Prion Replication in the Mammalian Cytosol: Functional Regions within a Prion Domain Driving Induction, Propagation, and Inheritance

Prions of lower eukaryotes are transmissible protein particles that propagate by converting homotypic soluble proteins into growing protein assemblies. Prion activity is conferred by so-called prion domains, regions of low complexity that are often enriched in glutamines and asparagines (Q/N). The compositional similarity of fungal prion domains with intrinsically disordered domains found in many mammalian proteins raises the question of whether similar sequence elements can drive prion-like phenomena in mammals. Here, we define sequence features of the prototype Saccharomyces cerevisiae Sup35 prion domain that govern prion activities in mammalian cells by testing the ability of deletion mutants to assemble into self-perpetuating particles. Interestingly, the amino-terminal Q/N-rich tract crucially important for prion induction in yeast was dispensable for the prion life cycle in mammalian cells. Spontaneous and template-assisted prion induction, growth, and maintenance were preferentially driven by the carboxy-terminal region of the prion domain that contains a putative soft amyloid stretch recently proposed to act as a nucleation site for prion assembly. Our data demonstrate that preferred prion nucleation domains can differ between lower and higher eukaryotes, resulting in the formation of prions with strikingly different amyloid cores

Chemokine (C-C Motif) Receptor 2 Mediates Dendritic Cell Recruitment to the Human Colon but Is Not Responsible for Differences Observed in Dendritic Cell Subsets, Phenotype, and Function Between the Proximal and Distal Colon.

BACKGROUND & AIMS: Most knowledge about gastrointestinal (GI)-tract dendritic cells (DC) relies on murine studies where CD103+ DC specialize in generating immune tolerance with the functionality of CD11b+/- subsets being unclear. Information about human GI-DC is scarce, especially regarding regional specifications. Here, we characterized human DC properties throughout the human colon. METHODS: Paired proximal (right/ascending) and distal (left/descending) human colonic biopsies from 95 healthy subjects were taken; DC were assessed by flow cytometry and microbiota composition assessed by 16S rRNA gene sequencing. RESULTS: Colonic DC identified were myeloid (mDC, CD11c+CD123-) and further divided based on CD103 and SIRPα (human analog of murine CD11b) expression. CD103-SIRPα+ DC were the major population and with CD103+SIRPα+ DC were CD1c+ILT3+CCR2+ (although CCR2 was not expressed on all CD103+SIRPα+ DC). CD103+SIRPα- DC constituted a minor subset that were CD141+ILT3-CCR2-. Proximal colon samples had higher total DC counts and fewer CD103+SIRPα+ cells. Proximal colon DC were more mature than distal DC with higher stimulatory capacity for CD4+CD45RA+ T-cells. However, DC and DC-invoked T-cell expression of mucosal homing markers (β7, CCR9) was lower for proximal DC. CCR2 was expressed on circulating CD1c+, but not CD141+ mDC, and mediated DC recruitment by colonic culture supernatants in transwell assays. Proximal colon DC produced higher levels of cytokines. Mucosal microbiota profiling showed a lower microbiota load in the proximal colon, but with no differences in microbiota composition between compartments. CONCLUSIONS: Proximal colonic DC subsets differ from those in distal colon and are more mature. Targeted immunotherapy using DC in T-cell mediated GI tract inflammation may therefore need to reflect this immune compartmentalization

COPPADIS-2015 (COhort of Patients with PArkinson's DIsease in Spain, 2015), a global--clinical evaluations, serum biomarkers, genetic studies and neuroimaging--prospective, multicenter, non-interventional, long-term study on Parkinson's disease progressio

