Authors :
Presenting Author: yingting wang, MD student – Beijing tiantan hospital, Capital Medical University,China
Xiaorui Shi, MD student – Beijing tiantan hospital, Capital Medical University,China
Jianping Wu, PhD – Beijing tiantan hospital, Capital Medical University,China
Qun Wang, MD – Beijing Tiantan Hospital, Capital Medical University
Rationale:
Alzheimer's disease (AD) is one of the major diseases affecting the quality of life of the elderly, and the β-amyloid 1-42 oligomers (AβO1-42) play an important role in AD pathology. The incidence of epilepsy in AD patients is sharkly increasing. One of the molecular basis of AD with eplepsy is the abnormalities of ion channels like sodium channel plays very important role. The new generation of antiepileptic drug lacosamide (LCM) is widely used in the treatment of clinical eplepsy for enhancing slow inactivation of sodium channels. To investigate the efficacy of LCM in AD and epilepsy co-morbidities and its possible mechanisms, we conducted a molecular biology study to explore its effects on target voltage-gated sodium 1.6 (Nav1.6) channels in an AD cell model of AβO1-42-treated rat fetal hippocampal primary neurons, aiming to explore the potential of LCM in the treatment of AD with epilepsy.
Methods:
We first prepared AβO1-42 and verified its molecular composition according to the widely recognized oligomeric preparation methods. We then applied the CCK8 assay to determine the appropriate treatment concentration of AβO1-42 to establish the currently widely used AD cell model of AβO1-42-treated rat fetal rat hippocampal primary neurons(also called AD cell model). Then, we examined the expression of Nav1.6 channel at the translational level by conducting immunofluorescence and Western blot (WB) analysis. Furthermore，we tested the neuronal excitability of AD cell model by patch clamp assay. Finally, we treated this AD cell model with the antiepileptic drug LCM to observe the effect of LCM.
Results:
Immunofluorescence results demonstrated that green fluorescence of Nav1.6 channels was significantly enhanced in the AD cell model and the enhanced green fluorescence of Nav1.6 channels decreased after treated with LCM. Similarly, in the WB experiments, protein expression of Nav1.6 channels was significantly elevated in the AD cell model, whereas the increased protein expression of Nav1.6 channels was significantly decreasing after treaded with LCM. When comes to the function, the patch-clamp results suggested that the action potential (AP)frequency of AD cells model was significantly elevated. With the treatment of LCM, the AP frequency of AD cell model was partially reduced. Furthermore, AD cell model treated with LCM also showed that a significant decrease in the elevated peak amplitude, which indicated that LCM had an inhibitory effect on the elevated excitability of AD cell model, and further suggests that LCM has a potential for the treatment of AD combined with epilepsy.
Conclusions:
Nav1.6 channels, which are associated with nervous system excitability, were significantly increased in the AD cell model. LCM, a novel antiepileptic drug, partially ameliorated the elevated Nav1.6 channels and elevated neuronal excitability in the AD cell model and LCM has the potential to treat AD combined with epilepsy by a mechanism that may involves the alteration of Nav1.6 channels.
Funding:
1.National Natural Science Foundation of China, Grant/Award Number: 8237050142
2.National Natural Science Foundation of China Regional Joint Project, Grant/Award Number: U24A20695