Hypothesis Relating the Structure, Biochemistry and Function of Active Zone Material Macromolecules at a Neuromuscular Junction

This report integrates knowledge of in situ macromolecular structures and synaptic protein biochemistry to propose a unified hypothesis for the regulation of certain vesicle trafficking events (i.e., docking, priming, Ca2+-triggering, and membrane fusion) that lead to neurotransmitter secretion from specialized “active zones” of presynaptic axon terminals. Advancements in electron tomography, to image tissue sections in 3D at nanometer scale resolution, have led to structural characterizations of a network of different classes of macromolecules at the active zone, called “Active Zone Material’. At frog neuromuscular junctions, the classes of Active Zone Material macromolecules “top-masts”, “booms”, “spars”, “ribs” and “pins” direct synaptic vesicle docking while “pins”, “ribs” and “pegs” regulate priming to influence Ca2+-triggering and membrane fusion. Other classes, “beams”, “steps”, “masts”, and “synaptic vesicle luminal filaments’ likely help organize and maintain the structural integrity of active zones. Extensive studies on the biochemistry that regulates secretion have led to comprehensive characterizations of the many conserved proteins universally involved in these trafficking events. Here, a hypothesis including a partial proteomic atlas of Active Zone Material is presented which considers the common roles, binding partners, physical features/structure, and relative positioning in the axon terminal of both the proteins and classes of macromolecules involved in the vesicle trafficking events. The hypothesis designates voltage-gated Ca2+ channels and Ca2+-gated K+ channels to ribs and pegs that are connected to macromolecules that span the presynaptic membrane at the active zone. SNARE proteins (Syntaxin, SNAP25, and Synaptobrevin), SNARE-interacting proteins Synaptotagmin, Munc13, Munc18, Complexin, and NSF are designated to ribs and/or pins. Rab3A and Rabphillin-3A are designated to top-masts and/or booms and/or spars. RIM, Bassoon, and Piccolo are designated to beams, steps, masts, ribs, spars, booms, and top-masts. Spectrin is designated to beams. Lastly, the luminal portions of SV2 are thought to form the bulk of the observed synaptic vesicle luminal filaments. The goal here is to help direct future studies that aim to bridge Active Zone Material structure, biochemistry, and function to ultimately determine how it regulates the trafficking events in vivo that lead to neurotransmitter secretion.

NEUROPROTECTIVE ACTIVITY OF EXTRACT OF CELERY (APIUM GRAVEOLENS) IN INSILICO STUDY

Backround: Celery (Apium graveolens L., Apiaceae) is one of the medicinal plants with secondary metabolite components that have pharmacological effects such as vitamin (choline) content. This study aims to evaluate the mechanism and interaction of choline contained in celery on its effectiveness as a neuroprotective. Methods: This research is an experimental research using the in silico study. Results: The insilico search found that the choline content in celery binds to Slc5a7, Chat and Ache. Which has a function in the process of neurotransmitter biosynthesis, neurotransmitter metabolic processes and neurotransmitter secretion processes Conclusion: The celery (Apium graveolens L., Apiaceae) have pharmacological activity as neuroprotective through the interaction of Slc5a7, Chat and Ache

A diet high in sugar and fat influences neurotransmitter metabolism and then affects brain function by altering the gut microbiota

Gut microbiota (GM) metabolites can modulate the physiology of the host brain through the gut–brain axis. We wished to discover connections between the GM, neurotransmitters, and brain function using direct and indirect methods. A diet with increased amounts of sugar and fat (high-sugar and high-fat (HSHF) diet) was employed to disturb the host GM. Then, we monitored the effect on pathology, neurotransmitter metabolism, transcription, and brain circularRNAs (circRNAs) profiles in mice. Administration of a HSHF diet-induced dysbacteriosis, damaged the intestinal tract, changed the neurotransmitter metabolism in the intestine and brain, and then caused changes in brain function and circRNA profiles. The GM byproduct trimethylamine-n-oxide could degrade some circRNAs. The basal level of the GM decided the conversion rate of choline to trimethylamine-n-oxide. A change in the abundance of a single bacterial strain could influence neurotransmitter secretion. These findings suggest that a new link between metabolism, brain circRNAs, and GM. Our data could enlarge the “microbiome–transcriptome” linkage library and provide more information on the gut–brain axis. Hence, our findings could provide more information on the interplay between the gut and brain to aid the identification of potential therapeutic markers and mechanistic solutions to complex problems encountered in studies of pathology, toxicology, diet, and nutrition development.

