Inhibiting presynaptic calcium channel motility in the auditory cortex suppresses synchronized input processing.

Introduction: The emergent coherent population activity from thousands of stochastic neurons in the brain is believed to constitute a key neuronal mechanism for salient processing of external stimuli and its link to internal states like attention and perception. In the sensory cortex, functional cell assemblies are formed by recurrent excitation and inhibitory influences. The stochastic dynamics of each cell involved is largely orchestrated by presynaptic CAV2.1 voltage-gated calcium channels (VGCCs). Cav2.1 VGCCs initiate the release of neurotransmitters from the presynaptic compartment and are therefore able to add variability into synaptic transmission which can be partly explained by their mobile organization around docked vesicles. Methods: To investigate the relevance of Cav2.1 channel surface motility for the input processing in the primary auditory cortex (A1) in vivo, we make use of a new optogenetic system which allows for acute, reversable cross-linking Cav2.1 VGCCs via a photo-cross-linkable cryptochrome mutant, CRY2olig. In order to map neuronal activity across all cortical layers of the A1, we performed laminar current-source density (CSD) recordings with varying auditory stimulus sets in transgenic mice with a citrine tag on the N-terminus of the VGCCs. Results: Clustering VGCCs suppresses overall sensory-evoked population activity, particularly when stimuli lead to a highly synchronized distribution of synaptic inputs. Discussion: Our findings reveal the importance of membrane dynamics of presynaptic calcium channels for sensory encoding by dynamically adjusting network activity across a wide range of synaptic input strength.

Chronic Disease in Low-Resource Settings: Prevention and Management Throughout the Continuum of Care-A Call for Papers.

Multimorbidity, defined as the presence of two or more chronic conditions in an individual, has become a global public health challenge [...].

Interactive nanocluster compaction of the ELKS scaffold and Cacophony Ca2+ channels drives sustained active zone potentiation.

At presynaptic active zones (AZs), conserved scaffold protein architectures control synaptic vesicle (SV) release by defining the nanoscale distribution and density of voltage-gated Ca2+ channels (VGCCs). While AZs can potentiate SV release in the minutes range, we lack an understanding of how AZ scaffold components and VGCCs engage into potentiation. We here establish dynamic, intravital single-molecule imaging of endogenously tagged proteins at Drosophila AZs undergoing presynaptic homeostatic potentiation. During potentiation, the numbers of α1 VGCC subunit Cacophony (Cac) increased per AZ, while their mobility decreased and nanoscale distribution compacted. These dynamic Cac changes depended on the interaction between Cac channel's intracellular carboxyl terminus and the membrane-close amino-terminal region of the ELKS-family protein Bruchpilot, whose distribution compacted drastically. The Cac-ELKS/Bruchpilot interaction was also needed for sustained AZ potentiation. Our single-molecule analysis illustrates how the AZ scaffold couples to VGCC nanoscale distribution and dynamics to establish a state of sustained potentiation.

Patient-Reported Outcome Measures in Key Sub-Saharan African Languages to Promote Diversity: A Scoping Review.

OBJECTIVES: Sub-Saharan Africa is a world region rich and diverse in cultures and languages; yet, it is also challenged with regard to resources that may facilitate the cultural adaptation or development of patient-reported outcome measures (PROMs). Systematic exclusion of patients' "voices," because of gaps in the availability of PROMs, may perpetuate health inequity. Hence, the objective is to describe the availability of PROMs in the non-English, sub-Saharan African languages. METHODS: A scoping review was conducted to identify PROMs that had been translated, validated, or developed for use in 32 selected, non-English, sub-Saharan African languages pertaining to health outcomes. Four databases were searched (May 7, 2021), and additional articles were identified through reference screening and via corresponding authors. Data were extracted in terms of country, language, population, construct, and PROM characteristics (eg, number of items). RESULTS: A total of 220 unique articles were included from 7451 records, leading to the identification of 126 unique PROMs. Most studies were conducted in either Ethiopia, Nigeria, or South Africa. As such, prevalent languages included Amharic, Yoruba, and non-English languages common to South Africa (eg, Setswana, Xhosa, and Zulu). No PROMs were identified in any of the languages for 27 sub-Saharan African countries or 10 of the 32 included languages. CONCLUSIONS: There are significant gaps in the availability of PROMs across the non-English African languages included. Nevertheless, the PROMs that were identified largely align with core outcome sets relevant to the prevalent disease burden in this world region. Consensus-based priority setting may inform the most pertinent gaps to be addressed.

