https://repositorio.ufu.br/handle/123456789/5487 2026-05-25T17:25:03Z 2026-05-25T17:25:03Z https://repositorio.ufu.br/handle/123456789/48710 2026-05-22T06:21:53Z 2026-03-18T00:00:00Z

Title: O papel da NINJ1 na resposta inflamatória mediada por piroptose em Toxoplasma gondii e Neospora caninum Abstract: The innate immune system is crucial for defending against intracellular pathogens, such as Apicomplexan parasites, including Toxoplasma gondii and Neospora caninum. Programmed cell death (PCD) pathways, like pyroptosis, play a key role in limiting parasite replication and promoting inflammatory responses. Pyroptosis is characterized by inflammasome activation and gasdermin pore formation, leading to plasma membrane permeabilization. Recently, Nerve Injury-Induced Protein 1 (NINJ1) has been identified as a key mediator of terminal membrane rupture during inflammatory cell death. However, its role during Apicomplexan infections remains poorly understood. To address this, the study first conducted a review of PCD pathways in Apicomplexan parasites to identify existing knowledge gaps. It then investigated the role of NINJ1 in T. gondii and N. caninum infections. NINJ1-deficient DC2.4 cells (ΔNinj1) were generated using CRISPR-Cas9, and functional assays were performed to assess membrane permeabilization, cell lysis (via PI uptake and LDH release), and caspase-1/11 activation. Additionally, bone marrow-derived macrophages (BMDMs) from wild-type and caspase-1/11-deficient mice were used to assess inflammasome-dependent membrane permeability. Intracellular parasite burden was analyzed in DC2.4 cells and RAW 2.6.4.2 macrophages, comparing parasite replication in normal and NINJ1-deficient cells. The results showed that NINJ1 expression increases during infection and that its absence enhances parasite replication while significantly reducing cell lysis. Loss of NINJ1 did not affect caspase-1/11 activation or initial membrane permeabilization, but LDH release was greatly reduced, indicating that NINJ1 is essential for the terminal phase of plasma membrane rupture. These findings position NINJ1 as a critical effector linking inflammasome activation to terminal cellular disintegration during Apicomplexan infections.

2026-03-18T00:00:00Z https://repositorio.ufu.br/handle/123456789/48698 2026-05-16T06:23:36Z 2026-04-30T00:00:00Z

Title: Reatividade sorológica anti-toxocara em doenças reumáticas autoimunes revela supressão seletiva de IgG4 no lúpus eritematoso sistêmico Abstract: Helminth exposure has been suggested as a modulating factor in autoimmune inflammation; however, gaps remain regarding the quality of anti-helminth immune responses in autoimmune rheumatic diseases. In this study, we analyzed anti-Toxocara canis seroreactivity profiles in individuals with rheumatoid arthritis (RA), systemic lupus erythematosus (SLE), and spondyloarthritis (SpA), compared with controls, and also investigated potential clinical associations. A cross-sectional case-control study was conducted, including 442 participants. Initially, samples were tested for anti -T. canis IgG using native TES antigen, and reactive samples were subsequently evaluated using the recombinant chimeric antigen rSHORT for the detection of total IgG, IgG1, and IgG4. Disease activity was assessed using SLEDAI in SLE, and functional disability using HAQ-DI. The results demonstrated a high frequency of anti-T. canis seroreactivity in the studied population. After adjustment for demographic variables, patients with SLE showed higher odds of total IgG positivity compared with controls, whereas IgG4 seroreactivity was significantly reduced. No independent associations were observed between IgG isotypes and HAQ-DI in patients with RA or SpA. Within the SLE group, higher eosinophil levels were independently associated with lower disease activity. Overall, these findings indicate heterogeneous patterns of anti-Toxocara serological responses in autoimmune rheumatic diseases, with SLE showing the most distinctive profile, characterized by preserved total IgG responses alongside reduced IgG4 seroreactivity. Furthermore, eosinophils, rather than IgG4, were more strongly associated with lower disease activity in SLE.

