Initial Stimulus Research Articles

Focal changes in alpha oscillations during short-term memorization of pain: a high-density electroencephalogram study with source localization.

Memories of painful events constitute the basis for assessing patients' pain. This study explores the brain oscillatory activity during short-term memorization of a nociceptive stimulus. High-density EEG activity (128 electrodes) was recorded in 13 healthy subjects during a match-to-sample sensory discrimination task, whereby participants compared the intensity of a thumb-located electric shock (S2) with a prior stimulus to the same location (S1) delivered 8-10s earlier. Stimuli were above or below the individual nociceptive threshold. EEG activity with intracortical source localization via LORETA source reconstruction was analysed during the inter-stimuli period and contrasted with a non-memory-related control task. The inter-stimulus memorization phase was characterized by a focal alpha-activity enhancement, significant during the nociceptive condition only, which progressed from bilateral occipital regions (cuneus and mid-occipital gyri) during the first encoding-memorization phase towards the right-superior and right mid-temporal gyri during the 2-4s immediately preceding S2. Initial alpha enhancement in occipital areas/cuneus is consistent with rapid non-specific inhibition of task-irrelevant visual processing during initial stimulus encoding. Its transfer to the right-temporal regions was concomitant to the temporary upholding of the stimulus perceptual representation, previous to receiving S2, and suggests an active and local blockade of external interferences while these regions actively maintain internal information. These results add to a growing field indicating that alpha oscillations, while indicating local inhibitory processes, can also indirectly reveal active stimulus handling, including maintenance in short-term memory buffers, by objectivizing the filtering out of irrelevant and potentially disrupting inputs in brain regions engaged in internally driven operations.

Global Proteomics Analysis of Lysophosphatidic Acid Signaling in PC-3 Human Prostate Cancer Cells: Role of CCN1.

Cysteine-rich angiogenic factor 61 (CCN1/Cyr61) is a matricellular protein that is induced and secreted in response to growth factors. Our previous work showed that 18:1-lysophosphatidic acid (LPA), which activates the G protein-coupled receptor LPAR1, induces CCN1 between 2-4 h in PC-3 human prostate cancer cells in a manner than enhances cell-substrate adhesion. While the time course of induction suggests that CCN1 contributes to intermediate events in LPA action, the roles of CCN1 in LPA-mediated signal transduction have not been fully elucidated. This study utilized a comprehensive global proteomics approach to identify proteins up- or down-regulated in response to treatment of PC-3 cells with LPA for three hours, during the time of peak CCN1 levels. In addition, the effects of siRNA-mediated CCN1 knockdown on LPA responses were analyzed. The results show that, in addition to CCN1, LPA increased the levels of multiple proteins. Proteins up-regulated by LPA included metastasis-associated in colon cancer protein 1 (MACC1) and thrombospondin-1 (TSP1/THBS1); both MACC1 and TSP1 regulated cancer cell adhesion and motility. LPA down-regulated thioredoxin interacting protein (TXNIP). CCN1 knockdown suppressed the LPA-induced up-regulation of 30 proteins; these included MACC1 and TSP1, as confirmed by immunoblotting. Gene ontology and STRING analyses revealed multiple pathways impacted by LPA and CCN1. These results indicate that CCN1 contributes to LPA signaling cascades that occur during the intermediate phase after the initial stimulus. The study provides a rationale for the development of interventions to disrupt the LPA-CCN1 axis.

Effects of ondansetron exposure during ICU stay on outcomes of critically ill patients with sepsis: a cohort study.

