Let it go: mechanisms that detach myosin V from the yeast vacuole.

A major question in cell biology is, how are organelles and macromolecular machines moved within a cell? The delivery of cargoes to the right place at the right time within a cell is critical to cellular health. Failure to do so is often catastrophic for animal physiology and results in diseases of the gut, brain, and skin. In budding yeast, a myosin V motor, Myo2, moves cellular materials from the mother cell into the growing daughter bud. Myo2-based transport ensures that cellular contents are shared during cell division. During transport, Myo2 is often linked to its cargo via cargo-specific adaptor proteins. This simple organism thus serves as a powerful tool to study how myosin V moves cargo, such as organelles. Some critical questions include how myosin V moves along the actin cytoskeleton, or how myosin V attaches to cargo in the mother. Other critical questions include how the cargo is released from myosin V when it reaches its final destination in the bud. Here, we review the mechanisms that regulate the vacuole-specific adaptor protein, Vac17, to ensure that Myo2 delivers the vacuole to the bud and releases it at the right place and the right time. Recent studies have revealed that Vac17 is regulated by ubiquitylation and phosphorylation events that coordinate its degradation and the detachment of the vacuole from Myo2. Thus, multiple post-translational modifications tightly coordinate cargo delivery with cellular events. It is tempting to speculate that similar mechanisms regulate other cargoes and molecular motors.

Older Adults With Subjective Cognitive Decline Worry About the Emotional Impact of Cognitive Test Results.

INTRODUCTION: Older adults with subjective cognitive decline (SCD) would benefit from routine cognitive testing as they are twice as likely to develop dementia. Worries about concerning test results may diminish participation. The current study aimed to characterize the pattern of worries among older adults with and without SCD. METHODS: Adults 50 years or above completed the Attitudes Around Cognitive Testing questionnaire on Mechanical Turk.com or in a primary care setting. Mechanical Turk.com is an online crowdsourcing site where requesters (eg, researchers) post jobs (eg, surveys or tasks) and workers (eg, respondents) choose which jobs to do for pay. Respondents were asked about perceived cognitive decline and about different types of worries they anticipated having if they received concerning test results. RESULTS: We report data for 393 respondents (online: n=296, primary care: n=97), mean age of 63 years, age range of 50 to 91 years, and 60% endorsing SCD. Compared with No SCD, those with SCD anticipated a higher number of worries centered disproportionately on worries of becoming depressed, ashamed or embarrassed, feeling "stupid" and unable to do things, and being put in a nursing home. We observed this SCD pattern of worries in both samples. DISCUSSION: Individuals with SCD worry about the emotional consequences of cognitive testing. This at-risk group would benefit from interventions focused on these concerns to increase patient engagement with cognitive tests.

Mitochondrial-derived compartments remove surplus proteins from the outer mitochondrial membrane.

The outer mitochondrial membrane (OMM) creates a boundary that imports most of the mitochondrial proteome while removing extraneous or damaged proteins. How the OMM senses aberrant proteins and remodels to maintain OMM integrity remains unresolved. Previously, we identified a mitochondrial remodeling mechanism called the mitochondrial-derived compartment (MDC) that removes a subset of the mitochondrial proteome. Here, we show that MDCs specifically sequester proteins localized only at the OMM, providing an explanation for how select mitochondrial proteins are incorporated into MDCs. Remarkably, selective sorting into MDCs also occurs within the OMM, as subunits of the translocase of the outer membrane (TOM) complex are excluded from MDCs unless assembly of the TOM complex is impaired. Considering that overloading the OMM with mitochondrial membrane proteins or mistargeted tail-anchored membrane proteins induces MDCs to form and sequester these proteins, we propose that one functional role of MDCs is to create an OMM-enriched trap that segregates and sequesters excess proteins from the mitochondrial surface.

A REM-active basal ganglia circuit that regulates anxiety.