2026-04-30T00:00:00Z https://repositorio.ufu.br/handle/123456789/48621 2026-04-10T06:18:04Z 2026-04-06T00:00:00Z

Title: Própolis Brasileira Frente a Patógenos Associados às Infecções Neonatais: Abordagem Antibacteriana e Antiviral Abstract: Neonatal infections represent a major global public health challenge due to high morbidity and mortality, particularly in neonatal intensive care units (NICUs). In this context, bacteria associated with sepsis and biofilm formation, opportunistic yeasts, and viruses such as Zika virus (ZIKV), which causes congenital infections and neurological alterations, stand out as clinically relevant pathogens. Accordingly, this study evaluated the in vitro antimicrobial, antibiofilm, anti–quorum sensing, and antiviral activities of the hydroethanolic extract of Brazilian red propolis (BRP) and the hydromethanolic extract of Caatinga green propolis (BGP-C) against microorganisms associated with neonatal infections. The strains evaluated included Staphylococcus epidermidis (ATCC 12228 and ATCC 14990), Staphylococcus aureus (ATCC 29213), Streptococcus pneumoniae (ATCC 6305), Streptococcus agalactiae (ATCC 13813), Streptococcus pyogenes (ATCC 19015), Enterococcus faecalis (ATCC 29212 and ATCC 51299), Listeria monocytogenes (ATCC 15313), Neisseria gonorrhoeae (ATCC 43069), Escherichia coli (ATCC BAA-198), Enterobacter cloacae (clinical isolate IAL 124), Candida albicans (ATCC 90028), and Zika virus (ZIKV), clinical isolate PE243. Antimicrobial activity was assessed by determining the minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), and minimum fungicidal concentration (MFC). Antibiofilm activity was analyzed by determining the minimum biofilm inhibitory concentration required to inhibit 50% of biofilm formation (MBIC₅₀) and the concentration that inhibited 50% of biofilm metabolic activity (IC₅₀). Morphological alterations and membrane integrity were investigated by scanning electron microscopy (SEM) and by staining with 4’,6-diamidino-2-phenylindole (DAPI) and propidium iodide (PI). Interference with quorum sensing systems was investigated using the biosensor strain Chromobacterium violaceum CV026. Antiviral activity was evaluated in Vero E6 cells and, additionally, in human trophoblast BeWo cells. Both extracts exhibited activity against Gram-positive bacteria, with MIC values ranging from 6.25 to 400 µg/mL, highlighting Streptococcus pneumoniae and Streptococcus agalactiae (6.25 µg/mL) and Listeria monocytogenes (50 µg/mL), whereas no antibacterial activity was observed against Gram-negative species. For Candida albicans, both extracts exhibited MIC and MFC values of 200 µg/mL. BRP and BGP-C reduced biofilm biomass and metabolic activity, with evidence of impaired cellular integrity and no detectable interference with AHL-dependent quorum sensing. In antiviral assays, BRP and BGP-C reduced ZIKV infectivity by approximately 34% and 40%, respectively, under non-cytotoxic conditions, with dose-dependent antiviral activity observed in BeWo cells. Overall, these findings indicate that BRP and, particularly, BGP-C represent biologically relevant natural sources with in vitro activity against pathogens associated with neonatal infections.

2026-04-06T00:00:00Z https://repositorio.ufu.br/handle/123456789/48533 2026-03-12T06:22:48Z 2026-02-24T00:00:00Z

Title: Identificação e caracterização funcional de uma nova proteína de grânulos densos em Neospora caninum por meio de edição gênica mediada por CRISPR/Cas9 Abstract: Across apicomplexan parasites, dense granule proteins are key effectors that play essential roles in intracellular parasite survival and host immune modulation, although many remain uncharacterized in Neospora caninum. In this study, we identify and characterize a novel dense granule protein of N. caninum, designated as GRA90, through integrated bioinformatic and experimental approaches. Orthology and synteny analyses demonstrated approximately 50% sequence identity with the corresponding Toxoplasma gondii orthologue, with partial conservation of structural features, indicating evolutionary relatedness with potential functional divergence. CRISPR/Cas9-mediated epitope tagging localized GRA90 to the lumen of the parasitophorous vacuole. Disruption of GRA90 significantly reduced plaque formation, reflecting compromised intracellular replication and/or survival. In a murine model, infection with Δgra90 parasites was associated with greater weight loss and decreased IFN-γ levels during the acute phase, alongside a tendency toward increased parasite burden in the brain during chronic infection. Altogether, these data identify GRA90 as a pro-host effector contributing to parasite fitness and expand current understanding of dense granule protein function in N. caninum.

2026-02-24T00:00:00Z