Sepsis is a life-threatening disease with high morbidity and mortality, characterized by an inadequate systemic immune response to an initial stimulus. Whether the use of ondansetron (OND) during intensive care unit (ICU) stay is associated with the prognosis of sepsis patients remains unclear. Critically ill patients with sepsis were extracted from the Medical Information Mart for Intensive Care IV (MIMIC-IV) database. Multivariate logistic regression and Cox regression analyses were used to explore the association between OND use and clinical outcomes after adjusting for confounders. Kaplan-Meier survival curve was used for survival analysis. Propensity score matching (PSM) and subgroup analysis were performed to further confirm the results. The OND-medication group showed reduced in-hospital mortality, 28-day and 90-day mortalities. The OR for in-hospital mortality was 0.80 (0.64-0.99) and HRs for 28-day mortality and 90-day mortality were 0.77 (0.64-0.92) and 0.83 (0.70-0.98), respectively. After PSM, the clinical outcomes remained consistent. In-hospital mortality was lower in the OND-medication group (28.1% vs. 35.8%, P= 0.044), as well as 28-day mortality (23.4% vs. 32.1%, P=0.022) and 90-day mortality (27.4% vs. 35.8%, P=0.035). The protective effect of OND in sepsis patients was relatively robust, independent of age, septic shock, vasopressin and mechanical ventilation. Additionally, the OND users had longer lengths of stay in ICU (6.9(3.1-13.2) vs. 5.1(2.5-11.0), P = 0.026) while no statistical differences were found in lengths of stay in hospital (P = 0.333). OND exposure might be associated with lower in-hospital, 28-day, and 90-day mortality rates in critically ill patients with sepsis. This study indicated that OND might help improve the prognosis of patients with sepsis.

A novel clinical protocol for dentin hypersensitivity management based on regenerative dental gel associated with calcium: A case study in a patient with periodontal disease

Introduction: Dentin hypersensitivity (DH) is defined as pain caused by dentin exposure in response to various stimuli. Patients with periodontal disease (PD) frequently report DH due to root surface exposure or after periodontal treatment. Bioactive agents derived from calcium and/or silicon-based systems, such as REFIX technology, have been used to promote tooth regeneration, with focus on tooth sensitivity treatment. Case Report: Based on this, the efficacy of REFIX gel combined with calcium on the treatment of a DH was evaluated in a PD 45-year-old male patient. The patient’s right and left sides were randomly selected to use one of the prophylaxis dental protocols: REFIX dental gel/calcium (RDGCa) (experimental: 13, 14, 15 teeth) or Pumice Stone (PS) (control: 23, 24, 25 teeth). The products were applied using dental polishing brush during 10 seconds in each tooth surface. Schiff Air Index (SAI) for sensitive teeth (0–3) were performed by applying air jet to each tooth’s vestibular surface for 5 seconds after and before the prophylaxis. The patient reported pain and interruption of the stimulus before and after PS prophylaxis (SAI 3 and 3 respectively). There was a reduction in pain when RDGCa protocol was used (SAI 3—before/SAI 1—after). In this instance, the patient felt the stimulus but did not request to be interrupted. This contrasted with the outcomes of the initial stimulus as well as PS. Conclusion: The results showed that the RDGCa strategy was successful in lowering DH in PD patients.

Dynamic Analysis of Neuron Models

Based on the Hodgkin–Huxley theory, this paper establishes several nonlinear system models, analyzes the models’ stability, and studies the conditions for repetitive discharge of neuronal membrane potential. Our dynamic analysis showed that the main channel currents (the fast transient sodium current, the potassium delayed rectifier current, and the fixed leak current) of a neuron determine its dynamic properties and that the GHK formula will greatly widen the stimulation current range of the repetitive discharge condition compared with the Nernst equation. The model including the change in ion concentration will lead to spreading depression (SD)-like depolarization, and the inclusion of a Na-K pump will weaken the current stimulation effect by decreasing the extracellular K accumulation. The results indicate that the Hodgkin–Huxley model is suitable for describing the response to initial stimuli, but due to changes in ion concentration, it is not suitable for describing the response to long-term stimuli.