Rapid eye movement (REM) sleep has been hypothesized to promote emotional resilience, but any neuronal circuits mediating this have not been identified. We find that in mice, somatostatin (Som) neurons in the entopeduncular nucleus (EPSom)/internal globus pallidus are predominantly active during REM sleep. This unique REM activity is both necessary and sufficient for maintaining normal REM sleep. Inhibiting or exciting EPSom neurons reduced or increased REM sleep duration, respectively. Activation of the sole downstream target of EPSom neurons, Vglut2 cells in the lateral habenula (LHb), increased sleep via the ventral tegmental area (VTA). A simple chemogenetic scheme to periodically inhibit the LHb over 4 days selectively removed a significant amount of cumulative REM sleep. Chronic, but not acute, REM reduction correlated with mice becoming anxious and more sensitive to aversive stimuli. Therefore, we suggest that cumulative REM sleep, in part generated by the EP → LHb → VTA circuit identified here, could contribute to stabilizing reactions to habitual aversive stimuli.

Describing adolescents with disabilities' experiences of COVID-19 and other humanitarian emergencies in low- and middle-income countries: a scoping review.

BACKGROUND: The COVID-19 pandemic and other humanitarian emergencies exacerbate pre-existing inequalities faced by people with disabilities. They experience worse access to health, education, and social services, and increased violence in comparison with people without disabilities. Adolescents with disabilities are amongst those most severely affected in these situations. Using participatory research methods with adolescents can be more effective than other methods but may be challenging in such emergency contexts. OBJECTIVES: We conducted a scoping review to: 1) describe the literature and methods used in peer-reviewed and grey literature on adolescents (aged ten to nineteen) with disabilities' experience of COVID-19 and other humanitarian emergencies in low- and middle-income countries, and 2) identify research gaps and make recommendations for future research. METHODS: The review followed a protocol developed using PRISMA guidelines and the Arksey and O'Malley framework. We searched grey and peer-reviewed literature between 2011 and 2021. RESULTS: Thirty studies were included. Twelve were peer-reviewed, and of those seven used participatory methods. Humanitarian emergencies had adverse effects on adolescents with disabilities across health, education, livelihoods, social protection, and community participation domains. Surprisingly few studies collected data directly with adolescents with disabilities. Twenty-three studies combined data from non-disabled children, caregivers, and disabled adults which made it challenging to understand adolescents with disabilities' unique experience. CONCLUSIONS: Our review highlights both the scarcity of literature and the importance of conducting research with adolescents with disabilities in humanitarian contexts. Despite challenges, our review shows that it has been possible to conduct research with adolescents with disabilities to explore their experiences of humanitarian emergencies, and that these experiences were different from those of non-disabled adolescents. There is a need to disaggregate findings and support the implementation and reporting of rigorous research methods. Capacity development through partnerships between non-governmental organisations and researchers may improve reporting of methods.

Socioeconomic Status and Nutritional Status as Predictors of Food Insecurity in Older Adults: A Case Study from Southern Ecuador.

While life expectancy is increasing due to scientific advancement, quality of life in aging depends, among other factors, on the nutritional status and socioeconomic status of older adults. To determine socioeconomic status and its association with nutritional status as a predictor of food insecurity among older adults in southern Ecuador, a cross-sectional study of 188 older adults in urban areas and 212 in rural areas was conducted. Nutritional status, food insecurity, and socioeconomic status were measured. Data were analyzed using SPSS v 15.0 for descriptive statistics and bivariate analysis. Of the older participants, 59% had malnutrition, the majority women, and 24.7% were in poverty. Underweight was associated with low socioeconomic status for adults between 65 and 74 years old (OR = 7.710; CI 95% = 1.691-35.147), while obesity was associated with low socioeconomic status and non-manual labor (OR = 3.048; CI 95% = 1.268-7.326). Over 80% of older adults living in homes without children younger than 18 and at low socioeconomic status had food insecurity. The prevalence of underweight, overweight, and obesity points to widespread nutritional problems, especially in rural areas, that are significantly associated with low socioeconomic status. This demonstrates the need for multidisciplinary programs and government policies that can contribute to reducing food insecurity among the highly vulnerable older population.

Roles and regulation of myosin V interaction with cargo.

