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Neurourology
Published in Manit Arya, Taimur T. Shah, Jas S. Kalsi, Herman S. Fernando, Iqbal S. Shergill, Asif Muneer, Hashim U. Ahmed, MCQs for the FRCS(Urol) and Postgraduate Urology Examinations, 2020
Onabotulinum toxin A was first used in 1988 for the treatment of detrusor-sphincter dyssynergia. The first report for neurogenic detrusor overactivity was by Schurch in 2000. It is a selective inhibitor of presynaptic vesicular acetylcholine release by cleaving the synaptosomal-associated protein 25 (SNAP-25). The effects are temporary lasting on an average of 6–9 months. Re-injections are equally effective. It is generally performed under local anaesthesia with a flexible cystoscope as a day case procedure. Whilst originally licensed in the UK for use in neurogenic detrusor overactivity, in 2019 it was licensed for use in idiopathic detrusor overactivity (NICE).
Homeostasis of Dopamine
Published in Nira Ben-Jonathan, Dopamine, 2020
The SNARE complex is formed by members of the synaptosomal-associated protein 25 (SNAP-25), vesicle-associated membrane protein (VAMP) and members of the syntaxins family. Interactions between these proteins create a four-helix bundle, formed by two helices of SNAP-25, one vesicular-transmembrane VAMP and one presynaptic plasma membrane syntaxin that brings together the vesicular and plasmatic membranes. Other proteins that interact with the SNARE complex include Munc-18, complexin, synaptophysin, and synaptotagmin [77]. In addition, synaptotagmin serves as a calcium sensor and regulates the SNARE zipping. The SM proteins are evolutionary conserved cytosolic proteins that serve as essential partners for SNARE proteins in fusion. Among these is Munc 18, which primarily interacts with syntaxin-1 and whose function is tightly regulated by calcium.
Micronutrients for Improved Management of Huntington’s Disease
Published in Kedar N. Prasad, Micronutrients in Health and Disease, 2019
Post-translational modification of proteins by the lipid palmitate is needed for the correct targeting and functioning of certain proteins, including huntingtin protein. Palmitoylation of proteins is regulated by two functionally opposing enzymes palmitoyl acyltransferases, which add palmitate to proteins, and acyl protein thioesterases, which remove palmitate from proteins. This process of palmitate is important for the development of synapses and synaptic activity in the brain. Wild-type huntingtin protein is palmitoylated by huntingtin-interacting protein-14 (HIP-14), which exhibits palmitate acyltransferase activity.61 If the interaction between HD protein and HIP-14 is reduced, the palmitoylation of HD protein is decreased leading to increased protein aggregations and neuronal toxicity. Conversely, overexpression of HIP-14 can increase palmitoylation and this markedly reduced HD protein aggregation. This study suggests that palmitoylation by HIP-14 plays a role in the pathogenesis of HD. This was further supported by the study in which deletion of HIP-14 caused development of HD pathology and behavioral features in mice.62 Huntingtin-interacting protein-14 like (HIP-14L) is a paralog (as a result of gene duplication that may acquire different function) of HIP-14. Both HIP-14 and HIP-14L are essential for palmitoylation of huntingtin protein. HIP-14L-deficient mice have reduced palmitoylation of the HIP-14L substrate SNAP25 (synaptosomal-associated protein-25), early onset of motor deficits, and widespread and progressive neurodegeneration in the brain.63
Investigation of possible associations of the BDNF, SNAP-25 and SYN III genes with the neurocognitive measures: BDNF and SNAP-25 genes might be involved in attention domain, SYN III gene in executive function
Published in Nordic Journal of Psychiatry, 2022
Hilmi Bolat, Gül Ünsel-Bolat, Semiha Özgül, Erhan Parıltay, Akın Tahıllıoğlu, Luis Augusto Rohde, Haluk Akın, Eyüp Sabri Ercan
In the same line with BDNF gene, there are conflicting results about the association of Synaptosomal-Associated Protein 25 (SNAP25) and Synapsin III (SYN III) genes and ADHD diagnosis [8,12–18]. The SNAP25 gene is encoding a protein that is responsible for the release of neurotransmitters by vesicle fusion. Also, the SNAP25 gene was implicated in neuronal growth, differentiation, neurotransmitter release and synaptic plasticity which are underlying processes of attention, memory, learning and other cognitive processes [19]. The major variants studied were rs362987 (intron 4), rs363006 (intron 6), rs3746544 (3′-UTR), and rs1051312 (3′-UTR) [8]. The main effect on ADHD susceptibility was observed especially with the rs3746544 variant [8]. Liu et al. conducted a meta-analysis and found that both rs3746544 and rs1051312 polymorphisms may have possibly higher odds of developing ADHD [20]. Also, there are studies that report SNAP25 gene polymorphisms are associated with adult ADHD diagnosis, not childhood ADHD [21]. Synapsins are neuronal vesicle proteins and SYNIII gene is encoding a protein that is especially responsible for synaptic transmission of dopamine [22].
The role of synaptic biomarkers in the spectrum of neurodegenerative diseases
Published in Expert Review of Proteomics, 2020
Sonia Mazzucchi, Giovanni Palermo, Nicole Campese, Alessandro Galgani, Alessandra Della Vecchia, Andrea Vergallo, Gabriele Siciliano, Roberto Ceravolo, Harald Hampel, Filippo Baldacci
Synapses are the essential component of neural networks and allow transfer and storage of information [3]. The information is transferred from pre-synaptic to post-synaptic neurons by the release of neurotransmitters within the synaptic cleft. Proteins belonging to the so-called SNARE complex tune this vesicle trafficking [4]; these include the synaptosomal-associated protein 25 (SNAP-25), a key adhesion molecule for vesicle docking, trafficking, and exocytosis, whose activity is modulated by synaptotagmin 1 (SYT-1), a pre-synaptic calcium sensor (Figure 1). Neurotransmitters released in the synaptic cleft bind post-synaptic receptors, thus activating downstream intracellular signal pathways. Several post-synaptic proteins further modulate these signals, including Neurogranin (Ng), a protein largely expressed in the dendritic spines of excitatory neurons of the cerebral cortex and of hippocampus [5,6]. Ng is a key modulator of Long-Term Potentiation (LTP), a mechanism largely depending on calcium signaling [7,8] (Figure 1).