Melatonin Regulates the Neurotransmitter Secretion Disorder Induced by Caffeine Through the Microbiota-Gut-Brain Axis in Zebrafish (Danio rerio)

Melatonin has been widely used as a “probiotic agent” capable of producing strong neurotransmitter secretion regulatory effects, and the microbiota-gut-brain axis-related studies have also highlighted the role of the gut microbiota in neuromodulation. In the present study, a zebrafish neural hyperactivity model was established using caffeine induction to explore the regulatory effects of melatonin and probiotic on neurotransmitter secretion disorder in zebrafish. Disorders of brain neurotransmitter secretion (dopamine, γ-aminobutyric acid, and 5-hydroxytryptamine) caused by caffeine were improved after interference treatment with melatonin or probiotic. Shotgun metagenomic sequencing demonstrated that the melatonin-treated zebrafish gradually restored their normal intestinal microbiota and metabolic pathways. Germ-free (GF) zebrafish were used to verify the essential role of intestinal microbes in the regulation of neurotransmitter secretion. The results of the neurotransmitter and short-chain fatty acid determination revealed that the effect on the zebrafish in the GF group could not achieve that on the zebrafish in the melatonin group after adding the same dose of melatonin. The present research revealed the potential mode of action of melatonin through the microbiota-gut-brain axis to regulate the disruption of neurotransmitter secretion, supporting the future development of psychotropic drugs targeting the intestinal microbiota.

Quantifying neurotransmitter secretion at single-vesicle resolution using high-density complementary metal–oxide–semiconductor electrode array

Neuronal exocytosis facilitates the propagation of information through the nervous system pertaining to bodily function, memory, and emotions. Using amperometry, the sub-millisecond dynamics of exocytosis can be monitored and the modulation of exocytosis due to drug treatment or neurodegenerative diseases can be studied. Traditional single-cell amperometry is a powerful technique for studying the molecular mechanisms of exocytosis, but it is both costly and labor-intensive to accumulate statistically significant data. To surmount these limitations, we have developed a silicon-based electrode array with 1024 on-chip electrodes that measures oxidative signal in 0.1 millisecond intervals. Using the developed device, we are able to capture the modulation of exocytosis due to Parkinson’s disease treatment (L-Dopa), with statistical significance, within 30 total minutes of recording. The validation study proves our device’s capability to accelerate the study of many pharmaceutical treatments for various neurodegenerative disorders that affect neurotransmitter secretion to a matter of minutes.

Melatonin regulates the neurotransmitter secretion disorder induced by caffeine through the gut-brain axis in zebrafish (Danio rerio)

Background: Melatonin has been widely used as a "probiotic agent" capable of producing strong neurotransmitter secretion regulatory effects. The probiotics related researches also provide the evidence of microbial interactions with the gut-brain axis for mental health. In the present study, a zebrafish neural hyperactivity model was established using caffeine induction, and the regulation and mechanism of melatonin and probiotic on zebrafish neurotransmitter secretion disorder were explored. To further address the challenge that if the gut microbes play an essential role in the regulation of neurotransmitter secretion disorder via a process that involves melatonin, the Germ-free (GF) zebrafish model was used to verify the hypothesis. Results: Disorders of brain neurotransmitter secretion caused by caffeine, including that of dopamine (DA), γ-aminobutyric acid (γ-GABA), and 5-hydroxytryptamine (5-HT), were improved after interference treatment with melatonin or the probiotic. Metagenomic sequencing demonstrated that the melatonin-treated zebrafish gradually restored their normal intestinal microbial structure, while probiotic supplementation may restructure a new microbiome. Additionally, supplementation with melatonin significantly regulated intestinal microbial functional features, which indicated the gut microbiota plays the key role in the function of melatonin. Based on this activity, a Germ-free zebrafish model was applied to verified our hypothesis in the following validation experiment. Validation experiment results revealed that the effect on the zebrafish in the GF group could not achieve that on the zebrafish in the melatonin group after adding the same dose of melatonin, and subsequent real-time PCR and metabolic pathway analysis confirmed the conclusion. Meanwhile, the content of acetic acid and propionic acid in the gut of not-germ-free zebrafish decreased after caffeine induction and increased significantly after melatonin treatment. However, no acetic or propionic acids were found, detected, changed as there are germ-free zebrafish. Conclusions: In the present research, we identified the potential mechanism of melatonin regulation of neurotransmitter secretion disorder through the gut-brain axis, laying a foundation for exploring the prevention and treatment of some neuropsychiatric disorders by improving the intestinal microbiota.

