egl-4 modulates electroconvulsive seizure duration in C. elegans

Rebalancing the motor circuit restores movement in a Caenorhabditis elegans model for TDP-43 toxicity

Amyotrophic lateral sclerosis can be caused by abnormal accumulation of TAR DNA-binding protein 43 (TDP-43) in the cytoplasm of neurons. Here, we use a C. elegans model for TDP-43-induced toxicity to identify the biological mechanisms that lead to disease-related phenotypes. By applying deep behavioral phenotyping and subsequent dissection of the neuromuscular circuit, we show that TDP-43 worms have profound defects in GABA neurons. Moreover, acetylcholine neurons appear functionally silenced. Enhancing functional output of repressed acetylcholine neurons at the level of, among others, G-protein-coupled receptors restores neurotransmission, but inefficiently rescues locomotion. Rebalancing the excitatory-to-inhibitory ratio in the neuromuscular system by simultaneous stimulation of the affected GABA- and acetylcholine neurons, however, not only synergizes the effects of boosting individual neurotransmitter systems, but instantaneously improves movement. Our results suggest that interventions accounting for the altered connectome may be more efficient in restoring motor function than those solely focusing on diseased neuron populations.

Roundup and glyphosate's impact on GABA to elicit extended proconvulsant behavior in Caenorhabditis elegans

As 3 billion pounds of herbicides are sprayed over farmlands every year, it is essential to advance our understanding how pesticides may influence neurological health and physiology of both humans and other animals. Studies are often one-dimensional as the majority examine glyphosate by itself. Farmers and the public use commercial products, like Roundup, containing a myriad of chemicals in addition to glyphosate. Currently, there are no neurological targets proposed for glyphosate and little comparison to Roundup. To investigate this, we compared how glyphosate and Roundup affect convulsant behavior in C.elegans and found that glyphosate and Roundup increased seizure-like behavior. Key to our initial hypothesis, we found that treatment with an antiepileptic drug rescued the prolonged convulsions. We also discovered over a third of nematodes exposed to Roundup did not recover from their convulsions, but drug treatment resulted in full recovery. Notably, these effects were found at concentrations that are 1,000-fold dilutions of previous findings of neurotoxicity, using over 300-fold less herbicide than the lowest concentration recommended for consumer use. Exploring mechanisms behind our observations, we found significant evidence that glyphosate targets GABA-A receptors. Pharmacological experiments which paired subeffective dosages of glyphosate and a GABA-A antagonist yielded a 24% increase in non-recovery compared to the antagonist alone. GABA mutant strain experiments showed no effect in a GABA-A depleted strain, but a significant, increased effect in a glutamic acid decarboxylase depleted strain. Our findings characterize glyphosate’s exacerbation of convulsions and propose the GABA-A receptor as a neurological target for the observed physiological changes. It also highlights glyphosate’s potential to dysregulate inhibitory neurological circuits.

Systematic elucidation of the pharmacological mechanisms of Rhynchophylline for treating epilepsy via network pharmacology

Background

Epilepsy, one of the most common neurological disorders, affects over 70 million people worldwide. Rhynchophylline displays a wide variety of pharmacologic actives. However, the pharmacologic effects of rhynchophylline and its mechanisms against epilepsy have not been systematically elucidated.

Methods

The oral bioavailability and druglikeness of rhynchophylline were evaluated using the Traditional Chinese Medicine Systems Pharmacology Database. Rhynchophylline target genes to treat epilepsy were identified using PharmMapper, SwissTargetPrediction and DrugBank databases integration. Protein-protein interaction analysis was carried out by utilizing the GeneMANIA database. WebGestalt was employed to perform Gene ontology and Kyoto Encyclopedia of Genes and Genomes pathway enrichment analyses. The drug-disease-target-Gene Ontology-pathway network was constructed using Cytoscape.

Results

The oral bioavailability and druglikeness of rhynchophylline were calculated to be 41.82% and 0.57, respectively. A total of 20 rhynchophylline target genes related to epilepsy were chosen. Among the 20 genes and their interacting genes, 54.00% shared protein domains and 16.61% displayed co-expression characteristics. Gene ontology, Kyoto Encyclopedia of Genes and Genomes and network analyses illustrate that these targets were significantly enriched in regulation of sensory perception, morphine addiction, neuroactive ligand-receptor interaction and other pathways or biological processes.

Conclusion

In short, rhynchophylline targets multiple genes or proteins, biological processes and pathways. It shapes a multiple-layer network that exerts systematic pharmacologic activities on epilepsy.