Loss of TDP-43 induces synaptic dysfunction that is rescued by UNC13A splice-switching ASOs.

TDP-43 loss of function induces multiple splicing changes, including a cryptic exon in the amyotrophic lateral sclerosis and fronto-temporal lobar degeneration risk gene UNC13A, leading to nonsense-mediated decay of UNC13A transcripts and loss of protein. UNC13A is an active zone protein with an integral role in coordinating pre-synaptic function. Here, we show TDP-43 depletion induces a severe reduction in synaptic transmission, leading to an asynchronous pattern of network activity. We demonstrate that these deficits are largely driven by a single cryptic exon in UNC13A. Antisense oligonucleotides targeting the UNC13A cryptic exon robustly rescue UNC13A protein levels and restore normal synaptic function, providing a potential new therapeutic approach for ALS and other TDP-43-related disorders.

Excitatory and inhibitory synapses show a tight subcellular correlation that weakens over development.

Neurons receive correlated levels of excitation and inhibition, a feature that is important for proper brain function. However, how this relationship between excitatory and inhibitory inputs is established during the dynamic period of circuit wiring remains unexplored. Using multiple techniques, including in utero electroporation, electron microscopy, and electrophysiology, we reveal a tight correlation in the distribution of excitatory and inhibitory synapses along the dendrites of developing CA1 hippocampal neurons. This correlation was present within short dendritic stretches (<20 µm) and, surprisingly, was most pronounced during early development, sharply declining with maturity. The tight matching between excitation and inhibition was unexpected, as inhibitory synapses lacked an active zone when formed and exhibited compromised evoked release. We propose that inhibitory synapses form as a stabilizing scaffold to counterbalance growing excitation levels. This relationship diminishes over time, suggesting a critical role for a subcellular balance in early neuronal function and circuit formation.

Cultural adaption, translation, preliminary reliability and validity of psychological and behavioural measures for adolescents living with HIV in Botswana: A multi-stage approach.

Human immunodeficiency virus (HIV) remains a significant public health issue among young people living in Botswana. There is a need for reliable and valid psychological and behavioural measures of causally important constructs for this population. We developed a new HIV knowledge measure for use with 10-19-year-olds living with HIV and translated and adapted additional tools measuring HIV adjustment, HIV disclosure cognitions and affect, HIV communication beliefs, antiretroviral (ART) adherence, and self-esteem, using a multi-step process. This included (1) item generation for the HIV knowledge questionnaire, (2) translation including back-translation and expert review, (3) cognitive interviewing, (4) reliability testing (5) preliminary validity analysis. The HIV Knowledge Questionnaire for Adolescents living with HIV, the Illness Cognition Questionnaire, the Adolescent HIV Disclosure Cognition and Affect Scale, the HIV Communication Beliefs Scale, and the Rosenberg Self-Esteem Scale showed acceptable or good reliability and some evidence of validity for adolescents living with HIV in Botswana.

Successful use of eculizumab in immediate ANCA vasculitis recurrence in a pediatric kidney transplant.

BACKGROUND: Kidney transplantation is an acceptable therapy end-stage kidney disease secondary to antineutrophil cytoplasmic antibody-associated vasculitis with risk of disease recurrence ranging from 3% to 17%. Standard posttransplant immunosuppression is the mainstay of therapy after recurrence. Recently, new medications focused on complement regulation and avoidance of steroids have been shown to be effective in treating antineutrophil cytoplasmic antibody (ANCA) vasculitis with no studies in the pediatric population. METHODS: We report a 5-year-old patient with immediate recurrence of positive myeloperoxidase (MPO)-ANCA vasculitis after deceased donor kidney transplant and the novel use of eculizumab to salvage the graft. RESULTS: Eculizumab and transition to ravulizumab has been successful in improving graft function and maintenance of disease remission after immediate MPO-ANCA vasculitis recurrence posttransplant. CONCLUSIONS: Complement inhibitors may be used in addition to standard immunosuppression postkidney transplant in a pediatric patient with MPO-ANCA vasculitis recurrence without higher rates of infections.

Protein combined with certain dietary fibers increases butyrate production in gut microbiota fermentation.

