Biology subjects

Borges, B.

Publications and source records attributed to Borges, B..

3 recordsLinked to original sources

bioRxiv2025

In utero lipid nanoparticle delivery achieves robust editing in hematopoietic stem cells.

Efficient delivery of genome editing reagents to hematopoietic stem cells (HSCs) has limited the development of in vivo gene editing therapies for hematologic disease. Here, we exploit developmental hematopoiesis to enable HSC targeting using clinically scalable lipid nanoparticles (LNPs). During fetal development, HSCs reside in the liver, a tissue that is efficiently accessed by LNPs. We show that in utero delivery of LNPs carrying Cre recombinase or CRISPR-Cas9 components results in transfection and genome editing of bona fide long-term repopulating HSCs. Edited HSCs maintain multilineage reconstitution capacity following transplantation, demonstrating preserved stem cell function. Comparative studies reveal that both fetal and early neonatal delivery permit HSC editing, with greater efficiency during fetal liver hematopoiesis. We further identify an LNP formulation that enhance HSC targeting and enable robust neonatal HSC editing without antibody-mediated targeting. Finally, combined delivery of Cas9 via LNPs and a repair template via adeno-associated virus in neonatal mice enables in vivo homology-directed repair in multiple tissues. Together, these findings establish the perinatal period as a therapeutic window for in vivo HSC genome editing and provide a scalable strategy for treating severe early-onset hematologic diseases.

cell biology↗

bioRxiv2020

Fenbendazole controls in vitro growth, virulence potential and animal infection in the Cryptococcusmodel

The human diseases caused by the fungal pathogens Cryptococcus neoformans and C. gattii are associated with high indices of mortality, and toxic and/or cost-prohibitive therapeutic protocols. The need for affordable antifungals to combat cryptococcal disease is unquestionable. Previous studies suggested benzimidazoles as promising anti-cryptococcal agents combining low cost and high antifungal efficacy, but their therapeutic potential has not been demonstrated so far. In this study, we investigated the antifungal potential of fenbendazole, the most effective anti-cryptococcal benzimidazole. Fenbendazole was inhibitory against 30 different isolates of C. neoformans and C. gattii at a low concentration. The mechanism of anti-cryptococcal activity of fenbendazole involved microtubule disorganization, as previously described for human parasites. In combination with fenbendazole, the concentrations of the standard antifungal amphotericin B required to control cryptococcal growth were lower than those required when this antifungal was used alone. Fenbendazole was not toxic to mammalian cells. During macrophage infection, the anti-cryptococcal effects of fenbendazole included inhibition of intracellular proliferation rates and reduced phagocytic escape through vomocytosis. Fenbendazole deeply affected the cryptococcal capsule. In a mice model of cryptococcosis, the efficacy of fenbendazole to control animal mortality was similar to that observed for amphotericin B. These results indicate that fenbendazole is a promising candidate for the future development of an efficient and affordable therapeutic tool to combat cryptococcosis.

microbiology↗

bioRxiv2019

A novel protocol for the isolation of fungal extracellular vesicles reveals the participation of a putative scramblase in polysaccharide export and capsule construction in Cryptococcus gattii.

Regular protocols for the isolation of fungal extracellular vesicles (EVs) are time-consuming, hard to reproduce, and produce low yields. In an attempt to improve the protocols used for EV isolation, we explored a model of vesicle production after growth of Cryptococcus gattii and C. neoformans on solid media. Nanoparticle tracking analysis in combination with transmission electron microscopy revealed that C. gattii and C. neoformans produced EVs in solid media. These results were reproduced with an acapsular mutant of C. neoformans, as well as with isolates of Candida albicans, Histoplasma capsulatum, and Saccharomyces cerevisiae. Cryptococcal EVs produced in solid media were biologically active and contained regular vesicular components, including the major polysaccharide glucuronoxylomannan (GXM) and RNA. Since the protocol had higher yields and was much faster than the regular methods used for the isolation of fungal EVs, we asked if it would be applicable to address fundamental questions related to cryptococcal secretion. On the basis that polysaccharide export in Cryptococcus requires highly organized membrane traffic culminating with EV release, we analyzed the participation of a putative scramblase (Aim25, CNBG_3981) in EV-mediated GXM export and capsule formation in C. gattii. EVs from a C. gattii aim25{Delta} strain differed from those obtained from wild-type (WT) cells in physical-chemical properties and cargo. In a model of surface coating of an acapsular cryptococcal strain with vesicular GXM, EVs obtained from the aim25{Delta} mutant were more efficiently used as a source of capsular polysaccharides. Lack of the Aim25 scramblase resulted in disorganized membranes and increased capsular dimensions. These results associate the description of a novel protocol for the isolation of fungal EVs with the identification of a previously unknown regulator of polysaccharide release. IMPORTANCEExtracellular vesicles (EVs) are fundamental components of the physiology of cells from all kingdoms. In pathogenic fungi, they participate in important mechanisms of transfer of antifungal resistance and virulence, as well as in immune stimulation and prion transmission. However, studies on the functions of fungal EVs are still limited by the lack of efficient methods for isolation of these compartments. In this study, we developed an alternative protocol for isolation of fungal EVs and demonstrated an application of this new methodology in the study of the physiology of the fungal pathogen Cryptococcus gattii. Our results describe a fast and reliable method for the study of fungal EVs and reveal the participation of scramblase, a phospholipid translocating enzyme, in secretory processes of C. gattii.

microbiology↗