Data on the clinical, functional, and patient-reported outcomes of patient-centred rehabilitation for patients with non-communicable disease living in low-resourced settings.

In this data article, we present data obtained from a randomized clinical trial aimed at determining the feasibility of patient-centred rehabilitation for people with non-communicable disease (NCD) living in a low-resource setting. Patients were identified at primary care level and considered eligible if having on or more of the NCDs central to the NCD burden of disease (Cardiovascular Disease, Diabetes, Pulmonary Disease or Cancer). Using a "trial within cohort" design, a total 74 patients were included (36% of those identified as eligible) in a longitudinal cohort with repeated assessments at baseline, 8 and 16 weeks. A subset of 50 participants were randomly selected and offered to participate in a 6-week exercise and education-based, minimalistic, community-based rehabilitation program tailored to the low-resource context. The exercise component included aerobic and resistance exercise, as well as thematic empowerment aimed at improving exercise self-efficacy. The education component was aimed at improving general health literacy. Data was collected in terms of feasibility parameters (e.g., uptake, adherence), patient-demographics (e.g., age, gender), medical demographics (e.g., disease burden, multimorbidity), functional capacity measures (e.g., 6-minute Walk Test), and patient-reported outcomes (e.g., health-related quality of life). The data presented can give a basis for further clinical research in this field.

High-throughput super-resolution single-particle trajectory analysis reconstructs organelle dynamics and membrane reorganization.

Super-resolution imaging can generate thousands of single-particle trajectories. These data can potentially reconstruct subcellular organization and dynamics, as well as measure disease-linked changes. However, computational methods that can derive quantitative information from such massive datasets are currently lacking. We present data analysis and algorithms that are broadly applicable to reveal local binding and trafficking interactions and organization of dynamic subcellular sites. We applied this analysis to the endoplasmic reticulum and neuronal membrane. The method is based on spatiotemporal segmentation that explores data at multiple levels and detects the architecture and boundaries of high-density regions in areas measuring hundreds of nanometers. By connecting dense regions, we reconstructed the network topology of the endoplasmic reticulum (ER), as well as molecular flow redistribution and the local space explored by trajectories. The presented methods are available as an ImageJ plugin that can be applied to large datasets of overlapping trajectories offering a standard of single-particle trajectory (SPT) metrics.

The Adhesion GPCR VLGR1/ADGRV1 Regulates the Ca2+ Homeostasis at Mitochondria-Associated ER Membranes.

The very large G protein-coupled receptor (VLGR1, ADGRV1) is the largest member of the adhesion GPCR family. Mutations in VLGR1 have been associated with the human Usher syndrome (USH), the most common form of inherited deaf-blindness as well as childhood absence epilepsy. VLGR1 was previously found as membrane-membrane adhesion complexes and focal adhesions. Affinity proteomics revealed that in the interactome of VLGR1, molecules are enriched that are associated with both the ER and mitochondria, as well as mitochondria-associated ER membranes (MAMs), a compartment at the contact sites of both organelles. We confirmed the interaction of VLGR1 with key proteins of MAMs by pull-down assays in vitro complemented by in situ proximity ligation assays in cells. Immunocytochemistry by light and electron microscopy demonstrated the localization of VLGR1 in MAMs. The absence of VLGR1 in tissues and cells derived from VLGR1-deficient mouse models resulted in alterations in the MAM architecture and in the dysregulation of the Ca2+ transient from ER to mitochondria. Our data demonstrate the molecular and functional interaction of VLGR1 with components in MAMs and point to an essential role of VLGR1 in the regulation of Ca2+ homeostasis, one of the key functions of MAMs.

The "trial within cohort design" was a pragmatic model for low-resourced settings.

