Advanced diagnostic and therapeutic techniques for anaesthetists in thoracic trauma: an evidence-based review.

Anaesthetists play an important role in the evaluation and treatment of patients with signs of thoracic trauma. Anaesthesia involvement can provide valuable input using both advanced diagnostic and therapeutic interventions. Commonly performed interventions may be complicated in this setting including airway management, damage control resuscitation, and acute pain management. Anaesthetists must consider additional factors including airway injuries, vascular injuries, and coagulopathy when treating this population. This evidence-based review discusses traumatic thoracic injuries with a focus on new interventions and modern anaesthesia techniques. This review further serves to support the early involvement of anaesthetists in the emergency department and other areas where they can provide value to the trauma care pathway.

Sub-Lethal Peak Exposure to Insecticides Triggers Olfaction-Mediated Avoidance in Zebrafish Larvae.

In agricultural areas, insecticides inevitably reach water bodies via leaching or run-off. While designed to be neurotoxic to insects, insecticides have adverse effects on a multitude of organisms due to the high conservation of the nervous system among phyla. To estimate the ecological effects of insecticides, it is important to investigate their impact on non-target organisms such as fish. Using zebrafish as the model, we investigated how different classes of insecticides influence fish behavior and uncovered neuronal underpinnings of the associated behavioral changes, providing an unprecedented insight into the perception of these chemicals by fish. We observed that zebrafish larvae avoid diazinon and imidacloprid while showing no response to other insecticides with the same mode of action. Moreover, ablation of olfaction abolished the aversive responses, indicating that fish smelled the insecticides. Assessment of neuronal activity in 289 brain regions showed that hypothalamic areas involved in stress response were among the regions with the largest changes, indicating that the observed behavioral response resembles reactions to stimuli that threaten homeostasis, such as changes in water chemistry. Our results contribute to the understanding of the environmental impact of insecticide exposure and can help refine acute toxicity assessment.

Common Gene Expression Patterns in Environmental Model Organisms Exposed to Engineered Nanomaterials: A Meta-Analysis.

The use of omics is gaining importance in the field of nanoecotoxicology; an increasing number of studies are aiming to investigate the effects and modes of action of engineered nanomaterials (ENMs) in this way. However, a systematic synthesis of the outcome of such studies regarding common responses and toxicity pathways is currently lacking. We developed an R-scripted computational pipeline to perform reanalysis and functional analysis of relevant transcriptomic data sets using a common approach, independent from the ENM type, and across different organisms, including Arabidopsis thaliana, Caenorhabditis elegans, and Danio rerio. Using the pipeline that can semiautomatically process data from different microarray technologies, we were able to determine the most common molecular mechanisms of nanotoxicity across extremely variable data sets. As expected, we found known mechanisms, such as interference with energy generation, oxidative stress, disruption of DNA synthesis, and activation of DNA-repair but also discovered that some less-described molecular responses to ENMs, such as DNA/RNA methylation, protein folding, and interference with neurological functions, are present across the different studies. Results were visualized in radar charts to assess toxicological response patterns allowing the comparison of different organisms and ENM types. This can be helpful to retrieve ENM-related hazard information and thus fill knowledge gaps in a comprehensive way in regard to the molecular underpinnings and mechanistic understanding of nanotoxicity.

The Regulatory T Cell Lineage Factor Foxp3 Regulates Gene Expression through Several Distinct Mechanisms Mostly Independent of Direct DNA Binding.

The lineage factor Foxp3 is essential for the development and maintenance of regulatory T cells, but little is known about the mechanisms involved. Here, we demonstrate that an N-terminal proline-rich interaction region is crucial for Foxp3's function. Subdomains within this key region link Foxp3 to several independent mechanisms of transcriptional regulation. Our study suggests that Foxp3, even in the absence of its DNA-binding forkhead domain, acts as a bridge between DNA-binding interaction partners and proteins with effector function permitting it to regulate a large number of genes. We show that, in one such mechanism, Foxp3 recruits class I histone deacetylases to the promoters of target genes, counteracting activation-induced histone acetylation and thereby suppressing their expression.

