Development of antibodies against the notch ligand Delta-Like-1 by phage display with activity against breast cancer cells.

Notch signalling is a well-established oncogenic pathway, and its ligand Delta-like 1 (DLL1) is overexpressed in estrogen receptor-positive (ER) breast cancers and associated with poor patient prognosis. Hence, DLL1 has become an interesting therapeutic target for breast cancer. Here, the development of specific functional blocking anti-DLL1 antibodies with potential activity against ER breast cancer cells is reported.

Production of high-quality SARS-CoV-2 antigens: Impact of bioprocess and storage on glycosylation, biophysical attributes, and ELISA serologic tests performance.

Serological assays are valuable tools to study SARS-CoV-2 spread and, importantly, to identify individuals that were already infected and would be potentially immune to a virus reinfection. SARS-CoV-2 Spike protein and its receptor binding domain (RBD) are the antigens with higher potential to develop SARS-CoV-2 serological assays. Moreover, structural studies of these antigens are key to understand the molecular basis for Spike interaction with angiotensin converting enzyme 2 receptor, hopefully enabling the development of COVID-19 therapeutics.

Repair of Iron Centers RIC protein contributes to the virulence of Staphylococcus aureus.

RICs are a family of bacterial proteins involved in the repair of iron centers containing proteins damaged by the antimicrobial reactive species liberated by the innate immune system of infected hosts. Staphylococcus aureus is a human pathogen with increasing antibiotic resistance that also contains a RIC-like protein. In this work, we show that the survival of S.

Trichomonas vaginalis Repair of Iron Centres Proteins: The Different Role of Two Paralogs.

Trichomonas vaginalis, the causative parasite of one of the most prevalent sexually transmitted diseases is, so far, the only protozoan encoding two putative Repair of Iron Centres (RIC) proteins. Homologs of these proteins have been shown to protect bacteria from the chemical stress imposed by mammalian immunity. In this work, the biochemical and functional characterisation of the T.

Examining the antimicrobial activity and toxicity to animal cells of different types of CO-releasing molecules.

Transition metal carbonyl complexes used as CO-releasing molecules (CORMs) for biological and therapeutic applications may exhibit interesting antimicrobial activity. However, understanding the chemical traits and mechanisms of action that rule this activity is required to establish a rationale for the development of CORMs into useful antibiotics. In this work the bactericidal activity, the toxicity to eukaryotic cells, and the ability of CORMs to deliver CO to bacterial and eukaryotic cells were analysed for a set of seven CORMs that differ in the transition metal, ancillary ligands and the CO release profile.

Insights into the structure of the diiron site of RIC from Escherichia coli.

Repair of Iron Centres (RICs) are a widely-spread family of diiron proteins involved in the protection of iron-sulphur-containing enzymes from nitrosative and oxidative stress. Here, homology-based modelling was used to predict putative ligands of the RIC diiron centre in E. coli.

Escherichia coli RIC is able to donate iron to iron-sulfur clusters.

Escherichia coli RIC (Repair of Iron Centers) is a diiron protein previously reported to be involved in the repair of iron-sulfur proteins damaged by oxidative or nitrosative stresses, and proposed to act as an iron donor. This possible role of RIC was now examined specifically by evaluating its ability to donate iron ions to apo-iron-sulfur proteins, determining the iron binding constants and assessing the lability of its iron ions. We show, by UV-visible, EPR and resonance Raman spectroscopies that RIC may participate in the synthesis of an iron-sulfur cluster in the apo-forms of the spinach ferredoxin and IscU when in the presence of the sulfide donating system IscS and L-cysteine.

Role of the siderophore transporter SirABC in the Staphylococcus aureus resistance to oxidative stress.

In Staphylococcus aureus, the intracellular siderophore staphyloferrin B, which has been shown to chelate iron-bound to serum transferrin, is transported into cells by the SirABC system. In this work, we have analysed the role of the Sir transporter under stress conditions that resemble those imposed by the mammalian innate immune system. We show that exposure of S.

The bactericidal activity of carbon monoxide-releasing molecules against Helicobacter pylori.

Helicobacter pylori is a pathogen that establishes long life infections responsible for chronic gastric ulcer diseases and a proved risk factor for gastric carcinoma. The therapeutic properties of carbon-monoxide releasing molecules (CORMs) led us to investigate their effect on H. pylori.

Hybrid cluster proteins and flavodiiron proteins afford protection to Desulfovibrio vulgaris upon macrophage infection.

Desulfovibrio species are Gram-negative anaerobic sulfate-reducing bacteria that colonize the human gut. Recently, Desulfovibrio spp. have been implicated in gastrointestinal diseases and shown to stimulate the epithelial immune response, leading to increased production of inflammatory cytokines by macrophages.