A major question in cell biology is, how are organelles and large macromolecular complexes transported within a cell? Myosin V molecular motors play critical roles in the distribution of organelles, vesicles, and mRNA. Mis-localization of organelles that depend on myosin V motors underlie diseases in the skin, gut, and brain. Thus, the delivery of organelles to their proper destination is important for animal physiology and cellular function. Cargoes attach to myosin V motors via cargo specific adaptor proteins, which transiently bridge motors to their cargoes. Regulation of these adaptor proteins play key roles in the regulation of cargo transport. Emerging studies reveal that cargo adaptors play additional essential roles in the activation of myosin V, and the regulation of actin filaments. Here, we review how motor-adaptor interactions are controlled to regulate the proper loading and unloading of cargoes, as well as roles of adaptor proteins in the regulation of myosin V activity and the dynamics of actin filaments.

Cargo Release from Myosin V Requires the Convergence of Parallel Pathways that Phosphorylate and Ubiquitylate the Cargo Adaptor.

Cellular function requires molecular motors to transport cargoes to their correct intracellular locations. The regulated assembly and disassembly of motor-adaptor complexes ensures that cargoes are loaded at their origin and unloaded at their destination. In Saccharomyces cerevisiae, early in the cell cycle, a portion of the vacuole is transported into the emerging bud. This transport requires a myosin V motor, Myo2, which attaches to the vacuole via Vac17, the vacuole-specific adaptor protein. Vac17 also binds to Vac8, a vacuolar membrane protein. Once the vacuole is brought to the bud cortex via the Myo2-Vac17-Vac8 complex, Vac17 is degraded and the vacuole is released from Myo2. However, mechanisms governing dissociation of the Myo2-Vac17-Vac8 complex are not well understood. Ubiquitylation of the Vac17 adaptor at the bud cortex provides spatial regulation of vacuole release. Here, we report that ubiquitylation alone is not sufficient for cargo release. We find that a parallel pathway, which initiates on the vacuole, converges with ubiquitylation to release the vacuole from Myo2. Specifically, we show that Yck3 and Vps41, independent of their known roles in homotypic fusion and protein sorting (HOPS)-mediated vesicle tethering, are required for the phosphorylation of Vac17 in its Myo2 binding domain. These phosphorylation events allow ubiquitylated Vac17 to be released from Myo2 and Vac8. Our data suggest that Vps41 is regulating the phosphorylation of Vac17 via Yck3, a casein kinase I, and likely another unknown kinase. That parallel pathways are required to release the vacuole from Myo2 suggests that multiple signals are integrated to terminate organelle inheritance.

Optimized fasting and OGTT-based simple surrogate methods for assessing insulin sensitivity.

AIMS: Simple surrogate indices of insulin sensitivity have been conceived to deal with costly and complicated approaches, such as the hyperinsulinemic-euglycemic clamp; however, their use has not been widespread given their variabilities in different populations. In this paper, we present two simple surrogate indices, one that uses fasting glucose and insulin values and the other based on the values from the oral glucose tolerance test. MATERIALS AND METHODS: The proposed methods integrate easy-to-obtain anthropometric measures. Evolutionary algorithms were used to optimize the proposed methods by maximizing its correlation with the Stumvoll MCR method. RESULTS AND CONCLUSION: When the proposed indices were applied to three study groups (control subjects, metabolic syndrome, marathon runners), a reduction in the intergroup variability of the insulin sensitivity was obtained. Moreover, the proposed index based on the oral glucose tolerance test (OGTT), which considers the glucose metabolism process and the hepatic and peripheral insulin sensitivity, showed stronger correlations with the Stumvoll method and lower intergroup variability than the fasting one.

Cardiac autonomic modulation in response to a glucose stimulus.

This paper focuses on the effect of a sudden increase of plasma glucose concentration in the cardiac autonomic modulation using time-domain and frequency-domain heart rate variability (HRV) measures. Plasma glucose and insulin levels, measured each 30 min during an oral glucose tolerance test, and [Formula: see text] (mean of the RR interval), SDNN (standard deviation of normal-to-normal heartbeats), rMSSD (root-mean-square of successive differences between normal heartbeats), TP (total spectral power), LF and HF (power of the low- and high-frequency bands), LF norm and HF norm (LF and HF in normalized units), and LF/HF ratio of the HRV signal, obtained from 5-min-long ECG recordings during each phase of the test, were analyzed for subjects with the metabolic syndrome, marathon runners, and a control group. Results show that, after the glucose load, subjects with the metabolic syndrome experienced an increased sympathetic and decreased parasympathetic tone, which suggests an imbalance in cardiac autonomic modulation as a consequence of hyperglycemia and hyperinsulinemia. The significance of this study lies in the use of the ECG to assess the effects of a sudden increase in plasma glucose concentration on the cardiac autonomic modulation in subjects with different cardiovascular and metabolic conditions. Graphical Abstract Time-domain and frequency-domain heart rate variability measures are altered in subjects with different cardiovascular and metabolic conditions during an oral glucose tolerance test.

