Biology subjects

Torres, M. J.

Publications and source records attributed to Torres, M. J..

7 recordsLinked to original sources

bioRxiv2024

Ovalbumin-loaded mesoporous silica nanoparticles for allergen specific immunotherapy

Allergic diseases are caused by an unnecessary immune response against harmless external substances (allergens), and they pose an important economic burden for healthcare systems with a large impact on the quality of life of patients. Allergen-specific immunotherapy (AIT) is the only treatment option capable of modifying the natural history of the disease, but current AIT schemes present safety and efficacy limitations. One possible strategy to address these limitations is to encapsulate the allergen in nanoparticle carriers that can deliver it to antigen presenting cells while hiding it from effector cells responsible for the allergic reaction. In this work, we evaluate the use of allergen-loaded mesoporous silica nanoparticles (MSNs) as AIT agents. MSNs of different pore sizes were prepared and characterized, evaluating their capacity to load and release ovalbumin (OVA) as a model allergen. Extra-large pore MSNs (XL-MSNs) showed the optimal loading and release behavior, presenting also enhanced activation of the dendritic cell line DC2.4 and reduced allergenic capacity in pre-sensitized RBL-2H3 cells, both compared to free OVA. After evaluating their biodistribution following subcutaneous, sublingual or intravenous administration, their therapeutic potential in AIT was further assessed in an in vivo murine model of OVA systemic anaphylaxis. The results showed that intravenous administration of OVA-loaded XL-MSNs significantly protected the mice from anaphylaxis and induced a Th1/Treg-immune profile, while administration through other routes failed to prevent the development of an anaphylactic reaction upon provocation with OVA. These findings establish MSNs, particularly via intravenous administration, as a promising platform to develop safer and more effective AIT.

immunology↗

bioRxiv2023

Dissolving microneedle array patches containing mesoporous silica nanoparticles of different pore sizes as a tunable sustained release platform

Dissolving microneedle array patches (DMAPs) enable efficient and painless delivery of therapeutic molecules across the stratum corneum and into the upper layers of the skin. Furthermore, this delivery strategy can be combined with the sustained release of nanoparticles to enhance the therapeutic potential in a wide variety of pathological scenarios. Among the different types of nanoparticles that can be included in microneedle formulations, mesoporous silica nanoparticles (MSNs) of tuneable pore sizes constitute a promising tool as drug delivery systems for cargos of a wide range of molecular weights. However, the development of efficient methods to produce DMAP containing large amounts of MSNs of different pore sizes has not been reported. In this work, DMAP containing MSNs with varying pore sizes was prepared and characterized. After synthesizing and characterizing MSNs, the pore size of the nanoparticles (in the range of 3 to 13 nm for S-MSN and XL-MSN, respectively) was observed to influence the loading and release of both small and large molecules, using fluorescein and ovalbumin (OVA) as model cargos. Moreover, a new preparation method was developed to produce DMAP containing large amounts of these MSNs located mainly in the microneedle tips. The successful insertion of these DMAPs was confirmed in vitro (using Parafilm), ex vivo (using excised neonatal porcine skin) and in vivo (in the back of mice) models. The dissolution of the microneedles and deposition of the nanoparticles inside the skin were also confirmed both ex vivo and in vivo using fluorescent nanoparticles, with complete microneedle dissolution after 2 h of insertion in vivo. Through histological studies, the microneedle-delivered MSNs were found to end up inside antigen presenting cells in the skin tissue (either F4/80+ macrophages or CD11c+ dendritic cells). For this reason, the uptake and biological effect of the MSNs was evaluated in vitro in dendritic cells, showing that while smaller pore MSNs were taken up by cells more efficiently (with over 80 % of S-MSN uptake compared to ca. 55 % for XL-MSNs), the dendritic cells treated with OVA- loaded XL-MSNs underwent the largest degree of activation (inducing over 25 % of CD40 expression compared to less than 2 % for OVA-loaded S- MSNs). Finally, the immune response to OVA-loaded XL-MSNs in mice was evaluated after repeated administration either subcutaneously or through DMAP. The results of this experiment showed comparable levels of anti-ovalbumin immunoglobulin generation through both routes of administration (with significant production of OVA-specific IgG1 and IgG2b antibodies), highlighting the good potential of this delivery platform for vaccination or immunotherapy applications.

pharmacology and toxicology↗

bioRxiv2023

Draft genome sequence of Microbacterium fakhimi sp. nov., a novel bacterium associated with the alga Chlamydomonas reinhardtii

Microbacterium fakhimi sp. nov. has been isolated from a contaminated algal culture (Chlamydomonas reinhardtii). Its genome has been fully sequenced (3,753,259 base pairs) and a tentative annotation is provided (3,704 genes). Both, genome information and growth tests suggest that M. fakhimi sp. nov. is auxotroph for biotin and thiamine and unable to use sulfate as sulfur (S) source. S-reduced forms, such as methionine and cysteine can support M. fakhimi sp. nov. growth. The potential biotechnological interest of this bacteria is discussed here and in a related research paper (Fakhimi et al., 2023b).

microbiology↗

bioRxiv2023

Draft genome sequence of Stenotrophomonas goyi sp. nov., a novel bacterium associated with the alga Chlamydomonas reinhardtii

Stenotrophomonas goyi sp. nov. has been isolated from a contaminated algal culture (Chlamydomonas reinhardtii). Its genome has been fully sequenced (4,487,389 base pairs) and a tentative annotation is provided (4,147 genes). The genome information suggests that S. goyi sp. nov. is unable to use sulfate and nitrate as sulfur and nitrogen sources, respectively. Growth tests have confirmed the dependence of the sulfur-containing amino acids methionine and cysteine. The potential biotechnological interest of this bacteria is discussed here and in a related research paper (Fakhimi et al., 2023b).

microbiology↗

bioRxiv2023

Chlamydomonas reinhardtii and Microbacterium fakhimi sp. nov., a mutualistic association that favor sustainable hydrogen production.