OBJECTIVES: To determine the feasibility of using a trial within cohort (TWIC) design as a model to study pragmatic interventions in a low-resource setting to ensure that (i) ethical concerns raised with the conventional clinical trial design could be alleviated, (ii) key parameters could be obtained that may promote implementation of interventions in low-resource settings, although retaining the methodological rigor required to assess real-world efficacy. METHODS: A TWIC design was adopted to evaluate the feasibility of a community-based, patient-centered rehabilitation program, in an underprivileged South African community. Procedural aspects of the trial in relation to recruitment, retention, acceptance, and methodological rigor were evaluated. RESULTS: A total of 74 eligible participants, 36% of those who were identified as potential participants, agreed to participate and were randomized. Acceptance of the intervention (56%) was in line with previous research, and no reports of cross-contamination were received. Key lessons were learnt in the conduct of a TWIC design in low-resource settings, among others, related to blinding of the assessor, missing data, timing of recruitment, and various resource constraints. CONCLUSION: The findings of this study support further exploration for the use of this design in low-resource settings, particularly in settings where the conventional randomized clinical trial is ethically challenging or where detailed information on nonacceptance is paramount.

Favorable benefit-risk ratio with teriflunomide treatment in relapsing-remitting multiple sclerosis: Results of the 2-year, multicenter, prospective, noninterventional TAURUS MS study in Austria.

Objectives: A prospective, multicenter, open-label, noninterventional study assessed the efficacy, safety, tolerability, and patient satisfaction with teriflunomide therapy over a 24-month follow-up period under real-world conditions in Austria. Methods: An all-comer population aged ≥18 years was followed in clinic and office-based settings. The primary objective of the study was the annualized relapse rate after 12 and 24 months of teriflunomide treatment. Patient-reported outcomes included treatment satisfaction, health-related quality of life, and fatigue, and were assessed based on the Short Form Health-36, Fatigue Severity Scale, and Treatment Satisfaction Questionnaire for Medication (TSQM)-9 questionnaires. Results: Thirty-one patients were included in the analysis, 23 of whom were still on treatment after 24 months. At 12 months (n = 24), the annualized relapse rate was 0.3 (SD, 0.8), which indicated a significant decrease compared to the annualized relapse rate of 1.0 (SD, 0.9) observed during the 12-month reference period prior to treatment initiation (p = 0.009). Similarly, after 24 months of follow-up (n = 23), the annualized relapse rate of 0.2 (SD, 0.8) was significantly lower than that during the last 24 months reference period prior to treatment initiation of 0.7 (SD, 0.8) (p = 0.0003). The Expanded Disability Status Scale score remained stable over 12 and 24 months. This also applied to patient-reported fatigue of the Fatigue Severity Scale, with a mean change of 0.1 (SD, 1.0). Patient treatment satisfaction as assessed by the TSQM-9 increased for all three domains (i.e., effectiveness, convenience, global satisfaction). This was confirmed by the physician and multiple sclerosis nurse ratings of patient treatment satisfaction and ease of use. Adverse events occurred in 38.7%, with hair thinning and diarrhea as the most common. Conclusions: This noninterventional study showed a sustained favorable benefit-risk ratio for this disease-modifying treatment with teriflunomide over 24 months in patients with relapsing-remitting multiple sclerosis. Patient-reported outcomes and ratings performed by physicians and nurses showed overall trends to improvement for patient treatment satisfaction with teriflunomide treatment and its ease of administration.

Development of the International Cardiac Rehabilitation Registry Including Variable Selection and Definition Process.

Introduction: The International Council of Cardiovascular Prevention and Rehabilitation (ICCPR) is developing a registry (ICRR) specifically for low-resource settings, where the burden of cardiovascular diseases is greatest and the need for program development highest. Herein we describe the development process, including the variable selection process. Method: Following a literature search on registry best practices, a stepwise model for ICRR development was identified. Then, based on recommendations by Core Outcome Set-STAndards for Development (COS-STAD), we underwent a process to identify variables. All available CR registries were contacted to request their data dictionaries, reviewed CR quality indicators and guideline recommendations, and searched for common data elements and core outcome sets; 35 unique variables (including patient-reported outcomes) were selected for potential inclusion. Twenty-one purposively-identified stakeholders and experts agreed to serve on a Delphi panel. Panelists rated the variables in an online survey, and suggested potential additional variables; A webcall was held to reach consensus on which to include/exclude. Next, panelists provided input to finalize each variable definition, and rated which associated indicators should be used for benchmarking in registry dashboards and a patient lay summary; a second consensus call was held. A 1-month public comment period ensued. Results: First, registry objectives and governance were approved by ICCPR, including data quality and access policies. The protocol was developed, for public posting. For variable selection, the overall mean rating was 6.1 ± 0.3/7; 12 were excluded, some of which were moved to a program survey, and others were revised. Two variables were added in an annual follow-up, resulting in 13 program and 16 patient-reported variables. Legal advice was sought to finalize ICRR agreements. Ethics approvals were obtained. Usability testing is now being initiated. Conclusion: It is hoped this will serve to harmonize CR assessment internationally and enable quality improvement in CR delivery in low-resource settings.