The modern diet delivers nearly equal amounts of carbohydrates and protein into the colon representing an important protein increase compared to past higher fiber diets. At the same time, plant-based protein foods have become increasingly popular, and these sources of protein are generally less digestible than animal protein sources. As a result, a significant amount of protein is expected to reach the colon and be available for fermentation by gut microbiota. While studies on diet-microbiota interventions have mainly focused on carbohydrate fermentation, limited attention has been given to the role of protein or protein-fiber mixtures as fermentation substrates for the colonic microbiota. In this study, we aimed to investigate: (1) how changing the ratio of protein to fiber substrates affects the types and quantities of gut microbial metabolites and bacteria; and (2) how the specific fermentation characteristics of different types of fiber might influence the utilization of protein by gut microbes to produce beneficial short chain fatty acids. Our results revealed that protein fermentation in the gut plays a crucial role in shaping the overall composition of microbiota communities and their metabolic outputs. Surprisingly, butyrate production was maintained or increased when fiber and protein were combined, and even when pure protein samples were used as substrates. These findings suggest that indigestible protein in fiber-rich substrates may promote the production of microbial butyrate perhaps including the later stages of fermentation in the large intestine.

Corrigendum: Correlative Live-Cell and Super-Resolution Imaging to Link Presynaptic Molecular Organisation With Function.

[This corrects the article DOI: 10.3389/fnsyn.2022.830583.].

Muscle coordination retraining inspired by musculoskeletal simulations reduces knee contact force.

Humans typically coordinate their muscles to meet movement objectives like minimizing energy expenditure. In the presence of pathology, new objectives gain importance, like reducing loading in an osteoarthritic joint, but people often do not change their muscle coordination patterns to meet these new objectives. Here we use musculoskeletal simulations to identify simple changes in coordination that can be taught using electromyographic biofeedback, achieving the therapeutic goal of reducing joint loading. Our simulations predicted that changing the relative activation of two redundant ankle plantarflexor muscles-the gastrocnemius and soleus-could reduce knee contact force during walking, but it was unclear whether humans could re-coordinate redundant muscles during a complex task like walking. Our experiments showed that after a single session of walking with biofeedback of summary measures of plantarflexor muscle activation, healthy individuals reduced the ratio of gastrocnemius-to-soleus muscle activation by 25 ± 15% (p = 0.004, paired t test, n = 10). Participants who walked with this "gastrocnemius avoidance" gait pattern reduced late-stance knee contact force by 12 ± 12% (p = 0.029, paired t test, n = 8). Simulation-informed coordination retraining could be a promising treatment for knee osteoarthritis and a powerful tool for optimizing coordination for a variety of rehabilitation and performance applications.

Running in the wild: Energetics explain ecological running speeds.

Human runners have long been thought to have the ability to consume a near-constant amount of energy per distance traveled, regardless of speed, allowing speed to be adapted to particular task demands with minimal energetic consequence.1-3 However, recent and more precise laboratory measures indicate that humans may in fact have an energy-optimal running speed.4-6 Here, we characterize runners' speeds in a free-living environment and determine if preferred speed is consistent with task- or energy-dependent objectives. We analyzed a large-scale dataset of free-living runners, which was collected via a commercial fitness tracking device, and found that individual runners preferred a particular speed that did not change across commonly run distances. We compared the data from lab experiments that measured participants' energy-optimal running speeds with the free-living preferred speeds of age- and gender-matched runners in our dataset and found the speeds to be indistinguishable. Human runners prefer a particular running speed that is independent of task distance and is consistent with the objective of minimizing energy expenditure. Our findings offer an insight into the biological objectives that shape human running preferences in the real world-an important consideration when examining human ecology or creating training strategies to improve performance and prevent injury.

Correlative Live-Cell and Super-Resolution Imaging to Link Presynaptic Molecular Organisation With Function.