Neuropilin-1 expression on regulatory T cells enhances their interactions with dendritic cells during antigen recognition.

The interaction of T cells with dendritic cells (DCs) determines whether an immune response is launched or not. Recognition of antigen leads to formation of immunological synapses at the interface between the cells. The length of interaction is likely to determine the functional outcome, because it limits the number of MHC class II-peptide complexes that can be recruited into the synapse. Here, we show that regulatory T (Treg) cells and naive helper T (Th) cells interact differently with DCs in the absence of proinflammatory stimuli. Although differences in T cell receptor repertoire might contribute, Foxp3-induced phenotypic differences play a major role. We found that Neuropilin-1 (Nrp-1), which is expressed by most Treg cells but not naive Th cells, promoted prolonged interactions with immature DCs (iDCs), resulting in higher sensitivity to limiting amounts of antigen. This is likely to give Treg cells an advantage over naive Th cells, with the same specificity leading to a "default" suppression of immune responses in the absence of "danger signals."

LocTree3 prediction of localization.

The prediction of protein sub-cellular localization is an important step toward elucidating protein function. For each query protein sequence, LocTree2 applies machine learning (profile kernel SVM) to predict the native sub-cellular localization in 18 classes for eukaryotes, in six for bacteria and in three for archaea. The method outputs a score that reflects the reliability of each prediction. LocTree2 has performed on par with or better than any other state-of-the-art method. Here, we report the availability of LocTree3 as a public web server. The server includes the machine learning-based LocTree2 and improves over it through the addition of homology-based inference. Assessed on sequence-unique data, LocTree3 reached an 18-state accuracy Q18=80±3% for eukaryotes and a six-state accuracy Q6=89±4% for bacteria. The server accepts submissions ranging from single protein sequences to entire proteomes. Response time of the unloaded server is about 90 s for a 300-residue eukaryotic protein and a few hours for an entire eukaryotic proteome not considering the generation of the alignments. For over 1000 entirely sequenced organisms, the predictions are directly available as downloads. The web server is available at http://www.rostlab.org/services/loctree3.

Gimme shelter: the immune system during pregnancy.

Antigen-presenting molecules vary between individuals of the same species, making it more difficult for pathogens to evade immune recognition and spread through the whole population. As a result of this genetic diversity, transplants between individuals are recognized as foreign and are rejected. This alloreactivity turns placental viviparity into a major immunological challenge. The maternal immune system has to balance the opposing needs of maintaining robust immune reactivity to protect both mother and fetus from invading pathogens, while at the same time tolerating highly immunogenic paternal alloantigens in order to sustain fetal integrity. Regulatory T cells are responsible for the establishment of tolerance by modulating the immune response, and uterine natural killer cells direct placentation by controlling trophoblast invasion. A variety of other cell types, including decidual stromal cells, dendritic cells, and immunomodulatory multipotent mesenchymal stromal cells, are found at the fetal-maternal interface. These cells conspire to establish a suitable environment for fetal development without compromising systemic immunity. Defects in any of these components can lead to gestational failure despite successful fertilization.

Foxp3 expression is required for the induction of therapeutic tissue tolerance.

CD4(+)Foxp3(+) regulatory T cells (Treg) are essential for immune homeostasis and maintenance of self-tolerance. They are produced in the thymus and also generated de novo in the periphery in a TGF-ß-dependent manner. Foxp3(+) Treg are also required to achieve tolerance to transplanted tissues when induced by coreceptor or costimulation blockade. Using TCR-transgenic mice to avoid issues of autoimmune pathology, we show that Foxp3 expression is both necessary and sufficient for tissue tolerance by coreceptor blockade. Moreover, the known need in tolerance induction for TGF-ß signaling to T cells can wholly be explained by its role in induction of Foxp3, as such signaling proved dispensable for the suppressive process. We analyzed the relative contribution of TGF-ß and Foxp3 to the transcriptome of TGF-ß-induced Treg and showed that TGF-ß elicited a large set of downregulated signature genes. The number of genes uniquely modulated due to the influence of Foxp3 alone was surprisingly limited. Retroviral-mediated conditional nuclear expression of Foxp3 proved sufficient to confer transplant-suppressive potency on CD4(+) T cells and was lost once nuclear Foxp3 expression was extinguished. These data support a dual role for TGF-ß and Foxp3 in induced tolerance, in which TGF-ß stimulates Foxp3 expression, for which sustained expression is then associated with acquisition of tolerance.