A modified six-minute walk test (6MWT) for low-resource settings-a cross-sectional study.

BACKGROUND: The 6 min walk test (6MWT) is a validated tool used to assess functional capacity in a variety of patient populations. Space constraints often limit the practicality of the 6MWT according to the standard (2002) American Thoracic Society protocol, and therefore, adaptations to this protocol are common with potential implications for research and clinical practice. Furthermore, such implications for research and clinical practice may be augmented in low-resourced settings. OBJECTIVES: To determine the agreement between the 6 min walk distance (6MWD) achieved on the standard 30 m (6MWT30), and a straight 10 m (6MWT10), or 10 m figure-of-eight (6MWTF8) configuration, respectively. METHODS: A cross-sectional study was conducted in a socioeconomic challenged community. A heterogeneous sample of adults (n = 27) with non-communicable disease were randomized into performing the 6MWT10 (n = 15) or 6MWTF8 (n = 12), in addition to the standard 6MWT30. Pairwise comparison and concordance correlation coefficients were used to assess agreement. RESULTS: The mean (SD) 6MWD30 was 437(42) meters, while the mean 6MWD10 was 371(57). The mean difference (SE; p-value) between the 6MWD30 and 6MWD10 was 67 m (8.6; p .01). The mean 6MWD30 was 424(67) meters, while the mean 6MWDF8 was 347(58). The mean difference between the 6MWD30 and 6MWDF8 was 77 m (6.0; p .01). Moderate concordance was found between the 6MWT30 and 6MWTF8 or 6MWD10, respectively. CONCLUSIONS: The present data suggest that, independent of configuration, using a shorter pathway significantly reduced the 6MWD. Low-resource settings may benefit from contemporary measures of functional capacity more conducive to resource constraints, or standardization of the test when used in such settings.

Developing a Complex Understanding of Physical Activity in Cardiometabolic Disease from Low-to-Middle-Income Countries-A Qualitative Systematic Review with Meta-Synthesis.

Physical activity behaviour is complex, particularly in low-resource settings, while existing behavioural models of physical activity behaviour are often linear and deterministic. The objective of this review was to (i) synthesise the wide scope of factors that affect physical activity and thereby (ii) underpin the complexity of physical activity in low-resource settings through a qualitative meta-synthesis of studies conducted among patients with cardiometabolic disease living in low-to-middle income countries (LMIC). A total of 41 studies were included from 1200 unique citations (up to 15 March 2021). Using a hybrid form of content analysis, unique factors (n = 208) that inform physical activity were identified, and, through qualitative meta-synthesis, these codes were aggregated into categories (n = 61) and synthesised findings (n = 26). An additional five findings were added through deliberation within the review team. Collectively, the 31 synthesised findings highlight the complexity of physical activity behaviour, and the connectedness between person, social context, healthcare system, and built and natural environment. Existing behavioural and ecological models are inadequate in fully understanding physical activity participation in patients with cardiometabolic disease living in LMIC. Future research, building on complexity science and systems thinking, is needed to identify key mechanisms of action applicable to the local context.

Separation of presynaptic Cav2 and Cav1 channel function in synaptic vesicle exo- and endocytosis by the membrane anchored Ca2+ pump PMCA.

