Forgetting as a form of adaptive engram cell plasticity.

One leading hypothesis suggests that memories are stored in ensembles of neurons (or 'engram cells') and that successful recall involves reactivation of these ensembles. A logical extension of this idea is that forgetting occurs when engram cells cannot be reactivated. Forms of 'natural forgetting' vary considerably in terms of their underlying mechanisms, time course and reversibility. However, we suggest that all forms of forgetting involve circuit remodelling that switches engram cells from an accessible state (where they can be reactivated by natural recall cues) to an inaccessible state (where they cannot). In many cases, forgetting rates are modulated by environmental conditions and we therefore propose that forgetting is a form of neuroplasticity that alters engram cell accessibility in a manner that is sensitive to mismatches between expectations and the environment. Moreover, we hypothesize that disease states associated with forgetting may hijack natural forgetting mechanisms, resulting in reduced engram cell accessibility and memory loss.

Hijacking the Hijackers: Escherichia coli Pathogenicity Islands Redirect Helper Phage Packaging for Their Own Benefit.

Phage-inducible chromosomal islands (PICIs) represent a novel and universal class of mobile genetic elements, which have broad impact on bacterial virulence. In spite of their relevance, how the Gram-negative PICIs hijack the phage machinery for their own specific packaging and how they block phage reproduction remains to be determined. Using genetic and structural analyses, we solve the mystery here by showing that the Gram-negative PICIs encode a protein that simultaneously performs these processes. This protein, which we have named Rpp (for redirecting phage packaging), interacts with the phage terminase small subunit, forming a heterocomplex. This complex is unable to recognize the phage DNA, blocking phage packaging, but specifically binds to the PICI genome, promoting PICI packaging. Our studies reveal the mechanism of action that allows PICI dissemination in nature, introducing a new paradigm in the understanding of the biology of pathogenicity islands and therefore of bacterial pathogen evolution.

Amnesia after Repeated Head Impact Is Caused by Impaired Synaptic Plasticity in the Memory Engram.

Subconcussive head impacts are associated with the development of acute and chronic cognitive deficits. We recently reported that high-frequency head impact (HFHI) causes chronic cognitive deficits in mice through synaptic changes. To better understand the mechanisms underlying HFHI-induced memory decline, we used TRAP2/Ai32 transgenic mice to enable visualization and manipulation of memory engrams. We labeled the fear memory engram in male and female mice exposed to an aversive experience and subjected them to sham or HFHI. Upon subsequent exposure to natural memory recall cues, sham, but not HFHI, mice successfully retrieved fearful memories. In sham mice the hippocampal engram neurons exhibited synaptic plasticity, evident in amplified AMPA:NMDA ratio, enhanced AMPA-weighted tau, and increased dendritic spine volume compared with nonengram neurons. In contrast, although HFHI mice retained a comparable number of hippocampal engram neurons, these neurons did not undergo synaptic plasticity. This lack of plasticity coincided with impaired activation of the engram network, leading to retrograde amnesia in HFHI mice. We validated that the memory deficits induced by HFHI stem from synaptic plasticity impairments by artificially activating the engram using optogenetics and found that stimulated memory recall was identical in both sham and HFHI mice. Our work shows that chronic cognitive impairment after HFHI is a result of deficiencies in synaptic plasticity instead of a loss in neuronal infrastructure, and we can reinstate a forgotten memory in the amnestic brain by stimulating the memory engram. Targeting synaptic plasticity may have therapeutic potential for treating memory impairments caused by repeated head impacts.

The problem of immune thrombocytopenia refractory to both eltrombopag and romiplostim.

Immune thrombocytopenia refractory to multiple thrombopoietin receptor agonists remains a challenging clinical problem. This commentary discusses and contextualizes the recent report on this entity from Moulis and colleagues, and how to move forward with these patients. Commentary on: Moulis et al. Difficult-to-treat primary immune thrombocytopenia in adults: Prevalence and burden. Results from the CARMEN-France Registry. Br J Haematol 2024;204:1476-1482.

