Identification of the Microbiota Metabolite, Indole, as a Novel Immune Modulator for Antigen-Presenting Cells in the Gut

Mammals are colonized by trillions of symbiotic microbes, termed the microbiota. This collection of predominantly bacteria greatly outnumbers the host’s own cells in number, genomic content, and biochemical potential. Extensive research has revealed the necessity of the microbiota for developing a fully functional intestinal and systemic immune system. While definitive crosstalk between host microbiota and immune system exists, the discrete compounds responsible for altering immune cell function remain to be fully characterized. Antigen-presenting cells (APCs) are fundamental regulators of immunity and integrate signals from their local environment to direct immune responses. Primary roles of APCs include antigen presentation to naïve T cells, tissue integrity maintenance, and cytokine secretion to instruct activity of other immune cells. APCs residing at mucosal sites have a unique role in maintaining homeostasis by promoting peripheral tolerance to harmless commensal microorganisms. The dysregulation of this phenomenon promotes chronic inflammation in the intestinal tract, which predisposes the host to numerous cancers and metabolic disorders. Identifying and manipulating the specific microbiota components that drive tolerance in the gastrointestinal tract is a primary goal of current immunological research. Indole is a microbiota-derived metabolite produced by numerous bacterial species and present at high concentrations in the intestines. Previous work from our lab and others has demonstrated a protective role of indole in the GI tract. In this study, we show that indole is able to suppress pro-inflammatory responses and promote mucosal phenotype and function in APCs. Remarkably, indole-conditioned dendritic cells (DCs) imprinted naïve T cells with gut-homing markers and preferentially induced regulatory T cells. Our overall findings reveal that indole conditions DCs towards a mucosal phenotype in a manner mechanistically distinct from the canonical GI signal, retinoic acid. In addition, indole-conditioned DCs are capable of promoting a regulatory phenotype in naïve T cells. These observations reveal a novel mechanism by which an endogenous microbiota metabolite conditions APCs for optimal function in mucosal tissues, thus providing evidence for a single metabolite promoting properties associated with peripheral tolerance. This revelation paves the way for future work in manipulating the microbiota for therapeutic potential in autoimmune and inflammatory disorders of the GI tract

Identification of the Microbiota Metabolite, Indole, as a Novel Immune Modulator for Antigen-Presenting Cells in the Gut

Mammals are colonized by trillions of symbiotic microbes, termed the microbiota. This collection of predominantly bacteria greatly outnumbers the host’s own cells in number, genomic content, and biochemical potential. Extensive research has revealed the necessity of the microbiota for developing a fully functional intestinal and systemic immune system. While definitive crosstalk between host microbiota and immune system exists, the discrete compounds responsible for altering immune cell function remain to be fully characterized. Antigen-presenting cells (APCs) are fundamental regulators of immunity and integrate signals from their local environment to direct immune responses. Primary roles of APCs include antigen presentation to naïve T cells, tissue integrity maintenance, and cytokine secretion to instruct activity of other immune cells. APCs residing at mucosal sites have a unique role in maintaining homeostasis by promoting peripheral tolerance to harmless commensal microorganisms. The dysregulation of this phenomenon promotes chronic inflammation in the intestinal tract, which predisposes the host to numerous cancers and metabolic disorders. Identifying and manipulating the specific microbiota components that drive tolerance in the gastrointestinal tract is a primary goal of current immunological research. Indole is a microbiota-derived metabolite produced by numerous bacterial species and present at high concentrations in the intestines. Previous work from our lab and others has demonstrated a protective role of indole in the GI tract. In this study, we show that indole is able to suppress pro-inflammatory responses and promote mucosal phenotype and function in APCs. Remarkably, indole-conditioned dendritic cells (DCs) imprinted naïve T cells with gut-homing markers and preferentially induced regulatory T cells. Our overall findings reveal that indole conditions DCs towards a mucosal phenotype in a manner mechanistically distinct from the canonical GI signal, retinoic acid. In addition, indole-conditioned DCs are capable of promoting a regulatory phenotype in naïve T cells. These observations reveal a novel mechanism by which an endogenous microbiota metabolite conditions APCs for optimal function in mucosal tissues, thus providing evidence for a single metabolite promoting properties associated with peripheral tolerance. This revelation paves the way for future work in manipulating the microbiota for therapeutic potential in autoimmune and inflammatory disorders of the GI tract