Information transfer at synapses occurs when vesicles fuse with the plasma membrane to release neurotransmitters, which then bind to receptors at the postsynaptic membrane. The process of neurotransmitter release varies dramatically between different synapses, but little is known about how this heterogeneity emerges. The development of super-resolution microscopy has revealed that synaptic proteins are precisely organised within and between the two parts of the synapse and that this precise spatiotemporal organisation fine-tunes neurotransmission. However, it remains unclear if variability in release probability could be attributed to the nanoscale organisation of one or several proteins of the release machinery. To begin to address this question, we have developed a pipeline for correlative functional and super-resolution microscopy, taking advantage of recent technological advancements enabling multicolour imaging. Here we demonstrate the combination of live imaging of SypHy-RGECO, a unique dual reporter that simultaneously measures presynaptic calcium influx and neurotransmitter release, with post hoc immunolabelling and multicolour single molecule localisation microscopy, to investigate the structure-function relationship at individual presynaptic boutons.

Creating a Cognitive Aid for Use During Intraoperative Power Failures.

An intraoperative power failure (IOPF) is a complete or partial absence of the electrical power supply with or without the availability of a backup generator system during an operative or other invasive procedure. An IOPF can be stressful for the OR team and puts surgical patients at risk for adverse outcomes. To prepare providers for an IOPF, a CRNA piloted a project to create an evidence-based, facility-specific cognitive aid (CA) to guide decision making and enhance patient management and outcomes during an IOPF. The project team tested the battery-power capabilities of essential anesthesia equipment, including anesthesia gas machines, IV pumps, and vital sign monitors, and included the results in the CA. A needs assessment survey was sent to the anesthesia professionals at the facility to promote clinician buy-in and solicit feedback for creating the CA.

Associations of somatic depressive symptoms with food attentional bias and eating behaviors.

Recent evidence suggests that atypical major depressive disorder (MDD) - whose key features include the reversed somatic symptoms of hyperphagia (increased appetite) and hypersomnia (increased sleep) - is a stronger predictor of future obesity than other MDD subtypes. The mechanisms underlying this relationship are unclear. The present study sought to elucidate whether the individual symptoms of hyperphagia, hypersomnia, poor appetite, and disturbed sleep have differential relationships with food attentional bias, emotional eating, external eating, and restrained eating. This cross-sectional laboratory study involved 103 young adults without obesity (mean age = 20 years, 79% female, 26% non-White, mean BMI = 23.4 kg/m2). We measured total depressive symptom severity and individual symptoms of hyperphagia, poor appetite, and disturbed sleep using the Hopkins Symptom Checklist-20 (SCL-20) and added an item to assess hypersomnia; food attentional bias using a Food Stroop task; and self-reported eating behaviors using the Dutch Eating Behavior Questionnaire. Hyperphagia was positively associated with emotional eating but negatively associated with food attentional bias. Hypersomnia was negatively associated with emotional eating. Poor appetite was negatively associated with emotional eating. Disturbed sleep was positively associated with food attentional bias and emotional eating. An aggregate of the remaining 15 depressive symptoms (SCL-15) was positively associated with emotional and restrained eating. Our findings highlight the importance of examining the direction of somatic depressive symptoms, and they set the stage for future research to identify subgroups of people with depression at greatest risk for obesity (e.g., those with hyperphagia and/or disturbed sleep) and the mechanisms responsible for this elevated risk (e.g., emotional eating).

SMOFlipid vs Intralipid 20%: Effect of Mixed-Oil vs Soybean-Oil Emulsion on Parenteral Nutrition-Associated Cholestasis in the Neonatal Population.

BACKGROUND: Parenteral nutrition (PN) is critical for the growth and development of premature neonates who are unable to reach nutrition goals enterally. Using soybean-oil emulsions in PN is a risk factor for cholestasis, leading to alternative dosing strategies including a reduction in total lipid prescribed. Recently, SMOFlipid has been utilized with the goal of avoiding cholestasis while maintaining energy intake. The aim of our study was to compare the incidence of PN-associated cholestasis (PNAC) in patients admitted to the neonatal intensive care unit (NICU) who received either Intralipid 20% or SMOFlipid. METHODS: This single-center, retrospective study evaluated all NICU patients who received PN for ≥14 days. Patients who received SMOFlipid were compared with those who received Intralipid. The primary end point was incidence of PNAC. Secondary end points included (1) prevalence of elevated liver function tests; (2) effect on select laboratory parameters; (3) development of PNAC by age; and (4) incidence of retinopathy of prematurity. RESULTS: A total of 136 neonates were included. Nine of 55 patients (16.4%) in the Intralipid group and 2 of 81 patients (2.5%) in the SMOFlipid group developed cholestasis, defined as direct bilirubin > 2 mg/dL or direct bilirubin > 20% of total bilirubin, when total bilirubin is >5 mg/dL, on or before 30 days post initiation of PN (P = .007). CONCLUSION: Use of SMOFlipid as the lipid emulsion component of PN may be beneficial in prevention of PNAC in NICU patients that are receiving PN for ≥2 weeks.