Molecular basis of cyclic tetra-oligoadenylate processing by small standalone CRISPR-Cas ring nucleases.

Standalone ring nucleases are CRISPR ancillary proteins, which downregulate the immune response of Type III CRISPR-Cas systems by cleaving cyclic oligoadenylates (cA) second messengers. Two genes with this function have been found within the Sulfolobus islandicus (Sis) genome. They code for a long polypeptide composed by a CARF domain fused to an HTH domain and a short polypeptide constituted by a CARF domain with a 40 residue C-terminal insertion. Here, we determine the structure of the apo and substrate bound states of the Sis0455 enzyme, revealing an insertion at the C-terminal region of the CARF domain, which plays a key role closing the catalytic site upon substrate binding. Our analysis reveals the key residues of Sis0455 during cleavage and the coupling of the active site closing with their positioning to proceed with cA4 phosphodiester hydrolysis. A time course comparison of cA4 cleavage between the short, Sis0455, and long ring nucleases, Sis0811, shows the slower cleavage kinetics of the former, suggesting that the combination of these two types of enzymes with the same function in a genome could be an evolutionary strategy to regulate the levels of the second messenger in different infection scenarios.

Effects of L-Leucine Supplementation and Resistance Training on Adipokine Markers in Untrained Perimenopausal and Postmenopausal Women.

ABSTRACT: Chapman-Lopez, TJ, Funderburk, LK, Heileson, JL, Wilburn, DT, Koutakis, P, Gallucci, AR, and Forsse, JS. Effects of L-leucine supplementation and resistance training on adipokine markers in untrained perimenopausal and postmenopausal women. J Strength Cond Res 38(3): 526-532, 2024-This study examined the effects of supplementing 5 g of leucine compared with a placebo during a 10-week resistance training program on body composition parameters and adipokine concentrations in untrained, perimenopausal and postmenopausal women. Thirty-five women were randomly assigned to 2 groups-leucine (LEU, n = 17) and placebo (PLC, n = 18)-in a double-blind, placebo-controlled trial. Each group consumed the supplement or placebo every day and completed a resistance training program for 10 weeks. Using 3-day food records, a diet was assessed before the intervention and after its cessation. Body composition was assessed preintervention and postintervention using dual-energy x-ray absorptiometry. Moreover, the concentrations of adipokines, such as adiponectin, visfatin, leptin, and monocyte chemoattractant protein-1 (MCP-1), were assessed preintervention and postintervention. Both groups showed an increase in visceral adipose tissue (VAT) area ( p = 0.030) and fat-free mass (FFM; p = 0.023). There were significant group differences in concentrations of visfatin ( p = 0.020) and leptin ( p = 0.038) between the PLC and LEU groups. Visfatin displayed higher concentrations in the PLC group and leptin displayed higher concentrations in the LEU group. In addition, there were significant decreases in adiponectin concentrations for both groups (LEU: 652 ± 513 to 292 ± 447 pg·ml -1 ; PLC: 584 ± 572 to 245 ± 356 pg·ml -1 , p = 0.002) and MCP-1 only decreased in the PLC group (253 ± 119 to 206 ± 106 pg·ml -1 , p = 0.004). There were significant decreases in adiponectin concentrations in both groups and a decrease in MCP-1 concentrations in the PLC group. These decreases may be due to both adipokines possible relationship with VAT area. However, it is not known whether leucine has underlying properties that hinder changes in MCP-1 concentrations.

Age-Related Differences in Body Fat and Fitness of Firefighters Participating in a Health and Wellness Program.