Synaptic vesicle (SV) release, recycling, and plastic changes of release probability co-occur side by side within nerve terminals and rely on local Ca2+ signals with different temporal and spatial profiles. The mechanisms that guarantee separate regulation of these vital presynaptic functions during action potential (AP)-triggered presynaptic Ca2+ entry remain unclear. Combining Drosophila genetics with electrophysiology and imaging reveals the localization of two different voltage-gated calcium channels at the presynaptic terminals of glutamatergic neuromuscular synapses (the Drosophila Cav2 homolog, Dmca1A or cacophony, and the Cav1 homolog, Dmca1D) but with spatial and functional separation. Cav2 within active zones is required for AP-triggered neurotransmitter release. By contrast, Cav1 localizes predominantly around active zones and contributes substantially to AP-evoked Ca2+ influx but has a small impact on release. Instead, L-type calcium currents through Cav1 fine-tune short-term plasticity and facilitate SV recycling. Separate control of SV exo- and endocytosis by AP-triggered presynaptic Ca2+ influx through different channels demands efficient measures to protect the neurotransmitter release machinery against Cav1-mediated Ca2+ influx. We show that the plasma membrane Ca2+ ATPase (PMCA) resides in between active zones and isolates Cav2-triggered release from Cav1-mediated dynamic regulation of recycling and short-term plasticity, two processes which Cav2 may also contribute to. As L-type Cav1 channels also localize next to PQ-type Cav2 channels within axon terminals of some central mammalian synapses, we propose that Cav2, Cav1, and PMCA act as a conserved functional triad that enables separate control of SV release and recycling rates in presynaptic terminals.

Six-minute walk test protocol variations in low-resource settings - A scoping review.

BACKGROUND: The 6-min walk test (6MWT) is a validated tool, of submaximal intensity, used to objectively measure functional exercise capacity. In 2002, the American Thoracic Society (ATS) developed guidelines on standardising the implementation of the 6MWT. Despite the relative ease of conducting the 6MWT as per these guidelines, adaptations are implemented. OBJECTIVES: Identify (1) what 6MWT adaptations to the ATS guidelines have been described in low-resource settings (LRS), (2) the purpose of the adapted 6MWT and (3) the reported argumentation for making these adaptations in relation to the specific context. METHODS: Five databases were searched from inception until February 2021. Studies that adapted and conducted the 6MWT in LRS were included. Data concerning the study source, participants, 6MWT: purpose, variations, outcome and rationale were extracted. RESULTS: A total of 24 studies were included. The majority of studies (n = 18; 75%) were conducted in lower-middle income countries. The most common adaptation implemented was variation to course length. Eight studies provided a rationale for adapting the 6MWT. Space constraint was the most common reason for adaptation. CONCLUSION: The most common reason (space constraints) for adapting the 6MWT in LRS was addressed through adaptations in course length and/or configuration. The results of this review suggest that the value of the ATS-guided 6MWT in LRS may need to be re-evaluated. CLINICAL IMPLICATIONS: Using adapted forms of the 6MWT may lead to an underestimation of a patient's abilities, misinformed discharge and developing inappropriate exercise programmes. Additionally, diverting from ATS guidelines may affect the continuity of care.

More than a pore: How voltage-gated calcium channels act on different levels of neuronal communication regulation.

Voltage-gated calcium channels (VGCCs) represent key regulators of the calcium influx through the plasma membrane of excitable cells, like neurons. Activated by the depolarization of the membrane, the opening of VGCCs induces very transient and local changes in the intracellular calcium concentration, known as calcium nanodomains, that in turn trigger calcium-dependent signaling cascades and the release of chemical neurotransmitters. Based on their central importance as concierges of excitation-secretion coupling and therefore neuronal communication, VGCCs have been studied in multiple aspects of neuronal function and malfunction. However, studies on molecular interaction partners and recent progress in omics technologies have extended the actual concept of these molecules. With this review, we want to illustrate some new perspectives of VGCCs reaching beyond their function as calcium-permeable pores in the plasma membrane. Therefore, we will discuss the relevance of VGCCs as voltage sensors in functional complexes with ryanodine receptors, channel-independent actions of auxiliary VGCC subunits, and provide an insight into how VGCCs even directly participate in gene regulation. Furthermore, we will illustrate how structural changes in the intracellular C-terminus of VGCCs generated by alternative splicing events might not only affect the biophysical channel characteristics but rather determine their molecular environment and downstream signaling pathways.

Unravelling 'low-resource settings': a systematic scoping review with qualitative content analysis.

