Mitochondria as a therapeutic target for common pathologies.

Although the development of mitochondrial therapies has largely focused on diseases caused by mutations in mitochondrial DNA or in nuclear genes encoding mitochondrial proteins, it has been found that mitochondrial dysfunction also contributes to the pathology of many common disorders, including neurodegeneration, metabolic disease, heart failure, ischaemia-reperfusion injury and protozoal infections. Mitochondria therefore represent an important drug target for these highly prevalent diseases. Several strategies aimed at therapeutically restoring mitochondrial function are emerging, and a small number of agents have entered clinical trials. This Review discusses the opportunities and challenges faced for the further development of mitochondrial pharmacology for common pathologies

A cell-permeable biscyclooctyne as a novel probe for the identification of protein sulfenic acids

Reactive oxygen species act as important second messengers in cell signaling and homeostasis through the oxidation of protein thiols. However, the dynamic nature of protein oxidation and the lack of sensitivity of existing molecular probes have hindered our understanding of such reactions; therefore, new tools are required to address these challenges. We designed a bifunctional variant of the strained bicyclo[6.1.0]nonyne (BCN-E-BCN) that enables the tagging of intracellular protein sulfenic acids for biorthogonal copper-free click chemistry. In validation studies, BCN-E-BCN binds the sulfenylated form of the actin-severing protein cofilin, while mutation of the cognate cysteine residues abrogates its binding. BCN-E-BCN is cell permeable and reacts rapidly with cysteine sulfenic acids in cultured cells. Using different azide-tagged conjugates, we demonstrate that BCN-E-BCN can be used in various applications for the detection of sulfenylated proteins. Remarkably, cycloaddition of an azide-tagged fluorophore to BCN-E-BCN labelled proteins produced in vivo can be visualized by fluorescence microscopy to reveal their subcellular localization. These findings demonstrate a novel and multifaceted approach to the detection and trapping of sulfenic acids

Marine litter education boosts children’s understanding and self-reported actions

Marine litter is a significant environmental problem inherently linked to individuals’ purchasing, use and disposal behaviour. This research examined 176 British schoolchildren’s (aged 8–13 years) baseline marine litter understanding and self-reported actions, and tested the impact of an educational intervention. All children participated in the educational intervention and completed a pre- and post-intervention questionnaire. At baseline, children were quite concerned about marine litter and recognised some of the causes and impacts of the problem. Children also reported taking a number of actions to help solve the problem. After the intervention, children were significantly more concerned, had a better understanding of the causes and negative impacts, and reported engaging in more actions to reduce the potential causes of marine litter. Understanding the perceptions and behaviours of children is crucial as they represent current and future actors and a potentially important source of social influence among their peers, parents and community

Perspectives on the Missiological Legacy of Martin Luther and the Protestant Reformation

Upon the occasion of the 500th anniversary Martin Luther’s publication of his 95 theses, this composite article brings together five perspectives on the missiological legacy of the reformer and the subsequent Protestant Reformation. The blend of voices makes clear that Luther and the subsequent Protestant Reformation do not have a simple missiological legacy but rather various legacies: theological, ecclesiological, political, and practical; some of which co-exist, and even collide, in the same ecclesiastical community. The scandalous legacy of a splintered and splintering church remains. Yet, demonstrations of mutual recognition, reciprocal respect, and genuine fellowship can be found in certain missiological circles

Reactive oxygen species induce virus-independent MAVS-oligomerization in systemic lupus erythematosus

The increased expression of genes induced by type I interferon (IFN) is characteristic of viral infections and systemic lupus erythematosus (SLE). We showed that mitochondrial antiviral signaling (MAVS) protein, which normally forms a complex with retinoic acid gene I (RIG-I)–like helicases during viral infection, was activated by oxidative stress independently of RIG-I helicases. We found that chemically generated oxidative stress stimulated the formation of MAVS oligomers, which led to mitochondrial hyperpolarization and decreased adenosine triphosphate production and spare respiratory capacity, responses that were not observed in similarly treated cells lacking MAVS. Peripheral blood lymphocytes of SLE patients also showed spontaneous MAVS oligomerization that correlated with the increased secretion of type I IFN and mitochondrial oxidative stress. Furthermore, inhibition of mitochondrial reactive oxygen species (ROS) by the mitochondria-targeted antioxidant MitoQ prevented MAVS oligomerization and type I IFN production. ROS-dependent MAVS oligomerization and type I IFN production were reduced in cells expressing the MAVS-C79F variant, which occurs in 30% of sub-Saharan Africans and is linked with reduced type I IFN secretion and milder disease in SLE patients. Patients expressing the MAVS-C79F variant also had reduced amounts of oligomerized MAVS in their plasma compared to healthy controls. Together, our findings suggest that oxidative stress–induced MAVS oligomerization in SLE patients may contribute to the type I IFN signature that is characteristic of this syndrome

Mitochondrial superoxide generation induces a parkinsonian phenotype in zebrafish and huntingtin aggregation in human cells.