Expression of TNFR1, VEGFA, CD147 and MCT1 as early biomarkers of diabetes complications and the impact of aging on this profile

Hyperglycemia leads to microvascular lesions in various tissues. In diabetic nephropathy—DN, alterations in usual markers reflect an already installed disease. The study of new biomarkers for the early detection of diabetic complications can bring new prevention perspectives. Rats were divided into diabetic adult—DMA—or elderly—DME and control sham adult—CSA—or control sham elderly—CSE. Blood and urine samples were collected for biochemical analysis. Bulbar region, cardiac, hepatic and renal tissues were collected for target gene expression studies. As result, DMA showed decreased TNFR1, MCT1 and CD147 expression in the bulbar region, TNFR1 in the heart, VEGFA and CD147 in the kidney and TNFR1 in blood. Positive correlations were found between TNFR1 and MCT1 in the bulbar region and HbA1c and plasma creatinine, respectively. DME showed positive correlation in the bulbar region between TNFR1 and glycemia, in addition to negative correlations between CD147 in the heart versus glycemia and urea. We concluded that the initial hyperglycemic stimulus already promotes changes in the expression of genes involved in the inflammatory and metabolic pathways, and aging alters this profile. These changes prior to the onset of diseases such as DN, show that they have potential for early biomarkers studies.

Potential of rosmarinic acid from Orthosiphon aristatus extract for inflammatory induced diseases and its mechanisms of action

Orthosiphon aristatus has been traditionally used as a medicinal herb for various illnesses in Southeast Asia and Europe. The most dominant bioactive compound of the herb is rosmarinic acid (RosA) which has been demonstrated for its remarkable anti-inflammatory properties. This review describes the recent progress of studies on multi-target molecular pathways of RosA in relation to targeted inflammatory-associated diseases. An inclusive literature search was conducted using electronic databases such as Google Scholar, Scopus, Springer Link, PubMed, Medline, Wiley and Science Direct for studies reporting on the anti-inflammatory actions of RosA from 2008 until 2023. The keywords of the search were RosA and anti-inflammatory in relation to hepatoprotective, chondroprotective, cardioprotective, neuroprotective and toxicity. Only publications that are written in English are included in this review. The inhibition and deactivation of pro-inflammatory biomolecules by RosA were explained based on the initial inflammation stimuli and their location in the body. The activation of Nrf2/HO-1 expression to inhibit NF-κB pathway is the key mechanism for hepatoprotection. Besides NF-κB inhibition, RosA activates PPARγ to alleviate ischemia/reperfusion (I/R)-induced myocardial injury for cardioprotection. The regulation of MAPK and T-cell activation is important for chondroprotection, whereas the anti-oxidant property of RosA is the main contributor of neuroprotection. Even though less studies on the anti-inflammation of RosA extracts from O. aristatus, but the effective pharmacological properties of RosA has promoted it as a natural potent lead for further investigation.

Experienced Meditators Show Multifaceted Attention-Related Differences in Neural Activity

ObjectivesMindfulness meditation (MM) is suggested to improve attention. Research has explored this using the “attentional-blink” (AB) task, where stimuli are rapidly presented, and a second target stimulus (T2) is often missed if presented ~300 ms after an initial target stimulus (T1). Previous research has shown improved task accuracy during the AB task and altered neural activity following an intensive 3-month MM retreat. We tested whether these results replicated in a community sample of typical meditators.MethodThirty-one mindfulness meditators and 30 non-meditators completed an AB task while electroencephalography (EEG) was recorded. Between-group comparisons were made for task accuracy, event-related potential activity (posterior-N2 and P3b), theta and alpha oscillatory phase synchronisation to stimuli presentation, and alpha-power. The primary aim was to examine effects within the time windows reported in previous research. Additional exploratory aims assessed effects across broader time windows.ResultsNo differences were detected in task accuracy or neural activity within our primary hypotheses. However, exploratory analyses showed posterior-N2 and theta phase synchronisation (where the phase of theta oscillations were synchronised to stimuli onset) effects indicating meditators showed a priority towards attending to T2 stimuli (p < 0.01). Meditators also showed more alpha-phase synchronisation, and lower alpha-power (with smaller amplitudes of activity in the alpha frequency) when processing T2 stimuli (p < 0.025).ConclusionsOur results showed multiple differences in neural activity that suggested enhanced attention in meditators. The neural activity patterns in meditators aligned with theoretical perspectives on activity associated with enhanced cognitive performance. These include enhanced alpha “gating” mechanisms (where alpha activity acts as a filter between sensory and higher order neural processes), increased oscillatory synchronisation to stimuli, and more equal allocation of neural activity across stimuli. However, meditators did not show higher task accuracy, nor were the effects consistent with our primary hypotheses or previous research.PreregistrationThis study was not preregistered.