Self-selected step length asymmetry is not explained by energy cost minimization in individuals with chronic stroke.

BACKGROUND: Asymmetric gait post-stroke is associated with decreased mobility, yet individuals with chronic stroke often self-select an asymmetric gait despite being capable of walking more symmetrically. The purpose of this study was to test whether self-selected asymmetry could be explained by energy cost minimization. We hypothesized that short-term deviations from self-selected asymmetry would result in increased metabolic energy consumption, despite being associated with long-term rehabilitation benefits. Other studies have found no difference in metabolic rate across different levels of enforced asymmetry among individuals with chronic stroke, but used methods that left some uncertainty to be resolved. METHODS: In this study, ten individuals with chronic stroke walked on a treadmill at participant-specific speeds while voluntarily altering step length asymmetry. We included only participants with clinically relevant self-selected asymmetry who were able to significantly alter asymmetry using visual biofeedback. Conditions included targeting zero asymmetry, self-selected asymmetry, and double the self-selected asymmetry. Participants were trained with the biofeedback system in one session, and data were collected in three subsequent sessions with repeated measures. Self-selected asymmetry was consistent across sessions. A similar protocol was conducted among unimpaired participants. RESULTS: Participants with chronic stroke substantially altered step length asymmetry using biofeedback, but this did not affect metabolic rate (ANOVA, p = 0.68). In unimpaired participants, self-selected step length asymmetry was close to zero and corresponded to the lowest metabolic energy cost (ANOVA, p = 6e-4). While the symmetry of unimpaired gait may be the result of energy cost minimization, self-selected step length asymmetry in individuals with chronic stroke cannot be explained by a similar least-effort drive. CONCLUSIONS: Interventions that encourage changes in step length asymmetry by manipulating metabolic energy consumption may be effective because these therapies would not have to overcome a metabolic penalty for altering asymmetry.

Foot strike pattern during running alters muscle-tendon dynamics of the gastrocnemius and the soleus.

Running is thought to be an efficient gait due, in part, to the behavior of the plantar flexor muscles and elastic energy storage in the Achilles tendon. Although plantar flexor muscle mechanics and Achilles tendon energy storage have been explored during rearfoot striking, they have not been fully characterized during forefoot striking. This study examined how plantar flexor muscle-tendon mechanics during running differs between rearfoot and forefoot striking. We used musculoskeletal simulations, driven by joint angles and electromyography recorded from runners using both rearfoot and forefoot striking running patterns, to characterize plantar flexor muscle-tendon mechanics. The simulations revealed that foot strike pattern affected the soleus and gastrocnemius differently. For the soleus, forefoot striking decreased tendon energy storage and fiber work done while the muscle fibers were shortening compared to rearfoot striking. For the gastrocnemius, forefoot striking increased muscle activation and fiber work done while the muscle fibers were lengthening compared to rearfoot striking. These changes in gastrocnemius mechanics suggest that runners planning to convert to forefoot striking might benefit from a progressive eccentric gastrocnemius strengthening program to avoid injury.

Faecal volatile organic compounds in preterm babies at risk of necrotising enterocolitis: the DOVE study.