Background: Parkinson?s disease (PD) is a progressive neurodegenerative disorder causing motor and non-motor symptoms that can affect independence, social adjustment and the quality of life (QoL) of both patients and caregivers. Studies designed to find diagnostic and/or progression biomarkers of PD are needed. We describe here the study protocol of COPPADIS-2015 (COhort of Patients with PArkinson?s DIsease in Spain, 2015), an integral PD project based on four aspects/concepts: 1) PD as a global disease (motor and non-motor symptoms); 2) QoL and caregiver issues; 3) Biomarkers; 4) Disease progression.Methods/design: Observational, descriptive, non-interventional, 5-year follow-up, national (Spain), multicenter (45 centers from 15 autonomous communities), evaluation study. Specific goals: (1) detailed study (clinical evaluations, serum biomarkers, genetic studies and neuroimaging) of a population of PD patients from different areas of Spain, (2) comparison with a control group and (3) follow-up for 5 years. COPPADIS-2015 has been specifically designed to assess 17 proposed objectives. Study population: approximately 800 non-dementia PD patients, 600 principal caregivers and 400 control subjects. Study evaluations: (1) baseline includes motor assessment (e.g., Unified Parkinson?s Disease Rating Scale part III), non-motor symptoms (e.g., Non-Motor Symptoms Scale), cognition (e.g., Parkinson?s Disease Cognitive Rating Scale), mood and neuropsychiatric symptoms (e.g., Neuropsychiatric Inventory), disability, QoL (e.g., 39-item Parkinson?s disease Quality of Life Questionnaire Summary-Index) and caregiver status (e.g., Zarit Caregiver Burden Inventory); (2) follow-up includes annual (patients) or biannual (caregivers and controls) evaluations. Serum biomarkers (S-100b protein, TNF-?, IL-1, IL-2, IL-6, vitamin B12, methylmalonic acid, homocysteine, uric acid, C-reactive protein, ferritin, iron) and brain MRI (volumetry, tractography and MTAi [Medial Temporal Atrophy Index]), at baseline and at the end of follow-up, and genetic studies (DNA and RNA) at baseline will be performed in a subgroup of subjects (300 PD patients and 100 control subjects). Study periods: (1) recruitment period, from November, 2015 to February, 2017 (basal assessment); (2) follow-up period, 5 years; (3) closing date of clinical follow-up, May, 2022. Funding: Public/Private. Discussion: COPPADIS-2015 is a challenging initiative. This project will provide important information on the natural history of PD and the value of various biomarkers

Risk factors for Coronavirus disease 2019 (Covid-19) death in a population cohort study from the Western Cape province, South Africa

Risk factors for coronavirus disease 2019 (COVID-19) death in sub-Saharan Africa and the effects of human immunodeficiency virus (HIV) and tuberculosis on COVID-19 outcomes are unknown. We conducted a population cohort study using linked data from adults attending public-sector health facilities in the Western Cape, South Africa. We used Cox proportional hazards models, adjusted for age, sex, location, and comorbidities, to examine the associations between HIV, tuberculosis, and COVID-19 death from 1 March to 9 June 2020 among (1) public-sector “active patients” (≥1 visit in the 3 years before March 2020); (2) laboratory-diagnosed COVID-19 cases; and (3) hospitalized COVID-19 cases. We calculated the standardized mortality ratio (SMR) for COVID-19, comparing adults living with and without HIV using modeled population estimates.Among 3 460 932 patients (16% living with HIV), 22 308 were diagnosed with COVID-19, of whom 625 died. COVID19 death was associated with male sex, increasing age, diabetes, hypertension, and chronic kidney disease. HIV was associated with COVID-19 mortality (adjusted hazard ratio [aHR], 2.14; 95% confidence interval [CI], 1.70–2.70), with similar risks across strata of viral loads and immunosuppression. Current and previous diagnoses of tuberculosis were associated with COVID-19 death (aHR, 2.70 [95% CI, 1.81–4.04] and 1.51 [95% CI, 1.18–1.93], respectively). The SMR for COVID-19 death associated with HIV was 2.39 (95% CI, 1.96–2.86); population attributable fraction 8.5% (95% CI, 6.1–11.1)

Culture, science and bioethics: Interdisciplinary understandings of and practices in science, culture and ethics