ABSTRACT: Lockie, RG, Dulla, JM, Higuera, D, Ross, K, Orr, RM, Dawes, JJ, and Ruvalcaba, TJ. Age-related differences in body fat and fitness of firefighters participating in a health and wellness program. J Strength Cond Res 38(6): 1127-1135, 2024-Fitness tends to decline, whereas body fat increases, with age, which could impact firefighter occupational performance later in their careers. Health and wellness program participation could reduce these age-related changes. Archival data from 270 firefighters (258 men and 12 women) from a health and wellness program were analyzed. Data included body mass index; body fat percentage (BF%); waist circumference (WC); waist-to-hip ratio (WHR); sit and reach; grip strength; absolute and relative predicted 1 repetition maximum (1RM) leg press; crunches; push-ups; and estimated maximal aerobic capacity (V̇o2max). Firefighters were grouped by age ≤29 (n = 29); 30-34 (n = 44); 35-39 (n = 38); 40-44 (n = 39); 45-49 (n = 48); 50-54 (n = 42); and 55+ (n = 30) years. A univariate analysis of covariance, with sex as a covariate and Bonferroni's post hoc adjustment, determined between-group differences. Effect sizes (d) were calculated. Key results included that the 55+ group had higher BF% and WC compared with the 3 youngest groups (p ≤ 0.002; d = 0.86-1.08). The 50-54 group had higher BF% than the 30-34 group (p = 0.010; d = 0.77). The 55+ group had a greater WHR, lower grip strength, and completed fewer crunches and push-ups than most younger groups (p ≤ 0.05; d = 0.60-1.32). The 50-54 and 55+ groups had a lower 1RM leg press and V̇o2max compared with the younger groups (p ≤ 0.009; d = 0.77-1.79). The program appeared generally effective, with limited differences in groups below 49 years of age. Greater disparities in fat mass and fitness tended to occur in the older groups (50-54, 55+ groups). The data highlighted that older firefighters were participating in the optional program, which could lead to better health outcomes.

Cyclic Diaryl λ3-Bromanes as a Precursor for Regiodivergent Alkynylation Reactions.

Regiodivergent reactions are a fascinating tool to rapidly access molecular diversity while using identical coupling partners. We have developed a new approach for regiodivergent synthesis using the dual character of hypervalent bromines. In addition to the recently reported reactivity of hypervalent bromines as aryne precursors, the first transition metal-catalyzed reaction is reported. Accordingly, the development of these two complementary transformations allows for the alteration of regioselectivity to furnish both ortho- and meta-substituted alkynylation products. Mechanistic and computational studies show how these selectivities are controlled.

Techniques of incorporation of salty compounds, food matrix, and sodium behaviour and its effect over saltiness perception: an overview.

The salty taste is usually associated with the positively charged ion sodium present in sodium chloride. Due to its relevance in the food industry, there have been several studies to determine how this ion behaves in various food matrices, or the use of techniques to improve saltiness perception to reduce the amount necessary for savoury food. Several databases were searched, and it was discovered that sodium can interact with the protein, modifying its mobility, as well as, other components of the food matrix, such as fat, that seem to interfere with saltiness perception, increasing or reducing it. Several techniques were used to identify the interaction between sodium and the food matrix, as well as sensory testing to determine the influence of different modification strategies to enhance the saltiness perception. Due to the multiple factors involved in the salty taste, understanding the effect of the technique to modify saltiness perception, the interaction of the matrix components of the food, and the sodium interaction with those components, can be of use in the developing process of foods with a reduction in the sodium content. Supplementary Information: The online version contains supplementary material available at 10.1007/s13197-023-05861-6.

Understanding the physical basis of memory: Molecular mechanisms of the engram.

Memory, defined as the storage and use of learned information in the brain, is necessary to modulate behavior and critical for animals to adapt to their environments and survive. Despite being a cornerstone of brain function, questions surrounding the molecular and cellular mechanisms of how information is encoded, stored, and recalled remain largely unanswered. One widely held theory is that an engram is formed by a group of neurons that are active during learning, which undergoes biochemical and physical changes to store information in a stable state, and that are later reactivated during recall of the memory. In the past decade, the development of engram labeling methodologies has proven useful to investigate the biology of memory at the molecular and cellular levels. Engram technology allows the study of individual memories associated with particular experiences and their evolution over time, with enough experimental resolution to discriminate between different memory processes: learning (encoding), consolidation (the passage from short-term to long-term memories), and storage (the maintenance of memory in the brain). Here, we review the current understanding of memory formation at a molecular and cellular level by focusing on insights provided using engram technology.

