Disease-Dependent Local IL-10 Production Ameliorates Collagen Induced Arthritis in Mice

Rheumatoid arthritis (RA) is a chronic destructive autoimmune disease characterised by periods of flare and remission. Today’s treatment is based on continuous immunosuppression irrespective of the patient’s inflammatory status. When the disease is in remission the therapy is withdrawn but withdrawal attempts often results in inflammatory flares, and re-start of the therapy is commenced when the inflammation again is prominent which leads both to suffering and increased risk of tissue destruction. An attractive alternative treatment would provide a disease-regulated therapy that offers increased anti-inflammatory effect during flares and is inactive during periods of remission. To explore this concept we expressed the immunoregulatory cytokine interleukin (IL)-10 gene under the control of an inflammation dependent promoter in a mouse model of RA - collagen type II (CII) induced arthritis (CIA). Haematopoetic stem cells (HSCs) were transduced with lentiviral particles encoding the IL-10 gene (LNT-IL-10), or a green fluorescence protein (GFP) as control gene (LNT-GFP), driven by the inflammation-dependent IL-1/IL-6 promoter. Twelve weeks after transplantation of transduced HSCs into DBA/1 mice, CIA was induced. We found that LNT-IL-10 mice developed a reduced severity of arthritis compared to controls. The LNT-IL-10 mice exhibited both increased mRNA expression levels of IL-10 as well as increased amount of IL-10 produced by B cells and non-B APCs locally in the lymph nodes compared to controls. These findings were accompanied by increased mRNA expression of the IL-10 induced suppressor of cytokine signalling 1 (SOCS1) in lymph nodes and a decrease in the serum protein levels of IL-6. We also found a decrease in both frequency and number of B cells and serum levels of anti-CII antibodies. Thus, inflammation-dependent IL-10 therapy suppresses experimental autoimmune arthritis and is a promising candidate in the development of novel treatments for RA.     

Guided Self-Help Cognitive Behavioural Therapy for Depression in Primary Care: A Randomised Controlled Trial

Background

Access to Cognitive behavioural therapy (CBT) for depression is limited. One solution is CBT self-help books. Trial Objectives: To assess the impact of a guided self-help CBT book (GSH-CBT) on mood, compared to treatment as usual (TAU).Hypotheses:

1. GSH-CBT will have improved mood and knowledge of the causes and treatment of depression compared to the control receiving TAU
2. Guided self-help will be acceptable to patients and staff.

Methods and Findings

Participants: Adults attending seven general practices in Glasgow, UK with a BDI-II score of ≥14. 141 randomised to GSH-CBT and 140 to TAU. Interventions: RCT comparing ‘Overcoming Depression: A Five Areas Approach’ book plus 3–4 short face to face support appointments totalling up to 2 hours of guided support, compared with general practitioner TAU. Primary outcome: The BDI (II) score at 4 months. Numbers analysed: 281 at baseline, 203 at 4 months (primary outcome), 117 at 12 months. Outcome: Mean BDI-II scores were lower in the GSH-CBT group at 4 months by 5.3 points (2.6 to 7.9, p<0.001). At 4 and 12 months there were also significantly higher proportions of participants achieving a 50% reduction in BDI-II in the GSH-CBT arm. The mean support was 2 sessions with 42.7 minutes for session 1, 41.4 minutes for session 2 and 40.2 minutes of support for session 3. Adverse effects/Harms: Significantly less deterioration in mood in GSH-CBT (2.0% compared to 9.8% in the TAU group for BDI—II category change).

Limitations

Weaknesses: Our follow-up rate of 72.2% at 4 months is better than predicted but is poorer at 12 months (41.6%). In the GSH-CBT arm, around 50% of people attended 2 or fewer sessions. 22% failed to take up treatment.

Conclusions

GSH-CBT is substantially more effective than TAU.

Trial Registration

Controlled-Trials.com ISRCTN13475030     

Biotransformation of hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) by a rabbit liver cytochrome P450: insight into the mechanism of RDX biodegradation by Rhodococcus sp. strain DN22

