Discrimination of Methionine Sulfoxide and Sulfone by Human Neutrophil Elastase

Human neutrophil elastase (HNE) is a uniquely destructive serine protease with the ability to unleash a wave of proteolytic activity by destroying the inhibitors of other proteases. Although this phenomenon forms an important part of the innate immune response to invading pathogens, it is responsible for the collateral host tissue damage observed in chronic conditions such as chronic obstructive pulmonary disease (COPD), and in more acute disorders such as the lung injuries associated with COVID-19 infection. Previously, a combinatorially selected activity-based probe revealed an unexpected substrate preference for oxidised methionine, which suggests a link to oxida-tive pathogen clearance by neutrophils. Here we use oxidised model substrates and inhibitors to confirm this observation and to show that neutrophil elastase is specifically selective for the di-oxygenated methionine sulfone rather than the mono-oxygenated methionine sulfoxide. We also posit a critical role for ordered solvent in the mechanism of HNE discrimination between the two oxidised forms methionine residue. Preference for the sulfone form of oxidised methionine is especially significant. While both host and pathogens have the ability to reduce methionine sulfoxide back to methionine, a biological pathway to reduce methionine sulfone is not known. Taken to-gether, these data suggest that the oxidative activity of neutrophils may create rapidly cleaved elas-tase “super substrates” that directly damage tissue, while initiating a cycle of neutrophil oxidation that increases elastase tissue damage and further neutrophil recruitment

Community research report

University College Cork introduced its first Community-based Participatory Research (CBPR) module in 2016. The module was funded and supported by Horizon2020 funding, specifically the EnRRICH project (Enhancing Responsible Research and Innovation through Curricula in Higher Education). The module is a 5-credit module for PhD students from all disciplines in the early stages of their PhD at University College Cork. Following two fruitful partnerships in the areas of social justice / equality, community family support services and older persons, there was a keen interested to explore partnerships in markedly different areas such as environmental sustainability. A dialogue ensued with CEF where the opportunity and feasibility to collaborate on the CBPR module was explored

Which outcome measurement instruments are used to measure core infant feeding outcomes in children up to 1 year of age? A scoping review protocol

BackgroundHow, what, and when infants are fed plays a role in the aetiology of childhood obesity. Heterogeneity in how infant feeding outcomes are measured in trials of interventions to prevent childhood obesity limits evidence syntheses and understanding of intervention effectiveness. An infant feeding core outcome set (COS) was previously developed to standardised outcome measurement and reporting. The COS represents what to measure; determining how best to measure these outcomes is the next essential step to improve intervention evaluations. The aim of this scoping review is therefore to identify what outcome measurement instruments have been used in trials, and how they have been used, to measure the core infant feeding outcomes.MethodsA scoping review will be conducted. MEDLINE, EMBASE, CINAHL, PsychINFO, the Cochrane Central Register of Controlled Trials, OpenGrey and GreyNet will be searched from inception. Papers areeligible for inclusion if they report trials involving primary data collection that measure and report at least one core infant feeding outcome in infants ≤one year of age. Following searching and screening, eligible studies will be categorised into the following four overarching categories for data extraction, synthesis and write-up: caregiver-related outcomes; diet-related outcomes; feeding environment outcomes; child weight outcomes. Data will be narratively described and presented in tabular format, with findings presented in four separate review papers delineated by the four overarching categories.DiscussionThis scoping review forms part of the Standardised measurement for Childhood Obesity Prevention (SCOPE) study (www.eiascope.com). Evidence from this scoping review on what measurement instruments are used, and how they are used, represents an essential first step in developing recommendations and guidance about how best to measure core infant feeding outcomes for childhood obesity prevention. This can improve evidence syntheses and understanding of what infant feeding interventions are most effective for childhood obesity prevention

Factors influencing use and choice of Core Outcome Sets and outcome measurement instruments in trials of interventions to prevent childhood obesity: A survey protocol

BackgroundTwo core outcome sets for childhood obesity prevention have been developed; standardised sets of outcome measurement instruments for these core outcome sets are currently being developed. Core outcome sets and standardised measurement sets can reduce heterogeneity and improve evidence syntheses for trials of interventions to prevent childhood obesity and/or interventions to improve child health behaviours related to childhood obesity. Such benefits are only realised if core outcome sets and standardised measurement sets are used in trials. The aims of this study are 1) to examine trialists’ awareness and attitudes towards the two existing core outcome sets and factors influencing their use; 2) to explore the characteristics of outcome measurement instruments that trialists currently use; and 3) to better understand how trialists choose outcome measurement instruments and the factors that influence those choices.MethodsA cross-sectional online survey will be conducted with researchers involved in the design and/or conduct of trials of interventions to prevent childhood obesity and/or to improve child health behaviours related to childhood obesity, in children aged 0 to 5 years (trialists). Trialists will be recruited using purposive sampling, and will complete a 22-item survey examining trialist characteristics, awareness of the existing core outcome sets, factors influencing use of the existing core outcome sets, characteristics of measurement instruments, how trialists choose measurement instruments, and factors influencing choice of measurement instrument. Quantitative data will be analysed descriptively; responses to open-ended questions will be analysed using qualitative content analysis.ConclusionsFindings from this study will inform approaches to maximising use of core outcome sets and standardised measurement sets for childhood obesity prevention. Use of standardised approaches to what and how outcomes are measured in this area will reduce heterogeneity and research waste and enhance evidence syntheses to better determine intervention effects