The Value of Medical Innovation Versus Industry Rewards.

OBJECTIVES: This article provides systematic evidence on the share of the value of health generated by drugs and other healthcare goods and services that accrue to patients on the demand side versus the manufacturers on the supply side. METHODS: We exploit a large data set with > 9000 cost-effectiveness measures for various interventions, which we convert into measures of the shares of the value of improved health appropriated by the supply side using literature estimates of how patients value gains in health. RESULTS: We find that if patients value a quality-adjusted life-year at $450 000 the median share appropriated for drugs on the supply side is approximately 6% and has declined at 0.1% per year between 1997 and 2019. This compares with other healthcare interventions, such as screenings or medical procedures, which have a median value of 9% but decline at 0.3% per year over the same period. If patients value a quality-adjusted life-year at $150 000, the median share appropriated for drugs and other healthcare interventions on the supply side is approximately 18% and 27%, respectively. Our estimates of appropriations are upper bounds, partly due to QALYs not capturing full producer value. CONCLUSIONS: Many policy debates center on the idea that the supply side is capturing too much of the value of the medical innovation that they generate. We find that, for these interventions, a large share of the value of medical innovation accrues to patients on the demand side given that the revenue to innovators is often far less than the patient's value of these medical innovations.

Effects of Endoscopic Sinus Surgery on Olfactory Function.

PURPOSE OF REVIEW: To review the effects of endoscopic sinus surgery and endonasal approaches to the skull base on olfaction. RECENT FINDINGS: Advancements in endonasal endoscopic approaches to the sinuses and skull base allow for direct treatment of a variety of sinonasal and skull base diseases. However, these extended approaches will often require manipulation of normal anatomical structures and the olfactory neuroepithelium. Depending on the planned procedure and extent of disease, the prognosis of olfactory perception can vary significantly among patients. Endoscopic sinonasal surgical procedures may impact olfaction. Optimizing olfactory function requires proper surgical techniques, gentle handling of tissue, and perioperative care. Surgeons must discuss objectives and manage patient expectations. Routine olfactory assessment is crucial in surgical work-up and follow-up. Preserving anatomical structures while addressing the obstruction of the olfactory cleft helps to prevent decreased olfactory threshold. However, smell identification and discrimination do not always correlate with sinonasal anatomy.

The aggregate value of cancer screenings in the United States: full potential value and value considering adherence.

BACKGROUND: Although cancer mortality has been decreasing since 1991, many cancers are still not detected until later stages with poorer outcomes. Screening for early-stage cancer can save lives because treatments are generally more effective at earlier than later stages of disease. Evidence of the aggregate benefits of guideline-recommended single-site cancer screenings has been limited. This article assesses the benefits in terms of life-years gained and associated value from major cancer screening technologies in the United States. METHODS: A mathematical model was built to estimate the aggregate benefits of screenings for breast, colorectal, cervical, and lung cancer over time since the start of US Preventive Services Task Force (USPSTF) recommendations. For each type, the full potential benefits under perfect adherence and the benefits considering reported adherence rates were estimated. The effectiveness of each screening technology was abstracted from published literature on the life-years gained per screened individual. The number of individuals eligible for screening per year was estimated using US Census data matched to the USPSTF recommendations, which changed over time. Adherence rates to screening protocols were based on the National Health Interview Survey results with extrapolation. RESULTS: Since initial USPSTF recommendations, up to 417 million people were eligible for cancer screening. Assuming perfect adherence to screening recommendations, the life-years gained from screenings are estimated to be 15.5-21.3 million (2.2-4.9, 1.4-3.6, 11.4-12.3, and 0.5 million for breast, colorectal, cervical, and lung cancer, respectively). At reported adherence rates, combined screening has saved 12.2-16.2 million life-years since the introduction of USPSTF recommendations, ~ 75% of potential with perfect adherence. These benefits translate into a value of $8.2-$11.3 trillion at full potential and $6.5-$8.6 trillion considering current adherence. Therefore, single-site screening could have saved an additional 3.2-5.1 million life-years, equating to $1.7-$2.7 trillion, with perfect adherence. CONCLUSIONS: Although gaps persist between the full potential benefit and benefits considering adherence, existing cancer screening technologies have offered significant value to the US population. Technologies and policy interventions that can improve adherence and/or expand the number of cancer types tested will provide significantly more value and save significantly more patient lives.