BACKGROUND: Early diagnosis of necrotising enterocolitis (NEC) may improve prognosis but there are no proven biomarkers. OBJECTIVE: To investigate changes in faecal volatile organic compounds (VOCs) as potential biomarkers for NEC. DESIGN: Multicentre prospective study. SETTINGS: 8 UK neonatal units. PATIENTS: Preterm infants <34 weeks gestation. METHODS: Daily faecal samples were collected prospectively from 1326 babies of whom 49 subsequently developed definite NEC. Faecal samples from 32 NEC cases were compared with samples from frequency-matched controls without NEC. Headspace, solid phase microextraction gas chromatography/mass spectrometry was performed and VOCs identified from reference libraries. VOC samples from cases and controls were compared using both discriminant and factor analysis methods. RESULTS: VOCs were found to cluster into nine groups (factors), three were associated with NEC and indicated the possibility of disease up to 3-4 days before the clinical diagnosis was established. For one factor, a 1 SD increase increased the odds of developing NEC by 1.6 times; a similar decrease of the two other factors was associated with a reduced risk (OR 0.5 or 0.7, respectively). Discriminant analyses identified five individual VOCs, which are associated with NEC in babies at risk, each with an area under the receiver operating characteristics curve of 0.75-0.76, up to 4 days before the clinical diagnosis was made. CONCLUSIONS: Faecal VOCs are altered in preterm infants with NEC. These data are currently insufficient to enable reliable cotside detection of babies at risk of developing NEC and further work is needed investigate the role of VOCs in clarifying the aetiology of NEC.

HIV-1 Rev interacts with HERV-K RcREs present in the human genome and promotes export of unspliced HERV-K proviral RNA.

BACKGROUND: The HERV-K (HML-2) viruses are the youngest of the human endogenous retroviruses. They are present as several almost complete proviral copies and numerous fragments in the human genome. Many HERV-K proviruses express a regulatory protein Rec, which binds to an element present in HERV-K mRNAs called the RcRE. This interaction is necessary for the nucleo-cytoplasmic export and expression of HERV-K mRNAs that retain introns and plays a role analogous to that of Rev and the RRE in HIV replication. There are over 900 HERV-K RcREs distributed throughout the human genome. Thus, it was of interest to determine if Rev could functionally interact with selected RcRE elements that map either to HERV-K proviruses or human gene regions. This interaction would have the potential to alter the expression of both HERV-K mRNAs and cellular mRNAs during HIV-1 infection. RESULTS: In this study we employed a combination of RNAseq, bioinformatics and cell-based functional assays. Potential RcREs were identified through a number of bioinformatic approaches. They were then tested for their ability to promote export and translation of a reporter mRNA with a retained intron in conjunction with Rev or Rec. Some of the selected elements functioned well with either Rev, Rec or both, whereas some showed little or no function. Rev function on individual RcREs varied and was also dependent on the Rev sequence. We also performed RNAseq on total and cytoplasmic RNA isolated from SupT1 cells expressing HIV Rev, with or without Tat, or HERV-K Rec. Proviral mRNA from three HERV-K loci (4p16.1b, 22q11.23 and most significantly 3q12.3) accumulated in the cytoplasm in the presence of Rev or Tat and Rev, but not Rec. Consistent with this, the 3' RcRE from 3q12.3 functioned well with HIV-Rev in our reporter assay. In contrast, this RcRE showed little or no function with Rec. CONCLUSIONS: The HIV Rev protein can functionally interact with many RcREs present in the human genome, depending on the RcRE sequence, as well as the Rev sequence. This leads to export of some of the HERV-K proviral mRNAs and also has the potential to change the expression of non-viral genes.

Heuristic-Based Ankle Exoskeleton Control for Co-Adaptive Assistance of Human Locomotion.

Assisting human locomotion with exoskeletons is challenging, largely due to the complexity of the neuromusculoskeletal system, the time-varying dynamics that accompany motor learning, and the uniqueness of every individual's response to device assistance. Assistance strategies designed to keep the human "in-the-loop" can help overcome many of these challenges. The purpose of this study was to develop a human-in-the-loop assistance strategy that uses co-adaptive control to slowly and continuously respond to biomechanical changes thought to encode the user's needs. Online measurements of muscle activity and joint kinematics were used to guide the evolution of an exoskeleton torque pattern based on the following heuristics: 1) muscle activity that acts cooperatively with the exoskeleton indicates the user wants more torque; 2) muscle activity that acts antagonistically to the exoskeleton indicates the user wants less torque; and 3) torque should stop increasing if the user is not adapting. We applied our controller to tethered, bilateral ankle exoskeletons worn by naïve participants as they walked on a treadmill at 1.25 m · s-1 for 30 minutes. The evolved torque profiles reduced the root-mean-square of soleus muscle activity by 35±12% and metabolic rate by 22±8% compared to walking with the exoskeletons while they provided no torque. This was equivalent to a 9±12% reduction in metabolic rate when compared to normal walking. Furthermore, the algorithm was responsive to changes in each user's coordination patterns. These results confirm the effectiveness of the controller and suggest a new approach to exoskeleton assistance aimed at fostering co-adaptation with the user. This technique might particularly benefit individuals with age-related muscle weakness.

