 10.1186/s12866-025-04098-x.

This study employs advanced three‐dimensional electron microscopy techniques, including Transmission Electron Microscopy (TEM) tomography and freeze‐fracture imaging via scanning electron microscopy (SEM), to investigate the ultrastructural organization of Cyrilia lignieresi‐infected red blood cells (iRBCs) in the host fish Synbranchus marmoratus. The analysis focuses on the parasitophorous vacuole (PV) and reveals a highly complex intravacuolar membranous network (IVN) composed of vesicles, tubules, and interconnected membranous structures. These elements exhibit considerable diversity in size, morphology, and electron density, suggesting dynamic functional roles in the parasite–host interaction. The electron tomography and three‐dimensional reconstructions data provide unprecedented insights into the spatial organization and potential functional significance of these membranous systems. These findings not only enhance our understanding of the cellular adaptations of C. lignieresi but also contribute to a broader knowledge of apicomplexan parasitism and host–pathogen interactions.

O volume 13 de “Tópicos Especiais em Engenharia: inovações e avanços tecnológicos” reúne contribuições que refletem o panorama atual da Engenharia em áreas de aplicabilidade prática e em contínua evolução tecnológica. Este volume apresenta abordagens em segurança e inovação, explorando desde a estabilidade em espaços matemáticos complexos em problemas de fronteira até aplicações de automação e acessibilidade residencial. A segurança no trabalho e a implementação de ferramentas para sensores de rede ganham destaque, assim como o desenvolvimento de uma ferramenta voltada ao processamento de coco babaçu, com potencial para apoiar atividades econômicas locais. No setor de saúde, a pesquisa sobre membranas de quitosana e scaffolds de policaprolactona oferece soluções para tratamento de feridas e viabilidade celular, ampliando as perspectivas para materiais biomédicos. A análise de grandes volumes de dados surge como elemento-chave na otimização de campanhas de marketing em saúde, enquanto o estudo do fluxo veicular em rodovias e a integração do eSocial nas empresas refletem demandas de infraestrutura e normativas atuais. Combinando fundamentos teóricos e aplicações práticas, esta obra é uma contribuição que agrega conhecimento e inovações tecnológicas em diversos setores, servindo de referência para profissionais e pesquisadores em busca de abordagens interdisciplinares e soluções tecnológicas. %

Juruaça virus (JUAV), previously unclassified, was isolated from bats and administered to neonatal and adult BALB/c mice to investigate acute and chronic disease progression. In this study, we conducted genomic sequencing to achieve taxonomic classification and utilized these models to explore the inflammatory response and sickness behavior in both neonatal and adult mice. Neonates received a single intranasal instillation of infected brain homogenate (20 µL), whereas 31-day-old mice were given the same volume intranasally for three consecutive days. Control groups were administered equal volumes of uninfected brain homogenate. Our findings reveal that intranasal JUAV infection-induced acute meningoencephalitis and death in neonates, while adult mice exhibited chronic infection with variable clinical signs, inflammatory mediator production, histopathological changes, and neuropathological features. Interestingly, only some adult mice showed sickness behavior post-infection, and among these, a subset continued to decline and die. The differential tissue damage observed in mice with and without overt disease symptoms suggests mechanisms of resistance or tolerance, where exceeding tolerance capacity resulted in pathological outcomes, including chronic dysfunction or death. This study provides the first evidence of JUAV’s capability to infect mammals, demonstrating its distinct impact on bats and variable effects in neonatal and adult mice. We provisionally classified JUAV as closely related to the clade containing tombus-like virus 6 found in mute swan feces. Our research highlights the importance of understanding viral–host interactions and the inflammatory responses that contribute to disease variability, offering insights into tolerance and resistance mechanisms based on inflammatory response modulation.

The efficacy of pregabalin in pain treatment has led to the search for new formulations for its use through different routes of administration. This study aimed to prepare, characterize, and evaluate the cytotoxicity of pregabalin (PG) gels for topical application in the oral cavity. Solutions with three different concentrations of PG were prepared and added to a 1.0% carbopol gel base. Thermal analyses (TG and DSC) and FTIR were performed on the gel and pure pregabalin. Stability (preliminary and accelerated) and rheology studies were also conducted on the gels. Cytotoxicity was evaluated in human gingival fibroblasts in the following groups: WG (1.0% carbopol gel base), PG2G (2.0% pregabalin gel), PG5G (5.0% pregabalin gel), and PG10G (10% pregabalin gel). A transparent and homogeneous gel with a pH of 6 was obtained. The formulations showed stability, and the different drug concentrations did not influence the product’s characteristics. None of the tested groups showed cytotoxicity for the analyzed cells. The pregabalin gels exhibited favorable and non-toxic characteristics for human gingival fibroblasts in vitro. Therefore, this product may be a promising therapeutic alternative for topical application in the oral mucosa.

