The Effects of Moxibustion on Learning and Memory and m6A RNA Methylation in APP/PS1 Mice

Moxibustion improves hypothalamus Aqp4 polarization in APP/PS1 mice: Evidence from spatial transcriptomics

Aquaporin-4 (AQP4) is highly polarized to perivascular astrocytic endfeet. Loss of AQP4 polarization is associated with many diseases. In Alzheimer's disease (AD), AQP4 loses its normal location and thus reduces the clearance of amyloid-β plaques and tau protein. Clinical and experimental studies showed that moxibustion can improve the learning and memory abilities of AD. To explore whether moxibustion can affect the polarization of AQP4 around the blood-brain barrier (BBB), we used spatial transcriptomics (ST) to analyze the expression and polarization of Aqp4 in wild-type mice, APP/PS1 mice, and APP/PS1 mice intervened by moxibustion. The results showed that moxibustion improved the loss of abnormal polarization of AQP4 in APP/PS1 mice, especially in the hypothalamic BBB. Besides, the other 31 genes with Aqp4 as the core have similar depolarization in APP/PS1 mice, most of which are also membrane proteins. The majority of them have been reversed by moxibustion. At the same time, we employed the cerebrospinal fluid circulation gene set, which was found to be at a higher level in the group of APP/PS1 mice with moxibustion treatment. Finally, to further explore its mechanism, we analyzed the mitochondrial respiratory chain complex enzymes closely related to energy metabolism and found that moxibustion can significantly increase the expression of mitochondrial respiratory chain enzymes such as Cox6a2 in the hypothalamus, which could provide energy for mRNA transport. Our research shows that increasing the polarization of hypothalamic Aqp4 through mitochondrial energy supply may be an important target for moxibustion to improve cognitive impairment in APP/PS1 mice.

Donepezil ameliorates Aβ pathology but not tau pathology in 5xFAD mice

The cholinesterase inhibitor donepezil is used to improve Aβ pathology and cognitive function in patients with Alzheimer’s disease (AD). However, the impact of donepezil on tau pathology is unclear. Thus, we examined the effects of donepezil on Aβ and tau pathology in 5xFAD mice (a model of AD) in this study. We found that intraperitoneal injection of donepezil (1 mg/kg, i.p.) exhibited significant reductions in Aβ plaque number in the cortex and hippocampal DG region. In addition, donepezil treatment (1 mg/kg, i.p.) reduced Aβ-mediated microglial and, to a lesser extent, astrocytic activation in 5xFAD mice. However, neither intraperitoneal/oral injection of donepezil nor oral injection of rivastigmine altered tau phosphorylation at Thr212/Ser214 (AT100), Thr396, and Thr231 in 5xFAD mice. Surprisingly, we observed that intraperitoneal/oral injection of donepezil treatment significantly increased tau phosphorylation at Thr212 in 5xFAD mice. Taken together, these data suggest that intraperitoneal injection of donepezil suppresses Aβ pathology but not tau pathology in 5xFAD mice.