Connecting the legs with a spring improves human running economy.

Human running is inefficient. For every 10 calories burned, less than 1 is needed to maintain a constant forward velocity - the remaining energy is, in a sense, wasted. The majority of this wasted energy is expended to support the bodyweight and redirect the center of mass during the stance phase of gait. An order of magnitude less energy is expended to brake and accelerate the swinging leg. Accordingly, most devices designed to increase running efficiency have targeted the costlier stance phase of gait. An alternative approach is seen in nature: spring-like tissues in some animals and humans are believed to assist leg swing. While it has been assumed that such a spring simply offloads the muscles that swing the legs, thus saving energy, this mechanism has not been experimentally investigated. Here, we show that a spring, or 'exotendon', connecting the legs of a human reduces the energy required for running by 6.4±2.8%, and does so through a complex mechanism that produces savings beyond those associated with leg swing. The exotendon applies assistive forces to the swinging legs, increasing the energy optimal stride frequency. Runners then adopt this frequency, taking faster and shorter strides, and reduce the joint mechanical work to redirect their center of mass. Our study shows how a simple spring improves running economy through a complex interaction between the changing dynamics of the body and the adaptive strategies of the runner, highlighting the importance of considering each when designing systems that couple human and machine.

Lipolysis in Brown Adipocytes Is Not Essential for Cold-Induced Thermogenesis in Mice.

Lipid droplet (LD) lipolysis in brown adipose tissue (BAT) is generally considered to be required for cold-induced nonshivering thermogenesis. Here, we show that mice lacking BAT Comparative Gene Identification-58 (CGI-58), a lipolytic activator essential for the stimulated LD lipolysis, have normal thermogenic capacity and are not cold sensitive. Relative to littermate controls, these animals had higher body temperatures when they were provided food during cold exposure. The increase in body temperature in the fed, cold-exposed knockout mice was associated with increased energy expenditure and with increased sympathetic innervation and browning of white adipose tissue (WAT). Mice lacking CGI-58 in both BAT and WAT were cold sensitive, but only in the fasted state. Thus, LD lipolysis in BAT is not essential for cold-induced nonshivering thermogenesis in vivo. Rather, CGI-58-dependent LD lipolysis in BAT regulates WAT thermogenesis, and our data uncover an essential role of WAT lipolysis in fueling thermogenesis during fasting.

Muscle recruitment and coordination with an ankle exoskeleton.

Exoskeletons have the potential to assist and augment human performance. Understanding how users adapt their movement and neuromuscular control in response to external assistance is important to inform the design of these devices. The aim of this research was to evaluate changes in muscle recruitment and coordination for ten unimpaired individuals walking with an ankle exoskeleton. We evaluated changes in the activity of individual muscles, cocontraction levels, and synergistic patterns of muscle coordination with increasing exoskeleton work and torque. Participants were able to selectively reduce activity of the ankle plantarflexors with increasing exoskeleton assistance. Increasing exoskeleton net work resulted in greater reductions in muscle activity than increasing exoskeleton torque. Patterns of muscle coordination were not restricted or constrained to synergistic patterns observed during unassisted walking. While three synergies could describe nearly 95% of the variance in electromyography data during unassisted walking, these same synergies could describe only 85-90% of the variance in muscle activity while walking with the exoskeleton. Synergies calculated with the exoskeleton demonstrated greater changes in synergy weights with increasing exoskeleton work versus greater changes in synergy activations with increasing exoskeleton torque. These results support the theory that unimpaired individuals do not exclusively use central pattern generators or other low-level building blocks to coordinate muscle activity, especially when learning a new task or adapting to external assistance, and demonstrate the potential for using exoskeletons to modulate muscle recruitment and coordination patterns for rehabilitation or performance.