Интерпретационный потенциал игрового слова С.Д. Крижановского в свете читательской рецепции

This paper is devoted to the aspects of readers’ perception and associative fullness of S.D. Krzhizhanovsky’s game (“bizarre”) word. The data were collected through a chain-like association experiment. The tasks for the experiment were based on the titles of S.D. Krzhizhanovsky’s novels, which represent the author’s idiostyle and are aimed to enhance the variety of the readers’ feedback in the process of exposure to the stimuli. The test subjects were asked to write association chains for the title and compose a small text using the words from one of these chains. For this article, the scope of the study was limited to the results of the interpretation of the stimulus “Stravaging ‘Strange’”. The main strategies for building the association chains could be narrowed down to three types: reaction only to a part of the title, without recognition of the full game potential; reaction to the stimulus’ game potential; reaction actualizing individual ideas of the recipient that cannot be traced back to the initial stimulus. The obtained results require further examination in order to study the full range of the reactions acquired in the experiment, for example, the analysis of the structure of association chains and characteristics of the semantic groups that were used. Those findings could become the foundation for the methodology of studying literary text with acknowledgement of psychological reality perception.

Tobacco withdrawal-induced changes in sensorimotor filtering as a predictor of smoking lapse in trauma-exposed individuals

Prepulse inhibition (PPI) is a measure of sensorimotor filtering thought to shield the processing of initial weaker auditory stimuli from interruption by a later startle response. Previous studies have shown smoking withdrawal to have a negative impact on sensorimotor filtering, particularly in individuals with psychopathology. Because tobacco use may alleviate sensory and sensorimotor filtering deficits, we examined whether smoking withdrawal-induced changes in PPI were associated with maintenance of smoking abstinence in trauma-exposed individuals with and without PTSD who were attempting to quit smoking. Thirty-eight individuals (n = 24 with current or past PTSD; 14 trauma-exposed healthy controls) made an acute biochemically-verified smoking cessation attempt supported by 8 days of contingency management (CM) and cognitive behavioral therapy (CBT) for smoking. Participants completed a PPI task at the pre-quit baseline, 2 days post-quit, and 5 days post-quit. Post-quit changes in PPI were compared between those who remained abstinent for the first 8-days of the quit attempt and those who lapsed back to smoking. PPI changes induced by biochemically-verified smoking abstinence were associated with maintenance of abstinence across the 8-day CM/CBT-supported quit attempt. As compared to those who maintained tobacco abstinence, participants who lapsed to smoking had significantly lower PPI at 2 and 5 days post-quit relative to baseline. Thus, among trauma-exposed individuals, decreases in PPI during acute smoking cessation supported by CM/CBT are associated with lapse back to smoking. Interventions that improve PPI during early smoking abstinence may facilitate smoking cessation among such individuals who are at high risk for chronic, refractory tobacco use.

Remembering foods and foes: emerging principles of transcriptional memory.

Transcriptional memory is characterized by a primed cellular state, induced by an external stimulus that results in an altered expression of primed genes upon re-exposure to the inducing signal. Intriguingly, the primed state is heritably maintained across somatic cell divisions even after the initial stimulus and target gene transcription cease. This phenomenon is widely observed across various organisms and appears to enable cells to retain a memory of external signals, thereby adapting to environmental changes. Signals range from nutrient supplies (food) to a variety of stress signals, including exposure to pathogens (foes), leading to long-term memory such as in the case of trained immunity in plants and mammals. Here, we review these priming phenomena and our current understanding of transcriptional memory. We consider different mechanistic models for how memory can work and discuss existing evidence for potential carriers of memory. Key molecular signatures include: the poising of RNA polymerase II machinery, maintenance of histone marks, as well as alterations in nuclear positioning and long-range chromatin interactions. Finally, we discuss the potential adaptive roles of transcriptional memory in the organismal response to its environment from nutrient sensing to trained immunity.