Addressing obstacles to the inclusion of palliative care in humanitarian health projects: a qualitative study of humanitarian health professionals’ and policy makers’ perceptions

© 2020, The Author(s). Background: Humanitarian non-governmental organizations provide assistance to communities affected by war, disaster and epidemic. A primary focus of healthcare provision by these organizations is saving lives; however, curative care will not be sufficient, appropriate, or available for some patients. In these instances, palliative care approaches to ease suffering and promote dignity are needed. Though several recent initiatives have increased the probability of palliative care being included in humanitarian healthcare response, palliative care remains minimally integrated in humanitarian health projects. Methods: We conducted a qualitative study using interpretive description methodology to investigate humanitarian policy-makers’ and health care professionals’ experiences and perceptions of palliative care during humanitarian crises. In this article, we report on the analysis of in-depth interviews with 24 participants related to their perceptions of obstacles to providing palliative care in humanitarian crises, and opportunities for overcoming these obstacles. Among the participants, 23 had experience as humanitarian health professionals, and 12 had experience with policy development and organizational decision-making. Results: Participants discussed various obstacles to the provision of palliative care in humanitarian crises. More prominent obstacles were linked to the life-saving ethos of humanitarian organizations, priority setting of scarce resources, institutional and donor funding, availability of guidance and expertise in palliative care, access to medication, and cultural specificity around death and dying. Less prominent obstacles related to continuity of care after project closure, equity, security concerns, and terminology. Conclusion: Opportunities exist for overcoming the obstacles to providing palliative care in humanitarian crises. Doing so is necessary to ensure that humanitarian healthcare can fulfill its objectives not only of saving lives, but also of alleviating suffering and promoting dignity of individuals who are ill or injured during a humanitarian crises, including persons who are dying or likely to die

Neuronal Effects of Listening to Entrainment Music Versus Preferred Music in Patients With Chronic Cancer Pain as Measured via EEG and LORETA Imaging

Previous studies examining EEG and LORETA in patients with chronic pain discovered an overactivation of high theta (6–9 Hz) and low beta (12–16 Hz) power in central regions. MEG studies with healthy subjects correlating evoked nociception ratings and source localization described delta and gamma changes according to two music interventions. Using similar music conditions with chronic pain patients, we examined EEG in response to two different music interventions for pain. To study this process in-depth we conducted a mixed-methods case study approach, based on three clinical cases. Effectiveness of personalized music therapy improvisations (entrainment music – EM) versus preferred music on chronic pain was examined with 16 participants. Three patients were randomly selected for follow-up EEG sessions three months post-intervention, where they listened to recordings of the music from the interventions provided during the research. To test the difference of EM versus preferred music, recordings were presented in a block design: silence, their own composed EM (depicting both “pain” and “healing”), preferred (commercially available) music, and a non-participant’s EM as a control. Participants rated their pain before and after the EEG on a 1–10 scale. We conducted a detailed single case analysis to compare all conditions, as well as a group comparison of entrainment-healing condition versus preferred music condition. Power spectrum and according LORETA distributions focused on expected changes in delta, theta, beta, and gamma frequencies, particularly in sensory-motor and central regions. Intentional moment-by-moment attention on the sounds/music rather than on pain and decreased awareness of pain was experienced from one participant. Corresponding EEG analysis showed accompanying power changes in sensory-motor regions and LORETA projection pointed to insula-related changes during entrainment-pain music. LORETA also indicated involvement of visual-spatial, motor, and language/music improvisation processing in response to his personalized EM which may reflect active recollection of creating the EM. Group-wide analysis showed common brain responses to personalized entrainment-healing music in theta and low beta range in right pre- and post-central gyrus. We observed somatosensory changes consistent with processing pain during entrainment-healing music that were not seen during preferred music. These results may depict top–down neural processes associated with active coping for pain

A case analysis of partnered research on palliative care for refugees in Jordan and Rwanda

