In a latest research revealed within the PNAS Journal, a bunch of researchers investigated the function of micro-ribonucleic acid (miRNA) miR-335-5p as a possible therapeutic goal for epilepsy by regulating neuronal excitability by means of the modulation of voltage-gated sodium channels (VGSCs).
Study: MicroRNA-335-5p suppresses voltage-gated sodium channel expression and could also be a goal for seizure management. Image Credit: SewCreamStudio/Shutterstock.com
Background
Epilepsy impacts thousands and thousands of people worldwide, and present antiseizure drugs (ASMs) goal VGSCs. However, some types of epilepsy, like Dravet syndrome, are treatment-resistant on account of lack of VGSC perform. To develop higher therapies, researchers are exploring miRNAs that regulate gene expression.
MiRNAs can management VGSC expression, making them enticing therapeutic targets. Triangulating miRNA datasets and learning miRNA alterations attributable to efficient ASMs may reveal potential therapeutic miRNAs for epilepsy.
Cannabidiol (CBD), permitted for treatment-resistant epilepsy, is an instance of an efficient ASM with an unknown mechanism of motion, arising the necessity for additional investigation.
About the research
The research centered on investigating epilepsy utilizing animal fashions. Animals had been stored in managed circumstances with a 12-hour light-dark cycle, correct temperature, and humidity, with meals and water freely obtainable.
The researchers used two epilepsy fashions: the PPS mannequin of temporal lobe epilepsy (TLE) in rats and the pentylenetetrazol (PTZ) mannequin in mice. For the perforant path stimulation (PPS) mannequin, electrodes had been implanted, and seizures had been induced utilizing paired-pulse stimuli. For the PTZ mannequin, mice acquired a convulsant dose of PTZ to set off seizures.
Various therapies had been administered to analyze their results on epilepsy. They modulated miRNA by means of antisense oligonucleotide “antimir” injections and viral particles expressing particular miRNAs. Additionally, they administered CBD, a compound derived from hashish, to check its potential results on epilepsy.
The researchers analyzed miRNA and mRNA expression within the mind tissues of the animals. They additionally recognized miRNA-target interactions and carried out pathway enrichment analyses to know the molecular mechanisms concerned in epilepsy.
Finally, ex vivo electrophysiological recordings and sodium currents (INa) recordings in human-induced pluripotent stem cell-derived neurons had been performed to check the results of miRNA manipulation.
All experimental procedures, such because the European Communities Council Directive (2010/63/EU), adhered to moral tips.
Study outcomes
This research centered on miR-335-5p as a possible therapeutic goal for treatment-resistant epilepsy. They used a triangulation method, combining information from completely different datasets to determine miRNAs related to epilepsy.
MiR-335-5p stood out because it was constantly altered in rat hippocampal subfields, human plasma samples, and after therapy with CBD in mice.
To higher perceive the useful function of miR-335-5p, the researchers investigated its targets. They discovered that miR-335-5p regulates a number of genes encoding for VGSCs, together with sodium voltage-gated channel alpha subunit 1 (SCN1A), sodium voltage-gated channel alpha subunit 2 (SCN2A), and sodium voltage-gated channel alpha subunit 3 (SCN3A), that are essential for neuronal excitability.
Pathway enrichment evaluation revealed that lots of the targets of miR-335-5p are concerned in pathways associated to neuronal excitability, additional supporting its potential function in epilepsy.
The authors used human induced pluripotent stem cell (iPSC)-derived neurons to validate the findings in human brain-relevant fashions. Inhibition of miR-335-5p in these neurons resulted in an upregulation of VGSCs, confirming the regulatory function of miR-335-5p in human neuronal excitability.
Further, inhibiting miR-335-5p elevated seizure susceptibility, whereas overexpressing miR-335-5p utilizing viral vectors diminished seizure severity and elevated survival in response to seizures induced by PTZ.
Researchers discovered that the behavioral exams confirmed no antagonistic results of miR-335-5p modulation on cognition or naturalistic conduct in mice, indicating its potential security as a therapeutic goal.
Discussion
In this research, researchers utilized a mixture of model-based, drug-altered, and human epilepsy biomarker datasets to determine miRNAs that regulate neuronal excitability, which may very well be related for seizure management.
Their method, often called triangulation, led them to concentrate on miR-335-5p, a miRNA primarily discovered within the mind. This method supplied further miRNA targets for epilepsy therapy in comparison with different strategies.
MiR-335-5p was not initially thought-about a number one candidate when solely animal mannequin miRNA profiles had been examined, underscoring the significance of together with human information and numerous sources of miRNA profiling. Interestingly, miR-335-5p ranges appeared to range amongst completely different fashions, which can be associated to temporal and activity-dependent adjustments in miRNA expression.
The researchers discovered that miR-335-5p performs a job in regulating the expression of VGSCs, that are essential for neuronal excitability.
Inhibiting miR-335-5p elevated VGSC ranges and pyramidal neuron excitability in mice whereas overexpressing it had the alternative impact, lowering seizure severity. These findings counsel that miR-335-5p may very well be a possible therapeutic goal for modulating neuronal excitability in epilepsy.
Moreover, the research demonstrated that miR-335-5p modulation didn’t adversely have an effect on cognition or pure conduct in mice, indicating its potential security as a therapeutic method.
Conclusions
To summarize, researchers discovered that concentrating on miR-335-5p may probably develop new therapies for epilepsy, because it may affect VGSCs and fine-tune neuronal excitability, offering a bidirectional impact that is likely to be useful in several types of epilepsy.
However, additional analysis is required to know the complete extent of miR-335-5p’s function and its potential as a therapeutic technique for epilepsy and different neurological problems.