ECG Multilead QT Interval Estimation Using Support Vector Machines.

This work reports a multilead QT interval measurement algorithm for a high-resolution digital electrocardiograph. The software enables off-line ECG processing including QRS detection as well as an accurate multilead QT interval detection algorithm using support vector machines (SVMs). Two fiducial points (Q ini and T end) are estimated using the SVM algorithm on each incoming beat. This enables segmentation of the current beat for obtaining the P, QRS, and T waves. The QT interval is estimated by updating the QT interval on each lead, considering shifting techniques with respect to a valid beat template. The validation of the QT interval measurement algorithm is attained using the Physionet PTB diagnostic ECG database showing a percent error of 2.60 ± 2.25 msec with respect to the database annotations. The usefulness of this software tool is also tested by considering the analysis of the ECG signals for a group of 60 patients acquired using our digital electrocardiograph. In this case, the validation is performed by comparing the estimated QT interval with respect to the estimation obtained using the Cardiosoft software providing a percent error of 2.49 ± 1.99 msec.

Older Adults' Attitudes towards Cognitive Testing: Moving towards Person-Centeredness.

BACKGROUND: Research on person-centered cognitive testing is beginning to emerge. The current study is the first to focus on eliciting concrete preferences around the test experience. METHODS: Adults ≥50 years old completed the Attitudes Around Cognitive Testing (AACT) questionnaire on mturk.com. AACT elicits preferences for cognitive tests, the importance attributed to having choices, and willingness to engage in testing. RESULTS: Data are reported for 289 respondents. The proportion of participants expressing preferences varied by domain (modality [49.5%], location [47.2%], company [80.1%], result delivery [78.3-89.7%]). Importance ratings for all domains had a median of 4 and a range of 1-5 using a Likert scale of agreement. Most participants (85.5%) were willing to engage in testing. CONCLUSION: Older adults have preferences for cognitive tests, especially with delivery of results.

Spatial regulation of organelle release from myosin V transport by p21-activated kinases.

Correct positioning of organelles is essential to eukaryotic cells. Molecular motors transport organelles to their proper destinations, yet little is known about the pathways that define these destinations. In Saccharomyces cerevisiae, the myosin V motor Myo2 binds the vacuole-specific adapter Vac17 to attach to the vacuole/lysosome and initiate transport. After arrival in the bud, Myo2 releases the vacuole, and Vac17 is degraded. However, the mechanisms that spatially regulate this release were not established. In this study, we report that the bud cortex is a landmark that signals a successful delivery of the vacuole to the bud. We demonstrate that upon arrival at the bud cortex, Vac17 is phosphorylated by Cla4. Cla4-dependent phosphorylation is required for the ubiquitylation and subsequent degradation of Vac17 and the release of the vacuole from Myo2. Our study reveals a critical step in the spatial regulation of myosin V-dependent organelle transport and may reveal common mechanisms for how molecular motors accurately deposit cargoes at the correct locations.

Hyperpolarization-activated cyclic nucleotide-gated 2 (HCN2) ion channels drive pain in mouse models of diabetic neuropathy.

Diabetic patients frequently suffer from continuous pain that is poorly treated by currently available analgesics. We used mouse models of type 1 and type 2 diabetes to investigate a possible role for the hyperpolarization-activated cyclic nucleotide-gated 2 (HCN2) ion channels as drivers of diabetic pain. Blocking or genetically deleting HCN2 channels in small nociceptive neurons suppressed diabetes-associated mechanical allodynia and prevented neuronal activation of second-order neurons in the spinal cord in mice. In addition, we found that intracellular cyclic adenosine monophosphate (cAMP), a positive HCN2 modulator, is increased in somatosensory neurons in an animal model of painful diabetes. We propose that the increased intracellular cAMP drives diabetes-associated pain by facilitating HCN2 activation and consequently promoting repetitive firing in primary nociceptive nerve fibers. Our results suggest that HCN2 may be an analgesic target in the treatment of painful diabetic neuropathy.