A multispecies bacterial community including Microbacterium forte sp. nov., Stenotrophomonas goyi sp. nov., and Bacillus cereus greatly promoted sustained hydrogen production by the microalga Chlamydomonas reinhardtii when cocultivated in mannitol- and yeast extract-containing medium (up to 313 mL{middle dot}L-1). Alga viability was also largely prolonged in the cocultures (>45 days) without any nutrient supplementation. Among the bacterial community, Microbacterium forte sp. nov. was the main responsible for the hydrogen production improvement. Nonetheless, the use of the entire bacterial community allowed a better growth of the alga during hydrogen production. Chlamydomonas reinhardtii and Microbacterium forte sp. nov. established a mutualistic association, based on the release of ammonium and acetic acid from the bacterium, while the alga provided sulfur-containing metabolites and complemented the bacterial auxotrophy for biotin and thiamine. This study uncovers the potential of the Chlamydomonas-bacteria consortia for durable and stable H2 production while allowing the simultaneous production of biomass.

microbiology↗

bioRxiv2019

Targeting the resolvin E1 - eicosapentaenoic acid axis improves hyperinsulinemia and hyperglycemia in a host genetic dependent manner

ObjectiveEicosapentaenoic acid (EPA) has recently garnered strong attention given the success of the REDUCE-IT trial, which overturned previous conclusions on EPA and led to its FDA approval for lowering cardiovascular disease risk. Therefore, there is a need to study EPA for cardiometabolic risk factors. Here we focused on EPAs preventative role on hyperglycemia and hyperinsulinemia. MethodsC57BL/6J male mice were fed a high fat diet in the absence or presence of pure EPA. Mass spectrometry was used to identify how EPA prevents hyperinsulinemia and hyperglycemia that drove subsequent experiments with resolvin E1 (RvE1) across inbred and outbred models. ResultsAdministration of EPA to C57BL/6J mice prevented obesity-induced glucose intolerance, hyperinsulinemia, and hyperglycemia. Supporting analyses of National Health and Nutrition Examination Survey data showed fasting glucose levels of obese adults were inversely related to EPA intake in a sex-specific manner. We next investigated how EPA improved murine hyperinsulinemia and hyperglycemia. Mass spectrometry revealed EPA overturned the obesity-driven decrement in the concentration of 18-hydroxyeicosapentaenoic acid (18-HEPE) in white adipose tissue and liver. Treatment of obese mice with RvE1, the immunoresolvant metabolite of 18-HEPE, reversed hyperinsulinemia and hyperglycemia through the G-protein coupled receptor ERV1/ChemR23. RvE1s effects were not mediated by macrophage enrichment in white adipose tissue. Finally, we determined if the metabolic effects of RvE1 were dependent on host genetics. RvE1s effects on hyperinsulinemia and hyperglycemia were divergent in diversity outbred mice that model human genetic variation. Secondary SNP analyses further revealed extensive genetic variation in human RvE1- and EPA- metabolizing genes. ConclusionsThe data suggest EPA prevents hyperinsulinemia and hyperglycemia through the endogenous bioactive metabolite RvE1 that activates ERV1/ChemR23. Importantly, the studies reveal host genetics are an overlooked but critical factor in the metabolic response to RvE1. These results underscore the need for personalized administration of EPA-derived RvE1 based on genetic/metabolic enzyme profiles.

biochemistry↗

bioRxiv2019

Amoxicillin inactivation by thiol-catalyzed cyclization reduces protein haptenation and antibacterial potency

Serum and cellular proteins are targets for the formation of adducts with the {beta}-lactam antibiotic amoxicillin. This process could be important for the development of adverse, and in particular, allergic reactions to this antibiotic. In studies exploring protein haptenation by amoxicillin, we observed that reducing agents influenced the extent of amoxicillin-protein adducts formation. Consequently, we show that thiol-containing compounds, including dithiothreitol, N-acetyl-L-cysteine and glutathione, perform a nucleophilic attack on the amoxicillin molecule that is followed by an internal rearrangement leading to amoxicillin diketopiperazine, a known amoxicillin metabolite with residual activity. The effect of thiols is catalytic and can render complete amoxicillin conversion. Interestingly, this process is dependent on the presence of an amino group in the antibiotic lateral chain, as in amoxicillin and ampicillin. Furthermore, it does not occur for other {beta}-lactam antibiotics, including cefaclor or benzylpenicillin. Biological consequences of thiol-mediated amoxicillin transformation are exemplified by a reduced bacteriostatic action and a lower capacity of thiol-treated amoxicillin to form protein adducts. Finally, modulation of the intracellular redox status through inhibition of glutathione synthesis influenced the extent of amoxicillin adduct formation with cellular proteins. These results open novel perspectives for the understanding of amoxicillin metabolism and actions, including the formation of adducts involved in allergic reactions.

pharmacology and toxicology↗