Discrimination of Methionine Sulfoxide and Sulfone by Human Neutrophil Elastase

Human neutrophil elastase (HNE) is a uniquely destructive serine protease with the ability to unleash a wave of proteolytic activity by destroying the inhibitors of other proteases. Although this phenomenon forms an important part of the innate immune response to invading pathogens, it is responsible for the collateral host tissue damage observed in chronic conditions such as chronic obstructive pulmonary disease (COPD), and in more acute disorders such as the lung injuries associated with COVID-19 infection. Previously, a combinatorially selected activity-based probe revealed an unexpected substrate preference for oxidised methionine, which suggests a link to oxidative pathogen clearance by neutrophils. Here we use oxidised model substrates and inhibitors to confirm this observation and to show that neutrophil elastase is specifically selective for the di-oxygenated methionine sulfone rather than the mono-oxygenated methionine sulfoxide. We also posit a critical role for ordered solvent in the mechanism of HNE discrimination between the two oxidised forms methionine residue. Preference for the sulfone form of oxidised methionine is especially significant. While both host and pathogens have the ability to reduce methionine sulfoxide back to methionine, a biological pathway to reduce methionine sulfone is not known. Taken together, these data suggest that the oxidative activity of neutrophils may create rapidly cleaved elastase “super substrates” that directly damage tissue, while initiating a cycle of neutrophil oxidation that increases elastase tissue damage and further neutrophil recruitment

Probing the role of methionine oxidation in substrate and inhibitor interactions with native and recombinant Human Neutrophil Elastase

This thesis was an exploration of how Human Neutrophil Elastase (HNE) activity can be modulated by oxidation of methionine residues located on substrates and inhibitors. Research focused on producing a molecular toolbox of innovative HNE substrates and inhibitors specifically engineered to include methionine, then assessing the mechanism by which oxidation leads to targeted interaction with HNE. This may be an important biochemical process in chronic obstructive pulmonary disease, which is linked to HNE destruction of elastic lung tissue together with oxidative damage by cigarette smoke and neutrophil-mediated inflammation

A novel ANCOVA design for analysis of MEG data with application to a visual attention study

Statistical inference from MEG-based distributed activation maps is well suited to the general linear modeling framework, a standard approach to the analysis of fMRI and PET neuroimaging studies. However, there are important differences from the other neuroimaging modalities related to how observations are created and fitted in GLM models, as well as how subsequent statistical inference is performed. In this paper, we demonstrate how MEG oscillatory components can be analyzed in this framework based on a custom ANCOVA modeling that takes into account baseline and inter-hemispheric effects, rather than a simpler ANOVA design. We present the methodology using as an example an MEG study of visual spatial attention, since the model design depends on the specific experiment and neuroscience hypotheses being tested. However, the techniques presented here can be readily adapted to accommodate other experimental paradigms. We create statistics that estimate the temporal evolution of attention effects on alpha power in several cortical regions. We present evidence for direction specific attention effects on alpha activity in occipital and parietal regions and demonstrate the sub-second timing of these effects in each region. The results support a mechanism for anticipatory attentional deployment that dynamically modulates the local alpha synchrony in a network of parietal control and occipital sensory regions

High yield expression in Pichia pastoris of human neutrophil elastase fused to cytochrome B5

Recombinant human neutrophil elastase (rHNE), a serine protease, was expressed in Pichia pastoris. Glycosylation sites were removed via bioengineering to prevent hyper-glycosylation (a common problem with this system) and the cDNA was codon optimized for translation in Pichia pastoris. The zymogen form of rHNE was secreted as a fusion protein with an N-terminal six histidine tag followed by the heme binding domain of Cytochrome B5 (CytB5) linked to the N-terminus of the rHNE sequence via an enteropeptidase cleavage site. The CytB5 fusion balanced the very basic rHNE (pI = 9.89) to give a colored fusion protein (pI = 6.87), purified via IMAC. Active rHNE was obtained via enteropeptidase cleavage, and purified via cation exchange chromatography, resulting in a single protein band on SDS PAGE (Mr = 25 KDa). Peptide mass fingerprinting analysis confirmed the rHNE amino acid sequence, the absence of glycosylation and the absence of an 8 amino acid C-terminal peptide as opposed to the 20 amino acids usually missing from the C-terminus of native enzyme. The yield of active rHNE was 0.41 mg/L of baffled shaker flask culture medium. Active site titration with alpha-1 antitrypsin, a potent irreversible elastase inhibitor, quantified the concentration of purified active enzyme. The Km of rHNE with methoxy-succinyl-AAPVpNA was identical with that of the native enzyme within the assay's limit of accuracy. This is the first report of full-length rHNE expression at high yields and low cost facilitating further studies on this major human neutrophil enzyme.</p