[Metabolic syndrome and physical activity in elderly people from the Ecuadorian highlands]. / Síndrome metabólico y actividad física en adultos mayores de la sierra ecuatoriana.

OBJECTIVE: Determine the prevalence of the metabolic syndrome, the level of physical activity and the association with these factors in the elderly from the Ecuadorian highlands. METHODS: Cross-sectional study that evaluated 387 older adults from Cuenca-Ecuador, who wished to participate and signed the informed consent. The diagnosis of metabolic syndrome was made using the criteria of the National Program of Education on Cholesterol and the Adult Treatment Panel III, for the value of Abdominal Circumference the criteria used for the Asian population was considered. The level of physical activity was evaluated by the short version of the International Physical Activity Questionnaire. The groups with and without metabolic syndrome were compared using the chi-square test and student's t-test. The analysis of variance was used to evaluate the association between the components of the metabolic syndrome and the level of physical activity. RESULTS: The prevalence of metabolic syndrome was high (59.9 %), as well as the high level of physical activity (45 %), however, there was no significant association between the metabolic syndrome and physical activity level. CONCLUSIONS: Older adults diagnosed with metabolic syndrome presented the same level of physical activity as individuals without this diagnosis. It is necessary to confirm the present findings using direct measurement instruments of physical activity.

OBJETIVO: Determinar la prevalencia del síndrome metabólico, el nivel de actividad física y la asociación de estos factores en los adultos mayores de la sierra ecuatoriana. MÉTODOS: Estudio transversal que evaluó 387 adultos mayores de Cuenca-Ecuador, quienes desearon participar y firmaron el consentimiento informado. El diagnóstico de síndrome metabólico se realizó mediante los criterios del Programa Nacional de Educación sobre el Colesterol y el Panel de Tratamiento del Adulto III, para el valor de la Circunferencia Abdominal se consideró los criterios usados para la población asiática. El nivel de actividad física fue evaluado por la versión corta del Cuestionario Internacional de Actividad Física. Se compararon los grupos con y sin síndrome metabólico mediante el test Chi-cuadrado y el test t de student. El análisis de variancia fue usado para evaluar la asociación entre los componentes del síndrome metabólico y el nivel de actividad física. RESULTADOS: La prevalencia de síndrome metabólico fue alta (59,9 %), así como el nivel alto de actividad física (45 %), sin embargo no se evidenció asociación significativa entre el síndrome metabólico y nivel de actividad física. CONCLUSIÓN: Los adultos mayores diagnosticados con síndrome metabólico presentaron el mismo nivel de actividad física que los individuos sin este diagnóstico. Es necesario confirmar los presentes hallazgos usando instrumentos de medición directa de actividad física.

A Non-Cell-Autonomous Role of BEC-1/BECN1/Beclin1 in Coordinating Cell-Cycle Progression and Stem Cell Proliferation during Germline Development.

The decision of stem cells to proliferate and differentiate is finely controlled. The Caenorhabditis elegans germline provides a tractable system for studying the mechanisms that control stem cell proliferation and homeostasis [1-4]. Autophagy is a conserved cellular recycling process crucial for cellular homeostasis in many different contexts [5], but its function in germline stem cell proliferation remains poorly understood. Here, we describe a function for autophagy in germline stem cell proliferation. We found that autophagy genes such as bec-1/BECN1/Beclin1, atg-16.2/ATG16L, atg-18/WIPI1/2, and atg-7/ATG7 are required for the late larval expansion of germline stem cell progenitors in the C. elegans gonad. We further show that BEC-1/BECN1/Beclin1 acts independently of the GLP-1/Notch or DAF-7/TGF-ß pathways but together with the DAF-2/insulin IGF-1 receptor (IIR) signaling pathway to promote germline stem cell proliferation. Similar to DAF-2/IIR, BEC-1/BECN1/Beclin1, ATG-18/WIPI1/2, and ATG-16.2/ATG16L all promote cell-cycle progression and are negatively regulated by the phosphatase and tensin homolog DAF-18/PTEN. However, whereas BEC-1/BECN1/Beclin1 acts through the transcriptional regulator SKN-1/Nrf1, ATG-18/WIPI1/2 and ATG-16.2/ATG16L exert their function through the DAF-16/FOXO transcription factor. In contrast, ATG-7 functions in concert with the DAF-7/TGF-ß pathway to promote germline proliferation and is not required for cell-cycle progression. Finally, we report that BEC-1/BECN1/Beclin1 functions non-cell-autonomously to facilitate cell-cycle progression and stem cell proliferation. Our findings demonstrate a novel non-autonomous role for BEC-1/BECN1/Beclin1 in the control of stem cell proliferation and cell-cycle progression, which may have implications for the understanding and development of therapies against malignant cell growth in the future.

