Mutations in the proline-rich transmembrane protein 2 (PRRT2) are associated with paroxysmal kinesigenic dyskinesia (PKD) and several other paroxysmal neurological diseases, but the PRRT2 function and pathogenic mechanisms remain largely obscure. Here we show that PRRT2 is a presynaptic protein that interacts with components of the SNARE complex and downregulates its formation. Loss-of-function mutant mice showed PKD-like phenotypes triggered by generalized seizures, hyperthermia, or optogenetic stimulation of the cerebellum. Mutant mice with specific PRRT2 deletion in cerebellar granule cells (GCs) recapitulate the behavioral phenotypes seen in Prrt2-null mice. Furthermore, recording made in cerebellar slices showed that optogenetic stimulation of GCs results in transient elevation followed by suppression of Purkinje cell firing. The anticonvulsant drug carbamazepine used in PKD treatment also relieved PKD-like behaviors in mutant mice. Together, our findings identify PRRT2 as a novel regulator of the SNARE complex and provide a circuit mechanism underlying the PRRT2-related behaviors.

The glycogen synthase kinase-3β (GSK3β) pathway plays a central role in Alzheimer's disease (AD) and its deregulation accounts for many of the pathological hallmarks of AD. Lithium, which modulates GSK3β activity, has been shown to reduce amyloid production and tau phosphorylation in pre-pathological AD mouse models. In this study, we investigated the effects of chronic LiCl treatment in aged double transgenic mice (AβPPSwe/PS1A246E). We found that chronic lithium treatment decreased the γ-cleavage of amyloid-β protein precursor, further reduced amyloid-β production and senile plaque formation, accompanied by the improvement in spatial learning and memory abilities. Because autophagy may play an important role in the pathology of AD, we also assessed the autophagy activity and found that the chronic lithium treatment attenuated the autophagy activation in this AD mouse model. Our results suggest that prolonged lithium treatment, even during the later stages of AD, could be an effective therapeutics.

Autophagy plays an important role in Alzheimer's disease (AD). It has been reported that autophagic flux is altered in patients with AD, and application of the autophagy enhancer rapamycin may alleviate the cognitive impairment and amyloid-β (Aβ) neuropathology in transgenic animal model of AD. Since rapamycin is also an immune suppressor, there is a concern that long-term use of rapamycin may bring severe unwanted side effects. The aim of this study is to test if carbamazepine (CBZ), an anti-epileptic drug that has a potent autophagy enhancement effect, has anti-AD effects in APP(swe)/PS1(deltaE9) transgenic mice model of AD. We found that APP(swe)/PS1(deltaE9) mice display increased autophagic activity accompanied by decreased mTOR activity. After three months treatment with CBZ in the APP(swe)/PS1(deltaE9) mice, we demonstrated that the spatial learning and memory deficits in these mice are significantly alleviated. We also documented that the cerebral amyloid plaque burden and Aβ42 levels in these mice are significantly reduced. Furthermore, we showed that CBZ significantly enhances the autophagic flux in the APP(swe)/PS1(deltaE9) mice which is unlikely via mTOR-dependent autophagy pathway. These data suggest that long-term CBZ treatment may have a protective effect in AD mouse model possibly through enhancing the autophagic flux.