G-Quadruplexes Regulate miRNA Biogenesis in Live Zebrafish Embryos.

RNA guanine quadruplexes (G4s) regulate RNA functions, metabolism, and processing. G4s formed within precursors of microRNAs (pre-miRNAs) may impair pre-miRNAs maturation by Dicer, thus repressing mature miRNA biogenesis. As miRNAs are essential for proper embryonic development, we studied the role of G4s on miRNA biogenesis in vivo during zebrafish embryogenesis. We performed a computational analysis on zebrafish pre-miRNAs to find putative G4 forming sequences (PQSs). The precursor of the miRNA 150 (pre-miR-150) was found to contain an evolutionarily conserved PQS formed by three G-tetrads and able to fold in vitro as G4. MiR-150 controls the expression of myb, which shows a well-defined knock-down phenotype in zebrafish developing embryos. We microinjected zebrafish embryos with in vitro transcribed pre-miR-150 synthesized using either GTP (G-pre-miR-150) or 7-Deaza-GTP, a GTP analogue unable to form G4s (7DG-pre-miR-150). Compared to embryos injected with G-pre-miR-150, embryos injected with 7DG-pre-miR-150 showed higher levels of miRNA 150 (miR-150) and lower levels of myb mRNA and stronger phenotypes associated with myb knock-down. The incubation of pre-miR-150 prior to the injection with the G4 stabilizing ligand pyridostatin (PDS) reverted gene expression variations and rescued the phenotypes related to myb knock-down. Overall, results suggest that the G4 formed in pre-miR-150 functions in vivo as a conserved regulatory structure competing with the stem-loop structure necessary for miRNA biogenesis.

Effects of Static Contemporary Western Yoga vs. a Dynamic Stretching Exercise Program on Body Composition, Balance, and Flexibility.