This paper presents insights from four years of interdisciplinary discussions and analysis focusing on the complex and multidimensional character of the relationship between culture and ethics. This work started off with a clear perception of the present and cross-disciplinary importance of culture and ethics, in areas such as analysis of quality of life and familial and organizational cultures, as well as in bioprospecting, epidemiology, research ethics and clinical ethics. For example, we see the influence of culture in how contentions arise within bioprospecting linked to calls that values associated with traditional knowledge and benefit-sharing be recognised. While in studies of organisations, including healthcare organisations, we see culture explored as a tool of change and communication, and at other times as an intrinsic part of how organisations set norms, boundaries and hierarchies. This paper explores a number of ways in which understanding and responding to areas of bioethical concern benefit from a consideration of culture. It encompasses some of the ways in which each of us is engaging with those relationships in order to make the case for the necessity of thinking through how culture, science and bioethics do and should intersect. Our discussions have deepened our understanding of how interdisciplinary knowledge operates within our individual projects. They have also highlighted for us how analyses of culture, whether examining bioprospecting, epidemiology, quality of life, or perceptions of the culture-nature divide, in addition to representing particular knowledge claims, are also always challenges to present social and economic power structures that influence intellectual and academic approaches and recognition. In the following we present some of the projects discussed and developed within our emerging research network. From these examples we generate a new understanding of present challenges in on-going analyses of culture, science and ethics in today\u27s globalized society. This is supported by the broad areas of work our individual projects represent: analysis of quality of life, medical and cultural understandings of family, bioprospecting and biopiracy, epidemiology, research ethics and clinical ethics, the retention and handing back of materials gathered by archaeology (repatriation), and the quality of life and knowledge of indigenous peoples. Multiple disciplines across the social sciences study culture. Our approach to culture is one which seeks to understand how values we know as cultural – that is embedded in and emergent from particular locations and groupings of people who develop shared understandings over time – are part of how groups are recognised (or denied), how knowledge is produced and understood, how people understand their position in the world and how history and change influence the boundaries between cultures and the differential valuing of cultures. While some of us are interested in the cultural values of particular groups, this does not mean we consider some groups to be more cultural than others (and subsequently less modern than others). Likewise, while some of us are interested in objects or disputes, which seem more obviously cultural than others, we do not think that culture can only be found in such things. Instead, our overall claim is that cultural dynamics are embedded in all areas of cultural analysis and bioethical or ethical debate (bioethical we use to denote questions that revolve around medicine, healthcare and biology, while we use ethical to refer to the broader landscapes of concern some of us work in). Our theoretical approach draws mostly from work across anthropology, sociology, folklore, ethics and philosophy. In particular we draw from perspectives that engage with the significance of culture to social practice, identity and meaning, including post-colonial and native theory/indigenous peoples\u27 study. This last area of influence is very important because of the ways in which it has deconstructed the cultural underpinnings of dominant cultures\u27 claims to reason and rationality, alongside explorations of how the cultural values of dominated or marginalized groups, locations (centre versus periphery, colonial versus colonialized areas), traditions (folk traditions and livelihoods), certain academic methods or fields of studies that have been in conflict to dominant science discourses have been comparatively framed as the other to modernity and to civilisation. The structure of the paper is based around individual accounts of how we draw cultural analyses into our varied approaches to studying bioethics, ethics, science, knowledge and cultural and social lives. The aim of this structure is to provide insight into the multiple ways we can engage with the significance of culture as integrative to all areas of science and ethics. As culture is all-embracing, it represents resources intervened or inseparable from power relations, and as such, cultural analysis demands new ways of approaching areas of research interest that are reflecting inter- /trans-disciplinary analysis and competence. What the paper produces is a case for seeing culture as a vital component to how we debate science and ethics and indicates several ways this can be done analytically and methodologically

Fibril-induced glutamine-/asparagine-rich prions recruit stress granule proteins in mammalian cells