Effect of Bortezomib on Global Gene Expression in PC12-Derived Nerve Cells

Peripheral neuropathy is one of the main side-effects of novel therapeutics used in oncohematological diseases, but the molecular basis underlying its development and progression as well as neurotoxicity mechanisms induced by the use of these therapeutics are still not fully elucidated. The aim of this study was to demonstrate the effect of bortezomib on global gene and miRNA expression on PC12-derived nerve cells. Microarray analysis showed that expression of 1383 genes was downregulated at least two fold and 671 genes were upregulated at least two fold in PC12-derived nerve cells treated with bortezomib compared to untreated/control cells. Analysis of functional annotations mainly identified downregulated processes (e.g., regulation of cell cycle, DNA replication and repair, regulation of cell migration, neuron projection morphogenesis and neurotransmitter secretion). The result of miRNA expression analysis demonstrated only 11 significantly downregulated miRNAs (at least two fold) in bortezomib-treated PC12-derived nerve cells vs. control cells. MiRNAs regulate gene expression, therefore we decided to conduct an analysis comparing the outcomes of miRNA microarray expression data to the obtained mRNA data. The most interesting miRNA–target gene correlation is downregulated expression of miR-130a-3p and miR-152-3p and as a result of this downregulation the expression of the Gadd45 increased. This gene is a member of a group of genes, the transcript expression of which is enhanced after stressful growth arrest conditions and treatment with DNA-damaging agents like drugs or mutagens.

Melatonin regulates the neurotransmitter secretion disorder induced by caffeine through the gut-brain axis in zebrafish (Danio rerio)

Background : Melatonin has been widely used as a "probiotic agent" capable of producing strong neurotransmitter secretion regulatory effects. In the present study, a zebrafish neural hyperactivity model was established using caffeine induction, and the regulation and mechanism of melatonin and probiotic on zebrafish neurotransmitter secretion disorder were explored. Results : Disorders of brain neurotransmitter secretion caused by caffeine, including that of dopamine (DA), γ-aminobutyric acid (γ-GABA), and 5-hydroxytryptamine (5-HT), were improved after interference treatment with melatonin or the probiotic. Metagenomic sequencing demonstrated that the melatonin-treated zebrafish gradually restored their normal intestinal microbial structure, while probiotic supplementation may restructure a new microbiome. Additionally, supplementation with melatonin significantly regulated intestinal microbial functional features. Based on this activity, we supposed that gut microbes play an essential role in the regulation of neurotransmitter secretion disorder via a process that involves melatonin. Germ-free (GF) zebrafish were used to verify the hypotheses. Validation experiment results revealed that the effect on the zebrafish in the GF group could not achieve that on the zebrafish in the melatonin group after adding the same dose of melatonin, and subsequent real-time PCR and metabolic pathway analysis confirmed the conclusion. Meanwhile, the content of acetic acid and propionic acid in the zebrafish gut decreased after caffeine induction and increased significantly after melatonin treatment. Conclusions : In the present research, we identified the potential mechanism of melatonin regulation of neurotransmitter secretion disorder through the gut-brain axis, laying a foundation for exploring the prevention and treatment of some neuropsychiatric disorders by improving the intestinal microbiota.