A unique metabolite with a molecular mass of 119 Da (C(2)H(5)N(3)O(3)) accumulated during biotransformation of hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) by Rhodococcus sp. strain DN22 (D. Fournier, A. Halasz, J. C. Spain, P. Fiurasek, and J. Hawari, Appl. Environ. Microbiol. 68:166-172, 2002). The structure of the molecule and the reactions that led to its synthesis were not known. In the present study, we produced and purified the unknown metabolite by biotransformation of RDX with Rhodococcus sp. strain DN22 and identified the molecule as 4-nitro-2,4-diazabutanal using nuclear magnetic resonance and elemental analyses. Furthermore, we tested the hypothesis that a cytochrome P450 enzyme was responsible for RDX biotransformation by strain DN22. A cytochrome P450 2B4 from rabbit liver catalyzed a very similar biotransformation of RDX to 4-nitro-2,4-diazabutanal. Both the cytochrome P450 2B4 and intact cells of Rhodococcus sp. strain DN22 catalyzed the release of two nitrite ions from each reacted RDX molecule. A comparative study of cytochrome P450 2B4 and Rhodococcus sp. strain DN22 revealed substantial similarities in the product distribution and inhibition by cytochrome P450 inhibitors. The experimental evidence led us to propose that cytochrome P450 2B4 can catalyze two single electron transfers to RDX, thereby causing double denitration, which leads to spontaneous hydrolytic ring cleavage and decomposition to produce 4-nitro-2,4-diazabutanal. Our results provide strong evidence that a cytochrome P450 enzyme is the key enzyme responsible for RDX biotransformation by Rhodococcus sp. strain DN22.     

In vitro resistance mechanisms of Neisseria meningitidis against neutrophil extracellular traps

Neisseria meningitidis (Nm) is a leading cause of septicemia in childhood. Nm septicemia is unique with respect to very quick disease progression, high in vivo bacterial replication rate and its considerable mortality. Nm circumvents major mechanisms of innate immunity such as complement system and phagocytosis. Neutrophil extracellular traps (NETs) are formed from neutrophils during systemic infection and are suggested to contain invading microorganisms. Here, we investigated the interaction of Nm with NETs. Both, meningococci and spontaneously released outer membrane vesicles (SOMVs) were potent NET inducers. NETs were unable to kill NET bound meningococci, but slowed down their proliferation rate. Using Nm as model organism we identified three novel mechanisms how bacteria can evade NET‐mediated killing: (i) modification of lipid A of meningococcal LPS with phosphoethanolamine protected Nm from NET‐bound cathepsin G; (ii) expression of the high‐affinity zinc uptake receptor ZnuD allowed Nm to escape NET‐mediated nutritional immunity; (iii) binding of SOMVs to NETs saved Nm from NET binding and the consequent bacteriostatic effect. Escape from NETs may contribute to the most rapid progression of meningococcal disease. The induction of NET formation by Nm in vivo might aggravate thrombosis in vessels ultimately directing to disseminated intravascular coagulation (DIC).     

Pest management in Otago

Abstract

The Otago Regional Council could perhaps be renamed the Otago Rabbit Council. Some 35% of our budget—$8 million—goes annually towards dealing with rabbits, which certainly meet the definition of a pest (an animal which “disrupts management objectives” and lives at a population density exceeding “what society considers to be an acceptable level”). We can only hope that the day will come when we can, with confidence, say that the problem is being solved and when public and private financial inputs into rabbit control can be set at a far more reasonable level.     

“An Impediment to Living Life”: Why and How Should We Measure Stiffness in Polymyalgia Rheumatica?

Objectives

To explore patients’ concepts of stiffness in polymyalgia rheumatica (PMR), and how they think stiffness should be measured.

Methods

Eight focus groups were held at three centres involving 50 patients with current/previous PMR. Each group had at least one facilitator and one rapporteur making field notes. An interview schedule was used to stimulate discussion. Interviews were recorded, transcribed and analysed using an inductive thematic approach.

Results

Major themes identified were: symptoms: pain, stiffness and fatigue; functional impact; impact on daily schedule; and approaches to measurement. The common subtheme for the experience of stiffness was “difficulty in moving”, and usually considered as distinct from the experience of pain, albeit with a variable overlap. Some participants felt stiffness was the “overwhelming” symptom, in that it prevented them carrying out “fundamental activities” and “generally living life”. Diurnal variation in stiffness was generally described in relation to the daily schedule but was not the same as stiffness severity. Some participants suggested measuring stiffness using a numeric rating scale or a Likert scale, while others felt that it was more relevant and straightforward to measure difficulty in performing everyday activities rather than about stiffness itself.

Conclusions

A conceptual model of stiffness in PMR is presented where stiffness is an important part of the patient experience and impacts on their ability to live their lives. Stiffness is closely related to function and often regarded as interchangeable with pain. From the patients’ perspective, visual analogue scales measuring pain and stiffness were not the most useful method for reporting stiffness; participants preferred numerical rating scales, or assessments of function to reflect how stiffness impacts on their daily lives. Assessing function may be a pragmatic solution to difficulties in quantifying stiffness.     