© 2021, The Author(s). Background: This case analysis describes dilemmas and challenges of ethical partnering encountered in the process of conducting a research study that explored moral and practical dimensions of palliative care in humanitarian crisis settings. Two contexts are the focus of this case analysis: Jordan, an acute conflict-induced refugee situation, and Rwanda, a protracted conflict-induced refugee setting. The study’s main goal was to better understand ways humanitarian organizations and health care providers might best support ethically and contextually appropriate palliative care in humanitarian contexts. An unintended outcome of the research was learning lessons about ethical dimensions of transnational research partnerships, which is the focus of this case analysis. Discussion: There exist ongoing challenges for international collaborative research in humanitarian conflict-induced settings. Research partnerships were crucial for connecting with key stakeholders associated with the full study (e.g., refugees with life limiting illness, local healthcare providers, aid organization representatives). While important relationships were established, obstacles limited our abilities to fully attain the type of mutual partnership we aimed for. Unique challenges faced during the research included: (a) building, nurturing and sustaining respectful and equitable research partnerships between collaborators in contexts of cultural difference and global inequality; (b) appropriate ethics review and challenges of responding to local decision-maker’s research needs; and (c) equity and fairness towards vulnerable populations. Research strategies were adapted and applied to respond to these challenges with a specific focus on (d) research rewards and restitution. Conclusions: This case analysis sheds light on the importance of understanding cultural norms in all research roles, building relationships with decision makers, and developing teams that include researchers from within humanitarian crisis settings to ensure that mutually beneficial research outcomes are ethical as well as culturally and contextually relevant

Performance deficits of NK1 receptor knockout mice in the 5 choice serial reaction time task: effects of d Amphetamine, stress and time of day.

Background The neurochemical status and hyperactivity of mice lacking functional substance P-preferring NK1 receptors (NK1R-/-) resemble abnormalities in Attention Deficit Hyperactivity Disorder (ADHD). Here we tested whether NK1R-/- mice express other core features of ADHD (impulsivity and inattentiveness) and, if so, whether they are diminished by d-amphetamine, as in ADHD. Prompted by evidence that circadian rhythms are disrupted in ADHD, we also compared the performance of mice that were trained and tested in the morning or afternoon. Methods and Results The 5-Choice Serial Reaction-Time Task (5-CSRTT) was used to evaluate the cognitive performance of NK1R-/- mice and their wildtypes. After training, animals were tested using a long (LITI) and a variable (VITI) inter-trial interval: these tests were carried out with, and without, d-amphetamine pretreatment (0.3 or 1 mg/kg i.p.). NK1R-/- mice expressed greater omissions (inattentiveness), perseveration and premature responses (impulsivity) in the 5-CSRTT. In NK1R-/- mice, perseveration in the LITI was increased by injection-stress but reduced by d-amphetamine. Omissions by NK1R-/- mice in the VITI were unaffected by d-amphetamine, but premature responses were exacerbated by this psychostimulant. Omissions in the VITI were higher, overall, in the morning than the afternoon but, in the LITI, premature responses of NK1R-/- mice were higher in the afternoon than the morning. Conclusion In addition to locomotor hyperactivity, NK1R-/- mice express inattentiveness, perseveration and impulsivity in the 5-CSRTT, thereby matching core criteria for a model of ADHD. Because d-amphetamine reduced perseveration in NK1R-/- mice, this action does not require functional NK1R. However, the lack of any improvement of omissions and premature responses in NK1R-/- mice given d-amphetamine suggests that beneficial effects of this psychostimulant in other rodent models, and ADHD patients, need functional NK1R. Finally, our results reveal experimental variables (stimulus parameters, stress and time of day) that could influence translational studies

The antigenic identity of human class I MHC phosphopeptides is critically dependent upon phosphorylation status

Dysregulated post-translational modification provides a source of altered self-antigens that can stimulate immune responses in autoimmunity, inflammation, and cancer. In recent years, phosphorylated peptides have emerged as a group of tumour-associated antigens presented by MHC molecules and recognised by T cells, and represent promising candidates for cancer immunotherapy. However, the impact of phosphorylation on the antigenic identity of phosphopeptide epitopes is unclear. Here we examined this by determining structures of MHC-bound phosphopeptides bearing canonical position 4-phosphorylations in the presence and absence of their phosphate moiety, and examining phosphopeptide recognition by the T cell receptor (TCR). Strikingly, two peptides exhibited major conformational changes upon phosphorylation, involving a similar molecular mechanism, which focussed changes on the central peptide region most critical for T cell recognition. In contrast, a third epitope displayed little conformational alteration upon phosphorylation. In addition, binding studies demonstrated TCR interaction with an MHC-bound phosphopeptide was both epitope-specific and absolutely dependent upon phosphorylation status. These results highlight the critical influence of phosphorylation on the antigenic identity of naturally processed class I MHC epitopes. In doing so they provide a molecular framework for understanding phosphopeptide-specific immune responses, and have implications for the development of phosphopeptide antigen-specific cancer immunotherapy approaches