Hippocampus RNA Sequencing of Pentylenetetrazole-Kindled Rats and Upon Treatment of Novel Chemical Q808

Pharmacokinetic study of Q808 in rhesus monkey using liquid chromatography-tandem mass spectrometry

Background

Q808 is a novel antiepileptic agent currently in development. In this study, we established and validated a LC-MS/MS method for the quantification of Q808 in Rhesus monkey plasma. Furthermore, we applied this method to investigate the pharmacokinetics of Q808 in Rhesus monkeys.

Methods

Samples containing diazepam as an internal standard (IS) were subjected to liquid-liquid extraction (LLE) and separated using a Zorbax Extend C18 column. The detection of Q808 and IS was performed using multiple reaction monitoring mode (MRM), specifically monitoring precursor-to-product ion transitions at m/z 297.9 to 213.9 and m/z 285.2 to 193.1 for Q808 and IS, respectively. For the pharmacokinetic study of Q808, a total of 30 healthy Rhesus monkeys (half male and half female) were administered single oral doses, single IV doses, or multiple oral doses of Q808. Blood samples were collected at predetermined time points for subsequent pharmacokinetic analysis.

Results

The developed LC-MS/MS method exhibited linearity within the concentration range of 1.5-750 ng/mL with intra-day precision ≤8.3% and inter-day precision ≤14.6%. Additionally, accuracy was found to be ≤ 3.4%. In the pharmacokinetic study involving single oral doses of Q808 in Rhesus monkeys, Q808 was absorbed with a median time to peak plasma concentration ranging from 4.50-6.00 h and was eliminated with a terminal elimination half-life (t1/2) between 9.34-11.31 h. No definitive conclusion regarding linear pharmacokinetic characteristics could be drawn. The absolute bioavailability was determined as 20.95%, indicating limited systemic exposure after oral administration. Multiple dosing did not result in significant accumulation based on an accumulation factor Rac value of 1.31.

Conclusion

We have successfully developed and validated a rapid yet sensitive LC-MS/MS method for quantifying levels of Q808 in rhesus monkey plasma for the first time. The determination method and pharmacokinetic characteristics of Q808 in rhesus monkey support the next steps in drug development.

RNA Sequencing Demonstrates Ex Vivo Neocortical Transcriptomic Changes Induced by Epileptiform Activity in Male and Female Mice

Seizures are generally associated with epilepsy but may also be a symptom of many other neurological conditions. A hallmark of a seizure is the intensity of the local neuronal activation, which can drive large-scale gene transcription changes. Such changes in the transcriptional profile likely alter neuronal function, thereby contributing to the pathological process. Therefore, there is a strong clinical imperative to characterize how gene expression is changed by seizure activity. To this end, we developed a simplified ex vivo technique for studying seizure-induced transcriptional changes. We compared the RNA sequencing profile in mouse neocortical tissue with up to 3 h of epileptiform activity induced by 4-aminopyridine (4AP) relative to control brain slices not exposed to the drug. We identified over 100 genes with significantly altered expression after 4AP treatment, including multiple genes involved in MAPK, TNF, and neuroinflammatory signaling pathways, all of which have been linked to epilepsy previously. Notably, the patterns in male and female brain slices were almost identical. Various immediate early genes were among those showing the largest upregulation. The set of down-regulated genes included ones that might be expected either to increase or to decrease neuronal excitability. In summary, we found the seizure-induced transcriptional profile complex, but the changes aligned well with an analysis of published epilepsy-associated genes. We discuss how simple models may provide new angles for investigating seizure-induced transcriptional changes.

Effects of long-term administration of Q808 on hippocampal transcriptome in healthy rats

Epilepsy treatment with antiepileptic drugs (AEDs) is usually requires for many years. Q808 is an innovative antiepileptic chemical. It exerts effective antiepileptic effect against various epilepsy models. Exploring the gene transcriptomic profile of long-term treatment of Q808 is necessary. In the present study, hippocampus RNA-sequencing was performed to reveal the transcriptome profile of rats before and after treatment of Q808 for 28 days. Results confirmed 51 differentially expressed genes (DEGs) between Q808 and healthy control groups. Gene cluster analysis showed that most upregulated DEGs linked to response to drug and nucleus, most downregulated DEGs linked to locomotory, neuronal cell body, and drug binding. Most of DEGs were enriched in the signaling transduction, substance dependence, nervous system, and neurodegenerative disease pathways. Furthermore, quantitative real-time PCR analysis confirmed that Q808 significantly increased the expression of neuroprotective genes, such as Mdk, and decreased the mRNA levels of Penk, Drd1, and Adora2a, which are highly expressed in epilepsy models. In addition, Q808 decreased the mRNA expression of Pde10A and Drd2, which are known to be closely associated with schizophrenia. Our study may provide a theoretical basis to explore the effect of Q808 on the susceptibility to epilepsy and other neurological diseases.