Prolonged and specific spatial training during adolescence reverses adult hippocampal network impairments in a mouse model of fragile X syndrome

The fragile X syndrome (FXS) is the leading monogenetic cause of cognitive impairment and autism. A hallmark of FXS in patients and the FXS mouse model (Fmr1 KO) is an overabundance of immature appearing dendritic spines in the cortex and hippocampus which is associated with behavioral deficits. Spine analysis in the different hippocampal subregions and at different developmental stages revealed that in adult mice, hippocampal spine pathology occurs specifically in the CA3 subregion, which plays a pivotal role in pattern completion processes important for efficient memory recall from parts of the initial memory stimulus. In line with this synaptic defect we document an impairment in memory recall during partially cued reference memory test in the Morris water maze task. This is accompanied by impaired recruitment of engram cells as well as impaired spine structural plasticity in the CA3 region. In order to promote hippocampal network development adolescent mice were either raised in an enriched environment or subjected to specific hippocampus-dependent spatial training. Intriguingly, only specific spatial training alleviated the cognitive symptoms and the spine phenotype shown in adult Fmr1 KO mice suggesting that specific stimulation of hippocampal networks during development might be used in the future as a therapeutic strategy.

Development of Image Series Media in Text Descriptive to Improve English Speaking Skills

Speaking skills are seen as a very important skill to be understood by learners of a language. This is related to the function of language as a means of communication which requires its users to be able to use the language in real communication. The implication of this is that teachers should be able to create a learning environment that is able to facilitate learners to practice functional expressions actively and communicatively. Meanwhile, speaking skill is considered as one of the language skills that is used as a benchmark in determining the quality of ability. This research uses the method of methods (SLR). regarding research methods: "Literature" which means it is a critical analysis of the research that is being done on a special topic or in the form of a question to a part of science. helps us in compiling a framework that is in accordance with the theory, findings, and results of previous research in solving the problem formulation in the research that we make. The SLR method is used to identify, review, evaluate and interpret all available research with the topic area of the phenomenon of interest, with specific relevant research questions. With the use of the SLR Method, a systematic review and identification of journals can be carried out. The results of the study are described basically the ability to speak can be influenced by the methods and media provided, the initial stimulus carried out by the teacher will be able to stimulate the child's ability, especially at the psychomotor level, interesting learning media will certainly have an influence on students during the teaching and learning process in the classroom. For this reason, the role of the teacher as a facilitator is expected in providing stimulus to students.