Haemogregarine (Apicomplexa: Adeleorina) parasites are considered to be the most common and widespread haemoparasites in reptiles. The genus Hepatozoon (Apicomplexa: Adeleorina: Hepatozoidae) can be found parasitizing a broad range of species and, in reptiles, they infect mainly peripheral blood erythrocytes. The present study detected and characterized a haemogregarine isolated from the lizard species, Ameiva ameiva, collected from the municipality of Capanema, Pará state, north Brazil. Blood smears and imprints from lungs, brain, heart, kidney, liver, bone marrow and spleen were observed using light microscopy and the parasite was genetically identified by molecular analysis. Morphological, morphometric and molecular data were obtained. Parasite gamonts were found in 49.5% (55/111) of the blood smears from A. ameiva, and were characterized as oval, averaging 12.0 ± 0.8 × 5.9 ± 0.6 μm² in size, which displaced the nuclei of parasitized monocytes laterally. Parasite forms resembling immature gamonts were observed in the spleen and bone marrow of the lizards. Furthermore, phylogenetic analyses of 18S rRNA sequences did not reveal gene similarity with other Hepatozoon spp. sequences from reptiles. Thus, morphological and molecular analyses have identified a new species of Hepatozoon parasite, Hepatozoon lainsoni sp. nov., which infects monocytes of the A. ameiva lizard.

Leishmaniasis encompasses a cluster of neglected tropical diseases triggered by kinetoplastid phatogens belonging to the genus Leishmania. Current therapeutic approaches are toxic, expensive, and require long-term treatment. Nanoparticles are emerging as a new alternative for the treatment of neglected tropical diseases. Silk Fibroin is a biocompatible and amphiphilic protein that can be used for formulating nanoemulsions, while kojic acid is a secondary metabolite with antileishmanial actions. Thus, this study evaluated the efficacy of a nanoemulsion, formulated with silk fibroin as the surfactant and containing kojic acid (NanoFKA), against promastigote and amastigote forms of Leishmania (Leishmania) amazonensis. The NanoFKA had an average particle size of 176 nm, Polydispersity Index (PDI) of 0.370, and a Zeta Potential of −32.3 mV. It presented inhibitory concentration (IC₅₀) values of >56 μg/mL and >7 μg/mL for the promastigote and amastigote forms, respectively. Ultrastructural analysis, cell cycle distribution and phosphatidylserine exposure showed that NanoFKA treatment induces apoptosis-like cell death and cell cycle arrest in L. (L.) amazonensis. In addition, NanoFKA exhibited no cytotoxicity against macrophages. Given these results, NanoFKA present leishmanicidal activity against L. (L.) amazonensis.

(1) Background: Leishmaniasis refers to a group of anthropozoonotic diseases caused by Leishmania. The major chemotherapeutic agent used for its treatment is Glucantime^®®, but the search continues for new compounds that are economically viable and act on the protozoan without causing damage to the host cell. As an alternative approach, this study used a combination of copaiba oil (CO) and kojic acid (KA) to determine their in vitro action on host cells, on the Leishmania (Leishmania) amazonensis protozoan and its interaction with macrophages. (2) Methods: In vitro culture, analysis of cytokine release and microscopy assays were performed. Statistical analysis was performed with ANOVA (GraphPad Prism). (3) Results: The combination did not induce cytotoxic effects on macrophages after treatment but promoted morphological changes in the protozoan, such as nuclear alterations (apoptotic characteristics), alterations in the cellular body and an increase in the number of electrodense structures and acidocalcisomes, observed mainly at the concentrations of CO20KA50 and CO30KA50 μg/mL. We observed reductions in the intracellular amastigote number and in the production of proinflammatory cytokines, such as IL-6 and TNF-α, after treatment with CO30KA at 50 µg/mL. (4) Conclusions: We report here, for the first time, that the combination of CO and KA may be a promising approach against Leishmania (Leishmania) amazonensis.

Bone tissue is one of the most important in the human body. In this study, scaffolds of poly (lactic acid) PLA reinforced with hydroxyapatite (HA) and carbon nanotubes (CNT) were manufactured, evaluating their mechanical and biological properties. HA was synthesized by wet method and characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM). The scaffolds were produced using additive manufacturing and characterized by optical microscopy, SEM, thermogravimetric analysis (TGA), Raman spectroscopy and biological tests. The SEM results showed that the PLA surface was affected by the incorporation of CNT. TG showed that the incorporation of HA into the polymer matrix compromised the thermal stability of PLA. On the other hand, the incorporation of CNT to the polymer and the impregnation with HA on the surface by thermal effect increased the stability of PLA/CNT scaffolds. Raman spectra indicated that HA impregnation on the surface did not modify the polymer or the ceramic. In the compression tests, PLA and PLA/CNT scaffolds displayed the best compressive strength. In the biological tests, more than 85% of the cells remained viable after 48 h of incubation with all tested scaffolds and groups with CNT in the composition disclosing the best results.