Activation rather than Foxp3 expression determines that TGF-ß-induced regulatory T cells out-compete naïve T cells in dendritic cell clustering.

Regulatory T (Treg) cells are critically important for the maintenance of immunological tolerance. Both centrally arising natural nTreg cells and those emerging in the periphery in response to TGF-ß, iTreg cells, play a role in the control of unwanted immune responses. Treg cells adopt multiple mechanisms to inhibit effector T cells, yet it is unclear whether these mechanisms are shared by nTreg cells and iTreg cells alike. Here, we show that iTreg cells, like nTreg cells, are able to out-compete naïve T cells in clustering around dendritic cells (DCs). However, using both a tamoxifen-responsive inducible Foxp3 retroviral construct and TGF-ß-induced iTreg cells from hCD2-Foxp3 knock in reporter mice, we show that it is prior antigen-induced activation rather than Foxp3 expression per se that determines the ability of iTreg cells to competitively cluster around DCs. We found no difference in the capacity of iTreg cells to displace naïve T cells around DCs to that of Tr1, Th1, Th2, or Th9 cells. An important difference was, however, that clustering of iTreg cells around DCs, just as for naïve T cells, did not effectively activate DCs.

Regulatory T cells protect from autoimmune arthritis during pregnancy.

Pregnancy frequently has a beneficial effect on the autoimmune disease Rheumatoid Arthritis, ranging from improvement in clinical symptoms to complete remission. Despite decades of study, a mechanistic explanation remains elusive. Here, we demonstrate that an analogous pregnancy-induced remission can be observed in a mouse model of arthritis. We demonstrate that during pregnancy mice are protected from collagen-induced arthritis, but are still capable of launching normal immune responses to influenza infections. We examine the role of regulatory T (T(R)) cells in this beneficial effect. T(R) cells are essential for many aspects of immune tolerance, including the suppression of autoimmune responses. Remarkably, transfer of regulatory T cells from pregnant 'protected' mice was sufficient to confer protection to non-pregnant mice. These results suggest that regulatory T cells are responsible for the pregnancy-induced amelioration of arthritis.

Adverse Effects Associated with Patient-Controlled Analgesia with Ketamine Combined with Opioids and Ketamine Infusion with PCA Bolus in Postoperative Spine Patients: A Retrospective Review.

Objective: There has been increasing use of ketamine at subanesthetic doses as an adjunct to opioids in perioperative pain management. There are several known adverse drug effects (ADEs) associated with ketamine. However, the incidence of ADEs with ketamine infusions with patient-controlled analgesia (PCA) boluses compared with combined opioid and ketamine PCAs is not well described. The objectives of this study were to compare the incidence and type of ADEs in postoperative spine surgery patients on ketamine infusions with as-needed PCA boluses to patients on combined opioid and ketamine PCAs. Methods: The medical records of patients who underwent spine surgery between March 2016 and March 2020 who were postoperatively treated with a ketamine infusion and as-needed PCA boluses and parenteral opioids or treated with a combined opioid and ketamine PCA were reviewed. Perioperative information including patient characteristics and preoperative morphine equivalent daily dose (MEDD) were collected. Patient charts were reviewed for ADEs including psychological and neurological side effects, nausea, and new-onset tachycardia. Results: A total of 315 patients met the inclusion criteria and were included in the final analysis. Of these patients, 121 experienced at least one ADE (38%). Sixteen of the 68 ketamine infusion with PCA bolus patients (24%), 77 of the 203 hydromorphone and ketamine patients (38%), and 28 of the 44 morphine and ketamine patients (64%) experienced an ADE [p<0.01]. In patients with preoperative MEDD ≤ 90, nausea was the only ADE that differed significantly among the three groups. Conclusion: This retrospective analysis suggests that postoperative spine patients treated with a ketamine infusion with as-needed PCA boluses and parenteral opioids were associated with fewer ADEs when compared to an intravenous combined opioid and ketamine PCA. In patients with preoperative MEDD ≤ 90, nausea with and without emesis was the only ADE that showed statistically significant difference amongst the three groups.