Effect of combined oxidative and nitrosative stresses on Staphylococcus aureus transcriptome.

Staphylococcus aureus is a pathogen responsible for severe community- and nosocomially acquired infections. To fight pathogen intrusion, the innate immune system uses a plethora of weapons, with the generation of oxidative and nitrosative stresses among the most efficient. In this work, the S.

A role for reactive oxygen species in the antibacterial properties of carbon monoxide-releasing molecules.

Carbon monoxide-releasing molecules (CO-RMs) are, in general, transition metal carbonyl complexes that liberate controlled amounts of CO. In animal models, CO-RMs have been shown to reduce myocardial ischaemia, inflammation and vascular dysfunction, and to provide a protective effect in organ transplantation. Moreover, CO-RMs are bactericides that kill both Gram-positive and Gram-negative bacteria such as Staphylococcus aureus and Pseudomonas aeruginosa.

Bacterioferritin protects the anaerobe Desulfovibrio vulgaris Hildenborough against oxygen.

Intracellular free iron, is under aerobic conditions and via the Fenton reaction a catalyst for the formation of harmful reactive oxygen species. In this article, we analyzed the relation between intracellular iron storage and oxidative stress response in the sulfate reducing bacterium Desulfovibrio vulgaris Hildenborough, an anaerobe that is often found in oxygenated niches. To this end, we investigated the role of the iron storage protein bacterioferritin using transcriptomic and physiological approaches.

Reactive oxygen species mediate bactericidal killing elicited by carbon monoxide-releasing molecules.

CO-releasing molecules (CO-RMs) were previously shown by us to be more potent bactericides than CO gas. This suggests a mechanism of action for CO-RM, which either potentiates the activity of CO or uses another CO-RM-specific effect. We have also reported that CORM-2 induces the expression of genes related to oxidative stress.

Binding of azole antibiotics to Staphylococcus aureus flavohemoglobin increases intracellular oxidative stress.

In this work, we report that flavohemoglobin contributes to the azole susceptibility of Staphylococcus aureus. We first observed that deletion of the flavohemoglobin gene leads to an increase in the viability of imidazole-treated S. aureus cells and that reversion to the wild-type phenotype occurs upon expression of flavohemoglobin from a multicopy plasmid.

A novel nitroreductase of Staphylococcus aureus with S-nitrosoglutathione reductase activity.

In this report we show that inactivation of the putative nitroreductase SA0UHSC_00833 (ntrA) increases the sensitivity of Staphylococcus aureus to S-nitrosoglutathione (GSNO) and augments its resistance to nitrofurans. S. aureus NtrA is a bifunctional enzyme that exhibits nitroreductase and GSNO reductase activity.

Exploring the antimicrobial action of a carbon monoxide-releasing compound through whole-genome transcription profiling of Escherichia coli.

We recently reported that carbon monoxide (CO) has bactericidal activity. To understand its mode of action we analysed the gene expression changes occurring when Escherichia coli, grown aerobically and anaerobically, is treated with the CO-releasing molecule CORM-2 (tricarbonyldichlororuthenium(II) dimer). Microarray analysis shows that the E.

Flavohemoglobin of Staphylococcus aureus.

Biotically, bacteria encounter nitrogen-reactive species in environments where denitrification occurs or when nitric oxide (NO) is generated by the mammal NO synthase, particularly during the infectious processes. In bacteria, flavohemoglobins have been shown to be one of the major systems responsible for the scavenging of these chemical species, either in aerobic or in anaerobic environments. Staphylococcus aureus, a pathogenic bacterium with high impact on human heath, also contains a gene encoding a homologue of a flavohemoprotein.

Antimicrobial action of carbon monoxide-releasing compounds.

Carbon monoxide (CO) is endogenously produced in the human body, mainly from the oxidation of heme catalyzed by heme oxygenase (HO) enzymes. The induction of HO and the consequent increase in CO production play important physiological roles in vasorelaxation and neurotransmission and in the immune system. The exogenous administration of CO gas and CO-releasing molecules (CO-RMs) has been shown to induce vascular effects and to alleviate hypoxia-reoxygenation injury of mammalian cells.

Flavohemoglobin requires microaerophilic conditions for nitrosative protection of Staphylococcus aureus.

Flavohemoglobins and flavodiiron proteins are two families of enzymes involved in nitrosative detoxification. However, the physiological oxygen-related conditions under which they work and their relative role are still a matter of debate. To address this question we analyzed the function of the putative flavohemoprotein of Staphylococcus aureus, an organism that lacks a flavodiiron-like gene.