#3830 TRAINED INNATE IMMUNITY IN RESPONSE TO NUCLEAR ANTIGENS IN SYSTEMIC LUPUS ERYTHEMATOSUS

Abstract Background and Aims Systemic lupus erythematosus (SLE) is an autoimmune disease directed against nuclear antigens, including those derived from apoptotic microparticles (MPs) and neutrophil extracellular traps (NETs). Innate immune cells display an hyperreactive phenotype in patients with SLE, with increased expression of immunostimulatory surface markers and increased production of proinflammatory cytokines. We hypothesize that the hyperreactive phenotype of innate immune cells in SLE is caused by the induction of trained immunity. Trained immunity is a de facto innate immune memory elicited by an initial stimulus that induces metabolic and epigenetic changes and results in a more vigorous inflammatory response to subsequent stimuli. Here we aim to investigate whether nuclear autoantigens derived from MPs and NETs can induce trained immunity in SLE patients. Method To investigate the capability of MPs and NETs to induce trained immunity we stimulated healthy PBMCs with isolated NETs and MPs or with plasma from SLE patients for 24 hours, washed and rested the cells for five days. Cells were restimulated with lipopolysaccharide (LPS) and Pam3CSK4. To test the activation status of innate immune cells, PBMCs were isolated from patients with SLE and healthy controls and stimulated the cells with different TLR agonists. Cytokine production was measured using ELISA. Immune cell subsets in SLE patients were analyzed by flow cytometry. We performed RNA sequencing and Chromatin immunoprecipitation (ChIP) sequencing for histone 3 lysine 4 trimethylation (H3K4me3) on monocytes from SLE patients and healthy controls. Results We found that in vitro both MPs and NETs, as well as plasma from SLE patients, can induce trained immunity. Initial stimulation with MPs, NETs or SLE plasma resulted in increased production of Tumor necrosis factor (TNF) and Interleukin (IL) 6 upon restimulation with different TLR agonists. Assessment of circulating immune cells showed higher percentages of monocytes in SLE patients compared to healthy controls, and we found that circulating monocytes from SLE patients produce increased levels of pro-inflammatory cytokines (IL-6, IL-1ß, TNF) after stimulation with Toll-like receptor agonists, indicating trained immunity. This is accompanied by increased expression of metabolism and inflammation-related genes, underscoring the hyperreactive phenotype typical in trained innate immune cells. Epigenetic analysis of monocytes revealed major changes in H3K4me3, an epigenetic mark associated with trained immunity. Conclusion Our findings provide new insight into the pathogenesis of SLE by showing that trained immunity can be elicited by SLE-related antigens present in MPs and NETs, and demonstrating that that circulating monocytes from SLE patients have a trained immunity phenotype. Trained immunity yields a possible biomarker for the risk of SLE flares and offers a new potential target for developing therapeutic strategies.

#4443 INNATE IMMUNE MEMORY DETERMINES LONG-TERM KIDNEY ALLOGRAFT SURVIVAL

Abstract Background and Aims Historically, transplant medicine has focused primarily on the adaptive immune system, while the role of innate immune cells in the complex graft-reactive immune response has been understudied. The recently emerging concept of “trained immunity” is of particular interest in this regard. Trained immunity is a phenomenon in which innate immune cells develop a long-lasting memory in response to an initial stimulus, thereby reprogramming cells for a stronger inflammatory response to future stimuli. We hypothesized that damage-associated molecular patterns (DAMPs), released during ischemia-reperfusion injury, and immunosuppressive medication can affect trained immunity, and investigated in a cohort of kidney transplant patients if trained immunity is associated with long-term allograft survival. Method An established in vitro trained immunity assay was used in which human peripheral blood mononuclear cells (PBMCs) were stimulated. After five days of rest, cells were restimulated with lipopolysaccharide (LPS), and IL-6 and TNF were measured in the supernatant as a readout of the trained immunity response (Fig. 1A). We tested a library of DAMPs, and immunosuppressive drugs commonly used in kidney transplantation, to determine their effect on trained immunity. Of 96 kidney transplant recipients, with a follow-up for graft survival &amp;gt;8 years, serum was obtained before- and one week after transplantation. Patient sera were used to stimulate healthy PBMCs in the trained immunity assay. The relationship between serum induced trained immunity and long-term allograft survival was analyzed by Kaplan-Meier and Cox regression analysis. Results We found that DAMPs can affect trained immunity, causing either an enhanced (HMGB1, histones, IL-1β) or suppressed (vimentin, ATP, and C1q) cytokine response after LPS restimulation (Fig. 1B). Prednisone and tacrolimus potently suppressed trained immunity (Fig. 1C). In the kidney transplant patient cohort, cells stimulated with patients’ serum showed considerable heterogeneity in the IL-6 and TNF production after LPS restimulation. The IL-6 and TNF response of cells stimulated with serum obtained one week post-transplantation was lower compared to cells stimulated with serum obtained before transplantation (Difference of 463 ± 428 pg/mL, p&amp;lt;0.001 for IL-6; 1215 ± 1078 pg/mL, p&amp;lt;0.001 for TNF). The trained immunity response to post-transplant obtained serum was strongly associated with long-term death-censored graft survival (p = 0.005 for IL-6 tertials, and p = 0.037 for TNF tertials in a Kaplan-Meier analysis), and remained significant after adjusting for potential confounders. Conclusion Trained immunity can be affected by stimulation with DAMPs, which are released during ischemia-reperfusion injury during transplantation, and by immunosuppressive drugs used in kidney transplantation. The net effect of patients' serum taken one week after transplantation, containing a mixture of DAMPs and immunosuppressive drugs, has a suppressive effect on trained immunity compared with patients' pre-transplant serum. Interestingly, the trained immunity response to post-transplant serum is strongly associated with long-term allograft survival. Thereby we have identified trained immunity as a novel and relevant immunological mechanism in organ transplantation.