ABSTRACT: Chapman-Lopez, TJ, Moris, JM, Petty, G, Timon, C, and Koh, Y. Effects of static contemporary western yoga vs. a dynamic stretching exercise program on body composition, balance, and flexibility. J Strength Cond Res 37(5): 1064-1069, 2023-Essentrics is a dynamic full-body stretching workout, which has recently earned its popularity in the field of yoga because of its potential for improvement in balance, flexibility, and weight loss while adding enjoyment to the workout without any discomfort and pain. However, the effects of Essentrics on overall health have not been well studied, particularly in a younger, physically healthy population. Thirty-five subjects (27 females and 8 males, age = 20.4 ± 0.2 years, and body mass index = 22.58 ± 0.55 kg·m-2) were assigned to 2 groups-contemporary western yoga (CWY, n = 20) and Essentrics (ESS, n = 15). Each group met 3 times per week for a total of 45-50 minutes per day for 6 weeks. Anthropometric measurements, body composition (dual-energy x-ray absorptiometry), flexibility (sit-and-reach), and balance (lower extremity Y-balance) were assessed before and after the 6-week program. The balance test included 3 reaches (anterior, posteromedial [PM], and posterolateral [PL] and composite reach distance). Each reach was averaged for the right and left sides and then normalized to leg length. Data were analyzed using an analysis of variance with repeated measures (p ≤ 0.05), and a post hoc test was performed for any significant interactions. There were no significant group differences between CWY and ESS in balance and flexibility. Following the 6-week yoga programs, balance was improved as follows: PM (87.13 ± 11.64 cm to 92.25 ± 9.91 cm, p = 0.001), PL (82.88 ± 11.28 to 88.62 ± 9.62 cm, p = 0.002), composite reach distance (CRD) (225.96 ± 27.17 to 238.26 ± 22.98 cm, p = 0.001), normalized PM (98.31 ± 11.68 to 104.27 ± 11.14%, p = 0.001), normalized PL (93.60 ± 11.98 to 100.15 ± 10.70%, p = 0.001), and normalized CRD (255.12 ± 27.89 to 269.21 ± 25.07%, p = 0.001). Flexibility was also improved from 51.42 ± 8.24 to 53.38 ± 7.04 cm (p = 0.010) following the 6-week workout programs. Total body fat percentage was significantly reduced only in the CWY group (24.44 ± 6.73 to 23.51 ± 6.32%, p = 0.002). Regardless of the type of stretching workout, both dynamic and static workouts improved flexibility and balance. Thus, individuals seeking to improve balance and flexibility can benefit from either dynamic or static yoga program.

Impact of Physical Fitness on Reasons for Academy Release in Firefighter Trainees.

ABSTRACT: Lockie, RG, Orr, RM, Montes, F, Ruvalcaba, TJ, and Dawes, JJ. Impact of physical fitness on reasons for academy release in firefighter trainees. J Strength Cond Res 37(7): 1515-1522, 2023-Firefighter trainees require a certain level of fitness to be admitted to and to complete a fire training academy. There is no research detailing whether there are fitness differences between trainees who graduate (GRAD) or those released due to either injury (RELI) or skills test performance failures (RELP). Archival data from 305 trainees (274 males and 31 females) were analyzed. Trainees completed the following fitness tests at the start of academy: Illinois agility test, metronome push-ups, pull-ups, leg tucks, multistage fitness test, backward overhead medicine ball throw (BOMBT) with a 4.54-kg ball, 10 repetition maximum deadlift, and a farmer's carry with 18-kg kettlebells over a 91.44-m course. Trainees were split into GRAD (245 males and 16 females), RELI (9 males and 1 female), and RELP (20 males and 14 females) groups. Kolmogorov-Smirnov data indicated most data were not normally distributed. Accordingly, Kruskal-Wallis H-tests, with Bonferroni post hoc, calculated between-group fitness test differences. Effect sizes were also derived. Except for the leg tuck and farmer's carry, the RELP group performed significantly poorer in all fitness tests compared with the GRAD group ( p ≤ 0.032). The largest effects were seen for the BOMBT ( d = 1.02), Illinois agility test, and 10 repetition maximum deadlift (both d = 0.78). There were no significant fitness test differences for the GRAD and RELI groups. Trainees with poorer fitness were more likely to be released from academy due to skills test failures. Multiple fitness components, but particularly muscular strength and power, should be developed in trainees to aid their ability to perform academy firefighting tasks.

Comparison of chromium and cobalt serum levels between a modular neck stem and its monoblock counterpart in primary total hip arthroplasty.

BACKGROUND: The addition of junctions in modular stems implies a greater susceptibility to corrosion. PURPOSE: The aim of this study is to compare serum chromium and cobalt levels after using a bimodular stem and its monoblock counterpart in primary total hip arthroplasty. Postoperative clinical scores were also compared. PATIENTS AND METHODS: A prospective cohort study between 2012 and 2015 was designed. One arm of the cohort included patients with the cementless modular neck stem H-Max M® and the other with the cementless monoblock stem counterpart H-Max S®. RESULTS: No statistically significant difference was found in chromium value between groups (p = 0.621) at two years postoperative. Cobalt value was higher in the modular group (p = < 0.001). No statistically significant difference was found in clinical postoperative scores except for the Harris Hip Score, with better results at six months in modular group (p = 0.007). CONCLUSIONS: Higher serum cobalt level in the modular group has limited the use of modular stems in our daily practice. Advantages of modular stem were not found. LEVEL OF EVIDENCE: II.

