Background: During neuromuscular junction (NMJ) development, synapses are produced in excess. By sensing the activity-dependent release of ACh, adenosine, and neurotrophins, presynaptic receptors prompt axonal competition and loss of the unnecessary axons. The receptor action is mediated by synergistic and antagonistic relations when they couple to downstream kinases (mainly protein kinases A and C (PKA and PKC)), which phosphorylate targets involved in axonal disconnection. Here, we directly investigated the involvement of PKA subunits and PKC isoforms in synapse elimination.
Methods: Selective PKA and PKC peptide modulators were applied daily to the Levator auris longus (LAL) muscle surface of P5-P8 transgenic B6.Cg-Tg (Thy1-YFP) 16 Jrs/J (and also C57BL/6J) mice, and the number of axons and the postsynaptic receptor cluster morphology were evaluated in P9 NMJ.
Results: PKA (PKA-I and PKA-II isozymes) acts at the pre- and postsynaptic sites to delay both axonal elimination and nAChR cluster differentiation, PKC activity promotes both axonal loss (a cPKCβI and nPKCε isoform action), and postsynaptic nAChR cluster maturation (a possible role for PKCθ). Moreover, PKC-induced changes in axon number indirectly influence postsynaptic maturation.
Conclusions: PKC and PKA have opposed actions, which suggests that changes in the balance of these kinases may play a major role in the mechanism of developmental synapse elimination.
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http://dx.doi.org/10.3390/cells8111304 | DOI Listing |
Cells
December 2024
Laboratory of Cardiovascular Science, Intramural Research Program, National Institute on Aging, National Institute of Health, Baltimore, MD 21224, USA.
The spontaneous firing of the sinoatrial (SA) node, the physiological pacemaker of the heart, is generated within sinoatrial nodal cells (SANCs) and is regulated by a "coupled-clock" pacemaker system, which integrates a "membrane clock", the ensemble of ion channel currents, and an intracellular "Ca clock", sarcoplasmic reticulum-generated local submembrane Ca releases via ryanodine receptors. The interactions within a "coupled-clock" system are modulated by phosphorylation of surface membrane and sarcoplasmic reticulum proteins. Though the essential role of a high basal cAMP level and PKA-dependent phosphorylation for basal spontaneous SANC firing is well recognized, the role of basal CaMKII-dependent phosphorylation remains uncertain.
View Article and Find Full Text PDFNeuropsychologia
January 2025
Department of Criminology & Gonda Multidisciplinary Brain Research Center, Bar-Ilan University, Ramat Gan 5290002, Israel; Department of Neuroscience and Biomedical Engineering, Aalto University, Finland 00076. Electronic address:
While decreasing negative attitudes against outgroups are often reported by individuals themselves, biased behaviour prevails. This gap between words and actions may stem from unobtrusive mental processes that could be uncovered by using neuroimaging in addition to self-reports. In this study we investigated whether adding neuroimaging to a traditional intergroup bias measure could detect intersubject differences in intergroup bias processes in a societal context where opposing discrimination is normative.
View Article and Find Full Text PDFBackground: Extracellular vesicles (EVs) are lipid bilayer nanoparticles (30-10,000 nm) released from all cells that facilitate cell-to-cell communication. Cell type-specific EVs can be enriched using cell-specific surface markers. Neuronal-enriched EVs (NEVs) contain measurable neurotrophins, pro- and mature brain-derived neurotrophic factor (BDNF), that have opposing action in neuronal plasticity.
View Article and Find Full Text PDFAlzheimers Dement
December 2024
Dementia Research Centre, UCL Queen Square Institute of Neurology, London, United Kingdom.
The recent positive phase 3 clinical trials of new treatments and their licensing and roll-out in the US and other countries represents a major turning point in Alzheimer's disease research. As has been the case with many other diseases, e.g.
View Article and Find Full Text PDFJ Med Internet Res
January 2025
Faculty of Health and Life Sciences, University of Exeter, Exeter, United Kingdom.
Background: Extended reality (XR) technologies are increasingly being used to reduce health and procedural anxieties. The global effectiveness of these interventions is uncertain, and there is a lack of understanding of how patient outcomes might vary between different contexts and modalities.
Objective: This research used panoramic meta-analysis to synthesize evidence across the diverse clinical contexts in which XR is used to address common outcomes of health and procedural anxiety.
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