Sex differences in isolated skeletal muscle force production: a spectrum of responses

Whether sex differences in skeletal muscle microvascular responses differ in response to muscle contraction is currently unknown. To determine vascular responses to muscle contraction in vivo we use intravital microscopy using thin skeletal muscle models of mixed fibre types (i.e. hamster retractor muscle). However, to effectively quantify this relationship in vivo, the initial muscle contraction stimulus must be constant across the sexes and thus, we must first determine whether there are sex differences in skeletal muscle force generation. We hypothesized that sexual dimorphisms in force production would not be apparent in muscles of any fibre type composition. To test this hypothesis, we used skeletal muscles with unique fibre type characteristics and oxidative capacities. Mouse soleus (SOL: primarily type 1 &gt;75%), extensor digitorum longus (EDL: primarily type IIB ~60%), and costal diaphragm (DIA: primarily type IIA ~55%) muscles were isolated from adult male and female CD-1 mice. The retractor muscle (RET: primarily type IIX ~58%) was also isolated from adult male and female Syrian hamsters. Muscles were electrically stimulated in vitro and force production was quantified at optimal length during a force-frequency test (1-120Hz) and twitch (1Hz) contractions. In mice, females generated greater force during the force-frequency test in SOL (10-120Hz) and EDL (30-120Hz) and generated greater twitch forces compared to males (SOL: female 34.7 ± 2.4 mN/mm 2 , n=21 vs male 27.8 ± 2.0 mN/mm 2 , n=17; EDL: female 41.2 ± 2.2 mN/mm 2 , n=35 vs male 32.5 ± 2.1 mN/mm 2 , n=29). Females generated greater force during the force frequency test in DIA at 30Hz only and no significant sex differences were observed in DIA twitch force (female 0.24 ± 0.02 g/mg, n=19 vs male 0.20 ± 0.02 g/mg, n=21). In hamster RET no significant sex differences in force were observed during the force frequency test or during the twitch contraction (female 0.13 ± 0.01 g/mg, n=19 vs male 0.14 ± 0.02 g/mg, n=20). Collectively, these findings demonstrate that sex differences in force production were observed in muscles primarily comprised of slow oxidative (type 1) and fast glycolytic (type IIB) fibres but not in muscles primarily comprised of intermediate fibres (type IIA and type IIX). These data show that on a spectrum of muscle fibres from slow oxidative to fast glycolytic, sex differences are most apparent on the extremes of the spectrum, whereas sexual dimorphisms in the middle of the spectrum are not apparent. This work is supported by NSERC. NSERC This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Reinforcer value moderates the effects of prenatal alcohol exposure on learning and reversal.

Fetal Alcohol Spectrum Disorders (FASD) are the leading cause of preventable developmental disability and are commonly characterized by alterations in executive function. Reversal learning tasks are reliable, cross-species methods for testing a frequently impaired aspect of executive control, behavioral flexibility. Pre-clinical studies commonly require the use of reinforcers to motivate animals to learn and perform the task. While there are several reinforcers available, the most commonly employed are solid (food pellets) and liquid (sweetened milk) rewards. Previous studies have examined the effects of different solid rewards or liquid dietary content on learning in instrumental responding and found that rodents on liquid reward with higher caloric content performed better with increased response and task acquisition rate. The influence of reinforcer type on reversal learning and how this interacts with developmental insults such as prenatal alcohol exposure (PAE) has not been explored. We tested whether reinforcer type during learning or reversal would impact an established deficit in PAE mice. We found that all male and female mice on liquid reward, regardless of prenatal exposure were better motivated to learn task behaviors during pre-training. Consistent with previous findings, both male and female PAE mice and Saccharine control mice were able to learn the initial stimulus reward associations irrespective of the reinforcer type. During the initial reversal phase, male PAE mice that received pellet rewards exhibited maladaptive perseverative responding whereas male mice that received liquid rewards performed comparable to their control counterparts. Female PAE mice that received either reinforcer types did not exhibit any deficits on behavioral flexibility. Female saccharine control mice that received liquid, but not pellet, rewards showed increased perseverative responding during the early reversal phase. These data suggest that reinforcer type can have a major impact on motivation, and therefore performance, during reversal learning. Highly motivating rewards may mask behavioral deficits seen with more moderately sought rewards and gestational exposure to the non-caloric sweetener, saccharine, can impact behavior motivated by those reinforcers in a sex-dependent manner.