Specific immunosuppression with inducible Foxp3-transduced polyclonal T cells.

Forkhead box p3 (Foxp3)-expressing regulatory T cells are key mediators of peripheral tolerance suppressing undesirable immune responses. Ectopic expression of Foxp3 confers regulatory T cell phenotype to conventional T cells, lending itself to therapeutic use in the prevention of autoimmunity and transplant rejection. Here, we show that adoptive transfer of polyclonal, wild-type T cells transduced with an inducible form of Foxp3 (iFoxp3) can be used to suppress immune responses on demand. In contrast to Foxp3-transduced cells, iFoxp3-transduced cells home "correctly" into secondary lymphoid organs, where they expand and participate in immune responses. Upon induction of iFoxp3, the cells assume regulatory T cell phenotype and start to suppress the response they initially partook in without causing systemic immunosuppression. We used this approach to suppress collagen-induced arthritis, in which conventional Foxp3-transduced cells failed to show any effect. This provides us with a generally applicable strategy to specifically halt immune responses on demand without prior knowledge of the antigens involved.

Shine a light: imaging the immune system.

Intra vital microscopy and whole-body imaging promise to revolutionize how we study the immune system. They compel by the intrinsic beauty of the images obtained and the undeniable direct biological relevance of the observations. However, it is important to remember that in many cases, fundamental insights into the underlying biological processes have already been obtained using ex vivo reductionist approaches. Indeed, it is likely that with the advent of microfluidics, new and exciting avenues will open up for ex vivo experimentation. Here, we give a brief but comprehensive overview of the various imaging techniques available, their relative strengths and shortcomings and how these tools have been used to get us to where we are today. The challenge for the future will be to apply the most suitable technology and to integrate the findings across various imaging disciplines to build a unified, comprehensive "big picture" of the immune system.

Author Correction: Proteome evolution under non-substitutable resource limitation.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Proteome evolution under non-substitutable resource limitation.

Resource limitation is a major driver of the ecological and evolutionary dynamics of organisms. Short-term responses to resource limitation include plastic changes in molecular phenotypes including protein expression. Yet little is known about the evolution of the molecular phenotype under longer-term resource limitation. Here, we combine experimental evolution of the green alga Chlamydomonas reinhardtii under multiple different non-substitutable resource limitation regimes with proteomic measurements to investigate evolutionary adaptation of the molecular phenotype. We demonstrate convergent proteomic evolution of core metabolic functions, including the Calvin-Benson cycle and gluconeogenesis, across different resource limitation environments. We do not observe proteomic changes consistent with optimized uptake of particular limiting resources. Instead, we report that adaptation proceeds in similar directions under different types of non-substitutable resource limitation. This largely convergent evolution of the expression of core metabolic proteins is associated with an improvement in the resource assimilation efficiency of nitrogen and phosphorus into biomass.

Foxp3 drives oxidative phosphorylation and protection from lipotoxicity.

Tregs can adopt a catabolic metabolic program with increased capacity for fatty acid oxidation-fueled oxidative phosphorylation (OXPHOS). It is unclear why this form of metabolism is favored in Tregs and, more specifically, whether this program represents an adaptation to the environment and developmental cues or is "hardwired" by Foxp3. Here we show, using metabolic analysis and an unbiased mass spectroscopy-based proteomics approach, that Foxp3 is both necessary and sufficient to program Treg-increased respiratory capacity and Tregs' increased ability to utilize fatty acids to fuel oxidative phosphorylation. Foxp3 drives upregulation of components of all the electron transport complexes, increasing their activity and ATP generation by oxidative phosphorylation. Increased fatty acid ß-oxidation also results in selective protection of Foxp3+ cells from fatty acid-induced cell death. This observation may provide novel targets for modulating Treg function or selection therapeutically.