Comparing glucose and insulin data from the two-hour oral glucose tolerance test in metabolic syndrome subjects and marathon runners.

Glucose is the main energy source of the body's cells and is essential for normal metabolism. Two pancreatic hormones, insulin and glucagon, are involved in glucose home-ostasis. Alteration in the plasma glucose and insulin concentrations could lead to distinct symptoms and diseases, ranging from mental function impairment to coma and even death. Type 2 diabetes, insulin resistance and metabolic syndrome are typical examples of abnormal glucose metabolism that increase the risk for cardiovascular disease and mortality. The oral glucose tolerance test (OGTT) is a medical test used to screen for prediabetes, type 2 diabetes and insulin resistance. In the 5-sample 2-hour OGTT, plasma glucose and insulin concentrations are measured after a fast and then after oral intake of glucose, at intervals of 30 minutes. In this work, a statistical analysis is carried out to find significant differences between the five stages of the OGTT for plasma glucose and insulin data. In addition, the behavior of the glucose and insulin data is compared between subjects with the metabolic syndrome and marathon runners. Results show that marathon runners have plasma glucose and insulin levels significantly lower (p <; 0.05) than people with the metabolic syndrome in all the stages of the OGTT. Insulin secretion decreases in marathon runners due to a significant reduction in plasma glucose concentration, but insulin secretion does not decrease in metabolic syndrome subjects due to insulin resistance, consequently plasma glucose concentration does not achieve normal levels.

Characterizing artifacts in RR stress test time series.

Electrocardiographic stress test records have a lot of artifacts. In this paper we explore a simple method to characterize the amount of artifacts present in unprocessed RR stress test time series. Four time series classes were defined: Very good lead, Good lead, Low quality lead and Useless lead. 65 ECG, 8 lead, records of stress test series were analyzed. Firstly, RR-time series were annotated by two experts. The automatic methodology is based on dividing the RR-time series in non-overlapping windows. Each window is marked as noisy whenever it exceeds an established standard deviation threshold (SDT). Series are classified according to the percentage of windows that exceeds a given value, based upon the first manual annotation. Different SDT were explored. Results show that SDT close to 20% (as a percentage of the mean) provides the best results. The coincidence between annotators classification is 70.77% whereas, the coincidence between the second annotator and the automatic method providing the best matches is larger than 63%. Leads classified as Very good leads and Good leads could be combined to improve automatic heartbeat labeling.

Anthropometric measurements for assessing insulin sensitivity on patients with metabolic syndrome, sedentaries and marathoners.

The diagnosis of low insulin sensitivity is commonly done through the HOMA-IR index, in which fasting insulin and glucose blood levels are evaluated. Insulin and blood glucose levels are used for insulin sensitivity assessment by surrogate methods (HOMA-IR, Matsuda, etc), but anthropometric measurements like body weight, height and waist circumference are not considered, even if these variables also are related to low insulin sensitivity and metabolic syndrome. In this study we evaluate the impact of anthropometric measurements on the HOMA-IR, Matsuda and Caumo indexes to estimate insulin sensitivity. Specifically, we compare insulin sensitivity indexes with and without the anthropometric measurements in their equations on three different groups: patients with metabolic syndrome, sedentaries and marathoners. Results show relationships between anthropometric variables and insulin sensitivity indexes. On the other hand, subjects are mapped differently for insulin sensitivity assessment when anthropometric variables are taken into account. In addition, subjects diagnosed with normal insulin sensitivity could be considered as having low insulin sensitivity when anthropometric variables are considered.