Chronic Obstructive Pulmonary Disease Is Associated with Epigenome-Wide Differential Methylation in BAL Lung Cells.

DNA methylation patterns in chronic pulmonary obstructive disease (COPD) might offer new insights into disease pathogenesis. To assess methylation profiles in the main COPD target organ, we performed an epigenome-wide association study on BAL cells. Bronchoscopies were performed in 18 subjects with COPD and 15 control subjects (ex- and current smokers). DNA methylation was measured using the Illumina MethylationEPIC BeadChip Kit, covering more than 850,000 CpGs. Differentially methylated positions (DMPs) were examined for 1) enrichment in pathways and functional gene relationships using the Kyoto Encyclopedia of Genes and Genomes and Gene Ontology, 2) accelerated aging using Horvath's epigenetic clock, 3) correlation with gene expression, and 4) colocalization with genetic variation. We found 1,155 Bonferroni-significant (P < 6.74 × 10-8) DMPs associated with COPD, many with large effect sizes. Functional analysis identified biologically plausible pathways and gene relationships, including enrichment for transcription factor activity. Strong correlation was found between DNA methylation and chronological age but not between COPD and accelerated aging. For 79 unique DMPs, DNA methylation correlated significantly with gene expression in BAL cells. Thirty-nine percent of DMPs were colocalized with COPD-associated SNPs. To the best of our knowledge, this is the first epigenome-wide association study of COPD on BAL cells, and our analyses revealed many differential methylation sites. Integration with mRNA data showed a strong functional readout for relevant genes, identifying sites where DNA methylation might directly affect expression. Almost half of DMPs were colocated with SNPs identified in previous genome-wide association studies of COPD, suggesting joint genetic and epigenetic pathways related to disease.

FENS-Kavli Network of Excellence: Science needs strong European cohesion.

Decades of scientific collaboration have brought innovation, prosperity and wide societal benefit to Europe. However, recent political events have impacted pan-European research and collaborations, and solutions are yet to materialise. Here, we argue that a vibrant, united European Research community led by its members and independent from political bodies is needed for Europe to remain a successful, interconnected scientific hub and keep delivering globally competitive science. The Federation of European Neuroscience Societies (FENS) is in an ideal position to play a paramount role in this endeavour.

M1 and M2 mAChRs activate PDK1 and regulate PKC ßI and ε and the exocytotic apparatus at the NMJ.

Neuromuscular junctions (NMJ) regulate cholinergic exocytosis through the M1 and M2 muscarinic acetylcholine autoreceptors (mAChR), involving the crosstalk between receptors and downstream pathways. Protein kinase C (PKC) regulates neurotransmission but how it associates with the mAChRs remains unknown. Here, we investigate whether mAChRs recruit the classical PKCßI and the novel PKCε isoforms and modulate their priming by PDK1, translocation and activity on neurosecretion targets. We show that each M1 and M2 mAChR activates the master kinase PDK1 and promotes a particular priming of the presynaptic PKCßI and ε isoforms. M1 recruits both primed-PKCs to the membrane and promotes Munc18-1, SNAP-25, and MARCKS phosphorylation. In contrast, M2 downregulates PKCε through a PKA-dependent pathway, which inhibits Munc18-1 synthesis and PKC phosphorylation. In summary, our results discover a co-dependent balance between muscarinic autoreceptors which orchestrates the presynaptic PKC and their action on ACh release SNARE-SM mechanism. Altogether, this molecular signaling explains previous functional studies at the NMJ and guide toward potential therapeutic targets.