Endophilin-A/SH3GL2 calcium switch for synaptic autophagy induction is impaired by a Parkinson’s risk variant

ABSTRACT At the synapse, proteins are reused several times during neuronal activity, causing a decline in protein function over time. Although emerging evidence supports a role of autophagy in synaptic function, the precise molecular mechanisms linking neuronal activity, autophagy and synaptic dysfunction are vastly unknown. We show how extracellular calcium influx in the pre-synaptic terminal constitutes the initial stimulus for autophagosome formation in response to neuronal activity. This mechanism likely acts to rapidly support synaptic homeostasis and protein quality control when intense neuronal activity challenges the synaptic proteome. We identified a residue in the flexible region of EndoA (Endophilin A) that dictates calcium-dependent EndoA mobility from the plasma membrane to the cytosol, where this protein interacts with autophagic membranes to promote autophagosome formation. We discovered that a novel Parkinson’s disease-risk mutation in SH3GL2 (SH3 domain containing GRB2 like 2, endophilin A1) disrupts the calcium sensing of SH3GL2, leading to an immobile protein that cannot respond to calcium influx and therefore disrupting autophagy induction at synapses. Our work shows how neuronal activity is connected with autophagy to maintain synaptic homeostasis and survival.

Transmission of stimulus-induced epigenetic changes through cell division is coupled to continuous transcription factor activity.

Trained immunity, or innate immune memory, has been attributed to the long-term retention of stimulus-induced histone post-translational modifications (PTMs) following clearance of the initial stimulus. Yet, it remains unknown how this epigenetic memory can persist for months in dividing cells given the lack of any known mechanism for stimulus-induced histone PTMs to be directly copied from parent to daughter strand during DNA replication. Here, using time course RNA-seq, ChIP-seq, and infection assays, we find that trained macrophages are transcriptionally, epigenetically, and functionally re-programmed for at least 14 cell divisions after stimulus washout. However, the epigenetic changes observed after multiple rounds of cell division do not result from the self-sustained propagation of stimulus-induced epigenetic changes through cell division. Instead, long-lasting epigenetic differences between trained and non-trained cells are always coupled with changes in transcription factor (TF) activity, emphasizing the central role played by TFs, and gene expression changes more broadly, in driving the transmission of stimulus-induced epigenetic changes across cell divisions.

EphB2-dependent prefrontal cortex activation promotes long-range social approach and partner responsiveness

Social behavior starts with dynamic approach prior to the final consummation. The flexible processes ensure mutual feedback across social brains to transmit signals. However, how the brain responds to the initial social stimuli precisely to elicit timed behaviors remains elusive. Here, by using real-time calcium recording, we identify the abnormalities of EphB2 mutant with autism-associated Q858X mutation in processing long-range approach and accurate activity of prefrontal cortex (dmPFC). The EphB2-dependent dmPFC activation precedes the behavioral onset and is actively associated with subsequent social action with the partner. Furthermore, we find that partner dmPFC activity is responsive coordinately to the approaching WT mouse rather than Q858X mutant mouse, and the social defects caused by the mutation are rescued by synchro-optogenetic activation in dmPFC of paired social partners. These results thus reveal that EphB2 sustains neuronal activation in the dmPFC that is essential for the proactive modulation of social approach to initial social interaction.