Experts know more than just facts: eliciting functional understanding to help prioritise weed biological control targets

Prioritising investments in classical weed biological control (biocontrol) is a common decision-making challenge: biocontrol programmes can yield substantial benefits but are typically long-term and costly, and the outcome uncertain. Experts are often relied upon to help, but their role is generally restricted to providing facts and judgements to populate an existing prioritisation model, which in turn receives little scrutiny. We developed and applied a new prioritisation framework to guide biocontrol investment decisions by livestock industries that required eliciting experts’ functional understanding (including their in-depth knowledge of the theoretical and practical drivers of weed biocontrol programmes). This consultative and transparent framework drew on expertise from most biocontrol practitioners in Australia through a structured workshop, and the literature. Each of the 75 weed taxa considered was placed in a matrix according to their impact (current or potential) and the prospects of biocontrol achieving pre-defined management goals. There was considerable knowledge uncertainty regarding potential impacts, which is of concern when making pre-emptive investments. Feasibility (likelihood of finding host-specific agents) and likelihood of success (management goals being met, assuming that host-specific agents are available) of biocontrol were both assessed as low for 51 % of taxa. Predicted barriers to successful biocontrol were diverse and idiosyncratic, suggesting that application of more quantitative prioritisation approaches would be challenging. A short-list of 13 weed taxa was identified for further consideration as biocontrol targets, based on the trade-off between potential impact and prospects for biocontrol. Research priorities emerged from the prioritisation process that would maximise investment outcomes for each taxon. Only two short-listed taxa are new targets, reflecting the maturity of the biocontrol discipline targeting weeds of livestock industries in Australia. Accessing the in-depth functional understanding of experts resulted in explicit characterisation of the barriers to successful biocontrol and if/how they might be overcome, improved characterisation of uncertainty, and provided directed guidance for investment. Such an approach would be readily applicable to analogous decision-making challenges in other sectors and countries.     

Coalition Formation by Male Vervet Monkeys (Chlorocebus pygerythrus) in South Africa

Unrelated male primates frequently cohabit in bisexual groups and, despite being reproductive competitors, have been shown to cooperate in ways that are associated with reproductive success. Such coalitions between males are common in some taxa, where they can serve two primary functions – status management and improved mating opportunities – that subserve long‐ and short‐term objectives. Here, we use observational data to provide information on male coalitions in vervet monkeys (Chlorocebus pygerythrus), a guenon with a multimale group structure. We recorded a total of 62 coalitions from two troops across a 10‐mo period at Samara Game Reserve, South Africa. We found that males who were more frequently associated spatially and who had groomed one another were more likely to form coalitions and did so against higher‐ranking opponents. This was not linked to any evidence that coalitionary aggression provided either short‐ or long‐term reproductive benefits for the aggressors and coalitions were not restricted to the mating season. There was little evidence that particular individuals were targeted, reciprocation between partners was not observed, and recent immigrant males were not targeted disproportionately. Our data suggest that within‐group coalition formation between vervet males may represent something close to an ancestral state whereby males form ad hoc coalitions opportunistically, joining an ongoing dyadic contest to target an opponent without facing the possible risks of dyadic contest, such as a greater chance of injury.     

Why is the South Orkney Island shelf (the world's first high seas marine protected area) a carbon immobilization hotspot?

The Southern Ocean archipelago, the South Orkney Islands (SOI), became the world's first entirely high seas marine protected area (MPA) in 2010. The SOI continental shelf (~44 000 km²), was less than half covered by grounded ice sheet during glaciations, is biologically rich and a key area of both sea surface warming and sea‐ice losses. Little was known of the carbon cycle there, but recent work showed it was a very important site of carbon immobilization (net annual carbon accumulation) by benthos, one of the few demonstrable negative feedbacks to climate change. Carbon immobilization by SOI bryozoans was higher, per species, unit area and ice‐free day, than anywhere‐else polar. Here, we investigate why carbon immobilization has been so high at SOI, and whether this is due to high density, longevity or high annual production in six study species of bryozoans (benthic suspension feeders). We compared benthic carbon immobilization across major regions around West Antarctica with sea‐ice and primary production, from remotely sensed and directly sampled sources. Lowest carbon immobilization was at the northernmost study regions (South Georgia) and southernmost Amundsen Sea. However, data standardized for age and density showed that only SOI was anomalous (high). High immobilization at SOI was due to very high annual production of bryozoans (rather than high densities or longevity), which were 2x, 3x and 5x higher than on the Bellingshausen, South Georgia and Amundsen shelves, respectively. We found that carbon immobilization correlated to the duration (but not peak or integrated biomass) of phytoplankton blooms, both in directly sampled, local scale data and across regions using remote‐sensed data. The long bloom at SOI seems to drive considerable carbon immobilization, but sea‐ice losses across West Antarctica mean that significant carbon sinks and negative feedbacks to climate change could also develop in the Bellingshausen and Amundsen seas.