Tolerance, suppression and the fetal allograft.

In solid organ transplantation the recipient immune system recognises foreign alloantigens expressed by the graft. This results in an immune attack of the transplanted organ leading to rejection, which can be prevented only by therapeutic immunosuppression. During pregnancy the fetus should also be rejected by the maternal immune system, since it expresses antigens derived from the father. Whilst the immune system retains the ability to respond to foreign antigen, tolerance mechanisms ensure that inappropriate responses against self-antigen are prevented. Maternal immune aggression directed against the fetus is partly inhibited by peripheral tolerance mechanisms that act locally to deplete cells capable of attacking the fetus. Other local mechanisms inhibit the pathways that cause tissue damage after immune activation. Recent studies in mice and humans indicate that the maternal immune system undergoes a more systemic change that promotes materno-fetal tolerance. Naturally occurring regulatory T cells, which are commonly associated with maintaining tolerance to self-antigens, can also suppress maternal allo-responses targeted against the fetus. We review the mechanisms that mediate materno-fetal tolerance, with particular emphasis on changes in regulatory T cell function during pregnancy and discuss their implications.

Peak inflammation in atherosclerosis, primary biliary cirrhosis and autoimmune arthritis is counter-intuitively associated with regulatory T cell enrichment.

Regulatory T cells (Treg) influence the development of autoimmunity and their use is increasingly proposed for clinical applications. The well-characterized suppressive potential of Treg frequently leads to the assumption that Treg presence in prevailing numbers is indicative of immunosuppression. We hypothesized that this assumption may be false. We examined models of three different diseases caused by organ-specific autoimmune responses: primary biliary cirrhosis, atherosclerosis and rheumatoid arthritis (RA). We examined indicators of relative abundance of Treg compared to pro-inflammatory T cells, during peak inflammation. In all cases, the results were compatible with a relative enrichment of Treg at the site of inflammation or its most proximal draining lymph node. Conversely, in healthy mice or mice successfully protected from disease via a Treg-mediated mechanism, the data did not suggest that any Treg accumulation was occurring. This counter-intuitive finding may appear to be at odds with the immunosuppressive nature of Treg. Yet extensive previous studies in RA show that an accumulation of Treg occurs at peak inflammation, albeit without resulting in suppression, as the Treg suppressive function is overcome by the cytokine-rich environment. We suggest that this is a ubiquitous feature of autoimmune inflammation. Treg abundance in patient samples is increasingly used as an indicator of a state of immunosuppression. We conclude that this strategy should be revisited as it may potentially be a source of misinterpretation.

An atlas of mouse CD4(+) T cell transcriptomes.

BACKGROUND: CD4(+) T cells are key regulators of the adaptive immune system and can be divided into T helper (Th) cells and regulatory T (Treg) cells. During an immune response Th cells mature from a naive state into one of several effector subtypes that exhibit distinct functions. The transcriptional mechanisms that underlie the specific functional identity of CD4(+) T cells are not fully understood. RESULTS: To assist investigations into the transcriptional identity and regulatory processes of these cells we performed mRNA-sequencing on three murine T helper subtypes (Th1, Th2 and Th17) as well as on splenic Treg cells and induced Treg (iTreg) cells. Our integrated analysis of this dataset revealed the gene expression changes associated with these related but distinct cellular identities. Each cell subtype differentially expresses a wealth of 'subtype upregulated' genes, some of which are well known whilst others promise new insights into signalling processes and transcriptional regulation. We show that hundreds of genes are regulated purely by alternative splicing to extend our knowledge of the role of post-transcriptional regulation in cell differentiation. CONCLUSIONS: This CD4(+) transcriptome atlas provides a valuable resource for the study of CD4(+) T cell populations. To facilitate its use by others, we have made the data available in an easily accessible online resource at www.th-express.org.