Prions of lower eukaryotes are self-templating protein aggregates that replicate by converting homotypic proteins into stable, tightly packed beta-sheet-rich protein assemblies. Propagation is mediated by prion domains, low-complexity regions enriched in polar and devoid of charged amino acid residues. In mammals, compositionally similar domains modulate the assembly of dynamic stress granules (SGs) that associate via multivalent weak interactions. Dysregulation of SGs composed of proteins with prion-like domains has been proposed to underlie the formation of pathological inclusions in several neurodegenerative diseases. The events that drive prion-like domains into transient or solid assemblies are not well understood. We studied the interactors of the prototype prion domain NM of Saccharomyces cerevisiae Sup35 in its soluble or fibril-induced prion conformation in the mammalian cytosol. We show that the interactomes of soluble and prionized NM overlap with that of SGs. Prion induction by exogenous seeds does not cause SG assembly, demonstrating that colocalization of aberrant protein inclusions with SG components does not necessarily reveal SGs as initial sites of protein misfolding

Fibril-induced glutamine-/asparagine-rich prions recruit stress granule proteins in mammalian cells

Prions of lower eukaryotes are self-templating protein aggregates that replicate by converting homotypic proteins into stable, tightly packed beta-sheet-rich protein assemblies. Propagation is mediated by prion domains, low-complexity regions enriched in polar and devoid of charged amino acid residues. In mammals, compositionally similar domains modulate the assembly of dynamic stress granules (SGs) that associate via multivalent weak interactions. Dysregulation of SGs composed of proteins with prion-like domains has been proposed to underlie the formation of pathological inclusions in several neurodegenerative diseases. The events that drive prion-like domains into transient or solid assemblies are not well understood. We studied the interactors of the prototype prion domain NM of Saccharomyces cerevisiae Sup35 in its soluble or fibril-induced prion conformation in the mammalian cytosol. We show that the interactomes of soluble and prionized NM overlap with that of SGs. Prion induction by exogenous seeds does not cause SG assembly, demonstrating that colocalization of aberrant protein inclusions with SG components does not necessarily reveal SGs as initial sites of protein misfolding

Default distrust? An fMRI investigation of the neural development of trust and cooperation.

The tendency to trust and to cooperate increases from adolescence to adulthood. This social development has been associated with improved mentalizing and age-related changes in brain function. Thus far, there is limited imaging data investigating these associations. We used two trust games with a trustworthy and an unfair partner to explore the brain mechanisms underlying trust and cooperation in subjects ranging from adolescence to mid-adulthood. Increasing age was associated with higher trust at the onset of social interactions, increased levels of trust during interactions with a trustworthy partner and a stronger decline in trust during interactions with an unfair partner. Our findings demonstrate a behavioural shift towards higher trust and an age-related increase in the sensitivity to others’ negative social signals. Increased brain activation in mentalizing regions, i.e. temporo-parietal junction, posterior cingulate and precuneus, supported the behavioural change. Additionally, age was associated with reduced activation in the reward-related orbitofrontal cortex and caudate nucleus during interactions with a trustworthy partner, possibly reflecting stronger expectations of trustworthiness. During unfair interactions, age-related increases in anterior cingulate activation, an area implicated in conflict monitoring, may mirror the necessity to inhibit pro-social tendencies in the face of the partner’s actual levels of cooperation

Molecular insights into lipid-assisted Ca2+ regulation of the TRP channel Polycystin-2

Polycystin-2 (PC2), a calcium-activated cation TRP channel, is involved in diverse Ca2+ signaling pathways. Malfunctioning Ca2+ regulation in PC2 causes autosomal-dominant polycystic kidney disease. Here we report two cryo-EM structures of distinct channel states of full-length human PC2 in complex with lipids and cations. The structures reveal conformational differences in the selectivity filter and in the large exoplasmic domain (TOP domain), which displays differing N-glycosylation. The more open structure has one cation bound below the selectivity filter (single-ion mode, PC2(SI)), whereas multiple cations are bound along the translocation pathway in the second structure (multi-ion mode, PC2(MI)). Ca2+ binding at the entrance of the selectivity filter suggests Ca2+ blockage in PC2(MI), and we observed density for the Ca2+-sensing C-terminal EF hand in the unblocked PC2(SI) state. The states show altered interactions of lipids with the pore loop and TOP domain, thus reflecting the functional diversity of PC2 at different locations, owing to different membrane compositions