INTRODUCTION: The effects of healthcare-related inequalities are most evident in low-resource settings. Such settings are often not explicitly defined, and umbrella terms which are easier to operationalise, such as 'low-to-middle-income countries' or 'developing countries', are often used. Without a deeper understanding of context, such proxies are pregnant with assumptions, insinuate homogeneity that is unsupported and hamper knowledge translation between settings. METHODS: A systematic scoping review was undertaken to start unravelling the term 'low-resource setting'. PubMed, Africa-Wide, Web of Science and Scopus were searched (24 June 2019), dating back ≤5 years, using terms related to 'low-resource setting' and 'rehabilitation'. Rehabilitation was chosen as a methodological vehicle due to its holistic nature (eg, multidisciplinary, relevance across burden of disease, and throughout continuum of care) and expertise within the research team. Qualitative content analysis through an inductive approach was used. RESULTS: A total of 410 codes were derived from 48 unique articles within the field of rehabilitation, grouped into 63 content categories, and identified nine major themes relating to the term 'low-resource setting'. Themes that emerged relate to (1) financial pressure, (2) suboptimal healthcare service delivery, (3) underdeveloped infrastructure, (4) paucity of knowledge, (5) research challenges and considerations, (6) restricted social resources, (7) geographical and environmental factors, (8) human resource limitations and (9) the influence of beliefs and practices. CONCLUSION: The emerging themes may assist with (1) the groundwork needed to unravel 'low-resource settings' in health-related research, (2) moving away from assumptive umbrella terms like 'low-to-middle-income countries' or 'low/middle-income countries' and (3) promoting effective knowledge transfer between settings.

Patient-Reported OUtcome measures in key African languages to promote Diversity in research and clinical practice (PROUD)-protocol for a systematic review of measurement properties.

INTRODUCTION: Sub-Saharan Africa is a subcontinent with a proud cultural richness and diversity, yet inexplicably also a region with severe health care challenges and inequity. To challenge this health equity gap and reduce the burden of disease, the patient's voice in monitoring and evaluation of health and health care interventions is paramount. The aim of this two-phased review is to map the availability of patient-reported outcome measures (PROMs) in a selection of non-English, African Languages, and systematically evaluate the measurement properties of the PROMs that were identified. METHODS: This systematic review will be conducted in two phases. In phase 1, we will scope the literature for patient-reported outcome measures (PROMs), either developed from scratch or through translation and validation in a sub-Saharan African country and a selection of non-English, African languages (n = 31; spoken in > 10 million people and/or a national language). The availability of PROMs will be mapped against the previously reported burden of disease in the respective countries included. Subsequently, in phase 2, we systematically evaluate the measurement properties of these PROMs using the COnsensus-based Standards for the selection of health Measurement INstruments (COSMIN) methodology for systematic reviews on PROMs. To ensure rigour, secondary searches will be developed to specifically locate articles that report on the measurement properties of the PROMs identified during phase 1. The evidence will be graded using the modified GRADE approach. DISCUSSION: This review will provide a comprehensive overview and quality appraisal of PROMs developed in non-English, African languages. Consequently, this review when concluded may be an important first step in promoting access to these PROMs for use in clinical practice and research, as well as facilitate identification and prioritization of key knowledge gaps.

Endogenous ß-neurexins on axons and within synapses show regulated dynamic behavior.

Neurexins are key organizer molecules that regulate synaptic function and are implicated in autism and schizophrenia. ß-neurexins interact with numerous cell adhesion and receptor molecules, but their neuronal localization remains elusive. Using single-molecule tracking and high-resolution microscopy to detect neurexin1ß and neurexin3ß in primary hippocampal neurons from knockin mice, we demonstrate that endogenous ß-neurexins are present in fewer than half of excitatory and inhibitory synapses. Moreover, we observe a large extrasynaptic pool of ß-neurexins on axons and show that axonal ß-neurexins diffuse with higher surface mobility than those transiently confined within synapses. Stimulation of neuronal activity further increases the mobility of synaptic and axonal ß-neurexins, whereas inhibition causes the opposite. Blocking ectodomain cleavage by metalloproteases also reduces ß-neurexin mobility and enhances glutamate release. These findings suggest that the surface mobility of endogenous ß-neurexins inside and outside of synapses is dynamically regulated and linked to neuronal activity.