Superoxide generation by mitochondria respiratory complexes is a major source of reactive oxygen species (ROS) which are capable of initiating redox signaling and oxidative damage. Current understanding of the role of mitochondrial ROS in health and disease has been limited by the lack of experimental strategies to selectively induce mitochondrial superoxide production. The recently-developed mitochondria-targeted redox cycler MitoParaquat (MitoPQ) overcomes this limitation, and has proven effective in vitro and in Drosophila. Here we present an in vivo study of MitoPQ in the vertebrate zebrafish model in the context of Parkinson's disease (PD), and in a human cell model of Huntington's disease (HD). We show that MitoPQ is 100-fold more potent than non-targeted paraquat in both cells and in zebrafish in vivo. Treatment with MitoPQ induced a parkinsonian phenotype in zebrafish larvae, with decreased sensorimotor reflexes, spontaneous movement and brain tyrosine hydroxylase (TH) levels, without detectable effects on heart rate or atrioventricular coordination. Motor phenotypes and TH levels were partly rescued with antioxidant or monoaminergic potentiation strategies. In a HD cell model, MitoPQ promoted mutant huntingtin aggregation without increasing cell death, contrasting with the complex I inhibitor rotenone that increased death in cells expressing either wild-type or mutant huntingtin. These results show that MitoPQ is a valuable tool for cellular and in vivo studies of the role of mitochondrial superoxide generation in redox biology, and as a trigger or co-stressor to model metabolic and neurodegenerative disease phenotypes

Devise: a framework for the evaluation of internet search engines

This project investigates the feasibility of the use of user-satisfaction as a multidimensional evaluative construct of search engines. Search engine developments are reviewed to reveal a range of indexing and retrieval techniques that may assist casual users in the information retrieval task. Yet few evaluation studies have considered the impact of system features, in particular those with which the user interacts for search assistance. A broad review of retrieval system evaluation highlights the complex environment in which measures of both the utility of the search results and the usability of the system are sought from a user-perspective. Our proposed approach for a user-centered evaluation is based on a conceptual framework in which user-satisfaction is characterised as a variable dependent on system features and functions and expressed in a moderating context of user-task requirement. Towards this end, the research reported here focuses on the definition of the construct of user satisfaction on the multi dimensions of the retrieval process, an expression of what a typical user is trying to do. Empirical work was then undertaken to test the feasibility and potential value of the implementation of the framework for the evaluation of three search engines. Initial results are presented which provide a degree of understanding of how users are satisfied and on what criteria. This provides the basis on which we make recommendations for the refinement of the multidimensional framework and its use as a methodology for the evaluation of search engines from a user perspective

Detection of changes in mitochondrial hydrogen sulfide (H2S) in vivo in the fish model Poecilia mexicana (Poeciliidae)

In this paper, we outline the use of a mitochondria-targeted ratiometric mass spectrometry probe, MitoA, to detect in vivo changes in mitochondrial hydrogen sulfide (H2S) in Poecilia mexicana (family Poeciliidae). MitoA is introduced via intraperitoneal injection into the animal and is taken up by mitochondria, where it reacts with H2S to form the product MitoN. The MitoN/MitoA ratio can be used to assess relative changes in the amounts of mitochondrial H2S produced over time. We describe the use of MitoA in the fish species P. mexicana to illustrate the steps for adopting the use of MitoA in a new organism, including extraction and purification of MitoA and MitoN from tissues followed by tandem mass spectrometry. In this proof-of-concept study we exposed H2S tolerant P. mexicana to 59 µM free H2S for 5 h, which resulted in increased MitoN/MitoA in brain and gills, but not in liver or muscle, demonstrating increased mitochondrial H2S levels in select tissues following whole-animal H2S exposure. This is the first time that accumulation of H2S has been observed in vivo during whole-animal exposure to free H2S using MitoA

Photoactivated release of membrane impermeant sulfonates inside cells.

Photouncaging delivers compounds with high spatial and temporal control to induce or inhibit biological processes but the released compounds may diffuse out. We here demonstrate that sulfonate anions can be photocaged so that a membrane impermeable compound can enter cells, be uncaged by photoirradiation and trapped within the cell